Dynamic Power Splitting for SWIPT with Nonlinear Energy Harvesting in Ergodic Fading Channel

TL;DR

This paper investigates optimal dynamic power splitting strategies for SWIPT in ergodic fading channels considering realistic nonlinear energy harvesting models, addressing the nonconvex rate-energy tradeoff with solutions for different CSI scenarios.

Contribution

It introduces the first optimal and suboptimal dynamic power splitting schemes for nonlinear EH in SWIPT, considering various CSI conditions and energy maximization.

Findings

Proposed schemes outperform existing methods.

Suboptimal scheme nearly matches optimal performance.

Significant improvements in energy harvesting efficiency.

Abstract

We study the dynamic power splitting for simultaneous wireless information and power transfer (SWIPT) in the ergodic fading channel. Considering the nonlinearity of practical energy harvesting circuits, we adopt the realistic nonlinear energy harvesting (EH) model rather than the idealistic linear EH model. To characterize the optimal rate-energy (RE) tradeoff, we consider the problem of maximizing the R-E region, which is nonconvex. We solve this challenging problem for two different cases of the channel state information (CSI): (i) when the CSI is known only at the receiver (the CSIR case) and (ii) when the CSI is known at both the transmitter and the receiver (the CSI case). For these two cases, we develop the corresponding optimal dynamic power splitting schemes. To address the complexity issue, we also propose the suboptimal schemes with low complexities. Comparing the proposed schemes to the existing schemes, we provide various useful and interesting insights into the dynamic power splitting for the nonlinear EH. Furthermore, we extend the analysis to the scenarios of the partial CSI at the transmitter and the harvested energy maximization. Numerical results demonstrate that the proposed schemes significantly outperform the existing schemes and the proposed suboptimal scheme works very close to the optimal scheme at a much lower complexity.