Decentralized Transmission Policies for Energy Harvesting Devices

TL;DR

This paper develops decentralized transmission policies for energy harvesting wireless devices, balancing collision and energy constraints, and demonstrates that optimal strategies are hybrid between orthogonal and symmetric schemes.

Contribution

It formulates a decentralized Markov decision process for energy harvesting devices and identifies the optimal trade-off between orthogonal and symmetric transmission schemes.

Findings

Orthogonal schemes are sub-optimal with energy harvesting.

Optimal policies balance collision probability and energy constraints.

Hybrid strategies outperform purely orthogonal or symmetric approaches.

Abstract

The problem of finding decentralized transmission policies in a wireless communication network with energy harvesting constraints is formulated and solved using the decentralized Markov decision process framework. The proposed policy defines the transmission probabilities of all devices so as to correctly balance the collision probabilities with the energy constraints. After an initial coordination phase, in which the network parameters are initialized for all devices, every node proceeds in a fully decentralized fashion. We numerically show that, because of the harvesting, a fully orthogonal scheme (e.g., TDMA-like) is sub-optimal in this scenario, and that the optimal trade-off lies between an orthogonal and a completely symmetric system.