gusucode.com > wlan工具箱matlab源码程序 > wlan/wlanexamples/helperFieldLengths.m
function out = helperFieldLengths(chanBW, format) %helperFieldLengths Get preamble field lengths for different formats % % STR = helperFieldLengths(CHANBW, FMT) returns the preamble field % lengths for the specified channel bandwidth, CHANBW, and transmission % format, FMT. Only the fields whose length can be determined based on % the channel bandwidth and format are provided. % % STR is a structure with fields storing the individual field lengths. % % CHANBW must be one of 'CBW20', 'CBW40', 'CBW80', 'CBW160'. % % FMT must be one of 'VHT', 'HT', 'NonHT'. % % Example: % str = helperFieldLengths('CBW20', 'VHT') % % See also wlanFieldIndices. % Copyright 2016 The MathWorks, Inc. %#codegen N20MHz = wlan.internal.cbwStr2Num(chanBW)/20; FFTLen = 64 * N20MHz; % FFT length for 20MHz bandwidth % Preambles are always long symLength = FFTLen * 5/4; % Set up the lengths per field fLen.LSTF = 2*symLength; fLen.LLTF = 2*symLength; fLen.LSIG = symLength; if strcmp(format, 'VHT') fLen.VHTSIGA = 2*symLength; fLen.VHTSTF = symLength; % VHTLTF length not known, not accounted for SIGB, Data out = fLen; elseif strcmp(format, 'HT') fLen.HTSIG = 2*symLength; fLen.HTSTF = symLength; % HTLTF length not known, not accounted for Data out = fLen; else % assumed NonHT % not accounted for Data out = fLen; end % [EOF]