Managing multiple simultaneous registrations to a single network or multiple networks using a same access type

Abstract

The disclosure relates to an apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus at least to perform: sending (500), to a core network function via a base station, a registration request message indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using a same access type; and negotiating (502), with the core network function via the base station, a reduced apparatus capability to be used by the base station to configure the apparatus to communicate with the base station when the apparatus has multiple simultaneous registrations to a single network or to multiple networks using the same access type.

Description

[0001] MANAGING MULTIPLE SIMULTANEOUS REGISTRATIONS TO A SINGLE NETWORK OR MULTIPLE NETWORKS USING A SAME ACCESS TYPE

[0002] Field of the disclosure

[0003] The present disclosure relates to an apparatus, a method, and a computer program for managing multiple simultaneous registrations to a single network or multiple networks using a same access type in a communication system.

[0004] Background

[0005] A communication system can be seen as a facility that enables communication sessions between two or more entities such as communication devices, base stations and / or other nodes by providing carriers between the various entities involved in the communications path.

[0006] The communication system may be a wireless communication system. Examples of wireless systems comprise public land mobile networks (PLMN) operating based on radio standards such as those provided by 3GPP, satellite-based communication systems and different wireless local networks, for example wireless local area networks (WLAN). The wireless systems can typically be divided into cells, and are therefore often referred to as cellular systems.

[0007] 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 achieved. Communication protocols and / or parameters which shall be used for the connection are also typically defined. Examples of standard are the so-called 5G standards.

[0008] Summary

[0009] According to an aspect there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: sending, to a core network function via a base station, a registration request message indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using a same access type; and negotiating, with the core network function via the base station, a reduced apparatus capability to be used by the base station to configure the apparatus to communicate with the base station when the apparatus has multiple simultaneous registrations to a single network or to multiple networks using the same access type.

[0010] The multiple simultaneous registrations to the single network or multiple networks may use a 3GPP access (i.e. , cellular access).

[0011] The registration request message explicitly or implicitly may indicate that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using the same access type.

[0012] The registration request message may comprise a multiple simultaneous registrations to a single network or multiple networks using the same access type field that explicitly indicates that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using the same access type; or the registration request message may comprise a registration identifier field implicitly indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using the same access type.

[0013] The negotiating, with the core network function via the base station, the reduced apparatus capability may comprise: receiving, from the core network function via the base station, a registration accept message indicating the reduced apparatus capability, wherein the reduced apparatus capability is determined by the core network function; and sending, to the core network function via the base station, a registration complete message indicating confirmation of the reduced apparatus capability determined by the core network function. The negotiating, with the core network function via the base station, the reduced apparatus capability may comprise: sending, to the core network function via the base station, the registration request message indicating the reduced apparatus capability, wherein the reduced apparatus capability is determined by the apparatus; and receiving, from the core network function via the base station, a registration accept message indicating confirmation of the reduced apparatus capability determined by the apparatus or an alternative reduced apparatus capability, wherein the alternative reduced apparatus capability is determined by the core network function.

[0014] The at least one memory may store instructions that, when executed by the at least one processor, further cause the apparatus at least to perform: receiving, from the core network function via the base station, a registration accept message indicating a first identifier identifying a full apparatus capability and at least one second identifier identifying at least one reduced apparatus capability.

[0015] The at least one memory may store instructions that, when executed by the at least one processor, further cause the apparatus at least to perform: based on performing a registration to a single network, sending, to the base station, a message comprising the first identifier, the first identifier identifying the full apparatus capability, the message comprising the first identifier configured to cause the base station to configure the apparatus to communicate with the base station based on the full apparatus capability.

[0016] The at least one memory may store instructions that, when executed by the at least one processor, further cause the apparatus at least to perform: based on performing multiple simultaneous registrations to a single network or multiple networks using the same access type, sending, to the base station, a message comprising the at least one second identifier identifying the at least one reduced apparatus capability, the message comprising the at least one second identifier configured to cause the base station to configure the apparatus to communicate with the base station based on the reduced apparatus capability. The at least one memory may store instructions that, when executed by the at least one processor, further cause the apparatus at least to perform: based on performing multiple simultaneous registrations to a single network or multiple networks using the same access type, sending, to the base station, a message comprising information indicating a reduced apparatus capability due to multiple registrations to a single network or multiple networks using the same access type, the message comprising the information configured to cause the base station to obtain the reduced apparatus capability from the core network function and to configure the apparatus to communicate with the base station based on the reduced apparatus capability.

[0017] The first identifier identifying the full apparatus capability, the at least one second identifier identifying the at least one reduced apparatus capability or the information indicating a reduced apparatus capability due to multiple registrations to a single network or multiple networks using the same access type may be sent in a radio resource control message.

[0018] The reduced apparatus capability may comprise a percentage of the full apparatus capability.

[0019] A full apparatus capability may comprise at least one of: a number of component carriers; or a number of cell groups.

[0020] Simultaneously registering with a single network or multiple networks using the same access type may comprise simultaneously establishing radio connections with a single cellular or multiple networks of the same access type.

[0021] According to an aspect there is provided an apparatus comprising means for: sending, to a core network function via a base station, a registration request message indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using a same access type; and negotiating, with the core network function via the base station, a reduced apparatus capability to be used by the base station to configure the apparatus to communicate with the base station when the apparatus has multiple simultaneous registrations to a single network or to multiple networks using the same access type.

[0022] According to an aspect there is provided an apparatus comprising circuitry configured to perform sending, to a core network function via a base station, a registration request message indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using a same access type; and negotiating, with the core network function via the base station, a reduced apparatus capability to be used by the base station to configure the apparatus to communicate with the base station when the apparatus has multiple simultaneous registrations to a single network or to multiple networks using the same access type.

[0023] According to an aspect there is provided a method comprising: sending, to a core network function via a base station, a registration request message indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using a same access type; and negotiating, with the core network function via the base station, a reduced apparatus capability to be used by the base station to configure the apparatus to communicate with the base station when the apparatus has multiple simultaneous registrations to a single network or to multiple networks using the same access type.

[0024] The multiple simultaneous registrations to the single network or multiple networks may use a 3GPP access (i.e. , cellular access).

[0025] The registration request message explicitly or implicitly may indicate that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using the same access type.

[0026] The registration request message may comprise a multiple simultaneous registrations to a single network or multiple networks using the same access type field that explicitly indicates that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using the same access type; or the registration request message may comprise a registration identifier field implicitly indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using the same access type.

[0027] The negotiating, with the core network function via the base station, the reduced apparatus capability may comprise: receiving, from the core network function via the base station, a registration accept message indicating the reduced apparatus capability, wherein the reduced apparatus capability is determined by the core network function; and sending, to the core network function via the base station, a registration complete message indicating confirmation of the reduced apparatus capability determined by the core network function.

[0028] The negotiating, with the core network function via the base station, the reduced apparatus capability may comprise: sending, to the core network function via the base station, the registration request message indicating the reduced apparatus capability, wherein the reduced apparatus capability is determined by the apparatus; and receiving, from the core network function via the base station, a registration accept message indicating confirmation of the reduced apparatus capability determined by the apparatus or an alternative reduced apparatus capability, wherein the alternative reduced apparatus capability is determined by the core network function.

[0029] The method may comprise: receiving, from the core network function via the base station, a registration accept message indicating a first identifier identifying a full apparatus capability and at least one second identifier identifying at least one reduced apparatus capability.

[0030] The method may comprise: based on performing a registration to a single network, sending, to the base station, a message comprising the first identifier, the first identifier identifying the full apparatus capability, the message comprising the first identifier configured to cause the base station to configure the apparatus to communicate with the base station based on the full apparatus capability. The method may comprise: based on performing multiple simultaneous registrations to a single network or multiple networks using the same access type, sending, to the base station, a message comprising the at least one second identifier identifying the at least one reduced apparatus capability, the message comprising the at least one second identifier configured to cause the base station to configure the apparatus to communicate with the base station based on the reduced apparatus capability.

[0031] The method may comprise: based on performing multiple simultaneous registrations to a single network or multiple networks using the same access type, sending, to the base station, a message comprising information indicating a reduced apparatus capability due to multiple registrations to a single network or multiple networks using the same access type, the message comprising the information configured to cause the base station to obtain the reduced apparatus capability from the core network function and to configure the apparatus to communicate with the base station based on the reduced apparatus capability.

[0032] The first identifier identifying the full apparatus capability, the at least one second identifier identifying the at least one reduced apparatus capability or the information indicating a reduced apparatus capability due to multiple registrations to a single network or multiple networks using the same access type may be sent in a radio resource control message.

[0033] The reduced apparatus capability may comprise a percentage of the full apparatus capability.

[0034] A full apparatus capability may comprise at least one of: a number of component carriers; or a number of cell groups. Simultaneously registering with a single network or multiple networks using the same access type may comprise simultaneously establishing radio connections with a single cellular or multiple networks of the same access type.

[0035] According to an aspect there is provided a computer program comprising computer executable code which when run on at least one processor is configured to perform: sending, to a core network function via a base station, a registration request message indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using a same access type; and negotiating, with the core network function via the base station, a reduced apparatus capability to be used by the base station to configure the apparatus to communicate with the base station when the apparatus has multiple simultaneous registrations to a single network or to multiple networks using the same access type.

[0036] According to an aspect there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a user equipment via a base station, a registration request message indicating that the user equipment supports multiple simultaneous registrations to a single network or multiple networks using the same access type; and negotiating, with the user equipment, a reduced user equipment capability to be used by the base station to configure the user equipment to communicate with the base station when the user equipment has multiple simultaneous registrations to a single or to multiple networks using the same access type.

[0037] The negotiating, with the user equipment, a reduced user equipment capability may comprise: sending, to the user equipment via the base station, a registration accept message comprising information indicating the reduced user equipment capability, wherein the reduced apparatus capability is determined by the apparatus; and receiving, from the user equipment, a registration complete indicating confirmation of the reduced user equipment capability determined by the apparatus. The negotiating, with the user equipment, the reduced user equipment capability may comprise: receiving, from the user equipment via the base station, the registration request message indicating the reduced user equipment capability, wherein the reduced apparatus capability is determined by the user equipment; and sending, to the user equipment via the base station, a registration accept message indicating confirmation of the reduced user equipment capability determined by the user equipment or an alternative reduced user equipment capability, wherein the alternative reduced user equipment capability is determined by the apparatus.

[0038] The at least one memory may store instructions that, when executed by the at least one processor, cause the apparatus at least to perform: sending, to another core network function, a request to determine a full user equipment capability and at least one reduced user equipment capability; and receiving, from the other core network function, a first identifier identifying a full user equipment capability determined by the other core network function, a full user equipment capability determined by the other core network function, at least one second identifier identifying at least one reduced user equipment capability determined by the other core network function and at least one reduced user equipment capability determined by the other core network function.

[0039] The other core network function may store the first identifier identifying the full user equipment capability determined by the other core network function, the full user equipment capability determined by the other core network function, the at least one second identifier identifying the at least one reduced user equipment capability determined by the other core network function and the at least one reduced user equipment capability determined by the other core network function.

[0040] The at least one memory may store instructions that, when executed by the at least one processor, cause the apparatus at least to perform: sending, to the user equipment via the base station and to the base station, the first identifier identifying the full user equipment capability determined by the other core network function and the at least one second identifier identifying the at least one reduced user equipment capability determined by the other core network function. According to an aspect there is provided an apparatus comprising means for: receiving, from a user equipment via a base station, a registration request message indicating that the user equipment supports multiple simultaneous registrations to a single network or multiple networks using the same access type; and negotiating, with the user equipment, a reduced user equipment capability to be used by the base station to configure the user equipment to communicate with the base station when the user equipment has multiple simultaneous registrations to a single or to multiple networks using the same access type.

[0041] According to an aspect there is provided an apparatus comprising circuitry configured to perform: receiving, from a user equipment via a base station, a registration request message indicating that the user equipment supports multiple simultaneous registrations to a single network or multiple networks using the same access type; and negotiating, with the user equipment, a reduced user equipment capability to be used by the base station to configure the user equipment to communicate with the base station when the user equipment has multiple simultaneous registrations to a single or to multiple networks using the same access type.

[0042] According to an aspect there is provided a method comprising: receiving, from a user equipment via a base station, a registration request message indicating that the user equipment supports multiple simultaneous registrations to a single network or multiple networks using the same access type; and negotiating, with the user equipment, a reduced user equipment capability to be used by the base station to configure the user equipment to communicate with the base station when the user equipment has multiple simultaneous registrations to a single or to multiple networks using the same access type.

[0043] The negotiating, with the user equipment, a reduced user equipment capability may comprise: sending, to the user equipment via the base station, a registration accept message comprising information indicating the reduced user equipment capability, wherein the reduced apparatus capability is determined by the apparatus; and receiving, from the user equipment, a registration complete indicating confirmation of the reduced user equipment capability determined by the apparatus.

[0044] The negotiating, with the user equipment, the reduced user equipment capability may comprise: receiving, from the user equipment via the base station, the registration request message indicating the reduced user equipment capability, wherein the reduced apparatus capability is determined by the user equipment; and sending, to the user equipment via the base station, a registration accept message indicating confirmation of the reduced user equipment capability determined by the user equipment or an alternative reduced user equipment capability, wherein the alternative reduced user equipment capability is determined by the apparatus.

[0045] The method may comprise: sending, to another core network function, a request to determine a full user equipment capability and at least one reduced user equipment capability; and receiving, from the other core network function, a first identifier identifying a full user equipment capability determined by the other core network function, a full user equipment capability determined by the other core network function, at least one second identifier identifying at least one reduced user equipment capability determined by the other core network function and at least one reduced user equipment capability determined by the other core network function.

[0046] The other core network function, may store the first identifier identifying the full user equipment capability determined by the other core network function, the full user equipment capability determined by the other core network function, the at least one second identifier identifying the at least one reduced user equipment capability determined by the other core network function and the at least one reduced user equipment capability determined by the other core network function.

[0047] The method may comprise: sending, to the user equipment via the base station and to the base station, the first identifier identifying the full user equipment capability determined by the other core network function and the at least one second identifier identifying the at least one reduced user equipment capability determined by the other core network function.

[0048] According to an aspect there is provided a computer program comprising computer executable code which when run on at least one processor is configured to perform: receiving, from a user equipment via a base station, a registration request message indicating that the user equipment supports multiple simultaneous registrations to a single network or multiple networks using the same access type; and negotiating, with the user equipment, a reduced user equipment capability to be used by the base station to configure the user equipment to communicate with the base station when the user equipment has multiple simultaneous registrations to a single or to multiple networks using the same access type.

[0049] According to an aspect, there is provided a computer readable medium comprising program instructions stored thereon for performing at least one of the above methods.

[0050] According to an aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least one of the above methods.

[0051] According to an aspect, there is provided a non-volatile tangible memory medium comprising program instructions stored thereon for performing at least one of the above methods.

[0052] In the above, many different aspects have been described. It should be appreciated that further aspects may be provided by the combination of any two or more of the aspects described above.

[0053] Various other aspects are also described in the following detailed description and in the attached claims. List of abbreviations

[0054] AF: Application Function

[0055] Al: Artificial Intelligence

[0056] AMF: Access and Mobility Management Function

[0057] API: Application Programming Interface

[0058] BS: Base Station

[0059] CM: Connection Management

[0060] CU: Centralized Unit

[0061] DL: Downlink

[0062] DU: Distributed Unit gNB: gNodeB

[0063] GSM: Global System for Mobile communication

[0064] HSS: Home Subscriber Server

[0065] IE: Information Element loT : Internet of Things

[0066] LMF: Location Management Function

[0067] LPP: Location Positioning Protocol

[0068] LTE: Long Term Evolution

[0069] MAC: Medium Access Control

[0070] ML: Machine Learning

[0071] MS: Mobile Station

[0072] MTC: Machine Type Communication

[0073] NEF: Network Exposure Function

[0074] NF: Network Function

[0075] NR: New radio

[0076] NRF: Network Repository Function

[0077] PDU: Packet Data Unit

[0078] PLMN: Public Land Mobile Network

[0079] RAM: Random Access Memory

[0080] (R)AN: (Radio) Access Network

[0081] RM: Registration Management ROM: Read Only Memory

[0082] SINR: Signal to Interference plus Noise Ratio

[0083] SMF: Session Management Function

[0084] SNPN: Standalone Non-Public Network

[0085] TR: Technical Report

[0086] TS: Technical Specification

[0087] LICMF: UE capability Management Function

[0088] UE: User Equipment

[0089] UMTS: Universal Mobile Telecommunication System

[0090] 3GPP: 3rdGeneration Partnership Project

[0091] 5G: 5thGeneration

[0092] 5GC: 5G Core network

[0093] 5GS: 5G System

[0094] Brief Description of the Figures

[0095] Embodiments will now be described, by way of example only, with reference to the accompanying Figures in which:

[0096] Fig. 1 shows a schematic representation of a 5G system;

[0097] Fig. 2 shows a schematic representation of a control apparatus;

[0098] Fig. 3 shows a schematic representation of a user equipment;

[0099] Fig. 4 shows a signaling diagram of two implementations for managing multiple simultaneous registrations to a single network or multiple networks using a same access type;

[0100] Fig. 5 shows a block diagram of a method for managing multiple simultaneous registrations to a single network or multiple networks using a same access type performed by an access and mobility management function; Fig. 6 shows a block diagram of a method for managing simultaneous multiple registrations to a single network or multiple cellular networks using a same access type performed by a user equipment; and

[0101] Fig. 7 shows a schematic representation of a non-volatile memory medium storing instructions which when executed by a processor allow a processor to perform one or more of the steps of the methods of Fig. 5 and Fig. 6.

[0102] Detailed Description of the Figures

[0103] In the following certain embodiments are explained with reference to mobile communication devices capable of communication via a wireless cellular system and mobile communication systems serving such mobile communication devices. Before explaining in detail the exemplifying embodiments, certain general principles of a wireless communication system, access systems thereof, and mobile communication devices are briefly explained with reference to Fig. 1 , Fig.2 and Fig.3 to assist in understanding the technology underlying the described examples.

[0104] FIG. 1 shows a schematic representation of a 5G system (5GS). The 5GS may comprises user equipments (UEs) and public land mobile networks (PLMNs). A PLMN may comprise an LTE PLMN, a 5G PLMN or a subsequent generation PLMN.

[0105] A 5G PLMN may comprise a 5G (radio) access network (5G (R)AN), a 5G core network (5GC), one or more application functions (AF) and one or more data networks (DN). A UE may be registered to a single PLMN or to multiple PLMNs. As used herein, the term “multiple” refers to two or more or a plural amount.

[0106] The 5G (R)AN may comprise one or more gNodeB (gNB) distributed unit functions connected to one or more gNodeB (gNB) centralized unit functions.

[0107] The 5GC may comprise an access and mobility management function (AMF), a session management function (SMF), an authentication server function (AUSF), a user data management (UDM), a user plane function (UPF), a network exposure function (NEF), a unified data repository (UDR), an application function (AF), a location management function (LMF) and / or a UE capability management function.

[0108] Fig. 2 illustrates an example of a control apparatus 200 for controlling a function of the (R)AN or the 5GC as illustrated on Fig. 1 . The control apparatus may comprise at least one random access memory (RAM) 211 a, at least on read only memory (ROM) 211 b, at least one processor 212, 213 and an input / output interface 214. The at least one processor 212, 213 may be coupled to the RAM 211a and the ROM 211 b. The at least one processor 212, 213 may be configured to execute an appropriate software code 215. The software code 215 may for example allow to perform one or more steps operations to perform one or more of the present aspects. The software code 215 may be stored in the ROM 211 b. The control apparatus 200 may be interconnected with another control apparatus 200 controlling another function of the 5G (R)AN or the 5GC. In some embodiments, each function of the (R)AN or the 5GC comprises a control apparatus 200. In alternative embodiments, two or more functions of the (R)AN or the 5GC may share a control apparatus.

[0109] Fig. 3 illustrates an example of a UE 300, such as the UE illustrated on Fig. 1 . The UE 300 may be provided by any device capable of sending and receiving radio signals. Non-limiting examples comprise a user equipment, a mobile station (MS) or mobile device such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), a personal data assistant (PDA) or a tablet provided with wireless communication capabilities, a machine-type communications (MTC) device, a Cellular Internet of things (CloT) device or any combinations of these or the like. The UE 300 may provide, for example, communication of data for carrying communications. The communications may be one or more of voice, electronic mail (email), text message, multimedia, data, machine data and so on.

[0110] The UE 300 may receive signals over an air or radio interface 307 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Fig. 3 transceiver apparatus is designated schematically by block 306. The transceiver apparatus 306 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

[0111] The UE 300 may be provided with at least one processor 301 , at least one memory ROM 302a, at least one RAM 302b and other possible components 303 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The at least one processor 301 is coupled to the RAM 302b and the ROM 302a. The at least one processor 301 may be configured to execute an appropriate software code 308. The software code 308 may for example allow to perform one or more of the present aspects. The software code 308 may be stored in the ROM 302a.

[0112] The processor, storage and other relevant control apparatus can be provided on an appropriate circuit board and / or in chipsets. This feature is denoted by reference 304. The device may optionally have a user interface such as keypad 305, touch sensitive screen or pad, combinations thereof or the like. Optionally one or more of a display, a speaker and a microphone may be provided depending on the type of the device.

[0113] One or more aspect of this disclosure relates to managing simultaneous registrations to a single network or to multiple networks (e.g., one or more networks or plural networks).

[0114] A UE may have multiple simultaneous registrations to a single network or multiple networks using a same access type. The UE may simultaneously establish radio resource control (RRC) connections with the single network or the multiple networks. The RRC connections may serve a same packet data unit (PDU) session. For example, the RRC connections may serve different parts of a same multi-access (MA) PDU. Alternatively, each RRC connection may serve different PDU sessions. In this disclosure a network may refer to a public land mobile network (PLMN), for example a LTE PLMN, a 5G PLMN or a 6G PLMN or a standalone non- public network (SNPN), for example a LTE SNPN, a 5G SNPN or a 6G SNPN.

[0115] In this disclosure an access type may refer to 3GPP access or a non-3GPP access. A 3GPP access may refer to a cellular access, such as an LTE access, a 5G access or a 6G access. A non-3GPP access may refer to a non-cellular access, such as a Wi-Fi access.

[0116] For example, a UE may have multiple simultaneously registrations to a single PLMN or to multiple PLMNs. The multiple simultaneously registrations may use a same access type (e.g., 3GPP access). The UE may establish multiple RRC connections with a single PLMN (e.g., a first RRC connection with gNB1 of PLMN and a second RRC connection with gNB2 of PLMN) or with multiple PLMNs (e.g., a first RRC connection with gNB1 of PLMN1 and second RRC connection with gNB2 of PLMN2).

[0117] In this disclosure a UE capability may refer to a UE radio capability, a UE radio access capability, UE radio capability information or UE radio access capability information. The UE capability may comprise a full UE capability or a reduced UE capability.

[0118] The full UE capability may comprise at least one of a number of component carriers supported by the UE, a preference for cell groups on a maximum number of component carriers supported by the UE or other UE capability information. The full UE capability may comprise the UE radio capability information defined in 3GPP TS 38.300. The full UE capability may comprise information on or concerning radio access technologies that the UE supports (e.g., power class, frequency bands, etc.). A detailed list of UE capability information may be found in 3GPP TS 38.306 and 3GPP TS 36.306.

[0119] The UE may report the full UE capability when or based on a request by the network (e.g., the network requests the UE capability). The network may request what UE capability the UE has to report based on band information. The full UE capability may be represented by a full UE capability ID. The full UE capability ID may be exchanged in non-access stratum signalling over the air and in network signalling instead of the UE capability.

[0120] The full UE capability may be sufficiently large that it may be undesirable to send the full UE capability across the radio interface at every transition of UE connection management (CM) state in the AMF from CM-IDLE to CM-CONNECTED. To avoid this radio overhead, the AMF may store the full UE capability during CM-IDLE state for the UE and RM-REGISTERED state for the UE. The AMF may send a most up to date full UE capability to the RAN in a N2 REQUEST message.

[0121] The RAN may store the full UE capability, received in the N2 message or obtained from the UE, for the duration of the UE staying in RRC_CONNECTED or RRCJNACTIVE state.

[0122] It will be understood that although in the following one or more aspect will be discussed in the context of a 5G system to increase the intelligibility, these aspects may be applied to other cellular systems, such as previous generation systems (e.g., LTE systems) or subsequent generation systems (e.g., 6G systems).

[0123] In a 5G system, a UE may simultaneously register to a first 5G PLMN with a first (R)AN comprising a first gNB and to a second 5G PLMN with a second (R)AN comprising a second gNB. The UE may simultaneously establish a first RRC connection to the first 5G PLMN via the first gNB and a second RRC connection to the second 5G PLMN via the second gNB. In other words, the UE may have a first RRC connection to the first 5G PLMN via the first gNB and at the same time the UE has a second RRC connection to the second 5G PLMN via the second gNB.

[0124] In such scenario the first gNB may not be aware of the existence of the second RRC connection. The first gNB may therefore assume that a full UE capability may be used to configure the UE to communicate with the first gNB to serve the first RRC connection. This may however lead to RRC reconfiguration failures as explained below.

[0125] For example, let’s assume that a full UE capability may comprise four component carriers in a frequency band. Initially, the UE may register to the first 5G PLMN. The UE may establish the first RRC connection with the first 5G PLMN via the first gNB. The first gNB may configure the UE to communicate with the first gNB based on the full UE capability. The first gNB may configure the UE to communicate with the first gNB using two component carriers in the frequency band.

[0126] In this disclosure the term dual steering may refer to the ability to perform steering, switching and splitting of traffic using a multi-access PDU session (MA PDU Session) over two 3GPP access. Note that the access traffic steering, switching and splitting (ATSSS) feature available up to 3GPP Rel-18 allows to steer, switch, split traffic using MA PDU Session over a 3GPP access and a Non-3GPP access.

[0127] Subsequently, the UE may register to the second 5G PLMN. The UE may establish the second RRC connection with the second 5G PLMN via the second gNB. The registering to the second 5G PLMN may be triggered when the UE wants to steer, split or switch traffic between two or more 3GPP access. The registering to the second 5G PLMN may be triggered by an application layer of the UE. The second gNB may configure the UE to communicate with the second gNB based on the full UE capability. The second gNB may configure the UE to communicate with the second gNB using three component carriers in the frequency band. This would lead to a RRC reconfiguration failure as the first gNB has already configured the UE to communicate with the first gNB using two component carriers in the frequency band.

[0128] One or more aspect of this disclosure provides a solution to avoid RRC reconfiguration failures when a UE has simultaneous registrations to a single 5G PLMN or multiple 5G PLMNs (e.g., one or more 5G PLMNs or plural 5G PLMNs) using a same access type (e.g., 3GPP access). More generally, one or more aspect of this disclosure provides a solution to avoid reconfiguration failures when a UE has simultaneous registrations to a single network or multiple networks (e.g., one or more networks or plural networks) using a same access type (e.g., 3GPP access).

[0129] During registration

[0130] A UE may send, to an AMF via a gNB, a registration reguest message indicating that the UE supports simultaneous registrations to a single 5G PLMN or multiple 5G PLMNs using the same access type (e.g., 3GPP access).

[0131] The registration reguest message may indicate that the UE supports simultaneous registrations to a single 5G PLMN or multiple 5G PLMNs for access traffic steering, switching and splitting with statically reduced UE capability. Here, the expression “statically reduced UE capability” may refer to the fact that the reduced UE capability may be fixed for a whole registration period (e.g., the entirety of a registration period). Here the expression ‘reduced UE capability’ may refer to less than the full UE capability.

[0132] The registration reguest message may explicitly or implicitly indicate that the UE supports simultaneous registrations to multiple 5G PLMNs.

[0133] The registration reguest message may comprise a registration identifier implicitly indicating that the UE supports simultaneous registrations to a single 5G PLMN or multiple 5G PLMNs. That is; the existence of the registration identifier in the registration reguest message indicates that the UE supports simultaneous registrations to a single 5G PLMN or multiple 5G PLMNs. Alternatively, an additional indicator or the presence of new information (e.g., registration ID) may explicitly indicate that the UE supports simultaneous registrations to multiple 5G PLMNs.

[0134] The AMF may determine that the UE supports simultaneous registrations using the same access network type to a single 5G PLMN or multiple 5G PLMNs based on the registration reguest message. The AMF may determine that the gNB should not configure the UE to communicate with the gNB based on a full UE capability when the UE does not support simultaneous registrations using the same access network type to a single 5G PLMN or multiple 5G PLMNs, or when the UE support simultaneous registrations using the same access network type to a single 5G PLMN or multiple 5G PLMNs and is not simultaneously registered using the same access network type to a single 5G PLMN or multiple 5G PLMNs.

[0135] The AMF may determine that the gNB should configure the UE to communicate with the BS based on a reduced UE capability when the UE supports simultaneous registrations and is simultaneously registered using the same access network type to a single 5G PLMN or multiple 5G PLMNs.

[0136] More specifically, the AMF may determine that the gNB should configure the UE to communicate with the BS based on a reduced UE capability when the UE supports simultaneous registrations using the same access network type to a single 5G PLMN or multiple 5G PLMNs and is simultaneously registered using the same access network type to a single 5G PLMN or multiple 5G PLMNs based on local configuration or operator policy.

[0137] In this disclosure, the term UE radio capability signalling optimisation (RACS) may refer to the following features.

[0138] With the increase of the size of UE capability driven for example by additional frequency bands and combinations thereof for E-UTRA and NR) an efficient approach to signal UE capability over the radio interface and other network interfaces may be defined with RACS. RACS may work by assigning an identifier to represent UE capability. This identifier may be called UE capability ID. The capability ID may be an alternative to the signalling of the UE capability over the radio interface, within NG- RAN, from NG-RAN to E-UTRAN, from AMF to NG-RAN and between CN nodes supporting RACS. The UE capability ID may be a short pointer with format defined in 3GPP TS 23.003 that may be used to uniquely identify UE capability. The UE capability ID may be assigned either by a serving PLMN or by a UE manufacturer. The type of UE capability ID (UE manufacturer-assigned or PLMN-assigned) may be distinguished when a UE capability ID is signalled.

[0139] The UCMF may store dictionary entries (e.g., a map) related to PLMN-assigned or manufacturer-assigned UE capability IDs. The UCMF may store all UE capability ID in a PLMN and may be responsible for assigning every PLMN-assigned UE capability ID in this PLMN. The UCMF may store the UE capability IDs alongside (e.g., in association with) the UE capability.

[0140] In a first implementation wherein a UE does not support radio capabilities signalling optimization, the UE may negotiate, with the AMF via the gNB, a reduced UE capability to be used by the gNB to configure the UE to communicate with the gNB when the UE is simultaneously registered using the same access network type to a single PLMN or multiple 5G PLMNs. In this way, the risk of RRC reconfiguration failures (explained above) may be reduced.

[0141] The UE may receive, from the AMF via the gNb, a registration accept message indicating a reduced UE capability determined by the AMF. The registration accept message may comprise the reduced UE capability or control information to derive the reduced UE capability (e.g., a percentage relative to a full UE capability). The reduced UE capability may be limited to simultaneous registrations to two 5G PLMNs (e.g., dual registrations). The UE may send, to the AMF via the gNB, a registration complete message indicating confirmation (e.g., agreement) of the reduced apparatus capability determined by the AMF.

[0142] The AMF may send, to the gNB, a message indicating the reduced UE capability determined by the AMF. The message may comprise the reduced UE capability or control information to derive the reduced UE capability (e.g., a percentage relative to a full UE capability). The message may be sent over a NGAP interface.

[0143] Alternatively, the AMF may not send, to the gNB, a message indicating the reduced UE capability determined by the AMF.

[0144] In a second implementation wherein UE does not support radio capabilities signalling optimization, the UE may negotiate, with the AMF via the gNB, a reduced UE capability to be used by the gNB to configure the UE to communicate with the gNB when the UE is simultaneously registered using the same access network type to a single 5G PLMN or multiple 5G PLMNs. In this way, the risk of RRC reconfiguration failures (explained above) may be reduced.

[0145] The UE may send, to the AMF via the gNB, the registration request message indicating a reduced UE capability determined by the UE. The reduced UE capability may be determined based on the UE being simultaneously registered using the same access network type to a single 5G PLMN or multiple 5G PLMNs. The registration request message may comprise the reduced UE capability or control information to derive the reduced UE capability (e.g., a percentage relative to a full UE capability). The reduced UE capability may be limited to simultaneous registrations to two 5G PLMNs (e.g., dual registrations). The UE may receive, from the AMF via the gNB, a registration accept message indicating confirmation (e.g., agreement) of the reduced UE capability determined by the UE or a reduced UE capability determined by the AMF.

[0146] The AMF may send, to the gNB, a message indicating the reduced UE capability determined by the UE or the reduced UE capability determined by the AMF. The message may comprise the reduced UE capability determined by the UE or the reduced UE capability determined by the AMF or control information to derive the reduced UE capability determined by the UE or the reduced UE capability determined by the AMF (e.g., a percentage relative to a full UE capability). The message may be sent over a NGAP interface. Alternatively, the AMF may not send, to the gNB, a message indicating the reduced UE capability determined by the AMF.

[0147] Fig. 4 shows a signaling diagram of the first implementation and the second in relation to Fig. 4.2.2.2.2-1 of 3GPP TS 23.502 (v18.2.0).

[0148] In a third implementation wherein UE supports radio capabilities signalling optimization, the AMF may send to a UCMF, a request to determine a full user equipment capability and a reduced user equipment capability. The UCMF may determine a full UE capability and a reduced UE capability.

[0149] The full UE capability may be used by the gNB to configure the UE to communicate with the gNB when the UE is registered to a single 5G PLMN and when the UE has established a single RRC connection).

[0150] The reduced UE capability may be used by the gNB to configure the UE to communicate with the gNB when the UE is simultaneously registered using the same access type to a single 5G PLMN or multiple 5G PLMNs and when the UE has simultaneously established multiple RRC connections.

[0151] The UCMF may determine the full UE capability and at least one reduced UE capability. The UCMF may determine a first identifier (i.e., first UE capability ID) identifying the full UE capability and at least one second identifier (i.e., at least one second UE capability ID) identifying the at least one reduced UE capability. The UCMF may store the full UE capability, the at least one reduced UE capability, the first identifier identifying the full UE capability and the at least one second identifier identifying the at least one reduced UE capability.

[0152] The UCMF may determine the full UE capability and the at least one reduced UE capability based on information provided by a manufacturer or vendor of the UE or by an operator of a PLMN of the UCMF. The AMF may receive from the LICMF a first identifier identifying the full UE capability determined by the LICMF, the full UE capability determined by the UCMF, the at least one second identifier identifying the at least one reduced UE capability determined by the UCMF and the at least one reduced UE capability determined by the UCMF.

[0153] The AMF may send, to the UE via the gNB, a registration accept message indicating the first identifier identifying the full UE capability determined by the UCMF and the at least one second identifier identifying the at least one reduced UE capability determined by the UCMF and the at least one reduced UE capability determined by the UCMF.

[0154] The AMF may send, to the gNB (e.g., via NGAP), a message indicating the first identifier identifying the full UE capability determined by the UCMF and the at least one second identifier identifying the at least one reduced UE capability determined by the UCMF and the at least one reduced UE capability determined by the UCMF.

[0155] A reduced UE capability may comprise a percentage of a full UE capability. For example, a reduced UE capability may comprise 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90% of a full UE capability. In other words, a full UE capability is a greater capability than a reduced UE capacity. A full apparatus capability refers to a non-reduced UE capability. For example, if a full UE capability permits use of a number of component carriers in a frequency band, a reduced UE capability permits use of a lesser number of component carriers in a frequency band.

[0156] After registration

[0157] The UE may be registered to a single 5G PLMN. The UE may establish a RRC connection with the single 5G PLMN.

[0158] In the first implementation and the second implementation wherein UE does not support radio capabilities signalling optimization, the UE may send, to the gNB, information indicating the full UE capability. The UE may send, to the gNB, information indicating the full UE capability due to a registration to a single 5G PLMN (e.g., when registered to a single 5G PLMN). This may trigger the gNB to configure the UE to communicate with the gNB based on the full UE capability.

[0159] If the gNB has not already received the full UE capability from the UE or the AMF, the gNB may receive the full UE capability from the UE or the AMF. The gNB may receive the full UE capability from the AMF over the NGAP interface.

[0160] In the third implementation wherein UE supports radio capabilities signalling optimization, the UE may send, to the gNB, the first identifier identifying the full UE capability. This may trigger the gNB to configure the UE to communicate with the gNB based on the full UE capability. The gNB may obtain the full UE capability determined by the UCMF from the AMF.

[0161] Subsequently, the UE may register to another 5G PLMN. The UE may be simultaneously registered to multiple 5G PLMNs. The UE simultaneously establish RRC connections with multiple 5G PLMNs. This may be triggered to achieve dual steering (e.g., MA PDU session). This may be triggered by an application layer of the UE.

[0162] It will be understood that even though UE may be simultaneously registered to a single 5G PLMN or multiple 5G PLMNs and may have simultaneously establish RRC connections with a single 5G PLMN or multiple 5G PLMNs with multiple 5G (R)ANs, the RRC connections may not simultaneously be active.

[0163] The UE may determine that the UE is simultaneously registered to multiple 5G PLMNs.

[0164] In the first implementation and the second implementation wherein UE does not support radio capabilities signalling optimization, the UE may send, to the gNB, information indicating the reduced UE capability. The UE may send, to the gNB, information indicating the reduced UE capability due to simultaneous registrations to multiple 5G PLMNs. This may trigger the gNB to configure the UE to communicate with the gNB based on the reduced apparatus capability. If the gNB has not already received the reduced UE capability form the UE or the AMF, the gNB may receive the reduced UE capability from the UE or the AMF. The gNB may receive the reduced UE capability from the AMF over the NGAP interface.

[0165] In the third implementation wherein UE supports radio capabilities signalling optimization), the UE may send, to the gNB, the second identifier identifying the reduced UE capability to trigger the gNB to configure the UE to communicate with the gNB based on the reduced apparatus capability. The gNB may obtain the full UE capability determined by the UCMF from the AMF.

[0166] UCMF services may support one or more of the above aspects.

[0167] A Nucmf_Provisioning services may support creating, deleting or updating of UCMF dictionary entry (or entries) for a UE capability ID assigned by a manufacturer.

[0168] A NucmfJJECapabilityManagement service may support assigning the full UE capability and the reduced UE capability when requested by the AMF.

[0169] A Nucmf_UECapabilityManagement_Assign service request may support requesting the full UE capability and the reduced UE capability. If during the registration the AMF identifies that the UE is capable of simultaneous registrations to multiple 5G PLMNs, the AMF may use the Nucmf_UECapabilityManagement_Assign service to request the full UE capability and the reduced UE capability.

[0170] A NucmfJJECapabilityManagement service may support providing the full UE capability and the reduced UE capability to the AMF.

[0171] A NucmfJJECapabilityManagement service may support providing the first identifier identifying the full UE capability and the at least one second identifier identifying the at least one reduced UE capability to the AMF. A NucmfJJECapabilityManagement service may support notifying changes to the full UE radio access capability and the reduced UE radio access capability when subscribed by the AMF.

[0172] Fig. 5 shows a block diagram of a method for managing simultaneous registrations to a single network or multiple networks using a same access type performed by a UE.

[0173] At step 500, the UE sends, to an AMF via a BS, a registration request message indicating that the UE supports multiple simultaneous registrations to a single network or multiple networks using a same access type.

[0174] At step 502, the UE negotiates, with the AMF via the BS, a reduced UE capability to be used by the BS to configure the UE to communicate with the BS when the UE has multiple simultaneous registrations to a single network or to multiple networks using the same access type.

[0175] Fig. 6 shows a block diagram of a method for managing simultaneous registrations to a single network or multiple networks using a same access type performed by an AMF.

[0176] At step 600, the AMF may receive, from a UE via a BS, a registration request message indicating that the UE supports multiple simultaneous registrations to a single network or multiple networks using the same access type.

[0177] At step 602, the AMF may negotiate, with the UE, a reduced UE capability to be used by the BS to configure the UE to communicate with the BS when the UE has multiple simultaneous registrations to a single or to multiple networks using the same access type.

[0178] Fig. 7 shows a schematic representation of non-volatile memory media 700 storing instructions which when executed by a processor allow the processor to perform one or more of the steps of the methods of Fig. 5 and Fig. 6. It is noted that while the above describes example embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

[0179] The embodiments may thus vary within the scope of the attached claims. In general, some embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although embodiments are not limited thereto. While various embodiments may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0180] The embodiments may be implemented by computer software stored in a memory and executable by at least one data processor of the involved entities or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that any procedures, e.g., as in Fig. 5 and Fig. 6, may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

[0181] The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi-core processor architecture, as non-limiting examples.

[0182] Alternatively or additionally, some embodiments may be implemented using circuitry. The circuitry may be configured to perform one or more of the functions and / or method steps previously described. That circuitry may be provided in the base station and / or in the communications device.

[0183] As used in this application, the term “circuitry” may refer to one or more or all of the following:

[0184] (a) hardware-only circuit implementations (such as implementations in only analogue and / or digital circuitry);

[0185] (b) combinations of hardware circuits and software, such as:

[0186] (i) a combination of analogue and / or digital hardware circuit(s) with software / firmware and

[0187] (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as the communications device or base station to perform the various functions previously described; and

[0188] (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0189] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example integrated device. The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of some embodiments However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings will still fall within the scope as defined in the appended claims.

Claims

CLAIMS1. An apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: sending, to a core network function via a base station, a registration request message indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using a same access type; and negotiating, with the core network function via the base station, a reduced apparatus capability to be used by the base station to configure the apparatus to communicate with the base station when the apparatus has multiple simultaneous registrations to a single network or to multiple networks using the same access type.

2. The apparatus of claim 1 , wherein the registration request message explicitly or implicitly indicates that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using the same access type.

3. The apparatus of claim 1 or claim 2, wherein the registration request message comprises multiple simultaneous registrations to a single network or multiple networks using the same access type field that explicitly indicates that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using the same access type; or wherein the registration request message comprises a registration identifier field implicitly indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using the same access type.

4. The apparatus of any of claims 1 to 3, wherein the negotiating, with the core network function via the base station, the reduced apparatus capability comprises: receiving, from the core network function via the base station, a registration accept message indicating the reduced apparatus capability, wherein the reduced apparatus capability is determined by the core network function; andsending, to the core network function via the base station, a registration complete message indicating confirmation of the reduced apparatus capability determined by the core network function.

5. The apparatus of claim 1 , wherein the negotiating, with the core network function via the base station, the reduced apparatus capability comprises: sending, to the core network function via the base station, the registration request message indicating the reduced apparatus capability, wherein the reduced apparatus capability is determined by the apparatus; and receiving, from the core network function via the base station, a registration accept message indicating confirmation of the reduced apparatus capability determined by the apparatus or an alternative reduced apparatus capability, wherein the alternative reduced apparatus capability is determined by the core network function.

6. The apparatus of claim 1 to 5, wherein the at least one memory stores instructions that, when executed by the at least one processor, further cause the apparatus at least to perform: receiving, from the core network function via the base station, a registration accept message indicating a first identifier identifying a full apparatus capability and at least one second identifier identifying at least one reduced apparatus capability.

7. The apparatus of claim 6, wherein the at least one memory stores instructions that, when executed by the at least one processor, further cause the apparatus at least to perform: based on performing a registration to a single network, sending, to the base station, a message comprising the first identifier, the first identifier identifying the full apparatus capability, the message comprising the first identifier configured to cause the base station to configure the apparatus to communicate with the base station based on the full apparatus capability.

8. The apparatus of claim 6 or claim 7, wherein the at least one memory stores instructions that, when executed by the at least one processor, further cause the apparatus at least to perform: based on performing multiple simultaneous registrations to a single network or multiple networks using the same access type, sending, to the base station, a message comprising the at least one second identifier identifying the at least one reduced apparatus capability, the message comprising the at least one second identifier configured to cause the base station to configure the apparatus to communicate with the base station based on the reduced apparatus capability.

9. The apparatus of any of claims 1 to 5, wherein the at least one memory stores instructions that, when executed by the at least one processor, further cause the apparatus at least to perform: based on performing multiple simultaneous registrations to a single network or multiple networks using the same access type, sending, to the base station, a message comprising information indicating a reduced apparatus capability due to multiple registrations to a single network or multiple networks using the same access type, the message comprising the information configured to cause the base station to obtain the reduced apparatus capability from the core network function and to configure the apparatus to communicate with the base station based on the reduced apparatus capability.

10. The apparatus of any of claim 7 to 9, wherein the first identifier identifying the full apparatus capability, the at least one second identifier identifying the at least one reduced apparatus capability or the information indicating a reduced apparatus capability due to multiple registrations to a single network or multiple networks using the same access type is sent in a radio resource control message.

11. The apparatus of any of claims 1 to 10, wherein the reduced apparatus capability comprises a percentage of the full apparatus capability.

12. The apparatus of claim 11 , wherein a full apparatus capability comprises at least one of: a number of component carriers; or a number of cell groups.

13. The apparatus of any of claims 1 to 12, wherein simultaneously registering with a single network or multiple networks using the same access type comprises simultaneously establishing radio connections with a single cellular or multiple networks of the same access type.

14. An apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a user equipment via a base station, a registration request message indicating that the user equipment supports multiple simultaneous registrations to a single network or multiple networks using the same access type; and negotiating, with the user equipment, a reduced user equipment capability to be used by the base station to configure the user equipment to communicate with the base station when the user equipment has multiple simultaneous registrations to a single or to multiple networks using the same access type.

15. The apparatus of claim 14, wherein the negotiating, with the user equipment, a reduced user equipment capability comprises: sending, to the user equipment via the base station, a registration accept message comprising information indicating the reduced user equipment capability, wherein the reduced apparatus capability is determined by the apparatus; and receiving, from the user equipment, a registration complete indicating confirmation of the reduced user equipment capability determined by the apparatus.

16. The apparatus of claim 14, wherein the negotiating, with the user equipment, the reduced user equipment capability comprises:receiving, from the user equipment via the base station, the registration request message indicating the reduced user equipment capability, wherein the reduced apparatus capability is determined by the user equipment; and sending, to the user equipment via the base station, a registration accept message indicating confirmation of the reduced user equipment capability determined by the user equipment or an alternative reduced user equipment capability, wherein the alternative reduced user equipment capability is determined by the apparatus.

17. The apparatus of any of claims 14 to 16, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus at least to perform: sending, to another core network function, a request to determine a full user equipment capability and at least one reduced user equipment capability; and receiving, from the other core network function, a first identifier identifying a full user equipment capability determined by the other core network function, a full user equipment capability determined by the other core network function, at least one second identifier identifying at least one reduced user equipment capability determined by the other core network function and at least one reduced user equipment capability determined by the other core network function.

18. The apparatus of claim 17, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus at least to perform: sending, to the user equipment via the base station and to the base station, the first identifier identifying the full user equipment capability determined by the other core network function and the at least one second identifier identifying the at least one reduced user equipment capability determined by the other core network function.

19. A method comprising: sending, to a core network function via a base station, a registration request message indicating that the apparatus supports multiple simultaneous registrations to a single network or multiple networks using a same access type; andnegotiating, with the core network function via the base station, a reduced apparatus capability to be used by the base station to configure the apparatus to communicate with the base station when the apparatus has multiple simultaneous registrations to a single network or to multiple networks using the same access type.

20. A method comprising: receiving, from a user equipment via a base station, a registration request message indicating that the user equipment supports multiple simultaneous registrations to a single network or multiple networks using the same access type; and negotiating, with the user equipment, a reduced user equipment capability to be used by the base station to configure the user equipment to communicate with the base station when the user equipment has multiple simultaneous registrations to a single or to multiple networks using the same access type. 21 . A computer program comprising computer executable instructions which when run on one or more processors perform the steps of the method of claim 19 or claim 20.

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