Energy-Efficient Resource Allocation in SWIPT Enabled NOMA Systems

Abstract

In this paper, we investigate joint power allocation and time switching (TS) control for energy efficiency (EE) optimization in a TS-based simultaneous wireless information and power transfer (SWIPT) non-orthogonal multiple access (NOMA) system. Our aim is to optimize the EE of the system whilst satisfying the constraints on maximum transmit power, minimum data rate and minimum harvested energy per-terminal. The considered EE optimization problem is formulated and then transformed according to the duality of broadcast channels (BC) and multiple access channels (MAC). The corresponding non-linear and non-convex optimization problem, involving joint optimization of power allocation and time switching factor, is difficult to solve directly. In order to tackle this problem, we develop a dual-layer algorithm where a convex programmingbased Dinkelbach's method is proposed to optimize the power allocation in the inner-layer and an efficient search method is then applied to optimize the TS factor in the outer-layer. Numerical results validate the theoretical findings and demonstrate that significant performance gain over orthogonal multiple access (OMA) scheme in terms of EE can be achieved by the proposed algorithm in a SWIPT-enabled NOMA system.

A closed-form solution for energy-efficiency optimization in multi-user downlink NOMA

“…B. Ratio between the sum rate and overall power A popular energy-efficiency metric is defined as the ratio between the sum rate and the overall power consumption [7], [12], [13], [15] measured in bits per Joule of consumed energy…”

“…Although our closed-form solution solves a different (more general) problem, it can also be exploited for the same purpose. Using fractional programming [7], [15] and our closed-form solution in Theorem 1, simplifies the optimization of (10) to finding the fixed point of the following function…”

“…In the last couple of years, resource allocation problems for NOMAbased systems have been widely studied in the literature from an energy-efficient perspective. Both uplink [6] and downlink [7], [8] scenarios have been studied given the recent advances in user equipment making possible the implementation of successive interference cancellation (SIC) in practice [9], [10].…”

Near-optimal Detector for SWIPT-enabled Differential DF Relay Networks with SER Analysis

“…It has also become a new source for energy harvesting (EH) in the wireless power transfer (WPT) process [1]. In recent years, simultaneous wireless information and power transfer (SWIPT) has emerged as a promising technology to use the RF signal for WIT and WPT at the same time [2]. SWIPT is an essential technology for various wireless systems to support different applications (see [3] and references therein), for example, for 5G communications to support the Internet of Things (IoT) applications [4].…”

SER Analysis for SWIPT-Enabled Differential Decode-and-Forward Relay Networks

“…It has also become a new source for energy harvesting (EH) in the wireless power transfer (WPT) process [1]. In recent years, simultaneous wireless information and power transfer (SWIPT) has emerged as a promising technology to use the RF signal for WIT and WPT at the same time [2]. SWIPT is an essential technology for various wireless systems to support different applications (see [3], [4] and references therein), for example, for 5G communications to support the Internet of Things (IoT) applications [5].…”