Minimum Length Scheduling for Power Constrained Harvest-then-Transmit Communication Networks

Abstract

We consider a wireless powered, harvest-thentransmit communication network, which consists of a single antenna, energy and information access point (AP) and multiple, single antenna, batteryless users with energy harvesting capabilities. At the beginning of a time frame, the AP broadcasts energy in the downlink to the users. Then, users transmit their data to the AP in the uplink, using their harvested energy. We formulate the optimization problem with the objective of minimizing the total schedule length, subject to the constraints on the minimum amount of data to be sent to the AP, and unlike previous studies, the maximum transmit power for the information transmission. This problem is nonlinear and non-convex. The solution is based on bi-level optimization, consisting of optimizing the transmit power allocation of the nodes for a given energy harvesting time and searching over harvesting time allocation. We also propose a heuristic algorithm in which we incorporate the optimal solution of a single user network. Simulation results demonstrate that under appropriate network conditions, our proposed algorithms provide close-to-optimal results with a reasonable run time compared to another time minimization algorithm which does not integrate the uplink power constraint.

Minimum Length Scheduling for Multi-Cell Wireless Powered Communication Networks

“…The goal of the simulations is to compare the performance of the proposed algorithm, MAMUSA to POWMU [6], MAX-EH [6] and Transmission Completion Time-minimized Algorithm (TCT) [5] and evaluate the effect of the simultaneous transmission on the network performance. POWMU, MAX-EH and TCT schedule users' ITs for single AP multiple user EH networks where simultaneous transmission is not allowed.…”

“…Total time is minimized for full-duplex WPCNs for continuous [3] and discrete [4] rate assumptions. A half-duplex WPCN is studied for total time minimization with the minimum amount of information to be transmitted in [5], and, additionally with the maximum UL power limit in [6].…”

Relay Selection, Scheduling and Power Control in Wireless Powered Cooperative Communication Networks

“…The transmit power is further limited by the amount of the harvested energy given in Eq. (1). The required energy for decoding the received message at relays is negligible compared to the energy consumption for IT [11].…”

“…For the solution of Problem (5), we first formulate a sub-problem on scheduling and power control for WPCN with multiple source-destination pairs and an AP as energy source, which is the reduced form of the original problem for a given relay selection. A preliminary version of this problem and the solution algorithms has previously appeared in [1]. Then, the best relay selection is searched either by BB based techniques or an improvement type heuristic approach.…”

“…( 10) and (11), respectively. For the details of this proof, please refer to [1]. Definition 1. τS 1 and τ0 are defined as the values of τ S 1 and τ 0 , respectively, in the solution of the system, when constraints (6b)-(6d) hold with equality, and expressed by…”