# A Unified Sampling and Scheduling Approach for Status Update in Multiaccess Wireless Networks

## TL;DR

This paper introduces a unified sampling and scheduling method for decentralized status updates in multiaccess wireless networks, significantly improving tracking accuracy over separate approaches through theoretical analysis and simulations.

## Contribution

It develops a unified $ ext{S}^2$ approach combining sampling and scheduling, with analytical solutions and validation for decentralized status update optimization.

## Key findings

- Unified approach outperforms separate methods in status tracking error
- Closed-form Whittle's index derived for Wiener process sources
- Simulation confirms the scheme's optimality and advantages

## Abstract

Information source sampling and update scheduling have been treated separately in the context of real-time status update for age of information optimization. In this paper, a unified sampling and scheduling ($\mathcal{S}^2$) approach is proposed, focusing on decentralized updates in multiaccess wireless networks. To gain some insights, we first analyze an example consisting of two-state Markov sources, showing that when both optimized, the unified approach outperforms the separate approach significantly in terms of status tracking error by capturing the key status variation. We then generalize to source nodes with random-walk state transitions whose scaling limit is Wiener processes, the closed-form Whittle's index with arbitrary status tracking error functions is obtained and indexability established. Furthermore, a mean-field approach is applied to solve for the decentralized status update design explicitly. In addition to simulation results which validate the optimality of the proposed $\mathcal{S}^2$ scheme and its advantage over the separate approach, a use case of dynamic channel state information (CSI) update is investigated, with CSI generated by a ray-tracing electromagnetic software.