Optimal control of preemptive systems with loss

We consider the problem of optimal preemption control in preemptive systems with loss. Based on a designed cost function composed by the following criteria: blocking cost function, preemption cost function, degradation cost function, and processing and signaling load cost function; we use the semi-Markov decision process framework as well as the value iteration algorithm to get the optimal policies. To evaluate the optimal policies, we outline their structures and the system performance for different configurations. An interesting result happens when the lower priority service becomes profitable. In this case, the performance of higher priority calls, which have the right to preempt, may be degraded. This is against the well known traffic engineering, which is solely concentrated on the resource guarantee characteristic of the preemptive priority that always improves the higher priority call performance by lowering its blocking probability.

Graphical abstractThe paper deals with the design of an optimal controller in a communication link with multiple service classes, which can come from different traffic sources. The optimal design consists of choosing one of the following actions: Acceptation (A), Acceptation with Preemption (AP) or Blocking (B) a higher priority call (HPC) service request. When an action AP is chosen, the lower priority call (LPC) is disconnected from the system (event -D).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We model preemptive systems with loss by means of Semi-Markov Decision Process (SMDP) framework. ► A new cost function for evaluating the performance of preemptive systems with loss is proposed. ► Results indicate that higher priority calls QoS may be degraded when lower priority calls become more profitable.