Citation: Guler, N.; Gunes, A. Optimal Resource Allocation Scheme Based on Time Slot Switching for Point-to-Point SISO SWIPT Systems. Eng. Proc. 2023, 58, 81. https:// doi.org/10.3390/ecsa-10-16247 Academic Editor: Stefano Mariani Published: 15 November 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Proceeding Paper Optimal Resource Allocation Scheme Based on Time Slot Switching for Point-to-Point SISO SWIPT Systems † Nivine Guler 1, * and Ali Gunes 2 1 Department of Informatics Engineering, University of Technology Bahrain, Salmabad 18041, Bahrain 2 Department of Computer Engineering, Istanbul Aydin University, Istanbul 34295, Turkey; aligunes@aydin.edu.tr * Correspondence: n.guler@utb.edu.bh; Tel.: +973-33361859 † Presented at the 10th International Electronic Conference on Sensors and Applications (ECSA-10), 15–30 November 2023; Available online: https://ecsa-10.sciforum.net/. Abstract: This paper presents an optimal resource allocation scheme based on time slot switching (TS) for point-to-point single-input single-output (SISO) simultaneous wireless information and power transfer (SWIPT) systems, aiming to maximize the average achievable rate. The proposed scheme considers the nonlinear energy harvesting (EH) characteristic, and thus, the problem is formulated as a nonconvex optimization problem in the presence of a binary TS ratio. Hence, solving the problem is performed using the time-sharing strong duality theorem and Lagrange dual method. Simulations showed that the proposed scheme improves energy efficiency with respect to different transmission powers by 20%, 10%, and 3% for high-SNR, medium-SNR, and low-SNR regions, respectively. Improvement with respect to average energy efficiency versus other system performance metrics has also been noted for the proposed scheme. Keywords: energy harvesting; information decoding; SWIPT; time slot switching; SNR 1. Introduction Energy shortage is considered as one of the main issues faced by energy-constrained wireless networks [1]; hence, energy shortage directly affects the network lifetime and performance. Energy harvesting (EH) becomes a promising solution for reducing energy consumption and extending the lifetime of energy-constrained wireless networks where nodes harvest energy from the surrounding environment. The simultaneous wireless information and power transfer (SWIPT) is one of the EH technologies, where energy harvesting is performed through the radio frequency (RF) signals since RF signals are able to carry both information and electromagnetic energy simultaneously. Thus, SWIPT is currently an area of high research interests due to its higher efficiency compared to that of information and power transmission with orthogonal resources, i.e., time or frequency channels [2]. Authors of [3,4] present a trade-off between the amount of harvested energy and the achievable rate for the SWIPT systems in the frequency selection channel with additive white Gaussian noise (AWGN). TS and power splitting (PS) SWIPT receivers were first proposed in [5], and since then, the idea of using TS and PS SWIPT receivers has been adopted in the literature. Authors of [6] present multiuser single-input single-output (SISO) orthogonal frequency-division multiplexing (OFDM) system where the TS and PS ratios are optimized to maximize the weighted sum rate of all receivers. Authors of [7] propose an energy efficiency maximization optimization scheme for the multiuser multicarrier energy-constrained amplify-and-forward (AF) multi-relay network. Aiming at minimizing the transmission power, the power allocation problem for the multiuser system is studied, and the optimal PS ratio is obtained in [8]. Power allocation and subcarrier allocation schemes are presented in [9,10] for energy-efficient, large-scale, multiple-antenna SWIPT systems. Most of the proposed SWIPT systems in the literature consider the linear EH Eng. Proc. 2023, 58, 81. https://doi.org/10.3390/ecsa-10-16247 https://www.mdpi.com/journal/engproc