Accumulate Then Transmit: Multiuser Scheduling in Full-Duplex Wireless-Powered IoT Systems

Abstract

This paper develops and evaluates an accumulatethen-transmit framework for multi-user scheduling in a fullduplex (FD) wireless-powered Internet-of-Things system, consisting of multiple energy harvesting (EH) IoT devices (IoDs) and one FD hybrid access point (HAP). All IoDs have no embedded energy supply and thus need to perform EH before transmitting their data to the HAP. Thanks to its FD capability, the HAP can simultaneously receive data uplink and broadcast energybearing signals downlink to charge IoDs. The instantaneous channel information is assumed unavailable throughout this paper. To maximize the system average throughput, we design a new throughput-oriented scheduling scheme, in which a single IoD with the maximum weighted residual energy is selected to transmit information to the HAP, while the other IoDs harvest and accumulate energy from the signals broadcast by the HAP. However, similar to most of the existing throughput-oriented schemes, the proposed throughout-oriented scheme also leads to unfair inter-user throughput because IoDs with better channel performance will be granted more transmission opportunities. To strike a balance between the system throughput and user fairness, we then propose a fairness-oriented scheduling scheme based on the normalized accumulated energy. To evaluate the system performance, we model the dynamic charging/discharging processes of each IoD as a finite-state Markov Chain. Analytical expressions of the system outage probability and average throughput are derived over Rician fading channels for both proposed schemes. Simulation results validate the performance analysis and demonstrate the performance superiority of both proposed schemes over the existing schemes.

Secure Green-Oriented Multiuser Scheduling for Wireless-Powered Internet of Things

“…Remarkably, in an effort to reduce the complexity and the costs of resource-constricted wirelesspowered IoT, the multiuser scheduling has drawn wide attention due to the significant potential performance improvement [14][15][16][17][18][19]. Particularly, the authors in [14] explore the largest energy efficiency for multiuser WPCN by joint power control and time allocation while taking account of the initial battery energy level of all the users.…”

“…Afterwards, the authors in [18] concentrate on an MIMO-WPCN, in which a dedicated multiantenna PB transfers RF energy to some starve users, and then these users send required information to the destination. And, last but not the least, [19] focuses on the cumulative transmission framework of multiuser scheduling in full-duplex wireless-powered IoT system and designs a novel throughput-oriented scheduling strategy, which models the dynamic charging and discharging procedures for all the devices in IoT as a finite-state Markov chain.…”

Joint Transceiver Optimization for Multiuser Multi-Antenna Relay Systems With Energy Harvesting

“…MIMO transceiver can not only improve the spectral efficiency by the spatial multiplexing gain but also harvest more energy from the received RF signal via the multiple antennas [6]- [12]. Therefore, the scheme of combining SWIPT and MIMO has been widely investigated to improve the performance of wireless network [13]- [19].…”

Throughput Maximization for Wireless Powered Multimedia Communication Systems Under Statistical Latency Constraint

“…The representative studies based on hybrid mode includes [20]- [23]. In [21], the sum throughput and max-min throughput of a typical wireless powered communication network were studied based on the proposed harvest-then-transmit policy.…”

“…Besides, the maximum downlink throughput was ascertained through optimizing the time allocation and power splitting ratio. In [23], an accumulate-then-transmit framework was built up in a full-duplex (FD) wireless-powered Internet-of-Things system. Also, a fairness-oriented scheduling scheme was studied to guarantee enough opportunity to forward data for all the users.…”