Multiplet-Ruili-weak-channel.zip_多径_多径瑞丽衰落_多径衰落_瑞丽多径信道_衰落信道

clear all nSamp = 8; %矩形脉冲的取样点数 numSymb = 10000; %每种SNR下的传输的符号数 ts=1/(numSymb*nSamp); t=(0:numSymb*nSamp-1)*ts; M=4; %QPSK的符号类型数 SNR=-3:3; %SNR的范围 grayencod=[0 1 3 2]; %Gray编码格式 for ii=1:length(SNR) msg=randsrc(1,numSymb,[0:3]); %产生发送符号 msg_gr=grayencod(msg+1); %进行Gray编码影射 msg_tx=pskmod(msg_gr,M); %QPSK调制 msg_tx=rectpulse(msg_tx,nSamp); %矩形脉冲成形 h=rayleigh(10,t); %生成瑞利衰落 msg_tx1=h.*msg_tx; %信号通过瑞利衰落信道 msg_rx=awgn(msg_tx,SNR(ii)); %通过AWGN信道 msg_rx1=awgn(msg_tx1,SNR(ii)); msg_rx_down = intdump(msg_rx,nSamp); %匹配滤波相干解调 msg_rx_down1 = intdump(msg_rx1,nSamp); msg_gr_demod = pskdemod(msg_rx_down,M); %QPSK解调 msg_gr_demod1 = pskdemod(msg_rx_down1,M); [dummy graydecod] = sort(grayencod); graydecod = graydecod - 1; msg_demod = graydecod(msg_gr_demod+1); %Gray编码逆映射 msg_demod1 = graydecod(msg_gr_demod1+1); [errorBit BER(ii)] = biterr(msg, msg_demod, log2(M)); %计算AWGN信道BER [errorBit1 BER1(ii)] =biterr(msg,msg_demod1,log2(M)); %计算瑞利衰落+AWGN信道BER [errorSym SER(ii)] = symerr(msg, msg_demod); %计算AWGN信道SER [errorSym SER1(ii)] = symerr(msg, msg_demod1); %计算瑞利衰落+AWGN信道SER end figure semilogy(SNR,BER,'-ro',SNR,SER,'-r*',SNR,BER1,'-r.',SNR,SER1,'-r^') %画出BER和SER随SNR变化的曲线 legend('AWGN信道BER','AWGN信道SER','Rayleigh衰落+AWGN信道BER','Rayleigh衰落+AWGN信道SER') title('QPSK在AWGN和Rayleigh衰落信道下的性能') xlabel('信噪比（dB）') ylabel('误符号率和误比特率')