Research And Design Of Emergency Call Service Of Ims Network

Emergency Call (EC) refers that people carry out the necessary communication with the emergency call center by the use of communication resources to keep their life and property away from danger when faced with an emergency. As a kind of traditional telecom service, EC was controlled by traditional circuit network previously. But with the rapid development of the technology of IMS (IP Multimedia Subsystem), it is widely accepted that IMS is gradually becoming the core of next generation network with the advantage of openness and independent access. This paper will carry on an in-depth reserach on emergency call service of IMS network and put forword the relevant design.In the process of the long term evolution of the network, the situation that multiple accessing options coexist while IMS being the core network will exist for a long time:for fixed access, the situation means the coexistence of CS access and IP access; for mobile access, the situation means the coexistence of LTE (Long Term Evolution) and2G/3G network. This paper will respectively research and design the emergency call service of fixed access which contains two situations-allers in CS domain and callers in IMS domain and different types of mobile access exist in different periods of LTE’s development. In order to implement the emergency call service, first thing is to solve three key problems-how to obtain the location information of the callers, how to route the emergency call to the nearest emergency center, how to ensure the accessibility of the speech. Besides, to emergency call of mobile access to IMS, it is also necessary to consider the special situation-covering domain shifts during emergency call, callers make an emergency call in a roaming situation and so on.This paper first analyzes and solves the key problems, then according to the principle-"reducing deployment costs and in line with the network evolution direction" designs the network architecture and call process based on the existing network architecture and network element.In order to validate the feasibility of the design, this paper provides relevant test cases which have been tested on devices of different venders on relevant platform of one carriers. The test cases have passed the test which prove the design is feasible.