Scheduling schemes for two-user two-way wireless relay networks

Abstract

In this paper, we study scheduling schemes for a two-user two-way relaying system. Two transmission modes are considered, i.e., point-to-point direct transmission and two-way amplify-and-forward (AF) relaying. An optimal scheduling method that opportunistically selects the best transmission mode for each user with instantaneous channel state information (CSI) is proposed to minimize the sum bit-error-rate (BER). However, for optimal scheduling, the scheduler requires the knowledge of all the channels. To reduce the feedback information of CSI, we also propose a suboptimal scheduling scheme that only the CSI of the two direct links is explored to select the transmission mode. Simulation results show that both the optimal and suboptimal schemes outperform the fixed direct transmission and fixed two-way relayed transmission, and the performance gap between the optimal and suboptimal scheduling scheme is small. These results show that the suboptimal scheduling scheme provides a good trade-off between implementation complexity and system performance.