bpsk-ldpc.zip_LDPC BPSK_LDPC matlab_LDPC译码 MATLAB_ldpc matlab_l

% general script for non-systematic LDPC simulation % Things to Remember - Steps to follow ALWAYS !!!!!!!! % 0. This file is good for non-systematic H only (errors calculated for all n) % 1. Load H % 2. Define SNR Range % 3. Set Maximum number of iterations % 4. Set Maximum number of codeword-errors for which to run simulation % 5. Select decoder - Matlab or C-based clear all close all clc tic %get H from somewhere , change R accordingly !! load 128x256regular.mat H % load 128x256regular_v6.mat %for users of Matlab 6.5 ind=find(H==1); [r,c]=ind2sub(size(H),ind); [rows,cols]=size(H); h=sparse(H); % for use with Matlab-based LDPC Decoder n=cols; k=n-rows; % Find % 1: maximum check degree % 2: column indeces in each row which contain '1' % 3: maximum variable degree % 4: find column indeces in each row which contain '1' [max_check_degree,check_node_ones,BIGVALUE_COLS,max_variable_degree,variable_node_ones,BIGVALUE_ROWS]=one_finder(H); rand('seed',584); randn('seed',843); dB=[0:3]; % range of SNR values in dB SNRpbit=10.^(dB/10); % Eb/No conversion from dB to decimal No_uncoded=1./SNRpbit; % since Eb=1 R=k/n; % code rate No=No_uncoded./R; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% max_iter=10; %maximum number of decoder iterations %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% maximum_blockerror=30; % maximum blockerrors per SNR point %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% blockerrors=0; biterrors=0; block=0; FER=zeros(1,length(dB)); % array for Frame Error Rate BER=zeros(1,length(dB)); % array for Channel Error Rate block_array=zeros(1,length(dB)); for z=1:length(SNRpbit), % loop for testing over range of SNR values biterrors=0; blockerrors=0; block=0; while(blockerrors<maximum_blockerror) %while loop %%%%%%%%%%%%%%% u is the codeword to be transmitted %%%%%%%%%%%%%%%%%%% u=zeros(1,cols); %%all zero codeword tx_waveform=bpsk(u); sigma=sqrt(No(z)/2); rx_waveform=tx_waveform + sigma*randn(1,length(tx_waveform)); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%% Use C - based LDPC Decoder %%%%%%%%%%%%%% %%% Fastest C-based LDPC Decoder %%%% gamma_n=(4/No(z))*rx_waveform; vhat=decode_ldpc_new(max_iter,gamma_n,check_node_ones,max_check_degree,BIGVALUE_COLS-1,variable_node_ones,max_variable_degree,BIGVALUE_ROWS-1,rows,cols); uhat=vhat; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%% Slightly slower C-based LDPC Decoder %%%% % gamma_n=(4/No(z))*rx_waveform; % sg=zeros(rows,cols); % sg(ind)=gamma_n(c); % % [vhat,iteration]=decode_ldpc(No(z),H,max_iter,sg,gamma_n); % uhat=vhat; % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%% Use Matlab-based LDPC Decoder %%%%%%%%%%%%%% % % [vhat,iteration]=decode_ldpc_matlab(rx_waveform,No(z),h,rows,cols,ind,r,c,max_iter); % uhat=vhat; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Errors=zeros(1,length(vhat)); Errors(find(u~=vhat))=1; if sum(Errors)~=0 blockerrors=blockerrors+1; if rem(blockerrors,5)==0; %save statistics after every 5 blockerrors ber=biterrors/(block*n); fer=blockerrors/block; s=sprintf('%dx%d_regular_results.txt',n-k,n); fid = fopen(s,'a'); fprintf(fid,'\n'); fprintf(fid,'%s %2.1EdB\n','SNR =',dB(z)); fprintf(fid,'%s %6.3E\n','BER =',ber); fprintf(fid,'%s %6.3E\n','FER =',fer); fprintf(fid,'%s %d\n','blocks =',block); fprintf(fid,'%s %d\n','blockerrors =',blockerrors); fprintf(fid,'%s %d\n','biterrors =',biterrors); fclose(fid); end end biterrors=biterrors+sum(Errors); block=block+1; end %while loop block_array(z)=block; %counting blocks per SNR point BER(z)=biterrors/(block*n); FER(z)=blockerrors/block; fprintf(1,'\n\n Simulation finished for SNR: %d \n',dB(z)) % save results.mat dB BER FER block_array end % loop for testing over range of SNR values semilogy(dB,BER,'b-o') title('Bit Error Rate') ylabel('BER') xlabel('Eb/No (dB)') grid figure semilogy(dB,FER,'b-o') title('Frame Error Rate') ylabel('FER') xlabel('Eb/No (dB)') grid toc % Copyright (c) 2005 by Shaikh Faisal Zaheer, [email protected] % $Revision: 3.0 $ $Date: 26/12/2005 $