Overhearing-Based Co-Operation for Two-Cell Network with Asymmetric Uplink-Downlink Traffics

In this paper, a new transmission protocol is proposed for a two-cell network, where each cell, respectively, has one-uplink and one-downlink data traffic requirement. By designing bidirectional relaying protocol, which admits the idle nodes to overhear the interference sent by the other nodes, the spectral efficiency can be greatly improved. The proposed overhearing transmission protocol provides a new principle that converts the overheard interference from the negative role to the positive contribution for the desired signal to interference plus noise ratio (SINR) enhancement via various transmit and receive schemes.} In order to enhance the quality of the desirable link, an adaptive receiver consisting of both the minimum mean squared error (MMSE) and MMSE successive interference cancelation (SIC) techniques is proposed. Based on the proposed transmission structure, the precoding is further optimized for the multiantenna relay to maximize the weighted sum-rate of all data traffics with the limited power constraint. At last, simulations verify the gains obtained from the proposed protocol and the optimized relaying precoder.