ofdm.rar_space

%================================ % This is the simulator for OFDM. %================================ function SER = ofdm(SP) numSymbols = SP.FFTsize; % The size of the data block is equal to the FFT size. % Frequency domain version of the channel response. H_channel = fft(SP.channel,SP.FFTsize); for n = 1:length(SP.SNR), errCount = 0; % Initialize the error count. for k = 1:SP.numRun, % Generate random data block. tmp = round(rand(2,numSymbols)); tmp = tmp*2 - 1; inputSymbols = (tmp(1,:) + 1i*tmp(2,:))/sqrt(2);%QPSK % Perform OFDM modulation using IFFT. TxSamples = sqrt(SP.FFTsize)*ifft(inputSymbols); % Add CP. ofdmSymbol = [TxSamples(numSymbols-SP.CPsize+1:numSymbols) TxSamples]; % Propagate through multi-path channel. RxSamples = filter(SP.channel, 1, ofdmSymbol); % Generate AWGN with appropriate noise power. tmp = randn(2, numSymbols+SP.CPsize); complexNoise = (tmp(1,:) + 1i*tmp(2,:))/sqrt(2); noisePower = 10^(-SP.SNR(n)/10); % Add AWGN to the transmitted signal. RxSamples = RxSamples + sqrt(noisePower)*complexNoise; % Remove CP. EstSymbols = RxSamples(SP.CPsize+1:numSymbols+SP.CPsize); % Convert the received signal into frequency domain. Y = fft(EstSymbols, SP.FFTsize); % Perform channel equalization in the frequency domain. if SP.equalizerType == 'ZERO' Y = Y./H_channel; elseif SP.equalizerType == 'MMSE' C = conj(H_channel)./(conj(H_channel).*H_channel+ 10^(-SP.SNR(n)/10)); Y = Y.*C; end % Perform hard decision detection. EstSymbols = Y; EstSymbols = sign(real(EstSymbols))+ 1i*sign(imag(EstSymbols)); EstSymbols = EstSymbols/sqrt(2); % Check whether there is error. I = find((inputSymbols-EstSymbols) == 0); % Count the number of errors. errCount = errCount + (numSymbols-length(I)); end % Calculate the symbol error rate (SER). SER(n,:) = errCount / (numSymbols*SP.numRun); end