Probing for Better Age of Information in Energy-Harvesting Random Access Networks

2026-04-28

AI Summary

This work addresses the challenge of minimizing the Age of Information (AoI) while balancing energy consumption and channel contention in a random-access network powered solely by energy harvesting. The authors propose three contention-based strategies leveraging channel sensing and reservation: Strictly Avoid Free Contention (SAFC), Reserved User Contention (RUC), and All-Active User Contention (AUC). Through stochastic process modeling, closed-form AoI derivation, and Monte Carlo simulations, the study demonstrates that AUC—permitting moderate contention—consistently achieves significantly lower AoI across diverse energy constraints, challenging the conventional wisdom that collisions must be strictly avoided in energy-limited systems. Furthermore, the results indicate that sensing overhead can be effectively amortized through increased transmission opportunities. Compared to conventional energy-harvesting slotted ALOHA, the proposed sensing-based mechanisms substantially enhance information freshness.

Abstract

In this paper, we investigate the impact of channel probing and reservation on the Age of Information (AoI) in energy-harvesting (EH) random access networks, where each source relies solely on harvested energy for status updating. To mitigate collisions, each node may expend a small amount of energy to send a probing signal before transmission, and a successful probe reserves the channel in the current slot. If probing fails, the node can either remain silent, termed strict avoid free competition (SAFC), attempt data transmission with a certain probability, termed reserved nodes competition (RUC), or adopt all-active nodes competition (AUC), where all energy-sufficient nodes may contend regardless of whether they probed. We derive closed-form expressions for the network-average AoI under these three schemes and validate them via simulations. The results show that AUC consistently achieves the lowest AoI by shortening the waiting time to convert harvested energy into successful updates. This finding challenges the conventional wisdom that strict collision avoidance is always optimal in energy-constrained systems, since allowing additional contention can effectively amortize probing overhead across more transmission opportunities. Comparisons with EH-enabled slotted ALOHA further show that probing-based access significantly outperforms direct transmission in energy-constrained regimes, highlighting channel probing as an effective approach to improving freshness.

Problem

• Age of Information
• Energy Harvesting
• Random Access
• Channel Probing
• Collision Avoidance

Innovation

• Age of Information
• energy harvesting
• channel probing
• random access
• collision management