Scheduling Policies for Minimizing Age of Information in Broadcast Wireless Networks

TL;DR

This paper investigates scheduling policies in wireless broadcast networks to minimize the Age of Information, proposing new low-complexity policies with performance guarantees and demonstrating their effectiveness through numerical simulations.

Contribution

It introduces novel low-complexity scheduling policies with proven performance guarantees for minimizing AoI in unreliable wireless networks.

Findings

Max-Weight and Whittle's Index policies outperform others in simulations.

Greedy policy is optimal in symmetric networks.

Proposed policies achieve near-optimal performance across configurations.

Abstract

We consider a wireless broadcast network with a base station sending time-sensitive information to a number of clients through unreliable channels. The Age of Information (AoI), namely the amount of time that elapsed since the most recently delivered packet was generated, captures the freshness of the information. We formulate a discrete-time decision problem to find a transmission scheduling policy that minimizes the expected weighted sum AoI of the clients in the network. We first show that in symmetric networks a Greedy policy, which transmits the packet with highest current age, is optimal. For general networks, we develop three low-complexity scheduling policies: a randomized policy, a Max-Weight policy and a Whittle's Index policy, and derive performance guarantees as a function of the network configuration. To the best of our knowledge, this is the first work to derive performance guarantees for scheduling policies that attempt to minimize AoI in wireless networks with unreliable channels. Numerical results show that both Max-Weight and Whittle's Index policies outperform the other scheduling policies in every configuration simulated, and achieve near optimal performance.