移动通信中分集合并技术

等增益（egc）合并

所有接收到的支路信号加权系数均为1，实现方式较为简单，合并器的各个加权系数均为1，同样比较误码率为10^-2,M=2时信噪比为1.41，比选择式合并小，（理论上，没有分集时的信噪比为M=2时的1.78倍，较为吻合）

clear all
L_frame=100; N_packet=5000; 
SNRdBs=[0:20]; 
for iter=1:4 %选择几分集
if iter==1, NT=1; NR=1; gs='-kx'; % 11
elseif iter==2, NT=1; NR=2; gs='-^'; % 12 
elseif iter==3, NT=1; NR=4; gs='-ro'; % 14
else  iter==4,NT==1; NR=8; gs='-g*'; % 18
end 

for i_SNR=1:length(SNRdBs) 
SNRdB=SNRdBs(i_SNR); 
sigma=sqrt(0.5/(10^(SNRdB/10))); 
for i_packet=1:N_packet 
    symbol_data=randi([0 1],L_frame*2,NT); 
    [temp,sym_tab]=modulator(symbol_data.');
   X=temp.'; % frlg=length(X); 
Hr = (randn(L_frame,NR)+1i*randn(L_frame,NR))/sqrt(2); 
H = reshape(Hr,L_frame,NR);
 Habs = sum(abs(H).^2,2); 
Z=0; 
for i=1:NR 
 R(:,i) = sum(H(:,i).*X,2)+sigma*(randn(L_frame,1)+j*randn(L_frame,1));
 Z = Z + R(:,i).*(conj(H(:,i))./abs(H(:,i)));
end 
for m=1:4 
d1(:,m)=abs(sum(Z,2)-sym_tab(m)).^2+(-1+sum(Habs,2))*abs(sym_tab(m))^2; 
end
 [y1,i1] = min(d1,[],2); 
Xd=sym_tab(i1).';
 temp1 = X>0; temp2 = Xd>0; 
noeb_p(i_packet)=sum(sum(temp1~=temp2)); 
end 
BER(iter,i_SNR) = sum(noeb_p)/(N_packet*L_frame*2);
 end% end of FOR loop for SNR 
semilogy(SNRdBs,BER(iter,:),gs), hold on, axis([SNRdBs([1 end]) 1e-6 1e0])
 end 
title('BER perfoemancde of EGC Scheme'), xlabel('SNR[dB]'), ylabel('BER')
grid on, set(gca,'fontsize',9) 
legend('SISO','EGC (Tx:1,Rx:2)','EGC(Tx:1,Rx:4)','EGC(Tx:1,Rx:8)')