编码译码基于matlab卷积码编解码仿真【含Matlab源码 3108期】.zip

% simulation of convolutional encoding / Viterbi decoding clear all; clc codeselect=4; switch codeselect case 1 Gpoly=[27 31]; case 2 Gpoly=[6 2 6; 2 4 4]; case 3 Gpoly=[4 2 6; 1 4 7]; case 4 Gpoly=[60 30 70; 14 40 74]; otherwise Gpoly=[70 30 20 40; 14 50 0 54; 4 10 74 40]; end %=============================================================== % Find key descriptors of the convolutional code %=============================================================== display_info=1; [K, M, nu, n, k, coderate, StateTable]=getcodeparameters(Gpoly); % StateTable %=============================================================== % Generate Data %=============================================================== NoBits=1000; % How many bit are to be sent EbNodBVals=[3:1:6]; BER=zeros(10,length(EbNodBVals)); BER2=BER; countSNRs=0; for Simulation=1:10, for SNR=1:length(EbNodBVals) countSNRs=countSNRs+1; NoOfBitErrors=0; TotalNoOfBits=0; TotalNoOfCodedBits=0; NoofCodedBitErrors=0; BERtemp=Inf; while NoOfBitErrors<10, m=floor(rand(1,NoBits).*2); % generate data bits %=============================================================== % Prepare data by adding leading/trailing zeros to start/end in the zero % state %=============================================================== % first add k*nu leading zeros to start from 0 state m2=[zeros(1,k.*nu) m zeros(1,k.*nu)]; NoOfLeadingAddedZeros=k.*nu; % add extra zeros to make m a multiple of k if rem(length(m2),k) > 0 % length(m) must be a multiple of k % No of input bits to encoder ExtraZeros=zeros(size(1:k-rem(length(m),k))); NoOfExtraZeros=length(ExtraZeros); m2=[m2 ExtraZeros]; % add the zeros NoOFTrailingAddedZeros=k.*nu+NoOfExtraZeros; else NoOFTrailingAddedZeros=k.*nu; end %=============================================================== % Encode Data Using Covolutional encoder %=============================================================== [c,c_bin,PathThroughTrellis]=encoder(m2,k,n,StateTable); %[c,c_bin]=encoder(m,k,n,StateTable); %If PathThroughTrellis isn't needed %=============================================================== % simulate Channel %=============================================================== % simulate BPSK modulator s=2.*c_bin-1; % noise EbNo=10.^(EbNodBVals(SNR)./10); EsNo=EbNo.*coderate; Es=1; No=Es./EsNo; sigma=sqrt(No.*2)./2; noise=sigma.*randn(size(s)); sr=s+noise; %awgn, sr= received signal % hard quantize demodulator r=zeros(size(sr)); r(sr>=0)=1; %=============================================================== %Decode Data Using Covolutional Viterbi decoder %=============================================================== [m2_est,c_bin_est,CumulatedMetric ]=decoder(r, StateTable, M, k , n); %remove trailing/leading zeros m_est=m2_est; m_est(1:NoOfLeadingAddedZeros)=[]; m_est(end- NoOFTrailingAddedZeros+1:end)=[]; NoOfBitErrors=NoOfBitErrors+length(find(m_est~=m)); TotalNoOfBits=TotalNoOfBits+length(m_est); NoofCodedBitErrors=NoofCodedBitErrors+length(find(c_bin_est~=c_bin)); TotalNoOfCodedBits=TotalNoOfCodedBits+length(c_bin); end BER(Simulation,SNR)=NoOfBitErrors./TotalNoOfBits; BER2(Simulation,SNR)=NoofCodedBitErrors./TotalNoOfCodedBits; clc disp(['Sim:' num2str(100.*(countSNRs)./(10.*length(EbNodBVals))) '% ,' ' Eb/No= ' num2str(EbNodBVals(SNR)) ' dB , BER = ' num2str(BER(Simulation,SNR))]) end end %=============================================================== % Draw the The Figures of results %============================================================== disp('Information for this code') disp('==========================') disp([ 'k = ' num2str(k) ' input bits']) disp(['n = ' num2str(n) ' output bits']) disp(['code rate = ' num2str(coderate)]) disp(['Total Number of Memory Elements M = ' num2str(sum(M))]); disp(['Total Number of States : ' num2str(2.^(sum(M)))]); disp(['Constraint Length nu : ' num2str(nu)]); disp('==========================') AverageBER=mean(BER); semilogy(EbNodBVals,AverageBER,'-*') grid on; xlabel('SNR(dB)') ylabel('BER(log)') legend('系统数据库') title('系统性能') figure(gcf)