Scheduling Algorithms for Minimizing Age of Information in Wireless Broadcast Networks with Random Arrivals
Age of information is a newly proposed metric that captures packet delay to end-users from an application layer perspective. The age measures the amount of time that elapsed since the latest information was generated at a source. In this context, we study an age minimisation problem over a broadcast network to keep many users updated on timely information, where only one user can be served at a time. We formulate a Markov decision process (MDP) to find dynamic scheduling algorithms, with the purpose of minimizing the long-run average age. We show that an optimal scheduling algorithm for the MDP is a simple stationary switch type. However, the optimal scheduling algorithm is not easy to implement due to the MDP's infinite state-space. Using a sequence of finite-state approximate MDPs, we successfully develop both optimal off-line and on-line scheduling algorithms. We validate the algorithms via numerical studies, and surprisingly show that the performance of no-buffer networks is very close to that of networks with buffers.
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