MATLAB实现MMSE预均衡.zip

% pre_MMSE.m %MIMO-OFDM Wireless Communications with MATLAB�� Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang %2010 John Wiley & Sons (Asia) Pte Ltd clear all; clf %%%%%% Parameter Setting %%%%%%%%% N_frame=100; N_packet=1000; b=2; M=2^b; % Number of bits per symbol and Modulation order mod_obj=modem.qammod('M',M,'SymbolOrder','Gray','InputType','bit'); demod_obj = modem.qamdemod(mod_obj); NT=4; NR=4; sq2=sqrt(2); I=eye(NR,NR); N_pbits = N_frame*NT*b; N_tbits = N_pbits*N_packet; fprintf('====================================================\n'); fprintf(' Pre-MMSE transmission'); fprintf('\n %d x %d MIMO\n %d QAM', NT,NR,M); fprintf('\n Simulation bits : %d',N_tbits); fprintf('\n====================================================\n'); SNRdBs = [0:2:20]; for i_SNR=1:length(SNRdBs) SNRdB = SNRdBs(i_SNR); noise_var = NT*0.5*10^(-SNRdB/10); sigma = sqrt(noise_var); rand('seed',1); randn('seed',1); N_ebits = 0; %%%%%%%%%%%%% Transmitter %%%%%%%%%%%%%%%%%% for i_packet=1:N_packet msg_bit = randint(N_pbits,1); % bit generation symbol = modulate(mod_obj,msg_bit).'; Scale = modnorm(symbol,'avpow',1); % normalization Symbol_nomalized = reshape(Scale*symbol,NT,N_frame); H = (randn(NR,NT)+j*randn(NR,NT))/sq2; temp_W = H'*inv(H*H'+noise_var*I); beta = sqrt(NT/trace(temp_W*temp_W')); % Eq.(12.17) W = beta*temp_W; Tx_signal = W*Symbol_nomalized; %%%%%%%%%%%%% Channel and Noise %%%%%%%%%%%%% Rx_signal = H*Tx_signal+sigma*(randn(NR,N_frame)+j*randn(NR,N_frame)); %%%%%%%%%%%%%% Receiver %%%%%%%%%%%%%%%%%%%%% y = Rx_signal/beta; % Eq.(12.18) Symbol_hat = reshape(y/Scale,NT*N_frame,1); msg_hat = demodulate(demod_obj,Symbol_hat); N_ebits = N_ebits + sum(msg_hat~=msg_bit); end BER(i_SNR) = N_ebits/N_tbits; end semilogy(SNRdBs,BER,'-k^','LineWidth',2); hold on; grid on; xlabel('SNR[dB]'), ylabel('BER'); legend('Pre-MMSE transmission')