基于matlab的MIMO-OFDM系统Alamouti预编码对误码率的性能影响分析+代码仿真操作视频

clc; clear; close all; warning off; addpath(genpath(pwd)); L_frame = 400; % 帧长度和帧个数 N_iter = 1000; Nmod = 2; M = 2^Nmod; SNRs_dB = 0:2:20; %信噪比 SNRs = 10.^(SNRs_dB / 10.); N_SNR = length(SNRs_dB); T = 2; % Alamouti长度T N_M = 2; % 列向量长度，码字长度 L_code = 64;% 码本长度 NT = 4; % 发射和接收天线个数 NR = 1; N_frame_bit = NT*Nmod*L_frame; %一帧比特数 N_totoal_bit = N_frame_bit*N_iter;% 总比特数 code_book = CodebookGenerator(NT, N_M, L_code);%生成码本 y = zeros(2,1,L_frame); Rx = zeros(1,2,L_frame); BERs = zeros(2, N_SNR); for isnr = 1:N_SNR SNR = SNRs(isnr); sigma = sqrt(NT/(2*SNR)); n_biterror = 0; for iiter = 1:N_iter [isnr,iiter] frame_origin = randi([0,1], L_frame, Nmod*N_M); % 生成随机数 % 调制 frame_mod = QPSKMod(frame_origin,L_frame,N_M); % Alamouti发送 frame_transmit = reshape(frame_mod, N_M, 1, L_frame); frame_alamouti = [frame_transmit(1,1, :) -conj(frame_transmit(2,1, :)); frame_transmit(2,1, :) conj(frame_transmit(1,1, :))]; % 信道和噪声 Hiid = (randn(NR,NT)+1j*randn(NR,NT))/sqrt(2); arg_W = zeros(1, L_code); for ih = 1:L_code arg_W(ih) = norm(Hiid*code_book(:,:,ih),'fro'); end [arg_val, arg_Index] = max(arg_W); HW = Hiid*code_book(:,:,arg_Index); for iframe = 1:L_frame Rx(:,:,iframe) = HW*frame_alamouti(:,:,iframe)+sigma*(randn(NR,T)+1j*randn(NR,T)); end % 接收 HW_re = [conj(HW(1)) HW(2); conj(HW(2)) -HW(1)]; Rx_re = [Rx(1,1,:); conj(Rx(1,2,:))]; for iframe = 1:L_frame y(:,:,iframe) = HW_re* Rx_re(:,:,iframe)./norm(HW)^2; end frame_re = reshape(y, L_frame, N_M); frame_demod = QPSKDemod(frame_re,L_frame,N_M); % 计算误码率 n_biterror_tmp = sum(sum(abs(frame_demod - frame_origin))); n_biterror = n_biterror + n_biterror_tmp; end BERs(1, isnr) = n_biterror/(N_iter*L_frame*Nmod*N_M); end figure; BERs2 = [0.345555000000000 0.245437500000000 0.151757500000000 0.0813550000000000 0.0365075000000000 0.0133750000000000 0.00412000000000000 0.00103500000000000 0.000242500000000000 5.00000000000000e-05 2.25000000000000e-05]; semilogy(SNRs_dB,BERs(1,:),"-^", SNRs_dB,BERs2,'-+'); axis([SNRs_dB([1 end]) 1e-6 1e0]); xlabel('SNR[dB]'), ylabel('BER'); legend('Alamouti预编码','无Alamouti预编码');