Channel estimation and Equalization for time-varying OFDM system using Kaiman filter

摘要

Orthogonal Frequency Division Multiplexing (OFDM) technique has become major multi carrier technique with the advent of wireless and mobile communications. It is known that OFDM is effective over frequency selective fading. However, ICI (inter-carrier interference) destroys the subcarrier orthogonality in time varying channels. The ICI can be mitigated by using different channel estimation schemes at receiver of fast fading systems. Though many channel estimation techniques have already existed, they suffer from complexity in implementation. Efficient channel estimation can be done by assuming channel as a linear state space model i.e., Kaiman filter model. This paper discusses about the Kaiman filter based channel estimation technique that can be implemented with less complexity yet efficient for a time varying channel model. The Equalization is employed using a time-domain filter that maximizes receiver SINR. Also, the proposed technique's efficiency is proved in terms of MSEE, BER in comparison with other techniques.