The Dynamic Behavior of Frameless ALOHA: Drift Analysis, Throughput, and Age of Information

TL;DR

This paper analyzes the dynamic behavior of frameless ALOHA, focusing on throughput and age of information, considering variable terminal contention, stability via drift analysis, and the impact of protocol parameters on AoI.

Contribution

It introduces a drift analysis for stability and provides an exact AoI characterization, revealing trade-offs between throughput optimization and AoI performance.

Findings

Throughput and AoI are affected by protocol parameters.

Maximizing throughput can degrade AoI performance.

Stable and unstable equilibrium points are identified.

Abstract

We study the dynamic behavior of frameless ALOHA, both in terms of throughput and age of information (AoI). In particular, differently from previous studies, our analysis accounts for the fact that the number of terminals contending the channel may vary over time, as a function of the duration of the previous contention period. The stability of the protocol is analyzed via a drift analysis, which allows us to determine the presence of stable and unstable equilibrium points. We also provide an exact characterization of the AoI performance, through which we determine the impact of some key protocol parameters, such as the maximum length of the contention period, on the average AoI. Specifically, we show that configurations of parameters that maximize the throughput may result in a degradation of the AoI performance.