Source: http://www.google.com/patents/US7852812?dq=4484186
Timestamp: 2016-08-27 12:00:06
Document Index: 16170594

Matched Legal Cases: ['art 11', 'art 11', 'art 11', 'art 11', 'Application No. 2009', 'Application No. 2002', 'Application No. 2003']

Patent US7852812 - Communication system using OFDM for one direction and DSSS for another direction - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsA method and apparatus for wireless communication are described. In one embodiment, a method for communicating with a subscriber comprises transmitting orthogonal frequency domain multiplexing (OFDM) signals to the subscriber, and receiving direct-sequence spread spectrum (DSSS) signals from the sub...http://www.google.com/patents/US7852812?utm_source=gb-gplus-sharePatent US7852812 - Communication system using OFDM for one direction and DSSS for another directionAdvanced Patent SearchPublication numberUS7852812 B2Publication typeGrantApplication numberUS 11/199,793Publication dateDec 14, 2010Filing dateAug 9, 2005Priority dateMar 9, 2001Fee statusLapsedAlso published asCN1507708A, CN100370710C, CN101083651A, US6940827, US8040855, US8873516, US20020159422, US20060067278, US20070223406, US20110032921, WO2002073831A1Publication number11199793, 199793, US 7852812 B2, US 7852812B2, US-B2-7852812, US7852812 B2, US7852812B2InventorsXiaodong Li, Hui Liu, Wenzhong ZhangOriginal AssigneeAdaptix, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (82), Non-Patent Citations (26), Referenced by (6), Classifications (27), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetCommunication system using OFDM for one direction and DSSS for another direction
US 7852812 B2Abstract
transmitting orthogonal frequency division multiplexing (OFDM) signals, the OFDM signals comprising OFDM modulation according to an OFDM only modulation technique;
receiving a direct-sequence spread spectrum (DSSS) signal generated by a subscriber, the DSSS signal comprising DSSS modulation according to a DSSS only modulation technique; and
enabling use of a first portion of OFDM subcarriers of said OFDM signals by the subscriber using said received DSSS signal.
2. The method of claim 1, wherein said receiving said DSSS signal comprises:
establishing a bi-directional DSSS communication link with the subscriber.
establishing a uni-directional OFDM communication link using said first portion of OFDM subcarriers.
4. The method of claim 3, wherein said bi-directional DSSS communication link and said uni-directional OFDM communication link comprise a same communication service.
5. The method of claim 1, wherein said enabling use of said first portion of said OFDM subcarriers comprises:
transmitting a signal to the subscriber.
establishing a bi-directional direct-sequence spread spectrum (DSSS) communication link with a subscriber, DSSS signals of the DSSS communication link comprising DSSS modulation according to a DSSS only modulation technique; and
enabling use of at least a portion of said OFDM signals by the subscriber using communication via said bi-directional DSSS communication link, wherein said use of said at least a portion of said OFDM signals provides a uni-directional OFDM link.
7. The method of claim 6, wherein said bi-directional DSSS communication link and said uni-directional OFDM link comprise a same communication service.
transmitting signals for controlling said bi-directional DSSS communication link as DSSS signals in said bi-directional DSSS communication link; and
transmitting signals for controlling said uni-directional OFDM communication link as OFDM signals in said uni-directional OFDM communication link.
9. The method of claim 6, wherein said bi-directional DSSS communication link comprises a frequency division duplex (FDD) communication link, and wherein said uni-directional OFDM communication link occupies different spectrum than said DSSS communication link.
establishing a bi-directional direct-sequence spread spectrum (DSSS) communication link with a subscriber, wherein DSSS signals of the DSSS communication link comprise DSSS modulation according to a DSSS only modulation technique; and
establishing a uni-directional orthogonal frequency division multiplexing (OFDM) link with the subscriber, wherein OFDM signals of the OFDM communication link comprise OFDM modulation according to an OFDM only modulation technique, and wherein said bi-directional DSSS communication link and said uni-directional communication link are part of a same communication service.
11. The method of claim 10, wherein said establishing said uni-directional OFDM link comprises:
enabling use of at least a portion of transmitted OFDM signals by the subscriber using communication via said bi-directional DSSS communication link.
establishing a bi-directional DSSS communication link between a subscriber and a base station, wherein DSSS signals of the DSSS communication link comprise DSSS modulation according to a DSSS only modulation technique;
using said bi-directional DSSS communication link to communicate information for use in establishing an orthogonal frequency division multiplexing (OFDM) communication link for use by the subscriber; and
establishing a uni-directional OFDM communication link with the subscriber using said DSSS communication link, wherein OFDM signals of the OFDM communication link comprise OFDM modulation according to an OFDM only modulation technique.
14. The method of claim 13, wherein said bi-directional DSSS communication link and said uni-directional OFDM link comprise a same communication service.
15. The method of claim 13, wherein said establishing said uni-directional OFDM link comprises:
a subscriber having
a DSSS transmitter,
a DSSS receiver; and
an OFDM receiver;
a communication network communicably coupled with the subscriber, the communication network having
a DSSS receiver,
a DSSS transmitter; and
an OFDM transmitter, and
a communication service protocol operable to establish a bi-directional communication link for use by the subscriber using said DSSS transmitters and DSSS receivers and a uni-directional communication link for use by the subscriber using said OFDM receiver and OFDM transmitter, wherein DSSS signals of the DSSS communication link comprise DSSS modulation according to a DSSS only modulation technique, and wherein OFDM signals of the OFDM communication link comprise OFDM modulation according to an OFDM only modulation technique.
transmitting orthogonal frequency division multiplexing (OFDM) signals;
receiving a plurality of direct-sequence spread spectrum (DSSS) signals generated by a plurality of subscribers, wherein the plurality of DSSS signals are transmitted asynchronously; and
enabling use of a first portion of OFDM subcarriers of said OFDM signals by the subscribers using a respective DSSS signal of said received DSSS signals. Description
This is a continuing application of application Ser. No. 09/802,453, entitled “COMMUNICATION SYSTEM USING OFDM FOR ONE DIRECTION AND DSSS FOR ANOTHER DIRECTION,” filed Mar. 9, 2001, the disclosure of which is hereby incorporated herein by reference thereto.
Due to the asymmetric nature of packet traffic, the requirements for wireless uplink (from subscribers to base-stations or access points) and downlink (from base-stations or access points to subscribers) are quite different. High throughput/spectral efficiency is of paramount importance in the traffic-heavy downlink, even if it means more involved hardware and higher cost power amplifiers at the base-station. On the other hand, amplifier efficient modulation schemes are critical to the subscriber terminal, in order to reduce cost and improve power efficiency. Clearly, separate design optimization approaches must be adopted for the design of uplink and downlink modems. However almost all current systems, e.g., the popular GSM and IS-95 networks, utilize a uniform modem and multiple-access structure or both uplink and downlink. As a result, the efficiency of the overall system is compromised.
OFDM is an efficient technique for multipath fading channels. In a well-designed system, the frequency response of each subcarrier can be made flat or near flat. Therefore, only very simple or even no channel equalization is required. Another significant advantage of OFDM is that it allows an optimal power and rate allocation to maximize the channel capacity. This inherent advantage is even more significant in a cellular system with multiple subscribers where the channel response of each subscriber is different. In this case, it is possible to maximize the entire system capacity throughput by judicious allocations of subcarriers to multiple subscribers.
On the other hand, OFDM also possesses some disadvantages. One of the disadvantages is the large peak-to-average power (PAP) ratio of the OFDM signals. This is a significant hurdle for implementing OFDM-based systems. A large PAP ratio means more stringent linearity requirements on the power amplifier or large back off, leading to higher cost or lower transmission power. This is especially undesirable for the implementation of subscriber terminals, which dominates the system cost due to their large quantity. In addition, to achieve the maximum capacity of OFDM with adaptive subcarrier allocation, it is often required to feedback the channel measurement at the subscribers to the base station. This can also add overhead and complicate the system control.
FIG. 6 is a block diagram of one embodiment of a subscriber terminal transmitter that uses DSSS/CDMA for uplink communications.
FIG. 11 is a block diagram of one embodiment of a duplexing system using CDMA for bi-directional transmission and an additional OFDM channel, to enhance the data rate of one direction.
The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general purpose systems may be used with programs in accordance with the teachings herein; or it may prove convenient to construct more specialized apparatus to perform the required method steps. The required structure for a variety of these systems will appear from the description below. In addition, the present invention is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the invention as described herein.
In one embodiment, the subcarriers of the OFDM downlink are adaptively allocated to multiple subscribers to achieve multiplexing and to increase (and potentially maximize) the system capacity. Information extracted from uplink CDMA signals received at the base station from the multiple subscribers may be utilized for the adaptive subcarrier allocation. This is described in more detail below.
In one embodiment, the downlink SNR for each subcarrier is measured by the subscriber. The information is fed back to the base station subcarrier allocator, which collects the SINR information from all subscribers. The subcarrier allocator can then perform optimal or suboptimal allocating algorithms to assign the subcarriers with relatively high SNR to a subscriber. In another embodiment, as described below, the SNR information is directly derived from the uplink signals sent by each subscriber. These two techniques are described in further detail below. The two techniques of collecting the SNR information can also be combined. For example, the two could be combined by using a weighted average of the two. Alternatively, the combination could be based on time where either operates at different times and not continuously, and the SNR information resulting from both are used.
In one embodiment, the received signals are sampled sequentially in time, with the samples being stored in memory. Once a predetermined number of samples have been received (e.g., 512 samples), serial-to-parallel connector 506 converts the incoming OFDM signal (in the form of samples) into a parallel form in a manner well-known in the art. The outputs of serial-to-parallel converter 506 are received by inputs of Fast Fourier Transform (FFT) 505, which applies a Fast Fourier Transform in a manner well-known in the art. The outputs of FFT 505 are sent to one of a number of different paths. That is, these outputs of FFT 505 are coupled to multiple processing paths labeled 1-n.
A demultiplexer (Demux) 507, which may be part of a media access control (MAC) layer, demultiplexes the output from FEC decoders 502 1-n from multiple subcarriers, where the user data is on clusters of subcarriers, to create user data 501 1-n.
Note that in a software implementation of the receiver in which the processing block of FIG. 5 are implemented in software, signals received using the antenna are sampled and the samples are stored in a memory for processing by the processing blocks.
In another embodiment, the channel frequency response associate with a subscriber is estimated based on the uplink spreading spectrum signals without the use of training sequences or pilot signals. The frequency response is estimated to within a phase ambiguity, and the amplitude response is utilized in subcarrier allocations.
In another embodiment, CDMA is used for downlink and uplink transmission. To further enhance the data rate of downlink, an additional OFDM channel is used as shown in FIG. 11. Referring to FIG. 11, two communications systems (e.g., communication units, stations, etc.) are shown in the duplexing system. Communication system 1150 comprises CDMA transmitter 1101, CDMA receiver 1102, and OFDM receiver 1103 coupled to antenna 1105 via switch or duplexer 1104. Similarly, communication system 1151 comprises a CDMA receiver 1108, CDMA transmitter 1110, and OFDM transmitter 1109 coupled to antenna 1106 via switch or duplexer 1107.
In one embodiment, CDMA transmitter and receiver pairs in each of the communication systems are implemented as a CDMA transceiver. In one embodiment both systems include a CDMA transceiver and an OFDM transceiver, which comprises an OFDM transmitter and OFDM receiver.
Referring to FIG. 13, each base station periodically broadcasts pilot OFDM symbols to every subscriber within its cell (or sector) (processing block 101). The pilot symbols, often referred to as a sounding sequence or signal, are known to both the base station and the subscribers. In one embodiment, each pilot symbol covers the entire OFDM frequency bandwidth. The pilot symbols may be different for different cells (or sectors). The pilot symbols can serve multiple purposes: time and frequency synchronization; channel estimation and signal-to-interference/noise (SINR) ratio measurement for cluster allocation.
Next, each subscriber continuously monitors the reception of the pilot symbols and measures the SINR and/or other parameters, including inter-cell interference and intra-cell traffic, of each cluster (processing block 1302). Based on this information, each subscriber selects one or more clusters with good performance (e.g., high SINR and low traffic loading) relative to each other and feeds back the information on these candidate clusters to the base station through redefined uplink access channels (processing block 1303). For example, SINR values higher than 10 dB may indicate good performance. Likewise, a cluster utilization factor less than 50% may be indicative of good performance. Each subscriber selects the clusters with relatively better performance than others. The selection results in each subscriber selecting clusters they would prefer to use based on the measured parameters.
From time to time, processing logic performs retraining by repeating the process described above (processing block 1306). The retaining may be performed periodically. This retraining compensates for subscriber movement and any changes in interference. In one embodiment, each subscriber reports to the base station its updated selection of clusters and their associated SINRs. Then the base station further performs the reselection and informs the subscriber about the new cluster allocation. Retraining can be initiated by the base station, and in which case, the base station requests a specific subscriber to report its updated cluster selection. Retraining can also be initiated by the subscriber when it observes channel deterioration.
QPSK, 1/8 Spreading
In one embodiment, each base station transmits pilot symbols simultaneously, and each pilot symbol occupies the entire OFDM frequency bandwidth, as shown in FIGS. 14A-C. Referring to FIG. 14A-C, pilot symbols 1401 are shown traversing the entire OFDM frequency bandwidth for cells A, B and C, respectively. In one embodiment, each of the pilot symbols have a length or duration of 128 microseconds with a guard time, the combination of which is approximately 152 microseconds. After each pilot period, there are a predetermined number of data periods followed by another set of pilot symbols. In one embodiment, there are four data periods used to transmit data after each pilot, and each of the data periods is 152 microseconds.
FIG. 15 illustrates one embodiment of subscriber processing. The processing is performed by processing logic that may comprise hardware (e.g., dedicated logic, circuitry, etc.), software (such as that which runs on, for example, a general purpose computer system or dedicated machine), or a combination of both.
FIG. 16 is one embodiment of an apparatus for the selection of clusters based or power difference. The approach uses information available during both pilot symbol periods and data traffic periods to perform energy detection. The processing of FIG. 16 may be implemented in hardware, (e.g., dedicated logic, circuitry, etc.), software (such as is run on, for example, a general purpose computer system or dedicated machine), or a combination of both.
P P =P S +P I +P N,
P D = { P N , with no signal and interference P S + P N , with signal only P I + P N , with interference only P S + P I + P N , with both signal and interference P P - P D = { P S + P I , with no signal and interference P I , with signal only P S , with interference only O , with both signal and interference where PP is the measured power corresponding to each cluster during pilot periods, PD is the measured power during the traffic periods, PS is the signal power, PI is the interference power, and PN is the noise power.
In one embodiment, the subscriber selects clusters with relatively large PP/(PP−PD) (e.g., larger than a threshold such as 10 dB) and avoids clusters with low PP|(PP−PD) (e.g., lower than a threshold such as 10 dB) when possible.
Alternatively, the difference may be based on the energy difference between observed samples during the pilot period and during the data traffic period for: each of the subcarriers in a cluster such as the following:
Δ i =  y i P  -  y i D  Thus, the subscriber sums the differences for all subcarriers.
β=f(SINR, P P/(P P −P D)
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5434572Jun 7, 1994Jul 18, 1995Ramtron International CorporationSystem and method for initiating communications between a controller and a selected subset of multiple transponders in a common RF fieldUS5479447May 3, 1993Dec 26, 1995The Board Of Trustees Of The Leland Stanford, Junior UniversityMethod and apparatus for adaptive, variable bandwidth, high-speed data transmission of a multicarrier signal over digital subscriber linesUS5504775Feb 2, 1994Apr 2, 1996U.S. Philips CorporationMulti-user spread spectrum communication systemUS5515378Dec 12, 1991May 7, 1996Arraycomm, Inc.Spatial division multiple access wireless communication systemsUS5555268Jan 24, 1994Sep 10, 1996Fattouche; MichelMulticode direct sequence spread spectrumUS5640413Jan 21, 1994Jun 17, 1997Nec CorporationDigital mobile radio communication systemUS5708973Jul 27, 1994Jan 13, 1998Siemens AktiengesellschaftRadio system with frequency optimizationUS5726978Jun 22, 1995Mar 10, 1998Telefonaktiebolaget L M Ericsson Publ.Adaptive channel allocation in a frequency division multiplexed systemUS5734967Dec 20, 1995Mar 31, 1998Motorola, Inc.Method and apparatus for reducing self interference in a communication systemUS5825812 *Jun 6, 1996Oct 20, 1998Wireless Logic, Inc.Suppressed side lobe direct-sequence-spread-spectrum radio communication method and deviceUS5886988Dec 31, 1996Mar 23, 1999Arraycomm, Inc.Channel assignment and call admission control for spatial division multiple access communication systemsUS5887245Jun 17, 1996Mar 23, 1999Telefonaktiebolaget Lm EricssonMethod and apparatus for regulating transmission powerUS5914933Oct 15, 1996Jun 22, 1999Lucent Technologies Inc.Clustered OFDM communication systemUS5933421Feb 6, 1997Aug 3, 1999At&T Wireless Services Inc.Method for frequency division duplex communicationsUS5956642Nov 25, 1996Sep 21, 1999Telefonaktiebolaget L M EricssonAdaptive channel allocation method and apparatus for multi-slot, multi-carrier communication systemUS5961603 *Sep 22, 1997Oct 5, 1999Worldgate Communications, Inc.Access system and method for providing interactive access to an information source through a networked distribution systemUS5973642Apr 1, 1998Oct 26, 1999At&T Corp.Adaptive antenna arrays for orthogonal frequency division multiplexing systems with co-channel interferenceUS5991273May 1, 1997Nov 23, 1999Nortel Networks CorporationDetermining SINR in a communications systemUS6005876Sep 24, 1996Dec 21, 1999At&T CorpMethod and apparatus for mobile data communicationUS6026123Aug 2, 1997Feb 15, 2000Williams; Thomas H.Digital transmission system with high immunity to dynamic linear distortionUS6041237Apr 2, 1998Mar 21, 2000Siemens AktinegesellschaftMethod of channel allocationUS6052594Apr 30, 1997Apr 18, 2000At&T Corp.System and method for dynamically assigning channels for wireless packet communicationsUS6061568Oct 1, 1996May 9, 2000Ericsson Inc.Method and apparatus for mitigating intermodulation effects in multiple-signal transmission systemsUS6064692Jun 20, 1997May 16, 2000Amati Communications CorporationProtocol for transceiver initializationUS6064694Sep 30, 1997May 16, 2000The Aerospace CorporationFrequency translating device transmission response systemUS6067290Jul 30, 1999May 23, 2000Gigabit Wireless, Inc.Spatial multiplexing in a cellular networkUS6084871Nov 21, 1995Jul 4, 2000Telia AbMethod for synchronization of transmitter and receiver at mobile radio systemUS6108374Aug 25, 1997Aug 22, 2000Lucent Technologies, Inc.System and method for measuring channel quality informationUS6131016Aug 27, 1997Oct 10, 2000At&T CorpMethod and apparatus for enhancing communication reception at a wireless communication terminalUS6144696Dec 31, 1997Nov 7, 2000At&T Corp.Spread spectrum bit allocation algorithmUS6175550Apr 1, 1997Jan 16, 2001Lucent Technologies, Inc.Orthogonal frequency division multiplexing system with dynamically scalable operating parameters and method thereofUS6175555Jun 11, 1998Jan 16, 2001At&T Wireless Svcs. Inc.Transmit/receive compensationUS6226320May 7, 1996May 1, 2001Nokia Telecommunications OyMethod and equipment for multirate coding and detection in a multiple access mobile communication systemUS6282683 *Sep 15, 1999Aug 28, 2001Adc Telecommunications, Inc.Communication system with multicarrier telephony transportUS6320897Sep 3, 1999Nov 20, 2001Wi-Lan Inc.Multicode spread spectrum communications systemUS6359923Dec 18, 1997Mar 19, 2002At&T Wireless Services, Inc.Highly bandwidth efficient communicationsUS6366195Mar 13, 1998Apr 2, 2002Wireless Online, Inc.Power control in two-way paging systemsUS6373861Dec 1, 1999Apr 16, 2002Samsung Electronics Co, Ltd.Frequency synchronizing device for OFDM/CDMA systemUS6377632Jan 24, 2000Apr 23, 2002Iospan Wireless, Inc.Wireless communication system and method using stochastic space-time/frequency division multiplexingUS6377782 *Feb 15, 2000Apr 23, 2002Mediacell, Inc.Method and apparatus for communicating between a client device and a linear broadband networkUS6407993Apr 30, 1998Jun 18, 2002Koninklije Philips Electronics N.V.Flexible two-way telecommunication systemUS6449630Apr 7, 1999Sep 10, 2002Mitsubishi Electric Research Laboratories, Inc.Multiple function processing core for communication signalsUS6477158Sep 18, 1998Nov 5, 2002Mitsubishi Denki Kabushiki KaishaMethod and apparatus for assigning codesUS6480521Mar 26, 1997Nov 12, 2002Qualcomm IncorporatedMethod and apparatus for transmitting high speed data in a spread spectrum communications systemUS6665348Aug 9, 1999Dec 16, 2003Kamilo FeherSystem and method for interoperable multiple-standard modulation and code selectable Feher's GMSK, enhanced GSM, CSMA, TDMA, OFDM, and third-generation CDMA, W-CDMA and B-CDMAUS6940827Mar 9, 2001Sep 6, 2005Adaptix, Inc.Communication system using OFDM for one direction and DSSS for another directionUS7133352Sep 20, 1999Nov 7, 2006Zion HadadBi-directional communication channelUS20020026645 *Jan 29, 2001Feb 28, 2002Diva Systems Corp.Method and apparatus for content distribution via non-homogeneous access networksUS20020111187 *Mar 5, 1999Aug 15, 2002Hiroshi HaradaMulti-mode radio transmission systemUS20030067890Oct 10, 2001Apr 10, 2003Sandesh GoelSystem and method for providing automatic re-transmission of wirelessly transmitted informationUS20030104816 *Feb 1, 2001Jun 5, 2003Philippe DuplessisDual band unidirectional scheme in a cellular mobile radio telecommunications systemUS20030147655Feb 7, 2003Aug 7, 2003Shattil Steve J.Unified multi-carrier framework for multiple-access technologiesUS20030169824Mar 8, 2002Sep 11, 2003Naftali ChayatOrthogonal division multiple access technique incorporating single carrier and OFDM signalsUS20030231728Mar 25, 2003Dec 18, 2003Oki Techno Centre (Singapore) Pte Ltd.Frequency estimation in a burst radio receiverUS20040042385Apr 23, 2003Mar 4, 2004Ki-Yun KimPreamble design for frequency offset estimation and channel equalization in burst OFDM transmission systemUS20050025042 *Aug 20, 2004Feb 3, 2005Zion HadadBi-directional communication channelUS20050201268Mar 10, 2005Sep 15, 2005Tsuguhide AokiOFDM signal transmission method and apparatusUS20060176802Jan 20, 2006Aug 10, 2006Samsung Electronics Co., Ltd.Apparatus and method for compensating for frequency offset in wireless communication systemUS20070025319Sep 29, 2006Feb 1, 2007Roberto PadovaniMethod and apparatus for high rate packet data transmissionUS20070297382Sep 4, 2007Dec 27, 2007Conexant Systems, Inc.Dual Packet Configuration for Wireless CommunicationsCN101202725ADec 11, 2006Jun 18, 2008昂达博思公司Auto frequency offset compensation in TDD wireless OFDM communication systemDE19800953C1Jan 13, 1998Jul 29, 1999Siemens AgResource allocation in radio interface of radio communications systemEP0869647A2Mar 24, 1998Oct 7, 1998Lucent Technologies Inc.System of multicarreir modulation with dynamically scalable operating parametersEP0926912A2Nov 3, 1998Jun 30, 1999CSELT Centro Studi e Laboratori Telecomunicazioni S.p.A.Method for channel assignment in a mobile communication system with space division multiple accessEP0929202A1Dec 4, 1998Jul 14, 1999Lucent Technologies Inc.Uplink channel allocation for a mobile cellular networkFR2777407A1 Title not availableGB2209858A Title not availableJP2000236284A Title not availableJP2001007883A Title not availableJPH0621860A Title not availableJPH0629922A Title not availableJPH06224835A Title not availableJPH07183862A Title not availableJPH07254915A Title not availableJPH10210002A Title not availableJPH10224323A Title not availableKR20010005661A Title not availableWO1998016077A2Oct 10, 1997Apr 16, 1998Teratech CorporationCommunication system using geographic position dataWO1998030047A1Dec 30, 1997Jul 9, 1998Arraycomm, Inc.Channel assignment and call admission control for spatial division multiple access communication systemsWO1998051111A1Mar 12, 1998Nov 12, 1998Koninklijke Philips Electronics N.V.Link quality dependent modulation schemeWO2000054445A1Mar 10, 2000Sep 14, 2000Sony CorporationDigital broadcast receiverWO2002049305A2Dec 13, 2001Jun 20, 2002Broadstorm Telecommunications, Inc.Ofdma with adaptive subcarrier-cluster configuration and selective loading* Cited by examinerNon-Patent CitationsReference1ANSI/EEE Std 802.11, 1999 Edition Part 11: Wireless LAN Meduim Access Control (MAC) and Physical Layer (PHY) Specifications, Published Aug. 20, 1999, The IEEE, Inc. 3 Park Avenue, NY, NY 10016, 528 pgs.2Armstrong, J., "Analysis of new and existing methods of reducing intercarrier interference due to carrier frequency offset in OFDM", IEEE Transactions on communications, vol. 47, No. 3, Mar. 1999, pp. 365-369.3Bender et al., "CDMA/HDR: A Bandwidth-Efficient High-Speed Wireless Data Service for Nomadic Users", IEEE Communications Magazine, Jul. 2000, pp. 70-87.4Farsakh, C. et al., "Maximizing the SDMS Mobile Radio Capacity Increase by DOA Sensitive Channel Allocation", Wireless Personal Communications, Kluwer Academic Publishers, NL, vol. 11, No. 1, Oct. 1999, pp. 63-76, XP000835062, ISSN: 0929-6212.5Farsakh, C. et al., "Maximizing the SDMS Mobile Radio Capacity Increase by DOA Sensitive Channel Allocation", Wireless Personal Communications, Kluwer Academic Publishers, NL, vol. 11, No. 1, Oct. 1999, pp. 63-76, XP000835062, ISSN: 0929—6212.6Farsakh, Christof et al., On the Mobile Radio Capacity Increase Through SDMA, no date (after 1997).7Frollone et al., PRMA Performance in Cellular Environments with Self-Adaptive Channel Allocation Strategies, IEEE Transaction on Vehicular Technology, Nov. 1996, pp. 657-665, vol. 45, No. 4.8Grunheid, R. et al., "Adaptive Modulation and Multiple Access for the OFDM Transmission Technique", Wireless Personal Communications, Kluwer Academic Publishers, NL, vol. 13, Nr. 1/2 Year 2000, pp. 5-13, XP000894156 ISSN: 0929-6212.9 *IEEE Std 802.11a-1999 (R2003) Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications High-speed Physical Layer in the 5 GHz Band IEEE, 445 Hoes Lane, Piscataway, NJ 08855.10IEEE Std 802.11a-1999 (R2003), Part 11: Wireless LAN Medum Access Control (MAC) and Physical Layer (PHY) Specifications: High-speed Physical Layer in the 5 GHz Band, Published 1999, The IEEE, Inc., 3 Park Avenue , NY, NY 10016, 90 pgs.11 *IEEE Std 802.11b-1999 (R2003) Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications Higher-speed Physical Layer Extension in the 2.4 GHz Band IEEE, 445 Hoes Lane, Piscataway, NJ 08855.12International Search Report and Written Opinion issued for PCT/US2007/086340; Dated: May 1, 2008; 10 Pages.13Japanese Office Action with English translation issued for 2002-572752 dated Mar. 26, 2007.14Kapoor, S. et al., "Adaptive Interference Suppression in Multiuser Wireless OFDM Systems Using Antenna Arrays", IEEE Transactions on Signal Processing, vol. 47, No. 12, Dec. 1999, pp. 3381-3391, XP000935422, IEEE, New York, USA, ISSN: 1053-587X.15Kinugawa, Y. et al., "Frequency and Time Division Multiple Access with Demand-Assignment Using Multicarrier Modulation for Indoor Wireless Communications Systems", IEICE Transactions on Communications, Institute of Electronics Information and Comm. Eng. Tokyo, Japan, vol. E77-B, NR. 3, Mar. 1994, pp. 396-402, XP000451014, ISSN: 0916-8516.16Korean Intellectual Property office action issued for Korean Patent Application No. 2009-7017123, dated Sep. 28, 2009, with English translation, 9 pages.17Montegi, M. et al., "Optimum Band Allocation According to Subband Condition for BST-OFDM" 11th IEEE International Symposium on Personal Indoor and Mobile Radio Communications, vol. 2, Sep. 18-21, 2000, pp. 1236-1240, XP002213669, Piscataway, NJ, USA ISBN: 07803-6463-5.18Nogueroles, R. et al., "Improved Performance of a Random OFDMA Mobile Communication System", Vehiculadr Technology Conference, 1998, (May 18, 1998), pp. 2502-2506, XP010288120, ISBN: 0-7803-4320-4.19Office Action from Japanese Patent Application No. 2002-572752 dispatched on Jul. 31, 2006, Dispatch No. 327045.20Office action from Korean Patent Application No. 2003-7011937 dated Jan. 30, 2008, 3 ppgs.21Shad et al., Indoor SDMA Capacity Using s Smart Antenna Basestation, 1997 IEEE, pp. 868-872.22Tsoulos, G.V., "Smart Antennas for Mobile Communications Systems: Benefits and Challenges", Electronics & Communications Engineering Journal, Apr. 1999, pp. 84-94.23Ward, James et al., "High Throughput Slotted ALOHA Packet Radio Networks with Adaptive Arrays", IEEE Transactions on Communications, Mar. 1993, pp. 460-470, vol. 41, No. 3.24Wong, C.Y., et al., Multiuser OFDM with Adaptive Subcarrier, Bit, and Power Allocation, IEEE, Journal on Selected Areas in Communications, Oct. 1999, IEEE Inc., New York, USA, vol. 17, Nr. 10, pp. 1747-1758, XP000854075, ISSN: 0733-8716 Sections I and II abstract.25Xu, Guanghan et al., "Throughput Multiplications of Wireless Lans for multimedia Servies: SDMA Protocol Design", 1994 IEEE, pp. 1326-1332.26Ye Li et al.: "Clustered OFDM with Channel Estimation for High Wireless Data", MObile Multimedia Communications, 199. (MOMUC '99). 1999 IEEE International Workshop on San Diego, CA, USA IEEE, US Nov. 15, 1999, pp. 43-50, XP010370695, ISBN: 0-7803-5904-6.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS8873516 *Oct 15, 2010Oct 28, 2014Adaptix, Inc.Communication system using OFDM for one direction and DSSS for another directionUS8917660 *May 23, 2011Dec 23, 2014Interdigital Technology CorporationMethod for performing wireless switchingUS20100067563 *Aug 25, 2006Mar 18, 2010Telefonaktiebolaget Lm Ericsson (Publ)Method and system of communicationsUS20110032921 *Feb 10, 2011Adaptix, Inc.Communication system using ofdm for one direction and dsss for another directionUS20110222617 *Sep 15, 2011Interdigital Technology CorporationMethod for performing wireless switchingUS20120044845 *Jun 13, 2011Feb 23, 2012Samsung Electronics Co. Ltd.Transmission power control method of base station in ofdma-based wireless communication system* Cited by examinerClassifications U.S. Classification370/335, 375/140International ClassificationH04L5/14, H04L5/02, H04B7/216, H04L27/26, H04J11/00, H04W16/10, H04W72/08, H04W52/10, H04W52/08, H04B1/707Cooperative ClassificationH04W52/08, H04L27/2601, H04L5/023, H04W16/10, H04W72/08, H04L5/14, H04W52/10, H04L5/143, H04B1/707European ClassificationH04L5/02Q, H04L27/26M, H04B1/707, H04L5/14P, H04L5/14, H04W16/10Legal EventsDateCodeEventDescriptionMar 3, 2006ASAssignmentOwner name: J & K SERVICES, L.L.C., WASHINGTONFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BROADSTORM TELECOMMUNICATIONS, INC., BY THEIR DULY AUTHORIZED OFFICER, VERNON L. FOTHERINGHAM;REEL/FRAME:017249/0092Effective date: 20040830Owner name: SDR HOLDINGS, L.L.C., WASHINGTONFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:J & K SERVICES L.L.C., BY THEIR DULY AUTHORIZED OFFICER, JOHN E. 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