Method, apparatus and computer program

Abstract

A network function apparatus, the apparatus comprising means for sending a message to a radio access network node serving a user equipment, the message comprising a non-access stratum container and an indication outside the non-access stratum container that a network slice for the user equipment has been replaced by an alternative network slice.

Description

TECHNICAL FIELD

[0001] The present application relates to a method, apparatus, system and computer program. BACKGROUND

[0002] A communication system can be seen as a facility that enables communication sessions between two or more entities such as user terminals, base stations and / or other nodes by providing carriers for carrying the traffic over the communication paths involved. A communication system can be provided for example by means of a communication network and one or more compatible communication devices. The communication sessions can comprise, for example, communication of data for carrying communications such as voice, video, electronic mail (email), text message, multimedia and / or content data, etc. Non-limiting examples of services provided include two-way or multi-way calls, data communication or multimedia services, and access to a data network system, such as the Internet.

[0003] In a wireless communication system the communication sessions between at least two stations occur at least partly over a wireless link. Examples of wireless systems include public land mobile networks (PLMN), satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). Some wireless systems can be divided into cells, and are therefore often referred to as cellular systems.

[0004] A user can access the communication system by means of an appropriate communication device or terminal. The user's communication device can be referred to as user equipment (UE) or user apparatus. The communication device is provided with an appropriate signal receiving and transmitting apparatus for enabling communication, for example communication with a base station of a communication network or directly with another user's communication device. The communication device can access the carriers provided by stations, for example base stations of cells, and transmit and / or receive communication on the carriers.

[0005] The communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do, and how that should be implemented. The communication protocols and / or parameters used for the connection are also typically defined. One example of a communication system is the UTRAN (3G radio). Other examples of communication systems are the Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), Long Term Evolution (LTE) and so-called 5G or New Radio (NR) networks. NR is being standardized by the Third Generation Partnership Project (3GPP). SUMMARY

[0006] According to a first aspect, there is provided a method performed by a network function, the method comprising: sending, to a radio access network node serving a user equipment, a message comprising: a non-access stratum container, and outside of the non-access stratum container, an indication that a network slice for the user equipment has been replaced by an alternative network slice.

[0007] According to some examples, the method comprises generating, by the network function, a message comprising: a non-access stratum container, and an indication outside the non-access stratum container that a network slice for the user equipment has been replaced by an alternative network slice. In some examples, the message can be generated in response to receiving an indication that the network slice for the user equipment has been replaced by the alternative network slice. Alternatively, the message can be generated by the network function in response to receiving a message indicating a modification of a data session.

[0008] According to some examples, the method comprises sending, to the second radio access network node, an indication that a service area of the network slice can be changed to include a service area of the alternative network slice when the network slice for the user equipment is replaced by the alternative network slice.

[0009] According to some examples, the method comprises sending, to the radio access network node, an indication that a service area of the network slice can be changed to include a service area of the alternative network slice when the network slice for the user equipment is replaced by the alternative network slice.

[0010] According to some examples, the indication sent outside the non-access stratum container comprises: an identifier of the network slice, and an identifier of the alternative network slice.

[0011] According to some examples, the network function comprises a network function for managing mobility of user equipment in the network, and the method comprises sending, to a session management function, a message indicating that the network slice has been replaced by an alternative network slice for the user equipment, enabling the session management function to perform at least one of: replacing at least one data session for the network slice for the user equipment with the alternative network slice, and replacing at least one data session for the network slice for the user equipment with at least one data session for the alternative network slice; wherein sending the message comprising the non-access stratum container, and the indication outside the non-access stratum container that the network slice for the user equipment has been replaced by the alternative network slice comprises forwarding an indication received from the session management function that the network slice has been replaced by the alternative network slice.

[0012] According to some examples, the second radio access network supports the alternative network slice but not the network slice, and based on the indication that the service area can be changed to include a service area of the alternative network slice when the network slice for the user equipment is replaced by the alternative network slice, the second radio access network node accepts handover of the radio access network node from at least one data session of the alternative network slice indicated as a replacement for the network slice.

[0013] According to some examples, the method includes: receiving a mobility registration update from a user equipment, the mobility registration update including: an indication of whether a data session for a network slice of the user equipment should be removed or maintained, the network slice being replaced by an alternative network slice; and removing or maintaining the data session based on the mobility registration update.

[0014] According to some examples, a network slice becomes available after a period of unavailability, and the method includes sending an indication that the network slice is available to at least one of a radio access network node and a second radio access network node.

[0015] According to a second aspect, a network function apparatus is provided, comprising: a component for sending a message to a radio access network node serving a user equipment, the message including: a non-access stratum container, and an indication outside the non-access stratum container that a network slice of the user equipment has been replaced by a candidate network slice.

[0016] According to some examples, the method includes generating a message via a network function, the message including a non-access stratum container and an indication that a network slice for a user equipment outside the non-access stratum container has been replaced by a candidate network slice.

[0017] According to some examples, the network function apparatus includes a network function for managing mobility. An example of such a network function could be an Access and Mobility Management Function (AMF). In response to receiving a message indicating a modification to a data session, the network function may generate a message including a non-access stratum container and, outside of that container, an indication that a network slice for the user equipment has been replaced by an alternative network slice.

[0018] Based on some examples, messages indicating modifications to a data session can be received from network functions used to manage data sessions.

[0019] According to some examples, the network function apparatus includes a network function for managing data sessions. An example of such a network function could be a Session Management Function (SMF). In some examples, a message can be generated in response to receiving an indication that a network slice for a user equipment has been replaced with a candidate network slice. This message includes a non-access stratum container and an indication, outside of the non-access stratum container, that the network slice for the user equipment has been replaced by the candidate network slice.

[0020] Based on some examples, an indication can be received from network functions used to manage mobility that a network slice for a user device has been replaced by an alternative network slice.

[0021] According to some examples, the apparatus includes a component for transmitting to a second radio access network node an indication that the service area of ​​a network slice can be changed to include the service area of ​​the alternative network slice when a network slice for a user equipment is replaced by an alternative network slice.

[0022] According to some examples, the apparatus includes a component for transmitting to a radio access network node an indication that the service area of ​​a network slice can be changed to include the service area of ​​the alternative network slice when a network slice for a user equipment is replaced by an alternative network slice.

[0023] According to some examples, the indications sent outside the non-access stratum container include: the identifier of the network slice, and the identifier of the alternative network slice.

[0024] According to some examples, the network function apparatus includes: a network function for managing the mobility of user equipment in a network, and the apparatus includes: a component for sending a message to a session management function, the message indicating that a network slice has been replaced by a candidate network slice for the user equipment, such that the session management function is able to perform at least one of the following: replacing at least one data session of the network slice for the user equipment with the candidate network slice, and replacing at least one data session of the network slice for the user equipment with at least one data session of the candidate network slice; wherein sending the message including a non-access stratum container and an indication outside the non-access stratum container that the network slice for the user equipment has been replaced by a candidate network slice includes: forwarding the indication received from the session management function that the network slice has been replaced by a candidate network slice.

[0025] According to some examples, the second radio access network supports alternative network slices but does not support network slices, wherein based on an indication that the service area can be changed to include the service area of ​​the alternative network slice when the network slice used for the user equipment is replaced by an alternative network slice, the second radio access network node accepts the handover of the radio access network node from at least one data session of the alternative network slice, the alternative network slice being indicated as the replacement of the network slice.

[0026] According to some examples, the apparatus includes: components for receiving a mobility registration update from a user equipment, the mobility registration update including: an indication for whether a data session of a network slice of the user equipment should be removed or maintained, the network slice being replaced by an alternative network slice; and components for removing or maintaining the data session based on the mobility registration update.

[0027] According to some examples, the apparatus includes: a network slice becomes available after a period of unavailability, and the apparatus includes: a component for sending an indication that the network slice is available to at least one of a radio access network node and a second radio access network node.

[0028] According to a third aspect, an apparatus is provided, comprising: at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, cause the apparatus to at least: send a message to a radio access network node serving a user equipment, the message including: a non-access stratum container, and an indication, outside the non-access stratum container, that a network slice for the user equipment has been replaced by an alternative network slice.

[0029] According to some examples, the at least one memory and the computer program code are configured, together with the at least one processor, such that the apparatus at least performs: generating a message via a network function, the message including: a non-access stratum container, and an indication that a network slice for the user equipment outside the non-access stratum container has been replaced by a candidate network slice. In some examples, the message may be generated in response to receiving an indication that a network slice for the user equipment has been replaced with a candidate network slice. Alternatively, the message may be generated via a network function in response to receiving a message indicating a modification of a data session.

[0030] According to some examples, the at least one memory and the computer program code are configured together with the at least one processor to cause the device to at least perform: sending an indication to a second radio access network node that the service area of ​​a network slice can be changed to include the service area of ​​the alternative network slice when the network slice for the user equipment is replaced by an alternative network slice.

[0031] According to some examples, the at least one memory and the computer program code are configured together with the at least one processor to cause the device to at least perform: sending an indication to a radio access network node that the service area of ​​a network slice can be changed to include the service area of ​​the alternative network slice when the network slice used for a user equipment is replaced by an alternative network slice.

[0032] According to some examples, the indications sent outside the non-access stratum container include: the identifier of the network slice, and the identifier of the alternative network slice.

[0033] According to some examples, the network function apparatus includes: a network function for managing the mobility of user equipment in a network, wherein the at least one memory and the computer program code are configured together with the at least one processor such that the apparatus at least performs: sending a message to a session management function indicating that a network slice has been replaced by a candidate network slice for the user equipment, such that the session management function is able to perform at least one of the following: replacing at least one data session of the network slice for the user equipment with the candidate network slice, and replacing at least one data session of the network slice for the user equipment with at least one data session of the candidate network slice; wherein sending the message including a non-access stratum container and an indication outside the non-access stratum container that the network slice for the user equipment has been replaced by a candidate network slice includes: forwarding the indication received from the session management function that the network slice has been replaced by a candidate network slice.

[0034] According to some examples, the second radio access network supports alternative network slices but does not support network slices, wherein based on an indication that the service area can be changed to include the service area of ​​the alternative network slice when the network slice used for the user equipment is replaced by an alternative network slice, the second radio access network node accepts the handover of the radio access network node from at least one data session of the alternative network slice, the alternative network slice being indicated as the replacement of the network slice.

[0035] According to some examples, the at least one memory and the computer program code are configured together with the at least one processor such that the apparatus at least performs: receiving a mobility registration update from a user equipment, the mobility registration update including: an indication of whether a data session for a network slice of the user equipment should be removed or maintained, the network slice being replaced by an alternative network slice; and removing or maintaining the data session based on the mobility registration update.

[0036] According to some examples, the at least one memory and the computer program code are configured together with the at least one processor such that the device performs at least: sending an indication that a network slice is available to at least one of the radio access network node and the second radio access network node.

[0037] According to a fourth aspect, a network function apparatus is provided, comprising: a circuit system for: sending a message to a radio access network node serving a user equipment, the message including: a non-access stratum container, and an indication outside the non-access stratum container that a network slice for the user equipment has been replaced by a candidate network slice.

[0038] According to a fifth aspect, a computer program is provided, including instructions for causing a device to perform at least the following: sending a message to a radio access network node serving a user equipment, the message including: a non-access stratum container, and an indication outside the non-access stratum container that a network slice for the user equipment has been replaced by an alternative network slice.

[0039] According to a sixth aspect, a computer program is provided, including instructions stored thereon, the instructions being configured to cause a device to perform at least the following: sending a message to a radio access network node serving a user equipment, the message including: a non-access stratum container, and an indication outside the non-access stratum container that a network slice for the user equipment has been replaced by an alternative network slice.

[0040] According to a seventh aspect, a non-transitory computer-readable medium is provided, including program instructions for causing a device to perform at least the following: sending a message to a radio access network node serving a user equipment, the message including: a non-access stratum container, and an indication outside the non-access stratum container that a network slice for the user equipment has been replaced by an alternative network slice.

[0041] According to an eighth aspect, a non-transitory computer-readable medium is provided, including program instructions stored thereon for performing at least the following: sending a message to a radio access network node serving a user equipment, the message including: a non-access stratum container, and an indication outside the non-access stratum container that a network slice for the user equipment has been replaced by an alternative network slice.

[0042] According to a ninth aspect, a method is provided performed by a radio access network node, the method comprising: determining that a data session for a user equipment initially belongs to a network slice that has been replaced by a candidate network slice; and based on the determination, accepting or rejecting a handover of the data session for the user equipment.

[0043] According to some examples, the method includes: receiving from a second radio access network node an indication that a data unit session for a user equipment initially belongs to a network slice that has been replaced by a candidate network slice, wherein the determination is based on the received indication.

[0044] According to some examples, the radio access network node does not support network slicing, and the switching is performed from a second radio access network node that supports network slicing and alternative network slicing, wherein the method includes: supporting alternative network slicing.

[0045] According to some examples, the method includes: receiving from a network function an indication that the service area of ​​a network slice can be changed to include the service area of ​​the alternative network slice when a network slice used for a user equipment is replaced by a candidate network slice, wherein the determination is based on the received indication.

[0046] According to some examples, when a user slice is congested or undergoing maintenance, the network slice used for the user equipment is replaced with an alternative network slice.

[0047] According to some examples, after a network slice used for a user equipment becomes available again when the network slice is unavailable and is replaced by an alternative network slice, the method includes: receiving an indication that the network slice has become available from a network function used to manage the mobility of user equipment in the network; and accepting or rejecting a subsequent handover based on the indication that the network slice has become available.

[0048] According to a tenth aspect, a radio access network apparatus is provided, comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured together with the at least one processor such that the apparatus at least performs: receiving from a second radio access network node an indication that a data unit session for a user equipment initially belongs to a network slice that has been replaced by a candidate network slice, wherein the determination is based on the received indication.

[0049] According to some examples, the radio access network device includes a target node.

[0050] According to some examples, the radio access network device does not support network slicing and switches from a second radio access network node that supports network slicing and alternative network slicing, and the at least one memory and the computer program code are configured together with the at least one processor such that the device at least performs: support for alternative network slicing.

[0051] According to some examples, the at least one memory and the computer program code are configured together with the at least one processor such that the device at least performs: receiving from a network function an indication that the service area of ​​a network slice can be changed to include the service area of ​​the alternative network slice when a network slice for a user equipment is replaced by an alternative network slice, wherein the determination is based on the received indication.

[0052] According to some examples, when a user slice is congested or undergoing maintenance, the network slice used for the user equipment is replaced with an alternative network slice.

[0053] According to some examples, after a network slice used for a user equipment is replaced with an alternative network slice when the network slice is unavailable, the network slice becomes available again, and the at least one memory and the computer program code are configured together with the at least one processor to cause the apparatus to at least perform: receiving an indication from a network function for managing the mobility of user equipment in the network that the network slice has become available; and accepting or rejecting a subsequent handover based on the indication that the network slice has become available.

[0054] According to the eleventh aspect, a radio access network apparatus is provided, comprising: a component for determining whether a data session for a user equipment initially belongs to a network slice that has been replaced by a candidate network slice; and a component for accepting or rejecting a handover of the data session for the user equipment based on the determination.

[0055] According to some examples, the apparatus includes: a component for receiving from a second radio access network node an indication that a data unit session for a user equipment initially belongs to a network slice that has been replaced by an alternative network slice, wherein the determination is based on the received indication.

[0056] According to some examples, the device does not support network slicing, and the switching is performed from a second radio access network node that supports network slicing and alternative network slicing, and the device includes: components for supporting alternative network slicing.

[0057] According to some examples, the apparatus includes: a component for receiving from a network function an indication that the service area of ​​a network slice can be changed to include the service area of ​​the alternative network slice when a network slice for a user equipment is replaced by an alternative network slice, wherein the determination is based on the received indication.

[0058] According to some examples, when a user slice is congested or undergoing maintenance, the network slice used for the user equipment is replaced with an alternative network slice.

[0059] According to some examples, after a network slice used for a user equipment becomes available again when the network slice is unavailable and is replaced by an alternative network slice, the apparatus includes: components for receiving an indication from a network function for managing the mobility of user equipment in the network that the network slice has become available; and components for accepting or rejecting a subsequent handover based on the indication that the network slice has become available.

[0060] According to a twelfth aspect, an apparatus is provided, comprising: a circuit system configured to: determine that a data session for a user equipment initially belongs to a network slice that has been replaced by a candidate network slice; and based on the determination, accept or reject a handover of the data session for the user equipment.

[0061] According to a thirteenth aspect, a computer program is provided, including instructions for causing a device to perform at least the following: determining that a data session for a user equipment initially belongs to a network slice that has been replaced by a candidate network slice; and based on the determination, accepting or rejecting a handover of the data session for the user equipment.

[0062] According to the fourteenth aspect, a computer program is provided, including instructions stored thereon, the instructions being configured to perform at least the following: determining that a data session for a user equipment initially belongs to a network slice that has been replaced by an alternative network slice; and based on the determination, accepting or rejecting a handover of the data session for the user equipment.

[0063] According to the fifteenth aspect, a non-transitory computer-readable medium is provided, including program instructions for causing a device to perform at least the following: determining that a data session for a user equipment initially belongs to a network slice that has been replaced by a candidate network slice; and based on the determination, accepting or rejecting a handover of the data session for the user equipment.

[0064] According to the sixteenth aspect, a non-transitory computer-readable medium is provided, including program instructions stored thereon for performing at least the following: determining that a data session for a user equipment initially belongs to a network slice that has been replaced by an alternative network slice; and based on the determination, accepting or rejecting a handover of the data session for the user equipment.

[0065] According to the seventeenth aspect, a method performed by a user equipment is provided, the method comprising: sending an indication to a network function for managing the mobility of the user equipment, the indication indicating whether a data session for a network slice of the user equipment, which is being replaced by an alternative network slice, should be removed or maintained by the network function.

[0066] According to some examples, the instruction is sent via a mobility registration update.

[0067] According to some examples, the method includes receiving from a radio access network node serving a user equipment an indication that a network slice for the user equipment has been replaced by a candidate network slice.

[0068] According to the eighteenth aspect, a user equipment apparatus is provided, comprising: a component for sending an instruction to a network function for managing the mobility of the user equipment, the instruction indicating whether a data session of a network slice for the user equipment, which is being replaced by an alternative network slice, should be removed or maintained by the network function.

[0069] According to some examples, the instruction is sent via a mobility registration update.

[0070] According to some examples, the apparatus includes: a component for receiving from a radio access network node serving a user equipment an indication that a network slice for the user equipment has been replaced by an alternative network slice.

[0071] According to a nineteenth aspect, an apparatus is provided, comprising: at least one processor and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the apparatus to at least: send an instruction to a network function for managing the mobility of a user equipment, the instruction indicating whether a data session for a network slice of the user equipment, which is being replaced by an alternative network slice, should be removed or maintained by the network function.

[0072] According to some examples, the instruction is sent via a mobility registration update.

[0073] According to some examples, the at least one memory and the computer program code are configured together with the at least one processor to cause the device to at least perform: receiving from a radio access network node serving a user equipment an indication that a network slice for the user equipment has been replaced by an alternative network slice.

[0074] According to a twentieth aspect, an apparatus is provided, comprising: a circuit system configured to: send an indication to a network function for managing the mobility of a user equipment, the indication indicating whether a data session for a network slice of the user equipment, which is being replaced by an alternative network slice, should be removed or maintained by the network function.

[0075] According to the twenty-first aspect, a computer program is provided, including instructions for causing a device to perform at least the following: sending an instruction to a network function for managing the mobility of a user equipment, the instruction indicating whether a data session for a network slice of the user equipment, which is being replaced by an alternative network slice, should be removed or maintained by the network function.

[0076] According to the twenty-second aspect, a computer program is provided, including instructions stored thereon, the instructions being used to cause the device to perform at least the following: sending an instruction to a network function for managing the mobility of a user equipment, the instruction indicating whether a data session for a network slice of the user equipment, which is being replaced by an alternative network slice, should be removed or maintained by the network function.

[0077] According to the twenty-third aspect, a non-transitory computer-readable medium is provided, including program instructions for causing a device to perform at least the following: sending an instruction to a network function for managing the mobility of a user equipment, the instruction indicating whether a data session for a network slice of the user equipment, which is being replaced by an alternative network slice, should be removed or maintained by the network function.

[0078] According to the twenty-fourth aspect, a non-transitory computer-readable medium is provided, including program instructions stored thereon, the program instructions being configured to cause the device to perform at least the following: sending an instruction to a network function for managing the mobility of a user equipment, the instruction indicating whether a data session for a network slice of the user equipment, which has been replaced by an alternative network slice, should be removed or maintained by the network function.

[0079] According to the twenty-fifth aspect, a method performed by a radio access network node is provided, the method comprising: receiving an indication that a network slice for a user equipment has been replaced by a candidate network slice; and sending an indication that a network slice for a user equipment has been replaced by a candidate network slice to a target radio access network node during a handover preparation process for the user equipment.

[0080] According to some examples, instructions sent outside of the non-access stratum container include: the identifier of the network slice, and the identifier of the alternative network slice.

[0081] According to some examples, the method includes: performing a determination that the service area can be changed to include the alternative network slice when the network slice for the user equipment is replaced by the alternative network slice; and at least one of the following: based on the determination, sending an indication to the target radio access network node that the network slice for the user equipment has been replaced by the alternative network slice; and based on the determination, triggering handover preparation.

[0082] According to some examples, the core network node receives an indication from an NGAP (Next Generation Application Protocol) PDU session resource establishment request or PDU session resource modification request message that the network slice for the user equipment has been replaced by a candidate network slice.

[0083] According to some examples, when a network slice used for a user equipment is replaced by a candidate network slice, the determination of whether the service area can be changed to include the service area of ​​the candidate network slice is based on an instruction received from the core network node.

[0084] According to some examples, this determination is based on policy instructions received from 5GC or network configuration.

[0085] According to a twenty-sixth aspect, an apparatus is provided, comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured together with the at least one processor such that the apparatus at least performs: receiving an indication that a network slice for a user equipment has been replaced by a candidate network slice; and sending an indication that a network slice for a user equipment has been replaced by a candidate network slice to a target radio access network node during a handover preparation process for the user equipment.

[0086] According to some examples, instructions sent outside of the non-access stratum container include: the identifier of the network slice, and the identifier of the alternative network slice.

[0087] According to some examples, the at least one memory and the computer program code are configured together with the at least one processor to cause the device to perform at least: determine that when the network slice for the user equipment is replaced by a candidate network slice, the service area can be changed to a service area including the candidate network slice; and at least one of the following: based on the determination, send an indication to the target radio access network node that the network slice for the user equipment has been replaced by the candidate network slice; and based on the determination, trigger handover preparation.

[0088] According to some examples, the core network node receives an indication from an NGAP (Next Generation Application Protocol) PDU session resource establishment request or PDU session resource modification request message that the network slice for the user equipment has been replaced by a candidate network slice.

[0089] According to some examples, when a network slice used for a user equipment is replaced by a candidate network slice, the determination of whether the service area can be changed to include the service area of ​​the candidate network slice is based on an instruction received from the core network node.

[0090] According to some examples, this determination is based on policy instructions received from 5GC or network configuration.

[0091] According to the twenty-seventh aspect, a radio access network node apparatus is provided, comprising: a component for receiving an indication that a network slice for a user equipment has been replaced by a candidate network slice; and a component for transmitting an indication that a network slice for a user equipment has been replaced by a candidate network slice to a target radio access network node during a handover preparation process for the user equipment.

[0092] According to some examples, the radio access network node includes a source node.

[0093] According to some examples, instructions sent outside of the non-access stratum container include: the identifier of the network slice, and the identifier of the alternative network slice.

[0094] According to some examples, the apparatus includes: components for performing a determination that a service area can be changed to include a service area of ​​the alternative network slice when a network slice for a user equipment is replaced by an alternative network slice; and at least one of the following: components for sending an indication to a target radio access network node, based on the determination, that the network slice for the user equipment has been replaced by the alternative network slice; and components for triggering handover preparation based on the determination.

[0095] According to some examples, the core network node receives an indication from an NGAP (Next Generation Application Protocol) PDU session resource establishment request or PDU session resource modification request message that the network slice for the user equipment has been replaced by a candidate network slice.

[0096] According to some examples, when a network slice used for a user equipment is replaced by a candidate network slice, the determination of whether the service area can be changed to include the service area of ​​the candidate network slice is based on an instruction received from the core network node.

[0097] According to some examples, this determination is based on policy instructions received from 5GC or network configuration.

[0098] According to the twenty-eighth aspect, an apparatus is provided, comprising: a circuit system configured to: receive an indication that a network slice for a user equipment has been replaced by a candidate network slice; and transmit to a target radio access network node during a handover preparation process for the user equipment the indication that a network slice for the user equipment has been replaced by a candidate network slice.

[0099] According to the twenty-ninth aspect, a computer program is provided, including instructions for causing a device to perform at least the following: receiving an indication that a network slice for a user equipment has been replaced by a candidate network slice; and sending an indication to a target radio access network node during a handover preparation process for the user equipment that a network slice for the user equipment has been replaced by a candidate network slice.

[0100] According to a thirtieth aspect, a computer program is provided, including instructions stored thereon, the instructions being configured to cause a device to perform at least the following: receiving an indication that a network slice for a user equipment has been replaced by a candidate network slice; and sending an indication to a target radio access network node during a handover preparation process for the user equipment that a network slice for the user equipment has been replaced by a candidate network slice.

[0101] According to the thirty-first aspect, a non-transitory computer-readable medium is provided, including program instructions for causing a device to perform at least the following: receiving an indication that a network slice for a user equipment has been replaced by a candidate network slice; and sending an indication to a target radio access network node during a handover preparation process for the user equipment that a network slice for the user equipment has been replaced by a candidate network slice.

[0102] According to the thirty-second aspect, a non-transitory computer-readable medium is provided, including program instructions stored thereon, the program instructions being configured to cause a device to perform at least the following: receiving an indication that a network slice for a user equipment has been replaced by a candidate network slice; and sending an indication to a target radio access network node during a handover preparation process for the user equipment that a network slice for the user equipment has been replaced by a candidate network slice.

[0103] According to one aspect, a non-transitory computer-readable medium is provided, comprising program instructions that, when executed by a device, cause the device to perform at least the method according to any one of the preceding aspects.

[0104] In the foregoing, many different embodiments have been described. It should be understood that other embodiments may be provided by combining any two or more of the above embodiments. Attached Figure Description

[0105] The embodiments will now be described by way of example only with reference to the accompanying drawings, in which:

[0106] Figure 1 A schematic diagram of a network system according to some example embodiments is shown;

[0107] Figure 2 An example message stream is shown;

[0108] Figure 3 An example message stream is shown;

[0109] Figure 4 A schematic diagram of a control device according to some example embodiments is shown;

[0110] Figure 5 A schematic diagram of an apparatus according to some example embodiments is shown;

[0111] Figure 6 An example message stream is shown;

[0112] Figure 7 An example message stream is shown;

[0113] Figure 8 An example message stream is shown;

[0114] Figure 9 An example message stream is shown;

[0115] Figure 10 A schematic diagram of a non-volatile storage medium for storing instructions is shown. These instructions, when executed by the processor, allow the processor to perform... Figures 2 to 3 Or one or more steps of method 6 to 9. Detailed Implementation

[0116] Certain embodiments will now be explained with reference to mobile communication devices capable of communicating via wireless cellular systems and mobile communication systems serving such mobile communication devices. Before explaining the exemplary embodiments in detail, refer to... Figure 1 A brief explanation of some general principles of wireless communication systems, their access systems, and mobile communication devices is provided to aid in understanding the technologies underlying the examples described.

[0117] Figure 1 A schematic diagram of a 5G system (5GS) 100 is shown. The 5GS 100 may consist of a terminal or user equipment (UE) 102, a 5G radio access network (5GRAN) 106 or a next-generation radio access network (NG-RAN), a 5G core network (5GC) 104, at least one application function (AF) 108, and at least one data network (DN) 110.

[0118] 5G-RAN 106 may include: one or more gNodeBs (GNBs), or one or more gNodeB (GNB) distributed unit functions connected to one or more gNodeB (GNB) centralized unit functions.

[0119] 5GC 104 may include the following entities: Data Slice Selection Function (NSSF); Network Open Function (NEF) 122; Network Repository Function (NRF); Policy Control Function (PCF); Unified Data Management (UDM) 118; Application Function (AF); Authentication Server Function (AUSF) 116; Access and Mobility Management Function (AMF) 112; and Session Management Function (SMF) 114.

[0120] Network slicing can include logical networks that provide specific network capabilities and characteristics, and consists of RAN, CN, and transport networks.

[0121] Network slices can be identified using Single Network Slice Selection Auxiliary Information (S-NSSAI). Network slice selection auxiliary information (NSSAI) can include at least one S-NSSAI.

[0122] When a UE uses a network slice, issues such as the network slice entering maintenance or congestion may occur. In some examples, this may happen on the CN side. In such cases, providing alternative network slices for the UE to use may be useful. Of course, there may be other situations where providing alternative network slices to the UE is useful. In some examples, alternative network slices can be provided by network function devices (e.g., AMF) used to manage the mobility of user equipment in the network. In some examples, this can be done via pre-configuration by Operation, Management and Maintenance (OAM) or via a decision made with other network functions (NFs) such as PCF or NSSF.

[0123] In some examples, network function apparatuses used to manage the mobility of user equipment in the network determine alternative S-NSSAIs (i.e., S-NSSAIs among the allowed NSSAIs of the UE) for UEs that have registered S-NSSAIs.

[0124] Based on some examples, if a UE indicates support for network slice replacement features during UE registration and some S-NSSAIs need to be replaced, the AMF provides the UE with allowed NSSAIs and / or alternative S-NSSAIs (if not already included) from the configured NSSAIs in the UE configuration update message by providing the UE with a mapping from old S-NSSAIs to alternative S-NSSAIs, and mappings between (multiple) S-NSSAIs to (multiple) alternative S-NSSAIs. The UE may include alternative S-NSSAIs as part of the requested NSSAIs in the RRC connection establishment used for AMF selection in NG-RAN.

[0125] Network slice replacement is discussed in 3GPP Change Request (CR) S2-2301602 and TR 23.700-41 in 3GPP Release 18, SA2.

[0126] When the original network slice in the CN is under maintenance or congested, it may be useful to provide the UE with an alternative slice for the UE to use. However, when the UE is configured with an alternative slice and the UE has a data session (e.g., a PDU session) mapped to the alternative network slice, it may be unclear whether the service area of ​​the original slice or the alternative slice is being used.

[0127] In such ambiguous situations, for example, a gNB that does not support the original slice but supports the alternative slice cannot determine whether to accept / reject data sessions on the alternative slice during handover. This can lead the target RAN node to make incorrect decisions during handover when accepting or rejecting data sessions. Furthermore, in such scenarios, the UE may intend to retain / remove PDU sessions mapped to the alternative slice based on its own preferences. For example, the current utilization of resources on the UE side can influence the UE's preferences. The determination of whether the quality of service can be achieved after replacing the PDU session on the alternative slice can also influence the UE's preferences.

[0128] Furthermore, the RAN node may not be aware of which data sessions in the candidate slice are local data sessions (not mapped from different network slices) and which are data sessions from different slices mapped to the candidate slice. This can lead to incorrect decisions by the target RAN node during handover when accepting / rejecting PDU sessions.

[0129] According to some examples, the 5GC (e.g., AMF or SMF) notifies the RAN node during data session establishment / modification that the data session corresponds to the original slice remapped to the alternative slice. Both the original slice and the alternative slice information (e.g., S-NSSAI) can be provided during data session establishment / modification (e.g., during PDU session establishment / modification).

[0130] For example, during an existing PDU session modification / establishment process, the SMF can directly place the alternative slice and original slice information outside the NAS message (for RAN to check), or the AMF can add such information when forwarding PDU session modifications from the SMF to the RAN node (again, outside the NAS container, for RAN to detect). As described herein, AMF can refer to the AMF currently defined by 3GPP or any appropriate network function used to manage the mobility of user equipment equipment.

[0131] In the example, an NG-RAN node can use knowledge of both the original network slice and alternative network slices to influence the selection of the target cell during handover. For instance, if the target cell is available, the target cell for restoring the original slice is selected.

[0132] According to some examples, the network's RAN nodes and / or AMF can be configured with at least one information element indicating whether the service area of ​​the original network slice should be extended to include the service area of ​​the alternative slice when the original network slice is remapped to or replaced by the alternative network slice. In examples where the AMF is configured with such information, the AMF can provide this information to the RAN node (e.g., via the NG interface, e.g., using the AMF configuration update process). Such configuration allows the operator to control the continuation of PDU sessions mapped / replaced to alternative slices, even if the original slice is not supported in the TA / cell. Even in areas where the first slice is not supported (but alternative network slices are supported), PDU sessions of the alternative network slice that were originally the first network slice are not discarded.

[0133] Based on some examples, when the RAN node does not support the original slice, the RAN node is able to decide whether to receive a PDU session for the alternative slice during the handover process.

[0134] In some examples, the UE can influence the continuity of PDU sessions remapped from a first network slice to an alternative network slice. This is useful for considering the UE's preference for continuing to remap PDU sessions to non-local network slices. The UE can include an indication of whether it wants to retain PDU sessions in the alternative slice along with the requested NSSAI during the Mobility Registration Update (MRU) process. This allows the AMF to decide whether to remove such PDU sessions while potentially retaining PDU sessions belonging to the local PDU sessions in the alternative slice for the UE.

[0135] Figure 2 An example method flow is shown between UE 202, first RAN node (gNB1) 206a, second RAN node (gNB2) 206b, network function device (AMF) 212 and SMF 214 for managing the mobility of user equipment in the network.

[0136] exist Figure 2 In the example, gNB1 206a controls cell 1 with TA1 (tracking area 1) and supports network slice 1 and network slice 2. gNB2 206b controls cell 2 with TA2 and supports network slice 2.

[0137] At position 201, UE 202 is connected to gNB1 206a. UE 202 can be in a connected RRC state (RRC_CONNECTED). UE 202 can be configured with NSSAI enabled for slices 1 and 2. The UE has registration as TA1.

[0138] The two alternatives are shown at positions 203 to 205 and 207 to 211, respectively.

[0139] At position 203, gNB1 206a is configured with the following information: When slice 1 is replaced by slice 2, the service area of ​​the network slice (slice 1 in this example) will be changed to include the service area of ​​the alternative network slice (slice 2 in this example). Slice 1 can be replaced by slice 2 by replacing the data sessions in slice 1 on slice 2. Slice 1 can be replaced by slice 2 by remapping the data sessions in slice 1 to slice 2. Thus, gNB1 206a determines that when slice 1 used for UE2 is replaced by slice 2, the service area can be changed to include the service area of ​​slice 2.

[0140] At position 205, gNB2 206b is configured with the following information: In the event that slice 1 is replaced by slice 2, the service area of ​​the network slice (in this example, slice 1) will be changed to include the service area of ​​the alternative network slice (in this example, slice 2). Thus, gNB2 206b determines that when slice 1 used for UE 202 is replaced by slice 2, the service area can be changed to include the service area of ​​slice 2.

[0141] Configurations 203 and 205 can be enforced according to operator policies. Configurations 203 and 205 can be generic, such that if any slice is replaced, the service area is changed to include the service area of ​​the replacing slice. In other examples, slice pairs where the service area is changed to include the service area of ​​the replacing slice can be defined. For example, it can be defined that if slice 1 is replaced by slice 2, the service area of ​​slice 2 should be included in the service area, but if slice 1 is replaced by slice 2, the service area of ​​slice 3 should not be included in the service area.

[0142] According to some examples, the following determination can be performed at gNB1 206a: if slice 1 is replaced by slice 2, the service area of ​​the network slice (slice 1 in this example) will be changed to include the service area of ​​the alternative network slice (slice 2 in this example).

[0143] At 207, AMF 212 is configured with the following information: If slice 1 is replaced by slice 2, the service area of ​​the network slice (slice 1 in this example) will be changed to include the service area of ​​the alternative network slice (slice 2 in this example). Similarly, this configuration can be generic for any slice, or it can be defined using slice pairs (original slice, alternative slice) that can include the service area of ​​the alternative slice.

[0144] At positions 209 and 211, AMF 212 sends the configuration of 207 to gNB1 206a and gNB2 306b, respectively. This transmission can be performed via an enhanced NG setup response or an AMF configuration update message. At positions 209 and 211, AMF 212 can send an indication that the service area can be changed to include the alternative network slice when the network slice used for the user equipment is replaced by an alternative network slice. Thus, gNB1 206a and gNB2 206b determine that when slice 1 used for UE 202 is replaced by slice 2, the service area can be changed to include slice 2.

[0145] In another option (not shown) of Alternatives 1 and 2, AMF 212 can inform OAM about the status and mapping to alternative slices. OAM can then configure RAN nodes 206a and 206b accordingly: the service area of ​​a specific slice (slice 1 in this example) will be extended to the service area of ​​an alternative slice (slice 2 in this example).

[0146] In some examples, when a service area is expanded or changed to include alternative slice 2, a timer can be used to set the period for the change to the service area before the service area is restored to the original service area.

[0147] At 213, AMF 212 determines to replace slice 1 with slice 2. This could happen, for example, when slice 1 becomes congested or undergoes maintenance in the CN. At 213, AMF 212 replaces network slice 1 with the alternative network slice 2.

[0148] At 215, AMF 212 notifies SMF 214 to replace slice 1 with alternative slice 2.

[0149] Two alternatives are shown at 217 and 219 to 221.

[0150] At 217, SMF 214 modifies the data session (e.g., PDU session) of UE 202 in slice 1 and replaces / remaps it to slice 2. SMF 214 may send an indication to gNB1 206a that at least one slice 1 data session has been mapped to an alternative slice 2. For example, SMF 214 may send a PDU session modification / establishment message (including a NAS container that will be forwarded to UE 202 and is transparent to RAN node 206a) to gNB1 206a. SMF 214 may include the original and replacement / remapped slice information outside the NAS container.

[0151] Instead of 217, at 219, SMF 214 modifies the data session (e.g., PDU session) of UE 202 in slice 1 and replaces / remaps it to slice 2. SMF 214 may send an indication to AMF 212 that the slice 1 data session has been mapped to the alternative slice 2. AMF 212 may forward this indication to gNB1 206a. For example, SMF 214 may send a PDU session modification / establishment message (including the NAS container that will be forwarded to UE 202 and is transparent to RAN node 206a) to AMF 212. AMF 212 may include the original and replacement / remapped slice information outside the NAS container and send this information to gNB1 206a.

[0152] At 223, gNB1 206a determines that at least one data session originally belonged to slice 1, but has been remapped / replaced to alternative slice 2.

[0153] At 225, gNB1 206a forwards the message received at 217 or 221 to UE 202. According to some examples, the original and replacement / remapped slice information is included outside the NAS container of the message. The message may include a PDU modifying the NAS message with remapped information outside the NAS container.

[0154] At position 227, the UE sends a measurement report to gNB1 206a. Figure 2 In the example, based on the measurement report sent at 227, gNB1 decides to hand over UE 202 to cell 2 of gNB2 206b. At 229, gNB1 206a sends a handover request to gNB2 206b, including a mapping of UE 202's data session.

[0155] At 231, when the target RAN node gNB2 206b is configured with information that the service area of ​​slice 1 will be extended to the service area of ​​alternative slice 2 (at 205 or 211), gNB2 206b accepts PDU sessions from alternative slice 2. Note that if gNB2 206b is otherwise configured, it will not accept data sessions from alternative slice 2 because the original slice 1 is not supported by gNB2 206b.

[0156] At 233, a handover (HO) request for a data session on slice 2 for UE 202 is accepted, and an acknowledgment is sent. At 235, UE 202 connects to cell 2 of gNB2 206b.

[0157] At 237, UE 202 sends an indication to AMF 212 to indicate whether UE 202 wants to maintain a data session in slice 2 that is not a local data session. A local data session can be considered to include data sessions that have not been mapped or replaced from another slice. According to some examples, this indication can be included in a Mobility Registration Update (MRU) message, which indicates that UE 202's requested NSSAI occurs when UE 202 leaves its Registration Area (RA).

[0158] At 239, AMF 212 decides to retain alternative slice 2 in the allowed NSSAI for UE 202 based on the request from UE 202 sent at 237. Therefore, AMF 212 can maintain or remove the slice 2 PDU session that was originally mapped to slice 1 based on UE 202's preferences.

[0159] At 241, AMF 212 provides alternative NSSAI to UE 202 based on 239.

[0160] Figure 3 An example message flow is shown between UE 202, first RAN node (gNB1) 206a, second RAN node (gNB2) 206b, network function apparatus (AMF) 212 for managing the mobility of user equipment in the network, and SMF 214. Figure 3 The method can be found in Figure 2 The method will be followed later.

[0161] At 343, slice 1 becomes available again (after it became unavailable, for example, due to maintenance or congestion at 213). At 343, UE 202 is served by cell 2 controlled by gNB2 206b. Consider three options for notifying gNB2 206 that slice 1 is now available again.

[0162] In Option 1, at 345, AMF 212 notifies gNB2 206 that slice 1 is now available. Although gNB2 does not support slice 2, AMF 212 is able to use information about the data session of UE 202, which is served by cell 2, having a remapped data session of slice 1, and therefore determines that it would be appropriate to send the information that cell 1 is now available to gNB2 206.

[0163] In option 2, at position 347, AMF 212 notifies gNB1 206a that slice 1 is now available again. AMF 212 is able to determine that this is appropriate because gNB1 206a supports slice 1.

[0164] In option 3, at 349, gNB1 206a infers that slice 1 is available again without being explicitly notified by AMF 212. This inference is made based on the remapping of existing data sessions of UEs served by gNB1 from slice 2 back to slice 1 (where these data sessions had previously been mapped from slice 1 to slice 2).

[0165] In options 2 and 3, at 351, an indication that slice 1 is available again can be sent from gNB1 (supporting cell 1) to gNB2 (not supporting cell 1).

[0166] At 353, gNB2 is able to use the information that slice 1 can re-available to make future switching decisions.

[0167] 355 illustrates an example decision based on information about the reavailability of slice 1. For example, if cell 1 is known to be available, a handover of UE 202 from gNB2 206b to a cell that supports cell 1 (e.g., gNB1 206a) may be preferred over a handover to a cell that does not support cell 1 (e.g., gNB3).

[0168] Figure 4 It shows the control Figure 1 An example of a control device 400 for a function of a 5GRAN or 5GC is shown. The control device may include at least one random access memory (RAM) 411a, at least one read-only memory (ROM) 411b, at least one processor 412, 413, and an input / output interface 414. At least one processor 412, 413 may be coupled to RAM 411a and ROM 411b. At least one processor 412, 413 may be configured to execute appropriate software code 415. Software code 415 may, for example, allow the execution of one or more steps to perform one or more aspects of a particular aspect. Software code 415 may be stored in ROM 411b. Control device 400 may be interconnected with another control device 400 that controls another function of the 5GRAN or 5GC. In some embodiments, each function of the 5GRAN or 5GC includes control device 400. In alternative embodiments, two or more functions of the 5GRAN or 5GC may share a control device.

[0169] Figure 5 An example of terminal 500 is shown, for example Figure 1The terminal 500 shown is a device capable of transmitting and receiving radio signals. Non-limiting examples include user equipment, mobile station (MS) or mobile device (such as a mobile phone or so-called "smartphone"), a computer equipped with a wireless interface card or other wireless interface facilities (e.g., a USB dongle), a personal data assistant (PDA) or tablet computer with wireless communication capabilities, machine-type communication (MTC) devices, Internet of Things (IoT) communication devices, or any combination of these devices. Terminal 500 can provide, for example, data communication for carrying communication. Communication can be one or more of the following: voice, email, text messages, multimedia, data, machine data, etc.

[0170] Terminal 500 can receive signals via air or radio interface 507 through appropriate means for receiving, and can transmit signals via appropriate means for transmitting radio signals. Figure 5 In this diagram, the transceiver device is schematically designated by block 506. The transceiver device 506 may be provided, for example, by means of radio components and an associated antenna arrangement. The antenna arrangement may be located inside or outside the mobile device.

[0171] Terminal 500 may be provided with at least one processor 501, at least one memory ROM 502a, at least one RAM 502b, and other possible components 503 for software and hardware-assisted execution of tasks designed to be performed, including control of access to access systems and other communication devices, and control of communication with access systems and other communication devices. At least one processor 501 is coupled to RAM 502b and ROM 502a. At least one processor 501 may be configured to execute appropriate software code 508. Software code 508 may, for example, allow execution of one or more aspects. Software code 508 may be stored in ROM 502a.

[0172] Processors, storage, and other related control devices can be provided on a suitable circuit board and / or chipset. This feature is indicated by reference numeral 504. The device may optionally have a user interface such as a keyboard 505, a touch-sensitive screen or pad, or a combination thereof. Depending on the type of device, one or more of a display, speaker, or microphone may optionally be provided.

[0173] Figure 6 Example method flow is shown. In some examples, Figure 6 The method can be performed by network function devices such as AMF 212 or SMF214.

[0174] In S6001, the method includes sending a message to a radio access network node serving a user equipment, the message including a non-access stratum container and an indication that a network slice for the user equipment, outside the non-access stratum container, has been replaced by a candidate network slice. According to some examples, the indication may include an identifier for the network slice and an identifier for the candidate network slice. The radio access node may include, for example, gNB1 206a.

[0175] Figure 7 Example method flow is shown. In some examples, Figure 7 The method can be performed by RAN node devices such as gNB2 206b.

[0176] At S7001, the method includes: determining whether the data session for the user equipment initially belonged to a network slice that has been replaced by a candidate network slice. At S7002, the method includes: based on the determination, accepting or rejecting a handover of the data session for the user equipment.

[0177] Figure 8 Example method flow is shown. In some examples, Figure 8 The method can be performed by a UE device such as UE 202.

[0178] At S8001, the method includes sending an indication to a network function for managing the mobility of a user equipment (UE) regarding whether a data session for a network slice of the UE should be removed or maintained by the network function, said network slice being replaced by an alternative network slice. The network function may include, for example, AMF 212.

[0179] Figure 9 Example method flow is shown. In some examples, Figure 9 The method can be performed, for example, by a RAN node device such as gNB1 206a.

[0180] At S9001, the method includes: receiving an indication that a network slice for a user equipment has been replaced by a candidate network slice.

[0181] At S9002, the method includes sending an indication to a target RAN node during the handover preparation process for a user equipment that the network slice for the user equipment has been replaced by a candidate network slice. The target RAN node may include, for example, gNB2 206b.

[0182] Figure 10A schematic diagram of a non-volatile storage medium 1000a (e.g., a computer disk or digital multifunction disc (DVD)) and 1000b (e.g., a Universal Serial Bus (USB) memory stick) is shown, which stores instructions and / or parameters 1002, allowing the processor to perform one or more steps of the method described above when executed by the processor.

[0183] It should be understood that the device may include or be coupled to other units or modules, such as radio components or radio heads for use in transmission and / or reception, or for transmission and / or reception. Although the device has been described as a single entity, different modules and memories may be implemented in one or more physical or logical entities.

[0184] Note that while some embodiments have been described with respect to 5G networks, similar principles can be applied to other networks and communication systems. Therefore, although some embodiments have been described above by way of example with reference to certain example architectures of wireless networks, technologies, and standards, these embodiments can be applied to any other suitable form of communication system besides those illustrated and described herein.

[0185] It should also be noted in this document that although exemplary embodiments have been described above, several changes and modifications may be made to the disclosed solutions without departing from the scope of the invention.

[0186] As used herein, “at least one of the following: ” and “at least one of ” and similar terms, where the list of two or more elements is connected by “and” or “or”, means at least any one element, or at least any two or more elements, or at least all elements.

[0187] Generally, various embodiments can be implemented in hardware or special-purpose circuit systems, software, logic, or any combination thereof. Some aspects of this disclosure can be implemented in hardware, while others can be implemented in firmware or software executed by a controller, microprocessor, or other computer device, but this disclosure is not limited thereto. Although various aspects of this disclosure may be shown or described as block diagrams, flowcharts, or other graphical representations, it is well understood that, by way of non-limiting example, these blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, special-purpose circuits or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0188] As used in this application, the term "circuit system" may refer to one or more or all of the following: (a) Hardware-only implementations (such as implementations in analog and / or digital circuit systems only), and (b) A combination of hardware circuitry and software, such as (if applicable): (i) A combination of (multiple) analog and / or digital hardware circuits and software / firmware, and (ii) Any part of the (multiple) hardware processors (including (multiple) digital signal processors), software, and (multiple) memories, which work together to enable a device (such as a mobile phone or server) to perform various functions and (c) Multiple hardware circuits and / or multiple processors (such as multiple microprocessors or portions of multiple microprocessors) that require software (e.g. firmware) to operate, but the software may not be present when operation is not required.

[0189] This definition of "circuit system" applies to all uses of the term in this application, including all uses in any of the claims. As another example, as used herein, the term "circuit system" also covers only hardware circuitry, or a processor (or multiple processors), or portions of hardware circuitry or a processor, and its (or their) accompanying software and / or firmware implementations. For example, and where applicable to specific claim elements, the term "circuit system" also covers baseband integrated circuits or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices.

[0190] Embodiments of this disclosure can be implemented via computer software executable by a data processor of a mobile device (such as in a processor entity), or via hardware, or via a combination of software and hardware. Computer software or programs, also referred to as program products, include software routines, applets, and / or macros that can be stored in any device-readable data storage medium and include program instructions for performing a specific task. A computer program product may include one or more computer-executable components that, when the program runs, are configured to perform the embodiments. The one or more computer-executable components may be at least one piece of software code or a portion thereof.

[0191] Furthermore, it should be noted in this regard that any box in the logical flow diagram can represent a program step, or an interconnected logic circuit, a combination of a box and a function, or a program step and a logic circuit, or a combination of a box and a function. Software can be stored on physical media such as memory chips or memory blocks implemented within a processor, magnetic media (such as hard disks or floppy disks), and optical media (as an example, such as DVDs and their data variants, CDs). The physical media is non-transitory.

[0192] The term “non-transient” as used in this article refers to the limitation on the medium itself (i.e., tangible, not signal), rather than the limitation on the persistence of data storage (e.g., RAM vs. ROM).

[0193] The memory can be of any type suitable for the local technical environment and can be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The data processor can be of any type suitable for the local technical environment and, by way of non-limiting example, can include one or more of the following: general-purpose computers, special-purpose computers, microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), FPGAs, gate-level circuits, and processors based on multi-core processor architectures.

[0194] The embodiments of this disclosure can be practiced in various components such as integrated circuit modules. The design of integrated circuits is largely a highly automated process. Complex and powerful software tools can be used to transform logic-level designs into semiconductor circuit designs ready for etching and formation on a semiconductor substrate.

[0195] The scope of protection sought by the various embodiments of this disclosure is defined by the independent claims. Embodiments and features (if any) described in this specification that do not fall within the scope of the independent claims are to be interpreted as examples useful for understanding the various embodiments of this disclosure. The foregoing description has provided a complete and informative description of exemplary embodiments of the present disclosure by way of non-limiting examples. However, various modifications and adaptations will be apparent to those skilled in the art when read in conjunction with the accompanying drawings and appended claims, given the foregoing description. Nevertheless, all such and similar modifications to the teachings of this disclosure will still fall within the scope of the invention as defined by the appended claims. Indeed, there are other embodiments that include combinations of one or more of the foregoing embodiments with any other of the foregoing embodiments.

Claims

1. A network function device, the device comprising: Components for sending messages to radio access network nodes serving user equipment, the messages including: a non-access stratum container, and an indication outside the non-access stratum container that the network slice of the user equipment has been replaced by a candidate network slice.

2. The apparatus according to claim 1, wherein the apparatus comprises: A component for sending to a second radio access network node an indication that the service area of ​​a network slice can be changed to include the service area of ​​the alternative network slice when the network slice used for the user equipment is replaced by the alternative network slice.

3. The apparatus according to claim 1 or 2, wherein the apparatus comprises: A component for sending to the radio access network node an indication that the service area of ​​a network slice can be changed to include the service area of ​​the alternative network slice when the network slice used for the user equipment is replaced by the alternative network slice.

4. The apparatus according to any one of the preceding claims, wherein the instruction transmitted outside the non-access stratum container comprises: The identifier of the network slice and the identifier of the alternative network slice.

5. The apparatus according to any one of the preceding claims, wherein the network function means comprises: Network functions for managing the mobility of user equipment in a network, the apparatus comprising: A component for sending a message to a session management function, the message indicating that the network slice has been replaced by the alternative network slice used for the user equipment, such that the session management function is able to perform at least one of the following: replacing at least one data session of the network slice used for the user equipment with the alternative network slice, and replacing at least one data session of the network slice used for the user equipment with at least one data session of the alternative network slice. The message that sends the indication that the network slice for the user equipment outside the non-access stratum container has been replaced by the alternative network slice includes: forwarding the indication received from the session management function that the network slice has been replaced by the alternative network slice.

6. The apparatus according to any one of the preceding claims, wherein the second radio access network supports the alternative network slice but does not support the network slice, wherein, based on an indication that the service area can be changed to include the service area of ​​the alternative network slice when the network slice for the user equipment is replaced by the alternative network slice, the second radio access network node accepts a handover of the radio access network node from the at least one data session of the alternative network slice, the alternative network slice being indicated as a replacement for the network slice.

7. The apparatus according to any one of the preceding claims, the apparatus comprising: Components for receiving mobility registration updates from the user equipment, the mobility registration updates including: an indication for the user equipment whether a data session of the network slice should be removed or maintained, the network slice being replaced by the alternative network slice; Components used to remove or maintain data sessions based on the mobility registration update.

8. The apparatus according to any one of the preceding claims, wherein the network slice becomes available after a period of unavailability, and wherein the apparatus comprises: A component for sending an indication of the availability of the network slice to at least one of the radio access network node and the second radio access network node.

9. A method performed by a network function, the method comprising: A message is sent to a radio access network node serving a user equipment, the message including: a non-access stratum container, and an indication outside the non-access stratum container that the network slice for the user equipment has been replaced by a candidate network slice.

10. A computer program comprising instructions stored thereon, the instructions being configured to perform at least the following: Sending a message to a radio access network node serving a user equipment, the message including: An indication that the non-access stratum container, and the network slice outside the non-access stratum container for the user equipment, has been replaced by an alternative network slice.

11. A radio access network node device, the device comprising: The component used to perform a data session for a user equipment that initially belonged to a network slice that has been replaced by an alternative network slice; A component for accepting or rejecting the switching of the data session for the user equipment based on the determination.

12. The apparatus of claim 11, wherein the apparatus comprises: A component for receiving from a second radio access network node an indication that the data unit session for the user equipment initially belonged to a network slice that had been replaced by a candidate network slice, wherein the determination is based on the received indication.

13. The apparatus of claim 11, wherein the apparatus does not support the network slice, and wherein the switching originates from a second radio access network node that supports the network slice and the alternative network slice, the apparatus comprising: Components used to support the alternative network slices.

14. The apparatus according to claim 11 or 12, wherein the apparatus comprises: A component for receiving from a network function an indication that the service area of ​​a network slice can be changed to include the service area of ​​the alternative network slice when the network slice for the user equipment is replaced by the alternative network slice, wherein the determination is based on the received indication.

15. The apparatus according to any one of claims 11 to 14, wherein when the user slice is congested or undergoing maintenance, the network slice for the user equipment is replaced with the alternative network slice.

16. The apparatus of any one of claims 11 to 15, wherein the network slice becomes available again after the network slice for the user equipment is replaced with the alternative network slice when the network slice is unavailable, wherein the apparatus comprises: Components for receiving an indication that a network slice has become available from network functions used to manage the mobility of user equipment devices in the network; A component for accepting or rejecting a subsequent switch based on the indication that the network slice has become available.

17. A method performed by a radio access network node, comprising: It was determined that the data session used for the user equipment originally belonged to a network slice that had been replaced by a candidate network slice. Based on the determination, the handover of the data session for the user equipment is accepted or rejected.

18. A computer program comprising instructions stored thereon, the instructions being configured to perform at least the following: It was determined that the data session used for the user equipment originally belonged to a network slice that had been replaced by a candidate network slice. Based on the determination, the radio access network node may accept or reject the handover of the data session for the user equipment.

19. A user equipment, comprising: A component for sending an instruction to a network function for managing the mobility of the user equipment, the instruction indicating whether a data session for the network slice of the user equipment, which is being replaced by the alternative network slice, should be removed or maintained by the network function.

20. The user equipment of claim 19, wherein the instruction is sent via a mobility registration update.

21. The user equipment according to claim 19 or 20, comprising: A component for receiving from a radio access network node serving the user equipment an indication that a network slice for the user equipment has been replaced by a candidate network slice.

22. A method performed by a user equipment, the method comprising: Send an instruction to a network function that manages the mobility of the user equipment, the instruction indicating whether a data session for the network slice of the user equipment that is being replaced by the alternative network slice should be removed or maintained by the network function.

23. A computer program comprising instructions stored thereon, the instructions being configured to perform at least the following: Send an instruction to a network function used to manage the mobility of a user equipment, the instruction indicating whether a data session for the network slice of the user equipment that is being replaced by the alternative network slice should be removed or maintained by the network function.

24. A radio access network node device, the device comprising: A component for receiving an indication that a network slice for a user equipment has been replaced by a candidate network slice; A component for sending an indication to a target radio access network node during the handover preparation process for the user equipment that the network slice of the user equipment has been replaced by the alternative network slice.

25. The apparatus of claim 24, wherein the instruction transmitted outside the non-access stratum container comprises: The identifier of the network slice and the identifier of the alternative network slice.

26. The apparatus according to claim 24 or 25, wherein the apparatus comprises: Components for performing the determination that, when a network slice used for a user equipment is replaced by a candidate network slice, the service area can be changed to include the service area of ​​the candidate network slice; and at least one of the following: Components for sending an indication to the target radio access network node, based on the determination, that the network slice of the user equipment has been replaced by the alternative network slice; A component used to trigger switching preparation based on the determination.

27. The apparatus of any one of claims 24 to 26, wherein the core network node receives from an NGAP (Next Generation Application Protocol) PDU session resource establishment request or PDU session resource modification request message the indication that the network slice for the user equipment has been replaced by the alternative network slice.

28. The apparatus of claim 26, wherein the determination that the service area can be changed to include the service area of ​​the alternative network slice when the network slice for the user equipment is replaced by the alternative network slice is based on an instruction received from the core network node.

29. The apparatus according to any one of claims 24 to 28, wherein the determination is based on a policy instruction or network configuration received from the 5GC.

30. A method performed by a radio access network node, the method comprising: Receive an indication that the network slice used for the user equipment has been replaced by a candidate network slice; Send an indication to the target radio access network node during the handover preparation process for the user equipment that the network slice for the user equipment has been replaced by the alternative network slice.

31. A computer program comprising instructions stored thereon, the instructions being configured to perform at least the following: Receive an indication that the network slice used for the user equipment has been replaced by a candidate network slice; Send an indication to the target radio access network node during the handover preparation process for the user equipment that the network slice for the user equipment has been replaced by the alternative network slice.

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