IMS域的位置管理策略研究

Research on Location Management of IMS

UMTS(Universal Mobile Telecommunications System)R6中IMS(IP Multimedia Subsystem)域的用户的位置都要注册到归属地网络,而且终端的所有SIP信令都要经过注册服务器,导致用户在漫游状态下控制信令的迂回路径变长并限制了用户对网络中应用的使用。该文对UMTS R6的IMS位置管理方案进行了改进,提出了IMS用户位置信息的分布式管理和联系人位置信息自适应缓存机制,使得其漫游状态下的位置注册和呼叫建立过程更加迅速。分析及仿真显示:新的位置管理策略从网络信令花费上优于原位置管理策略。

In the IMS（IP Multimedia Subsystem） specification of UMTS（Universal Mobile Telecommunications System） R6, the user must register its location in its home registrar. The session signaling have to reach its home registrar when user is not in home network, which results in the session path longer than the media path and defining the users to its home services. A new location management schedule and an auto-adjustable caching algorithm are proposed, so that the session signaling need not pass the home registrar but directly from original user＇s visited network to terminate user＇s network. The results of Simulation and analysis shows the new schedule get the benefit in cost and time.