Scheduling to Minimize Age of Synchronization in Wireless Broadcast Networks with Random Updates

Abstract

In this work, a wireless broadcast network with a base station (BS) sending random time-sensitive information updates to multiple users with interference constraints is considered. The Age of Synchronization (AoS), namely the amount of time elapsed since the information stored at the network user becomes desynchronized, is adopted to measure data freshness from the perspective of network users. Compared with the more widely used metric—the Age of Information (AoI), AoS accounts for the freshness of the randomly changing content. We formulate the scheduling problem into a discrete time Markov decision process and approximate the optimal solution through finite state policy iteration. An index based heuristic scheduling policy based on restless multi-arm bandit (RMAB) is provided to reduce computational complexity. Numerical results are presented to demonstrate the performance of the proposed policies.