線路交換與封包交換網路間語音通話連續性之通道保留機制

Abstract

UMTS (Universal Mobile Telecommunications System) 的核心網路包含線路交換領域 (Circuit-Switched Domain) 與封包交換領域 (Packet-Switched Domain)。UMTS手機可以在線路交換領域或是封包交換領域撥打或接聽電話。在通話過程中，使用者可以在不同的領域間切換，稱之為領域轉換 (Domain Transfer)。領域轉換的重要議題之ㄧ是轉換延遲時間。為達到快速的轉換，本論文提出通道保留機制 (Bearer Reservation with Preemption)，並以理論推導和模擬驗證對通道保留機制進行效能分析。研究結果顯示，通道保留機制的優異效能在使用者行為愈不規則時成效愈顯著。

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 UMTS handset can initiate or receive a call in either the CS or the PS domain. During the call, the user may switch from one domain to another. The switching overhead is an important concern of domain transfer. In this thesis, we propose the Bearer Reservation with Preemption (BRP) scheme to support fast domain transfer, and develop both analytic analysis and simulation experiments to investigate the BRP performance. Our study indicates that when user behavior is more irregular, the advantage of the BRP scheme becomes significant.