核心提示：MATLAB代做|FPGA代做-OFDM在瑞利信道下的误码率源码程序...
%% Program to plot the BER of OFDM in Frequency selective channel
clc;
clear all;
close all;
N = 128; % No of subcarriers
Ncp = 16; % Cyclic prefix length
Ts = 1e-3; % Sampling period of channel
Fd = 0; % Max Doppler frequency shift
Np = 4; % No of pilot symbols
M = 2; % No of symbols for PSK modulation
Nframes = 10^3; % No of OFDM frames
D = round((M-1)*rand((N-2*Np),Nframes));
const = pskmod([0:M-1],M);
Dmod = pskmod(D,M);
Data = [zeros(Np,Nframes); Dmod ; zeros(Np,Nframes)]; % Pilot Insertion
%% OFDM symbol
IFFT_Data = (128/sqrt(120))*ifft(Data,N);
TxCy = [IFFT_Data((128-Ncp+1):128,:); IFFT_Data]; % Cyclic prefix
[r c] = size(TxCy);
Tx_Data = TxCy;
%% Frequency selective channel with 4 taps
tau = [0 1e-5 3.5e-5 12e-5]; % Path delays
pdb = [0 -1 -1 -3]; % Avg path power gains
h = rayleighchan(Ts, Fd, tau, pdb);
h.StoreHistory = 0;
h.StorePathGains = 1;
h.ResetBeforeFiltering = 1;
%% SNR of channel
EbNo = 0:5:30;
EsNo= EbNo + 10*log10(120/128)+ 10*log10(128/144); % symbol to noise ratio
snr= EsNo - 10*log10(128/144);
%% Transmit through channel
berofdm = zeros(1,length(snr));
Rx_Data = zeros((N-2*Np),Nframes);
for i = 1:length(snr)
for j = 1:c % Transmit frame by frame
hx = filter(h,Tx_Data(:,j).'); % Pass through Rayleigh channel
a = h.PathGains;
AM = h.channelFilter.alphaMatrix;
g = a*AM; % Channel coefficients
G(j,:) = fft(g,N); % DFT of channel coefficients
y = awgn(hx,snr(i)); % Add AWGN noise
%% Receiver
Rx = y(Ncp+1:r); % Removal of cyclic prefix
FFT_Data = (sqrt(120)/128)*fft(Rx,N)./G(j,:); % Frequency Domain Equalization
Rx_Data(:,j) = pskdemod(FFT_Data(5:124),M); % Removal of pilot and Demodulation
end
berofdm(i) = sum(sum(Rx_Data~=D))/((N-2*Np)*Nframes);
end
%% Plot the BER
figure;
semilogy(EbNo,berofdm,'--or','linewidth',2);
grid on;
title('OFDM BER vs SNR in Frequency selective Rayleigh fading channel');
xlabel('EbNo');
ylabel('BER');
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