非对称Z信道是一种传输单向出错的无记忆信道。针对这种信道,对Turbo码迭代译码的最大后验概率(MAP)译码算法进行了分析和推导,得出了相应的译码算法。在此基础上,对Turbo码性能进行了仿真,对仿真过程中的关键问题作了论述。结果表明,利用此译码算法,Turbo码在Z信道上可以获得很好的误比特率(BER)性能。
The asymmetric Z-channel is a discrete memoryless channel with one of the input symbols transmitted with noise. The maximum a posterior probability (MAP) decoding algorithm was analyzed, and a modified decoding algorithm on the asymmetric Z-channel was deduced. Based on the algorithm, simulations on the performance of turbo codes have been carried out, and the key issues of simulations are discussed. The simulation results show that turbo codes can get excellent bit error rate performance on the asymmetric Z-channel with our proposed decoding algorithm.