WO2011147329A1

WO2011147329A1 - Method and system for distributing public safety answer points to emergency session

Info

Publication number: WO2011147329A1
Application number: PCT/CN2011/074812
Authority: WO
Inventors: 李志军; 谢宝国; 朱春晖; 邹常乐
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-05-28
Filing date: 2011-05-27
Publication date: 2011-12-01
Also published as: CN102263779A

Abstract

A method and system for distributing Public Safety Answer Points (PSAP) to an emergency session are disclosed in the present invention, in which the method comprises that: a network side or terminal stores a first PSAP distributed to an emergency session request of the terminal; during an appointed time, after receiving a next emergency session request from the terminal, the network side distributes the first PSAP to the next emergency session request; the terminal utilizes the first PSAP to perform the next emergency session. Through the present invention in which a network side or terminal stores a PSAP distributed to an emergency session request of the terminal, a problem that continuity of the emergency session can not be ensured when a User Equipment (UE) is moving is solved, and the effect for improving performance of a system is approached.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a public safety answering point (PSAP), which may also be called a public safety answering point (PSAP). Method and system for an emergency communication reception center). Background technique

The IP Multimedia Subsystem (IMS) is the core of the new generation communication network. Its distinctive feature is the use of the Session Initiation Protocol (SIP) system, which is independent of access and has multiple media services. Control functions are separated from bearer capabilities, call and session separation, application and service separation, service and network separation, and convergence of mobile and Internet services. Due to the fact that IMS is independent of access, the emergency call (EMC) service under IMS can be built on the general packet radio service (GPRS) network and the system architecture evolution (SAE) network. Provide unified emergency session control. A schematic diagram of a network architecture in which a user equipment (UE) in a prior art performs an EMC service by accessing an SAE network. As shown in FIG. 1, the architecture includes: a SAE network part, and a policy charging control (PCC). Part, Location, and Location Service (LCS) and IMS Emergency Services. The SAE network part is used to provide the underlying bearer management and mobility management functions. The network elements of the part mainly include: an enhanced radio base station (eNodeB), a mobility management entity (MME, Mobility Management Entity), and a system long-term evolution gateway. (SAE GW, System Architecture Evolution Gateway). The SAE GW is a functional entity of the user plane, and is used for data path processing of the user plane, and is divided into a service gateway (S-GW, Serving GW) and a packet data network gateway (P-GW, Packet Data Network GW).

The PCC part is used to establish effective policy and charging control in the underlying bearer layer and the upper layer service layer. The network elements in this part mainly include: Policy and Charging Rules (PCRF, Policy and Charging Rules) Function) Entity and Policy and Charging Enforcement Function (PCEF) entity.

The LCS part is used to provide the location service and the address of the Public Safety Access Point (PSAP) for the emergency session. The network elements of the part mainly include: a Location Require Function (LRF) entity and a Gateway Mobile Location Center ( GMLC, Gateway Mobile Location Center).

The IMS emergency service part is used to control and process the session of the emergency session. The network elements of the part mainly include: a Home Subscriber Server (HSS) and a Call Session Control Function (CSCF). The HSS mainly manages the user's subscription data and is located in the home network. The CSCF is the core network element that controls the session process, including: Proxy CSCF (P-CSCF, Proxy-CSCF), Query CSCF (I-CSCF, Interrogating-CSCF) J-CSCF (S-CSCF, Serving-CSCF), Emergency CSCF (E-CSCF, Emergency-CSCF). The E-CSCF is a session control center of an emergency session, which determines which public safety answering point PSAP the emergency session is routed to. In the related art, the terminal UE initiates an IMS emergency session through GPRS/EPS, and experiences one of accessing the network, establishing a bearer and obtaining an IP address, discovering a P-CSCF, initiating an emergency session, and routing an emergency session to the PSAP. Series process. Referring to FIG. 2, a method for initiating an IMS emergency session after a GPRS/EPS access in a related art, the method includes the following steps: Step S201: A UE initiates an emergency session request, and an emergency session request is routed to an E-CSCF; S202. After receiving the emergency session request of the UE, the E-CSCF initiates a location query request to the LRF, queries the location information of the UE, and requests the LRF to allocate an appropriate PSAP. Step S203: The LRF queries the UE from the location service function entity (such as LCS). Location information, and the LRF selects a suitable PSAP from the configured PSAPs according to the obtained location information of the UE according to the location; Step S204, the LRF returns a location query response to the E-CSCF, and carries the current location information of the UE. And the PSAP selected according to the location; Step S205, the E-CSCF routes the emergency session request to the PSAP; Step S206, the PSAP and the UE complete the subsequent emergency session process. There are usually multiple PSAPs in the network, each of which has its jurisdiction, that is, each PSAP corresponds to a specific location area. In the process shown in FIG. 2, the LRF selects an appropriate PSAP according to the current location information of the UE. When the UE moves, since the current location of the UE changes, the LRF may select and The previous emergency session has a different PSAP. Since the emergency session is not limited to voice calls, in some special cases (such as deaf people), emergency sessions can be performed through SMS service and IMS message service. However, the inventors have found that the related art allocates different PSAPs of multiple emergency sessions of the UE after the UE moves, resulting in failure to maintain continuity of emergency services. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method and system for assigning a public safety answering point to an emergency session to at least solve the above problems. According to an aspect of the present invention, a method for allocating a public safety answering point for an emergency session is provided, including: a network side or a terminal saves a first PSAP to which an emergency session request of a terminal is allocated; After the next emergency session request of the terminal, the first PSAP is allocated for the next emergency session request; the terminal uses the first PSAP to perform the next emergency session. The network side location request function entity LRF saves the first PSAP; after receiving the next emergency session request, the network side allocates the first PSAP for the next emergency session request, including: emergency call session control function entity After receiving the next emergency session request, the E-CSCF initiates a location query request to the LRF. The location query request requires the LRF to allocate a PSAP to the terminal. After receiving the location query request, the LRF queries the current location information of the terminal. During the validity period of the first PSAP, the LRF allocates a first PSAP to the terminal, and sends a location query response to the E-CSCF, where the location query response carries the current location information of the terminal and the first PSAP; the E-CSCF will request the next emergency session. Routed to the first PSAP. The E-CSCF on the network side saves the first PSAP. After receiving the next emergency session request, the network side allocates the first PSAP for the next emergency session request in the specified time. After the next emergency session request, it is determined that the first PSAP routes the next emergency session request to the first PSAP within the valid time. The first PSAP to which the emergency session request of the terminal save terminal is allocated includes: the terminal receives a session establishment message from the E-CSCF, the session establishment message carries the first PSAP allocated by the terminal emergency session request, and the terminal saves the first PSAP; After receiving the next emergency session request from the terminal, the network side allocates the first PSAP for the next emergency session request, including: the terminal initiates the next emergency session request, and the next emergency session request carries the first PSAP; the E-CSCF receives After the next emergency session request of the terminal, it is determined that the first PSAP routes the next emergency session request to the first PSAP within the valid time. The routing of the next emergency session request to the first PSAP includes: if the location query request is not required to be sent to the LRF, the E-CSCF directly routes the next emergency session request to the first PSAP; if a location query request needs to be initiated to the LRF, The E-CSCF sends a location query request to the LRF. The location query request does not indicate that the LRF allocates a PSAP to the terminal. After receiving the current location information of the terminal returned by the LRF, the E-CSCF routes the next emergency session request to the first PSAP. The PSAP registration entity on the network side saves the identifier of the first PSAP and the terminal; and allocates the first PSAP for the next emergency session request: when the E-CSCF or the LRF allocates the PSAP for the next emergency session request, initiates a query to the PSAP registration entity. The request, based on the result of the query request, assigns a first PSAP to the next emergency session request. The PSAP registration entity of the network side saves the identifiers of the first PSAP and the terminal, where the LSAP sends a PSAP registration request to the PSAP registration entity in the network side after the first PSAP is allocated for the terminal emergency session request, and the PSAP registration request carries the identifier of the terminal. And the first PSAP, the PSAP registration entity saves the identifier of the terminal and the first PSAP; assigns the first PSAP to the next emergency session request includes: LRF sends a PSAP query request to the PSAP registration entity before assigning the PSAP to the next emergency session request of the terminal The PSAP query request carries the identifier of the terminal; the PSAP registration entity determines that the terminal has assigned the first PSAP, and the first PSAP returns the first PSAP to the LRF within the valid time; the LRF allocates the first PSAP for the next emergency session request. . The PSAP registration entity of the network side saves the identifiers of the first PSAP and the terminal, where the E-CSCF sends a PSAP registration request to the PSAP registration entity in the network side, and the PSAP registration request carries the identifier of the terminal and the first allocation for the terminal emergency session request. a PSAP, the PSAP registration entity stores the identity of the terminal and the first PSAP; assigning the first PSAP to the next emergency session request includes: the E-CSCF sends a PSAP query request to the PSAP registration entity, and the PSAP query request carries the identity of the terminal; It is determined that the terminal has been assigned the first PSAP, and the first PSAP returns the first PSAP to the E-CSCF within the valid time; the E-CSCF routes the next emergency session request to the first PSAP. Before the E-CSCF sends the PSAP query request to the PSAP registration entity, the method further includes: the E-CSCF receives the second PSAP allocated from the LRF for the next emergency session request of the terminal, and the PSAP query request carries the second PSAP. The PSAP registration entity of the network side saves the identifiers of the first PSAP and the terminal includes: After the E-CSCF routes the terminal emergency session request to the first PSAP, the first PSAP sends the first PSAP registration request to the PSAP registration entity in the network side. The first PSAP registration request carries the identifier of the terminal and the first PSAP, and the PSAP registration entity saves the identifier of the terminal and the first PSAP; the foregoing assigning the first PSAP to the next emergency session request includes: the E-CSCF receives the terminal from the LRF. After the next emergency session requests the assigned second PSAP, the next emergency session request is routed to the second PSAP; the second PSAP sends a second PSAP registration request to the PSAP registration entity, and the second PSAP registration request carries the identity of the terminal and the second PSAP; The PSAP registration entity determines that the first PSAP has been assigned to the terminal, and the first PSAP is within the valid time, ^! The first PSAP is returned to the second PSAP; the second PSAP routes the next emergency session request to the first PSAP, or the second PSAP returns an emergency session redirect message to the E-CSCF, the redirect message carries the first PSAP, by the E - The CSCF routes the next emergency session request to the first PSAP. According to another aspect of the present invention, a system for assigning a public safety answering point to an emergency session is provided, comprising: a network side device and a terminal; a network side device or terminal, configured to save a first PSAP to which an emergency session request of the terminal is allocated The network side device is further configured to allocate a first PSAP for the next emergency session request after receiving the next emergency session request of the terminal within a specified time; the terminal is further configured to use the first PSAP for the next emergency session. The network side device includes a location request function entity LRF, an emergency call session control function entity E-CSCF, an LRF, which is set to save the first PSAP, and an E-CSCF, which is set to receive the next emergency session request of the terminal, and then initiates to the LRF. The location query request, the location query request requires the LRF to allocate a PSAP to the terminal; the LRF is further configured to query the current location information of the terminal after receiving the location query request of the E-CSCF; if it is determined that the first PSAP is within the valid time, The terminal allocates the first PSAP, and sends a location query response to the E-CSCF, where the location query response carries the current location information of the terminal and the first PSAP; the E-CSCF is further configured to route the next emergency session request after receiving the location query response. Give the first PSAP. The network side device includes an E-CSCF; the E-CSCF is configured to save the first PSAP, and after receiving the next emergency session request of the terminal, determine that the first PSAP routes the next emergency session request to the first time within the valid time. A PSAP. The network side device includes an E-CSCF, and is configured to send a session establishment message to the terminal, where the session establishment message carries the first PSAP allocated by the terminal emergency session request; the terminal is configured to save the first PSAP, and initiate the next emergency session request, The next emergency session request carries the first PSAP; the E-CSCF is further configured to: after receiving the next emergency session request of the terminal, determine that the first PSAP routes the next emergency session request to the first PSAP within the valid time. The network side device includes: a PSAP registration entity, configured to save the identifier of the first PSAP and the terminal; and when receiving the query request, determining that the terminal has been assigned the first PSAP, and the first PSAP is within the valid time, A PSAP is returned to the E-CSCF; the network side device further includes: an E-CSCF or an LRF, configured to initiate a query request to the PSAP registration entity when the PSAP is allocated for the next emergency session request of the terminal, according to the result of the query request is the next The emergency session request allocates the first PSAP. Through the invention, the PSAP for storing the emergency session request of the terminal is saved on the network side or the terminal, which solves the problem that the continuity of the emergency session cannot be guaranteed when the UE moves, thereby achieving the effect of improving the performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a schematic diagram of a network architecture for performing EMC services according to the related art; FIG. 2 is a flowchart of a method for initiating an IMS emergency session according to the related art; FIG. 3 is a PSAP for assigning emergency sessions according to an embodiment of the present invention; FIG. 4 is a flowchart of a method for saving a PSAP allocated to a UE by an LRF or an E-CSCF according to Embodiment 1 of the present invention; FIG. 5 is a diagram showing that an LRF according to Embodiment 1 of the present invention allocates the same PSAP to a UE. FIG. 6 is a flowchart of a method for an E-CSCF to allocate the same PSAP to a UE according to Embodiment 2 of the present invention; FIG. 7 is a system structure of an emergency session after introducing an SAP registration entity according to Embodiment 3 of the present invention; block diagram; FIG. 8 is a flowchart of a method for allocating a PSAP for an emergency session according to Embodiment 3 of the present invention; FIG. 9 is a flowchart of a method for allocating a PSAP for an emergency session according to Embodiment 4 of the present invention; FIG. FIG. 11 is a flowchart of a method for allocating a PSAP for an emergency session according to Embodiment 6 of the present invention; FIG. 12 is a flowchart of a method for allocating a PSAP according to Embodiment 6 of the present invention; A block diagram of the system structure for assigning PSAPs to emergency sessions. 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. As shown in Figure 1, the SAE network that performs the emergency session service includes network elements such as E-CSCF, PSAP, and LRF. In the SAE network, a PSAP registration entity can also be set up. The PSAP registration entity is used to store terminal identifiers and terminal emergency. The PSAP used by the session. The connection relationship between the network elements follows the provisions of the relevant communication standards. The various embodiments of the present invention are described below based on the SAE network. FIG. 3 is a flowchart of a method for allocating a PSAP for an emergency session according to an embodiment of the present invention. The method includes the following steps: Step S302: The network side or the terminal saves the first session of the emergency session request of the terminal. The PSAP; wherein the network side storing the first PSAP may be an E-CSCF or an LRF, or may be a PSAP registration entity added in the network; the first PSAP that is allocated to save the terminal's emergency session request is saved. The correspondence between the terminal and the first PSAP, and the correspondence may be represented by the identifier of the terminal and the first PSAP identifier (such as a PSAP address). Step S304, after receiving the next emergency session request of the terminal, the network side allocates a first PSAP for the next emergency session request within a specified time; when the next emergency session request of the terminal is not within the specified time, the network side Reassigning the PSAP to the terminal, and saving the reassigned PSAP as the first PSAP; Step S306, the terminal uses the first PSAP for the next emergency session. When the PSAP is allocated to the UE, the related technologies are allocated based on the current location of the UE. In the embodiment of the present invention, when the PSAP used for the subsequent emergency session is allocated to the UE, if the correlation between the two emergency sessions is relatively large, that is, If the time interval is short, the subsequent emergency session is assigned the same PSAP as the previous emergency session to ensure the continuity of the emergency session. Usually, this specified time is set by the operator according to the operation strategy. In this embodiment, by storing the PSAP allocated by the emergency session request of the terminal on the network side or the terminal, the emergency session of the terminal can be anchored to the PSAP within a specified time, thereby solving the problem that the emergency session cannot be guaranteed when the UE moves. The problem of continuity improves the performance of the system. Embodiment 1 In this embodiment, after the LRF allocates the PSAP to the UE, the LRF or the E-CSCF saves the PSAP locally for a certain period of time. After the UE initiates the emergency session again, the LRF or the E-CSCF may directly select the PSAP. The PSAP serves the UE. 4 is a flowchart of a method for saving an LSAP allocated by an LRF or an E-CSCF to a UE, where the method includes the following steps: Step S401: The UE initiates an emergency session request, and the emergency session request is routed to the E-CSCF; Step S402, E After receiving the emergency session request, the CSCF initiates a location query request to the LRF, and requests the LRF to allocate a PSAP to the UE. Step S403, the LRF queries the current location information of the UE from the location server (such as the LCS system), and allocates a suitable location according to the location information. PSAP. Here, it is assumed that the currently assigned PSAP is PSAP1; optionally, the LRF locally stores the PSAP1 allocated for the UE, and sets a time limit during which the UE can continue to use the PSAP1. Step S404, the LRF sends a location query response to the E-CSCF, where the location query response carries the current location information of the UE, the PSAP allocated to the UE (here, PSAP1); Step S405, the E-CSCF receives the location query sent by the LRF. After the response, the PSAP1 allocated for the UE is locally saved, and a deadline is set, during which the UE can continue to use the PSAP1; this step 4 is an optional step. Step S406, the E-CSCF routes the emergency session request to the PSAP 1; Step S407, a subsequent emergency session processing process is performed between the PSAP1 and the UE. In the flow shown in Figure 4, both the LRF and the E-CSCF can locally save the PSAP address assigned to the UE, and further set a time limit. If the PSAP saved beyond this period is invalid, the PSAP should be reassigned to the UE. Based on the method shown in FIG. 4, after the UE moves, when the second emergency session service is initiated, the LRF allocates the same PSAP method to the UE as the first emergency session service. Referring to FIG. 5, the method includes the following steps: Step S501: The UE initiates an emergency session request, and the emergency session request is routed to the E-CSCF. Step S502: After receiving the emergency session request, the E-CSCF initiates a location query request to the LRF, and requests the LRF to allocate a PSAP for the UE. Step S503 The LRF performs a location query process to query the current location information of the UE, and the LRF performs a PSAP allocation process to allocate a suitable PSAP to the UE. In this step, if the LRF stores information that previously assigned the PSAP to the UE, that is, PSAP 1 And the PSAP1 is still in the valid time, then the LRF can directly use the PSAP1 without reassigning the PSAP, even if it may happen that the PSAP2 should be allocated to the UE according to the current location of the UE, and the PSAP1 is also used. Step S504, the LRF sends a location query response to the E-CSCF, where the current location information of the UE and the PSAP allocated to the UE (PSAP1 in this embodiment) are carried; Step S505, the E-CSCF routes the emergency session request to the PSAP1; Step S506 The subsequent emergency session processing process is performed between the PSAP1 and the UE. In this embodiment, the LRF saves the PSAP information previously allocated for the UE, and the interval between the emergency session and the last emergency session is within the time limit, so the LRF is still Assigning the PSAP to the UE solves the problem that the continuity of the emergency session cannot be guaranteed when the UE moves, and improves the performance of the system. Embodiment 2 Based on the method shown in FIG. 4, after the UE moves, when the second emergency session service is initiated, the E-CSCF allocates the same PSAP method to the UE as the first emergency session service, as shown in FIG. Including the following steps: Step S601: The UE initiates an emergency session request, and the emergency session request is routed to the E-CSCF. Step S602: After receiving the emergency session request, the E-CSCF initiates a location query request to the LRF, and requests the LRF to allocate a PSAP for the UE. Step S603 The LRF performs a location query process to query the current location information of the UE. At the same time, the LRF performs the PSAP allocation process to allocate the appropriate PSAP to the UE. In this embodiment, the LRF is used as the UE PSAP2 for the first time; in step S604, the LRF sends a location query response to the E-CSCF, where the current location information of the UE and the PSAP allocated to the UE (JP匕, ie, PSAP2) are carried; S605, the E-CSCF receives the location query response, and obtains the PSAP2. In this step, since the E-CSCF saves the PSAP information previously allocated for the UE, that is, PSAP1, and the interval between the emergency session and the last emergency session is Within the time limit, the E-CSCF can ignore the PSAP2 returned by the LRF and still allocate PSAP1 to the UE. Step S606, the E-CSCF routes the emergency session request to the PSAP 1; Step S607, the subsequent emergency session processing process is performed between the PSAP1 and the UE; in the flow shown in FIG. 6, the E-CSCF saves the previously allocated for the UE. PSAP information, and within the time limit, the UE initiates the next emergency session service, so the E-CSCF still allocates the PSAP for the UE. Preferably, if the E-CSCF does not need to query the LRF for the location information of the UE, the E-CSCF can directly use the held PSAP information, ie, PSAP1, to route the emergency session request to the PSAP1; if the E-CSCF needs to query the LRF The location information of the UE, the E-CSCF may not indicate the LRF allocation PSAP in the location query request, so that the LRF does not allocate the PSAP to the UE, and the E-CSCF uses the previously saved PSAP information to route the emergency session. In this embodiment, the E-CSCF saves the PSAP information previously allocated for the UE, and the interval between the emergency session and the last emergency session is within a time limit, so the E-CSCF still allocates the PSAP for the UE, and the solution is resolved. When the UE moves, the problem of emergency session continuity cannot be guaranteed, and the performance of the system is improved. In the foregoing Embodiment 1 and Embodiment 2, the PSAP information previously allocated for the UE may be saved on the LRF/E-CSCF, so that the previously saved PSAP is allocated to the UE when the UE initiates the emergency session, and the emergency session is guaranteed. Continuity. Embodiment 3 This embodiment introduces a PSAP registration entity in an SAE network. When a PSAP is allocated to a UE, a query is initiated to the PSAP registration entity. If the PSAP registration entity does not save the PSAP allocated before the UE, the PSAP is allocated to the UE. Save to the PSAP registration entity. For example, the PSAP registration entity saves the PSAP of the terminal's emergency session request and the identifier of the terminal, and when the E-CSCF or LRF allocates the PSAP for the next emergency session request of the terminal, initiates a query request to the PSAP registration entity, according to the query. The result of the request is the next emergency session request

PSAP. FIG. 7 is a block diagram showing the system structure of an emergency session after the introduction of a PSAP registration entity according to an embodiment of the present invention, in which LRF, E-CSCF, PSAP are both possible and PSAP Registration Entity, PRE The establishment of the interface Pr, such as establishing a Prl interface between the E-CSCF and the PRE, establishing a Pr2 interface between the LRF and the PRE, and establishing a Pr3 interface between the PSAP and the PRE. On these Pr interfaces, the PSAP is queried for the PSAP assigned to the UE, and the PSAP is registered as the PSAP assigned to the UE. In the case of roaming, if the PRE entity is deployed in the home network, the UE can still access the same PSAP when switching to a different network. If the PRE entity is deployed in the visited network, it can only ensure that the UE is still connected to the same PSAP when moving within the visited network. In addition, as a logical functional entity, PRE can be considered for independent deployment. It can also be considered for functional entities such as LRF and E-CSCF. If the PRE is deployed on the home network, the PRE can be deployed on the HSS. FIG. 8 is a flowchart of a method for allocating a PSAP for an emergency session according to an embodiment of the present invention. The method for the LRF and the PRE to exist in the method includes the following steps: Step S801: The UE initiates an emergency session request, and the emergency session request is Routing to the E-CSCF; Step S802, after receiving the emergency session request, the E-CSCF initiates a location query request to the LRF, and requests the LRF to allocate a PSAP for the UE; Step S803, the LRF performs a location query process, and queries the current location information of the UE, and the LRF performs a PSAP allocation process to allocate a suitable PSAP to the UE. For example, according to the current location information of the UE, the LRF allocates PSAP2 to the UE; Step S804, LRF Sending a PSAP registration request to the PRE (PSAP registration entity), carrying the target i of the UE and the PSAP currently assigned to the UE (ie, PSAP2); Step S805, the PRE is updated to the PSAP allocated by the UE; specifically, in this step, the PRE更新 Update the PSAP assigned to the UE with the following policy:

A) If the PRE currently stores a PSAP for the UE, such as PSAP1, and the PSAP1 is still within the set valid time, the PRE sets the PSAP currently allocated for the UE to still be PSAP1. B) If the PRE does not currently save a PSAP for the UE, or if a PSAP has been previously saved, such as the PS API, but the PS API has exceeded the set valid time period, the PRE believes that the PSAP should be re-registered for the UE, so The PRE obtains the PSAP (ie, PSAP2) provided by the LRF to the PRE, and the PSAP2 updates the PSAP information allocated to the UE. In step S806, the PRE returns a registration response to the LRF. In the registration response, the PRE carries the PSAP information currently allocated by the UE. Specifically, in this step, if the rule is based on the rule A in step S805, the PRE sets the current allocation of the UE. If the PSAP is PSAP1, then the PRE returns to PSAP1; if the PRE is set according to the rule B) in step S805, the PRE sets the PSAP currently allocated by the UE to be PSAP2, then the PRE returns to PSAP2; Step S807, the LRF receives the PSAP registration response returned by the PRE Obtaining a PSAP carried therein, and returning a location query response to the E-CSCF, including the current location information of the UE; and, in the location query response, including the PSAP returned by the PRE; step S808a, step S808b, and E-CSCF according to the slave LRF The obtained PSAP routes the emergency session request to the corresponding PSAP; Step S809, the subsequent emergency session processing process is performed between the PSAP and the UE. The process shown in FIG. 8 describes the process in which the LRF registers with the PRE and queries the PSAP allocated to the UE. In the process of performing registration and querying by the LRF to the PRE, the LRF can be implemented by using only one message. The implementation method may have the following modifications. The LRF first queries the PSAP allocated to the UE from the PRE. If the PSAP currently allocated for the UE is obtained from the PRE, the PSAP is directly used. The PRE obtains the PSAP allocated for the UE, and the LRF selects an appropriate PSAP according to the location information of the UE, and saves it to the PRE. In this embodiment, the PSAP is registered by the LRF to the PSAP that is registered as the UE. When the next emergency session request is close to the last emergency session request, the PRE updates the newly allocated PSAP of the LRF, so that the emergency session is two times. Requests can be assigned the same PSAP, ensuring continuity of emergency sessions and improving system performance. Embodiment 4 This embodiment provides a method for allocating a PSAP for an emergency session. The method has an E-CSCF and a PRE existing interface, and the E-CSCF queries the PRE and registers the PSAP allocated to the UE as an example. Similar to the flow shown in FIG. 8 in Embodiment 3, referring to FIG. 9, steps S901 to S904 in the method are the same as steps S801 to S804, and steps S907 to S909 are the same as steps S807 to S809. Therefore, in step S905, after obtaining the PSAP (ie, PSAP2) from the location query response returned by the LRF, the E-CSCF performs the PSAP registration process with the PSAP2 to the PRE. Using the method shown in FIG. 8, the PRE is updated to the PSAP assigned by the UE and returned to the E-CSCF, as in step S906 and step S907, so that the E-CSCF routes the emergency session request to the appropriate PSAP. Similarly, the flow of FIG. 9 also has a variant embodiment, that is, the PSAP query and registration process can be split into multiple messages by one message, but the basic principle is unchanged. In this embodiment, the PSAP is registered to the PRE by the E-CSCF, and when the next emergency session request is close to the last emergency session request, the PRE updates the PSAP, so that the two emergency session requests can be performed before and after. Assigning the same PSAP ensures continuity of emergency sessions and improves system performance. EMBODIMENT 5 This embodiment provides a method for allocating a PSAP for an emergency session. The method is described by using an interface between the PSAP and the PRE, and querying the PRE and registering the PSAP allocated to the UE. Referring to FIG. 10, the method includes the following. Step 4: Step S1001, the E-CSCF receives an emergency session request of the UE; Step S 1002, the E-CSCF obtains the PSAP of the current emergency session request of the UE from the LRF as PSAP2, and the E-CSCF routes the emergency session request to the PSAP2; Step S1003, the PSAP2 initiates a PSAP registration process to the PRE, that is, the UE The identifier and the PSAP2 are sent to the PRE; Step S1004, after receiving the registration request of the PSAP2, the PRE updates the PSAP of the UE; Step S1005, the PRE determines that the UE has assigned the PSAP1 according to the identifier of the UE, and the PSAP1 is During the effective time, PSAP1 is returned to PSAP2; in steps S1004, S1005, and the method shown in FIG. 8, the PRF is updated to the PSAP allocated by the UE and returned to PSAP2. If the PSAP obtained by PSAP2 from the PSAP registration response returned by the PRE is not itself, for example, PSAP1, PSAP2 can perform the following process:

A) as step S 1006a, PSAP2 acts as a proxy, routing the current emergency session to PSAP1;

B) In step S 1006b1 to S 1006b2, PSAP2 returns an emergency session redirection message to the E-CSCF, and carries the PSAP 1 in the redirection message. When the E-CS CF receives the emergency session redirection message, the current emergency session request is sent. Routing to PSAP1; Step S1007, subsequent emergency session processing between the PSAP and the UE. The flow shown in Figure 10 is similar to the flow shown in Figures 4 and 8. The main difference is: If the LRF selects PSAP2 for the UE, when the E-CSCF routes the emergency session to PSAP2, PSAP2 initiates the PSAP registration process to the PRE, PRF Update the PSAP assigned to the UE and return it to PSAP2. If the PSAP obtained by PS AP2 from the PSAP registration response returned by the PRE is not itself, the current emergency session request is routed to the corresponding PSAP by the method in A) or B) above. In this embodiment, the PSAP registers the PSAP that is registered as the UE by the PSAP. When the next emergency session request is close to the last emergency session request interval, the PRE updates the PSAP, so that the two emergency session requests can be assigned the same time. The PSAP ensures continuity of emergency sessions and improves system performance. Embodiment 6 This embodiment provides a method for allocating a PSAP for an emergency session. The method is described by taking the example that the UE itself saves the allocated PSAP. Referring to FIG. 11, the method includes the following steps: Steps S1101 to S1105 are the same as steps S201 to S205, and are not described here. Compared with the normal emergency session establishment procedure, the improvement of this embodiment lies in the following steps: Step S1106, when the PSAP and the UE confirm the emergency When the session is established, the E-CSCF carries the PSAP information currently allocated for the UE in the session setup message sent to the UE, here PSAP1; Step S1107, after receiving the PSAP information, the UE saves the PSAP information locally, that is, saves PSAP1; Step S1108: When transmitting the subsequent emergency session request to the E-CSCF, the UE carries the previously saved PSAP information, that is, PSAP1. The E-CSCF will use the PS API to route emergency session requests to the PSAP1.

The E-CSCF will use the PS API to route emergency session requests to the PSAP1 including: If no location query request is required to be initiated to the LRF, the E-CSCF directly routes the current emergency session request to PSAP1; if a location query request needs to be initiated to the LRF The E-CSCF sends a location query request to the LRF. The location query request does not indicate that the LRF allocates a PSAP to the UE. After receiving the current location information of the UE returned by the LRF, the E-CSCF routes the current emergency session request to the PSAP1. Step S1109, a subsequent emergency session processing process is performed between the PSAP and the UE. Before the UE in this embodiment carries the saved PSAP information, it may first determine whether the saved PSAP is within the valid time. If yes, the PSAP information is carried, otherwise it is not carried, and the establishment of the emergency session is completed according to the relevant process; or, E After receiving the PSAP sent by the UE, the CSCF may first determine whether the PSAP is within the valid time. If yes, the current emergency session request is routed to the PSAP, otherwise the emergency session is established according to the related procedure. In this embodiment, after the UE initiates an emergency session for the first time, the network allocates a PSAP to the UE, and delivers the PSAP information to the UE during the post-session establishment process, and the UE saves the PSAP locally. When the UE initiates the subsequent emergency session, the UE carries the previously saved PSAP information to the E-CSCF, and the E-CSCF can use the PSAP provided by the UE to route the emergency session, so as to anchor multiple emergency sessions to the same PSAP. , to ensure the continuity of the emergency session. Embodiment 7 FIG. 12 illustrates a system for allocating a PSAP for an emergency session according to an embodiment of the present invention, including: a network side device 120 and a terminal 124; The network side device 120 or the terminal 124 is configured to save the first PSAP to which the emergency session request of the terminal 124 is allocated; the network side device 120 is further configured to: after receiving the next emergency session request from the terminal 124 within the specified time, the next P The emergency session request allocates a first PSAP; the terminal 124 is also arranged to use the first PSAP for the next emergency session. The network side device 120 may be an E-CSCF or an LRF, or may be a PSAP registration entity added in the network. The first PSAP is saved, and the corresponding relationship between the terminal and the first PSAP is saved. It is represented by the identity of the terminal and the first PSAP identifier (such as the PSAP address). By storing the PSAP allocated by the emergency session request of the terminal on the network side device or the terminal, the emergency session of the terminal can be anchored to the PSAP within a specified time, thereby solving the problem that the emergency session continuity cannot be guaranteed when the UE moves. The problem has improved the performance of the system. Preferably, the network side device includes an LRF and an E-CSCF; wherein the LRF is configured to save the first PSAP; the E-CSCF is configured to: after receiving the next emergency session request from the terminal 124, initiate a location query request to the LRF, The location query request requires the LRF to allocate a PSAP to the terminal 124;

The LRF is further configured to: after receiving the location query request of the E-CSCF, query the current location information of the terminal 124; if it is determined that the first PSAP is within the valid time, allocate the first PSAP to the terminal 124, and send a location query to the E-CSCF. In response, the location query response carries the current location information of the terminal 124 and the first PSAP; the E-CSCF is further configured to route the next emergency session request to the first PSAP after receiving the location query response. Preferably, the network side device 120 includes an E-CSCF; the E-CSCF is configured to save the first PSAP, and after receiving the next emergency session request of the terminal 124, determine that the first PSAP is within the valid time, and the next emergency session The request is routed to the first PSAP. Preferably, the network side device 120 includes an E-CSCF, configured to send a session establishment message to the terminal 124, the session establishment message carrying the first PSAP allocated by the terminal 124 emergency session request; the terminal 124 is configured to save the first PSAP, and initiate the next An emergency session request, the next emergency session request carries the first PSAP; the E-CSCF is further configured to receive the next emergency meeting of the terminal 124 After the request is made, it is determined that the first PSAP routes the next emergency session request to the first PSAP within the valid time. The network side device 120 includes: a PSAP registration entity, configured to save the identifiers of the first PSAP and the terminal 124; and when receiving the query request, determine that the terminal 124 has been assigned the first PSAP according to the identifier of the terminal 124, and the first PSAP The first PSAP is returned to the E-CSCF during the valid time; the network side device 120 further includes: an E-CSCF or an LRF, configured to initiate a query request to the PSAP registration entity when the PSAP is allocated for the next emergency session request of the terminal 124. And assigning a first PSAP to the next emergency session request according to the result of the query request. As can be seen from the above description, the PSAP of the emergency session request of the terminal is saved on the network side or the terminal, so that the emergency session of the terminal is anchored to the PSAP within a specified time. Furthermore, the problem that the continuity of the emergency session cannot be guaranteed when the UE moves is solved, and the performance of the system is improved. 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

1. A method for assigning a public safety answering point PSAP to an emergency session, comprising:

The network side or terminal saves the first PSAP to which the emergency session request of the terminal is allocated; after receiving the next emergency session request of the terminal, the network side allocates the next emergency session request request within a specified time. Said first PSAP;

The terminal uses the first PSAP for the next emergency session.

2. The method according to claim 1, wherein the location request function entity LRF on the network side saves the first PSAP;

After the network side receives the next emergency session request of the terminal, the first PSAP is allocated for the next emergency session request, including:

The emergency call session control function entity E-CSCF, after receiving the next emergency session request of the terminal, initiates a location query request to the LRF, where the location query request requires the LRF to allocate a PSAP to the terminal;

After receiving the location query request, the LRF queries the current location information of the terminal;

If it is determined that the first PSAP is within a valid time, the LRF allocates the first PSAP to the terminal, and sends a location query response to the E-CSCF, where the location query response carries the current location of the terminal Location information and the first PSAP;

The E-CSCF routes the next emergency session request to the first PSAP.

The method according to claim 1, wherein the E-CSCF on the network side saves the first PSAP;

After receiving the next emergency session request of the terminal, the E-CSCF determines that the first PSAP routes the next emergency session request to the first PSAP within a valid time.

The method according to claim 1, wherein the storing, by the terminal, the first PSAP that the emergency session request of the terminal is allocated comprises: the terminal receiving a session establishment message from the E-CSCF, The session establishment message carries a first PSAP allocated by the terminal emergency session request, and the terminal saves the first PSAP;

The terminal initiates a next emergency session request, and the next emergency session request carries the first PSAP;

After receiving the next emergency session request by the terminal, the E-CSCF determines that the first PSAP routes the next emergency session request to the first PSAP within a valid time. The method of claim 3 or 4, wherein routing the next emergency session request to the first PSAP comprises:

If the location query request is not required to be sent to the LRF, the E-CSCF directly routes the next emergency session request to the first PSAP;

If the location request request is initiated to the LRF, the E-CSCF sends a location query request to the LRF, where the location query request does not indicate that the LRF allocates a PSAP to the terminal; the E-CSCF receives the After the current location information of the terminal returned by the LRF, the next emergency session request is routed to the first PSAP. The method according to claim 1, wherein the PSAP registration entity on the network side saves the identifier of the first PSAP and the terminal;

Allocating the first PSAP for the next emergency session request includes:

When the E-CSCF or LRF allocates a PSAP for the next emergency session request, it initiates a query request to the PSAP registration entity, and the result of the query request allocates the first PSAP for the next emergency session request. The method according to claim 6, wherein the saving of the first PSAP and the terminal by the PSAP registration entity of the network side includes:

After the first PSAP is allocated to the terminal emergency session request, the LRF sends a PSAP registration request to the PSAP registration entity in the network side, where the PSAP registration request carries the identifier of the terminal and the first PSAP, the PSAP The registration entity saves the identifier of the terminal and the first PSAP;

Allocating the first PSAP for the next emergency session request includes: Before the PRF allocates the PSAP to the next emergency session request of the terminal, the PRF sends a PSAP query request to the PSAP registration entity, where the PSAP query request carries the identifier of the terminal;

The PSAP registration entity determines that the first PSAP has been allocated to the terminal, and the first PSAP returns the first PSAP to the LRF within a valid time;

The LRF allocates the first PSAP for the next emergency session request.

The method according to claim 6, wherein the saving of the first PSAP and the terminal by the PSAP registration entity of the network side includes:

The E-CSCF sends a PSAP registration request to the PSAP registration entity in the network side, where the PSAP registration request carries the identifier of the terminal and a first PSAP allocated for the terminal emergency session request, where the PSAP registration entity saves Describe the identifier of the terminal and the first PSAP;

Assigning the first PSAP to the next emergency session request includes: sending, by the E-CSCF, a PSAP query request to the PSAP registration entity, where the PSAP query request carries an identifier of the terminal;

The PSAP registration entity determines that the first PSAP has been allocated to the terminal, and the first PSAP returns the first PSAP to the E-CSCF within a valid time;

The E-CSCF routes the next emergency session request to the first PSAP.

9. The method according to claim 8, wherein, before the sending, by the E-CSCF, the PSAP query request to the PSAP registration entity, the method further comprises: the E-CSCF receiving a next emergency session from the LRF for the terminal Requesting an assigned second PSAP, the PSAP query request carrying the second PSAP.

After the E-CSCF routes the terminal emergency session request to the first PSAP, the first PSAP sends a first PSAP registration request to the PSAP registration entity in the network side, where the first PSAP registration request carries the terminal And the first PSAP, the PSAP registration entity saves the identifier of the terminal and the first PSAP;

Allocating the first PSAP for the next emergency session request includes: After receiving the second PSAP from the LRF for the next emergency session request of the terminal, the E-CSCF routes the next emergency session request to the second PSAP;

The second PSAP sends a second PSAP registration request to the PSAP registration entity, where the second PSAP registration request carries the identifier of the terminal and the second PSAP;

Determining, by the PSAP registration entity, that the first PSAP has been allocated to the terminal, and the first PSAP returns the first PSAP to a second PSAP within a valid time; the second PSAP will The next emergency session request is routed to the first PSAP, or the second PSAP returns an emergency session redirection message to the E-CSCF, the redirect message carrying the first PSAP, by the E-CSCF Routing the next emergency session request to the first PSAP.

11. A system for assigning a public safety answering point PSAP to an emergency session, comprising: a network side device and a terminal;

a network side device or terminal, configured to save a first PSAP to which the emergency session request of the terminal is allocated;

The network side device is further configured to allocate the first PSAP for the next emergency session request after receiving the next emergency session request of the terminal within a specified time;

The terminal is further arranged to use the first PSAP for the next emergency session.

The system according to claim 11, wherein the network side device comprises a location request function entity LRF, an emergency call session control function entity E-CSCF;

The LRF is set to save the first PSAP;

The E-CSCF is configured to: after receiving the next emergency session request of the terminal, initiate a location query request to the LRF, where the location query request requires the LRF to allocate a PSAP to the terminal;

The LRF is further configured to: after receiving the location query request of the E-CSCF, query the current location information of the terminal; if it is determined that the first PSAP is within a valid time, assign the first to the terminal a PSAP, and sending a location query response to the E-CSCF, where the location query response carries the current location information of the terminal and the first PSAP;

The E-CSCF is further configured to route the next emergency session request to the first PSAP after receiving the location query response.

13. The system according to claim 11, wherein: the network side device comprises an E-CSCF; the E-CSCF is configured to save the first PSAP, and after receiving the next emergency session request of the terminal Determining that the first PSAP routes the next emergency session request to the first PSAP within a valid time.

The system according to claim 11, wherein the network side device comprises an E-CSCF, configured to send a session establishment message to the terminal, where the session establishment message carries the first of the terminal emergency session request allocation PSAP;

The terminal is configured to save the first PSAP, and initiate a next emergency session request, where the next emergency session request carries the first PSAP;

The E-CSCF is further configured to: after receiving the next emergency session request of the terminal, determine that the first PSAP routes the next emergency session request to the first PSAP within a valid time.

The system according to claim 11, wherein the network side device comprises: a PSAP registration entity, configured to save the identifier of the first PSAP and the terminal; and when receiving the query request, determining that the The terminal has allocated the first PSAP, and the first PSAP returns the first PSAP to the E-CSCF within a valid time;

The network side device further includes: an E-CSCF or an LRF, configured to initiate a query request to the PSAP registration entity when the PSAP is allocated for the next emergency session request of the terminal, according to a result of the query request, the next one The emergency session request allocates the first PSAP.