Minimum Age TDMA Scheduling

TL;DR

This paper studies the Min-Age scheduling problem in TDMA channels, introduces a related Min-WCS problem, and provides approximation and exact algorithms, establishing NP-hardness of the original problem.

Contribution

It introduces the Min-WCS problem, links it to Min-Age scheduling, and offers new approximation and exact algorithms while proving NP-hardness.

Findings

A 2.733-approximation algorithm for Min-WCS

An exact dynamic programming algorithm for Min-WCS

NP-hardness of the Min-Age problem

Abstract

We consider a transmission scheduling problem in which multiple systems receive update information through a shared Time Division Multiple Access (TDMA) channel. To provide timely delivery of update information, the problem asks for a schedule that minimizes the overall age of information. We call this problem the Min-Age problem. This problem is first studied by He \textit{et al.} [IEEE Trans. Inform. Theory, 2018], who identified several special cases where the problem can be solved optimally in polynomial time. Our contribution is threefold. First, we introduce a new job scheduling problem called the Min-WCS problem, and we prove that, for any constant $r \geq 1$, every $r$-approximation algorithm for the Min-WCS problem can be transformed into an $r$-approximation algorithm for the Min-Age problem. Second, we give a randomized 2.733-approximation algorithm and a dynamic-programming-based exact algorithm for the Min-WCS problem. Finally, we prove that the Min-Age problem is NP-hard.