Two-Cell Two-Way Relaying with Reduced Interference

The fundamental problem in multi-cell two-way relaying is low uplink achievable rate due to the fact that the uplink signal transmitted by a user is significantly contaminated by the downlink signal transmitted simultaneously by the base station (BS) in the neighboring cell, which has much greater power than the power of the user uplink signal. In this paper, a novel relay precoding optimization scheme is proposed in the two-cell two-way relay channel with only local channel state information in pursuit of reducing the inter-cell interference. The optimization problems for finding the relay precoding coefficients are decoupled at each relay, and can be solved using the parameters which are calculated offline according to the users' locations. Simulation results show that the proposed scheme outperforms the conventional two-way relaying and direct communication without relaying for cell-edge users, owing to reduced inter-cell interference.