A time domain channel estimation scheme for equalize-and-forward relay-assisted systems

In this paper we propose a scheme with a dedicated relay node for an OFDM-based system. We consider an antenna array at the base station and a single antenna at both the user terminal and the relay node. The relay-assisted protocol considered is equalize-and-forward. The proposed scheme requires the computation of parameters which depend on unknown variables at the destination and we show that under some assumptions the scheme is suitable to provide all those requirements. Also, we show that since the pilots at the relay node are properly designed the TD-MMSE estimator can still provide the required channel estimate. The system performance is evaluated by considering a typical pedestrian scenario based on WiMAX specification. The results show that the degradation in the estimator performance is negligible. ©2010 IEEE.European project Enhanced Wireless Communication Systems Employing Cooperative Diversity – CODIVFP7/ICT/2007/215477Portuguese Cooperative and Antenna Diversity for Broadband Wireless Networks – CADWINPTDC/EEA–TEL/099241/2008Portuguese Foundation for Science and Technology (FCT