interpretHESIGBCommonBits
Interpret HE-SIG-B common field bits and update HE transmission parameters
Since R2020b
Syntax
Description
updates high-efficiency multi-user (HE MU) transmission parameters cfgUpdated
= interpretHESIGBCommonBits(cfg
,bits
,status
)cfg
by interpreting bits
, the recovered HE-SIG-B common field bits, and
status
, the result of content channel decoding. The function
populates the properties of cfg
that are relevant to the HE-SIG-B
common field and returns updated HE MU transmission parameters
cfgUpdated
. If you use this syntax and the function cannot interpret
the recovered HE-SIG-B common field bits, the function does not return an output and issues
an error message.
[
returns the result of HE-SIG-B common field interpretation. If you use this syntax and the
function cannot interpret the recovered HE-SIG-B common field bits, the function returns the
cfgUpdated
,failInterpretation
] = interpretHESIGBCommonBits(cfg
,bits
,status
)failInterpretation
output as 1
and
cfgUpdated
as cfg
without updating any property
values.
Examples
Update HE MU Recovery Configuration Object
Update a WLAN HE recovery configuration object by interpreting recovered HE-SIG-A and HE-SIG-B information bits.
Generate HE MU Waveform
Create a WLAN HE MU configuration object, setting the allocation index to 0
.
cfgHEMU = wlanHEMUConfig(0);
Generate a WLAN waveform and PPDU field indices for the specified configuration.
waveform = wlanWaveformGenerator(1,cfgHEMU); ind = wlanFieldIndices(cfgHEMU);
Recover L-SIG Bits
Create a WLAN recovery configuration object, specifying an HE MU packet format and the length of the L-SIG field.
cfg = wlanHERecoveryConfig('PacketFormat','HE-MU','ChannelBandwidth','CBW20');
Decode the L-SIG field and obtain the orthogonal frequency-division multiplexing (OFDM) information. The recovery configuration object requires this information to obtain the L-SIG length.
lsig = waveform(ind.LSIG(1):ind.LSIG(2)); lsigDemod = wlanHEDemodulate(lsig,'L-SIG',cfg.ChannelBandwidth); info = wlanHEOFDMInfo('L-SIG',cfg.ChannelBandwidth); lsigDemod = lsigDemod(info.DataIndices,:);
Recover the L-SIG bits and related information, making sure that the bits pass the parity check, and update the recovery configuration object with the L-SIG length. For this example we assume a noiseless channel. For more realistic results you can pass the waveform through an 802.11ax™ channel model by using the wlanTGaxChannel
System object™ and work with the received waveform.
csi = ones(52,1); [lsigBits,failCheck,lsigInfo] = wlanLSIGBitRecover(lsigDemod,0,csi); cfg.LSIGLength = lsigInfo.Length;
Update Recovery Configuration Object with HE-SIG-A Bits
Decode the HE-SIG-A field and recover the HE-SIG-A bits, ensuring that the bits pass the cyclic redundancy check (CRC).
siga = waveform(ind.HESIGA(1):ind.HESIGA(2));
sigaDemod = wlanHEDemodulate(siga,'HE-SIG-A',cfg.ChannelBandwidth);
sigaDemod = sigaDemod(info.DataIndices,:);
[sigaBits,failCRC] = wlanHESIGABitRecover(sigaDemod,0,csi);
disp(failCRC)
0
Update the recovery configuration object with the recovered HE-SIG-A bits. Display the updated object. A property value of -1
or 'Unknown'
indicates an unknown or undefined property, which can be updated after decoding the HE-SIG-B common and user fields of the HE MU packet.
[cfg,failInterpretation] = interpretHESIGABits(cfg,sigaBits)
cfg = wlanHERecoveryConfig with properties: PacketFormat: 'HE-MU' ChannelBandwidth: 'CBW20' LSIGLength: 878 SIGBCompression: 0 SIGBMCS: 0 SIGBDCM: 0 NumSIGBSymbolsSignaled: 10 STBC: 0 LDPCExtraSymbol: 1 PreFECPaddingFactor: 1 PEDisambiguity: 0 GuardInterval: 3.2000 HELTFType: 4 NumHELTFSymbols: 1 UplinkIndication: 0 BSSColor: 0 SpatialReuse: 0 TXOPDuration: 127 HighDoppler: 0 AllocationIndex: -1 NumUsersPerContentChannel: -1 RUTotalSpaceTimeStreams: -1 RUSize: -1 RUIndex: -1 STAID: -1 MCS: -1 DCM: -1 ChannelCoding: 'Unknown' Beamforming: -1 NumSpaceTimeStreams: -1 SpaceTimeStreamStartingIndex: -1
failInterpretation = logical
0
Update Recovery Configuration Object with HE-SIG-B Common Field Bits
Decode the HE-SIG-B common field, ensuring that all content channels pass the CRC.
len = getSIGBLength(cfg);
sigbCommon = waveform(double(ind.HESIGA(2))+(1:len.NumSIGBCommonFieldSamples),:);
sigbCommonDemod = wlanHEDemodulate(sigbCommon,'HE-SIG-B',cfgHEMU.ChannelBandwidth);
sigbCommonDemod = sigbCommonDemod(info.DataIndices);
[sigbCommonBits,status,~] = wlanHESIGBCommonBitRecover(sigbCommonDemod,0,csi,cfg);
disp(status)
Success
Update the recovery configuration object with the recovered HE-SIG-B common field bits and display the updated object. A field returned as -1
or 'Unknown'
indicates an unknown or undefined property value, which can be updated after decoding the HE-SIG-B user field of the HE MU packet.
[cfg,failInterpretation] = interpretHESIGBCommonBits(cfg,sigbCommonBits,status)
cfg = wlanHERecoveryConfig with properties: PacketFormat: 'HE-MU' ChannelBandwidth: 'CBW20' LSIGLength: 878 SIGBCompression: 0 SIGBMCS: 0 SIGBDCM: 0 NumSIGBSymbolsSignaled: 10 STBC: 0 LDPCExtraSymbol: 1 PreFECPaddingFactor: 1 PEDisambiguity: 0 GuardInterval: 3.2000 HELTFType: 4 NumHELTFSymbols: 1 UplinkIndication: 0 BSSColor: 0 SpatialReuse: 0 TXOPDuration: 127 HighDoppler: 0 AllocationIndex: 0 NumUsersPerContentChannel: 9 RUTotalSpaceTimeStreams: -1 RUSize: -1 RUIndex: -1 STAID: -1 MCS: -1 DCM: -1 ChannelCoding: 'Unknown' Beamforming: -1 NumSpaceTimeStreams: -1 SpaceTimeStreamStartingIndex: -1
failInterpretation = logical
0
Update Recovery Configuration Object with HE-SIG-B User Field Bits
Decode the HE-SIG-B user field, ensuring that all users pass the CRC.
sigbUser = waveform(ind.HESIGB(1):ind.HESIGB(2));
sigbUserDemod = wlanHEDemodulate(sigbUser,'HE-SIG-B',cfgHEMU.ChannelBandwidth);
sigbUserDemod = sigbUserDemod(info.DataIndices,:);
[sigbUserBits,failCRC,~] = wlanHESIGBUserBitRecover(sigbUserDemod,0,csi,cfg);
disp(failCRC)
0 0 0 0 0 0 0 0 0
Update the recovery configuration object with the recovered HE-SIG-B user field bits.
[user,failInterpretation] = interpretHESIGBUserBits(cfg,sigbUserBits,failCRC);
Display the results of interpretation and the third element of the user
output.
disp(failInterpretation)
0 0 0 0 0 0 0 0 0
disp(user{3})
wlanHERecoveryConfig with properties: PacketFormat: 'HE-MU' ChannelBandwidth: 'CBW20' LSIGLength: 878 SIGBCompression: 0 SIGBMCS: 0 SIGBDCM: 0 NumSIGBSymbolsSignaled: 10 STBC: 0 LDPCExtraSymbol: 1 PreFECPaddingFactor: 1 PEDisambiguity: 0 GuardInterval: 3.2000 HELTFType: 4 NumHELTFSymbols: 1 UplinkIndication: 0 BSSColor: 0 SpatialReuse: 0 TXOPDuration: 127 HighDoppler: 0 AllocationIndex: 0 NumUsersPerContentChannel: 9 RUTotalSpaceTimeStreams: 1 RUSize: 26 RUIndex: 3 STAID: 0 MCS: 0 DCM: 0 ChannelCoding: 'LDPC' Beamforming: 0 NumSpaceTimeStreams: 1 SpaceTimeStreamStartingIndex: 1
Input Arguments
cfg
— HE MU transmission parameters before interpretation of HE-SIG-B common field bits
wlanHERecoveryConfig
object
HE MU transmission parameters before interpretation of HE-SIG-B common field bits,
specified as a wlanHERecoveryConfig
object.
bits
— Recovered HE-SIG-B common field bits
binary-valued matrix
Recovered HE-SIG-B common field bits, specified as binary-valued matrix whose size depends on the channel bandwidth of the transmission.
Channel Bandwidth | Size of bits |
---|---|
20 MHz | 18-by-1 |
40 MHz | 18-by-2 |
80 MHz | 27-by-2 |
160 MHz | 43-by-2 |
Data Types: int8
status
— Result of content channel decoding
character vector
Result of content channel decoding, specified as one of these values.
'Success'
– All content channels passed the cyclic redundancy check (CRC).'ContentChannel1Fail'
– Content channel 1 failed the CRC, and the number of HE-SIG-B symbols signaled in the HE-SIG-A field is less than 16.'ContentChannel2Fail'
– Content channel 2 failed the CRC, and the number of HE-SIG-B symbols signaled in the HE-SIG-A field is less than 16.'UnknownNumUsersContentChannel1'
– Content channel 1 failed the CRC, and the number of HE-SIG-B symbols signaled in the HE-SIG-B field is 16.'UnknownNumUsersContentChannel2'
– Content channel 2 failed the CRC, and the number of HE-SIG-B symbols signaled in the HE-SIG-B field is 16.'AllContentChannelCRCFail'
– All content channels failed the CRC.
The value of this input depends on the result of the cyclic redundancy
check (CRC) per content channel and the number of HE-SIG-B symbols signaled in the
HE-SIG-A field. for more information, see wlanHESIGBCommonBitRecover
.
Data Types: char
| string
Output Arguments
cfgUpdated
— Updated HE MU transmission parameters
wlanHERecoveryConfig
object
Updated HE MU transmission parameters, returned as a wlanHERecoveryConfig
object. The function updates the properties of this object in accordance with the
recovered HE-SIG-B common field bits bits
. For information on the
contents of the HE-SIG-B field, see [1].
failInterpretation
— Result of HE-SIG-B common field interpretation
0
| 1
Result of HE-SIG-B common field interpretation, returned as a logical
0
or 1
. A value of 1
indicates that the function cannot interpret the recovered HE-SIG-B common field bits. A
value of 0
indicates that the function successfully interprets the
HE-SIG-B common field bits.
Data Types: logical
References
[1] IEEE® Std 802.11ax™-2021 (Amendment to IEEE Std 802.11™-2020). “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. Amendment 1: Enhancements for High Efficiency WLAN.” IEEE Standard for Information Technology — Telecommunications and Information Exchange between Systems. Local and Metropolitan Area Networks — Specific Requirements.
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Version History
Introduced in R2020b
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