Multi-pair and multi-way communications using energy harvesting nodes

In this paper, we consider multi-directional information flow in networks with energy harvesting nodes and intermittent data arrivals at the source nodes. The sum throughput optimization problem is studied in models where an intermediate energy harvesting relay facilitates the multi-directional information exchange in the network. In particular, we consider the multi-way relay channel as well as its special case with two-user clusters, i.e., the multi-pair bidirectional relay channel, with a decode-and-forward relay. A new ingredient that is introduced in this study is the finite size data buffers at each node in addition to the finite size energy storage units (batteries). We observe that the optimal transmission policies can be found by solving the underlying convex optimization problem. We present numerical results for the multi-way and multi-pair setups to demonstrate the throughput performance of the optimal policies and the impact of the finite buffers.