Not enough input arguments.

% function for realizing M-QAM modulation %

function simSerMQAM = mQAM(M, EsN0dB)

j = sqrt(-1); % imaginary unit %

numSim = 7*10^5; % number of simulation symbols %

k = sqrt(1/((2/3)*(M-1))); % factor for normalizing energy %

Not enough input arguments.

Error in mQAM (line 6)

k = sqrt(1/((2/3)*(M-1))); % factor for normalizing energy %

Answer 1

[KSSV]

It seems, you are striaght away running the code using run/ F5 key.

Save your code into function, with the name mQAM.m, go the directory where the file is present.

M = define your variable ;
EsN0dB = define your value ; 
% Now call the function
simSerMQAM = mQAM(M, EsN0dB) ;

[Abdullah Kamuka]

i see what you mean. defining the used variables before running it. only thing is that I havent been given M so what can i do?

[KSSV]

You must be having idea on what M and other variables are.

[KSSV]

No need to see. You need to provide inputs thats it.

[Abdullah Kamuka]

I figured out M and the code works but it doesnt give an output???

EbN0dB = [-3:14]; % multiple Eb/N0 values %

M = 16 ;

% function for realizing M-QAM modulation %

function simSerMQAM = mQAM(M, EsN0dB)

j = sqrt(-1); % imaginary unit %

numSim = 7*10^5; % number of simulation symbols %

k = sqrt(1/((2/3)*(M-1))); % factor for normalizing energy %

m = (1:sqrt(M)/2); % alphabets %

alphaMqam = [-(2*m-1) 2*m-1];

errSymsQAM = zeros(1, length(EsN0dB));

for ii = 1:length(EsN0dB)

infoSyms = randsrc(1,numSim,alphaMqam) + j*randsrc(1,numSim,alphaMqam);

infoSymsQAM = k*infoSyms; % normalization of energy to 1 %

noise = 1/sqrt(2)*(randn(1,numSim) + j*randn(1,numSim)); % white guassian noise, 0dB variance %

tranSymsQAM = infoSymsQAM + 10^(-EsN0dB(ii)/20)*noise; % additive white gaussian noise %

% demodulation %

tranSymsRe = real(tranSymsQAM)/k; % real part %

tranSymsIm = imag(tranSymsQAM)/k; % imaginary part %

% rounding to the nearest alphabet %

recSymsRe = 2*floor(tranSymsRe/2)+1;

recSymsRe(recSymsRe >max(alphaMqam)) = max(alphaMqam);

recSymsRe(recSymsRe <min(alphaMqam)) = min(alphaMqam);

% rounding to the nearest alphabet %

recSymsIm = 2*floor(tranSymsIm/2)+1;

recSymsIm(recSymsIm >max(alphaMqam)) = max(alphaMqam);

recSymsIm(recSymsIm <min(alphaMqam)) = min(alphaMqam);

demoSyms = recSymsRe + j*recSymsIm;

% counting the number of symbol errors %

errSymsQAM(ii) = size(find((infoSyms - demoSyms)),2);

end

simSerMQAM = errSymsQAM/numSim;

end

[KSSV]

It is working very fine.

EbN0dB = [-3:14]; % multiple Eb/N0 values %
M = 16 ;
simSerMQAM = mQAM(M,-3:14) ; 
simSerMQAM

simSerMQAM = 1×18

0.8102 0.7906 0.7662 0.7404 0.7103 0.6754 0.6350 0.5891 0.5372 0.4806 0.4186 0.3534 0.2868 0.2219 0.1628 0.1088 0.0679 0.0369

% function for realizing M-QAM modulation %
function simSerMQAM = mQAM(M, EsN0dB)
j = sqrt(-1); % imaginary unit %
numSim = 7*10^5; % number of simulation symbols %
k = sqrt(1/((2/3)*(M-1))); % factor for normalizing energy %
m = (1:sqrt(M)/2); % alphabets %
alphaMqam = [-(2*m-1) 2*m-1];
errSymsQAM = zeros(1, length(EsN0dB));
for ii = 1:length(EsN0dB)
    infoSyms = randsrc(1,numSim,alphaMqam) + j*randsrc(1,numSim,alphaMqam);
    infoSymsQAM = k*infoSyms; % normalization of energy to 1 %
    noise = 1/sqrt(2)*(randn(1,numSim) + j*randn(1,numSim)); % white guassian noise, 0dB variance %
    tranSymsQAM = infoSymsQAM + 10^(-EsN0dB(ii)/20)*noise; % additive white gaussian noise %
    % demodulation %
    tranSymsRe = real(tranSymsQAM)/k; % real part %
    tranSymsIm = imag(tranSymsQAM)/k; % imaginary part %
    % rounding to the nearest alphabet %
    recSymsRe = 2*floor(tranSymsRe/2)+1;
    recSymsRe(recSymsRe >max(alphaMqam)) = max(alphaMqam);
    recSymsRe(recSymsRe <min(alphaMqam)) = min(alphaMqam);
    % rounding to the nearest alphabet %
    recSymsIm = 2*floor(tranSymsIm/2)+1;
    recSymsIm(recSymsIm >max(alphaMqam)) = max(alphaMqam);
    recSymsIm(recSymsIm <min(alphaMqam)) = min(alphaMqam);
    demoSyms = recSymsRe + j*recSymsIm;
    % counting the number of symbol errors %
    errSymsQAM(ii) = size(find((infoSyms - demoSyms)),2);
end
simSerMQAM = errSymsQAM/numSim;
end

[Abdullah Kamuka]

ahhhh i see

i didnt have these lines thats why

simSerMQAM = mQAM(M,-3:14) ;

simSerMQAM

i got the values now.

what about this error?

Unable to perform assignment because the left and right sides have a different number of elements.

Error in mQAM34 (line 35)

recPhase(find(recPhase <0)) = recPhase(find(recPhase >0)) + 2*pi;

[Torsten]

Seems that

find(recPhase <0)

and

find(recPhase >0)

have a different number of elements.

Or is it just a typing error with the < and > signs ?