Saleh-Valenzuela信道模型_通信

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)) if nargin<8 nlos=0; end % LOS environment if nargin<7 sdi=0; end % 0dB if nargin<6 b002=1; end % power of first ray of first cluster h_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