Scheduling Policies in a Multi-Source Status Update System with Dedicated and Shared Servers

TL;DR

This paper investigates scheduling policies in a multi-source status update system with both dedicated and shared servers, aiming to optimize information freshness (AoI) amidst multi-path and link-sharing challenges.

Contribution

It introduces an optimal probabilistic scheduler and heuristic cyclic algorithms for shared servers in multi-path networks with generate-at-will transmissions.

Findings

Optimal probabilistic scheduler derived for the system.

Heuristic cyclic scheduling algorithms proposed.

Algorithms effectively reduce the weighted average age of information.

Abstract

Use of multi-path network topologies has become a prominent technique to assert timeliness in terms of age of information (AoI) and to improve resilience to link disruptions in communication systems. However, establishing multiple dedicated communication links among network nodes is a costly endeavor. Therefore, quite often, these secondary communication links are shared among multiple entities. Moreover, these multi-path networks come with the added challenge of out-of-order transmissions. In this paper, we study an amalgamation of the above two aspects, i.e., multi-path transmissions and link sharing. In contrast to the existing literature where the main focus has been scheduling multiple sources on a single shared server, we delve into the realm where each source sharing the shared server is also supplemented with its dedicated server so as to improve its timeliness. In this multi-path link sharing setting with generate-at-will transmissions, we first present the optimal probabilistic scheduler, and then propose several heuristic-based cyclic scheduling algorithms for the shared server, to minimize the weighted average age of information of the sources.