Voluntary Energy Harvesting Relays and Selection in Cooperative Wireless Networks

Abstract

Abstract-The use of energy harvesting (EH) nodes as cooperative relays is a promising and emerging solution in wireless systems such as wireless sensor networks. It harnesses the spatial diversity of a multi-relay network and addresses the vexing problem of a relay's batteries getting drained in forwarding information to the destination. We consider a cooperative system in which EH nodes volunteer to serve as amplify-and-forward relays whenever they have sufficient energy for transmission. For a general class of stationary and ergodic EH processes, we introduce the notion of energy constrained and energy unconstrained relays and analytically characterize the symbol error rate of the system. Further insight is gained by an asymptotic analysis that considers the cases where the signal-to-noise-ratio or the number of relays is large. Our analysis quantifies how the energy usage at an EH relay and, consequently, its availability for relaying, depends not only on the relay's energy harvesting process, but also on its transmit power setting and the other relays in the system. The optimal static transmit power setting at the EH relays is also determined. Altogether, our results demonstrate how a system that uses EH relays differs in significant ways from one that uses conventional cooperative relays.

Optimal Paring of Spectrum Sensing Duration and Threshold for Energy-Harvesting CRNS

“…We assume that the secondary transmitter always has data to transmit [14]. When the secondary transmitter correctly senses that the spectrum is idle under the hypothesis H0, it can transmit data successfully without any interference.…”

“…Moreover, the issue surrounding sensing configuration has been studied in various environments, such as asynchronous communication mechanism that allows single reader and writer processes to access a shared memory in such a way that interference between concurrent reads and writes is avoided. Asynchronous less communication is used when data is more important than avoiding latency [8]- [10]. We have to consider both the collision constraint and energy causality constraint in their design, to achieving both energy efficiency and spectral efficiency for energy-harvesting systems.…”

Wireless Power Transfer in Two-Way AF Relaying Networks

“…Energy transfer efficiency is subject to channel fading, similar to wireless information signals, and therefore, multi-antenna and cooperative communication techniques can be used to further increase the efficiency of such systems [6], [7]. For example, the authors in [8] studied the performance of energy beamforming in multiple-antennas WPCN.…”

User association for energy harvesting relay stations in cellular networks

“…In [16], the optimal energy usage was discussed for the base stations (BSs) powered by both on-grid energy and renewable energy. A cooperative system with the energy harvesting relays was analyzed in [17]. The authors of [18] studied the resource management problem for a mesh topology network with renewable energy source based on a queueing model, taking into account the relay path selection and the admission control.…”