matlab实现协作中继放大转发

clear all; Monte_MAX=10^(5); %the length set of data frame M=[1,10,100,1000]; MIN_SNR=0; MAX_SNR=30; INTEVAL=2; POW_DIV=1/2; %/fid=fopen('record.txt','w'); %fprintf(fid,'%%%s\n',datestr(now)); %close(fid); %sr_distance=[0.1,0.5,0.7,0.9]; sd_distance=1; rd_distance=1; sr_distance=1; for M_INDEX=1:4 %the length of data frame M2=M(M_INDEX); count=0; for SNR=MIN_SNR:INTEVAL:MAX_SNR sig=10^(SNR/10); count=count+1; %just display something on the screen. datestr(now) M2 SNR err_num_dsd=0; err_num_coop=0; for tries=0:Monte_MAX %generate the source BPSK signal, 0,1 X1=rand(1,M2)>0.5; %generate the source BPSK signal,+1,-1 Xs=X1*2-1; %the transmitted signal Xst=sqrt(POW_DIV*sig)*Xs; %%%%？？？？？？ %generate the source-relay channel, the channel is varied each bit CH_sr=xy_RayleighCH(1)/(sr_distance)^2; %the received signal of coop source-relay transmission R_dsr=CH_sr*Xst+xy_noise(M2); %中继协作节点接收到的信号 %关键点之一：放大系数的选择 %the amplified signal of relay to destination amp_coff=sqrt(POW_DIV*sig/(1+POW_DIV*sig*CH_sr*conj(CH_sr))); Xr=R_dsr*amp_coff; %中继转发的信号 %the real ber, just for test %cBER=sum(Xs~=Xr)/M2; %if (sum(Xs~=Xr)>0) tx_coop=0; end tx_coop=1; %generate the source-destination channel CH_sd=xy_RayleighCH(1)/(sd_distance)^2; %the received signal of direct source-destination transmission R_dsd=CH_sd*sqrt(sig).*Xs+xy_noise(M2);%源节点直传到目的节点的信号， %%%%？？？？？？ %the decode signal of direct source-destination transmission Y_dsd=(conj(CH_sd)*sqrt(sig).*R_dsd>0)*2-1;%对直传接收信号译码 %the received signal of cooperative source-destination transmission R_csd=CH_sd*Xst+xy_noise(M2); %generate the relay-destination channel, the channel is varied each bit CH_rd=xy_RayleighCH(1)/(rd_distance)^2; %the received signal of cooperative relay-destination transmission R_crd=CH_rd*Xr+xy_noise(M2); %关键点之二：合并时候的噪声功率归一化处理 MRC最大比合并 R_combine=conj(CH_sd)*sqrt(POW_DIV*sig)*R_csd+amp_coff*sqrt(POW_DIV*sig)... *conj(CH_sr)*conj(CH_rd).*R_crd/(1+amp_coff^2*conj(CH_rd)*CH_rd); %the decode signal of cooperative MRC combining Y_combine=(R_combine>0)*2-1; %the number of packet error rate, if one bit is different, then the packet is discarded if sum(Xs~=Y_dsd)>0 err_num_dsd=err_num_dsd+1; end if sum(Xs~=Y_combine)>0 err_num_coop= err_num_coop+1; end end %try=0:Monte_MAX %the real ber ber_dsd(count)=err_num_dsd/(Monte_MAX); ber_coop(count)=err_num_coop/(Monte_MAX); % ber_dsd(count)=err_num_dsd; %ber_coop(count)=err_num_coop; end % SNR=MIN_SNR:MAX_SNR fid=fopen('record.txt','a'); fprintf(fid,'\n%%ber_dsd is\nber_dsd_ad%d=[ ',M_INDEX); fprintf(fid,'%d ',ber_dsd); fprintf(fid,'];\n'); fprintf(fid,'\n%%fixed ber_coop is\nber_coop_AF%d=[ ',M_INDEX); fprintf(fid,'%d ',ber_coop); fprintf(fid,'];\n'); fclose(fid); end %M index SNR1=MIN_SNR:INTEVAL:MAX_SNR; %瑞利信道下的直接发送的理论BER表达式 sig1=10.^(SNR1/10); u1=sqrt(sig1./(1+sig1)); Pe10=1/2*(1-u1); %瑞利信道下的二阶分集理论BER表达式，使用半功率 sig2=1/2*10.^(SNR1/10); u2=sqrt(sig2./(1+sig2)); Pe20=1/4*(1-u2).^(2).*(2+u2); %使用半对数画出SNR和BER的曲线 semilogy(SNR1,ber_dsd,'-o',SNR1,ber_coop,'-+',SNR1,Pe10,'-+',SNR1,Pe20,'-*'); legend('direct','cooperative','L=1, therotic','L=2 therotic'); grid on; ylabel('The AVERAGE BER'); xlabel('SNR(dB)'); title('the cooperative BER of BPSK in Rayleigh fading channel'); axis([MIN_SNR,MAX_SNR,10^(-6),1]);