802.11ax Signal Configuration

This topic applies to the following Generation Mode:

• HE MU PPDU

1. General Settings

Space Time Block Coding

Enable/disable space time block coding. STBC encoder spreads constellation points from Nss spatial stream into Nsts space-time streams using a space-time block code. STBC is allowed only with single spatial stream and two space-time streams.

LTF Symbol Interval Mode

Select the Symbol interval (with guard interval) for the HE-LTF field. The current combinations are 2x HE-LTF + 0.8 µs, 2x HE-LTF + 1.6 µs ,4x HE-LTF + 3.2 µs, and 4x HE-LTF + 0.8 µs.

Number of HE-LTFs (Nheltf)

Specify the number of HE-LTFs.

Number of Total Space Time Streams (Nsts,total)

This is information indicating the total number of space time streams , which is equal to the sum of the Nsts for each user.

Number of Transmit Chains (Ntx)

Set the number of transmit chains. When the number of instruments is more than 1 and the Channel State is Off, it automatically equals to the number of instruments and can't be changed, otherwise, it's editable.

Packet Extension a factor

Set or Get the Packet Extension a factor.

Maximum Packet Extension Duration

Set or Get the Maximum Packet Extension Duration for Current PPDU.

2. HE-SIG-A Settings

Link

Indicates whether the frame is Uplink or Downlink. The field is set to DL for TDLS.

BSS Color

Get or Set the Base station identifier.The BSS Color field is an identifier of the BSS.

TXOP Duration

Set or Get the remaining time duration in the current TXOP. Set to 8449 μs to indicate no duration information. Set to value other than 8449 μs to indicate the duration information for NAV setting and protection of the TXOP. When the value ranges from 0 to 504 μs, the granularity is 8 μs. When the value ranges from 512 to 8448 μs, the granularity is 128 μs.

Spatial Reuse

Indication of CCA Level, Interference Level accepted, TX Power.

Doppler Indication

Indicate a PPDU with enhanced immunity to Doppler.

3. HE-SIG-B Settings

SIG-B Compression Mode

This compression bit is carried in the HE-SIG-A MU format to differentiate full BW MU-MIMO from OFDMA MU PPDU. When Enable indicate full band MU-MIMO.

Number of SIG-B Symbols

Set the number of HE-SIG-B symbols. Its maximum value is 20, and minimum value is 1. The default value is 1.

Dual Carrier Modulation of SIG-B

Enable/disable dual sub-carrier modulation for payload of HE-SIG-B.

SIG-B MCS Index

Select the MCS Index of HE-SIG-B. Only MCS0~MCS5 can be selected.

Number of Full BW MU-MIMO Users

Get or Set the number of MU-MIMO users when SIGB compression mode is enabled.

4. RU Arrangement Settings

The 1st 20Mhz Band Allocation Index

Gets or sets the RU allocation signalling for the 1st 20Mhz Band.

For 40M bandwidth, the following two parameter names are available:

• The 1st 20Mhz Band Allocation Index
• The 2nd 20Mhz Band Allocation Index

For 80M bandwidth the two parameter name are available:

• The 1st 2.0Mhz Band Allocation Index
• The 2nd 20Mhz Band Allocation Index
• The 3rd 20Mhz Band Allocation Index
• The 4th 20Mhz Band Allocation Index

Band #

The band frequency index of current RU configuration.

State

Resource unit (RU) state.

RU Size

Select the resource unit (RU) size for current user, which could be 26, 52, 106, 242, 484, 996, or 2*996 sub carriers. Note that the instrument must have at least the equivalent bandwidth to allow the waveform to be successfully transmitted.

User Number

Get the number of users for current resource unit.

Nsts,total

Displays the Number of Space Time Streams (Nsts,u) of current user. When STBC is OFF, it is equal Nss,u. When STBC is ON, it equals 2 times Nss,u.