WO2014060029A1

WO2014060029A1 - Core network selection in shared network during handover/relocation

Info

Publication number: WO2014060029A1
Application number: PCT/EP2012/070554
Authority: WO
Inventors: Kati Marita Vainola
Original assignee: Nokia Siemens Networks Oy
Priority date: 2012-10-17
Filing date: 2012-10-17
Publication date: 2014-04-24

Abstract

A method for use by an apparatus of one of plural operator core networks of a communication network system which comprises a shared radio access network to which the plural operator core networks connect, decides (S11), according to a preferred subscriber distribution among the plural operator core networks, whether or not the operator core network of the apparatus is a correct target network for processing a handover/relocation request obtained (S10) by the apparatus. In case it is decided that the operator core network of the apparatus is not the correct target network, a message including the handover/relocation request is provided (S12) to another one of the plural operator core networks, which, according to the preferred subscriber distribution, is determined as the correct target network. In case it is decided that the operator core network of the apparatus is the correct target network, the handover/relocation request is processed (S13) in the operator core network of the apparatus.

Description

DESCRIPTION

TITLE

CORE NETWORK SELECTION IN SHARED NETWORK DURING HANDOVER/RELOCATION

BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates to core network selection in a shared network during handover/relocation.

Related background Art

The following meanings for the abbreviations used in this specification apply:

2G second generation

3GPP third generation partnership project

AN anchor node AP access point

BSC base station controller

BSSAP base station system application part

CN core network

CS circuit switched GPRS general packet radio services GTP GPRS tunneling protocol

GWCN gateway CN

IMSI international mobile subscriber identity

LA local area

LTE long term evolution

MAP mobile application part mobility management entity

MOCN multi operator CN

MSC mobile switching center MSS MSC server

PDU packet data unit

PLMN public land mobile network

PS packet switched

RAN radio access network RNC radio network controller

SAP service AP

SGSN serving GPRS support node

SRVCC single radio voice call continuity

TEID tunneling end ID UE user equipment

Network sharing architecture allows different core network operators to connect to a shared radio access network. There are two alternatives for network sharing: GWCN (Gateway Core Network) architecture and MOCN (Multi-Operator Core Network) architecture, as shown in Figs. 1 and 2.

Fig. 1 shows a GWCN network sharing architecture in which core network operators A, B, C each connect to shared MSC/SGSN entities which connect to RNCs of a radio access network operator X via an lu interface.

Fig. 2 shows an MOCN network sharing architecture in which the core network operators A, B, C connect to an RNC of the radio access network operator X.

When a new subscriber enters the shared network area in the MOCN configuration, the subscriber distribution is typically done in the shared radio access network according to network sharing partner agreements. For example, all the CN operator A own subscribers are directed to a core network of the CN operator A and the CN operator B subscribers are directed to a core network of the CN operator B, but for incoming roamers a different distribution can be agreed, e.g.: 20% / 80% distribution of PLMN Y subscribers and 60% / 40 % distribution of PLMN Z subscribers. In the GWCN configuration, the GWCN is able to make the corresponding subscriber distribution.

After the initial access to the shared network is done, the subscriber will be served by the chosen operator as long as he stays at the shared network area.

It is also possible, however, that the subscriber enters the shared network also by handover from another, non-shared network. In this situation, similar subscriber distribution should be enabled.

In the prior art, it is possible to define a different target MSS for different target LAI in a source MSS or MME. This enables some load distribution among the network sharing partners, if, e.g., handover/relocation towards LAM at shared area is configured to be done via a CN operator A MSS and LAI2 via a CN operator B MSS. This, however, does not enable a division of the subscribers on PLMN basis during handover/relocation, i.e., an incoming roaming subscriber, whose home network is PLMN Y, can not be distributed by the source network according to an agreed division with 60% of PLMN Y subscribers to CN operator A and 40% of PLMN Y subscribers to CN operator B.

SUMMARY OF THE INVENTION

The invention aims at overcoming the above problems. For example, the invention aims at enabling a preferred subscriber distribution to entities of a core network which connect to a shared radio access network also by handover/relocation from another, non-shared network, where the entities may be shared by different operators.

This is achieved by the methods and apparatuses defined in the appended claims. The invention may also be implemented by a computer program product.

In the following the invention will be described by way of embodiments thereof with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a GWCN architecture illustrating an example of a shared network

configuration.

Fig. 2 shows an MOCN architecture illustrating an example of a shared network configuration. Fig. 3 shows a schematic diagram illustrating the handover/relocation problem for a handover/relocation from non-shared network to shared network.

Fig. 4 shows a schematic diagram illustrating the handover/relocation problem for a handover/relocation from SRVCC PS to CS SRVCC.

Fig. 5 shows a flowchart illustrating a process 1 of selecting a correct core network in a shared network during handover/relocation according to an embodiment of the invention.

Fig. 6 shows a flowchart illustrating a process 2 of selecting a correct core network in a shared network during handover/relocation according to an embodiment of the invention.

Fig. 7 shows a flowchart illustrating a process 3 of selecting a correct core network in a shared network during handover/relocation according to an embodiment of the invention.

Fig. 8 shows a schematic diagram illustrating selection of a correct core network in a shared network during handover/relocation for 2G/3G according to an implementation example of the invention.

Fig. 9 shows a schematic diagram illustrating selection of a correct core network in a shared network during handover/relocation for SRVCC according to an implementation example of the invention.

Fig. 10 shows a schematic block diagram illustrating a configuration of control units in which examples of embodiments of the invention are implementable. DESCRIPTION OF THE EMBODIMENTS

An issue in a communication network system is how to select a target operator (and a correct MSS from a pool of MSSs if MSS pooling exists) during handover (2G) or relocation (3G) of a subscriber from a non-shared network into a shared network, when the source network is not able to differentiate the target operator among the network sharing operators.

Target operator selection in the source network can not be mandated, because the source network may be an external network which does not belong to any of the network sharing partners and contain only legacy network elements without additional capabilities. Usually, the source MSC or SGSN does not make the target core network operator selection. In other words, in case of relocation/handover to a GWCN or a MOCN, usually there is no functionality in the source MSC/SGSN to select a target core network operator or to modify the target core network operator selected by an RNC/BSC.

A setup for illustrating the 2G/3G handover/relocation problem is shown in Fig. 3. For CS, a target MSS selection is done in a source MSS of a non-shared network based on LAI (PLMN id + LA) indicated in a target identifier in a BSSAP Handover Required message received from a source BSC or a RANAP Relocation Required received from a source RNC. Only one target MSS is configured per each neighbour LAI in the source MSS, and if the target identifier received from the source BSC/RNC at the non-shared network area does not differentiate between the correct target operator PLMN (OP1 or OP2), then the MSS in the non-shared network can only choose either OP1 MSS or OP2 MSS based on its configuration. For example, if Common PLMN is indicated in LAI of the target identifier, then it has to be configured in the non-shared network MSS to either point only to OP1 MSS or only to OP2 MSS, which both serve the same shared RAN area.

Referring to Fig. 3, a UE performs handover from a non-shared network to a shared RAN area. The shared RAN area comprises a shared 2G or 3G RAN (shared RAN) in an

MOCN configuration, to which MSSs MSS1 , MSS2, MSS3 shared by operators OP1 , OP2 connect via A/lu interfaces. MSS1 OP1 , MSS2 OP1 and MSS3 OP1 belong to an MSS pool managed by OP1 , and MSS1 OP2, MSS2 OP2 and MSS3 OP2 belong to another MSS pool managed by OP2.

In step S1 , a handover/relocation need is identified for the UE at a source network which is a non-shared network and comprises an RAN to which an MSS (source MSS) connects via an A/lu interface. BSSAP Handover Required / RANAP Relocation Required message sent by the RAN (source BSC/RNC) contains either a Target Cell Identifier (handover to 2G) or Target RNC-ld (relocation to 3G). Because the target BSC or RNC is at the shared network, a PLMN identity in the Target Cell Identifier or Target RNC-ID is a Common PLMN.

In step S2, the source MSS utilizes the source BSC/RNC indicated handover/relocation target PLMN during a handover/relocation routing decision. However, because the target BSC/RNC can be accessed via all the network sharing partner core networks at the target side, but the source MSS may only make the target network selection based on its own configuration, the subscriber distribution among the target network sharing partners is not enabled.

In step S3a, for Common PLMN + LA xxx always the Operator 2 (OP2) network is selected as handover/relocation target according to the configuration of the source MSS, and it is not possible to select MSS10P1 via a MAP-E interface (step S3b) for handling the handover/relocation request, for example.

A similar problem as described above applies to SRVCC PS to CS SRVCC

relocation/handover. The source network is not able, or mandated to, make the target network selection during handover/relocation to the shared network. A source MME does not make a target core network operator selection. At SRVCC the MME selects an MSC based on a selected target PLMN indicated by an eNodeB. A setup for illustrating the SRVCC handover/relocation problem is shown in Fig. 4. A VoLTE UE performs a PS to CS SRVCC relocation/handover from a non-shared network to a shared RAN area. The shared RAN area comprises a shared 2G or 3G RAN (shared RAN) in an MOCN configuration, to which MSSs MSS1 , MSS2, MSS3 shared by operators OP1 , OP2 connect via A/lu interfaces. MSS1 OP1 , MSS2 OP1 and MSS3 OP1 belong to an MSS pool managed by OP1 , and MSS1 OP2, MSS2 OP2 and MSS3 OP2 belong to another MSS pool managed by OP2.

In step C1 , a handover/relocation need is identified at the source network. Similarly as in 2G/3G, a source MME connected to an eNb of the non-shared network gets a handover target indication in form of a Target Cell Identifier (handover to 2G) or a Target RNC-ld (relocation to 3G). Because a target BSC or RNC is at the shared network, a PLMN identity in the Target Cell Identifier or Target RNC-ID is the Common PLMN.

In step C2, the source MME utilizes the indicated handover/relocation target PLMN during a handover/relocation routing decision. However, because the target BSC/RNC can be accessed via all the network sharing partner core networks at the target side, but the source MME may only make the target network selection based on its own configuration, the subscriber distribution among the target network sharing partners is not enabled.

In step C3a, for the Common PLMN + LA xxx always the Operator 2 (OP2) network is selected as handover/relocation target according to the configuration of the source MME, and it is not possible to select MSS10P1 via an Sv (GTP) interface (step C3b) for handling the handover/relocation request, for example.

Therefore, a new method is required at the target network side to balance the subscriber distribution during handover/relocation to be according to agreements made by the network sharing partners. According to the invention, the final routing decision is left for the target network during handover/relocation. A target MSS is enabled to decide e.g. based on IMSI analysis to which network sharing partner a handed over/relocated subscriber should belong to.

Based on IMSI analysis, a desired amount of certain PLMN subscribers may be be directed to another MSS, which may reside in the network sharing partner's core network.

Fig. 5 shows a flowchart illustrating a process 1 of selecting a correct core network in a shared network during handover/relocation. The process 1 may be performed by an apparatus of one of plural operator core networks of a communication network system which comprises a shared radio access network to which the plural operator core networks connect, e.g. a shared MSC/SGSN, MSS, or the like.

In step S10, a handover/relocation request (e.g. a MAP-E interface Handover/Relocation Request, or an Sv interface SRVCC PS to CS Request) is obtained by the apparatus, e.g. from a switching device (e.g. an MSS, MME, or the like) of a non-shared network.

In step S1 1 , it is decided, according to a preferred subscriber distribution among the plural operator core networks, whether or not the operator core network of the apparatus is a correct target network for processing the handover/relocation request.

In step S12, in case it is decided that the operator core network of the apparatus is not the correct target network, a message including the handover/relocation request is provided to another one of the plural operator core networks, which, according to the preferred subscriber distribution, is determined as the correct target network. A handover/relocation acknowledge message (e.g. a MAP-E interface Handover Request/Relocation Request message) may be provided to the switching device in response to the handover/relocation request, in case the correct target network (or correct target apparatus at the correct target network processing the request) has no interface to the switching device. Otherwise, in step S13, in case it is decided that the operator core network of the apparatus is the correct target network, the handover/relocation request is processed in the operator core network of the apparatus.

For example, in 2G/3G handover/relocation and in SRVCC handover/relocation, a target network makes the decision to forward handover/relocation signaling to the correct target network according to the preferred subscriber distribution among the network sharing partners.

Fig. 6 shows a flowchart illustrating a process 2 of selecting a correct core network in a shared network during handover/relocation. The process 2 may be performed by the above-mentioned switching device, e.g. an MSS or MME of a non-shared network of the communication network system.

In step S20, it is detected that handover/relocation of the subscriber to the shared radio access network is requested. In step S21 , the handover/relocation request is provided to a target operator core network of the plural operator core networks, for controlling the handover/relocation. In case several apparatuses for processing the handover/relocation request are in use in the target operator core network, the handover/relocation request is provided to a target apparatus in the target operator core network for controlling the handover/relocation.

At the target (apparatus in the) operator core network (in process 1 ), a home mobile network of the subscriber to be handed-over/relocated by the handover/relocation request may be identified, and the correct target network may be decided based on the home mobile network of the subscriber and mobile network specific weight factors representing the preferred subscriber distribution. In case several apparatuses for processing the handover/relocation request are in use in the correct target network, a correct target apparatus for processing the handover/relocation request in the correct target network may be detected based on the home mobile network of the subscriber and weight factors representing a preferred subscriber distribution in the correct target network, and the message may be provided to the correct target apparatus.

According to an embodiment of the invention, information elements available from the handover/relocation request are included into the message provided to the correct target network/apparatus in step S12 in process 1 , which identify the switching device from which the handover/relocation request has been obtained.

Further, in case the message including the handover/relocation request has been provided to the correct target network/apparatus, a notification to cancel

handover/relocation requested by the handover/relocation request may be indicated to the correct target network/apparatus in case a cancel notification message is obtained by the target apparatus from the switching device, to cancel the handover/relocation, and a cancel acknowledge message may be provided to the switching device in response to the cancel notification message.

Fig. 7 shows a flowchart illustrating a process 3 of selecting a correct core network in a shared network during handover/relocation. The process 3 may be performed by the correct target network/apparatus in the other network (correct target network) to which the handover/relocation request is provided.

In step S30, the message including the handover/relocation request is obtained. In step S31 , the handover/relocation request is processed. The information elements may be extracted from the message, which identify the switching device from which the handover/relocation request has been obtained, and a handover/relocation acknowledge message (e.g. SRVCC PS to CS Response message) may be provided towards the switching device e.g. via an Sv interface. Upon obtaining a notification to cancel handover/relocation requested by the handover/relocation request, from the apparatus from which the message has been obtained (i.e. the target apparatus), the

handover/relocation may be cancelled and a cancel acknowledge message may be provided to the switching device. For example, for SRVCC handover/relocation, the correct source MME where to send the SRVCC PS to CS Response message over the Sv interface can be identified after handover/relocation forwarding at the target network has been done. New information elements "MME/SGSN Sv Address for Control Plane" and "MME/SGSN Sv TEID for Control Plane" may be included in a MAP-E interface signaling in a

MAP_PREPARE_HANDOVER Request to indicate the source MME, when the handover/relocation message is forwarded as shown in step S12 in process 1. These new information elements may be transferred in the MAP_PREPARE_HANDOVER Request as separate lEs at the MAP level message, or they may be included in an AN-APDU IE together with the whole received Sv interface SRVCC PS to CS Request message.

Further, for SRVCC handover/relocation, a method is provided to manage

handover/relocation cancellation during handover/relocation request forwarding.

As shown in Fig. 8, a UE performs handover from a non-shared network to a shared RAN area. The shared RAN area comprises a shared 2G or 3G RAN (shared RAN) in an MOCN configuration, to which MSSs MSS1 , MSS2, MSS3 shared by operators OP1 , OP2 connect via A/lu interfaces. MSS1 OP1 , MSS2 OP1 and MSS3 OP1 belong to an MSS pool managed by OP1 , and MSS1 OP2, MSS2 OP2 and MSS3 OP2 belong to another MSS pool managed by OP2.

In step S'1 , a handover/relocation need is identified at the source network, i.e. the nonshared network comprising a RAN and an MSS (source MSS) connected to the RAN via an A lu interface. A BSSAP Handover Required / RANAP Relocation Required message is sent by the source BSC/RNC (the RAN) to the MSS and it contains either a Target Cell Identifier (handover to 2G) or a Target RNC-ld (relocation to 3G). Because the target BSC or RNC (shared RAN) is at the shared network, a PLMN identity in the Target Cell Identifier or Target RNC-ID is the Common PLMN.

In step S'2, the source MSS utilizes the source BSC/RNC indicated handover/relocation target PLMN during a handover/relocation routing decision based on the received Common PLMN + LA xxx target identifier. According to the routing configuration in source MSS, MSS1 in OP2 network (MSS1 OP2) is selected as handover/relocation target during MAP_PREPARE_HANDOVER Request.

In step S'3, when the MSS1 OP2 receives a MAP-E interface Handover

Request/Relocation Request message (the MAP_PREPARE_HANDOVER Request), it evaluates if it is the correct target MSS or if the handover/relocation should be forwarded to another MSS. The target evaluation in the MSS1 OP2 may be based on the subscriber PLMN in a way which enables subscriber distribution as agreed by the network sharing partners, e.g. 20% / 80% distribution of PLMN Y subscribers and 60% / 40 % distribution of PLMN Z subscribers.

In this example case, the MSS1 OP2 identifies the need to forward the MAP-E interface Handover Request/Relocation Request message to the network sharing partner MSS1 OP1 , and in step S'4 the MAP_PREPARE_HANDOVER Request is forwarded to the MSS1 OP1.

In step S'5, when the MSS1 OP1 receives the message, it evaluates itself as the correct target MSS for the handover/relocation. The MSS1 OP1 continues the inter-MSS handover as normally for the subscriber, and sends a Handover Request Acknowledge / Relocation Request Acknowledge in MAP_PREPARE_HAN DOVER Response directly to the original source MSS in the non-shared network. Fig. 9 shows a schematic diagram illustrating selection of a correct core network in a shared network during handover/relocation for SRVCC according to an implementation example of the invention.

As shown in Fig. 9, a VoLTE UE performs a PS to CS SRVCC relocation/handover from a non-shared network to a shared RAN area. The shared RAN area comprises a shared 2G or 3G RAN (shared RAN) in an MOCN configuration, to which MSSs MSS1 , MSS2, MSS3 shared by operators OP1 , OP2 connect via A/lu interfaces. MSS1 OP1 , MSS2 OP1 and MSS3 OP1 belong to an MSS pool managed by OP1 , and MSS1 OP2, MSS2 OP2 and MSS3 OP2 belong to another MSS pool managed by OP2.

In step C'1 , a PS to CS SRVCC relocation/handover need is identified at a source network, e.g. a non-shared network comprising an eNB and an MME connecting to the eNB. The source eNB indicates a target identifier as either a Target Cell Identifier (handover to 2G) or a Target RNC-ld (relocation to 3G). Because a target BSC or RNC is at the shared network, a PLMN identity in the Target Cell Identifier or Target RNC-ID is the Common PLMN.

In step C'2, the source MME utilizes the source eNB indicated handover/relocation target PLMN during a PS to CS SRVCC relocation/handover routing decision based on the received Common PLMN + LA xxx target identifier. According to the routing configuration in the source MME, MSS1 in OP2 network (MSS1 OP2) is selected as

handover/relocation target.

In step C'3, when the MSS1 OP2 receives the Sv interface SRVCC PS to CS Request message, it evaluates if it is the correct target MSS or if the handover/relocation should be forwarded to another MSS. The target evaluation in the MSS1 OP2 may be based on the subscriber PLMN in a way which enables a subscriber distribution as agreed by the network sharing partners, e.g. 20% / 80% distribution of PLMN Y subscribers and 60% / 40 % distribution of PLMN Z subscribers. In this example case, the MSS1 0P2 identifies the need to forward the Sv interface SRVCC PS to CS Request message to the network sharing partner MSS1 OP1 . When the MSS1 OP1 forwards the request in step C'4, it may include new lEs to the

MAP_PREPARE_HANDOVER Request: MME/SGSN Sv Address for Control Plane and MME/SGSN Sv TEID for Control Plane at the MAP level. These lEs are available from the original SRVCC PS to CS Request message received from the MME. In addition, the MAP_PREPARE_HANDOVER Request may include the information from the original Sv interface SRVCC PS to CS Request message either in an AN-APDU IE (whole original Sv interface message may be included), or as new separate lEs at the MAP level message.

When MSS1 OP1 receives the message, it evaluates itself as the correct target MSS for the handover/relocation. The MSS1 OP1 continues the relocation/handover procedure as normally for the subscriber, and in step C'5 sends an Sv interface SRVCC PS to CS Response message directly to the original source MME in the non-shared network based on the MME/SGSN Sv Address for Control Plane and MME/SGSN Sv TEID for Control Plane received in the MAP_PREPARE_HANDOVER Request.

With the above-described new information elements, it is possible to route the SRVCC PS to CS Response message directly to the original source MME in the non-shared network and avoid the signaling messages to be passed via the MSS1 OP2. In this way it is prevented that the MSS1 OP2 unnecessarily remains at the signaling path as an anchor. In the SRVCC PS to CS Response message to the MME, the MSS1 OP1 may include "MSC Server Sv Address for Control Plane" and "MSC Server Sv TEID for Control Plane" lEs, based on which the MME knows where to send the subsequent control plane messages to this GTP-C tunnel.

It is possible that the source radio network decides to initiate a PS to CS SRVCC relocation/handover cancel procedure when the Sv interface SRVCC PS to CS Request message has been sent, but the correct target MSS has not yet responded with the Sv interface SRVCC PS to CS Response message. When the original target MSS (MSS1 OP2) receives the SRVCC PS to CS Cancel Notification message, the situation may be indicated also to the MSS1 OP1 using existing methods defined at MAP-E interface. The original target MSS (MSS1 OP2) may also respond to the MME with a SRVCC PS to CS Cancel Acknowledge message.

If, however, there is no Sv interface connectivity from the MSS1 OP1 to the MME of the non-shared network, then the MSS1 OP2 may be used as an anchor MSS during the SRVCC PS to CS relocation/handover procedure.

To enable incoming subscriber distribution according to an agreed share of subscribers for 2G/3G and SRVCC, the correct target MSS decision may be based on PLMN specific weight factors, for example.

When the incoming subscriber home PLMN is solved by IMSI analysis, this information combined with PLMN weight factors can be used to derive the correct target operator and the MSS element if MSS pooling is in use in the correct target operator network.

If the subscriber is decided to be kept in the own network, then weight factors can also be used to choose the correct target MSS from the own network if MSS pooling in the own network is in use.

It is to be noted that the example signaling scenarios are presented from CS core viewpoint, however the same situation applies for PS core when a target RAN is shared (during Relocation procedure in 3G and PS handover in 2G) and thus the solutions shown in Figs. 5-7 can also be applied to PS core.

Now reference is made to Fig. 10 for illustrating a simplified block diagram of various electronic devices that are suitable for use in practicing the exemplary embodiments of this invention. A control unit 10, which may execute process 1 shown in Fig. 5 and/or may be included in or be part of the MSS1 OP2 shown in Figs. 8 and 9, comprises processing resources 1 1 , memory resources 12 which may store a program, and interfaces 13, which are connected by a link 14.

A control unit 20, which may execute process 3 shown in Fig. 7 and/or may be included in or be part of the MSS1 OP1 shown in Figs. 8 and 9, comprises processing resources 21 , memory resources 22 which may store a program, and interfaces 23, which are connected by a link 24.

A control unit 30, which may execute process 2 shown in Fig. 6 and/or may be included in or be part of the MSS/MME of the non-shared network shown in Figs. 8 and 9, comprises processing resources 31 , memory resources 32 which may store a program, and interfaces 33, which are connected by a link 34.

The control unit 10 and the control unit 20 are connected through their interfaces 13, 23 via a link 41 , e.g. for providing a MAP-E interface handover/relocation request message from the control unit 10 to the control unit 20.

The control unit 10 and the control unit 30 are connected through their interfaces 13, 33 via a link 42, e.g. for providing a MAP-E interface handover/relocation request or an Sv interface SRVCC PS to CS request from the control unit 30 to the control unit 10.

The control unit 20 and the control unit 30 are connected through their interfaces 23, 33 via a link 43, e.g. for providing a MAP-E interface handover/relocation response or an Sv interface SRVCC PS to CS response from the control unit 20 to the control unit 30. The terms "connected," "coupled," or any variant thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are

"connected" or "coupled" together. The coupling or connection between the elements can be physical, logical, or a combination thereof. As employed herein two elements may be considered to be "connected" or "coupled" together by the use of one or more wires, cables and printed electrical connections, as well as by the use of electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, the microwave region and the optical (both visible and invisible) region, as non-limiting examples.

In general, the exemplary embodiments of this invention may be implemented by computer software stored in the memory resources 12, 22, 32 and executable by the processing resources 1 1 , 21 , 31 , or by hardware, or by a combination of software and/or firmware and hardware in any or all of the devices shown.

The memory resources 12, 22, 32 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The processing resources 1 1 , 21 , 31 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples.

According to an aspect of the invention, an apparatus of one of plural operator core networks of a communication network system which comprises a shared radio access network to which the plural operator core networks connect, which may comprise or use the control unit 10, comprises means for deciding, according to a preferred subscriber distribution among the plural operator core networks, whether or not the operator core network of the apparatus is a correct target network for processing a handover/relocation request obtained by the apparatus, and means for, in case it is decided that the operator core network of the apparatus is not the correct target network, providing a message including the handover/relocation request to another one of the plural operator core networks, which, according to the preferred subscriber distribution, is determined as the correct target network, and means for, in case it is decided that the operator core network of the apparatus is the correct target network, processing the handover/relocation request by the operator core network of the apparatus.

The apparatus may comprise means for identifying a home mobile network of a subscriber to be handed-over/relocated by the handover/relocation request. The means for deciding may decide the correct target network based on the home mobile network of the subscriber and mobile network specific weight factors representing the preferred subscriber distribution. In case several apparatuses for processing the

handover/relocation request are in use in the correct target network, the means for deciding may decide a correct target apparatus for processing the handover/relocation request in the correct target network based on the home mobile network of the subscriber and weight factors representing a preferred subscriber distribution in the correct target network, and the means for providing may provide the message to the correct target apparatus.

The means for providing may including information elements available from the

handover/relocation request into the message, which identify a switching device from which the apparatus has obtained the handover/relocation request.

The means for providing may include the information elements together with the handover/relocation request in an anchor node anchor packet data unit information element or as further information elements at a mobile application part level.

The apparatus may comprise means for, in case the message including the

handover/relocation request has been provided to the correct target network/apparatus, indicating a notification to cancel handover/relocation requested by the

handover/relocation request, to the correct target network/apparatus in case a cancel notification message is obtained by the apparatus, to cancel the handover/relocation, and the means for providing may provide a cancel acknowledge message in response to the cancel notification message.

The means for providing may provide a handover/relocation acknowledge message to a switching device from which the apparatus has obtained the handover/relocation request, in response to the handover/relocation request, in case the correct target

network/apparatus has no interface to the switching device.

The means for deciding, providing, processing, identifying and indicating may be implemented by the processing resources 1 1 , memory resources 12 and interfaces 13.

According to an aspect of the invention, an apparatus of one of plural operator core networks of a communication network system which comprises a shared radio access network to which the plural operator core networks connect, which may comprise or use the control unit 20, comprises means for obtaining a message including a

handover/relocation request, from another apparatus of one of the plural operator core networks, and means for processing the handover/relocation request.

The apparatus may comprise means for extracting information elements from the message, which identify a switching device from which the handover/relocation request has been obtained, and means for providing a handover/relocation acknowledge message towards the switching device.

The apparatus may comprise means for, upon obtaining a notification to cancel handover/relocation requested by the handover/relocation request, from the other apparatus, cancelling the handover/relocation and the means for providing may provide a cancel acknowledge message to the switching device. The means for obtaining, processing, extracting, providing and cancelling may be implemented by the processing resources 21 , memory resources 22 and interfaces 23.

According to an aspect of the invention, a switching device of a communication network system, which may comprise or use the control unit 30, comprises means for detecting that handover/relocation of a subscriber to a shared radio access network is requested, to which plural operator core networks connect, and means for providing a

handover/relocation request to a target operator core network of the plural operator core networks, for controlling the handover/relocation. In case several apparatuses for processing the handover/relocation request are in use in the target operator core network, the means for providing may provide the handover/relocation request to a target apparatus in the target operator core network for controlling the handover/relocation.

The means for detecting and providing may be implemented by the processing resources 31 , memory resources 32 and interfaces 33.

The handover/relocation request may be at least one of a mobile application part E interface handover/relocation request and an Sv interface single radio voice call continuity packet switched to circuit switched request. The message including the

handover/relocation request may be a mobile application part prepare handover request.

It is to be understood that the above description is illustrative of the invention and is not to be construed as limiting the invention. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.

Claims

CLAIMS:

1. A method for use by an apparatus of one of plural operator core networks of a communication network system which comprises a shared radio access network to which the plural operator core networks connect, the method comprising: deciding, according to a preferred subscriber distribution among the plural operator core networks, whether or not the operator core network of the apparatus is a correct target network for processing a handover/relocation request obtained by the apparatus; and in case it is decided that the operator core network of the apparatus is not the correct target network, providing a message including the handover/relocation request to another one of the plural operator core networks, which, according to the preferred subscriber distribution, is determined as the correct target network, and in case it is decided that the operator core network of the apparatus is the correct target network, processing the handover/relocation request in the operator core network of the apparatus.

2. The method of claim 1 , comprising: identifying a home mobile network of a subscriber to be handed-over/relocated by the handover/relocation request; deciding the correct target network based on the home mobile network of the subscriber and mobile network specific weight factors representing the preferred subscriber distribution; and in case several apparatuses for processing the handover/relocation request are in use in the correct target network, deciding a correct target apparatus for processing the handover/relocation request in the correct target network based on the home mobile network of the subscriber and weight factors representing a preferred subscriber distribution in the correct target network, and providing the message to the correct target apparatus.

3. The method of claim 1 or 2, the providing comprising: including information elements available from the handover/relocation request into the message, which identify a switching device from which the apparatus has obtained the handover/relocation request.

4. The method of claim 3, wherein the information elements are included together with the handover/relocation request in an anchor node anchor packet data unit information element or as further information elements at a mobile application part level.

5. The method of any one of claims 1 to 4, comprising: in case the message including the handover/relocation request has been provided to the correct target network/apparatus, indicating a notification to cancel

handover/relocation requested by the handover/relocation request, to the correct target network/apparatus in case a cancel notification message is obtained by the apparatus, to cancel the handover/relocation; and providing a cancel acknowledge message in response to the cancel notification message.

6. The method of any one of claims 1 to 5, comprising: providing a handover/relocation acknowledge message to a switching device from which the apparatus has obtained the handover/relocation request, in response to the handover/relocation request, in case the correct target network/apparatus has no interface to the switching device.

7. A method for use by an apparatus of one of plural operator core networks of a communication network system which comprises a shared radio access network to which the plural operator core networks connect, the method comprising: obtaining a message including a handover/relocation request, from another apparatus of one of the plural operator core networks; and processing the handover/relocation request.

8. The method of claim 7, comprising: extracting information elements from the message, which identify a switching device from which the handover/relocation request has been obtained; and providing a handover/relocation acknowledge message towards the switching device.

9. The method of claim 8, comprising: upon obtaining a notification to cancel handover/relocation requested by the handover/relocation request, from the other apparatus, cancelling the handover/relocation and providing a cancel acknowledge message to the switching device.

10. A method for use by a switching device of a communication network system, the method comprising: detecting that handover/relocation of a subscriber to a shared radio access network is requested, to which plural operator core networks connect; and providing a handover/relocation request to a target operator core network of the plural operator core networks, for controlling the handover/relocation, or in case several apparatuses for processing the handover/relocation request are in use in the target operator core network, providing the handover/relocation request to a target apparatus in the target operator core network for controlling the

handover/relocation.

1 1 . The method of any one of claims 1 to 10, wherein - the handover/relocation request is at least one of a mobile application part E interface handover/relocation request and an Sv interface single radio voice call continuity packet switched to circuit switched request, and/or

- the message including the handover/relocation request is a mobile application part prepare handover request.

12. A computer program product including a program for a processing device, comprising software code portions for performing the steps of any one of claims 1 to 1 1 when the program is run on the processing device.

13. The computer program product according to claim 12, wherein the computer program product comprises a computer-readable medium on which the software code portions are stored.

14. The computer program product according to claim 12, wherein the program is directly loadable into an internal memory of the processing device.

15. An apparatus of one of plural operator core networks of a communication network system which comprises a shared radio access network to which the plural operator core networks connect, the apparatus being configured to: decide, according to a preferred subscriber distribution among the plural operator core networks, whether or not the operator core network of the apparatus is a correct target network for processing a handover/relocation request obtained by the apparatus; and in case the apparatus decides that the operator core network of the apparatus is not the correct target network, provide a message including the handover/relocation request to another one of the plural operator core networks, which, according to the preferred subscriber distribution, is determined by the apparatus as the correct target network, and in case the apparatus decides that the operator core network of the apparatus is the correct target network, process the handover/relocation request in the operator core network of the apparatus.

16. The apparatus of claim 15, configured to: identify a home mobile network of a subscriber to be handed-over/relocated by the handover/relocation request; decide the correct target network based on the home mobile network of the subscriber and mobile network specific weight factors representing the preferred subscriber distribution; and in case several apparatuses for processing the handover/relocation request are in use in the correct target network, decide a correct target apparatus for processing the handover/relocation request in the correct target network based on the home mobile network of the subscriber and weight factors representing a preferred subscriber distribution in the correct target network, and provide the message to the correct target apparatus.

17. The apparatus of claim 15 or 16, configured to: when providing the message, include information elements available from the handover/relocation request into the message, which identify a switching device from which the apparatus has obtained the handover/relocation request.

18. The apparatus of claim 17, wherein the apparatus is configured to include the information elements together with the handover/relocation request in an anchor node anchor packet data unit information element or as further information elements at a mobile application part level.

19. The apparatus of any one of claims 15 to 18, configured to: in case the message including the handover/relocation request has been provided to the correct target network/apparatus, indicate a notification to cancel

handover/relocation requested by the handover/relocation request, to the correct target network/apparatus in case a cancel notification message is obtained by the apparatus, to cancel the handover/relocation; and provide a cancel acknowledge message in response to the cancel notification message.

20. The apparatus of any one of claims 15 to 19, configured to: provide a handover/relocation acknowledge message to a switching device from which the apparatus has obtained the handover/relocation request, in response to the handover/relocation request, in case the correct target network/apparatus has no interface to the switching device.

21 . An apparatus of one of plural operator core networks of a communication network system which comprises a shared radio access network to which the plural operator core networks connect, the apparatus being configured to: obtain a message including a handover/relocation request, from another apparatus of one of the plural operator core networks; and process the handover/relocation request.

22. The apparatus of claim 21 , configured to: extract information elements from the message, which identify a switching device from which the handover/relocation request has been obtained; and provide a handover/relocation acknowledge message towards the switching device.

23. The apparatus of claim 22, configured to: upon obtaining a notification to cancel handover/relocation requested by the handover/relocation request, from the other apparatus, cancel the handover/relocation and provide a cancel acknowledge message to the switching device.

24. A switching device of a communication network system, the switching device being configured to: detect that handover/relocation of a subscriber to a shared radio access network is requested, to which plural operator core networks connect; and provide a handover/relocation request to a target operator core network of the plural operator core networks, for controlling the handover/relocation, or in case several apparatuses for processing the handover/relocation request are in use in the target operator core network, provide the handover/relocation request to a target apparatus in the target operator core network for controlling the

handover/relocation.