Research on coded modulation for non-Gaussian noise channel

研究了非高斯信道的编码调制技术。编码调制通过同时考虑纠错编码和调制来提供可靠的传输。编码调制包括格状编码和多电平编码，对于格状编码，通过估计Bhattacharyya界所限定的成对误码率，得到了误码率的上界公式。该公式用误差状态转移图的回路传递函数表示。对于具有脉冲噪声的基带或通带传输，基于该公式搜索最优编码，并通过计算机仿真验证最优编码的有效性；对于多级编码，我们推导出任意分配各级纠错能力时的误码率的近似公式。通过对基带和通带传输的计算机仿真，验证了该公式的有效性，并研究了编码调制在衰落信道中的应用。在接收机中经过自动增益控制器后，具有高斯噪声的衰落信道等价于没有衰落的非高斯信道。从这个角度出发，我们推导出了瑞利衰落信道下的最优多电平编码。

We studied coded modulation techniques for non-Gaussian channel. The coded modulation gives a reliable transmission by taking an error correcting coding and a modulation into account, simultaneously. The coded modulation includes the trellis coding and the multi-level coding.For the trellis coding, we derived an upper bound formula of bit error rate by the evaluation of pair-wise error rate bounded by the Bhattacharyya bound. The formula is represented by a loop transfer function of an error state transition diagram. For a baseband or a passband transmission with an impulsive noise, we searched the optimum coding based on the formula and verified the usefulness of the optimum coding by a computer simulation.For the multi-level coding, we derived an approximate formula of the bit error rate for an arbitrary assignment of error correcting capability to each level. The validity of the formula is verified by a computer simulation for a baseband or a passband transmission.We also studied the application of the coded modulation for a fading channel. A fading channel with a Gaussian noise is equivalent to a non-Gaussian channel without fading after an automatic gain controller in a receiver. From this view point, we derived an optimum multi-level coding for a Rayleigh fading channel.