8PSK在matlab上的调制解调及误码率计算

function[pb,ps]=cm_sm32(snr_in_dB) %[pb,ps]=cm_sm32(snr_in_dB) % CM_SM32求出QPSK以dB为单位的给定信噪比的 % 比特误码率和符号误码率 N=10000; E=1; %每符号能量 snr=10^(snr_in_dB/10); %信噪比 sgma=sqrt(E/(3*2*snr)); %噪声标准方差 %信号映射 s000=[1,0]; s001=[cos(pi/4),sin(pi/4)]; s010=[cos(3*pi/4),sin(3*pi/4)]; s011=[0,1]; s100=[cos(7*pi/4),sin(7*pi/4)]; s101=[0,-1]; s110=[-1,0]; s111=[cos(5*pi/4),sin(5*pi/4)]; %数据源的产生 for i=1:N, temp=rand; %在区间（0，1 )间的一个均匀随机变量 if (temp<0.125), %信源输出为“000”的概率为1/8 dsource1(i)=0; dsource2(i)=0; dsource3(i)=0; elseif (temp<0.25), %信源输出为“001”的概率为1/8 dsource1(i)=0; dsource2(i)=0; dsource3(i)=1; elseif (temp<0.375), %信源输出为“010”的概率为1/8 dsource1(i)=0; dsource2(i)=1; dsource3(i)=0; elseif (temp<0.5), %信源输出为“011”的概率为1/8 dsource1(i)=0; dsource2(i)=1; dsource3(i)=1; elseif (temp<0.625), %信源输出为“100”的概率为1/8 dsource1(i)=1; dsource2(i)=0; dsource3(i)=0; elseif (temp<0.75), %信源输出为“101”的概率为1/8 dsource1(i)=1; dsource2(i)=0; dsource3(i)=1; elseif (temp<0.875), %信源输出为“110”的概率为1/8 dsource1(i)=1; dsource2(i)=1; dsource3(i)=0; else %信源输出为“111”的概率为1/8 dsource1(i)=1; dsource2(i)=1; dsource3(i)=1; end; end; %判决、误码率的计算 numofsymbolerror=0; numofbiterror=0; for i=1:N, %在判决器处的接收信号，对于第i个符号为： n(1)=gngauss(sgma); n(2)=gngauss(sgma); if ((dsource1(i)==0) & (dsource2(i)==0) & (dsource3(i)==0)), r=s000+n; elseif ((dsource1(i)==0) & (dsource2(i)==0) & (dsource3(i)==1)), r=s001+n; elseif ((dsource1(i)==0) & (dsource2(i)==1) & (dsource3(i)==0)), r=s010+n; elseif ((dsource1(i)==0) & (dsource2(i)==1) & (dsource3(i)==1)), r=s011+n; elseif ((dsource1(i)==1) & (dsource2(i)==0) & (dsource3(i)==0)), r=s100+n; elseif ((dsource1(i)==1) & (dsource2(i)==0) & (dsource3(i)==1)), r=s101+n; elseif ((dsource1(i)==1) & (dsource2(i)==1) & (dsource3(i)==0)), r=s110+n; else r=s111+n; end; %以下为计算互相关量度 c000=dot(r , s000); c001=dot(r , s001); c010=dot(r , s010); c011=dot(r , s011); c100=dot(r , s100); c101=dot(r , s101); c110=dot(r , s110); c111=dot(r , s111); %第i个符号的判决按如下方式进行 c_max=max([c000 c001 c010 c011 c100 c101 c110 c111]); if (c000==c_max) decis1=0;decis2=0;decis3=0; elseif (c001==c_max) decis1=0;decis2=0;decis3=1; elseif (c010==c_max) decis1=0;decis2=1;decis3=0; elseif (c011==c_max) decis1=0;decis2=1;decis3=1; elseif (c100==c_max) decis1=1;decis2=0;decis3=0; elseif (c101==c_max) decis1=1;decis2=0;decis3=1; elseif (c110==c_max) decis1=1;decis2=1;decis3=0; else decis1=1;decis2=1;decis3=1; end; %如果判决不对，计错器加1 symbolerror=0; if (decis1~=dsource1(i)), numofbiterror=numofbiterror+1; symbolerror=1; end; if (decis2~=dsource2(i)), numofbiterror=numofbiterror+1; symbolerror=1; end; if (decis3~=dsource3(i)), numofbiterror=numofbiterror+1; symbolerror=1; end; if (symbolerror==1), numofsymbolerror=numofsymbolerror+1; end; end; ps=numofsymbolerror/N; %因为总共有N个符号 pb=numofbiterror/(3*N); %因为发送了3N个比特 clear all echo off SNRindB1=0:2:10; SNRindB2=0:0.1:10; for i=1:length (SNRindB1), [pb , ps]=cm_sm32 (SNRindB1 (i)); %仿真比特和符号误码率 smld_bit_err_prb (i)=pb; smld_symbol_err_prb (i)=ps; end; for i=1:length (SNRindB2), SNR=exp(SNRindB2(i)*log(10)/10); %信噪比 theo_err_prb(i)=2*Qfunct(sqrt(6*SNR)*sin(pi/8))/3; %理论比特误码率 end; %%%%%%%随后绘图曲线%%%%%%% semilogy (SNRindB1,smld_bit_err_prb,'*'); hold semilogy (SNRindB1,smld_symbol_err_prb,'O'); semilogy (SNRindB2,theo_err_prb); grid on xlabel('Eb/No in dB') ylabel('error probability') title('8PSK系统的蒙特卡罗仿真') %gtext('（注：“—”理论误码率；“*”误比特率；“o”误符号率）') clear clear all N=21; bit_sequence=rand(1,N)>0.5; bpsk=bit_sequence*2-1; temp=[0.5+1j 1+0.5j -0.5+1j -1+0.5j -0.5-1j -1-0.5j 0.5-1j 1-0.5j]/sqrt(3); transformbit = [0 0 0]; qpsk_sequence = ones(1,N/3); psk_dianpingi=ones(1,N/3); psk_dianpingq=ones(1,N/3); for k=1:N/3 transformbit = bit_sequence(3*k-2:3*k); if transformbit== [0 0 0] qpsk_sequence(k) = temp(1); ge(k)=conj(temp(1)); psk_dianpingi(k)=-0.383; psk_dianpingq(k)=-0.924; end if transformbit== [0 0 1] qpsk_sequence(k) = temp(2); ge(k)=conj(temp(2)) ; psk_dianpingi(k)=-0.924; psk_dianpingq(k)=-0.383; end if transformbit== [0 1 0] qpsk_sequence(k) = temp(3); ge(k)=conj(temp(3)); psk_dianpingi(k)=-0.383; psk_dianpingq(k)=0.924; end if transformbit== [0 1 1] qpsk_sequence(k) = temp(4); ge(k)=conj(temp(4)); psk_dianpingi(k)=-0.924; psk_dianpingq(k)=0.383; end if transformbit== [1 0 0] qpsk_sequence(k) = temp(5); ge(k)=conj(temp(5)); psk_dianpingi(k)=0.383; psk_dianpingq(k)=-0.924; end if transformbit== [1 0 1] qpsk_sequence(k) = temp(6); ge(k)=conj(temp(6)); psk_dianpingi(k)=0.924; psk_dianpingq(k)=-0.383; end if transformbit== [1 1 0] qpsk_sequence(k) = temp(7); ge(k)=conj(temp(7)) psk_dianpingi(k)=0.383; psk_dianpingq(k)=0.924; end if transformbit== [1 1 1] qpsk_sequence(k) = temp(8); ge(k)=conj(temp(8)); psk_dianpingi(k)=0.924; psk_dianpingq(k)=0.383; end x(k)=(qpsk_sequence(k)+ge(k))/2 ; y(k)=(qpsk_sequence(k)-ge(k))/2j; t=3*k-3:0.01:3*k; x1=(psk_dianpingi(k)*cos(2*pi*psk_dianpingi(k)*t)-psk_dianpingq(k)*sin(2*pi*t)); subplot(4,1,4) axis([0,N-2,-2.5,2.5]) plot(t,x1);hold on xx=bit_sequence(1); for ii=1:N; for kk=ii:0.01:ii+1; b=ones(1,100); subplot(4,1,1); plot(kk,bit_sequence(ii));axis([0,N+1,-2,2]);hold on if bit_sequence(ii)~=xx; aa=0:0.01:1;plot(ii,aa); end xx=bit_sequence(ii); end end end xxx=psk_dianpingi(1); for iii=3:3:21 for kkk=iii:0.01:iii+3 b=ones(1,100); subplot(4,1,2) jjj=iii/3; plot(kkk,psk_dianpingi(jjj));axis([0,21,-2,2]);hold on ccc=psk_dianpingi(jjj); if ccc~=xxx; if xxx<ccc aaa=xxx:0.01:ccc;plot(iii,aaa,'-b'); else aaa=xxx:-0.01:ccc;plot(iii,aaa,'-b'); end end xxx=psk_dianpingi(jjj); end end xxxx=psk_dianpingq(1); for iiii=3:3:21; for kkkk=iiii:0.01:iiii+3 b=ones(1,100); subplot(4,1,3) jjjj=iiii/3; plot(kkkk,psk_dianpingq(jjjj));axis([0,21,-2,2]);hold on cccc=psk_dianpingq(jjjj); if cccc~=xxxx; if xxxx<cccc aaaa=xxxx:0.01:cccc;plot(iiii,aaaa,'-b'); else aaaa=xxxx:-0.01:cccc;plot(iiii,aaaa,'-b'); end end xxxx=psk_dianpingq(jjjj); end end subplot(4,1,4);title('8psk调制波形') subplot(4,1,1);title('随机二进制序