Performance of Networks with an Energy Buffer-Aided Source and a Data Buffer-Aided Relay

In this paper, we analyze the performance of a two-hop communication link between an energy-buffer equipped IoT-type self-sustaining source and a destination, aided by a data buffer equipped access point, which serves as a relay. The source harvests RF energy from the ambience and stores it in an energy buffer. Using a discrete-time continuous-state Markov chain model to model the energy buffer, and a discrete-state Markov chain to model the data buffer, we analyze performance of the link. We show how the continuous-state energy buffer and the discrete-state data buffer can both be balanced by suitable choice of the source transmit power, relay target data rate, and relay power. Since feedback of channel estimates and buffer status is not feasible in this scenario, link selection is based solely on energy-buffer status at the source. The derived analytical expressions are validated by Monte Carlo simulations.