Throughput Maximization for Two-Way Buffer-Aided and Energy-Harvesting Enabled Multi-Relay Networks

Fanzi Zeng,Jing Bai,Hongbo Jiang,Vincent Havyarimana,Jingru Sun,Xiang Xiao,Zhu Xiao

doi:10.1109/access.2019.2950070

Abstract

For years, relay communications have been witnessed to extend the network coverage and improve the throughput and reliability of wireless systems. In this paper, we focus on throughput maximization for the two-way buffer-aided relay network with finite data buffers and limited energy battery, wherein relays have no fixed power supply and they replenish energy from the Radio Frequency (RF) signal radiated by source nodes. Specifically, by jointing the time switching and energy splitting for RF energy harvesting, we introduce a three time-subslot transmission model to balance the energy storage and the energy consumption for communication. On top of this transmission model, we formulate an optimization problem for throughput maximization of relay network. We purposely convert the non-convex optimization problem into a convex one by carefully decoupling and relaxing. Further, we theoretically derive the maximum throughput and apply an iterative algorithm to achieve the suboptimal solution based on relay selection and power allocation. In addition to solving the no-delay limited throughput maximization problem, we put forward the solution of the delay limited transmission in the two-way buffer-aided multi-relay networks. Extensive simulations have been conducted to demonstrate that our proposed strategy is able to significantly improve the sum-throughput under transmission energy and delay constraints.

Highlights

The emerging relay communication technology aims at improving the system capacity, resisting channel fading and extending the communication coverage of the wireless network [1], [2]
In order to effectively realize time switching and energy splitting, and balance the energy storage and the energy consumption, we propose a three time-subslot transmission model for two-way buffer-aided and energy-harvesting enabled relay networks in the absence of a direct link between source and destination
DUAL OPTIMIZATION PROBLEM FOR RELAY SELECTION AND POWER ALLOCATION WITH FINITE BUFFERS we strive to maximize the sum-throughput of the multi-relay network by formulating a dual optimization problem based on relay selection and power allocation, and in the meantime preventing the overflowing of energy in the battery and data in buffers

Summary

INTRODUCTION

The emerging relay communication technology aims at improving the system capacity, resisting channel fading and extending the communication coverage of the wireless network [1], [2]. F. Zeng et al.: Throughput Maximization for Two-Way Buffer-Aided and EH Enabled Multi-Relay Networks channel state condition is good; on the other hand, it adopts energy harvesting (EH) technology such as to enable simultaneous power and wireless information transmitting [9], [16]. In order to effectively realize time switching and energy splitting, and balance the energy storage and the energy consumption, we propose a three time-subslot transmission model (detailed in Section III-B) for two-way buffer-aided and energy-harvesting enabled relay networks in the absence of a direct link between source and destination. In two-way buffer-aided relay networks, data transmission between source and destination is achieved through various relay selection schemes which can attain higher diversity gain [11]. If the links between S1-R and R-S2 are not good enough for transmitting the pilot signal, the corresponding relay is not considered for relay selection

TRANSMISSION MODEL

CONVEXIFICATION FOR DUAL

SOLUTION

SIMULATION RESULTS

CONCLUSIONS