A Hybrid Protocol for SWIPT in Cooperative Networks

Abstract

A promising technology for addressing network lifetime and energy bottlenecks in wireless networks is the Simultaneous Wireless Information and Power Transfer (SWIPT). In this paper, a Hybrid Time switching and Power splitting-based Relaying (HTPR) protocol for SWIPT in an Amplify-and-Forward (AF) network is proposed. The network consists of a source, relay, and destination in which the relay performs Energy Harvesting (EH) from the source signal and uses the harvested energy to transmit the signal to the destination. A direct link exists between the source and destination, and the signals from the source and relay are combined by the Maximum Ratio Combining (MRC) method at the destination. Closed-form expressions for outage probability are derived under delay-limited transmission to determine the achievable throughput at the destination in different transmission schemes. For a constant data rate, HTPR protocol with uniform and optimal EH ratios are considered for throughput maximization. To solve the optimization problem, the convex optimization technique Lagrange multiplier method and Karush-Kuhn-Tucker (KKT) conditions are used. Results show that the HTPR protocol has higher throughput than other SWIPT protocols at relatively high Signal-to-Noise Ratio (SNR).