Performance estimation of UMTS release 5 IM-subsystem elements

Universal Mobile Telecommunications System (UMTS) is the third generation (3G) mobile communications systems specified by the European Telecommunications Standards Institute (ETSI) and the world-wide 3G Partnership Project (3GPP) within the framework defined by the International Telecommunication Union (ITU) and known as International Mobile Telecommunications-2000 (IMT-2000). ETSI and 3GPP are introducing UMTS in phases and annual releases. UMTS is a 3G GSM successor standard using the GSM phase 2+ enhanced core networks. Currently, there is an evolution from GSM phase 2+ core network towards the UMTS release 5 multiservice packet network. This process is characterized by creating the Internet Protocol (IP) multimedia core network subsystem (IM-subsystem), which includes elements necessary to support IM services in UMTS. Traffic patterns generated by IM services are different from traditional Poisson models used for circuit switched voice traffic. As a result, network parameters can be underestimated, and a UMTS network planning problem arises. For successful solution of the problem, it is necessary to estimate the performance of IM-subsystem elements. We analyze the performance of the gateway GPRS support node (GGSN) on the basis of the FBM/D/1/W queueing system (FBM - fractional Brownian motion). Submitted results may be applied for the estimation of parameters of UMTS release 5 IM-subsystem elements.