WO2019145036A1

WO2019145036A1 - Communication connection control procedure selecting a communication connection slice

Info

Publication number: WO2019145036A1
Application number: PCT/EP2018/051850
Authority: WO
Inventors: Harri POVELAINEN; Mikko Tirronen
Original assignee: Nokia Solutions and Networks Oy
Current assignee: Nokia Solutions and Networks Oy
Priority date: 2018-01-25
Filing date: 2018-01-25
Publication date: 2019-08-01
Anticipated expiration: 2020-07-25

Abstract

An apparatus for use by a core network control element or function configured to execute a communication connection related control for session management, the apparatus comprising at least one processing circuitry, and at least one memory for storing instructions to be executed by the processing circuitry, wherein the at least one memory and the instructions are configured to, with the at least one processing circuitry, cause the apparatus at least: to receive a request for establishing a communication connection for a communication element, wherein the request includes session management information comprising at least one of an access point name and a quality of service requirement indication, to process the request by decoding the session management information for obtaining the at least one of the access point name and the quality of service requirement indication, to check whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, and in case a specific network slice is dedicated for the obtained at least one of the access point name and the quality of service requirement indication, to send a rerouting indication to a communication network control element or function for access and mobility management, wherein the rerouting indication comprises network slice specific information and an indication to reroute the request for establishing the communication connection.

Description

COMMUNICATION CONNECTION CONTROL PROCEDURE SELECTING A COMMUNICATION CONNECTION SLICE

DESCRIPTION

BACKGROUND

Field

The present invention relates to apparatuses, methods, systems, computer programs, computer program products and computer-readable media usable for conducting a communication connection control procedure for selecting a network slices or communication connection slice for a communication connection of a communication element, such as a UE, and in particular to a communication connection control procedure where a core network control element or function can select a network slice in a communication network of a first type, such as a next generation network like a 5G communication network, which employs network slicing techniques, for a communication element such as a UE which is configured for a communication network of another (i.e. second type) which does not use network slicing techniques like that of the communication network of the first type, such as an LTE type communication network.

Background Art

The following description of background art may include insights, discoveries, understandings or disclosures, or associations, together with disclosures not known to the relevant prior art, to at least some examples of embodiments of the present invention but provided by the invention. Some of such contributions of the invention may be specifically pointed out below, whereas other of such contributions of the invention will be apparent from the related context.

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

3GPP 3^rd Generation Partner Project 4G fourth generation

5G fifth generation

AF application function

AMF access and mobility function

AN access network

APN access point name

AUSF authentication server function

BS base station

CN core network

CP control plane

CPU central processing unit

DN data network

eMBB enhanced mobile broadband

eNB evolved node B

EPC evolved packet core

EPS evolved packet system

ESM EPS session management

ETSI European Telecommunications Standards Institute gNB next generation Node B

IP Internet protocol

LTE Long Term Evolution

LTE-A LTE Advanced

mMTC massive machine type communications

NAS non access stratum

NEF network exposure function

NR new radio

NRF network repository function

NSSAI network slice selection assistance information

NSSF network slice selection function

PCF policy control function

PDP packet data protocol

PDU packet data unit

PLMN public land mobile network

QoS quality of service

RAN radio access network RAT radio access technology

RRC radio resource control

SMF session and mobility management function

UDM unified data management

UE user equipment

ULA update location answer

ULR update location request

UMTS universal mobile telecommunication system

UP user plane

UPF user plane function

URLLC ultra-reliable low latency communications

SUMMARY

According to an example of an embodiment, there is provided, for example, an apparatus for use by a core network control element or function configured to execute a communication connection related control for session management, the apparatus comprising at least one processing circuitry, and at least one memory for storing instructions to be executed by the processing circuitry, wherein the at least one memory and the instructions are configured to, with the at least one processing circuitry, cause the apparatus at least: to receive a request for establishing a communication connection for a communication element, wherein the request includes session management information comprising at least one of an access point name and a quality of service requirement indication, to process the request by decoding the session management information for obtaining the at least one of the access point name and the quality of service requirement indication, to check whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, and in case a specific network slice is dedicated for the obtained at least one of the access point name and the quality of service requirement indication, to send a rerouting indication to a communication network control element or function for access and mobility management, wherein the rerouting indication comprises network slice specific information and an indication to reroute the request for establishing the communication connection. Furthermore, according to an example of an embodiment, there is provided, for example, a method for use in a core network control element or function configured to execute a communication connection related control for session management, the method comprising receiving a request for establishing a communication connection for a communication element, wherein the request includes session management information comprising at least one of an access point name and a quality of service requirement indication, processing the request by decoding the session management information for obtaining the at least one of the access point name and the quality of service requirement indication, checking whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, and in case a specific network slice is dedicated for the obtained at least one of the access point name and the quality of service requirement indication, sending a rerouting indication to a communication network control element or function for access and mobility management, wherein the rerouting indication comprises network slice specific information and an indication to reroute the request for establishing the communication connection.

According to further refinements, these examples may include one or more of the following features:

- the request for establishing the communication connection may comprise one of an initial attach request of the communication element, a packet data network connectivity request, and request for allocating a communication network resource;

- when checking whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, the obtained at least one of the access point name and the quality of service requirement indication may be sent to a control element or function for unified data management, and an answer from the control element or function for unified data management may be received and processed, wherein a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication may be determined to be present when the answer includes corresponding target slice information and subscriber information.

- in the rerouting indication to be sent to the communication network control element or function for access and mobility management, the target slice information and the subscriber information may be included; - a communication with the control element or function for unified data management may be executed by using one of an update location related signaling, and a signaling for providing subscriber information by using a signaling container;

- when checking whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present results in that no specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, a processing for establishing the communication connection according to the request may be conducted;

- the processing may be implemented in a core network control element or function for session management for controlling a communication connection in a communication network of a first type, and the communication element for which the communication connection is established may be configured to communicate in a communication network of a second type being different to the first type.

In addition, according to an example of an embodiment, there is provided, for example, an apparatus for use by a core network control element or function configured to execute a communication connection related control for access and mobility management, the apparatus comprising at least one processing circuitry, and at least one memory for storing instructions to be executed by the processing circuitry, wherein the at least one memory and the instructions are configured to, with the at least one processing circuitry, cause the apparatus at least: to receive a request for establishing a communication connection for a communication element, wherein the request includes session management information comprising at least one of an access point name and a quality of service requirement indication, to select a core network control element or function for session management serving the communication element, to forward the request for establishing the communication connection to selected core network control element or function for session management, to receive, from the selected core network control element or function for session management, a rerouting indication, wherein the rerouting indication comprises network slice specific information for a specific network slice dedicated for the at least one of the access point name and the quality of service requirement indication, and an indication to reroute the request for establishing the communication connection, to obtain information indicating a new core network control element or function for session management related to a dedicated network slice, to forward the request for establishing the communication connection to the new core network control element or function for session management related to the dedicated network slice, and to conduct a processing for establishing the communication connection with the new core network control element or function for session management related to the dedicated network slice.

Furthermore, according to an example of an embodiment, there is provided, for example, a method for use in a core network control element or function configured to execute a communication connection related control for access and mobility management, the method comprising receiving a request for establishing a communication connection for a communication element, wherein the request includes session management information comprising at least one of an access point name and a quality of service requirement indication, selecting a core network control element or function for session management serving the communication element, forwarding the request for establishing the communication connection to selected core network control element or function for session management, receiving, from the selected core network control element or function for session management, a rerouting indication, wherein the rerouting indication comprises network slice specific information for a specific network slice dedicated for the at least one of the access point name and the quality of service requirement indication, and an indication to reroute the request for establishing the communication connection, obtaining information indicating a new core network control element or function for session management related to a dedicated network slice, forwarding the request for establishing the communication connection to the new core network control element or function for session management related to the dedicated network slice, and conducting a processing for establishing the communication connection with the new core network control element or function for session management related to the dedicated network slice.

- when the rerouting indication is not received, processing for establishing the communication connection with the serving core network control element or function for session management may be conducted; - as the core network control element or function for session management serving the communication element, one of a default core network control element or function for session management and a previously determined core network control element or function for session management related to a network slice may be selected;

- the rerouting indication may comprise target slice information and subscriber information of the communication element;

- when obtaining the information indicating the new core network control element or function for session management related to the dedicated network slice, the target slice information may be sent to a core network control element or function for providing network function related information, and, from the core network control element or function for providing network function related information, slice specific session management function information indicating the new core network control element or function for session management related to the dedicated network slice may be received and processed;

- the processing may be implemented in a core network control element or function for access and mobility management for controlling a communication connection in a communication network of a first type, and the communication element for which the communication connection is established may be configured to communicate in a communication network of a second type being different to the first type.

In addition, according to embodiments, there is provided, for example, a computer program product for a computer, including software code portions for performing the steps of the above defined methods, when said product is run on the computer. The computer program product may include a computer-readable medium on which said software code portions are stored. Furthermore, the computer program product may be directly loadable into the internal memory of the computer and/or transmittable via a network by means of at least one of upload, download and push procedures.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 shows a diagram illustrating a communication network configuration in which examples of embodiments of the invention are implementable; Fig. 2 shows a signaling diagram illustrating a processing for selecting a network slice for a communication connection according to some examples of embodiments;

Fig. 3 shows a signaling diagram illustrating a processing for selecting a network slice for a communication connection according to some examples of embodiments;

Fig. 4 shows a signaling diagram illustrating a processing for selecting a network slice for a communication connection according to some examples of embodiments;

Fig. 5 shows a flow chart of a communication connection control procedure executed by a core network control element or function for session management like an SMF according to some examples of embodiments;

Fig. 6 shows a flow chart of a communication connection control procedure executed by a core network control element or function for access and mobility management like an AMF according to some examples of embodiments;

Fig. 7 shows a diagram of a network element or function acting as a core network control element for session management according to some examples of embodiments;

Fig. 8 shows a diagram of a network element or function acting as a core network control element for access and mobility management according to some examples of embodiments; and

Fig. 9 shows a diagram illustrating a communication network configuration in which examples of embodiments of the invention are implementable.

DESCRIPTION OF EMBODIMENTS

In the last years, an increasing extension of communication networks, e.g. of wire based communication networks, such as the Integrated Services Digital Network (ISDN), DSL, or wireless communication networks, such as the cdma2000 (code division multiple access) system, cellular 3^rd generation (3G) like the Universal Mobile Telecommunications System (UMTS), fourth generation (4G) communication networks or enhanced communication networks based e.g. on LTE or LTE-A, fifth generation (5G) communication networks, cellular 2^nd generation (2G) communication networks like the Global System for Mobile communications (GSM), the General Packet Radio System (GPRS), the Enhanced Data Rates for Global Evolution (EDGE), or other wireless communication system, such as the Wireless Local Area Network (WLAN), Bluetooth or Worldwide Interoperability for Microwave Access (WiMAX), took place all over the world. Various organizations, such as the European Telecommunications Standards Institute (ETSI), the 3^rd Generation Partnership Project (3GPP), Telecoms & Internet converged Services & Protocols for Advanced Networks (TISPAN), the International Telecommunication Union (ITU), 3^rd Generation Partnership Project 2 (3GPP2), Internet Engineering Task Force (IETF), the IEEE (Institute of Electrical and Electronics Engineers), the WiMAX Forum and the like are working on standards or specifications for telecommunication network and access environments.

Generally, for properly establishing and handling a communication between two or more end points (e.g. communication stations or elements, such as terminal devices, user equipments (UEs), or other communication network elements, a database, a server, host etc.), one or more network elements or functions (e.g. virtualized network functions), such as communication network control elements, for example access network elements like access points, radio base stations, relay stations, eNBs, gNBs etc., and core network elements or functions, for example control nodes, support nodes, service nodes, gateways etc., may be involved, which may belong to one communication network system or different communication network systems.

Next-generation (also referred to as 5G) networks will provide significant improvements for achieving a fully mobile and connected society. A variety of new use cases and business models is under discussion as being available for customers. For example, 5G networks will provide services capable for eMBB (enhanced Mobile Broadband), mMTC (massive Machine Type Communications) and URLLC (Ultra-Reliable and Low Latency Communications), which have differing requirements for resources.

However, for providing sufficient capabilities in the communication networks to allow this, it is necessary to rethink the structure of communication networks and in particular mobile networks to support very diverse and extreme requirements for e.g. latency, throughput, capacity, and availability. Traditionally, telecommunication networks mainly target mobile phone like devices (e.g. smartphones, tablets, etc.)· However, in future network architectures, such as 5G networks, the mobile network needs to serve a wide variety of devices (e.g. vehicular devices, etc.) with different requirements. Hence, as one approach to reach this, a shift from the current network of entities architecture to a network of capabilities architecture is considered.

In order to achieve this, a concept called network slicing is employed. Network slicing describes the idea of providing multiple isolated network slices for a variety of services on a common infrastructure in order to scale the network and guarantee best possible service efficient usage of resources. For example, slicing is based on using virtualization technology to architect, partition and organize computing and communication resources of a physical infrastructure to enable flexible support of diverse use case realizations. With network slicing, one physical network is sliced into multiple virtual networks, each architected and optimized for a specific requirement and/or specific application/service.

For example, a network slice is composed of a collection of logical customized network functions that supports the communication service requirements. The operator’s physical network is sliced into multiple virtual and end-to-end networks and each slice is logically isolated. Each slice has a dedicated treatment in terms of performance (e.g. latency, throughput, etc.) or functionality (e.g. resiliency, security, etc.).

A network slice represents a logical end-to-end network that can be dynamically created. A UE as a communication element can have access to multiple network slices over different or the same access network. For example, a network slice is defined within a PLMN and includes the core network control plane a user plane network functions as well as an access network, such as a NG access network or another type of access network (e.g. Wi-Fi based).

For identifying a network slice, NSSAI is usable which indicates an expected network slice behaviour in terms of features and services (e.g. for indicating a slice suitable for eMBB, mMTC or URLLC), and comprises optionally information allowing to differentiate amongst multiple network slices of the same type. The NSSAI is sent in signalling messages between the UE and the 5G network. For example, a single UE may be served by a plurality of network slices at a time each being identified by a NSSAI element. The NSSAI signalled by the UE to the network assists the network in selecting a particular network slice instance. Information in the NSSAI may be associated with a PLMN (e.g., PLMN ID) and have network-specific values or have standard values.

Usually, the network slice selection for a UE is triggered as part of the registration procedure, e.g. by a first AMF that receives the registration request from the UE. The AMF retrieves the slices that are allowed by the user subscription and interacts with a network slice selection function (NSSF) to select the appropriate network slice instance.

That is, NSSAI in 5G networks is used for establishing PDU session (e.g. when the AMF receives a session management message from the UE), for discovering and selecting a suitable candidate SMF, and selecting a suitable user plane function (UPF) by the SMF. A network repository function (NRF) is used for the discovery of the required network functions. Data transmission can take place after a PDU session to a data network is established in the network slice.

That is, slice selection of devices according to the 5G specification protocols is specified by using the NSSAI. However, especially in a transition phase to 5G networks, there are hundreds of millions legacy devices (i.e. devices such as UEs or other terminal devices which are configured according to former standards, such as 4G (LTE) standards) which are not able to provide the necessary signaling, such as the NSSAI signaling, in order to assist in the selection of a network slice. For example, NSSAI is not provided via RRC and NAS signalling as stated in the 5G specifications.

In this context, it is to be noted that 5G core network architecture is based on the concept to separate mobility management and session management functions to different network functions (i.e. AMF and SMF, respectively). Therefore, a network slice selection using information such as an APN is not directly available as the required information is not available in the AMF which is the network function performing the SMF selection, as described above.

Consequently, the present invention is related to provide a configuration allowing to perform a network slice selection also for devices (e.g. UEs) which are not configured for 5G procedures, i.e. for devices which do not support 5G based network slice selection (e.g. LTE based devices).

Specifically, according to examples of embodiments being discussed in the following, a process is described which enables that the AMF can make the network slice selection for a UE even when no NSSAI or other slice type information is obtained from the UE (e.g. in case the UE is a LTE based UE). Instead, on the basis of information like the APN requested by the UE, or on the basis of QoS requirements, a process is executed where an SMF asks for slice type information at a UDM. If there is a specific slice dedicated for this APN, the first SMF is able to reject the AMF request and force the AMF to reselect another SMF, wherein the slice type information received from the UDM are used as the basis for the reselection.

In the following, different exemplifying embodiments will be described using, as an example of a communication network to which the embodiments may be applied, a communication network architecture based on 3GPP standards for 5G communication networks, without restricting the embodiments to such architectures, however. It is obvious for a person skilled in the art that the embodiments may also be applied to other kinds of communication networks having suitable means by adjusting parameters and procedures appropriately, e.g. 4G networks, Wi-Fi, worldwide interoperability for microwave access (WiMAX), Bluetooth®, personal communications services (PCS), ZigBee®, wideband code division multiple access (WCDMA), systems using ultra- wideband (UWB) technology, mobile ad-hoc networks (MANETs), wired access, etc.. Furthermore, without loss of generality, the description of some examples of embodiments is related to a mobile communication network, but principles of the invention can be extended and applied to any other type of communication network, such as a wired communication network.

The following examples and embodiments are to be understood only as illustrative examples. Although the specification may refer to“an”,“one”, or“some” example(s) or embodiment(s) in several locations, this does not necessarily mean that each such reference is related to the same example(s) or embodiment(s), or that the feature only applies to a single example or embodiment. Single features of different embodiments may also be combined to provide other embodiments. Furthermore, terms like “comprising” and “including” should be understood as not limiting the described embodiments to consist of only those features that have been mentioned; such examples and embodiments may also contain features, structures, units, modules etc. that have not been specifically mentioned.

A basic system architecture of a (tele)communication network including a mobile communication system where some examples of embodiments are applicable may include an architecture of one or more communication networks including wireless access network subsystem(s) and core network(s). Such an architecture may include one or more communication network control elements or functions, access network elements, radio access network elements, access service network gateways or base transceiver stations, such as a base station (BS), an access point (AP), a NodeB (NB), an eNB or a gNB, a distributed or a centralized unit, which control a respective coverage area or cell(s) and with which one or more communication stations such as communication elements, user devices or terminal devices, like a UE, or another device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of a station, an element, a function or an application capable of conducting a communication, such as a UE, an element or function usable in a machine-to-machine communication architecture, or attached as a separate element to such an element, function or application capable of conducting a communication, or the like, are capable to communicate via one or more channels for transmitting several types of data in a plurality of access domains. Furthermore, core network elements or network functions, such as gateway network elements/functions, mobility management entities, a mobile switching center, servers, databases and the like may be included.

The general functions and interconnections of the described elements and functions, which also depend on the actual network type, are known to those skilled in the art and described in corresponding specifications, so that a detailed description thereof is omitted herein. However, it is to be noted that several additional network elements and signaling links may be employed for a communication to or from an element, function or application, like a communication endpoint, a communication network control element, such as a server, a gateway, a radio network controller, and other elements of the same or other communication networks besides those described in detail herein below.

A communication network architecture as being considered in examples of embodiments may also be able to communicate with other networks, such as a public switched telephone network or the Internet. The communication network may also be able to support the usage of cloud services for virtual network elements or functions thereof, wherein it is to be noted that the virtual network part of the telecommunication network can also be provided by non-cloud resources, e.g. an internal network or the like. It should be appreciated that network elements of an access system, of a core network etc., and/or respective functionalities may be implemented by using any node, host, server, access node or entity etc. being suitable for such a usage.

Furthermore, a network element, such as communication elements, like a UE, a terminal device, control elements or functions, such as access network elements, like a base station (BS), an gNB, a radio network controller, a core network control element or function, such as a SMF, an AMF, an UDM, a gateway element, or other network elements or functions, as described herein, and any other elements, functions or applications may be implemented by software, e.g. by a computer program product for a computer, and/or by hardware. For executing their respective processing, correspondingly used devices, nodes, functions or network elements may include several means, modules, units, components, etc. (not shown) which are required for control, processing and/or communication/signaling functionality. Such means, modules, units and components may include, for example, one or more processors or processor units including one or more processing portions for executing instructions and/or programs and/or for processing data, storage or memory units or means for storing instructions, programs and/or data, for serving as a work area of the processor or processing portion and the like (e.g. ROM, RAM, EEPROM, and the like), input or interface means for inputting data and instructions by software (e.g. floppy disc, CD- ROM, EEPROM, and the like), a user interface for providing monitor and manipulation possibilities to a user (e.g. a screen, a keyboard and the like), other interface or means for establishing links and/or connections under the control of the processor unit or portion (e.g. wired and wireless interface means, radio interface means including e.g. an antenna unit or the like, means for forming a radio communication part etc.) and the like, wherein respective means forming an interface, such as a radio communication part, can be also located on a remote site (e.g. a radio head or a radio station etc.). It is to be noted that in the present specification processing portions should not be only considered to represent physical portions of one or more processors, but may also be considered as a logical division of the referred processing tasks performed by one or more processors. It should be appreciated that according to some examples, a so-called“liquid” or flexible network concept may be employed where the operations and functionalities of a network element, a network function, or of another entity of the network, may be performed in different entities or functions, such as in a node, host or server, in a flexible manner. In other words, a“division of labor” between involved network elements, functions or entities may vary case by case.

Fig. 1 and Fig. 9 show a respective diagram illustrating a communication network configuration in which examples of embodiments of the invention are implementable. Specifically, Figs. 1 and 9 show a respective architecture of a communication network including a next generation (5G) core network structure.

While in communication networks such as 4G networks protocols and reference points are defined for each entity (such as Mobility Management Entity (MME), Serving Gateway (S-GW), and Packet Data Network Gateway (P-GW)), in next generation networks like 5G networks protocols and reference points are defined for network functions (NF) and reference points connecting NFs.

Basically, there are two ways of representing a next generation architecture. One is a so-called a point-to-point architecture which is the basis of the configuration of Fig. 1. Another representation is a so-called a service-based architecture as shown in Fig. 9. Both types of architecture comprise, more or less, the same functional elements wherein a splitting of control and user plane is considered. Furthermore, several interfaces are the same. Flowever, the point-to-point architecture shown in Fig. 1 is similar a traditional 3GPP architecture, as it defines functions and interfaces between them. The service- based architecture as shown in Fig. 9 incorporates basically the same functional elements and the same user-plane processing path between a UE and an external data networks, but in the control plane, a services model is used in which components query a network repository function NRF to discover and communicate with each other. This approach is more related to a cloud-native networking concept in which libraries of functions can be requested from a virtualized network function catalog and composed into end-to-end service chains on demand. Generally, a network function can be implemented either as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, or as a virtualized function instantiated on an appropriate platform, e.g., a cloud infrastructure.

As shown in Fig. 1 , a communication element such as a user equipment (UE) 10 is connected to a RAN or access network (AN) 20 and to an access and mobility function (AMF) 50. The RAN 20 represents a base station (BS or NB) using a NR RAT and/or an evolved LTE base station, while AN 20 is a general base station including e.g. non-3GPP access, e.g., Wi-Fi.

The core network architecture shown in Fig. 1 applied for a 5G network comprises various NFs. As shown in Fig. 1 , the CN NFs comprises the AMF 50, a session management function (SMF) 40, a policy control function (PCF) 60, an application function (AF) 90, an authentication server function (AUSF) 70, a network slice selection function (NSSF) 75, a user plane function (UPF) 30, and a user data management (UDM) 80. Further elements, which are not shown in Fig. 1 , belonging to the CN NFs include, for example, an NRF and the like which is used for providing network function related information.

The AMF 50 provides UE-based authentication, authorization, mobility management, etc. A UE (e.g. UE 10) even using multiple access technologies is basically connected to a single AMF because the AMF 50 is independent of the access technologies.

The SMF 40 sets up and manages sessions according to network policy. The SMF 40 is responsible, for example, for session management and allocates IP addresses to UEs. Furthermore, it selects and controls the UPF 30 for data transfer.

It is to be noted that it is also possible that in case the UE 10 has e.g. multiple sessions (communication connections), different SMFs may be allocated to each session to manage them individually and possibly provide different functionalities per session.

The UPF 30 can be deployed in various configurations and locations, according to the service type. Functions of the UPF 30 are e.g. QoS handling for user plane, packet routing and forwarding, packet inspection and policy rule enforcement, traffic accounting and reporting. The PCF 60 provides a policy framework incorporating network slicing, roaming and mobility management, similar to a policy and charging rules function in a 4G network.

The AF 90 provides information on the packet flow to the PCF 60 in order to support QoS. Based on the information, the PCF 60 determines policies about mobility and session management to make the AMF 50 and the SMF 40 operate properly.

The AUSF 70 stores and provides data for authentication of the UE 10. The NSSF 75 selects network slice instances. The UDM 80 stores and provides subscription data of the UE 10, similar to a home subscriber server (FISS) in 4G networks, and also network slice specific information.

Furthermore, a data network 100 (e.g. the Internet) is shown in Fig. 1 which are not part of the core network architecture, for providing access to the Internet or to operator services.

As shown in Fig. 1 , the NFs are connected by means of so-called reference points N1 to N15 and N22. This representation of reference points N1 to N15 and N22 is used for illustrating how call flows are developed. For example, N1 is defined to carry signaling between the UE 10 and the AMF 50. The reference point for connecting between the RAN/AN 20 and the AMF 50 is defined as N2, and the reference point between RAN/AN 20 and the UPF 30/35 is defined as N3, respectively. A reference point N11 is defined between the AMF 50 and the SMF 40 so that SMF 40 is controllable by the AMF 50. Reference point N22 is defined between the AMF 50 and the NSSF 75. Reference point N4 is used by the SMF 40 and the UPF 30 so that the UPF 30 can be set using the control signal generated by the SMF 40, and the UPF 30 can report its state to the SMF 40. Reference point N9 is the reference point for the connection between different UPFs, and reference point N14 is the reference point connecting between different AMFs, respectively. Reference point N15 and N7 are defined for connecting the PCF 60 to the AMF 50 and the SMF 40, respectively, so that the PCF 60 can apply policy to the AMF 50 and the SMF 40, respectively. Reference point N12 to AUSF 70 is required for the AMF 50 to perform authentication of the UE 10. Reference points N8 and N10 are defined because the subscription data of the UE 10 is required for the AMF 50 and the SMF 40, respectively. Reference point N5 is defined for connecting between the AF 90 and the PCF 60, and reference point N13 is defined for connecting between the AUSF 70 and the UDM 80. Reference points N6 are defined for connecting between the UPF 30 and the DN 100.

On the other hand, in the service-based architecture shown in Fig. 9, basically the same functional elements and the same user-plane processing path between the UE 10 and external data network 100 are provided. The major difference of the architecture according to Fig. 9 is in the control plane, where, instead of predefined interfaces between the elements/functions, a services model is used in which the components query the NRF to discover and communicate with each other. That is, in the configuration according to Fig. 9, the NRF 77 and a NEF 76 are illustrated.

It is to be noted that the NRF 77 and the NSSF 75 can be the same or separate elements or functions. Furthermore, even though NEF 76 and NRF 77 are not illustrated in the point-to-point architecture as shown in Fig. 1 , NEF and NRF elements or functions can be also included therein; all depicted network functions can interact with the NEF and NRF as necessary.

In the control plane of the architecture according to Fig. 9, the network function NSSF 75 is linked to other network functions via Nnssf interface, the network function NEF 76 is linked to other network functions via Nnef interface, the network function NRF 76 is linked to other network functions via Nnrf interface, the network function PCF 60 is linked to other network functions via Npcf interface, the network function UDM 80 is linked to other network functions via Nudm interface, the network function AF 90 is linked to other network functions via Naf interface, the network function AUSF 70 is linked to other network functions via Nausf interface, the network function AMF 50 is linked to other network functions via Namf interface, and the network function SMF 40 is linked to other network functions via Nsmf interface. It is to be noted that in the following reference is made to the interfaces shown in Fig. 1 when explaining signaling between respective network functions, but it is evident that the corresponding interfaces as shown in Fig. 9 can be used in an equivalent manner.

As indicated above, in the network configuration as shown in Fig. 1 (or Fig. 9), a separation of control plane and the user plane is considered. The user plane carries user traffic while the control plane carries signaling in the network. In Fig. 1 , the UPF 30 is in the user plane and the AMF 50, the SMF 40, the PCF 60, the AF 90, the AUSF 70, the NSSF and the UDM 80 are in the control plane (the same applies for the NRF (not shown). Separating the user and control planes guarantees each plane resources to be scaled independently. It also allows UPFs to be deployed separately from control plane functions in a distributed fashion. For example, UPFs can be deployed very close to RAN or UEs to shorten a round trip time (RTT) between the UE and data network for some applications requiring low latency.

Generally, each NF interacts with another NF directly, but it is also possible that an intermediate function is used for routing messages from one NF to another NF. In the control plane, a set of interactions between two NFs is defined as service so that its reuse is possible. The user plane supports interactions such as forwarding operations between different UPFs.

According to examples of embodiments, it is assumed that the core network control elements and functions, in particular the AMF 50 and the SMF 40, are able to handle also messages being configured according to non-5G specifications, such as LTE S1 AP and NAS messages. This is beneficial to be able to gain the benefit of the 5G network functions (i.e. scaling, slicing, etc.) also for non-5G devices, such as LTE devices.

Fig. 2 shows a signaling diagram illustrating a processing for selecting a network slice for a communication connection according to some examples of embodiments. In Fig. 2, a situation is illustrated where the UE 10 initially requests for establishing a communication connection with the communication network as depicted in Fig. 1 (or Fig. 9), i.e. with the 5G network. The UE 10 is, for example, an LTE device, i.e. the communication network is of a first type (e.g. 5G) and the communication device is configured for a second type of communication network, e.g. an LTE network or another network type. That is, as described above, examples of embodiments of the invention are related to a case where the UE is not prepared to provide information assisting in the network slice selection, such as NSSAI, when requesting to establish a communication connection.

In the example of Fig. 2, it is assumed that the UE 10 requests for a new PDN connection in an initial attach. Basically, a UE has to register with the network to receive services that require registration. This registration is also referred to as initial network attachment. In S10, the UE 10 (e.g. an LTE UE) starts the attach procedure with the core network via the access network, e.g. via the RAN 20. As illustrated in Fig. 1 (or Fig. 9), the core network control element or function communicating with the UE 10 on the control plane is the AMF 50. That is, the UE 10 requests in S10 for a new PDN connection in the initial attach. This request is accompanied by session management information; for example, the UE 10 sends also a request that it is to be connected to a specific APN.

Since this is a session management information, the request should be decoded in the SMF 40. In S20, the AMF 50 conducts a selection processing for selecting the SMF to which the request is to be forwarded. As indicated above, Fig. 2 is related to a case where an initial attach is conducted. Because of this, the AMF 50 selects a default SMF as the target for forwarding the initial PDN Connectivity Request.

In S30, information related to the request received from the UE 10 in S10 are forwarded to the selected SMF (e.g. SMF 40) via N11 interface. Here, in S40, the session management information contained in the request (e.g. ESM) is decoded, i.e. the APN information is retrieved.

With the APN information being known, the (default) SMF 40 conducts a processing for checking whether there is a specific network slice allocated to this APN. For this purpose, in S50, the SMF 40 sends to the UDM 80 a signaling being, for example, the 5G equivalent to an ULR signaling which includes the information retrieved from the session management information, i.e. the APN in this example. With the ULR signaling, the UDM is asked whether there is a specific slice allocated for the APN the UE has requested.

The UDM 80 responds in S55 to the ULR by sending a signaling being, for example, the 5G equivalent to an ULA signaling. On the basis of the information in the ULA, the SMF 40 can determine whether there is a specific network slice allocated to the APN.

When the ULA in S55 indicates that there is no network slice allocated to the APN, the SMF 40 continue with a processing related to the attach request as the serving SMF. That is, a connection establishing procedure is conducted in a normal manner. A corresponding example of such a processing is discussed in connection with S90, for example. On the other hand, in case the ULA in S55 indicates that there is a network slice allocated to the APN, the processing in the (default) SMF is different. For example, in case there is a network slice allocated to the APN, the ULA in S55 contains information indicating the target slice type. In addition, it is to be noted that the ULA includes subscriber profile information.

When receiving, for example, the slice type information from the UDM in S55, the SMF 40 sends in S60 via N11 a rerouting indication to the AMF 50. For example, the SMF 40 forwards in S60 the slice type information received in S55 together with subscriber information to the AMF 50. This includes also an indication that a rerouting for the establishing of the communication connection has to be considered. That is, the default SMF 40 informs the AMF 50 that the request is to be rerouted to a slice specific SMF instance.

When receiving the rerouting indication, the AMF starts a processing for forwarding the request to the correct SMF (in the example of Fig. 2 this is for example a network element or function for session management in a eMBB scenario, which is referred to as SMF for eMBB). For this purpose, the slice type information received from the SMF 40 in S60 are used to request from the NRF_NSSF slice specific SMF information, i.e. the AMF requests information allowing to contact the SMF for eMBB. For example, in S70, the AMF 50 sends a discover request to the NRF_NSSF which includes the target slice type. The NRF_NSSF answers in S75 with a discover response signaling in which the slice specific SMF information is included. That is, in the processing of S70 and S75, the AMF 50 request for information about the SMF (for eMBB) for this specific slice type from the NRF NSSF.

When having received the information in S75, the AMF 50 continues the attach procedure with the slice specific SMF (SMF for eMBB) by forwarding in S80 the request for establishing the communication connection. This request in S80 contains also the subscriber information; that is, it is not necessary to obtain (once more) the subscriber information (e.g. by using an ULR/ULA signaling with the UDM) since the required information is available already in the signaling of S60. Then in S90, the attach procedure started in S10 is continued, wherein the SMF for eMBB is now acting as the serving SMF. In this attach procedure, for example, an initial context is setup and a RRC connection is configured between the UE 10, the RAN 20 and the core network control elements or functions (e.g. the AMF/SMF and the UPF), so that a data transfer (i.e. uplink data and downlink data) can be started.

Fig. 3 shows a signaling diagram illustrating another processing for selecting a network slice for a communication connection according to some examples of embodiments. In Fig. 3, a situation is illustrated where after the initial attach (e.g. processing of Fig. 2) the UE 10 requests for additional PDN connections for different APNs. Again, the network is a communication network is of a first type (e.g. 5G) and the communication device (UE 10) is configured for a second type of communication network, e.g. an LTE network or another network type.

In the example of Fig. 3, it is assumed that the UE 10 requests for an additional PDN connectivity to an additional APN including allocation of a default bearer. In other words, the UE 10 requests, after the initial attach, for additional PDN connections for different APNs.

In S110, the UE 10 sends a new PDN Connectivity request to the core network via the access network, e.g. via the RAN 20, i.e. to the AMF 50 as the core network control element or function communicating with the UE 10 on the control plane. This request comprises session management information, i.e. the APN to which the UE 10 is to be connected which should be decoded in the SMF. Flence, In S120, the AMF 50 selects the serving SMF to which the request is to be forwarded. As indicated above in the processing of Fig. 2, the serving SMF can be either the default SMF 40 or the slice specific SMF ( SMF for eMBB), depending on the result of the processing related to S50, S55.

In the present case, it is assumed that the serving SMF is the SMF for eMBB. In S130, information related to the request received from the UE 10 in S110 is forwarded to the serving SMF via N11 interface. In S140, the session management information contained in the request (e.g. ESM) is decoded, i.e. the APN information is retrieved. With the APN information being known, the SMF for eMBB conducts a processing for checking whether the retrieved APN has a different network slice type, compared the one the UE 10 is already connected to (via the SMF for eMBB).

For this purpose, in S150, the SMF for eMBB sends to the UDM 80 an ULR signaling which includes the information retrieved from the session management information, i.e. the APN in this example. With the ULR signaling, the UDM is asked whether there is a different network slice for the new APN.

The UDM 80 responds in S155 to the ULR by sending an ULA. On the basis of the information in the ULA, the SMF for eMBB can determine whether there is a different network slice allocated to the new APN.

Assuming the case that there is a different network slice for the requested APN, and that the new slice type has higher QoS requirements (e.g. for URLLC). In this case, the UDM allocate the new slice type and includes corresponding target slice type information (together with subscriber profile information) in the ULA in S155.

It is to be noted that in the present example QoS is used as a possible decision criterium in the UDM, the but UDM can also use other mechanisms to decide as to whether a slice change for the UE 10 is needed.

When receiving the new slice type information from the UDM in S155, the SMF for eMBB sends in S160 via N11 a rerouting indication to the AMF 50. For example, the SMF forwards in S160 the new slice type information received in S155 together with subscriber information to the AMF 50. This includes also an indication that a rerouting for the establishing of the communication connection has to be considered. That is, the SMF for eMBB informs the AMF 50 that the request of S110 is to be rerouted to a slice specific SMF instance.

When receiving the rerouting indication, the AMF 50 starts a processing for forwarding the request to the correct SMF (in the example of Fig. 3 this is referred to as SMF for URLLC). That is, the slice type information received from the SMF in S160 is used to request from the NRF_NSSF slice specific SMF information, i.e. the AMF 50 requests information allowing to contact the SMF for URLLC. For example, in S170, the AMF 50 sends a discover request to the NRF NSSF which includes the target slice type. The NRF_NSSF answers in S175 with a discover response signaling in which the slice specific SMF information is included. That is, in the processing of S170 and S175, the AMF 50 requests for information about the SMF for URLLC for the new slice type from the NRF NSSF.

With the information received in S175, the AMF 50 continues the attach procedure with the slice specific SMF (SMF for URLLC) by forwarding in S180 the request for establishing the communication connection. This request in S180 contains also the subscriber information; that is, it is not necessary to obtain (once more) the subscriber information (e.g. by using an ULR/ULA signaling with the UDM) since the required information is available already in the signaling of S160.

Then in S190, the PDN connectivity procedure started in S110 is continued, wherein the SMF for URLLC is now acting as the serving SMF. In this PDN connectivity procedure, for example, a bearer is setup and PDN connectivity is completed by the UE 10, the RAN 20 and the core network control elements or functions (e.g. the AMF/SMF and the UPF) so that a data transfer (i.e. uplink data and downlink data) can be started.

Fig. 4 shows a signaling diagram illustrating another processing for selecting a network slice for a communication connection according to some examples of embodiments. In Fig. 4, a situation is illustrated where the UE 10 requests for a dedicated bearer with specific QoS requirements. That is, in the example according to Fig. 4, QoS information instead of APN information are provided by the UE 10 for the further processing.

Again, the network in the example of Fig. 4 is a communication network is of a first type (e.g. 5G) and the communication device (UE 10) is configured for a second type of communication network, e.g. an LTE network or another network type.

In the example of Fig. 4, it is assumed that the UE 10 requests for a dedicated bearer with specific QoS requirements.

In S210, the UE 10 sends a bearer resource allocation request to the core network via the access network, e.g. via the RAN 20, i.e. to the AMF 50 as the core network control element or function communicating with the UE 10 on the control plane. This request comprises session management information, i.e. QoS requirements which the UE 10 is requesting, which should be decoded in the SMF. Hence, In S220, the AMF 50 selects the serving SMF to which the request is to be forwarded. As indicated above, the serving SMF can be e.g. the default SMF 40 or the slice specific SMF ( SMF for eMBB).

In the present case, it is assumed that the serving SMF is the SMF for eMBB. In S230, information related to the request received from the UE 10 in S210 is forwarded to the serving SMF via N11 interface. In S240, the session management information contained in the request (e.g. ESM) is decoded, i.e. the QoS requirement information is retrieved.

With the QoS information being known, the SMF for eMBB conducts a processing for checking whether the there is a different network slice type for the QoS requirement, compared to the one the UE 10 is already connected to (via the SMF for eMBB).

For this purpose, in S250, the SMF for eMBB sends to the UDM 80 an ULR signaling which includes the information retrieved from the session management information, i.e. the QoS information in this example. With the ULR signaling, the UDM is asked whether there is a different network slice for the QoS.

The UDM 80 responds in S255 to the ULR by sending an ULA. On the basis of the information in the ULA, the SMF for eMBB can determine whether there is a different network slice allocated to the QoS in question.

Assuming the case that there is a different network slice for the QoS, and that the new slice type has higher QoS requirements (e.g. for URLLC). In this case, the UDM allocates the new slice type and includes corresponding target slice type information (together with subscriber profile information) in the ULA in S255.

That is, in the present example, the UDM uses QoS information instead of APN to make selection of the slice type.

When receiving the new slice type information from the UDM in S255, the SMF for eMBB sends in S260 via N11 a rerouting indication to the AMF 50. For example, the SMF forwards in S260 the new slice type information received in S255 together with subscriber information to the AMF 50. This includes also an indication that a rerouting for the establishing of the communication connection has to be considered. That is, the SMF for eMBB informs the AMF 50 that the request of S210 is to be rerouted to a slice specific SMF instance.

When receiving the rerouting indication, the AMF 50 starts a processing for forwarding the request to the correct SMF (in the example of Fig. 4 this is referred to as SMF for URLLC). That is, the slice type information received from the SMF in S260 are used to request from the NRF_NSSF slice specific SMF information, i.e. the AMF 50 requests information allowing to contact the SMF for URLLC. For example, in S270, the AMF 50 sends a discover request to the NRF NSSF which includes the target slice type. The NRF_NSSF answers in S275 with a discover response signaling in which the slice specific SMF information is included. That is, in the processing of S270 and S275, the AMF 50 requests information about the SMF for URLLC for the new slice type from the NRF NSSF.

With the information received in S275, the AMF 50 continues the procedure with the slice specific SMF (SMF for URLLC) by forwarding in S280 the request for establishing the communication connection. This request in S280 contains also the subscriber information; that is, it is not necessary to obtain (once more) the subscriber information (e.g. by using an ULR/ULA signaling with the UDM) since the required information is available already in the signaling of S260.

Then in S290, the procedure started in S210 is continued for creating a dedicated bearer, wherein the SMF for URLLC is now acting as the serving SMF. In this bearer creation procedure, for example, RRC connection is reconfigured between the UE 10, the RAN 20 and the core network control elements or functions (e.g. the AMF/SMF and the UPF), and a bearer is setup.

According to examples of embodiments, it is also possible to deliver subscriber information in a container from the UDM 80 to the SMF (e.g. SMF 40). That is, according to corresponding examples of embodiments, a container may be used for AMF-specific subscriber information and another container may be used for SMF-specific subscriber information. These containers can be requested by the AMF or pushed by the UDM. Subscriber information for a UE is transported from the UDM to the AMF by using such transparent containers. The AMF decodes the AMF-specific subscriber information received via the transparent containers during a registration procedure, and subsequently provides the SMF-specific subscriber information to the SMF over an interface, e.g. during a PDU session creation procedure. Furthermore, a transparent container can be established over N11 interface between the AMF and the SMF for conveying the subscriber information associated with the UE.

Fig. 5 shows a flow chart of a communication connection control procedure executed by a core network control element or function for session management like the SMF 40 shown in Fig. 1 (or Fig. 9), according to some examples of embodiments.

In S300, a request for establishing a communication connection for a communication element, such as the UE 10, is received, for example, from a core network control element or function for access and mobility management, like the AMF 50. The request includes session management information comprising at least one of an access point name and a QoS requirement indication. According to examples of embodiments, the request for establishing the communication connection comprises one of an initial attach request of the UE, a PDN connectivity request, and a request for allocating a communication network resource, such as a dedicated bearer.

In S310, the request is processed by decoding the session management information for obtaining the at least one of the access point name and the quality of service requirement indication.

In S320 it is checked whether a specific network slice dedicated for the obtained at least one of the access point name and the QoS requirement indication is present.

For example, according to some examples of embodiments, it is checked whether a specific network slice dedicated for the obtained at least one of the access point name and the QoS requirement indication is present by means of the following processing. The obtained at least one of the access point name and the QoS requirement indication is sent to a control element or function for unified data management, such as UDM 80. In response, an answer from the UDM 80 is received which is processed for determining the presence of such a specific network slice. For example, the specific network slice dedicated for the obtained at least one of the access point name and the QoS requirement indication is determined to be present when the answer includes corresponding target slice information and subscriber information. That is, in S330, based on S320, in case it is determined that a specific network slice is present for the obtained at least one of the access point name and the QoS requirement indication, the process is directed to S340.

In S340, a rerouting indication is sent to the AMF 50, wherein the rerouting indication comprises network slice specific information and an indication to reroute the request for establishing the communication connection. That is, according to some examples of embodiments, the target slice information and the subscriber information received from the UDM 80 are included in the rerouting indication to be sent to the AMF 50.

According to examples of embodiments, a communication with the control element or function for unified data management (e.g. UDM 80) is executed by using an update location related signaling (i.e. ULR and ULA, for example). Alternatively, a signaling between the UDM 80 and the SMF 40 (or the AMF 50) for providing subscriber information by using a signaling container is executed.

On the other hand, according to some examples of embodiments, when it is determined in S320 and S330 that there is no specific network slice dedicated for the obtained at least one of the access point name and the QoS requirement indication, e.g. when the answer includes no target slice information, the process is directed from S330 to S350.

In S350, when no specific network slice dedicated for the obtained at least one of the access point name and the QoS requirement indication is determined, the SMF 40 conducts a processing for establishing the communication connection according to the request (i.e. the SMF receiving the request in S300 is the serving SMF for the communication establishment, such as initial attach, PDN connectivity, etc.).

According to some examples of embodiments, the above described processing according to S300 to S350 is executed by a core network control element or function for session management like the SMF 40 which is configured to control a communication connection in a communication network of a first type, such as in a 5G network. On the other hand, the communication element like the UE 10 for which the communication connection is established is configured for a communication in a communication network of a second type being different to the first type, such as in a 4G or LTE based network (i.e. an LTE UE).

Fig. 6 shows a flow chart of a communication connection control procedure executed by a core network control element or function for access and mobility management like the AMF 50 according to some examples of embodiments.

In S400, a request for establishing a communication connection for a communication element, such as the UE 10, is received, wherein the request includes session management information comprising at least one of an access point name and a QoS requirement indication. For example, the request for establishing the communication connection comprises one of an initial attach request of the UE 10, a PDN connectivity request, and request for allocating a communication network resource, such as a dedicated bearer.

In S410, a core network control element or function for session management (i.e. an SMF) for serving the UE 10 is selected. The request for establishing the communication connection is forwarded to the selected core network control element or function for session management. According to examples of embodiments, as the core network control element or function for session management serving the UE 10, one of a default core network control element or function for session management (e.g. SMF 40) and a previously determined core network control element or function for session management related to a network slice (such as the SMF for eMBB shown in Figs. 2 to 4) is selected by the AMF 50.

In S420, the AMF 50 receives from the selected core network control element or function for session management a rerouting indication. The rerouting indication comprises network slice specific information for a specific network slice dedicated for the at least one of the access point name and the QoS requirement indication, and an indication to reroute the request for establishing the communication connection. In other words, the AMF 50 is forced to reselect another SMF.

According to examples of embodiments, the rerouting indication comprises target slice information and subscriber information of the UE 10. In S430, information indicating a new core network control element or function for session management related to a dedicated network slice is obtained. According to examples of embodiments, when obtaining the information indicating the new core network control element or function for session management related to the dedicated network slice, the target slice information is sent to a core network control element or function for providing network function related information, such as the NSSF and/or NRF. From this core network control element or function for providing network function related information (i.e. NSSF and/or NRF), the AMF 50 receives and processes slice specific SMF information indicating the new SMF (e.g. the SMF for eMBB or the SMF for URLLC as discussed in connection with Figs. 2 to 4) as the core network control element or function for session management related to the dedicated network slice.

In S440, the request for establishing the communication connection is forwarded to the new core network control element or function for session management related to the dedicated network slice (e.g. the SMF for eMBB or the SMF for URLLC as discussed in connection with Figs. 2 to 4).

In S450, the AMF 50 conducts a processing for establishing the communication connection with the new core network control element or function for session management related to the dedicated network slice.

It is to be noted that according to some examples of embodiments, when the rerouting indication is not received in S420, a processing for establishing the communication connection with the (currently) serving core network control element or function for session management. is executed, which is similar to the processing of S450.

According to some examples of embodiments, the above described processing according to S400 to S450 is executed by a core network control element or function for access and mobility management like the AMF 50 which is configured to control a communication connection in a communication network of a first type, such as in a 5G network. On the other hand, the communication element like the UE 10 for which the communication connection is established is configured for a communication in a communication network of a second type being different to the first type, such as in a 4G or LTE based network (i.e. an LTE UE). Fig. 7 shows a diagram of a network element or function acting as a core network control element for session management according to some examples of embodiments, e.g. the SMF 40 of Fig. 1 (or Fig. 9), which is configured to conduct a communication connection control procedure as described in connection with some of the examples of embodiments. It is to be noted that the control element or function, like the SMF 40 of Fig. 1 (or Fig. 9), may include further elements or functions besides those described herein below. Furthermore, even though reference is made to a network control element or function, the element or function may be also another device or function having a similar task, such as a chipset, a chip, a module, an application etc., which can also be part of a network element or attached as a separate element to a network element, or the like. It should be understood that each block and any combination thereof may be implemented by various means or their combinations, such as hardware, software, firmware, one or more processors and/or circuitry.

The network control element like the SMF 40 shown in Fig. 7 may include a processing circuitry, a processing function, a control unit or a processor 401 , such as a CPU or the like, which is suitable for executing instructions given by programs or the like related to the communication connection control procedure. The processor 401 may include one or more processing portions or functions dedicated to specific processing as described below, or the processing may be run in a single processor or processing function. Portions for executing such specific processing may be also provided as discrete elements or within one or more further processors, processing functions or processing portions, such as in one physical processor like a CPU or in one or more physical or virtual entities, for example. Reference signs 402 and 403 denote input/output (I/O) units or functions (interfaces) connected to the processor or processing function 401. The I/O units 402 may be used for communicating with the AMF, as described in connection with Fig. 1 (or Fig. 9), for example. The I/O units 403 may be used for communicating with the UDM, as described in connection with Fig. 1 (or Fig. 9), for example. The I/O units 402 and 403 may be a combined unit including communication equipment towards several entities, or may include a distributed structure with a plurality of different interfaces for different entities. Reference sign 404 denotes a memory usable, for example, for storing data and programs to be executed by the processor or processing function 401 and/or as a working storage of the processor or processing function 401. It is to be noted that the memory 404 may be implemented by using one or more memory portions of the same or different type of memory.

The processor or processing function 401 is configured to execute processing related to the above described communication connection control processing. In particular, the processor or processing circuitry or function 401 includes one or more of the following sub-portions. Sub-portion 4011 is a processing portion which is usable as a portion for receiving a connection establishing request. The portion 4011 may be configured to perform processing according to S300 of Fig. 5. Furthermore, the processor or processing circuitry or function 401 may include a sub-portion 4012 usable as a portion for processing the request. The portion 4012 may be configured to perform a processing according to S310 of Fig. 5. In addition, the processor or processing circuitry or function 401 may include a sub-portion 4013 usable as a portion for checking the presence of a dedicated network slice. The portion 4013 may be configured to perform a processing according to S320 and S330 of Fig. 5. Furthermore, the processor or processing circuitry or function 401 may include a sub-portion 4014 usable as a portion for sending the rerouting indication. The portion 4014 may be configured to perform a processing according to S340 of Fig. 5. Furthermore, the processor or processing circuitry or function 401 may include a sub-portion 4015 usable as a portion for conducting a processing for establishing a communication connection. The portion 4015 may be configured to perform a processing according to S350 of Fig. 5.

Fig. 8 shows a diagram of a network element or function acting as a core network control element for access and mobility management according to some examples of embodiments, e.g. the AMF 50 of Fig. 1 (or Fig. 9), which is configured to conduct a communication connection control procedure as described in connection with some of the examples of embodiments. It is to be noted that the network element or function, like the AMF 50 of Fig. 1 (or Fig. 9), may include further elements or functions besides those described herein below. Furthermore, even though reference is made to a network element or function, the element or function may be also another device or function having a similar task, such as a chipset, a chip, a module, an application etc., which can also be part of a network element or attached as a separate element to a network element, or the like. It should be understood that each block and any combination thereof may be implemented by various means or their combinations, such as hardware, software, firmware, one or more processors and/or circuitry. The network element 50 like the AMF shown in Fig. 8 may include a processing circuitry, a processing function, a control unit or a processor 501 , such as a CPU or the like, which is suitable for executing instructions given by programs or the like related to the communication connection control procedure. The processor 501 may include one or more processing portions or functions dedicated to specific processing as described below, or the processing may be run in a single processor or processing function. Portions for executing such specific processing may be also provided as discrete elements or within one or more further processors, processing functions or processing portions, such as in one physical processor like a CPU or in one or more physical or virtual entities, for example. Reference signs 502 and 503 denotes input/output (I/O) units or functions (interfaces) connected to the processor or processing function 501. The I/O units 502 may be used for communicating with the UE and RAN, as described in connection with Fig. 1 (or Fig. 9), for example. The I/O units 503 may be used for communicating with the CN control elements and functions, such as the SMF 40 and the NRF/NSSF, as described in connection with Fig. 1 (or Fig. 9), for example. The I/O units 502 and 503 may be a combined unit including communication equipment towards several entities, or may include a distributed structure with a plurality of different interfaces for different entities. Reference sign 504 denotes a memory usable, for example, for storing data and programs to be executed by the processor or processing function 501 and/or as a working storage of the processor or processing function 301. It is to be noted that the memory 504 may be implemented by using one or more memory portions of the same or different type of memory.

The processor or processing function 501 is configured to execute processing related to the above described communication connection control processing. In particular, the processor or processing circuitry or function 501 includes one or more of the following sub-portions. Sub-portion 5011 is a processing portion which is usable as a portion for receiving a connection establishing request. The portion 5011 may be configured to perform processing according to S400 of Fig. 6. Furthermore, the processor or processing circuitry or function 5010 may include a sub-portion 5012 usable as a portion for conducting a SMF selection and forwarding the request. The portion 5012 may be configured to perform a processing according to S410 or S440 of Fig. 6. In addition, the processor or processing circuitry or function 5010 may include a sub-portion 5013 usable as a portion for receiving and processing a rerouting indication. The portion 5013 may be configured to perform a processing according to S420 of Fig. 6. Moreover, the processor or processing circuitry or function 5010 may include a sub-portion 5014 usable as a portion for obtaining SMF information. The portion 5014 may be configured to perform a processing according to S430 of Fig. 6. Furthermore, the processor or processing circuitry or function 5010 may include a sub-portion 5015 usable as a portion for conducting a connection establishing processing. The portion 5015 may be configured to perform a processing according to S450 of Fig. 6.

As discussed above, a method is discussed which uses the access and mobility management function (AMF) for making a slice selection without NSSAI or other slice type information from the UE (e.g. LTE UE). When the LTE UE requests for new packet data network (PDN) connection in the initial attach it also requests to be connected to a specific APN which is decoded in the session management function (SMF). Based on the quality of service (QoS) or the access point name (APN) requested by the UE, SMF can ask slice type information from the unified data management (UDM). If there is a specific slice dedicated for this APN or specific QoS requirements, then the SMF delivers this information to the AMF. With the slice type information, the AMF can request an SMF for this specific slice type from the NRF and continue the attach procedure with the slice specific SMF, so that the AMF is forced to do an SMF reselection with slice type information received from the UDM.

It is to be noted that examples of embodiments of the invention are applicable to various different network configurations. In other words, the examples shown in the above described figures, which are used as a basis for the above discussed examples, are only illustrative and do not limit the present invention in any way. That is, additional further existing and proposed new functionalities available in a corresponding operating environment may be used in connection with examples of embodiments of the invention based on the principles defined.

According to a further example of embodiments, there is provided, for example, an apparatus for use by a core network control element or function configured to execute a communication connection related control for session management, the apparatus comprising means configured to receive a request for establishing a communication connection for a communication element, wherein the request includes session management information comprising at least one of an access point name and a quality of service requirement indication, means configured to process the request by decoding the session management information for obtaining the at least one of the access point name and the quality of service requirement indication, means configured to check whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, and means configured send, in case a specific network slice is dedicated for the obtained at least one of the access point name and the quality of service requirement indication, a rerouting indication to a communication network control element or function for access and mobility management, wherein the rerouting indication comprises network slice specific information and an indication to reroute the request for establishing the communication connection.

Furthermore, according to some other examples of embodiments, the above defined apparatus may further comprise means for conducting at least one of the processing defined in the above described methods, for example a method according that described in connection with Fig 5.

According to a further example of embodiments, there is provided, for example, an apparatus for use by a core network control element or function configured to execute a communication connection related control for access and mobility management, the apparatus comprising means configured to receive a request for establishing a communication connection for a communication element, wherein the request includes session management information comprising at least one of an access point name and a quality of service requirement indication, means configured to select a core network control element or function for session management serving the communication element, means configured to forward the request for establishing the communication connection to selected core network control element or function for session management, means configured to receive, from the selected core network control element or function for session management, a rerouting indication, wherein the rerouting indication comprises network slice specific information for a specific network slice dedicated for the at least one of the access point name and the quality of service requirement indication, and an indication to reroute the request for establishing the communication connection, means configured to obtain information indicating a new core network control element or function for session management related to a dedicated network slice, means configured forward the request for establishing the communication connection to the new core network control element or function for session management related to the dedicated network slice, and means configured to conduct a processing for establishing the communication connection with the new core network control element or function for session management related to the dedicated network slice.

Furthermore, according to some other examples of embodiments, the above defined apparatus may further comprise means for conducting at least one of the processing defined in the above described methods, for example a method according that described in connection with Fig 6.

It should be appreciated that

- an access technology via which traffic is transferred to and from an entity in the communication network may be any suitable present or future technology, such as WLAN (Wireless Local Access Network), WiMAX (Worldwide Interoperability for Microwave Access), LTE, LTE-A, 5G, Bluetooth, Infrared, and the like may be used; additionally, embodiments may also apply wired technologies, e.g. IP based access technologies like cable networks or fixed lines.

- embodiments suitable to be implemented as software code or portions of it and being run using a processor or processing function are software code independent and can be specified using any known or future developed programming language, such as a high- level programming language, such as objective-C, C, C++, C#, Java, Python, Javascript, other scripting languages etc., or a low-level programming language, such as a machine language, or an assembler.

- implementation of embodiments is hardware independent and may be implemented using any known or future developed hardware technology or any hybrids of these, such as a microprocessor or CPU (Central Processing Unit), MOS (Metal Oxide Semiconductor), CMOS (Complementary MOS), BiMOS (Bipolar MOS), BiCMOS (Bipolar CMOS), ECL (Emitter Coupled Logic), and/or TTL (Transistor-Transistor Logic).

- embodiments may be implemented as individual devices, apparatuses, units, means or functions, or in a distributed fashion, for example, one or more processors or processing functions may be used or shared in the processing, or one or more processing sections or processing portions may be used and shared in the processing, wherein one physical processor or more than one physical processor may be used for implementing one or more processing portions dedicated to specific processing as described, - an apparatus may be implemented by a semiconductor chip, a chipset, or a (hardware) module including such chip or chipset;

- embodiments may also be implemented as any combination of hardware and software, such as ASIC (Application Specific 1C (Integrated Circuit)) components, FPGA (Field- programmable Gate Arrays) or CPLD (Complex Programmable Logic Device) components or DSP (Digital Signal Processor) components.

- embodiments may also be implemented as computer program products, including a computer usable medium having a computer readable program code embodied therein, the computer readable program code adapted to execute a process as described in embodiments, wherein the computer usable medium may be a non-transitory medium.

Although the present invention has been described herein before with reference to particular embodiments thereof, the present invention is not limited thereto and various modifications can be made thereto.

Claims

1. An apparatus for use by a core network control element or function configured to execute a communication connection related control for session management, the apparatus comprising at least one processing circuitry, and

at least one memory for storing instructions to be executed by the processing circuitry, wherein the at least one memory and the instructions are configured to, with the at least one processing circuitry, cause the apparatus at least:

to receive a request for establishing a communication connection for a communication element, wherein the request includes session management information comprising at least one of an access point name and a quality of service requirement indication,

to process the request by decoding the session management information for obtaining the at least one of the access point name and the quality of service requirement indication,

to check whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, and

in case a specific network slice is dedicated for the obtained at least one of the access point name and the quality of service requirement indication, to send a rerouting indication to a communication network control element or function for access and mobility management, wherein the rerouting indication comprises network slice specific information and an indication to reroute the request for establishing the communication connection.

2. The apparatus according to claim 1 , wherein the request for establishing the communication connection comprises one of an initial attach request of the communication element, a packet data network connectivity request, and request for allocating a communication network resource.

3. The apparatus according to claim 1 or 2, wherein the at least one memory and the instructions are further configured to, with the at least one processing circuitry, cause the apparatus at least:

when checking whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, to send the obtained at least one of the access point name and the quality of service requirement indication to a control element or function for unified data management, and

to receive and process an answer from the control element or function for unified data management, wherein a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is determined to be present when the answer includes corresponding target slice information and subscriber information.

4. The apparatus according to any of claims 1 to 3, wherein the at least one memory and the instructions are further configured to, with the at least one processing circuitry, cause the apparatus at least:

to include, in the rerouting indication to be sent to the communication network control element or function for access and mobility management, the target slice information and the subscriber information.

5. The apparatus according to claim 3 or 4, wherein a communication with the control element or function for unified data management is executed by using one of

an update location related signaling, and

a signaling for providing subscriber information by using a signaling container.

6. The apparatus according to any of claims 1 to 5, wherein the at least one memory and the instructions are further configured to, with the at least one processing circuitry, cause the apparatus at least:

when checking whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present results in that no specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, to conduct a processing for establishing the communication connection according to the request.

7. The apparatus according to any of claims 1 to 6, further comprising at least one of the following:

the apparatus is included in a core network control element or function for session management for controlling a communication connection in a communication network of a first type, and

the communication element for which the communication connection is established is configured to communicate in a communication network of a second type being different to the first type.

8. A method for use in a core network control element or function configured to execute a communication connection related control for session management, the method comprising receiving a request for establishing a communication connection for a communication element, wherein the request includes session management information comprising at least one of an access point name and a quality of service requirement indication,

processing the request by decoding the session management information for obtaining the at least one of the access point name and the quality of service requirement indication,

checking whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, and

in case a specific network slice is dedicated for the obtained at least one of the access point name and the quality of service requirement indication, sending a rerouting indication to a communication network control element or function for access and mobility management, wherein the rerouting indication comprises network slice specific information and an indication to reroute the request for establishing the communication connection.

9. The method according to claim 8, wherein the request for establishing the communication connection comprises one of an initial attach request of the communication element, a packet data network connectivity request, and request for allocating a communication network resource.

10. The method according to claim 8 or 9, further comprising

when checking whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, sending the obtained at least one of the access point name and the quality of service requirement indication to a control element or function for unified data management, and

receiving and processing an answer from the control element or function for unified data management,

wherein a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is determined to be present when the answer includes corresponding target slice information and subscriber information.

11. The method according to any of claims 8 to 10, further comprising

including, in the rerouting indication to be sent to the communication network control element or function for access and mobility management, the target slice information and the subscriber information.

12. The method according to claim 10 or 11 , wherein a communication with the control element or function for unified data management is executed by using one of

an update location related signaling, and a signaling for providing subscriber information by using a signaling container.

13. The method according to any of claims 8 to 12, further comprising

when checking whether a specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present results in that no specific network slice dedicated for the obtained at least one of the access point name and the quality of service requirement indication is present, conducting a processing for establishing the communication connection according to the request.

14. The method according to any of claims 8 to 13, further comprising at least one of the following:

the method is implemented in a core network control element or function for session management for controlling a communication connection in a communication network of a first type, and

the communication element for which the communication connection is established communicates in a communication network of a second type being different to the first type.

15. An apparatus for use by a core network control element or function configured to execute a communication connection related control for access and mobility management, the apparatus comprising

at least one processing circuitry, and

to select a core network control element or function for session management serving the communication element,

to forward the request for establishing the communication connection to selected core network control element or function for session management,

to receive, from the selected core network control element or function for session management, a rerouting indication, wherein the rerouting indication comprises network slice specific information for a specific network slice dedicated for the at least one of the access point name and the quality of service requirement indication, and an indication to reroute the request for establishing the communication connection, to obtain information indicating a new core network control element or function for session management related to a dedicated network slice,

to forward the request for establishing the communication connection to the new core network control element or function for session management related to the dedicated network slice, and

to conduct a processing for establishing the communication connection with the new core network control element or function for session management related to the dedicated network slice.

16. The apparatus according to claim 15, wherein the request for establishing the communication connection comprises one of an initial attach request of the communication element, a packet data network connectivity request, and request for allocating a communication network resource.

17. The apparatus according to claim 15 or 16, wherein the at least one memory and the instructions are further configured to, with the at least one processing circuitry, cause the apparatus at least:

when the rerouting indication is not received, to conduct a processing for establishing the communication connection with the serving core network control element or function for session management.

18. The apparatus according to any of claims 15 to 17, wherein the at least one memory and the instructions are further configured to, with the at least one processing circuitry, cause the apparatus at least:

to select, as the core network control element or function for session management serving the communication element, one of a default core network control element or function for session management and a previously determined core network control element or function for session management related to a network slice.

19. The apparatus according to any of claims 15 to 18, wherein the rerouting indication comprises target slice information and subscriber information of the communication element.

20. The apparatus according to claim 19, wherein the at least one memory and the instructions are further configured to, with the at least one processing circuitry, cause the apparatus at least:

when obtaining the information indicating the new core network control element or function for session management related to the dedicated network slice, to send the target slice information to a core network control element or function for providing network function related information, and

to receive, from the core network control element or function for providing network function related information, and process slice specific session management function information indicating the new core network control element or function for session management related to the dedicated network slice.

21. The apparatus according to any of claims 15 to 20, further comprising at least one of the following:

the apparatus is included in a core network control element or function for access and mobility management for controlling a communication connection in a communication network of a first type, and

22. A method for use in a core network control element or function configured to execute a communication connection related control for access and mobility management, the method comprising

receiving a request for establishing a communication connection for a communication element, wherein the request includes session management information comprising at least one of an access point name and a quality of service requirement indication,

selecting a core network control element or function for session management serving the communication element,

forwarding the request for establishing the communication connection to selected core network control element or function for session management,

receiving, from the selected core network control element or function for session management, a rerouting indication, wherein the rerouting indication comprises network slice specific information for a specific network slice dedicated for the at least one of the access point name and the quality of service requirement indication, and an indication to reroute the request for establishing the communication connection,

obtaining information indicating a new core network control element or function for session management related to a dedicated network slice,

forwarding the request for establishing the communication connection to the new core network control element or function for session management related to the dedicated network slice, and conducting a processing for establishing the communication connection with the new core network control element or function for session management related to the dedicated network slice.

23. The method according to claim 22, wherein the request for establishing the communication connection comprises one of an initial attach request of the communication element, a packet data network connectivity request, and request for allocating a communication network resource.

24. The method according to claim 22 or 23, further comprising

when the rerouting indication is not received, conducting a processing for establishing the communication connection with the serving core network control element or function for session management.

25. The method according to any of claims 22 to 24, further comprising

selecting, as the core network control element or function for session management serving the communication element, one of a default core network control element or function for session management and a previously determined core network control element or function for session management related to a network slice.

26. The method according to any of claims 22 to 25, wherein the rerouting indication comprises target slice information and subscriber information of the communication element.

27. The method according to claim 26, further comprising

when obtaining the information indicating the new core network control element or function for session management related to the dedicated network slice, sending the target slice information to a core network control element or function for providing network function related information, and

receiving, from the core network control element or function for providing network function related information, and processing slice specific session management function information indicating the new core network control element or function for session management related to the dedicated network slice.

28. The method according to any of claims 22 to 27, further comprising at least one of the following: the method is implemented in a core network control element or function for access and mobility management for controlling a communication connection in a communication network of a first type, and

29. A computer program product for a computer, including software code portions for performing the steps of any of claims 7 to 14 or any of claims 22 to 28 when said product is run on the computer.

30. The computer program product according to claim 45, wherein

the computer program product includes a computer-readable medium on which said software code portions are stored, and/or

the computer program product is directly loadable into the internal memory of the computer and/or transmittable via a network by means of at least one of upload, download and push procedures.