betHODM.zip_android开发

% Vinay Mohan Jonnakuti % Wireless Communication: % BPSK modulation and demodulation with increased bit rate %BPSK simulation using a carrier cosine wave with increased bit rate clc; close all; clear all; % no of sub carrier channels channels=6; c=6; % bits per channels bits=54 % total no of bits to be transmitted n=324; for i=1:n data(i)= 2*round(rand)-1; end % Converting the series into parallel for the channels s = reshape(data,c,bits); % BPSK modulation for a single channel signal1 = s(1,:); %first expand the bit stream exdata1=[]; exdata2=[]; exdata3=[]; exdata4=[]; exdata5=[]; exdata6=[]; for i=1:length(signal1) for rep=1:2 exdata1= [exdata1 signal1(i)]; end end signal2 = s(2,:); %first expand the bit stream exdata=[]; for i=1:length(signal2) for rep=1:2 exdata2= [exdata2 signal2(i)]; end end signal3= s(3,:); %first expand the bit stream exdata=[]; for i=1:length(signal3) for rep=1:2 exdata3= [exdata3 signal3(i)]; end end signal4= s(4,:); %first expand the bit stream exdata=[]; for i=1:length(signal4) for rep=1:2 exdata4= [exdata4 signal4(i)]; end end signal5= s(5,:); %first expand the bit stream exdata=[]; for i=1:length(signal5) for rep=1:2 exdata5= [exdata5 signal5(i)]; end end signal6= s(6,:); %first expand the bit stream exdata=[]; for i=1:length(signal6) for rep=1:2 exdata6= [exdata6 signal6(i)]; end end % Bpsk modulation m=10*n; % Generating the carrier signal ts=.1; tp=1:ts:11.79; carrier1=cos(2*pi*tp); % Generating the modulated signal 1 bpsk_sig1=exdata1.*carrier1; % Generating the modulated signal 2 carrier2=cos(4*pi*tp); bpsk_sig2=exdata2.*carrier2; % Generating the modulated signal 3 carrier3=cos(6*pi*tp); bpsk_sig3=exdata3.*carrier3; % Generating the modulated signal 4 carrier4=cos(8*pi*tp); bpsk_sig4=exdata4.*carrier4; % Generating the modulated signal 5 carrier5=cos(10*pi*tp); bpsk_sig5=exdata5.*carrier5; carrier6=cos(12*pi*tp); % Generating the modulated signal bpsk_sig6=exdata6.*carrier6; % taking the iFFT of each of these signals if_sig1=ifft(bpsk_sig1); if_sig2=ifft(bpsk_sig2); if_sig3=ifft(bpsk_sig3); if_sig4=ifft(bpsk_sig4); if_sig5=ifft(bpsk_sig5); if_sig6=ifft(bpsk_sig6); fin(1,:)=if_sig1; fin(2,:)=if_sig2; fin(3,:)=if_sig3; fin(4,:)=if_sig4; fin(5,:)=if_sig5; fin(6,:)=if_sig6; transmit=reshape(fin,1,648); % generating the noise % p=rand(1,800)*2*pi; p=rand*2*pi; snr=10; r=sqrt(-1*(1/snr*log(1 - rand))); % no = 5*(r.* exp(j*p)); no = (r.* exp(j*p)); % value of alpha al=rand+j*rand; %al=1; % Spreading channel with the alpha as the variable for k=2:2:646 for l = 1:2 %al=round(rand)+j*round(rand) rec(k+l)=transmit(k+l)+al*transmit(k-2+l); end end rxdata=rec+ no ; % Converting from serial to parallel myrec=reshape(rxdata,6,108) rxdata1=fft(myrec(1,:)); rxdata2=fft(myrec(2,:)); rxdata3=fft(myrec(3,:)); rxdata4=fft(myrec(4,:)); rxdata5=fft(myrec(5,:)); rxdata6=fft(myrec(6,:)); % taking the FFT %begin demodulation %first multiply recieved bitstream by cosine wave with carrier frequency uncarry1=rxdata1.*carrier1; uncarry2=rxdata2.*carrier2; uncarry3=rxdata3.*carrier3; uncarry4=rxdata4.*carrier4; uncarry5=rxdata5.*carrier5; uncarry6=rxdata6.*carrier6; %plot(uncarry) %demodulate by integrating dec1=[]; dec2=[]; dec3=[]; dec4=[]; dec5=[]; dec6=[]; for inc=1:2:length(uncarry1) dec=trapz(inc:inc+1,uncarry1(inc:inc+1)); dec1=[dec1 dec]; end %2 for inc=1:2:length(uncarry2) dec=trapz(inc:inc+1,uncarry2(inc:inc+1)); dec2=[dec2 dec]; end %3 for inc=1:2:length(uncarry3) dec=trapz(inc:inc+1,uncarry3(inc:inc+1)); dec3=[dec3 dec]; end %4 for inc=1:2:length(uncarry4) dec=trapz(inc:inc+1,uncarry4(inc:inc+1)); dec4=[dec4 dec]; end %5 for inc=1:2:length(uncarry5) dec=trapz(inc:inc+1,uncarry5(inc:inc+1)); dec5=[dec5 dec]; end %6 for inc=1:2:length(uncarry6) dec=trapz(inc:inc+1,uncarry6(inc:inc+1)); dec6=[dec6 dec]; end final_rec(1,:)=dec1; final_rec(2,:)=dec2; final_rec(3,:)=dec3; final_rec(4,:)=dec4; final_rec(5,:)=dec5; final_rec(6,:)=dec6; fin_rec_parallel=reshape(final_rec,1,324) %make decision with a threshold of zero demod=[]; for i=1:length(fin_rec_parallel) if fin_rec_parallel(i)>0 demod=[demod 1]; else demod=[demod -1]; end end %stem(demod) %calculate errors error=0; for i=1:length(demod) if data(i)~=demod(i) error=error+1; end end error; ber=error/324 figure(3) stem(data) hold stem(demod,'rx')