CDMA扩频通信与RAKE接收机仿真程序

%chnnel slt=x_tl; %chnnel fadeing [h w]=size(slt); c_real=randn(h,3)*0.5;%乘的系数就是方差；chnnel1 chnnel2 chnnel3 c_img=randn(h,3)*0.5; c_abs=sqrt(c_real.^2+c_img.^2); c_ang=atan(c_img./c_real); %chnnel1 c1_abs=c_abs(:,1); c1_abs=hor_copy(c1_abs,Fs/Rc); c1_ang=c_ang(:,1)+1/W; c1_ang=hor_copy(c1_ang,Fs/Rc); t1=1/Fs:1/Fs:1/Rc; t1=ver_copy(t1,h); fm_ch1=slt.*c1_abs.*cos(2*pi*Fc*t1-c1_ang);%chnnel1 signal output fm_ch1_l=reshape(fm_ch1',1,h*Fs/Rc); [F_c1,f_c1]=gen_spectrum(fm_ch1_l,Fs); %chnnel2 c2_abs=c_abs(:,2); c2_abs=hor_copy(c2_abs,Fs/Rc); c2_ang=c_ang(:,2)+2/W; c2_ang=hor_copy(c2_ang,Fs/Rc); t2=1/Fs:1/Fs:1/Rc; t2=ver_copy(t2,h); fm_ch2=slt.*c2_abs.*cos(2*pi*Fc*t2-c2_ang); fm_ch2_l=reshape(fm_ch2',1,h*Fs/Rc); [F_c2,f_c2]=gen_spectrum(fm_ch2_l,Fs); %chnnel3 c3_abs=c_abs(:,3); c3_abs=hor_copy(c3_abs,Fs/Rc); c3_ang=c_ang(:,3)+3/W; c3_ang=hor_copy(c3_ang,Fs/Rc); t3=1/Fs:1/Fs:1/Rc; t3=ver_copy(t3,h); fm_ch3=slt.*c3_abs.*cos(2*pi*Fc*t3-c3_ang); fm_ch3_l=reshape(fm_ch3',1,h*Fs/Rc); [F_c3,f_c3]=gen_spectrum(fm_ch3_l,Fs); %sum fm_ch=fm_ch1+fm_ch2+fm_ch3;%每行表示每个chip fm_ch_plot=reshape(fm_ch',1,h*Fs/Rc); [F_c,f_c]=gen_spectrum(fm_ch_plot,Fs); %%%%%%%%%%%%%%%%%%%%%%%添加噪声 Es=sum(fm_ch_plot.^2); %SNR=0; En=(Es/(SpB*N))/(10^((SNR-10*log10(0.5*Fs/Rb))/10)); Noise_mesh=randn(size(fm_ch)).*sqrt(En); %Noise_mesh=zeros(size(fm_ch)); fm_ch_noised=fm_ch+Noise_mesh; fm_ch_noised_plot=reshape(fm_ch_noised',1,h*Fs/Rc); [F_c_noised,f_c_noised]=gen_spectrum(fm_ch_noised_plot,Fs); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5 %figure(2); %subplot(2,2,1); %edge=0:0.1:5; %hist(reshape(c_abs,1,h*3),edge); %title('信道衰减的直方图'); %subplot(2,2,2); %plot(t(1:2*SpB),fm_ch1_l(1:2*SpB)); %title('通过信道1后的信号波形'); %xlabel('t'); %subplot(2,2,3); %plot(t(1:2*SpB),fm_ch_plot(1:2*SpB)); %title('三条信道叠加后的信号波形'); %subplot(2,2,4); %plot(f_c,F_c); %title('三条信道叠加后的频谱'); %xlabel('Hz'); figure(3) subplot(1,2,1); plot(t(1:2*SpB),fm_ch_noised_plot(1:2*SpB)); title('带有噪声的叠加信号'); xlabel('t'); subplot(1,2,2); plot(f_c_noised,F_c_noised); title('加噪后的频谱');