基于matlab的2x2VBLAST-MIMO-OFDM通信系统误码率仿真+代码仿真操作视频

clc; clear; close all; warning off; addpath(genpath(pwd)); num_frames = 10^2; % simulation runs FFT_len = 1024; % length of the FFT/IFFT chan_len = 10; % number of channel taps cp_len = chan_len-1; % length of the cyclic prefix fade_var_1D = 0.5; % 1D fade variance SNR_dBs = [0:5:40]; for ij = 1:length(SNR_dBs) ij SNR_dB = SNR_dBs(ij); % SNR per bit (dB) noise_var_1D = 2*fade_var_1D*chan_len*2*2*2/(2*10^(0.1*SNR_dB)*FFT_len*2*2); C_Ber = 0; % bit errors in each frame tic() for frame_cnt = 1:num_frames %---------------------------TRANSMITTER------------------------------------ % QPSK symbols from transmit antenna 1 a1 = randi([0 1],1,2*FFT_len); qpsk_seq1 = 1-2*a1(1:2:end) + 1i*(1-2*a1(2:2:end)); % QPSK symbols from transmit antenna 2 a2 = randi([0 1],1,2*FFT_len); qpsk_seq2 = 1-2*a2(1:2:end) + 1i*(1-2*a2(2:2:end)); % IFFT operation at transmitter 1 T_sig1 = ifft(qpsk_seq1); % IFFT operation at transmitter 2 T_sig2 = ifft(qpsk_seq2); % Insert cyclic prefix at transmitter 1 T_sig_CP1 = [T_sig1(end-cp_len+1:end) T_sig1]; % Insert cyclic prefix at transmitter 2 T_sig_CP2 = [T_sig2(end-cp_len+1:end) T_sig2]; % -------------------- CHANNEL -------------------------------------------- % fade channel for transmitter 1 and receiver 1 fade_chan11 = normrnd(0,sqrt(fade_var_1D),1,chan_len)+1i*... normrnd(0,sqrt(fade_var_1D),1,chan_len); fade_chan_FFT11 = fft(fade_chan11,FFT_len); % fade channel for transmitter 2 and receiver 1 fade_chan21 = normrnd(0,sqrt(fade_var_1D),1,chan_len)+1i*... normrnd(0,sqrt(fade_var_1D),1,chan_len); fade_chan_FFT21 = fft(fade_chan21,FFT_len); % fade channel for transmitter 1 and receiver 2 fade_chan12 = normrnd(0,sqrt(fade_var_1D),1,chan_len)+1i*... normrnd(0,sqrt(fade_var_1D),1,chan_len); fade_chan_FFT12 = fft(fade_chan12,FFT_len); % fade channel for transmitter 2 and receiver 2 fade_chan22 = normrnd(0,sqrt(fade_var_1D),1,chan_len)+1i*... normrnd(0,sqrt(fade_var_1D),1,chan_len); fade_chan_FFT22 = fft(fade_chan22,FFT_len); % AWGN at receiver 1 noise1 = normrnd(0,sqrt(noise_var_1D),1,FFT_len+cp_len+chan_len-1)+1i*... normrnd(0,sqrt(noise_var_1D),1,FFT_len+cp_len+chan_len-1); % AWGN at receiver 2 noise2 = normrnd(0,sqrt(noise_var_1D),1,FFT_len+cp_len+chan_len-1)+1i*... normrnd(0,sqrt(noise_var_1D),1,FFT_len+cp_len+chan_len-1); % Get channel output for first receiver (diversity arm) chan_op1 = conv(fade_chan11,T_sig_CP1)+conv(fade_chan21,T_sig_CP2)+noise1; % Get channel output for second receiver (diversity arm) chan_op2 = conv(fade_chan12,T_sig_CP1)+conv(fade_chan22,T_sig_CP2)+noise2; %------------- VBLAST RECEIVER -------------------------------------------- start_inx = cp_len+1; % starting index end_inx = start_inx + FFT_len-1; % end index % FFT output at diversity arm 1 Rx_FFT_op1 = fft(chan_op1(start_inx:end_inx)); % FFT output at diversity arm 2 Rx_FFT_op2 = fft(chan_op2(start_inx:end_inx)); dec_a1 = zeros(1,2*FFT_len); dec_a2 = zeros(1,2*FFT_len); for i1 = 1:FFT_len H_matrix = [fade_chan_FFT11(i1) fade_chan_FFT21(i1);... fade_chan_FFT12(i1) fade_chan_FFT22(i1)]; pseudo_inv_H = pinv(H_matrix); % step 1 y1 = pseudo_inv_H(1,:)*[Rx_FFT_op1(i1);Rx_FFT_op2(i1)] ; % ML decision dec_a1(i1*2-1)= real(y1)<0; dec_a1(i1*2)= imag(y1)<0; % step 2 y2 = [Rx_FFT_op1(i1);Rx_FFT_op2(i1)] - H_matrix(:,1)*(1-2*dec_a1(i1*2-1)+... 1i*(1-2*dec_a1(i1*2))); % performing Maximum Ration Combining h=H_matrix(:,2); h=h/norm(h); % beamformer y2 = h'*y2; % ML decision dec_a2(i1*2-1)= real(y2)<0; dec_a2(i1*2)= imag(y2)<0; end C_Ber = C_Ber+ nnz(a1-dec_a1+a2-dec_a2); end toc() BER(ij) = C_Ber/(num_frames*(4*FFT_len)); end figure; semilogy(SNR_dBs,BER,'r-o'); grid on xlabel('SNR'); ylabel('error');