C. Li, H. J. Yang*, F. Sun, J. M. Cioffi, and L. Yang “Multi-User overhearing for cooperative two-way multi-antenna relays,” IEEE Transactions on Vehicular Technology, vol. 65, no. 5, pp. 3796 - 3802, May 2016.
In this paper, an overhearing protocol is proposed for two-way cooperative multi-antenna relaying systems, where the relays equipped with multiple antennas collaborate to relay signals between the base station (BS) and two user equipments (UEs). In the proposed overhearing protocol, the UE in the uplink transmission phase transmits only in the first time slot, i.e., it remains silent in the second time slot, whereas the previous overhearing protocol assumes the UE transmitting also in the second time slot. Therefore, the proposed overhearing protocol is more power-efficient. The precoding matrix at each cooperative relay is optimized in the sense of minimizing the weighted mean squared error (WMSE). Simulation results show that the proposed scheme shows not only lower MSE but also higher achievable sum-rate than existing cooperative relaying schemes.