EXHIBIT B

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Exhibit A-20

Invalidity Claim Chart for U.S. Patent No. 7,924,802 vs. U.S. Patent No. 7,742,388

U.S. Patent No. 7,742,388 (“Shearer”) was filed on July 20, 2005, published on January 26, 2006 (U.S. Patent Application Publication 

No. 2006/0018249), and issued on June 22, 2010. Shearer anticipates asserted claims 1–4, 6–10, 13, 14, 17, and 21–24 of U.S. Patent 

No. 7,924,802 (“the ’802 Patent”) under 35 U.S.C. § 102. Shearer also renders obvious asserted claims 1–4, 6–10, 13, 14, 17, and 21–

24 of the ’802 Patent under 35 U.S.C. § 103, alone based on the state of the art and/or in combination with one or more other 

references identified in Exs. A-1–A-31, Cover Pleading, and First Supplemental Ex. A-Obviousness Chart.

1

 

To the extent Plaintiff alleges that Shearer does not disclose any particular limitation of the asserted claims in the ’802 Patent, either 

expressly or inherently, it would have been obvious to a person of ordinary skill in the art as of the priority date of the ’802 Patent to 

modify Shearer and/or to combine the teachings of Shearer with other prior art references, including but not limited to the present 

prior art references found in Exs. A-1–A-31, Cover Pleading, First Supplemental Ex. A-Obviousness Chart, and the relevant section of 

charts for other prior art for the ’802 Patent in a manner that would render the asserted claims of these patents invalid as obvious.

With respect to the obviousness of the asserted claims of the ’802 Patent under 35 U.S.C. § 103, one or more of the principles 

enumerated by the United States Supreme Court in KSR v. Teleflex, 550 U.S. 398 (2007) apply, including: (a) combining various 

claimed elements known in the prior art according to known methods to yield a predictable result; and/or (b) making a simple 

substitution of one or more known elements for another to obtain a predictable result; and/or (c) using a known technique to improve a 

similar device or method in the same way; and/or (d) applying a known technique to a known device or method ready for 

improvement to yield a predictable result; and/or (e) choosing from a finite number of identified, predictable solutions with a 

reasonable expectation of success or, in other words, the solution was one which was “obvious to try”; and/or (f) a known work in one 

field of endeavor prompting variations of it for use either in the same field or a different field based on given design incentives or 

other market forces in which the variations were predictable to one of ordinary skill in the art; and/or (g) a teaching, suggestion, or 

motivation in the prior art that would have led one of ordinary skill in the art to modify the prior art reference or to combine the 

teachings of various prior art references to arrive at the claimed invention. It therefore would have been obvious to one of ordinary 

skill in the art to combine the disclosures of these references in accordance with the principles and rationales set forth above. 

1

 Samsung is investigating this prior art and has not yet completed discovery from third parties, who may have relevant information 

concerning the prior art, and therefore, Samsung reserves the right to supplement this chart after additional discovery is received. To 

the extent that any of the prior art discloses the same or similar functionality or feature(s) of any of the accused products, Samsung

reserves the right to argue that said feature or functionality does not practice any limitation of any of the asserted claims, and to argue, 

in the alternative, that if said feature or functionality is found to practice any limitation of any of the asserted claims in the ’802 Patent, 

then the prior art reference teaches the limitation and that the claim is not patentable. 

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The citations to portions of any reference in this chart are exemplary only. For example, a citation that refers to or discusses a figure or 

figure item should be understood to also incorporate by reference that figure and any additional descriptions of that figure as if set 

forth fully therein. Samsung reserves the right to rely on the entirety of the references cited in this chart to show that the asserted 

claims of the ’802 Patent are invalid. Citations presented for one claim limitation are expressly incorporated by reference into all 

other limitations for that claim as well as all limitations of all claims on which that claim depends. Samsung also reserves the right to 

rely on additional citations or sources of evidence that also may be applicable, or that may become applicable in light of cl aim 

construction, changes in Plaintiff’s infringement contentions, and/or information obtained during discovery as the c ase progresses. 

Claim 1 of the ’802 Patent Prior Art Reference – Shearer

[1.1] A method of 

transmitting information in a 

wireless communication 

channel comprising:

To the extent the preamble is limiting, Shearer discloses “A method of transmitting information in a 

wireless communication channel comprising.” See, e.g.: 

Disclosed herein are various embodiments of methods, systems, and apparatus for increasing packet 

generation in a digital communication system. In one exemplary method embodiment, subcarriers are 

added to a packet in a wireless local area network transmission to increase the data rate.

See, e.g., Shearer at Abstract.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

See, e.g., Shearer at 1:31-38.

802.11 is directed to wireless LANs, and in particular specifies the MAC and the PHY layers. These 

layers are intended to correspond closely to the two lowest layers of a system based on the ISO Basic 

Reference Model of OSI, i.e., the data link layer and the physical layer. FIG. 1 shows a diagrammatic 

representation of an open systems interconnection (OSI) layered model 100 developed by the 

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Claim 1 of the ’802 Patent Prior Art Reference – Shearer

International Organization for Standards (ISO) for describing the exchange of information between 

layers in communication networks. The OSI layered model 100 is particularly useful for separating 

the technological functions of each layer, and thereby facilitating the modification or update of a 

given layer without detrimentally impacting on the functions of neighboring layers.

See, e.g., Shearer at 3:61-4:7.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Refe rring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

See, e.g., Shearer at 4:62-5:4.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[1.2] transmitting first 

information across a first 

frequency range using a 

wireless transmitter, the first 

frequency range having a first 

center frequency, a first 

Shearer discloses “transmitting first information across a first frequency range using a wireless 

transmitter, the first frequency range having a first center frequency, a first highest frequency, and a 

first lowest frequency.” See, e.g.: 

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Claim 1 of the ’802 Patent Prior Art Reference – Shearer

highest frequency, and a first 

lowest frequency; and

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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Claim 1 of the ’802 Patent Prior Art Reference – Shearer

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inpu ts, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[1.3] simultaneously 

transmitting second 

information across a second 

frequency range using the 

same wireless transmitter, the 

second frequency range 

having a second center 

frequency greater than the 

Shearer discloses “simultaneously transmitting second information across a second frequency range 

using the same wireless transmitter, the second frequency range having a second center frequency 

greater than the first center frequency, a second highest frequency, and a second lowest frequency.” 

See, e.g.: 

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first center frequency, a 

second highest frequency, and 

a second lowest frequency.

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subseq uently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first process ed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at cente r frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 2 of the ’802 Patent Prior Art Reference – Shearer

[2.1] The method of claim 1 Shearer discloses all the elements of claim 1 for all the reasons provided above.

[2.2] wherein frequency 

difference between the first 

center frequency and the 

Shearer discloses “wherein frequency difference between the first center frequency and the second 

center frequency is greater than the sum of one-half the first frequency range and one-half the second 

frequency range.” See, e.g.: 

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second center frequency is 

greater than the sum of onehalf the first frequency range 

and one-half the second 

frequency range.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

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The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

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See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 80 2.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

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An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

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If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 14.

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Claim 2 of the ’802 Patent Prior Art Reference – Shearer

See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 3 of the ’802 Patent Prior Art Reference – Shearer

[3.1] The method of claim 1 Shearer discloses all the elements of claim 1 for all the reasons provided above.

[3.2] wherein the first and 

second information are 

transmitted using the same 

Shearer discloses “wherein the first and second information are transmitted using the same power 

amplifier in said wireless transmitter.” See, e.g.: 

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power amplifier in said 

wireless transmitter.

See, e.g., Shearer at Figure 3.

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See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

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In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

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Claim 3 of the ’802 Patent Prior Art Reference – Shearer

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 4 of the ’802 Patent Prior Art Reference – Shearer

[4.1] The method of claim 3 Shearer discloses all the elements of claim 3 for all the reasons provided above.

[4.2] wherein the bandwidth 

of said power amplifier is 

greater than the difference 

between the first lowest 

frequency and the second 

highest frequency.

Shearer discloses “wherein the bandwidth of said power amplifier is greater than the difference 

between the first lowest frequency and the second highest frequency.” See, e.g.: 

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See, e.g., Shearer at Figure 3.

See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 14.

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Claim 4 of the ’802 Patent Prior Art Reference – Shearer

See, e.g., Shearer at Figure 16.

In an IEEE 802.11 system, as shown in FIG. 7, there is gap 702, 708, 714 between adjacent channels. 

FIG. 7 provides three different ways to create a 40 MHz wide packet subcarrier layout. Waveform 

700 provides a 40 MHz packet's subcarrier structure matching the subcarrier structure of two 20 MHz 

802.11a/g OFDM packets, whose center frequencies are spaced by 10 MHz. Waveform 706 adds 

extra subcarriers to the gap in the middle, on the inner spectral edges of the two 20 MHz sub-packets. 

Waveform 712 adds extra subcarriers to the outer and inner edges of the sub-packets. Each of these 

40 MHz constructions 700, 706, 712, is advantageous to a receiver, since the similarity in subcarrier 

layout facilitates processing in the receiver, especially, in the instance when a 20 MHz packet is 

received in either the upper or lower 20 MHz channel of the 40 MHz wide bandwidth, for example.

See, e.g., Shearer at 6:29-44.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

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If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 6 of the ’802 Patent Prior Art Reference – Shearer

[6.1] The method of claim 1 Shearer discloses all the elements of claim 1 for all the reasons provided above.

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[6.2] wherein the first 

information corresponds to a 

first wireless protocol and the 

second information 

corresponds to a second 

wireless protocol.

Shearer discloses “wherein the first information corresponds to a first wireless protocol and the 

second information corresponds to a second wireless protocol.” See, e.g.: 

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, co nnected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

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with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first process ed 

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

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FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at cente r frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

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Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 7 of the ’802 Patent Prior Art Reference – Shearer

[7.1] The method of claim 1 Shearer discloses all the elements of claim 1 for all the reasons provided above.

[7.2] wherein the first 

information and the second 

information are the same data 

transmitted across two 

different frequencies.

Shearer discloses “wherein the first information and the second information are the same data 

transmitted across two different frequencies.” See, e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 8 of the ’802 Patent Prior Art Reference – Shearer

[8.1] The method of claim 1 Shearer discloses all the elements of claim 1 for all the reasons provided above.

[8.2] wherein the first 

information and the second 

Shearer discloses “wherein the first information and the second information are from the same data 

stream.” See, e.g.: 

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information are from the same 

data stream.

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

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computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

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During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

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channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

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lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first process ed 

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at cente r frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

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received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

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transmission. This process is applicable for any even number of input signals. Each simultaneous 

input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 9 of the ’802 Patent Prior Art Reference – Shearer

[9.1] The method of claim 1 Shearer discloses all the elements of claim 1 for all the reasons provided above.

[9.2] wherein first information 

and second information 

comprise a plurality of OFDM 

Shearer discloses “wherein first information and second information comprise a plurality of OFDM 

symbols, wherein a first symbol is transmitted during a first time slot across the first frequency range 

and a second symbol is transmitted during the first time slot across the second frequency range, and 

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symbols, wherein a first 

symbol is transmitted during a 

first time slot across the first 

frequency range and a second 

symbol is transmitted during 

the first time slot across the 

second frequency range, and 

wherein a third symbol is 

transmitted during a second 

time slot across the first 

frequency range and a fourth 

symbol is transmitted during 

the second time slot across a 

second frequency range.

wherein a third symbol is transmitted during a second time slot across the first frequency range and a 

fourth symbol is transmitted during the second time slot across a second frequency range.” See, e.g.: 

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

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modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first process ed 

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

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shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at cente r frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

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See, e.g., Shearer at 8:17-9:24.

FIG. 19 is a graph of each signal and its frequency vs. time relationship. Each signal's start time 1902 

and end time 1904 is preferably substantially equivalent to eliminate problems with multiple signal 

acquisition and termination. These problems may include transmitting and receiving simultaneously. 

By occupying “both” channels at the same time, simultaneous transmitting and receiving is enabled.

See, e.g., Shearer at 10:31-38.

An exemplary embodiment can support two types of packets, for example, for both 20 MHz and 40 

MHz. The subcarrier alignment and receive detection methods detailed above apply to many 

nonlimiting packet types. One type of packet, as provided in FIG. 21, is a mixed-mode packet, which 

has the spectrally aligned legacy preamble/ header 2102, 2104, 2106, the extended header 2108, 

2110, and data symbols 2112. A mixed-mode packet can occur for both 20 MHz and 40 MHz 

packets. In this case, it is important for legacy radios to see a legacy preamble/header. As such, a 

mixed-mode packet can start with a legacy preamble/ header 2102, 2104, 2106 and then follow with 

additional extended header/ preamble signal 2108, 2110. With mixed mode, the legacy radio receives 

what looks like a legacy packet, so it remains dormant through the following extended part. This 

allows for reception of legacy packets by legacy radios without disruption by an extended packet. 

This is sometimes referred to as spoofing a legacy radio.

As provided in FIG. 22, a second type of packet 2200 is called Greenfield, which can occur for both 

20 MHz and 40 MHz packets. In this case, it is not necessary to have a legacy radio process the 

packet. A Greenfield packet 2200 can be used in an environment (or time slot) where no legacy 

radios are receiving. As such, the packet begins immediately with an extended preamble/ header 

2202, 2204, 2206, followed by data symbols 2208.

See, e.g., Shearer at 11:23-48.

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See, e.g., Shearer at Figure 19.

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See, e.g., Shearer at Figure 21.

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See, e.g., Shearer at Figure 22.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

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motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 10 of the ’802 Patent Prior Art Reference – Shearer

[10.1] A method of 

transmitting information in a 

wireless communication 

channel comprising:

To the extent the preamble is limiting, Shearer discloses “A method of transmitting information in a 

wireless communication channel comprising.” See, e.g.: 

Disclosed herein are various embodiments of methods, systems, and apparatus for increasing packet 

generation in a digital communication system. In one exemplary method embodiment, subcarriers are 

added to a packet in a wireless local area network transmission to increase the data rate.

See, e.g., Shearer at Abstract.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

See, e.g., Shearer at 1:31-38.

802.11 is directed to wireless LANs, and in particular specifies the MAC and the PHY layers. These 

layers are intended to correspond closely to the two lowest layers of a system based on the ISO Basic 

Reference Model of OSI, i.e., the data link layer and the physical layer. FIG. 1 shows a diagrammatic 

representation of an open systems interconnection (OSI) layered model 100 developed by the 

International Organization for Standards (ISO) for describing the exchange of information between 

layers in communication networks. The OSI layered model 100 is particularly useful for separating 

the technological functions of each layer, and thereby facilitating the modification or update of a 

given layer without detrimentally impacting on the functions of neighboring layers.

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See, e.g., Shearer at 3:61-4:7.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

See, e.g., Shearer at 4:62-5:4.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[10.2] receiving a first digital 

signal comprising first data to 

be transmitted;

Shearer discloses “receiving a first digital signal comprising first data to be transmitted.” See, e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first process ed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at cente r frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[10.3] receiving a second 

digital signal comprising 

second data to be transmitted;

Shearer discloses “receiving a second digital signal comprising second data to be transmitted.” See, 

e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification , all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processe d 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[10.4] converting the first 

digital signal into a first 

analog signal using a first 

digital-to-analog converter, 

the first analog signal carrying 

the first data across a first 

frequency range;.

Shearer discloses “converting the first digital signal into a first analog signal using a first digital-toanalog converter, the first analog signal carrying the first data across a first frequency range.” See, 

e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can commun icate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion f ocuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[10.5] converting the second 

digital signal into a second 

analog signal using a second 

digital-to-analog converter, 

the second analog signal 

carrying the second data 

across a second frequency 

range;

Shearer discloses “converting the second digital signal into a second analog signal using a second 

digital-to-analog converter, the second analog signal carrying the second data across a second 

frequency range.” See, e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[10.6] up-converting the first 

analog signal to a first RF 

center frequency to produce a 

first up-converted analog 

signal, wherein the first upconverted analog signal 

comprises a first up-converted 

frequency range from the first 

Shearer discloses “up-converting the first analog signal to a first RF center frequency to produce a 

first up-converted analog signal, wherein the first up-converted analog signal comprises a first upconverted frequency range from the first RF center frequency minus one-half the first frequency 

range to the first RF center frequency plus one-half the first frequency range.” See, e.g.: 

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RF center frequency minus 

one-half the first frequency 

range to the first RF center 

frequency plus one-half the 

first frequency range;

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogona l properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulato r 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[10.7] up-converting the 

second analog signal to a 

second RF center frequency 

greater than the first center RF 

frequency to produce a second 

up-converted analog signal, 

wherein the second upconverted analog signal 

Shearer discloses “up-converting the second analog signal to a second RF center frequency greater 

than the first center RF frequency to produce a second up-converted analog signal, wherein the 

second up-converted analog signal comprises a second up-converted frequency range from the 

second RF center frequency minus one-half the second frequency range to the second RF center 

frequency plus one-half the second frequency range, and wherein a frequency difference between the 

first RF center frequency and the second RF center frequency is greater than the sum of one-half the 

first frequency range and one-half the second frequency range.” See, e.g.: 

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comprises a second upconverted frequency range 

from the second RF center 

frequency minus one-half the 

second frequency range to the 

second RF center frequency 

plus one-half the second 

frequency range, and wherein 

a frequency difference 

between the first RF center 

frequency and the second RF 

center frequency is greater 

than the sum of one-half the 

first frequency range and onehalf the second frequency 

range;

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

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the terminals are capable of communicating with at least two of the access points when located within 

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

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During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as desc ribed below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

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channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.1 1a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

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lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

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received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

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transmission. This process is applicable for any even number of input signals. Each simultaneous 

input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[10.8] combining the first upconverted analog signal and 

the second up-converted 

analog signal to produce a 

combined up-converted 

signal;

Shearer discloses “combining the first up-converted analog signal and the second up-converted 

analog signal to produce a combined up-converted signal.” See, e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[10.9] amplifying the 

combined up-converted signal 

in a power amplifier resulting 

in an amplified combined upconverted signal; and

Shearer discloses “amplifying the combined up-converted signal in a power amplifier resulting in an 

amplified combined up-converted signal.” See, e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogona l properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulato r 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[10.10] transmitting the 

amplified combined upconverted signal on a first 

antenna,

Shearer discloses “transmitting the amplified combined up-converted signal on a first antenna.” See, 

e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coh erent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuf fing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz downshifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[10.11] wherein the 

bandwidth of said power 

amplifier is greater than the 

difference between a lowest 

frequency in the first upconverted frequency range 

and a highest frequency in the 

Shearer discloses “wherein the bandwidth of said power amplifier is greater than the difference 

between a lowest frequency in the first up-converted frequency range and a highest frequency in the 

second up-converted frequency range.” See, e.g.: 

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second up-converted 

frequency range.

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 13 of the ’802 Patent Prior Art Reference – Shearer

[13.1] The method of claim 10 Shearer discloses all the elements of claim 10 for all the reasons provided above.

[13.2] wherein the first digital 

signal is encoded using a first 

wireless protocol and the 

Shearer discloses “wherein the first digital signal is encoded using a first wireless protocol and the 

second digital signal is encoded using a second wireless protocol.” See, e.g.: 

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second digital signal is 

encoded using a second 

wireless protocol.

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

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the terminals are capable of communicating with at least two of the access points when located within 

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

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During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

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channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

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lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first process ed 

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at cente r frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

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received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

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transmission. This process is applicable for any even number of input signals. Each simultaneous 

input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 14 of the ’802 Patent Prior Art Reference – Shearer

[14.1] The method of claim 10 Shearer discloses all the elements of claim 10 for all the reasons provided above.

[14.2] wherein the second 

data is the same as the first 

Shearer discloses “wherein the second data is the same as the first data, the method further 

comprising.” See, e.g.: 

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data, the method further 

comprising:

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which a t least some of 

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the terminals are capable of communicating with at least two of the access points when located within 

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to elimina te “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

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During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subseq uently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

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channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

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lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

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received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

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transmission. This process is applicable for any even number of input signals. Each simultaneous 

input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[14.3] receiving the 

transmitted signal on a second 

antenna;

Shearer discloses “receiving the transmitted signal on a second antenna.” See, e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogona l properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulato r 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[14.4] amplifying the received 

signal in a low noise amplifier 

resulting in an amplified 

received up-converted signal, 

wherein the bandwidth of said 

low noise amplifier is greater 

than the difference between 

the lowest frequency in the 

Shearer discloses “amplifying the received signal in a low noise amplifier resulting in an amplified 

received up-converted signal, wherein the bandwidth of said low noise amplifier is greater than the 

difference between the lowest frequency in the first up-converted frequency range and the highest 

frequency in the second up-converted frequency range.” See, e.g.: 

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first up-converted frequency 

range and the highest 

frequency in the second upconverted frequency range;

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[14.5] down-converting the 

amplified received upconverted signal using a first 

down-converter and a signal 

corresponding to the first RF 

center frequency to produce a 

fourth analog signal 

Shearer discloses “down-converting the amplified received up-converted signal using a first downconverter and a signal corresponding to the first RF center frequency to produce a fourth analog 

signal corresponding to the first analog signal.” See, e.g.: 

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corresponding to the first 

analog signal; and

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogona l properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulato r 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[14.6] down-converting the 

amplified received upconverted analog signal using 

a second down-converter and 

a signal corresponding to the 

second RF center frequency to 

produce a fifth analog signal 

Shearer discloses “down-converting the amplified received up-converted analog signal using a 

second down-converter and a signal corresponding to the second RF center frequency to produce a 

fifth analog signal corresponding to the second analog signal.” See, e.g.: 

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corresponding to the second 

analog signal.

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification , all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processe d 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 17 of the ’802 Patent Prior Art Reference – Shearer

[17.1] A wireless 

communication system 

comprising:

To the extent the preamble is limiting, Shearer discloses “A wireless communication system 

comprising.” See, e.g.: 

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Disclosed herein are various embodiments of methods, systems, and apparatus for increasing packet 

generation in a digital communication system. In one exemplary method embodiment, subcarriers are 

added to a packet in a wireless local area network transmission to increase the data rate.

See, e.g., Shearer at Abstract.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

See, e.g., Shearer at 1:31-38.

802.11 is directed to wireless LANs, and in particular specifies the MAC and the PHY layers. These 

layers are intended to correspond closely to the two lowest layers of a system based on the ISO Basic 

Reference Model of OSI, i.e., the data link layer and the physical layer. FIG. 1 shows a diagrammatic 

representation of an open systems interconnection (OSI) layered model 100 developed by the 

International Organization for Standards (ISO) for describing the exchange of information between 

layers in communication networks. The OSI layered model 100 is particularly useful for separating 

the technological functions of each layer, and thereby facilitating the modification or update of a 

given layer without detrimentally impacting on the functions of neighboring layers.

See, e.g., Shearer at 3:61-4:7.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

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See, e.g., Shearer at 4:62-5:4.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[17.2] a baseband digital 

system for providing a first 

digital signal comprising a 

first data to be transmitted and 

a second digital signal 

comprising a second data to 

be transmitted;

Shearer discloses “a baseband digital system for providing a first digital signal comprising a first data 

to be transmitted and a second digital signal comprising a second data to be transmitted.” See, e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can commu nicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 3 14, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz downshifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[17.3] a first digital-to-analog 

converter for receiving the 

first digital signal and 

converting the first digital 

signal into a first analog 

signal, the first analog signal 

carrying the first data across a 

first frequency range;

Shearer discloses “a first digital-to-analog converter for receiving the first digital signal and 

converting the first digital signal into a first analog signal, the first analog signal carrying the first 

data across a first frequency range.” See, e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[17.4] a second digital-toanalog converter for receiving 

the second digital signal and 

converting the second digital 

signal into a second analog 

signal, the second analog 

signal carrying the second 

Shearer discloses “a second digital-to-analog converter for receiving the second digital signal and 

converting the second digital signal into a second analog signal, the second analog signal carrying the 

second data across a second frequency range.” See, e.g.: 

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data across a second 

frequency range;

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification , all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processe d 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[17.5] a first up-converter 

circuit having a first input 

coupled to receive the first 

analog signal and a second 

input coupled to receive a first 

modulation signal having a 

first RF frequency, wherein 

the first up-converter outputs 

Shearer discloses “a first up-converter circuit having a first input coupled to receive the first analog 

signal and a second input coupled to receive a first modulation signal having a first RF frequency, 

wherein the first up-converter outputs a first up-converted analog signal comprising a first upconverted frequency range from the first RF frequency minus one-half the first frequency range to the 

first RF frequency plus one-half the first frequency range.” See, e.g.: 

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a first up-converted analog 

signal comprising a first upconverted frequency range 

from the first RF frequency 

minus one-half the first 

frequency range to the first 

RF frequency plus one-half 

the first frequency range;

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz downshifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[17.6] a second up-converter 

circuit having a first input 

coupled to receive the second 

analog signal and a second 

input coupled to receive a 

second modulation signal 

having a second RF 

frequency, wherein the second 

Shearer discloses “a second up-converter circuit having a first input coupled to receive the second 

analog signal and a second input coupled to receive a second modulation signal having a second RF 

frequency, wherein the second up-converter outputs a second up-converted analog signal comprising 

a second up-converted frequency range from the second RF frequency minus one-half the second 

frequency range to the second RF frequency plus one-half the second frequency range, and wherein

frequency difference between the first RF frequency and the second RF frequency is greater than the 

sum of one-half the first frequency range and one-half the second frequency range.” See, e.g.: 

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up-converter outputs a second 

up-converted analog signal 

comprising a second upconverted frequency range 

from the second RF frequency 

minus one-half the second 

frequency range to the second 

RF frequency plus one-half 

the second frequency range, 

and wherein frequency 

difference between the first 

RF frequency and the second 

RF frequency is greater than 

the sum of one-half the first 

frequency range and one-half 

the second frequency range; 

and

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wir ed or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

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the terminals are capable of communicating with at least two of the access points when located within 

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

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During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

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channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification , all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

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lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processe d 

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

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received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

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transmission. This process is applicable for any even number of input signals. Each simultaneous 

input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[17.7] a power amplifier 

coupled to receive the first 

and second up-converted 

analog signals, wherein the 

bandwidth of the power 

amplifier is greater than the 

difference between a lowest 

frequency in the first upShearer discloses “a power amplifier coupled to receive the first and second up-converted analog 

signals, wherein the bandwidth of the power amplifier is greater than the difference between a lowest 

frequency in the first up-converted frequency range and a highest frequency in the second upconverted frequency range.” See, e.g.: 

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converted frequency range 

and a highest frequency in the 

second up-converted 

frequency range.

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Depa rtment, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification , all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processe d 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 21 of the ’802 Patent Prior Art Reference – Shearer

[21.1] The communication 

system of claim 17

Shearer discloses all the elements of claim 17 for all the reasons provided above.

[21.2] wherein the first data of 

the first digital signal is 

encoded using a first wireless 

protocol and the first data of 

the second digital signal is 

encoded using a second 

wireless protocol.

Shearer discloses “wherein the first data of the first digital signal is encoded using a first wireless 

protocol and the first data of the second digital signal is encoded using a second wireless protocol.” 

See, e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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Claim 21 of the ’802 Patent Prior Art Reference – Shearer

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subseq uently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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Claim 21 of the ’802 Patent Prior Art Reference – Shearer

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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Claim 21 of the ’802 Patent Prior Art Reference – Shearer

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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Claim 21 of the ’802 Patent Prior Art Reference – Shearer

input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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See, e.g., Shearer at Figure 14.

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See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these reference s. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 22 of the ’802 Patent Prior Art Reference – Shearer

[22.1] The communication 

system of claim 17

Shearer discloses all the elements of claim 17 for all the reasons provided above.

[22.2] wherein the second 

data corresponds to the first 

data and wherein the power 

Shearer discloses “wherein the second data corresponds to the first data and wherein the power 

amplifier outputs a third up-converted signal comprising the up-converted first analog signal and the 

up-converted second analog signal.” See, e.g.: 

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Claim 22 of the ’802 Patent Prior Art Reference – Shearer

amplifier outputs a third upconverted signal comprising 

the up-converted first analog 

signal and the up-converted 

second analog signal.

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

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Claim 22 of the ’802 Patent Prior Art Reference – Shearer

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

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During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subseq uently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

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channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

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lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

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received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

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transmission. This process is applicable for any even number of input signals. Each simultaneous 

input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

See, e.g., Shearer at Figure 8.

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See, e.g., Shearer at Figure 9.

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See, e.g., Shearer at Figure 10.

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See, e.g., Shearer at Figure 11.

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See, e.g., Shearer at Figure 12.

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See, e.g., Shearer at Figure 13.

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Claim 22 of the ’802 Patent Prior Art Reference – Shearer

See, e.g., Shearer at Figure 14.

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Claim 22 of the ’802 Patent Prior Art Reference – Shearer

See, e.g., Shearer at Figure 16.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 23 of the ’802 Patent Prior Art Reference – Shearer

[23.1] The communication 

system of claim 17

Shearer discloses all the elements of claim 17 for all the reasons provided above.

[23.2] wherein first and 

second data to be transmitted 

comprise a plurality of OFDM 

Shearer discloses “wherein first and second data to be transmitted comprise a plurality of OFDM 

symbols, wherein a first symbol is transmitted during a first time slot across the first up-converted 

frequency range and a second symbol is transmitted during the first time slot across the second up -

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symbols, wherein a first 

symbol is transmitted during a 

first time slot across the first 

up-converted frequency range 

and a second symbol is 

transmitted during the first 

time slot across the second 

up-converted frequency range, 

and wherein a third symbol is 

transmitted during a second 

time slot across the first upconverted frequency range 

and a fourth symbol is 

transmitted during the second 

time slot across a second upconverted frequency range.

converted frequency range, and wherein a third symbol is transmitted during a second time slot 

across the first up-converted frequency range and a fourth symbol is transmitted during the second 

time slot across a second up-converted frequency range.” See, e.g.: 

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

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packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first process ed 

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

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The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at cente r frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

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FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

FIG. 19 is a graph of each signal and its frequency vs. time relationship. Each signal's start time 1902 

and end time 1904 is preferably substantially equivalent to eliminate problems with multiple signal 

acquisition and termination. These problems may include transmitting and receiving simultaneously. 

By occupying “both” channels at the same time, simultaneous transmitting and receiving is enabled.

See, e.g., Shearer at 10:31-38.

An exemplary embodiment can support two types of packets, for example, for both 20 MHz and 40 

MHz. The subcarrier alignment and receive detection methods detailed above apply to many 

nonlimiting packet types. One type of packet, as provided in FIG. 21, is a mixed-mode packet, which 

has the spectrally aligned legacy preamble/ header 2102, 2104, 2106, the extended header 2108, 

2110, and data symbols 2112. A mixed-mode packet can occur for both 20 MHz and 40 MHz 

packets. In this case, it is important for legacy radios to see a legacy preamble/header. As such, a 

mixed-mode packet can start with a legacy preamble/ header 2102, 2104, 2106 and then follow with 

additional extended header/ preamble signal 2108, 2110. With mixed mode, the legacy radio receives 

what looks like a legacy packet, so it remains dormant through the following extended part. This 

allows for reception of legacy packets by legacy radios without disruption by an extended packet. 

This is sometimes referred to as spoofing a legacy radio.

As provided in FIG. 22, a second type of packet 2200 is called Greenfield, which can occur for both 

20 MHz and 40 MHz packets. In this case, it is not necessary to have a legacy radio process the 

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packet. A Greenfield packet 2200 can be used in an environment (or time slot) where no legacy 

radios are receiving. As such, the packet begins immediately with an extended preamble/ header 

2202, 2204, 2206, followed by data symbols 2208.

See, e.g., Shearer at 11:23-48.

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See, e.g., Shearer at Figure 19.

See, e.g., Shearer at Figure 21.

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See, e.g., Shearer at Figure 22.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

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motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

Claim 24 of the ’802 Patent Prior Art Reference – Shearer

[24.1] An electronic circuit 

comprising:

To the extent the preamble is limiting, Shearer discloses “An electronic circuit comprising.” See, 

e.g.: 

Disclosed herein are various embodiments of methods, systems, and apparatus for increasing packet 

generation in a digital communication system. In one exemplary method embodiment, subcarriers are 

added to a packet in a wireless local area network transmission to increase the data rate.

See, e.g., Shearer at Abstract.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

See, e.g., Shearer at 1:31-38.

802.11 is directed to wireless LANs, and in particular specifies the MAC and the PHY layers. These 

layers are intended to correspond closely to the two lowest layers of a system based on the ISO Basic 

Reference Model of OSI, i.e., the data link layer and the physical layer. FIG. 1 shows a diagrammatic 

representation of an open systems interconnection (OSI) layered model 100 developed by the 

International Organization for Standards (ISO) for describing the exchange of information between 

layers in communication networks. The OSI layered model 100 is particularly useful for separating 

the technological functions of each layer, and thereby facilitating the modification or update of a 

given layer without detrimentally impacting on the functions of neighboring layers.

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

See, e.g., Shearer at 3:61-4:7.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

See, e.g., Shearer at 4:62-5:4.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[24.2] a first down-converter 

circuit having a first input 

coupled to receive a first upconverted signal, a second 

input coupled to receive a first 

demodulation signal having a 

first RF frequency, and an 

output, wherein the first 

down-converter circuit 

outputs a first down-converted 

Shearer discloses “a first down-converter circuit having a first input coupled to receive a first upconverted signal, a second input coupled to receive a first demodulation signal having a first RF 

frequency, and an output, wherein the first down-converter circuit outputs a first down-converted 

signal on the first down-converter output.” See, e.g.: 

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

signal on the first downconverter output;

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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440

Claim 24 of the ’802 Patent Prior Art Reference – Shearer

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification , all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first process ed 

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at cente r frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[24.3] a second downconverter circuit having a first 

input coupled to receive the 

first up-converted signal, a 

second input coupled to 

receive a second 

demodulation signal having a 

second RF frequency different 

than the first RF frequency, 

and an output, wherein the 

second down-converter 

outputs a second downconverted signal on the 

second down-converter 

Shearer discloses “a second down-converter circuit having a first input coupled to receive the first upconverted signal, a second input coupled to receive a second demodulation signal having a second RF 

frequency different than the first RF frequency, and an output, wherein the second down -converter 

outputs a second down-converted signal on the second down-converter output, wherein the first upconverted signal comprises a first signal modulated at the first RF frequency and a second signal 

modulated at the second RF frequency.” See, e.g.: 

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

output, wherein the first upconverted signal comprises a 

first signal modulated at the 

first RF frequency and a 

second signal modulated at 

the second RF frequency; and

See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogona l properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulato r 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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Claim 24 of the ’802 Patent Prior Art Reference – Shearer

discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and center 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

[24.4] a filter having an input 

coupled to the output of the 

first down-converter and the 

output of the second downconverter, and in accordance 

therewith, the filter receives 

the first and second downconverted signals.

Shearer discloses “a filter having an input coupled to the output of the first down-converter and the 

output of the second down-converter, and in accordance therewith, the filter receives the first and 

second down-converted signals.” See, e.g.: 

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See, e.g., Shearer at Figure 3.

A wireless local area network (LAN) typically uses infrared (IR) or radio frequency (RF) 

communications channels to communicate between portable or mobile computer terminals and 

stationary access points or base stations. These access points are, in turn, connected by a wired or 

wireless communications channel to a network infrastructure which connects groups of access points 

together to form the LAN, including, optionally, one or more host computer systems.

Wireless protocols such as Bluetooth and IEEE 802.11 support the logical interconnections of such 

portable roaming terminals having a variety of types of communication capabilities to host 

computers. The logical interconnections are based upon an infrastructure in which at least some of 

the terminals are capable of communicating with at least two of the access points when located within 

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a predetermined range, each terminal being normally associated, and in communication, with a single 

one of the access points. Based on the overall spatial layout, response time, and loading requirements 

of the network, different networking schemes and communication protocols have been designed so as 

to most efficiently regulate the communications.

IEEE Standard 802.11 (“802.11”) is set out in “Wireless LAN Medium Access Control (MAC) and 

Physical Layer (PHY) Specifications” and is available from the IEEE Standards Department, 

Piscataway, N.J. 802.11 permits either IR or RF communications at 1 Mbps, 2 Mbps and higher data 

rates, a medium access technique similar to carrier sense multiple access/collision avoidance 

(CSMA/CA), a power-save mode for battery-operated mobile stations, seamless roaming in a full 

cellular network, high throughput operation, diverse antenna systems designed to eliminate “dead 

spots,” and an easy interface to existing network infrastructures.

The 802.11a standard defines data rates of 6, 12, 18, 24, 36 and 54 Mbps in the 5 GHz band. Demand 

for higher data rates may result in the need for devices that can communicate with each other at the 

higher rates, yet co-exist in the same WLAN environment or area without significant interference or 

interruption from each other, regardless of whether the higher data rate devices can communicate 

with the 802.11a devices. It may further be desired that high data rate devices be able to communicate 

with the 802.11a devices, such as at any of the standard 802.11a rates.

See, e.g., Shearer at 1:31-2:5.

One embodiment of a transmitter for an 802.11 device is provided in FIG. 3. Referring to FIG. 3, a 

PHY unit 300 includes an orthogonal frequency division multiplex (OFDM) transmit kernel 320, a 

symbol wave shaper/interpolator/shifter/summer(accumulator, assimilator) 310, an IQ modulator 312, 

a mixer 314, high power amplifier (HPA) 316, and antenna 318. OFDM transmit kernel 320 includes 

an FEC coder 302 (for encoding the data received from a MAC unit), an interleaver/mapper 304, an 

inverse fast Fourier transform (IFFT) unit 306, and cyclic extension logic 308.

During a data transmit process, data and control information are received at the FEC coder 302. The 

FEC coder 302 encodes data in a forward error correction code. Any forward error correction (FEC) 

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code can be used for this purpose. FEC code examples include a Reed-Solomon and a combination 

Reed-Solomon and convolution code, among others. The interleaver/mapper 304 subsequently 

interleaves (reorders, distributes) the encoded data. The output of the interleaver/mapper 304 is sent 

to the IFFT unit 306. The IFFT unit 306 receives input from the interleaver/mapper 304 and provides 

OFDM symbols to the cyclic extension logic 308. The cyclic extension logic 308 inserts a cyclic 

prefix (e.g., guard interval) to ensure that the transmitted symbol retains its orthogonal properties in 

the presence of multi-path delay spread. The output of the cyclic extension logic 308 is sent to the 

symbol wave shaper/interpolator/shifter/summer 310. Symbol wave 

shaper/interpolator/shifter/summer 310 comprises a low-pass filter to smooth the spectral edges 

between successive OFDM symbols. The trailing edge and leading edge of each OFDM symbol is 

tapered to prevent spectral splattering outside the frequency channel, minimizing adjacent 

interference and satisfying regulatory concerns. The symbol wave shaper/interpolator/shifter/summer 

310 also comprises interpolation, shifting, and summing functionality as described below.

See, e.g., Shearer at 4:62-5:29.

The output of symbol wave shaper/interpolator/shifter/summer 310 is sent to modulator 312. The 

modulator 312 modulates the encoded data onto carriers in OFDM symbols in accordance with 

conventional OFDM modulation techniques. The modulation techniques may be coherent or 

differential. The modulation mode or type may be Binary Phase Shift Keying and Quadrature Phase 

Shift Keying, among others.

The output of the modulator 312 is sent to mixer 314 where it is upconverted to the desired transmit 

frequency. The upconversion may be performed in multiple mixer stages. From mixer 314, the 

upconverted signal is amplified in high powered amplifier (HPA) 316 and sent to antenna 318 for 

transmission.

In an IEEE 802.11a/g design, each transmission channel has a bandwidth of 20 MHz. As shown in 

FIG. 4, in an IEEE 802.11a or IEEE 802.11g OFDM signal, a packet 400 within each 20 MHz 

channel has fifty-two (52) subcarriers. A first method of increasing the transmission data rate 

involves a variation in the waveform structure, or the subcarrier structure. In this section of the 

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discussion, the IEEE 802.11 a/g system will be referred to as an example legacy system. With IEEE 

802.11a/g, as a nonlimiting example, there are sixty-four (64) subcarriers bins from −10 MHz 402 to 

+10 MHz 404 because a 64 point IFFT is used. However, only 52 of the bins are populated with nonzero subcarriers. Twenty-six (26) active subcarriers are spectrally less than zero (DC), and 26 active 

subcarriers are spectrally greater than zero. There are five unused subcarriers on each spectral edge, 

forming edge gaps at the −10 MHz 402 and +10 MHz 404 points. In this nonlimiting example, the 

packet is 20 MHz wide because that is the span of the 64 points in the IFFT. Also, the 20 MHz (wide) 

packets are spaced in channels whose center frequencies are separated by 20 MHz. In a 20 MHz 

packet, the active (populated) subcarriers span a spectrum somewhat less than 20 MHz wide, about 

16.5 MHz, in this nonlimiting example.

As provided in FIG. 5, to increase the data rate, the legacy waveform 400 is modified and then, as 

described in detail later, the data rate can be further increased by extrapolating to 40 MHz. The 

modification of the legacy packet 400 includes adding two sets 502, 504 of two subcarriers to each 

packet 400 for a total of four added subcarriers 502, 504. Note that, for simplification, all 52 

subcarriers from the legacy waveform are not shown in FIG. 5. Also, although this discussion focuses 

on adding a total of four subcarriers, this disclosure should not be considered to be limited to a foursubcarrier addition. The four-subcarrier addition is an example used for simplification. The packet 

that had 52 subcarriers now has 56 subcarriers for each 20 MHz packet. A legacy packet uses 52 

subcarriers; in the improved system, a packet uses 56 subcarriers.

See, e.g., Shearer at 5:30-6:12.

To further increase the bandwidth of the signal, a processor (not shown) in the PHY 102 (FIG. 1) can 

further manipulate the OFDM signal. This discussion will focus on a scenario with two inputs, 

increasing the bandwidth by a factor of 2. However, the approach is applicable to any number of 

substantially simultaneous inputs. In one embodiment of an 802.11n system, two 20 MHz 802.11a 

input signals are received at the PHY unit 300 from FIG. 3 substantially simultaneously. The two 

signals are processed separately, one in a lower 20 MHz path and one in an upper 20 MHz path. A 

lower 20 MHz path 800 is presented in FIG. 8 and includes lower 20 MHz OFDM transmit kernel 

320 a, interpolator 310 a, and −10 MHz frequency shifter 310 b. One of the inputs is first processed 

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by the lower 20 MHz OFDM transmit kernel 320 a which corresponds to the transmit kernel 320 

from FIG. 3. The lower 20 MHz OFDM transmit kernel 320 a sends the signal to an interpolation 

stage 310 a where the signal is interpolated by a factor of the number of signals received substantially 

simultaneously. Interpolation stage 310 a corresponds to shaper/interpolator/shifter/summer 310 of 

FIG. 3. In this exemplary embodiment, two signals are received, so the interpolation factor is 2.

The interpolation stage 310 a increases the sample rate of the signal. If the signal is interpolated by 2, 

the sample rate is doubled. Interpolation can be performed by inserting zeros (i.e. zero stuffing) 

between the original samples. Then, this zero-stuffed sample stream is low-pass filtered (e.g. 

in symbol shaper 310 of FIG. 3). The low-pass filter is designed so the original spectrum is 

maintained, and only the bandwidth is doubled. This zero-stuffed example is but one method of 

interpolation. Another method would be to duplicate each individual sample. Other methods known 

to one of ordinary skill in the art would also apply. The output of interpolation stage 310 a is then 

shifted down by 10 MHz at frequency shift stage 310 b. Frequency shift stage 310 b corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. The frequency shift is performed by multiplying 

the sample by ej2Πf shift t, where fshift is the amount of desired frequency shift.

FIG. 9 presents an exemplary 20 MHz 802.11a OFDM signal 900 centered at center frequency fc. 

Note that each individual subcarrier is not shown in each drawing. After being processed in the 

interpolation stage 310 a (FIG. 8) and the frequency shift stage 310 b, the resulting 40 MHz down -

shifted signal 1000 is formed, as presented in FIG. 10.

An upper 20 MHz path 1100 is presented in FIG. 11, and comprises upper 20 MHz OFDM 

transmit kernel 320 b, interpolator 310 c, and +10 MHz frequency shifter 310 d. One of the inputs is 

first processed by the upper 20 MHz OFDM transmit kernel 320 b which corresponds to the 

transmit kernel 320 from FIG. 3. The upper 20 MHz OFDM transmit kernel 320 b sends the signal to 

an interpolation stage 310 c where the signal is interpolated by a factor of the number of signals 

received substantially simultaneously. Interpolation stage 310 c corresponds to 

shaper/interpolator/shifter/summer 310 of FIG. 3. In this exemplary embodiment, two signals are 

received, so the interpolation factor is 2. The output of interpolation stage 310 c is then shifted up by 

10 MHz at frequency shift stage 310 d. Frequency shift stage 310 d corresponds to 

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shaper/interpolator/shifter 310 of FIG. 3. The frequency shift is performed by multiplying the sample 

by ej2Πf shift t, where fshift is the amount of desired frequency shift.

An exemplary 20 MHz 802.11a OFDM signal 900 (as provided in FIG. 9), centered at center 

frequency fc, is processed in the interpolation stage 310 c and the frequency shift stage 310 d. The 

resulting 40 MHz up-shifted signal 1200 is formed, as presented in FIG. 12.

FIG. 13 presents an exemplary embodiment with 2 signal paths, upper path 1100 and lower path 800, 

each processing a 20 MHz 802.11a input signal substantially simultaneously. The output of each path 

is aggregated in adder 310 e to achieve, in this exemplary embodiment, a signal 1400 with a 40 MHz 

bandwidth and a 40 MHz sample rate as shown in FIG. 14. As provided above, this process could be 

easily adapted for other systems with different protocols, with different frequencies, and with more 

input signals.

See, e.g., Shearer at 8:17-9:24.

For a system with “x” number of input signals with substantially similar bandwidths and cen ter 

frequencies, received substantially simultaneously, the interpolation stage is performed by 

interpolating by a factor equal to “x.” In the shifting stage, the method is dependent on whether “x” is 

odd or even.

If “x” is even, each signal is shifted from the center frequency by a succeeding multiple of the 

bandwidth (BW) of the signal. For example, as illustrated in FIG. 15, if six 10 MHz signals (A, B, C, 

D, E, and F) are received, each is interpolated by a factor of six (6) in blocks 1500 a-1500 f. Each 

signal with a 10 MHz sample rate is interpolated such that each has a revised sample rate of 60 MHz. 

Then, in block 1502, signal A is shifted up by the BW/2. In block 1504, signal B is shifted down by 

BW/2. In block 1506, signal C is shifted up by 3*BW/2. In block 1508, signal D is shifted down by 

3*BW/2. In block 1510, signal E is shifted up by 5*BW/2. In block 1512, signal F is shifted down by 

5*BW/2. In block 1514, the six shifted signals are aggregated into one composite signal for 

transmission. This process is applicable for any even number of input signals. Each simultaneous 

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input is interpolated and shifted from the center frequency by a progressive odd multiple of BW/2 on 

alternating sides of the center frequency.

FIG. 16 demonstrates how an even number of signals are distributed from the center frequency. 

Signal A 1602 is shifted up by BW/2, signal B 1604 is shifted down by BW/2, signal C 1606 is 

shifted up by 3*BW/2, signal D 1608 is shifted down by 3*BW/2, signal E 1610 is shifted up by 

5*BW/2, and signal F 1612 is shifted down by 5*BW/2.

See, e.g., Shearer at 9:25-54.

Furthermore, this claim element is obvious in light of Shearer itself, when combined with any of the 

other references as charted for this claim element in Exs. A-1–A-31, First Supplemental Ex. AObviousness Chart, and/or when combined with the knowledge of one of ordinary skill in the art. 

Motivations to combine may come from the knowledge of the person of ordinary skill themselves, or 

from the known problems and predictable solutions as embodied in these references. Further 

motivations to combine references and additional details may be found in the Cover Pleading and 

First Supplemental Ex. A-Obviousness Chart.

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