2022年GMSK系统的建模与仿真MATLAB程序 .pdf

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1、主程序：sr=256000.0; % 符号率ml=1; % 解调电平数br=sr.*ml; % 比特率nd = 100; % 每次循环中的符号个数ebn0=15; % 信噪比IPOINT=8; % 过采样点数%* 滤波器初始化 * irfn=21; % 阶数B=0.25*sr; B2=0.6*sr; xh = gaussf(B,irfn,IPOINT,sr,1); %发送器滤波器设计xh2 =gaussf(B2,irfn,IPOINT,sr,0); %接收器滤波器设计%*衰落初始化 * tstp=1/sr/IPOINT; %时间分辨率itau = 0; %直达波形dlvl = 0; n0=6;

2、 %瑞利衰落th1=0.0; itnd0=nd*IPOINT*100; itnd1=1000; now1=1; fd=320; flat =1; %*开始计算 * nloop=1000; % 循环数noe = 0; % 错误数nod = 0; % 传送数据数目for iii=1:nloop %*产生数据 * data1=rand(1,nd.*ml)0.5; % rand: built in function subplot(4,2,1) ,stairs(data1); title(产生的原始信号 ) axis(0,50,-2,2); %*GMSK调制* data11=2*data1-1; da

3、ta2=oversamp(data11,length(data11),IPOINT); data3=conv(data2,xh); subplot(4,2,2),plot(data3); title(基带信号通过高斯白噪声后) th=zeros(1,length(data3)+1); ich2=zeros(1,length(data3)+1); qch2=zeros(1,length(data3)+1); for ii=2:length(data3)+1 名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - -

4、- - - - 第 1 页，共 5 页 - - - - - - - - - th(1,ii)=th(1,ii-1)+pi/2*data3(1,ii-1)./IPOINT; end ich2=cos(th); qch2=sin(th); fich2=fft(ich2,800); fqch2=fft(qch2,800); subplot(4,2,3),plot(abs(fich2); title(同相支路频谱 ); subplot(4,2,4),plot(abs(fqch2); title(正交支路频谱 ); %*衰减计算 * spow=sum(ich2.*ich2+qch2.*qch2)/nd;

5、 attn=0.5*spow*sr/br*10.(-ebn0/10); attn=sqrt(attn); %* 衰落信道 * ifade,qfade=sefade(ich2,qch2,itau,dlvl,th1,n0,itnd1,now1,length(ich2),tstp,fd,flat); %产生的数据送入衰落模拟器itnd1 = itnd1+ itnd0; %更新衰落计数器%*加性高斯白噪声 * ich3,qch3= comb(ifade,qfade,attn);% 加入高斯白噪声ich4,qch4 = compconv(ich3,qch3,xh2); syncpoint =irfn*I

6、POINT-IPOINT/2+1; ich5=ich4(syncpoint:IPOINT:length(ich4); qch5=qch4(syncpoint:IPOINT:length(qch4); fich5=fft(ich5,100); fqch5=fft(qch5,100); subplot(4,2,5),plot(abs(fich5); title(加入噪声后的同相支路频谱); subplot(4,2,6),plot(abs(fqch5); title(加入噪声后的正交支路频谱); %*GMSK解调* demoddata2(1,1)=-1; for k=3:2:nd*ml+1 demo

7、ddata2(1,k)=ich5(1,k)*qch5(1,k-1)*cos(pi*(k)0; end for n=2:2:nd*ml+1 demoddata2(1,n)=ich5(1,n-1)*qch5(1,n)*cos(pi*(n)0; end demodata=demoddata2(1,2:nd*ml+1); subplot(4,2,7),stairs(demodata); 名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 2 页，共 5 页 - - - - - - - - - a

8、xis(0,50,-2,2); title(恢复波形 ); %* 估计差错概率 * noe2=sum(abs(data1-demodata); nod2=length(data1); noe=noe+noe2; nod=nod+nod2; %*输出结果 * ber=noe/nod; fprintf(差错概率估计值 =%fn,noe/nod); 子程序：function iout, qout = compconv(idata, qdata, filter) iout = conv(idata,filter); qout = conv(qdata,filter); function iout,qo

9、ut = delay( idata, qdata , nsamp , idel ) iout=zeros(1,nsamp); qout=zeros(1,nsamp); if idel = 0 iout(1:idel) = zeros(1,idel); qout(1:idel) = zeros(1,idel); end iout(idel+1:nsamp) = idata(1:nsamp-idel); qout(idel+1:nsamp) = qdata(1:nsamp-idel); function iout,qout,ramp,rcos,rsin=fade(idata,qdata,nsamp

10、,tstp,fd,no,counter,flat) if fd = 0.0 ac0 = sqrt(1.0 ./ (2.0.*(no + 1); constant(ich) as0 = sqrt(1.0 ./ (2.0.*no); constant(qch) ic0 = counter; pai = 3.14159265; wm = 2.0.*pai.*fd; n = 4.*no + 2; ts = tstp; wmts = wm.*ts; paino = pai./no; xc=zeros(1,nsamp); xs=zeros(1,nsamp); 名师资料总结 - - -精品资料欢迎下载 -

11、- - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 3 页，共 5 页 - - - - - - - - - ic=1:nsamp+ic0; for nn = 1: no cwn = cos( cos(2.0.*pai.*nn./n).*ic.*wmts ); xc = xc + cos(paino.*nn).*cwn; xs = xs + sin(paino.*nn).*cwn; end cwmt = sqrt(2.0).*cos(ic.*wmts); xc = (2.0.*xc + cwmt).*ac0; xs = 2.0.*xs

12、.*as0; ramp=sqrt(xc.2+xs.2); rcos=xc./ramp; rsin=xs./ramp; if flat =1 iout = sqrt(xc.2+xs.2).*idata(1:nsamp); qout = sqrt(xc.2+xs.2).*qdata(1:nsamp); else iout = xc.*idata(1:nsamp) - xs.*qdata(1:nsamp); qout = xs.*idata(1:nsamp) + xc.*qdata(1:nsamp); end else iout=idata; qout=qdata; end function xh

13、= gaussf(B,irfn,ipoint,sr,ncc) point = ipoint; tr = sr ; n = ipoint .* irfn; mid = ( n ./ 2 ) + 1; fo=B/sqrt(2*log(2); for i = 1 : n icon = i - mid; ym = icon; xt=1/2*(erf(-sqrt(2/log(2)*pi*B*(ym/ipoint-1/2)/tr)+erf(sqrt(2/log(2)*pi*B*(ym/ipoint+1/2)/tr); if ncc = 0 % in the case of receiver xh( i )

14、 = xt ; elseif ncc = 1 % in the case of transmitter xh( i ) = xt; else error(ncc error); end 名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 4 页，共 5 页 - - - - - - - - - end function out = oversamp( indata, nsymb , sample) out=zeros(1,nsymb*sample); out(1:sample:1+samp

15、le*(nsymb-1)=indata; functioniout,qout,ramp,rcos,rsin=sefade(idata,qdata,itau,dlvl,th,n0,itn,n1,nsamp,tstp,fd,flat) iout = zeros(1,nsamp); qout = zeros(1,nsamp); total_attn = sum(10 .( -1.0 .* dlvl ./ 10.0); for k = 1 : n1 atts = 10.( -0.05 .* dlvl(k); if dlvl(k) = 40.0 atts = 0.0; end theta = th(k)

16、 .* pi ./ 180.0; itmp,qtmp = delay ( idata , qdata , nsamp , itau(k); itmp3,qtmp3,ramp,rcos,rsin=fade(itmp,qtmp,nsamp,tstp,fd,n0(k),itn(k),flat); iout = iout + atts .* itmp3 ./ sqrt(total_attn); qout = qout + atts .* qtmp3 ./ sqrt(total_attn); end 名师资料总结 - - -精品资料欢迎下载 - - - - - - - - - - - - - - - - - - 名师精心整理 - - - - - - - 第 5 页，共 5 页 - - - - - - - - -