Pilot design and algorithm for channel estimation in downlink MIMO-FBMC systems

In this paper, we address the channel estimation in downlink multiple input multiple output with filter bank multicarrier (MIMO-FBMC) systems, which serve different users simultaneously. Since there exists intrinsic imaginary interference in FBMC, the pilot design and algorithm are the key for the low-overhead channel estimation in downlink MIMO-FBMC systems. To tackle this issue, we propose a low-overhead pilot design scheme by utilizing the characteristic of the imaginary interference factor, and subsequently, a channel estimation algorithm based on minimum mean square error (MMSE) criteria is presented. It is shown that, the proposed MMSE algorithm is robust to correlation matrix mismatch, and each user can perform the MMSE estimation independently based on the designed downlink pilots, only by partial priori knowledge of MIMO channels. In comparison with traditional methods, the devised channel estimation scheme can attain desirable results at a lower pilot overhead. The proposed channel estimation scheme has been validated through numerical simulations, with regard to minimum bit error rate and mean square error.