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Abstract:
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The use of mobile communication is increasing strongly. This will increase the amount of data transported in the mobile communication core network. Because of this, the efficiency of the data transportation in the mobile core network needs to be improved. Also demands of new kind of services are rising. The services provided by the mobile network in the future can no longer be defined by the technology used in the mobile network. Utilisation of any kinds of services imaginable is demanded.- This had lead to a new approach in defining the mobile system. The bearer will be separated from the services. The networks operators of the future are merely selling bearer service and basic services such as multimedia calls. The bearer service is transparent to the actual application services provided through theses bitpipes. The users, network operators or 3rd parties can more easily provide the application services.- Variety of multimedia services and the new application services of the future will have only one thing in common. Efficient transport for the services in the core network can only be provided with packet switched technology. Also the user need to be charged based on the actual data transported by users. The charging can no longer be based on the time the connection to the core network is open, like in current core networks that are implemented with circuit switched technologies. However, the circuit switched networks cannot be disposed. Huge assets have been made to them and they still have unused resources. Because of this, the new system has to be compatible with the old system.- The standardisation organisations, core network element and mobile equipment manufacturers and network operators formed a co-operational organisation, the 3rd Generation Partnership Project (3GPP). Its main task is to specify a new mobile communications system and is based on IP transport technology. The technology used does not define the services that can be provided with the system. The system is independent of the used access technology. The system is called the Universal Mobile Telecommunication System (UMTS).- The UMTS consists of four different subsystems. The Circuit Switched Core Network domain (CS CN) provides compatibility for current circuit switched telephone networks. Because the expensiveness of current PCM leased line transports, the circuit switched technology is emulated with cheaper, but reliable IP over ATM transport. The IP Multimedia Core Network system (IM CN SS) provides multimedia services such as videoconferences and other multimedia calls. The Packet Switched Core Network domain (PS CN) provides mobile access to the IM CN SS and hides the user's mobility from it. The application services are provided in the Services subsystem.- This thesis focuses on the Cx- interface in the IM CN SS: The Cx interface is used for mobility management and call control in the IM CN SS between the Home Subscriber Server (HSS) and the Call State Control Function (CSCF). Several protocol alternatives have been proposed in the3GPP to implement the Cx-interface. The alternatives most likely to be selected are Light Weight Directory Access Protocol version 3 (LDAP v3) or Extensible Markup Language (XML) nested in Hypertext Transfer Protocol (HTTP) with Session Initiation Protocol (SIP):- The purpose of this thesis is to study the protocols themselves and their suitability for call control and mobility management in the IM CN SS. The operation of the protocols, their operation in the IM CN SS, the possibilities they offer to the IM CN SS are studied and the two alternatives are compared with each other. 3GPP has selected SIP as the call control protocol in the IM CN SS. This document evaluates two alternatives for mobility management in the Cx-interface. The Alternatives are HTTP with XML and LDAP. /Kir10 |