LMS算法，可用于水声信道_水声信道仿真_K._水声信道LMS_用于水生信道的LMS算法_

clear; close all; % initialization %%%待发送的文字 Letter_Tr='XiaMenUniversity1234567890abcdefghijklmnopqrsthshiuywqXiamenNni'; %%%转换成二进制信息 Bit_Tr = double (reshape (dec2bin (double (Letter_Tr), 8)', 1, length (Letter_Tr) * 8)) - '0'; f0=4000; %signal frequency fc=16000; % carrier frequence fs=96000; % sampling frequency snr=5; ml=1; % modulation of level ml＝1 BPSK，ml＝2 QPSK nb=length(Bit_Tr); % number of transmiting bit t=0:1/fs:nb*(1/f0)-1/fs; N=length(t) % number of samples symlen=N/nb; %一个bit的点数 datanrz=2*Bit_Tr-1; % translate source data into NRZ code idata=datanrz(1:nb); ich=zeros(1,nb*symlen); for i=1:nb ich((i-1)*symlen+1:i*symlen)=idata(i); end for ii=1:N a(ii)=cos(2*pi*fc*t(ii)); b(ii)=sin(2*pi*fc*t(ii)); end idata1=ich.*a; qdata1=ich.*b; % idata4=idata1.*a; % qdata4=qdata1.*b; % amp=sqrt(0.5/(10^(snr/10))); %%%%%%%%%加噪声 % ss=idata1+amp*randn(size(idata1)); ss=awgn(idata1,snr); H1 = [0.05 -0.063 0.088 -0.126 -0.25 0.9047 0.25 0 0.126 0.038 0.088]; %H1=[1 -0.0509 0.0049 0.1351 0.6565 0.4899 0.1876 -0.0367]; H2=[0.3122 -0.1040 0.8908 0.3134]; befores=ss(1:1920); backs=ss(1921:length(ss)); ss1=[filter(H2,1,befores) filter(H1,1,backs)]; idata2=ss1.*a; % multiply carrier %低通滤波器 Num = remez(20,[0 0.35 0.4 1],[1 1 0 0]); idata22=filter(Num,1,idata2); qdata2=ss.*b; % multiply carrier %低通滤波器 Num1 = remez(20,[0 0.35 0.4 1],[1 1 0 0]); qdata22=filter(Num1,1,qdata2); %equalization mu=0.01;%%% 迭代步长 K=3; NN=3072; test1=ich; mse_av=zeros(1,NN-2*K); estimated_c=zeros(1,2*K+1); estimated_c(K+1)=1; for k=1:NN-2*K, y_k=idata22(k:k+2*K); z_k=estimated_c*y_k.'; e_k=test1(k)-z_k; estimated_c=estimated_c+mu*e_k*y_k; mse(k)=e_k^2; end mse_av=mse_av+mse; figure plot(mse_av); xlabel('迭代次数'); ylabel('MSE'); yy=[idata22(3073:length(idata22)) zeros(1,2*K)]; Nn=length(yy); for k=1:Nn-2*K, y_k=yy(k:k+2*K); z_k=estimated_c*y_k.'; z1(k)=z_k; end %equalization mu2=0.001; KK=10; NNN=3072; test2=qdata1; mse_av2=zeros(1,NNN-2*KK); estimated_c2=zeros(1,2*KK+1); estimated_c2(KK+1)=1; for k=1:NNN-2*KK, y_k2=qdata22(k:1:k+2*KK); z_k2=estimated_c2*y_k2.'; e_k2=test2(k)-z_k2; estimated_c2=estimated_c2+mu2*e_k2*y_k2; mse2(k)=e_k2^2; end mse_av2=mse_av2+mse2; % figure % plot(1:NNN-2*KK,mse_av2); yy=[qdata22(3073:length(idata22)) zeros(1,2*KK)]; Nn2=length(yy); for k=1:Nn2-2*KK, y_k2=yy(k:1:k+2*KK); z_k2=estimated_c2*y_k2.'; z2(k)=z_k2; end % integral and decision idata3=zeros(1,nb-128); qdata3=zeros(1,nb-128); for n=1:nb-128 ichsum(n)=sum(z1((n-1)*symlen+1:n*symlen))/(symlen); if ichsum(n)>=0 idata3(n)=1; else idata3(n)=0; end qchsum(n)=sum(z2((n-1)*symlen+1:n*symlen))/(symlen); if qchsum(n)>=0 qdata3(n)=1; else qdata3(n)=0; end end % P/S conversion demodata=zeros(1,nb-128); demodata(1:nb-128)=idata3; Bit_Tr1=Bit_Tr(129:504); num_ber=sum(abs(Bit_Tr1-idata3)) L2=length(demodata)/8; % 将解调出来的二进制信息恢复成字母 Letter_Recover=char(bin2dec(char(reshape(demodata,8,L2)'+'0')))' %calculate number of error % % figure(2) % c=1:nb; % plot(c,ichsum,'.'); figure(2) for i=1:nb-128 plot(ichsum(i),qchsum(i),'.');hold on; end xlabel('实部'); ylabel('虚部'); % plot(mse33(1:1000)); % xlabel('迭代次数'); % ylabel('MSE'); % % figure(1) % subplot(2,1,1) % plot(idata2(1:500)); % subplot(2,1,2) % plot(idata22(1:500));