channel.m

多径信道下的ofdm仿真系统

function pass_channel_data=channel(timesignal,multi,SNR,len)
%add noise
parameterinit;
load real_noise.mat real_noise;
load channel_info.mat channel_info;
%SNR=EbNo/log10(5)
   SigPow = std(timesignal);	%find the signal power
   NoiseVar = sqrt(10^(0-(SNR/10)));% add white noise 
   Noise_var=(SigPow* NoiseVar);%^2
   noisesource1=randn(1,len) ;
   noisesource2=randn(1,len);
   %load noisesource11.mat noisesource11
   %load noisesource12.mat noisesource12
   %load noisesource21.mat noisesource21
   %load noisesource22.mat noisesource22
%noise=noise_gen(Noise_var,len)
pass_channel_data=filter(channel_info,1,timesignal);
%if len==numframeguard*6
%pass_channel_data=pass_channel_data+(noisesource1+noisesource2*j).*(SigPow*NoiseVar)^2  % add white noise
%else
% pass_channel_data=pass_channel_data+(noisesource21+noisesource22*j).*(Noise_var)  % add white noise
%end
%load noise_add.mat noise_add;
pass_channel_data=pass_channel_data+real_noise'*50*Noise_var;%noise_add(1:end-1)/81*Noise_var;;