CN102958033A

CN102958033A - Method for changing core network nodes for mobile relay users

Info

Publication number: CN102958033A
Application number: CN2011102486434A
Authority: CN
Inventors: 李婷; 陈喆; 潘瑜; 张欢; 张莉莉
Original assignee: Potevio Institute of Technology Co Ltd
Current assignee: Potevio Institute of Technology Co Ltd
Priority date: 2011-08-26
Filing date: 2011-08-26
Publication date: 2013-03-06

Abstract

The invention provides a method for changing core network nodes for mobile relay users. The method includes: an MRN (mobile relay node) detects change in current location and transmits change information to a current MME (mobility management entity) of UE (user equipment); the MME of the UE needing to be changed is determined according to the location information received by the current MME and other preset information of the UE, and change to the MME of the UE is triggered; a new MME group is selected for the UE through the MRN or the current MME, a new MME is selected from the new MME group on the basis of load balance; the new MME acquires UE context from the current MME, and UE P-GW (packet data network gateway) and UE S-GW (serving gateway) are determined for the UE. Core network nodes can be changed for the UE under the MRN by the method while a base station is unchanged by the UE, and transmission source load of UE data is effectively decreased.

Description

Method for changing core network node of mobile relay user

Technical Field

The present invention relates to a technique in a mobile relay system, and particularly to a method for changing a core network node of a mobile relay user.

Background

When a user rides on a high-speed rail, the LTE UE accesses the LTE network through the MRN deployed on the high-speed rail and accesses an external network through the UE P-GW in the LTE network. Fig. 1 shows a self-backhauling network architecture to support UE access to an external network under MRN. The MRN is accessed to an MRN return transmission network (including the DeNB and an MME/S-GW/P-GW serving the MRN) through the DeNB, and is connected to an MME/S-GW of the UE under the MRN through the MRN return transmission network, and the UE is accessed to an external network through the UE P-GW. The two thick curves in the figure represent S1-C between MRN and UE MME and S1-U between MRN and UE S-GW, respectively.

FIG. 2 is a diagram illustrating a change in RN S-GW/RN MME serving an MRN during the MRN operation. As shown in FIG. 2, the MRN is served by E-UTRAN nodes (DeNB) and Core Network (CN) nodes (including RN MME, RN S-GW and RN P-GW) in the MRN backhaul transport network. The MRN changes the accessed DeNB (MRN is switched between DeNB) in the moving process; when moving to another geographical area, the MRN may change the MME and S-GW serving the MRN in the course of changing the accessed DeNB. And the RN P-GW in the MRN return transmission network is connected with the UE core network and is used as a routing node for the communication between the UE core network and the MRN. For the UE under MRN, the UE under MRN is always connected to the MRN cell during the operation process, and the base station is not changed, so that the CN node (UE MME/UE S-GW/UE P-GW) serving the UE cannot be changed. Thus, core network data (control plane and user plane) of the registered UE are transmitted via the S5/S8 interface between the original RN P-GW and the new RN S-GW.

In the moving process of the MRN, the RN S-GW serving the MRN is continuously changed, and the distance between the MRN and the original RN P-GW is continuously increased. Considering that mobile data services already occupy a large share of mobile services and the user data demand is rapidly increasing, and the UE will often interact with massive data when accessing the Internet, the data needs to be transmitted through the S5/S8 interface between the original RN P-GW and the new RN S-GW, which increases the demand for the S5/S8 interface transmission resources, thereby increasing the deployment cost of the S5/S8 interface transmission resources. In order to reduce the burden of transmission resources of the S5/S8 interface and save deployment cost, a part of UE data needs to be shunted, specifically, the core network node of the registered UE is changed to a core network node closer to the new RN S-GW, and the new UE core network node interacts data with the UE through the RN P-GW closer to the RN S-GW and the new RN S-GW, that is, the UE data transmitted through the longer S5/S8 interface between the original RN P-GW and the new RN S-GW is shunted through the shorter S5/S8 interface between the new RN P-GW and the new RN S-GW.

Considering that the base station of a registered UE is always unchanged (always MRN), the prior art of changing the core network node of the UE is as follows: the registered UE changes the core network node without changing the base station; and balancing MME load.

For network operation and maintenance, when an MME needs to be removed from an MME Pool for maintenance reasons, or when a new MME is to be added to an MME Pool, the OAM may instruct the MME to offload all or part of the UEs it serves. MME offloading UE, specifically:

for the UE in ECM-IDLE state with active TAU initiation (such as termination of periodic TA update timer) or ATTACH, the MME completes the corresponding procedure and instructs the base station to release the corresponding S1 connection;

for the UE in the inactive ECM-CONNECTED state (e.g., the MME receives an S1 connection release request sent by the base station indicating that the UE is inactive), the MME instructs the base station to release the corresponding S1 connection;

the MME should offload the above UEs preferentially, if all UEs need to be offloaded, the MME may instruct the base station to release the corresponding S1 connection if it neither initiates TAU or ATTACH proactively nor is released S1 connection due to inactivity for the remaining UEs.

The "MME instructs the base station to RELEASE the corresponding S1 connection," specifically, means that the MME includes "load balancing requested" cause in the UE CONTEXT RELEASE COMMAND message sent to the base station. The base station sends RRC connection RELEASE message (the message includes "load balancing TAU required" cause) to the UE after receiving the UE CONTEXT RELEASE COMMAND message. And after receiving the RRC connection release message, the UE performs cell reselection, accesses the selected cell and initiates a TAU process. The UE does not include S-TMSI in the RRC connection request message sent to the base station, and does not include GUMMEI in the RRC connection establishment completion message sent to the base station, so that the base station can judge the reason why the UE initiates the TAU process, and then selects a new MME for the UE based on load balancing.

In the above process, the triggering condition for the MME to offload the UE does not consider to reduce the burden of the UE data transmission resources, and the UE cannot be offloaded in a targeted manner according to the condition of the UE, so that the transmission pressure of the transmission resources of the S5/S8 interface cannot be effectively relieved.

In addition, when the UE moves within a large range along with the base station, the new MME is different from the MMEPool to which the original MME belongs, and how to determine the new MME Pool for the UE is not considered at present.

Disclosure of Invention

The invention provides a method for changing a core network node of a mobile relay user, which can change the core network node for UE under MRN under the condition that the UE does not change a base station, so as to effectively reduce the transmission resource burden of UE data.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for changing a core network node of a mobile relay user comprises the following steps:

when the MRN detects that the position of the MRN or the UE accessing the MRN is changed, the MRN reports the current position information of the MRN or the UE accessing the MRN to the current MME of the UE accessing the MRN;

after the current MME receives the current position information, under the condition that the preset information of the UE accessed to the MRN and maintained by the current MME changes, the current MME determines the MME of the UE needing to be changed and triggers the MRN to change the MME of the UE;

the MRN determines a new MME group for the UE and selects a new MME from the group based on load balancing;

and the new MME acquires the context of the UE from the current MME and determines UEP-GW and UE S-GW for the UE.

Preferably, the preset information of the UE accessing the MRN maintained by the current MME is: the UE type, the traffic condition of the UE in the preset time, the traffic condition of the UE in a non-GBR bearer in the preset time, the ECM state of the UE, the active condition of UE service, and the APN type of an external network accessed by the UE, or any combination thereof.

Preferably, the current location information of the MRN is: eNB ID/DeNBGlobal eNB ID of DeNB accessed by MRN, TAI/ECGI/CSG ID of cell accessed by MRN, MME Group ID or geographic area code of MME serving MRN.

Preferably, the reporting, by the MRN, of the current location information to the current MME is: and the MRN sends an eNB Configuration Update message to the current MME, and the current position information is carried in the message by using the newly added IE.

Preferably, the reporting, by the MRN, of the current location information to the current MME is: the MRN sends a Location Report message to a current MME, if the obtained current position information is TAI or ECGI of a cell accessed by the MRN, the TAI or ECGI is directly carried in the Location Report message, otherwise, the current position information is carried in the Location Report message by using a newly added IE.

Preferably, the triggering MRN to change the MME of the UE is: the current MME sends a UE CONTEXT RELEASE COMMAND message carrying a load balancing TAU required reason to the MRN; after receiving the message, the MRN sends an RRC CONNECTION RELEASE message carrying the reason of load balancing TAU required to the UE.

Preferably, the MRN determines, for the UE, a new MME group as:

configuring a corresponding relation between current position information of self UE or UE accessed to the self UE and an MME group in an MRN in advance, or a corresponding relation between position information change of the self UE or UE accessed to the self UE and the MME group, wherein the MRN selects the MME group corresponding to the current position information or the position information change according to the corresponding relation;

or, the MRN reports the current location information to the MRN OAM, which designates an MME group for the MRN.

Preferably, the new MME obtaining the context of the UE from the current MME is:

the new MME requests the context of the UE from the current MME through paths of RN P-GW and RN S-GW connected with the new MME and the RN P-GW connected with the current MME; the current MME returns the context of the UE to the new MME through a reverse path;

or,

and the new MME acquires the context of the UE from the current MME through transmission resources between UE core networks.

after the current MME receives the current position information, under the condition that the preset information of the UE accessed to the MRN maintained by the current MME changes, the current MME determines the MME of the UE needing to be changed, determines a new MME group for the UE, and selects a new MME from the MME group based on load balance;

Preferably, the current MME determines, for the UE, a new MME group as: configuring a corresponding relation between MRN or MRN-accessed UE current position information and an MME group in advance in an MME, or a corresponding relation between MRN or MRN-accessed UE position information change and an MME group, wherein the MME selects the MME group corresponding to the current position information or the position information change according to the corresponding relation;

or, the current MME reports the current position information to MME OAM, and MME OAM assigns an MME group for the current MME.

the current MME sends the context of the UE to the new MME through paths of RN P-GW, RN S-GW connected with the current MME and RN P-GW connected with the new MME;

or,

and the current MME sends the context of the UE to the new MME through the transmission resources between the UE core networks.

According to the technical scheme, after the MRN detects that the current position changes, the MRN sends the change information to the current MME of the UE; and the current MME determines the MME of the UE to be changed according to the received position information and other preset information of the UE, and triggers the MME of the UE to be changed. Next, a new MME group is selected for the UE by the MRN or the current MME, and a new MME is selected in the new MME group based on load balancing. The new MME obtains the context of the UE from the current MME and determines the UE P-GW and the UE S-GW for the UE. By the method, the core network node can be changed for the UE under the MRN under the condition that the UE does not change the base station, so that the transmission resource burden of UE data is effectively reduced.

Drawings

Fig. 1 is a schematic diagram of a self-backhauling network architecture;

FIG. 2 is a schematic diagram of a change in RN S-GW/RN MME serving an MRN during MRN operation;

fig. 3 is a flowchart illustrating a method for changing a node of a core network of a mobile relay user according to an embodiment of the present invention;

fig. 4 is a specific flowchart of a method for changing a node of a core network of a mobile relay user according to a second embodiment of the present invention.

Detailed Description

For the purpose of making the objects, technical means and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.

The basic idea of the invention is: and the UE MME triggers the change of the UE MME according to the UE condition, and the MRN selects a new UE MME for the UE.

The invention provides two methods for changing a core network node of a mobile relay user, and the concrete implementation of the two methods is described through a concrete embodiment.

The first embodiment is as follows:

in this embodiment, when a core network node is changed, a new UE MME is selected through the MRN to which the UE accesses.

Fig. 3 is a specific flowchart of a method for changing a node of a core network of a mobile relay user in this embodiment. As shown in fig. 3, the method includes:

step 301, when the MRN detects that the location of the MRN itself or the UE accessing the MRN itself changes, the MRN reports the current location information of the MRN itself or the UE accessing the MRN itself to the current MME of the UE accessing the MRN itself.

Here, the UE and the MRN accessed by the UE are generally at the same position, and thus, the position information of the UE and the MRN accessed by the UE is the same. Specifically, the location information may be: eNB ID/DeNB Global eNB ID of the DeNB accessed by the MRN; TAI/ECGI/CSGID of the MRN accessed cell; MME Group ID of MME serving MRN (MRN can get this information from GUMMEI in NAS); the MRN may obtain the location information from a specific device (e.g., GPS receiver) when the location information is an administrative zone (which may be divided by the operator or may be used).

When the MRN reports location information to the current MME (hereinafter referred to as MME a) of the UE, an eNB Configuration Update message (MRN- > UE MME) may be used, and a new IE representing location information is added to the message; alternatively, a Location Report message (MRN- > UE MME) may be used, and since the existing Location Report message may carry an ECGI or TAI, if the Location information is an ECGI or TAI, the ECGI or TAI may be directly carried in the Location Report message, and if the Location information is other Location information than the ECGI and TAI, a new IE indicating the Location information needs to be added to the Location Report message.

Step 302, after receiving the current location information, MME a determines whether a UE core network node needs to be changed, if so, step 303 is executed, otherwise, the process is ended.

After the MME a receives the location information sent by the MRN, it is determined that the location information has changed, at this time, it is necessary to further determine whether other preset information of the corresponding UE changes, if so, it is determined that the UE core network node needs to be changed, otherwise, it is determined that the UE core network node does not need to be changed.

Specifically, the other preset information of the corresponding UE may be: UE type (e.g., whether multiple PDN connection is supported, whether SIPTO is supported, if SIPTO is supported, whether the visited APN allows a change to P-GW); the UE P-GW reports the traffic condition in the UE preset time (for example, divided into three levels of high, medium and low, the UE P-GW counts the traffic level of the UE and reports the traffic level to the UE MME) or the traffic condition in the non-GBR load only to the UE MME (or through OAM of each other); ECM status of the UE (ECM-IDLE, ECM-CONNECTED); the active status of the UE service (for the UE in the ECM-CONNECTED state), such as the frequency of establishing, modifying, and releasing the EPS bearer in the UE control plane; the type of APN of the external network (e.g. Internet) the UE accesses. The specific preset information may be one or any combination of the above information.

Step 303, the MME a triggers the MRN to change the MME of the UE.

The method for triggering the UE core network node change by the MME a may specifically be: MME A sends UE CONTEXT RELEASE COMMAND message to MRN, and the message carries cause 'load balancing TAU required'; correspondingly, after receiving the message, the MRN sends an rrcconnectionrelease message to the UE, and the message carries cause "load balancing requested". After receiving the request, the UE can enter an RRC idle state by using the existing mechanism, reselect an MRN cell and re-access the network through the MRN. Thus, the operation mechanism of the UE is not changed. Of course, one reason may be redefined as needed to trigger a change in the MME, but modifications to existing protocols are required.

Step 304, the MRN determines an MME group for the UE and selects a new UE MME for the UE based on load balancing in the determined MME group.

In this step, the specific way for the MRN to determine the new MME group for the UE may be:

configuring a corresponding relation between the current position information of the UE or the UE accessed to the UE and an MME group in an MRN in advance, or a corresponding relation between the position information change of the UE or the UE accessed to the UE and the MME group, and selecting the MME group corresponding to the current position information or the position information change by the MRN according to the configured corresponding relation; wherein, the corresponding relation can be configured through MRN OAM;

or, the MRN reports the current position information to the MRN OAM, and the MRN OAM designates an MME group for the MRN; specifically, when selecting an MME group, the MRN or MRN-accessed UE current location information may be stored in the MRN OAM in advance as a correspondence relationship with the MME group, or a correspondence relationship between a change in location information of the MRN or MRN-accessed UE and the MME group may be stored in the MRN OAM in advance, and the MRN OAM may select an MME group corresponding to the change in current location information or location information according to the configured correspondence relationship and notify the MRN of the selected MME group.

After selecting the MME group, a new UE MME is selected for the UE in the MME group based on load balancing. The detailed selection can be realized by those skilled in the art, and the detailed description is omitted here.

Step 305, the new UE MME obtains the context of the UE from MME a and determines the appropriate UE P-GW and UE S-GW for the UE.

In this step, the method for acquiring the context of the UE from the MME a by the new UE MME may be:

the new UE MME requests the context of the UE from the original UE MME through the paths (namely the realization path in the figure 2) of the new RN P-GW, the new RN S-GW and the original RN P-GW, and the original UE MME returns the context of the UE to the new UE MME through a reverse path, namely the new RN P-GW, the new RN S-GW and the original RN P-GW are used as routing forwarding nodes for S10 interface IP packet transmission between the new UE MME and the original UE MME; the physical paths among the new RN P-GW, the new RN S-GW and the original RN P-GW already exist, and the transmission of the UE context can be realized by using the physical paths.

Or can also be:

the new UE MME obtains the context of the UE from the old UE MME via transmission resources between the UE core networks (e.g. via forwarding by the operator backbone node).

The method for determining the UE P-GW and the UE S-GW may adopt an existing manner, specifically:

the new UE MME may select a closer S-GW for the UE based on the UE current location information. Specifically, the new UE MME may report the current location information of the UE to its OAM, and the MME OAM returns an S-GW identifier to the MME;

the new UE MME still keeps the original P-GW of the UE unchanged, and a GTP tunnel is established between the new UE S-GW and the original UE P-GW;

for SIPTO UE, aiming at APN corresponding to PDN connection established for UE by original UE P-GW, new UE MME determines whether to provide SIPTO function related to the APN for the UE, if so, a) the new UE MME deactivates the established PDN connection (indicating "reactivation requested"), and when the UE requests PDN connection type procedure according to the indication of the original UE P-GW, the new UE MME selects new UE P-GW which is closer to the new UE S-GW for the UE; b) if all PDN connections established by the UE in the original UE P-GW need to relocate GW, the UE MME can initialize an 'explicit detach with reassertach required' procedure;

when UE supporting multiple PDN connection requests PDN connection capability procedure, if the corresponding APN which does not establish related PDN connection, the new UE MME selects a new UE P-GW which is closer to a new UE S-GW for the UE, and a GTP tunnel is established between the new UE S-GW and the new UE P-GW for the UE.

By this time, the MME, P-GW and S-GW of the UE are re-determined, namely the change process of the UE core network node is completed.

Example two:

in this embodiment, when a core network node change is performed, a new UE MME is selected through a current MME of the UE.

Fig. 4 is a specific flowchart of a method for changing a node of a core network of a mobile relay user in this embodiment. As shown in fig. 4, the method includes:

step 401, when the MRN detects that the location of the MRN itself or the UE accessing the MRN itself changes, the MRN reports the current location information of the MRN itself or the UE accessing the MRN itself to the current MME of the UE accessing the MRN itself.

Step 402, after receiving the current location information, MME a determines whether a UE core network node needs to be changed, if so, step 403 is executed, otherwise, the process is ended.

The processing of steps 401 to 402 is the same as the processing of steps 301 to 302 in the first embodiment, and will not be described again here.

In step 403, the current MME of the UE determines a new MME group for the UE, and selects a new UE MME for the UE based on load balancing in the determined MME group.

In this step, the specific way for the current MME to determine the new MME group for the UE may be:

and the current MME determines a new MME group based on the MRN or the current position information of the UE accessed to the MRN.

The specific way for the current MME to determine the new MME group for the UE may be:

configuring a corresponding relation between the current position information of MRN or the UE accessed to the MRN and an MME group in advance in the current MME, or a corresponding relation between the position information change of the MRN or the UE accessed to the MRN and the MME group, and selecting the MME group corresponding to the current position information or the position information change by the MME according to the configured corresponding relation; wherein, the corresponding relation can be configured through MME OAM;

or the current MME reports the MRN or the current position information of the UE accessed to the MRN to the MMEOAM, and MME OAM designates an MME group for the MME; specifically, when selecting an MME group, the MME OAM may store a correspondence between current location information of MRN or MRN-accessed UE and the MME group in MME OAM, or a correspondence between a change in location information of MRN or MRN-accessed UE and the MME group in MME OAM, and the MME OAM may select an MME group corresponding to the current location information or the change in location information according to the configured correspondence, and notify the selected MME group to the MME.

Step 404, the new UE MME obtains the context of the UE from MME a and configures a new GUTI for the UE to serve the UE.

The specific way for the new UE MME to obtain the context of the UE from the MME a may be: the MMEA sends the context of the UE to the new MME. The MME a may send the request through a path of the original RNP-GW, the new RN S-GW, and the new RN P-GW, or may send the request through a transmission resource (for example, forwarding through a backbone node of an operator) between the UE core networks.

The process of configuring the new GUTI for the UE (e.g., via the GUTI new traffic command message) is the same as the conventional process, and will not be described herein again.

In step 405, the new UE MME determines the appropriate UE P-GW and UE S-GW for the UE.

The processing in this step is the same as the processing in step 305, and is not described here again.

So far, the flow of the core network node changing method in this embodiment is ended.

As can be seen from the specific implementation of the present invention, the two methods provided in the first and second embodiments can change the core network node for the UE under the MRN without changing the base station, so as to effectively reduce the transmission resource burden of the UE data.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A method for changing a mobile relay user core network node, the method comprising:

2. The method of claim 1, wherein the preset information of the UE accessing the MRN maintained by the current MME is: the UE type, the traffic condition of the UE in the preset time, the traffic condition of the UE in a non-GBR bearer in the preset time, the ECM state of the UE, the active condition of UE service, and the APN type of an external network accessed by the UE, or any combination thereof.

3. The method of claim 1, wherein the current location information of the MRN is: eNB ID/DeNB Global eNB ID of a DeNB accessed by the MRN, TAI/ECGI/CSG ID of a cell accessed by the MRN, MME Group ID or geographic area code of an MME serving the MRN.

4. The method of claim 1, wherein the MRN reporting the current location information to the current MME is: and the MRN sends an eNB configuration update message to the current MME, and the current position information is carried in the message by using the newly added IE.

5. The method of claim 3, wherein the MRN reporting the current location information to the current MME is: the MRN sends a Location Report message to a current MME, if the obtained current position information is TAI or ECGI of a cell accessed by the MRN, the TAI or ECGI is directly carried in the Location Report message, otherwise, the current position information is carried in the Location Report message by using a newly added IE.

6. The method of claim 1, wherein the triggering the MRN to change the MME of the UE is: the current MME sends a UE CONTEXT RELEASE COMMAND message carrying a load balancing TAUrequired reason to the MRN; after receiving the message, the MRN sends an RRC CONNECTIONRELEASE message carrying the reason of load balancing TAU required to the UE.

7. The method of claim 1, wherein the MRN determines a new MME group for the UE as:

8. The method of claim 1, wherein the new MME obtaining the context of the UE from the current MME is:

or,

9. A method for changing a mobile relay user core network node, the method comprising:

10. The method according to claim 9, wherein the preset information of the UE accessing the MRN maintained by the current MME is: the UE type, the traffic condition of the UE in the preset time, the traffic condition of the UE in a non-GBR bearer in the preset time, the ECM state of the UE, the active condition of UE service, and the APN type of an external network accessed by the UE, or any combination thereof.

11. The method of claim 9, wherein the current location information of the MRN is: eNB ID/DeNB Global eNB ID of a DeNB accessed by the MRN, TAI/ECGI/CSG ID of a cell accessed by the MRN, MME Group ID or geographic area code of an MME serving the MRN.

12. The method of claim 9, wherein the MRN reporting the current location information to the current MME is: and the MRN sends an eNB configuration update message to the current MME, and the current position information is carried in the message by using the newly added IE.

13. The method of claim 11, wherein the MRN reporting the current location information to the current MME is: the MRN sends a Location Report message to a current MME, if the obtained current position information is TAI or ECGI of a cell accessed by the MRN, the TAI or ECGI is directly carried in the Location Report message, otherwise, the current position information is carried in the Location Report message by using a newly added IE.

14. The method of claim 9, wherein the current MME determines a new MME group for the UE as: configuring a corresponding relation between MRN or MRN-accessed UE current position information and an MME group in advance in an MME, or a corresponding relation between MRN or MRN-accessed UE position information change and an MME group, wherein the MME selects the MME group corresponding to the current position information or the position information change according to the corresponding relation;

15. The method of claim 9, wherein the new MME obtaining the UE context from the current MME is:

or,