I did a code for Rayleigh channel.I want to find the bit error rate after adding noise.Can you please help?

sampleTime = 2.0e-006; maxDopplerShift = 200; % = v*f/c [Hz] maxDelay = 0.16; K=10; L=3; M=10; %delayVec = 1.0e-006 * [0 0.04 0.08]; % delays of three-path channel delayVec = 1.0e-004 * rand([K L-1]) * maxDelay; % create avg. path delays for each user (each has 3 paths) delayVec = [zeros(K,1) delayVec]; % First path is direct path, hence 0 delay for all users %gainVec = [0 -3 -6]; gainVec = -delayVec*10^6; % average path delays [dB], decay exponentially with delay (linearly in dB) %%

% Modulation hMod = modem.pskmod(2); bitsPerFrame = M; % Number of bits transmitted per frame = M , due to BPSK modulation

S = zeros(bitsPerFrame,K); % Create data matrix for K users, each having M symbols modulated_S = zeros(bitsPerFrame,K); % Modulated data matrix nFrames = 1; % Number of frames

% Create K impulse responses for each user for i=1:K h(i) = rayleighchan(sampleTime, maxDopplerShift, delayVec(i,:), gainVec(i,:)); h(i).StoreHistory = 1; h(i).ResetBeforeFiltering = 0; % preserve the continuity of fading process for n=1:nFrames S(:,i) = randi([0 1],bitsPerFrame,1); % Create the message bits for i-th user modulated_S(:,i) = modulate(hMod, S(:,i)); % Modulate the message of i-th user into BPSK symbols Y(:,i) = filter(h(i),modulated_S(:,i)); % Apply the channel of i-th user to the modulated message channel_vis(h(i), 'Visualization', 'fr'); % Frequency response figure; plot(h(i));

    end

end % Y_dft=fft(Y,512); % k=0:511; % f=k*((2*pi)/512); % figure; % plot(f,abs(Y_dft));