Research Issues, Challenges, and Opportunities of Wireless Power Transfer-Aided Full-Duplex Relay Systems

Zhongxiang Wei,Ahmed Al-Tahmeesschi,Sumei Sun,Yufei Jiang,Xu Zhu,Mingzhu Yue

doi:10.1109/access.2017.2779607

Abstract

We present a comprehensive review for wireless power transfer (WPT)-aided full-duplex (FD) relay systems. Two critical challenges in implementing WPT-aided FD relay systems are presented, that is, pseudo FD realization and high power consumption. Existing time-splitting or power-splitting structure based-WPT-aided FD relay systems can only realize FD operation in one of the time slots or only forward part of the received signal to the destination, belonging to pseudo FD realization. Besides, self-interference is treated as noise and self-interference cancellation (SIC) operation incurs high power consumption at the FD relay node. To this end, a promising solution is outlined to address the two challenges, which realizes consecutive FD realization at all times and forwards all the desired signal to the destination for decoding. Also, active SIC, that is, analog/digital cancellation, is not required by the proposed solution, which effectively reduces the circuit complexity and releases high power consumption at the FD relay node. Specific classifications and performance metrics of WPT-aided FD relay systems are summarized. Some future research is also envisaged for WPT-aided FD systems.

Highlights

Wireless power transfer (WPT)-aided relay communications are appealing in the scenarios where regular battery replacement or recharging is inconvenient or even impossible [1], [2]
A dedicated energy harvesting (EH) time slot is assigned at the downlink in the first time slot, in which the base station (BS) and the relay nodes send signal to the multiple users
The first challenge is the pseudo FD realization. It is because time-slitting structure based WPT-aided FD relay systems adopt HD operation in one of the time slots and FD operation is only realized in the remaining time, while power-slitting structure based FD can not forward all the received signal to the destination

Summary

INTRODUCTION

Wireless power transfer (WPT)-aided relay communications are appealing in the scenarios where regular battery replacement or recharging is inconvenient or even impossible (e.g., in a toxic environment) [1], [2]. As for the power-splitting structure based WPT-aided FD relay systems, the relay splits part of the received signal for EH, and forwards the remnant signal to the destination for decoding [20]. The first challenge is the pseudo FD realization It is because time-slitting structure based WPT-aided FD relay systems adopt HD operation in one of the time slots and FD operation is only realized in the remaining time, while power-slitting structure based FD can not forward all the received signal to the destination. The former deploys the direct-conversion radio architecture to estimate the selfinterference and subtracts it at the relay’s receiver end This kind of AC circuit design does not need additional baseband signal processing at the relay node and consumes less power. CHALLENGES OF WPT-AIDED FD RELAY SYSTEMS we discuss the critical challenges of WPT-aided FD relay systems

PSEUDO FD REALIZATION

HIGH POWER CONSUMPTION

CONCLUSION