Perhaps setting random number generator will be helpful. use rng
MWs Example:
% Generate random data symbols and the 4-PSK modulated signal.
M = 4;
k = log2(M);
snr = 3;
data = randi([0 M-1],2000,1);
x = pskmod(data,M);
% Set the random number generator seed.
seed = 12345;
rng(seed);
y = awgn(x,snr);
% Compute the bit errors.
dataHat = pskdemod(y,M);
numErr1 = biterr(data,dataHat,k)
% Reset the random number generator seed.
rng(seed);
% Demodulate the PSK signal and compute the bit errors.
y = awgn(x,snr);
dataHat = pskdemod(y,M);
numErr2 = biterr(data,dataHat,k)
% Compare numErr1 to numErr2. The errors are equal even after you reset the random number generator seed.
isequal(numErr1, numErr2)
