Preamble with modified signal field (SIG) for use in wireless communications

• US 9,197,473 B2
• Filed: 06/06/2014
• Issued: 11/24/2015
• Est. Priority Date: 06/06/2013
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Porat, Ron, Jindal, Nihar
• Primary Examiner(s): Corrielus, Jean B
• Application Number:
  US14/297,739
• Publication Number:
  US 20140362935A1
• Time in Patent Office: 536 Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0004 applied to control information
• CPC Class Codes: H04L 1/0005 applied to payload information
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/26132 using repetition
• CPC Class Codes: H04L 27/2634 Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/003 Arrangements for allocating sub-channels of the transmission path
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers

Abstract

A wireless communication device (‘device’) is configured to generate an OFDM/A packet that includes at least one OFDM/A symbol that includes at least one SIG having SIG information modulated on only even (or odd) sub-carriers and does not include any information modulated on odd (or even) sub-carriers of a set of OFDM/A sub-carriers. The set of OFDM/A sub-carriers may be all or less than all of available sub-carriers. The device may generate the packet to include a preamble and a payload such that the payload, which may be composed of at least one additional OFDM/A symbol, includes data modulated on some or all of the sub-carriers of the set of OFDM/A sub-carriers. The device can modulate and transmit SIG information and data differently within the preamble and the payload (e.g., with higher ordered modulation or MCS for the data and less power per sub-carrier than for the preamble).

Claims

1. A wireless communication device comprising:

a communication interface; and

a processor, at least one of the processor or the communication interface configured to;

generate a preamble for an orthogonal frequency division multiplexing (OFDM) packet that includes the preamble and a payload, wherein the payload includes data modulated on all sub-carriers of a set of OFDM sub-carriers, and that includes at least one OFDM symbol that includes at least one signal field (SIG) having SIG information modulated on only even sub-carriers of the set of OFDM sub-carriers, wherein odd sub-carriers of the set of OFDM sub-carriers are devoid of any information modulated thereon; and

transmit the OFDM packet to another wireless communication device using a first transmission power for each of the even sub-carriers of the set of OFDM sub-carriers that includes the SIG information modulated in the preamble that is approximately double a second transmission power for each of the sub-carriers that includes the data modulated in the payload.

2. The wireless communication device of claim 1 further comprising:

a laptop computer, a tablet, a personal digital assistant, a personal computer, or a cellular telephone.

3. The wireless communication device of claim 1, wherein the at least one of the processor or the communication interface is further configured to:

generate the OFDM packet that includes the preamble and the payload, wherein the payload includes the data modulated on the all sub-carriers of the set of OFDM sub-carriers using first modulation coding set (MCS) that is a higher ordered MCS and includes a higher number of constellation points relative to second MCS used for the SIG information modulated on only the even sub-carriers of the set of OFDM sub-carriers.

4. The wireless communication device of claim 1, wherein the at least one of the processor or the communication interface is further configured to:

generate the preamble for the OFDM packet that includes another OFDM symbol that includes another SIG having other SIG information corresponding to a first IEEE 802.11 communication standard that is modulated on the all sub-carriers of the set of OFDM sub-carriers, wherein the other SIG is followed by the at least one signal field (SIG) includes first, second, and third SIGs having first, second, and third SIG information corresponding to a second IEEE 802.11 communication standard, wherein the first IEEE 802.11 communication standard is legacy relative to the second IEEE 802.11 communication standard, wherein the first SIG includes first OFDM symbol having first SIG information modulated on only the even sub-carriers of the set of OFDM sub-carriers and is devoid of any information modulated on the odd sub-carriers of the set of OFDM sub-carriers, the second SIG includes second OFDM symbol having second SIG information modulated on only the even sub-carriers of the set of OFDM sub-carriers and is devoid of any information modulated on the odd sub-carriers of the set of OFDM sub-carriers, and the third SIG includes third at least one OFDM symbol having third SIG information, and wherein length of the third SIG and number of OFDM symbols within the third at least one OFDM symbol is indicated by at least one of the first SIG or the second SIG.

5. The wireless communication device of claim 1, wherein the at least one of the processor or the communication interface is further configured to:

generate the preamble for the OFDM packet that includes another OFDM symbol that include another SIG having other SIG information corresponding to a first IEEE 802.11 communication standard that is modulated on the all sub-carriers of the set of OFDM sub-carriers, wherein the other SIG is followed by the at least one signal field (SIG) includes first, second, and third SIGs having first, second, and third SIG information corresponding to a second IEEE 802.11 communication standard, wherein the first IEEE 802.11 communication standard is legacy relative to the second IEEE 802.11 communication standard, wherein the first SIG includes first OFDM symbol having first SIG information modulated on only the even sub-carriers of the set of OFDM sub-carriers and is devoid of any information modulated on the odd sub-carriers of the set of OFDM sub-carriers, the second SIG includes second OFDM symbol having second SIG information modulated on only the even sub-carriers of the set of OFDM sub-carriers and is devoid of any information modulated on the odd sub-carriers of the set of OFDM sub-carriers, and the third SIG includes third two or more OFDM symbols having third SIG information, and wherein length of the third SIG and number of OFDM symbols within the third two or more OFDM symbols is indicated by 90 degree phase rotation of a last of the third two or more OFDM symbols relative to other OFDM symbols of the third two or more OFDM symbols.

6. The wireless communication device of claim 1, wherein the at least one of the processor or the communication interface is further configured to:

generate the preamble for the OFDM packet that includes two other SIGs that include a first SIG having other SIG information corresponding to a first IEEE 802.11 communication standard and a second SIG having cyclically shifted copy of the other SIG information corresponding to the first IEEE 802.11 communication standard, wherein the two other SIGs are followed by the at least one SIG having the SIG information, wherein the SIG information corresponds to a second IEEE 802.11 communication standard, wherein the first IEEE 802.11 communication standard is legacy relative to the second IEEE 802.11 communication standard.

7. The wireless communication device of claim 1 further comprising:

an access point (AP), wherein the another wireless communication device is a wireless station (STA).

8. The wireless communication device of claim 1 further comprising:

a wireless station (STA), wherein the another wireless communication device is an access point (AP) or another STA.

9. A wireless communication device comprising:

a communication interface; and

a processor, at least one of the processor or the communication interface configured to;

receive, from another wireless communication device, an orthogonal frequency division multiplexing (OFDM) packet that includes at least one OFDM symbol;

process a preamble of the OFDM packet within the at least one OFDM symbol to determine on which sub-carriers of a set of OFDM sub-carriers signal field (SIG) information is modulated;

classify, when SIG information is modulated on only even sub-carriers of the set of OFDM sub-carriers and when odd sub-carriers of the set of OFDM sub-carriers are devoid of any information modulated thereon, the OFDM packet as first IEEE 802.11 communication standard based packet and process the OFDM packet based on the first IEEE 802.11 communication standard; and

classify, when SIG information is modulated on all sub-carriers of the set of OFDM sub-carriers, the OFDM packet as second IEEE 802.11 communication standard based packet and process the OFDM packet based on the second IEEE 802.11 communication standard.

10. The wireless communication device of claim 9, wherein the at least one of the processor or the communication interface is further configured to:

process the preamble of the OFDM packet to determine a last OFDM symbol of a plurality of OFDM symbols that includes the SIG information based on information included within at least one other OFDM of the plurality of OFDM symbols that precedes the last OFDM symbol.

11. The wireless communication device of claim 9, wherein the at least one of the processor or the communication interface is further configured to:

process the preamble of the OFDM packet to determine a last OFDM symbol of a plurality of OFDM symbols that includes the SIG information based on a 90 degree phase rotation of last OFDM symbols relative to other OFDM symbols of the plurality of OFDM symbols that precedes the last OFDM symbol.

12. The wireless communication device of claim 9, wherein the at least one of the processor or the communication interface is further configured to:

process the OFDM packet, when the OFDM packet is classified as the first IEEE 802.11 communication standard based packet, by demodulating SIG information from only the even sub-carriers of the set of OFDM sub-carriers within the at least one OFDM symbol of the preamble of the OFDM packet and by demodulating data from the all sub-carriers of the set of OFDM sub-carriers within other at least one OFDM symbol of a payload of the OFDM packet.

13. The wireless communication device of claim 9 further comprising:

a wireless station (STA), wherein the another wireless communication device is an access point (AP) or another STA.

14. A method for execution by a wireless communication device, the method comprising:

generating a preamble for an orthogonal frequency division multiplexing (OFDM) packet that includes the preamble and a payload that includes at least one OFDM symbol that includes at least one signal field (SIG) having SIG information modulated on only even sub-carriers of a set of OFDM sub-carriers, wherein odd sub-carriers of the set of OFDM sub-carriers are devoid of any information modulated thereon, wherein the payload includes data modulated on all sub-carriers of the set of OFDM sub-carriers using first modulation coding set (MCS) that is a higher ordered MCS and includes a higher number of constellation points relative to second MCS used for the SIG information modulated on only the even sub-carriers of the set of OFDM sub-carriers; and

transmitting, via a communication interface of the wireless communication, the OFDM packet to another wireless communication device.

15. The method of claim 14 further comprising:

transmitting, via the communication interface of the wireless communication, the OFDM packet to the another wireless communication device using a first transmission power for each of the even sub-carriers of the set of OFDM sub-carriers that includes the SIG information modulated in the preamble that is approximately double a second transmission power for each of the sub-carriers that includes the data modulated in the payload.

16. The method of claim 14, wherein the wireless communication device includes a laptop computer, a tablet, a personal digital assistant, a personal computer, or a cellular telephone.

17. The method of claim 14 further comprising:

generating the preamble for the OFDM packet that includes another OFDM symbol that include another SIG having other SIG information corresponding to a first IEEE 802.11 communication standard that is modulated on the all sub-carriers of the set of OFDM sub-carriers, wherein the other SIG is followed by the at least one signal field (SIG) includes first, second, and third SIGs having first, second, and third SIG information corresponding to a second IEEE 802.11 communication standard, wherein the first IEEE 802.11 communication standard is legacy relative to the second IEEE 802.11 communication standard, wherein the first SIG includes first OFDM symbol having first SIG information modulated on only the even sub-carriers of the set of OFDM sub-carriers and is devoid of any information modulated on the odd sub-carriers of the set of OFDM sub-carriers, the second SIG includes second OFDM symbol having second SIG information modulated on only the even sub-carriers of the set of OFDM sub-carriers and is devoid of any information modulated on the odd sub-carriers of the set of OFDM sub-carriers, and the third SIG includes third at least one OFDM symbol having third SIG information, and wherein length of the third SIG and number of OFDM symbols within the third at least one OFDM symbol is indicated by at least one of the first SIG or the second SIG.

18. The method of claim 14 further comprising:

generating the preamble for the OFDM packet that includes another OFDM symbol that include another SIG having other SIG information corresponding to a first IEEE 802.11 communication standard that is modulated on the all sub-carriers of the set of OFDM sub-carriers, wherein the other SIG is followed by the at least one signal field (SIG) includes first, second, and third SIGs having first, second, and third SIG information corresponding to a second IEEE 802.11 communication standard, wherein the first IEEE 802.11 communication standard is legacy relative to the second IEEE 802.11 communication standard, wherein the first SIG includes first OFDM symbol having first SIG information modulated on only the even sub-carriers of the set of OFDM sub-carriers and is devoid of any information modulated on the odd sub-carriers of the set of OFDM sub-carriers, the second SIG includes second OFDM symbol having second SIG information modulated on only the even sub-carriers of the set of OFDM sub-carriers and is devoid of any information modulated on the odd sub-carriers of the set of OFDM sub-carriers, and the third SIG includes third two or more OFDM symbols having third SIG information, and wherein length of the third SIG and number of OFDM symbols within the third two or more OFDM symbols is indicated by 90 degree phase rotation of a last of the third two or more OFDM symbols relative to other OFDM symbols of the third two or more OFDM symbols.

19. The method of claim 14 further comprising:

generating the preamble for the OFDM packet that includes two other SIGs that include a first SIG having other SIG information corresponding to a first IEEE 802.11 communication standard and a second SIG having cyclically shifted copy of the other SIG information corresponding to the first IEEE 802.11 communication standard, wherein the two other SIGs are followed by the at least one SIG having the SIG information, wherein the SIG information corresponds to a second IEEE 802.11 communication standard, wherein the first IEEE 802.11 communication standard is legacy relative to the second IEEE 802.11 communication standard.

20. The method of claim 14, wherein the wireless communication device is a wireless station (STA), wherein the another wireless communication device is an access point (AP) or another STA.