卷积码维特比译码c语言实现

卷积码是一种线性分组码，它通过将信息信号进行分组并添加冗余校验位来实现信息的可靠传输。维特比译码（Viterbi decoding）是一种常用的卷积码译码方法，它可以找到最可能的输出序列，从而恢复出原始信息信号。

以下是一个简单的C语言实现：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_N 256
#define H 8
#define W 8

int max(int a, int b) {
    return a > b ? a : b;
}

void viterbi(int *table, int *Htable, int *Wtable, int *state, int *symbol, int *output, int *max_len, int *n) {
    int i, j, k, l, m, n0, n1, n2, n3;
    int max_prob = -1;
    int max_state = 0;
    int max_symbol = 0;

    for (i = 0; i < *n; i++) {
        n0 = n1 = n2 = n3 = 0;
        for (j = 0; j < H; j++) {
            for (k = 0; k < W; k++) {
                if (state[j * W + k] == i) {
                    for (l = 0; l < Htable[j]; l++) {
                        for (m = 0; m < Wtable[k]; m++) {
                            if (symbol[l * W + m] == symbol[j * W + k]) {
                                n0++;
                            } else if (symbol[l * W + m] != 0) {
                                n1++;
                            }
                        }
                    }
                }
            }
        }
        for (j = 0; j < H; j++) {
            for (k = 0; k < W; k++) {
                if (state[j * W + k] == i) {
                    for (l = 0; l < Htable[j]; l++) {
                        for (m = 0; m < Wtable[k]; m++) {
                            if (symbol[l * W + m] == symbol[j * W + k]) {
                                n2++;                            } else if (symbol[l * W + m] != 0) {
                                n3++;
                            }
                        }
                    }
                }
            }
        }
        *max_len = max(max_len, n0);
        *max_len = max(max_len, n1);
        *max_len = max(max_len, n2);
        *max_len = max(max_len, n3);

        if (*max_len > max_prob) {
            max_prob = *max_len;
            max_state = i;
            max_symbol = symbol[i];
        }
    }

    output = max_symbol;
    for (i = 1; i < *n; i++) {
        if (state[max_state * W + output[i - 1]] == 0) {
            output[i] = max_state;
        } else {
            output[i] = state[max_state * W + output[i - 1]];
        }
    }
}

int main() {
    int table[MAX_N][MAX_N], Htable[MAX_N], Wtable[MAX_N];
    int state[MAX_N * H][MAX_N * W];
    int symbol[MAX_N * H][MAX_N * W];
    int output[MAX_N];
    int max_len, n;

    // 初始化参数，例如：
    // 生成卷积码的哈夫曼树，填充Htable和Wtable
    // 根据输入数据生成状态矩阵和符号矩阵

    viterbi(table, Htable, Wtable, state, symbol, output, &max_len, &n);

    printf("解码结果：");
    for (int i = 0; i < n; i++) {
        printf("%d ", output[i]);
    }
    printf("
");

    return 0;
}