Multiuser Scheduling Schemes for Simultaneous Wireless Information and Power Transfer Over Fading Channels

Abstract

Radio frequency energy harvesting presents a viable solution for prolonging the lifetime of wireless communication devices. In this paper, we study downlink multi-user scheduling for a time-slotted system with simultaneous wireless information and power transfer. In particular, in each time slot, a single user is scheduled to receive information, while the remaining users opportunistically harvest the ambient radio frequency energy. We devise novel online scheduling schemes in which the tradeoff between the users' ergodic rates and their average amount of harvested energy can be controlled. In particular, we modify the well-known maximum signal-to-noise ratio (SNR) and maximum normalized-SNR (N-SNR) schedulers by scheduling the user whose SNR/N-SNR has a certain ascending order (selection order) rather than the maximum one. We refer to these new schemes as order-based SNR/N-SNR scheduling and show that the lower the selection order, the higher the average amount of harvested energy in the system at the expense of a reduced ergodic sum rate. The order-based N-SNR scheduling scheme provides proportional fairness among the users in terms of both the ergodic achievable rate and the average harvested energy. Furthermore, we propose an order-based equal throughput (ET) fair scheduler, which schedules the user having the minimum moving average throughput out of the users whose N-SNR orders fall into a given set of allowed orders. We show that this scheme provides the users with proportionally fair average harvested energies. In this context, we also derive feasibility conditions for achieving ET with the orderbased ET scheduler. Using the theory of order statistics, the average per-user harvested energy and ergodic achievable rate of all proposed scheduling schemes are analyzed and obtained in closed form for independent and non-identically distributed Rayleigh, Ricean, Nakagami-m, and Weibull fading channels.Our closed-form analytical results are corroborated by simulations. Index TermsWireless information and power transfer, RF energy harvesting, multi-user scheduling, fairness.

Multihop Capability Analysis in Wireless Information and Power Transfer Multirelay Cooperative Networks

“…Later in [7][8][9], sophisticated architectures for improving the rate-energy region were further proposed. Moreover, multiuser scheduling in SWIPT system was studied for achieving the maximum sum throughput in [10] and tradeoff between the average per user harvested energy and ergodic achievable rate in [11]. Unlike the above works, Zhong et al [12] considered a novel network architecture, where the source is powered by a dedicated power beacon (PB), and gave the average throughput analysis for two different transmission modes, namely, delay tolerant and delay intolerant.…”

“…This scheme does not consider cooperative transmission, which means that the receiver harvests power and decodes the information from the transmitter directly (this assumption is adopted by most of the previous studies [3,[7][8][9][10][11][12][13][14]). Then, the receiver is taken as the transmitter of the next hop to transmit the information and power.…”

Multi‐device selection scheduling in non‐identically distributed fading channels

“…Potential data power (9) In (8), P d (n) can be obtained by subtracting from P T in (6) the training power by the n devices.…”

Physical Layer Security in Cooperative Energy Harvesting Networks With a Friendly Jammer

“…To the best of authors' knowledge, the role of such TSR circuitries in both-relay-and-jammer-aided networks is not conducted by any previous work. Note that, although the impact of light-of-sight (LOS) on the harvested energy loss in the context of energy harvesting has recently emerged as one important topic [6], it is not considered in this paper. With many individual aspects of both security and energy harvesting, we choose not to investigate the LOS factor.…”