Optimal time switching-based policies for efficient transmit power in wireless energy harvesting small cell cognitive relaying networks

Abstract

In this paper, we consider a half-duplex decode-and-forward small cell cognitive relay network, in which the source and the relay node are allocated with spectrum shared by the macro cell primary transmitter (MPT). In order to develop a practical design, we propose two time switching-based policies to optimize the maximum transmit power at source and relay so-called Optimal Time for Transmit Power at Source and Optimal Time for Transmit Power at Relay related to wireless energy harvesting for the considered network, thanks to the advantages of MPT. Additionally, we provide closed-form expressions for outage probability for the proposed policies. Furthermore, to achieve more genuine understandings of the successful data transmission of the small cells, we also consider the delay-constraint throughput, the rate-energy trade-off and the average energy efficiency by giving numerical and simulation results.