Bearer Reservation with Preemption for Voice Call Continuity

In universal mobile telecommunications system (UMTS), the core network consists of two service domains: the circuit-switched (CS) and the packet-switched (PS) domains. A call can be set up in either the CS or the PS domain. This call may be switched (transferred) between the CS and the PS domains. A major concern of domain transfer is the switching overhead. In this paper, we propose the Bearer Reservation with Preemption (BRP) scheme to support fast domain transfer, and propose a simulation model to investigate the BRP performance. Our study shows that when user behavior is irregular, the BRP scheme can effectively reduce the re-connection overhead.