Knowledge-Based Call Admission Control with Bandwidth Reallocation in Wireless Multimedia Networks

Abstract

Wireless ATM is a promising technology for the next generation wireless multimedia networks, which is capable of supporting different services with different QoS (quality-of-service) requirements. Due to the scarcity of frequency spectrum, wireless ATM needs an efficient call admission control. Generally, blocking handoff calls is normally more annoying than blocking new calls. On the other hand, blocking new calls inevitably reduces resource utilization. A novel knowledge-based call admission control (KBCAC) is proposed to achieve high resource utilization as well as maintain new call blocking probability and forced termination probability at some acceptable levels in the multiservice wireless ATM networks with multiple CBR and ABR services. With KBCAC, new calls are accepted according to a service-dependent acceptance probability taking account of mobility, call holding time, and system state. To further reduce call blocking and forced termination, bandwidth reallocation of existing ABR calls is allowed if needed. An iterative algorithm is developed to calculate performance measures of interest, i.e., new call blocking probability and forced termination probability for CBR, and new call blocking probability, forced termination probability and average number of assigned time slots for ABR. Simulation results are shown to verify the accuracy of analytical results. Numerical results are also presented to show the robustness of KBCAC.