基于matlab的MIMO-OFDM通信系统mse性能曲线仿真,对比64个子载波和256个子载波的性能+代码仿真操作视频

function [ofdm chan] = MIMO_OFDM(ofdmIn,chanIn,M) ofdm.Nb = 1e3; ofdm.Nt = 2; ofdm.Nr = 2; ofdm.K = M; ofdm.G = 1/4; ofdm.Mod = 16; ofdm.PSpace = 1; chan.L = 6; ofdm.ifDemodulateData = 1; ofdm.ifDisplayResults = 1; if nargin > 3 error('Only two arguments can be set as inputs') elseif nargin == 3 % updating the set parameters S = fieldnames(ofdmIn); for nS = 1:length(S) ofdm.(S{nS}) = ofdmIn.(S{nS}); end S = fieldnames(chanIn); for nS = 1:length(S) chan.(S{nS}) = chanIn.(S{nS}); end elseif nargin == 1 S = fieldnames(ofdmIn); for nS = 1:length(S) ofdm.(S{nS}) = ofdmIn.(S{nS}); end end ofdm.PPos = 1:(ofdm.PSpace+1):ofdm.K; % OFDM pilot positionss ofdm.PL = length(ofdm.PPos); % Length of pilot subcarriers ofdm.DPos = setxor(1:ofdm.K,ofdm.PPos); % OFDM data positions ofdm.DL = length(ofdm.DPos); % Length of data subcarriers ofdm.BER = 0; % set the BER to zero chan.sigma = sqrt(10^(-0.1*chan.SNR_dB)); % noise power temp = 0:ofdm.Mod-1; % possible symbols temp = qammod(temp,ofdm.Mod); % modulated symbols temp = abs(temp).^2; % power of each point in the constellation temp = mean(temp); % average energy of the constellation ofdm.ModNorm = 1/sqrt(temp); % normaliztion factor %% Data generation ofdm.d = randi(ofdm.Mod,ofdm.DL,ofdm.Nb,ofdm.Nt)-1; %% data Modulation ofdm.dMod = zeros(ofdm.K,ofdm.Nb,ofdm.Nt); if ofdm.DL > 0 for nt = 1 : ofdm.Nt ofdm.dMod(ofdm.DPos,:,nt) = ofdm.ModNorm*qammod(ofdm.d(:,:,nt),ofdm.Mod); end end %% Pilot insertion for nt = 1 : ofdm.Nt ofdm.dMod(ofdm.PPos,:,nt) = repmat(exp(-sqrt(-1)*2*pi*(nt-1)*chan.L*(1:ofdm.PL).'/ofdm.PL),1,ofdm.Nb); end ofdm.pow = var(ofdm.dMod(:))+abs(mean(ofdm.dMod(:)))^2; %% IFFT operation ofdm.ifft = zeros(ofdm.K,ofdm.Nb,ofdm.Nt); for nt = 1 : ofdm.Nt ofdm.ifft(:,:,nt) = sqrt(ofdm.K)*ifft(ofdm.dMod(:,:,nt),ofdm.K); end %% Cyclic perfix ofdm.ifftG = [ofdm.ifft(ofdm.K*(1-ofdm.G)+1:ofdm.K,:,:);ofdm.ifft]; %% Channel chan.Coeff = 1/sqrt(2)*1/sqrt(chan.L)*(randn(ofdm.Nt,ofdm.Nr,chan.L,ofdm.Nb)+sqrt(-1)*randn(ofdm.Nt,ofdm.Nr,chan.L,ofdm.Nb)); if ofdm.K*ofdm.G < chan.L+1 error('Guard interval is shorter than channel length, and the system does not function properly') end ofdm.Y = zeros(ofdm.K*(1+ofdm.G),ofdm.Nb,ofdm.Nr); for nb = 1 : ofdm.Nb for nt=1:ofdm.Nt for nr=1:ofdm.Nr ofdm.Y(:,nb,nr) = ofdm.Y(:,nb,nr) + filter(squeeze(chan.Coeff(nt,nr,:,nb)),1,ofdm.ifftG(:,nb,nt)); end end end ofdm.Y = ofdm.Y + chan.sigma*1/sqrt(2)*( randn(ofdm.K*(1+ofdm.G),ofdm.Nb,ofdm.Nr)+ sqrt(-1)*randn(ofdm.K*(1+ofdm.G),ofdm.Nb,ofdm.Nr) ); ofdm.fftG = ofdm.Y(ofdm.K*ofdm.G+1:ofdm.K*(1+ofdm.G),:,:); ofdm.fft = zeros(ofdm.K,ofdm.Nb,ofdm.Nr); for nr = 1 : ofdm.Nr ofdm.fft(:,:,nr) = 1/sqrt(ofdm.K)*fft(ofdm.fftG(:,:,nr),ofdm.K); end F = dftmtx(ofdm.K); F = F(:,1:chan.L); chan.CoeffEst = zeros(ofdm.Nt,ofdm.Nr,chan.L,ofdm.Nb); for nb = 1 : ofdm.Nb for nr = 1 : ofdm.Nr chan.A = zeros(ofdm.PL,chan.L*ofdm.Nt); for nt = 1 : ofdm.Nt chan.A(:,(1:chan.L)+(nt-1)*chan.L) = diag(ofdm.dMod(ofdm.PPos,nb,nt))*F(ofdm.PPos,:); end ChanEst = pinv(chan.A)*ofdm.fft(ofdm.PPos,nb,nr); for nt = 1 : ofdm.Nt chan.CoeffEst(nt,nr,:,nb) = ChanEst((1:chan.L)+(nt-1)*chan.L); end end end chan.MSE_Simulation = var(chan.Coeff(:)-chan.CoeffEst(:)); chan.MSE_Theory = chan.sigma^2/ofdm.PL; if ofdm.ifDisplayResults disp(['MSE of channel estimation (theory) is : ',num2str(chan.MSE_Theory)]) disp(['MSE of channel estimation (simulation) is : ',num2str(chan.MSE_Simulation)]) end if ofdm.ifDemodulateData == 1 && ofdm.DL > 0 % Building channel coefficients in frequency domain chan.CoeffEstFreq = zeros(ofdm.K,ofdm.Nt,ofdm.Nr,ofdm.Nb); for nb = 1 : ofdm.Nb for nr = 1 : ofdm.Nr for nt = 1 : ofdm.Nt chan.CoeffEstFreq(:,nt,nr,nb) = F*squeeze(chan.CoeffEst(nt,nr,:,nb)); end end end ofdm.H = chan.CoeffEstFreq(:,:,:,:); ofdm.dDemod = zeros(ofdm.DL,ofdm.Nb,ofdm.Nt); for nb = 1 : ofdm.Nb for dl = 1 : ofdm.DL ofdm.dDemod(dl,nb,:) = pinv(reshape(chan.CoeffEstFreq(ofdm.DPos(dl),:,:,nb),ofdm.Nt,ofdm.Nr)).' ... % ZF DETECTOR *squeeze(ofdm.fft(ofdm.DPos(dl),nb,:)); end end % detection ofdm.dEst = zeros(ofdm.DL,ofdm.Nb,ofdm.Nt); for nt = 1 : ofdm.Nt ofdm.dEst(:,:,nt) = qamdemod(1/ofdm.ModNorm * ofdm.dDemod(:,:,nt),ofdm.Mod); end % BER calculation [~,ofdm.BER] = biterr(ofdm.d(:),ofdm.dEst(:),log2(ofdm.Mod)); if ofdm.ifDisplayResults disp(['BER is = ',num2str(ofdm.BER)]) end end