我的毕设：卷积码的viterbi译码
这个不是最终版本，又由于很早的代码，因为怎么正确运行我也不记得了，只看代码吧加密模块encode.h//encode.h
#include <stdlib.h>
#include <time.h>
#include <math.h>
#define PI 3.14
#define length 10
#define M 3
#define N 3
void gensignal(int* origin,int mode)//产生信号
{//生成随机二进制数作为编码前的信息序列
if(mode==0) for(int i=0;i<length;i++) origin[ i]=0;//生成一位信息位
if(mode==1) for(int i=0;i<length;i++) origin[ i]=1;//生成一位信息位
if(mode==2) for(int i=0;i<length;i++) origin[ i]=i&1;//生成一位信息位
if(mode==3)
{
for(int i=0;i<length;i++) origin[ i]=rand()&1;//生成一位信息位
}
}
void encode(int encodeori,int* origin,int* generate)//编码器
{//生成卷积码,码率为1/N,一个码元有N比特
int shifter;//模拟左移移位寄存器当前状态,最大表示16位
int i,j,k,temp=shifter;
for(k=0;k<length;k++)
{//由此信息位生成N bit码元
temp=(temp<<1)^origin;//模拟移位寄存器左移
for(i=0;i<N;i++)
{//生成此卷积码码元的1bit
int sum=0,temp1=temp&generate[ i];
encodeori[ i]=0;
for(j=0;j<M;j++) sum^=(temp1>>j)&1;
//实现卷积码编码电路输入输出关系,乘矩阵的列后自模2加
encodeori[ i]=(encodeori[ i]<<1)^sum;//组合成卷积码码元
}
shifter=temp;
}
if((encodeori!=encodeori)||(encodeori!=encodeori)||(encodeori!=encodeori)) cout<<"\\\\\\\\";
}
void PSK(int encodeori,int PSKmaker)//PSK调制(1-->-1;0-->1)
{
for(int i=0;i<length;i++)
for(int j=0;j<N;j++)
{
if(encodeori[ i]) PSKmaker[ i]=-1;
else PSKmaker[ i]=1;
}
}
double gaosimaker(double DX)
{
double rand1,rand2,result;
rand1=(double)(rand())/RAND_MAX;//均匀分布
rand2=(double)(rand())/RAND_MAX;//均匀分布
result=sqrt((-2)*log(rand1))*cos(2*PI*rand2);
//变换抽样,均匀分布变为正态分布
return DX*result;
}
void addgaosi(double send,int PSKmaker,double DX)
{
for(int i=0;i<length;i++)
for(int j=0;j<N;j++)
send[ i]=PSKmaker[ i]+gaosimaker(DX);
}
int result(int x)
{
if(x=1) return 1;
else if(x>1)
{
return result(x-1)+(int)pow(10,x-1);
}
else return 65535;
}
揭秘模块decode.h
//decode.h
#include <math.h>
#include <iostream.h>
#include <stdlib>
#define length 10
#define M 3
#define N 3
#define statenum (int)pow(2,M-1)
struct fencenode{
int currentstate;//左移寄存器当前状态(...000,...001,...010,...)
int incode;//输入数据后先后到达此点的两个点分别生成的卷积码
int outcode;//outcode:输入0后生成的卷积码;outcode:输入1后生成的卷积码
fencenode* in;//输入数据后到达此点的两个点
fencenode* out;//out:输入0后从此点到达的点;out:输入1后从此点到达的点
};
struct survive{
int hamingdist;//累积汉明距离
int sufferstate;//历经状态
int outcode;//对应的原信号
};
fencenode* initstatediag(int* generate);
int dist(int dist1,int* dist2);
int distcomp(int dist1,int dist2,int* dist0,int ham1,int ham2);
void copysur(survive* mysurvivenew,survive* survive,int i);
void copysur1(survive* surv1,int m,survive* surv2,int n,int i);
survive* findmin(survive* surv,int i);
void demodulate(int demodule,double receive)//解调2PSK信号
{//硬判决,判决门限0(小于0-->1,大于0-->0)
for(int i=0;i<length;i++)
{
for(int j=0;j<N;j++)
{
if(receive[ i]<0) demodule[ i]=1;
else demodule[ i]=0;
}
}
}
survive* viterbidecoder(int demodule,int* recover,int* generate)
{
int i,j;
survive* mysurvive=new survive;//最多有状态数(statenum)个幸存路径
survive* mysurvivenew=new survive;//最多有状态数(statenum)个幸存路径
fencenode* myfence=initstatediag(generate);
for(i=0;i<statenum;i++)//对幸存路径的初始化
{
mysurvive[ i].hamingdist=0;//设置汉明初值
mysurvive[ i].sufferstate=0;//初始状态为0
mysurvivenew[ i].hamingdist=0;
mysurvivenew[ i].sufferstate=0;
for(j=0;j<length;j++)
{
mysurvive[ i].sufferstate=0;
mysurvivenew[ i].outcode=0;
mysurvive[ i].sufferstate=0;
mysurvivenew[ i].outcode=0;
}
}
for(i=1;i<=length;i++)
{//生成第i个时间段内的幸存路线片段
if(pow(2,i)<=statenum)//对应篱笆图左部下落区
{
for(j=0;j<statenum;j++)
{//生成第j状态对应的幸存路线
int temp1=(j>>(M-i))&3,temp2=(j>>(M-1-i))&1;
mysurvive.sufferstate[ i]=myfence.out->currentstate;
mysurvive.hamingdist+=dist(myfence.outcode,demodule);
mysurvive.outcode=temp2;
}
}
else
{//此篱笆图区域内每个状态必由2条路径到达,取汉明距离较小的为此时间段内此状态的幸存路径
copysur(mysurvivenew,mysurvive,i);
//准备由前一次结果重新排序幸存队列,将mysurvive赋给mysurvivenew
for(j=0;j<statenum;j++)
{
fencenode* node1=myfence.in;fencenode* node2=myfence.in;//找到转移至状态j的两个状态的地址
int code1=myfence.incode,code2=myfence.incode;
int k=distcomp(code1,code2,demodule,mysurvivenew.hamingdist,mysurvivenew.hamingdist);
if(0==k)
{//node1的距离小
copysur1(mysurvive,j,mysurvivenew,node1->currentstate,i);//赋予新路径
mysurvive.sufferstate[ i]=j;
mysurvive.hamingdist+=dist(code1,demodule);
mysurvive.outcode=j&1;
}
else if(1==k)
{//node2的距离小
copysur1(mysurvive,j,mysurvivenew,node2->currentstate,i);//赋予新路径
mysurvive.sufferstate[ i]=j;
mysurvive.hamingdist+=dist(code2,demodule);
mysurvive.outcode=j&1;
}
else
{
if(rand()<RAND_MAX/2)
{
copysur1(mysurvive,j,mysurvivenew,node1->currentstate,i);//赋予新路径
mysurvive.sufferstate[ i]=j;
mysurvive.hamingdist+=dist(code1,demodule);
mysurvive.outcode=j&1;
}
else
{
copysur1(mysurvive,j,mysurvivenew,node2->currentstate,i);//赋予新路径
mysurvive.sufferstate[ i]=j;
mysurvive.hamingdist+=dist(code2,demodule);
mysurvive.outcode=j&1;
}
}
}
}
}
survive* thebest=findmin(mysurvive,statenum);//找出statenum条路径中汉明距离最小的
for(i=0;i<statenum;i++)
{
for(j=0;j<length;j++) recover=thebest->outcode;
}
delete []mysurvive;
delete []mysurvivenew;
delete []myfence;
return mysurvive;
}
fencenode* initstatediag(int* generate)
{
fencenode* trellisdiagram=new fencenode;//网格图雏形
for(int i=0;i<statenum;i++) trellisdiagram[ i].currentstate=i;
trellisdiagram.in=&trellisdiagram;trellisdiagram.incode=0;
trellisdiagram.in=&trellisdiagram;trellisdiagram.incode=3;
trellisdiagram.out=&trellisdiagram;trellisdiagram.outcode=0;
trellisdiagram.out=&trellisdiagram;trellisdiagram.outcode=7;
trellisdiagram.in=&trellisdiagram;trellisdiagram.incode=7;
trellisdiagram.in=&trellisdiagram;trellisdiagram.incode=4;
trellisdiagram.out=&trellisdiagram;trellisdiagram.outcode=1;
trellisdiagram.out=&trellisdiagram;trellisdiagram.outcode=6;
trellisdiagram.in=&trellisdiagram;trellisdiagram.incode=1;
trellisdiagram.in=&trellisdiagram;trellisdiagram.incode=2;
trellisdiagram.out=&trellisdiagram;trellisdiagram.outcode=3;
trellisdiagram.out=&trellisdiagram;trellisdiagram.outcode=4;
trellisdiagram.in=&trellisdiagram;trellisdiagram.incode=6;
trellisdiagram.in=&trellisdiagram;trellisdiagram.incode=5;
trellisdiagram.out=&trellisdiagram;trellisdiagram.outcode=2;
trellisdiagram.out=&trellisdiagram;trellisdiagram.outcode=5;
return trellisdiagram;
}
int dist(int dist1,int* dist2)//dist1:二进制数,dist2:十进制数组,宽均为N
{
int sum=0;
switch(4*dist2+2*dist2+dist2)
{
case 0:
switch(dist1)
{
case 0:sum=0;break;
case 1: case 2: case 4:sum=1;break;
case 3: case 5: case 6:sum=2;break;
case 7:sum=3;break;
}
break;
case 1:
switch(dist1)
{
case 1:sum=0;break;
case 0: case 3: case 5:sum=1;break;
case 2: case 4: case 7:sum=2;break;
case 6:sum=3;break;
}
break;
case 2:
switch(dist1)
{
case 2:sum=0;break;
case 0: case 3: case 6:sum=1;break;
case 1: case 4: case 7:sum=2;break;
case 5:sum=3;break;
}
break;
case 3:
switch(dist1)
{
case 3:sum=0;break;
case 1: case 2: case 7:sum=1;break;
case 0: case 5: case 6:sum=2;break;
case 4:sum=3;break;
}
break;
case 4:
switch(dist1)
{
case 4:sum=0;break;
case 0: case 5: case 6:sum=1;break;
case 1: case 2: case 7:sum=2;break;
case 3:sum=3;break;
}
break;
case 5:
switch(dist1)
{
case 5:sum=0;break;
case 1: case 4: case 7:sum=1;break;
case 0: case 3: case 6:sum=2;break;
case 2:sum=3;break;
}
break;
case 6:
switch(dist1)
{
case 6:sum=0;break;
case 2: case 4: case 7:sum=1;break;
case 0: case 3: case 5:sum=2;break;
case 1:sum=3;break;
}
break;
case 7:
switch(dist1)
{
case 7:sum=0;break;
case 3: case 5: case 6:sum=1;break;
case 1: case 2: case 4:sum=2;break;
case 0:sum=3;break;
}
break;
default:break;
}
/*
int temp,sum=0,i;//按位异或
for(i=0;i<N;i++)
{
temp=((dist1>>i)&1)^dist2;
sum=sum+temp;
}//求汉明距离*/
return sum;
}
int distcomp(int dist1,int dist2,int* dist0,int ham1,int ham2)
{
if((dist(dist1,dist0)+ham1)<(dist(dist2,dist0)+ham2)) return 0;
else if((dist(dist1,dist0)+ham1)>(dist(dist2,dist0)+ham2)) return 1;
else return 2;
}
void copysur(survive* mysurvivenew,survive* mysurvive,int i)
{//将路径数组mysurvive中每个路径的前i个数据赋给mysurvivene中的每个路径
for(int j=0;j<statenum;j++)
{
for(int l=1;l<i;l++)//找到不同路径的源头
{
if(mysurvivenew.sufferstate!=mysurvive.sufferstate) break;
}
mysurvivenew.hamingdist=mysurvive.hamingdist;
for(int k=l;k<i;k++)
{
mysurvivenew.sufferstate=mysurvive.sufferstate;
mysurvivenew.outcode=mysurvive.outcode;
}
}
}
void copysur1(survive* surv1,int m,survive* surv2,int n,int i)
{//将路径surv2的前i个数据赋给surv1,变成新的surv1
for(int l=1;l<i;l++)//找到不同路径的源头
{
if(surv1.sufferstate!=surv2.sufferstate) break;
}
surv1.hamingdist=surv2.hamingdist;
for(int k=l;k<i;k++)
{
surv1.sufferstate=surv2.sufferstate;
surv1.outcode=surv2.outcode;
}
}
survive* findmin(survive* surv,int i)//在i个路径中找汉明距离最小的
{
int j,k=0,best=0,smaller=surv.hamingdist;
for(j=0;j<i;j++)
{
if(surv.hamingdist<smaller) {smaller=surv.hamingdist;best=j;}
/*
else if(surv.hamingdist=smaller)
{
if(rand()&1) best=j;
}*/
}
return &surv;
}
int pe(int* origin,int* recover)
{
int i,sum=0;
for(i=0;i<length;i++)
if(origin[ i]!=recover[ i]) return 1;
return 0;
}
主模块
//main.cpp
//卷积码(N,1,M)的viterbi译码
#include <iostream.h>
#include "encode.h"
#include "decode.h"
#include <stdlib.h>
#include <math.h>
#include <iomanip.h>
#define length 10
#define M 3
#define N 3
#define statenum (int)pow(2,M-1)
int generate={1,5,7};//001,101,111
int origin;
//encodeori由信息位生成卷积码,码率为1/N,一个码元有N比特
int encodeori;
//PSKmaker将卷积码调制成PSK信号
int PSKmaker;
//send加入高斯白噪声后的信号
double send;
//从信道里接收的信号
int demodule;
//解码后的信号;由statenum个幸存路径筛选得出
int recover;
int viterbikey(double DX,int mode)
{
gensignal(origin,mode);
encode(encodeori,origin,generate);//产生信号
PSK(encodeori,PSKmaker);//PSK调制
addgaosi(send,PSKmaker,DX);//加高斯白噪声
demodulate(demodule,send);//解调
survive* sur=viterbidecoder(demodule,recover,generate);
int PE=pe(origin,recover);
return PE;
}
double viterbi()
{
int mode=3,sum=0,i,j,k;
double DX=1.0;
for(i=0;i<100;i++)
{
if(viterbikey(DX,mode)==1)
{
sum=sum+1;
cout<<"origin: ";
for(j=0;j<length;j++) cout<<origin;
cout<<endl<<"encodeori: ";
for(j=0;j<length;j++)
{
for(k=0;k<N;k++) cout<<encodeori;
cout<<" ";
}
cout<<endl<<"PSKmaker: ";
for(j=0;j<length;j++)
{
for(k=0;k<N;k++) cout<<;PSKmaker;
cout<<" ";
}
cout<<endl<<"send ";
for(j=0;j<length;j++)
{
for(k=0;k<N;k++) cout<<setprecision(2)<<send<<" ";
cout<<"";
}
cout<<endl<<"demodule: ";
for(j=0;j<length;j++)
{
for(k=0;k<N;k++) cout<<demodule;
cout<<" ";
}
cout<<endl<<"recover: ";
for(j=0;j<length;j++) cout<<recover;
cout<<endl<<endl;
}
}
return 1.0*sum/1000;
}
void main()
{
unsigned long seed;
time((long*)&seed);
srand(seed);
cout<<"误码率为： "<<viterbi()<<endl;
}
matlab版
length=1000;M=3;N=3;statenum=2^(M-1);error=zeros(1,101);
for xyz=1:1:101
DX=(xyz-1)/10;
origin=randi(,1,length);generate=;
encodeori=zeros(length,N);PSKmaker=zeros(length,N);
send=zeros(length,N);demodule=zeros(length,N);recover=zeros(1,length);
shift=zeros(length,M);
shift(1,M)=origin(1);
for i=2:1:length
shift(i,:)=;
end
encodeori=mod(shift*generate,2);
PSKmaker=ones(size(encodeori))-encodeori*2;
send=PSKmaker+DX*randn(size(PSKmaker));
demodule=send<0;
shift=zeros(statenum,1,2*M-3);
for i=1:1:statenum
j=i-1;k=0;
while j~=0
shift(i,1,end-k)=mod(j,2);
j=bitshift(j,-1);
k=k+1;
end
end
arraytonum=ones(M-1,1);
for i=M-1:-1:2
arraytonum(i-1)=2*arraytonum(i);
end
shift1=squeeze(shift(:,:,end-M+2:end));
myfence.incode(1).value=mod(*generate,2);
myfence.incode(2).value=mod(*generate,2);
mysurvive.hamingdist=zeros(statenum,length);
mysurvive.sufferstate=zeros(statenum,length+1,M-1);
mysurvive.outcode=zeros(statenum,length);
for i=2:1:M
mysurvive.sufferstate(:,i,:)=shift(:,1,(i-1):(i+M-3));
end
mysurvive.outcode(:,1:M-1)=shift1;
mysurvive.sufferstate1=cat(3,zeros(statenum,M-1,1),mysurvive.sufferstate(:,2:M,:));
mysurvive.hamingdist(:,1)=sum(mod(squeeze(mysurvive.sufferstate1(:,1,:))*generate,2)~=(ones(statenum,1)*demodule(1,:)),2)';
for i=2:1:M-1
mysurvive.hamingdist(:,i)=sum(mod(squeeze(mysurvive.sufferstate1(:,i,:))*generate,2)~=(ones(statenum,1)*demodule(i,:)),2)+mysurvive.hamingdist(:,i-1);
end
for i=M:1:length
mysurvivenew=mysurvive;
for j=1:1:statenum
mysurvive.outcode(j,i)=mod(j-1,2);
mysurvive.sufferstate(j,i+1,:)=shift1(j,:);
state1=*arraytonum+1;state2=*arraytonum+1;
dist1=sum(myfence.incode(1).value(j,:)~=demodule(i,:))+mysurvivenew.hamingdist(state1,i-1);
dist2=sum(myfence.incode(2).value(j,:)~=demodule(i,:))+mysurvivenew.hamingdist(state2,i-1);
if (dist1<dist2)||((dist1==dist2)&&(randi()==0))
mysurvive.outcode(j,1:i-1)=mysurvivenew.outcode(state1,1:i-1);
mysurvive.sufferstate(j,2:i,:)=mysurvivenew.sufferstate(state1,2:i,:);
mysurvive.hamingdist(j,1:i-1)=mysurvivenew.hamingdist(state1,1:i-1);
mysurvive.hamingdist(j,i)=dist1;
else
mysurvive.outcode(j,1:i-1)=mysurvivenew.outcode(state2,1:i-1);
mysurvive.sufferstate(j,2:i,:)=mysurvivenew.sufferstate(state2,2:i,:);
mysurvive.hamingdist(j,1:i-1)=mysurvivenew.hamingdist(state2,1:i-1);
mysurvive.hamingdist(j,i)=dist2;
end
end
end
thebest=min(find(mysurvive.hamingdist(:,end)==min(mysurvive.hamingdist(:,end))));
recover=mysurvive.outcode(thebest,:);
error(xyz)=sum(recover~=origin)/length;
end
plot(linspace(0,10,101),error)
length=1000;M=3;N=5;statenum=2^(M-1);error=zeros(1,101);
for xyz=1:1:101
DX=(xyz-1)/10;
origin=randi(,1,length);generate=;
encodeori=zeros(length,N);PSKmaker=zeros(length,N);
send=zeros(length,N);demodule=zeros(length,N);recover=zeros(1,length);
shift=zeros(length,M);
shift(1,M)=origin(1);
for i=2:1:length
shift(i,:)=;
end
encodeori=mod(shift*generate,2);
PSKmaker=ones(size(encodeori))-encodeori*2;
send=PSKmaker+DX*randn(size(PSKmaker));
demodule=send<0;
shift=zeros(statenum,1,2*M-3);
for i=1:1:statenum
j=i-1;k=0;
while j~=0
shift(i,1,end-k)=mod(j,2);
j=bitshift(j,-1);
k=k+1;
end
end
arraytonum=ones(M-1,1);
for i=M-1:-1:2
arraytonum(i-1)=2*arraytonum(i);
end
shift1=squeeze(shift(:,:,end-M+2:end));
myfence.incode(1).value=mod(*generate,2);
myfence.incode(2).value=mod(*generate,2);
mysurvive.hamingdist=zeros(statenum,length);
mysurvive.sufferstate=zeros(statenum,length+1,M-1);
mysurvive.outcode=zeros(statenum,length);
for i=2:1:M
mysurvive.sufferstate(:,i,:)=shift(:,1,(i-1):(i+M-3));
end
mysurvive.outcode(:,1:M-1)=shift1;
mysurvive.sufferstate1=cat(3,zeros(statenum,M-1,1),mysurvive.sufferstate(:,2:M,:));
mysurvive.hamingdist(:,1)=sum(mod(squeeze(mysurvive.sufferstate1(:,1,:))*generate,2)~=(ones(statenum,1)*demodule(1,:)),2)';
for i=2:1:M-1
mysurvive.hamingdist(:,i)=sum(mod(squeeze(mysurvive.sufferstate1(:,i,:))*generate,2)~=(ones(statenum,1)*demodule(i,:)),2)+mysurvive.hamingdist(:,i-1);
end
for i=M:1:length
mysurvivenew=mysurvive;
for j=1:1:statenum
mysurvive.outcode(j,i)=mod(j-1,2);
mysurvive.sufferstate(j,i+1,:)=shift1(j,:);
state1=*arraytonum+1;state2=*arraytonum+1;
dist1=sum(myfence.incode(1).value(j,:)~=demodule(i,:))+mysurvivenew.hamingdist(state1,i-1);
dist2=sum(myfence.incode(2).value(j,:)~=demodule(i,:))+mysurvivenew.hamingdist(state2,i-1);
if (dist1<dist2)||((dist1==dist2)&&(randi()==0))
mysurvive.outcode(j,1:i-1)=mysurvivenew.outcode(state1,1:i-1);
mysurvive.sufferstate(j,2:i,:)=mysurvivenew.sufferstate(state1,2:i,:);
mysurvive.hamingdist(j,1:i-1)=mysurvivenew.hamingdist(state1,1:i-1);
mysurvive.hamingdist(j,i)=dist1;
else
mysurvive.outcode(j,1:i-1)=mysurvivenew.outcode(state2,1:i-1);
mysurvive.sufferstate(j,2:i,:)=mysurvivenew.sufferstate(state2,2:i,:);
mysurvive.hamingdist(j,1:i-1)=mysurvivenew.hamingdist(state2,1:i-1);
mysurvive.hamingdist(j,i)=dist2;
end
end
end
thebest=min(find(mysurvive.hamingdist(:,end)==min(mysurvive.hamingdist(:,end))));
recover=mysurvive.outcode(thebest,:);
error(xyz)=sum(recover~=origin)/length;
end
plot(linspace(0,10,101),error)
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