WO2011140882A1

WO2011140882A1 - Method and system for implementing emergency short messages

Info

Publication number: WO2011140882A1
Application number: PCT/CN2011/072877
Authority: WO
Inventors: 李世涛; 陈志峰
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-05-10
Filing date: 2011-04-15
Publication date: 2011-11-17
Also published as: CN102244848B; CN102244848A

Abstract

The present invention discloses a method and system for implementing emergency short messages, belonging to the technical field of communications. Wherein, said method includes the following steps: a Proxy Call Session Control Function (P-CSCF) entity receives an emergency message request from a roaming user, and transfers said emergency message request to an Emergency Call Session Control Function (E-CSCF) entity when the requested address obtained by parsing said emergency message request is the number of an emergency short message center; the E-CSCF entity inserts the address of a corresponding Public Safety Answering Point (PSAP) into said emergency message request according to the location information of the user, converts said emergency message request to an emergency short message via an Emergency-IP-Short Message-Gateway (E-IP-SM-GW)，and transfers said emergency short message to said emergency short message center. The requested address in the emergency message request in the present invention is the number of the emergency short message center, and the number enables a visited network to process the emergency message request locally rather than route the emergency message request to the home network of the user, thus improving the performance of the system.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a method and system for implementing an emergency short message. 1 is a schematic diagram of a structure of an IMS (IP Multimedia Core Network Subsystem) based on a short message, including a short message sender UE (User Equipment) 101, and a P-CSCF (Proxy Call session) Control Function, Agent Session Control Function Entity 102), S-CSCF (Serving Call Session Control Function, Service CSCF) 103, Perform monthly call session control function, IP-SM-GW (IP-Short-Message-Gateway, IP Short message gateway) 104, performing conversion between IMS domain instant message to CS (Circuit Switch) domain short message, SMS-GMSC (Gateway MSC For Short Message Services, SMS Service Gateway MSC) /SMS-IWMSC ( Interworking MSC For Short Message Service, MSC) 105, HSS (High Speed Switch) 106, SC (Service Centre, Short Message Center) 107. The number of the short message center is configured on the user's mobile phone, and is generally allocated by the user's home network. The number of the short message center is constant regardless of whether the user is on the home network or roaming on other networks. In the home network. As an IP short message gateway, the IP-SM-GW mainly performs conversion between the IP multimedia subsystem message format and the CS domain short message format. The message service in the above IP multimedia subsystem can implement IMS users to CS users and

The IMS user sends a short message request, where the request address of the SIP (Session Initiation Protocol) message sent by the IMS side is the address of the short message center, so whether the user is in the home network or in the roaming network, the message The request is first sent to the short message center of the user's home location, and then sent by the short message center to the receiving user, and the address of the receiving party and the content of the short message are encapsulated in the SIP message request in the form of a short message. The IMS network elements such as the P-CSCF and the S-CSCF cannot be unpacked for this package. Only the IP-SM-GW can read the package, and only the IP-SM-GW can know the true receiver of the short message. who is it. Due to the increasing use of short messages (regardless of CS domain or IMS domain), mobile phone users are increasingly dependent on the application of short messages, especially for deaf or people who have trouble speaking. We hope that all the business can be completed with short messages. For example: using a short message to complete an emergency call-like service, and sending an urgent short message to the emergency call center, but currently the service such as the emergency call type uses a short message to achieve certain difficulty. First, if the user is currently at the roaming place The short message center as the home location is unable to know the emergency call center setting of the roaming place, so that the short message cannot be sent to the appropriate emergency call center; secondly, according to the demand of the voice emergency call, the emergency call should be in the user The current location processing, that is, when the user roams to another network, the call should not be routed back to the user's home location, but should be processed locally, and according to the related art, the emergency short message will be routed to the home location. In response to these problems, no effective solution has been proposed yet. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method and system for implementing an emergency short message to solve at least the above problems. According to an aspect of the present invention, a method for implementing an emergency short message is provided, including: the proxy session control function entity P-CSCF receives an emergency message request from a roaming user, and the request address parsed from the emergency message request is urgent short When the number of the message center is forwarded, the emergency message request is forwarded to the emergency session control function entity E-CSCF; the E-CSCF inserts the address of the corresponding public safety answering center PSAP into the emergency message request according to the location information of the user, and passes the emergency The IP short message gateway E-IP-SW-GW converts the emergency message request into an emergency short message, wherein the short message center number in the emergency short message is the number of the emergency short message center, the called number is the address of the PSAP, and the forwarding is short Message to the emergency short message center. Before receiving the emergency message request from the roaming user, the P-CSCF further includes: visiting the network to learn that the user roams to the visited network; and providing the number of the emergency short message center to the user. The providing the number of the emergency short message center to the user includes: The mobility management network element of the visited network provides the number of the emergency short message center to the user in the user initiated attach procedure. Or the method includes: after the user accesses the cell, the base station of the cell that visits the network provides the number of the emergency short message center to the user through the broadcast channel. The short message center number and the called number of the short message format package in the emergency message request are the number of the emergency short message center and the emergency call number, respectively. The location information of the above user is obtained by querying the address server LRF, and the corresponding PSAP is allocated for the LRF. The emergency message request carries the location information of the user, and the corresponding PSAP is selected by the E-CSCF according to the location information of the user. The E-IP-SM-GW is set in the E-CSCF, and the emergency message request is converted into an emergency short message by the E-IP-SW-GW: the emergency message request is converted into an emergency short message by the E-CSCF. The emergency short message center is set in the short message center of the visited network, and the number of the emergency short message center is a combination of the number of the short message center and the emergency identifier; or the emergency short message center is an independent device. According to another aspect of the present invention, an emergency short message implementation system is provided, comprising: a proxy session control function entity P-CSCF, configured to receive an emergency message request from a roaming user, and to parse the request from the emergency message request When the address is the number of the emergency short message center, the emergency message request is forwarded to the emergency session control function entity E-CSCF; the E-CSCF is set to insert the address of the corresponding public safety answering center PSAP into the emergency according to the location information of the user. In the message request, the emergency message request is converted into an emergency short message by the emergency IP short message gateway E-IP-SW-GW, wherein the short message center number in the emergency short message is the number of the emergency short message center, and the called number is The address of the PSAP forwards the emergency short message to the emergency short message center. The system further includes: a mobility management network element, configured to provide the number of the emergency short message center to the user in an attach process initiated by the user. With the present invention, the request address in the emergency message request is an emergency call number, which causes the visited network to no longer route the emergency message request back to the user's home network, but to process it in the local network, and solve the short The problem that the message is routed back to the user's home network improves the performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1 is a schematic diagram of an IMS structure based on a short message according to the related art; FIG. 2 is a flowchart of a method for implementing an emergency short message according to Embodiment 1 of the present invention; FIG. 3 is a second embodiment of the present invention. Schematic diagram of the IMS system structure; 4 is a flowchart of a method for implementing an emergency short message according to Embodiment 2 of the present invention; FIG. 5 is a schematic diagram of an attaching process according to Embodiment 2 of the present invention; FIG. 6 is a network for allocating an emergency to a user according to Embodiment 2 of the present invention; FIG. 7 is a flowchart of a method for implementing an emergency short message according to Embodiment 3 of the present invention; FIG. 8 is a flowchart of a method for implementing an emergency short message according to Embodiment 4 of the present invention; The system block diagram of the implementation of the emergency short message of the fifth embodiment of the present invention; and FIG. 10 is a block diagram of the implementation system of another emergency short message according to the fifth embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

The IMS system includes a user equipment UE, a home network, and a visited network. The connection between the home network and each network element in the visited network complies with the relevant communication standard of the IMS. The various embodiments of the present invention are described below as being implemented on the basis of an IMS system. Embodiment 1 FIG. 2 is a flowchart of a method for implementing an emergency short message according to an embodiment of the present invention, including the following steps: Step 202: The P-CSCF receives an emergency message request from a roaming user, and parses the request from the emergency message request. When the request address is the number of the emergency short message center, the emergency message request is forwarded to the E-CSCF (Emergency Session Control Function Entity); wherein the number of the emergency short message center of the user is roaming to the visited network When the number of the emergency short message center is provided, the following two methods can be used: 1) The mobility management network element MME in the visited network will send an emergency short message in the above-mentioned user-initiated attach process. The number of the center is provided to the user; 2) The base station of the cell visiting the network provides the number of the emergency short message center to the user through the broadcast channel after the user accesses the cell. The emergency call center in this embodiment may be a separate device, or may be set in a short message call center in the visited network; if the emergency short message center is set on the short message center of the visited network, the emergency short message center The number can be a combination of the number of the short message center and the emergency identifier. For example, the short message center number is 123456 and the emergency identifier is A. The emergency short message center number can be 123456A or A123456. Step 204: The E-CSCF inserts the address of the corresponding Public Safety Answering Point (PSAP) into the emergency message request according to the location information of the user, and passes the E-IP-SW- The GW (Emergency IP Short Message Gateway) converts the emergency message request into an emergency short message, where the short message center number in the emergency short message is the number of the emergency short message center, and the called number is PSAP. Address, forward emergency short message to emergency short message center. The corresponding PSAP refers to the PSAP of the user's address, and the corresponding PSAP should be as close as possible to the user. The address of the user can be obtained by querying the LRF (Location Retrieval Function). The PSAP may be allocated by the LRF; or, the emergency message request carries the location information of the user, and the location information is used to indicate the address of the user; thus, the visited network may request the address of the user by querying the emergency message, at this time, the PSAP It can be selected by the E-CSCF in the visited network according to the user's address.

The process of forwarding the emergency short message to the emergency short message center by the E-CSCF may be implemented by referring to the method in the prior art. After receiving the emergency short message, the emergency short message center forwards the emergency short message to the existing process. The corresponding PSAP described above is the same as the prior art and will not be described in detail herein. When the user roams to the visited network, the short message sent by the user is returned to the home network of the user for processing, and the request address in the emergency message request in the embodiment of the present invention is an emergency call number, that is, in the visited network. The number of the emergency short message center, so that after the visited network receives the message, the urgent message request will be processed in the current visited network. The request address in the emergency message request in this embodiment is the number of the emergency short message center, and the number causes the visited network to no longer route the emergency message request back to the user's home network, but processes it in the local network to implement an emergency. The short message function is convenient for users to use, which improves the performance of the system. Embodiment 2 FIG. 3 is a schematic structural diagram of an IMS system according to an embodiment of the present invention, including a user equipment UE301, a home network, and a visited network. The visited network in the embodiment of the present invention includes: P-CSCF302, E-CSCF303, and the network The element can be shared with the E-CSCF used for voice emergency calls, or it can be a separate network element that specializes in handling emergency short messages, E-IP-SM-GW304, which specializes in handling emergency short message service, SMS-GMSC/SMS-IWMSC305, E-SC (Emergency Short Message Center) 306, can be built separately, using a separate number, or can be located in a local short message center and share a number with the short message center; PSAP307, is a physical Emergency call center, LRF308, the address server can use the original address server device in the network; MME (Mobility Management Entity, mobile 'Ι" management network element) 309. Based on the system shown in Figure 3, this embodiment provides a For the implementation method of the emergency short message, referring to FIG. 4, the method includes the following steps: Step 402: When an IMS user UE 301 roams to the visited network, at the UE 301 In the process of the local network initiating the attachment, the visited network sends a number of the local emergency short message center E-SC 306 to the UE 301; the number of the E-SC 306 may be that the UE 301 allocates the UE 301 to the UE 301 during the attaching process, or may be When the UE 301 accesses a certain cell, the base station of the cell sends the message to the UE 301 through the broadcast channel of the network; after receiving the emergency short message center number, the user saves the emergency short message center number, when the user needs to send an emergency short message, The emergency short message center number is used to send a message request. Step 404: The UE 301 sends an emergency message request by using the number of the E-SC 306; for example, the UE 301 uses the number of the E-SC 306 as the request address of the IP multimedia subsystem message request, The short message center number of the short message format package in the message request is also the number of the E-SC 306; Step 406, after the P-CSCF 302 receives the message request, it determines whether the request address requested by the message is the number of the E-SC 306. When the address is found to be the number of the E-SC 306, the message request is forwarded to the E-CSCF 303 of the current network. Step 408, the E-CSCF 303 receives the message. After the request, through the address information of the UE301, find a suitable PSAP address, add the PSAP address to the message request, and then forward the message request to the E-IP-SM-GW; The E-CSCF 303 can learn the address information of the UE 301 by interacting with the LRF 308, or can learn the address information provided in the message request. Step 410, the E-IP-SM-GW 304 converts the received message request into a short message form, obtains an emergency short message, and sends the emergency short message to the local E-SC 306 through the SMS-GMSC/SMS-IWMSC 305; The E-IP-SM-GW 304 may be configured in the E-CSCF 303. When the E-IP-SM-GW 304 receives the message request, the IMS-based message request is converted into a short message format, in the process. , Convert the recipient address, that is, the emergency call number, to a specific PSAP address. In step 412, the local E-SC 306 sends the short message to the PSAP 307 according to the address of the PSAP. FIG. 5 is a schematic diagram of an attach process according to an embodiment of the present invention. The attach process includes the following steps: Step 4022: A user UE enters a current network, and sends an attach request to a current network. Step 4024: The current network accesses the user UE. For the authentication of the license, etc., when the UE is allowed to access, the MME of the current network replies to the UE with an attach acceptance response, which carries information such as the local emergency short message center number. FIG. 6 is a schematic diagram of a process for allocating an emergency short message center number to a user in a network according to an embodiment of the present invention. The process includes: Step 402a, the user accesses a cell successfully; Step 402b, the cell base station goes to the user through a broadcast channel. A broadcast message is sent, which carries an emergency short message center number that can be used by the current network. After receiving the emergency short message center number, the user saves it. When the user needs to send an emergency short message, the emergency short message center number is used to send a message request. The request address in the emergency message request in this embodiment is the number of the emergency short message center, and the number causes the visited network to no longer route the emergency message request back to the user's home network, but processes it in the local network to implement an emergency. The short message function is convenient for users to use, which improves the performance of the system. Embodiment 3 FIG. 7 is a flowchart of a method for implementing an emergency short message according to an embodiment of the present invention. The E-CSCF and the E-IP-SM-GW in this embodiment are deployed on the same network element device, including the following. Step 701: The calling user UE1 initiates an emergency message request through the IMS network, where the request address is the number of the emergency short message center obtained through the network, and the message request carries the package of the short message format, where the message is Content, the address information of the recipient, and the emergency short message center number; Step 702: The P-CSCF determines the request address in the message request, and when the P-CSCF receives the request for the message, determines the request address of the message request, when found When the address is an emergency short message center number, the message request is forwarded to the E-CSCF/E-IP-SW-GW of the current network; Step 703, the E-CSCF/E-IP-SW-GW can be obtained through the LRF. The location information of the user, the step may also determine the location of the user by using the location information carried in the emergency message request; Step 704 to Step 705, after receiving the message request, the E-CSCF/E-IP-SM-GW sends the message to the user UE. Return 20 2 receiving the confirmation response message; Step 706, the E-IP-SM-GW converts the message request into a short message format, and according to the location information of the user, changes the address of the receiver to a specific PSAP address, and converts the converted The short message request is sent to the local SMS-GMSC/SMS-IWMSC; Step 707, the SMS-GMSC/SMS-IWMSC sends the short message to the emergency short message center E-SC; Steps 708 to 709, E-SC through SMS - The GMSC/SMS-IWMSC sends the short message to the appropriate PSAP; Steps 710 to 715, the PS AP sends a confirmation 4 to the UE; Step-Step 716 to Step 4: 717, the UE to the E-IP-SM -SW returns 200 OK to confirm. The request address in the emergency message request of this embodiment is the number of the emergency short center, so that the visited network no longer routes the emergency message request back to the user's home network, but processes it in the local network, realizing an emergency short The message function is convenient for users to use, which improves the performance of the system. Embodiment 4 FIG. 8 is a flowchart of a method for implementing an emergency short message according to an embodiment of the present invention. The E-CSCF and the E-IP-SM-GW in the embodiment are separately deployed, and the following steps are included: Step 801: The user UE1 is called to send an emergency message request through the IMS network, where the request address is the number of the emergency short message center obtained through the network, and the message request carries the package of the short message format, where the content of the message and the address of the receiver are included. Information and emergency short message center number; Step 802, when the P-CSCF receives the request for the message, determining the request address requested by the message, and when the address is found to be an emergency short message center number, forwarding the message request to On the E-CSCF of the current network; Step 803, after receiving the message request, the E-CSCF can obtain the location information of the user through the LRF, and at the same time assign a suitable PSAP address to the user, and can also pass the location carried in the emergency message request. The information determines the location of the user, and the E-CSCF assigns a suitable PSAP address to the user; Step 804, the E-CSCF will assign the PSAP address to the user. Adding to the message request, and then forwarding the message request to the E-IP-SM-GW; Steps 805 to 807, after the E-IP-SM-GW owes the request to the message, returning 202 to the user UE to receive the acknowledgement response; Step 808: The E-IP-SM-GW converts the received IMS message request into a short message format, and changes the called number, that is, the emergency call number, to a specific PSAP address, and forwards the short message to the SMS-GMSC/ SMS-IWMSC; Step 809, the SMS-GMSC/SMS-IWMSC sends the short message to the emergency short message center E-SC; Step 810 to Step 811, the E-SC casts the short message through the SMS-GMSC/SMS-IWMSC Sent to the appropriate PSAP; Step 812 to Step 815, the PSAP returns a confirmation message of the short message format to the E-IP-SM-GW; Step 816 to step 818, the E-IP-SM-GW returns an acknowledgement report of the short message format into an acknowledgement report of the SIP message format and returns it to the user UE; Step-Step 819~Step 4 821, the UE to the E-IP-SM -GW returns 200 OK to confirm. The request address in the emergency message request in this embodiment is the number of the emergency short message center, and the number causes the visited network to no longer route the emergency message request back to the user's home network, but processes it in the local network to implement an emergency. The short message function is convenient for users to use, which improves the performance of the system. Embodiment 5 FIG. 9 is a structural block diagram of an implementation system of an emergency short message according to an embodiment of the present invention. The system includes: a P-CSCF 902, configured to receive an emergency message request from a roaming user, and parse from the emergency message request. When the obtained request address is the number of the emergency short message center, the emergency message request is forwarded to the E-CSCF 904;

The E-CSCF 904 is connected to the P-CSCF 902, and is configured to insert the address of the corresponding public safety answering center PSAP into the emergency message request according to the location information of the user, and pass the emergency IP short message gateway E-IP- The SW-GW converts the emergency message request into an emergency short message. The short message center number in the emergency short message is the number of the emergency short message center, and the called number is the address of the PSAP, and the emergency short message is forwarded to the emergency short message center. The number of the emergency short message center may be sent to the user according to the method corresponding to FIG. 5 or FIG. 6. The corresponding PSAP refers to the PSAP corresponding to the address of the user. The PSAP should be as close as possible to the user. The address of the user can be obtained by querying the LRF. At this time, the PSAP can be allocated by the LRF; or, the user is The emergency message request carries the location information of the user, and the location information is used to indicate the address of the user, so that the message E-CSCF 904 can obtain the address of the user by querying the emergency message. At this time, the PSAP can be determined by the E-CSCF. The user's address is selected. Preferably, the E-CSCF 904 includes: a first E-CSCF and an E-IP-SM-GW, where the first E-CSCF is configured to obtain an address of the corresponding PSAP according to the location information of the user, and insert the In the emergency message request, and forwarded to the E-IP-SM-GW; the E-IP-SM-GW is set to convert the emergency message request into an emergency short message, wherein the called number, that is, the emergency call number, is changed to the PSAP Address, and forward the emergency short message to the emergency short message center. Subsequent forwarding processing is completed by the emergency short message center. Preferably, the system further comprises a mobility management network element configured to provide the number of the emergency short message center to the user in a user initiated attach procedure. FIG. 10 is a structural block diagram showing an implementation system of another emergency short message according to an embodiment of the present invention, which includes a P-CSCF 1002, an E-CSCF/E-IP-SM-GW 1004, and an SMS-IWMSC 1006. Emergency Short Message Center 1008 and PS AP 1010;

The P-CSCF 1002 is configured to receive an emergency message request from the roaming user, and when determining that the request address of the emergency message request is the number of the emergency short message center, forward the emergency message request to the E-CSCF/E-IP-SM- GW 1004;

An E-CSCF/E-IP-SM-GW 1004, connected to the P-CSCF 1002, configured to insert the address of the corresponding public safety answering center PSAP into the emergency message request according to the location information of the user, and The emergency message request is converted into an emergency short message, wherein the short message center number in the emergency short message is the number of the emergency short message center, and the called number is the address of the PSAP, and the emergency short message is forwarded to the emergency short message center. The address of the PSAP of this embodiment is the address of the PSAP 1010; the SMS-IWMSC 1006 is configured to send the emergency short message from the E-CSCF/E-IP-SM-GW 1004 to the emergency short message center 1008; the emergency short message center 1008, connected to the E-CSCF/E-IP-SM-GW 1004, configured to forward the emergency short message to the PSAP1010 according to the address of the PSAP;

The PSAP 1010 is connected to the emergency short message center 1008 and is configured to receive and respond to the emergency short message described above. The emergency call center 1008 in this embodiment may be a separate device, or may be set on a short message call center in the visited network; if the emergency short message center 1008 is set on the short message center of the visited network, the emergency short message The number of the center 1008 may be a combination of the number of the short message center and a preset emergency identity. The E-CSCF/E-IP-SM-GW in the visited network shown in Figure 10 has the functions of E-CSCF and E-IP-SM-GW, that is, E-CSCF and E-IP-SM-GW are set on the same network. On the E-CSCF/E-IP-SM-GW; in actual application, the E-CSCF and the E-IP-SM-GW can also be set on two different network elements respectively. In this case, E- The CSCF and the E-IP-SM-GW function as follows: The E-CSCF is configured to modify the emergency call number in the emergency message request to the address of the PSAP corresponding to the user's address, and forward it to the E-IP-SM-GW; -IP-SM-GW, used to receive emergency The information request converts the emergency message request into an emergency short message and sends an emergency short message to the SMS-IWMSC. The request address in the emergency message request in this embodiment is the number of the emergency short message center, and the number causes the visited network to no longer route the emergency message request back to the user's home network, but processes it in the local network to implement an emergency. The short message function is convenient for users to use, which improves the performance of the system. As can be seen from the above description, the present invention achieves the following technical effects: The request address in the emergency message request in the above embodiment is the number of the emergency short message center, and the number causes the visited network to no longer route the emergency message request. It is returned to the user's home network, but is processed in the local network to implement the emergency short message service. At the same time, the above solution does not require major modifications to the existing IMS architecture, and only needs to be deployed in the network to achieve an emergency short The sending of the message. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

1. An implementation method for an emergency short message, including:

The proxy session control function entity P-CSCF receives the emergency message request from the roaming user, and forwards the emergency message request to the emergency session control function when the request address parsed from the emergency message request is the number of the emergency short message center Entity E-CSCF; the E-CSCF inserts the address of the corresponding public safety response center PSAP into the emergency message request according to the location information of the user, and passes the emergency IP short message gateway E-IP- The SW-GW converts the emergency message request into an emergency short message, where the short message center number in the emergency short message is the number of the emergency short message center, and the called number is the address of the PSAP, and the forwarding is performed. Emergency short message to the emergency short message

2. The method according to claim 1, wherein the proxy session control function entity P-CSCF further comprises: before receiving the emergency message request from the roaming user:

Visiting the network to know that the user roams to the visited network;

The number of the emergency short message center is provided to the user.

3. The method according to claim 2, wherein the providing the number of the emergency short message center to the user comprises: the mobility management network element of the visited network in the user initiated attach process, The number of the emergency short message center is provided to the user.

The method according to claim 2, wherein the providing the number of the emergency short message center to the user comprises: after the user accessing the cell by the base station of the cell of the visited network, The number of the emergency short message center is provided to the user via a broadcast channel.

The method according to claim 1, wherein the short message center number and the called number of the short message format package in the emergency message request are respectively the number of the emergency short message center and the emergency call number.

The method according to claim 1, wherein the location information of the user is obtained by querying an address server LRF, and the corresponding PSAP is allocated by an LRF.

The method according to claim 1, wherein the emergency message request carries location information of the user, and the corresponding PSAP is selected by the E-CSCF according to the location information of the user. .

8. The method according to claim 1, wherein the E-IP-SM-GW is set in the E-CSCF, and the emergency message request is converted by an E-IP-SW-GW. The emergency short message is: converting the emergency message request into an emergency short message by the E-CSCF.

The method according to any one of claims 1-8, wherein the emergency short message center is set on a short message center of the visited network, and the number of the emergency short message center is the short message center a combination of a number and an emergency identifier; or, the emergency short message center is an independent device.

10. An implementation system for emergency short messages, including:

The proxy session control function entity P-CSCF is configured to receive an emergency message request from the roaming user, and forward the emergency message request to the emergency when the request address parsed from the emergency message request is the number of the emergency short message center Session control function entity E-CSCF;

The E-CSCF is configured to insert an address of the corresponding public safety answering center PSAP into the emergency message request according to the location information of the user, and pass the emergency IP short message gateway E-IP-SW-GW The emergency message request is converted into an emergency short message, wherein the short message center number in the emergency short message is the number of the emergency short message center, the called number is the address of the PSAP, and the emergency short message is forwarded to The emergency short message center.

The system according to claim 10, wherein the system further comprises: a mobility management network element, configured to provide the number of the emergency short message center to the user in an attach process initiated by the user user.