SIP-based Applications in UMTS: A Performance Analysis

With the ever increasing penetration of IP technologies and the tremendous growth in wireless data traffic, the wireless industry is evolving the mobile core networks towards all IP technology. The 3 Generation Partnership Project (3GPP) is specifying an IP Multimedia Sub-system (IMS) in UMTS Release 5/6, which is adjunct to the UMTS Packet Switched (PS) GPRS CN. This IPbased network will allow mobile operators to provide commonly used Internet applications to wireless user. The UMTS IMS uses the Internet Engineering Task Force (IETF) defined text-based Session Initiation Protocol (SIP), to control a wide range of anticipated IP-based services offering new services such as multimedia calls, chat, presence services. Initial indications as to the signalling delay associated with SIP messages have concerned operators about the viability of such services over the UMTS air interface. This paper provides an insight into the UMTS system performance, focusing on the UMTS SIP-based service where typical delay-sensitive and non-sensitive applications, such as chat and messaging services are studied. Furthermore we discuss and analyse the requirements and possible solutions for the efficient use of SIP in a wireless environment, such as protocol compression.