Physical layer frame format for WLAN
A first portion of a physical layer (PHY) preamble of a PHY data unit is generated for transmission via a communication channel that comprises a plurality of sub-channels. A first portion of the PHY preamble is generated to include a legacy portion and a plurality of first non-legacy signal fields spanning the respective sub-channels. A second portion of a PHY preamble that immediately follows the first portion of the PHY preamble of the PHY data unit is generated to include: a non-legacy short training field spanning all sub-channels in the plurality of sub-channels, a plurality of non-legacy long training fields immediately following the non-legacy short training field, each non-legacy training field spanning all sub-channels in the plurality of sub-channels, and a second non-legacy signal field immediately following the plurality of non-legacy long training fields, the second-legacy signal field spanning all sub-channels in the plurality of sub-channels.
1. A method for generating and transmitting a physical layer (PHY) data unit for transmission via a communication channel that comprises a plurality of sub-channels, the method comprising:
generating, at a communication device, a first portion of a PHY preamble of the PHY data unit, the first portion of the PHY preamble being generated to include:
a plurality of legacy short training fields (L-STFs) spanning respective sub-channels,
a plurality of legacy long training fields (L-LTFs) spanning the respective sub-channels,
a plurality of legacy signal fields (L-SIGs) spanning the respective sub-channels, and
a plurality of first non-legacy signal fields spanning the respective sub-channels;
generating, at the communication device, a second portion of a PHY preamble of the PHY data unit, the second portion of the PHY preamble immediately following the first portion of the PHY preamble and being generated to include:
a non-legacy short training field spanning all sub-channels in the plurality of sub-channels,
a plurality of non-legacy long training fields immediately following the non-legacy short training field, each non-legacy training field spanning all sub-channels in the plurality of sub-channels, and
a second non-legacy signal field immediately following the plurality of non-legacy long training fields, the second non-legacy signal field spanning all sub-channels in the plurality of sub-channels;
generating, at the communication device, a PHY payload of the PHY data unit that immediately follows the second non-legacy signal field; and
transmitting, by the communication device, the PHY data unit via the communication channel.
2. The method of claim 1 , wherein generating the first portion of the PHY preamble comprises generating two orthogonal frequency division multiplexing (OFDM) symbols that include the plurality of first non-legacy signal fields.
3. The method of claim 2 , wherein generating the two OFDM symbols comprises generating the two OFDM symbols so that each non-legacy field utilizes a respective 52 OFDM tones in the two OFDM symbols.
4. The method of claim 2 , wherein generating the second portion of the PHY preamble comprises generating a single OFDM symbol that includes the second non-legacy signal field.
5. The method of claim 4 , wherein:
generating the two OFDM symbols comprises generating the two OFDM symbols to each utilize a first quantity of OFDM tones; and
generating the single OFDM symbol comprises generating the single OFDM symbol to utilize a second quantity of OFDM tones different than the first quantity of OFDM tones.
6. The method of claim 1 , wherein generating the first portion of the PHY preamble comprises generating each first non-legacy signal field to include information that indicates whether the PHY data unit is a multi-user PHY data unit.
7. The method of claim 1 , wherein when the PHY data unit is a multi-user PHY data unit:
generating the second portion of the PHY preamble comprises generating the second non-legacy signal field to include respective PHY information specific for respective intended receivers; and
transmitting the PHY data unit comprises transmitting the second non-legacy signal field using space division multiple access (SDMA) so that the respective PHY information specific for respective intended receivers are transmitted via different respective spatial streams.
8. The method of claim 7 , wherein when the PHY data unit is a multi-user PHY data unit:
generating the second non-legacy signal field to include different respective information for respective receivers includes generating the second non-legacy signal field to include respective modulation and coding scheme (MCS) information indicating respective MCSs for respective PHY payloads intended for respective receivers.
9. The method of claim 7 , wherein generating the first portion of the PHY preamble comprises generating each of the first non-legacy signal fields to include common PHY information for all intended receivers.
10. The method of claim 9 , wherein generating the first portion of the PHY preamble comprises generating each of the first non-legacy signal fields to indicate a quantity of non-legacy long training fields in the second portion of the PHY preamble.
11. The method of claim 1 , wherein when the PHY data unit is a multi-user PHY data unit:
generating the first portion of the PHY preamble comprises generating each of the first non-legacy signal fields to include common PHY information for all intended receivers;
generating the second portion of the PHY preamble comprises generating the second non-legacy signal field to include respective PHY information specific for respective intended receivers;
generating the PHY payload comprises generating the PHY payload to include respective data specific for respective intended receivers; and
transmitting the PHY data unit comprises:
transmitting the first portion of the PHY preamble omni-directionally,
transmitting the second non-legacy signal field using beamforming so that the respective PHY information specific for respective intended receivers are respectively beamsteered to respective intended receivers, and
transmitting the PHY payload using beamforming so that the respective data specific for respective intended receivers are respectively beamsteered to the respective intended receivers.
12. The method of claim 1 , wherein when the PHY data unit is a single-user PHY data unit:
generating the first portion of the PHY preamble comprises generating each of the first non-legacy signal fields to include first PHY information;
generating the second portion of the PHY preamble comprises generating the second non-legacy signal field to include second PHY information; and
transmitting the PHY data unit comprises:
transmitting the first portion of the PHY preamble omni-directionally,
transmitting the second non-legacy signal field using beamforming, and
transmitting the PHY payload using beamforming.
13. A wireless communication device, comprising:
a wireless network interface device comprising one or more integrated circuit (IC) devices, the wireless network interface device being configured to communicate via a communication channel that comprises a plurality of sub-channels, wherein the one or more IC devices are configured to generate a first portion of a physical layer (PHY) preamble of a PHY data unit, the first portion of the PHY preamble being generated to include:
a plurality of legacy short training fields (L-STFs) spanning respective sub-channels,
a plurality of legacy long training fields (L-LTFs) spanning the respective sub-channels,
a plurality of legacy signal fields (L-SIGs) spanning the respective sub-channels, and
a plurality of first non-legacy signal fields spanning the respective sub-channels;
wherein the one or more IC devices are further configured to generate a second portion of a PHY preamble of the PHY data unit, the second portion of the PHY preamble immediately following the first portion of the PHY preamble and being generated to include:
a non-legacy short training field spanning all sub-channels in the plurality of sub-channels,
a plurality of non-legacy long training fields immediately following the non-legacy short training field, each non-legacy training field spanning all sub-channels in the plurality of sub-channels, and
a second non-legacy signal field immediately following the plurality of non-legacy long training fields, the second non-legacy signal field spanning all sub-channels in the plurality of sub-channels; and
wherein the one or more IC devices are further configured to:
generate a PHY payload of the PHY data unit that immediately follows the second non-legacy signal field, and
control the wireless network interface device to transmit the PHY data unit via the communication channel.
14. The wireless communication device of claim 13 , wherein the one or more IC devices are configured to generate two orthogonal frequency division multiplexing (OFDM) symbols that include the plurality of first non-legacy signal fields.
15. The wireless communication device of claim 14 , wherein the one or more IC devices are configured to generate the two OFDM symbols so that each non-legacy field utilizes a respective 52 OFDM tones in the two OFDM symbols.
16. The wireless communication device of claim 14 , wherein the one or more IC devices are configured to generate a single OFDM symbol that includes the second non-legacy signal field.
17. The wireless communication device of claim 16 , wherein the one or more IC devices are configured to:
generate the two OFDM symbols to each utilize a first quantity of OFDM tones; and
generating the single OFDM symbol comprises generating the single OFDM symbol to utilize a second quantity of OFDM tones different than the first quantity of OFDM tones.
18. The wireless communication device of claim 13 , the one or more IC devices are configured to generate each first non-legacy signal field to include information that indicates whether the PHY data unit is a multi-user PHY data unit.
19. The wireless communication device of claim 13 , wherein the one or more IC devices are further configured to, when the PHY data unit is a multi-user PHY data unit:
generate the second non-legacy signal field to include respective PHY information specific for respective intended receivers; and
control the wireless network interface device to transmit the second non-legacy signal field using space division multiple access (SDMA) so that the respective PHY information specific for respective intended receivers are transmitted via different respective spatial streams.
20. The wireless communication device of claim 19 , wherein the one or more IC devices are further configured to, when the PHY data unit is a multi-user PHY data unit:
generate the second non-legacy signal field to include respective modulation and coding scheme (MCS) information indicating respective MCSs for respective PHY payloads intended for respective receivers.
21. The wireless communication device of claim 19 , wherein the one or more IC devices are further configured to generate each of the first non-legacy signal fields to include common PHY information for all intended receivers.
22. The wireless communication device of claim 21 , wherein the one or more IC devices are further configured to generate each of the first non-legacy signal fields to indicate a quantity of non-legacy long training fields in the second portion of the PHY preamble.
23. The wireless communication device of claim 13 , wherein the one or more IC devices are further configured to, when the PHY data unit is a multi-user PHY data unit:
generate each of the first non-legacy signal fields to include common PHY information for all intended receivers;
generate the second non-legacy signal field to include respective PHY information specific for respective intended receivers;
generate the PHY payload to include respective data specific for respective intended receivers; and
control the wireless network interface device to:
transmit the first portion of the PHY preamble omni-directionally,
transmit the second non-legacy signal field using beamforming so that the respective PHY information specific for respective intended receivers are respectively beamsteered to respective intended receivers, and
transmit the PHY payload using beamforming so that the respective data specific for respective intended receivers are respectively beamsteered to the respective intended receivers.
24. The wireless communication device of claim 13 , wherein the one or more IC devices are further configured to, when the PHY data unit is a single-user PHY data unit:
generate each of the first non-legacy signal fields to include first PHY information;
generate the second non-legacy signal field to include second PHY information; and
control the wireless network interface device to:
transmit the first portion of the PHY preamble omni-directionally,
transmit the second non-legacy signal field using beamforming, and
transmit the PHY payload using beamforming.