卷积编码及维特比译码

# here put the import lib
import numpy as np

# (2,1,6)卷积码
# 卷积编码
def encode_conv(x):
    # 存储编码信息
    y = []
    # 两个寄存器u_1 u_2初始化为0
    reg = np.zeros((6, ), dtype = np.uint8)
    for j in x:
        c_1 = j ^ reg[0] ^ reg[1] ^ reg[2] ^ reg[5]
        c_2 = j ^ reg[1] ^ reg[2] ^ reg[4] ^ reg[5]
        y.append(c_1)
        y.append(c_2)
        # 更新寄存器
        reg = np.hstack((j, reg[0: -1]))

    print(x,"编码为：",y)
    return y
# 测试代码
if __name__ == '__main__':
    encode_conv([1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1])

# here put the import lib
import numpy as np

def EnCodeOut(state, inBit):
    g1Out = [0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0]
    g2Out = [0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0]

    '''
    #lit = [0, 1, 2,  5]
    lit = [1, 2, 4, 5]
    r = []
    for  i in range(64):
        tmp = 0
        for j in lit:
            tmp^= (i >> j) & 0x1
        r.append(tmp)
    print(r)
    '''
    return g1Out[state]^inBit, g2Out[state]^inBit

# (2,1,6)卷积译码
regBit = 6
stateNum = (1 << regBit)
def Decode(inData):
    t = len(inData) >> 1
    score = np.zeros((stateNum, ), dtype=np.uint32)
    valid = np.ones((stateNum, ), dtype=np.uint8)
    path = np.zeros((t, stateNum), dtype=np.uint8)

    for i in range(t):        # 遍历输入数据的时刻
        tmp1 = np.ones((stateNum, ), dtype=np.uint32) * 10000
        tmp2 = np.zeros((stateNum, ), dtype=np.uint8)
        for j in range(stateNum):   # 遍历各个状态
            if valid[j] ==  False:
                continue

            # 输入bit 0
            g1, g2 = EnCodeOut(j, 0)
            tmpIdx = (i << 1)
            tmpState = (j << 1) & 0x3E
            dis = (inData[tmpIdx] ^ g1) + (inData[tmpIdx + 1] ^ g2)
            if dis < tmp1[tmpState]:
                tmp1[tmpState] = score[j] + dis
                tmp2[tmpState] = True
                path[i][tmpState] = j

            # 输入bit 1
            g1, g2 = EnCodeOut(j, 1)
            tmpIdx = (i << 1)
            tmpState = ((j << 1) & 0x3F) | 0x1
            dis = (inData[tmpIdx] ^ g1) + (inData[tmpIdx + 1] ^ g2)
            if dis < tmp1[tmpState]:
                tmp1[tmpState] = score[j] + dis
                tmp2[tmpState] = True
                path[i][tmpState] = j + 0x80

        score = tmp1
        valid = tmp2

    tmp = np.argmin(score)
    if score[tmp]:
        print("decode failed", score)
    else:
        inBit = []
        for i in range(t):
            tmpIdx = t - i - 1
            inBit.append((path[tmpIdx][tmp] >> 7) & 0x1)
            tmp = path[tmpIdx][tmp] & 0x3F
        print(list(reversed(inBit)))

if __name__ == '__main__':
    Decode([1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1])