pr8_14.m

Spread Spectrum and CDMA Principles and Applications 书籍和代码

%Problem 8.14;
%Rapid acquisition sequences efficiency;

clear all; close all;
n=[2:17]; %number of RAS components;
Pc=0.999; %probability of correct acquisition;
L=2.^n; %length;
Pc0=Pc.^(1./n); %probability of correct decision per step;
q=norminv(Pc0,0,1); %accumulated SNR per step found by inverting ;
T=(n.^2).*(q.^2); %entire energy SNR for search;
pf=1.8*(1-Pc)./(1.1*(L-1)); %false alarm probability for serial search under miss probability taken to be 0.9;
Tss=((1-Pc)./pf+Pc/0.9).*((norminv(1-pf,0,1)+norminv(0.9,0,1)).^2); %acquisition time for serial search for a baseband signal;
G=Tss./T; %time gain of RAS;
subplot(121); semilogy(n,Tss,n,T); grid; xlabel('logL'); ylabel('T_{acq}'); legend('serial','rapid acq.'); %plotting acquisition times for serial search and rapid acquisition sequence;
subplot(122); plot(n,G); grid; xlabel('logL'); ylabel('Acq. time gain'); %plotting gain of rapid acquisition sequences;