wlanNonHTOFDMInfo

Get OFDM information for non-HT transmission

Description

example

info = wlanNonHTOFDMInfo(field) returns info, a structure containing orthogonal frequency-division multiplexing (OFDM) information for the input field in a non-high-throughput (non-HT) transmission.

Examples

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Get and display the OFDM information for the non-HT-Data field.

info = wlanNonHTOFDMInfo('NonHT-Data');
disp(info);
                 FFTLength: 64
                  CPLength: 16
            NumSubchannels: 1
                  NumTones: 52
          ActiveFFTIndices: [52x1 double]
    ActiveFrequencyIndices: [52x1 double]
               DataIndices: [48x1 double]
              PilotIndices: [4x1 double]

Perform OFDM demodulation of the L-LTF in a non-HT transmission, then extract the data and pilot subcarriers.

Generate a WLAN waveform for a non-HT transmission.

cfg = wlanNonHTConfig;
bits = [1; 0; 0; 1];
waveform = wlanWaveformGenerator(bits,cfg);

Obtain the field indices and extract the L-LTF.

ind = wlanFieldIndices(cfg);
rx = waveform(ind.LLTF(1):ind.LLTF(2),:);

Perform OFDM demodulation on the L-LTF.

sym = wlanLLTFDemodulate(rx,cfg);

Get the OFDM information, then extract the data and pilot subcarriers.

info = wlanNonHTOFDMInfo('L-LTF');
data = sym(info.DataIndices,:,:);
pilots = sym(info.PilotIndices,:,:);

Input Arguments

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Field for which to return OFDM information, specified as one of these values.

  • 'L-LTF' – Return OFDM information for the legacy long training field (L-LTF).

  • 'L-SIG' – Return OFDM information for the legacy signal (L-SIG) field.

  • 'NonHT-Data' – Return OFDM information for the non-HT-Data field.

Data Types: char | string

Output Arguments

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OFDM information, returned as a structure containing these fields.

NameValuesDescriptionData Types
FFTLengthPositive integerLength of the fast Fourier transform (FFT)double
CPLengthPositive integer

Cyclic prefix length, in samples

double
NumTonesNonnnegative integer

Number of active subcarriers

double
NumSubchannelsPositive integerNumber of 20-MHz subchannelsdouble
ActiveFrequencyIndicesColumn vector of integers in the interval [-FFTLength/2, (FFTLength/2 – 1)]Indices of active subcarriers. Each element of this field is the index of an active subcarrier, such that the direct current (DC) or null subcarrier is at the center of the frequency band.double
ActiveFFTIndicesColumn vector of integers in the interval [1, FFTLength]Indices of active subcarriers within the FFTdouble
DataIndicesColumn vector of integers in the interval [1, NumTones]Indices of data within the active subcarriersdouble
PilotIndicesColumn vector of integers in the interval [1, NumTones]Indices of pilots within the active subcarriersdouble

Data Types: struct

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

See Also

Functions

Objects

Introduced in R2019a