det_mod_loo.m

jakes模型

%--------------------------------------------------------------------
% det_mod_Loo.m -----------------------------------------------------
%
% Program for the simulation of modified Loo processes.
%
% Used m-files: parameter_Jakes.m, parameter_Gauss.m, Mu_i_t.m
%--------------------------------------------------------------------
% rho_t=det_mod_Loo(N_1,N_2,N_3,sigma_1_2,kappa_1,sigma_2_2,...
% kappa_2,f_max,sigma_3,m_3,f_rho,...
% theta_rho,f_c,T_s,T_sim,PLOT)
%--------------------------------------------------------------------
% Explanation of the input parameters:
%
% N_1, N_2, N_3: number of harmonic functions of the real determi-
% nistic Gaussian processes nu_1(t), nu_2(t), and
% nu_3(t), respectively
% sigma_1_2: average power of the real deterministic Gaussian
% process nu_1(t)
% kappa_1: frequency ratio f_min/f_max (0<=kappa_0<=1) of nu_1(t)
% sigma_2_2: average power of the real deterministic Gaussian
% process nu_2(t)
% kappa_2: frequency ratio f_min/f_max (0<=kappa_0<=1) of nu_2(t)
% f_max: maximum Doppler frequency
% sigma_3: square root of the average power of the real deterministic
% Gaussian process nu_3(t)
% m_3: average value of the third real deterministic Gaussian
% process mu_3(t)
% f_rho: Doppler frequency of the LOS component m(t)
% theta_rho: phase of the LOS component m(t)
% f_c: 3-dB-cut-off frequency
% T_s: sampling interval
% T_sim: duration of the simulation
% PLOT: plot of the time-domain signal rho(t), if PLOT==1
function rho_t=det_mod_Loo(N_1,N_2,N_3,sigma_1_2,kappa_1,...
         sigma_2_2,kappa_2,f_max,sigma_3,m_3,f_rho,theta_rho,f_c,T_s,T_sim,PLOT)

     if nargin==15,
   PLOT=0;
end

sigma_1=sqrt(sigma_1_2);
sigma_2=sqrt(sigma_2_2);

N_1_s=ceil(N_1/(2/pi*asin(kappa_1)));
[f1,c1,th1]=parameter_Jakes('es_j',N_1_s,sigma_1_2,f_max,'rand',0);
f1 =f1(1:N_1);
c1 =c1(1:N_1)/sqrt(2);
th1=th1(1:N_1);

N_2_s=ceil(N_2/(2/pi*asin(kappa_2)));
[f2,c2,th2]=parameter_Jakes('es_j',N_2_s,sigma_2_2,f_max,'rand',0);
f2 =f2(1:N_2);
c2 =c2(1:N_2)/sqrt(2);
th2=th2(1:N_2);

[f3,c3,th3]=parameter_Gauss('es_g',N_3,1,f_max,f_c,'rand',0);
gaMma=(2*pi*f_c/sqrt(2*log(2)))^2;
f3(N_3)=sqrt(gaMma*N_3/(2*pi)^2-sum(f3(1:N_3-1).^2));

N=ceil(T_sim/T_s);
t=(0:N-1)*T_s;

arg=2*pi*f_rho*t+theta_rho;

RHO_t=exp(Mu_i_t(c3,f3,th3,T_s,T_sim)*sigma_3+m_3);

rho_t=abs(Mu_i_t(c1,f1,th1,T_s,T_sim)+Mu_i_t(c2,f2,th2,T_s,T_sim)+RHO_t.*cos(arg)+...
       j*(Mu_i_t(c1,f1,th1-pi/2,T_s,T_sim)-Mu_i_t(c2,f2,th2-pi/2,T_s,T_sim)+RHO_t.*sin(arg)));
   
if PLOT==1,
   plot(t,20*log10(rho_t),'b-',t,20*log10(RHO_t),'y--')
   xlabel('t (s)')
   ylabel('20 log rho(t)')
end