sefade.m

用于产生频率选择性信道,其中的一个fade.m可以用来产生瑞利衰落信道.

% Program 2-6
% sefade.m
%
% This function generates frequency selecting fading...
%
% Programmed by H. Harada
%
function[iout,qout,ramp,rcos,rsin]=sefade(idata,qdata,itau,dlvl,th,n0,itn,n1,nsamp,tstp,fd,flat)
%********************** variables *********************
% idata input Ich data
% qdata input Qch data
% iout output Ich data
% qout output Qch data
% ramp : Amplitude contaminated by fading
% rcos : Cosine value contaminated by fading
% rsin : Cosine value contaminated by fading
% itau : Delay time for each multipath fading
% dlvl : Attenuation level for each multipath fading
% th : Initialized phase for each multipath fading
% n0 : Number of waves in order to generate each
% multipath fading
% itn : Fading counter for each multipath fading
% n1 : Number of summation for direct and delayed
% waves
% nsamp : Total number of symbols
% tstp : Minimum time resolution
% fd : Maximum doppler frequency
% flat flat fading or not
% (1-flat (only amplitude is fluctuated),0-normal(phase
% and amplitude are fluctuated))
%******************************************************
iout = zeros(1,nsamp);
qout = zeros(1,nsamp);
total_attn = sum(10 .^( -1.0 .* dlvl ./ 10.0));
for k = 1 : n1
atts = 10.^( -0.05 .* dlvl(k));
if dlvl(k) == 40.0
atts = 0.0;
end
theta = th(k) .* pi ./ 180.0;
[itmp,qtmp] = delay (idata,qdata,nsamp,itau(k));
[itmp3,qtmp3,ramp,rcos,rsin] = fade (itmp,qtmp,nsamp,tstp,fd,n0(k),itn(k),flat);
iout = iout + atts .* itmp3 ./ sqrt(total_attn);
qout = qout + atts .* qtmp3 ./ sqrt(total_attn);
end
%******************** end of file *********************