Maximal flow‐level stability of best‐rate schedulers in heterogeneous wireless systems

Abstract

We investigate flow‐level stability of schedulers in parallel‐service wireless systems, which is important for maximizing the base station's capacity to serve the heterogeneous flows that are within the base station's power range. We model such a system as a multi‐class queueing system with multiple preemptive servers, in which flows of different classes randomly arrive and depart once their flow is completed. The channel condition of a flow varies randomly over time because of fading and mobility. The evolution of the channel condition is assumed to be Markovian and class dependent. We focus on a general family of the best‐rate schedulers that, whenever possible, serve flows that are in the channel condition corresponding to the highest achievable class‐dependent transmission rate (i.e. the best rate). We prove under mild assumptions that any best‐rate scheduler achieves maximal stability, that is, stabilizes the system whenever possible, in all systems with generally distributed class‐dependent arrivals and flow sizes. Copyright © 2015 John Wiley & Sons, Ltd.

Whittle index approach to opportunistic scheduling with partial channel information

“…which can be verified by solving the following system of linear equations similar flow-level problems [8,14,16,12,30,32,1,2,13,34,15,3,6]) is based on a transient setting with a finite number of jobs in the beginning and no new arrivals later on. Still, as also done in many of the papers mentioned above, the developed Whittle index policies can be applied in the dynamic setting with new flows arriving randomly.…”

“…Such a flow-level opportunistic scheduling problem with IID or Markovian channel dynamics has earlier been studied under the assumption of exact channel information [8,14,12,9,18,30,32,1,2,13,34,15,3,6]. Near-optimal scheduling policies have successfully been developed by applying the Whittle index approach, which was originally developed for the restless bandits problems [36].…”

Queueing analysis of opportunistic scheduling with spatially correlated channels

“…If one relaxes the assumption that queue capacity is finite, conditions for the existence of a stationary solution are not entirely trivial, see e.g. [30] where the stability of a slightly different queueing system (with infinite capacities) is addressed.…”