Analysis Methodology for Age of Information under Sequence Based Scheduling

TL;DR

This paper analyzes the Age of Information performance in a sequence-based scheduling system for status updates, focusing on the challenging case where the status generation period is shorter than the scheduling period, and proposes optimized sequence schemes.

Contribution

It extends previous analysis to the case where status generation is faster than scheduling, develops a mathematical tool using integer partitions, and proposes an optimized sequence scheme with lower AoI and energy consumption.

Findings

Proposed sequence scheme outperforms baselines in AoI performance.

Derived closed-form expressions for AoI when $T<L$.

Developed an algorithm to optimize sequence construction parameters.

Abstract

We focus on the Age of Information (AoI) performance in a system where each user generates packets periodically to send to a common access point (AP) for status updating. To avoid heavy overhead, we assume that channel sensing, feedback information from the AP, and time synchronization are not available in the system. We adopt a multi-access scheme called the sequence scheme, where each user is assigned a periodic binary sequence to schedule their transmissions. In our previous work [18], we have thoroughly studied the AoI performance under sequence scheme when the period of schedule sequences, $L$, is equal to the status generating period, $T$. The results can be extended to the case where $T>L$. However, the case of $T<L$ is not covered by [18]. Therefore, in this paper, we concentrate on analyzing the AoI performance in the case of $T<L$, which is more challenging and requires different approaches. We conduct in-depth analysis on this case and develop a mathematical tool based on integer partitions to facilitate the analysis. We derive low-complexity closed-form expressions for two scenarios under $T<L$. Based on the obtained analytical results, we propose an algorithm to optimize the construction parameters of the sequence scheme. Finally, we compare our proposed sequence scheme with two commonly used baselines, and show that our proposed scheme outperforms the baselines in terms of AoI performance while consuming less energy.