LDPC.zip_LDPC_Work It

% Script for drawing the EXIT chart of the UMTS turbo code, as specified % in ETSI TS 125 212 (search for it on Google if you like) % BPSK modulation over an AWGN channel is assumed. % Copyright (C) 2010 Robert G. Maunder % This program is free software: you can redistribute it and/or modify it % under the terms of the GNU General Public License as published by the % Free Software Foundation, either version 3 of the License, or (at your % option) any later version. % This program is distributed in the hope that it will be useful, but % WITHOUT ANY WARRANTY; without even the implied warranty of % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General % Public License for more details. % The GNU General Public License can be seen at http://www.gnu.org/licenses/. d_c = 4; IA_count = 11; % Choose how many points to plot in the EXIT functions block_count = 100; frame_count = 100; IAs = (0:(IA_count-1))/(IA_count-1); IE_means = zeros(1,IA_count); IE_stds = zeros(1,IA_count); % Determine each point in the EXIT functions for IA_index = 1:IA_count IEs = zeros(1,frame_count); % This runs the simulation long enough to produce smooth EXIT functions. for frame_index = 1:frame_count a = round(rand(d_c-1,block_count)); b = [a;mod(sum(a,1),2)]; apriori = generate_llrs(b,IAs(IA_index)); extrinsic = zeros(size(apriori)); for block_index = 1:block_count extrinsic(:,block_index) = check_node(apriori(:,block_index)); end IEs(frame_index) = measure_mutual_information_averaging(extrinsic); end % Store the mean and standard deviation of the results IE_means(IA_index) = mean(IEs); IE_stds(IA_index) = std(IEs); end % Create a figure to plot the results. figure; axis square; title('EXIT Function of CND with Bands'); ylabel('I_A'); xlabel('I_E'); xlim([0,1]); ylim([0,1]); hold on; % Plot the EXIT function for CND plot(IE_means,IAs,'-'); plot(IE_means+IE_stds,IAs,'--'); plot(IE_means-IE_stds,IAs,'--'); hold on; % % % % % % % clear all % % SNR = -4; % Choose the SNR % frame_count = 1000; % Choose how many frames to simulate % IA_count = 11; % Choose how many points to plot in the EXIT functions % histogram_method = 0; % Choose whether to use the histogram or the averaging method of measuring mutual information % d_c =[4,8,16,32]; % dc=[3,7,15,31]; % inputlength=[192,224,240,248]; % % % Convert from SNR (in dB) to noise power spectral density. % N0 = 1/(10^(SNR/10)); % % % % %each degree of cnd % for t=1:4 % % Calculate the MIs to use for the a priori LLRs % IAs = (0:(IA_count-1))/(IA_count-1);%11??0,0.1.???1 % IE_means = zeros(1,IA_count); % IE_stds = zeros(1,IA_count); % % Determine each point in the EXIT functions % for IA_index = 1:IA_count % % IEs = zeros(1,frame_count); % % % This runs the simulation long enough to produce smooth EXIT functions. % for frame_index = 1:frame_count % % % Generate some random bits. % a=round(rand(1,inputlength(t))) % % %insert parity bits % insert=zeros(1,length(a)/dc(t)); % suminsert=zeros(1,length(a)/dc(t)); % % k=1; % %caculate sum of each division % for j=dc(t):dc(t):length(a); % suminsert(k)=a(j)+a(j-1)+a(j-2); % k=k+1; % end % % %caculate the insert vector % for i=1:length(a)/dc(t) % insert(i)= mod(suminsert(i),2); % end % % b=reshape([reshape(a,dc(t),length(a)/dc(t));insert],1,length(a)+length(a)/dc(t)) % % % % % % % BPSK modulate them % % a_tx = -2*(a-0.5); % % c_tx = -2*(c-0.5); % % e_tx = -2*(e-0.5); % % % % % Send the BPSK signal over an AWGN channel % % a_rx = a_tx + sqrt(N0/2)*(randn(size(a_tx))+i*randn(size(a_tx))); % % c_rx = c_tx + sqrt(N0/2)*(randn(size(c_tx))+i*randn(size(c_tx))); % % e_rx = e_tx + sqrt(N0/2)*(randn(size(e_tx))+i*randn(size(e_tx))); % % % % % BPSK demodulator % % % These labels match those used in Figure 2.13 of Liang Li's nine month report. % % a_c = (abs(a_rx+1).^2-abs(a_rx-1).^2)/N0; % % c_c = (abs(c_rx+1).^2-abs(c_rx-1).^2)/N0; % % e_c = (abs(e_rx+1).^2-abs(e_rx-1).^2)/N0; % % % Generate some random a priori LLRs. % % These labels match those used in Figure 2.13 of Liang Li's nine month report. % p_a = generate_llrs(b, IAs(IA_index)); % % % Generate extrinsic LLRs from a priori LLRs % % p_e=check_node(p_a); % % % Obtain the uncoded a priori input for component decoder 1. % % % These labels match those used in Figure 2.13 of Liang Li's nine month report. % % y_a = [a_a+a_c,e_c]; % % % % Perform decoding. % % % These labels match those used in Figure 2.13 of Liang Li's nine month report. % % y_e = component_decoder(y_a,c_c); % % % Remove the LLRs corresponding to the termination bits. % % These labels match those used in Figure 2.13 of Liang Li's nine month report. % % a_e = y_e(1:length(a)); % % % Measure the mutual information % if histogram_method % IEs(frame_index) = measure_mutual_information_histogram(p_e,b); % else % IEs(frame_index) = measure_mutual_information_averaging(p_e); % end % % end % % % Store the mean and standard deviation of the results % IE_means(IA_index) = mean(IEs); % IE_stds(IA_index) = std(IEs); % end % % % Create a figure to plot the results. % figure(2); % axis square; % title('EXIT Function of CND with Bands'); % ylabel('I_A'); % xlabel('I_E'); % xlim([0,1]); % ylim([0,1]); % % hold on; % % % % % Plot the EXIT function for CND % plot(IE_means,IAs,'-'); % plot(IE_means+IE_stds,IAs,'--'); % plot(IE_means-IE_stds,IAs,'--'); % hold on; % % % % end % % %