Age of Information in Random Access Networks with Energy Harvesting

TL;DR

This paper analyzes the age of information in energy-harvesting random access networks, deriving analytical expressions and optimizing parameters to minimize AoI under energy constraints.

Contribution

It provides a novel analytical framework combining Markov chains and stochastic geometry for AoI in energy-harvesting networks, with closed-form results for specific buffer sizes.

Findings

Optimal update rate is one in energy-constrained regimes.

Small buffer size (one transmission) suffices for optimal performance.

Derived explicit expressions for average AoI in special cases.

Abstract

We study the age of information (AoI) in a random access network consisting of multiple source-destination pairs, where each source node is empowered by energy harvesting capability. Every source node transmits a sequence of data packets to its destination using only the harvested energy. Each data packet is encoded with finite-length codewords, characterizing the nature of short codeword transmissions in random access networks. By combining tools from bulk-service Markov chains with stochastic geometry, we derive an analytical expression for the network average AoI and obtain closed-form results in two special cases, i.e., the small and large energy buffer size scenarios. Our analysis reveals the trade-off between energy accumulation time and transmission success probability. We then optimize the network average AoI by jointly adjusting the update rate and the blocklength of the data packet. Our findings indicate that the optimal update rate should be set to one in the energy-constrained regime where the energy consumption rate exceeds the energy arrival rate. This also means if the optimal blocklength of the data packet is pre-configured, an energy buffer size supporting only one transmission is sufficient.