A New Coupling Channel Estimator for Cross-Talk Cancellation at Wireless Relay Stations

In this paper, we are concerned with cross-talk interference from the transmit to the receive antenna of a wireless channel-reuse-relay-station (CRRS) that forwards signals over the same channel as it receives signals. By estimating the coupling channel from the transmit to the receive antenna, the proposed scheme performs cross-talk reconstruction and cancellation at the RS. Different from the conventional coupling channel estimation schemes that require the RS to transmit dedicated pilots, the proposed scheme utilizes the random forwarded signals of the RS as pilots for coupling channel estimation, thus avoiding changing the structure of the RS's transmitted signal. For a general RS with any relay mechanism, we propose a least square coupling channel estimator; for an RS with the decode-and-forward mechanism, we further propose a minimum mean-square error coupling channel estimator. Also, we investigate the performance of the proposed cross-talk cancellation scheme with both analytical and numerical results.