基于卷积编码维特比译码+BPSK+MRC通信链路matlab误码率仿真【包含程序操作录像，中文注释】

%解码与F、检测与F、放大与转发的比较 %带WGN的平坦衰落中的BPSK： %绘制了误码率的仿真结果和理论结果。 %使用MRC组合两个信号 %使用平均BER clc clear all close all sum_dcf = 0; sum_dtf = 0; sum_af = 0; N_bits = 15000; %数据位数 %对结果进行平均的迭代次数 N_iter = 15; for iter = 1:N_iter %随机数据位 data = round(rand(N_bits,1)); %使用速率1/2卷积码的信道编码： trellis = poly2trellis(3,[5 7]); %格子结构 c_data = convenc(data,trellis); %BPSK调制 tx = 2*c_data - 1; %频道特性 SNRdB = -3:20; %研究BER的SNR范围 %附加噪声和中继信道的信道响应： %源上行信道： noise_d = 1/sqrt(2) * (randn(2 * N_bits,1) + j * randn(2 * N_bits,1)); h_d = 1/sqrt(2) * (randn(2 * N_bits,1) + j * randn(2 * N_bits,1)); %用户间通道： noise_r1 = 1/sqrt(2) * (randn(2 * N_bits,1) + j * randn(2 * N_bits,1)); h_r1 = 1/sqrt(2) * (randn(2 * N_bits,1) + j * randn(2 * N_bits,1)); %对于中继上行链路： noise_r2 = 1/sqrt(2) * (randn(2 * N_bits,1) + j * randn(2 * N_bits,1)); h_r2 = 1/sqrt(2) * (randn(2 * N_bits,1) + j * randn(2 * N_bits,1)); for k = 1:length(SNRdB) SNR = 10^(SNRdB(k)/10); %将SNRdB转换为线性值SNR ftx_r1 = sqrt(SNR) * h_r1 .* tx + noise_r1; %均衡 eq_rx1 = ftx_r1 .* conj(h_r1); %硬判决与双极转换 r_bits = (sign(real(eq_rx1)) + 1)/2; %通道解码： dec_dcf_r1 = vitdec(r_bits,trellis,3,'term','hard'); %使用与Source相同的过程重新编码： c_data2 = convenc(dec_dcf_r1,trellis); %用于继电器编码数据的BPSK信号： tx2_dcf = 2 * c_data2 - 1; %检测 dec_dtf_r1 = sign(real(eq_rx1)); tx2_dtf = dec_dtf_r1; %放大： beta = sqrt(1./((SNR * abs(h_r1).^2) + 1)); %amplification: ftx_amp = ftx_r1 .* beta; %中继到目标% %DCF ftx_dcf_r2 = sqrt(SNR) * tx2_dcf .* h_r2 + noise_r2 ; %DTF ftx_dtf_r2 = sqrt(SNR) * tx2_dtf .* h_r2 + noise_r2 ; %AF ftx_af_r2 = sqrt(SNR) * ftx_amp .* h_r2 + noise_r2 ; %%%%%%%%%%%%%%%%% At the Destination%%%%%%%%%%% ftx_d = sqrt(SNR)* tx .* h_d + noise_d; %%%%%%%%%%%%%%%%%%%%%%%%DCF%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%MRC%%%%%%%%%%%%%%% R_dcf = ftx_dcf_r2 .* conj(h_r2) + ftx_d .* conj(h_d); %hard dec_com_dcf = sign(real(R_dcf)); %误码率计算 %at destination: err_com1(k) = sum(abs(dec_com_dcf - tx)/2); simber_com1(k) = err_com1(k) / (2 * N_bits); R_dtf = ftx_dtf_r2 .* conj(h_r2) + ftx_d .* conj(h_d); %hard decision dec_com_dtf = sign(real(R_dtf)); %误码率计算 %at destination: err_com2(k) = sum(abs(dec_com_dtf - tx)/2); simber_com2(k) = err_com2(k) / (2 * N_bits); R_af = ftx_af_r2 .* conj(h_r2) .* conj(h_r1) + ftx_d .* conj(h_d); dec_com_af = sign(real(R_af)); %误码率计算 err_com3(k) = sum(abs(dec_com_af - tx)/2); simber_com3(k) = err_com3(k) / (2 * N_bits); theberawgn(k) = 0.5 * erfc (sqrt(SNR));%AWGN的理论误码率 theberrayleigh(k) = 0.5 * (1 - sqrt(SNR./(1 + SNR))); %理论瑞利 mue = sqrt(SNR/(1+SNR)); mrcth(k) = 0.25 * (2 + mue) * (1-mue)^2;%理论2Rx MRC end sum_dcf = sum_dcf + simber_com1; sum_dtf = sum_dtf + simber_com2; sum_af = sum_af + simber_com3; end %average BER: avgber_dcf = sum_dcf/N_iter; avgber_dtf = sum_dtf/N_iter; avgber_af = sum_af/N_iter; %误码率图 figure semilogy(SNRdB,avgber_dcf,SNRdB,avgber_dtf,SNRdB,avgber_af,SNRdB,theberawgn,SNRdB,theberrayleigh,SNRdB,mrcth); axis([SNRdB(1) max(SNRdB) 10^-5 0.5]); grid on legend('DCF','DTF','AF','AWGN','Rayleigh','MRC 2 senders'); xlabel('SNR dB'); ylabel('BER');