can you help me to fix this error in code?

% Set the parameters of the simulation
N = 10000; % number of symbols to simulate
snr_range = 5:30; % range of SNR values in dB

% Generate a QPSK symbol constellation
constellation = qammod(0:3, 4);

% Create a vector of complex Gaussian noise samples with zero mean and unit variance
noise = randn(1, N) + 1i * randn(1, N);

% Loop over the SNR values
for snr_db = snr_range

    % Calculate the SNR in linear scale
    snr = 10^(snr_db/10);

    % Initialize the error counter
    errors = 0;

    % Loop over the symbols to be transmitted
    for i = 1:N

        % Select two random QPSK symbols
        s1 = constellation(randi(4));
        s2 = constellation(randi(4));

        % Generate the Alamouti coded symbol
        s = sqrt(1/2) * [s1 -s2*conj(s1); s2 conj(s1)];

        % Generate two independent Rayleigh fading coefficients
        h1 = sqrt(1/2) * (randn(1) + 1i * randn(1));
        h2 = sqrt(1/2) * (randn(1) + 1i * randn(1));

        % Calculate the received signal
        r = h1 * s(1,:) + h2 * s(2,:) + noise / sqrt(snr);

        % Decode the received signal using the Alamouti scheme
        s_hat = sqrt(1/2) * [r(1) conj(r(2)); r(2) r(1)];

        % Calculate the symbol error rate (SER) for this SNR value
        errors= errors + sum(s1 
= s_hat(1,1)) + sum(s2
=s 
h
​
 at(1,1))+sum(s2
= s_hat(1,2));
    end
% Calculate the symbol error probability (SEP) for this SNR value
sep(snr_db - min(snr_range) + 1) = errors / (N * 2);
end

% Plot the symbol error probability curve
semilogy(snr_range, sep);
xlabel('SNR (dB)');
ylabel('SEP');
title('Alamouti Scheme in Rayleigh Fading MISO Channel with QPSK');

Answer 1

[KSSV]

Replace

errors= errors + sum(s1 
= s_hat(1,1)) + sum(s2
=s 
h
​
 at(1,1))+sum(s2
= s_hat(1,2));

with

 errors= errors + sum(s1) + s_hat(1,1) + sum(s2=shat(1,1))+sum(s2=s_hat(1,2));

[Batuhan Samet Demirci]

after replacing it i got this error;

Arrays have incompatible sizes for this operation.

what should we do now sir?

the question was;

Write a MATLAB program that calculates the symbol error probability of the Alamouti scheme via numerical simulation using the QPSK symbol constellation in a Rayleigh fading MISO channel with two transmit and one receive antenna for the SNR range of 5 to 30 dB.

[Walter Roberson]

sum(s2=shat(1,1))

Provided that you have not replaced sum with a variable, that sub-expression is equivalent to

sum('s2', shat(1,1))

Are you sure you want to do that, pass in an option named s2 to sum() ? Wouldn't you prefer a comparison == instead?

Answer 2

[Image Analyst]

Read the FAQ starting from here:

https://matlab.fandom.com/wiki/FAQ#%22In_an_assignment_A(I)_=_B,_the_number_of_elements_in_B_and_I_must_be_the_same%22

There are lots of related error messages there and explains what causes them and how to avoid the problem.

[Batuhan Samet Demirci]

thanks but i coudnt still make this code work. Anyone else can help me?