Age of Information in Decode-and-Forward Aided Wireless Powered Two-Hop Sensor Network

Abstract

In order to meet timeliness requirements arising from sensing applications, age of information (AoI) was proposed to characterise the freshness of the received updates. In this paper, we study the average AoI for a two-hop network, in which a relay wirelessly powered by a hybrid-access point (H-AP) receives environmental monitoring information update from a sensor and forwards it to the H-AP. We optimise the transmit power of the relay for the sake of minimising the average AoI in the whole wireless powered relay aided communication nework (WPRCN). The wireless powered relay adopts a decode-and-forward strategy by considering the energy causality. Our simulation results demonstrate the impact of the relay's transmit power on the average AoI, while the information freshness of the WPRCN is optimised by our power allocation scheme at the relay.