Age of Information in Slotted ALOHA With Energy Harvesting

TL;DR

This paper analyzes the age of information in an energy-harvesting slotted ALOHA system, deriving analytical metrics and proposing strategies to optimize information freshness and throughput.

Contribution

It introduces an analytical framework for AoI in energy-harvesting ALOHA systems and compares strategies for minimizing AoI under different conditions.

Findings

Transmitting whenever possible reduces AoI at low update rates.

Transmitting only when energy is sufficient benefits high update rates.

An optimized hybrid strategy outperforms individual strategies in AoI and throughput.

Abstract

We examine the age of information (AoI) of a status update system that incorporates energy harvesting and uses the slotted ALOHA protocol. We derive analytically the average AoI and the probability that the AoI exceeds a given threshold. Via numerical results, we investigate two strategies to minimize the age of information (AoI): transmitting a new update whenever possible to exploit every chance to reduce the AoI, and transmitting only when sufficient energy is available to increase the chance of successful delivery. The two strategies are beneficial for low and high update generation rates, respectively. However, an optimized approach that balances the two strategies outperforms them significantly in terms of both AoI and throughput.