Relay-Aided Bidirectional Communications Between Devices in a Hybrid User Scenario for IoT

This paper explores a relay aided bidirectional communications scenario between two users embedded with two different technologies. One of these two energy constrained users is a backscatter device and the other is an energy harvesting (EH) device. The relay node controls the communication process between the two users in such a way that it facilitates in both energy and information cooperation and therefore, acts as a global controller for the model under consideration. Under this setting, we aim to maximize the weighted sum-throughput over a joint set of constraints in the time allocation parameter and the energy and information beamforming vectors. Henceforth, we present an optimal solution for the special case of our problem such that the relay node is equipped with a single antenna. In addition, we also present a sub-optimal solution to the generalized case for the multi-antenna relay node. Finally, the numerical simulations demonstrate our system's performance when we vary the key parameters of the simulation setting.