时变信道下OFDM系统中一种基于修正Kalman滤波的Turbo均衡

在OFDM系统中,由于时变多径信道的存在使子载波间失去了正交性,从而导致子载波间干扰(ICI),降低了系统性能.为了补偿时变信道下OFDM系统中存在的ICI影响,提出了一种基于修正Kalman滤波的Turbo均衡算法:通过Turbo迭代,利用软映射和软解映射算法提供的软值信息,实现模块之间的信息交换;通过修正Kalman预测和滤波,实现信道响应的逐符号更新;通过基于最大化信干噪比缩短窗的ICI抑制,实现信道响应中ICI分量的消除.理论分析和仿真结果表明,所给出的方法能够有效地跟踪信道并抑制ICI影响,即使在快时变信道中也能获得很好的性能.

Turbo Equalization for OFDM with Time-Varying Channels by New Modified Kalman Filter

Time-varying channels lead to the loss of orthogonality among sub-carriers,resulting in inter-carrier interference(ICI) in OFDM systems.To compensate for this ICI,we give a turbo equalization based on new Kalman filter for OFDM with time-varying channels.This algorithm uses soft mapping and soft de-mapping to realize information exchange via turbo iteration,realizes the update of channel response,and mitigates the ICI partly.Theoretical analysis and simulation results indicate that the method in this paper can effectively track the channel and mitigate the ICI.It has good BER performance even the channels are fast time-varying.