?? ber_ofdm_64s_1e4_withclipping_snr20_differcr_1_2_3_nofilter.m
字號:
echo off;clear all;close all;clc;
fprintf( 'OFDM仿真\n') ;
tic
%無限幅
% --------------------------------------------- %
% 參數定義 %
% --------------------------------------------- %
% Initialize the parameters
NumLoop = 10000;
NumSubc = 64;
NumCP = 8;
SyncDelay = 0;
%-----------------------------------------------
%-----------------------------------------------
% Generate the random binary stream for transmit test
%-----------------------------------------------
BitsTx = floor(rand(1,NumLoop*NumSubc)*2);%用rand產生0：1的隨機數，不會產生負值，如果用randn會產生負值；乘以2是為了使用floor函數
% --------------------------------------------- %
% QAM MODULATION %
% --------------------------------------------- %
% Modulate (Generates QAM symbols)
% input: BitsTx(1,NumLoop*NumSubc); output:SymQAM(NumLoop,NumSubc/2)
SymQAMtmp = reshape(BitsTx,2,NumLoop*NumSubc/2).';
SymQAMtmptmp = bi2de(SymQAMtmp,2,'left-msb');%/?????(bi2de)
QAMTable = [-1-i -1+i 1-i 1+i];
SymQAM = QAMTable(SymQAMtmptmp+1);
% --------------------------------------------- %
% IFFT input: SymQAM(NumLoop,NumSubc/2); output: SymIFFT(NumSubc,NumLoop)
% --------------------------------------------- %
SymIFFT = zeros(NumSubc,NumLoop);
SymIFFTtmp = reshape(SymQAM,NumSubc/2,NumLoop)
SymIFFTtmptmp = zeros(NumSubc,NumLoop);
SymIFFTtmptmp(1,:) = real(SymIFFTtmp(1,:)); % 實數
SymIFFTtmptmp(NumSubc/2+1,:) = imag(SymIFFTtmp(1,:)); % 實數
SymIFFTtmptmp(2:NumSubc/2,:) = SymIFFTtmp(2:NumSubc/2,:);
SymIFFTtmptmp((NumSubc/2+2):NumSubc,:) = flipdim(conj(SymIFFTtmp(2:NumSubc/2,:)),1);
SymIFFT = ifft(SymIFFTtmp,NumSubc,1);%(后邊這個1是干什么的？)
% --------------------------------------------- %
% Add cyclic prefix %
% --------------------------------------------- %
% input: SymIFFT(NumSubc,NumLoop); output: SymCP(NumSubc + NumCP,NumLoop)
NumAddPrefix = NumSubc + NumCP;
SymCP = zeros(NumAddPrefix,NumLoop);
RowPrefix = (NumSubc - NumCP + 1):NumSubc;
SymCP = [SymIFFT(RowPrefix,:);SymIFFT];%(把保護間隔放在符號的前面)
% --------------------------------------------- %
% Go through the channel %
% --------------------------------------------- %
% input: SymCP(NumSubc + NumCP,NumLoop); output: SymCh(1,(NumSubc + NumCP)*NumLoop)
SymChtmp = zeros(1,(NumSubc + NumCP)*NumLoop);
SymChtmp = SymCP(:).'; % 進行這個轉置操作之后就成了一個矢量; 并串變換
% 相當于把矩陣的列向量依次排列 改變為一個行向量
%--------------------------------------------------
% Add the AWGN
%--------------------------------------------------
snrIndex = 0;
BerSnrTable_NOCP = zeros(7,2);
for snr=0:2:13; % = SNR + 10*log10(log2(2));
snrIndex = snrIndex+1;
BerSnrTable_NOCP(snrIndex,1) = snr;
SymCh = awgn(SymChtmp,snr,'measured');
% --------------------------------------------- %
% Remove Guard Intervals %
% --------------------------------------------- %
% input: SymCh(1,(NumSubc + NumCP)*NumLoop); output: SymDeCP(NumSubc,NumLoop)
SymDeCP = zeros(NumSubc,NumLoop);
SymDeCPtmp = reshape(SymCh,NumSubc + NumCP,NumLoop);
SymDeCP = SymDeCPtmp((NumCP+1+SyncDelay):NumAddPrefix+SyncDelay,:);
% --------------------------------------------- %
% FFT %
% --------------------------------------------- %
% input: SymDeCP(NumSubc,NumLoop); output: SymFFT(NumSubc,NumLoop)
SymFFT = fft(SymDeCP,NumSubc,1);
% --------------------------------------------- %
% Make Decision(Include DeQAM) %
% --------------------------------------------- %
% SymFFT(NumSubc,NumLoop); output: SymDec(NumSubc,NumLoop)
SymDec = zeros(NumSubc,NumLoop);
SymEqtmp(1,:) = SymFFT(1,:)+i*SymFFT(NumSubc/2+1,:);
SymEqtmp(2:NumSubc/2,:) = SymFFT(2:NumSubc/2,:);%???????????(SymEqtmp是哪里來的？)
for m = 1:NumLoop
for n = 1:NumSubc/2
Real = real(SymEqtmp(n,m));
Imag = imag(SymEqtmp(n,m));
if( abs((Real -1)) < abs((Real +1)))%????????每個點到坐標軸上1和-1的距離，哪個離1近就把1付給它，同理得-1
SymDec(2*n-1,m) = 1;
else
SymDec(2*n-1,m) = 0;%把實部放在奇數行
end
if( abs((Imag -1)) < abs((Imag +1 )) )
SymDec(2*n,m) = 1;
else
SymDec(2*n,m) = 0;%把虛部放在偶數行
end
end
end
%----------------------------------------------------------------------
% Bit Error
%----------------------------------------------------------------------
BitsRx = zeros(1,NumSubc*NumLoop);
BitsRx = SymDec(:).';
[Num,Ber] = symerr(BitsTx,BitsRx)%(BitsTx是原始數據符號)
%BerSnrTable(snr+1,2) = Num ;
BerSnrTable_NOCP(snrIndex,2) = Ber ;%BerSnrTable(snr+1,3) = Ber ;
end;
BerSnrTable_NOCP_plot=zeros(7,1);
BerSnrTable_NOCP_plot=BerSnrTable_NOCP(:,2);
save('NO_CR','BerSnrTable_NOCP_plot');
semilogy(BerSnrTable_NOCP(:,1),BerSnrTable_NOCP_plot,'o-');
legend('orignal');
xlabel('SNR');
ylabel('BER');
grid on;
hold on;
% -------------------------------------------------------CR-----------------
time_of_sim = toc
% end;
% %CR=1.2
% % --------------------------------------------- %
% % 參數定義 %
% % --------------------------------------------- %
% % Initialize the parameters
% % NumLoop = 10000;
% % NumSubc = 64;
% % NumCP = 8;
% % SyncDelay = 0;
% %-----------------------------------------------
%-----------------------------------------------
% Generate the random binary stream for transmit test
%-----------------------------------------------
BitsTx = floor(rand(1,NumLoop*NumSubc)*2);%用rand產生0：1的隨機數，不會產生負值，如果用randn會產生負值；乘以2是為了使用floor函數
% --------------------------------------------- %
% QAM MODULATION %
% --------------------------------------------- %
% Modulate (Generates QAM symbols)
% input: BitsTx(1,NumLoop*NumSubc); output:SymQAM(NumLoop,NumSubc/2)
SymQAMtmp = reshape(BitsTx,2,NumLoop*NumSubc/2).';
SymQAMtmptmp = bi2de(SymQAMtmp,2,'left-msb');%/?????(bi2de)
%--------------------------------------------------------------------------
QAMTable = [-1-i -1+i 1-i 1+i];
SymQAM = QAMTable(SymQAMtmptmp+1);
% --------------------------------------------- %
% IFFT input: SymQAM(NumLoop,NumSubc/2); output: SymIFFT(NumSubc,NumLoop)
% --------------------------------------------- %
SymIFFT = zeros(NumSubc,NumLoop);
SymIFFTtmp = reshape(SymQAM,NumSubc/2,NumLoop);%（為什么載波數除以2）
SymIFFTtmptmp = zeros(NumSubc,NumLoop);
SymIFFTtmptmp(1,:) = real(SymIFFTtmp(1,:)); % 實數
SymIFFTtmptmp(NumSubc/2+1,:) = imag(SymIFFTtmp(1,:)); % 實數
SymIFFTtmptmp(2:NumSubc/2,:) = SymIFFTtmp(2:NumSubc/2,:);
SymIFFTtmptmp((NumSubc/2+2):NumSubc,:) = flipdim(conj(SymIFFTtmp(2:NumSubc/2,:)),1);
SymIFFT = ifft(SymIFFTtmp,NumSubc,1);%(后邊這個1是干什么的？)
% --------------------------------------------- %
% Add cyclic prefix %
% --------------------------------------------- %
% input: SymIFFT(NumSubc,NumLoop); output: SymCP(NumSubc + NumCP,NumLoop)
NumAddPrefix = NumSubc + NumCP;
SymCP = zeros(NumAddPrefix,NumLoop);
RowPrefix = (NumSubc - NumCP + 1):NumSubc;
SymCP = [SymIFFT(RowPrefix,:);SymIFFT];%(把保護間隔放在符號的前面)
% --------------------------------------------- %
% 限幅 %
% --------------------------------------------- %
CR = 1.2;
SymCP_Clip_last = zeros(NumAddPrefix,NumLoop);
SymCP_Clip_temp3 = zeros(NumAddPrefix,1);
%SymCP_Clip_temp2 = zeros()
for nSymbol = 1:NumLoop
Signal_Power = abs(SymCP(:,nSymbol).^2);
Peak_Power = max(Signal_Power); %Peak_Power = max(Signal_Power,[],2);
Mean_Power = mean(Signal_Power);%Mean_Power = mean(Signal_Power,2);
A = CR*sqrt(Mean_Power);
SymCP_Clip_temp1 = SymCP(:,nSymbol)';%把第nSymbol列的值轉換成行向量并付給一個向量
SymCP_Clip_temp2 = SymCP_Clip_temp1(Signal_Power>A);
SymCP_Clip = A*SymCP_Clip_temp2./abs(SymCP_Clip_temp2);
SymCP_Clip_temp1(Signal_Power>A) = SymCP_Clip;
SymCP_Clip_temp3 = SymCP_Clip_temp1'
SymCP_Clip_last(:,nSymbol) = SymCP_Clip_temp3;
end
% --------------------------------------------- %
% Go through the channel %
% --------------------------------------------- %
% input: SymCP(NumSubc + NumCP,NumLoop); output: SymCh(1,(NumSubc + NumCP)*NumLoop)
SymChtmp = zeros(1,(NumSubc + NumCP)*NumLoop);
SymChtmp = SymCP_Clip_last(:).'; % 進行這個轉置操作之后就成了一個矢量; 并串變換
% 相當于把矩陣的列向量依次排列 改變為一個行向量
% % --------------------------------------------- %
% %濾波
% % --------------------------------------------- %
% Ch = [1 1/2 1/4];
% SymChtmptmp = filter(Ch,1,SymChtmp);%濾波
snrIndex4 = 0;
BerSnrTable_CR1P2 = zeros(7,2);%?????
for snr=0:2:13; % = SNR + 10*log10(log2(2));
snrIndex4=snrIndex4+1;
BerSnrTable_CR1P2(snrIndex4,1) = snr;
SymCh = awgn(SymChtmp,snr,'measured');
% --------------------------------------------- %
% Remove Guard Intervals %
% --------------------------------------------- %
% input: SymCh(1,(NumSubc + NumCP)*NumLoop); output: SymDeCP(NumSubc,NumLoop)
SymDeCP = zeros(NumSubc,NumLoop);
SymDeCPtmp = reshape(SymCh,NumSubc + NumCP,NumLoop);
SymDeCP = SymDeCPtmp((NumCP+1+SyncDelay):NumAddPrefix+SyncDelay,:);
% --------------------------------------------- %
% FFT %
% --------------------------------------------- %
% input: SymDeCP(NumSubc,NumLoop); output: SymFFT(NumSubc,NumLoop)
SymFFT = fft(SymDeCP,NumSubc,1);
% --------------------------------------------- %
% Make Decision(Include DeQAM) %
% --------------------------------------------- %
% SymFFT(NumSubc,NumLoop); output: SymDec(NumSubc,NumLoop)
SymDec = zeros(NumSubc,NumLoop);
SymEqtmp(1,:) = SymFFT(1,:)+i*SymFFT(NumSubc/2+1,:);
SymEqtmp(2:NumSubc/2,:) = SymFFT(2:NumSubc/2,:);%???????????(SymEqtmp是哪里來的？)
for m = 1:NumLoop
for n = 1:NumSubc/2
Real = real(SymEqtmp(n,m));
Imag = imag(SymEqtmp(n,m));
if( abs((Real -1)) < abs((Real +1)))%????????每個點到坐標軸上1和-1的距離，哪個離1近就把1付給它，同理得-1
SymDec(2*n-1,m) = 1;
else
SymDec(2*n-1,m) = 0;%把實部放在奇數行
end
if( abs((Imag -1)) < abs((Imag +1 )) )
SymDec(2*n,m) = 1;
else
SymDec(2*n,m) = 0;%把虛部放在偶數行
end
end
end
%----------------------------------------------------------------------
% Bit Error
%----------------------------------------------------------------------
BitsRx = zeros(1,NumSubc*NumLoop);
BitsRx = SymDec(:).';
[Num,Ber] = symerr(BitsTx,BitsRx)%(BitsTx是原始數據符號)
%BerSnrTable(snr+1,2) = Num ;
BerSnrTable_CR1P2 (snrIndex4,2) = Ber ;%BerSnrTable(snr+1,3) = Ber ;
end;
BerSnrTable_CR1P2_plot = zeros(7,1);
BerSnrTable_CR1P2_plot=BerSnrTable_CR1P2(:,2);
save('CR_1P2','BerSnrTable_CR1P2_plot');
semilogy(BerSnrTable_CR1P2(:,1),BerSnrTable_CR1P2_plot,'+-r');
legend('CR=3');
% xlabel('SNR');
% ylabel('BER');
grid on;
hold on;
% ------------------------------------------------------------------------
time_of_sim = toc
%CR=0.8
% --------------------------------------------- %
% 參數定義 %
% --------------------------------------------- %
% Initialize the parameters
% NumLoop = 10000;
% NumSubc = 64;
% NumCP = 8;
% SyncDelay = 0;
%-----------------------------------------------
%-----------------------------------------------
% Generate the random binary stream for transmit test
%-----------------------------------------------
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