Impact of Signaling Load on the UMTS Call Blocking/Dropping

Radio resources in third generation (3G) wireless cellular networks (WCNs) such as the universal mobile telecommunications system (UMTS) network are limited in terms of soft capacity. The quality of a signaling service transmission depends on various factors (i.e., a user´s location, speed, and data rate requirement), and has an impact on the quality of user data communications where the opposite is also true. In this paper, we provide the first step to evaluate the impact that various signaling service types have on call blocking and ongoing call dropping in UMTS systems. The radio resource´s acquisition time for various signaling services is calculated according to the specifications in UMTS standards. The maximum number of sessions that a signaling service type can transmit simultaneously is estimated along with the impact when other signaling service types are transmitted. Our analysis reduces the computational complexity in the call admission control (CAC) and allows the preservation of classes of services. An example traffic scenario is given illustrating the benefit of our study.