SIG Field
2 symbols, each modulated using Q-BPSK, same as in 11n green field preamble.
48 data tones occupying tones {-26:26} within each 2MHz subband, and modulated using 11n/11ac MCS0. [12/308r2, Motion1]
Data tones are mapped to multiple space-time streams using the first column of P matrix—the same as in 11n GF preamble.
![](data:image/png;base64,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)
R.3.2.1.1.B: MU packets use a “mixed-mode” format shown below:
This frame format can also be used for SUBF [12/373r0]
Omni Portion
LTF1 and SIG field both have 52 data tones.
Different from the legacy portion of 11n MM preamble and 11ac preamble.
STF/LTF1/SIG fields applies single stream in each subcarrier (without the 1st column P matrix mapping as seen in SU preamble), similar to the legacy portion of 11n MM preamble and 11ac preamble.
![](data:image/png;base64,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)
SIG field subfield definition is different from SU, and the two symbols in SIG field are modulated using QBPSK and BPSK respectively
Refer to R.3.2.1.1.C.
MU Portion
MU-STF is the same as (downclocked) 11ac VHT-STF.
Modulation flows of MU-STF, MU-LTFs, and SIGB are the same as 11ac MU packets.
i.e. all streams for all users are trained by MU-LTFs.
Up to 4 space-time stream across all users (refer to [11/1275r1]).
R.3.2.1.1.C: SU/MU autodetection
For >=2MHz SU and MU packets, the 1st SIG symbol is always QBPSK
Used for autodetection between 1MHz and 2MHz preamble—refer to [11/1482r3].
The 2nd SIG symbol is used for autodetection between SU and MU packets.
R.3.2.1.1.D: 4/8/16 MHz frame format
For 4MHz, 8MHz, and 16MHz packets, the STF/LTF/SIG field designs are similar to 11ac 40/80/160MHz.
STF/SIG fields are repeated and phase rotated (same as in 11ac) over each 2MHz subband.
[12/308r2, Motion3]R.3.2.1.1.E: SIG field content for >=2MHz
2MHz SIGA [12/308r2, Motion2]
Recall that SU and MU are differentiated by autodetection
|
SU
|
MU
|
Length / Duration
|
9
|
9
|
MCS
|
4
|
|
BW
|
2
|
2
|
Aggregation
|
1
|
|
STBC
|
1
|
1
|
Coding
|
2
|
5
|
SGI
|
1
|
1
|
GID
|
|
6
|
Nsts
|
2
|
8
|
PAID
|
129
|
|
Ack Indication
|
2
|
2
|
Reserved
|
57
|
46
|
CRC
|
4
|
4
|
Tail
|
6
|
6
|
Total
|
48
|
48
|
LENGTH/DURATION: in num of symbols when aggregation is 1, is in num of bytes when aggregation is 0, Mandate AMPDU for packet sizes > 511 bytes and for MU.
STBC: Same as in 11ac (Alamouti code on all streams or none).
Nsts: for SU (2 bits), represents 1~4 STS; for MU (8 bits), represents 0~3 STS per user for the 4 users.
Coding: for SU 1 bit indicates BCC/LDPC, the other bits indicates additional symbol during LDPC encoding process; for MU, 4 bits indicates BCC/LDPC of 4 clients, and 1 bit indicates whether additional symbols happens for any user when encoding LDPC (same as 11ac).
MCS: for SU, 4 bit MCS index; for MU, reuse 3 bits for BCC/LDPC indicator for users 2~4—similar as in 11ac VHTSIGA.
Aggregation: Mainly applicable for SU, reserved for MU.
CRC: 4 bits of CRC should be enough as shown in the Appendix
GID: 6-bit GID as in 11ac for MU, not needed for SU.
PAID: 9 bits PAID, not needed for MU.
Ack Indication: 2 bits [refer to R.3.2.1.C]
2MHz SIGB (MU)
|
BW (MHz)
|
|
2
|
4
|
8
|
16
|
MCS
|
4
|
4
|
4
|
4
|
Tail
|
6
|
6
|
6
|
6
|
CRC
|
8
|
8
|
8
|
8
|
Reserved
|
8
|
9
|
11
|
11
|
Total
|
26
|
27
|
29
|
29
|
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