Secrecy Throughput Optimization for the WPCNs With Non-Linear EH Model

Abstract

This paper investigates secure communication from a wireless-powered transmitter to a desired receiver with multiple eavesdroppers in the wireless powered communication networks (WPCNs). Considering the non-linear energy harvesting (EH) model, we propose a secure two-phase communication protocol with the help of a hybrid base station (HBS). First, in the power transfer (PT) phase, the HBS transfers wireless power to the transmitter. Then in the subsequent secure information transmission (SIT) phase, the transmitter sends the secret information using the energy harvested in the PT, under the protection of artificial noise (AN) generated by the HBS. First, based on this communication protocol, we maximize the secrecy throughput with perfect channel information state (CSI) under the transmit power constraint at the HBS. The secrecy throughput maximization (STM) problem is non-convex, and hence we reformulate it by exploiting the primal decomposition method (PDM) to obtain tractable forms. The PDM-based transmit scheme (PDM-TS) is proposed for the STM. In addition, considering the imperfect CSI of wiretap channel, we further design the robust transmit scheme for the worst-case secrecy throughput maximization (wSTM) problem. Since the wSTM shows high non-convexity, we extend the PDM by combining it with the Sprocedure, and the PDM-based robust transmit scheme (PDM-RTS) is proposed for the wSTM. Finally, the numerical simulations are provided to show the effectiveness of the proposed transmit schemes.INDEX TERMS Wireless powered communication networks (WPCNs), non-linear energy harvesting (EH) model, physical layer security (PLS), secrecy throughput, robust beamforming.

Security Performance Analysis for Best Relay Selection in Energy-Harvesting Cooperative Communication Networks

“…However, it will be more valuable and practical to investigate the energy accumulation for the unselected relays in the next T duration [26], [34], which is a novel research direction in the future. Besides, it is also a noteworthy point to extend our work to the nonlinear EH model [35]- [38].…”

“…Although replacing or recharging batteries of relay nodes can avoid energy harvesting, it incurs a high cost and cannot be convenient or even hazardous, such as in toxic environments. Therefore, researchers begin to pay more attention on combining the energy harvesting and cooperation communication to prolong the lifetime of wireless networks and solve the scarcity of energy resources [25]- [38]. Literature [27] investigated the secrecy performance of a two-hop communication between a source and a destination using destination-assisted jamming, for the reason that the source used an AF wireless energyharvesting untrusted relay to forward the confidential information to the legitimate destination.…”

“…Moreover, [34] investigated the AF and compress-and-forward (CF) relay networks with energy-harvesting untrusted relay nodes, and derived the achievable secrecy rate for two scenarios. To be more practical, [35]- [38] extended the researches to nonlinear EH model, where [35] considered the wirelessly powered two-way communication, and [36] analyzed the performance of wireless powered AF relaying over Nakagamim fading channels. Besides, [37] designed the SWIPT protocol for massive multi-input multi-output (mMIMO) system in the beam-domain (BD), and [38] proposed a secure two-phase communication protocol with the help of a hybrid base station (HBS) in the wireless powered communication networks (WPCNs) employing the nonlinear EH model.…”

“…To be more practical, [35]- [38] extended the researches to nonlinear EH model, where [35] considered the wirelessly powered two-way communication, and [36] analyzed the performance of wireless powered AF relaying over Nakagamim fading channels. Besides, [37] designed the SWIPT protocol for massive multi-input multi-output (mMIMO) system in the beam-domain (BD), and [38] proposed a secure two-phase communication protocol with the help of a hybrid base station (HBS) in the wireless powered communication networks (WPCNs) employing the nonlinear EH model. Motivated by the above research, we explore physical layer security for an EH cooperative communication network consisting of a source, a destination, and multiple decodeand-forward (DF) relays, which are capable of collecting the energy from RF signal of the source.…”

Performance Analysis of Energy Beamforming WPCN Links With Channel Estimation Errors

“…Although imperfect CSI for WPCNs is studied in several studies [23]- [32], these works focus on specific application scenarios and associated optimizations. For example, in [23] the EH process is optimized by considering beamforming design, power allocation, antenna selection and time division based on imperfect CSI.…”