Data unit format for multi-user data in long-range wireless local area networks (WLANs)

Patent metadata

Field	Value
Publication number	US-8942320-B2
Application number	US-201213663106-A
Country	US
Kind code	B2
Filing date	Oct 29, 2012
Priority date	Oct 27, 2011
Publication date	Jan 27, 2015
Grant date	Jan 27, 2015

Abstract

A method includes receiving a data unit that includes a signal (SIG) field and a data field. The SIG field provides information for interpreting the data field. The method also includes detecting a first symbol constellation rotation of at least a first orthogonal frequency division multiplexing (OFDM) symbol in the SIG field of the data unit, determining, based at least in part on the detected first symbol constellation rotation, a number of information bits per OFDM symbol in the SIG field of the data unit, processing the SIG field of the data unit according to the determined number of information bits per OFDM symbol in the SIG field, and processing the data field of the data unit according to the information for interpreting the data field as provided in the SIG field of the data unit.

First claim

What is claimed is:

1. A method comprising:
receiving a data unit that includes a signal (SIG) field and a data field, wherein the SIG field provides information for interpreting the data field;
detecting a first symbol constellation rotation of at least a first orthogonal frequency division multiplexing (OFDM) symbol in the SIG field of the data unit;
determining, based at least in part on the detected first symbol constellation rotation, a number of information bits per OFDM symbol in the SIG field of the data unit;
processing the SIG field of the data unit according to the determined number of information bits per OFDM symbol in the SIG field; and
processing the data field of the data unit according to the information for interpreting the data field as provided in the SIG field of the data unit.

2. A method according to claim 1 , wherein:
determining a number of information bits per OFDM symbol in the SIG field includes determining one or more of (i) a modulation type of the SIG field, (ii) a coding rate of the SIG field, and (iii) a number of bit repetitions of the SIG field; and
processing the SIG field of the data unit according to the determined number of information bits per OFDM symbol in the SIG field includes processing the SIG field of the data unit according to the determined one or more of (i) the modulation type, (ii) the coding rate, and (iii) the number of bit repetitions.

3. A method according to claim 2 , wherein detecting a first symbol constellation rotation includes detecting whether at least the first OFDM symbol in the SIG field of the data unit is binary phase shift key (BPSK) modulated or quaternary BPSK (QBPSK) modulated.

4. A method according to claim 3 , wherein:
determining one or more of (i) a modulation type of the SIG field, (ii) a coding rate of the SIG field, and (iii) a number of bit repetitions of the SIG field includes determining whether the SIG field includes a first number of bit repetitions or a second number of bit repetitions; and
processing the SIG field of the data unit according to the determined number of information bits per OFDM symbol in the SIG field includes decoding the SIG field according to the determined number of bit repetitions.

5. A method according to claim 1 , the method further comprising determining, based at least in part on (i) the detected first symbol constellation rotation or (ii) a second symbol constellation rotation of at least a second OFDM symbol within the SIG field of the data unit, whether at least a portion of a preamble of the data unit is arranged according to a shorter format or a longer format.

6. A method according to claim 5 , wherein determining whether at least a portion of a preamble of the data unit is arranged according to a shorter format or a longer format includes determining whether a portion of the preamble after the SIG field is arranged according to a single-user format or a multi-user format.

7. An apparatus comprising:
a network interface configured to
receive a data unit that includes a signal (SIG) field and a data field, wherein the SIG field provides information for interpreting the data field,
detect a first symbol constellation rotation of at least a first orthogonal frequency division multiplexing (OFDM) symbol in the SIG field of the data unit,
determine, based on the detected first symbol constellation rotation, a number of information bits per OFDM symbol in the SIG field of the data unit,
process the SIG field of the data unit according to the determined number of information bits per OFDM symbol in the SIG field, and
process the data field of the data unit according to the information for interpreting the data field as provided in the SIG field of the data unit.

8. An apparatus according to claim 7 , wherein the network interface is configured to:
determine the number of information bits per OFDM symbol in the SIG field at least in part by determining one or more of (i) a modulation type of the SIG field, (ii) a coding rate of the SIG field, and (iii) a number of bit repetitions of the SIG field; and
process the SIG field of the data unit according to the determined number of information bits per OFDM symbol in the SIG field at least in part by processing the SIG field of the data unit according to the determined one or more of (i) the modulation type, (ii) the coding rate, and (iii) the number of bit repetitions.

9. An apparatus according to claim 8 , wherein the network interface is configured to detect the first symbol constellation rotation at least in part by detecting whether at least the first OFDM symbol in the SIG field of the data unit is binary phase shift key (BPSK) modulated or quaternary BPSK (QBPSK) modulated.

10. An apparatus according to claim 9 , wherein the network interface is configured to:
determine one or more of (i) the modulation type of the SIG field, (ii) the coding rate of the SIG field, and (iii) the number of bit repetitions of the SIG field at least in part by determining whether the SIG field includes a first number of bit repetitions or a second number of bit repetitions; and
process the SIG field of the data unit according to the determined number of information bits per OFDM symbol in the SIG field at least in part by decoding the SIG field according to the determined number of bit repetitions.

11. An apparatus according to claim 7 , wherein the network interface is further configured to determine, based at least in part on (i) the detected first symbol constellation rotation or (ii) a second symbol constellation rotation of at least a second OFDM symbol within the SIG field of the data unit, whether at least a portion of a preamble of the data unit is arranged according to a shorter format or a longer format.

12. An apparatus according to claim 11 , wherein the network interface is configured to determine whether at least the portion of the preamble of the data unit is arranged according to the shorter format or the longer format at least in part by determining whether a portion of the preamble after the SIG field is arranged according to a single-user format or a multi-user format.

13. A method comprising:
determining a first number of information bits per orthogonal frequency division multiplexing (OFDM) symbol to be used in generating a data field of a data unit;
determining, based on the first number of information bits per OFDM symbol, a second number of information bits per OFDM symbol to be used in generating a signal (SIG) field of the data unit;
determining, based on the second number of information bits per OFDM symbol, a first symbol constellation rotation;
generating the SIG field of the data unit according to the second number of information bits per symbol, wherein
the SIG field provides a receiver with information for interpreting the data field, and
generating the SIG field of the data unit includes generating at least a first OFDM symbol according to the first symbol constellation rotation; and
generating the data field of the data unit according to the first number of information bits per OFDM symbol.

14. A method according to claim 13 , wherein determining a first number of information bits per OFDM symbol to be used in generating the data field includes determining the first number of information bits per OFDM symbol based on channel state information.

15. A method according to claim 13 , wherein determining a second number of information bits per OFDM symbol to be used in generating the SIG field includes setting the second number of information bits per OFDM symbol equal to the first number of information bits per OFDM symbol

Assignees

• Marvell World Trade Ltd

Inventors

• Zhang Hongyuan
• Banerjea Raja

Classifications

• H04L1/0009

  by adapting the channel coding (H04L1/1812 takes precedence) · CPC title

• H04W84/12

  WLAN [Wireless Local Area Networks] · CPC title

• H04L1/0003

  by switching between different modulation schemes · CPC title

• H04L1/08

  by repeating transmission, e.g. Verdan system {(H04L1/1858 and H04L1/189 take precedence)} · CPC title

• H04L27/2666 Primary

  Acquisition of further OFDM parameters, e.g. bandwidth, subcarrier spacing, or guard interval length · CPC title