The CAC Model and QoS Management in Wireless Multiservice Network

Call admission control (CAC) is a key for ensuring the quality of service (QoS) in wireless multiservice network. With the advances in wireless communication technology and the growing interest in deploying multimedia services in wireless networks, the issue of providing an efficient CAC has come to the fore. A suitable CAC for the multimedia service networks is expected to make efficient use of the scarce wireless resource while supporting different services with different QoS metrics. In this paper, we propose a CAC model with four priority levels supporting five classes of service (e.g. UGS, ErtPS, rtPS, nrtPS and BE) in a wireless multiservices network: IEEE 802.16e. The idea is to design an efficient CAC that deals with new and handovers (HO) calls. The proposed model manages to establish priority between new end handover calls. It is assumed that the system operates under a reservation channel scheme and a queuing strategy in order to maintain the HO priority. Our model must maintain a balance between two conflicting requirements: maximise the resource utilisation and minimize the forced handover call dropping rate. In order to maintain the maximum resource utilisation, the maximum number of calls should be admitted into a network which may result in unacceptably high HO call dropping rates due to insufficient resources for HO calls. It is very important to propose a CAC model with reserves the minimum amount of necessary resources to maintain an acceptable HO call dropping and provide high resource utilisation. Keywords-Wireless multiservice network : IEEE 802.16e, CAC, resource allocation, mobility, QoS.