Age of Information for Transmissions over Markov Channels.

We study status updates over wireless fading channels in terms of the age of information, which measures the freshness of the last received update since its generation. In this paper, we model the wireless transmission systems with Poisson arrivals, a First-Come-First-Served (FCFS) packet buffer, and two-state Markov modulated service process (MMSP) as M/MMSP/1/K queueing model. We derive closed-form expressions of average age of information in two extreme cases when the packet buffer size is either infinite or zero. Our analysis and simulation results show that the average age of information for M/MMSP/1/infinity queue greatly depends on channel variations and that M/MMSP/1/1 queue is more affected by packet arrival rate.