Source: https://patents.google.com/patent/US8743837B2/en
Timestamp: 2019-07-17 03:54:57
Document Index: 642744

Matched Legal Cases: ['application No. 60', 'art 960', 'arts 960', 'application No. 200580049854', 'art 11', 'art 11']

US8743837B2 - Modified preamble structure for IEEE 802.11A extensions to allow for coexistence and interoperability between 802.11A devices and higher data rate, MIMO or otherwise extended devices - Google Patents
US8743837B2
US8743837B2 US12/552,705 US55270509A US8743837B2 US 8743837 B2 US8743837 B2 US 8743837B2 US 55270509 A US55270509 A US 55270509A US 8743837 B2 US8743837 B2 US 8743837B2
US12/552,705
US20100061402A1 (en
2005-05-27 Priority to US11/140,349 priority patent/US7599332B2/en
2009-09-02 Application filed by Qualcomm Inc filed Critical Qualcomm Inc
2009-09-02 Priority to US12/552,705 priority patent/US8743837B2/en
2009-09-02 Assigned to QUALCOMM INCORPORATED reassignment QUALCOMM INCORPORATED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: VAN NEE, D. J. RICHARD, VAN ZELST, ALBERT, JONES, VINCENT K.
2010-03-11 Publication of US20100061402A1 publication Critical patent/US20100061402A1/en
2014-06-03 Publication of US8743837B2 publication Critical patent/US8743837B2/en
The present application is a continuation of U.S. application Ser. No. 11/140,349, filed May 27, 2005, now allowed, entitled “MODIFIED PREAMBLE STRUCTURE FOR IEEE 802.11A EXTENSIONS TO ALLOW FOR COEXISTENCE AND INTEROPERABILITY BETWEEN 802.11A DEVICES AND HIGHER DATA RATE, MIMO OR OTHERWISE EXTENDED DEVICES”, which is a continuation-in-part of pending U.S. application Ser. No. 10/820,440, filed Apr. 5, 2004, entitled “MODIFIED PREAMBLE STRUCTURE FOR IEEE 802.11A EXTENSIONS TO ALLOW FOR COEXISTENCE AND INTEROPERABILITY BETWEEN 802.11A DEVICES AND HIGHER DATA RATE, MIMO OR OTHERWISE EXTENDED DEVICES”, the contents of which are incorporated by reference herein in their entirety.
The present application also claims benefit under 35 USC 119(e) of U.S. provisional application No. 60/575,608, filed May 27, 2004, entitled “MODIFIED PREAMBLE STRUCTURE FOR IEEE 802.11A EXTENSIONS AND DETECTING THE NUMBER OF TRANSMIT ANTENNAS IN MEMO OR MISO COMMUNICATION SYSTEMS”, the content of which is incorporated herein by reference in its entirety.
As can be seen from FIG. 1, the DC value and the 28th through 38th values, corresponding to the edges of the 20 MHz channel, are zero. The output of a transmitter is a training symbol at a sample rate of 64 samples symbol. The samples are obtained by taking a 64-point IFFT (inverse fast-Fourier transform) of the long training sequence. L1 in this example. As used herein, a sequence in the frequency domain is expressed with uppercase letters (e.g., L(k)), while the corresponding time sequence is expressed with lowercase letters (e.g., 1(k)).
A modified preamble can use the same structure as the 802.11a preamble, with a different long training symbol determined from a long training symbol sequence LD. By keeping the same short symbols S, or by applying cyclic shifts on S for the second, third, etc. transmit antennas, and using the same timing structure as depicted in FIG. 1, a receiver using the extended mode can use the same hardware for detecting the repetitive S and L symbols, even though the actual contents of the L symbols may be different for the 802.11a extensions.
∑ k = 0 31 ⁢ L 2 ⁡ ( 2 ⁢ k ) ⁢ L 3 ⁡ ( 2 ⁢ k ) = - 1 ( Equ . ⁢ 1 ) ∑ k = 0 31 ⁢ L 2 ⁡ ( 2 ⁢ k + 1 ) ⁢ L 3 ⁡ ( 2 ⁢ k + 1 ) = 0 ( Equ . ⁢ 2 )
r si ⁡ ( k ) = ∑ k = 0 63 ⁢ S i ⁡ ( k ) ⁢ L 2 ⁡ ( k ) ( Equ . ⁢ 3 ⁢ a ) r m ⁢ ⁢ i ⁡ ( k ) = ∑ k = 0 63 ⁢ S i ⁡ ( k ) ⁢ L 3 ⁡ ( k ) ( Equ . ⁢ 3 ⁢ b )
m s =  ∑ i = 0 N - 1 ⁢ ∑ k = 2 26 ⁢ [ r si ⁡ ( k ) ⁢ r si * ⁡ ( k - 1 ) + r si ⁡ ( k + 37 ) ⁢ r si * ⁡ ( k + 36 ) ]  ( Equ . ⁢ 4 ⁢ a ) m m =  ∑ i = 0 N - 1 ⁢ ∑ k = 0 11 ⁢ [ r m ⁢ ⁢ i ⁡ ( 2 ⁢ k + 3 ) ⁢ r m ⁢ ⁢ i * ⁡ ( 2 ⁢ k + 1 ) + r m ⁢ ⁢ i ⁡ ( 2 ⁢ k + 41 ) ⁢ r m ⁢ ⁢ i * ⁡ ( 2 ⁢ k + 39 ) + r m ⁢ ⁢ i ⁡ ( 2 ⁢ k + 4 ) ⁢ r m ⁢ ⁢ i * ⁡ ( 2 ⁢ k + 2 ) + r m ⁢ ⁢ i ⁡ ( 2 ⁢ k + 42 ) ⁢ r m ⁢ ⁢ i * ⁡ ( 2 ⁢ k + 40 ) ]  ( Equ . ⁢ 4 ⁢ b )
l ⁡ ( i ) = ∑ k = 0 63 ⁢ L ⁡ ( k ) ⁢ exp ⁡ ( j ⁢ 2 ⁢ π ⁢ ⁢ i ⁢ ⁢ k 64 ) ( Equ . ⁢ 5 )
In the extended modes described herein, some possible modifications will be described. First. L(k) can contain more than 52 non-zero subcarriers. Second, in the case of MIMO transmission. l(i) can have a cyclic shift that may be different for each transmitter. The shifted signal lk(i) can be derived from l(i) as lk(i)=l([i+64-dk]%64), where “%” denotes the modulo operator and dk is the cyclic delay of transmitter k in 20 MHz samples. This expression assumes a 20 MHz sampling rate, such that there are 64 samples in a 3.2 microsecond interval. An alternative method of generating the cyclic shift is to apply a phase ramp rotation to all subcarrier values of L(k) prior to calculating the IFFT, such as that shown by the example of Equation 6.
l k ⁡ ( i ) = ∑ k = 0 63 ⁢ L ⁡ ( k ) ⁢ exp ⁡ ( - j ⁢ 2 ⁢ π ⁢ ⁢ k ⁢ ⁢ d k 64 ) ⁢ exp ⁡ ( j ⁢ 2 ⁢ π ⁢ ⁢ ik 64 ) ( Equ . ⁢ 6 )
Referring to FIG. 9B, preambles 910 1 is transmitted from the first antenna, preamble 910 2 is transmitted from the second antenna, and preamble 910 3 is transmitted from the third antenna of a communication system having three transmit antennas. The short sequence of preamble 910 2 have a cyclic shift of 200 as with respect to the short sequence of preamble 910 1. The ELT sequence of preamble 910 2 has a cyclic shift of 1050 ns with respect to the ELT sequence of preamble 910 1. Similarly, the Signal field of preamble 910 2 has a cyclic shift of 1050 ns with respect to the Signal field of preamble 910 1. The short sequence of preamble 910 3 have a cyclic shift of 400 ns with respect to the short sequence of preamble 910 1. The ELT sequence of preamble 910 3 have a cyclic shift of 2100 ns with respect to the ELT sequence of preamble 910 1. Similarly, the Signal field of preamble 910 3 has a cyclic shift of 2100 ns with respect to the Signal field of preamble 910 1. Other cyclic shifts per preamble part may be used.
The short-training sequence in each of the above preambles may or may not be the same as the legacy short training sequence defined by the 802.11a standard. Similarly, the ELT sequence may be the same as the legacy long training sequence or any one of the ELT sequences described. As describe above, the time span of the ELT sequence is divided by the number of transmit antennas from which cyclic shifts are derived. For example, with respect to the IEEE 802.11a preamble, the time span of the long training sequence, excluding the guard interval, is 3.2 μs. In the following, it is assumed that the Ns spatial streams are directly mapped onto the Nl transmit antennas, i.e., Ns=Nl, although it is understood that the present invention may be readily applied to more general space-time-frequency mappings where the Ns spatial streams are not directly mapped to the Nl transmit antennas. Furthermore, it is assumed that the cyclic shift on the first transmit antenna is 0, however, values other than 0 are also possible.
As is shown above, when there are two transmit antennas, i.e., N1=2, the cyclic shift on the second transmit antenna may be 3.2/2=1.6 μs. When there are three transmit antenna, Nt=3, the cyclic shift on the second and third transmit antennas two may be, respectively, 1.05 μs and 2.1 μs. For Nt=4, the cyclic shift on the second, third, and fourth transmit antennas may be respectively, 3.2/4=0.8 μs, 2*3.2/4=1.6 μs, and 3*3.2/4=2.4 μs, as shown in FIG. 9C.
The long-training sequence per transmit antenna may be the same as that of the IEEE 802.11a standard (FIG. 1), including two consecutive long training symbols. The corresponding cyclic shift associated with each transmit antenna and which is appended with a cyclic extension of 1.6 μs, forms the cyclically-shifted ELT symbols for that transmit antenna.
The odd training symbols of preamble 960 1 are formed by multiplying the tones of the long training symbols by the pattern {0, 1, 0, 1, 0, 1, 0 . . . 1}, assuming the tone indices are 0, 1, 2, . . . , Nc−1, where 0 is assumed to be the DC subcarrier and Nc equals the number of subcarriers. The modified even training symbols and signal field of preamble part 960 2 are formed by multiplying the even tones of the corresponding long training symbols and signals fields by the pattern {1, −1, 1, −1, 1, −1 . . . }, i.e., multiplying the original unmodified tones with the pattern {1, 0, −1, 0, 1, 0, −1, 0 . . . }. The tones in preamble parts 960 1 and 960 2 are orthogonal. Furthermore the pattern {1, −1, 1, −1, 1, −1 . . . } which is used to generate the modified even tones enables the transmitter to detect that the transmitted preamble, shown in FIG. 11, is not a legacy preamble.
In accordance with some embodiments of the present invention, a mixed-mode preamble includes legacy as well as modified preambles. FIG. 13 shows an exemplary mixed-mode preamble 1000 configured for transmission from a system having two-transmit antennas, in accordance with one embodiment of the present invention. Exemplary mixed mode preamble 1000 includes legacy 802.11a/g preamble portion 1050, that may be modified to indicate that an extended training part is appended. e.g., by setting the reserved bit of the legacy signal field, as well as a modified preamble portion 1060, as described above. Mixed mode preamble 1000 includes preamble 1000 1 that is transmitted from the first antenna and preamble 1000 2 that is transmitted from the second antenna. Short training sequence 1005 1, guard interval 1010 1, long training sequence 1015 1, and signal field 102 1 in combination form a legacy 802.11a/g preamble portion of preamble 1000 1 that is transmitted from the first transmit antenna. Guard interval 1025 1. ELT sequence 1030 1, and Signal field 1035 1 form the modified (extended) preamble portion of 1000 1. Similarly, short training sequence 1005 2, guard interval 1010 2, long training sequence 1015 2, and signal field 1020 2 in combination form a legacy 802.11a/g preamble portion of preamble 1000 2 that is transmitted from the first transmit antenna. Guard interval 1025 2, ELT sequence 1030 2, and Signal field 1035 2 form the extended preamble portion of preamble 1000 2 that is transmitted from the second antenna.
The extended preamble portions of preamble 1000 2 namely those identified by reference numerals 1020 1, 1025 1, 1030 1, 1035 1 of the first transmit antenna as well as 1020 2, 1025 2, 1030 2, 1035 2 of the second transmit antenna provide efficient training symbols for many systems, such MIMO OFDM systems. Therefore, when legacy devices as well as extended devices, like MIMO OFDM devices, are also part of the network, both the legacy as well as the extended devices are able to receive and process the preambles.
FIG. 15A (also shown in FIG. 2 as the sequence L2 except that the DC tone in sequence L2 is disposed at the beginning of the sequence) shows the 64 tones of an ELT sequence 1200 adapted for a 20 MHz channel, in accordance with one embodiment of the present invention. Accordingly, energy is transmitted on every single tone except the DC tone. ELT sequence 1200 includes the tones disposed in the 802.11a long-training sequence, shown in FIG. 15B. ELT sequence 1200 thus carries, next to the 802.11a subcarrier information, on subcarrier indices 27, . . . , 31 the values −1, −1, −1, 1, and on subcarrier indices −32, . . . , −27 the values −1, −1, 1, 1, 1, 1. The various tones of ELT sequence 1200 are selected such that the peak-to-average power of the ELT sequence 1200 is only a few tenths of a dB higher than the peak-to-average power of the 802.11a long training sequence.
FIG. 16A (also shown in FIG. 2 as the sequence L4 except that the DC tone in sequence L4 is disposed at the beginning of the sequence) shows the 128 tones of an ELT sequence 1300 adapted for a 40 MHz channel, in accordance with one embodiment of the present invention. Accordingly, energy is transmitted on every single tone except the DC tone. ELT sequence 1400 includes the tones disposed in the 802.11a long-training sequence, shown in FIG. 16B. ELT sequence 1300 carries, next to the two copies of the 802.11a on subcarrier indices −64, . . . , −59 the values −1, −1, 1, 1, 1, 1, on subcarrier index −32 the value −1, on subcarrier indices −5, . . . , −1 the values −1, −1, −1, 1, −1, on subcarrier indices 1, . . . , 5, values −1, 1, 1, 1, 1, on subcarrier index 32 the value −1, and on subcarrer indices 58, . . . , 63 the values −1, −1, −1, 1, −1.
At the receiver side, the channel estimates for each transmitter signal can be estimated by a process such as that shown in FIG. 19. As shown there, the process begins with receiving, signals and sampling for the long training sequence (step S1). Then, a 64-point FFT (or a 128-point FFT for 40 MHz modes, etc.) of the received long training sequence samples is done (step S2), as is done for conventional 802.11a preamble reception. Next, each subcarrier is multiplied by known pilot values (step S3), and an IFFT of the result is taken to get a 64-point, or 128-point, etc. impulse response estimate (step S4).
3) Signal field: The reserved bit of the Signal field can be used to signal the use of MIMO. It is also possible to extend the Signal field by transmitting an extra symbol. An example of this is shown in Boer. There is a reserved bit in the Signal field that is always zero for 802.11a devices but could be set to 1 to signal MEMO packets. It is also possible to send an extra signal field symbol after the normal 802.11a symbol to signal MIMO rates.
transmitting at least first and second preambles configured for transmission from first and second transmit antennas of a wireless communication system, wherein the first preamble comprises:
a long training sequence field defined by the odd tones of a legacy long training sequence field;
a guard interval field generated from time-domain representation of the odd tones of the long training sequence; and
a signal field defined by the odd tones of a legacy signal field; and
wherein the second preamble comprises:
a short training sequence field cyclically shifted with respect to the short training field of the first preamble;
a long training sequence field defined by the even tones of the legacy long training sequence field;
a guard interval field generated from time-domain representation of the long training sequence of the second preamble; and
a signal field defined by the even tones of the legacy signal field.
2. The method of claim 1, wherein the legacy long training sequence field corresponds to a Wi-Fi preamble long training sequence field, and wherein the legacy signal field corresponds to a Wi-Fi preamble signal field.
3. The method of claim 1, wherein the odd tones of a given sequence are generated by multiplying the given sequence by a pattern of alternating 0 and 1 values, and wherein the even tones of a given sequence are generated by multiplying the given sequence by a pattern of alternating 0 and 1 values where every other 1 value has an inverted sign.
4. A method for transmitting a training sequence, the method comprising:
transmitting first, second, third, and fourth preambles configured for transmission from first, second, third and fourth transmit antennas of a wireless communication system, wherein the first preamble comprises:
a first long training sequence field defined by the odd tones of a legacy long training sequence field;
a second long training sequence defined by the odd tones of the legacy long training sequence field;
first and second guard interval fields generated from time-domain representation of the odd tones of the first or second long training sequence field; and
a signal field defined by the odd tones of a legacy signal field;
a short training sequence field having a cyclic shift with respect to the short training sequence field of the first preamble;
a first long training sequence field defined by the even tones of the legacy long training sequence field;
a second long training sequence defined by the even tones of the legacy long training sequence field;
first and second guard interval fields generated from time-domain representation of the first or second long training sequence of the second preamble; and
a signal field defined by the even tones of the legacy signal field;
wherein the third preamble comprises:
a short training sequence field having a cyclic shift with respect to the short training sequence field of the second preamble;
a first long training sequence field defined by the odd tones of the legacy long training sequence and having a cyclic shift with respect to the first long training sequence of the second preamble;
a second long training sequence defined by the odd tones of the legacy long training sequence and having a cyclic shift with respect to the second long training sequence of the second preamble; wherein the second long training sequence field of the third preamble has inverted sign with respect to the second long training sequence field of the first preamble;
first and second guard interval fields defined respectively by cyclic extensions of the first and second long training sequences of the third preamble; and
a signal field generated from time-domain representation of the odd tones of the first or second long training sequences of the third preamble and having a cyclic shift with respect to the signal field of the second preamble; and
wherein the fourth preamble comprises:
a first long training sequence field defined by the even tones of the legacy long training sequence field and having a cyclic shift with respect to the first long training sequence field of the third preamble;
a second long training sequence defined by the even tones of the legacy long training sequence field and having a cyclic shift with respect to the second long training sequence field of the third preamble, wherein the second long training sequence field of the fourth preamble has inverted sign with respect to the second long training sequence field of the first preamble;
first and second guard interval fields defined by a legacy guard interval field; and
a signal field generated from time-domain representation of the tones of the first or second long training sequences of the fourth preamble and having a cyclic shift with respect to the signal field of the third preamble.
5. The method of claim 4, wherein the legacy long training sequence field corresponds to a Wi-Fi preamble long training sequence field, wherein the legacy signal field corresponds to a Wi-Fi preamble signal field, and wherein the legacy guard interval field corresponds to a Wi-Fi preamble guard interval field.
6. The method of claim 4, wherein the odd tones of a given sequence are generated by multiplying the given sequence by a pattern of alternating 0 and 1 values, and wherein the even tones of a given sequence are generated by multiplying the given sequence by a pattern of alternating 0 and 1 values where every other 1 value has an inverted sign.
7. A method for transmitting a training sequence, the method comprising:
transmitting at least first and second preambles configured for transmission from at least first and second transmit antennas of a wireless communication system,
wherein each of the first and second preambles comprise a first part and a second part,
wherein the first part of each of the first and second preambles comprises a legacy preamble, and
wherein the second part of the first preamble comprises a long training sequence distinct from legacy long training sequence;
wherein the first part of the second preamble has a cyclic shift with respect to the first part of the first preamble;
wherein the second part of the second preamble comprises a long training sequence distinct from the legacy long training sequence; and
wherein the long training sequence of the second preamble has a cyclic shift with respect to the long training sequence of the first preamble.
8. The method of claim 7 wherein the second part of each of the first and second preambles comprises a signal field distinct from a legacy signal field, and
wherein the signal field of the second part of the second preamble has a cyclic shift with respect to the signal field of the second part of the first preamble.
9. The method of claim 7 wherein each of the long training sequence of the second part of each of the first and second preambles has a second plurality of tones of which only the DC tone has a zero value.
10. The method of claim 7, wherein the legacy preamble corresponds to a Wi-Fi preamble, and wherein the legacy long training sequence field corresponds to a Wi-Fi preamble long training sequence field.
11. A method for transmitting a training sequence, the method comprising:
wherein each of the first and second preambles comprises a first part and a second part,
wherein the first part of each of the first and second preambles comprises a legacy preamble,
wherein the second part of the first preamble comprises a long training sequence having a plurality of tones defined by the odd tones of a legacy long training sequence, and
wherein the second part of the second preamble comprises a long training sequence defined by the even tones of the legacy long training sequence.
12. The method of claim 11, wherein the legacy preamble corresponds to a Wi-Fi preamble, and wherein the legacy long training sequence field corresponds to a Wi-Fi preamble long training sequence field.
13. The method of claim 11, wherein the odd tones of a given sequence are generated by multiplying the given sequence by a pattern of alternating 0 and 1 values, and wherein the even tones of a given sequence are generated by multiplying the given sequence by a pattern of alternating 0 and 1 values where every other 1 value has an inverted sign.
14. A method for transmitting a training sequence, the method comprising:
wherein the first part of the second preamble has a cyclic shift with respect to the first part of the first preamble,
wherein the second part of the first preamble comprises a signal field having a plurality of tones defined by the odd tones of a legacy signal field, and
wherein the second part of the second preamble comprises a signal field having a plurality of tones defined by the even tones of the legacy signal field.
15. The method of claim 14, wherein the legacy preamble corresponds to a Wi-Fi preamble, and wherein the legacy signal field corresponds to a Wi-Fi preamble signal field.
16. The method of claim 14, wherein the odd tones of a given sequence are generated by multiplying the given sequence by a pattern of alternating 0 and 1 values, and wherein the even tones of a given sequence are generated by multiplying the given sequence by a pattern of alternating 0 and 1 values where every other 1 value has an inverted sign.
a processor operative to generate a training sequence comprising at least first and second preambles configured for transmission from first and second transmit antennas of a wireless communication system, wherein the first preamble comprises:
a guard interval field generated from time-domain representation of the odd tones of the legacy long training sequence; and
a short training sequence field being cyclically shifted with respect to the short training field of the first preamble;
a processor operative to generate a training sequence comprising first, second, third, and fourth preambles configured for transmission from first, second, third and fourth transmit antennas of a wireless communication system, wherein the first preamble comprises:
a processor operative to generate a training sequence comprising at least first and second preambles configured for transmission from at least first and second transmit antennas of a wireless communication system,
wherein the second part of the first preamble comprises a long training sequence distinct from a legacy long training sequence;
20. The apparatus of claim 19 wherein the second part of each of the first and second preambles comprises a signal field distinct from a legacy signal field, and
21. The apparatus of claim 19 wherein each of the long training sequence of the second part of each of the first and second preambles has a second plurality of tones of which only the DC tone has a zero value.
means for generating a training sequence comprising at least first and second preambles configured for transmission from first and second transmit antennas of a wireless communication system, wherein the first preamble comprises:
means for generating a training sequence comprising first, second, third, and fourth preambles configured for transmission from first, second, third and fourth transmit antennas of a wireless communication system, wherein the first preamble comprises:
means for generating a training sequence comprising at least first and second preambles configured for transmission from at least first and second transmit antennas of a wireless communication system,
27. The wireless communications device of claim 26 wherein the second part of each of the first and second preambles comprises a signal field distinct from a legacy signal field, and
28. The wireless communications device of claim 26 wherein each of the long training sequence of the second part of each of the first and second preambles has a second plurality of tones of which only the DC tone has a zero value.
29. A wireless communications device comprising:
31. A computer program product residing on a processor-readable medium and comprising processor-readable instructions configured to cause a processor to:
transmit at least first and second preambles configured for transmission from first and second transmit antennas of a wireless communication system, wherein the first preamble comprises:
32. A computer program product residing on a processor-readable medium and comprising processor-readable instructions configured to cause a processor to:
transmit first, second, third, and fourth preambles configured for transmission from first, second, third and fourth transmit antennas of a wireless communication system, wherein the first preamble comprises:
33. A computer program product residing on a processor-readable medium and comprising processor-readable instructions configured to cause a processor to:
transmit at least first and second preambles configured for transmission from at least first and second transmit antennas of a wireless communication system,
34. The computer program product of claim 33 wherein the second part of each of the first and second preambles comprises a signal field distinct from a legacy signal field, and
35. The computer program product of claim 33 wherein each of the long training sequence of the second part of each of the first and second preambles has a second plurality of tones of which only the DC tone has a zero value.
36. A computer program product residing on a processor-readable medium and comprising processor-readable instructions configured to cause a processor to:
37. A computer program product residing on a processor-readable medium and comprising processor-readable instructions configured to cause a processor to:
US12/552,705 2003-04-10 2009-09-02 Modified preamble structure for IEEE 802.11A extensions to allow for coexistence and interoperability between 802.11A devices and higher data rate, MIMO or otherwise extended devices Active 2025-04-07 US8743837B2 (en)
US11/140,349 Continuation US7599332B2 (en) 2003-04-10 2005-05-27 Modified preamble structure for IEEE 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, MIMO or otherwise extended devices
US20100061402A1 US20100061402A1 (en) 2010-03-11
US8743837B2 true US8743837B2 (en) 2014-06-03
ID=41811422
US12/552,705 Active 2025-04-07 US8743837B2 (en) 2003-04-10 2009-09-02 Modified preamble structure for IEEE 802.11A extensions to allow for coexistence and interoperability between 802.11A devices and higher data rate, MIMO or otherwise extended devices
US (1) US8743837B2 (en)
JPH11177544A (en) 1997-12-09 1999-07-02 Nec Corp Reception synchronization circuit, receiver using it and digital communication system
US20020118771A1 (en) 2000-11-29 2002-08-29 Peter Larsson Methods and arrangements in a telecommunications system
JP2003503889A (en) 1999-06-28 2003-01-28 サムスン エレクトロニクス カンパニー リミテッド Forward power control apparatus and method in a mobile communication system of the discontinuous transmission mode
US20040198265A1 (en) 2002-12-31 2004-10-07 Wallace Bradley A. Method and apparatus for signal decoding in a diversity reception system with maximum ratio combining
US8218427B2 (en) * 2003-12-27 2012-07-10 Electronics And Telecommunications Research Institute Preamble configuring method in the wireless LAN system, and a method for a frame synchronization
US675322A (en) * 1900-09-20 1901-05-28 James W Byers Cleaner for incandescent gas-burners.
2009-09-02 US US12/552,705 patent/US8743837B2/en active Active
Boer, Jan et al.: "Backwards compatability: How to make a MIMO-OFDM system backwards compatible and coexistence with 11a/g at the link level", 2003, IEEE 802.11-03/714r0, slides 1-26.
Chinese Office Action mailed Feb. 28, 2011 for Chinese application No. 200580049854.8, 26 pages.
European OA dated Aug. 19, 2008 for EP Application Serial No. 05 729 464.7-2415,17pages.
IEEE STD 802.11a-1999, Supplement to IEEE Standard for Information technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements-Part 11: Wireless LAN Medium Access Control (MAC).
IEEE STD 802.11a-1999, Supplement to IEEE Standard for Information technology—Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements—Part 11: Wireless LAN Medium Access Control (MAC).
International Preliminary Report on Patentability-PCT/US05/018566-The International Bureau of WIPO, Geneva, Switzerland-Nov. 29, 2006.
International Preliminary Report on Patentability—PCT/US05/018566—The International Bureau of WIPO, Geneva, Switzerland—Nov. 29, 2006.
International Search Report−PCT/US05/018566—International Search Authority, US—Apr. 12, 2006.
International Search Report-PCT/US05/018566-International Search Authority, US-Apr. 12, 2006.
James Gardner et at., Non-Final Office Action, U.S. Appl. No. 10/820,440, US-Nov. 28, 2008.
Office Action for Japanese Patent Application Serial No. 2008-502955 dated Mar. 8, 2011, 2 pages.
Office Action in U.S. Appl. No. 11/139,925 dated Apr. 1, 2008. 22 pages.
Office Action in U.S. Appl. No. 11/139,925 dated Sep. 3, 2008, 28 pages.
Syed Aon Mujtaba, Agere Systems, et al., "TGn Sync Compelte Proposal", Jan. 18, 2005, pp. 24-42, IEEE 802.11-04/888r8.
Written Opinion-PCT/US05/018566-International Search Authority, US-Apr. 12, 2006.
Written Opinion—PCT/US05/018566—International Search Authority, US—Apr. 12, 2006.
US20100061402A1 (en) 2010-03-11
JP5410527B2 (en) 2014-02-05 Preamble extension for communication
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:VAN ZELST, ALBERT;JONES, VINCENT K.;VAN NEE, D. J. RICHARD;SIGNING DATES FROM 20050802 TO 20050816;REEL/FRAME:023184/0432