WO2007107088A1

WO2007107088A1 - A handover method, arrangement and system for mobile management entity (mme)/service gateway

Info

Publication number: WO2007107088A1
Application number: PCT/CN2007/000837
Authority: WO
Inventors: Xiaolong Guo
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-03-15
Filing date: 2007-03-15
Publication date: 2007-09-27
Also published as: CN101039506B; CN101039506A

Abstract

A method for Mobile Management Entity (MME)/service gateway applied to the evolution network comprises: judging whether the current state of the source MME/service gateway served for UE before the handover meets the predetermined handover condition or not; selecting a object MME/service gateway, which is the MME/service gateway after the handover, when meeting the handover condition; establishing the connection between the object MME/service gateway and the current LTE-RAN entity serving for UE to be handed over; carrying out the procedure of handover from the source MME/service gateway to the object MME/service gateway; establishing the connection of UE to be handed over, the LTE-RAN entity, the object MME/service gateway and PDN GW orderly; releasing the connection between the source MME/service gateway and the source service LTE-RAN entity for the UE before the handover. By adopting the invention, when some or other MME/service gateway has some status such as overload or link-fault etc, the managed UE handover for service MME/service gateway can be executed, then the load balance among the MME/service gateways can be achieved and the communication is ensured not interruption.

Description

Mobile management entity/service gateway migration method, device and system

The present invention relates to an evolved network, and more particularly to a migration method and related entity device of a Mobility Management Entity (MME)/Service System Architecture Evolution Gateway (hereinafter referred to as "Service Gateway") in an evolved network. system. Background technique

The Universal Mobile Telecommunications System (UMTS) is a third-generation mobile communication system using WCDMA air interface technology. The UMTS system is also commonly referred to as a WCDMA communication system. The UMTS system adopts a structure similar to that of the second generation mobile communication system, including a Radio Access Network (RAN) and a Core Network (CN). The wireless access network is used to handle all wireless related functions, and the CN handles functions such as user location management and service management in the UMTS system, and implements switching and routing functions with the external network. The CN is logically divided into a Circuit Switched Domain (CS) and a Packet Switched Domain (PS). The UTRAN, CN and User Equipment (UE) form the entire UMTS system. The system structure is shown in Figure 1.

UTRAN is the terrestrial radio access network, which contains one or several Radio Network Subsystems (RNS). An RNS consists of a Radio Network Controller (RNC) and one or more base stations (NodeBs). The interface between the RNC and the CN is the Iu interface, and the NodeB and the RNC are connected through the Iub interface. Within the UTRAN, the RNCs are interconnected via a lur interface, which can be connected via a direct physical connection between R Cs or through a transport network. R C is used to allocate and control the radio resources of the NodeB connected or associated with it. The NodeB completes the conversion of the data stream between the Iub interface and the Uu interface, and also participates in some radio resource management. The structure of UTRAN is shown in Figure 2.

The core network structure of the 3G PS domain is shown in Figure 3. It mainly includes the network element: the service GPRS support node. (Serving GPRS Support Node, SGSN) and Gateway GPRS Support Node (GGSN).

Among them, SGSN is a basic component network element of PS network. Its main function is to forward the input/output IP packets for the UEs in the SGSN service area, and its status is similar to the VMSC in the CS domain (visiting the mobile switching center). In addition, the SGSN also integrates a function similar to the Visitor Location Register (VLR) in the CS network. When the user is in the Attached state, the SGSN stores user information and location information related to the group. Similar to the VLR, most of the user information in the SGSN is obtained from the Home Location Register (HLR) during the location update process.

GGS is also a network element function introduced to provide PS service functions in a UMTS network, providing routing and encapsulation of data packets between the PS network and the external data network.

Currently, in 3GPP, various vendors actively research Long Term Evolution (LTE). The purpose of LTE is to provide a network that can reduce latency, improve user data rate, improve system capacity, and low-cost coverage. Only PS domain is used. The service and bearer networks are all IP bearers.

A typical two-layer node evolution network architecture is shown in Figure 4, where:

The MME is connected to the SGSN and the Home Subscriber Server (HSS), and is connected to the evolved UTRAN (EUTRAN) through the S1-MME interface, and is connected to the Serving SAE Gateway through the S11 interface; S10 interface performs signaling transmission;

The HSS is an evolved HLR, which is associated with the MME, stores and updates the registration information of the user; the service gateway connects to the EUTRAN through the S1-U interface;

The packet data network system architecture evolution gateway (PDN SAE Gateway, hereinafter referred to as "PDN gateway") has an interface with the packet data network, and its function is similar to that of the GGSN in the prior art;

The serving gateway and the PDN gateway can be one physical node. If it is a physical node, the signaling between them is an internal message.

In an evolved network, the MME/Serving Gateway and LTE-RAN Entity have a many-to-many relationship, namely Sl-flex. The SI is an interface between the evolved network RAN and the Evolved Packet Core. As shown in Figure 5. An eNodeB (abbreviated as NB) may belong to multiple MME Pool Areas or QoS Pool Areas; an MME/Service Gateway Pool Area is defined as an area in which the UE does not need to change the serving MME/Serving Gateway, one The MME/Serving Gateway Pool Area consists of several parallel MME/Serving Gateways. When an eNodeB belongs to multiple pool areas, it is called overlapping of the pool. For example, eNodeB 1 belongs to Pool Area 1, and eNodeB2\3V belongs to the Heavy Parts of Pool Areas 1 and 2.

In an evolved network, the MME and the serving gateway are not necessarily located on the same physical node, nor are they defined as core network (CN) nodes. For example: It is possible that the serving gateway is in the eNodeB and the MME is in the CN as the control plane node.

In the existing standard, the MME/Serving Gateway handover between the MME/Serving Gateways in the evolved network and the UE in the active mode (in the case where the MME/Serving Gateway is separated, handover between the serving gateways and the MME may occur) ) is divided into two situations:

Case 1: The UE moves out of the MME/Serving Gateway that it currently serves at a certain distance, and the current communication is a non-delay sensitive service.

In the above case, when the UE crosses the MME/Serving Gateway pool area boundary, the handover between the MME/Serving Gateway is performed, and a new ME/Service Gateway is selected for service in the pool area of the new MME/Serving Gateway. Just like the MME/Serving Gateway reselection when the UE is in idle mode. The MME/month service gateway handover diagram is shown in FIG. 6. The user terminal UE1 moves from the MME/month service gateway pool area 1 to the MME/service gateway pool area 2, and the pre-mobile service MME/service gateway is the pool area. The MME/Serving Gateway 1 in 1 and the MME/Serving Gateway in the mobile pool 2 are the MME/Montage Gateway 3 in the pool area 2.

Case 2: The UE is performing delay sensitive services.

In the case of case 2 above, when the UE crosses the border of one MME/Serving Gateway pool area, the original MME/Serving Gateway does not change (because of the concept of Sl-flex, that is, multiple pairs of LTE-RAN Entity and MME/Serving Gateway) Multi-connected), switching is performed between LTE-RAN Entity. Only when the UE enters the LTE-IDLE state, the UE selects an MME/Serving Gateway re-registration in the new MME/Serving Gateway pool area. Because for delay-sensitive services (such as VoIP services), This kind of processing is more suitable, and it is not possible for the user to feel the signal instability because the MME/Serving Gateway is reselected. The MME/Serving Gateway handover diagram is shown in Figure ,. The user terminal UE1 moves from the MME/Serving Gateway pool area 1 to the MME/Serving Gateway pool area 2. The pre-mobile serving MME/Serving Gateway is the MME in the pool area 1. /Serving gateway 1; After the user moves to the MME/Serving Gateway pool area 2, its serving MME/Serving Gateway does not change, it is still MME/Serving Gateway 1; only after the user is in idle mode, it is in the MME/Serving Gateway pool area 2 selects MME/Serving Gateway 3 as its serving MME/Serving Gateway.

In the above case 2, the MME/Serving Gateway can be replaced only when the UE enters the idle mode (LTE_IDLE) state, but in some cases, such as operation and maintenance (O&M) reasons, the MME/Serving Gateway load is too heavy, or The link between the MME/Serving Gateway and the LTE-RAN Entity is too far or the UE is moving too far or other reasons. If the MME/Serving Gateway is not replaced, the communication may be interrupted, and the impact is far greater than because the MME/Serving Gateway is reselected. The resulting signal quality changes briefly.

As shown in FIG. 7 , when the ΜΜΕ/ϋ艮 gateway 1 in the MME/serving gateway pool area 1 is overloaded, in the pool area 1, when the new UE requests access again, the MME may not access the MME. In the service gateway 1, the MME/Serving Gateway 2 in the ool area 1 is selected for access according to the load sharing principle. However, if the load of the current MME/Serving Gateway 1 is compared to '·!, (in fact, there are many UEs below, but many UEs are not registered or in the idle state), there are many UEs activated by the ME/Serving Gateway 2 (Active). Therefore, the load is large; in this way, the UE that newly initiates the access request selects the MME/Serving Gateway 1 to register, and the number of users under the MME/Serving Gateway 1 is more, when many users under the MME/Serving Gateway 1 are converted to In the active state, each user selects the MME/Serving Gateway 1 as the serving ME/Serving Gateway, and the load on the MME/Serving Gateway 1 is large, causing congestion. If the user is using the delay-sensitive service, according to the above situation 2, the MME/service gateway switching is not performed in the current session during the session. When congestion occurs, communication interruption is inevitable. Therefore, there is a need for a congestion control mechanism to achieve load balancing between MME/Serving Gateways. Summary of the invention

An embodiment of the present invention provides an MME/Serving Gateway migration method, which is implemented according to an MME/ The current state of the service gateway is load balanced.

A mobility management entity MME/service gateway migration method, applied to an evolved network, includes: determining whether a current state of a source MME/service gateway serving the user equipment UE before the migration meets a preset migration condition; when the migration condition is met, Select a migrated target MME/service gateway;

Establishing, by the target MME/serving gateway, a serving Long Term Evolution Radio Access Network (LTE-RAN) entity of the migrated UE;

Performing a migration process of the source MME/serving gateway to the target MME/serving gateway; the target MME/serving gateway updating a connection with the PDN gateway; establishing a migrated UE, the LTE-RAN entity, the target The sequential connection of the MME/Serving Gateway and the PDN Gateway.

An MME/service gateway includes: a first migration determination module, a first target selection module, and a first migration execution module;

The first migration determining module is configured to determine whether the current state of the user meets the preset migration condition, and when it is determined that the preset migration condition is met, sending a message to the first target selection module;

a first target selection module, configured to select another MME/service gateway in the network, as a target MME/service gateway after the migrated UE is migrated, and send a migration notification to the target MME/service gateway to cancel the first migration execution module, for receiving A migration notification message sent by another MME/Serving Gateway in the network establishes a connection with the currently serving LTE-RAN entity of the migrated UE to implement UE migration.

An LTE-RAN entity, comprising: a second migration determination module, a second target selection module, and a second migration execution module;

The second migration judging module is configured to determine whether the current state of the service MME/service gateway of the UE meets the preset migration condition, and when it is determined that the preset migration condition is met, sending a message to the second target selection module;

a second target selection module, configured to select another MME/service gateway in the network, as a target MME/service gateway after the migrated UE is migrated, and establish a connection with the target MME/service gateway; Serving MME/Serving Gateway to Target MME/ The migration process of the service gateway.

An MME/service gateway migration implementation system includes: a source MME/serving gateway, a target MME/serving gateway, an LTE-RAN entity, and a PDN gateway;

The source MME/serving gateway determines that the current state of the network meets the preset migration condition, or selects another MME in the network when the LTE-RAN entity determines that the current state of the serving MME/serving gateway of the UE meets the preset migration condition. The serving gateway is the target MME/service gateway after being migrated by the migrated UE;

The target MME/serving gateway establishes a connection with the current serving LTE-RAN entity of the UE, and performs a migration process of the migrated UE from the source MME/serving gateway currently serving to the target MME/serving gateway;

The target MME/service gateway updates the connection with the PDN gateway; establishes a sequential connection of the migrated UE, the LTE-RAN entity, the target MME/service gateway, and the PDN gateway.

With the embodiment of the present invention, when a handover or some abnormal situation due to UE mobility occurs, such as an O&M cause, a certain MME/service gateway load is heavy, or a link failure occurs, the UE may be served. The migration of the MME/service gateway implements load balancing of each MME/service gateway to ensure uninterrupted communication. DRAWINGS

1 is a schematic structural diagram of a prior art UMTS system;

2 is a schematic structural diagram of a prior art UTRAN network;

3 is a schematic structural diagram of a PS domain network in the prior art;

4 is a schematic structural diagram of an evolved network provided in the prior art;

FIG. 5 is a schematic diagram of a prior art evolved network shared Sl-flex configuration;

6 is a schematic diagram of an MME/Serving Gateway handover procedure of a UE under non-delay sensitive service in the prior art;

7 is a schematic diagram of an MME/service gateway handover process of a UE in a delay sensitive service in the prior art; FIG. 8 is a flowchart of a migration process of an MME/service gateway according to an embodiment of the present invention; FIG.

FIG. 9 is a second flowchart of an MME/service gateway migration process according to an embodiment of the present invention;

10 is a third flowchart of an MME/service gateway migration process according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of a migration process in which an MME/Serving Gateway migrates and the serving LTE-RAN Entity does not change according to an embodiment of the present invention;

FIG. 12 is a schematic diagram of a migration process of an MME/Serving Gateway migration and a service LTE-RAN Entity change according to an embodiment of the present invention; FIG.

13 is a schematic diagram of a migration process of an MME/service gateway in a pool area of the same MME/serving gateway according to an embodiment of the present invention;

14 is a second schematic diagram of a migration process of an MME/service gateway in a pool area of the same MME/service gateway according to an embodiment of the present invention;

15 is a schematic diagram of a service ACGW migration process according to an embodiment of the present invention;

FIG. 16 is a flowchart of the MME performing migration when the session management is in the serving gateway, and the serving gateway is not changed according to the embodiment of the present invention;

FIG. 17 is a flowchart of a change of an MME and a service gateway when session management is in a serving gateway according to an embodiment of the present invention;

FIG. 18 is a flowchart of a process for the session management to be migrated by the MME, the MME, and the serving gateway according to an embodiment of the present disclosure;

FIG. 19 is a second flowchart of a procedure for the session management to be migrated by the MME, the MME, and the serving gateway according to an embodiment of the present invention;

FIG. 20 is a schematic structural diagram of an MME/service gateway according to an embodiment of the present disclosure;

FIG. 21 is a schematic structural diagram of an LTE-RAN entity according to an embodiment of the present disclosure;

FIG. 22 is a schematic structural diagram of a system for implementing MME/service network delivery and migration according to an embodiment of the present invention. detailed description

An embodiment of the present invention provides an MME/service gateway migration method, including: determining whether a current state of a source MME/service gateway serving the user equipment UE before the migration meets a preset migration condition; When the migration condition is met, determine a migrated PJ target MME/Serving Gateway; migrate the UE's serving MME/Serving Gateway to the target MME/Serving Gateway (in the following description, establish or release the MME/Serving Gateway and LTE-RAN) The connection between Entity and other network entities is for a single UE).

The method of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 8, which is a flowchart of a method for migrating a MME/service gateway according to the present invention, the following specific steps are included:

Step 1: When the source service MME/serving gateway of the UE is overloaded (such as exceeding a set load threshold, etc.) or link congestion or fault, or the target LTE-RAN entity and the source MME are found during the handover process. When the serving gateway does not have an interface and needs to replace the serving MME/serving gateway, it searches for a target MME/^ service gateway according to information such as load balancing and/or location of the UE;

Step 2: The source MME/serving gateway sends a migration request notification to the target MME/serving gateway, which includes some necessary context information, such as the identifier of the UE, a mobility management context (MM context) such as the location of the UE, and a data packet protocol. Context (PDP context) information such as quality of service (Qos) for UE communication, anchor address (Anchor) address for UE communication, etc.

Step 3: After receiving the migration request notification, the target MME/service gateway allocates the necessary resources, and communicates with the LTE-RAN Entity currently served by the UE (if the LTE-RAN entity handover is involved, may be the target LTE-RAN Entity after the handover), Establishing a connection between the target MME/service gateway and the serving LTE-RAN Entity (the connection between the user plane and the signaling plane);

Step 4: Perform the migration process from the source MME/service gateway to the target MME/service gateway, and perform non-destructive or seamless migration; the specific migration process is not detailed here;

Step 5: Establish a sequence connection of the UE to the monthly LTE-RAN Entity to the target MME/service gateway;

Step 6. The target MME/Serving Gateway updates the connection to the Packet Data Network GateWay (PDN GW) (if there are multiple PDN GWs, it needs to send an update request to each PDN GW);

Step 7. Establish a UE, serve LTE-RAN Entity, target MME/Serving Gateway, and PDN Sequential connection between GWs;

Step 8. Release the connection between the source MME/serving gateway and the source service LTE-RAN Entity of the pre-migration UE.

In the above process, the order of steps 5 and 6 can be changed.

In the process of Figure 8, the MME/Serving Gateway migration process is initiated by the source MME/Serving Gateway, notifying the target MME/Serving Gateway, and the target MME/Serving Gateway initiates resource allocation and connection establishment to the serving LTE-RAN Entity.

In the specific implementation method, the source gateway may initiate the migration, notify the service LTE-RAN Entity, and carry the selected target MME/service gateway address information in the notification (or do not send the target MME/service gateway address information, by LTE). The RAN Enetiy itself selects the target MME/Serving Gateway to send to the serving LTE-RAN Entity, which is connected by the serving LTE-RAN Entity to the selected target MME/month service gateway. The specific implementation steps are shown in Figure 9, including:

Step 1. The source MME/serving gateway decides to initiate the MME/Serving Gateway migration according to its own link or load, and selects a target MME/Serving Gateway as the new serving MME of the UE through signaling interaction or configuration. Service gateway

Step 2: The source MME/serving gateway sends a migration notification to the UE's service LTE-RAN Entity, and carries the selected target ME/service gateway address information and the like to the service LTE-RAN Entity;

Step 3: The service LTE-RAN Entity establishes a connection (control plane and user plane) with the target MME/service gateway, and allocates resources;

Step 4: The migration from the source MME/service gateway to the target MME/service gateway can be performed in a non-destructive or seamless manner; the specific migration process is not detailed here;

Step 5: Establish a connection between the UE and the serving LTE-RAN Entity to the target MME/Serving Gateway. Step 6. The target MME/Serving Gateway updates the connection to the PDN GW. If there are multiple PDN GWs, an update request needs to be sent to each PDN GW. );

Step 7. Establish a sequential connection between the UE, the serving LTE-RAN Entity, the target MME/service gateway, and the PDN GW. Step 8. Release the connection of the source MME/Serving Gateway to the source service LTE-RAN Entity of the pre-migration UE.

In the specific implementation method, the LTE-RAN Entity may also be used to initiate the migration (for example, the LTE-RAN Entity service actively learns the load status or the link status of the source MME/serving gateway, or the source MME/service gateway changes its current load status or chain. The LTE-RAN Entity is notified to the serving LTE-RAN Entity, or the target LTE-RAN Entity discovers that there is no interface with the source MME/Serving Gateway. The serving LTE-RAN Entity decides to initiate the MME/Serving Gateway migration. The specific implementation steps are shown in Figure 10, including:

Step 1. Serving the LTE-RAN Entity to select a suitable target MME/service gateway after initiating the MME/Serving Gateway migration according to the source MME/Serving Gateway load condition or link condition or because there is no interface with the source MME/Serving Gateway. The specific selection strategy can be set, such as selecting the MME/service gateway with the least load, etc.);

Step 7: Corresponding to steps 3-8 in the flow of Figure 9, respectively, not detailed.

According to the MME/Serving Gateway migration method provided by the present invention, the migrated UE may select a UE with a long communication link with the source MME/serving gateway; or a UE with a lower level; or a UE requesting a non-delay sensitive service; Or a UE with a large amount of traffic; or a UE that is undergoing handover, and the like.

In addition, the present invention can also perform access control on the UE that newly initiates the access request. After the MME/service gateway receives the newly initiated connection establishment request from the hosted UE, it determines whether the current state of the UE meets the preset migration. Condition; if the migration condition is met, then a target ME/service gateway is selected, and the UE that newly initiates the connection request is directly registered to the selected target MME/service gateway.

The following examples illustrate various MME/service gateway migration scenarios.

Example 1:

Referring to FIG. 11, a schematic diagram of a migration process in which the MME/Serving Gateway is located in the same physical entity, and the MME/Serving Gateway migrates but the LTE-RAN Entity is not changed.

In Figure 11, the user equipment UE1 moves from the MME/Serving Gateway pool area 1 to the MME/Serving Gateway pool area 2, and when the UE moves to the LTE-RAN Entity 5 of the pool area 2, its serving MME/Serving Gateway is still before the mobile MME/Serving Gateway 1; if at this time due to O&M or MME/ The serving gateway 1 is heavily loaded or the link of the MME/Serving Gateway 1 to the LTE-RANEntity 5 is congested or other reasons (determined by the Radio Resource Management (RRM) policy). According to the above method of the present invention, the serving MME of the UE1/ The serving gateway migrates from the MME/Serving Gateway 1 to the MME/Serving Gateway 2 or the MME/Serving Gateway 3 or the MME/Serving Gateway 4; which one is selected as the target MME/Serving Gateway after migration, which may be based on the location and load of the UE, etc. to make sure. For example, if the location of the UE is based, the MME/Serving Gateway 3 or the MME/Serving Gateway 4 may be preferred because both MME/Serving Gateways are located in the pool area where the UE is currently located. If the MME/Serving Gateway with a smaller load can be selected as the target MME/Serving Gateway according to the load selection, the case of selecting the MME/Serving Gateway 2 is not completely excluded. If the load of the MME/Serving Gateways 1, 3, and 4 is heavy, Then, it is possible to comprehensively consider the migration to the MME/Serving Gateway 2. The migration of the serving MME/service gateway to the MME/Serving Gateway 3 is illustrated in Figure 11. The pre-migration and post-migration communication links of the UE are shown by the thick solid lines in Figure 11.

Example 2:

Referring to FIG. 12, a schematic diagram of a migration process in which the MME/Serving Gateway is located in the same physical entity, the MME/Serving Gateway migrates, and the LTE-RAN Entity is simultaneously changed.

In FIG. 12, the UE is still connected to the MME/Serving Gateway 1 after moving to the LTE-RAN Entity 4, but triggers the handover in the range of moving to the LTE-RAN Entity 5, and the UE switches to the LTE-RAN Entity 5, and according to the load. The reason is that the service MME/Serving Gateway migrates due to the lack of an interface between the LTE-RAN Entity 5 and the MME/Serving Gateway 1, and the source MME/Serving Gateway 1 migrates to the MME/Serving Gateways 2, 3, and 4, Figure 12 The case where the serving MME/service gateway migrates to the MME/Serving Gateway 3 is drawn. The pre-migration and post-migration communication links of the UE are shown by thick solid lines in FIG.

Example 3:

In the same pool area, the MME/Serving Gateway is shared by the resource pool. Generally, if the UE moves to other MME/Serving Gateways under the same pool area, the MME/Serving Gateway migration will not be initiated, which saves signaling. , reduce business disruptions. However, in some special cases, the migration of the service MME/service gateway needs to be performed in the same pool area. For example: Special circumstances are:

1. When it is necessary to perform operation and maintenance on the system, for example, the system is being upgraded or being repaired, currently The service MME/Serving Gateway cannot be used for a period of time.

2. The current serving MME/service gateway is overloaded. For example, most users under the jurisdiction of the MME/Serving Gateway change from idle state to active state in a short time, so that the load of the MME gateway exceeds the load it can bear. .

3. The link between the MME/Serving Gateway and the LTE-RAN Entity is congested or disconnected. When a special situation occurs, the target MME/service gateway can be selected in the same pool area to perform service MME/service gateway migration.

Figure 13 shows that in the same MME/Serving Gateway pool area, the current serving LTE-RAN Entity of UE1 does not change, the pre-migration and post-migration services LTE-RAN Entity are both LTE-RAN Entity3, and the serving MME/Serving Gateway is In the case where the MME/Serving Gateway 1 migrates to the MME/Serving Gateway 2, the pre-migration and post-migration communication links of the UE are shown by thick solid lines in FIG.

14 shows that the current serving LTE-RAN Entity of UE1 is changed in the same MME/Serving Gateway pool area, the pre-migration service LTE-RAN Entity is LTE-RAN Entity2, and the migrated service LTE-RAN Entity is LTE-RAN. Entity3, and the serving MME/Serving Gateway is migrated from the MME/Serving Gateway 1 to the MME/Serving Gateway 2, and the UE pre-migration and post-migration communication links are shown by thick solid lines in FIG.

In the above description, the MME service gateway is a logical function entity belonging to the same physical node or a separate node in the evolved network; the PDN GW as a mobility anchor does not change during the session of the UE. If the high-level node of the evolved network has only one gateway node, that is, the GW can serve as both a serving gateway and a PD gateway. As shown in FIG. 4, the Serving GW has the function of the PDN GW, and the S5 interface is an internal interface and a UE. There is only one Serving GW at most, and there can be multiple PDN GWs. The UE can access a GW through LTE-RAN Entity and then access an external Packet Data Network (PDN), such as a Serving GW and a PDN GW. GW and LTE-RAN Entity are in a many-to-many relationship. When the UE moves to other GWs, the UE's Servin'g GW function can be transferred to the new GW, while the original PND GW function remains on the original GW. No change (the PDN GW can't be changed during the UE's session time, the Serving GW can change). When a session occurs APN (Access Point Name, access point name) When there are different GWs, it is possible that one UE has multiple PND GWs.

If there is only one node GW in the upper layer of the evolved network, the specific implementation method of the MME/service gateway migration provided by the present invention is described in the following Embodiment 4.

Example 4:

Figure 15 is a schematic diagram of the service GW migration process. The communication link initiated by the UE is connected to GW1 from LTE-RAN Entity2, which acts as the Serving GW and also acts as the PDN GW, as shown in the bold dotted link in the figure; when the UE moves to the new LTE-RAN Entity3 The Serving GW can be updated or not updated depending on the load and link conditions. When the LTE-RAN Entity is switched, if the Serving GW is not replaced, the UE still accesses GW1, and its link is as shown by the bold dotted link in Figure 15. The migration of Serving GW may also occur under the load or link of GW1. The migrated link is shown in the thick solid link in Figure 15. In this link, WG1 acts as the PDN GW of the UE. And GW2 acts as the Serving GW of the UE.

Figure 15 shows the case of LTE-RAN Entity change. It is also possible that LTE-RAN Entity is unchanged and GW migration occurs. The specific situation is no longer - exemplified.

There is also a more complicated case where the UE has multiple PDN GIs. In this case, the multiple PDN GWs do not change during a session of the UE.

In this embodiment 4, when the upper layer node of the evolved network has only one access gateway GW node, the GW is the same as the serving GW and the PDN GW; the Serving GW in the pre-migration GW is equivalent to the source MME/service gateway; The Serving GW in the latter GW is equivalent to the target MME/Serving Gateway, and the PDN GW does not change before and after the migration.

In the following, the MME/Serving Gateway separation is assumed, that is, the relationship between the MME Pool area and the serving gateway Pool area is uncertain; The MME migration or the MME and the serving gateway are migrated at the same time.

An X2 interface exists between adjacent LTE-RAN Entities in the pool area, and an X2 interface does not exist between adjacent LTE-RAN Entities in the pool area. Due to the existence of Pool Overlapping, There is often an X2 interface between the actual adjacent LTE-RAN Entities. However, there may also be a switch without an X2 interface. Further, according to the definition of the Pool area, the UE moves within the Poo zone, and the serving node (i.e., the serving MME or the serving gateway) may not be changed unless the foregoing description of the present invention occurs. Described below is the normal handover, the migration process of the MME or the serving gateway that occurs in the case of the Pool zone.

Example 5

Referring to Figure 16, when the SM (session management) is in the serving gateway, the serving gateway does not change, and the MME performs a migration process.

In the process shown in FIG. 16, it is possible that the UE moves to a new LTE-RAN Entity, which has no interface with the source MME, or because the source MME is overloaded or the new LTE-RAN Entity is The link between the source MMEs is congested, faulty, etc., and MME migration needs to be initiated. The specific process is as follows:

Step 1. The UE establishes a connection with the source LTE-RAN Entity1, the source MME 1, and the Serving SAE Gateway.

Step 2: The source LTE-RAN Entity1 decides to initiate the handover according to the information of the UE in the active state, and prepares to switch to another target LTE-RAN Entity 2e. Since the migration often occurs between the pools (because the intra-poor moves, the MME may not change), There may or may not be an X2 interface between the two LTTE-RAN Entities. This example uses the X2 interface as an example.

Step 3: The LTE-RAN Entity1 sends a handover request to the target LTE-RAN Entity2, which carries the RAN context of the UE.

Step 4: After the LTE-RAN Entity2 is ready for the resource, the handover command is sent to the source LTE-RAN Entity1, and the source LTE-RAN Entity1 forwards the packet to the UE to notify the UE to switch to the target LTE-RAN Entity2o.

Step 5. The source LTE-RAN Entity1 returns a handover command response to the target LTE-RAN Entity 2. Step 6. Target LTE-RAN Entity2 understands that there is an interface or source service between the source service gateway. The gateway load and the link satisfy the access conditions, and the service gateway does not need to be changed.

Step 7: The target LTE-RAN Entity2 directly sends a user plane update request message (GTP Bearer Update Request) to the source serving gateway, and carries the user plane information of the target LTE-RAN Entity2 (eg, The IP address of the target LTE-RAN Entity 2 and the GTP tunnel TEID are used to update the downlink tunnel information recorded by the serving gateway.

Step 8. In order to prevent data loss, data forwarding may be performed from the source LTE-RAN Entity1 to the target LTE-RAN Entity2. The data forwarding method can be a data forward or a bi-casting method.

Step 9. The service gateway responds to the user plane update request message (GTP Bearer Update Response).

Step 10: After receiving the handover command, the TIE connects to the target LTE-RAN Entity2 (transmits the RRC message/radio bearer setup, and the target LTE-RAN Entity2 detects the UE that has the handover).

Step 11. The target LTE-RAN Entity 2 finds that it has no interface with the source MME1 or decides to select a new target MME2 and select a new target MME2 because the source MME1 is overloaded or the link between itself and the source MME1 is congested. The standard may be based on load and other reasons.

Step 12: After selecting the target MME2, the target LTE-RAN Entity2 sends a handover request message to the MME2, carrying the identifier of the UE, the target LTE-RAN Entity2 address information, and the source MME1 information, and if the service gateway changes, the selected target is carried. Service gateway information.

Step 13: Target] After receiving the handover request, the MME2 knows that it does not have the context of the UE, and requests the context of the source MME1 of the UE.

Step 14. The source MME1 responds to the context of the UE.

Step 15. The MME2 responds to the handover request.

Step 16. Target LTE-RAN Entity2 feeds back to the source LTE-RAN Entity 1 feedback. Step 17: If the source LTE-RAN Entity 1 completes the data forwarding of the UE, the data forwarding is stopped.

Step 18: The source LTE-RAN Entity 1 releases the user plane and the control plane of the UE.

Step 19. The source LTE-RAN Entity 1 returns a handover completion confirmation to the target LTE-RAN Entity 2.

Step 20: Establish a connection between the UE and the target LTE-RAN Entity 2, the target 2, and the serving gateway, and continue the original service. The above embodiment describes a process in which the serving gateway does not change, the MME migrates, and the migration is initiated by the LTE-RAN Entity. The reason for the initiation is that there is no interface between the target LTE-RAN Entity 2 and the source MME 1, or the source MME is overloaded or the target is overloaded. Link congestion, failure, etc. between LTE-RAN Entity2 and source MME1.

There is no fixed sequence between the above steps 4, 5 and steps 7, 9, 9, 8, and 7, and 9, and after step 11, the actual situation is parallel, and the time sequence is uncertain.

Example 6:

Figure 17 depicts the flow of changes to both the MME and the Serving Gateway.

17 is similar to most of the processes in FIG. 16 except that the target LTE-RAN Entity 2 is determined to select a new target serving gateway 2 for service gateway migration due to no interface with the source serving gateway 1 or source service gateway load, link, and the like. .

The differences in the process are as follows:

In step 3 and step 4, since there is no X2 interface between the source LTE-RAN Entity1 and the target LTE-RAN Entity2, the handover request initiated by the source LTE-RAN Entity1 is forwarded by the selected target MME2 to the target LTE-RAN Entity2; An update request message (GTP Bearer Update Request), carrying a UE identifier, user plane information allocated to the UE, and source service gateway related information;

In steps 11, 12, the destination serving gateway 2 requests the source service gateway 1 for the SM (session management) context of the UE;

Steps 13 and 14 are: if the UE has a service through another PDN gateway, the destination service gateway updates the user plane to the PDN gateway; (If there are multiple PDN GWs, a message needs to be sent to each PDN GW).

In step 15, the target serving gateway 2 returns the user plane information allocated to the UE;

In step 16, the target LTE-RAN Entity2 knows the handover information received by the M E2, and directly selects the MME2 as the target MME, and no other MME is selected;

In step 17, the target LTE-RAN Entit 2 notifies the target service gateway selected by the target MME2. 2 information.

In the above process, the selection of the target ΜΜΕ2, the target service gateway 2 is selected according to information such as load, and the target ΜΜΕ2 is capable of managing the target service gateway 2.

The source MME needs to transfer the handover information to the target LTE-RAN Entity2. If the source MME finds no interface with the target LTE-RAN Entity2, the source MME1 may select one. The new MME2 is the target MME2, which is the MME-triggered migration. It is also possible that the MME only performs the context transfer of the UE between the LTE-RAN Entity or the MME or the service gateway. In FIG. 17, since there is no X2 interface between the source LTE-RAN Entity 1 and the target LTE-RAN Entity 2, the handover request of step 3 is sent to the source MME1, and the source MME1 has no interface with the target LTE-RAN Entity 2, and then selects MME2 (MME2 is usually one MME in the pool area managing LTE-RAN Entity2), sends a handover request to MME2, and MME2 forwards it to the target LTE-RAN Entity2; the target LTE-RAN Entity2 has an interface with the source service gateway or For other workloads and link reasons, decide whether to perform the migration of the service gateway. If the service gateway is migrated, the process shown in Figure 17 is performed.

It may also be that the target LTE-RAN Entity still selects the target MME itself, instead of directly selecting the MEo according to receiving a message from a certain MME.

Embodiments 5, 6, and 7 of the above handover are all based on the assumption that the SM is in the serving gateway. If the SM is in the MME, the selection of the serving gateway is performed by the MME, that is, the migration of the serving gateway is triggered by the MME, and the migration of the MME may be performed by Source MME or LTE-RAN Entity to select and trigger.

Example 7

Referring to FIG. 18, a flow chart of steps for SM to be migrated in the MME, the MME, and the serving gateway. The different steps of the above embodiment are as follows:

An X2 interface exists between the adjacent LTE-RAN Entities. When the handover is triggered, in step 6, the target LTE-RAN Entity 2 decides to trigger the MME migration according to the interface with the source MME or other information, selects the new MME2, and notifies the The downlink user plane bearer information (the following tunnel TEID, IP address) assigned to the UE by the MME2 target LTE-RAN Entity2. Different from the previous method, the migration of the serving gateway is triggered by the MME. In step 11, the MME2 knows that there is no interface between the target LTE-RAN Entity 2 and the source serving gateway 1, and then selects a new target serving gateway 2 for the UE. ;

In step 12, the MME2 sends a user plane update message to the target serving gateway 2, carrying the downlink user plane bearer information of the UE;

In step 13, the target serving gateway 2 returns the uplink user plane information allocated for the UE; in step 14, the MME2 sends the serving gateway uplink tunnel information to the LTE-RAN Entity2, such that the transit of the MME2, the LTE-RAN Entity2 and The user plane between the service gateways 2 is established.

Since step 15 requires a long time of air interface synchronization, steps 7 to 14 are performed in parallel with step 15, thereby saving switching delay. After step 7-14, the tunnel establishment of the target LTE-RAN Entity and the target serving gateway is completed. After the UE accesses the target LTE-RAN Entity, step 16 sends a handover complete message from the target LTE-RAN Entity2 to the target serving gateway 2, and performs a data path. Switch (data path switching), after receiving the handover complete message, the target serving gateway 2 updates the S5/S8 user plane bearer to the PDN gateway, so that the data path is transferred to the switched user plane bearer, that is: the PDN gateway to the target service Gateway 2 goes to LTE-RAN Entity2. The handover completion message of the above step 16 may be directly sent to the target service gateway 2, or may be sent to the target service gateway 2 through the MME.

Alternatively, steps 17, 18 may be used to establish a message carried by the S5/S8, and moved up to the middle of steps 12 and 13, and the handover completion message of step 16 is sent to the target serving gateway 2 and then forwarded to the PDN gateway. The handover completion message functions as a data path switch, and the PDN gateway updates the downlink user plane bearer information after receiving the handover complete message. That is, the UE establishes the S1-U and S5/S8 user plane bearers in the process of accessing the LTE-RAN Entity 2 entity, but does not switch the data path. After the UE accesses the target LTE-RAN Entity, step 16 is performed. The handover completion message initiates a path switch, and the PDN gateway transfers the data path to the switched user plane bearer.

Example 8

Referring to FIG. 19, a flow chart of steps in which the SM is in the MME, the MME, and the serving gateway are both migrated. The different steps of the above embodiment are as follows: If there is no X2 interface between the LTE-RAN Entities, the migration of the MME is triggered by the source MME, and the migration of the serving gateway is also triggered by the MME. As shown in FIG. 19, since there is no X2 interface between the source LTE-RAN Entity1 and the target LTE-RAN Entity2, the LTE-RAN Entity1 sends a handover request to the source MME1 (corresponding to step 3), and the source MME1 is associated with the target LTE-RAN Entity2. There is also no interface or other reason, triggering the migration of the MME, selecting the new target MME2 (corresponding to step 4), and forwarding the handover request to the target LTE-RAN Entity2 (corresponding to steps 5 and 6), after the target LTE-RAN Entity2 is ready for resources Transmitting a handover command to the UE through MME2, MME1, and LTE-RAN Entity1 (corresponding to steps 7 and 8);

It should be noted that step 14 often occurs after steps 10~13. Because the synchronization time of the air interface is long, steps 10~13 are performed in parallel with step 14, thereby saving time delay. After the UE accesses the target LTE-RAN Entity, a data path switch is performed.

The MME2 determines whether to trigger the service gateway migration according to whether the LTE-RAN Entity 2 has an interface with the source service gateway or other reasons. Figure 19 is the flow of triggering the migration of the service gateway. The detailed description of the steps is omitted. Similarly, the UE establishes an S1-U or S5/S8 bearer in the process of accessing the LTE-RAN Entity 2 entity, but does not switch the data path. When the UE accesses the target LTE-RAN Entity, the path is switched, so that the data is enabled. The path is transferred to the switched user plane bearer.

The MME/service gateway migration in the foregoing embodiments is different from the migration method in the prior art in that the behavior of the LTE-RAN Entity does not have the X2 interface is consistent with the X2 interface, that is, the embodiment of the present invention has the following features:

In the process of accessing the LTE-RAN Entity 2 entity, the UE first establishes an S1-U or S5/S8 bearer. In the process of establishing a bearer, the MME first obtains the LTE-RAN Entity tunnel information, sends the information to the serving gateway, and then obtains the serving gateway tunnel. Information is sent to LTE-RAN Entity. The handover command can be sent to the UE as soon as possible, so that the RAN side process can be performed in parallel with other processes, saving the handover delay, and also enabling the UE to switch to the target LTE-RAN Entity as soon as possible to prevent dropped calls, and the UE accesses the target LTE-RAN. After the Entity, the path switch is initiated, so that the data path is transferred to the switched bearer.

According to the MME/service gateway migration method provided by the foregoing embodiment of the present invention, a schematic diagram of a MME/service gateway structure is shown in FIG. 20, including: a first migration determination module, and a first target selection module. And the first migration execution module; wherein:

a first target selection module, configured to select another MME/service gateway in the network, and send the migration notification message to the target MME/service gateway as the target MME/service gateway after the migrated UE is migrated;

The first migration execution module is configured to receive a migration notification message sent by another MME/Serving Gateway in the network, and establish a connection with the currently served LTE-RAN entity of the migrated UE to implement UE migration.

A schematic diagram of an LTE-RAN entity structure is shown in FIG. 21, including: a second migration determination module, a second target selection module, and a second migration execution module;

a second target selection module, configured to select another MME/service gateway in the network, as a target MME/service gateway after the migrated UE is migrated, and establish a connection with the target MME/service gateway; The migration process from the serving MME/Serving Gateway to the target MME/Serving Gateway.

An MME/service gateway migration implementation system is shown in Figure 22, and includes: a source MME/serving gateway, a target MME/serving gateway, an LTE-RAN entity, and a PDN GW;

The source MME/serving gateway serving the user equipment UE determines that the current state of the UE meets the preset migration condition, or the LTE-RAN entity determines that the current state of the serving MME/serving gateway of the UE meets the preset migration condition, and selects the network. Other MME/Serving Gateways in the MME/Serving Gateway as the target MME/Serving Gateway after migration of the migrated UE;

The target MME/serving gateway establishes a connection with the UE currently serving the LTE-RAN entity, and performs a migration process of the migrated UE from the source MME/serving gateway currently serving to the target MME/serving gateway;

The target MME/service gateway updates the connection with the PDN GW; establishes the migrated UE, the The LTE-RA entity, the target MME/Serving Gateway, and the PDN GW are sequentially connected.

In summary, when a certain MME/service gateway is heavily loaded or has a link failure, the MME/service gateway can be migrated to the UE under the jurisdiction, and the load balancing of each MME/service gateway in the network is ensured. Communication is not interrupted.

The embodiment of the present invention selects the migrated UE, such as selecting a UE that is performing handover; a UE with a long communication link with the source MME/serving gateway; or a UE with a lower level; or requesting a non-delay sensitive service The UE, etc., under the premise of implementing load balancing and ensuring uninterrupted communication, try to avoid the impact of high-level users and important services due to the migration of the MME/service gateway.

The embodiment of the present invention can also perform access control on the 新 that newly initiates the connection establishment request, thereby further effectively avoiding the overload phenomenon.

According to the foregoing embodiment of the present invention, the MME/service gateway migration in the same pool area can be implemented, and the MME/service gateway migration can also be performed in different pool areas. When the MME/service gateway migration is performed, the UE services the LTE-RAN. Entity can be changed or not, so that load control and load balancing can be flexibly implemented.

It is apparent that those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of the inventions

Claims

Rights request

A mobility management entity MME/service gateway migration method, applied to an evolved network, the feature comprising:

Determining whether the current state of the source MME/serving gateway serving the user equipment UE before the migration meets the preset migration condition; when the migration condition is met, selecting a migrated target MME/service gateway;

The target MME/serving gateway and the serviced long term evolution radio access network of the migrated UE

Establishing a connection by the LTE-RAN entity;

The method according to claim 1, wherein the determining whether the current state of the source MME/service gateway serving the user equipment UE before the migration meets the preset migration condition comprises: The service gateway determines whether its current state meets the preset migration condition; or

It is determined by the serving LTE-RAN entity of the migrated UE whether the current state of the source service MME/service gateway satisfies a preset migration condition.

The method of claim 2, wherein the determining whether the current state of the source MME/serving gateway meets a preset migration condition includes, but is not limited to:

Determining whether the current load of the source MME/serving gateway exceeds a preset threshold; or determining whether the link between the source MME/serving gateway and the current serving LTE-RAN entity of the UE is too long, congested or disconnected;

It is determined whether there is no interface between the source MME/serving gateway and the LTE-RA entity of the current or target service of the UE.

The method according to claim 2, wherein when the source MME/service gateway determines that its current state meets a preset migration condition, selecting a migrated target MME/service And send a migration request notification to the target/service gateway;

After receiving the migration request notification, the target gateway allocates resources and establishes a connection with the serving LTE-RAN entity of the migrated UE.

The method according to claim 2, wherein when the source/service gateway determines that its current state meets a preset migration condition, selecting a migrated target/service gateway, and The serving LTE-RAN entity of the migrating UE sends a migration request notification, where the selected target MME/service gateway address information is carried in the migration request notification;

The service of the migrated UE After receiving the migration request notification, the LTE-RAN entity establishes a connection with the target MME/month service gateway according to the obtained target MME/service gateway address information.

The method according to any one of claims 1-5, wherein the migrated UE includes but is not limited to: a UE having a long communication link with the source MME/serving gateway; or

a lower level UE; or

Requesting a non-delay sensitive business; or

a UE with a large amount of traffic; or

The UE that is switching.

The method according to claim 6, wherein the selecting a migrated target MME/service gateway includes, but is not limited to:

Selecting the shortest MME/Serving Gateway as the target MME/Serving Gateway according to the location of the migrated UE; and/or

Selecting the least loaded MME/service gateway as the target MME/service gateway according to the load size of each MME/Serving Gateway in the network; and/or

An MME/Serving Gateway that is connected to the currently serving LTE-RAN entity or the target serving LTE-RAN entity of the migrated UE.

The method according to any of claims 1-5, wherein, after the MME/serving gateway receives the newly initiated connection establishment request from the governed UE, it determines whether the current state of the UE satisfies the preset migration. Condition; if the migration condition is met, then a target MME/gateway is selected, and the UE that newly initiates the connection request is directly registered to the selected target ME/service gateway.

The method according to any one of claims 1-5, wherein the source MME/service gateway and the target MME/serving gateway belong to the same pool area or belong to different pool areas.

The method according to any one of claims 1-5, wherein the migrated UE migrated serving LTE-RAN entity and the pre-migration serving LTE-RAN entity are the same LTE-RAN entity, Or for different LTE-RAN entities.

The method of any of claims 1-5, wherein the MME/service gateway is a logical functional entity, belonging to the same physical entity in the evolved network, or belonging to different physical entities.

The method according to any one of claims 1-5, wherein when the high-layer node of the evolved network has only the access gateway GW node, the GW is the serving GW and the PDN GW;

The source MME/serving gateway is a pre-migration service GW;

The target MME/service gateway is a migrated service GW;

The PDN GW does not change before and after the migration.

13. The method according to claim 11, wherein when the MME/Serving Gateway is a separate physical entity and the session management function is at the serving gateway, the migration of the MME or the serving gateway is triggered by the LTE-RAN entity.

14. The method according to claim 11, wherein when the MME/serving gateway is a separate physical entity and the session management function is at the serving gateway, and there is no X2 between the source LTE-RAN entity and the target LTE-RAN entity. At the time of the interface, the migration of the MME is triggered by the source MME.

The method according to claim 13 or 14, wherein the target LTE-RAN entity first establishes a user plane to the serving gateway, and then establishes a control plane to the migrated target MME.

16. The method according to claim 11, wherein when the MME/Serving Gateway is a separate physical entity and the session management function is in the MME, the migration of the serving gateway is triggered by the MME.

The method according to claim 11, wherein when the MME/Serving Gateway is a separate physical entity and the session management function is in the MME, the MME migration is triggered by the LTE-RAN entity or the source MME.

The method according to claim 16 or 17, wherein the UE accesses the target In the process of the LTE-RAN entity, the network side establishes an S1-U or S5/S8 user plane bearer; after the UE accesses the target LTE-RAN entity, performs data path switching, so that the data path is transferred to the switched user plane bearer. Come up.

The method according to claim 18, wherein, in establishing the S1-U user plane bearer, the MME first acquires the LTE-RAN entity bearer information and sends the information to the serving gateway, and then obtains the serving gateway bearer information, and sends the information to the LTE- RAN entity.

An MME/service gateway, comprising: a migration determination module, a first target selection module, and a first migration execution module;

The second migration judging module is configured to determine whether the current state of the service MME/serving gateway of the UE meets the preset migration condition, and when it is determined that the preset migration condition is met, sending a message to the second target selection module;

An MME/service gateway migration implementation system, comprising: a source MME/serving gateway, a target MME/serving gateway, an LTE-RAN entity, and a PDN gateway;

The source MME/service gateway determines that its current state meets a preset migration condition, or When the LTE-RAN entity determines that the current state of the serving MME/serving gateway of the UE meets the preset migration condition, the other MME/serving gateway in the network is selected as the target MME/service gateway after the migrated UE is migrated;

The target MME/serving gateway establishes a connection with the current serving LTE-RAN entity of the UE, and performs a migration process of the migrated UE from the source MME/service gateway of the current service to the target MME/service gateway;

The target MME/Serving Gateway updates the connection with the PDN Gateway; establishes a sequential connection of the migrated UE, the LTE-RAN entity, the target MME/Serving Gateway, and the PDN Gateway.