Optimal Power Allocation for Energy Harvesting and Power Grid Coexisting Wireless Communication Systems

TL;DR

This paper investigates optimal power allocation strategies for wireless systems that co-manage energy harvesting and grid power, proposing policies that minimize grid energy use under various data and energy arrival scenarios.

Contribution

It introduces the two-stage water filling policy and reverse multi-stage water filling policy for optimal power allocation in energy harvesting and grid coexisting systems, including heuristic online schemes.

Findings

Optimal policies minimize grid power consumption.

Water filling policies effectively allocate harvested and grid energy.

Heuristic schemes perform well in simulations.

Abstract

This paper considers the power allocation of a single-link wireless communication with joint energy harvesting and grid power supply. We formulate the problem as minimizing the grid power consumption with random energy and data arrival, and analyze the structure of the optimal power allocation policy in some special cases. For the case that all the packets are arrived before transmission, it is a dual problem of throughput maximization, and the optimal solution is found by the two-stage water filling (WF) policy, which allocates the harvested energy in the first stage, and then allocates the power grid energy in the second stage. For the random data arrival case, we first assume grid energy or harvested energy supply only, and then combine the results to obtain the optimal structure of the coexisting system. Specifically, the reverse multi-stage WF policy is proposed to achieve the optimal power allocation when the battery capacity is infinite. Finally, some heuristic online schemes are proposed, of which the performance is evaluated by numerical simulations.