Multi-Tap Channel Estimation for Preamble-Based FBMC/OQAM Systems

Abstract

The intrinsic imaginary inter-carrier/inter-symbol interference in filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) systems makes accurate channel estimation remain an open issue, which motivates our work in this paper. In order to improve the channel estimation performance for preamble-based FBMC/OQAM systems, a recursive least squares (RLS)-based multi-tap channel estimation (RLS-MTCE) scheme that can effectively reduce the influence of noise is proposed by adopting the widely used signal model of the analysis filter bank (AFB) output. On the other hand, by utilizing the new-built signal model of the AFB output, the authors develop least squares (LS)-based and minimum mean square error (MMSE)-based multi-tap channel estimation schemes, denoted by LS-MTCE and MMSE-MTCE, respectively, to accurately exploit the interference to improve the channel estimation performance. The complexity and performance analysis results show that, compared with the existing schemes, the proposed RLS-MTCE, LS-MTCE and MMSE-MTCE counterparts generally achieve a lower estimation error at the cost of an acceptable increase in computational complexity. INDEX TERMS Channel estimation, FBMC/OQAM, least squares (LS), minimum mean square error (MMSE), multi-tap.