Tier-Based Analytical Model for Adaptive Call Admission Control Scheme in a UMTS-WCDMA System

UMTS (Universal Mobile Telecommunications System) uses WCDMA (wideband code division multiple access) as its radio interface. The main advantage of this is flexibility in resource management. UMTS systems are based on a hierarchical cellular structure that provides high data rates with extended mobile speeds. Mobility causes resource allocation complications in the concerned cell and the cellular neighborhood. In addition, the heterogeneous nature of users in the UMTS systems requires quality of service (QoS) guarantee for each type of service (ToS). This paper proposes that higher bandwidth utilization can be achieved by managing the resource allocation at a bigger neighborhood level. Higher bandwidth utilization leads to lower blocking and dropping probabilities, which are the main QoS parameters that are addressed in this paper. The prevalent call admission control schemes are used to simulate the UMTS-WCDMA system. The system is first recognized as a multirate, multi-class, priority based system. The tier-based cellular structure is then proposed and analytically modeled.