%% Generating the channel impulse response of a time-varying
%% channel according to a Jake's doppler channel model
%% Channel is the Hiperlan/2 channel model to use (1=A,2=B,3=C,5=E)
%% v is the terminal speed (m/s) with carrier frequency 5.2GHz
%%
%% October 2000. Bertrand Muquet, Sebastien Simoens, Shengli Zhou
%%
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%%%%% genh.m %%%%%
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%% %-------------------- genh.m --------------------%
%% Generating a single fading coefficient with the `sum of sinusoids'
%% Jakes Model.
%% I = frame length
%% v = terminal speed in m/s
function fadingcoeff=genh(I,v)
fc = 5.2e9; % Carrier frequency in Herz
c = 3e8; % speed of light in meters/second
fdmax=(v*fc)/c; % Maximum Doppler frequency
lambda=c/fc; % The wavelength corresponding to fc
N=100; % Number of incident waves
t=4e-6:4e-6:4e-6*I; % The time variable
% The symbol duration in HIPERLAN is 4 us
len=length(t);
theta=rand(1,N)*2*pi; % Generating the uniform phases
fd=cos(2*pi*((1:N)/N))*fdmax; % Generating uniformly spaced frequencies from
% -fdmax to +fdmax
E=exp(j.*(2*pi*fd(:)*t(:)'+repmat(theta(:),1,len)));
E=E/sqrt(N);
fadingcoeff=sum(E);
%plot(t,abs(fadingcoeff))
%xlabel('time (seconds)');ylabel('Envelope of the fading coefficient');
e-REdING. Biblioteca de la Escuela Superior de Ingenieros de Sevilla.
