why ofdmmod function error： The total number of subcarriers, including data, nulls and pilots specified, must match NFFT when my carrier number is8192

moduType = '16qam';

numCarr =8192;

M = 16；

numBits = numCarr * log2(M);

numGBCarr = numCarr/16;

gbleft = (1:numGBCarr);

gbright = ((numCarr-numGBCarr+1):numCarr);

%%%%%%%%%%%%create null

dcIdx = (numCarr/2)+1;%偶数个子载波得dc索引

nullIdx = [gbleft dcIdx gbright]';%子载波索引列

%%%%%%%%%%%%create sign

nullLen = length(nullIdx);

srcBits = randi([0,1],(numBits-nullLen)*log2(M),1);

%%%%%%%%%%%%qammod

sigOut = qammod(sign,M,"InputType","bit","UnitAveragePower",true);

%%%%%%%%%%%%cplength

CPlen = 32;

%%%%%%%%%%%%进行ofdm调制

ofdmOut = ofdmmod(sigOut,numCarr,CPlen,nullIdx);

error used ofdmmod>checkNulls (line 188)

The total number of subcarriers, including data, nulls and pilots specified, must match NFFT.

mistake ofdmmod>setup (line 147)

checkNulls(prmStr,numST);

mistake ofdmmod (line 66)

[prmStr,dataIdx] = setup(x,nfft,cplen,varargin{:});

mistake main (line 29)

ofdmOut = ofdmmod(sigOut,numCarr,CPlen,nullIdx);

Answer 1

[Muskan]

Hi,

I tried running your code, and as per my understanding of the question, it gives an error while using the "qammod" function. You can refer to the following documentation of "qammod" function for a correct implementation.

Quadrature amplitude modulation (QAM) - MATLAB qammod (mathworks.com)

Thanks