Design and Analysis of UAV-Assisted Relaying With Simultaneous Wireless Information and Power Transfer

Abstract

We consider a two-phase decode-and-forward (DF) relay network assisted by an unmanned aerial vehicle (UAV), where the UAV performs energy harvesting and information decoding simultaneously with a power splitting (PS) receiver structure. For the network, we optimize the PS and time allocation (TA) factors to minimize the outage probability in transferring the data from a source to a destination suffering from blockages in the direct link. The optimal solution is found in two steps, optimization of the PS factor for given TA and then optimization of the TA factor using the conditionally optimized PS factor given in a closed-form. To reduce the complexity of the optimal method, we next propose a suboptimal method using a fixed TA determined by the transmission rate only and a fixed PS ffactor given by a function of the average power of the UAV-to-destination channel. The outage probability of the proposed method is analyzed in a generalized UAV channel model including path-loss, shadowing, and Nakagami-m fading, which is shown to agree with the simulation results and is close to the optimal performance. In addition, the optimal UAV position is investigated in various channel environments, which reveals that the optimal altitude depends on the deployment scenarios and the optimal ground position is the center-point between the source and destination in general. INDEX TERMS Decode-and-forward, energy harvesting, lognormal shadowing, Nakagami-m fading, simultaneous wireless information and power transfer, unmanned aerial vehicles.

System Performance Analysis for an Energy Harvesting IoT System Using a DF/AF UAV-Enabled Relay with Downlink NOMA under Nakagami-m Fading

“…Later, RF EH technology was introduced to alleviate the energy consumption problem for UAV equipment [32][33][34]. For example, Yang et al studied the performance of UR networks in urban environments.…”

“…In contrast, Kim et al considered a DF UR network in which the UR performs EH and information decoding simultaneously with a PS protocol, and they adapted the PS ratio to minimize the OP for transferring data from the source to the destination. To evaluate the performance of this system, the OP with the proposed APS ratio was analyzed under a generalized UR channel model with Nakagami-m fading [34]. However, this work focused on a simplified system (i.e., a source, a UR and a destination).…”

Joint Gateway Selection and Resource Allocation for Cross-Tier Communication in Space-Air-Ground Integrated IoT Networks

“…UAV-assisted relaying can provide effective wireless connection without infrastructure and promote the communication quality by enabling transmission between two nodes in the same or different networks [7]. Compared with ground communications, UAV-relaying systems are able to offer more scalable deployment, more elastic configuration, and wider coverage.…”

Outage Performance of Multi-Antenna Mobile UAV-Assisted NOMA Relay Systems Over Nakagami-m Fading Channels

“…Additionally, optimizing the trajectory and transmission power is applied to minimize the outage probability (OP) of the UAV-assisted relay systems [5]. Considering the case that the UAV is able to perform energy harvesting, the authors in [7] derived the approximate performance of a two-phase UAV assisted DF relay network including path-loss, shadowing, and Nakagami-m fading. However, the drawback of [7] is that the communication of only one source−destination pair with stationary UAV was considered.…”