I am getting error in qammd function, how to over come this?

M=16;

N=1024;

r=1/2;

FN=40;

generte_data=randi([0 1]), N/4*r*FN,1)

trel_code=poly2trellis(7,[171 133]]);

Coded_Data=cpnvenc(generte_data,trel_code);

QAMmod=reshape(Coded_Data,N/4,FN);

data=bi2de(QAMmod);

QAMmod1=qammod(data,M);

I am getting error like,

Error using qammd

Expected input number 1, X, to be be an array with all the values < 16

How to oercome this error?

Answer 1

[Chidvi Modala]

I assume cpnvenc is actually convenc function.

qammod(data,M) modulates input signal data by using QAM with the specified modulation order M, where data must be binary values or integers that range from 0 to (M – 1). But in the provided code, QAMmod variable is a 256*40 double vector. After converting this to decimal vector, the decimal value of data variable ranges from 0 to 2^40-1. And hence the input signal data is not satisfying the condition of being in the range from 0 to 15.