Return information relevant to HE-SIG-B field length
info = getSIGBLength(cfg)
Create a WLAN HE-MU-format configuration object, specifying the allocation index.
cfgHEMU = wlanHEMUConfig(0);
Generate a WLAN waveform for the specified configuration and return the PPDU field indices.
waveform = wlanWaveformGenerator(1,cfgHEMU); ind = wlanFieldIndices(cfgHEMU);
Decode the L-SIG field and obtain the OFDM information. This information is required to obtain the L-SIG length, which is used in the recovery configuration object.
lsig = waveform(ind.LSIG(1):ind.LSIG(2),:); lsigDemod = wlanHEDemodulate(lsig,'L-SIG',cfgHEMU.ChannelBandwidth); preHEInfo = wlanHEOFDMInfo('L-SIG',cfgHEMU.ChannelBandwidth);
Recover the L-SIG information bits and related information, making sure that the bits pass the parity check. 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(preHEInfo.DataIndices,:,:),0,csi);
Decode the HE-SIG-A field and recover the HE-SIG-A information 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',cfgHEMU.ChannelBandwidth); preHEInfo = wlanHEOFDMInfo('HE-SIG-A',cfgHEMU.ChannelBandwidth); [bits,failCRC] = wlanHESIGABitRecover(sigaDemod(preHEInfo.DataIndices,:,:),0,csi);
Create a WLAN recovery configuration object, specifying an HE-MU-format packet and the length of the L-SIG field.
cfg = wlanHERecoveryConfig('PacketFormat','HE-MU','LSIGLength',lsigInfo.Length);
Update the recovery configuration object with the recovered HE-SIG-A bits.
cfgUpdated = interpretHESIGABits(cfg,bits);
Return and display the HE-SIG-B information.
info = getSIGBLength(cfgUpdated); disp(info);
NumSIGBCommonFieldSamples: 80 NumSIGBSymbols: 10
info— Information relevant to HE-SIG-B field length
Information relevant to the HE-SIG-B field length, returned as a structure containing these fields.
NumHESIGBCommonFieldSamples— Number of samples in HE-SIG-B common field
Number of samples in HE-SIG-B common field, returned as a nonnegative integer.
NumHESIGBSymbols— Total number of symbols in HE-SIG-B field
Total number of symbols in HE-SIG-B field, returned as a nonnegative integer.