Patent Description:
The subject matter disclosed herein relates generally to wireless communications and more particularly relates to radio capability change. In particular, there is disclosed herein a user equipment and a method performed by a user equipment.

The following abbreviations are herewith defined, at least some of which are referred to within the following description: Third Generation Partnership Project ("3GPP"), Positive-Acknowledgment ("ACK"), Binary Phase Shift Keying ("BPSK"), Bandwidth Part ("BWP"), Clear Channel Assessment ("CCA"), Cyclic Prefix ("CP"), Cyclical Redundancy Check ("CRC"), Channel State Information ("CSI"), Common Search Space ("CSS"), Discrete Fourier Transform Spread ("DFTS"), Downlink Control Information ("DCI"), Downlink ("DL"), Downlink Pilot Time Slot ("DwPTS"), Enhanced Clear Channel Assessment ("eCCA"), Enhanced Licensed Assisted Access ("eLAA"), Enhanced Mobile Broadband ("eMBB"), Evolved Node B ("eNB"), European Telecommunications Standards Institute ("ETSI"), Frame Based Equipment ("FBE"), Frequency Division Duplex ("FDD"), Frequency Division Multiple Access ("FDMA"), Frequency Division Orthogonal Cover Code ("FD-OCC"), Guard Period ("GP"), Hybrid Automatic Repeat Request ("HARQ"), Internet-of-Things ("IoT"), Licensed Assisted Access ("LAA"), Load Based Equipment ("LBE"), Listen-Before-Talk ("LBT"), Long Term Evolution ("LTE"), Multiple Access ("MA"), Modulation Coding Scheme ("MCS"), Machine Type Communication ("MTC"), Multiple Input Multiple Output ("MIMO"), Multi User Shared Access ("MUSA"), Narrowband ("NB"), Negative-Acknowledgment ("NACK") or ("NAK"), Next Generation Node B ("gNB"), Non-Orthogonal Multiple Access ("NOMA"), Orthogonal Frequency Division Multiplexing ("OFDM"), Primary Cell ("PCell"), Physical Broadcast Channel ("PBCH"), Physical Downlink Control Channel ("PDCCH"), Physical Downlink Shared Channel ("PDSCH"), Pattern Division Multiple Access ("PDMA"), Physical Hybrid ARQ Indicator Channel ("PHICH"), Physical Random Access Channel ("PRACH"), Physical Resource Block ("PRB"), Physical Uplink Control Channel ("PUCCH"), Physical Uplink Shared Channel ("PUSCH"), Quality of Service ("QoS"), Quadrature Phase Shift Keying ("QPSK"), Radio Resource Control ("RRC"), Random Access Procedure ("RACH"), Random Access Response ("RAR"), Radio Network Temporary Identifier ("RNTI"), Reference Signal ("RS"), Remaining Minimum System Information ("RMSI"), Resource Spread Multiple Access ("RSMA"), Round Trip Time ("RTT"), Receive ("RX"), Sparse Code Multiple Access ("SCMA"), Scheduling Request ("SR"), Single Carrier Frequency Division Multiple Access ("SC-FDMA"), Secondary Cell ("SCell"), Shared Channel ("SCH"), Signal-to-Interference-Plus-Noise Ratio ("SINR"), System Information Block ("SIB"), Synchronization Signal ("SS"), Supplementary Uplink ("SUL"), Transport Block ("TB"), Transport Block Size ("TBS"), Time-Division Duplex ("TDD"), Time Division Multiplex ("TDM"), Time Division Orthogonal Cover Code ("TD-OCC"), Transmission Time Interval ("TTI"), Transmit ("TX"), Uplink Control Information ("UCI"), User Entity/Equipment (Mobile Terminal) ("UE"), Uplink ("UL"), Universal Mobile Telecommunications System ("UMTS"), Uplink Pilot Time Slot ("UpPTS"), Ultra-reliability and Low-latency Communications ("URLLC"), and Worldwide Interoperability for Microwave Access ("WiMAX"). As used herein, "HARQ-ACK" may represent collectively the Positive Acknowledge ("ACK") and the Negative Acknowledge ("NACK"). ACK means that a TB is correctly received while NACK (or NAK) means a TB is erroneously received.

In certain wireless communications networks, an EPC and a 5GC may be deployed without an N26 interface. The N26 interface supports EPS/5GS interworking, thus a UE may simultaneously register with EPS and 5GS, referred to as Dual Registration (DR) mode for interworking between EPS/E-UTRAN and 5GS/NR. However, when a UE operating in DR mode goes out of 5GS/NR coverage and enters an E-UTRA cell providing access to both EPC and 5GC, continuing DR mode would undesirably result in the UE: A) using the same cell to connect to two different CNs and B) having two RRC connections to the same eNB, whereas the one RRC connection is for EPC and the other one to 5GC.

S2-<NUM> is a 3GPP discussion document titled "<NPL> is a technical specification titled "System Architecture for the <NUM> System", this specification covers both roaming and non-roaming scenarios in all aspects, including interworking between 5GS and EPS, mobility within 5GS, QoS, policy control and charging, authentication and in general <NUM> System wide features e.g. SMS, Location Services, Emergency Services.

<CIT> describes an apparatus that: transmits, to a first cell, a first set of capabilities for communication with the first cell; transmits, to the first cell, information associated with a second set of capabilities for communication with a second cell; moving from the first cell to the second cell; and communicating with the second cell based on the transmitted information.

Claim <NUM> defines a user equipment, claim <NUM> defines a method performed by a user equipment. Methods are disclosed for modifying a radio capability. Apparatuses and systems also perform the functions of the methods. The methods may also be embodied in one or more computer program products comprising executable code.

A method for modifying a radio capability includes registering with a first communication system via a radio access network ("RAN") node and detecting a trigger to perform radio capability change for at least one radio access technology ("RAT"). The method includes transitioning the UE state to an idle state and sending a request to the network to update one or more UE radio capabilities while in the idle state.

In the following description, the invention is described with reference to <FIG> and <FIG>, while the description of the remaining figures is provided for illustrative purposes for a better understanding of the invention.

Code for carrying out operations for embodiments may be any number of lines and may be written in any combination of one or more programming languages including an object-oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the "C" programming language, or the like, and/or machine languages such as assembly languages.

The code may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.

The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

Generally, the present disclosure describes systems, methods, and apparatus for modifying a radio capability. In various embodiments, a UE may operate in a Dual Registration ("DR") mode having simultaneous registrations with EPS and 5GS. In some embodiments, the DR mode is used only in networks which do not support interworking via N26 interface.

In a given PLMN, the AMF (in the 5GC) and MME (in the EPC) provide an indication to UEs that EPS-5GS interworking without N26 is supported. This indication may be provided during Initial Registration (in 5GC) or during the Attach procedure (in EPC). Moreover, this indication is valid for the entire Registered PLMN and for PLMNs equivalent to the Registered PLMN. Additionally, the same indication is provided to all UEs served by the same PLMN.

Accordingly, UEs that operate in a PLMN that supports EPS-5GS interworking without N26 (e.g., operable in DR mode) may use this indication to decide whether to register early in the target system. Note that the network does not provide mapped QoS parameters to a UE in DR mode, i.e., if interworking with N26 is not supported.

In various embodiments, the UE provides the following indications to the core network (e.g., AMF or MME) during Initial Attach to EPC or during Registration to 5GC:.

In some embodiments, the UE indicates its support of EPC NAS during the registration procedure with the AMF or its support of 5GC NAS during the attach procedure with the MME. For example, the UE may provide the indication using the "UE Network Capability" parameter. This indication might be used by the AMF/MME to select combo PGW-C+SMF node for EPS-5GS interworking.

Additionally, the UE may indicate that it supports Request Type flag "handover" for PDN connectivity request during the attach procedure in EPC and during initial registration and mobility Registration Update in 5GC. Note that this indication may be used for IP address preservation in the case of interworking without N26.

For interworking without N26, the UE needs to indicate that it is moving from 5GC (or from EPC) so that the MME or AMF does not include "initial attach" indicator to the HSS+UDM. Because the "initial attach" indicator is not included, the HSS+UDM does not cancel the earlier registration of AMF or MME.

<FIG> depicts a wireless communication system <NUM> for suspending services in a first core network while attached to a second core network, according to embodiments of the disclosure. In one embodiment, the wireless communication system <NUM> includes at least one remote unit <NUM>, a first access network <NUM> containing at least one base unit <NUM>, a second access network <NUM> containing at least one base unit <NUM>, wireless communication links <NUM> between remote unit <NUM> and base unit <NUM>, a first core network <NUM>, and a second core network <NUM>. Even though a specific number of remote units <NUM>, access networks <NUM>, <NUM>, base units <NUM>, wireless communication links <NUM>, and core networks <NUM>, <NUM> are depicted in <FIG>, one of skill in the art will recognize that any number of remote units <NUM>, access networks <NUM>, <NUM>, base units <NUM>, wireless communication links <NUM>, and core networks <NUM>, <NUM> may be included in the wireless communication system <NUM>. In various embodiments, the access networks <NUM>, <NUM> may contain one or more WLAN (e.g., Wi-Fi™) access points ("APs"). Here, the first access network <NUM>, second access network <NUM>, first core network <NUM> and second core network <NUM> belong to the same mobile communication network (e.g., the same PLMN).

In one implementation, the wireless communication system <NUM> is compliant with the <NUM> system and the LTE system specified in the 3GPP specifications. More generally, however, the wireless communication system <NUM> may implement some other open or proprietary communication network, for example, WiMAX, among other networks. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architectures or protocols.

In one embodiment, the remote units <NUM> may include computing devices, such as desktop computers, laptop computers, personal digital assistants ("PDAs"), tablet computers, smart phones, smart televisions (e.g., televisions connected to the Internet), smart appliances (e.g., appliances connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), vehicle on-board computers, network devices (e.g., routers, switches, modems), or the like. Moreover, the remote units <NUM> may be referred to as subscriber units, mobiles, mobile stations, users, terminals, mobile terminals, fixed terminals, subscriber stations, UEs, user terminals, a device, or by other terminology used in the art. The remote units <NUM> may communicate directly with one or more of the base units <NUM> via uplink ("UL") and downlink ("DL") communication signals. Furthermore, the UL and DL communication signals may be carried over the wireless communication links <NUM>.

In some embodiments, the remote units <NUM> communicate with a remote host <NUM> (for example, an application server) via a data path that passes through one of the core networks <NUM>, <NUM> and through the data network <NUM>. For example, a remote unit <NUM> may establish a PDU session (or similar data connection) to the data network <NUM> via the first core network <NUM>. The first core network <NUM> then relays traffic between the remote unit <NUM> and the remote host <NUM> using the PDU session. As another example, a remote unit <NUM> may establish a PDN connection to the data network <NUM> via the second core network <NUM>. The second core network <NUM> then relays traffic between the remote unit <NUM> and the remote host <NUM> using the PDN connection.

The base units <NUM> may be distributed over a geographic region. In certain embodiments, a base unit <NUM> may also be referred to as an access terminal, an access point, a base, a base station, a Node-B, an eNB, a gNB, a Home Node-B, a relay node, a device, or by any other terminology used in the art. The base units <NUM> are generally part of a radio access network ("RAN"), such as the first access network <NUM> (e.g., NG-RAN) and/or the second access network <NUM> (e.g., E-UTRAN), that may include one or more controllers communicably coupled to one or more corresponding base units <NUM>. These and other elements of the radio access network are not illustrated, but are well known generally by those having ordinary skill in the art.

The base units <NUM> may serve a number of remote units <NUM> within a serving area, for example, a cell or a cell sector via a wireless communication link <NUM>. The base units <NUM> may communicate directly with one or more of the remote units <NUM> via communication signals. Generally, the base units <NUM> transmit downlink ("DL") communication signals to serve the remote units <NUM> in the time, frequency, and/or spatial domain. Furthermore, the DL communication signals may be carried over the wireless communication links <NUM>. The wireless communication links <NUM> may be any suitable carrier in licensed or unlicensed radio spectrum. The wireless communication links <NUM> facilitate communication between one or more of the remote units <NUM> and/or one or more of the base units <NUM>.

As depicted, the wireless communication system <NUM> includes both a first core network <NUM> and a second core network <NUM> and various interworking network functions for to support interworking between the user plane and certain control plane functions in the first core network <NUM> and the second core network <NUM>. The first core network <NUM> includes an Access and Mobility Management Function ("AMF") <NUM> that is not shared with the second core network <NUM>. Similarly, the second core network <NUM> includes a Mobility Management Entity ("MME") <NUM> and a Serving Gateway ("SGW") <NUM> that are note shared with the first core network <NUM>. However, there is a combined UPF and PGW-user-plane ("UPF+PGW-U") <NUM>, a combined SMF and PGW-control-plane ("SMF+PGW-C") <NUM>, a combined PCF and PCRF ("PCF+PCRF") <NUM>, and a combined HSS and UDM ("HSS+UDM") that support interworking between the first core network <NUM> and second core network <NUM>. Note that the notions "SMF+PGW-C" and "UPF+PGW-U" are used to show that the network functions used for, e.g., PDU Sessions in 5GC and PDN Connections in EPC are common, in case that IP session continuity is required during transfer of PDU Sessions to PDN Connections and vice-versa. Although specific numbers and types of network functions are depicted in <FIG>, one of skill in the art will recognize that any number and type of network functions may be included in the mobile core networks <NUM> and/or <NUM>.

As depicted, the wireless communication system <NUM> includes various network interfaces that facilitate communication among the core network ("CN") elements. For example, a base unit <NUM> (or RAN) may communicate with the AMF <NUM> via the N2 interface and with the UPF+PGW-U <NUM> via the N3 interface. As another example, a base unit <NUM> may communicate with the MME <NUM> via the S1-MME interface and with the SGW via the S1-U interface. Other network interfaces are depicted, including, but not limited to, a N4 interface between the UPF+PGW-U <NUM> and the SMF+PGW-C <NUM>, a N7 interface between the SMF+PGW-C <NUM> and the PCF+PCRF <NUM>, a N8 interface between the AMF <NUM> and the HSS+UDM <NUM>, a N10 interface between the SMF+PGW-C <NUM> and the HSS+UDM <NUM>, a N11 interface between the AMF <NUM> and the SMF+PGW-C <NUM>, a N15 interface between the AMF <NUM> and the PCF+PCRF <NUM>, a S5-U interface between the SGW <NUM> and the UPF+PGW-U <NUM>, a S5-C interface between the SGW <NUM> and the SMF+PGW-C <NUM>, a S6a interface between the MME <NUM> and the HSS+UDM <NUM>, and the S11 interface between the MME <NUM> and the SGW <NUM>.

Although not depicted, the wireless communication system <NUM> may support a N1 interface between the remote unit <NUM> and the AMF <NUM>. Note, however, that there is no network interface between the AMF <NUM> and the MME <NUM> (i.e., no N26 interface). This is because the AMF <NUM> and the MME <NUM> are not communicatively coupled. Accordingly, intersystem handover from the 5GC to EPC (or vice versa) is not supported.

In various embodiments, the remote unit <NUM> may register with a first communication system and indicate (e.g., announce) one or more radio capabilities to the first communication system. Here, the radio capabilities relate to RAT. The remote unit <NUM> later determines to register with a second communication system and updates the one or more UE radio capabilities using a Non-Access Stratum ("NAS") procedure. Here, the first and second communication systems may belong to the same PLMN. In one embodiment, the first communication system includes an EPC and wherein the second communication system comprises a 5GC.

In certain embodiments, the remote unit <NUM> may perform a radio capability exchange towards a base unit <NUM> (e.g., a RAN node). Here, the remote unit <NUM> updates one or more RAT capabilities of the second communication system during the radio capability exchange.

If the remote unit <NUM>'s NG-RAN UE Radio Capability information changes while in CM-IDLE state, the remote unit <NUM> performs the Registration procedure with the Registration type set to Mobility Registration Update indicating "UE Radio Capability Update". When the AMF receives Registration Update Request with "UE Radio Capability Update", it shall delete any UE Radio Capability information that it has stored for the remote unit <NUM>.

If the trigger to change the remote unit <NUM>'s NG-RAN UE Radio Capability information happens when the UE is in CM-CONNECTED state, the remote unit <NUM> first enters CM-IDLE state and then perform the Registration procedure with the Registration type set to Mobility Registration Update indicating "UE Radio Capability Update".

To update the one or more UE radio capabilities, the remote unit <NUM> transitions to a UE idle state, such as the CM-IDLE state. Note that the transition of the "UE state" is in both the remote unit <NUM> and in the network. As described in further detail herein, the transition may be based on explicit signaling. Alternatively, this may be an implicit transition without signaling. and (within the remote unit <NUM>) a NAS entity (e.g., in the NAS layer) instructs an Access Stratum ("AS") entity (e.g., in the AS layer) to modify an AS layer capability. In one embodiment, modifying the AS layer capability comprises disabling a radio capability for a particular radio access technology. In another embodiment, modifying the AS layer capability comprises enabling a radio capability for a particular radio access technology. In certain embodiments, when entering the CM Idle state, the remote unit <NUM> may deactivate a radio resource control ("RRC") idle state, e.g., using NAS signaling and/or RRC signaling. This is an instruction from the NAS layer to the AS layer to transition to RRC idle state. As such, the NAS entity in the remote unit <NUM> may instruct the AS entity to discard (or deactivate) the existing AS context and to modify an AS layer capability for the remote unit <NUM>.

In some embodiments, the remote unit <NUM> updates the one or more UE radio capabilities by having a NAS layer entity initiate a NAS update procedure. One suitable NAS update is the EPS NAS tracking area update procedure. Alternatively, the remote unit <NUM> may initiate the NAS update procedure by sending a 5GS NAS registration request for mobility update.

In other embodiments, a remote unit <NUM> may register with a first communication system via a radio access network ("RAN") node, announce radio capabilities for at least one RAT to the first communication system, and detect a need to change an AS capability of the UE. In response, the remote unit <NUM> may send a request to the network that a particular AS capability be deprecated or disclaimed. Here, the request may be via NAS signaling or RRC signaling. Upon receiving the indication of a deprecated/disclaimed capability (e.g., AS capability), the RAN node (e.g., base unit <NUM>) does not consider the deprecated AS capability (e.g., considers the remote unit <NUM> to not have the particular AS capability).

In certain embodiments, requesting that a particular AS capability be deprecated (disclaimed) includes the remote unit <NUM> indicating that a previously indicated (claimed) RAT capability is deprecated (disclaimed). In certain embodiments, the request that a particular AS capability be deprecated includes an indication that the network does not need to update the UE radio capability. In response to the depreciation indication (disclaiming a RAT capability), the base unit <NUM> (e.g., RAN node) no longer considers the deprecated capability (e.g., considers the remote unit <NUM> to not have the previously indicated RAT capability).

In one embodiment, detecting the need to change the AS capability of the UE comprises determining to register with a second communication system. In other embodiments, other trigger events may require the change in AS capability. Additionally, the remote unit <NUM> may later send a request to the network to abolish the deprecated AS capability.

<FIG> depicts a network architecture <NUM> used for suspending services in a first core network while attached to a second core network, according to embodiments of the disclosure. The network architecture <NUM> may be a simplified embodiment of the wireless communication system <NUM>. As depicted, the network architecture <NUM> includes a UE <NUM> that communicates with a 5GC <NUM> and with an EPC <NUM> via a RAN <NUM>. The UE <NUM> may be one embodiment of the remote unit <NUM>, the 5GC <NUM> may be an embodiment of the first core network <NUM>, and the EPC <NUM> may be an embodiment of the second core network <NUM>. Additionally, the network architecture <NUM> includes multiple core interworking functions <NUM>, such as a SMF/PGW-C interworking function, a UPF/PGW-U interworking functions, etc. Although shared by the 5GC <NUM> and the EPC <NUM>, the HSS+UDM is depicted as separate from the core interworking functions <NUM>.

In the depicted embodiment, the 5GC <NUM> and EPC <NUM> belong to the same PLMN. In various embodiments, the RAN <NUM> broadcasts an indication in the system information (e.g., SIB) that the PLMN supports DR-mode. Here, the UE <NUM> is configured to operate in DR-mode.

<FIG> shows an example of how a UE <NUM> may operate in DR mode, i.e., registered to EPS and 5GC simultaneously. The UE <NUM> may establish PDN Connections in EPS and PDU sessions in 5GS. However, some PDN connection in EPS may not support interworking with 5GS, for example EPS-exclusive connections <NUM> having the S/PGW <NUM> as the anchor point in the user plane. Accordingly, such a PDN connection cannot be transferred to 5GS. Similarly, some PDU Sessions in 5GS may not support interworking with EPS, for example 5GS-exclusive connections <NUM> having the UPF <NUM> as the anchor point in the user plane. Accordingly, such a PDU session cannot be transferred to EPS. Yet another type of PDN connections or PDU session can support interworking between EPS and 5GS, depicted as interworking connections <NUM>, because the anchor point in the control plane (e.g., SMF+PGW-C) for the PDN connection or PDU session is a common entity (e.g., one of the core interworking functions <NUM>) and the anchor point in the user plane (e.g., UPF+PGW-U) is also a common entity.

A UE <NUM> is expected to be able to enable (and disable) capabilities to access 5GS (e.g., 5GC <NUM>). However, at the time of invention there is no access stratum procedure available to accomplish a change of UE capabilities. Thus, the UE <NUM> may rely on upper layer (e.g., NAS) procedures to accomplish such a change. One example of a NAS procedure is the Detach/Re-attach procedure. Note that the UE <NUM> NAS capability is used in the mobility management entity (e.g., MME <NUM> or AMF <NUM>) to select a combined PGW-C+SMF entity (e.g., core interworking function <NUM>) in case of the UE <NUM> supporting both 5GC NAS and EPC NAS. The UE <NUM> NAS capability is distinct from the UE <NUM> radio capability; thus, it should be differentiated between UE <NUM> NAS capability announcement and the UE <NUM> radio capability announcement.

DR mode is intended for interworking between EPS/E-UTRAN and 5GS/NR. A problem occurs when a UE <NUM> operating in DR mode goes out of 5GS/NR coverage and enters an E-UTRA cell providing access to both EPC <NUM> and 5GC <NUM>. The UE <NUM> would end-up in <NUM>) using the same cell to connect to two different CNs (e.g., EPC <NUM> and 5GC <NUM>) and <NUM>) having two RRC connections to the same eNB, whereas the one RRC connection is for EPC <NUM> and the other one to 5GC <NUM>.

In order to avoid such scenario, the UE <NUM> operating in DR mode is not to send its E-UTRA capability to NG-RAN when connected to 5GS/NR to avoid being handed over to 5GC-connected E-UTRA (e.g., RAN <NUM>). This prevents the UE <NUM> from being connected to E-UTRAN/EPC <NUM> and E-UTRA/5GC <NUM> simultaneously using separate RRC connections via a single RAN node (in the RAN <NUM>) as a result of handover. However, 3GPP Release <NUM> ("Rel-<NUM>") leaves unclear which capability the UE <NUM> is to announce when attaching to the EPS/E-UTRAN. Additionally, it is unclear whether the UE <NUM> is to send to the CN its NAS capabilities (5GC NAS and/or EPC NAS capabilities) when disabling/enabling in the AS layer a particular RAT radio capability. Accordingly, current standards do not specify whether the UE <NUM> sends its NR capability to the EPS/E-UTRAN when operating in DR mode.

In various embodiments, the UE <NUM> operating in DR mode is not to send its E-UTRA capability to NG-RAN when connected to 5GS/NR in order to avoid being handed over to 5GC-connected E-UTRA. However, Rel-<NUM> does not provide details about the UE <NUM> behavior while attached/registered to the EPS. In order to avoid the configuration on Dual Connectivity ("DC") with NR when the UE <NUM> is connected to E-UTRA/EPS and the simultaneous use of RRC connection in NR/5GC, in one embodiment, the UE <NUM> does not send its NR capability to E-UTRA when connected to EPS/E-UTRA to avoid being configured in EN-DC mode while also using NR for accessing 5GS/NR.

If the UE <NUM> has been operating in DR mode and the UE <NUM> deregisters from one system, e.g., the UE <NUM> deregisters from the 5GS (this deregistration may be implicit deregistration due to lack of coverage) and the UE <NUM> changes to SR mode with EPS only, then the UE <NUM> may update its radio capability (e.g., to increase radio capability by including the NR capability) to the other system where the UE <NUM> continues to be registered (e.g., in the EPS).

Note that by increasing the radio capability, the already selected core network for existing PDU Sessions or PDN Connections may need to be reselected. For example, if the UE <NUM> is registered to EPS/E-UTRAN and 5GS/NR and the UE <NUM> a) has not indicated NR capability to E-UTRAN and b) has not indicated E-UTRA capability to NR, the corresponding core network node (e.g., MME <NUM>) may have selected user plane nodes (e.g., SGW or UPF) which do not support Dual Connectivity. Accordingly, after increasing the capability, e.g., after the UE <NUM> indicates Dual Connectivity support with multiple RATs, the core network (e.g., MME <NUM>) may need to reselect another user plane node.

When considering UE capabilities, it should be differentiated between NAS layer capabilities and AS layer capabilities. For example, on the NAS layer the UE <NUM> may be capable of DR mode, may be 5GC NAS capable and/or EPC NAS capable, the UE <NUM> may support UP and/or CP CIoT optimizations or NB-IoT capability, to mention just some of the NAS layer capabilities. Additionally, on the AS layer, the UE <NUM> may support different RATs (e.g., UTRAN capable, E-UTRAN capable and/or NR capable) or different frequency bands and other features.

The UE <NUM> needs to differentiate between the following use cases for disabling/enabling <NUM> or <NUM> capability:.

Use Case A: If the UE <NUM> disables <NUM> capability in order to stay attached with EPS only due to e.g., use of feature(s) non-supported in 5GS (e.g., ProSe, MBMS, CIoT optimizations, V2X etc.) but also other use cases can be possible, then the UE <NUM> does not indicate 5GC NAS to the EPC (e.g., MME <NUM>) during NAS (e.g., TAU/Attach) procedure and the UE <NUM> disables the NR capability in the AS layer. With other words, "disabling <NUM> capability" means disabling the 5GC NAS capability and the AS capability (e.g., NR capability).

Similarly, if the UE <NUM> enables the <NUM> capability, then the UE <NUM> indicate 5GC NAS support to the EPC (e.g., MME <NUM>) during NAS (e.g., TAU/Attach) procedure and the UE <NUM> enables the NR capability in the AS layer.

Please note that before disabling the <NUM> capability internally in the UE <NUM>, in order to assure clean state(s) in the network functions in 5GS and avoid unnecessary paging or other signaling, the UE <NUM> may deregister in the 5GS. For example, the UE <NUM> sends a Deregistration Request message indicating an appropriate cause, e.g., moving to other system. If explicit deregistration is performed and after the UE <NUM> receives the Deregistration Accept message, the UE <NUM> transfers to RM-Deregistered state in 5GS and the NAS layer may trigger the AS layer to disable the NR capability and the NAS layer itself disables the 5GC NAS support. The deregistration may be also implicit.

Use Case B: If the UE <NUM> disables <NUM> capability due to e.g., use of DR mode (but also other use cases can be possible), then the UE <NUM> indicates 5GC NAS support to the EPC (e.g., MME <NUM>) but disables only the NR capability in the AS layer. Therefore, in case of change between DR mode and SR mode, the talk is about AS capability change (e.g., RAT capability) and not of <NUM> capability change.

Similarly, if the UE <NUM> enables the <NUM> capability due to use of DR mode, the UE <NUM> indicates 5GC NAS support to the EPC (e.g., MME <NUM>) during NAS (e.g., TAU/Attach) procedure and the UE <NUM> enables the NR capability in the AS layer.

When the DR-capable UE <NUM> is initially registered with the 5GC <NUM> and then discovers LTE coverage, the following steps may be taken. Note that in general the UE <NUM> first registers with a single system e.g., the UE <NUM> performs initial registration to 5GC in a PLMN (see messaging <NUM>). Thus, the UE <NUM> would initially operate in a single registration mode and can announce its radio capability for multiple RATs (e.g., capable of NR and LTE). At some point of time the UE <NUM> determines to perform DR mode.

When the DR-capable UE <NUM> is initially registered with the EPC <NUM> and then discovers NR coverage, the following steps may be taken. Note that in general the UE <NUM> first registers with a single system e.g., the UE <NUM> performs initial attach to EPC <NUM> in a PLMN (see messaging <NUM>). Thus, the UE <NUM> would initially operate in a single registration mode and can announce its radio capability for multiple RATs (e.g., capable of NR and LTE). At some point of time the UE <NUM> determines to perform DR mode.

In various embodiments, when registering with the EPC <NUM>, the UE <NUM> indicates its capabilities, e.g., <NUM> NAS capable, support of "handover" for PDN connectivity, etc. Because the UE <NUM> intends to only use EPS currently (e.g., no NR coverage), the UE <NUM> indicate its E-UTRAN and NR capabilities to the LTE. The EPS/E-UTRAN may decide to configure Dual Connectivity with NR, if NR cell is available. The MME <NUM> indicates to the UE <NUM> that interworking with 5GS is supporting without N26.

While attached to the EPC <NUM>, the UE <NUM> may discover NR coverage and decide to perform DR mode, i.e., to register with 5GS. Per Rel-<NUM>, a UE <NUM> wanting to use one or more EPS functionalities not supported by <NUM> System (e.g., ProSe, MBMS, CIOT optimizations, V2X, etc.), may disable all the related radio capabilities that allow the UE <NUM> to access <NUM> System when in CM-IDLE. Thus, radio capability change may be performed in CM/EMM Idle state, e.g., in order to prevent abrupt termination of services (disruption if active bearers) in CM/EMM Connected state.

Accordingly, the UE <NUM> may transition to CM/EMM Idle state to modify its radio capabilities in the EPS. In various embodiments, the UE <NUM> detects internally based on implementation, configuration (e.g., initiation of DR mode, termination of DR mode, 5GS non-supported feature use, etc.) that radio capability change should be performed in a first registered system. The UE <NUM> first enters CM/EMM Idle state before the NAS layer requests the AS layer to reconfigure the radio capabilities (e.g., increase or decrease radio capabilities). Afterwards the UE <NUM> performs NAS layer signaling to <NUM>) to request update for the UE capability update (e.g., in 5GS or EPS) and <NUM>) to change the registration in the corresponding system. If the UE <NUM> is in CM/EMM Connected and RRC Inactive state for long time, the UE <NUM> may request the deactivation of the RRC Inactive state (or requesting Idle state due to capability change/modification) using the NAS protocol or the RRC protocol.

For initiating 5GS to EPS dual registration operation: if the UE <NUM> is aware that the network supports 5GS-EPS interworking without N26 and the UE <NUM> is dual registration capable and is already registered with the 5GS, when the UE <NUM> determines to attach to a second system (e.g., EPS) in dual registration mode, the UE <NUM> performs the following procedures:.

For initiating EPS to 5GS dual registration operation: if the UE <NUM> is aware that the network supports EPS-5GS interworking without N26 and the UE <NUM> is dual registration capable and is already registered with the EPS, when the UE <NUM> determines to attach to a second system (e.g., 5GS) in dual registration mode, the UE <NUM> performs the following procedures:.

<FIG> depict a first procedure <NUM> for radio capability change of a UE <NUM>, according to embodiments of the disclosure. The first procedure <NUM> involves the UE <NUM>, an NR RAN <NUM>, an LTE RAN <NUM>, the AMF <NUM>, the MME <NUM>, a SMF+PGW-C <NUM>, and the HSS+UDM <NUM>. The steps shown in <FIG> are as described follows:.

The procedure <NUM> begins at <FIG>. In step <NUM>: The UE <NUM> is registered in 5GS (see messaging <NUM>). The UE <NUM> has indicated support of <NUM>) NR+LTE radio capability to the NG-RAN node and <NUM>) EPS NAS capability to the AMF <NUM>. In certain embodiments, the 5GS may configure Dual Connectivity. The 5GS indicates to the UE <NUM> the interworking without N26 is supported.

Step <NUM>: The UE <NUM> detects LTE coverage and determines to initiate dual registration mode of operation. The UE <NUM> decides to change radio capabilities in the currently used system, e.g., in the 5GS/NR (see block <NUM>). The UE <NUM> also determines that it is in CM Connected state and either in RRC Connected or RRC Inactive state (see block <NUM>).

Step <NUM>: If the UE <NUM> is in CM/EMM Connected state, the UE <NUM> may determine to initiate transition to CM Idle state. For this purpose, the UE <NUM> may perform one of the following actions:.

The UE <NUM> NAS layer may query the RRC layer about the RRC state (i.e., RRC Connected or RRC Inactive state). If the RRC state is RRC Inactive, the UE <NUM> may send a NAS indication to the AMF <NUM> to request disablement of the RRC Inactive state. For example, the UE <NUM> can send a Registration Request message having a type of Mobility Registration Update with indication 'transfer to Idle state' or 'disable RRC Inactive state' or a similar indication). In addition, the UE <NUM> may indicate the reason for transition to Idle state, e.g., UE <NUM> needs to change AS layer capabilities.

The UE <NUM> may send NAS Deregistration Request message to the AMF <NUM> with an indication that the Deregistration is due to UE <NUM> radio capability change and an indication that re-registration is (e.g., soon) expected (see messaging <NUM>). In such case, the AMF <NUM> may initiate a deregistration procedure, for example the deregistration procedure described in 3GPP TS <NUM> version <NUM>. At the end of the deregistration procedure, the UE <NUM> state in the AMF <NUM> is RM-Deregistered. The AMF <NUM> may however keep the security context downloaded previously from the UDM/UDR because the AMF <NUM> may expect re-registration soon.

The UE <NUM> may send an RRC message to the NG-RAN node (e.g., gNB) to indicate to disable the RRC Inactive state (see messaging <NUM>). For this purpose, the UE <NUM> may perform the RRC resume procedure with an indication to disable RRC Inactive state.

Step <NUM>: AMF <NUM> to NR RAN <NUM>: The AMF <NUM> initiates N2 procedure for disabling the RRC Inactive state, if the RRC state is RRC Inactive (see messaging <NUM>). An existing N2 message or a new N2 message can be used to request the NG-RAN node to disable the RRC Inactive state. If the AMF <NUM> is not aware about the RRC state, the AMF <NUM> may request the RAN node to release the UE context of the UE <NUM>.

Optionally, the AMF <NUM> may include an indication that the release is not urgent and can be performed upon UE Inactivity. For example, the AMF <NUM> may use N2 UE Context Release Request (release cause value, delay tolerant release), where the cause value may indicate the reason for releasing the UE context, e.g., UE radio capability change. The 'delay tolerant release' indicates to the RAN node that the RRC connection can be release upon UE Inactivity (e.g., short inactivity of <NUM> seconds or <NUM> seconds), so that the release is not urgent.

Step <NUM>: The NG-RAN node performs procedure for RRC Idle state transition, e.g., after Inactivity timer expires (see messaging <NUM>).

Step <NUM>: UE <NUM> in CM/EMM Idle or RM Deregistered state: the NAS layer performs AS layer modification (see block <NUM>). For example, the AS layer may increase or decrease radio capabilities, e.g., by including or excluding a RAT capability.

The procedure <NUM> continues at <FIG>. In step 6a, UE <NUM> to CN (e.g., AMF <NUM>): (Note, the UE <NUM> may be in CM/EMM Idle state) UE <NUM> initiates NAS procedure (e.g., Registration procedure) to indicate change of its radio capabilities (e.g., to reduce radio capabilities by excluding the radio capabilities of a RAT or to increase the radio capabilities) (see messaging <NUM>). The UE <NUM> may use Registration Request message having a type of Mobility Registration Update and including an indication that radio capability change is required. This indication can be called e.g., 'UE <NUM> radio capability' or 'UE <NUM> radio capability change' or any other similar parameter name can be used. This 'UE <NUM> radio capability change' indication causes at the AMF <NUM> to perform the steps 6b and/or 6c. The AMF <NUM> may reply to the UE <NUM> with Registration Accept message including an appropriate cause value of accepting or rejecting the requested radio capability change.

In step 6b: The AMF <NUM> deletes the already stored UE <NUM> radio capabilities received previously from the NG-RAN node (see block <NUM>).

In step 6c: The AMF <NUM> initiates N2 procedure to inform the RAN node that the AS capabilities are changed (see messaging <NUM>). The AMF <NUM> does not include already stored UE <NUM> radio capabilities. The AMF <NUM> may send UE <NUM> context to the RAN node, so that the RAN node can know that the AS capabilities are changed.

In step 6d: The NG-RAN node initiates RRC procedure to query the UE <NUM> radio capabilities (see messaging <NUM>). The UE <NUM> announces/sends its radio capabilities by excluding the E-UTRA capabilities, since the AS layer has been instructed so by the NAS layer.

If the UE <NUM> is in CM/EMM Connected state and the RRC Inactive state (please note that the AMF <NUM> may be aware about the activation of RRC Inactive state if the AMF <NUM> has subscribed to RRC state notification as described in TS <NUM> clause <NUM>. <NUM> "N2 Notification procedure") and the indication 'UE <NUM> radio capability change' is included, the AMF <NUM> may decide first to disable the RRC Inactive state.

If the UE <NUM> is in RM-Deregistered state, the UE <NUM> does not need to include 'UE <NUM> radio capability' indication, as the AMF <NUM> would have already deleted the previously stored UE <NUM> radio capabilities. The UE <NUM> performs normal Registration procedure with type Initial registration.

Step <NUM>: The UE <NUM> initiates Attach procedure in the EPC/E-UTRAN system (see block <NUM>).

Step <NUM>: If the UE <NUM> is registered to another system (e.g., using DR mode and already registered to 5GS), the UE <NUM> announces (or sends) its AS layer capability (i.e., the E-UTRA capability) to the eNB, but the UE <NUM> excludes the NR radio capability (see messaging <NUM>).

Note that steps <NUM>-<NUM> (grouped in the dotted line box (A)) show one solution option for explicit UE-initiated signaling for disabling the RRC Inactive state or for transition to CM Idle state. Another option is to integrate the RRC Inactive state disablement procedure in the Registration procedure for UE capability change, e.g., as shown in step <NUM>. Also, note that <FIG> shows an example signaling flow for the case where the UE <NUM> is registered first to the 5GS and the UE <NUM> attempts a DR mode operation with EPS later.

For initiating EPS to 5GS dual registration case: analogically to the above, just exchanging the EPS and 5GS. In other embodiments, similar signaling flow is also applicable in the scenario where the UE <NUM> is first attached in the EPS and the UE <NUM> attempts a DR mode operation with 5GS. In such case, the UE <NUM> would first need to decrease its radio capabilities in the EPS, i.e., to disable the NR capability, and then the UE <NUM> attempts Registration procedure to the 5GS via NR. In such embodiments, UE <NUM> preform at least steps <NUM> and/or <NUM> towards the EPS (e.g., eNB and/or MME <NUM>) to request Idle state or disable the RRC Inactive state in the E-UTRAN.

<FIG> shows a second procedure <NUM> for radio capability change of a UE <NUM>, according to embodiments of the disclosure. The second procedure <NUM> involves the UE <NUM>, an NR RAN <NUM>, an LTE RAN <NUM>, the AMF <NUM>, the MME <NUM>, a SMF+PGW-C <NUM>, and the HSS+UDM <NUM>. The steps shown in <FIG> are as described follows:.

The UE <NUM> sends a request to the network (e.g., an indication in NAS message to the mobility serving node (e.g., MME <NUM> or AMF <NUM>)) that a particular AS capability (e.g., RAT capability) should not be considered (i.e., the RAT capability is deprecated/disclaimed). In such case UE <NUM> radio capability is decreased without sending the full radio capability to the network. In similar way, the UE <NUM> can at any time endorse the use of the deprecated RAT capability, i.e., the UE <NUM> can increase its capability without sending the full radio capability, but instead abolishing/canceling previously deprecated capability. This solution may be applicable to any of the UE <NUM> states, e.g., CM/EMM Connected or CM/EMM Idle.

For example, the UE <NUM>, which is attached to EPS and having announces E-UTRA and NR capability to the E-UTRAN, indicates in NAS signaling to the MME <NUM> that the NR shall not be considered for dual connectivity. The UE <NUM> triggers such signaling based on starting a DR-mode and registering with 5GS/NR. Then the MME <NUM> indicates to the RAN node (e.g., eNB) that dual connectivity with NR shall not be configured. Upon the signaling from the MME <NUM>, the eNB learns that UE <NUM>'s radio capability has not changed, but the eNB shall not consider configuring the DC with NR for this UE <NUM>.

If the UE <NUM> changes from DR mode to SR mode and stays attached to a first system (e.g., EPS) or other trigger events for increasing the radio capability occur, the UE <NUM> sends an indication in NAS signaling to the MME <NUM> that the deprecated RAT capability (e.g., NR capability) may be endorsed, i.e., the deprecated RAT capability can be considered for dual connectivity. With other words, the NAS signaling 'activates' a deprecated RAT (e.g., NR) capability.

Step <NUM>: The UE <NUM> is registered in 5GS (see messaging <NUM>). The UE <NUM> has indicated support of <NUM>) NR+LTE radio capability to the NG-RAN node and <NUM>) EPS NAS capability to the AMF <NUM>. 5GS can configure dual connectivity (DC). The 5GS indicates to the UE <NUM> the interworking without N26 is supported.

Step <NUM>: The UE <NUM> detects LTE coverage and determines to initiate dual registration mode of operation (see block <NUM>). The UE <NUM> decides to change radio capabilities in the currently used system, e.g., in the 5GS/NR. The UE <NUM> may determine that it is in CM Connected state and RRC Inactive state.

Step <NUM>: The UE <NUM> initiates NAS procedure towards the core network (e.g., AMF <NUM>) indicating that a particular AS capability (e.g., RAT capability) is deprecated (see messaging <NUM>). With other words this RAT capability should not be considered for dual connectivity (DC) configuration. For example, the UE <NUM> may send a Registration Request message including an indication that the E-UTRA capability should not be considered in the system.

Step 3a: From CN to RAN: (if the UE <NUM> is in CM/EMM Connected state,) the AMF <NUM> initiates UE <NUM> Context updated procedure towards the NG-RAN node to indicate that a particular UE <NUM> radio capability is deprecated (see messaging <NUM>). For example, the AMF <NUM> indicates to the NG-RAN node that the NR capability is deprecated, i.e., dual connectivity with E-UTRAN should not be configured.

Step 3b: After the RAN node acknowledges the reception (and possibly processing of the requested to deprecate RAT capability) (see messaging <NUM>). The Core network (e.g., the AMF <NUM>) may respond to the registration request of step <NUM> by sending an appropriate cause value whether the request from step <NUM> is accepted or rejected.

Step <NUM>: The NG-RAN node performs RRC reconfiguration to disable the UE <NUM> radio measurements in the indicated RAT (e.g., in the E-UTRA) (See messaging <NUM>).

Step <NUM>: The UE <NUM> announces E-UTRA capability to the eNB, but the UE <NUM> excludes the NR radio capability (see block <NUM>).

In summary, the <FIG> shows a method for deprecating a particular AS capability, e.g., using NAS signaling, without the need to send the complete UE <NUM> radio capabilities to the network (e.g., to the RAN node). Please note that <FIG> shows an example signaling flow for the case where the UE <NUM> is registered first to the 5GS and the UE <NUM> attempts a DR mode operation with EPS later.

In another embodiment, it is also possible that the UE <NUM> abolishes the deprecated AS capability at some point, i.e., the UE <NUM> enables (or endorses) the deprecated AS capability. For example, the UE <NUM> sends a NAS message (e.g., Registration Request message or TAU request message) including an indication that a deprecated AS capability (e.g., deprecated RAT capability) should be enabled. Then the core network (e.g., MME <NUM> or AMF <NUM>) updates the RAN node via S1 or N2 interface with an indication to enable the deprecated AS capability. The RAN node can perform RRC reconfiguration to configure the UE <NUM> to report measurements for previously deprecated RAT.

In another embodiment related to the <FIG>, similar signaling flow is also applicable in the scenario where the UE <NUM> is first attached in the EPS and the UE <NUM> attempts a DR mode operation with 5GS. In such case, the UE <NUM> would first deprecate particular AS capabilities in the EPS, i.e., to disable the NR capability, and then the UE <NUM> attempts Registration procedure to the 5GS via NR.

In yet another embodiment related to the <FIG>, the network may determine to deprecate a particular AS capability (e.g., RAT capability) without explicit indication by the UE <NUM>. For example, this can be performed including signaling exchange via HSS+UDM <NUM>. When a UE <NUM> registered to 5GS decides to use DR mode and attempts to attach to the EPS (e.g., MME <NUM>), the MME <NUM> updates the HSS+UDM <NUM> indicating that the UE <NUM> is attaching for DR mode of operation. The HSS+UDM <NUM> informs the AMF <NUM> that the UE <NUM> is now in addition attached to the EPS. Then the AMF <NUM> initiates signaling towards the RAN node (e.g., gNB) to indicate that the E-UTRA capability is deprecated. The AMF <NUM> assumes that the UE <NUM> has sent E-UTRA capability to gNB because the E-UTRA is a native RAT in NG-RAN.

In certain embodiments, the UE <NUM> may determine to not send radio measurement reports to the RAN node including measurements from a RAT which the UE <NUM> uses in another system. For example, if the UE <NUM> has announced NR capabilities to the E-UTRAN node and the UE <NUM> is configured to perform measurements of NR cell, and the UE <NUM> is in DR mode with the 5GC/NR, the UE <NUM> determines to not report radio measurements of NR cell even if the UE <NUM> can measure signal from NR cell. This can be done by either signaling some special or reserved values; that indicate to the network that the UE <NUM> is neither measuring NR cell nor is it interested in being handed over to NR cell; or, by not making any measurements at all. In any case, the UE <NUM> shall report only especial or Zero signal level (RSRP for example) if periodic reporting is configured. The UE <NUM> may reject measurement gaps configured for such purposes. Alternatively, a UE <NUM> may directly indicate to the RAN network that it is not interested in measuring or being handed over to an NR cell, by way of a new RRC signaling just for example.

In certain embodiments, if the UE <NUM> is operating in DR mode, but the UE <NUM> is only attached/ registered with the first system (e.g., 5GS) without established PDN connection or PDU Session, then the UE <NUM> continues to use its dual radio capabilities, i.e., the UE <NUM> uses the first system radio capability (e.g., NR capabilities) to the second system (e.g., EPS). Before the UE <NUM> initiates PDN connection establishment or PDU Session establishment in the first system, the UE <NUM> performs radio capability update procedure in the second system in order to exclude the radio capabilities of the first system (e.g., exclude NR capability).

Please note that the use cases for triggering radio capability change can be various. In some embodiments the assumption is the enablement or disablement of DR mode, however other use cases are possible. For example, the modem capabilities (e.g., mobile equipment (ME) capability) changes due to hardware modification like attaching or detaching hardware to the terminal. Another example is that the user can enable or disable terminal capability via the phone's menu.

<FIG> depicts a user equipment apparatus <NUM> that may be used for UE power control for multiple UL carriers, according to embodiments of the disclosure. The user equipment apparatus <NUM> may be one embodiment of the remote unit <NUM> and/or UE <NUM>, described above. Furthermore, the user equipment apparatus <NUM> may include a processor <NUM>, a memory <NUM>, an input device <NUM>, an output device <NUM>, a transceiver <NUM> for communicating with one or more base units <NUM>.

As depicted, the transceiver <NUM> may include a transmitter <NUM> and a receiver <NUM>. The transceiver <NUM> may also support one or more network interfaces <NUM>, such as the Uu interface used to communicate with a gNB, or another suitable interface for communicating with a RAN (e.g., first access network <NUM> and/or second access network <NUM>). In some embodiments, the input device <NUM> and the output device <NUM> are combined into a single device, such as a touchscreen. In certain embodiments, the user equipment apparatus <NUM> may not include any input device <NUM> and/or output device <NUM>.

In various embodiments, the processor <NUM> registers with a first communication system via the RAN node. In some embodiments, registering with the first communication system includes indicating one or more UE radio capabilities for at least one RAT to the first communication system.

The processor <NUM> detects a trigger to perform radio capability change for at least one radio access technology ("RAT"). In some embodiments, detecting a trigger to perform radio capability change includes determining to perform dual-registration with a second communication system. In some embodiments, detecting a trigger to perform radio capability change includes determining to register with a second communication system, the second system different than the first system. In certain embodiments, the first and second communication systems belonging to the same PLMN. In certain embodiments, the first communication system includes an evolved packet core network and wherein the second communication system includes a 3GPP fifth generation core network.

The processor <NUM> transitions the UE state of the user equipment apparatus <NUM> to an idle state. In various embodiments, transitioning the UE state to an idle state includes entering a Connection Management ("CM") Idle state on the NAS layer. In such embodiments, a NAS entity instructs a UE Access Stratum ("AS") entity to discard/deactivate the existing AS context and instructs the UE AS entity to modify an AS layer capability for the user equipment apparatus <NUM> in response to entering the CM Idle state. In certain embodiments, modifying the AS layer capability includes disabling a UE capability for a particular radio access technology. In certain embodiments, modifying the AS layer capability includes enabling a UE capability for a particular radio access technology. In certain embodiments, entering the CM Idle state includes deactivating the AS context to enter a radio resource control ("RRC") idle state using, e.g., NAS signaling and/or RRC signaling.

The processor <NUM> requests the network (e.g., the first communication system) to update one or more UE radio capabilities while in the idle state. In some embodiments, requesting to update one or more UE radio capabilities includes performing a radio capability exchange towards the RAN node.

In various embodiments, requesting to update one or more UE radio capabilities includes using a NAS signaling procedure to indicate the update of one or more UE radio capabilities. In one embodiment, requesting to update one or more UE radio capabilities includes sending a NAS registration request. Here, the NAS registration has a mobility registration type and indicates the updated one or more UE radio capabilities. In another embodiment, requesting to update one or more UE radio capabilities includes sending a tracking area update ("TAU") request. Here, the TAU request indicates the updated one or more UE radio capabilities.

In some embodiments, detecting a trigger to perform radio capability change includes detecting a need to change an Access Stratum ("AS") capability of the user equipment apparatus <NUM>. In such embodiments, requesting to update one or more UE radio capabilities includes requesting that a particular AS capability be deprecated, wherein the RAN node does not consider the particular AS capability. In certain embodiments, requesting that a particular AS capability be deprecated includes sending one of a NAS message and an RRC message to a core network.

In certain embodiments, requesting that a particular AS capability be deprecated includes indicating that a previously indicated RAT capability is deprecated. In certain embodiments, requesting that a particular AS capability be deprecated includes indicating that the core network does not need to update the UE radio capability. In some embodiments, detecting the need to change the AS capability of the user equipment apparatus <NUM> includes determining to register with a second communication system. In certain embodiments, the processor <NUM> further sends a request to the network to abolish the deprecated AS capability.

In some embodiments, the memory <NUM> stores data related to modifying a radio capability. For example, the memory <NUM> may store radio capabilities, registrations, and the like. In certain embodiments, the memory <NUM> also stores program code and related data, such as an operating system or other controller algorithms operating on the remote unit <NUM>.

The transceiver <NUM> includes at least transmitter <NUM> and at least one receiver <NUM>. One or more transmitters <NUM> may be used to provide UL communication signals to a base unit <NUM>. Similarly, one or more receivers <NUM> may be used to receive DL communication signals from the base unit <NUM>, as described herein. Although only one transmitter <NUM> and one receiver <NUM> are illustrated, the user equipment apparatus <NUM> may have any suitable number of transmitters <NUM> and receivers <NUM>. Further, the transmitter(s) <NUM> and the receiver(s) <NUM> may be any suitable type of transmitters and receivers. In one embodiment, the transceiver <NUM> includes a first transmitter/receiver pair used to communicate with a mobile communication network over licensed radio spectrum and a second transmitter/receiver pair used to communicate with a mobile communication network over unlicensed radio spectrum.

As discussed above, the transceiver <NUM> communicates with one or more network functions of a mobile communication network via one or more access networks. The transceiver <NUM> operates under the control of the processor <NUM> to transmit messages, data, and other signals and also to receive messages, data, and other signals. For example, the processor <NUM> may selectively activate the transceiver (or portions thereof) at particular times in order to send and receive messages. The transceiver <NUM> may include one or more transmitters <NUM> and one or more receivers <NUM>. In certain embodiments, the one or more transmitters <NUM> and/or the one or more receivers <NUM> may share transceiver hardware and/or circuitry. For example, the one or more transmitters <NUM> and/or the one or more receivers <NUM> may share antenna(s), antenna tuner(s), amplifier(s), filter(s), oscillator(s), mixer(s), modulator/demodulator(s), power supply, and the like.

In various embodiments, the transceiver <NUM> is configured to communication with 3GPP access network(s) and/or non-3GPP access network(s). In some embodiments, the transceiver <NUM> implements modem functionality for the 3GPP access network(s) and/or the non-3GPP access network(s). In one embodiment, the transceiver <NUM> comprises a chip that implements multiple logical transceivers using different communication protocols or protocol stacks, while using common physical hardware. For example, the transceiver <NUM> may include one application-specific integrated circuit ("ASIC") which includes the function of first transceiver and second transceiver for accessing networks of different RATs. In other embodiments, the transceiver <NUM> comprises separate transceiver hardware for accessing networks of different RATs.

<FIG> is a schematic flow chart diagram illustrating one embodiment of a method <NUM> for modifying a radio capability, according to embodiments of the disclosure. In some embodiments, the method <NUM> is performed by a UE, such as the remote unit <NUM>, the UE <NUM>, and/or the user equipment apparatus <NUM>. In certain embodiments, the method <NUM> may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method <NUM> includes registering <NUM> with a first communication system via a radio access network ("RAN") node. In some embodiments, registering with the first communication system includes indicating one or more UE radio capabilities for at least one RAT to the first communication system.

The method <NUM> includes detecting <NUM> a trigger to perform radio capability change for at least one radio access technology ("RAT"). In some embodiments, detecting <NUM> a trigger to perform radio capability change includes determining to register with a second communication system, the second system different than the first system. In certain embodiments, the first and second communication systems belonging to the same PLMN. In certain embodiments, the first communication system includes an evolved packet core network and wherein the second communication system includes a 3GPP fifth generation core network.

The method <NUM> includes transitioning <NUM> the UE state to an idle state. In various embodiments, transitioning <NUM> the UE state to an idle state includes entering a Connection Management ("CM") Idle state on the NAS layer entity of the UE. In certain embodiments, entering the CM Idle state includes deactivating the AS context (e.g., using NAS signaling or RRC signaling) to enter an RRC idle state.

The method <NUM> includes sending <NUM> a request to the network to update one or more UE radio capabilities while in the idle state. The method <NUM> ends. In some embodiments, sending <NUM> the request to update one or more UE radio capabilities includes using a Non-Access Stratum ("NAS") signaling procedure to indicate the update of one or more UE radio capabilities. In one embodiment, sending <NUM> the request to update one or more UE radio capabilities includes sending a NAS registration request, said request having a mobility registration type and indicating the updated one or more UE radio capabilities. In another embodiment, sending <NUM> the request to update one or more UE radio capabilities includes sending a tracking area update request, said request indicating the updated one or more UE radio capabilities.

In certain embodiments, detecting <NUM> a trigger to perform radio capability change includes determining to perform dual-registration with a second communication system. In such embodiments, sending <NUM> the request to update one or more UE radio capabilities includes performing a radio capability exchange towards the RAN node.

In some embodiments, detecting <NUM> a trigger to perform radio capability change includes detecting a need to change an Access Stratum ("AS") capability of the UE, wherein sending <NUM> the request to update one or more UE radio capabilities includes requesting that a particular AS capability be deprecated, wherein the RAN node does not consider the particular AS capability. In certain embodiments, detecting the need to change the AS capability of the UE includes determining to register with a second communication system.

In certain embodiments, requesting that a particular AS capability be deprecated includes sending a NAS message or an RRC message to a core network. In certain embodiments, requesting that a particular AS capability be deprecated includes indicating that a previously indicated RAT capability is deprecated. In certain embodiments, requesting that a particular AS capability be deprecated includes indicating that the core network does not need to update the UE radio capability.

Disclosed herein is a first apparatus for modifying a radio capability. The first apparatus may be implemented by the remote unit <NUM>, the UE <NUM>, and/or the user equipment apparatus <NUM>. The first apparatus includes a processor and a transceiver that communicates with a RAN node. The processor registers with a first communication system via the RAN node. The processor detects a trigger to perform radio capability change for at least one radio access technology ("RAT") and transitions a UE state of the apparatus to an idle state. The processor further sends a request to the first communication system to update one or more UE radio capabilities while in the idle state.

In some embodiments, registering with the first communication system includes indicating one or more UE radio capabilities for at least one RAT to the first communication system. In some embodiments, detecting a trigger to perform radio capability change includes determining to perform dual-registration with a second communication system. In such embodiments, sending the request to update one or more UE radio capabilities includes performing a radio capability exchange towards the RAN node, wherein the processor updates one or more UE radio access technology capabilities of the second communication system during the radio capability exchange.

In various embodiments, sending the request to update one or more UE radio capabilities includes using a Non-Access Stratum ("NAS") signaling procedure to indicate the update of one or more UE radio capabilities. In one embodiment, sending the request to update one or more UE radio capabilities includes sending a NAS registration request. Here, the NAS registration has a mobility registration type and indicates the updated one or more UE radio capabilities. In another embodiment, sending the request to update one or more UE radio capabilities includes sending a tracking area update ("TAU") request. Here, the TAU request indicates the updated one or more UE radio capabilities.

In some embodiments, detecting a trigger to perform radio capability change includes determining to register with a second communication system, the second system different than the first system. In certain embodiments, the first and second communication systems belonging to the same PLMN. In certain embodiments, the first communication system includes an evolved packet core network and wherein the second communication system includes a 3GPP fifth generation core network.

In various embodiments, transitioning the UE state to an idle state includes entering a Connection Management ("CM") Idle state on the Non-Access Stratum ("NAS") layer. In such embodiments, the first apparatus includes a NAS entity that instructs a UE Access Stratum ("AS") entity to discard (or deactivate) the existing AS context and instructs the UE AS entity to modify an AS layer capability for the apparatus in response to entering the CM Idle state. In certain embodiments, modifying the AS layer capability includes disabling a UE capability for a particular radio access technology. In certain embodiments, modifying the AS layer capability includes enabling a UE capability for a particular radio access technology. In certain embodiments, entering the CM Idle state includes deactivating the AS context to enter a radio resource control ("RRC") idle state using, e.g., NAS signaling and/or RRC signaling.

In some embodiments, detecting a trigger to perform radio capability change includes detecting a need to change an Access Stratum ("AS") capability of the apparatus. In such embodiments, sending the request to update one or more UE radio capabilities includes requesting that a particular AS capability be deprecated, wherein the RAN node does not consider the particular AS capability. In certain embodiments, requesting that a particular AS capability be deprecated includes sending wither a NAS message or an RRC message to a core network.

In certain embodiments, requesting that a particular AS capability be deprecated includes indicating that a previously indicated RAT capability is deprecated. In certain embodiments, requesting that a particular AS capability be deprecated includes indicating that the core network does not need to update the UE radio capability. In some embodiments, detecting the need to change the AS capability of the apparatus includes determining to register with a second communication system. In certain embodiments, the processor further sends a request to the network to abolish the deprecated AS capability.

Disclosed herein is a first method for modifying a radio capability. The first method may be performed by a UE, such as the remote unit <NUM>, the UE <NUM>, and/or the user equipment apparatus <NUM>. The first method includes registering with a first communication system via a radio access network ("RAN") node and detecting a trigger to perform radio capability change for at least one radio access technology ("RAT"). The first method includes transitioning a UE state to an idle state and sending a request to the first communication system to update one or more UE radio capabilities while in the idle state.

In some embodiments, registering with the first communication system includes indicating one or more UE radio capabilities for at least one RAT to the first communication system. In certain embodiments, detecting a trigger to perform radio capability change includes determining to perform dual-registration with a second communication system. In such embodiments, sending the request to update one or more UE radio capabilities includes performing a radio capability exchange towards the RAN node. Here, the first method may also include updating one or more UE radio access technology capabilities of the second communication system during the radio capability exchange.

In some embodiments, sending the request to update one or more UE radio capabilities includes using a Non-Access Stratum ("NAS") signaling procedure to indicate the update of one or more UE radio capabilities. In one embodiment, sending the request to update one or more UE radio capabilities includes sending a NAS registration request, said request having a mobility registration type and indicating the updated one or more UE radio capabilities. In another embodiment, sending the request to update one or more UE radio capabilities includes sending a tracking area update request, said request indicating the updated one or more UE radio capabilities.

In various embodiments, transitioning to an idle state includes entering a Connection Management ("CM") Idle state on the Non-Access Stratum ("NAS") layer of the UE. In such embodiments, the first method may include a NAS entity instructing a UE Access Stratum ("AS") entity to discard/deactivate the existing AS context and instructing the UE AS entity to modify an AS layer capability for the UE in response to entering the CM Idle state. In certain embodiments, modifying the AS layer capability includes disabling a UE capability for a particular radio access technology. In certain embodiments, modifying the AS layer capability includes enabling a UE capability for a particular radio access technology. In certain embodiments, entering the CM Idle state includes deactivating the AS context to enter a radio resource control ("RRC") idle state using, e.g., NAS signaling and/or RRC signaling.

In some embodiments, detecting a trigger to perform radio capability change includes detecting a need to change an Access Stratum ("AS") capability of the UE, wherein sending the request to update one or more UE radio capabilities includes requesting that a particular AS capability be deprecated, wherein the RAN node does not consider the particular AS capability. In certain embodiments, detecting the need to change the AS capability of the UE includes determining to register with a second communication system. Here, the first method may include sending a request to the network to abolish the deprecated AS capability.

Claim 1:
A user equipment, UE, (<NUM>) comprising:
a transceiver (<NUM>) arranged to communicate with a radio access network, RAN, node; and
a processor (<NUM>) arranged to register with a first communication system via the RAN node;
detect a trigger to perform radio capability update for at least one radio access technology, RAT, the trigger comprising the UE starting a Dual Registration mode and registering with a second communication system;
transition the UE (<NUM>) to an idle state; and
send a request to the first communication system to update UE radio capabilities while in the idle state, the request indicating that any already stored UE radio capabilities are to be updated.