Title of Invention	MOBILE TERMINAL AND MOBILE COMMUNICATION SYSTEM
Abstract	A mobile terminal UE according to the present invention performs, in an IP network, a normal communication between the mobile terminal and a normal communication terminal via a first call control apparatus S-CSCF#1, and an emergency-communication between the mobile terminal and an emergency-communication terminal via a second call control apparatus S-CSCF#2, including an emergency-communication session establishment processing unit 14 configured to perform an emergency-communication session establishment process between the mobile terminal UE and the emergency-communication terminal, without performing an emergency-communication location registration process for the mobile terminal in the second call control apparatus S-CSCF#2, when a normal-communication location registration process for the mobile terminal is completed in the first call control apparatus S-CSCF#1.

Title of Invention

MOBILE TERMINAL AND MOBILE COMMUNICATION SYSTEM

Abstract

A mobile terminal UE according to the present invention performs, in an IP network, a normal communication between the mobile terminal and a normal communication terminal via a first call control apparatus S-CSCF#1, and an emergency-communication between the mobile terminal and an emergency-communication terminal via a second call control apparatus S-CSCF#2, including an emergency-communication session establishment processing unit 14 configured to perform an emergency-communication session establishment process between the mobile terminal UE and the emergency-communication terminal, without performing an emergency-communication location registration process for the mobile terminal in the second call control apparatus S-CSCF#2, when a normal-communication location registration process for the mobile terminal is completed in the first call control apparatus S-CSCF#1.

Full Text	DESCRIPTION MOBILE TERMINAL AND MOBILE COMMUNICATION SYSTEM TECHNICAL FIELD The present invention relates to a mobile terminal and a mobile communication system, in which normal communications are performed between the mobile terminal and a normal communication terminal via a first call control apparatus and emergency-communications are performed between the mobile terminal and an emergency-communication terminal via a second call control apparatus, in an IP network including the first and second call control apparatus. BACKGROUND ART The 3rd Generation Partnership Project (3GPP), which is an international standardization organization for the third generation mobile communication system, has proposed a mobile communication system capable of performing emergency-communications between a mobile terminal and an emergency-communication terminal via an IP network (see Non-patent Document 1). As shown in Fig. 1, such mobile communication system includes an IP network configured of an IMS (IP Multimedia Subsystem) and an IP-CAN (GPRS/I-WLAN). Here, the IP-CAN is an acronym standing for "IP-Connectivity Access Network," GPRS is an acronym for "General Packet Radio Service," and l-WLAN is an acronym standing for "Interworking Wireless Access Network." In addition, the IMS is provided with a P-CSCF (Proxy-Call Sever Control Function), an S-CSCF (Serving-Call Server Control Function), an E-CSCF (Emergency-Call Server Control Function), and an HSS (Home Subscriber Server), while the IP-CAN (GPRS/I-WLAN) is provided with a function allowing the forwarding of IP data (SIP signals or VoIP packets). Here, the S-CSCF, the E-CSCF and the P-CSCF are SIP (Session Initiation Protocol) servers (call control apparatus) for controlling a normal-communication session between a mobile terminal UE and a normal communication terminal or an emergency-communication session between the mobile terminal UE and an emergency-communication terminal (PSAP: Public Safety Answering Point). Note that, the mobile terminal UE is configured to perform normal communications between the mobile terminal UE and a normal communication terminal (not shown in the drawings) via an S-CSCF#1 (first call control apparatus) and emergency-communications between the mobile terminal UE and the emergency-communication terminal PSAP, via an S-CSCF#2 (second call control apparatus) and an E-CSCF. By referring to Fig. 2, operations to start emergency-communications between the mobile terminal UE and PSAP in the above-described mobile communication system will be described. As shown in Fig. 2, in step S7001, the mobile terminal UE transmits, to the P-CSCF, an "Normal Registration Request" for requesting that the S-CSCF#1 perform a normal-communication location registration process (Normal Registration process) for the mobile terminal UE, by using normal-communication user identifiers (IMPI: an IP Multimedia Private Identifier and a Normal IMPU: IP Multimedia Public Identity). In step S7002, in response to the "Normal Registration Request," the normal-communication location registration process for the mobile terminal UE is performed between the mobile terminal UE and the S-CSCF#1 by referring to the HSS. Thereafter, in step S7003, the mobile terminal UE transmits, to the P-CSCF, an "Emergency Registration Request" for requesting that the S-CSCF#2 perform an emergency-communication location registration process (Emergency Registration process) for the mobile terminal UE, by using an emergency-communication user identifier (Emergency IMPU). In step S7004, in response to the "Emergency Registration Request," the emergency-communication location registration process for the mobile terminal UE is performed between the mobile terminal UE and the S-CSCF#2 by referring to the HSS. After the above emergency-communication location registration process is completed, in step S7005, the mobile terminal UE transmits, to the P-CSCF, an "Emergency SIP Invite" for requesting that an emergency-communication session establishment process be performed between the mobile terminal UE and the PSAP, by using the emergency-communication user identifier. In step S7006, the P-CSCF forwards the received "Emergency SIP Invite" to the E-CSCF. In step S7007, in response to the "Emergency SIP Invite," the emergency-communication session establishment process (Emergency Session Establishment process) is performed between the mobile terminal UE and the PSAP. The mobile terminal UE can perform emergency-communications between the mobile terminal UE and the PSAP by using the emergency-communication session establishment process set as described above. However, in the above-described mobile communication system, in order to allow emergency-communications from a mobile terminal in which a UICC is not provided (mobile terminal UE of a non-subscribed user), an emergency-communication location registration process, which is required only for performing emergency-communications, has to be performed, in addition to the normal-communication location registration process. In addition, the above-described mobile communication system requires to perform both of the normal-communication location registration process and the emergency-communication location registration process, since a normal-communication call control! apparatus (S-CSCF#1) is different from an emergency-communication call control apparatus (S-CSCF#2) provided to a command station of, for example, police, fire, Japan Coast Guard services or the like. Examples of the aforementioned example in which a normal-communication call control apparatus (S-CSCF#1) is different from an emergency-communication call control apparatus (S-CSCF#2) includes an example in which a mobile terminal UE performs an emergency-communication session establishment process from a network outside its home network. Accordingly, in the above-described communication system, even when a normal-communication location registration process for a certain mobile terminal UE is completed, an emergency-communication registration process for the mobile terminal UE has to be additionally performed. Thus, the communication system has a problem that time until starting emergency-communications is longer. Non-patent Document 1: 3GPP TS23.167 Ver.7.0.0 DISCLOSURE OF THE INVENTION The present invention has been made in view of the foregoing problem. Accordingly, an object of the present invention is to provide a mobile terminal and a mobile communication system, which can shorten a time until starting an emergency-communication in an IF3 network. A first aspect of the invention is summarized as a mobile terminal that performs a normal communication between the mobile terminal and a normal communication terminal via a first call control apparatus, and an emergency-communication between the mobile terminal and an emergency-communication terminal via a second call control apparatus, in an IP network including the first call control apparatus and the second call control apparatus. The mobile terminal includes: an emergency-communication session establishment processing unit configured to perform an emergency-communication session establishment process between the mobile terminal and the emergency-communication terminal, without performing an emergency-communication location registration process for the mobile terminal in the second call control apparatus, when a normal-communication location registration process for the mobile terminal is completed in the first call control apparatus. In the first aspect of the invention, the emergency-communication session establishment processing unit may be configured to perform the emergency-communication session establishment process between the mobile terminal and the emergency-communication terminal, without performing the emergency-communication location registration process for the mobile terminal in the second call control apparatus, when the normal-communication location registration process for the mobile terminal is completed in the first call control apparatus and when a determination is made that not both of the normal-communication location registration process for the mobile terminal and the emergency-communication location registration process for the mobile terminal need to be performed in performing the emergency communication in the IP network. In the first aspect of the invention, the emergency-communication session establishment processing unit may be configured to make the determination based on information notified from the IP network in performing the normal-communication location registration process for the mobile terminal. The first aspect of the invention may be configured to further include an emergency-communication location registration processing unit configured to transmit an emergency-communication location registration request for requesting that the second call control apparatus perform the emergency-communication location registration process for the mobile terminal, when the normal-communication location registration process for the mobile terminal is not completed in the first call control apparatus, and the emergency-communication session establishment processing unit may be configured to perform the emergency-communication session establishment process between the mobile terminal and the emergency-communication terminal, without performing the normal-communication location registration process for the mobile terminal in the first call control apparatus, when the emergency-communication location registration process for the mobile terminal is completed in the second call control apparatus in response to the emergency-communication location registration request. The first aspect of the invention may be configured to include an emergency-communication location registration processing unit configured to transmit an emergency-communication location registration request for requesting that the second call control apparatus perform the emergency-communication location registration process for the mobile terminal, when a UICC is not provided in the mobile terminal, and the emergency-communication session establishment processing unit may be configured to perform, the emergency-communication session establishment process between the mobile terminal and the emergency-communication terminal without performing the normal-communication location registration process for the mobile terminal in the first call control apparatus, when the emergency-communication location registration process for the mobile terminal is completed in the second call control apparatus in response to the emergency-communication location registration request. In the first aspect of the invention, the emergency-communication session establishment processing unit may be configured to make the determination based on information notified from the IP network in performing a location registration process in the IP network. A second aspect of the invention is summarized as a mobile communication system in which a mobile terminal performs a normal communication between the mobile terminal and a normal communication terminal via a first call control apparatus, and performs an emergency-communication between the mobile terminal and an emergency-communication terminal via a second call control apparatus, the normal communication and the emergency-communication being performed via an IP network including the first call control apparatus and the second call control apparatus. The mobile terminal is configured to transmit an emergency-communication session establishment process request for requesting that an emergency-communication session establishment process be performed between the mobile terminal and the emergency-communication terminal, when a normal-communication location registration process for the mobile terminal is completed in the first call control apparatus, and the IP network is configured to perform the emergency-communication session establishment process between the mobile terminal and the emergency-communication terminal, when the emergency-communication location registration process for the mobile terminal is not performed in the second call control apparatus and when the normal-communication location registration process for the mobile terminal is completed in the first call control apparatus. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an overall configurational view of a general mobile communication system; Fig. 2 is a sequential view for illustrating operations of a mobile communication system according to a conventional art; Fig. 3 is a functional block diagram of a mobile terminal according to a first embodiment of the present invention; Fig. 4 is a flowchart showing overall operations of a mobile communication system according to the first embodiment of the present invention; Fig. 5 is a flowchart at a procedure 1 in the overall operations of the mobile communication system according to the first embodiment of the present invention; Fig. 6 is a flowchart at a procedure 2 in the overall operations of the mobile communication system according to the first embodiment of the present invention; Fig. 7 is a sequential view for illustrating the operations of the mobile communication system according to the first embodiment of the present invention; Fig. 8 is a sequential view for illustrating the operations of the mobile communication system according to the first embodiment of the present invention; Fig. 9 is a sequential view for illustrating the operations of the mobile communication system according to the first embodiment of the present invention; Fig. 10 is a sequential view for illustrating the operations of the mobile communication system according to the first embodiment of the present invention; Fig. 11 is a flowchart showing the overall operations of the mobile communication system according to the first embodiment of the present invention; Fig. 12 is a flowchart at procedure 1 in the overall operations of the mobile communication system according to the first embodiment of the present invention; Fig. 13 is a sequential view for illustrating the operations of the mobile communication system according to the first embodiment of the present invention; Fig. 14 is a sequential view for illustrating the operations of the mobile communication system according to the first embodiment of the present invention; Fig. 15 is a sequential view for illustrating the operations of the mobile communication system according to the first embodiment of the present invention; and Fig. 16 is a sequential view for illustrating the operations of the mobile communication system according to the first embodiment of the present invention. BEST MODES FOR CARRYING OUT THE INVENTION (Configuration of a mobile communication system according to a first embodiment of the present invention) As shown in Fig. 1, a mobile communication system according to the present embodiment is configured so that a mobile terminal LIE perform normal communications between the mobile terminal UE and a normal communication terminal via the S-CSCF#1; and emergency-communications between the mobile terminal UE and a PSAP (emergency-communication terminal) via the S-CSCF#2 and the E-CSCF, in the IP network including an S-CSCF#1 (first call control apparatus), an S-CSCF#2 (second call control apparatus), an E-CSCF, and a P-CSCF. Here, as will be described later, such IP network is configured so that an emergency-communication session establishment process (Emergency Session Establishment process) between the mobile terminal UE and the PSAP would be performed even when an emergency-communication location registration process (Emergency Registration process ) for the mobile terminal UE is not performed in the S-CSCS#2, as long as a normal-communication location registration process (Normal Registration process ) for the mobile terminal UE is completed in the S-CSCS#1. Referring to Fig. 3, the configuration of the mobile terminal UE according to the first embodiment of the present invention will be described. The mobile terminal UE according to the present embodiment is configured so as to perform normal communications between the mobile terminal UE and a normal communication terminal via the S-CSCF#1; and emergency-communications between the mobile terminal UE and the PSAP via the S-CSCF#2 and the E-CSCF in the above-described IP network. As shown in Fig. 3, the mobile terminal UE according to the present embodiment is provide with a UICC detecting unit 11, a Normal Registration processing unit 12, an Emergency Registration processing unit 13, and an Emergency Session Establishment processing unit 14. The UICC detecting unit 11 is configured to detect whether a UICC (Universal Integrated Circuit Card) is provided in the mobile terminal UE. The Normal Registration processing unit 12 is configured to perform a normal-communication location registration process (Normal Registration process) for the mobile terminal UE in the S-CSCF#1 when a predetermined condition, for example, at power-on of the mobile terminal UE is satisfied. Specifically, in order to perform the normal-communication location registration process , the Normal Registration processing unit 12 is configured to transmit, to the P-CSCF, a normal registration request for requesting that a normal-communication location registration process be performed by using normal-communication user identifiers. The Emergency Registration processing unit 13 is configured to perform an emergency-communication location registration process (Emergency Registration process) for the mobile terminal UE in the S-CSCF#2 when a predetermined condition is satisfied. Specifically, the Emergency Registration processing unit 13 is configured to transmit, to the P-CSCF, an emergency registration request for requesting that an emergency-communication location registration process be performed by using emergency-communication user identifiers, in order to perform the emergency-communication location registration process. For example, when a UICC is not provided in the mobile terminal UE or a normal-communication location registration process for the mobile terminal UE is not completed in the S-CSCF#1, the Emergency Registration processing unit 13 is configured to transmit, to the P-CSCF, an emergency registration request for requesting that the S-CSCF#2 perform emergency-communication location registration process for the mobile terminal UE by using emergency-communication user identifiers. When the predetermined condition is satisfied, the Emergency Session Establishment processing unit 14 is configured to perform an emergency-communication session establishment process (Emergency Session Establishment process) for performing emergency-communications between the mobile terminal UE and the PSAP via the S-CSCF#2 and the E-CSCF. Specifically, in order to perform such emergency-communication session establishment process, the Emergency Session Establishment processing unit 14 is configured to transmit an emergency-communication session establishment process request (Emergency SIP Invite) for requesting that an emergency-communication session establishment process be performed between the mobile terminal UE and the PSAP. For example, the Emergency Session Establishment processing unit 14 is configured to perform an emergency-communication session establishment process between the mobile terminal UE and the PSAP without performing an emergency-communication location registration process for the mobile terminal UE in the S-CSCF#2, when a normal-communication location registration process for the mobile terminal UE is completed in the S-CSCF#1, and when it is determined that not both of the normal-communication for the mobile terminal UE and emergency-communication location registration process for the mobile terminal UE need to be performed in order to perform the emergency-communications in the above-described IP network. Here, the Emergency Session Establishment processing unit 14 may be configured to make the above-described determination based on information (determination key, for example) notified from the IP network in performing the normal-communication location registration process for the mobile terminal UE. In addition, the Emergency Session Establishment processing unit 14 is configured to perform an emergency-communication session establishment process between the mobile terminal UE and the PSAP without performing a normal-communication location registration process for the mobile terminal UE in the S-CSCF#1, when an emergency-communication location registration process for the mobile terminal UE is completed in the S-CSCF #1 in response to the above-mentioned emergency registration request. (Operations of the mobile communication system according to the first embodiment of the present invention) Hereinafter, operations of the mobile communication system according to the present embodiment will be described by referring to Figs. 4 to 10. Specifically, the operations of the mobile terminal UE according to the present embodiment will be described by referring to Figs. 4 to 6 and the operations of the mobile communication system according to the present embodiment will be described by referring to Figs. 7 to 10. As shown in Fig. 4, in step S101, an emergency call to be transmitted from the mobile terminal UE to the PSAP occurs. In step S102, the mobile terminal UE determines whether a UICC is provided in the mobile terminal UE. When it is determined that a UICC is provided in the mobile terminal UE, the present operation proceeds to step S103 to execute the procedure 1 shown in Fig. 5. When it is determined that a UICC is not provided in the mobile terminal UE, the present operation proceeds to step S104 to execute the procedure 2 shown in Fig. 6. Firstly, with reference to Fig. 5, operations of the procedure 1 performed by the mobile terminal UE will be described. As shown in Fig. 5, in step S201, the mobile terminal UE determines whether a normal-communication location registration process for the mobile terminal UE is completed in the S-CSCF#1. When it is determined that the normal-communication location registration process is completed, the present operation proceeds to step S202. When it is determined that the normal-communication location registration process is not completed, the procedure 2 shown in Fig. 6 is executed in the present operation. In step S202, the mobile terminal UE determines whether an emergency-communication location registration process for the mobile terminal UE needs to be performed in the S-CSCF#2, based on information (determination key, for example) notified from the IP network in performing the normal-communication location registration process for the mobile terminal UE. In other words, the mobile terminal UE determines whether both of the normal-communication for the mobile terminal UE and the emergency-communication location registration process for the mobile terminal UE need to be performed in order to perform emergency-communications in the IP network. When it is determined that both of the normal-communication location registration process and the emergency-communication location registration process need to be performed, the present operation proceeds to step S203. When it-is determined that not both of the normal-communication location registration process and the emergency-communication location registration process need to be performed, the present operation proceeds to step S105 in Fig. 4. In step S203, the mobile terminal UE transmits, to the P-CSCF, an emergency registration request for requesting that an emergency-communication location registration process be performed by using emergency-communication user identifiers, in order to perform the emergency-communication location registration process . In step S204, the mobile terminal UE performs the emergency registration between the mobile terminal UE and the S-CSCF#2. Thereafter, the present operation proceeds to step S105 in Fig. 4. Secondly, with referring to Fig. 6, operations of the procedure 2 performed by the mobile terminal UE will be described. As shown in Fig. 6, in step S301, the mobile terminal UE transmits, to the P-CSCF, an emergency registration request for requesting that the S-CSCF#2 perform an emergency-communication location registration process for the mobile terminal UE by using emergency-communication user identifiers. In step S302, the mobile terminal UE determines whether a normal-communication location registration process for the mobile terminal UE needs to be performed in the S-CSCF#1, based on an instruction included in a response from the P-CSCF for the emergency registration request. In other words, the mobile terminal UE determines whether a normal-communication location registration process for the mobile terminal UE needs to be performed before an emergency-communication location registration process for the mobile terminal UE is performed in the IP network. When it is determined that the normal-communication location registration process needs to be performed, the present operation proceeds to step S303. When it is determined that the normal-communication location registration process does not need to be performed, the present operation proceeds to step S305. In step S303, the mobile terminal UE transmits, to the P-CSCF, a normal registration request for requesting that a normal-communication location registration process be performed by using normal-communication user identifiers, in order to perform such normal-communication location registration process. In step S304, the mobile terminal UE performs a normal-communication location registration process for the mobile terminal UE between the mobile terminal UE and the S-CSCF#1. Thereafter, the present operation proceeds to step S202 in Fig. 5. Note that, when a UICC is not provided in the mobile terminal UE, the mobile terminal UE cannot perform the normal-communication location registration process by using a normal-communication user identifier and thus cannot perform emergency-communications between the mobile terminal UE and the PSAP. In step S305, the mobile terminal UE performs an emergency-communication location registration process for the mobile terminal UE between the mobile terminal UE and the S-CSCF#2. Thereafter, the present operation proceeds to step S105 in Fig. 4. In step S105, the mobile terminal UE transmits, to the P-CSCF, emergency-communication session establishment process request (Emergency SIP Invite) for requesting that an emergency-communication session establishment process be performed between the mobile terminal UE and the PSAP, in order to perform the emergency-communication session establishment process between the mobile terminal UE and the PSAP. In step S106, the mobile terminal UE performs the emergency-communication session establishment process between the mobile terminal UE and the PSAP, the emergency-communication session establishment process being used for emergency-communications. Next, operations (in four cases) to start emergency-communications between the mobile terminal UE and a PSAP in the mobile communication system according to the present embodiment will be described by referring to Figs. 7 to 10. Firstly, the operations of the mobile communication system according to a first case of the present embodiment will be described by referring to Fig. 7. In the first case, as shown in Fig. 7, the mobile terminal UE determines: that a UICC is provided in the mobile terminal UE in step S1001; that a normal-communication location registration process for the mobile terminal UE is completed in the S-CSCF#1 in step S1002; and that, in step S2003, not both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed, in performing the emergency-communications in the IP network. In such case, in step S1004, the mobile terminal UE transmits, to the P-CSCF, an emergency-communication session establishment process request for requesting that an emergency-communication session establishment process (Emergency Session Establishment process) be performed between the mobile terminal UE and the PSAP by using normal-communication user identifiers, without performing an emergency-communication location registration process for the mobile terminal UE in the S-CSCF#2. In step S1005, the P-CSCF forwards the received emergency-communication session establishment process request to the E-CSCF. In step S1006, the E-CSCF forwards the received emergency-communication session establishment process request to the PSAP. In step S1007, an emergency-communication location registration process for the mobile terminal UE is not performed in the S-CSCF#2. Nonetheless, the emergency-communication session establishment process between the mobile terminal UE and the PSAP is performed, since the normal-communication location registration process for the mobile terminal UE is completed in the S-CSCF#1. By using the emergency-communication session establishment process set as described above, the mobile terminal UE can perform emergency-communications between the mobile terminal UE and the PSAP. Secondly, the operations of the mobile communication system according to a second case of the present embodiment will be described by referring to Fig. 8. In the second case, as shown in Fig. 8, the mobile terminal UE determines: that a UICC is provided in the mobile terminal UE in step S2001; that a normal-communication location registration process for the mobile terminal UE is completed in the S-CSCF in step S2002; and that, in step S2003, both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed in order to perform emergency-communications in the IP network. In step S2004, the mobile terminal UE transmits, to the P-CSCF, an emergency registration request for requesting that the S-CSCF#2 perform an emergency-communication location registration process for the mobile terminal UE by using emergency-communication user identifiers. In step S2005, in response to the emergency registration request, an emergency-communication location registration process for the mobile terminal UE is performed between the mobile terminal UE and the S-CSCF#2, by referring to the HSS. In step S2006, the mobile terminal UE transmits, to the P-CSCF, an emergency-communication session establishment process request (Emergency SIP Invite) for requesting that an emergency-communication session establishment process be performed between the mobile terminal UE and the PSAP by using emergency-communication user identifiers, after the emergency-communication location registration process is completed. In step S2007, the P-CSCF forwards the received Emergency SIP Invite to the E-CSCF. In step S2008, the E-CSCF forwards the received Emergency-communication session establishment process request to the PSAP. In step S2009, in response to the Emergency SIP Invite, the emergency-communication session establishment process between the mobile terminal UE and the PSAP is performed between the mobile terminal UE and the PSAP. By using the emergency-communication session establishment process set as described above, the mobile terminal UE can perform emergency-communications between the mobile terminal UE and the PSAP. Thirdly, the operations of the mobile communication system according to a third case of the present embodiment will be described while referring to Fig. 9. In the third case, as shown in Fig. 9, the mobile terminal UE determines: that a UICC is provided in the mobile terminal UE in step S3001; and that a normal-communication location registration process for the mobile terminal UE is not completed in the S-CSCF#1 in step S3002. In step S3003, the mobile terminal UE transmits, to the P-CSCF, an emergency registration request for requesting that the S-CSCF#2 perform an emergency-communication location registration process for the mobile terminal UE by using emergency-communication user identifiers. In step S3004, in response to the emergency registration request, the P-CSCF transmits a response including an instruction indicating whether or not a normal-communication location registration process for the mobile terminal UE needs to be performed before performing an emergency-communication location registration process for the mobile terminal UE in the IP network. In step S3005, the mobile terminal UE determines, based on the response from the P-CSCF, whether or not a normal-communication location registration process for the mobile terminal UE needs to be performed before performing an emergency-communication location registration process for the mobile terminal UE in the IP network. Here, in the third case, it is determined that a normal-communication location registration process for the mobile terminal UE needs to be performed before an emergency-communication location registration process for the mobile terminal UE is performed in the IP network. In step S3006, the mobile terminal UE transmits, to the P-CSCF, a normal registration request for requesting that the S-CSCF#1 perform the normal-communication location registration process (Normal Registration process) for the mobile terminal UE by using normal-communication user identifiers. In step S3007, in response to the normal registration request, the normal-communication location registration process for the mobile terminal UE is performed between the mobile terminal UE and the S-CSCF#1 by referring to the HSS. In step S3008, the mobile terminal UE determines whether an emergency-communication location registration process for the mobile terminal UE needs to be performed in the S-CSCF#2, based on information (determination key, for example) notified from the IP network in the normal-communication location registration process for the mobile terminal UE performed in step S3007. That is, the mobile terminal UE determines whether both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed, in performing emergency-communications in the IP network. Here, in the third case, assume that it is determined that not both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed, in performing the emergency-communications. In step S3009, the mobile terminal UE transmits, to the P-CSCF, an Emergency-communication session establishment process request for requesting that an emergency-communication session establishment process be performed between the mobile terminal UE and the PSAP by using normal-communication user identifiers without performing an emergency-communication location registration process for the mobile terminal UE in the S-CSCF#2. In step S3010, the P-CSCF forwards the received Emergency-communication session establishment process request to the E-CSCF. In step S3011, the E-CSCF forwards the received Emergency-communication session establishment process request to the PSAP. In step S3012, an emergency-communication location registration process for the mobile terminal UE is not performed in the S-CSCF#2. Nonetheless, an emergency-communication session establishment process between the mobile terminal UE and the PSAP is performed, since in the above-described IP network, the normal-communication location registration process for the mobile terminal UE is completed in the S-CSCF#1. By using the emergency-communication session establishment process set as described above, the mobile terminal UE can perform emergency-communications between the mobile terminal UE and the PSAP. Fourthly, the operations of the mobile communication system according to a fourth case of the present embodiment will be described while referring to Fig. 10. In the fourth case, as shown in Fig. 10, the mobile terminal UE determines: that a UICC is provided in the mobile terminal UE in step S4001; and that a normal-communication location registration process for the mobile terminal UE is not completed in the S-CSCF#1, in step S4002. Alternatively, in step S4001 of the fourth case, the mobile terminal UE may determine that a UICC is not provided in the mobile terminal UE, as shown in Fig. 10. In either case, in step S4003, the mobile terminal UE transmits, to the P-CSCF, an emergency registration request for requesting that the S-CSCF#2 perform an emergency-communication location registration process for the mobile terminal UE by using emergency-communication user identifiers. In step S4004, in response to the emergency registration request, the P-CSCF determines that a normal-communication location registration process for the mobile terminal UE does not need to be performed before the emergency-communication location registration process for the mobile terminal UE is performed in the IP network. Then, the emergency-communication location registration process for the mobile terminal UE is performed between the mobile terminal UE and the S-CSCF#2 by referring to the HSS. In step S4005, the mobile terminal UE transmits, to the P-CSCF, an emergency-communication session establishment process request (Emergency SIP Invite) for requesting that an emergency-communication session establishment process be performed between the mobile terminal UE and the PSAP by using emergency-communication user identifiers after the above-described emergency-communication location registration process is completed. In step S4006, the P-CSCF forwards the received Emergency SIP Invite to the E-CSCF. In step S4007, the E-CSCF forwards the received emergency-communication session establishment process request to the PSAP. In step S4008, in response to the Emergency SIP Invite, the emergency-communication session establishment process between the mobile terminal UE and the PSAP is performed between the mobile terminal UE and the PSAP by referring to the HSS, although a normal-communication location registration process for the mobile terminal UE is not performed in the S-CSCF#1. By using the emergency-communication session establishment process set as described above, the mobile terminal UE can perform emergency-communications between the mobile terminal UE and the PSAP. (Advantageous effects of the mobile communication system according to the first embodiment of the present invention) In the mobile terminal and the mobile communication system according to the present embodiment, an emergency-communication session establishment process would be performed between the mobile terminal UE and the PSAP without performing an emergency-communication location registration process for the mobile terminal UE in the S-CSCF#2, when a normal-communication location registration process for the mobile terminal is completed in the S-CSCF#1 and it is determined that not both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed, in performing the emergency-communications in the IP network. Accordingly, time until starting emergency-communications in an IP network can be shortened. In addition, in the mobile terminal and the mobile communication system according to the present embodiment, when it is determined that both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed in performing the emergency-communications in the IP network and when a normal-communication location registration process for the mobile terminal UE is completed in the S-CSCF#1, an emergency-communication session establishment process is performed between the mobile terminal UE and the PSAP after an emergency-communication location registration process for the mobile terminal UE is performed in the S-CSCF#2. Accordingly, the mobile terminal and the mobile communication system according to the present embodiment are applicable to a conventional IP network in which both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed, in performing emergency-communications. Also, the mobile terminal and the mobile communication system according to the present embodiment are applicable to the IP network according to the present invention in which not both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed in performing emergency-communications. In addition, when a UICC is not provided in the mobile terminal UE, or when an emergency-communication location registration process for the mobile terminal UE is completed in the 3-CSCF#2 in response to an emergency registration request transmitted by the mobile terminal UE and when a normal-communication location registration process for the mobile terminal UE is not completed in the S-CSCF#1, the mobile terminal and mobile communication system according to the present embodiment are configured that an emergency-communication session establishment process would be performed between the mobile terminal UE and the PSAP without performing a normal-communication location registration process for the mobile terminal UE in the S-CSCF#1. Accordingly, time until starting emergency-communications in the IP network can be shortened. (A mobile communication system according to a second embodiment of the present invention) Referring to Figs. 11 to 16, a mobile communication system according to a second embodiment of the present invention will be described. In the present embodiment, the above-described S-CSCF#1 (first call control apparatus) and the S-CSCF#2 (second call control apparatus) are provided in the same apparatus (S-CSCF). Specifically, operations of the mobile terminal UE according to the present embodiment will be described by referring to Figs. 11 and 12, and operations of the mobile communication system according to the present embodiment will be described by referring to Figs. 13 to 16. As shown in Fig. 11, in step S501, an emergency call to be performed from the mobile terminal UE to the PSAP occurs. In step S102, the mobile terminal UE determines whether a UICC is provided in the mobile terminal UE. When it is determined that a UICC is provided in the mobile terminal UE, the present operation proceeds to step S503 to execute the procedure 1. When it is determined that a UICC is not provided in the mobile terminal UE, the present operation proceeds to step S504. Here, by referring to Fig. 12, operations of the procedure 1 performed by the mobile terminal UE will be described. As shown in Fig. 12, in step S601, the mobile terminal UE determines whether or not the mobile terminal UE is located in a Home network or in a visited network, by using information acquired from an IP network in performing, for example, a GPRS (General Packet Radio Service) attach process (registration process for GPRS) or l-WLAN attach process (registration process for l-WLAN), based on information notified from the IP network in performing a registration process in the IP network. When it is determined that the mobile terminal UE is located in the Home network, the present operation proceeds to step S602. When it is determined that the mobile terminal UE is located in the visited network, the present operation proceeds to step S603. In step S602, the mobile terminal UE determines whether a normal-communication location registration process for the mobile terminal UE is completed in the S-CSCF#1. When it is determined that the normal-communication location registration process for the mobile terminal UE is completed, the present operation proceeds to step S504 in Fig. 11. When it is determined that the normal-communication location registration process for the mobile terminal UE is not completed, the present operation proceeds to step S603. In step S603, the mobile terminal UE transmits, to the P-CSCF, an emergency registration request for requesting that an emergency-communication location registration process be performed by using emergency-communication user identifiers, in order to perform the emergency-communication location registration process. In step S604, after the mobile terminal UE performs the emergency registration between the mobile terminal UE and the S-CSCF#2, the present operation proceeds to step S504 in Fig. 11. Specifically, the mobile terminal UE determines whether an emergency-communication location registration process for the mobile terminal UE needs to be performed in the S-CSCF#2 based on information (determination key, for example) notified from the IP network in performing the registration process for the mobile terminal UE in the IP network. In other words, the mobile terminal UE determines whether both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed in performing the emergency-communications in the IP network. Specifically, when it is determined that the mobile terminal UE is located in the Home network, based on the information (determination key, for example) notified from the IP network in the registration process for the mobile terminal UE in the IP network, the mobile terminal UE determines that not both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed in performing the emergency-communications in the IP network. On the other hand, when it is determined that the mobile terminal UE is not located in the Home network (that is, located in the visited network), based on the information (for example, determination key) notified from the IP network in the registration process for the mobile terminal UE in the IP network, the mobile terminal UE determines that both of the normal-communication location registration process and the emergency-communication location registration process for the mobile terminal UE need to be performed in performing the emergency-communications in the IP network. In step S504, the mobile terminal UE transmits, to the P-CSCF, an emergency-communication session establishment process request (Emergency SIP Invite) for requesting that an emergency-communication session establishment process be performed between the mobile terminal UE and the PSAP, in order to perform an emergency-communication session establishment process used for emergency-communications between the mobile terminal UE and the PSAP. In step S505, the mobile terminal UE performs the emergency-communication session establishment process used for emergency-communications between the mobile terminal UE and the PSAP. Next, operations (in four cases) to start emergency-communications between the mobile terminal UE and the PSAP in the mobile communication system according to the present embodiment will be described by referring to Figs. 13 to 16. Firstly, the operations of the mobile communication system according to a first case of the present embodiment will be described by referring to Fig. 13. In the first case, as shown in Fig. 13, the mobile terminal UE determines: that a UICC is provided in the mobile terminal UE in step S5001; that the mobile terminal UE is located in the Home network in step S5002; and that a normal-communication location registration process for the mobile terminal UE is completed in step S5003. In such case, in step S5004, the mobile terminal UE transmits, to the P-CSCF, an emergency-communication session establishment process request (Emergency SIP Invite) for requesting that an emergency-communication session establishment process (Emergency Session Establishment process) be performed between the mobile terminal UE and the PSAP by using normal-communication user identifiers without performing an emergency-communication location registration process for the mobile terminal UE in the S-CSCF#2. In step S5005, the P-CSCF forwards the received Emergency-communication session establishment process request to the E-CSCF. In step S5006, the E-CSCF forwards the received Emergency-communication session establishment process request to the PSAP. In step S5007, an emergency-communication location registration process for the mobile terminal UE is not performed in the S-CSCF#2 in the above-described IP network. Nonetheless, an emergency-communication session establishment process between the mobile terminal UE and the PSAP is performed, since the normal-communication location registration process for the mobile terminal UE is completed in the S-CSCF#1. By using the emergency-communication session establishment process set as described above, the mobile terminal UE can perform emergency-communications between the mobile terminal UE and the PSAP. Secondly, the operations of the mobile communication system according to a second case of the present embodiment will be described by referring to Fig. 14. In the second case, as shown in Fig. 14, the mobile terminal UE determines: that a UICC is provided in the mobile terminal UE in step S6001; that the mobile terminal UE is located in the Home network in step S6002; and that a normal-communication location registration process for the mobile terminal UE is not completed in step S6003. In step S6004, the mobile terminal UE transmits, to the P-CSCF, an emergency registration request for requesting that the S-CSCF#2 perform an emergency-communication location registration process for the mobile terminal UE by using emergency-communication user identifiers. In step S6005, in response to the emergency registration request, the emergency-communication location registration process for the mobile terminal UE is performed between the mobile terminal UE and the S-CSCF#2 by referring to the HSS. In step S6006, the mobile terminal UE transmits, to the P-CSCF, an emergency-communication session establishment process request (Emergency SIP Invite) for requesting that an emergency-communication session establishment process be performed between the mobile terminal UE and the PSAP by using emergency-communication user identifier, after the emergency-communication location registration process is completed. In step S6007, the P-CSCF forwards the received Emergency SIP Invite to the E-CSCF. In step S6008, the E-CSCF forwards the received Emergency-communication session establishment process request to the PSAP. In step S6009, in response to the Emergency SIP Invite, an emergency-communication session establishment process between the mobile terminal UE and the PSAP is performed between the mobile terminal UE and the PSAP. By using the emergency-communication session establishment process set as described above, the mobile terminal UE can perform emergency-communications between the mobile terminal UE and the PSAP. Thirdly, the operations of the mobile communication system according to a third case of the present embodiment will be described by referring to Fig. 15. In the third case, as shown in Fig. 15, the mobile terminal UE determines: that a UICC is provided in the mobile terminal UE in step S7001; and that the mobile terminal UE is not located in the Home network in step S7002. In step S7003, the mobile terminal UE transmits, to the P-CSCF, an emergency registration request for requesting that the S-CSCF#2 perform an emergency-communication location registration process for the mobile terminal UE by using emergency-communication user identifiers. In step S7004, in response to the emergency registration request, an emergency-communication location registration process for the mobile terminal UE is performed between the mobile terminal UE and S-CSCF#2 by referring to the HSS. In step S7005, the mobile terminal UE transmits, to the P-CSCF, an Emergency-communication session establishment process request for requesting that an emergency-communication session establishment process be performed between the mobile terminal UE and the PSAP by using a user normal-communication user identifier without performing an emergency-communication location registration process for the mobile terminal UE in the S-CSCF#2. In step S7006, the P-CSCF forwards the received Emergency-communication session establishment process request to the E-CSCF. In step S7007, the E-CSCF forwards the received Emergency-communication session establishment process request to the PSAP. In step S7008, in the above-described IP network, an emergency-communication location registration process for the mobile terminal UE is not performed in the S-CSCF#2. Nonetheless, an emergency-communication session establishment process between the mobile terminal UE and the PSAP is performed, since the normal-communication location registration process for the mobile terminal UE is completed in the S-CSCF#1. By using the emergency-communication session establishment process set as described above, the mobile terminal UE can perform emergency-communications between the mobile terminal UE and the PSAP. Fourthly, the operations of the mobile communication system according to a fourth case of the present embodiment will be described by referring to Fig. 16. In the fourth case, as shown in Fig. 16, the mobile terminal UE determines, in step S8001, that a UICC is not provided in the mobile terminal UE. In step S8002, the mobile terminal UE transmits, to the P-CSCF, an emergency-communication session establishment process request (Emergency SIP Invite) for requesting that an emergency-communication session establishment process be performed between the mobile terminal UE and the PSAP by using emergency-communication user identifiers. In step S8003, the P-CSCF forwards the received Emergency SIP Invite to the E-CSCF. In step S8004, the E-CSCF forwards the received Emergency-communication session establishment process request to the PSAP. In step S8005, a normal-communication location registration process for the mobile terminal UE is not performed in the S-CSCF#1. Nonetheless, an emergency-communication session establishment process between the mobile terminal UE and the PSAP is performed between the mobile terminal UE and the PSAP by referring to the HSS in response to the Emergency SIP Invite. By using the emergency-communication session establishment process set as described above, the mobile terminal UE can perform emergency-communications. As has been described above, the present invention has been described by using the above-described embodiments. However, it is obvious for those who are in the art that the present invention is not limited to the embodiments described herein. The present invention can be amended and be implemented as modified embodiments without departing from the contents and scope of the present invention, which are defined by the description of claims. Accordingly, the description of the present invention is intended to show an illustrative example, and not intended to limit the present invention. INDUSTRIAL APPLICABILITY As described above, the present invention can provide a mobile terminal and a mobile communication system, which can shorten a time until starting an emergency-communication in an IP network. CLAIMS [1] A mobile terminal that performs a normal communication between the mobile terminal and a normal communication terminal via a first call control apparatus, and an emergency-communication between the mobile terminal and an emergency-communication terminal via a second call control apparatus, in an IP network including the first call control apparatus and the second call control apparatus, the mobile terminal comprising: an emergency-communication session establishment processing unit configured to perform an emergency-communication session establishment process between the mobile terminal and the emergency-communication terminal, without performing an emergency-communication location registration process for the mobile terminal in the second call control apparatus, when a normal-communication location registration process for the mobile terminal is completed in the first call control apparatus. [2] The mobile terminal according to claim 1, wherein the emergency-communication session establishment processing unit is configured to perform the emergency-communication session establishment process between the mobile terminal and the emergency-communication terminal, without performing the emergency-communication location registration process for the mobile terminal in the second call control apparatus, when the normal-communication location registration process for the mobile terminal is completed in the first call control apparatus and when a determination is made that not both of the normal-communication location registration process for the mobile terminal and the emergency-communication location registration process for the mobile terminal need to be performed in performing the emergency communication in the IP network. [3] The mobile terminal according to claim 2, wherein the emergency-communication session establishment processing unit is configured to make the determination based on information notified from the IP network in performing the normal-communication location registration process for the mobile terminal. [4] The mobile terminal according to claim 1, comprising: an emergency-communication location registration processing unit configured to transmit an emergency-communication location registration request for requesting that the second call control apparatus perform the emergency-communication location registration process for the mobile terminal, when the normal-communication location registration process for the mobile terminal is not completed in the first call control apparatus, wherein the emergency-communication session establishment processing unit is configured to perform the emergency-communication session establishment process between the mobile terminal and the emergency-communication terminal, without performing the normal-communication location registration process for the mobile terminal in the first call control apparatus, when the emergency-communication location registration process for the mobile terminal is completed in the second call control apparatus in response to the emergency-communication location registration request. [5] The mobile terminal according to claim 1, comprising: an emergency-communication location registration processing unit configured to transmit an emergency-communication location registration request for requesting that the second call control apparatus perform the emergency-communication location registration process for the mobile terminal, when a UICC is not provided in the mobile terminal, wherein the emergency-communication session establishment processing unit is configured to perform, the emergency-communication session establishment process between the mobile terminal and the emergency-communication terminal without performing the normal-communication location registration process for the mobile terminal in the first call control apparatus, when the emergency-communication location registration process for the mobile terminal is completed in the second call control apparatus in response to the emergency-communication location registration request. [6] The mobile terminal according to claim 2, wherein the emergency-communication session establishment processing unit is configured to make the determination based on information notified from the IP network in performing a location registration process in the IP network. [7] A mobile communication system in which a mobile terminal performs a normal communication between the mobile terminal and a normal communication terminal via a first call control apparatus, and performs an emergency-communication between the mobile terminal and an emergency-communication terminal via a second call control apparatus, the normal communication and the emergency-communication being performed via an IP network including the first call control apparatus and the second call control apparatus, wherein the mobile terminal is configured to transmit an emergency-communication session establishment process request for requesting that an emergency-communication session establishment process be performed between the mobile terminal and the emergency-communication terminal, when a normal-communication location registration process for the mobile terminal is completed in the first call control apparatus, and the IP network is configured to perform the emergency-communication session establishment process between the mobile terminal and the emergency-communication terminal, when the emergency-communication location registration process for the mobile terminal is not performed in the second call control apparatus and when the normal-communication location registration process for the mobile terminal is completed in the first call control apparatus. A mobile terminal UE according to the present invention performs, in an IP network, a normal communication between the mobile terminal and a normal communication terminal via a first call control apparatus S-CSCF#1, and an emergency-communication between the mobile terminal and an emergency-communication terminal via a second call control apparatus S-CSCF#2, including an emergency-communication session establishment processing unit 14 configured to perform an emergency-communication session establishment process between the mobile terminal UE and the emergency-communication terminal, without performing an emergency-communication location registration process for the mobile terminal in the second call control apparatus S-CSCF#2, when a normal-communication location registration process for the mobile terminal is completed in the first call control apparatus S-CSCF#1.

Full Text

DESCRIPTION
MOBILE TERMINAL AND MOBILE COMMUNICATION SYSTEM
TECHNICAL FIELD
The present invention relates to a mobile terminal and a mobile
communication system, in which normal communications are performed
between the mobile terminal and a normal communication terminal via a first call
control apparatus and emergency-communications are performed between the
mobile terminal and an emergency-communication terminal via a second call
control apparatus, in an IP network including the first and second call control
apparatus.
BACKGROUND ART
The 3rd Generation Partnership Project (3GPP), which is an
international standardization organization for the third generation mobile
communication system, has proposed a mobile communication system capable
of performing emergency-communications between a mobile terminal and an
emergency-communication terminal via an IP network (see Non-patent
Document 1).
As shown in Fig. 1, such mobile communication system includes an IP
network configured of an IMS (IP Multimedia Subsystem) and an IP-CAN
(GPRS/I-WLAN).
Here, the IP-CAN is an acronym standing for "IP-Connectivity Access
Network," GPRS is an acronym for "General Packet Radio Service," and
l-WLAN is an acronym standing for "Interworking Wireless Access Network."
In addition, the IMS is provided with a P-CSCF (Proxy-Call Sever Control
Function), an S-CSCF (Serving-Call Server Control Function), an E-CSCF
(Emergency-Call Server Control Function), and an HSS (Home Subscriber
Server), while the IP-CAN (GPRS/I-WLAN) is provided with a function allowing
the forwarding of IP data (SIP signals or VoIP packets).
Here, the S-CSCF, the E-CSCF and the P-CSCF are SIP (Session
Initiation Protocol) servers (call control apparatus) for controlling a

normal-communication session between a mobile terminal UE and a normal
communication terminal or an emergency-communication session between the
mobile terminal UE and an emergency-communication terminal (PSAP: Public
Safety Answering Point).
Note that, the mobile terminal UE is configured to perform normal
communications between the mobile terminal UE and a normal communication
terminal (not shown in the drawings) via an S-CSCF#1 (first call control
apparatus) and emergency-communications between the mobile terminal UE
and the emergency-communication terminal PSAP, via an S-CSCF#2 (second
call control apparatus) and an E-CSCF.
By referring to Fig. 2, operations to start emergency-communications
between the mobile terminal UE and PSAP in the above-described mobile
communication system will be described.
As shown in Fig. 2, in step S7001, the mobile terminal UE transmits, to
the P-CSCF, an "Normal Registration Request" for requesting that the
S-CSCF#1 perform a normal-communication location registration process
(Normal Registration process) for the mobile terminal UE, by using
normal-communication user identifiers (IMPI: an IP Multimedia Private Identifier
and a Normal IMPU: IP Multimedia Public Identity).
In step S7002, in response to the "Normal Registration Request," the
normal-communication location registration process for the mobile terminal UE is
performed between the mobile terminal UE and the S-CSCF#1 by referring to
the HSS.
Thereafter, in step S7003, the mobile terminal UE transmits, to the
P-CSCF, an "Emergency Registration Request" for requesting that the
S-CSCF#2 perform an emergency-communication location registration process
(Emergency Registration process) for the mobile terminal UE, by using an
emergency-communication user identifier (Emergency IMPU).
In step S7004, in response to the "Emergency Registration Request,"
the emergency-communication location registration process for the mobile
terminal UE is performed between the mobile terminal UE and the S-CSCF#2 by
referring to the HSS.

After the above emergency-communication location registration process
is completed, in step S7005, the mobile terminal UE transmits, to the P-CSCF,
an "Emergency SIP Invite" for requesting that an emergency-communication
session establishment process be performed between the mobile terminal UE
and the PSAP, by using the emergency-communication user identifier.
In step S7006, the P-CSCF forwards the received "Emergency SIP
Invite" to the E-CSCF.
In step S7007, in response to the "Emergency SIP Invite," the
emergency-communication session establishment process (Emergency Session
Establishment process) is performed between the mobile terminal UE and the
PSAP.
The mobile terminal UE can perform emergency-communications
between the mobile terminal UE and the PSAP by using the
emergency-communication session establishment process set as described
above.
However, in the above-described mobile communication system, in
order to allow emergency-communications from a mobile terminal in which a
UICC is not provided (mobile terminal UE of a non-subscribed user), an
emergency-communication location registration process, which is required only
for performing emergency-communications, has to be performed, in addition to
the normal-communication location registration process.
In addition, the above-described mobile communication system requires
to perform both of the normal-communication location registration process and
the emergency-communication location registration process, since a
normal-communication call control! apparatus (S-CSCF#1) is different from an
emergency-communication call control apparatus (S-CSCF#2) provided to a
command station of, for example, police, fire, Japan Coast Guard services or the
like.
Examples of the aforementioned example in which a
normal-communication call control apparatus (S-CSCF#1) is different from an
emergency-communication call control apparatus (S-CSCF#2) includes an
example in which a mobile terminal UE performs an emergency-communication

session establishment process from a network outside its home network.
Accordingly, in the above-described communication system, even when
a normal-communication location registration process for a certain mobile
terminal UE is completed, an emergency-communication registration process for
the mobile terminal UE has to be additionally performed. Thus, the
communication system has a problem that time until starting
emergency-communications is longer.
Non-patent Document 1: 3GPP TS23.167 Ver.7.0.0
DISCLOSURE OF THE INVENTION
The present invention has been made in view of the foregoing problem.
Accordingly, an object of the present invention is to provide a mobile terminal
and a mobile communication system, which can shorten a time until starting an
emergency-communication in an IF3 network.
A first aspect of the invention is summarized as a mobile terminal that
performs a normal communication between the mobile terminal and a normal
communication terminal via a first call control apparatus, and an
emergency-communication between the mobile terminal and an
emergency-communication terminal via a second call control apparatus, in an IP
network including the first call control apparatus and the second call control
apparatus. The mobile terminal includes: an emergency-communication session
establishment processing unit configured to perform an
emergency-communication session establishment process between the mobile
terminal and the emergency-communication terminal, without performing an
emergency-communication location registration process for the mobile terminal
in the second call control apparatus, when a normal-communication location
registration process for the mobile terminal is completed in the first call control
apparatus.
In the first aspect of the invention, the emergency-communication
session establishment processing unit may be configured to perform the
emergency-communication session establishment process between the mobile

terminal and the emergency-communication terminal, without performing the
emergency-communication location registration process for the mobile terminal
in the second call control apparatus, when the normal-communication location
registration process for the mobile terminal is completed in the first call control
apparatus and when a determination is made that not both of the
normal-communication location registration process for the mobile terminal and
the emergency-communication location registration process for the mobile
terminal need to be performed in performing the emergency communication in
the IP network.
In the first aspect of the invention, the emergency-communication
session establishment processing unit may be configured to make the
determination based on information notified from the IP network in performing
the normal-communication location registration process for the mobile terminal.
The first aspect of the invention may be configured to further include an
emergency-communication location registration processing unit configured to
transmit an emergency-communication location registration request for
requesting that the second call control apparatus perform the
emergency-communication location registration process for the mobile terminal,
when the normal-communication location registration process for the mobile
terminal is not completed in the first call control apparatus, and the
emergency-communication session establishment processing unit may be
configured to perform the emergency-communication session establishment
process between the mobile terminal and the emergency-communication
terminal, without performing the normal-communication location registration
process for the mobile terminal in the first call control apparatus, when the
emergency-communication location registration process for the mobile terminal
is completed in the second call control apparatus in response to the
emergency-communication location registration request.
The first aspect of the invention may be configured to include an
emergency-communication location registration processing unit configured to
transmit an emergency-communication location registration request for
requesting that the second call control apparatus perform the

emergency-communication location registration process for the mobile terminal,
when a UICC is not provided in the mobile terminal, and the
emergency-communication session establishment processing unit may be
configured to perform, the emergency-communication session establishment
process between the mobile terminal and the emergency-communication
terminal without performing the normal-communication location registration
process for the mobile terminal in the first call control apparatus, when the
emergency-communication location registration process for the mobile terminal
is completed in the second call control apparatus in response to the
emergency-communication location registration request.
In the first aspect of the invention, the emergency-communication
session establishment processing unit may be configured to make the
determination based on information notified from the IP network in performing a
location registration process in the IP network.
A second aspect of the invention is summarized as a mobile
communication system in which a mobile terminal performs a normal
communication between the mobile terminal and a normal communication
terminal via a first call control apparatus, and performs an
emergency-communication between the mobile terminal and an
emergency-communication terminal via a second call control apparatus, the
normal communication and the emergency-communication being performed via
an IP network including the first call control apparatus and the second call
control apparatus. The mobile terminal is configured to transmit an
emergency-communication session establishment process request for
requesting that an emergency-communication session establishment process be
performed between the mobile terminal and the emergency-communication
terminal, when a normal-communication location registration process for the
mobile terminal is completed in the first call control apparatus, and the IP
network is configured to perform the emergency-communication session
establishment process between the mobile terminal and the
emergency-communication terminal, when the emergency-communication
location registration process for the mobile terminal is not performed in the

second call control apparatus and when the normal-communication location
registration process for the mobile terminal is completed in the first call control
apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an overall configurational view of a general mobile
communication system;
Fig. 2 is a sequential view for illustrating operations of a mobile
communication system according to a conventional art;
Fig. 3 is a functional block diagram of a mobile terminal according to a
first embodiment of the present invention;
Fig. 4 is a flowchart showing overall operations of a mobile
communication system according to the first embodiment of the present
invention;
Fig. 5 is a flowchart at a procedure 1 in the overall operations of the
mobile communication system according to the first embodiment of the present
invention;
Fig. 6 is a flowchart at a procedure 2 in the overall operations of the
mobile communication system according to the first embodiment of the present
invention;
Fig. 7 is a sequential view for illustrating the operations of the mobile
communication system according to the first embodiment of the present
invention;
Fig. 8 is a sequential view for illustrating the operations of the mobile
communication system according to the first embodiment of the present
invention;
Fig. 9 is a sequential view for illustrating the operations of the mobile
communication system according to the first embodiment of the present
invention;
Fig. 10 is a sequential view for illustrating the operations of the mobile
communication system according to the first embodiment of the present
invention;

Fig. 11 is a flowchart showing the overall operations of the mobile
communication system according to the first embodiment of the present
invention;
Fig. 12 is a flowchart at procedure 1 in the overall operations of the
mobile communication system according to the first embodiment of the present
invention;
Fig. 13 is a sequential view for illustrating the operations of the mobile
communication system according to the first embodiment of the present
invention;
Fig. 14 is a sequential view for illustrating the operations of the mobile
communication system according to the first embodiment of the present
invention;
Fig. 15 is a sequential view for illustrating the operations of the mobile
communication system according to the first embodiment of the present
invention; and
Fig. 16 is a sequential view for illustrating the operations of the mobile
communication system according to the first embodiment of the present
invention.
BEST MODES FOR CARRYING OUT THE INVENTION
(Configuration of a mobile communication system according to a first
embodiment of the present invention)
As shown in Fig. 1, a mobile communication system according to the
present embodiment is configured so that a mobile terminal LIE perform normal
communications between the mobile terminal UE and a normal communication
terminal via the S-CSCF#1; and emergency-communications between the
mobile terminal UE and a PSAP (emergency-communication terminal) via the
S-CSCF#2 and the E-CSCF, in the IP network including an S-CSCF#1 (first call
control apparatus), an S-CSCF#2 (second call control apparatus), an E-CSCF,
and a P-CSCF.
Here, as will be described later, such IP network is configured so that an
emergency-communication session establishment process (Emergency Session

Establishment process) between the mobile terminal UE and the PSAP would be
performed even when an emergency-communication location registration
process (Emergency Registration process ) for the mobile terminal UE is not
performed in the S-CSCS#2, as long as a normal-communication location
registration process (Normal Registration process ) for the mobile terminal UE
is completed in the S-CSCS#1.
Referring to Fig. 3, the configuration of the mobile terminal UE according
to the first embodiment of the present invention will be described.
The mobile terminal UE according to the present embodiment is
configured so as to perform normal communications between the mobile
terminal UE and a normal communication terminal via the S-CSCF#1; and
emergency-communications between the mobile terminal UE and the PSAP via
the S-CSCF#2 and the E-CSCF in the above-described IP network.
As shown in Fig. 3, the mobile terminal UE according to the present
embodiment is provide with a UICC detecting unit 11, a Normal Registration
processing unit 12, an Emergency Registration processing unit 13, and an
Emergency Session Establishment processing unit 14.
The UICC detecting unit 11 is configured to detect whether a UICC
(Universal Integrated Circuit Card) is provided in the mobile terminal UE.
The Normal Registration processing unit 12 is configured to perform a
normal-communication location registration process (Normal Registration
process) for the mobile terminal UE in the S-CSCF#1 when a predetermined
condition, for example, at power-on of the mobile terminal UE is satisfied.
Specifically, in order to perform the normal-communication location
registration process , the Normal Registration processing unit 12 is configured to
transmit, to the P-CSCF, a normal registration request for requesting that a
normal-communication location registration process be performed by using
normal-communication user identifiers.
The Emergency Registration processing unit 13 is configured to perform
an emergency-communication location registration process (Emergency
Registration process) for the mobile terminal UE in the S-CSCF#2 when a
predetermined condition is satisfied.

Specifically, the Emergency Registration processing unit 13 is configured
to transmit, to the P-CSCF, an emergency registration request for requesting that
an emergency-communication location registration process be performed by
using emergency-communication user identifiers, in order to perform the
emergency-communication location registration process.
For example, when a UICC is not provided in the mobile terminal UE or a
normal-communication location registration process for the mobile terminal UE is
not completed in the S-CSCF#1, the Emergency Registration processing unit 13
is configured to transmit, to the P-CSCF, an emergency registration request for
requesting that the S-CSCF#2 perform emergency-communication location
registration process for the mobile terminal UE by using
emergency-communication user identifiers.
When the predetermined condition is satisfied, the Emergency Session
Establishment processing unit 14 is configured to perform an
emergency-communication session establishment process (Emergency Session
Establishment process) for performing emergency-communications between the
mobile terminal UE and the PSAP via the S-CSCF#2 and the E-CSCF.
Specifically, in order to perform such emergency-communication session
establishment process, the Emergency Session Establishment processing unit
14 is configured to transmit an emergency-communication session
establishment process request (Emergency SIP Invite) for requesting that an
emergency-communication session establishment process be performed
between the mobile terminal UE and the PSAP.
For example, the Emergency Session Establishment processing unit 14
is configured to perform an emergency-communication session establishment
process between the mobile terminal UE and the PSAP without performing an
emergency-communication location registration process for the mobile terminal
UE in the S-CSCF#2, when a normal-communication location registration
process for the mobile terminal UE is completed in the S-CSCF#1, and when it is
determined that not both of the normal-communication for the mobile terminal
UE and emergency-communication location registration process for the mobile
terminal UE need to be performed in order to perform the

emergency-communications in the above-described IP network.
Here, the Emergency Session Establishment processing unit 14 may be
configured to make the above-described determination based on information
(determination key, for example) notified from the IP network in performing the
normal-communication location registration process for the mobile terminal UE.
In addition, the Emergency Session Establishment processing unit 14 is
configured to perform an emergency-communication session establishment
process between the mobile terminal UE and the PSAP without performing a
normal-communication location registration process for the mobile terminal UE
in the S-CSCF#1, when an emergency-communication location registration
process for the mobile terminal UE is completed in the S-CSCF #1 in response
to the above-mentioned emergency registration request.
(Operations of the mobile communication system according to the first
embodiment of the present invention)
Hereinafter, operations of the mobile communication system according
to the present embodiment will be described by referring to Figs. 4 to 10.
Specifically, the operations of the mobile terminal UE according to the
present embodiment will be described by referring to Figs. 4 to 6 and the
operations of the mobile communication system according to the present
embodiment will be described by referring to Figs. 7 to 10.
As shown in Fig. 4, in step S101, an emergency call to be transmitted
from the mobile terminal UE to the PSAP occurs.
In step S102, the mobile terminal UE determines whether a UICC is
provided in the mobile terminal UE.
When it is determined that a UICC is provided in the mobile terminal UE,
the present operation proceeds to step S103 to execute the procedure 1 shown
in Fig. 5. When it is determined that a UICC is not provided in the mobile
terminal UE, the present operation proceeds to step S104 to execute the
procedure 2 shown in Fig. 6.
Firstly, with reference to Fig. 5, operations of the procedure 1 performed
by the mobile terminal UE will be described.

As shown in Fig. 5, in step S201, the mobile terminal UE determines
whether a normal-communication location registration process for the mobile
terminal UE is completed in the S-CSCF#1.
When it is determined that the normal-communication location
registration process is completed, the present operation proceeds to step S202.
When it is determined that the normal-communication location registration
process is not completed, the procedure 2 shown in Fig. 6 is executed in the
present operation.
In step S202, the mobile terminal UE determines whether an
emergency-communication location registration process for the mobile terminal
UE needs to be performed in the S-CSCF#2, based on information
(determination key, for example) notified from the IP network in performing the
normal-communication location registration process for the mobile terminal UE.
In other words, the mobile terminal UE determines whether both of the
normal-communication for the mobile terminal UE and the
emergency-communication location registration process for the mobile terminal
UE need to be performed in order to perform emergency-communications in the
IP network.
When it is determined that both of the normal-communication location
registration process and the emergency-communication location registration
process need to be performed, the present operation proceeds to step S203.
When it-is determined that not both of the normal-communication location
registration process and the emergency-communication location registration
process need to be performed, the present operation proceeds to step S105 in
Fig. 4.
In step S203, the mobile terminal UE transmits, to the P-CSCF, an
emergency registration request for requesting that an
emergency-communication location registration process be performed by using
emergency-communication user identifiers, in order to perform the
emergency-communication location registration process .
In step S204, the mobile terminal UE performs the emergency
registration between the mobile terminal UE and the S-CSCF#2. Thereafter,

the present operation proceeds to step S105 in Fig. 4.
Secondly, with referring to Fig. 6, operations of the procedure 2
performed by the mobile terminal UE will be described.
As shown in Fig. 6, in step S301, the mobile terminal UE transmits, to
the P-CSCF, an emergency registration request for requesting that the
S-CSCF#2 perform an emergency-communication location registration process
for the mobile terminal UE by using emergency-communication user identifiers.
In step S302, the mobile terminal UE determines whether a
normal-communication location registration process for the mobile terminal UE
needs to be performed in the S-CSCF#1, based on an instruction included in a
response from the P-CSCF for the emergency registration request. In other
words, the mobile terminal UE determines whether a normal-communication
location registration process for the mobile terminal UE needs to be performed
before an emergency-communication location registration process for the mobile
terminal UE is performed in the IP network.
When it is determined that the normal-communication location
registration process needs to be performed, the present operation proceeds to
step S303. When it is determined that the normal-communication location
registration process does not need to be performed, the present operation
proceeds to step S305.
In step S303, the mobile terminal UE transmits, to the P-CSCF, a normal
registration request for requesting that a normal-communication location
registration process be performed by using normal-communication user
identifiers, in order to perform such normal-communication location registration
process.
In step S304, the mobile terminal UE performs a normal-communication
location registration process for the mobile terminal UE between the mobile
terminal UE and the S-CSCF#1. Thereafter, the present operation proceeds to
step S202 in Fig. 5.
Note that, when a UICC is not provided in the mobile terminal UE, the
mobile terminal UE cannot perform the normal-communication location
registration process by using a normal-communication user identifier and thus

cannot perform emergency-communications between the mobile terminal UE
and the PSAP.
In step S305, the mobile terminal UE performs an
emergency-communication location registration process for the mobile terminal
UE between the mobile terminal UE and the S-CSCF#2. Thereafter, the
present operation proceeds to step S105 in Fig. 4.
In step S105, the mobile terminal UE transmits, to the P-CSCF,
emergency-communication session establishment process request (Emergency
SIP Invite) for requesting that an emergency-communication session
establishment process be performed between the mobile terminal UE and the
PSAP, in order to perform the emergency-communication session establishment
process between the mobile terminal UE and the PSAP.
In step S106, the mobile terminal UE performs the
emergency-communication session establishment process between the mobile
terminal UE and the PSAP, the emergency-communication session
establishment process being used for emergency-communications.
Next, operations (in four cases) to start emergency-communications
between the mobile terminal UE and a PSAP in the mobile communication
system according to the present embodiment will be described by referring to
Figs. 7 to 10.
Firstly, the operations of the mobile communication system according to
a first case of the present embodiment will be described by referring to Fig. 7.
In the first case, as shown in Fig. 7, the mobile terminal UE determines:
that a UICC is provided in the mobile terminal UE in step S1001; that a
normal-communication location registration process for the mobile terminal UE is
completed in the S-CSCF#1 in step S1002; and that, in step S2003, not both of
the normal-communication location registration process and the
emergency-communication location registration process for the mobile terminal
UE need to be performed, in performing the emergency-communications in the
IP network.
In such case, in step S1004, the mobile terminal UE transmits, to the
P-CSCF, an emergency-communication session establishment process request

for requesting that an emergency-communication session establishment process
(Emergency Session Establishment process) be performed between the mobile
terminal UE and the PSAP by using normal-communication user identifiers,
without performing an emergency-communication location registration process
for the mobile terminal UE in the S-CSCF#2.
In step S1005, the P-CSCF forwards the received
emergency-communication session establishment process request to the
E-CSCF.
In step S1006, the E-CSCF forwards the received
emergency-communication session establishment process request to the PSAP.
In step S1007, an emergency-communication location registration
process for the mobile terminal UE is not performed in the S-CSCF#2.
Nonetheless, the emergency-communication session establishment process
between the mobile terminal UE and the PSAP is performed, since the
normal-communication location registration process for the mobile terminal UE is
completed in the S-CSCF#1.
By using the emergency-communication session establishment process
set as described above, the mobile terminal UE can perform
emergency-communications between the mobile terminal UE and the PSAP.
Secondly, the operations of the mobile communication system according
to a second case of the present embodiment will be described by referring to Fig.
8.
In the second case, as shown in Fig. 8, the mobile terminal UE
determines: that a UICC is provided in the mobile terminal UE in step S2001;
that a normal-communication location registration process for the mobile
terminal UE is completed in the S-CSCF in step S2002; and that, in step S2003,
both of the normal-communication location registration process and the
emergency-communication location registration process for the mobile terminal
UE need to be performed in order to perform emergency-communications in the
IP network.
In step S2004, the mobile terminal UE transmits, to the P-CSCF, an
emergency registration request for requesting that the S-CSCF#2 perform an

emergency-communication location registration process for the mobile terminal
UE by using emergency-communication user identifiers.
In step S2005, in response to the emergency registration request, an
emergency-communication location registration process for the mobile terminal
UE is performed between the mobile terminal UE and the S-CSCF#2, by
referring to the HSS.
In step S2006, the mobile terminal UE transmits, to the P-CSCF, an
emergency-communication session establishment process request (Emergency
SIP Invite) for requesting that an emergency-communication session
establishment process be performed between the mobile terminal UE and the
PSAP by using emergency-communication user identifiers, after the
emergency-communication location registration process is completed.
In step S2007, the P-CSCF forwards the received Emergency SIP Invite
to the E-CSCF.
In step S2008, the E-CSCF forwards the received
Emergency-communication session establishment process request to the PSAP.
In step S2009, in response to the Emergency SIP Invite, the
emergency-communication session establishment process between the mobile
terminal UE and the PSAP is performed between the mobile terminal UE and the
PSAP.
By using the emergency-communication session establishment process
set as described above, the mobile terminal UE can perform
emergency-communications between the mobile terminal UE and the PSAP.
Thirdly, the operations of the mobile communication system according to
a third case of the present embodiment will be described while referring to Fig. 9.
In the third case, as shown in Fig. 9, the mobile terminal UE determines:
that a UICC is provided in the mobile terminal UE in step S3001; and that a
normal-communication location registration process for the mobile terminal UE is
not completed in the S-CSCF#1 in step S3002.
In step S3003, the mobile terminal UE transmits, to the P-CSCF, an
emergency registration request for requesting that the S-CSCF#2 perform an
emergency-communication location registration process for the mobile terminal

UE by using emergency-communication user identifiers.
In step S3004, in response to the emergency registration request, the
P-CSCF transmits a response including an instruction indicating whether or not a
normal-communication location registration process for the mobile terminal UE
needs to be performed before performing an emergency-communication location
registration process for the mobile terminal UE in the IP network.
In step S3005, the mobile terminal UE determines, based on the
response from the P-CSCF, whether or not a normal-communication location
registration process for the mobile terminal UE needs to be performed before
performing an emergency-communication location registration process for the
mobile terminal UE in the IP network.
Here, in the third case, it is determined that a normal-communication
location registration process for the mobile terminal UE needs to be performed
before an emergency-communication location registration process for the mobile
terminal UE is performed in the IP network.
In step S3006, the mobile terminal UE transmits, to the P-CSCF, a
normal registration request for requesting that the S-CSCF#1 perform the
normal-communication location registration process (Normal Registration
process) for the mobile terminal UE by using normal-communication user
identifiers.
In step S3007, in response to the normal registration request, the
normal-communication location registration process for the mobile terminal UE is
performed between the mobile terminal UE and the S-CSCF#1 by referring to
the HSS.
In step S3008, the mobile terminal UE determines whether an
emergency-communication location registration process for the mobile terminal
UE needs to be performed in the S-CSCF#2, based on information
(determination key, for example) notified from the IP network in the
normal-communication location registration process for the mobile terminal UE
performed in step S3007. That is, the mobile terminal UE determines whether
both of the normal-communication location registration process and the
emergency-communication location registration process for the mobile terminal

UE need to be performed, in performing emergency-communications in the IP
network.
Here, in the third case, assume that it is determined that not both of the
normal-communication location registration process and the
emergency-communication location registration process for the mobile terminal
UE need to be performed, in performing the emergency-communications.
In step S3009, the mobile terminal UE transmits, to the P-CSCF, an
Emergency-communication session establishment process request for
requesting that an emergency-communication session establishment process be
performed between the mobile terminal UE and the PSAP by using
normal-communication user identifiers without performing an
emergency-communication location registration process for the mobile terminal
UE in the S-CSCF#2.
In step S3010, the P-CSCF forwards the received
Emergency-communication session establishment process request to the
E-CSCF.
In step S3011, the E-CSCF forwards the received
Emergency-communication session establishment process request to the PSAP.
In step S3012, an emergency-communication location registration
process for the mobile terminal UE is not performed in the S-CSCF#2.
Nonetheless, an emergency-communication session establishment process
between the mobile terminal UE and the PSAP is performed, since in the
above-described IP network, the normal-communication location registration
process for the mobile terminal UE is completed in the S-CSCF#1.
By using the emergency-communication session establishment process
set as described above, the mobile terminal UE can perform
emergency-communications between the mobile terminal UE and the PSAP.
Fourthly, the operations of the mobile communication system according
to a fourth case of the present embodiment will be described while referring to
Fig. 10.
In the fourth case, as shown in Fig. 10, the mobile terminal UE
determines: that a UICC is provided in the mobile terminal UE in step S4001;

and that a normal-communication location registration process for the mobile
terminal UE is not completed in the S-CSCF#1, in step S4002.
Alternatively, in step S4001 of the fourth case, the mobile terminal UE
may determine that a UICC is not provided in the mobile terminal UE, as shown
in Fig. 10.
In either case, in step S4003, the mobile terminal UE transmits, to the
P-CSCF, an emergency registration request for requesting that the S-CSCF#2
perform an emergency-communication location registration process for the
mobile terminal UE by using emergency-communication user identifiers.
In step S4004, in response to the emergency registration request, the
P-CSCF determines that a normal-communication location registration process
for the mobile terminal UE does not need to be performed before the
emergency-communication location registration process for the mobile terminal
UE is performed in the IP network. Then, the emergency-communication
location registration process for the mobile terminal UE is performed between
the mobile terminal UE and the S-CSCF#2 by referring to the HSS.
In step S4005, the mobile terminal UE transmits, to the P-CSCF, an
emergency-communication session establishment process request (Emergency
SIP Invite) for requesting that an emergency-communication session
establishment process be performed between the mobile terminal UE and the
PSAP by using emergency-communication user identifiers after the
above-described emergency-communication location registration process is
completed.
In step S4006, the P-CSCF forwards the received Emergency SIP Invite
to the E-CSCF.
In step S4007, the E-CSCF forwards the received
emergency-communication session establishment process request to the PSAP.
In step S4008, in response to the Emergency SIP Invite, the
emergency-communication session establishment process between the mobile
terminal UE and the PSAP is performed between the mobile terminal UE and the
PSAP by referring to the HSS, although a normal-communication location
registration process for the mobile terminal UE is not performed in the

S-CSCF#1.
By using the emergency-communication session establishment process
set as described above, the mobile terminal UE can perform
emergency-communications between the mobile terminal UE and the PSAP.
(Advantageous effects of the mobile communication system according to the first
embodiment of the present invention)
In the mobile terminal and the mobile communication system according
to the present embodiment, an emergency-communication session
establishment process would be performed between the mobile terminal UE and
the PSAP without performing an emergency-communication location registration
process for the mobile terminal UE in the S-CSCF#2, when a
normal-communication location registration process for the mobile terminal is
completed in the S-CSCF#1 and it is determined that not both of the
normal-communication location registration process and the
emergency-communication location registration process for the mobile terminal
UE need to be performed, in performing the emergency-communications in the
IP network. Accordingly, time until starting emergency-communications in an IP
network can be shortened.
In addition, in the mobile terminal and the mobile communication system
according to the present embodiment, when it is determined that both of the
normal-communication location registration process and the
emergency-communication location registration process for the mobile terminal
UE need to be performed in performing the emergency-communications in the IP
network and when a normal-communication location registration process for the
mobile terminal UE is completed in the S-CSCF#1, an
emergency-communication session establishment process is performed
between the mobile terminal UE and the PSAP after an
emergency-communication location registration process for the mobile terminal
UE is performed in the S-CSCF#2. Accordingly, the mobile terminal and the
mobile communication system according to the present embodiment are
applicable to a conventional IP network in which both of the

normal-communication location registration process and the
emergency-communication location registration process for the mobile terminal
UE need to be performed, in performing emergency-communications. Also, the
mobile terminal and the mobile communication system according to the present
embodiment are applicable to the IP network according to the present invention
in which not both of the normal-communication location registration process and
the emergency-communication location registration process for the mobile
terminal UE need to be performed in performing emergency-communications.
In addition, when a UICC is not provided in the mobile terminal UE, or
when an emergency-communication location registration process for the mobile
terminal UE is completed in the 3-CSCF#2 in response to an emergency
registration request transmitted by the mobile terminal UE and when a
normal-communication location registration process for the mobile terminal UE is
not completed in the S-CSCF#1, the mobile terminal and mobile communication
system according to the present embodiment are configured that an
emergency-communication session establishment process would be performed
between the mobile terminal UE and the PSAP without performing a
normal-communication location registration process for the mobile terminal UE
in the S-CSCF#1. Accordingly, time until starting emergency-communications
in the IP network can be shortened.
(A mobile communication system according to a second embodiment of the
present invention)
Referring to Figs. 11 to 16, a mobile communication system according to
a second embodiment of the present invention will be described.
In the present embodiment, the above-described S-CSCF#1 (first call
control apparatus) and the S-CSCF#2 (second call control apparatus) are
provided in the same apparatus (S-CSCF).
Specifically, operations of the mobile terminal UE according to the
present embodiment will be described by referring to Figs. 11 and 12, and
operations of the mobile communication system according to the present
embodiment will be described by referring to Figs. 13 to 16.

As shown in Fig. 11, in step S501, an emergency call to be performed
from the mobile terminal UE to the PSAP occurs.
In step S102, the mobile terminal UE determines whether a UICC is
provided in the mobile terminal UE.
When it is determined that a UICC is provided in the mobile terminal UE,
the present operation proceeds to step S503 to execute the procedure 1.
When it is determined that a UICC is not provided in the mobile terminal UE, the
present operation proceeds to step S504.
Here, by referring to Fig. 12, operations of the procedure 1 performed by
the mobile terminal UE will be described.
As shown in Fig. 12, in step S601, the mobile terminal UE determines
whether or not the mobile terminal UE is located in a Home network or in a
visited network, by using information acquired from an IP network in performing,
for example, a GPRS (General Packet Radio Service) attach process
(registration process for GPRS) or l-WLAN attach process (registration process
for l-WLAN), based on information notified from the IP network in performing a
registration process in the IP network.
When it is determined that the mobile terminal UE is located in the Home
network, the present operation proceeds to step S602. When it is determined
that the mobile terminal UE is located in the visited network, the present
operation proceeds to step S603.
In step S602, the mobile terminal UE determines whether a
normal-communication location registration process for the mobile terminal UE is
completed in the S-CSCF#1.
When it is determined that the normal-communication location
registration process for the mobile terminal UE is completed, the present
operation proceeds to step S504 in Fig. 11. When it is determined that the
normal-communication location registration process for the mobile terminal UE is
not completed, the present operation proceeds to step S603.
In step S603, the mobile terminal UE transmits, to the P-CSCF, an
emergency registration request for requesting that an
emergency-communication location registration process be performed by using

emergency-communication user identifiers, in order to perform the
emergency-communication location registration process.
In step S604, after the mobile terminal UE performs the emergency
registration between the mobile terminal UE and the S-CSCF#2, the present
operation proceeds to step S504 in Fig. 11.
Specifically, the mobile terminal UE determines whether an
emergency-communication location registration process for the mobile terminal
UE needs to be performed in the S-CSCF#2 based on information
(determination key, for example) notified from the IP network in performing the
registration process for the mobile terminal UE in the IP network. In other
words, the mobile terminal UE determines whether both of the
normal-communication location registration process and the
emergency-communication location registration process for the mobile terminal
UE need to be performed in performing the emergency-communications in the IP
network.
Specifically, when it is determined that the mobile terminal UE is located
in the Home network, based on the information (determination key, for example)
notified from the IP network in the registration process for the mobile terminal UE
in the IP network, the mobile terminal UE determines that not both of the
normal-communication location registration process and the
emergency-communication location registration process for the mobile terminal
UE need to be performed in performing the emergency-communications in the IP
network.
On the other hand, when it is determined that the mobile terminal UE is
not located in the Home network (that is, located in the visited network), based
on the information (for example, determination key) notified from the IP network
in the registration process for the mobile terminal UE in the IP network, the
mobile terminal UE determines that both of the normal-communication location
registration process and the emergency-communication location registration
process for the mobile terminal UE need to be performed in performing the
emergency-communications in the IP network.
In step S504, the mobile terminal UE transmits, to the P-CSCF, an

emergency-communication session establishment process request (Emergency
SIP Invite) for requesting that an emergency-communication session
establishment process be performed between the mobile terminal UE and the
PSAP, in order to perform an emergency-communication session establishment
process used for emergency-communications between the mobile terminal UE
and the PSAP.
In step S505, the mobile terminal UE performs the
emergency-communication session establishment process used for
emergency-communications between the mobile terminal UE and the PSAP.
Next, operations (in four cases) to start emergency-communications
between the mobile terminal UE and the PSAP in the mobile communication
system according to the present embodiment will be described by referring to
Figs. 13 to 16.
Firstly, the operations of the mobile communication system according to
a first case of the present embodiment will be described by referring to Fig. 13.
In the first case, as shown in Fig. 13, the mobile terminal UE determines:
that a UICC is provided in the mobile terminal UE in step S5001; that the mobile
terminal UE is located in the Home network in step S5002; and that a
normal-communication location registration process for the mobile terminal UE is
completed in step S5003.
In such case, in step S5004, the mobile terminal UE transmits, to the
P-CSCF, an emergency-communication session establishment process request
(Emergency SIP Invite) for requesting that an emergency-communication
session establishment process (Emergency Session Establishment process) be
performed between the mobile terminal UE and the PSAP by using
normal-communication user identifiers without performing an
emergency-communication location registration process for the mobile terminal
UE in the S-CSCF#2.
In step S5005, the P-CSCF forwards the received
Emergency-communication session establishment process request to the
E-CSCF.
In step S5006, the E-CSCF forwards the received

Emergency-communication session establishment process request to the PSAP.
In step S5007, an emergency-communication location registration
process for the mobile terminal UE is not performed in the S-CSCF#2 in the
above-described IP network. Nonetheless, an emergency-communication
session establishment process between the mobile terminal UE and the PSAP is
performed, since the normal-communication location registration process for the
mobile terminal UE is completed in the S-CSCF#1.
By using the emergency-communication session establishment process
set as described above, the mobile terminal UE can perform
emergency-communications between the mobile terminal UE and the PSAP.
Secondly, the operations of the mobile communication system according
to a second case of the present embodiment will be described by referring to Fig.
14.
In the second case, as shown in Fig. 14, the mobile terminal UE
determines: that a UICC is provided in the mobile terminal UE in step S6001;
that the mobile terminal UE is located in the Home network in step S6002; and
that a normal-communication location registration process for the mobile
terminal UE is not completed in step S6003.
In step S6004, the mobile terminal UE transmits, to the P-CSCF, an
emergency registration request for requesting that the S-CSCF#2 perform an
emergency-communication location registration process for the mobile terminal
UE by using emergency-communication user identifiers.
In step S6005, in response to the emergency registration request, the
emergency-communication location registration process for the mobile terminal
UE is performed between the mobile terminal UE and the S-CSCF#2 by referring
to the HSS.
In step S6006, the mobile terminal UE transmits, to the P-CSCF, an
emergency-communication session establishment process request (Emergency
SIP Invite) for requesting that an emergency-communication session
establishment process be performed between the mobile terminal UE and the
PSAP by using emergency-communication user identifier, after the
emergency-communication location registration process is completed.

In step S6007, the P-CSCF forwards the received Emergency SIP Invite
to the E-CSCF.
In step S6008, the E-CSCF forwards the received
Emergency-communication session establishment process request to the PSAP.
In step S6009, in response to the Emergency SIP Invite, an
emergency-communication session establishment process between the mobile
terminal UE and the PSAP is performed between the mobile terminal UE and the
PSAP.
By using the emergency-communication session establishment process
set as described above, the mobile terminal UE can perform
emergency-communications between the mobile terminal UE and the PSAP.
Thirdly, the operations of the mobile communication system according to
a third case of the present embodiment will be described by referring to Fig. 15.
In the third case, as shown in Fig. 15, the mobile terminal UE
determines: that a UICC is provided in the mobile terminal UE in step S7001;
and that the mobile terminal UE is not located in the Home network in step
S7002.
In step S7003, the mobile terminal UE transmits, to the P-CSCF, an
emergency registration request for requesting that the S-CSCF#2 perform an
emergency-communication location registration process for the mobile terminal
UE by using emergency-communication user identifiers.
In step S7004, in response to the emergency registration request, an
emergency-communication location registration process for the mobile terminal
UE is performed between the mobile terminal UE and S-CSCF#2 by referring to
the HSS.
In step S7005, the mobile terminal UE transmits, to the P-CSCF, an
Emergency-communication session establishment process request for
requesting that an emergency-communication session establishment process be
performed between the mobile terminal UE and the PSAP by using a user
normal-communication user identifier without performing an
emergency-communication location registration process for the mobile terminal
UE in the S-CSCF#2.

In step S7006, the P-CSCF forwards the received
Emergency-communication session establishment process request to the
E-CSCF.
In step S7007, the E-CSCF forwards the received
Emergency-communication session establishment process request to the PSAP.
In step S7008, in the above-described IP network, an
emergency-communication location registration process for the mobile terminal
UE is not performed in the S-CSCF#2. Nonetheless, an
emergency-communication session establishment process between the mobile
terminal UE and the PSAP is performed, since the normal-communication
location registration process for the mobile terminal UE is completed in the
S-CSCF#1.
By using the emergency-communication session establishment process
set as described above, the mobile terminal UE can perform
emergency-communications between the mobile terminal UE and the PSAP.
Fourthly, the operations of the mobile communication system according
to a fourth case of the present embodiment will be described by referring to Fig.
16.
In the fourth case, as shown in Fig. 16, the mobile terminal UE
determines, in step S8001, that a UICC is not provided in the mobile terminal
UE.
In step S8002, the mobile terminal UE transmits, to the P-CSCF, an
emergency-communication session establishment process request (Emergency
SIP Invite) for requesting that an emergency-communication session
establishment process be performed between the mobile terminal UE and the
PSAP by using emergency-communication user identifiers.
In step S8003, the P-CSCF forwards the received Emergency SIP Invite
to the E-CSCF.
In step S8004, the E-CSCF forwards the received
Emergency-communication session establishment process request to the PSAP.
In step S8005, a normal-communication location registration process for
the mobile terminal UE is not performed in the S-CSCF#1. Nonetheless, an

emergency-communication session establishment process between the mobile
terminal UE and the PSAP is performed between the mobile terminal UE and the
PSAP by referring to the HSS in response to the Emergency SIP Invite.
By using the emergency-communication session establishment process
set as described above, the mobile terminal UE can perform
emergency-communications.
As has been described above, the present invention has been described
by using the above-described embodiments. However, it is obvious for those
who are in the art that the present invention is not limited to the embodiments
described herein. The present invention can be amended and be implemented
as modified embodiments without departing from the contents and scope of the
present invention, which are defined by the description of claims. Accordingly,
the description of the present invention is intended to show an illustrative
example, and not intended to limit the present invention.
INDUSTRIAL APPLICABILITY
As described above, the present invention can provide a mobile terminal
and a mobile communication system, which can shorten a time until starting an
emergency-communication in an IP network.

CLAIMS
[1] A mobile terminal that performs a normal communication between the
mobile terminal and a normal communication terminal via a first call control
apparatus, and an emergency-communication between the mobile terminal and
an emergency-communication terminal via a second call control apparatus, in an
IP network including the first call control apparatus and the second call control
apparatus, the mobile terminal comprising:
an emergency-communication session establishment processing unit
configured to perform an emergency-communication session establishment
process between the mobile terminal and the emergency-communication
terminal, without performing an emergency-communication location registration
process for the mobile terminal in the second call control apparatus, when a
normal-communication location registration process for the mobile terminal is
completed in the first call control apparatus.
[2] The mobile terminal according to claim 1, wherein
the emergency-communication session establishment processing unit is
configured to perform the emergency-communication session establishment
process between the mobile terminal and the emergency-communication
terminal, without performing the emergency-communication location registration
process for the mobile terminal in the second call control apparatus, when the
normal-communication location registration process for the mobile terminal is
completed in the first call control apparatus and when a determination is made
that not both of the normal-communication location registration process for the
mobile terminal and the emergency-communication location registration process
for the mobile terminal need to be performed in performing the emergency
communication in the IP network.
[3] The mobile terminal according to claim 2, wherein
the emergency-communication session establishment processing unit is
configured to make the determination based on information notified from the IP

network in performing the normal-communication location registration process
for the mobile terminal.
[4] The mobile terminal according to claim 1, comprising:
an emergency-communication location registration processing unit
configured to transmit an emergency-communication location registration
request for requesting that the second call control apparatus perform the
emergency-communication location registration process for the mobile terminal,
when the normal-communication location registration process for the mobile
terminal is not completed in the first call control apparatus, wherein
the emergency-communication session establishment processing unit is
configured to perform the emergency-communication session establishment
process between the mobile terminal and the emergency-communication
terminal, without performing the normal-communication location registration
process for the mobile terminal in the first call control apparatus, when the
emergency-communication location registration process for the mobile terminal
is completed in the second call control apparatus in response to the
emergency-communication location registration request.
[5] The mobile terminal according to claim 1, comprising:
an emergency-communication location registration processing unit
configured to transmit an emergency-communication location registration
request for requesting that the second call control apparatus perform the
emergency-communication location registration process for the mobile terminal,
when a UICC is not provided in the mobile terminal, wherein
the emergency-communication session establishment processing unit is
configured to perform, the emergency-communication session establishment
process between the mobile terminal and the emergency-communication
terminal without performing the normal-communication location registration
process for the mobile terminal in the first call control apparatus, when the
emergency-communication location registration process for the mobile terminal
is completed in the second call control apparatus in response to the

emergency-communication location registration request.
[6] The mobile terminal according to claim 2, wherein
the emergency-communication session establishment processing unit is
configured to make the determination based on information notified from the IP
network in performing a location registration process in the IP network.
[7] A mobile communication system in which a mobile terminal performs a
normal communication between the mobile terminal and a normal
communication terminal via a first call control apparatus, and performs an
emergency-communication between the mobile terminal and an
emergency-communication terminal via a second call control apparatus, the
normal communication and the emergency-communication being performed via
an IP network including the first call control apparatus and the second call
control apparatus, wherein
the mobile terminal is configured to transmit an
emergency-communication session establishment process request for
requesting that an emergency-communication session establishment process be
performed between the mobile terminal and the emergency-communication
terminal, when a normal-communication location registration process for the
mobile terminal is completed in the first call control apparatus, and
the IP network is configured to perform the emergency-communication
session establishment process between the mobile terminal and the
emergency-communication terminal, when the emergency-communication
location registration process for the mobile terminal is not performed in the
second call control apparatus and when the normal-communication location
registration process for the mobile terminal is completed in the first call control
apparatus.

A mobile terminal UE according to the present invention performs, in an
IP network, a normal communication between the mobile terminal and a normal
communication terminal via a first call control apparatus S-CSCF#1, and an
emergency-communication between the mobile terminal and an
emergency-communication terminal via a second call control apparatus
S-CSCF#2, including an emergency-communication session establishment
processing unit 14 configured to perform an emergency-communication session
establishment process between the mobile terminal UE and the
emergency-communication terminal, without performing an emergency-communication location registration process for the mobile terminal
in the second call control apparatus S-CSCF#2, when a normal-communication
location registration process for the mobile terminal is completed in the first call
control apparatus S-CSCF#1.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=tBeFV6wySXW7y2g3BSA3UQ==&loc=wDBSZCsAt7zoiVrqcFJsRw==

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Patent Number

272070

Indian Patent Application Number

4460/KOLNP/2008

PG Journal Number

12/2016

Publication Date

18-Mar-2016

Grant Date

16-Mar-2016

Date of Filing

05-Nov-2008

Name of Patentee

NTT DoCoMo, INC.

Applicant Address

11-1, NAGATACHO 2-CHOME,CHIYODA-KU, TOKYO 100-6150

Inventors:

#	Inventor's Name	Inventor's Address
1	TAKAKURA, TSUYOSHI	C/O, DOCOMO TECHNOLOGY INC., KOKUSAI-AKASAKA BLDG, 4-5, AKASAKA 2-CHOME, MINATO-KU, TOKYO 107-0052
2	NOGUCHI, KATSUHIRO	C/O INTELLECTUAL PROPERTY DEPARTMENT, NTT DOCOMO, INC. SANNO PARK TOWER, 11-1, NAGATACHO 2-CHOME, CHIYODA-KU, TOKYO 100-6150,

PCT International Classification Number

H04Q 7/38

PCT International Application Number

PCT/JP2007/059314

PCT International Filing date

2007-05-01

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2006-128714	2006-05-02	Japan