Resource Allocation Techniques for Wireless Powered Communication Networks With Energy Storage Constraint

Abstract

This paper studies multi-user wireless powered communication networks, where energy constrained users charge their energy storages by scavenging energy of the radio frequency signals radiated from a hybrid access point (H-AP). The energy is then utilized for the users' uplink information transmission to the H-AP in time division multiple access mode. In this system, we aim to maximize the uplink sum rate performance by jointly optimizing energy and time resource allocation for multiple users in both infinite capacity and finite capacity energy storage cases. First, when the users are equipped with the infinite capacity energy storages, we derive the optimal downlink energy transmission policy at the H-AP. Based on this result, analytical resource allocation solutions are obtained. Next, we propose the optimal energy and time allocation algorithm for the case where each user has finite capacity energy storage. Simulation results confirm that the proposed algorithms offer about 30 % average sum rate performance gain over conventional schemes.

Energy Efficiency Optimization For Wireless Powered Sensor Networks With Nonorthogonal Multiple Access

“…In [7], the well-known "harvest-then-transmit" protocol was proposed, where the time allocated to the hybrid access point (H-AP) for downlink WET and the time and transmit power allocated to the sensors for uplink WIT were jointly optimized for system throughput maximization. Since then, related works have been extensively done in the context of WPSNs with relays [8], [9], full-duplex radio [10], [11], cognitive radio [12]- [15], MIMO [16]- [18] and nonorthogonal multiple access (NOMA) schemes [19]- [21]. However, the above works only focus on the spectrum efficiency of WPSNs, which may lead a great dissipation of energy during the downlink WET.…”

Throughput maximization in wireless powered communication networks with minimum node throughput requirement

“…In (29), for the star-topology WPCN using the HTT transmission way, we have studied the transmission completion time (TCT) minimization problem where each node N i needs to transmit b i bits to H-AP by using the minimal total amount of time and presented an algorithm for finding the optimal time allocations of WET and WITs to achieve the minimum TCT. Let us briefly introduce the way to determine whether there exist feasible solutions of (P2) for the given b i 's.…”

“…Let us briefly introduce the way to determine whether there exist feasible solutions of (P2) for the given b i 's. In (29), for the star-topology WPCN using the HTT transmission way, we have studied the transmission completion time (TCT) minimization problem where each node N i needs to transmit b i bits to H-AP by using the minimal total amount of time and presented an algorithm for finding the optimal time allocations of WET and WITs to achieve the minimum TCT. So, for the given b i 's, if the minimum TCT T min of transmitting b i bits for each node N i is larger than one, no solution with period K ∑ i=0 T i = 1 can transmit b i bits for each node N i , that is to say, problem (P2) has no feasible solution.…”

Outage Probability Analysis and Power Splitter Designs for SWIPT Relaying Systems With Direct Link

“…In particular, simultaneous wireless information and power transfer (SWIPT) [1]- [3] and wireless powered communication networks (WPCN) [4] [5] techniques have received a lot of interest in energy constrained wireless networks, because radio frequency (RF) signals can become a convenient energy source. Meanwhile, relaying systems have been investigated in vast literature, due to its ability of extending cell coverage and improving reliability [6]- [10].…”