?? turbode.cpp
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/*Turbo碼譯碼程序，2006-08-29。使用Log-MAP譯碼算法，在譯碼中不使用尾比特*/
#include<math.h>
//#include<time.h>
//#include<stdlib.h>
#include<iostream.h>
#include <fstream.h>
ofstream myf("d:\\WCDMA.txt", ios::trunc);
//variable
int tmp;
const int block_size=40; //碼塊長度
int niter=10; //迭代的次數(shù)
double * rx_data; //接收到的數(shù)據(jù)
double SNR_db;
double SNR;
double rate=(double)1/3;
double *rx_s1;
double *rx_s2;
double *rx_p1;
double *rx_p2; //接收到的信息比特1,信息比特2，校驗比特1，校驗比特2,信息比特2和信息比特1相同
double *ext1,*ext2; //譯碼器1輸出的外信息，譯碼器2輸出的外信息
//int *de_data;//譯碼輸出的數(shù)據(jù)
int de_data[block_size];
double **alpha,**beta; //前項路徑度量，反向路徑度量
double **gama; //分支度量
double Lc; //信道置信度 Lc=4*(Es/N0)
int const Infty_1=32767; //表示無窮大,用于限制alpha，beta
int const Infty_2=8191; //表示無窮大，用于限制gamma
int *intlv_array; //交織數(shù)組
int *de_intlv_array; //解交織數(shù)組
//function
void decode_init(); //初始化
void turbo_decode(); //譯碼調(diào)度函數(shù)
void log_map_ext(double *rx_s,double *rx_p,double *ext_in,double *ext_out); //Log-MAP譯碼算法,計算外信息
void log_map_llr(double *rx_s,double *rx_p,double *ext_in,double *llr); //Log-MAP譯碼算法，計算對數(shù)似然比
int max(int a,int b); //比較a和b的最大值并返回
double max(double a,double b); //比較a和b的最大值并返回
int gcd(int a, int b); //判斷a和b是否互質(zhì)，返回1:互質(zhì)；0：不互質(zhì)
double max_star(double a, double b); //計算max star 運算 max*(a,b)=max(a,b)+log(1+exp(-abs(a-b))
void creat_interleaver(); //產(chǎn)生交織數(shù)組和解交織數(shù)組
void interleaver(int *data); //交織
void deinterleaver(int *data); //解交織
void interleaver(double *data); //交織
void deinterleaver(double *data); //解交織
void decision(double *indata); //判決
void freemem(); //釋放內(nèi)存
void print(int * data,int len)
{
for(int i=0;i<len;i++)
cout<<data[i]<<" ";
cout<<endl;
}
void print(double * data,int len)
{
for(int i=0;i<len;i++)
cout<<data[i]<<" ";
cout<<endl;
}
void zero(int *data,int len)
{
for(int i=0;i<len;i++)
data[i]=0;
}
void zero(double *data,int len)
{
for(int i=0;i<len;i++)
data[i]=0;
}
void rsc(int * input,int * output,int len)
{
int reg[3];
zero(reg,3);
int feedback[3] = {0,0,0};
for(int i=0;i<len;i++)
{
feedback[2] = reg[2] ^ reg[1];
feedback[0] = feedback[2] ^ input[i];
feedback[1] = feedback[0] ^ reg[0];
output[i] = feedback[1] ^ reg[2];
reg[2] = reg[1];
reg[1] = reg[0];
reg[0] = feedback[0];
}
}
void encode(int * input)
{
rx_data = new double[3*block_size];
// print(input,block_size);
// int * y =new int[block_size];
int y[block_size];
zero(y,block_size);
rsc(input,y,block_size);
// print(y,block_size);
// int * inter = new int[block_size];
int inter[block_size];
zero(inter,block_size);
//init();
for(int i=0;i<block_size;i++)
inter[i] = input[intlv_array[i]];
// interleaver(input);
// int *y1 = new int[block_size];
int y1[block_size];
zero(y1,block_size);
rsc(inter,y1,block_size);
print(inter,block_size);
for(i=0;i<block_size;i++)
{
rx_data[3*i] = input[i];
rx_data[3*i+1] = y[i];
rx_data[3*i+2] = y1[i];
}
// print(rx_data,3*block_size);
for(i=0;i<3*block_size;i++)
{
if(rx_data[i]==0)
rx_data[i]=-1;
}
}
void turbo_decode() //控制譯碼的函數(shù)
{
interleaver(rx_s2); //對輸入第二級譯碼器的數(shù)據(jù)進行交織運算
// cout<<"rx_s2:";
// print(rx_s2,block_size);
int i; //用于控制迭代譯碼次數(shù)的循環(huán)變量
for(i=0;i<niter-1;i++) //首先迭代N-1次，在譯碼器之間傳遞外信息
{
log_map_ext(rx_s1,rx_p1,ext2,ext1); //第一級譯碼器譯碼，輸出外信息
interleaver(ext1); //對第一級譯碼器輸出的外信息進行交織，然后輸入到第二級譯碼器
log_map_ext(rx_s2,rx_p2,ext1,ext2); //第二級譯碼器譯碼，輸出外信息
deinterleaver(ext2); //對第二級譯碼器輸出的外信息解交織，然后輸入到第一級譯碼器
}
//最后一次譯碼
log_map_ext(rx_s1,rx_p1,ext2,ext1); //第一級譯碼器譯碼，輸出外信息
interleaver(ext1); //對第一級譯碼器輸出的外信息進行交織，然后輸入到第二級譯碼器
log_map_llr(rx_s2,rx_p2,ext1,ext2); //第二級譯碼器譯碼，輸出對數(shù)似然比
deinterleaver(ext2); //將第二級譯碼器輸出的對數(shù)似然比解交織
/* for(i=0;i<block_size;i++)
{
cout<<ext2[i]<<" ";
}
cout<<endl;*/
decision(ext2); //對第二級譯碼器輸出的對數(shù)似然比進行硬判決，作為最后的譯碼輸出
for (i=0;i<block_size;i++ )
{
de_data[i]=(int)ext2[i];
}
freemem();
}
void decode_init()
{
int i=0,j=0;
rx_s1=new double[block_size];
zero(rx_s1,block_size);
rx_s2=new double[block_size];
zero(rx_s2,block_size);
rx_p1=new double[block_size];
zero(rx_p1,block_size);
rx_p2=new double[block_size];
zero(rx_p2,block_size);
/* for(i=0;i<3*block_size;i++)
{
cout<<rx_data[i]<<" ";
}
cout<<endl;*/
for(i=0;i<3*block_size;i=i+3)
{
rx_s1[j]=rx_data[i];
rx_s2[j]=rx_data[i];
rx_p1[j]=rx_data[i+1];
rx_p2[j]=rx_data[i+2];
j++;
}
//cout<<"rx_s2:"; print(rx_s2,block_size);
/* cout<<"rx_s2:";
print(rx_s1,block_size);
cout<<endl;
cout<<"rx_p1:";
print(rx_p1,block_size);
cout<<endl;
cout<<"rx_p2:";
print(rx_p2,block_size);
cout<<endl;*/
//初始化其它
ext1=new double[block_size];
ext2=new double[block_size];
zero(ext1,block_size);
zero(ext2,block_size);
alpha=new double*[block_size];
beta=new double*[block_size];
for(i=0;i<block_size;i++) //創(chuàng)建alpha,beta矩陣
{
alpha[i]=new double[8];
beta[i]=new double[8];
}
for(i=0;i<block_size;i++)
{
for(j=0;j<8;j++)
{
alpha[i][j]=0;
beta[i][j]=0;
}
}
alpha[0][0]=0; //初始化alpha
for(i=1;i<8;i++)
{
alpha[0][i]=-Infty_1;
}
for(i=0;i<8;i++) //初始化beta
{
beta[block_size-1][i]=-Infty_1;
}
gama=new double*[block_size];
for(i=0;i<block_size;i++)
{
gama[i]=new double[4];//00 01 10 11
}
for(i=0;i<block_size;i++)
{
for(j=0;j<4;j++)
gama[i][j]=0;
}
//Lc=4*pow(10,SNR/10); //Lc=4*(EsN0)
// Lc=4*0.5*pow(10,SNR_db/10);//SNR=(long double)pow(10.0,SNR_db/10.0);
Lc=4*rate*SNR;
// cout<<"snr"<<SNR<<endl;
// cout<<"lc"<<Lc<<endl;
// de_data=new int[block_size];
// int de_data[block_size];
zero(de_data,block_size);
}
int gcd(int a, int b)
{
int v, u, t, q;
u = abs(a);
v = abs(b);
while (v>0)
{
q = u / v;
t = u - v*q;
u = v;
v = t;
}
return(u);
}
void creat_interleaver()
{
intlv_array=new int[block_size]; //交織和解交織數(shù)組初始化
de_intlv_array=new int[block_size];
const int MAX_INTERLEAVER_SIZE = 5114;
const int MIN_INTERLEAVER_SIZE = 40;
int K;
int R;
int C;
int p=0;
int v=0;
int *s;
int *q;
int *r;
int *T;
int **U;
int i, j, qj, temp, row, col, index, count;
int interleaver_size = block_size;
if(interleaver_size > MAX_INTERLEAVER_SIZE)
{
cout<<"td-scdma_turbo_interleaver_sequence: The interleaver size is too large"<<endl;
}
if(interleaver_size < MIN_INTERLEAVER_SIZE)
{
cout<<"td-scdma_turbo_interleaver_sequence: The interleaver size is too small"<<endl;
}
K = interleaver_size;
static int primes[55] = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,211,223,227,229,233,239,241,251,257};
static int roots[55] = {0,0,0,3,2,2,3,2,5,2,3,2,6,3,5,2,2,2,2,7,5,3,2,3,5,2,5,2,6,3,3,2,3,2,2,6,5,2,5,2,2,2,19,5,2,3,2,3,2,6,3,7,7,6,3};
int primes_length = 55;
if ((K>=40) && (K<=159))
{
R = 5;
}
else if ( ((K>=160)&&(K<=200)) || ((K>=481)&&(K<=530)) )
{
R = 10;
}
else {
R = 20;
}
if ((K>=481)&&(K<=530))
{
p = 53;
v = 2;
C = p;
}
else
{
for (i=0; i<primes_length; i++)
{
if ( ( double(primes[i]+1) - double(K)/double(R) ) >= 0.0 )
{
p = primes[i];
v = roots[i];
break;
}
}
if ( ( double(p) - double(K)/double(R) ) >= 0.0 )
{
if ( ( double(p) - 1.0 - double(K)/double(R) ) >= 0.0 )
{
C = p-1;
}
else
{
C = p;
}
}
else
{
C = p+1;
}
}
s = new int[p-1];
s[0] = 1;
for (i=1; i<=(p-2); i++)
{
s[i] = (int) fmod((v * s[i-1]), p);
}
q = new int[R];
q[0] = 1;
for (j=1; j<=(R-1); j++)
{
for (i=0; i<primes_length; i++)
{
qj = primes[i];
if ( (qj>6) && (qj>q[j-1]) )
{
if (gcd((int) qj,(int) (p-1)) == 1)
{
q[j] = qj;
break;
}
}
}
}
static int Pat1[20] = {19,9,14,4,0,2,5,7,12,18,10,8,13,17,3,1,16,6,15,11};
static int Pat2[20] = {19,9,14,4,0,2,5,7,12,18,16,13,17,15,3,1,6,11,8,10};
static int Pat3[10] = {9,8,7,6,5,4,3,2,1,0};
static int Pat4[5] = {4,3,2,1,0};
if (K>=3211)
{
T = Pat1;
}
else if (K>=3161)
{
T = Pat2;
}
else if (K>=2481)
{
T = Pat1;
}
else if (K>=2281)
{
T = Pat2;
}
else if (K>=531)
{
T = Pat1;
}
else if (K>=481)
{
T = Pat3;
}
else if (K>=201)
{
T = Pat1;
}
else if (K>=160)
{
T = Pat3;
}
else
{
T = Pat4;
}
r=new int[R];
for (j=0; j<=(R-1); j++)
{
r[ T[j] ] = q[j];
}
U = new int*[R];
for (i=0;i<R;i++)
{
U[i] = new int[C];
}
if (C==p)
{
for (j=0; j<=(R-1); j++)
{
for (i=0; i<=(p-2); i++)
{
U[j][i] = s[(int) fmod((int) (i*r[j]), (int) (p-1)) ];
}
U[j][p-1] = 0;
}
}
else if (C==(p+1))
{
for (j=0; j<=(R-1); j++)
{
for (i=0; i<=(p-2); i++)
{
U[j][i] = s[(int) fmod((int) (i*r[j]),(int) (p-1)) ];
}
U[j][p-1] = 0;
U[j][p] = p;
}
if (K == (C*R))
{
temp = U[R-1][p];
U[R-1][p] = U[R-1][0];
U[R-1][0] = temp;
}
}
else if (C==(p-1))
{
for (j=0; j<=(R-1); j++)
{
for (i=0; i<=(p-2); i++)
{
U[j][i] = s[(int) fmod((int) (i*r[j]),(int) (p-1)) ] - 1;
}
}
}
count = 0;
for (i=0; i<C; i++)
{
for (j=0; j<R; j++)
{
row = T[j];
col = U[row][i];
index = row * C + col;
if (index < K)
{
intlv_array[count] = index;
count++;
}
}
}
for (i=0;i<K;i++)
{
de_intlv_array[intlv_array[i]] = i;
}
for (i=0;i<R;i++)
{
delete U[i];
}
delete []s;
delete []q;
delete []r;
// delete []T;
delete []U;
}
void interleaver(int *data)
{
int i;
int *temp=new int[block_size];
for(i=0;i<block_size;i++)
{
temp[i]=data[i];
}
for(i=0;i<block_size;i++)
{
data[i]=temp[intlv_array[i]];
}
delete []temp;
}
void interleaver(double *data)
{
int i;
double *temp=new double[block_size];
for(i=0;i<block_size;i++)
{
temp[i]=data[i];
}
for(i=0;i<block_size;i++)
{
data[i]=temp[intlv_array[i]];
}
delete []temp;
}
void deinterleaver(int *data)
{
int i;
int *temp=new int[block_size];
for(i=0;i<block_size;i++)
{
temp[i]=data[i];
}
for(i=0;i<block_size;i++)
{
data[i]=temp[de_intlv_array[i]];
}
delete []temp;
}
void deinterleaver(double *data)
{
int i;
double *temp=new double[block_size];
for(i=0;i<block_size;i++)
{
temp[i]=data[i];
}
for(i=0;i<block_size;i++)
{
data[i]=temp[de_intlv_array[i]];
}
delete []temp;
}
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