WO2012155677A1 - Method and system for ensuring service continuity when relay node serves user equipment - Google Patents

Abstract

Disclosed is a method for ensuring service continuity when a relay node (RN) serves a user equipment (UE), comprising: upon receiving a message of unloading an RN or a UE sent by a mobile management entity connected to the RN or the UE, a base station, for serving the RN or the UE, initiating update of the mobile management entity of the RN or the UE. Also disclosed is a system for ensuring service continuity when an RN serves a UE. Through the present invention, a UE served by an RN can be prevented from releasing all connections, thereby ensuring service continuity of the UE served by the RN.

Description

 Method and system for guaranteeing service continuity of RN service UE

 The present invention relates to the field of wireless communication technologies, and in particular to a method and system for guaranteeing service continuity of a relay node (RN) serving user equipment (UE). Background technique

 In order to meet the growing demand for large-bandwidth, high-speed mobile access, the 3rd Generation Partnership Projects (3GPP, Third Generation Partnership Projects) introduced the LTE-Advanced (Long-Term Evolution advance) standard. LTE-Advanced retains the core of LTE for Long-Term Evolution (LTE). Based on this, a series of technologies are used to expand the frequency domain and airspace to improve spectrum utilization and increase system capacity. .

Wireless Relay is a key technology in LTE-Advanced, designed to extend cell coverage, reduce dead zones in communications, balance load, transfer hotspot services, and save user equipment (UE, User Equipment) The transmission power. The relay node (RN) provides similar functions and services to the accessing UE, and accesses an eNB serving the eNB in a manner similar to the normal UE through the radio interface. It is a Donor eNB, referred to as DeNB. The DeNB is connected to a mobility management entity (MME, Mobility Management Entity). The functions provided by the MME for the UE include: non-access stratum signaling, encryption, and integrity protection, and manage mobility of 3GPP users in 2G/3G/LTE networks, including user access control, authentication, and data encryption. Processing of control signaling such as service bearer control, paging, and handover control. The plurality of MMEs serve to serve a common geographic area in which the eNB or DeNB is connected in a mesh structure to a plurality of MMEs in the area. The MME set in the public geographic area constitutes an MME pool, which is also referred to as an MME pool area. Corresponding to several tracking areas, when the UE moves within these tracking areas, there is no need to replace the MME. In the relay scenario, the DeNB needs to select an appropriate MME for the RN, and also select a suitable MME for the UE served by the RN. When selecting the MME for the RN and the UE, the DeNB should consider the load balancing of the MME, that is, ensure the load balancing of each MME in the MME pool area. When a certain MME needs to be removed from the MME pool area in the operation and maintenance process, all UEs or RNs served by the MME are to be offloaded and migrated to other MMEs. In this process, for the UE in the connected mode, the MME initiates an S1 release procedure to the corresponding eNB, and the release causes the tracking area update caused by the load balancing. After receiving the message, the eNB initiates an RRC connection release procedure to the UE, requesting release and The RRC connection between the UEs is also caused by the tracking area update caused by load balancing. After receiving the message, the UE releases the connection with the eNB. For the RN in the connected mode, the MME initiates the S1 release procedure for the tracking area update caused by the load balancing to the corresponding DeNB. After receiving the message, the DeNB releases the RRC connection with the RN. In addition, the RN needs to release the RRC connection with the RN. The RRC connection with the served UE is released. For the MME offloading of the normal UE, only the UE itself is affected, and the MME offloading of the RN affects the service continuity of the UE served by the RN, for example, when the UE served by the RN does not belong to the same MME. The MMEs connected to these UEs may not be uninstalled, so there is no need to perform RRC connection and S1 connection release caused by tracking area update caused by load balancing. Summary of the invention

 In view of this, the main purpose of the present invention is to provide a method and system for ensuring service continuity of a RN serving a UE, so as to solve the problem that the MME of the RN is affected by the RN when the RN and the RN do not belong to the same MME. The problem of service continuity of the serving UE.

 To achieve the above objective, the technical solution of the embodiment of the present invention is implemented as follows:

 An embodiment of the present invention provides a method for ensuring service continuity of a relay node serving user equipment, where the method includes:

A base station serving a relay node or user equipment receives the relay node or user equipment After the message sent by the connected mobility management entity to uninstall the relay node or the user equipment, the mobility management entity of the relay node or the user equipment is initiated to update.

 The mobility management entity of the initiating relay node or the user equipment is updated, specifically: initiating a mobility management entity update of the relay node or the user equipment by means of S1 handover in the cell.

 The initiating the mobility management entity update of the relay node or the user equipment in the manner of the S1 handover in the cell, specifically includes:

 After receiving the message of uninstalling the relay node or the user equipment, the base station serving the relay node or the user equipment sends a reason value to the mobility management entity connected to the relay node or the user equipment, and performs an intra-cell S1 handover. Switching demand message;

 After receiving the handover requirement message, the mobility management entity connected to the relay node or the user equipment selects a target mobility management entity as the source mobility management entity for the relay node or the user equipment, and sends a forwarding relocation request message. Giving the target a mobile management entity;

 Receiving, by the target mobility management entity, the forwarding relocation request message, and determining that the relay node or the serving gateway of the user equipment can serve the relay node or the user equipment, to the serving relay node Or the base station of the user equipment sends a handover request message, and carries a control signaling identifier allocated by the target mobility management entity to the relay node or the user equipment;

 The base station serving the relay node or the user equipment receives the handover request message, and according to the reason value, when the intra-s1 S1 handover determination is an intra-cell handover of the relay node or user equipment, The control signaling identifier assigned by the source mobility management entity to the relay node or the user equipment is updated to a control signaling identifier allocated by the target mobility management entity to the relay node or the user equipment, and the handover request acknowledgement is sent. A message is sent to the target mobility management entity.

 After the target mobility management entity receives the handover request acknowledgement message sent by the base station serving the relay node or the user equipment, the method further includes:

Transmitting, by the target mobility management entity, a forwarding relocation response to the source mobility management entity After receiving the forwarding relocation response message, the source mobility management entity sends a handover command message to the base station serving the relay node or the user equipment; the base station serving the relay node or the user equipment sends the handover command message To the relay node or user equipment;

 After receiving the handover command message, the relay node or the user equipment updates its own security context, and sends a handover confirmation message to the base station serving the relay node or the user equipment; the service serves the relay node or After receiving the handover confirmation message, the base station of the user equipment sends a handover notification message to the target mobility management entity;

 After receiving the handover notification message, the target mobility management entity sends a forwarding relocation complete notification message to the source mobility management entity;

 After receiving the forwarding relocation completion notification message, the source mobility management entity returns a forwarding relocation complete confirmation message to the target mobility management entity;

 After receiving the forwarding relocation complete confirmation message, the target mobility management entity sends a modify bearer request message to the relay node or the serving gateway of the user equipment;

 Receiving, by the serving node of the relay node or the user equipment, the modify bearer request message, after performing bearer modification, sending a modify bearer response message to the target mobility management entity; and then serving the relay node or user equipment The base station sends a user equipment context release complete message or the mobility management entity uninstalls the relay node or user equipment acknowledgement message to the source mobility management entity;

 After receiving the user equipment context release complete message or the mobile management entity uninstalling the relay node or the user equipment acknowledgement message, the source mobility management entity releases the context information related to the relay node or the user equipment.

The message for offloading the relay node or the user equipment is carried by the user equipment context release command message, or the mobile management entity is used to uninstall the relay node or the user equipment to indicate the message bearer; the release reason carried by the user equipment context release command message is : Load balancing caused Tracking area updates.

 The embodiment of the present invention further provides a system for ensuring service continuity of a relay node serving user equipment, including: a relay node or user equipment, a base station serving the relay node or user equipment, and the relay a mobility management entity to which a node or user equipment is connected;

 The mobility management entity that is connected to the relay node or the user equipment is configured to send a message to the base station to uninstall the relay node or the user equipment.

 And the base station is configured to initiate, after receiving the message of the offloading the relay node or the user equipment, a mobility management entity update of the relay node or the user equipment.

 The base station is further configured to initiate a mobility management entity update of the relay node or user equipment in a manner of intra-cell S1 handover.

 The system further includes: a target mobility management entity of the relay node or user equipment, and a serving gateway of the relay node or user equipment;

 The base station is further configured to: after receiving the message of uninstalling the relay node or the user equipment, send, to the mobility management entity connected to the relay node or the user equipment, a handover requirement message whose cause value is an intra-S1 handover ;

 The mobile management entity connected to the relay node or the user equipment is used as a source mobility management entity, and is further configured to select the target mobility management entity for the relay node or user equipment according to the handover requirement message, and send and forward the target a relocation request message to the target mobility management entity, where the target mobility management entity is configured to receive the forwarding relocation request message and determine that the serving gateway can serve the relay node or user equipment Transmitting, to the base station, a handover request message, carrying a control signaling identifier allocated by the target mobility management entity to the relay node or user equipment;

The base station is further configured to, when the handover request message is received, and the inter-cell S1 handover determination is an intra-cell handover of the relay node or user equipment according to the reason value, the source mobility management entity Updating the control signaling identifier assigned to the relay node or user equipment to the A control signaling identifier assigned by the target mobility management entity to the relay node or user equipment, and sending a handover request acknowledgement message to the target mobility management entity.

 The target mobility management entity is further configured to: after receiving the handover request acknowledgement message sent by the base station, send a forward relocation response message to the source mobility management entity;

 The source mobility management entity is further configured to: after receiving the forwarding relocation response message, send a handover command message to the base station; the base station sends the handover command message to the relay node or user equipment;

 The relay node or user equipment, after receiving the handover command message, updates its own security context, and sends a handover confirmation message to the base station;

 The base station is further configured to: after receiving the handover confirmation message, send a handover notification message to the target mobility management entity;

 The target mobility management entity is further configured to: after receiving the handover notification message, send a forwarding relocation complete notification message to the source mobility management entity;

 The source mobility management entity is further configured to: after receiving the forwarding relocation completion notification message, return a forwarding relocation complete confirmation message to the target mobility management entity;

 The target mobility management entity is further configured to: after receiving the forwarding relocation complete confirmation message, send a modify bearer request message to the serving gateway;

 The service gateway is further configured to: after receiving the modify bearer request message, send a modify bearer response message to the target mobility management entity after performing bearer modification;

 The base station is further configured to: after the serving gateway sends a modify bearer response message to the target mobility management entity, send a user equipment context release complete message or the mobility management entity uninstalls the relay node or user equipment acknowledgement message to the source Mobile management entity;

The source mobility management entity is further configured to release the context information related to the relay node or the user equipment after receiving the user equipment context release completion message or the mobility management entity uninstalling the relay node or the user equipment confirmation message. The message for offloading the relay node or the user equipment is carried by the user equipment context release command message, or the mobile management entity is used to uninstall the relay node or the user equipment to indicate the message bearer; the release reason carried by the user equipment context release command message is : Tracking area update caused by load balancing.

 The method and system for ensuring the service continuity of the RN to serve the UE in the embodiment of the present invention. After receiving the message of the RN or the UE that is sent by the source MME of the RN or the UE, the base station serving the RN or the UE initiates the MME update of the RN or the UE. Instead of the MME adopted in the prior art, the release procedure is directly initiated to the corresponding base station. After the MME's MME update is completed, the source MME only uninstalls the RN and does not offload the part of the UE. The MME's MME update is completed. After that, the RN can continue to provide services for the part of the UE, so as to prevent all UEs served by the RN from releasing all connections, and ensuring service continuity of the UE served by the RN. DRAWINGS

 1 is a schematic flow chart of a method for ensuring service continuity of an RN serving UE according to an embodiment of the present invention;

 2 is a schematic flow chart of a method for ensuring service continuity of an RN serving UE according to an embodiment of the present invention;

 FIG. 3 is a schematic flowchart of a method for ensuring service continuity of an RN serving UE according to Embodiment 2 of the present invention; FIG.

 4 is a schematic flowchart of a method for uninstalling a UE according to Embodiment 3 of the present invention;

 FIG. 5 is a schematic flowchart of a method for uninstalling a UE according to Embodiment 4 of the present invention. detailed description

The method for ensuring the service continuity of the RN serving the UE in the embodiment of the present invention is: when receiving the offload message sent by the MME, the base station initiates the MME update of the RN or the UE, instead of the MME offloading. The flow of the RN or UE. As shown in FIG. 1, the method of the embodiment of the present invention includes:

 Step 101: The MME connected to the RN or the UE sends a message for offloading the RN or the UE to the base station serving the RN or the UE.

 The message that the RN or the UE is offloaded may be carried by the user equipment context release command message, or the MME or the UE is used to indicate the message bearer by the MME; further, the MME offloads the RN or the UE indication message to the MME to rebalance the offload RN or the UE indication message. .

 The reason for the release of the user equipment context release command message is as follows: Tracking area update caused by load balancing.

 Step 102: The base station serving the RN or the UE initiates an MME update of the RN or the UE. Specifically, the base station initiates a mobility management entity update of the RN or the UE in a manner of intra-cell S1 handover.

 The solution of the present invention will now be described by way of specific examples.

 Embodiment 1

 When the system needs to remove an MME from the MME pool area during the operation and maintenance process, all UEs or RNs served by the MME are to be offloaded and migrated to other MMEs.

 In this embodiment, it is assumed that the MME needs to perform re-balancing all offloading, and the MME selects the RN of the monthly service to perform the offloading. Accordingly, the UE that is served by the RN and connected to the MME is also uninstalled, and the RN is also uninstalled. The UEs that are not connected to the MME are not uninstalled. Of course, the MME may also select the serving UE to perform the offloading process, and the specific process is the same as the RN selecting the serving RN to perform the uninstall process.

 For example, the process of ensuring service continuity of the RN service UE is as follows:

Step 201: For the RN in the connected mode, the MME connected to it (the MME needs to be removed from the MME pool area) sends a user equipment context release command message to the corresponding DeNB (ie, the eNB serving the RN), and the release reason is load balancing. The resulting tracking area update. At this time, the MME continues to retain the context of the RN and the corresponding data.

 Step 202: After receiving the user equipment context release command message, the DeNB sends a handover request message to the MME connected to the RN, where the cause value is an intra-cell S1 handover, and the purpose is to initiate an MME update of the RN, and the target base station in the handover requirement message Still the DeNB.

 Step 203: After receiving the handover request message of the S1 handover in the cell, the MME connected to the RN selects a new MME (referred to as a target MME in the present invention) as the source MME of the RN, and sends a forwarding relocation request. The message is sent to the target MME, and the message includes the context of the RN in the source MME (such as the RN security context, the RN network capability, the S-GW address of the RN, and the context of the data bearer).

 Step 204: After receiving the forwarding relocation request message, the target MME of the RN determines whether the serving gateway (S-GW) can still serve the RN. If yes, the target MME sends a handover request message to the DeNB; the handover request message includes the target MME. The control signaling identifier assigned to the RN.

 Step 205: After receiving the handover request message, the DeNB determines that the handover is an intra-cell handover of the RN, and the DeNB updates the control signaling identifier allocated by the source MME of the RN to the control signaling identifier allocated by the target MME. Then, a handover request acknowledgement message is sent to the target MME of the RN.

 Step 206: After receiving the handover request acknowledgement message, the target MME of the RN sends a forward relocation response message to the source MME of the RN.

 Step 207: The source MME sends a handover command message to the DeNB, and the DeNB further forwards the handover command message to the RN.

 Step 208: After receiving the handover command message, the RN updates its own security context, and then sends a handover confirmation message to the DeNB.

 Step 209: After receiving the handover confirmation message, the DeNB sends a handover notification message to the target MME of the RN.

Steps 210 to 211, the target MME of the RN sends a Forward Relocation Complete Notification message to the RN. The source MME; the source MME of the RN correspondingly forwards the relocation complete confirmation message to the target MME of the RN.

 Step 212: The target MME of the RN sends an S-GW that modifies the bearer request message to the RN, including the target MME address, the TEID, and the like.

 Step 213: The S-GW of the RN receives the modify bearer request message, performs corresponding modification of the bearer, and then sends a modify bearer response message to the target MME of the RN.

 Step 214: Since the S-GW of the RN is also located in the DeNB, after the S-GW of the RN sends the modify bearer response message to the target MME of the RN, the DeNB may send a user equipment context release complete message to the source MME of the RN, the source of the RN. After receiving the message, the MME releases the context information related to the RN, and the process of the RN being offloaded from the source MME and migrating to the target MME is completed.

 Embodiment 2

 The process of this embodiment is basically the same as the process of FIG. 2, except that, as shown in FIG. 3, in step 301, the MME connected to the RN sends an MME offload RN indication message to the DeNB of the serving RN (better, The MME re-equalizes the RN indication message). Correspondingly, after receiving the MME re-balancing offload RN indication message, the DeNB sends a handover request message to the MME connected to the RN.

 Finally, in step 314, after the S-GW of the RN sends the modify bearer response message to the target MME of the RN, the DeNB may send an MME offload RN acknowledgement message (preferably, the MME rebalances the offload RN acknowledgement message) to the source of the RN. After receiving the message, the source MME of the MME releases the context information related to the RN.

It can be seen from the above two embodiments that the cause value initiated by the DeNB is the MME update procedure of the RN in the intra-cell S1 handover. For the UE served by the RN and not belonging to the same MME as the RN, the source MME is only The RN is offloaded, and the UE is not offloaded. Therefore, after the RN switches from the source MME to the target MME, the RN can continue to provide services for these UEs, ensuring continuity of UE services. In addition, the embodiment of the present invention further proposes a process flow of uninstalling the UE when the MME is removed. Embodiment 3

 When the system needs to remove an MME from the MME pool area during the operation and maintenance process, all UEs or RNs served by the MME are offloaded and migrated to other MMEs.

 In this embodiment, it is assumed that the MME needs to perform partial offloading, and then the normal user equipment node, that is, the UE, is preferentially uninstalled; of course, the RN may also be selected for offloading.

 For example, as shown in FIG. 4, the process of ensuring service continuity of the RN serving UE includes:

 Step 401: For the UE in the connected mode, the MME connected to the MME (the MME needs to be removed from the MME pool area) sends a user equipment context release command message to the corresponding eNB (ie, the eNB serving the UE), and the release reason is load balancing. The resulting tracking area update. At this time, the MME continues to retain the context of the UE (here, the UE served by the source MME) and the corresponding data bearer information.

 Step 402: After receiving the user equipment context release command message, the eNB sends a handover request message to the MME connected to the UE, where the cause value is an intra-cell S1 handover, and the target base station in the handover requirement message is still the eNB.

 Step 403: After receiving the handover request message of the S1 handover in the cell, the MME connected to the UE selects the target MME for the UE as the source MME of the UE, and sends a Forward Relocation Request message to the target MME, where the message includes the UE. The context of the source MME (such as UE security context, UE network capability, S-GW address of the UE, and the context of the data bearer).

 Step 404: After receiving the forwarding relocation request message, the target MME of the UE determines whether the serving gateway (S-GW) of the UE can still serve the UE. If yes, the target MME sends a handover request message to the eNB; the handover request message includes The control signaling identifier assigned by the target MME to the UE.

Step 405: After receiving the handover request message, the eNB determines that the handover is an intra-cell handover of the UE. Then, the eNB updates the MME corresponding to the UE to the control signaling identifier allocated by the target MME to the UE, and then sends a handover request acknowledgement message to the target MME of the UE.

 Step 406: After receiving the handover request acknowledgement message, the target MME of the UE sends a forward relocation response message to the source MME of the UE.

 Step 407: The source MME sends a handover command message to the eNB, and the eNB further forwards the handover command message to the UE.

 Step 408: After receiving the handover command message, the UE updates the information of the security context, and then sends a handover confirmation message to the eNB.

 Step 409: After receiving the handover confirmation message, the eNB sends a handover notification message to the target MME of the UE.

 Steps 410 to 411, the target MME of the UE sends a Forward Relocation Complete Notification message to the source MME of the UE, and the source MME of the UE forwards a Relocation Complete Confirmation Acknowledgement message to the target MME of the UE.

 Step 412: The target MME of the UE sends a modify bearer request message to the S-GW of the UE, where the target MME address, the TEID, and the like are included.

 Step 413: The S-GW of the UE sends a modify bearer response message to the target MME of the UE. Step 414: Since the S-GW of the UE is also located in the eNB, after the S-GW of the UE sends the modify bearer response message to the target MME of the UE, the eNB may send a user equipment context release complete message to the source MME of the UE, the source of the UE. After receiving the message, the MME releases the context information related to the UE, and the process of the UE unloading from the source MME and migrating to the target MME is completed.

 Embodiment 4

 When the system needs to remove an MME from the MME pool area during the operation and maintenance process, all UEs or RNs served by the MME are offloaded and migrated to other MMEs.

The process of this embodiment is basically the same as the process of FIG. 4, except that, as shown in FIG. 5, in step 501, the MME connected to the UE sends the MME to the eNB serving the UE. The UE indication message (preferably, the MME rebalancing offloading the UE indication message); correspondingly, after receiving the MME re-balancing offloading UE indication message, the eNB sends a handover requirement message to the MME connected to the UE.

 Finally, in step 514, after the S-GW of the UE sends the modify bearer response message to the target MME of the UE, the eNB may send an MME offload UE acknowledgement message (preferably, the MME rebalances the UE acknowledgement message) to the source of the UE. The MME, after receiving the message, the source MME of the UE releases the context information related to the UE.

 In order to implement the foregoing method, the embodiment of the present invention further provides a system for ensuring service continuity of an RN serving UE, including: an RN or a UE, a base station serving the RN or the UE, and an MME connected to the RN or the UE;

 The MME connected to the RN or the UE is configured to send a message for offloading the RN or the UE to the base station;

 The base station is configured to initiate an MME update of the RN or the UE after receiving the message of uninstalling the RN or the UE.

 The base station is further configured to initiate an MME update of the RN or the UE in an intra-cell S1 handover manner.

 The system further includes: a target MME of the RN or the UE and a serving gateway of the RN or the UE; the base station is further configured to: after receiving the message of the offloading the RN or the UE, send the cause value to the MME connected to the RN or the UE as the intra-s1 S1 Switching demand message for switching;

 The MME connected to the RN or the UE is used as the source MME, and is further configured to select a target MME for the RN or the UE according to the handover requirement message, and send a forwarding relocation request message to the target MME. The target MME is configured to receive the forwarding relocation request. And sending a handover request message to the base station, and carrying the control signaling identifier allocated by the target MME for the RN or the UE, when the service and the service gateway can serve the RN or the UE;

The base station is further configured to: when receiving the handover request message, and according to the cause value, the S1 handover criterion in the cell When the intra-cell handover is performed by the RN or the UE, the control signaling identifier allocated by the source MME for the RN or the UE is updated to the control signaling identifier allocated by the target MME to the RN or the UE, and the handover request acknowledgement message is sent to the target MME. .

 The target MME is further configured to: after receiving the handover request acknowledgement message sent by the base station, send a forward relocation response message to the source MME;

 The source MME is further configured to: after receiving the forwarding relocation response message, send a handover command message to the base station; the base station sends a handover command message to the RN or the UE;

 The RN or the UE, after receiving the handover command message, updates its own security context, and sends a handover confirmation message to the base station;

 The base station is further configured to: after receiving the handover confirmation message, send a handover notification message to the target MME; the target MME is further configured to: after receiving the handover notification message, send a forwarding relocation complete notification message to the source MME;

 The source MME is further configured to: after receiving the forwarding relocation complete notification message, return a forwarding relocation complete confirmation message to the target MME;

 The target MME is further configured to: after receiving the forwarding relocation complete confirmation message, send a modify bearer request message to the serving gateway;

 The service gateway is further configured to receive the modify bearer request message, and after the bearer modification, send the tamper-response response message to the target MME;

 The base station is further configured to: after the serving gateway sends the modify bearer response message to the target MME, send a user equipment context release complete message or the MME uninstalls the RN or the UE acknowledge message to the source MME;

 The source MME is further configured to release the context information related to the RN or the UE after receiving the user equipment context release complete message or the MME uninstalling the RN or the UE acknowledgement message.

The message of the RN or the UE is offloaded by the user equipment context release command message, or the MME or the UE indicates that the message is carried by the MME; The release reason carried by the user equipment context release command message is: Tracking area update caused by load balancing.

 The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim  A method for ensuring service continuity of a relay node serving user equipment, the method comprising:  The base station serving the relay node or the user equipment initiates the relay node or the user equipment after receiving the message sent by the mobility management entity connected to the relay node or the user equipment to uninstall the relay node or the user equipment. Mobile management entity update.  The method for ensuring the service continuity of the relay node serving the user equipment according to claim 1, wherein the initiating relay node or the mobility management entity of the user equipment is updated, specifically: starting in a manner of S1 handover in the cell. The relay node or the mobility management entity of the user equipment updates.  The method for ensuring the service continuity of the relay node serving the user equipment according to claim 2, wherein the initiating the mobility management entity update of the relay node or the user equipment in the manner of intra-cell S1 handover, specifically :  After receiving the message of uninstalling the relay node or the user equipment, the base station serving the relay node or the user equipment sends a reason value to the mobility management entity connected to the relay node or the user equipment, and performs an intra-cell S1 handover. Switching demand message; After receiving the handover requirement message, the mobility management entity connected to the relay node or the user equipment selects a target mobility management entity as the source mobility management entity for the relay node or the user equipment, and sends a forwarding relocation request message. And to the target mobility management entity; when the target mobility management entity receives the forwarding relocation request message, and determines that the relay node or the serving gateway of the user equipment can serve the relay node or the user equipment, Transmitting, by the base station serving the relay node or the user equipment, a handover request message, carrying a control signaling identifier allocated by the target mobility management entity to the relay node or the user equipment; Receiving, by the base station of the user equipment, the handover request message, and determining, according to the reason value, that the intra-cell S1 handover is a cell of the relay node or user equipment When the internal handover is performed, the control signaling identifier assigned by the source mobility management entity to the relay node or user equipment is updated to a control signaling identifier allocated by the target mobility management entity to the relay node or user equipment. And send a handover request acknowledgement message to the target mobility management entity.  The method for ensuring service continuity of a relay node serving user equipment according to claim 3, wherein the target mobility management entity receives the handover request sent by the base station serving the relay node or the user equipment After confirming the message, the method further includes:  Sending, by the target mobility management entity, a forward relocation response message to the source mobility management entity;  After receiving the forwarding relocation response message, the source mobility management entity sends a handover command message to the base station serving the relay node or the user equipment; the base station serving the relay node or the user equipment sends the handover command message To the relay node or user equipment;  After receiving the handover command message, the relay node or the user equipment updates its own security context, and sends a handover confirmation message to the base station serving the relay node or the user equipment;  After receiving the handover confirmation message, the base station serving the relay node or the user equipment sends a handover notification message to the target mobility management entity;  After receiving the handover notification message, the target mobility management entity sends a forwarding relocation completion notification message to the source mobility management entity;  After receiving the forwarding relocation completion notification message, the source mobility management entity returns a forwarding relocation complete confirmation message to the target mobility management entity;  After receiving the forwarding relocation complete confirmation message, the target mobility management entity sends a modify bearer request message to the relay node or the serving gateway of the user equipment; Receiving, by the serving node of the relay node or the user equipment, the modify bearer request message, after performing bearer modification, sending a modify bearer response message to the target mobility management entity; Then, the base station serving the relay node or the user equipment sends a user equipment context release complete message or the mobility management entity uninstalls the relay node or the user equipment acknowledgement message to the source mobility management entity;  After the source mobility management entity receives the user equipment context release complete message or the mobility management entity uninstalls the relay node or the user equipment acknowledgement message, the context information related to the relay node or the user equipment is released.  The method for guaranteeing the service continuity of the relay node serving the user equipment according to any one of claims 1 to 4, wherein the message for offloading the relay node or the user equipment is carried by the user equipment context release command message, or Unloading the relay node or the user equipment indication message bearer by the mobility management entity;  The reason for the release of the user equipment context release command message is: tracking area update caused by load balancing.  A system for ensuring service continuity of a relay node serving a user equipment, comprising: a relay node or a user equipment, a base station serving the relay node or user equipment, and a connection with the relay node or user equipment Mobile management entity;  The mobile management entity connected to the relay node or the user equipment is configured to send, to the base station, a message for uninstalling the relay node or the user equipment;  The base station is configured to initiate a mobility management entity update of the relay node or user equipment after receiving the message of uninstalling the relay node or the user equipment.  The system for ensuring service continuity of a relay node serving user equipment according to claim 6, wherein the base station is further configured to initiate mobility management of the relay node or user equipment in a manner of intra-cell S1 handover. Entity update. 8. The system for guaranteeing service continuity of a relay node serving user equipment according to claim 7, wherein the system further comprises: a target mobility management entity of the relay node or user equipment, and the relay node or user Service gateway of the device; The base station is further configured to: after receiving the message of uninstalling the relay node or the user equipment, send a cause value to the mobility management entity connected to the relay node or the user equipment. S1 handover switching demand message;  The mobile management entity connected to the relay node or the user equipment is used as a source mobility management entity, and is further configured to select the target mobility management entity for the relay node or user equipment according to the handover requirement message, and send and forward the target Relocating a request message to the target mobility management entity;  The target mobility management entity, configured to send a handover request message to the base station when receiving the forwarding relocation request message, and determining that the serving gateway can serve the relay node or user equipment, a control signaling identifier allocated by the target mobility management entity to the relay node or user equipment;  The base station is further configured to, when the handover request message is received, and the inter-cell S1 handover determination is an intra-cell handover of the relay node or user equipment according to the reason value, the source mobility management entity Updating a control signaling identifier assigned to the relay node or user equipment to a control signaling identifier assigned by the target mobility management entity to the relay node or user equipment, and transmitting a handover request acknowledgement message to the Target mobility management entity.  9. The system according to claim 8, wherein the relay node serves the service continuity of the user equipment, wherein  The target mobility management entity is further configured to: after receiving the handover request acknowledgement message sent by the base station, send a forwarding relocation response message to the source mobility management entity; the source mobility management entity is further configured to: After receiving the forwarding relocation response message, sending a handover command message to the base station; the base station sending the handover command message to the relay node or user equipment; The relay node or user equipment, after receiving the handover command message, updates its own security context, and sends a handover confirmation message to the base station; The base station is further configured to: after receiving the handover confirmation message, send a handover notification message to the target mobility management entity;  The target mobility management entity is further configured to: after receiving the handover notification message, send a forwarding relocation complete notification message to the source mobility management entity;  The source mobility management entity is further configured to: after receiving the forwarding relocation completion notification message, return a forwarding relocation complete confirmation message to the target mobility management entity;  The target mobility management entity is further configured to: after receiving the forwarding relocation completion confirmation message, send a modify bearer request message to the serving gateway;  The service gateway is further configured to: after receiving the modify bearer request message, perform a bearer modification, and send a modify bearer response message to the target mobility management entity;  The base station is further configured to: after the serving gateway sends a modify bearer response message to the target mobility management entity, send a user equipment context release complete message or the mobility management entity uninstalls the relay node or user equipment acknowledgement message to the source Mobile management entity;  The source mobility management entity is further configured to release the context information related to the relay node or the user equipment after receiving the user equipment context release completion message or the mobility management entity uninstalling the relay node or the user equipment confirmation message.  The system for guaranteeing the service continuity of the relay node serving the user equipment according to any one of claims 6 to 9, wherein the message for offloading the relay node or the user equipment is carried by the user equipment context release command message, or Unloading the relay node or the user equipment indication message bearer by the mobility management entity;  The reason for the release of the user equipment context release command message is: tracking area update caused by load balancing.