petest_dist.m

H. Yang, A.P. Petropulu, X. Yang and T. Camp, ?ALLIANCES with Optimal Relay Selection,"IEEE Trans. o

%compute the Pe recursively based on pecompute for all possbile Xhat!=X
function [pe2]=petest_dist(snr_db,K,L,Dist0,Dist1,Dist2,m_coef)
%pe2=0; return; % this line for test use only
snr=10^(snr_db/10);
pe2=0;

%X=ones(1,K);
X=rand(1,K)>0.5;
X=X-not(X);
%begin iteration of Xhat
zz=zeros(1,K);
pe2=0;%inital value
for ii=1:2^K-1 %total possible Xhat for BPSKed X
    for jj=1:K
        if mod(ii,2^(jj-1))==0
            zz(jj)=not(zz(jj));
        end
    end
    % till now zz is a vecotor, with 1s and 0s. 1 means that bit is error.
    %sum(zz) is the number of error bits
    Xhat=X;%initial
    for ii=1:K
        if zz(ii)==1
            Xhat(ii)=-X(ii);% this bit is error
        end
    end
    %src_rly=zeros(1,K);% when this is used, it mean NO contribution of source relays
    src_rly=src_gen(K,L);% source relays. Taking into account the contribution of source relay
    pe2=pe2+sum(zz)/K*pecompute_dist(K,L,X,Xhat,snr,src_rly,Dist0,Dist1,Dist2,m_coef);
    %zz
    
    
end