Methods, user equipment, and non-transitory computer readable media for lower layer triggered mobility for recovery from radio link failure

Abstract

Lower-layer triggered mobility for recovery from radio link failures. A method is disclosed comprising receiving a first Radio Resource Control (RRC) reconfiguration message, which includes: a conditional reconfiguration field including a conditional reconfiguration and a lower-layer triggered mobility (LTM) configuration field including an LTM configuration, the conditional reconfiguration including an RRC reconfiguration field containing a second RRC reconfiguration message, wherein the second RRC reconfiguration message includes a master key update field and wherein the LTM configuration field is excluded from the second RRC reconfiguration message, the LTM configuration including an attempt LTM handover field and an RRC reconfiguration field including a third RRC reconfiguration message, wherein the conditional reconfiguration field, the LTM configuration field and the master key update field are excluded from the third RRC reconfiguration message, detecting a radio link failure of a primary cell group (MCG), determining a selected cell based on the radio link failure of the MCG, and performing an LTM cell handover to the selected cell based on the LTM configuration.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 734,533, filed December 16, 2024, which is incorporated herein by reference in its entirety. Technical Field

[0003] This application generally relates to lower-layer triggered mobility for recovery from radio link failures. Background Technology

[0004] As wireless communication systems have evolved, numerous methods for handling radio link failures have become possible. However, many of these methods possess different and similar capabilities and rely on different and similar configuration information. It would be desirable to provide a solution that allows for flexible configuration information for various radio link failure recovery methods while ensuring that the UE performs appropriate actions related to the configuration information. In some cases, it would be desirable to provide constraints on the content of the configuration information to suitably tailor it for its associated radio link recovery method. Furthermore, it would be desirable for the UE to select the appropriate radio link recovery method based on the configuration information it receives. Summary of the Invention

[0005] Various aspects of the invention are set forth in the claims.

[0006] One or more embodiments may provide an apparatus, a computer-readable medium, a non-transitory computer-readable medium, a computer program product, and / or a method for receiving a first Radio Resource Control (RRC) reconfiguration message, the first RRC reconfiguration message including: a conditional reconfiguration field including a conditional reconfiguration and an LTM configuration field including a lower-layer triggered mobility (LTM) configuration, the conditional reconfiguration including an RRC reconfiguration field including a second RRC reconfiguration message, wherein the second RRC reconfiguration message includes a master key update field and wherein the LTM configuration field is excluded from the second RRC reconfiguration message, the LTM configuration including an attempt LTM handover field and an RRC reconfiguration field including a third RRC reconfiguration message, wherein the conditional reconfiguration field, the LTM configuration field, and the master key update field are excluded from the third RRC reconfiguration message, detecting a radio link failure of a primary cell group (MCG), determining a selected cell based on the radio link failure of the MCG, and performing an LTM cell handover to the selected cell based on the LTM configuration.

[0007] In at least one example embodiment, conditional reconfiguration includes attempting to conditionally reconfigure a field.

[0008] In at least one example embodiment, the conditional reconfiguration field instructs the UE to attempt to apply a second RRC reconfiguration message after a radio link failure in the MCG.

[0009] In at least one example embodiment, the execution of LTM cell handover is based on a preference to perform LTM cell handover relative to the application of a second RRC reconfiguration message.

[0010] One or more example embodiments further perform a determination that security updates are not required, wherein the LTM cell handover is performed based on the determination that security updates are not required.

[0011] One or more example embodiments further perform the determination of the LTM configuration including the attempt to LTM handover field, wherein the execution of LTM cell handover is based on the determination of the LTM configuration including the attempt to LTM handover field.

[0012] One or more embodiments may provide an apparatus, a computer-readable medium, a non-transitory computer-readable medium, a computer program product, and / or a method for receiving a first Radio Resource Control (RRC) reconfiguration message, the first RRC reconfiguration message including: a conditional reconfiguration field including conditional reconfiguration, and an LTM configuration field including lower-layer triggered mobility (LTM) configuration, the conditional reconfiguration including an attempt conditional reconfiguration field, and an RRC reconfiguration field including a second RRC reconfiguration message, wherein the second RRC reconfiguration message includes a master key update field, and wherein the LTM configuration field is excluded from the second RRC reconfiguration message, the LTM configuration including an attempt LTM handover word. The process includes a segment and an RRC reconfiguration field that includes a third RRC reconfiguration message, wherein the conditional reconfiguration field, LTM configuration field, and master key update field are excluded from the third RRC reconfiguration message; detecting radio link failures in the primary cell group (MCG); determining the selected cell based on the radio link failures in the MCG; determining whether the LTM configuration includes an attempt to LTM handover field; if the LTM configuration includes an attempt to LTM handover field, performing an LTM cell handover to the selected cell based on the LTM configuration; determining whether the conditional reconfiguration includes an attempt to conditional reconfiguration field; and if the conditional reconfiguration includes an attempt to conditional reconfiguration field, applying a second RRC reconfiguration message to the selected cell.

[0013] In at least one example embodiment, the conditional reconfiguration field instructs the UE to attempt to apply a second RRC reconfiguration message after a radio link failure in the MCG.

[0014] One or more example embodiments further perform an LTM cell handover to the selected cell based on the LTM configuration, in cases where the LTM configuration includes an attempt to LTM handover field and the conditional reconfiguration includes an attempt to conditional reconfiguration field, instead of applying a second RRC reconfiguration message to the selected cell.

[0015] One or more example embodiments further include, in cases where the LTM configuration includes an attempt to LTM handover field and the conditional reconfiguration includes an attempt to conditional reconfiguration field, determining whether a security update is required, wherein: if a security update is not required, an LTM cell handover to the selected cell based on the LTM configuration is performed, and if a security update is required, a second RRC reconfiguration message is applied to the selected cell.

[0016] In at least one example embodiment, the first Radio Resource Control (RRC) reconfiguration message includes configuration information for the MCGMCG.

[0017] In at least one example embodiment, since the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration, the conditional reconfiguration field, the LTM configuration field, and the master key update field are excluded from the third RRC reconfiguration message.

[0018] In at least one example embodiment, the LTM configuration field is excluded from the second RRC reconfiguration message because the second RRC reconfiguration message is included in the conditional reconfiguration RRC reconfiguration field.

[0019] In at least one example embodiment, the second RRC reconfiguration message includes a conditional reconfiguration field.

[0020] In at least one example embodiment, conditional reconfiguration specifies configuration information for reconfiguring candidate cells.

[0021] In at least one example embodiment, LTM configuration is configuration information used to perform LTM cell handover.

[0022] In at least one example embodiment, the master key update field includes information related to changes in the master security key.

[0023] In at least one example embodiment, the attempt to LTM handover field instruction instructs the UE to attempt to perform an LTM cell handover after a radio link failure in the MCG.

[0024] In at least one example embodiment, the second RRC reconfiguration message includes a Data Radio Bearer (DRB) configuration that includes a Dual Active Protocol Stack (DAPS) configuration field.

[0025] In at least one example embodiment, the DAPS configuration field indicates that the DRB configured by the DRB configuration is a DAPS bearer.

[0026] In at least one example embodiment, the DAPS configuration field is excluded from the third RRC reconfiguration message.

[0027] In at least one example embodiment, the DAPS configuration field is excluded from the third RRC reconfiguration message because the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration.

[0028] In at least one example embodiment, the second RRC reconfiguration message includes a radio link control (RLC) bearer configuration that includes rebuilding the RLC field.

[0029] In at least one example embodiment, the Rebuild RLC field instruction instructs the UE to rebuild the RLC when applying the RLC bearer configuration.

[0030] In at least one example embodiment, the rebuild RLC field is excluded from the third RRC reconfiguration message.

[0031] In at least one example embodiment, the rebuild RLC field is excluded from the third RRC reconfiguration message because the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration.

[0032] One or more example embodiments further perform the determination that the selected cell is associated with an LTM configuration, wherein the execution of LTM cell handover is based on the determination that the selected cell is associated with an LTM configuration.

[0033] In at least one example embodiment, determining that the selected cell is associated with the LTM configuration includes determining that the selected cell is an LTM candidate cell corresponding to an LTM candidate field included in the LTM configuration.

[0034] One or more example embodiments further perform the determination that the selected cell is associated with a conditional reconfiguration, wherein a second RRC reconfiguration message is applied to the selected cell based on the determination that the selected cell is associated with a conditional configuration.

[0035] In at least one example embodiment, determining that a selected cell is associated with a conditional configuration includes determining that the selected cell is a candidate cell corresponding to a candidate cell indicated in the conditional configuration.

[0036] In at least one example embodiment, the second RRC reconfiguration message includes a Multiple Radio Access Technology Dual Connectivity (MRDC) subcell group configuration field indicating the configuration of the MRDC subcell group, and the MRDC subcell group configuration field indicating the configuration of the MRDC subcell group is excluded from the third RRC reconfiguration message.

[0037] In at least one example embodiment, the third RRC reconfiguration message includes an MRDC subcell group configuration field indicating release.

[0038] In at least one example embodiment, since the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration, the MRDC subcell group configuration field indicating the configuration of the MRDC subcell group is excluded from the third RRC reconfiguration message.

[0039] In at least one example embodiment, performing an LTM cell handover includes releasing multiple private RRC configurations and multiple public RRC configurations.

[0040] In at least one example embodiment, performing an LTM cell handover includes preserving the radio bearer configuration.

[0041] In at least one example embodiment, performing an LTM cell handover includes retaining the Radio Link Control (RLC) bearer configuration.

[0042] In at least one example embodiment, preserving the RLC bearer configuration includes preserving the logical channel identity of the RLC bearer configured by the RLC bearer configuration. Attached Figure Description

[0043] For a more complete understanding of embodiments of the present invention, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0044] Figure 1 This is a block diagram illustrating an apparatus according to at least one example embodiment.

[0045] Figure 2 This is a block diagram illustrating a wireless communication system according to at least one example embodiment.

[0046] Figure 3 This is a diagram illustrating a protocol stack according to at least one example embodiment.

[0047] Figure 4 This is an interactive diagram illustrating activities associated with RRC reconfiguration according to at least one example embodiment.

[0048] Figure 5 This is a flowchart illustrating the activities associated with switching to a selected cell according to at least one example embodiment.

[0049] Figure 6 This is a flowchart illustrating the activities associated with switching to a selected cell according to at least one example embodiment.

[0050] Figure 7 This is a flowchart illustrating the activities associated with switching to a selected cell according to at least one example embodiment, and

[0051] Figure 8 This is a flowchart illustrating the activities associated with switching to a selected cell according to at least one example embodiment. Detailed Implementation

[0052] By referring to the attached figures Figures 1 to 8 To understand the embodiments of the present invention and its potential advantages.

[0053] Some embodiments will now be described more fully below with reference to the accompanying drawings, which illustrate some, but not all, of the embodiments. Various embodiments of the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. The same reference numerals throughout refer to the same elements. As used herein, the terms “data,” “content,” “information,” and similar terms are used interchangeably to refer to data that can be transmitted, received, and / or stored according to embodiments of the invention. Therefore, the use of any such terms should not be construed as limiting the spirit and scope of the embodiments of the invention.

[0054] Additionally, as used herein, the term "circuitry" refers to (a) a purely hardware circuit implementation (e.g., an implementation in an analog circuit system and / or a digital circuit system); (b) a combination of circuitry and (one or more) computer program products, including software and / or firmware instructions stored on one or more computer-readable storage media, which work together to enable a device to perform one or more functions described herein; and (c) a circuit, such as, for example, (one or more) microprocessors or portions thereof, which requires software or firmware to operate, even if the software or firmware is not physically present. This definition of "circuitry" applies to all uses of the term herein, including in any claim. As another example, as used herein, the term "circuitry" also includes an implementation comprising one or more processors and / or portions thereof, along with accompanying software and / or firmware. As yet another example, as used herein, the term "circuitry" also includes, for example, a baseband integrated circuit or application processor integrated circuit for a mobile phone, or a similar integrated circuit in a server, cellular network device, other network device, and / or other computing device.

[0055] As defined herein, “non-transitory computer-readable medium” refers to physical media (e.g., volatile or non-volatile memory devices) and can be distinguished from “transitory computer-readable medium”, which refers to electromagnetic signals.

[0056] Figure 1 This is a block diagram illustrating a device such as electronic device 100 according to at least one example embodiment. However, it should be understood that the electronic device illustrated and described below is merely illustrative of electronic devices that can benefit from embodiments of the invention and should therefore not be considered as limiting the scope of the invention. While electronic device 100 is illustrated for illustrative purposes and will be described below, other types of electronic devices can readily employ embodiments of the invention. Electronic device 100 may be a network node, such as a user equipment (UE) or base station, and / or may be a personal digital assistant (PDA), pager, mobile computer, desktop computer, television, gaming device, laptop computer, tablet computer, media player, camera, video recorder, mobile phone, global positioning system (GPS) device, automobile, kiosk, electronic table, and / or any other type of electronic system. Furthermore, the device of at least one example embodiment need not be an entire electronic device, but may be a component or group of components of an electronic device in other example embodiments. For example, the device may be an integrated circuit, a collection of integrated circuits, and / or the like.

[0057] Furthermore, devices can readily employ embodiments of the invention, regardless of their intended purpose of providing mobility. In this regard, while embodiments of the invention may be described in connection with mobile applications, it should be understood that embodiments of the invention can be used in conjunction with a variety of other applications both within and outside the mobile communications industry. For example, the device may be at least part of a large-screen television, electronic table, kiosk, automobile, and / or similar non-portable devices.

[0058] In at least one example embodiment, electronic device 100 includes a processor 110 and a memory 140. The processor 110 can be any type of processor, controller, embedded controller, processor core, and / or the like. In at least one example embodiment, the processor 110 utilizes computer program code to cause the device to perform one or more actions. The memory 140 may include volatile memory, such as volatile random access memory (RAM) including a cache for temporary data storage, and / or other memory such as embedded and / or removable non-volatile memory. Non-volatile memory may include EEPROM, flash memory, and / or the like. The memory 140 may store any of a plurality of pieces of information and data. Electronic device 100 may use this information and data to implement one or more functions of electronic device 100, such as the functions described herein. In at least one example embodiment, the memory 140 includes computer program code such that the memory and the computer program code are configured to work with the processor to cause the device to perform one or more actions described herein.

[0059] Electronic device 100 may further include transceiver 120. In at least one example embodiment, transceiver 120 is coupled to one or more antennas 130. In at least one example embodiment, processor 110 provides signals to transceiver 120 and / or receives signals from transceiver 120. Signals may include signaling information according to a communication interface standard, user voice, received data, user-generated data, and / or the like. Transceiver 120 may operate using one or more air interface standards, communication protocols, modulation types, and access types. With the aid of the illustration, the electronic transceiver 120 can operate according to second-generation (2G) wireless communication protocols such as IS-136 (Time Division Multiple Access (TDMA)), Global System for Mobile Communications (GSM) and IS-95 (Code Division Multiple Access (CDMA)), according to third-generation (3G) wireless communication protocols such as Universal Mobile Telecommunications System (UMTS), CDMA2000, Wideband CDMA (WCDMA) and Time Division Synchronous CDMA (TD-SCDMA), and / or according to fourth-generation (4G) wireless communication protocols such as LTE, fifth-generation (5G) protocols such as New Radio (NR) wireless networking protocols such as 802.11, short-range radio protocols such as Bluetooth, and / or the like.

[0060] Processor 110 may include components such as circuit systems for implementing audio, video, communication, navigation, logic functions, and / or similar functions, as well as embodiments of the invention for implementing one or more functions, such as those described herein. For example, processor 110 may include components such as digital signal processor devices, microprocessor devices, various analog-to-digital converters, digital-to-analog converters, processing circuit systems, and other support circuitry for performing various functions, including one or more functions, such as those described herein. The device may perform control and signal processing functions of electronic device 100 between these devices, depending on their respective capabilities. Therefore, processor 110 may include the functionality to encode and interleave messages and data prior to modulation and transmission. Processor 110 may additionally include an internal voice encoder and may include an internal data modem. Furthermore, processor 110 may include the functionality to operate one or more software programs, which may be stored in memory and, among other things, enable processor 110 to implement at least a portion of an embodiment, including one or more functions, such as those described herein. For example, processor 110 may operate connectivity programs, such as a conventional internet browser. The connectivity program can allow electronic device 100 to transmit and receive Internet content, such as location-based content and / or other web page content, according to, for example, Transmission Control Protocol (TCP), Internet Protocol (IP), User Datagram Protocol (UDP), Internet Message Access Protocol (IMAP), Post Office Protocol (POP), Simple Mail Transfer Protocol (SMTP), Wireless Application Protocol (WAP), Hypertext Transfer Protocol (HTTP) and / or the like.

[0061] Electronic device 100 may include a user interface for providing output and / or receiving input. Electronic device 100 may include output devices, such as audio output devices like ringers, headphones, and speakers; tactile output devices like vibration transducers, electrically deformable surfaces, and electrically deformable structures; and visual output devices like displays and / or lights. Electronic device may include input devices such as light sensors, proximity sensors, microphones, touch sensors, force sensors, buttons, keypads, motion sensors, magnetic field sensors, cameras, and / or the like. In at least one example embodiment, the device receives an input indication. The device may receive indications from sensors, drivers, separate devices, and / or the like. Information indicating input may include information conveying the indication of input, information indicating aspects of the input that indicate the occurrence of the indication, and / or the like.

[0062] Figure 2An example of a wireless communication system 200 according to at least one exemplary embodiment is illustrated. The wireless communication system 200 includes one or more base stations 202, a core network 203, and one or more user equipments (UEs) such as UE 201 and / or UE 204. In some examples, the wireless communication system 200 may be a Long Term Evolution (LTE), LTE-Advanced (LTE-A) network, a New Radio (NR) network, etc. In some cases, the wireless communication system 200 may support enhanced broadband communication, ultra-reliable (i.e., mission-critical) communication, low-latency communication, and communication with low-cost and low-complexity devices. To improve the reliability of some communications (e.g., ultra-reliable low-latency communication (URLLC) packets), the wireless communication system 200 may be configured to generate and transmit duplicate packets. In such a duplication system, a transmitting device (e.g., base station 202, UE 201, or UE 204) may duplicate packets. The original packets and duplicate packets may be transmitted to a receiving device (e.g., base station 202, UE 201, or UE 204). Transmitting multiple packets containing the same information can improve the likelihood that the receiving device will receive information included in multiple packets.

[0063] One or more base stations 202 can wirelessly communicate with one or more UEs (e.g., UE 201 or UE 204) via one or more base station antennas. Each base station 202 can provide communication coverage for a corresponding geographical coverage area. The communication link in the wireless communication system 200 can include uplink transmission from the UE to the base station 202, or downlink transmission from the base station 202 to the UE. Depending on various technologies, control information and data can be multiplexed on the uplink channel or the downlink channel. For example, time division multiplexing (TDM), frequency division multiplexing (FDM), or hybrid TDM-FDM technologies can be used to multiplex control information and data on the downlink channel. In some examples, control information transmitted during the transmission time interval (TTI) of the downlink channel can be distributed in a cascaded manner between different control areas (e.g., between a common control area and one or more UE-specific control areas).

[0064] Multiple UEs can be distributed across the wireless communication system 200 times, and each UE can be stationary or mobile. A UE can also be referred to as a mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, mobile phone, user agent, mobile client, client, or some other suitable terminology. A UE can also be a cellular phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, tablet computer, laptop computer, cordless phone, personal electronic device, handheld device, personal computer, wireless local loop (WLL) station, Internet of Things (IoT) device, Internet of Everything (IoE) device, machine-type communication (MTC) device, appliance, vehicle, or the like.

[0065] In some cases, a UE may also be able to communicate directly with other UEs using sidelink communication (e.g., using peer-to-peer (P2P) or device-to-device (D2D) protocols). For example, Figure 2 An example of such communication between UE 201 and UE 204 is provided. One or more UEs in a group utilizing sidelink communication may be within the cell's coverage area. Other UEs in such a group may be outside the cell's coverage area or otherwise unable to receive transmissions from base station 202. In some cases, a group of UEs communicating via sidelink communication may utilize a one-to-many (1:M) system, where each UE transmits to every other UE in the group. In some cases, base station 202 facilitates resource scheduling for sidelink communication. In other cases, sidelink communication is implemented independently of base station 202.

[0066] In some cases, UE 204 can operate as a relay UE for UE 201. For example, instead of communicating directly with base station 202, UE 204 can be configured to operate as a relay, allowing UE 201 to communicate with base station 202 directly through UE 204. For example, UE 204 can operate as a Layer 2 (L2) UE-to-Network (U2N) relay.

[0067] Some UEs, such as MTC or IoT devices, can be low-cost or low-complexity devices that can provide automated communication between machines, i.e., machine-to-machine (M2M) communication. M2M or MTC can refer to data communication technologies that allow devices to communicate with each other or with base stations without human intervention. For example, M2M or MTC can refer to communication from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application, which can then utilize that information or present it to people interacting with it. Some UEs can be designed to collect information or enable automated machine behavior. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based billing.

[0068] In some cases, MTC devices can operate at reduced peak rates using half-duplex (one-way) communication. MTC devices can also be configured to enter a power-saving "deep sleep" mode when not engaged in active communication. In some cases, MTC or IoT devices can be designed to support mission-critical functions, and the wireless communication system can be configured to provide ultra-reliable communication for these functions.

[0069] Base station 202 can communicate with core network 203 and with one or more other base stations. For example, the base station may interface with core network 203 via a come-backhaul link (e.g., S1, etc.). Base stations may communicate with each other directly or indirectly (e.g., via core network 203) via other backhaul links (e.g., X2, etc.). The base station may perform radio configuration and scheduling for communicating with the UE or may operate under the control of a base station controller (not shown). In some examples, base station 202 may be a macro cell, small cell, hotspot, and / or the like. The base station may also be referred to as an evolved NodeB (NB), such as an eNB, gNB, and / or the like.

[0070] Base station 202 can connect to core network 203 via the S1 interface. The core network can be an evolved packet core (EPC), which may include at least one mobility management entity (MME), at least one serving gateway (S-GW), and at least one packet data network (PDN) gateway (P-GW). The MME can be a control node handling signaling between UE 201 and the EPC. All user Internet Protocol (IP) packets can be transmitted through the S-GW, which itself can connect to the P-GW. The P-GW can provide IP address allocation and other functions. The P-GW can connect to network operator IP services. Operator IP services may include the Internet, intranet, IP Multimedia Subsystem (IMS), and packet-switched (PS) streaming services.

[0071] Core network 203 can provide user authentication, access authorization, tracking, IP connectivity, and other access, routing, or mobility functions. At least some network devices, such as base station 202, may include sub-components such as access network entities, which may be examples of access node controllers (ANCs). Each access network entity can communicate with multiple UEs through multiple other access network transport entities, each of which may be an example of a smart radio headend or a transmit / receive point (TRP). In some configurations, the various functions of each access network entity or base station may be distributed across various network devices (e.g., radio headends and access network controllers) or consolidated into a single network device (e.g., base station 202).

[0072] Wireless communication system 200 can operate in the ultra-high frequency (UHF) frequency region using a frequency band from 700 MHz to 2600 MHz (2.6 GHz), although some networks (e.g., wireless local area networks (WLANs)) can use frequencies as high as 4 GHz. This region can also be referred to as the decimeter band because the wavelength varies in length from approximately one decimeter to one meter. UHF waves can propagate primarily through the line of sight and can be blocked by buildings and environmental features. However, the waves can penetrate walls sufficiently to provide service to UEs located indoors. Compared to transmissions using the lower frequencies (and longer waves) of the high frequency (HF) or very high frequency (VHF) portions of the spectrum, UHF wave transmission is characterized by smaller antennas and shorter ranges (e.g., less than 100 km). In some cases, wireless communication system 200 can also utilize the extremely high frequency (EHF) portion of the spectrum (e.g., from 30 GHz to 300 GHz). This region can also be referred to as the millimeter band because the wavelength varies in length from approximately one millimeter to one centimeter. Therefore, EHF antennas may be even smaller and more closely spaced than UHF antennas. In some cases, this can facilitate the use of antenna arrays within the UE 201 (e.g., for directional beamforming). However, EHF transmissions may suffer from even greater atmospheric attenuation and shorter range than UHF transmissions.

[0073] Therefore, the wireless communication system 200 can support millimeter-wave (mmW) communication between the UE and the base station. Devices operating in the mmW or EHF bands can have multiple antennas to allow beamforming. That is, the base station 202 can use multiple antennas or antenna arrays for beamforming operations for directional communication with the UE 201. Beamforming (also known as spatial filtering or directional transmission) is a signal processing technique that can be used at the transmitter (e.g., the base station) to shape and / or guide the overall antenna beam in the direction of the target receiver (e.g., the UE). This can be achieved by combining elements in an antenna array such that signals transmitted at a specific angle undergo constructive interference while other signals undergo destructive interference.

[0074] A cell can operate within the total channel bandwidth. In some cases, it may be desirable for a cell to have a configuration involving different portions of the total channel bandwidth, such as Bandwidth Parts (BWPs). Such a configuration takes into account that the configuration information used by the cell is common within a BWP and differs across different BWPs. For example, it may be desirable for a cell to have two BWPs, allowing time-frequency resources to be configured differently between the two BWPs. Furthermore, such a configuration considers a smooth transition between the configuration information used for a BWP and the configurations used for different BWPs, only by indexing the correct BWP and referencing the indexed BWP. Thus, each BWP can have its own configuration information for managing multiple aspects of communication, such as physical layer resources, MAC resources, RRC resources, etc.

[0075] Multiple-input multiple-output (MIMO) wireless systems use a transmission scheme between a transmitter (e.g., a base station) and a receiver (e.g., a UE), where both the transmitter and receiver are equipped with multiple antennas. Some portions of the wireless communication system 200 may use beamforming. For example, base station 202 may have an antenna array with multiple rows and columns of antenna ports that the base station can use for beamforming in its communication with UE 201. Signals can be transmitted multiple times in different directions (e.g., each transmission can be beamformed differently). The mmW receiver (e.g., the UE) can attempt multiple beams (e.g., antenna subarrays) when receiving synchronization signals.

[0076] In some cases, the antennas of base station 202 or UE 201 may be located within one or more antenna arrays, which can support beamforming or MIMO operation. One or more base station antennas or antenna arrays may be juxtaposed at an antenna assembly such as an antenna tower. In some cases, the antennas or antenna arrays associated with base station 202 may be located in different geographical locations. Base station 202 may use multiple antennas or antenna arrays for beamforming operations for directional communication with UE 201.

[0077] In some cases, the wireless communication system 200 may be a packet-based network operating according to a layered protocol stack. In the user plane, communication at the bearer or PDCP layer may be IP-based. In some cases, the RLC layer may perform packet fragmentation and reassembly for communication over logical channels. The Media Access Control (MAC) layer may perform priority processing and multiplexing logical channels into transport channels. The MAC layer may also provide retransmissions at the MAC layer using Hybrid Automatic Repeat Request (HARQ) to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide the establishment, configuration, and maintenance of RRC connections between UE 201 and network equipment or core network 203 supporting user plane data radio bearers. At the physical (PHY) layer, transport channels may be mapped to physical channels.

[0078] In LTE or NR, time intervals can be expressed as multiples of a basic time unit (which could be a sampling period of Ts = 1 / 30,720,000 seconds). Time resources can be organized based on radio frames of 10 ms in length (Tf = 307200Ts), identified by System Frame Numbers (SFNs) ranging from 0 to 1023. Each frame can comprise ten 1 ms subframes numbered from 0 to 9. Subframes can be further divided into two 0.5 ms slots, each containing six or seven modulation symbol periods (depending on the length of the cyclic prefix pre-added to each symbol). Excluding the cyclic prefix, each symbol contains 2048 sampling periods. In some cases, a subframe can be the smallest scheduling unit, also known as a Time Interval (TTI). In other cases, the TTI can be shorter than a subframe or can be dynamically selected (e.g., in short TTI bursts or in selected component carriers using short TTIs).

[0079] A resource element can consist of one symbol period and one subcarrier (e.g., a 15 kHz frequency range). A resource block can contain twelve consecutive subcarriers in the frequency domain and, for each normal cyclic prefix in an Orthogonal Frequency Division Multiplexing (OFDM) symbol, can contain seven consecutive OFDM symbols (one time slot) in the time domain, or 84 resource elements. The number of bits carried by each resource element can depend on the modulation scheme (the configuration of symbols selectable during each symbol period). Therefore, the more resource blocks the UE receives and the more sophisticated the modulation scheme, the higher the data rate may be.

[0080] The wireless communication system 200 can support operation on multiple cells or carriers, a feature that may be referred to as carrier aggregation (CA) or multi-carrier operation. A carrier may also be referred to as a component carrier (CC), layer, channel, etc. The terms "carrier," "component carrier," "cell," and "channel" are used interchangeably herein. The UE 201 can be configured with multiple downlink CCs and one or more uplink CCs for carrier aggregation. Carrier aggregation can be used in conjunction with both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0081] In some cases, wireless system 200 may utilize both licensed and unlicensed radio spectrum bands. For example, wireless system 200 may employ LTE Licensed Assisted Access (LTE-LAA) or LTE Unlicensed (LTE U) radio access technologies or NR technologies in unlicensed bands such as the 5 GHz Industrial, Scientific, and Medical (ISM) band. When operating in unlicensed radio spectrum bands, wireless devices such as base station 202 and UE 201 may employ a Listen-After-Talk (LBT) procedure to ensure the channel is clear before transmitting data. In some cases, operation in unlicensed bands may be based on a CA configuration combined with CC operation in licensed bands. Operation in unlicensed spectrum may include downlink transmission, uplink transmission, or both. Duplexing in unlicensed spectrum may be based on FDD, TDD, or a combination of both.

[0082] Figure 3 This is a diagram illustrating a protocol stack 300 according to at least one example embodiment. Figure 3 The examples provided are merely examples and do not necessarily limit the scope of the claims.

[0083] In at least one example embodiment, the physical (PHY) layer 304 provides information transmission services to higher layers using a physical channel. The PHY layer 304 may be connected to the media access control (MAC) layer 303 located at a higher layer via a transport channel. Data may be transmitted between the MAC layer 303 and the PHY layer 304 via the transport channel. Data may be transmitted between the physical layer on the transmitting side and the physical layer on the receiving side via the physical channel. The physical channel uses time and frequency as radio resources. In some cases, an orthogonal frequency division multiple access (OFDMA) scheme is used to modulate the physical channel in the downlink, and a single-carrier frequency division multiple access (SC-FDMA) scheme is used to modulate the physical channel in the uplink.

[0084] In at least one example embodiment, MAC layer 303 provides services to the higher-level Radio Link Control (RLC) layer 302 via a logical channel. The second-layer RLC layer 302 supports reliable data transmission. The functionality of RLC layer 302 can be implemented by functional blocks of MAC layer 303. Packet Data Convergence Protocol (PDCP) layer 301 performs header compression to reduce unnecessary control information for efficient transmission of Internet Protocol (IP) packets, such as IP version 4 (IPv4) or IP version 6 (IPv6) packets, in a radio interface with relatively low bandwidth.

[0085] In at least one example embodiment, PDCP layer 301 is implemented by PDCP entities that perform various actions of the PDCP layer. Thus, the operating network node includes one or more PDCP entities for performing PDCP layer activities. In operation, the PDCP entities receive data for transmission from higher layers in PDCP Service Data Units (SDUs). The PDCP entities perform various operations on the PDCP SDUs received from higher layers for transmission, such as header compression, uplink data compression, integrity protection, encryption, and / or the like. The PDCP entities perform these operations on the received PDCP SDUs to generate PDCP Packet Data Units (PDUs), which are then transmitted by sending the PDCP SDUs to lower layers for transmission.

[0086] In at least one example embodiment, RLC layer 302 is implemented by RLC entities that perform various actions of the RLC layer. Thus, the operating network node includes one or more RLC entities for performing RLC layer activities. In operation, the RLC entity receives data for transmission from a higher layer in an RLC SDU. The RLC entity performs various operations on the RLC SDU received from the higher layer for transmission, such as header compression, uplink data compression, integrity protection, encryption, and / or the like. The RLC entity performs these operations on the received RLC SDU to generate an RLC PDU, which is then transmitted by sending the RLC SDU to a lower layer for transmission.

[0087] In at least one example embodiment, MAC layer 303 is implemented by MAC entities that perform various actions of the MAC layer. Thus, the operating network node includes one or more MAC entities for performing MAC layer activities. In operation, the MAC entity receives data for transmission from a higher layer in a MAC SDU. The MAC entity performs various operations on the MAC SDU received from the higher layer for transmission, such as header compression, uplink data compression, integrity protection, encryption, and / or the like. The MAC entity performs these operations on the received MAC SDU to generate a MAC PDU, which is then transmitted by sending the MAC SDU to a lower layer for transmission.

[0088] In some cases, it might be desirable for the base station to provide configuration parameters to the UE. For example, it might be desirable for the UE to receive configuration parameters that allow the UE to configure multiple layers, such as those related to... Figure 3 The layers under discussion. In such a case, the UE receives an RRC reconfiguration message from the base station and applies the RRC reconfiguration message to set various parameters of multiple layers that conform to the configuration information included in the RRC reconfiguration message. In at least one example embodiment, the RRC reconfiguration message is an RRCReconfiguration message.

[0089] Figure 4 This is an interaction diagram illustrating activities associated with Radio Resource Control (RRC) reconfiguration according to at least one example embodiment. In at least one example embodiment, there is an interaction with... Figure 4 A set of operations corresponding to an activity. A device, for example... Figure 1 The electronic device 100, or a portion thereof, can utilize the set of operations. The device may include components for performing such operations, such components including, for example, […]. Figure 1 The processor 110. In an example embodiment, by means of, for example, having computer code Figure 1 Memory such as memory 140 is used to transform the device, for example Figure 1 The electronic device 100, the computer code being configured to work with a processor, for example Figure 1 The processor 110 works together to enable the device to perform Figure 4 A set of operations. UE 401 can be... Figure 2 UE 201 or UE 204, and base station 402 can be Figure 2 Base station 202.

[0090] In at least one example embodiment, UE 401 receives an RRC reconfiguration message 403 from base station 402. In at least one example embodiment, upon receiving the RRC reconfiguration message, the UE applies the RRC reconfiguration message by releasing various configurations and applying the configurations included in the RRC reconfiguration message. When applying the RRC reconfiguration message, UE 401 sends an RRC reconfiguration complete message 404 to base station 402.

[0091] In at least one example embodiment, the received RRC reconfiguration message includes configuration information for the primary cell group (MCG). For example, the UE can apply the RRC configuration message to be configured to communicate with the MCG.

[0092] In at least one example embodiment, the RRC reconfiguration message includes different types of configuration information. For example, the RRC reconfiguration message may include dedicated RRC configurations, such as dedicated bandwidth portion (BWP) configuration information (such as bwp dedicated information element), dedicated random access channel (RACH) configuration information (such as RACH-ConfigDedicated), and / or similar information. In another example, the RRC reconfiguration message may include public RRC configurations, such as public BWP configuration information (such as bwp-public information element), public RACH configuration information (such as RACH-ConfigCommon), public service cell configuration information (such as ServingCellConfigCommon), and / or similar information.

[0093] In some cases, the RRC reconfiguration message includes security configuration information. In at least one example embodiment, the RRC reconfiguration message includes a master key update field. In at least one example embodiment, the master key update field includes information related to a change in the master security key. For example, the master key update field may include a change indicator for the key set, a skip link indicator, and / or similar information.

[0094] In some cases, the RRC reconfiguration message includes bearer configuration information. In at least one example embodiment, the RRC reconfiguration message includes data radio bearer (DRB) configuration information. In at least one example embodiment, the DRB configuration information is included in a radio bearer configuration field, which is embedded within the RRC reconfiguration message.

[0095] In some cases, the RRC reconfiguration message includes configuration information related to Dual Active Protocol Stack (DAPS) operation. In at least one example embodiment, the RRC reconfiguration message includes a DAPS configuration field. In at least one example embodiment, the DAPS configuration field is included in a Data Radio Bearer (DRB) configuration embedded within the RRC reconfiguration message. In at least one example embodiment, the DAPS configuration field indicates that the DRB configured by the DRB configuration is a DAPS bearer. In at least one example embodiment, the presence of the DAPS configuration field in the DRB configuration indicates that the associated DRB is a DAPS bearer.

[0096] In some cases, the RRC reconfiguration message includes Radio Link Control (RLC) configuration information. In at least one example embodiment, the RRC reconfiguration message includes RLC bearer configuration. In at least one example embodiment, the RLC bearer configuration is embedded within the RRC reconfiguration message and used to configure the RLC entity. In at least one example embodiment, the RLC bearer configuration includes a Rebuild RLC field. In at least one example embodiment, the Rebuild RLC field is a directive for the UE to rebuild the RLC entity when the RRC connection is restored. In at least one example embodiment, the presence of the Rebuild RLC field in the RLC bearer configuration indicates that the associated RLC entity must be rebuilt when the RRC connection is restored. In at least one example embodiment, the RLC bearer configuration includes a logical channel identity to indicate the logical channel associated with the RLC bearer configured by the RLC bearer configuration.

[0097] In some cases, the RRC reconfiguration message includes Multiple Radio Access Technology Dual Connectivity (MRDC) configuration information. In at least one example embodiment, the RRC reconfiguration message includes an MRDC subcell group configuration field. In at least one example embodiment, the MRDC subcell group configuration field indicates the configuration or release of an MRDC subcell group.

[0098] While the above example illustrates a UE applying an RRC reconfiguration message in response to receiving an RRC reconfiguration message, in some cases, applying a previously received RRC reconfiguration message may also be desirable. For example, it may be desirable to apply a previously received RRC reconfiguration message when a radio link failure is detected. For instance, when receiving an RRC reconfiguration message to configure the MCG, it may be desirable for the RRC reconfiguration message to include an embedded RRC reconfiguration message that can be applied when a radio link failure of the MCG is detected.

[0099] In at least one example embodiment, when a radio link failure is detected, the UE selects a cell for recovery. When selecting a cell, the UE may use configuration information included in an RRC reconfiguration message that configures the MCG of the failed radio link. Therefore, in such a case, it may be desirable for the RRC reconfiguration message to include configuration information to facilitate such recovery.

[0100] In at least one example embodiment, conditional reconfiguration refers to the process by which a UE applies a conditional RRC reconfiguration message to a selected cell for radio link failure recovery. In such an example, the conditional RRC reconfiguration message may be included within an RRC reconfiguration message that configures the MCG of the failed radio link. For example, the conditional RRC reconfiguration message may include configuration information for a specific cell that enables the UE to configure each layer of the protocol stack to communicate with that specific cell without receiving the RRC reconfiguration message after a radio link failure. Thus, conditional RRC reconfiguration allows the UE to recover from a radio link failure without the delay associated with receiving the RRC reconfiguration message after a radio link failure.

[0101] In at least one example embodiment, the received RRC reconfiguration message includes a conditional reconfiguration field that includes conditional reconfiguration. In at least one example embodiment, conditional reconfiguration is an information element used to configure parameters for a conditional reconfiguration operation. In such an example, conditional reconfiguration specifies configuration information for reconfiguring candidate cells, such as selected cells. In at least one example embodiment, conditional reconfiguration includes an RRC reconfiguration field that includes a second RRC reconfiguration message. For ease of discussion, the RRC reconfiguration message included in the conditional reconfiguration (included in the received RRC reconfiguration) is referred to as the second RRC reconfiguration message. The term "second" is used only to distinguish the RRC reconfiguration message included in the conditional reconfiguration from other RRC reconfiguration messages and does not indicate any meaning other than distinction. For example, the term "second" does not indicate a level, priority order, etc.

[0102] In at least one example embodiment, conditional reconfiguration includes an attempt conditional reconfiguration field. In at least one example embodiment, the attempt conditional reconfiguration field is an indicator that conditional reconfiguration can be used to perform conditional reconfiguration after a radio link failure. In at least one example embodiment, the conditional reconfiguration field instructs the UE to attempt to apply a second RRC reconfiguration message after a radio link failure of the MCG. In at least one example embodiment, the presence of the attempt conditional reconfiguration field in conditional reconfiguration instructs the UE to attempt to apply a second RRC reconfiguration message after a radio link failure of the MCG.

[0103] In at least one example embodiment, Lower Layer Triggered Mobility (LTM) refers to the process by which a UE can change a cell by reconfiguring the lower layer while retaining the configuration of the higher layer. For example, when performing an LTM cell handover, the UE can retain at least a portion of its RLC configuration. This takes into account much less latency and much less processing and signaling overhead in the reconfiguration.

[0104] LTM cell handover can be characterized as a process of retaining some configuration information and releasing some configuration information. In at least one example embodiment, performing an LTM cell handover includes releasing multiple private RRC configurations and multiple public RRC configurations. In at least one example embodiment, performing an LTM cell handover includes retaining radio bearer configurations. In at least one example embodiment, performing an LTM cell handover includes retaining the Cell Radio Network Temporary Identifier (C-RNTI) of the MCG. In at least one example embodiment, performing an LTM cell handover includes retaining the security configuration associated with the master key.

[0105] In at least one example embodiment, LTM cell handover includes reserving the Radio Link Control (RLC) bearer configuration. In at least one example embodiment, reserving the RLC bearer configuration includes reserving the logical channel identity of the RLC bearer configured by the RLC bearer configuration. In at least one example embodiment, reserving the RLC bearer configuration includes reserving the state variables of the RLC bearer configured by the RLC bearer configuration. In at least one example embodiment, reserving the RLC bearer configuration includes reserving the associated RLC entity of the RLC bearer configured by the RLC bearer configuration. In at least one example embodiment, reserving the RLC bearer configuration includes reserving the timer of the RLC bearer configured by the RLC bearer configuration. In at least one example embodiment, reserving the RLC bearer configuration includes reserving the buffer of the RLC bearer configured by the RLC bearer configuration. In at least one example embodiment, reserving the RLC bearer configuration includes resetting the transmission count of the RLC bearer configured by the RLC bearer configuration.

[0106] In some cases, it may be desirable to perform an LTM cell handover to recover from a radio link failure. In such cases, it may be desirable for the received RRC reconfiguration to include an LTM configuration that provides configuration information allowing the UE to perform an LTM cell handover when a radio link failure is detected.

[0107] In at least one example embodiment, the received RRC reconfiguration message includes a lower-layer triggered mobility (LTM) configuration field, which includes an LTM configuration. In at least one example embodiment, the LTM configuration is configuration information for performing LTM cell handover. In at least one example embodiment, the LTM configuration includes an RRC reconfiguration field, which includes a third RRC reconfiguration message. In at least one example embodiment, performing LTM cell handover includes applying the third RRC reconfiguration message. For ease of discussion, the RRC reconfiguration message included in the LTM configuration (included in the received RRC reconfiguration) is referred to as the third RRC reconfiguration message. The term "third" is used only to distinguish the RRC reconfiguration message included in the LTM configuration from other RRC reconfiguration messages and does not indicate any meaning other than distinction. For example, the term "third" does not indicate a level, priority order, etc.

[0108] In at least one example embodiment, the LTM configuration includes an Attempt LTM Handover field. In at least one example embodiment, the Attempt LTM Handover field is an indicator that the LTM configuration can be used to perform an LTM cell handover after a radio link failure. In at least one example embodiment, the Attempt LTM Handover field instructs the UE to attempt an LTM cell handover after a radio link failure of the MCG. In at least one example embodiment, the presence of the Attempt LTM Handover field in the LTM configuration instructs the UE to attempt an LTM cell handover after a radio link failure of the MCG.

[0109] As previously discussed, RRC reconfiguration messages can be used for multiple purposes. For example, they can be used to configure the current cell, to configure conditional reconfiguration for recovery from radio link failures, and to configure LTM cell handover for recovery from radio link failures. However, each of these purposes is associated with different constraints. For example, some configurations for a particular purpose might be incompatible, irrelevant, or undesirable. Therefore, in some cases, it may be desirable to impose constraints on the configuration of the RRC reconfiguration message considered for a specific purpose. Such constraints can improve overall system efficiency and prevent undesirable operations from being performed due to unconstrained configurations that are not applicable to the specific purpose of RRC reconfiguration.

[0110] In at least one example embodiment, various fields are excluded from the second RRC reconfiguration message (i.e., the RRC reconfiguration message including the RRC reconfiguration fields in a conditional reconfiguration). In at least one example embodiment, the term "exclude" refers to a specific field that is not available for inclusion. It may be desirable to exclude fields that are not applicable to conditional reselection from the second RRC reconfiguration message.

[0111] In at least one example embodiment, the LTM configuration field is excluded from the second RRC reconfiguration message. In at least one example embodiment, the LTM configuration field is excluded from the second RRC reconfiguration message because the second RRC reconfiguration message is included in the conditional reconfiguration RRC reconfiguration field.

[0112] In at least one example embodiment, various fields are excluded from the third RRC reconfiguration message (i.e., the RRC reconfiguration message that includes the RRC reconfiguration fields in the LTM configuration). It may be desirable to exclude fields that are not applicable to LTM cell handover from the third RRC reconfiguration message.

[0113] In at least one example embodiment, the conditional reconfiguration field is excluded from the third RRC reconfiguration message. In at least one example embodiment, the conditional reconfiguration field is excluded from the third RRC reconfiguration message because the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration. In at least one example embodiment, the LTM configuration field is excluded from the third RRC reconfiguration message. In at least one example embodiment, the master key update field is excluded from the third RRC reconfiguration message because the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration. In at least one example embodiment, the DAPS configuration field is excluded from the third RRC reconfiguration message. In at least one example embodiment, the DAPS configuration field is excluded from the third RRC reconfiguration message because the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration. In at least one example embodiment, the Rebuild RLC field is excluded from the third RRC reconfiguration message. In at least one example embodiment, the Rebuild RLC field is excluded from the third RRC reconfiguration message because the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration.

[0114] In some cases, it may be desirable to ensure that the third RRC reconfiguration message does not include the MRDC subcell group configuration field indicating any configuration of the MRDC subcell group. However, in such cases, it may be desirable to allow the third RRC reconfiguration message to include the MRDC subcell group configuration field indicating a released value. In at least one example embodiment, the third RRC reconfiguration message includes the MRDC subcell group configuration field indicating a released value. In at least one example embodiment, the MRDC subcell group configuration field indicating the configuration of the MRDC subcell group is excluded from the third RRC reconfiguration message. In at least one example embodiment, since the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration, the MRDC subcell group configuration field indicating the configuration of the MRDC subcell group is excluded from the third RRC reconfiguration message.

[0115] Figure 5 This is a flowchart illustrating activities associated with transition to a selected cell according to at least one example embodiment. In at least one example embodiment, there is... Figure 5 A set of activities, and at least some corresponding operations within those activities. For example, there may exist with... Figure 5 A set of operations associated with the activities of one or more devices. A device, for example... Figure 1 Electronic device 100 or a part thereof, Figure 2 UE 201 or a part thereof, or Figure 2 UE 204 or a portion thereof may utilize the set of operations. The apparatus may include components for performing such operations, such as including... Figure 1 The processor 110. In an example embodiment, by means of, for example, having computer code Figure 1 Memory such as memory 140 is used to transform the device, for example Figure 1 The electronic device 100, the computer code being configured to work with a processor, for example Figure 1 The processor 110 works together to enable the device to perform Figure 5 A set of operations.

[0116] At block 501, the device receives a first Radio Resource Control (RRC) reconfiguration message. In at least one example embodiment, the first RRC reconfiguration message configures the primary cell group (MCG).

[0117] At block 502, the device detects a radio link failure in the MCG. In at least one example embodiment, the MCG is an MCG configured by a first RRC reconfiguration message.

[0118] At block 503, the device determines the selected cell based on a radio link failure of the MCG. In at least one example embodiment, the device determines the selected cell in response to a radio link failure of the MCG.

[0119] At box 504, the device performs a conditional reconfiguration or LTM cell handover on the selected cell based on the first RRC reconfiguration message.

[0120] In at least one example embodiment, the apparatus performs an LTM cell handover to a selected cell based on the LTM configuration included in the first RRC reconfiguration message. In at least one example embodiment, if the LTM configuration includes an "Attempt LTM Handover" field, the apparatus performs an LTM cell handover to the selected cell based on the LTM configuration. In at least one example embodiment, the apparatus determines that the LTM configuration includes an "Attempt LTM Handover" field. In such an example, the apparatus performs an LTM cell handover based on the determination that the LTM configuration includes the "Attempt LTM Handover" field. In at least one example embodiment, the apparatus determines that the selected cell is associated with the LTM configuration, and performs the LTM cell handover based on the determination that the selected cell is associated with the LTM configuration. In at least one example embodiment, determining that the selected cell is associated with the LTM configuration includes determining that the selected cell is an LTM candidate cell corresponding to an LTM candidate field included in the LTM configuration.

[0121] In at least one example embodiment, the apparatus performs a conditional reconfiguration on a selected cell based on a conditional reconfiguration included in a first RRC reconfiguration message. In at least one example embodiment, performing the conditional reconfiguration includes applying a second RRC reconfiguration message, which is included in the conditional reconfiguration included in the first RRC reconfiguration message. In at least one example embodiment, where the conditional reconfiguration includes an attempt at conditional reconfiguration field, the apparatus applies the second RRC reconfiguration message to the selected cell based on the conditional reconfiguration. In at least one example embodiment, the apparatus determines that the selected cell is associated with conditional reconfiguration, and applies the second RRC reconfiguration message to the selected cell based on this determination that the selected cell is associated with conditional reconfiguration.

[0122] Figure 6 This is a flowchart illustrating activities associated with transition to a selected cell according to at least one example embodiment. In at least one example embodiment, there is... Figure 6 A set of activities, and at least some corresponding operations within those activities. For example, there may exist with... Figure 6 A set of operations associated with the activities of one or more devices. A device, for example... Figure 1 Electronic device 100 or a part thereof, Figure 2 UE 201 or a part thereof, or Figure 2 UE 204 or a portion thereof may utilize the set of operations. The apparatus may include components for performing such operations, such as including... Figure 1 The processor 110. In an example embodiment, by means of, for example, having computer code Figure 1 Memory such as memory 140 is used to transform the device, for example Figure 1The electronic device 100, the computer code being configured to work with a processor, for example Figure 1 The processor 110 works together to enable the device to perform Figure 6 A set of operations.

[0123] At block 601, the device receives a first RRC reconfiguration message including LTM configuration. In at least one example embodiment, the first RRC reconfiguration message configures the primary cell group (MCG).

[0124] At block 602, the device detects a radio link failure in the MCG. In at least one example embodiment, the MCG is an MCG configured by a first RRC reconfiguration message.

[0125] At block 603, the device determines the selected cell based on a radio link failure of the MCG. In at least one example embodiment, the device determines the selected cell in response to a radio link failure of the MCG.

[0126] At block 604, the apparatus performs an LTM cell handover to the selected cell based on the LTM configuration. In at least one example embodiment, if the LTM configuration includes an "Attempt LTM Handover" field, the apparatus performs an LTM cell handover to the selected cell based on the LTM configuration. In at least one example embodiment, the apparatus determines that the LTM configuration includes an "Attempt LTM Handover" field. In such an example, the apparatus performs the LTM cell handover based on the determination that the LTM configuration includes the "Attempt LTM Handover" field. In at least one example embodiment, the apparatus determines that the selected cell is associated with the LTM configuration, and the LTM cell handover is performed based on the determination that the selected cell is associated with the LTM configuration. In at least one example embodiment, determining that the selected cell is associated with the LTM configuration includes determining that the selected cell is an LTM candidate cell corresponding to an LTM candidate field included in the LTM configuration.

[0127] Figure 7 This is a flowchart illustrating activities associated with transition to a selected cell according to at least one example embodiment. In at least one example embodiment, there is... Figure 7 A set of activities, and at least some corresponding operations within those activities. For example, there may exist with... Figure 7 A set of operations associated with the activities of one or more devices. A device, for example... Figure 1 Electronic device 100 or a part thereof, Figure 2 UE 201 or a part thereof, or Figure 2 UE 204 or a portion thereof may utilize the set of operations. The apparatus may include components for performing such operations, such as including... Figure 1 The processor 110. In an example embodiment, by means of, for example, having computer code Figure 1 Memory such as memory 140 is used to transform the device, for example Figure 1 The electronic device 100, the computer code being configured to work with a processor, for example Figure 1 The processor 110 works together to enable the device to perform Figure 7 A set of operations.

[0128] At block 701, the device receives a first RRC reconfiguration message including a conditional reconfiguration, which includes a second RRC reconfiguration message. In at least one example embodiment, the first RRC reconfiguration message configures the primary cell group (MCG).

[0129] At block 702, the device detects a radio link failure in the MCG. In at least one example embodiment, the MCG is an MCG configured by a first RRC reconfiguration message.

[0130] At block 703, the device determines the selected cell based on a radio link failure of the MCG. In at least one example embodiment, the device determines the selected cell in response to a radio link failure of the MCG.

[0131] At block 704, the device applies a second RRC reconfiguration message to the selected cell. In at least one example embodiment, where conditional reconfiguration includes an attempt at conditional reconfiguration field, the device applies the second RRC reconfiguration message to the selected cell based on the conditional reconfiguration. In at least one example embodiment, the device determines that the selected cell is associated with conditional reconfiguration, and the application of the second RRC reconfiguration message to the selected cell is based on the determination that the selected cell is associated with conditional reconfiguration.

[0132] Figure 8 This is a flowchart illustrating activities associated with transition to a selected cell according to at least one example embodiment. In at least one example embodiment, there is... Figure 8 A set of activities, and at least some corresponding operations within those activities. For example, there may exist with... Figure 8 A set of operations associated with the activities of one or more devices. A device, for example... Figure 1 Electronic device 100 or a part thereof, Figure 2 UE 201 or a part thereof, or Figure 2 UE 204 or a portion thereof may utilize the set of operations. The apparatus may include components for performing such operations, such as including... Figure 1 The processor 110. In an example embodiment, by means of, for example, having computer code Figure 1 Memory such as memory 140 is used to transform the device, for example Figure 1The electronic device 100, the computer code being configured to work with a processor, for example Figure 1 The processor 110 works together to enable the device to perform Figure 8 A set of operations.

[0133] In some cases, the first RRC reconfiguration message may include both an attempted LTM cell handover field and a conditional reconfiguration field. In such cases, it may be desirable for the UE to determine whether to perform an LTM cell handover or a conditional reconfiguration, since the first RRC reconfiguration enables both options. In at least one example embodiment, the UE prioritizes LTM cell handover over conditional reconfiguration. In such cases, it may be desirable to reduce time and signaling overhead by performing an LTM cell handover.

[0134] However, in some cases, it might be desirable to consider other factors. For example, it might be desirable to determine whether a security update is expected or required. In such cases, it might be desirable for the UE to perform a conditional reconfiguration, which could include a security update, rather than performing an LTM cell handover, which might not be possible.

[0135] At block 801, the device receives a first RRC reconfiguration message including LTM configuration and a conditional reconfiguration including a second RRC reconfiguration message. In at least one example embodiment, the first RRC reconfiguration message configures the primary cell group (MCG).

[0136] At block 802, the device detects a radio link failure of the MCG. In at least one example embodiment, the MCG is an MCG configured by a first RRC reconfiguration message.

[0137] At block 803, the device determines the selected cell based on a radio link failure of the MCG. In at least one example embodiment, the device determines the selected cell in response to a radio link failure of the MCG.

[0138] At box 804, the device determines whether the LTM configuration includes the "Attempt LTM Switching" field and whether the conditional reconfiguration includes the "Attempt Conditional Reconfiguration" field. If both the LTM configuration and the conditional reconfiguration include the "Attempt Conditional Reconfiguration" field, the process proceeds to box 805. If the LTM configuration does not include the "Attempt LTM Switching" field and / or the conditional reconfiguration does not include the "Attempt Conditional Reconfiguration" field, the process proceeds to box 808.

[0139] At box 805, the device determines whether a security update is required. If the device determines that a security update is not required, the process proceeds to box 806. If the device determines that a security update is required, the process proceeds to box 807.

[0140] At box 806, the device performs an LTM cell handover to the selected cell based on the LTM configuration.

[0141] At box 807, the device applies the second RRC reconfiguration message to the selected cell.

[0142] At box 808, the device determines whether the LTM configuration includes an "Attempt LTM Switching" field. If the LTM configuration includes the "Attempt LTM Switching" field, the process proceeds to box 812. If the LTM configuration does not include the "Attempt LTM Switching" field, the process proceeds to box 809.

[0143] At box 809, the device determines whether conditional reconfiguration includes the attempt to conditionally reconfigure field. If conditional reconfiguration includes the attempt to conditionally reconfigure field, the process proceeds to box 811. If conditional reconfiguration does not include the attempt to conditionally reconfigure field, the process proceeds to box 810.

[0144] At box 810, the device performs other actions related to the selected cell.

[0145] At box 811, the device applies the second RRC reconfiguration message to the selected cell.

[0146] At box 812, the device performs an LTM cell handover to the selected cell based on the LTM configuration.

[0147] Embodiments of the present invention can be implemented using software, hardware, application logic, or a combination of software, hardware, and application logic. The software, application logic, and / or hardware may reside on a device, a single device, or multiple separate devices. If desired, some of the software, application logic, and / or hardware may reside on a device, some of the software, application logic, and / or hardware may reside on a single device, and some of the software, application logic, and / or hardware may reside on multiple separate devices. In exemplary embodiments, the application logic, software, or instruction set is maintained on any of a variety of conventional computer-readable media.

[0148] If desired, the different functions discussed herein may be performed in different orders and / or simultaneously with each other. Furthermore, if desired, one or more of the aforementioned functions may be optional or may be combined.

[0149] Although various aspects of the invention are set forth in the independent claims, other aspects of the invention include other combinations of features from the described embodiments and / or dependent claims with features of the independent claims, and not only combinations expressly set forth in the claims.

[0150] It should also be noted that while exemplary embodiments of the invention have been described above, these descriptions should not be construed as limiting. Rather, variations and modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A method performed by a user equipment (UE), the method comprising: Receive a first Radio Resource Control (RRC) reconfiguration message, the first RRC reconfiguration message including: Conditional reconfiguration fields, including conditional reconfiguration, and Lower-level triggered mobility (LTM) configuration fields, including LTM configuration, Conditional reconfiguration includes the RRC reconfiguration field, which in turn includes the second RRC reconfiguration message. The second RRC reconfiguration message includes a master key update field and a data radio bearer (DRB) configuration. The DRB configuration includes a dual active protocol stack (DAPS) configuration field, which indicates that the DRB configured by the DRB configuration is a DAPS bearer. Specifically, the LTM configuration field is excluded from the second RRC reconfiguration message. LTM configuration includes an attempt to switch LTM and an RRC reconfiguration field for LTM configuration. The RRC reconfiguration field for LTM configuration includes a third RRC reconfiguration message, in which: Exclude the conditional reconfiguration field, LTM configuration field, and master key update field from the third RRC reconfiguration message, and Since the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration, the DAPS configuration field is excluded from the third RRC reconfiguration message; Detect radio link failures in the primary cell group (MCG); Selecting a cell based on radio link faults in the MCG; and Based on the LTM configuration, perform an LTM cell handover to the selected cell.

2. The method according to claim 1, wherein, Conditional reconfiguration includes the Attempt Conditional Reconfiguration field, which instructs the UE to attempt to apply a second RRC reconfiguration message after a radio link failure in the MCG.

3. The method of claim 2, further comprising determining that a security update is not required, wherein, The execution of LTM cell handover is based on the determination that no security update is required.

4. The method of claim 1, further comprising determining that the LTM configuration includes an attempt to LTM handover field, wherein the execution of the LTM cell handover is based on the determination that the LTM configuration includes the attempt to LTM handover field.

5. The method according to claim 1, wherein, Because the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration, the conditional reconfiguration field and the LTM configuration field are excluded from the third RRC reconfiguration message.

6. The method according to claim 1, wherein, Because the second RRC reconfiguration message is included in the conditional reconfiguration RRC reconfiguration field, the LTM configuration field is excluded from the second RRC reconfiguration message.

7. A user equipment (UE), comprising At least one processor; and At least one memory, the memory including machine-readable instructions, which, when executed, cause the UE to: Receive a first Radio Resource Control (RRC) reconfiguration message, the first RRC reconfiguration message including: Conditional reconfiguration fields, including conditional reconfiguration, and Lower-level triggered mobility (LTM) configuration fields, including LTM configuration, Conditional reconfiguration includes the RRC reconfiguration field, which in turn includes the second RRC reconfiguration message. The second RRC reconfiguration message includes a master key update field and a data radio bearer (DRB) configuration. The DRB configuration includes a dual active protocol stack (DAPS) configuration field, which indicates that the DRB configured by the DRB configuration is a DAPS bearer. Specifically, the LTM configuration field is excluded from the second RRC reconfiguration message. LTM configuration includes an attempt to switch LTM and an RRC reconfiguration field for LTM configuration. The RRC reconfiguration field for LTM configuration includes a third RRC reconfiguration message, in which: Exclude the conditional reconfiguration field, LTM configuration field, and master key update field from the third RRC reconfiguration message, and Since the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration, the DAPS configuration field is excluded from the third RRC reconfiguration message; Detect radio link failures in the primary cell group (MCG); Selecting a cell based on radio link faults in the MCG; and Based on the LTM configuration, perform an LTM cell handover to the selected cell.

8. The UE according to claim 7, wherein, Conditional reconfiguration includes the Attempt Conditional Reconfiguration field, which instructs the UE to attempt to apply a second RRC reconfiguration message after a radio link failure in the MCG.

9. The UE according to claim 8, wherein, The memory further includes machine-readable instructions that, when executed, cause the UE to determine that a security update is not required, wherein the execution of LTM cell handover is based on the determination that a security update is not required.

10. The UE according to claim 7, wherein, The memory further includes machine-readable instructions that, when executed, cause the UE to determine that the LTM configuration includes an attempt to LTM handover field, wherein the execution of the LTM cell handover is based on the determination that the LTM configuration includes the attempt to LTM handover field.

11. The UE according to claim 7, wherein, Because the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration, the conditional reconfiguration field and the LTM configuration field are excluded from the third RRC reconfiguration message.

12. The UE according to claim 7, wherein, Because the second RRC reconfiguration message is included in the conditional reconfiguration RRC reconfiguration field, the LTM configuration field is excluded from the second RRC reconfiguration message.

13. At least one non-transitory computer-readable medium, comprising instructions that, when executed, perform: Receive a first Radio Resource Control (RRC) reconfiguration message, the first RRC reconfiguration message including: Conditional reconfiguration fields, including conditional reconfiguration, and Lower-level triggered mobility (LTM) configuration fields, including LTM configuration, Conditional reconfiguration includes the RRC reconfiguration field, which in turn includes the second RRC reconfiguration message. The second RRC reconfiguration message includes a master key update field and a data radio bearer (DRB) configuration. The DRB configuration includes a dual active protocol stack (DAPS) configuration field, which indicates that the DRB configured by the DRB configuration is a DAPS bearer. Specifically, the LTM configuration field is excluded from the second RRC reconfiguration message. LTM configuration includes an attempt to switch LTM fields and an RRC reconfiguration fields for LTM configuration that include a third RRC reconfiguration message. Exclude the conditional reconfiguration field, LTM configuration field, and master key update field from the third RRC reconfiguration message, and Since the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration, the DAPS configuration field is excluded from the third RRC reconfiguration message; Detect radio link failures in the primary cell group (MCG); Selecting a cell based on radio link faults in the MCG; and Based on the LTM configuration, perform an LTM cell handover to the selected cell.

14. The medium according to claim 13, wherein, Conditional reconfiguration includes the Attempt Conditional Reconfiguration field, which instructs the User Equipment (UE) to attempt to apply a second RRC reconfiguration message after a radio link failure in the MCG.

15. The medium of claim 14, further comprising determining that no security update is required, wherein the execution of LTM cell handover is based on the determination that no security update is required.

16. The medium of claim 13, further comprising determining that the LTM configuration includes an attempt to LTM handover field, wherein the execution of the LTM cell handover is based on the determination that the LTM configuration includes the attempt to LTM handover field.

17. The medium according to claim 13, wherein, Because the third RRC reconfiguration message is included in the RRC reconfiguration field of the LTM configuration, the conditional reconfiguration field and the LTM configuration field are excluded from the third RRC reconfiguration message.

18. The medium according to claim 13, wherein, Because the second RRC reconfiguration message is included in the conditional reconfiguration RRC reconfiguration field, the LTM configuration field is excluded from the second RRC reconfiguration message.

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