pr8_11.m

Spread Spectrum and CDMA Principles and Applications 书籍和代码

%Problem 8.11;
%optimizing average serial search time;

clear all; close all;
Pc=0.999; %specify probability of correct search;
Ts=[]; Mst={}; s=1;
for M=[50,200,1000,10000]; %set search region size;
    pfmax=2*(1-Pc)/(M-1); pfmin=pfmax/100; stp=(pfmax-pfmin)/100; %range of candidate false alarm probabilities and step of their change;
    pf=[pfmin:stp:pfmax]; y=(1-pf).^(M-1);  nmb=length(pf); %vector of false alarm probabilities;
    pd=(M*Pc*(pf.*(1-y)))./(1-y.*(1+pf*(M*Pc-1))); %vector of detection probabilities;
    thr=sqrt(2*log(1./pf)); %vector of thresholds securing the false alarm probabilities pf;
    for k=1:nmb
        td(k)=invmarc(pd(k),thr(k)); 
        td(k)=td(k)^2; %dwelling time found by inverting Marcum function (see(8.17));
    end; %vector of dwelling times for every value ;
    Ts=[Ts;(((1-Pc)./pf)+Pc./pd).*td/M]; %average acquisition time;
    Mst{s}=num2str(M);
    s=s+1;
end;
plot(pd,Ts'); xlim([0.75,0.999]); ylim([20,34]); xlabel('p_{d}'); ylabel('Ts/M'); legend(Mst); grid; %plotting dependences of acquisition time on pd for all given M;