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

Abstract

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. Globecom 2009This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of Mitsubishi Electric Research Laboratories, Inc.; an acknowledgment of the authors and individual contributions to the work; and all applicable portions of the copyright notice. Copying, reproduction, or republishing for any other purpose shall require a license with payment of fee to Mitsubishi Electric Research Laboratories, Inc. All rights reserved. Abstract-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-andforward mechanism, we further propose a minimum meansquare error coupling channel estimator. Also, we investigate the performance of the proposed cross-talk cancellation scheme with both analytical and numerical results.

Maximum likelihood channel estimation for residual self-interference cancellation in full duplex relays

“…Recently, selfinterference cancellation techniques have been developed with great improvement [1], [2]. Among these techniques, the self-interference can be cancelled by estimating the selfinterference channels [3], [4] or be suppressed with null-space method in MIMO [5]. However the estimation error and the trade-off between suppression and user rate [6] still lead to residual self-interference (RSI).…”

Asymptotic analysis of full-duplex bidirectional MIMO link with transmitter noise

“…Herein, we study two different digital self-interference mitigation strategies: time-domain cancellation [2], [5] and spatial-domain suppression [2], [3]. The former simply subtracts the known interference signal before detection and decoding, while the latter applies a linear beamforming filter to receive from directions that are orthogonal to the transceiver's own transmission looping back.…”

Time Domain Loop Interference Channel Estimation and Cancellation for Mobile MIMO Wireless Relays

“…In practice, LI cancellation should be performed in a way that is transparent to the existing wireless standard, thus no explicit reference signals should be inserted. This is achieved in [9] where the authors use the signal transmitted from the RS as an 'equivalent' pilot matrix. The authors implement the system in the Frequency Domain (FD), however, so the delay incurred will be intolerable in many systems.…”