Scheduling Policies in a Multisource Status Update System With Dedicated and Shared Servers

Use of multipath 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 multipath networks come with the added challenge of out-of-order transmissions. In this article, we study an amalgamation of the above two aspects, i.e., multipath 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 multipath 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 AoI of the sources.