本文共 4520 字，大约阅读时间需要 15 分钟。

绘制Saleh-Valenzuela信道模型

% plot_SV_model_ct.m%MIMO-OFDM Wireless Communications with MATLAB㈢   Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang%?2010 John Wiley & Sons (Asia) Pte Ltdclear, close allb002=1; % Power of 1st ray of 1st cluster N=1000 ; % Number of channelsLam=0.0233; lambda=2.5;Gam=7.4; gamma=4.3;sigma_x=3; % Standard deviation of log-normal shadowingsubplot(221)t1=0:300; p_cluster=Lam*exp(-Lam*t1); % ideal exponential pdfh_cluster=exprnd(1/Lam,1,N);                                                 % # of random number are generated[n_cluster x_cluster]=hist(h_cluster,25); % gets distributionplot(t1,p_cluster,'k'), hold onplot(x_cluster,n_cluster*p_cluster(1)/n_cluster(1),'k:');%plotting legend('Ideal','Simulation')title(['Distribution of Cluster Arrival Time, \Lambda=', num2str(Lam)])xlabel('T_m-T_{m-1} [ns]'), ylabel('p(T_m|T_{m-1})')subplot(222)t2=0:0.01:5; p_ray=lambda*exp(-lambda*t2); % ideal exponential pdfh_ray=exprnd(1/lambda,1,1000); % # of random number are generated[n_ray,x_ray]=hist(h_ray,25); % gets distributionplot(t2,p_ray,'k'), hold onplot(x_ray,n_ray*p_ray(1)/n_ray(1),'k:');   % plotting graphlegend('Ideal','Simulation')title(['Distribution of Ray Arrival Time, \lambda=', num2str(lambda)])xlabel('\tau_{r,m}-\tau_{(r-1),m} [ns]')ylabel('p(\tau_{r,m}|\tau_{(r-1),m})')subplot(223)[h,t,t0,np]= SV_model_ct(Lam,lambda,Gam,gamma,N,b002,sigma_x);stem(t(1:np(1),1),abs(h(1:np(1),1)),'ko');title('Generated Channel Impulse Response')xlabel('delay[ns]'), ylabel('Magnitude')subplot(224)X=10.^(sigma_x*randn(1,N)./20);[temp,x]=hist(20*log10(X),25);plot(x,temp,'k-'), axis([-10 10 0 120])title(['Log-normal Distribution, \sigma_X=',num2str(sigma_x),'dB'])xlabel('20*log10(X)[dB]'), ylabel('Occasion')

function [h,t,t0,np]=SV_model_ct(Lam,lam,Gam,gam,num_ch,b002,sdi,nlos)% S-V channel model% Input %  Lam      : Cluster arrival rate in GHz (avg # of clusters per nsec)%  lam      : Ray arrival rate in GHz (avg # of rays per nsec)%  Gam      : Cluster decay factor (time constant, nsec)%  gam      : Ray decay factor (time constant, nsec)%  num_ch   : number of random realizations to generate%  b002     : power of first ray of first cluster%  sdi      : Standard deviation of log-normal shadowing %                of entire impulse  response [dB]%  nlos     : Flag to specify generation of Non Line Of Sight channels% Output %  h: a matrix with num_ch columns, each column %      having a random realization of channel model (impulse response)%  t: organized as h, but holds the time instances (in nsec) of the %      paths whose signed amplitudes are stored in h%  t0: the arrival time of the first cluster for each realization%  np: the number of paths for each realization.% Thus, the k'th realization of the channel impulse response is the % sequence of (time,value) pairs given by(t(1:np(k),k),h(1:np(k),k))%MIMO-OFDM Wireless Communications with MATLAB㈢   Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang%?2010 John Wiley & Sons (Asia) Pte Ltdif nargin<8, nlos=0;  end     % LOS environmentif nargin<7, sdi=0; end % 0dBif nargin<6, b002=1; end  %  power of first ray of first clusterh_len=1000; %There must be a better estimate of # of paths than???for k=1:num_ch             % loop over number of channels   tmp_h = zeros(h_len,1);  tmp_t = zeros(h_len,1);   if nlos,  Tc = exprnd(1/Lam); % First cluster random arrival ???    else     Tc = 0;         % First cluster arrival occurs at time 0   end   t0(k) = Tc;   path_ix = 0;   while (Tc<10*Gam)  % cluster loop         % Determine Ray arrivals for each cluster     Tr=0;  %1st ray arrival defined to be time 0 relative to cluster     while (Tr<10*gam) % ray loop       brm2 = b002*exp(-Tc/Gam)*exp(-Tr/gam);  % ray power (2.20)       r = sqrt(randn^2+randn^2)*sqrt(brm2/2);        % rayleigh distributed mean power pow_bkl       h_val=exp(j*2*pi*rand)*r;  % uniform phase             path_ix = path_ix+1;      % row index of this ray       tmp_h(path_ix) = h_val;         tmp_t(path_ix) = Tc+Tr;  % time of arrival of this ray       Tr = Tr + exprnd(1/Lam); % (2.16) ???     end     Tc = Tc + exprnd(1/lam); % (2.17) ???   end   np(k)=path_ix;  % number of rays (or paths) for this realization   [sort_tmp_t,sort_ix] = sort(tmp_t(1:np(k)));  %in ascending order   t(1:np(k),k) = sort_tmp_t;   h(1:np(k),k) = tmp_h(sort_ix(1:np(k)));      % now impose a log-normal shadowing on this realization   fac = 10^(sdi*randn/20)/sqrt(h(1:np(k),k)'*h(1:np(k),k));   h(1:np(k),k) = h(1:np(k),k)*fac; % (2.21)end

转载地址：http://qjwsi.baihongyu.com/