Abstract: Superposition Coded Modulation-Orthogonal Frequency Division Multiplexing（SCM-OFDM）systems are prone to the problem of serious interference from multiple-layers and inter-carriers when mobile terminals are in a high speed environment. To alleviate this problem, an interference estimation and cancellation algorithm is proposed for SCM-OFDM systems in high speed channels. In this algorithm, the Intercarrier Interference（ICI） and Multiple-Layer Interference（MLI） can be estimated and cancelled separately based on the soft information fed back from decoders. Simulation results show that the proposed algorithm can improve the performance of SCM-OFDM systems in the high speed movement.

Key words: Orthogonal Frequency Division Multiplex（OFDM）, Superposition Coded Modulation（SCM）, high speed channels

摘要： 针对重叠码调制的正交频分复用（SCM-OFDM）系统在高速移动环境中，将产生复杂的载波间干扰和层间干扰问题，提出了一种用于SCM-OFDM系统在高速信道中的干扰估计和抵消算法。该算法利用译码器反馈的软信息，分别对载波间干扰和层间干扰进行估计和消除。仿真结果表明，提出的算法能够有效地改善SCM-OFDM系统在高速环境下的性能。

关键词: 正交频分复用, 重叠码调制, 高速信道