Widely Linear Channel Estimation for LD-STBC MB-OFDM UWB Systems

What is it about?

The combination of LD-STBCsand MB-OFDM UWB technologies has been proposed in the literature to improve the error performance and data rate. Recently, it has been shown that the LD codes allow the repetitions of data symbols conjugates. They cause a transformation of the MIMO channel that requires a Widely Linear (WL) filtering. However, proposed LD-STBCMB-OFDM UWB system doesn’t take this issueinto account. In this paper, we propose a WLMMSE channel estimator for LD-STBCMB-OFDM UWB systems. The proposed channel estimator proceeds to WL estimation instead of linear one. Via simulation results, we prove that the LD-STBCs provide significant performance gainfor MB-OFDM UWB system compared to SISO configuration. We show also that the proposed WLMMSE channel estimator outperformsthe LMMSE one. This performance improvement is observed for both proper and improper signal constellations. Additionally, the computational complexity of our proposal is comparable with that of LMMSE estimator.

Featured Image