写一段固定路径的LDPC译码C语言代码
时间: 2023-07-10 16:35:46 浏览: 68
这里是一个固定路径的LDPC译码的C语言代码示例:
```
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_N 1024
#define MAX_M 1024
#define MAX_DEGREE 20
typedef struct {
int row;
int col;
} node_t;
typedef struct {
int row;
int degree;
int col[MAX_DEGREE];
} row_info_t;
int H[MAX_N][MAX_M];
int n, m;
row_info_t row_info[MAX_N];
int syndrome[MAX_M];
void init_H(char* filename) {
FILE* fp = fopen(filename, "r");
fscanf(fp, "%d %d", &n, &m);
for (int i = 0; i < n; i++) {
row_info[i].row = i;
row_info[i].degree = 0;
for (int j = 0; j < m; j++) {
int h;
fscanf(fp, "%d", &h);
if (h) {
H[i][row_info[i].degree] = j;
row_info[i].col[row_info[i].degree] = j;
row_info[i].degree++;
}
}
}
fclose(fp);
}
void decode(int max_iter, double* y, int* x) {
double r[MAX_N] = {0};
double q[MAX_N][MAX_DEGREE] = {{0}};
double z[MAX_M] = {0};
int iter = 0;
while (iter < max_iter) {
// Compute syndrome
memset(syndrome, 0, sizeof(syndrome));
for (int i = 0; i < n; i++) {
double s = 0;
for (int j = 0; j < row_info[i].degree; j++) {
s += q[i][j];
}
r[i] = y[i] - s;
for (int j = 0; j < row_info[i].degree; j++) {
q[i][j] = r[i] + q[i][j] - z[row_info[i].col[j]];
}
if (r[i] > 0) {
for (int j = 0; j < row_info[i].degree; j++) {
z[row_info[i].col[j]] += r[i] - q[i][j];
}
}
else {
for (int j = 0; j < row_info[i].degree; j++) {
z[row_info[i].col[j]] -= r[i] + q[i][j];
}
}
syndrome[row_info[i].row] = (r[i] > 0) ? 1 : 0;
}
// Check if the code is decoded
int error_count = 0;
for (int i = 0; i < m; i++) {
error_count += syndrome[i];
}
if (error_count == 0) {
break;
}
iter++;
}
// Copy result to output array
for (int i = 0; i < m; i++) {
x[i] = (syndrome[i] > 0) ? 1 : 0;
}
}
int main(int argc, char** argv) {
if (argc != 3) {
printf("Usage: %s H_file y_file\n", argv[0]);
return 1;
}
char* H_file = argv[1];
char* y_file = argv[2];
double y[MAX_N] = {0};
int x[MAX_M] = {0};
init_H(H_file);
FILE* fp = fopen(y_file, "r");
for (int i = 0; i < n; i++) {
fscanf(fp, "%lf", &y[i]);
}
fclose(fp);
decode(100, y, x);
for (int i = 0; i < m; i++) {
printf("%d ", x[i]);
}
printf("\n");
return 0;
}
```
这个代码实现了一个基于固定路径的LDPC译码算法,它使用了矩阵H来表示LDPC码的校验矩阵,使用了向量y来表示接收到的码字。在译码过程中,它使用了迭代的方式来计算r、q和z,并计算出码字的综合值。最后,它将译码结果保存在输出向量x中。