信息论基础与应用配书源代码.rar

M=16; % 调制阶数 EbNo=-5:-1; % 信噪比范围 frmLen=500; % 帧长 ber=zeros(size(EbNo)); enc=comm.TurboEncoder('InterleaverIndicesSource','Input port'); % 创建编码器 dec=comm.TurboDecoder('InterleaverIndicesSource','Input port', ... 'NumIterations',4); % 创建译码器 mod=comm.RectangularQAMModulator('ModulationOrder',M, ... 'BitInput',true,'NormalizationMethod','Average power'); % 创建QAM调制器 demod=comm.RectangularQAMDemodulator('ModulationOrder',M, ... 'BitOutput',true,'NormalizationMethod','Average power', ... 'DecisionMethod','Log-likelihood ratio', ... 'VarianceSource','Input port'); % 创建QAM译制器 chan=comm.AWGNChannel('EbNo',EbNo,'BitsPerSymbol',log2(M)); % 创建AWGN信道 errorRate = comm.ErrorRate; for k = 1:length(EbNo) errorStats = zeros(1,3); noiseVar = 10^(-EbNo(k)/10)*(1/log2(M)); chan.EbNo = EbNo(k); while errorStats(2) < 100 && errorStats(3) < 1e7 data = randi([0 1],frmLen,1); % 创建二进制随机数据 intrlvrInd = randperm(frmLen); % 交织 encodedData = step(enc,data,intrlvrInd); % Turbo编码 modSignal = step(mod,encodedData); % 调制 receivedSignal = step(chan,modSignal); % AWGN信道 demodSignal = step(demod,receivedSignal,noiseVar); % 解调 receivedBits = step(dec,-demodSignal,intrlvrInd); % 译码 errorStats = step(errorRate,data,receivedBits); % 统计差错 end ber(k) = errorStats(1); reset(errorRate) end semilogy(EbNo,ber,'r-o') grid xlabel('Eb/No (dB)') ylabel('误比特率') uncodedBER = berawgn(EbNo,'qam',M); % 未编码的BER hold on semilogy(EbNo,uncodedBER,'b-') legend('Turbo编码','未编码')