Communications of the ACS, Vol 2, No 001 (2009)

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A Hybrid Connection Admission Control Scheme for QoS Enhancement in UMTS/WLAN Overlay Networks

Tarek Bejaoui, Nidal Nasser


In this paper, we evaluate the performance of a hybrid and adaptive call admission control protocol for UMTS cellular networks with underlying tunnel-WLANs; either at the cell periphery or elsewhere within the UMTS coverage area. This CAC policy is proposed to limit the occurrence of hard IEEE 802.11 WLAN-UMTS handovers to mobiles using real time applications. It is based on the service class differentiation, the location in the heterogeneous infrastructure and a vertical handoff decision function as well. The results show that our policy achieves significant performance and gains. It maximizes the utilization of the resources available at the WLAN cells, and meets as much as possible the QoS requirement of higher priority users.

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