www.gusucode.com > DS-cdma仿真matlab程序 > code8/cdma/final11_extra.m
%********************************************************************** % This program computes the average BER of a DS-SS/BPSK % communication system with binary BCH code in the AWGN channel % % AUTHOR: Wenbin Luo % DATE : 04/28/01 % % final11_extra.m % %********************************************************************** %function Plot_Pe = final11_extra() clear all; %close all; format long; %set up the threshold Vt Vt = 0; Plot_Pe = []; N = 16; x_num = 2500; plot_EbNo = -20:2:10; for EbNo = -20:2:10, %convert back from dB Eb_No = EbNo; %dB Eb_No = 10.^(Eb_No/10); %assume No = 2; No = 2; Eb = No * Eb_No; %calculate power p Tc = 1; Ts = N * Tc; p = Eb / Ts; %generate BPSK symbols randomly with value +1 or -1 x = bingen(x_num); x_org = x; %adds error-correcting code enc_N = 15; enc_K = 5; %7/4 or 15/5 x(find(x < 0)) = 0; x = encode(x,enc_N,enc_K,'bch'); x = x'; x(find(x == 0)) = -1; %DS-SS modulate symbols with user code c = bingen(N); y = ds_mod(c(:),x); %scale by appropriate power factor y = sqrt(p)*y; %add AWGN to signal y = awgn(y,1); %DS-SS demodulate symbols with user code x_de = ds_demod(c(:),y); %decision x_de(find(x_de < 0)) = -1; x_de(find(x_de >=0)) = 1; %decode error-correcting code x_de(find(x_de < 0)) = 0; x_de = decode(x_de,enc_N,enc_K,'bch'); x_de = x_de'; x_de(find(x_de == 0)) = -1; %------------------------------------- Pe = length(find(x_org - x_de))/x_num; Plot_Pe = [Plot_Pe Pe]; end %end for EbNo %--------------------------------------------- %return; %--------------------------------------------- %display the calculated Pd and Pfa Plot_Pe %plot Pe versus Eb/No semilogy(plot_EbNo,Plot_Pe,'bo-') xlabel('Eb/No (dB)') ylabel('BER') s=sprintf('BER versus Eb/No with binary BCH code in the AWGN channel'); title(s);