matlab直扩仿真代码

1、1.在AWGN信道下对直扩通信系统进行性能仿真研究%100kHz40MHz5MHzclose allclear all %SNR=1:1:15Rb=0.25; %0.25Mb/sTb=1/Rb; %M=100; %L=400; %N=M*L; %dt=Tb/L; %df=1/(N*dt); %Bs=N*df/2; %T=N*dt; %t=linspace(-T/2,T/2,N); % x=sign(rand(1,M)-0.5); %t0=linspace(0,T,M);for i=1:100; d(1+(i-1)*400):i*400)=x(i); %400endfigure(1)plot(t

2、,d)xlabel(t(ms);ylabel(s(t)(V);title();axis(0,200,-1.5,1.5);grid on %fs=4000; %kHzz=reshape(d,2,N/2); %Q=z(1,:); %s,Q(t)I=z(2,:); %s,I(t)tq=linspace(-T/2,T/2,length(I);QPSK=(I.*cos(2*fs*pi*tq)-Q.*sin(2*fs*pi*tq)/sqrt(2); %QPSKfigure(2)plot(tq,QPSK)xlabel(t(ms);ylabel(QPSK(t)(V);title(QPSK);axis(0,20

3、0,-1.5,1.5);grid on %user=1; %seq=1; %1m 2Gold 3Goldstage=3; %ptap1=1 3; %1 3ptap2=2 3; %2 3regi1=1 1 1; %1 1 1regi2=1 1 1; %1 1 1switch seq case 1 %m code=mseq(stage,ptap1,regi1,user); case 2 %Gold m1= mseq(stage,ptap1,regi1); m2= mseq(stage,ptap2,regi2); code=goldseq(m1,m2,user); case 3 %Gold m1=m

4、seq(stage,ptap1,regi1); m2=mseq(stage,ptap2,regi2); code=goldseq(m1,m2,user),zeros(user,1); end xxx=code clen=length(code);xlength=100*50; %50x_code=zeros(1,xlength);for i=1:xlength %0,1-1,1 if mod(i,7)=0 %mod(a,b)ab x_code(i)=sign(code(mod(i,7)-0.5); elseif mod(i,7)=0 x_code(i)=sign(code(7)-0.5); e

5、ndendk_code=zeros(1,length(QPSK);for i=1:5000 k_code(1+(i-1)*4):i*4)=x_code(i); %4endfigure(3)plot(tq,k_code)xlabel(t(ms);ylabel(k_code(t)(V);title();axis(20,25,-1.5,1.5);grid on %b=QPSK.*k_code; %fc=4e4; %kHztd=linspace(0,T,length(b);%blinspace linlinearx=linspace(a,b,n)ab ns=b.*cos(2*fc*pi*td);fig

6、ure(4)plot(td,s)xlabel(t(ms);ylabel(s(t)(V);title();axis(20,31,-1.5,1.5);grid on %r= awgn(s,SNR(10),measured);% %rs=r.*cos(2*fc*pi*td);figure(5)plot(td,rs)xlabel(t(ms);ylabel(rs(t)(V);title();axis(20,28,-1.5,1.5);grid on %jk_code=rs.*k_code;figure(6)plot(td,jk_code)xlabel(t(ms);ylabel(rk(t)(V);title

7、();axis(20,33,-1.5,1.5);grid onf,rf=T2F(td,jk_code); %tl,l=lpf(f,rf,fc/10000); % %liremod=cos(2*fs*pi*tq)*sqrt(2).*l; %Ifi,lif=T2F(tq,liremod);tji,iremod=lpf(fi,lif,fs/10000); %iremodo=sign(iremod); %lqremod=(-1)*sin(2*fs*pi*tq)*sqrt(2).*l; %Q fq,lqf=T2F(tq,lqremod); tjq,qremod=lpf(fq,lqf,fs/10000);

8、 %qremodo=sign(qremod); %zl=qremodo,iremodo; %figure(7)plot(t,zl)xlabel(t(ms);ylabel(zl(t)(V);title();axis(0,200,-1.5,1.5);grid on z2=0;xo=zeros(size(x);for i=1:100 z2=0 for j=1+(i-1)*400:i*400 z2=z2+zl(j); end if z2=0 xo(i)=1; else xo(i)=-1; endend figure(8)plot(t0,xo)xlabel(t(ms);ylabel(xo(t)(V);t

9、itle();axis(0,400,-1.5,1.5);grid on for a=1:15 r= awgn(s,SNR(a),measured);% rs=r.*cos(2*fc*pi*td); jk_code=rs.*k_code; f,rf=T2F(td,jk_code); %tl,l=lpf(f,rf,fc/10000); %liremod=cos(2*fs*pi*tq)*sqrt(2).*l; %Ifi,lif=T2F(tq,liremod);tji,iremod=lpf(fi,lif,fs/10000); %iremodo=sign(iremod); %lqremod=(-1)*s

10、in(2*fs*pi*tq)*sqrt(2).*l; %Q fq,lqf=T2F(tq,lqremod); tjq,qremod=lpf(fq,lqf,fs/10000); %qremodo=sign(qremod); %zl=qremodo,iremodo; %z2=0;xo=zeros(size(x);for i=1:100 z2=0 for j=1+(i-1)*400:i*400 z2=z2+zl(j); end if z2=0 xo(i)=1; else xo(i)=-1; endend z=0;for i=1:100 if(x(i)=xo(i) z=z+1; endendz1(a)=

11、z/100endfigure(8)plot(SNR,z1)xlabel(SNR);ylabel(z1);title();axis(0,15,10(-4),1);grid on1. ifuser=1 2. ich4=ich3; 3. qch4=qch3; 4. else 5. ich4=sum(ich3); 6. qch4=sum(qch3); 7. end 8. %+ 9. 10. %+衰减信道+ 11. ifrfade=0 12. ich5=ich4; 13. qch5=qch4; 14. else 15. ich5,qch5=sefade(ich4,qch4,itau,dlvl1,th1,

12、n0,itnd1, 16. now1,length(ich4),tstp,fd,flat); 17. itnd1itnd1=itnd1+itndel; 18. end 19. %+ 20. 21. %+接收机+ 22. spow=sum(rot90(ich3.2+qch3.2)/nd;%衰减计算 23. attn=sqrt(0.5*spow*sr/br*10(-ebn0/10); 24. 25. ich6,qch6=comb2(ich5,qch5,attn);%添加高斯白噪声(AWGN) 26. ich7,qch7=compconv2(ich6,qch6,xh2);%滤波 27. 28. sa

13、mpl=irfn*IPOINT+1; 29. ich8=ich7(:,sampl:IPOINT:IPOINT*nd*clen+sampl-1); 30. qch8=qch7(:,sampl:IPOINT:IPOINT*nd*clen+sampl-1); 31. 32. ich9qch9=despread(ich8,qch8,code);%解扩 33. 34. demodata=qpskdemod(ich9,qch9,user,nd,ml);%QPSK解调 35. %+ 36. 37. %+误码率分析+ 38. 39. noe2=sum(sum(abs(data-demodata); 40. n

14、od2=user*nd*ml; 41. noenoe=noe+noe2; 42. nodnod=nod+nod2; 43. 44. %fprintf(%dt%en,ii,noe2/nod2); 45. 46. end 47. %+ 48. 49. %+数据文件+ 50. ber=noe/nod; 51. fprintf(%dt%dt%dt%en,ebn0,noe,nod,noe/nod); 52. fid=fopen(BER.dat,a); 53. fprintf(fid,%dt%et%ft%ftn,ebn0,noe/nod,noe,nod); 54. fclose(fid); 55. err

15、_rate_final(ebn0+6)=ber; 56. end 57. %+ 58. 59. %+性能仿真图+ 60. figure 61. semilogy(SNR,err_rate_final,b-*); 62. xlabel(信噪比/dB) 63. ylabel(误码率) 64. axis(-5,10,0,1) 65. gridon 66. 67. disp(-end-); 68. %+ 69. 70. 71. %*beginningoffile* 72. %hrollfcoef.m 73. % 74. %此函数用于产生Nyquist滤波器的系数 75. % 76. 77. 78. f

16、unctionxh=hrollfcoef(irfn,ipoint,sr,alfs,ncc) 79. 80. 81. %+variables+ 82. %irfn用于滤波的符号数 83. %ipoint每个符号的抽样值数 84. %sr符号速率 85. %alfs衰减截止频率 86. %ncc1-发送端滤波0-接收端滤波 87. %+ 88. 89. xi=zeros(1,irfn*ipoint+1); 90. xq=zeros(1,irfn*ipoint+1); 91. 92. point=ipoint; 93. tr=sr; 94. tstp=1.0./tr./ipoint; 95. n=i

17、point.*irfn; 96. mid=(n./2)+1; 97. sub1=4.0.*alfs.*tr; 98. 99. fori=1:n 100. 101. iicon=i-mid; 102. ym=icon; 103. 104. ificon=0.0 105. xtalfs./pi).*tr; 106. else 107. sub2=16.0.*alfs.*alfs.*ym.*ym./ipoint./ipoint; 108. ifsub2=1.0 109. x1=sin(pi*(1.0-alfs)/ipoint*ym)./pi./(1.0-sub2)./ym./tstp; 110. x

18、2=cos(pi*(1.0+alfs)/ipoint*ym)./pi.*sub1./(1.0-sub2); 111. xt=x1+x2; 112. else 113. xt=alfs.*tr.*(1.0-2.0/pi).*cos(pi/4.0/alfs)+(1.0+2.0./pi). 114. *sin(pi/4.0/alfs)./sqrt(2.0); 115. end 116. end 117. 118. ifncc=0%当接收机情况 119. xh(i)=xt./ipoint./tr; 120. elseifncc=1%当发射机情况 121. xh(i)=xt./tr; 122. else

19、 123. error(nccerror); 124. end 125. 126. end 127. 128. %*endoffile* 129. 130. 131. %*beginningoffile* 132. %mseq.m 133. % 134. %此函数产生m序列 135. % 136. %试举一例： 137. %stg=3 138. %taps=1,3 139. %inidata=1,1,1 140. %n=2 141. % 142. 143. 144. functionmout=mseq(stg,taps,inidata,n) 145. 146. %+variables+ 147

20、. %stgm序列阶数 148. %taps线性移位寄存器的系数 149. %inidata序列的初始化 150. %n输出序列的数目 151. %mout输出的m序列 1. %+2. ifnargin1 22. forii=2:n 23. mout(ii,:)=shift(mout(ii-1,:),1,0); 24. end 25. end 26. 27. %*endoffile* 28. 29. 30. %*beginningoffile* 31. %shift.m 32. % 33. %此函数用于实现线性移位寄存器的移位操作 34. % 35. 36. functionoutregi=s

21、hift(inregi,shiftr,shiftu) 37. 38. %+variables+ 39. %inrege向量或矩阵 40. %shiftr右移量 41. %shiftu顶部移位量 42. %outregi寄存器的输出 43. %+ 44. 45. h,v=size(inregi); 46. outregi=inregi; 47. 48. shiftr=rem(shiftr,v); 49. shiftu=rem(shiftu,h); 50. 51. ifshiftr0 52. outregi(:,1:shiftr)=inregi(:,v-shiftr+1:v); 53. outre

22、gi(:,1+shiftr:v)=inregi(:,1:v-shiftr); 54. elseifshiftr0 62. outregi(1:h-shiftu,:)=inregi(1+shiftu:h,:); 63. outregi(h-shiftu+1:h,:)=inregi(1:shiftu,:); 64. elseifshiftu0 65. outregi(1:-shiftu,:)=inregi(h+shiftu+1:h,:); 66. outregi(1-shiftu:h,:)=inregi(1:h+shiftu,:); 67. end 68. 69. %*endoffile* 70.

23、 71. 72. %*beginningoffile* 73. %goldseq.m 74. % 75. %此函数用于产生gold序列 76. % 152.1. functiongout=goldseq(m1,m2,n) 2. 3. %+variables+ 4. %m1第一个m序列 5. %m2第二个m序列 6. %n输出序列的数目 7. %gout输出产生的gold序列 8. %+ 9. 10. ifnarginhc 98. error(lackofspreadcodesequences); 99. end 100. 101. iout=zeros(hn,vn*vc); 102. qout

24、=zeros(hn,vn*vc); 103. 104. forii=1:hn 105. iout(ii,:)=reshape(rot90(code1(ii,:),3)*idata(ii,:),1,vn*vc); 106. qout(ii,:)=reshape(rot90(code1(ii,:),3)*qdata(ii,:),1,vn*vc); 107. end1. %*endoffile* 2. 3. 4. %*beginningoffile* 5. %compoversamp2.m 6. % 7. %此函数实现sample倍升采样 8. % 9. 10. functioniout,qout=

25、compoversamp2(iin,qin,sample) 11. 12. %+variables+ 13. %iin输入序列实部 14. %qin输入序列虚部 15. %iout输出序列实部 16. %qout输出序列虚部 17. %sample升采样的倍数 18. %+ 19. 20. h,v=size(iin); 21. 22. iout=zeros(h,v*sample); 23. qout=zeros(h,v*sample); 24. 25. iout(:,1:sample:1+sample*(v-1)=iin; 26. qout(:,1:sample:1+sample*(v-1)=

26、qin; 27. 28. %*endoffile* 29. 30. 31. %*beginningoffile* 32. %compconv2.m 33. % 34. %此函数用于实现有用信号的滤波 35. % 36. 37. 38. functioniout,qout=compconv2(idata,qdata,filter) 39. 40. %+variables+ 41. %idata输入序列实部 42. %qdata输入序列虚部 43. %iout输出序列实部 44. %qout输出序列虚部 45. %filter滤波器的系数 46. %+ 47. iout=conv2(idata,f

27、ilter); 48. qout=conv2(qdata,filter); 49. 50. %*endoffile* 51. 52. 53. %*beginningoffile* 54. %sefade.m 55. % 56. %此函数用于实现信道的频率选择性衰落设计 57. % 58. 59. 60. functioniout,qout,ramp,rcos,rsin=sefade 61. (idata,qdata,itau,dlvl,th,n0,itn,n1,nsamp,tstp,fd,flat) 62. 63. %+variables+ 64. %idata输入的实部数据 65. %qda

28、ta输入的虚部数据 66. %iout输出的实部数据 67. %qout输出的虚部数据 68. %ramp幅度衰减 69. %rcos正交分量衰减 70. %rsin同相分量衰减 71. %itau各径时延 72. %dlvl各多径衰减量 73. %th各多径初始相位 74. %n0用于产生各径衰落的波数 75. %itn各多径衰减计数 76. %n1主径和各延迟波形总数 77. %nsamp符号数 78. %tstp最小时间分辨率 79. %fd最大多普勒频移 80. %flat是否是平坦衰落 81. %(1-flat(只有幅度衰落),0-nomal(相位和幅度都衰落) 82. %+1. iout=zeros(1,nsamp); 2. qout=zeros(1,nsamp); 3. 4. total_attn=sum(10.(-1.0.*dlvl./10.0); 5. 6. fork=1:n1 7. 8. atts=10.(-0.05.*dlvl(k); 9. 10. ifdlvl(k)=40.0 11. atts=0.0; 12. end 13. 14. tht