WO2017135858A1

WO2017135858A1 - Radio network nodes and methods performed therein

Info

Publication number: WO2017135858A1
Application number: PCT/SE2016/050105
Authority: WO
Inventors: Elena MYHRE; Jari Vikberg; Oscar Zee; Walter Müller
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2016-02-05
Filing date: 2016-02-12
Publication date: 2017-08-10

Abstract

Embodiments herein relate to a method performed by a first radio network node (12) for handling communication for a wireless device (10) in a communication network (1). The communication network (1) comprises a first core network and a second core network connected to one or more radio access networks with the first radio network node and a second radio network node (16). The communication network (1) comprises partitioned sets of functionalities wherein a first set of functionalities belongs to a first network slice supporting the wireless device (10) of a first core network node (13) in the first core network, and a second set of functionalities belongs to a second network slice supporting the wireless device (10) of a second core network node (14) in the second core network.

Description

RADIO NETWORK NODES AND METHODS PERFORMED THEREIN

TECHNICAL FIELD

Embodiments herein relate to a first radio network node, a second radio network node and methods performed therein for communication. Furthermore, a computer program and a computer readable storage medium are also provided herein. In particular, embodiments herein relate to handling communication for a wireless device in a communication network. BACKGROUND

In a typical communication network, wireless devices, also known as wireless communication devices, mobile stations, stations (STA) and/or user equipments (UE), communicate via a Radio Access Network (RAN) to one or more core networks (CN). The RAN covers a geographical area which is divided into service areas or cell areas, with each service area or cell area being served by a radio network node such as a radio access node e.g., a Wi-Fi access point or a radio base station (RBS), which in some networks may also be denoted, for example, a "NodeB" or "eNodeB". A service area or cell area is a geographical area where radio coverage is provided by the radio network node. The radio network node communicates over an air interface operating on radio frequencies with the wireless device within range of the radio network node.

A Universal Mobile Telecommunications System (UMTS) is a third generation (3G) telecommunication network, which evolved from the second generation (2G) Global System for Mobile Communications (GSM). The UMTS terrestrial radio access network (UTRAN) is essentially a RAN using wideband code division multiple access (WCDMA) and/or High Speed Packet Access (HSPA) for user equipments. In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for third generation networks, and investigate enhanced data rate and radio capacity. In some RANs, e.g. as in UMTS, several radio network nodes may be connected, e.g., by landlines or microwave, to a controller node, such as a radio network controller (RNC) or a base station controller (BSC), which supervises and coordinates various activities of the plural radio network nodes connected thereto. This type of connection is sometimes referred to as a backhaul connection. The RNCs and BSCs are typically connected to one or more core networks. Specifications for the Evolved Packet System (EPS), also called a Fourth

Generation (4G) network, have been completed within the 3^rd Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases, for example to specify a Fifth Generation (5G) network. The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also known as the Long Term Evolution (LTE) radio access network, and the Evolved Packet Core (EPC), also known as System Architecture Evolution (SAE) core network. E-UTRAN/LTE is a variant of a 3GPP radio access network wherein the radio network nodes are directly connected to the EPC core network rather than to RNCs. In general, in E-UTRAN/LTE the functions of an RNC are distributed between the radio network nodes, e.g. eNodeBs in LTE, and the core network. As such, the RAN of an EPS has an essentially "flat" architecture comprising radio network nodes connected directly to one or more core networks, i.e. they are not connected to RNCs. To compensate for that, the E-UTRAN specification defines a direct interface between the radio network nodes, this interface being denoted the X2 interface. EPS is the Evolved 3GPP Packet Switched Domain. Fig. 1 is an overview of the EPC architecture. This architecture is defined in 3GPP TS 23.401 v.13.4.0 wherein a definition of a Packet Data Network Gateway (P-GW), a Serving Gateway (S-GW), a Policy and Charging Rules Function (PCRF), a Mobility Management Entity (MME) and a wireless or mobile device (UE) is found. The LTE radio access, E-UTRAN, comprises one or more eNBs. Fig. 2 shows the overall E-UTRAN architecture and is further defined in for example 3GPP TS 36.300 v.13.1.0. The E-UTRAN comprises eNBs, providing a user plane comprising the protocol layers Packet Data Convergence Protocol (PDCP)/Radio Link Control (RLC)/Medium Access Control (MAC)/Physical layer (PHY), and a control plane comprising Radio Resource Control (RRC) protocol in addition to the user plane protocols towards the wireless device. The radio network nodes are interconnected with each other by means of the X2 interface. The radio network nodes are also connected by means of the S1 interface to the EPC, more specifically to the MME by means of an SIMM E interface and to the S-GW by means of an S1-U interface.

The third generation partnership project (3GPP) is currently working on standardization of Release 13 of the LTE concept. The architecture of the LTE system is shown in Fig. 3, including radio network nodes e.g. eNBs, Home eNBs (HeNBs), HeNB GW, and evolved packet core nodes, e.g. MMEs or S-GWs. An S1 interface connects HeNBs/eNBs to the MME/S-GW and HeNBs to the HeNB GW, while an X2 interface connects peer eNBs/HeNBs, optionally via an X2 GW. The S1-MME interface is used for control plane between eNodeB/E-UTRAN and MME. The main protocols used in this interface are S1 Application Protocol (S1-AP) and Stream Control Transmission Protocol (SCTP). S1AP is the application layer protocol between the radio network node and the MME and SCTP for example guarantees delivery of signaling messages between MME and the radio network node. The transport network layer is based on Internet Protocol (IP).

A subset of the S1 interface provided functions are:

S1 -interface management functions such as S1 setup, error indication, reset and the radio network node and MME configuration update.

- UE Context Management functionality such as Initial Context Setup Function and UE Context Modification Function.

E-UTRAN Radio Access Bearer (E-RAB) Service Management functions e.g. Setup, Modify, Release.

Mobility Functions for wireless devices in EPS Connection Management (ECM)-CONNECTED, e.g. Intra-LTE Handover and inter-3GPP-Radio Access

Technology (RAT) Handover.

S1 Paging function.

Non Access Stratum (NAS) Signaling Transport function.

Establishment of the S1-MME interface on S1AP protocol level is shown in Fig. 4 as the S1 setup procedure. The purpose of the S1 Setup procedure is to exchange application level data needed for the radio network node and the MME to correctly interoperate on the S1 interface. The radio network node may initiate the procedure by sending an S1 SETUP REQUEST message to the MME once it has gained IP

connectivity and it has been configured with at least one Tracking Area Indicator (TAI). The TAI(s) are used by the radio network node to locate IP-addresses of the different MMEs, possibly in different MME pools. The radio network node includes its global radio network node identity and other information in the S1 SETUP REQUEST message. The MME responds with an S1 SETUP RESPONSE message. This S1 SETUP RESPONSE message includes for example the Globally Unique MME identifier(s) (GUMMEI) of the MME.

An Initial Context Setup process is shown in Fig. 5. An INITIAL CONTEXT SETUP REQUEST message is sent by the MME to request the setup of a UE context or context of a wireless device. This INITIAL CONTEXT SETUP REQUEST message comprises information related to both the UE context and different E-RABs to be established. For each E-RAB the MME includes E-RAB Quality of Service (QoS) parameters such as QoS Class Identifier (QCI) and Allocation and Retention Priority (ARP). The QCI is a scalar that is used as a reference to radio access node-specific parameters that control bearer level packet forwarding treatment, e.g. scheduling weights, admission thresholds, queue management thresholds, link layer protocol configuration, etc., and that have been pre- configured by the operator owning the radio network node. An INITIAL CONTEXT SETUP RESPONSE message is sent by eNB to the MME confirming the setup. Current assumption is that the RAN-CN split is similar for 5G as for 4G, implying an (evolved) S1 interface.

The wireless communication industry is at the verge of a unique business crossroads. The growing gap between capacity and demand is an urgent call for new approaches and alternative network technologies to enable mobile operators to achieve more with less. Today, mobile broadband data is growing at an annual rate of 40-50 percent per year in the U.S. and other regions globally. Mobile service providers address these rapidly expanding traffic volumes through deployment of additional network functions, which will be a significant capital expenditure (CAPEX) challenge. The nature of the mobile broadband data traffic is also evolving with new services including new video applications, connected cars and the Internet of Things (loT). This rapid capacity growth and increasing traffic diversity in LTE networks stresses the assumptions of existing network architectures and operational paradigms.

Network Functions Virtualization (NFV) provides a new path that can increase the flexibility required by mobile service providers and network operators to adapt and accommodate this dynamic market environment. NFV is a new operational approach applying well-known virtualization technologies to create a physical Commercial Off-the- Shelf (COTS) distributed platform for the delivery of end-to-end services in the context of the demanding environment of telecom network infrastructure and applications.

Because EPC is critical to the realization and management of all LTE traffic, it is important to consider use cases related to virtualization of the EPC elements. Each individual EPC element also has specific considerations that determine whether to deploy with NFV. Virtualized EPC (vEPC) is a good example: Multiple virtualized network functions (VNF) can be deployed and managed on a Network Functions Virtualization Infrastructure (NFVI) but must cater to performance scalability in both signaling/control plane and user plane, each potentially demanding different levels of NFVI resources. vEPC elements can benefit from more agile deployment and scalability. However, virtual resource monitoring and orchestration, along with service awareness, are essential for implementing elasticity effectively. Due to the nature of telecom networks, service Level Agreements (SLA) will be a key issue for a virtualized mobile core network.

Because virtualization usually leads to a performance trade-off, equipment vendors must optimize data-plane processing to satisfy carrier-grade bandwidth and latency requirements and sufficient control-plane performance for SLAs needed to ensure availability of regulatory services, such as emergency calls.

VNF is a virtualized network function which serves as a VNF Software for providing virtual network capabilities. A VNF could be decomposed and instantiated in roles such as Virtualized MME (vMME), Virtualized PCRF (vPCRF), Virtualized SGW (vSGW) or Virtualized PDN-GW (vPDN-GW).

NFV is seen as an enabler for network slicing that is described herein.

When looking at the wide range of applications and use cases that are addressed with a 5G network, it is quite obvious these cannot effectively be addressed with a traditional approach of having a purpose built network for each application. This will lead to high cost for networks and devices as well as inefficient use of valuable frequency resources. An operator may have one physical network infrastructure and one pool of frequency bands, which may support many separate virtualized networks, also called network slices. Each network slice may have unique characteristics for meeting the specific requirements of the use case/s it serves.

A key function of 5G Core network is to allow for flexibility in network service creation, making use of different network functions suitable for the offered service in a specific network slice, e.g. Evolved Mobile Broadband (MBB), Massive Machine Type Communication (MTC), Critical MTC, Enterprise, etc.

In addition to Service optimized networks there are more drivers for Network slicing, such as;

- Business expansion by low initial investment: Given the physical

infrastructure it is much easier to instantiate another Packet Core instance for the business expansion than to set up a new parallel infrastructure or even integrated nodes

Low risk by no/limited impact on legacy: As the new instance is logically separated from the other network slices, the network slices can also provide resource isolation between each other. Thus introduction of a new isolated network slice will not impact the existing operator services and therefore only provide low risk

Short Time To Market (TTM): The operators are concerned about the time it takes to set up the network for a new service. Slicing of the network for different services/operator use cases provides a separation of concern that can result in a faster setup of a network slice for a certain service as it is separately managed and with limited impact on other network slices Optimized use of resources: Today the network is supporting many different services but with new use cases and more diverging requirements there is a need for optimizing the network for the specific type use case. Network slicing allows to match services to optimized network instances, and it also allows for a more optimized use of those specific resources

- Allows for individual network statistics: With service specific network slices and possibly even on the level of individual enterprises, there is a possibility of collecting network statistics specific for a limited and well defined group of users of the network slice. This is not the key driver for slicing but rather a benefit that may be a useful tool

Slicing can also be used to isolate different services in an operator's network. Future networks are expected to support new use cases going beyond the basic support for voice services and mobile broadband currently supported by existing cellular network, e.g. 2G/3G/4G. Some example use cases include:

- Evolution of MB B

> Evolved communication services

> Cloud services

> Extended mobility and coverage

Mission critical Machine Type Communication

> Intelligent traffic systems

> Smart grid

> Industrial applications

Massive Machine Type Communication

> Sensors/actuators

> Capillary networks

- Media

> Efficient on-demand media delivery

> Media awareness

> Efficient support for broadcast services

These use cases are expected to have different performance requirements, e.g. bit-rates, latencies, as well as other network requirements, e.g. mobility, availability, security etc., affecting the network architecture and protocols. Supporting these use cases could also mean that new players and business relations are needed compared to existing cellular networks. For instance it is expected that future networks should address the needs of

Enterprise services

- Government services, e.g. national and/or public safety

- Verticals industries, e.g. automation, transportation

Residential users

These different users and services are also expected to put new requirements on the network. Fig. 6 shows an example of a network slicing for a case when there exists different network slices in the core network for MBB, Massive MTC and Critical MTC. In other words, the network slices may comprise separate core network instances supporting the different network slices.

Network slicing introduces the possibility that the network slices are used for different services and use cases and there is a need to enable usage of this mechanism for wireless devices in the communication network to improve the performance of the communication network. Thus, Network slicing consists of defining, realizing and operating end-to-end logical networks by means of dedicated and/or shared resources in the Core Network and/or the Radio Access Network and associated management system(s). A problem is to enable a wireless device to perform active mode mobility, i.e. handover, when being connected to multiple network slices to improve the performance of the communication network.

SUMMARY

An object of embodiments herein is to provide a mechanism for improving performance of the communication network in an efficient manner.

According to an aspect the object is achieved by a method performed by a first radio network node for handling communication for a wireless device in a communication network. The communication network comprises a first core network and a second core network connected to one or more radio access networks with the first radio network node and a second radio network node. The communication network comprises partitioned sets of functionalities wherein a first set of functionalities belongs to a first network slice, supporting the wireless device, of a first core network node in the first core network, and a second set of functionalities belongs to a second network slice, supporting the wireless device, of a second core network node in the second core network. The first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network. The first radio network node connects the wireless device to the first core network node for providing the first set of functionalities of the first network slice to the wireless device. The first radio network node further connects the wireless device to the second core network node for providing the second set of functionalities of the second network slice to the wireless device. The first radio network node decides to perform a handover of the wireless device from the first radio network node to the second radio network node in the communication network. The first radio network node sends a request, to the second radio network node, for performing the handover of the wireless device, which request comprises an indication that the wireless device is further connected to the second core network node.

According to another aspect the object is achieved by a method performed by a second radio network node for handling communication for a wireless device in a communication network. The communication network comprises a first core network and a second core network connected to one or more radio access networks with a first radio network node and the second radio network node. The communication network comprises partitioned sets of functionalities wherein a first set of functionalities belongs to a first network slice, supporting the wireless device, of a first core network node in the first core network, and a second set of functionalities belongs to a second network slice, supporting the wireless device, of a second core network node in the second core network. The first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network. The second radio network node receives a request, from the first radio network node, for performing a handover of the wireless device to the second radio network node, which request comprises an indication that the wireless device is further connected to the second core network node. The second radio network node initiates a path switch to the second radio network node for the second core network node by transmitting, to the second core network node, a second request for path switching, which second request indicates the second radio network node to perform the path switch to.

According to yet another aspect the object is achieved by providing a first radio network node for handling communication for a wireless device in a communication network. The communication network comprises a first core network and a second core network connected to one or more radio access networks with the first radio network node and a second radio network node. The communication network comprises partitioned sets of functionalities wherein a first set of functionalities belongs to a first network slice, supporting the wireless device, of a first core network node in the first core network, and a second set of functionalities belongs to a second network slice, supporting the wireless device, of a second core network node in the second core network. The first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network. The first radio network node is configured to connect the wireless device to the first core network node for providing the first set of functionalities of the first network slice to the wireless device. The first radio network node is configured to further connect the wireless device to the second core network node for providing the second set of functionalities of the second network slice to the wireless device. The first radio network node is further configured to decide to perform a handover of the wireless device from the first radio network node to the second radio network node in the communication network. The first radio network node is also configured to send a request, to the second radio network node, for performing the handover of the wireless device. The request comprises an indication that the wireless device is further connected to the second core network node.

According to yet another aspect the object is achieved by providing a second radio network node for handling communication for a wireless device in a communication network. The communication network comprises a first core network and a second core network connected to one or more radio access networks with a first radio network node and the second radio network node. The communication network comprises partitioned sets of functionalities wherein a first set of functionalities belongs to a first network slice, supporting the wireless device, of a first core network node in the first core network, and a second set of functionalities belongs to a second network slice, supporting the wireless device, of a second core network node in the second core network. The first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network. The second radio network node is configured to receive a request, from the first radio network node, for performing a handover of the wireless device to the second radio network node, which request comprises an indication that the wireless device is further connected to the second core network node. The second radio network node is also configured to initiate a path switch to the second radio network node for the second core network node by being configured to transmit, to the second core network node, a second request for path switching, which second request indicates the second radio network node to perform the path switch to.

It is furthermore provided herein a computer program comprising instructions, which, when executed on at least one processor, cause the at least one processor to carry out any of the methods above, as performed by the first radio network node, the second radio network node, or the core network node. It is additionally provided herein a computer-readable storage medium, having stored thereon a computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to any of the methods above, as performed by the first radio network node, the second radio network node, or the core network node.

Embodiments herein introduce an efficient manner of enabling sliced network structuring and usage by introducing additional signaling procedures at active mode mobility, i.e. being connected to network slices during a handover. By sending the indication that the wireless device is further connected to the second core network node enables the second radio network to initiate the path switch to the second radio network node for the second core network node. Embodiments herein thus enable the

communication for the wireless device, being connected, across RAN nodes or RANs in an efficient manner leading to an improved performance of the wireless communication network.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described in more detail in relation to the enclosed drawings, in which:

Fig. 1 is a schematic overview depicting a communication network according to prior art; Fig. 2 is a schematic overview depicting a radio access network in connection with a core network;

Fig. 3 is a schematic overview depicting a radio access network in connection with a core network;

Fig. 4 is a signalling scheme according to prior art;

Fig. 5 is a signalling scheme according to prior art;

Fig. 6 is a schematic overview depicting an example of a slicing of a core network

according to prior art;

Fig. 7 is a schematic overview depicting network slicing;

Fig. 8 is a schematic overview depicting network slicing;

Fig. 9a is a schematic overview depicting a communication network according to

embodiments herein;

Fig. 9b is a combined flowchart and signalling scheme according to embodiments herein; Fig. 10 is a schematic flowchart depicting a method performed by a first radio network node according to embodiments herein; Fig. 11 is a schematic flowchart depicting a method performed by a second radio network node according to embodiments herein;

Fig. 12 is a combined flowchart and signalling scheme according to embodiments herein; Fig. 13 is a combined flowchart and signalling scheme according to embodiments herein; Fig. 14 is a block diagram depicting a first radio network node according to embodiments herein; and

Fig. 15 is a block diagram depicting a second radio network node according to

embodiments herein. DETAILED DESCRIPTION

As part of developing embodiments herein a problem has first been identified. A management system may comprise a domain manager (DM), also referred to as the operation and support system (OSS) node managing the radio network nodes. A DM may further be managed by a network manager (NM). The radio network nodes may be interfaced by X2 and/or S1 interfaces, whereas an interface between two DMs is referred to as ltf-P2P. The management system may configure the radio network nodes, as well as receive observations associated with features in the radio network nodes. For example, DM observes and configures radio network nodes, while NM observes and configures DM, as well as the radio network nodes via DM. By means of configuration via the DM, NM and related interfaces, functions over the X2 and S1 interfaces can be carried out in a coordinated way throughout the RAN, eventually involving the Core Network, i.e. MME and S-GWs.

It is not yet specified by 3GPP if and how the LTE architecture should evolve to meet the challenges of the 5G time frame. It is assumed that there will be evolved counterparts of the S1 , X2 and Uu interfaces and that any new RAT would be integrated with the LTE radio interface at RAN level in a similar fashion as the way LTE Dual

Connectivity is defined. Embodiments herein will work for both an LTE-like architecture and a new architecture based on an evolution of the S1 interface.

Network slicing is about creating logically separated partitions of the network, addressing different business purposes. These "network slices" are logically separated to a degree that they can be regarded and managed as networks of their own.

The network slicing applies to both LTE based networks and 5G Radio Access Technology (RAT). The network slicing supports business expansion, i.e. improving the cellular operator's ability to serve other industries, e.g., by offering connectivity services with different network characteristics, such as performance, security, robustness, and complexity. One shared Radio Access Network (RAN) infrastructure, comprising one or more RANs, connects to several Evolved Packet Core (EPC) instances, e.g. one EPC instance per network slice. As the EPC functions are being virtualized, it is assumed that the operator shall instantiate a new Core Network (CN) when a new slice should be supported. This architecture is shown in Fig. 7. Slice 0 can for example be a Mobile Broadband slice and Slice 1 can for example be a Machine Type Communication network slice.

Active mode mobility in existing LTE/EPC networks, i.e. before network slicing is introduced, can be performed either using S1- or X2-based handovers. S1 based handover procedure is described in 3GPP TS 23.401 (V13.4.0). X2 based handover procedure is described in 3GPP TS 36.300 (V13.1.0).

The problem identified herein is that the current active mode mobility principles described for LTE/EPC do not handle the case when a wireless device is connected to multiple network slices provided by multiple CN nodes. This scenario is shown in Fig.8. The wireless device being connected to multiple CN nodes means that the current radio network node for the wireless device has two or more S1 associations for the wireless device towards different MMEs in the different CN instances. Fig. 8 shows the case of 2 such MMEs.

S1 handover could be used towards one of the CN instances but the other CN instances would not be aware of the performed handover. In a similar way, X2 handover could be performed between radio network nodes in the RAN followed by a Path Switch to one of the CN instances as specified in 3GPP. This would also result in that the other CN instances are not aware of the performed handover. Therefore embodiments herein are provided to solve the problem to update all the CN instances, CN nodes, for a wireless device at active mode mobility, i.e. either S1-based or X2-based handover. Embodiments herein cover e.g. the case when the multiple network slices where the wireless device is connected to are provided by multiple core network nodes and connectivity to each core network node is provided by separate S1 associations.

Embodiments herein relate to communication networks in general. Fig. 9a is a schematic overview depicting a communication network 1. The communication network 1 comprises one or more RANs e.g. a first RAN (RAN1), connected to a plurality of CNs, exemplified as a first CN (CN 1), a second CN (CN2) and a third CN (CN3), all packet switched core networks. The communication network 1 may use a number of different technologies, such as Wi-Fi, Long Term Evolution (LTE), LTE-Advanced, 5G, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/Enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide

Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. Embodiments herein relate to recent technology trends that are of particular interest in a 5G context, however, embodiments are

applicable also in further development of the existing communication systems such as e.g. 3G and LTE.

In the communication network 1 , wireless devices e.g. a wireless device 10 such as a mobile station, a non-access point (non-AP) STA, a STA, a user equipment and/or a wireless terminal, are connected via the one or more RANs, to the CNs. It should be understood by those skilled in the art that "wireless device" is a non-limiting term which means any terminal, wireless communication terminal, user equipment, Machine Type Communication (MTC) device, Device to Device (D2D) terminal, or node e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or any device communicating within a cell or service area.

The communication network 1 comprises a first radio network node 12 providing radio coverage over a geographical area, a first service area 11 , of a first radio access technology (RAT), such as LTE, UMTS, Wi-Fi or similar. The first radio network node 12 may be a radio access network node such as radio network controller or an access point such as a wireless local area network (WLAN) access point or an Access Point Station (AP STA), an access controller, a base station, e.g. a radio base station such as a NodeB, an evolved Node B (eNB, eNodeB), a base transceiver station, Access Point Base Station, base station router, a transmission arrangement of a radio base station, a stand-alone access point or any other network unit capable of serving a wireless device within the service area served by the first radio network node 12 depending e.g. on the first radio access technology and terminology used. The first core network is virtually network sliced into one or more network slices, each network slice or core network slice supports one or more types of wireless devices and/or one or more types of services i.e. each network slice supports a different set of functionalities. Network slicing introduces the possibility that the network slices are used for different services and use cases and these services and use cases may introduce differences in the functionality supported in the different network slices. Each network slice may comprise one or more network nodes or elements of network nodes providing the services/functionalities for the respective network slice. Each network slice may comprise a network node such as a RAN node or a core network node e.g. Radio Software Defined Networking (SDN) nodes, MMEs, S-GWs, Serving GPRS Support Nodes (SGSN), or corresponding nodes in e.g. a 5G network or similar. The GPRS meaning General Packet Radio Services. For example, a first network slice for e.g. MBB devices may comprise a first core network node 13 of the CN1. A second network slice for e.g. a certain enterprise may comprise a second core network node 14 of the CN2. A third network slice for e.g. a certain operator, may comprise a third core network node 15 of the CN3. Each network slice supports a set of functionalities out of a total set of functionalities in the communication network. E.g. the first core network node 13 supports a first set of functionalities out of the total set of functionalities in the communication network 1. The first set of functionalities is separated from a different set of functionalities out of the total set of functionalities in the communication network 1. E.g. the first set of functionalities being associated with MBB devices is separated or logically separated, e.g. using separated data storage or processing resources, from a second set of functionalities of the second network slice and a third set of functionalities of the third network slice.

The first set of functionalities may use one or more resources in a core or RAN network of the communication network, which one or more resources are separated from other resources used by a different set of functionalities, i.e. different network slices, out of the total set of functionalities in the communication network 1. The resources may then be dedicated or virtually dedicated for each set of functionalities or network slice. Thus, the core network node may be separated from other core network nodes supporting a second set of functionalities out of the total set of functionalities in the communication network. Separated meaning herein physically separated wherein the core network nodes may be executed on different hardware platforms and therefore using different resources of the hardware, and/or logically separated wherein the core network nodes may be executed on a same hardware platform and use different resources such as memory parts or resources of processor capacity but may also use some same resources of the hardware e.g. a single physical core network node may be partitioned into multiple virtual core network nodes.

Hence, the first core network node 13 supports the first set of functionalities out of the total set of functionalities in the first core network of the communication network, which first set of functionalities belongs to the first network slice of the first core network, and is separated from another set of functionalities out of the total set of functionalities in the first network. The second and third sets of functionalities out of a total set of functionalities in the communication network may be different or the same or similar as ones supported by the first network slice. Furthermore, the communication network 1 comprises a second radio network node 16 providing radio coverage over a geographical area, a second service area 17, of a second radio access technology (RAT), such as LTE, UMTS, Wi-Fi or similar. The second radio network node 16 has its own radio resource management (RRM) for the second service area 17. The second radio network node 16 may be a radio access network node such as radio network controller or an access point such as a WLAN access point or an Access Point Station (AP STA), an access controller, a base station, e.g. a radio base station such as a NodeB, an evolved Node B (eNB, eNodeB), a base transceiver station, Access Point Base Station, base station router, a transmission arrangement of a radio base station, a stand-alone access point or any other network unit capable of serving a wireless device within the service area served by the second radio network node 16 depending e.g. on the second radio access technology and terminology used. The second radio network node 16 is comprised in the same or different RAN as the first radio network node 12 and the first and second RAT may be the same or different RATs.

The first radio network node 12 is connected to the second radio network node 16, over e.g. an X2 connection/s, S1 connection/s or a combination thereof or similar, and bearer traffic addressed to and from the wireless device 10 may be delivered by the first and second radio network nodes.

According to embodiments herein the wireless device 10 moves to the second radio network node 16 from the first radio network node 12, or actually moves into the second service area 17, which might be the same, overlapping or different than the first service area 11. The wireless device 10 is connected, at a control plane level and/or user plane level, to the first core network node 13 of the first network slice, the second core network node 14 of the second network slice and the third core network node 15 of the third network slice. The first radio network node 16 decides e.g. based on signalling strength or quality to perform a handover (HO) of the wireless device 10 from the first radio network node 12 to the second radio network node 16. The first radio network node 12 sends a request, e.g. HO request, to the second radio network node 16, for performing the handover of the wireless device 12. The request comprises an indication that the wireless device is further connected to the second core network node 14 and the third core network node 15, the indication may further indicate that the wireless device 10 is connected to the first core network node 13. E.g. the request may comprise a list of connections or active connections for the wireless device 10 and corresponding core network nodes. The second radio network node 16, being a target radio network node, initiates one or more path switches to the second radio network node 16 for the second core network node 14 and third core network node 15 by transmitting, to the second core network node 14 and the third core network node 15, a second and third request for path switching. Each request indicates where to perform the path switch i.e. each request indicates a path switch to the second radio network node 16. Embodiments herein cover both X2 handovers as well as S1 handovers. For example, when S1 -based handover is triggered e.g. via the first core network node 13 serving the first network slice for the wireless device 10, a Path Switch procedure, that is normally only used for X2 handover, is triggered towards all other core network nodes serving network slices for the wireless device i.e. the second core network node 14 and the third core network node 15. In a similar way, multiple Path Switch procedures are triggered after a successful X2 handover towards all core network nodes serving network slices for the wireless device 10 i.e. the first core network node 13, the second core network node 14 and the third core network node 15. Finally, embodiments herein also allow the possibility to trigger multiple S1- based handovers for some of the core network nodes, e.g. the first and third core network nodes, serving network slices for the wireless device 10 followed by Path Switch procedures for the rest of the core network nodes, e.g. the second core network node 14, serving network slices for the wireless device 10. The indication such as the list of active connections, is comprised in the request from the wireless device, e.g. in the handover preparation signaling, towards the second radio network node 16. Embodiments herein thus enable the communication for the wireless device across RAN nodes or RANs leading to an improved performance of the wireless communication network.

Fig. 9b is a combined flowchart and signalling scheme according to embodiments herein for handling communication for the wireless device 10. The radio network nodes may be connected via an X2-interface. The core network side implements a plurality of different core network nodes supporting different network slices. Each core network node may be a single MME, a pool of MMEs, and/or a single user plane gateway (GW), and additional nodes are likely to exist both for the wireless device 10 and other wireless devices. Both radio network nodes are connected to the different core network nodes using e.g. S1-MME interfaces and/or also via S1-U interfaces to the GWs.

Action 901. The wireless device 10 connects to the first and second core network node for providing the respective set of functionalities to the wireless device 10. The wireless device 10 connects to the core network nodes, i.e. performs attach and connects over control plane connections and/or user plane connections. Action 902. The first radio network node 12 decides or determines to perform a handover of the wireless device 10 to the second radio network node 16. This may be based in signalling measurements of signal strength or quality. Hence, the wireless device 10 is initially connected to the first radio network node 12 and is to be handed over to the second radio network node 16.

Action 903. The first radio network node 12 transmits a request such as a HO request to the second radio network node 16. The first radio network node 12 may transmit the request directly to the second radio network node 16 e.g. in an X2 handover process. The first radio network node 12 may alternatively transmit the request to the second radio network node 16 via the first core network node 13, shown as a dashed line. According to embodiments herein the request comprises an indication of active

connections, e.g. a connection list also referred to as an active CN instances list, an active session list, an active connections list.

Action 904. The first radio network node 12 may then receive a confirmation, such as a HO acknowledgement (ACK), from the second radio network node 16. The first radio network node 12 may receive the confirmation directly from the second radio network node 16 e.g. in an X2 handover process. The first radio network node 12 may alternatively receive the request from the second radio network node 16 via the first core network node 13, shown as a dashed line.

Action 905. The second radio network node 16 and the wireless device 10 may then establish a Radio Resource Control connection to the wireless device 10.

Action 906. The second radio network node 16 then uses the received connection list to determine which core network nodes to inform about the handover.

Action 907. The second radio network node 16 initiates a path switch by transmitting a second request e.g. a path switch request to the second core network node 14 to inform the second core network node 14 to perform a path switch from the first radio network node 12 to the second radio network node 16. In an X2 handover also a path switch for the first core network node 13 is initiated (dashed line).

Action 908. The wireless device 10 is connected to the first core network node 13 and the second core network node 14 i.e. the first network slice and the second network slice via the second radio network node 16.

The method actions performed by the first radio network node 12 for handling the communication for the wireless device 10 in the communication network 1 according to some embodiments will now be described with reference to a flowchart depicted in Fig. 10. The communication network 1 comprises the first core network and the second core network connected to one radio access networks with the first radio network node 12 and a second radio network node 16 or to different RANs with first radio network node 12 and the second radio network node 16. The first and second core networks may be packet 5 switched core networks. The communication network 1 comprises partitioned sets of functionalities wherein the first set of functionalities belongs to the first network slice supporting the wireless device 10 of the first core network node 13 in the first core network, and the second set of functionalities belongs to the second network slice supporting the wireless device 10 of the second core network node 14 in the second core

10 network, and which first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network 1. The actions do not have to be taken in the order stated below, but may be taken in any suitable order. Actions performed in some embodiments are marked with dashed boxes. The first radio network node 12 may be comprised in a first radio access

15 network and the second radio network node16 may be comprised in a second radio

access network, or the first and second network nodes may be comprised in a same radio access network.

Action 1001. The first radio network node 12 connects the wireless device 10 to the first core network node 13 for providing the first set of functionalities of the first 20 network slice to the wireless device 10.

Action 1002. The first radio network node 12 further connects the wireless device 10 to the second core network node 14 for providing the second set of functionalities of the second network slice to the wireless device 10.

Action 1003. The first radio network node 12 decides to perform the handover of 25 the wireless device 10 from the first radio network node 12 to the second radio network node 16 in the communication network 1.

Action 1004. The first radio network node 12 sends the request, to the second radio network node 16, for performing the handover of the wireless device 12, which request comprises the indication that the wireless device 10 is further connected to the 30 second core network node 14. The request may comprises a list of active connections for the wireless device 10 to respective core network nodes, which list comprises the indication, e.g. a connection list, an active connections list. A list for connections which the wireless device 10 is in "RRC_CONNECTED/ECM_CONNECTED" state or a list of connections defined by GUMMEI, MME UE S1AP ID and context of the wireless device 35 10. The indication may comprise the identity of the second core network node 14, e.g. MMECode of the GUMMEI, the identity related to the wireless device 10 in the second core network node 14, e.g. MME UE S1AP ID, and context of the wireless device, e.g.. E- RAB. The handover may be an X2 handover and the request may then be sent to the second radio network node 16 directly over an X2 interface. The request may then further comprise another indication that the wireless device is connected to the first core network node 13. The handover may be a S1 handover and the request may then be sent to the second radio network node 16 via the first core network node 13 over an S1 association.

The method actions performed by the second radio network node 16 for handling the communication for the wireless device 10 in the communication network according to some embodiments will now be described with reference to a flowchart depicted in Fig. 11. The communication network 1 comprises the first core network and the second core network connected to one or more radio access networks with the first radio network node 12 and the second radio network node 16. The communication network 1 comprises partitioned sets of functionalities wherein a first set of functionalities belongs to a first network slice supporting the wireless device 10 of the first core network node 13 in the first core network, and the second set of functionalities belongs to the second network slice supporting the wireless device 10 of the second core network node 14 in the second core network. The first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network 1. The actions do not have to be taken in the order stated below, but may be taken in any suitable order. Actions performed in some embodiments are marked with dashed boxes.

Action 1101. The second radio network node 16 receives the request, from the first radio network node 12, for performing the handover of the wireless device 10 to the second radio network node 16, which request comprises the indication that the wireless device 10 is further connected to the second core network node 14. In the case of X2 handover the indication or another indication in the request may also comprise the identity of the first core network node 13. The indication may comprise the list of active

connections for the wireless device to respective core network nodes, which list comprises the indication. The indication may comprise the identity of the second core network node 14, e.g. MMECode of the GUMMEI, the identity related to the wireless device 10 in the second core network node 14, e.g. MME UE S1AP ID, and context of the wireless device, e.g. E-RAB. Action 1102. The second radio network node 16 may store the indication. E.g. the second radio network node 16 may store the list for later use.

Action 1103. The second radio network node 16 initiates the path switch to the second radio network node 16 for the second core network node 14 by transmitting, to the second core network node 14, the second request, e.g. the path switch request, for path switching. The second request indicates the second radio network node 16 to perform the path switch to.

In some embodiments when the handover is an X2 handover, the request may further comprise another indication. The other indication may indication that the wireless device is connected to the first core network node 13, e.g. be a second active connection in the list. The second radio network node 16 may then trigger the initiation of the path switch after a successful X2 handover, and may further initiate an initial path switch to the second radio network node 16 for the first core network node 13 by transmitting, to the first core network node 13, an initial request for path switching, which initial request indicates the second radio network node 16 to perform the path switch to, see Fig. 13.

In some embodiments when the handover is an S1 handover and the indication is received via the first core network node 13, the initiation of the path switch is triggered after successful S1 Handover, see Fig. 12. Fig. 12 is a combined flowchart and signalling scheme according to embodiments herein for handling communication for the wireless device 10 when the handover is an S1 handover.

Signaling flow for the case of single S1 -handover with multiple Path Switches is shown in Fig. 12.

Action 1201. The wireless device 10 (UE) is initially connected to all 3 CN instances, three CN nodes, via source eNB, i.e. the first radio network node 12.

Action 1202. The first radio network node 12 may decide to perform S1-HO for the wireless device 10.

Action 1203. The first radio network node 12 transmits a S1AP HANDOVER REQUIRED message to the first core network node 13. The S1AP HANDOVER

REQUIRED message comprises an active connections list with GUMMEI and UE Context information. The basic principle is that the source eNB, the first radio network node 12, triggers S1-based handover (action 1203). The new information included in the S1AP HANDOVER REQUIRED message is called Active connections list and provides information to the target eNB, the second radio network node 16, about the CN instances for which the Path Switch procedure should be triggered after successful S1 Handover.

The information included in the Active connections list consists of the following for each CN instance:

- GUMMEI of the MME.

- MME UE S1AP ID allocated at the MME.

Context such as Έ-RABs To Be Setup List' as used in the standards today consisting of for example E-RAB ID, E-RAB Level QoS Parameters, DL Forwarding and UL GTP Tunnel Endpoint

The information included in the Active connections list may also contain for each

CN instance such as Handover Restriction List and Subscriber Profile ID (SPID) for RAT/Frequency priority if these have been previously received from the different CN instances (and there is a need to forward these to the target eNB). In addition, other information may also be included in the message.

Action 1204. The first core network node 13 transmits an S1AP HANDOVER

REQUEST message to the second radio network node 16. Thus, the Active connections list is forwarded ( action 1204) to the target eNB using existing S1 AP messages and is there stored (step 1205).

Action 1205. The second radio network node 16 stores the active connections list. Action 1206. The second radio network node 16 transmits an S1AP HANDOVER

REQUEST ACKNOWLEDGE message to the first core network node 13.

Action 1207. The first core network node 13 transmits an S1AP HANDOVER COMMAND message to the first radio network node 12.

Action 1208. The first radio network node 12 transmits a RRC Connection

Reconfiguration message to the wireless device 10.

Action 1209. The wireless device 10 may transmit a RRC Connection

Reconfiguration Complete message to the second radio network node 16.

Action 1210. The second radio network node 16 may transmit a S1AP

HANDOVER NOTIFY message to the first core network node 13 confirming the handover.

Action 1211. The second radio network node 16 uses the stored active

connections list. Once the S1-based handover is successfully performed the target eNB uses the stored Active connections list to trigger Path Switch procedures towards the second core network node 14, MME2, and the third core network node 15, MME3 (in CN instances #2 and #3 respectively). Fig. 12 shows the case when the Path Switch procedures are triggered first after a successful S1 handover. In some scenarios it may be possible to trigger these already after step 1204.

Action 1212. The second radio network node 16 transmits a S1AP PATH

SWITCH REQUEST to the second core network node 14 and receives a S1AP PATH SWITCH ACKNOWLEDGE (... ) when path switch is performed.

Action 1213. The second radio network node 16 transmits a S1AP PATH

SWITCH REQUEST to the third core network node 15 and receives a S1AP PATH SWITCH ACKNOWLEDGE (... ) when path switch is performed.

Action 1214. The wireless device 10 (UE) is then initially connected to all 3 CN instances via target eNB, i.e. the second radio network node 16.

It is also possible to trigger multiple S1 handovers and one or multiple Path Switches. One example case is that the source eNB would trigger S1-based handovers towards MME1 (in CN instance #1) and MME2 (in CN instance #2) and after a successful S1 handover, a Path Switch would be triggered towards MME3 (in CN instance #3).

The possible benefit with this kind of solution is that the S1-based handover allows also the possibility to change MME in the CN, i.e within a CN instance, and this is not possible at X2-based handover, i.e. at Path Switch.

Multiple S1 handovers raise some issues also as this would mean that the target eNB receives multiple handover preparations for the same wireless device 10 and same handover. This means that the target eNB would really only need to build a single "RRC Connection Reconfiguration" message and return this as a response to only one of the handover preparations. For this to be possible, the source eNB would need to include some common identifier that is transferred transparently via the CN instances to the target eNB. This would enable that the target eNB can associate the different handover preparations. In another variant, the target eNB builds a single "RRC Connection

Reconfiguration" message for each handover preparation as normally and the source eNB ensures that only a single "RRC Connection Reconfiguration" message is sent to the wireless device 10.

The Active connections list can be handled in different ways in this type of solution. The list may only contain information for the CN instances for which the Path Switch needs to be triggered (i.e. MME3 in CN instance #3 in the above example). The list may be included in either one of the S1-based handover preparations as shown in Fig. 12 or in multiple such handover preparations. Fig. 13 is a combined flowchart and signalling scheme according to embodiments herein for 10 handling communication for the wireless device when the handover is an X2 handover.

Signaling flow for the case of X2-handover with multiple Path Switches is shown in Fig. 13. Action 1301. The wireless device 10 (UE) is initially connected to all 3 CN instances, three CN nodes, via source eNB, i.e. the first radio network node 12.

Action 1302. The first radio network node 12 may decide to perform X2-HO for the wireless device 10.

Action 1303. The first radio network node 12 transmits a S1AP HANDOVER REQUIRED message to the first core network node 13. The S1AP HANDOVER

REQUIRED message comprises an active connections list with GUMMEI and UE Context information. The basic principle is that the source eNB, the first radio network node 12, triggers X2-based handover (action 1303). The new information included in the X2AP HANDOVER REQUEST message is called Active connections list and provides information to the second radio network node 16 about all CN instances for which the Path Switch procedure should be triggered after successful X2 Handover.

The information included in the Active connections list may comprise the following for each CN instance:

- GUMMEI of the MME.

- MME UE S1AP ID allocated at the MME.

Context of the wireless device 10 e.g. Έ-RABs To Be Setup List' as used in the standards today consisting of for example E-RAB ID, E-RAB Level QoS Parameters, DL Forwarding and UL GTP Tunnel Endpoint

The information included in the Active connections list may also contain for each CN instance such as Handover Restriction List and Subscriber Profile ID (SPID) for RAT/Frequency priority if these have been previously received from the different CN instances, and there is a need to forward these to the target eNB. In addition, other information may also be included in the message.

The X2AP HANDOVER REQUEST already today contains all the information needed to perform Path Switch towards a single CN instance. Therefore it may be preferred to keep the current formatting in the X2AP HANDOVER REQUEST message and include information for one CN instance in the existing information elements and then include rest of the CN instances in the Active connections list i.e. information for 1^st CN node is included in the existing information elements and 2^nd and 3^rd CN node are included in the "Active connections list". Action 1304. The second radio network node 16 stores the active connections list.

Action 1305. The second radio network node 16 transmits an X2AP HANDOVER REQUEST ACKNOWLEDGE message to the first radio network node 12.

Action 1306. The first radio network node 12 transmits a RRC Connection Reconfiguration message to the wireless device 10.

Action 1307. The wireless device 10 may transmit a RRC Connection

Reconfiguration Complete message to the second radio network node 16.

Action 1308. The second radio network node 16 uses the stored active

connections list. Thus, the Active connections list is sent (action 1303) to the target eNB using existing X2AP message (i.e. X2AP HANDOVER REQUEST) and stored there (action 1304). Once the X2-based handover is successfully performed the second radio network node 16 uses the stored Active connections list to trigger Path Switch procedures towards MME1 , MME2 and MME3 (in CN instances #1 , #2 and #3

respectively). Fig. 13 shows the case when the Path Switch procedures are triggered first after a successful X2 handover. In some scenarios it may be possible to trigger these already after step 1303.

Action 1309. The second radio network node 16 transmits a S1AP PATH

SWITCH REQUEST to the first core network node 13 and receives a S1AP PATH

SWITCH ACKNOWLEDGE (... ) when path switch is performed.

Action 1310. The second radio network node 16 transmits a S1AP PATH

Action 1311. The second radio network node 16 transmits a S1AP PATH

Action 1312. The wireless device 10 (UE) is then initially connected to all 3 CN instances via target eNB, i.e. the second radio network node 16.

Fig. 14 is a block diagram depicting the first radio network node 12 according to embodiments herein for handling communication for the wireless device 10 in the communication network 1. The communication network 1 comprises the first core network and the second core network connected to one or more radio access networks with the first radio network node 12 and the second radio network node 16. The communication network 1 comprises partitioned sets of functionalities wherein the first set of

functionalities belongs to the first network slice, supporting the wireless device 10, of a first core network node 13 in the first core network, and the second set of functionalities belongs to the second network slice, supporting the wireless device 10, of the second core network node 14 in the second core network. The first and second sets of functionalities are separated from one another and other sets of functionalities out of the total set of functionalities in the communication network 1.

The first radio network node 16 may comprise a processing unit 1401 , one or more processors, configured to perform the methods herein. The first radio network node 12 may comprise a connecting module 1402. The first radio network node 12, the processing unit 1401 and/or the connecting module 1402 may be configured to connect the wireless device 10 to the first core network node 13 for providing the first set of functionalities of the first network slice to the wireless device 10. The first radio network node 12, the processing unit 1401 and/or the connecting module 1402 may be configured to further connect the wireless device 10 to the second core network node 14 for providing the second set of functionalities of the second network slice to the wireless device.

The first radio network node 12 may comprise a deciding module 1403. The first radio network node 12, the processing unit 1401 and/or the deciding module 1403 may be configured to decide to perform a handover of the wireless device 10 from the first radio network node 12 to the second radio network node 16 in the communication network 1.

The first radio network node 12 may comprise a sending module 1404. The first radio network node 12, the processing unit 1401 and/or the sending module 1404 may be configured to send the request, to the second radio network node 16, for performing the handover of the wireless device 12. The request comprises an indication that the wireless device 10 is further connected to the second core network node 14. The request may comprise a list of active connections for the wireless device 10 to respective core network nodes, which list comprises the indication. The indication may comprises the identity of the second core network node 14, the identity related to the wireless device 10 in the second core network node 14 and the context of the wireless device 10.

The handover may be an X2 handover and the first radio network node 12, the processing unit 1401 and/or the sending module 1404 may then be configured to send the request to the second radio network node 16 directly over an X2 interface, and the request further comprises another indication that the wireless device 10 is connected to the first core network node 13. The handover may be an X2 handover and the first radio network node 12, the processing unit 1401 and/or the sending module 1404 may then be configured to send the request to the second radio network node 16 via the first core network node 13 over an S1 association. The first radio network node 12 further comprises a memory 1405. The memory comprises one or more units to be used to store data on, such as sets of functionalities, indications, list of active connections, identities of network slices, context, identities, signaling measurements, applications to perform the methods disclosed herein when being executed, and/or similar.

The methods according to the embodiments described herein for the first radio network node 12 are respectively implemented by means of e.g. a computer program 1406 or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the first radio network node 12. The computer program 1406 may be stored on a computer-readable storage medium 1407, e.g. a disc or similar. The computer-readable storage medium 1407, having stored thereon the computer program, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the first radio network node 12. In some embodiments, the computer-readable storage medium may be a non-transitory computer-readable storage medium.

Fig. 15 is a block diagram depicting the second radio network node 16 according to embodiments herein for handling communication for the wireless device 10 in the communication network 1. The communication network 1 comprises the first core network and the second core network connected to one or more radio access networks with the first radio network node 12 and the second radio network node 16. The communication network 1 comprises partitioned sets of functionalities wherein the first set of

functionalities belongs to the first network slice supporting the wireless device 10 of the first core network node 13 in the first core network, and the second set of functionalities belongs to the second network slice supporting the wireless device 10 of the second core network node 14 in the second core network. The first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network 1.

The second radio network node 16 may comprise a processing unit 1501 , one or more processors, configured to perform the methods herein. The second radio network node 16 may comprise a receiving module 1502. The second radio network node 16, the processing unit 1501 , and/or the receiving module 1502 may be configured to receive the request, from the first radio network node 12, for performing the handover of the wireless device 10 to the second radio network node 16. The request comprises the indication that the wireless device 10 is further connected to the second core network node 14. The request may comprise a list of active connections for the wireless device to respective core network nodes, which list comprises the indication.

The second radio network node 16 may comprise an initiating module 1503. The second radio network node 16, the processing unit 1501 , and/or the initiating module 1503 may be configured to initiate the path switch to the second radio network node 16 for the second core network node 14 by being configured to transmit, to the second core network node 14, the second request for path switching. The second request indicates the second radio network node 16 to perform the path switch to. The indication may comprise the identity of the second core network node 14, the identity related to the wireless device 10 in the second core network node 14, and the context of the wireless device 10.

The second radio network node 16 may comprise a storing module 1504. The second radio network node 16, the processing unit 1501 , and/or the storing module 1504 may be configured to store the indication.

The handover may be an X2 handover and the request may then further comprise another indication that the wireless device 10 is connected to the first core network node 13. The second radio network node 16, the processing unit 1501 , and/or the initiating module 1503 may be configured to initiate the path switch after successful X2 Handover and may further be configured to initiate the initial path switch to the second radio network node 16 for the first core network node 13 by being configured to transmit, to the first core network node 13, the initial request for path switching. The initial request indicates the second radio network node 16 to perform the path switch to.

The handover may be an S1 handover and the second radio network node 16, the processing unit 1501 , and/or the receiving module 1502 may be configured to receive the indication via the first core network node 13 and the second radio network node 16, the processing unit 1501 , and/or the initiating module 1503 may be configured to initiate the path switch after successful S1 Handover.

The second radio network node 16 further comprises a memory 1505. The memory comprises one or more units to be used to store data on, such as sets of functionalities, indications, list of active connections, identities of network slices, context, identities, signaling measurements, applications to perform the methods disclosed herein when being executed, and/or similar.

The methods according to the embodiments described herein for the second radio network node 16 are respectively implemented by means of e.g. a computer program 1506 or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the second radio network node 16. The computer program 1506 may be stored on a computer-readable storage medium 5 1507, e.g. a disc or similar. The computer-readable storage medium 1507, having stored thereon the computer program, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the second radio network node 16. In some embodiments, the computer-readable storage medium may be a non-transitory computer-readable storage0 medium.

Embodiments herein relate to a network with network slices i.e. core network with partitioned sets of functionalities where the first core network node 13 supports the first set of functionalities and the second core network node 14 supports the second set of functionalities out of the total set of functionalities in the core networks of the

5 communication network. The first set of functionalities belongs to the first network slice of the core network and the second set belongs to the second network slice, and are separated from another set of functionalities out of the total set of functionalities in the core networks.

As will be readily understood by those familiar with communications design, that0 functions means or modules may be implemented using digital logic and/or one or

more microcontrollers, microprocessors, or other digital hardware. In some

embodiments, several or all of the various functions may be implemented together, such as in a single application-specific integrated circuit (ASIC), or in two or more separate devices with appropriate hardware and/or software interfaces between them.5 Several of the functions may be implemented on a processor shared with other

functional components of a radio network node, for example.

Alternatively, several of the functional elements of the processing means discussed may be provided through the use of dedicated hardware, while others are provided with hardware for executing software, in association with the appropriate

0 software or firmware. Thus, the term "processor" or "controller" as used herein does not exclusively refer to hardware capable of executing software and may implicitly include, without limitation, digital signal processor (DSP) hardware, read-only memory (ROM) for storing software, random-access memory for storing software and/or

program or application data, and non-volatile memory. Other hardware, conventional and/or custom, may also be included. Designers of radio network nodes will appreciate the cost, performance, and maintenance trade-offs inherent in these design choices.

It will be appreciated that the foregoing description and the accompanying drawings represent non-limiting examples of the methods and apparatus taught herein. As such, the apparatus and techniques taught herein are not limited by the foregoing description and accompanying drawings. Instead, the embodiments herein are limited only by the following claims and their legal equivalents.

Claims

A method performed by a first radio network node (12) for handling communication for a wireless device (10) in a communication network (1), which communication network (1) comprises a first core network and a second core network connected to one or more radio access networks with the first radio network node (12) and a second radio network node (16), wherein the communication network (1) comprises partitioned sets of functionalities wherein a first set of functionalities belongs to a first network slice, supporting the wireless device (10), of a first core network node (13) in the first core network, and a second set of functionalities belongs to a second network slice, supporting the wireless device (10), of a second core network node (14) in the second core network, and which first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network (1); the method comprising:

connecting (1001) the wireless device (10) to the first core network node (13) for providing the first set of functionalities of the first network slice to the wireless device (10);

further connecting (1002) the wireless device (10) to the second core network node (14) for providing the second set of functionalities of the second network slice to the wireless device;

deciding (1003) to perform a handover of the wireless device (10) from the first radio network node (12) to the second radio network node (16) in the communication network (1); and

sending (1004) a request, to the second radio network node (16), for performing the handover of the wireless device (12), which request comprises an indication that the wireless device (10) is further connected to the second core network node (14).

A method according to claim 1 , wherein the request comprises a list of active connections for the wireless device to respective core network nodes, which list comprises the indication.

3. A method according to any of the claims 1-2 wherein the indication comprises an identity of the second core network node (14), an identity related to the wireless device in the second core network node and context of the wireless device. A method according to any of the claims 1-3, wherein the handover is an X2 handover and the request is sent to the second radio network node (16) directly over an X2 interface and the request further comprises another indication that the wireless device is connected to the first core network node (13).

A method according to any of the claims 1-3, wherein the handover is an S1 handover and the request is sent to the second radio network node (16) via the first core network node (13) over an S1 association.

A method performed by a second radio network node (16) for handling

communication for a wireless device (10) in a communication network (1), which communication network (1) comprises a first core network and a second core network connected to one or more radio access networks with a first radio network node (12) and the second radio network node (16), wherein the communication network (1) comprises partitioned sets of functionalities wherein a first set of functionalities belongs to a first network slice, supporting the wireless device (10), of a first core network node (13) in the first core network, and a second set of functionalities belongs to a second network slice, supporting the wireless device (10), of a second core network node (14) in the second core network, and which first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network (1); the method comprising:

receiving (1101) a request, from the first radio network node (12), for performing a handover of the wireless device to the second radio network node (16), which request comprises an indication that the wireless device is further connected to the second core network node (14); and

initiating (1103) a path switch to the second radio network node (16) for the second core network node (14) by transmitting, to the second core network node (14), a second request for path switching, which second request indicates the second radio network node (16) to perform the path switch to.

7. A method according to claim 6, further comprising

storing (1 102) the indication.

8. A method according to any of the claims 6-7, wherein the request comprises a list of active connections for the wireless device to respective core network nodes, which list comprises the indication.

A method according to any of the claims 6-8, wherein the indication comprises an identity of the second core network node (14), an identity related to the wireless device in the second core network node and context of the wireless device (10).

10. A method according to any of the claims 6-9, wherein the handover is an X2

handover and the request further comprises another indication that the wireless device is connected to the first core network node (13), and wherein the initiating (1 103) is triggered after successful X2 Handover and further comprises initiating an initial path switch to the second radio network node (16) for the first core network node (13) by transmitting, to the first core network node (13), an initial request for path switching, which initial request indicates the second radio network node (16) to perform the path switch to.

1 1. A method according to any of the claims 6-9, wherein the handover is an S1

handover and wherein the indication is received via the first core network node (13) and the initiating is triggered after successful S1 Handover.

12. A first radio network node (12) for handling communication for a wireless device (10) in a communication network (1), which communication network (1) comprises a first core network and a second core network connected to one or more radio access networks with the first radio network node (12) and a second radio network node (16), wherein the communication network (1) comprises partitioned sets of functionalities wherein a first set of functionalities belongs to a first network slice, supporting the wireless device (10), of a first core network node (13) in the first core network, and a second set of functionalities belongs to a second network slice, supporting the wireless device (10), of a second core network node (14) in the second core network, and which first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network (1); the first radio network node (12) being configured to: connect the wireless device (10) to the first core network node (13) for providing the first set of functionalities of the first network slice to the wireless device (10);

further connect the wireless device (10) to the second core network node (14) for providing the second set of functionalities of the second network slice to the wireless device;

decide to perform a handover of the wireless device (10) from the first radio network node (12) to the second radio network node (16) in the communication network (1); and to

send a request, to the second radio network node (16), for performing the handover of the wireless device (12), which request comprises an indication that the wireless device (10) is further connected to the second core network node (14).

13. A first radio network node (12) according to claim 12, wherein the request

comprises a list of active connections for the wireless device to respective core network nodes, which list comprises the indication.

14. A first radio network node (12) according to any of the claims 12-13 wherein the indication comprises an identity of the second core network node (14), an identity related to the wireless device (10) in the second core network node (14) and context of the wireless device (10).

15. A first radio network node (12) according to any of the claims 12-14, wherein the handover is an X2 handover and first radio network node (12) is configured to send the request to the second radio network node (16) directly over an X2 interface, and the request further comprises another indication that the wireless device is connected to the first core network node (13).

16. A first radio network node (12) according to any of the claims 12-15, wherein the handover is an S1 handover and the first radio network node (12) is configured to send the request to the second radio network node (16) via the first core network node (13) over an S1 association.

17. A second radio network node (16) for handling communication for a wireless

device (10) in a communication network (1), which communication network (1) comprises a first core network and a second core network connected to one or more radio access networks with a first radio network node (12) and the second radio network node (16), wherein the communication network (1) comprises partitioned sets of functionalities wherein a first set of functionalities belongs to a first network slice, supporting the wireless device (10), of a first core network node (13) in the first core network, and a second set of functionalities belongs to a second network slice, supporting the wireless device (10), of a second core network node (14) in the second core network, and which first and second sets of functionalities are separated from one another and other sets of functionalities out of a total set of functionalities in the communication network (1); the second radio network node (16) is configured to:

receive a request, from the first radio network node (12), for performing a handover of the wireless device (10) to the second radio network node (16), which request comprises an indication that the wireless device is further connected to the second core network node (14); and to

initiate a path switch to the second radio network node (16) for the second core network node (14) by being configured to transmit, to the second core network node (14), a second request for path switching, which second request indicates the second radio network node (16) to perform the path switch to.

18. A second radio network node (16) according to claim 17, further being configured to store the indication.

19. A second radio network node (16) according to any of the claims 17-18, wherein the request comprises a list of active connections for the wireless device to respective core network nodes, which list comprises the indication.

20. A second radio network node (16) according to any of the claims 17-19, wherein the indication comprises an identity of the second core network node (14), an identity related to the wireless device in the second core network node (14), and context of the wireless device (10).

21. A second radio network node (16) according to any of the claims 17-20, wherein the handover is an X2 handover and the request further comprises another indication that the wireless device (10) is connected to the first core network node (13), and wherein the second radio network node (16) is configured to initiate the path switch after successful X2 Handover and further configured to initiate an initial path switch to the second radio network node (16) for the first core network node (13) by being configured to transmit, to the first core network node (13), an initial request for path switching, which initial request indicates the second radio network node (16) to perform the path switch to.

22. A second radio network node (16) according to any of the claims 17-20, wherein the handover is an S1 handover and the second radio network node (16) is configured to receive the indication via the first core network node (13) and configured to initiate the path switch after successful S1 Handover.

23. A computer program comprising instructions, which, when executed on at least one processor, cause the at least one processor to carry out any of the methods according to any of the claims 1-1 1 , as performed by the first radio network node or the second radio network node.

24. A computer-readable storage medium, having stored thereon a computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to any of the claims 1-1 1 , as performed by the first radio network node or the second radio network node.