WO2010003452A1

WO2010003452A1 - Method and device for changing at least one first network element in a pool of first network elements and communication system comprising such device

Info

Publication number: WO2010003452A1
Application number: PCT/EP2008/058799
Authority: WO
Inventors: Andreas Platzer; Olaf Pollakowski
Original assignee: Nokia Siemens Networks Oy
Priority date: 2008-07-07
Filing date: 2008-07-07
Publication date: 2010-01-14

Abstract

A method and a device are provided for changing at least one first network element in a pool of first network elements, wherein said pool of first network elements is associated with at least one second network element, the method comprising the steps of (i) the at least one second network element is identified; and (ii) an interface between the at least one first network element and the at least one second network element is configured or set up. Furthermore, a communication system is suggested comprising said device.

Description

Method and device for changing at least one first network element in a pool of first network elements and communication system comprising such device

The invention relates to a method and to a device for changing at least one first network element in a pool of first network elements and to a communication system comprising such device.

In many countries mobile network services are broadly available, in some markets these services are even reaching a stage of saturation. Therefore, Mobile Network Operators (MNOs) are not only focusing on increasing the number of subscribers and increasing their average revenue per user (ARPU) , they are also trying to improve their cost position by reducing operational expenditures (OPEX) . In industrial countries the costs for operating the network is exceeded by the costs for the operating personnel. Thus, there is an increasing need for reducing the human workload in an already deployed network and enabling the MNOs to shift the human workload to more profitable issues like, e.g., service management and marketing of the services.

For a new network technology to be deployed or provided such requirement may be met by avoiding a certain degree of complexity in a design of the system's architecture and of its components (cf., e.g., a simplified EPS (E-UTRAN/EPC) network architecture and simplified system functions) . Also, features can be provided for network elements and their management system to cope with the system's complexity and to avoid errors of human operators, i.e., assuring that the network is well configured, optimized and substantially fault-free. The investment in such features (results in an increased CAPEX) can thus be traded off against OPEX reduction feasible. Next Generation Mobile Networks (NGMNs) may result in a parallel operation of GSM, UMTS and NGMN with substantially the same number of operating personnel. However, in NGMNs the number of network nodes will significantly increase regarding E-UTRAN in comparison to 2G and 3G systems. Hence, in E- UTRAN/EPC there is a requirement for self-configuring and self-optimizing systems.

A Mobility Management Entity (MME) is a network element that supports a "pooling" concept, wherein an evolved NodeB (eNB) can be connected to or associated with one or more MME (s) (via an Sl-interface) . A Pool of MMEs is provided for several

MMEs having the same MME Group ID (MMEGI) . For the Pool of

MMEs there is a MME Pool Area comprising at least one eNB (in particular a lot of such eNBs) , wherein preferably each eNB of the MME Pool Area is connected to each MME of the Pool of

MMEs.

The MME Pool Area may preferably be understood as an area within which a user equipment (UE) may be served without any need to change the serving MME. The MME Pool Area may be supplied by one or more MMEs (constituting said "Pool of MMEs") in parallel. MME Pool Areas are a collection of complete Tracking Areas. MME Pool Areas may further overlap with one another.

A Globally Unique MME Identifier (GUMMEI) may comprise a Mobile Country Code (MCC) , a Mobile Network Code (MNC) and an MME Identifier (MMEI) . Furthermore, the MMEI may comprise the MME Group ID (MMEGI) and an MME Code (MMEC), i.e. the MME Identifier can be noted as

When an MME is introduced (as first member of a pool) or added to an already existing Pool of MMEs, the Sl-interfaces between this MME and the eNBs of the associated MME Pool Area need to be established. This requires significant configuration effort to provide a consistent configuration to the MME and all eNBs of the MME Pool Area. Considering the huge number of eNBs associated with the MME Pool Area (up to 10.000), this is a huge task to be performed manually by the operator.

In existing systems, OAM interfaces of the MMEs and of the eNBs allow for a configuration of the network nodes. The operator has to manually ensure consistency for any status change or use case. In the example stated above, the operator has to manually update the new MME as well as all eNBs of the associated MME Pool Area. This approach is error-prone, costly and it may require an intricate exchange of information between radio and core management systems, which still is bulky and often "paper"-based.

The problem to be solved is to overcome the disadvantages stated above and in particular to provide an efficient approach of changing or adding a member of a pool of first network elements regarding its relationship to an associated group of second network elements .

This problem is solved according to the features of the independent claims . Further embodiments result from the depending claims.

In order to overcome this problem, a method is provided for changing at least one first network element in a pool of first network elements, wherein said pool of first network elements is associated with at least one second network element, comprising the steps:

- the at least one second network element is identified;

- an interface between the at least one first network element and the at least one second network element is configured or set up. This approach advantageously allows for an automation of adding a new network element, e.g., a new MME to an MME Pool. By changing such MME, updates are due to be processed for numerous network elements. The operator may just introduce the new MME, the updates required are performed by the system via, e.g., means of self-configuration.

If, e.g., Sl-interfaces from eNBs to the changed MME have to be set up, the MME is configured including setting up its MMEGI. The eNBs associated with the particular MME Pool Area are supplied with the information required for establishing a Sl-interface to this changed MME, e.g., its IP address. Then, the eNBs may set up the Sl-interfaces.

It is noted that changing the MME may comprise adding, replacing, moving, deleting, updating, restarting, etc. an MME.

It is noted that the first network elements may be or be associated with MMEs; alternatively, the first network elements may be or be associated with eNBs. Accordingly, the second network elements are of type eNB or of type MME.

In an embodiment, changing the at least one first network element comprises:

- adding said at least one first network element;

- replacing said at least one first network element;

- moving said at least one first network element;

- removing said at least one first network element.

"Changing" the at least one first network element may reflect any sort of physical or logical change, amendment, replacement, update or the like; it may also refer to a change of the network element's identity or identification, e.g. , the GUMMEI. It is also possible that the second network element is changed (e.g., added, replaced, moved, removed, updated or the like) .

For example, regarding a removal of a network element, be it a first or a second network element, the yet established interface may be utilized for conveying a message from the at least one first network element to the at least second network element or vice versa indicating that the sending network element will be removed. Then, the receiving network element may deactivate the interface to this network element (which is (to be) removed) .

Hence, in addition or as an alternative to OAM mechanisms, the established interface can be configured by messages conveyed via said interface.

In another embodiment, the first network element is a mobility management entity (MME) .

In a further embodiment, the second network element is a base station, a radio station or a NodeB, in particular an evolved NodeB (eNB) .

In a next embodiment, the method comprises the step:

- the at least one second network element is identified and is provided with information regarding the at least one first network element.

It is also an embodiment that the method comprises the step:

- the at least one second network element is identified and the at least one first network element is provided with information regarding the at least one second network element.

Pursuant to another embodiment, the interface comprises an Sl-interface between each second network element and between the at least one first network element. According to an embodiment, a configuration function is provided, wherein the at least first network element registers with said configuration function and/or wherein the at least second network element registers with said configuration function.

It is also an embodiment that an OAM system or a central entity is used for updating said configuration function.

In yet another embodiment the said configuration function is updated by at least one notification.

According to a further embodiment, upon a change of the first network elements, the at least one second network elements is informed by the configuration function.

According to another embodiment, upon a change of the first network elements, the at least one second network elements is informed by the configuration function.

In yet another embodiment, upon a change of the second network elements, the at least one first network elements is informed by the configuration function.

According to an embodiment, upon a change of the second network elements, the at least one second network element is informed by the configuration function.

The problem stated above is also solved by a device comprising a and/or being associated with a processor unit and/or a hard-wired circuit and/or a logic device that is arranged such that the method as described herein is executable on said processor unit.

According to an embodiment, the device is a communication device, in particular a or being associated with a network element or an operation and maintenance component. The problem stated supra is further solved by a communication system comprising the device as described herein.

Embodiments of the invention are shown and illustrated in the following figures:

Fig.l shows a diagram comprising MMEs gathered in a Pool of

MMEs and eNBs gathered in a MME Pool Area, wherein each MME has an interface to each eNB;

Fig.2 shows an information flow diagram between an eNB and an MME-PA-SCF;

Fig.3 depicts an information flow diagram comprising an MME and the MME-PA-SCF;

Fig.4 shows the eNB, the MME and the MME-PA-SCF in an information flow diagram.

The approach provided herein may be applicable in particular regarding various use cases, e.g., adding, moving, replacing, removing a network element of a first type from a pool of network elements of said first type. Each such network element of first type is in particular associated with at least one further network element of a second type, e.g., an evolved NodeB (eNB) , establishing a Pool Area for the network elements of the first type (constituting the Pool of network elements of said first type) .

Hereinafter, the network elements of first type are exemplary chosen to be Mobility Management Entities (MMEs) with a particular MME Group ID (MMEGI) thereby constituting a Pool of MMEs 101 according to Fig.l. With regard to the example depicted in Fig.l, several eNBs (eNBl to eNB3) build an MME

Pool Area 102, wherein each such eNBl to eNB3 is connected to each MMEl to MME3 of the Pool 101. If, e.g., a further MMEn is connected to the Pool 101, the eNBs of the MME Pool Area 102 need to get aware of this MMEn and vice versa. According to the approach provided, adding said MMEn is sufficient to automatically establish all interfaces required between the MMEn and all eNBs of the Pool Area 102. The interfaces between the eNBs and the MMEs are preferably Sl-interfaces .

The use case "Addition of a new MME to an MME Pool Area (including the case where the first MME of a MME Pool is introduced" is just an example. The approach provided is applicable to various other use cases as well, e.g., replace, delete, move, update of a network element, e.g. a MME and/or a eNB . It is further noted that more than one MME may be processed accordingly.

The scenario described herein can be applied vice versa in the same manner, i.e. a eNB can be changed and the at least one MME is updated accordingly. There may as well be a Pool of eNBs associated with a eNB Pool Area.

The approach provided allows a consistent provision of identical and/or dependent data sets for different Network Elements (NEs) or it may enable an update of NEs due to changes in another NE. Hence, consistency of data is provided automatically throughout the system at a significant reduction of OPEX. In particular, only one NE may be configured, changed (also replaced or removed) or installed by an operator and affected NEs are automatically identified and updated and/or configured by the system itself.

The approach suggests a logical function called "MME Pool Area Self-Configuration Function" (MME-PA-SCF) . With this function, the operator needs to configure only the MMEGI for the new MME or the operator assigns the new MME to a certain MME Pool. The rest is advantageously processed in an automated fashion by the MME-PA-SCF.

It is noted that such MME-PA-SCF is an exemplary functionality that may be deployed or be associated with at least one network element and/or a central component of the system providing the automated functionality as described herein. It may, e.g., be arranged in a way to actively or passively communicate with network elements and/or it may be arranged to process notifications of an OAM entity.

This MME-PA-SCF may in particular provide the following:

(a) An ability to learn and to store information related to eNBs, MMEs, MME Pools and MME Pool Areas. Examples may comprise learning and storing

- the IP addresses of eNBs and MMEs,

- which MMEs are member of an MME Pool and

- which eNBs belong to an MME Pool Area.

(b) An ability to identify eNBs belonging to an MME Pool Area associated with an MME Pool.

(c) A functionality to provide either the new MME (to be added to the pool) or the identified eNBs with information required to set up interfaces, in particular Sl-interfaces .

Logical MME Pool Area Self-Configuration Function (MME-PA- SCF)

Update of the MME-PA-SCF with MME-related information

When a new MME is added to the network, the MME-PA-SCF may be provided with related information. Preferably, the GUMMEI and the IP address of the new MME are provided. The GUMMEI may be

There are several possibilities to update the MME-PA-SCF with MME-related information, for example: (a) Each MME registers itself at the MME-PA-SCF, providing its assigned GUMMEI and its IP address. The MME may have been configured before registration with classical OAM mechanisms .

(b) The OAM system configuring the MME may also update the MME-PA-SCF with MME related information.

(c) Notifications available in classical OAM systems regarding the newly installed MME are used in order to update the MME-PA-SCF.

The MME-PA-SCF may set up and/or modify a table as follows comprising information from a eNB registration message. Hence, the table comprises for every MME the MME Pool it is associated with as well as its IP address.

MME Table:

When MME-related information stored also in the MME-PA-SCF is changed, the MME-PA-SCF is updated as well.

Update of the MME-PA-SCF with eNB related information

When a new eNB is added to the network, the MME-PA-SCF may be provided with related information, preferably, the MMEGI and the IP address of the new eNB.

As shown in the scenario for the MME above, there are several possibilities to update the MME-PA-SCF with eNB-related information. The examples provided supra may apply here as well . The MME-PA-SCF may set up a table as follows comprising information from the eNB registration message. Hence, the table comprises for every eNB the MME Pool serving this eNB (with the MMEGI) and its IP address.

eNB Table:

eNB 1 eNB-ID 1 MMEGI A IP 1 eNB 2 eNB-ID 2 MMEGI B IP 2 eNB 3 eNB-ID 3 MMEGI B IP 3 eNB 4 eNB-ID 4 MMEGI A IP 4 eNB 5 eNB-ID 5 MMEGI B IP 5

When eNB-related information stored also in the MME-PA-SCF is changed, the MME-PA-SCF is updated as well.

MME Pool Area Self-Configuration (eNB triggered Sl set-up)

With a new MME being announced to the MME-PA-SCF, in particular the following steps may be processed:

The MME-PA-SCF checks the MMEGI presented in the registration message for matches in the eNB-Table. In other words, the eNBs of the MME Pool Area associated to the MME Pool identified via the MMEGI are identified.

(b) The MME-PA-SCF informs the identified eNBs about the presence of a new MME in their MME Pool and about the MME IP address. This may be achieved, e.g., as follows: (bl) The eNBs are informed directly by the MME-PA-SCF. (b2) The MME-PA-SCF configures the information in/for a (already existing) "master" MME of the same pool, said master forwarding the information to the identified eNBs. (b3) The MME-PA-SCF uses OAM mechanisms to update the eNBs . (c) The eNB sets up an Sl-interface to the new MME using the supplied IP address.

Example :

A new MME 5 is announced with the following information at the MME-PA-SCF

This means that the new MME_5 will be a member of the MME Pool identified by MMEGI_B. The eNBs of the associated MME Pool Area are eNB 2, eNB 3 and eNB 5, see table below:

These eNBs (eNB_2, eNB_3 and eNB_5) need to be informed about the presence of the new MME_5 and about its IP address IP_5.

MME Pool Area Self-Configuration (MME triggered Sl set-up)

The MME-PA-SCF checks the MMEGI presented in the registration message for matches in the eNB-Table. In other words, the eNBs of the MME Pool Area associated to the MME Pool identified via the MMEGI are identified

(b) The MME-PA-SCF informs the MME about the identified eNBs and their IP addresses. This may be achieved, e.g., as follows : (bl) The MME is informed directly by the MME-PA-SCF. (b2) The MME-PA-SCF uses OAM mechanisms to update the MME.

(c) The MME sets up the Sl-interface to the identified eNBs .

Architectural Options for the Implementation of the MME-PA- SCF

Possibility A: MME-PA-SCF implemented in the Network Management (NM)

Scenario 1 : Core and Radio Network operated by one MNO

In this scenario it is assumed that there is one NM managing the radio and core network. The MME-PA-SCF can be implemented and/or logically associated with the NM.

Scenario 2: Core and Radio Network operated by different MNOs

In this scenario it is assumed that the DM/EM and NM of different vendors are not connected with each other. Hence, the OAM system of the core operator has no knowledge about the radio network and vice versa. In such case, the MME-PA- SCF is implemented in the NM in particular if information exchange is established or allowed between the OAM systems.

Possibility B: New Node for the MME-PA-SCF

The MME-PA-SCF may be implemented also in a new node connected via direct and/or standardized interfaces to the MMEs and/or to the eNBs.

For example, Fig.2 to Fig.4 show information flow diagrams in case the MME-PA-SCF is implemented in a new node and that the NEs register directly with this node.

Hence, Fig.2 shows an information flow diagram between an eNB and an MME-PA-SCF. The eNB sends a message via, e.g., an application layer protocol, "eNB self announcement" comprising as parameters the eNB-Id, the MMEGI and its own IP address. The MME-PA-SCF sends a eNB self announcement response for, e.g., confirmation purposes. Hence, according to Fig.2, the eNB registers at the MME-PA-SCF.

Fig.3 depicts an MME that sends an MME self announcement message comprising the GUMMEI and its own IP address as parameters to the MME-PA-SCF. The MME-PA-SCF conveys an MME self announcement response thereby confirming registration of the MME with the MME-PA-SCF.

Furthermore, Fig.4 shows the eNB, the MME and the MME-PA-SCF in an information flow diagram. The MME-PA-SCF pushes information of the MMEs' IP addresses to the eNB. The eNB provides a response for confirmation purposes. Next, the eNB sends a eNB Sl-interface setup request to the MME and receives a response for confirmation purposes.

Advantages of the MME Pool Area Self-Configuration Function

Only the new MME needs to be initially set with the GUMMEI (= MCC I I MNC I I MMEGI | | MMEC) . The impacted eNBs are identified automatically by the MME-PA-SCF. The new MME and the identified eNBs are updated automatically with the required information. The Sl-interfaces are set up automatically.

List of Abbreviations :

ARPU average revenue per user

CAPEX Capital Expenditures DM Domain Manager eNB evolved NodeB

EM Element Manager

EPC Evolved Packet Core

EPS Evolved Packet System E-UTRAN Evolved UTRAN

GSM Global System for Mobile communications

GUMMEI Globally Unique MME Identifier

MCC Mobile Country Code

MME PA SCF MME Pool Area Self Configuration Function MME Mobility Management Entity

MMEC MME Code

MMEGI MME Group ID

MMEI MME Identifier

MNC Mobile Network Code MNO Mobile Network Operator

NE Network Element

NGMN Next Generation Mobile Networks

NM Network Management

OAM Operation and Maintenance OPEX Operational Expenditures

SCTP Stream Control Transmission Protocol (RFC

2960)

SON Self Organizing UE User Equipment UMTS Universal Mobile Telecommunications System UTRAN UMTS Terrestrial Radio Access Network

Claims

Claims :

1. A method for changing at least one first network element in a pool of first network elements, wherein said pool of first network elements is associated with at least one second network element, comprising the steps:

- the at least one second network element is identified;

- an interface between the at least one first network element and the at least one second network element is configured or set up.

2. The method according to claim 1, wherein changing the at least one first network element comprises: - adding said at least one first network element;

- replacing said at least one first network element;

- moving said at least one first network element;

- removing said at least one first network element.

3. The method according to any of the preceding claims, wherein the first network element is a mobility management entity.

4. The method according to any of the preceding claims, wherein the second network element is a base station, a radio station or a NodeB, in particular an evolved NodeB.

5. The method according to any of the preceding claims, comprising the step:

6. The method according to any of the preceding claims, comprising the step:

7. The method according to any of the preceding claims, wherein the interface comprises an Sl-interface between each second network element and between the at least one first network element.

8. The method according to any of the preceding claims, wherein a configuration function is provided, wherein the at least first network element registers with said configuration function and/or wherein the at least second network element registers with said configuration function .

9. The method according to claim 8, wherein an OAM system or a central entity configures the at least first network element and registers with and/or updates said configuration function.

10. The method according to claim 8, wherein an OAM system or a central entity is used for updating said configuration function by at least one notification.

11. The method according to any of claims 8 to 10, wherein upon a change of the first network elements, the at least one second network elements is informed by the configuration function.

12. The method according to any of claims 8 to 10, wherein upon a change of the second network elements, the at least one first network elements is informed by the configuration function.

13. The method according to any of claims 8 to 10, wherein upon a change of the second network elements, the at least one second network element is informed by the configuration function.

14. A device comprising a and/or being associated with a processor unit and/or a hard-wired circuit and/or a logic device that is arranged such that the method according to any of the preceding claims is executable thereon .

15. The device according to claim 14, wherein said device is a communication device, in particular a or being associated with a network element or an operation and maintenance component.

16. Communication system comprising the device according to any of claims 14 or 15.