simQPSK.zip_Sybol_random_simulate qpsk

% QPSK SER/BER simulation in Rayleigh fading channels clc; close all; clear all; nSims=100; % Number of simulation runs per SNR EbN0dB=0:2:20; % Eb/N0 [in dB] dataLen=100; % Number of symbols to transmit per simulation run const.s = [1 j -1 -j]; % Signal constellation const.map = [0 1 3 2]; % Bit to symbol mapping M = length(const.s); % Lenght of signal constellation Eb = 1/log2(M); % Energy per bit rndData = zeros(1,dataLen*log2(M)); % Source bits modData = zeros(1,dataLen); % Modulated Symbols gNoise = zeros(1,dataLen); % Additive white gaussian noise detData = zeros(1,dataLen); % Detected symbols detDat = zeros(1,dataLen*log2(M)); % Detected bits simBER = 0; dimSER = 0; avgBER = zeros(1,length(EbN0dB)); % Average BER avgSER = zeros(1,length(EbN0dB)); % Average SER for nSnr=1:length(EbN0dB) N0 = Eb/db2lin(EbN0dB(nSnr)); % N0 for noise sigma = sqrt(N0/2); % Noise variance (N0/2) simSER=0; simBER=0; for nIter=1:nSims rndData = round(rand(1,dataLen*log2(M))); % Generate random source bits km=1; for k=1:log2(M):dataLen*log2(M) decDat = 2*rndData(k) + rndData(k+1); % Make symbols modData(km) = const.s(find(const.map==decDat)); % Map bits-to-symbols km = km + 1; end gNoise = (sigma) * (randn(1,dataLen) + j *randn(1,dataLen)); % Generate AWGN h = sqrt(1/2) * (randn(1,dataLen) + j*randn(1,dataLen)); % Generate Rayleigh fading rxData = h.*modData + gNoise; % Make received signal km=1; for k=1:dataLen % Maximum Likelihood detection d1 = sed(h(k)*const.s(1),rxData(k)); d2 = sed(h(k)*const.s(2),rxData(k)); d3 = sed(h(k)*const.s(3),rxData(k)); d4 = sed(h(k)*const.s(4),rxData(k)); [dmin, dminI] = min([d1 d2 d3 d4]); detData(k) = const.s(dminI); switch dminI case 1 st = dec2bin(const.map(1),2); detDat(km) = str2num(st(1)); detDat(km+1) = str2num(st(2)); case 2 st = dec2bin(const.map(2),2); detDat(km) = str2num(st(1)); detDat(km+1) = str2num(st(2)); case 3 st = dec2bin(const.map(3),2); detDat(km) = str2num(st(1)); detDat(km+1) = str2num(st(2)); case 4 st = dec2bin(const.map(4),2); detDat(km) = str2num(st(1)); detDat(km+1) = str2num(st(2)); end km = km + log2(M); end simBER = simBER + sum(abs(detDat-rndData))/(dataLen*log2(M)); % Calculate BER simSER = simSER + findSER(detDat, rndData, log2(M)); % Calculate SER end avgBER(nSnr) = simBER / nSims; % Average BER avgSER(nSnr) = simSER / nSims; % Average SER prntMsg = sprintf('Done SNR = %g, @ BER = %g\n',EbN0dB(nSnr),avgBER(nSnr)); disp(prntMsg); end % Plotting semilogy(EbN0dB,avgBER,'-ro'); grid on; hold on; semilogy(EbN0dB,avgSER,'-bs'); grid on; hold on; xlabel('EbN0 [dB]'); ylabel('Average Error Probability'); title('QPSK Rayleigh fading'); legend({'BER','SER'},1);