Opportunistic scheduling in a bidirectional communication link with relaying

In this paper we study transmission scheduling in a bidirectional communication link, where two end nodes are communicating with each other through a relay node. Each of the two end nodes injects data into a separate buffer at the relay node, which can either forward the data from one end node to the other at a given time (referred to as one-way relay), or simultaneously forwarding the data to both the end nodes by using network coding (referred to as two-way relay). An optimization problem is formulated to find the optimum scheduling in order to maximize the total transmission throughput in both communication directions, and a heuristic scheduling scheme is proposed to opportunistically take advantages of both the channel conditions between the two end nodes and the one-way and two-way relays. Numerical results show that the proposed scheme achieves high and close-to-optimum throughput.