cp0802_ieeeuwb.m

IEEEuwb仿真UWB信道冲击相应；rmsds仿真UWB信道的均方根时延扩展；PDP仿真UWB信道的功率延迟剖面 rakeselector仿真RAKE接收机的路径选择 PPMcorrmask_P仿真

%
% FUNCTION 8.8 "cp0802_IEEEuwb"
%
% Generates the channel impulse response for a multi-path channel according
% to the statistical model proposed by the IEEE 802.15.SG3a
%
% 'fc' is the sampling frequency
% 'TMG' is the total multi-path gain
%
% The function returns:
% 1) the channel impulse response 'h0'
% 2) the equivalent discrete time impulse response 'hf'
% 3) the value of the observation time 'OT'
% 4) the value of the resolution time 'ts'
% 5) the value of the total multi-path gain 'X'
%
function [h0,hf,OT,ts,X]=cp0802_IEEEuwb(fc,TMG);
%-----------------------------------------------------
% Step Zero - Input parameters
%-----------------------------------------------------
OT=300e-9;                    % observation time [s]
ts=2e-9;                      % time resolution [s]

LAMBDA=0.0233*1e9;            % cluster arrival rate (1/s)
lambda=2.5e9;                 % ray arrival rate (1/s)
GAMMA=7.1e-9;                  % cluster decay factor
gamma=4.3e-9;                  % ray decay factor
sigma1=10^(3.3941/10);        % stdev of the cluster fading
sigma2=10^(3.3941/10);        % stdev of the ray fading
sigmax=10^(3/10);             % stdev of log-normal shadowing

rdt=0.001;                    % ray decay threshold
                              % rays are neglected when exp(-t/gamma)<rdt
PT=50;                        % peak threshold [dB]
                              % rays are considerd if their amplitude is withing the
                              % -PT range with respect to the peak
G=1;                          % G=1 ----------->graphical output
                              % G=0 ----------->no graphical output 
%-----------------------------------------------------
% Step One - Cluster characterization
%-----------------------------------------------------
dt=1/fc;                      % sampling time
T=1/LAMBDA;                   % average cluster inter-arrival time [s]
t=1/lambda;                   % average ray inter-arrival time [s]
i=1;
CAT(i)=0;                     % first cluster arrival time
next=0;
while next<OT;
    i=i+1;
    next=next+expinv(rand,T);
    if next<OT
        CAT(i)=next;
    end
end  %while remaining>0
%-----------------------------------------------------
% Step Two -  Path characterization
%-----------------------------------------------------
NC=length(CAT);               % number of observed clusters
logvar=(1/20)*((sigma1^2)+(sigma2^2))*log(10);
omega=1;
pc=0;                         % path counter
for i=1:NC
    pc=pc+1;
    CT=CAT(i);                % cluster time
    HT(pc)=CT;
    next=0;
    mx=10*log(omega)-(10*CT/GAMMA);
    mu=(mx/log(10))-logvar;
    a=10^((mu+(sigma1*randn)+(sigma2*randn))/20);
    HA(pc)=((rand>0.5)*2-1).*a;
    ccoeff=sigma1*randn;      % fast fading on the cluster
    while exp(-next/gamma)>rdt
        pc=pc+1;
        next=next+expinv(rand,t);
        HT(pc)=CT+next;
        mx=10*log(omega)-(10*CT/GAMMA)-(10*next/GAMMA);
        mu=(mx/log(10))-logvar;
        a=10^((mu+ccoeff+(sigma2*randn))/20);
        HA(pc)=((rand>0.5)*2-1).*a;
    end
end   % for i=1:NC

% weak peak filtering
peak=abs(max(HA));
limit=peak/10^(PT/10);
HA=HA.*(abs(HA)>(limit.*ones(1,length(HA))));

for i=1:pc
    itk=floor(HT(i)/dt);
    h(itk+1)=HA(i);
end
%-------------------------------------------------------------
% Step Three - Discrete time impulse response
%-------------------------------------------------------------
N=floor(ts/dt);
L=N*ceil(length(h)/N);
h0=zeros(1,L);
hf=h0;
h0(1:length(h))=h;
for i=1:(length(h0)/N)
    tmp=0;
    for j=1:N
        tmp=tmp+h0(j+(i-1)*N);
    end
    hf(1+(i-1)*N)=tmp;
end

% energy normalization
E_tot=sum(h.^2);
h0=h0/sqrt(E_tot);
E_tot=sum(hf.^2);
hf=hf/sqrt(E_tot);

% log-normal shadowing
mux=((10*log(TMG))/log(10))-(((sigmax^2)*log(10))/20);
X=10^((mux+(sigmax*randn))/20);
h0=X.*h0;
hf=X.*hf;
%=======================================================
% Step Four - Graphical output
%=======================================================
if G
    Tmax=dt*length(h0);
    time=(0:dt:Tmax-dt);
    
    figure(1);
    S1=stem(time,h0);
    AX=gca;
    set(AX,'FontSize',14);
    T=title('Channel Impulse Response');
    set(T,'FontSize',14);
    x=xlabel('Time [s]');
    set(x,'FontSize',14);
    y=ylabel('Ampulitude Gain');
    set(y,'FontSize',14);
    
    figure(2);
    S2=stem(time,hf);
    AX=gca;
    set(AX,'FontSize',14);
    T=title('Discrete Time Impulse Response');
    set(T,'FontSize',14);
    x=xlabel('Time [s]');
    set(x,'FontSize',14);
    y=ylabel('Amplitude Gain');
    set(y,'FontSize',14);
end