An integrated admission-degradation framework for optimizing real-time call mix in wireless cellular networks

This paper describes an integrated framework for selecting optimal call mixes (in a multimedia traffic scenario) by bandwidth degradation in a wireless cellular network, to maximize the revenue earned by the service provider. Each admitted call in our framework generates a revenue for the service provider based on the parameters of the call. The sum of the revenues generated by all admitted calls at a time is considered as the total revenue earned in a cell. By degradation, we mean that: (1) some channels can be taken away from ongoing calls that are assigned multiple channels and/or (2) newly admitted calls that require multiple channels get fewer than what they requested. To avoid removing more channels from calls than they could tolerate, we incorporate a new call attribute: the degradation tolerance, i.e, the number of channels a call can be degraded without sacrificing the acceptable level of quality. We also consider priorities over calls to influence the admission-degradation decision. Our analytical framework includes both static and dynamic scenarios. The dynamic case is enhanced with the ability to select the optimal call mix using incoming and departing handoffs, new calls, and call terminations in a recursive way. We also discuss how to accommodate non-real-time calls into our system. To evaluate the performance of the proposed scheme a discrete event simulation tool, that accommodates our dynamic framework built on a customized simulated annealing optimization function, has been developed. Simulation results demonstrate that not only does the proposed integrated admission-degradation framework maximize the total revenue earned in cells, but also handoff and new call blocking probabilities are reduced.