BPSK BER with OFDM in MATLAB

[hungeric]

Hello, I have some problems about plotting BPSK BER versus Eb/No with OFDM modulation.
I have written a program shown below but it doesn't work. Can anyone help me please?

clear;

fc = 1; % Carrier frequency
carrier = 4000; % Number of carrier
Ts = 1/10; % Sampling time
t = [0:Ts1-Ts)]; % Time vector
fs = 1/Ts; % Sampling frequency
Eb_No = [0:1:10]; %in dB
error = 0;


for i = 1:1:length(Eb_No)

%=====Transmitter=====
s = rand(1,carrier) > 0.5; %random 1's and 0's
st = 2*s-1; % BPSK modulation 0 --> -1, 1 --> +1
st = st';

FFT = carrier/sqrt(carrier)*fft(st);
%==========Adding Noise=========
var(i) =0.5*10^(-Eb_No(i)/10); % variance
nt = 1/sqrt(2)*[randn(1,carrier) + j*randn(1,carrier)]; %gaussian noise

AWGN =var(i)*nt; %Noise = variance x gaussian noise


FFT_noise = FFT' + AWGN;
FFT_noise =sqrt(carrier)/carrier*ifft(FFT_noise);

error(i)=0;
%Comparision
y = 2*floor(real(FFT_noise/2)) + 1;
y(find(y>1)) = +1;
y(find(y<-1)) = -1;

yt = (y+1)/2;

for ii=1:carrier
if(yt(ii)~=s(ii))
error(i)=error(i)+1; % if there is error occur, error add one
end
end

end

err_prob = error/carrier; % error probability
theory = 0.5*erfc(sqrt(10.^(Eb_No/10)));

 

[waterda]

which part of this doesn't work ?

 

[hungeric]

The part of simulation does not work...but i don't know whether it is due to the noise problem or others.

 

[Communications_Engineer]

for reference go to dsplog.com

 

[engmamj852003]

if u r still need it, please contact me with my email

maaljarrah08@eng.just.edu.jo