Method and System for Providing an Emergency Location Service

Abstract

Provided are a method and a system for providing an emergency location service using an IMS core. In the method, when the IMS core receives an emergency call initiating request message from a user equipment, the IMS core transmits a location service request message requesting for retrieving a location of the user equipment to a location retrieval subsystem in response to the emergency call initiating request message. Then, when the IMS core receives current location information of the user equipment, which is acquired through an access to the user equipment by the location retrieval subsystem having received the location service request message, from the location retrieval subsystem, the IMS core selects an emergency center on the basis of the current location information and transmits the emergency call initiating request message including the current location information to the selected emergency center. Then, an emergency call is established between the user equipment and the emergency center.

1 . A method for providing an emergency location service using an IP multimedia subsystem (IMS) core, the method comprising the steps of:
 receiving an emergency call initiating request message from a user equipment;   transmitting a location service request message requesting for retrieving a location of the user equipment to a location retrieval subsystem in response to the emergency call initiating request message;   receiving a location service response message including current location information of the user equipment, which is acquired through an access to the user equipment by the location retrieval subsystem having received the location service request message, from the location retrieval subsystem; and   selecting an emergency center on the basis of the current location information and transmitting the emergency call initiating request message including the current location information to the selected emergency center.   
     
     
         2 . The method according to  claim 1 , further comprising establishing an emergency call between the emergency center having received the emergency call initiating request message and the user equipment. 
     
     
         3 . The method according to  claim 1 , wherein the location retrieval subsystem is a location retrieval function(LRF). 
     
     
         4 . The method according to  claim 1 , wherein the location service request message includes identification information of the user equipment. 
     
     
         5 . The method according to  claim 4 , wherein the identification information of the user equipment includes a session initiation protocol uniform resource identifier (SIP URI) or a telephone uniform resource identifier (TEL URI). 
     
     
         6 . The method according to  claim 4 , wherein the location service request message further includes an IP address of the user equipment. 
     
     
         7 . The method according to  claim 1 , wherein the location service request message includes identification information of an IP-connectivity access network (IP-CAN) for allowing the user equipment to access the IMS core. 
     
     
         8 . The method according to  claim 1 , wherein the emergency call initiating request message received from the user equipment includes initial location information of the user equipment. 
     
     
         9 . The method according to  claim 8 , wherein the step of transmitting the location service request message to the location retrieval subsystem is performed when the initial location information is not suitable for selecting an emergency center. 
     
     
         10 . The method according to  claim 8 , wherein the initial location information is acquired by using the IP-CAN for allowing the user equipment to access the IMS core or by enabling the user equipment to access directly the location retrieval subsystem. 
     
     
         11 . The method according to  claim 1 , wherein in the step of transmitting the emergency call initiating request message to the emergency center, ID information of the emergency center is also transmitted. 
     
     
         12 . The method according to  claim 11 , wherein the ID information of the emergency center includes at least one of an emergency service routing digit (ESRD), an emergency service routing key (ESRK), an emergency service routing number (ESRN), and an emergency service query key (ESQK). 
     
     
         13 . A method for providing an emergency location service, comprising the steps of:
 transmitting an emergency call initiating request message from a user equipment to an IP multimedia subsystem (IMS) core;   transmitting a first location service request message requesting for retrieving a location of the user equipment from the IMS core to a location retrieval subsystem;   acquiring, by the location retrieval subsystem which accesses the user equipment, current location information of the user equipment in response to the first location service request message;   transmitting a first location service response message including the current location information from the location retrieval subsystem to the IMS core;   transmitting the emergency call initiating request message including the current location information from the IMS core to a emergency center which is selected by the IMS core on the basis of the received current location information; and   establishing an emergency call between the emergency center and the user equipment in response to the received emergency call initiating request message.   
     
     
         14 . The method according to  claim 13 , wherein the location retrieval subsystem is a location retrieval function (LRF). 
     
     
         15 . The method according to  claim 13 , wherein the emergency call initiating request message received from the user equipment includes initial location information of the user equipment, and
 wherein the step of transmitting the first location service request message to the location retrieval subsystem is performed when the initial location information is not suitable to select the emergency center.   
     
     
         16 . The method according to  claim 13 , wherein the first location service request message includes identification information of the user equipment and identification information of the IP-CAN allowing the user equipment to access the IMS core. 
     
     
         17 . The method according to  claim 13 , wherein the procedure of acquiring the current location information is performed using a user plane-based location service procedure. 
     
     
         18 . The method according to  claim 17 , wherein the location service procedure is a secure user plane location (SUPL) procedure, and
 wherein the location retrieval subsystem includes an emergency SUPL location platform (E-SLP), a home SUPL location platform (H-SLP), or a visited SUPL location platform (V-SLP)   
     
     
         19 . The method according to  claim 13 , after the step of establishing the emergency call, further comprising the steps of:
 transmitting a second location service request message from the emergency center to the location retrieving subsystem;   acquiring, by the location retrieval subsystem, updated location information of the user equipment in response to the second location service request message; and   transmitting the updated location information from the location retrieval subsystem to the emergency center.   
     
     
         20 . The method according to  claim 19 , wherein the procedure of acquiring the updated location information is performed using an SUPL procedure, and wherein the location retrieval subsystem includes an E-SLP, an H-SLP, or a V-SLP. 
     
     
         21 . The method according to  claim 13 , wherein in the step of transmitting of the emergency call initiating request message to the emergency center, information of identifying the emergency center is also transmitted. 
     
     
         22 . The method according to  claim 21 , wherein the ID information of the emergency center includes at least one of an emergency service routing digit (ESRD), an emergency service routing key (ESRK), an emergency service routing number (ESRN), and an emergency service query key (ESQK). 
     
     
         23 . The method according to  claim 13 , the IMS core includes an emergency call session control function (E-CSCF) and an emergency application server (E-AS) providing the routing information of the emergency center. 
     
     
         24 . The method according to  claim 23 , wherein the E-CSCF is an entity taking charge of communication with the location retrieval subsystem and the selected emergency center. 
     
     
         25 . The method according to  claim 23 , wherein the E-AS is an entity taking charge of communication with the location retrieval subsystem and the selected emergency center. 
     
     
         26 . The method according to  claim 23 , wherein the E-CSCF is an entity taking charge of communication with the location retrieval subsystem, and the E-AS is an entity taking charge of communication with the selected emergency center. 
     
     
         27 . The method according to  claim 13 , before the step of transmitting the emergency call initiating request message from the user equipment, further comprising the steps of:
 transmitting a registration request message from the user equipment to the IMS core; and   transmitting an access acknowledgement message from the IMS core to the user equipment in response to the registration request message.   
     
     
         28 . A method for providing an emergency location service, the method comprising the steps of:
 transmitting an emergency call initiating request message including its own initial location information from a user equipment to an IP multimedia subsystem (IMS) core;   determining, by the IMS core, whether the initial location information included in the emergency call initiating request message is sufficient for determining an emergency center;   transmitting the emergency call initiating request message from the IMS core to a emergency center which is selected by IMS core on the basis of the initial location information, in case it is determined that the initial location information is sufficient for determining the emergency center; and   establishing an emergency call between the emergency center having received the emergency call initiating request message and the user equipment.   
     
     
         29 . The method according to  claim 28 , wherein the emergency call initiating request message includes at least one of an ID of the user equipment, emergency indicating information, capability of the user equipment, and a location ID in a network to which the user equipment belongs. 
     
     
         30 . The method according to  claim 28 , after the step of establishing the emergency call, further comprising the steps of:
 transmitting a location service request message requesting for updated location information of the user equipment from the emergency center to the location retrieval subsystem;   acquiring, by the location retrieval subsystem which accesses the user equipment, the updated location information of the user equipment in response to the location service request message; and   transmitting the updated location information from the location retrieval subsystem to the emergency center.   
     
     
         31 . A method for providing an emergency location service using a user equipment, the method comprising the steps of:
 transmitting a session connection request message including emergency indicator information to a core network;   accessing a location retrieval subsystem for acquiring current location information of the user equipment by measuring the current location of the user equipment in response to a request from the core network; and   establishing an emergency call in response to a session connection request from an emergency center which is selected by the core network on the basis of the current location information acquired by the location retrieval subsystem.   
     
     
         32 . The method according to  claim 31 , wherein the emergency center receives the session connection request message including the current location information from the core network. 
     
     
         33 . The method according to  claim 33 , wherein the core network is an IMS core. 
     
     
         34 . The method according to  claim 31 , wherein the location retrieval subsystem is a location retrieval function (LRF). 
     
     
         35 . A user equipment supporting an emergency location service, the user equipment comprising:
 a processor which transmits a session connectivity request message including emergency indicator information to a core network, which accesses a location retrieval subsystem for acquiring current location information of the user equipment by measuring current location of the user equipment in response to a request from the core network, and which performs a session connection to an emergency center in response to a session connection request from the emergency center which is selected by the core network on the basis of the current location information acquired by the location retrieval subsystem.   
     
     
         36 . The user equipment according to  claim 35 , wherein the core network is an IP multimedia subsystem (IMS) core. 
     
     
         37 . The user equipment according to  claim 35 , wherein the location retrieval subsystem is a location retrieval function (LRF).