用于盲接收的turbo均衡与迭代信道估计

Turbo Equalization and Iterative Channel Estimation for Blind Receiver

Turbo均衡是一种将信道均衡和差错控制译码联合迭代处理的均衡机制,与传统的均衡器相比,能在更低的信噪比条件下克服严重信道失真导致的符号间干扰(ISI)。该文提出一种用于盲接收的turbo均衡和迭代信道估计方案,不依赖于训练序列或发送符号的先验知识,采用初始盲均衡处理来启动迭代信道估计和turbo均衡。在该方案中,初始盲均衡算法的选择是十分关键的,它需要在恶劣的信道条件为后续迭代处理的启动提供足够的先验信息。该文根据turbo均衡的特点,选择了超指数算法作为初始盲均衡。仿真结果表明,该文提出的用于盲接收的turbo均衡方案是有效的。

A turbo equalizer is able to overcome severe inter-symbol-interferences because it benefits from the channel decoding gain by iteratively performing equalization and channel decoding. This paper proposes a scheme of turbo equalization and iterative channel estimation for blind receiver. The scheme exploits a conventional blind equalizer to bootstrap the iterative process and thus is independent of training sequence and a priori information of the transmitted symbols. In such a scheme, the initial blind equalization algorithm is critical and should be able to provide enough information for the following turbo equalization and channel estimation even when channel distortion is severe. Based on analysis of characteristics of turbo equalization, the super exponential algorithm is chosen as the initial blind equalization. Simulation results illustrating performance of the proposed scheme are also given.