Beam index for Layer 1 / Layer 2 trigger mobility (LTM)

Abstract

Apparatus and methods for beam indices for Layer 1 / Layer 2 trigger mobility (LTM) are disclosed. Advantages of the apparatus / method include reduced cell switching latency. In one embodiment, a user apparatus (UE) receives a medium access control element (MAC-CE) from a serving cell, which includes an index for a candidate cell and the activation of one or more transmit configuration indicator (TCI) states for the candidate cell. The UE further receives a cell switching command from the serving cell via lower-layer signaling, indicating the candidate cell as the target cell. In response to the cell switching command, the UE further switches communication with the serving cell to communication with the target cell, which includes communicating with the target cell by applying at least one of one or more TCI states.

Description

Technical Field

[0001] Various exemplary embodiments generally relate to wireless networking, and more particularly, to beam indicators for layer 1 / layer 2 triggered mobility (LTM) in wireless networking.

Background Art

[0002] Wireless networking provides significant advantages for user mobility. The ability for a user to remain connected while moving provides benefits not only to the user but also higher efficiency and productivity for society as a whole. As user expectations for connection reliability, data speed, and device battery life become more stringent, the technology for wireless networking must also meet such expectations. Thus, there remains an interest in improving wireless networking technology.

Summary of the Invention

[0003] According to aspects of the present disclosure, a user equipment device includes at least one processor and at least one memory. The at least one memory storing instructions, when the instructions are executed by the at least one processor, causes the user equipment device to perform at least: receiving a medium access control control element (MAC-CE) including activation of an indicator of a candidate cell and one or more transmission configuration indicator (TCI) states for the candidate cell from a serving cell; receiving a cell switch command indicating a candidate cell as a target cell from the serving cell via lower layer signaling; and in response to the cell switch command, switching communication with the serving cell to communication with the target cell, wherein communication with the target cell includes communicating with the target cell by applying at least one of the one or more TCI states.

[0004] In some aspects of this disclosure, MAC-CE may include a first field and a second field indicating whether the information in the first field is for a serving cell or for a candidate cell.

[0005] In some aspects of this disclosure, MAC-CE may include a first value and a second value indicating that the first value identifies a candidate cell.

[0006] In some aspects of this disclosure, MAC-CE may include a candidate cell-specific TCI state list containing one or more TCI states.

[0007] In some aspects of this disclosure, a cell switching command may further include a reference to at least one of one or more TCI states.

[0008] In one aspect of the present disclosure, an instruction may, when executed by at least one processor, cause a user device to perform at least the step of receiving a cell switching command by receiving downlink control information (DCI) which includes at least an index of a candidate cell and a TCI code point that refers to at least one of one or more TCI states.

[0009] In one aspect of the present disclosure, an instruction may, when executed by at least one processor, cause a user device to perform the step of receiving a cell switching command by receiving downlink control information (DCI) which includes at least an index of a candidate cell activation TCI list containing a candidate cell and a TCI code point that refers to at least one of one or more TCI states.

[0010] In one aspect of the present disclosure, an instruction may, when executed by at least one processor, cause a user device to further perform the step of receiving a cell switching command by receiving downlink control information (DCI) which includes at least a reference to at least one of one or more TCI states and an indicator that at least one of one or more TCI states is for a candidate cell.

[0011] In one aspect of the present disclosure, the instruction may, when executed by at least one processor, cause a user equipment to perform at least intra-cell beam management in a target cell based on one or more TCI states.

[0012] In one aspect of the present disclosure, one or more TCI states are associated with a plurality of physical cell identifiers (PCIs), and the instruction, when executed by at least one processor, can cause a user equipment to further perform the step of performing at least one of intra-cell beam management or inter-cell beam management in a target cell based on one or more TCI states.

[0013] In one aspect of the present disclosure, an instruction, once executed by at least one processor, may cause a user device to further perform the step of maintaining a TCI state list activated by the serving cell, at least while operating in the target cell.

[0014] In one aspect of the present disclosure, when an instruction is executed by at least one processor, the instruction includes at least the step of transmitting an indicator of user device capability, wherein at least one of one or more TCI states activated in the MAC-CE for a candidate cell or a number of TCI states activated across multiple cells in the user device may cause the user device to perform further steps based on user device capability.

[0015] A part of the present disclosure provides a method performed by a user device. The method includes: receiving a media access control control element (MAC-CE) from a serving cell, which includes an index of a candidate cell and the activation of one or more transmit configuration indicator (TCI) states for the candidate cell; receiving a cell switching command from the serving cell via lower layer signaling, which indicates the candidate cell as a target cell; and in response to the cell switching command, switching communication with the serving cell to communication with a target cell, the communication with the target cell comprising communicating with the target cell by applying at least one of one or more TCI states.

[0016] In some aspects of this disclosure, the MAC-CE may include a first field and a second field indicating whether the information in the first field is for a serving cell or for a candidate cell.

[0017] In some aspects of this disclosure, MAC-CE may include a first value and a second value indicating that the first value identifies a candidate cell.

[0018] In some aspects of this disclosure, MAC-CE may include a candidate cell-specific TCI state list containing one or more TCI states.

[0019] In some aspects of this disclosure, a cell switching command may further include a reference to at least one of one or more TCI states.

[0020] In one aspect of the present disclosure, the step of receiving a cell switching command may include the step of receiving downlink control information (DCI) which includes an index of a candidate cell and a TCI code point that refers to at least one of one or more TCI states.

[0021] In one aspect of the present disclosure, the step of receiving a cell switching command may include receiving downlink control information (DCI) which includes an index of a candidate cell activation TCI state list that includes a candidate cell and a TCI code point that refers to at least one of one or more TCI states.

[0022] In some aspects of the present disclosure, the step of receiving a cell switching command may include the step of receiving downlink control information (DCI) which includes a reference to at least one of one or more TCI states and an indicator that at least one of the one or more TCI states is for a candidate cell.

[0023] In some aspects of the present disclosure, the method may further include the step of associating one or more TCI states with a plurality of physical cell identifiers (PCIs), and performing intra-cell beam management in a target cell based on one or more TCI states.

[0024] In some aspects of this disclosure, one or more TCI states are associated with a plurality of physical cell identifiers (PCIs), and the method may further include the step of performing at least one of intra-cell management or inter-cell management in a target cell based on one or more TCI states.

[0025] In some aspects of the present disclosure, the method may further include the step of maintaining a list of TCI states activated by the serving cell while operating in the target cell.

[0026] In some aspects of the present disclosure, the method may further include a step of transmitting an indicator of user equipment capability, wherein at least one of the following steps is based on UE capability: the number of one or more TCI states activated in the MAC-CE for a candidate cell, or the number of TCI states activated across multiple cells in the user equipment device.

[0027] According to an aspect of the present disclosure, a network device includes at least one processor and at least one memory. The at least one memory stores instructions which, when executed by the at least one processor, cause the network device to perform at least the steps of transmitting, to a user equipment device, a medium access control control element (MAC-CE) including an indicator of a candidate cell and activation of one or more transmission configuration indicator (TCI) states for the candidate cell; transmitting, to the user equipment device via lower layer signaling, a cell switching command indicating the candidate cell as a target cell; and performing, in response to the cell switching command, a handover of the user equipment device to the target cell.

[0028] According to an aspect of the present disclosure, a method performed by a network device is provided. The method includes transmitting, to a user equipment device, a medium access control control element (MAC-CE) including an indicator of a candidate cell and activation of one or more transmission configuration indicator (TCI) states for the candidate cell; transmitting, to the user equipment device via lower layer signaling, a cell switching command indicating the candidate cell as a target cell; and performing, in response to the cell switching command, a handover of the user equipment device to the target cell.

[0029] According to some aspects, the subject matter of the independent claims is provided. Some further aspects are defined in the dependent claims.

[0030] Exemplary embodiments of the present invention will be described below with reference to the drawings.

Brief Description of the Drawings

[0031] [Figure 1] FIG. 1 is a diagram of an exemplary embodiment of wireless networking between a network device and a user equipment device (UE) according to one exemplary aspect of the present disclosure. [Figure 2]Figure 2 is a diagram of an exemplary embodiment of a UE sweeping a received beam for a synchronous signal block (SSB) burst according to one exemplary aspect of the present disclosure. [Figure 3] Figure 3 shows an exemplary embodiment of a UE communicating with a master node (MN) and a secondary node (SN) according to one exemplary aspect of the present disclosure. [Figure 4] Figure 4 illustrates an exemplary embodiment of a Layer 1 / Layer 2 trigger mobility (LTM) scenario according to one exemplary aspect of the present disclosure. [Figure 5] Figure 5 is a diagram illustrating an exemplary embodiment of operation for LTM according to one exemplary aspect of the present disclosure. [Figure 6] Figure 6 is a diagram of an exemplary configuration for provisioning an LTM according to one exemplary aspect of the present disclosure. [Figure 7] Figure 7 shows an exemplary Transmit Configuration Indicator (TCI) State Activated Medium Access Control Control Element (MAC-CE) for a candidate cell to support LTM according to one exemplary embodiment of the present disclosure. [Figure 8] Figure 8 is a flowchart illustrating exemplary operation of a UE for LTM according to one exemplary embodiment of the present disclosure. [Figure 9] Figure 9 is a flowchart illustrating exemplary operation of a network device for LTM according to one exemplary embodiment of the present disclosure. [Figure 10] Figure 10 shows an exemplary embodiment of a component of a UE or network device according to one exemplary aspect of the present disclosure. [Modes for carrying out the invention]

[0032] The following description includes several specific details in order to provide a complete understanding of the disclosed embodiments. However, those skilled in the art will recognize that embodiments can be carried out without one or more of these specific details, or using other methods, components, materials, etc. In other examples, well-known structures relating to transmitters, receivers, or transceivers are not shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0033] Throughout this specification, any reference to “one aspect” or “a certain aspect” means that a particular feature, structure, or characteristic described in relation to an aspect is included in at least one aspect. Therefore, occurrences of the phrase “in one aspect” or “a certain aspect” in various places throughout this specification do not necessarily all refer to the same aspect. Furthermore, a particular feature, structure, or characteristic can be combined in any suitable way in one or more aspects.

[0034] The embodiments described herein, without limitation, may be implemented in wireless networking equipment, particularly in devices utilizing Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM®, 2G), GSM® EDGE Radio Access Network (GERAN), General-Purpose Packet Radio Services (GRPS), Universal Mobile Telecommunications System (UMTS, 3G) based on Basic Broadband Code Division Multiple Access (W-CDMA), High-Speed ​​Packet Access (HSPA), Long-Term Evolution (LTE), LTE Advanced, Enhanced LTE (eLTE), 5G New Radio (5G NR), 5G Advanced, 6G (and beyond), and 802.11ax (Wi-Fi 6). Here, the term "eLTE" means LTE Evolution connected to a 5G core. LTE is also known as Evolved UMTS Terrestrial Radio Access (EUTRA) or Evolved UMTS Terrestrial Radio Access Network (EUTRAN).

[0035] In recent years, wireless networking technology has benefited from beamforming. Beamforming is a technique in which an array of antennas can be guided to transmit or receive radio signals in a specific spatial direction. Beamforming may involve adjusting the phase of the signal transmitted or received from an antenna element so that the transmitted or received signal can provide constructive interference in a desired spatial direction and destructive interference in other spatial directions. For example, in a wireless network, a base station and a user equipment (UE) may each have one or more antenna panels or antenna arrays. This antenna panel or antenna array has antenna elements that can be configured to focus transmitted signal energy in a specific spatial direction and / or within a specific spatial angular sector or width, and / or receive signal energy in a specific spatial direction and / or within a specific spatial angular sector or width. A base station can transmit various reference signals in various different beam directions to facilitate UE access to and communication with the network. The base station may configure the UE to perform signal measurements (e.g., Layer 1 reference signal received power (L1 RSRP)) and report those signal measurements, so that the base station and UE can select the beam direction with the strongest signal intensity for communication. In one example, the base station may transmit synchronous signal blocks (SSBs) in bursts. The base station can transmit SSB bursts in various beam directions, for example, by sweeping across a set of beam directions. To facilitate in-frequency and inter-frequency beam management, the base station can provide the UE with information such as physical cell identification (PCI) or logical ID, time-domain information (e.g., SSB measurement configuration (SMTC) or periodicity and SSB time position in bursts).To facilitate inter-frequency beam management, the base station may provide the UE with frequency-domain information such as the SSB center frequency and / or SSB subcarrier spacing (SCS). Generally, the base station may transmit any suitable reference signal (e.g., a predetermined waveform or sequence) and provide the UE with any suitable parameters and / or configurations to facilitate signal measurement, measurement reporting, beam indexing, and beam selection.

[0036] In the example of fifth-generation new radio (5G NR) as defined by the Third Generation Partnership Project (3GPP), an integrated TCI framework is used for beam configuration and / or indices. For example, a base station may configure a UE using a set of TCI states. Each TCI state may indicate at least a specific beam direction or group of beam directions that can correspond to a particular reference signal. In one example, a TCI state may be a downlink (DL) TCI state for DL ​​communication from the base station to the UE. In another example, a TCI state may be an uplink (UL) TCI state for UL communication from the UE to the base station. In yet another example, a TCI state may be a joint TCI state for UL and DL communication between the base station and the UE. A base station may activate a UE using at least a subset of the configured TCI states. In some examples, a base station may activate one or more configured TCI states in the set and exclude one or more other configured TCI states in the set. To communicate with the UE, the base station may select one of the activated TCI states and present the selected TCI state to the UE.

[0037] Since UEs can move from one area to another, handover or mobility procedures can be crucial to support the UE's continuous communication with the network (without any interruption, or at least minimal interruption). For example, a UE could be configured to monitor several reference signals from one or more base stations (e.g., SSB, Channel Status Information Reference Signal (CSI-RS), DL Reference Signal (RS)), perform signal measurements of the reference signals, and report those measurements to the network, thereby enabling a decision to hand over the UE to an adjacent base station (if signal quality degradation is detected). The initiation of a handover can typically originate from the network. In the case of 5G NR, the handover initiation or handover command may be signaled via higher-layer signaling, such as Radio Resource Control (RRC) signaling. Higher-layer signaling may involve the network and therefore can have high latency. However, some UEs may be advanced mobile devices and / or located within advanced mobile wireless communication systems. Therefore, a UE may benefit from more efficient handover procedures triggered via lower-layer signaling, such as L1 / L2 signaling, which has lower latency than higher-layer signaling. As used herein, handovers triggered via lower-layer signaling are sometimes referred to as lower-layer triggered mobility (LTM). In some cases, candidate cells for LTM are sometimes referred to as LTM candidate cells.

[0038] Aspects of this disclosure provide techniques for beam indices in LTM procedures by using cell-specific TCI states or lists of cell-specific TCI states. In some aspects of this disclosure, a serving cell (e.g., a base station, a centralized unit (CU) (e.g., a server or host), a distributed unit (DU) (e.g., a radio head), a network node, or generally a serving cell device) may constitute a UE with one or more candidate cells and a list of one or more TCI states for each of the candidate cells. For each individual candidate cell, the serving cell may activate one or more of the configured TCI states. In other words, TCI state activation is cell-specific. The serving cell may then transmit a cell switching command to the UE via lower-layer signals (e.g., L1 / L2 signaling). For example, a cell switching command may be transmitted when a degradation in signal quality between the UE and the base station is detected. The cell switching command may designate one of the candidate cells as the target cell (for handover). In response to a cell switching command, the UE can switch to communicate with a target cell (e.g., a base station, CU, DU, network node, or generally the equipment of the target cell). The UE can communicate with the target cell by applying at least one of one or more activated TCI states. In one embodiment, the activation of a TCI state for a candidate cell may be via medium access control element (MACE-CE) signaling.

[0039] Aspects of this disclosure offer various advantages. For example, (pre)activating TCI states for candidate cells while the UE is in a serving cell allows the UE to begin tracking the RS (of the candidate cell) associated with the TCI state at an earlier time (e.g., before the beam indicator that indicates to the UE that a beam / TCI state should be applied for communication). This thus enables and / or may enable a more efficient cell switching process (e.g., reduced cell switching latency) compared to a case where no (pre)activated TCI states are provided to the UE.

[0040] This disclosure may use the term “serving cell” to refer to a base station, CU, DU, network node, or network equipment of a UE serving cell, and may use the term “target cell” to refer to a base station, CU, DU, network node, or network equipment of a target cell for cell switching. A serving cell may be a PCell (primary cell or SpCell (special cell)) or an SCell (secondary cell).

[0041] Figure 1 illustrates an exemplary embodiment of wireless networking between a network device 110 and a user equipment device (UE) 150. The network device 110 is configured to form beams 120 in multiple directions, and the UE 150 is also configured to form beams 160 in multiple directions. As those skilled in the art will understand, the ability to beamform in multiple directions can be implemented using an arrangement of multiple radiating elements, which may also be called an “array” of radiating elements. Beamforming (also known as spatial filtering) achieves the transmission or reception of directional signals by utilizing individual arrays and / or by combining elements within the array in a manner such as signals at specific angles that may result in constructive or destructive interference. In the following description, this may be referred to as a “broad beam.” Those skilled in the art will understand and recognize a broad beam for any given array. For example, those skilled in the art will understand and recognize a broad beam based on half-power beamwidth. In embodiments, a broad beam may be produced by a single radiating element in an array, or by multiple radiating elements having a specific weight (i.e., a phase shifter setting).

[0042] Examples of wireless networking devices that apply beamforming in multiple directions include, but are not limited to, devices implementing 5G NR and devices implementing Wi-Fi 6. This disclosure describes embodiments related to 5G NR (and generations beyond 5G) and embodiments including those defined by 3GPP. In such embodiments, the network device 110 may be a gNodeB (known as a gNB). However, embodiments relating to other wireless networking technologies are intended to be included within the scope of this disclosure.

[0043] In wireless communication, a node may be implemented at least partially by CUs (e.g., servers or hosts) operably coupled to one or more DUs (e.g., wireless heads). In embodiments, node operation may be distributed among multiple centralized units (e.g., servers or hosts). In embodiments, network nodes in 5G wireless networking may be implemented based on a so-called CU-DU partition. In embodiments, processing tasks may be performed in either the CU or the DU, and the shift of responsibilities between the CU and the DU may be configurable according to a particular implementation.

[0044] Continuing to refer to Figure 1, in the example of a 5G NR network, network device 110 provides a cell that defines the coverage area of ​​network device 110. As described above, network device 110 may be a gNB of a 5G NR network, or any other device configured to control radio communications and manage radio resources within a cell. As used herein, the term “resource” may refer to radio resources such as physical resource blocks (PRBs), radio frames, subframes, time slots, subbands, frequency domains, subcarriers, and beams. In embodiments, network device 110 may be referred to as a base station.

[0045] UE150 may include, but is not limited to, smartphones, tablets, portable computers, in-vehicle wireless terminal devices, Internet of Things (IoT) devices, and / or watches or other wearable devices. Network device 110 may provide UE150 with wireless access to other networks, such as the Internet. Wireless access may include downlink (DL) communication from network device 110 to UE150 and uplink (UL) communication from UE150 to network device 110. As used herein, the terms “transmit” and / or “receive” may mean transmitting and / or receiving wirelessly over a wireless propagation channel on a radio resource, respectively. There may be other UEs in the cell, each of which may be served by the same or different network devices, such as network device 110.

[0046] 3GPP defines 5G NR frequency ranges such as frequency range 2 (FR2), covering 24.25 GHz to 52.6 GHz, which include high frequencies and bands with very high bandwidth capable of accommodating high data rate use cases. Such bands may be subject to challenging propagation conditions, including high path loss, absorption from the environment, and transmission loss, among other conditions. To address such conditions, beam management procedures may be used, such as using highly directional beams in network equipment 110 and UE150.

[0047] Continuing to refer to Figure 1, various examples of beam 120 are shown for the network device 110, and various examples of beam 160 are shown for the UE 150. A consequence of using highly directional beams is that some of the network device beams 120 may not be usable with some of the UE beams 160 due to large differences in directivity. Therefore, the UE 150 "sweeps" its beam 160, and the network device 110 "sweeps" its beam 120 to determine which beam pairing has the highest signal power and is therefore best usable for communication. Beams that are not perfectly directionally aligned may have the highest signal power due to various propagation conditions. The sweeping is described in more detail in relation to Figure 2. After identifying such beam pairings, the UE 150 and the network device 110 can use the identified beams to initiate an access procedure for the UE 150 to access the network device 110.

[0048] Figure 2 is a diagram of an exemplary embodiment of a UE sweeping a receiving beam for an SSB burst. Using the exemplary beam shown in Figure 1, the network device 110 successively forms beams B1, B2, B3, and B4. Each beam formation is called a “burst.” The network device 110 may generate bursts at intervals observed by the UE 150. Each time between intervals is called a “burst period” and may be longer than the duration of the burst. As those skilled in the art will understand, beamforming for transmission is implemented by controlling the phase and relative amplitude of the transmitted signal at each radiating element in the array to produce a desired pattern of constructive and destructive interference at a desired wavefront. In contrast, beamforming for reception is implemented by combining information from different elements of the array so that radiation in a target spatial region is preferentially observed.

[0049] In the 5G NR example, each beam in a burst transmits information about the beam in what is called a signal synchronization block (SSB). Network equipment 110 may be a gNodeB and transmits an SSB on each beam in the burst. In some examples, network equipment 110 may operate using one SSB (single-beam operation) or multiple SSBs (multi-beam operation). In embodiments, UE 150 may receive an SSB burst for each of its receiving beams. In the example of four receiving beams R1, R2, R3, and R4 shown in Figure 1, there are four intervals between burst receptions, as shown in Figure 2. In some examples, UE 150 may operate using a single beam (e.g., an omnidirectional beam). The SSB of an SS burst may be provided by one or more (collocated or uncollocated) transmit-receive points (TRPs). The duration between bursts is called the "burst periodicity". In a 5G NR network, each SSB burst can last 5 ms, and the burst periodicity can have a default duration of 20 ms. None of the embodiments of this specification are limited to a specific downlink reference signal. For example, a downlink beam may be identified by a Channel State Information Reference Signal (CSI-RS) identifier and / or by an SSB (e.g., Synchronization Signal Physical Broadcast Channel (SS / PBCH) block) identifier and / or by any reference signal / sequence transmitted using a beam / spatial filter.

[0050] In the 5G NR example, each SSB contains system information (SI) in the form of a Master Information Block (MIB) and several System Information Blocks (SIBs). The SI is divided into minimal SI and other SIs. The minimal SI contains basic information available to access network nodes and information for obtaining other SIs. The minimal SI includes the MIB, which contains cell prohibition status information and physical layer information of the cell for receiving further system information (e.g., CORESET#0 configuration). The MIB is broadcast periodically on the broadcast channel (BCH). The minimal SI also includes System Information Block 1 (SIB1), which defines the scheduling of other system information blocks and contains information for accessing network nodes. SIB1 is sometimes called the residual minimal SI (RMSI) and is broadcast periodically on the downlink shared channel (DL-SCH).

[0051] More specifically, in an embodiment, the MIB on the public broadcast channel (PBCH) may provide the UE150 with parameters (e.g., a CORESET#0 configuration) for monitoring the public downlink control channel (PDCCH) for scheduling the public downlink shared channel (PDSCH) that carries the SIB1. In an embodiment, the PBCH may indicate that there is no associated SIB1, in which case the UE150 may be directed to other frequencies for searching for an SSB associated with the SIB1, and may be directed to a frequency range in which the UE150 can assume that there is no SSB associated with the SIB1. The indicated frequency range may be limited to the same operator's continuous spectral allocation in which the SSB is detected.

[0052] Continuing to refer to Figure 2, for each transmit-receive beam pair, the UE 150 measures the reference signal received power (RSRP). In the embodiment, the beam pair with the maximum RSRP is selected. In the embodiment, any beam pair with sufficient RSRP may be selected. Once the beam pair is identified, the UE 150 decodes the SSB of the selected network node transmit beam and decodes its contents, such as the MIB and / or SIB1. As described above, the MIB contains cell information for receiving further system information, and the SIB1 contains information for accessing network nodes, defining the scheduling of other system information blocks. Such information may be used by the UE 150 to establish a connection with the network device 110.

[0053] In some examples, the characteristics of each transmit-receive beam pair can be mapped to a TCI state. In one example, a transmit-receive beam pair can be mapped to a DL TCI state for DL ​​communication from the network to the UE and to a UL TCI state for UL communication from the UE to the network. In another example, a transmit-receive beam pair can be mapped to a joint TCI state for UL and DL communication between the network and the UE.

[0054] The examples in Figures 1 and 2 are for illustrative purposes only. In the embodiment, the number and direction of network node beams and the number and direction of UE beams may differ from those shown in Figures 1 and 2.

[0055] In some cases, it may be beneficial for the network to utilize dual connectivity and / or carrier aggregation in addition to beamforming to increase bandwidth and bitrate for communication with the UE. This will be discussed in more detail below, relating to Figure 3.

[0056] Figure 3 shows an exemplary embodiment of UE310 communicating with MN320 and SN330. UE310 may be substantially similar to UE150 in Figure 1. In embodiments, MN320 and / or SN330 may be 5G NR nodes (e.g., gNB) or LTE network nodes (e.g., eNB), among other types of nodes. In embodiments, MN320 and / or SN330 may be base stations. UE310 may operate in dual connectivity mode. Dual connectivity allows UE310 to connect to two network nodes (e.g., MN320 and SN330 shown) simultaneously.

[0057] In embodiments, the MN320 connects to a core network such as a 5G core (5GC) and provides control plane connectivity between the UE310 and the core network, while the SN330 connects to the MN320 (e.g., via an Xn interface) and provides additional resources for user plane traffic. In embodiments, the MN320 handles signaling messages such as RRC signaling messages. In embodiments, using signaling radio bearers (SRBs) for LTE networks (e.g., SRB0, SRB1 and / or SRB2) and / or 5G NR networks (e.g., SRB3), the SN330 can also handle signaling messages such as RRC signaling messages. As those skilled in the art will understand, RRC is used by nodes and UEs for various radio resource operations, including, but not limited to, connectivity management and mobility functions. As used herein, the term “resource” may refer to radio resources such as physical resource blocks (PRBs), radio frames, subframes, time slots, subbands, frequency domains, subcarriers, and beams. As used herein, the terms “transmit” and / or “receive” may refer to wirelessly transmitting and / or receiving over a wireless propagation channel on a radio resource, respectively. Those skilled in the art will understand RRC and SRB.

[0058] As further illustrated in the example in Figure 3, carrier aggregation can be used in conjunction with dual connectivity. Carrier aggregation allows the UE310 to connect to multiple cells simultaneously so that it operates on multiple frequencies at the same time. In embodiments, multiple cells may be located in a single base station and / or a common location (e.g., a small cell or femtocell in a facility). One or more cells that may be available to the UE under carrier aggregation may be referred to as a “cell group”. When carrier aggregation is used in conjunction with dual connectivity, the MN and / or SN may have cell groups. The cell group of the MN may be called the master cell group (MCG), and the cell group of the SN may be called the secondary cell group (SCG). The MCG includes a primary cell (PCell) and may include one or more secondary cells (SCells). The SCG includes a primary cell (PSCell) of the secondary cell group and may include one or more secondary cells (SCells). In the example shown in Figure 3, the MN320 includes one PCell322 and one SCell324. Similarly, SN330 includes one PCell332 and one SCell334. Each of the PCell322, SCell324, PCell332, and SCell334 may be operated by a network device substantially similar to the network device 110 in Figure 1. Those skilled in the art will understand the characteristics and functions of such cells and cell groups.

[0059] In some cases, the MN320 and / or SN330 may utilize beamforming techniques to communicate with the UE310, as described above with reference to Figures 1 and 2.

[0060] As explained above, UEs may move from one area to another, and therefore, handover or mobility procedures may be important to support the continued communication of UEs with the network. Furthermore, more efficient handover processes such as LTM may be beneficial in avoiding or at least reducing any disruption to UE services when UEs move from one cell coverage to another.

[0061] Figure 4 is a diagram of an exemplary embodiment of an LTM scenario. As shown in Figure 4, UE410 can communicate with network equipment 420 (e.g., base station, gNB) as indicated by solid arrows and be serviced by network equipment 420. UE410 may be substantially similar to UE150 in Figure 1 and / or UE310 in Figure 3. Network equipment 420 may be substantially similar to network equipment 110 in Figure 1 and / or PCell322, SCell324, PCell332 and SCell334 in Figure 3. Network equipment 420 that is actively or currently serviced to UE410 may be called a serving cell. When UE410 moves toward the edge of a cell or area 402 that is serviced (or under coverage) by network equipment 420, a handover procedure may be performed to hand over UE410 to an adjacent cell serviced by another network device. In the example shown in Figure 4, one adjacent cell is serviced by network device 430, and another adjacent cell is serviced by network device 440. Network device 440 can cover (or service) a cell or area 406, and network device 430 can cover area 404. In some examples, areas 402, 404, and 406 can partially overlap as shown. In other examples, areas 402, 404, and 406 may not overlap. In the context of handover, adjacent cells may be called candidate cells. In the context of LTM, adjacent cells may be called LTM candidate cells.

[0062] In one embodiment, each of the network devices 420, 430, and 440 and UE410 may perform beamforming as described above with reference to Figure 1. Furthermore, each of the network devices 420, 430, and 440 may transmit RS such as SSB as described above with reference to Figure 2 to facilitate signal measurement and / or reporting by UEs such as UE410. Furthermore, UE410 may be simultaneously served by multiple cells using carrier aggregation and / or dual connectivity, for example, as described above with reference to Figure 3.

[0063] To facilitate LTM, the network device 420 (or serving cell) can configure UE410 for signal measurement (e.g., L1-RSRP) in various ways. In a first example, UE410 may be provided with a configuration for L1 measurement of RS under ServingCellConfig for its serving cell. In some examples, it may be useful to reuse an inter-cell beam management (ICBM) mechanism as defined in 3GPP Release 17. In a second example, UE410 may be provided with a configuration for L1 measurement under CellGroupConfig for candidate cells. In a third example, UE410 may be provided separately under ServingCellConfig for L1 measurement of RS for serving cells and under CellGroupConfig for L1 measurement of RS for candidate cells. Those skilled in the art will understand the characteristics and functions of such ServingCellConfig and CellGroupConfig.

[0064] To further facilitate beam indexing for LTM, the UE410 may provide beam indexes associated with candidate cells before, after, or as part of a cell switching command. Therefore, an LTM framework that incorporates beam indexes needs to be designed.

[0065] According to one aspect of this disclosure, a network device 420 (serving cell) may serve a UE 410 during a certain period of time and may pre-activate the UE 410 with TCI states for candidate cells. Pre-activation may be cell-specific. In this regard, the network device 420 may transmit an index of one or more candidate cells (e.g., network devices 430, 440) and the activation of each of the lists of one or more TCI states for each of the one or more candidate cells. Upon detection of degradation in operation or communication with the UE 410, the serving cell network device 420 may send a cell switching command to the UE 410 via lower-layer signaling (e.g., L1 / L2 signaling). The cell switching command may indicate one of the one or more candidate cells selected as the target cell for cell switching. In response to receiving the cell switching command, the UE 410 may switch to communicate with the target cell by applying at least one of the one or more activated TCI states for each.

[0066] In the example illustrated in Figure 4, UE410 can utilize various beams for communication. To avoid confusion in the diagram of Figure 4, only two beams, 412 and 414, are shown. Beams 412 and 414 may be substantially the same as the beams described above with reference to Figures 1 and 2. Network device 420 (serving cell) can activate a TCI state in UE410 corresponding to beam 412 for a candidate cell operated by network device 430. Network device 420 can further activate a TCI state in UE410 corresponding to beam 414 for a candidate cell operated by network device 440. In the case of LTM, network device 420 can designate a cell operated by network device 430 as the target cell. As part of cell switching, UE410 can switch to communicate with network device 430 (target cell), as indicated by the dashed arrow. UE410 can communicate with the target cell using beam 412 corresponding to the TCI state activated by the serving cell. The mechanism for LTM beam indexing will be discussed in more detail below with reference to Figures 5-7.

[0067] The examples in Figures 3 and 4 are for illustrative purposes only. In the embodiment, the number of PCells and SCells in the MN and / or SN, the number of candidate cells, and the number of activated TCI states (or beams) may differ from those shown in Figures 3 and 4.

[0068] Figures 5 to 7 are described in relation to each other to illustrate a mechanism for LTM beam indices that use TCI states, for example, to extend the integrated TCI framework defined by 3GPP.

[0069] Figure 5 is a diagram illustrating an exemplary embodiment of operation for LTM. The operation is implemented between UE510, serving cell 520, and target cell 530 for LTM. In some examples, each of UE510, serving cell 520, and target cell 530 may implement the operation using a device having components as shown in Figure 11. One or more of the following operations may be implemented in relation to the operations of this disclosure, such as the examples described above with reference to Figures 1 to 4. UE510 may be similar to UE150, 310, and / or 410. Serving cell 520 and target cell 530 may be similar to network devices 110, 420, and / or 430. As shown, Figure 5 includes several enumerated steps, but the modes of operation in Figure 5 may include additional steps before, after, and between the enumerated steps. In some modes, one or more of the enumerated steps may be omitted or performed in a different order.

[0070] In some examples, carrier aggregation may be used between UE510, serving cell 520, and target cell 530 (when the target cell is a SCell). For example, serving cell 520 may be a PCell similar to PCell322 and / or PCell322332, and target cell 530 may be a PCell or SCell similar to SCell324 and / or SCell334. In other words, the LTM operation in Figure 5 may be used to switch UE510 from a serving PCell to a target PCell, or from a serving PCell to a target SCell. However, the cell switch may be initiated or triggered from the serving PCell. In some examples, inter-cell beam management may be used between UE510, serving cell 520, and target cell 530 (the target having a different PCI than the serving cell). In other words, the inter-cell beam management operation in Figure 5 may be used before switching UE510 from a serving PCell to a target cell. In general, the LTM operations described herein may be applicable to cells having a different PCI than the PCell and / or SCell and / or serving cell during a cell switching or handover process.

[0071] As shown in Figure 5, in 502, the serving cell 520 transmits a configuration and the UE 510 receives a configuration. The configuration may be received, for example, during the LTM preparation phase. The configuration may include, for example, the configuration of one or more cells, including the serving cell and / or one or more candidate cells, and a list of one or more TCI states for each of the one or more cells. The configuration can be in various formats, as discussed below with reference to, for example, Figure 6.

[0072] Figure 6 is a diagram of an exemplary configuration 600 for provisioning an LTM. Configuration 600 may be called CellGroupConfig. Generally, configuration 600 may refer to a set of cells configured for LTM operation (this may include one or more serving cells and / or one or more candidate cells). Configuration 600 may include configurations for each of the multiple cells associated with the LTM. In the illustrated example of Figure 6, configuration 600 includes configuration 610, which may be called ServingCellConfig, for a PCell identified by index 0 and LTM index 0. Configuration 600 further includes configuration 620, which may be called ServingCellConfig, for a candidate cell identified by LTM index 1. Configuration 600 further includes configuration 630, which may be called ServingCellConfig, for a candidate cell identified by LTM index 2. Cells may have other index values ​​depending on which of the cells is servicing (and therefore providing configuration) to a UE; for example, an LTM cell (having index 2) may be a PCell of another UE. The LTM indexes referred to herein are examples, and LTM cells may be referred to by cell identifiers, LTM configuration indexes, or any identifier that can be used to refer to a particular cell. A serving cell (e.g., PCell) can also be an LTM cell (which can be referred to by an LTM index, etc.).

[0073] Each of configurations 610, 620, and 630 may include a TCI configuration for its respective cell. For example, as further shown in Figure 6, configuration 610 includes a TCI configuration 614 containing a TCI state list 612 for a PCell (e.g., serving cell 520) currently servicing a UE (e.g., UE510). Configuration 620 is a TCI configuration 624 containing a TCI state list 622 for an LTM candidate identified by LTM index 1. Similarly, configuration 630 includes a TCI configuration 634 containing a TCI state list 632 for an LTM candidate identified by LTM index 2. Each of the TCI state lists 612, 622, and 632 may contain one or more TCI states (e.g., 1, 2, 3, 4, 5, 6, or more). In some embodiments, each cell (e.g., serving cell, candidate cell) may have an independent configuration of TCI states or TCI state lists. Therefore, a TCI state with a certain value (e.g., 1) for one cell may refer to cell-specific (or different) transmit and / or receive characteristics of a TCI state with the same value for another cell. In other words, the TCI state ID# for cell 1 may contain different information than the TCI state ID# for cell 2. Generally, a TCI state may contain any appropriate parameters related to beam or transmit.

[0074] In one embodiment, the configuration of the TCI status list (or TCI status pool) associated with each candidate cell may be provided to the UE510, for example, during the LTM preparation phase. In one example, the TCI status list may be provided / updated using RRC. In one example, such a configuration may be part of a baseline RRC configuration that the UE510 can maintain and / or keep across multiple cell transitions. As shown in Figure 6, the configuration of the TCI status list for each configured LTM candidate cell may be provided under a CellGroupConfig or as part of another RRC configuration, and each LTM cell may be referenced using the LTM candidate cell identifier within the serving cell. In one example, each TCI status list may be referenced using the LTM candidate cell identifier (or LTM index, or LTM configuration ID) within the serving cell. In another example, the configuration of the TCI status list corresponding to each configured LTM candidate cell may be provided outside of any CellGroupConfig. In yet another example, the configuration of the TCI status list corresponding to each configured LTM candidate cell may be provided using RRC signaling. For example, LTM-specific configuration messages can be used to provide LTM candidate cell TCI state configuration.

[0075] The example in Figure 6 is for illustrative purposes only. In the embodiment, the number of LTM candidate cells and / or LTM indices shown in the configuration may vary and may differ from those shown in Figure 6.

[0076] Returning to Figure 5, in 504, the serving cell 520 sends a MAC-CE (Candidate Cell / LTM Cell TCI State Activation MAC-CE or generally a message) that includes an indicator of the candidate cell (e.g., an adjacent cell / LTM cell as described above with reference to Figure 4) and the activation of one or more TCI states for the candidate cell, and the UE 510 receives the MAC-CE. The MAC-CE may include a candidate cell ID to indicate the candidate cell. One or more TCI states activated for the candidate cell may be called the activated TCI state list (candidate cell-specific activated TCI list). One or more activated TCI states may include at least a subset of one or more TCI configuration states configured for the candidate cell in 502. In some examples, the serving cell 520 may exclude at least one of the one or more configured TCI states for the candidate cell; that is, at least one of the configured TCI states for the candidate cell may remain inactive. In other examples, the serving cell 520 may activate all of the one or more configured TCI states for the candidate cell. MAC-CE for TCI state activation can be in various formats, as described below with reference to Figure 7, for example.

[0077] Figure 7 shows an exemplary TCI state-activated MAC-CE700 for a candidate cell to support LTM. As shown in Figure 7, the MAC-CE700 includes a Serving Cell Identifier (ID) / LTM ID (e.g., LTM Index, LTM Configuration ID, or any ID that identifies the candidate / LTM cell) field 702, an S / L field 704, and a TCI state list field 710. The Serving Cell ID / LTM ID field 702 may have a length of 5 bits and may indicate a Serving Cell ID that identifies the serving cell or an LTM ID that identifies the candidate cell to which the MAC-CE700 applies. The LTM ID may also be called an LTM Cell ID, LTM Candidate Cell ID, or LTM Configuration ID. The S / L field 704 may have a length of 1 bit and may indicate whether the Serving Cell ID / LTM ID field 702 contains a value for the Serving Cell ID or LTM ID (for the candidate cell) to which the MAC-CE700 applies. For example, a bit value of 1 in the S / L field 704 may indicate that the Serving Cell ID / LTM ID field 702 contains a Serving Cell ID, and a bit value of 0 in the S / L field 704 may indicate that the Serving Cell ID / LTM ID field 702 contains an LTM ID, and vice versa. The TCI state list field 710 may have a variable length and may contain a list of one or more TCI states to be activated for the cell identified by the Serving Cell ID / LTM ID field 702 to which MAC-CE 700 applies. That is, if the Serving Cell ID / LTM ID field 702 indicates a Serving Cell ID, the TCI state list field 710 contains TCI states to be activated for the Serving Cell identified by the Serving Cell ID. Alternatively, if the Serving Cell ID / LTM ID field 702 indicates an LTM ID, the TCI state list field 710 contains TCI states or TCI state IDs to be activated for the candidate cell identified by the LTM ID.

[0078] As further shown in Figure 7, the MAC-CE700 includes several reserved fields 701 labeled R, a DL bandwidth portion (BWP) ID field 703, a UL BWP ID field 705, several Pi fields 706 labeled P1 to P8 (for example, i varies from 1 to 8), and several D / U fields 707 labeled D / U. To avoid confusion in the diagram in Figure 7, only one of the reserved fields is labeled 701, only one of the Pi fields is labeled 706, and only one of the D / U fields is labeled 707.

[0079] In one example, if the indicated serving cell in the Serving Cell ID / LTM ID (e.g., LTM Index, LTM Configuration ID, or any ID that identifies a candidate / LTM cell) field 702 is configured as part of simultaneousU-TCI-UpdateList1, simultaneousU-TCI-UpdateList2, simultaneousU-TCI-UpdateList3, or simultaneousU-TCI-UpdateList4 as defined in the 3GPP TS 38.331 document, then MAC-CE700 applies to the serving cell to all serving cells in the set of simultaneousU-TCI-UpdateList1, simultaneousU-TCI-UpdateList2, simultaneousU-TCI-UpdateList3, or simultaneousU-TCI-UpdateList4, respectively.

[0080] The DL BWP field 703 indicates the DL BWP to which MAC-CE700 is applied as the code point for the DCI bandwidth partial indicator field specified in the 3GPP TS 38.212 document. The length of the DL BWP ID field 703 is 2 bits.

[0081] The UL BWP field 705 indicates the UL BWP that MAC-CE700 applies as the code point for the DCI bandwidth partial indicator field specified in the 3GPP TS 38.212 document. The length of the UL BWP ID field 705 is 2 bits.

[0082] The Pi field 706 indicates whether each TCI code point has multiple TCI states or a single TCI state. If the Pi field 706 is set to 1, it indicates that the i-th TCI code point contains both DL TCI and UL TCI states. If the Pi field 706 is set to 0, it indicates that the i-th TCI code point contains either a DL / Joint TCI state or an UL TCI state. The code point to which a TCI state is mapped is determined by its orthographic position within all TCI state ID fields in the TCI state list field 710.

[0083] The D / U field 707 indicates whether the TCI state IDs within the same octet are for joint / downlink or uplink TCI states. If this field is set to 1, the TCI state IDs within the same octet are for uplink, and vice versa.

[0084] The TCI state ID in the TCI state list field 710 indicates a TCI state identified by a TCI-StateId as defined in the 3GPP TS 38.331 document. When the D / U field 707 is set to 1, a 7-bit TCI state ID, i.e., a TCI-StateId as defined in the 3GPP TS 38.331 document, is used. When the D / U field 707 is set to 0, the most significant bit of the TCI state ID is considered a reserved bit, and the remaining 6 bits represent the UL-TCIState-ID specified in the 3GPP TS 38.331 document. In some examples, the maximum number of activated TCI states can be 16.

[0085] The reserved field 701 is a reserved bit and can be set to 0.

[0086] Those skilled in the art will understand simultaneousU-TCI-UpdateList1, simultaneousU-TCI-UpdateList2, simultaneousU-TCI-UpdateList3, simultaneousU-TCI-UpdateList4, DL BWP, and UL BWP.

[0087] According to aspects of this disclosure, MAC-CE700 may be part of an integrated TCI framework configured to support LTM. For example, MAC-CE700 may be used to carry inter-cell beam indexing and / or subsequent communications for intra-cell and / or inter-cell beam management for LTM-based cell switching by UEs (e.g., UE150, 310, 410, and / or 510) in a new target cell, as will be discussed in more detail below.

[0088] For example, an integrated TCI state activation / deactivation MAC-CE, as defined in the 3GPP TS 38.321 document, may be modified as shown in MAC-CE700 in Figure 7. In one embodiment, the serving cell ID in the integrated TCI state activation / deactivation MAC-CE may be reinterpreted to include either a serving cell ID or an LTM configuration ID (e.g., an ID indicating an LTM candidate cell containing the current serving cell). The integrated TCI state activation / deactivation MAC-CE may include bit fields (e.g., S / L field 704) on which interpretation may depend. For example, a bit field in the MAC CE may indicate whether the TCI state activation is for a serving cell (serving cell ID (S)) or for an LTM candidate cell (LTM configuration index (L)). If the bit field indicates S, activation is for the serving cell ID and serving cell beam management (e.g., for intra-cell / inter-cell beam management); or if the bit field indicates L, the active TCI state in MAC-CE is for the LTM candidate cell indicated by the field (e.g., including the current serving field).

[0089] The example in Figure 7 is for illustrative purposes only. Generally, MAC-CE can be used to provide activation for one or more LTM candidate cells or candidate cell IDs.

[0090] As described above, the candidate cell TCI state activation MAC-CE can be in various formats. In one embodiment, a first field in the MAC-CE (e.g., Serving Cell ID / LTM ID field 702) refers to the identification information or candidate cell configuration of a candidate cell that is conditionally present or conditionally interpreted when the MAC-CE is received. For example, the first field in the MAC-CE is interpreted in a manner based on the value of a bit field in the MAC-CE (e.g., S / L field 704). For example, one value of the bit field (e.g., the first value) may indicate that the UE should interpret the information in the first field of the MAC-CE as a Serving Cell ID, and the other value of the bit field (e.g., the second value) may indicate that the UE should interpret the information in the first field of the MAC-CE as an LTM candidate cell configuration ID or additional PCI value or any other identification information used to indicate an LTM candidate cell. For example, the first value may be 1 and the second value may be 0, or vice versa. In another example, the value of a bit field in the MAC-CE (for example, 1) may indicate that the UE reads the first field in the MAC-CE as an LTM candidate cell configuration ID or additional PCI value or any other identifying information used to indicate an LTM candidate cell. In other words, the MAC-CE can utilize a bit field to indicate that there is information within the MAC-CE that identifies an LTM candidate cell.

[0091] Generally, a candidate cell TCI state activation MAC-CE may include a first field and a second field to indicate whether the information in the first field (e.g., cell ID or TCI state ID) is for a serving cell or a candidate cell.

[0092] Returning to Figure 5, at 506, the UE 510 and the serving cell 520 can communicate with each other. In some examples, the serving cell 520 can transmit a signal measurement configuration (e.g., an L1-RSRP measurement configuration for SSB, CSI-RS, DL RS and / or any RS) which the UE 510 can receive. In response, the UE 510 may transmit a signal measurement report as described above, which the serving cell 520 can receive. In general, the serving cell 520 can serve the UE 510 by communicating with the UE 510 at 506 any appropriate communication signal.

[0093] In 508, the serving cell 520 transmits a cell switching command via lower-layer signaling (e.g., via media access control (MAC) or physical layer signaling, L1 / L2 signaling) indicating a candidate cell (in 504, one or more TCI states are activated) as the target cell (indicated by the target cell 530), which the UE 510 receives. For example, the cell switching command may include an index of the target cell ID corresponding to the candidate cell ID in MAC-CE in 504. The serving cell 520 may select a candidate cell from a set of candidate cells using any appropriate mechanism, for example, based on the best signal quality from the candidate cells.

[0094] In 509, in response to a cell switching command, the serving cell 520 may perform a handover of the UE 510 to the target cell 530. The handover may include transferring information and / or any pending data related to the UE 510 to the target cell.

[0095] In 512, in response to the cell switching command, UE510 switches communication to target cell 530. UE510 communicates with target cell 530 by applying at least one of one or more TCI states activated in 504.

[0096] In one embodiment, the TCI state activation of a candidate cell in 504 may include a single (only one) activated TCI state, and the cell switch command in 508 may exclude a TCI state indicator or indicate that no TCI state is provided. In this regard, when UE 510 receives a cell switch command without an indicator of a TCI state or no TCI state being provided, UE 510 considers the cell switch command to implicitly indicate a single activated TCI state. Thus, UE 510 may apply a single activated TCI state in 512 for communication with the target cell 530. In another embodiment, if the TCI state activation for a candidate cell in 504 includes a single (only one) TCI state and the cell switch command in 508 includes an indicator of a TCI state, UE 510 may consider a TCI state to be indicated (for cell switching) when the TCI state in the cell switch command is the same as (or matches) the activated TCI state ID.

[0097] In one embodiment, UE510 may consider an activated TCI state for an LTM cell received in a MAC-CE (for example, in 504) to be valid at the time of reception of the MAC-CE. In one embodiment, when UE510 subsequently receives another MAC-CE that activates (or updates) a TCI state for the same LTM cell, the previously activated TCI state may be updated with the TCI state activated by the latest MAC-CE.

[0098] In one embodiment, the UE510 may be configured to receive one or more MAC-CEs that provide TCI state activations. The configuration may be based on UE capability, which may indicate, for example, how many MAC-CEs associated with different LTM candidate cells can be provided to the UE510 and / or how many cells can be associated with the list of activated TCI states, as described herein. In one example, there may be a maximum number (or threshold number) of N activated TCI states across different LTM candidate cells supported by the UE510. In this example, the value N may include active TCI states used for cell beam management in the current serving cell. In other words, the value N may be the total number of active TCI states supported by the UE510 for the current serving cell and any other LTM candidate cells. In another example, the value N may exclude active TCI states used for cell beam management in the current serving cell. In other words, N may be the total number of active TCI states supported by the UE510 for the LTM candidate cells.

[0099] In some embodiments, a DCI-based beam index may be used to indicate a cell switching command (for example, in 508) when MAC-CE-based TCI state activation is provided for an LTM, as described herein. In a first example, the DCI-based beam index may include an LTM index, an LTM configuration ID, etc. (for example, an additional PCI index which is a logical index for the list of PCIs configured as LTM candidates) and a TCI code point mapping to the TCI index. Referring to the exemplary TCI state activation MAC-CE 700 shown in Figure 7, each of the TCI state IDs in the TCI state list field 710 may be referenced by a TCI code point in the order of the TCI state IDs in the TCI state list field 710. That is, assuming each TCI code point contains one TCI state, a TCI code point with a value of 0 may refer to (or point to) TCI state ID 1 in the TCI state list field 710, a TCI code point with a value of 1 may refer to (or point to) TCI state ID 2 in the TCI state list field 710, and so on. In the second example, the DCI-based beam index may include two TCI code point values ​​to indicate an activated TCI state ID 2 (in the TCI state list field 710) for cell switching to a candidate cell identified by the LTM ID in the serving cell ID / LTM field 702. In the third example, the DCI-based beam index may include an index of the LTM candidate pool / cell ID and TCI code point that refers to at least one of the one or more activated TCI states in the TCI state list field 710. In the third example, the DCI-based beam index may include an LTM flag indicating that the DCI beam index points to the LTM candidate cell TCI state list and not to the serving cell beam management TCI state list.

[0100] Generally, cell switching commands can be carried in DCI or MAC-CE. DCI or MAC-CE may include an index of the candidate cell (as the target cell for cell switching) and a TCI code point. The TCI code point may refer to at least one TCI state from a list of one or more TCI states activated for the candidate cell, and activation may be based on the signaled candidate LTM configuration ID (or similar) in the candidate cell TCI state activation MAC-CE.

[0101] In one embodiment, upon receiving and applying a cell switch command, UE510 may decide to use the activated TCI state list (activated in 504) for the new serving cell (e.g., target cell 530) to which the cell switch command is applied. For example, when UE510 enters a new target cell (e.g., target cell 530), UE510 considers the "activated TCI state list" to be valid for intra-cell beam management. In other words, the list is the activated TCI state list for the current serving cell (e.g., PCell) from which UE510 performed the switch. The activated TCI states in the activated TCI state list may refer to TCI states provided within the RRC configuration. For example, UE maintains a list of activated TCI states after a cell switch and a list of TCI states (RRC configuration) in which the TCI states were activated. In another example, if the activated TCI state list (activated in 506) for serving cell 520 is associated with multiple PCIs, when UE 510 enters a new target cell, UE 510 considers the "activated TCI state list" to be valid for inter-cell beam management and intra-cell beam management. Beam management can generally refer to processes and / or mechanisms related to beam formation, control, and / or detection. Beam management can include various stages, for example, during initial access by the UE or while the UE is in connected mode. In inter-cell beam management, the UE may be configured to communicate with a cell having a different PCI than the serving cell while maintaining a connection to the serving cell.

[0102] In one embodiment, when UE510 applies MAC-CE used to activate a TCI state for an LTM cell (for example, in 504), the activated TCI state is considered valid until a cell switching command is applied in 508. For the cell from which the cell switching is triggered / signaled (e.g., target cell 530), the list (of activated TCI states) becomes the intra-cell (or inter-cell) beam management list. For other cells, the TCI states are not considered active (i.e., they are deactivated).

[0103] In one embodiment, UE510 may maintain a list of TCI states activated by the source cell (previous serving cell 520) while operating in the target cell 530. The list of activated TCI states may be for the previous serving cell 520, any previous serving cell, or other candidate cells. For example, upon receiving the list of activated TCI states, UE510 may store the list in its memory (e.g., memory 1150), and the stored list of activated TCI states may not be overwritten or deleted. In one embodiment, whether the active TCI states are maintained and / or retained in UE510 after a cell switch may be configured. The configuration may be cell-specific. For example, after UE510 enters the target cell 530, UE510 may receive a configuration (e.g., from serving cell 520) or indicator indicating whether the list of active TCI states (for the target cell and / or other candidate cells whose TCI states were activated) should be deactivated or retained. In one embodiment, the UE510 may receive this configuration or indicator as part of a cell switching command (for example, during DCI) or as an RRC configuration (for example, an RRC preconfiguration).

[0104] In a further embodiment, the current serving cell ID (which may also be identified by an LTM configuration index or LTM index) may be referenced by a MAC-CE that activates a TCI state for intra-cell beam management. In one example, if the current serving cell 520 is referenced in a MAC-CE that activates a TCI state using an LTM-specific index (for example, the current serving cell is called or referenced by a candidate cell (LTM) index), then UE510 determines that the TCI state provided in the activating MAC-CE is activated when UE510 applies a cell switch to a new target cell 530. In other words, a serving cell may be configured and activated with TCI states for LTM operation (and simultaneously, a serving cell may have a list of activated TCI states for intra-cell beam management).

[0105] The example in Figure 5 is for illustrative purposes only. In the embodiment, the number of candidate cell TCI state activation MAC-CEs from serving cell 520 to UE 510, the number of candidate cells for TCI state activation in each candidate cell TCI state activation MAC-CE, and / or the number of TCI states for activation for each candidate cell may vary and may differ from those illustrated in Figure 5. In some examples, serving cell 520 may send one MAC-CE to activate a TCI state for each LTM candidate cell. In other examples, serving cell 520 may send one MAC-CE to activate TCI states for multiple LTM candidate cells. In some examples, the candidate cell TCI state activation MAC-CE may include a candidate cell-specific TCI state activation list for each candidate cell. In some examples, the candidate cell TCI state activation MAC-CE may include a candidate cell list containing multiple candidate cell IDs and a separate TCI state activation list for each of the multiple candidate cells. In some examples, the candidate cell TCI state activation MAC-CE may be a modified or extended integrated TCI state activation MAC-CE as defined by 3GPP. In other examples, the candidate cell TCI state activation MAC-CE may be a MAC-CE (or generally a message) identified by an ID specific to TCI state activation for LTM candidate cells. Figure 8 is a flowchart of exemplary operation for UEs such as UE150, 310, 410, and / or 510 for LTM. The operation in Figure 8 may include a mechanism similar to that described above with reference to Figures 5-7. As shown, Figure 8 includes several enumerated steps, but the modes of operation in Figure 8 may include additional steps before, after, and between the enumerated steps. In some modes, one or more of the enumerated steps may be omitted or performed in a different order.

[0106] In 802, the operation includes receiving the MAC-CE, the candidate cell index, and the activation of one or more TCI states for the candidate cell from the serving cell. In the example, the serving cell may correspond to serving cell 520. In the example, the MAC-CE may be received from serving cell network devices such as network device 110, MN320, PCell322 (e.g., PCell network node), CU, DU, and / or network devices 420, 430, 440.

[0107] In one embodiment, the MAC-CE includes a first field and a second field to indicate whether the information in the first field is for a serving cell or a candidate cell. For example, the second field may be similar to the S / L field 704 in MAC-CE 700 in Figure 7 to give a conditional interpretation of the first field. In one embodiment, the MAC-CE includes a first value and a second value, where the first value indicates that a candidate cell is identified. In one embodiment, the MAC-CE includes a value to indicate that one or more TCI states are activated for a candidate cell. In one embodiment, the MAC-CE includes a candidate cell-specific TCI state list, which includes an indicator of the candidate cell (e.g., LTM ID) and the activation of one or more TCI states (for the candidate cell).

[0108] In 804, the operation includes receiving a cell switching command from the serving cell via lower-layer signaling, indicating a candidate cell as the target cell. The lower-layer signaling includes at least one of L1 signaling or L2 signaling.

[0109] In one embodiment, receiving a cell switch command includes receiving a DCI that includes an index of a candidate cell and a TCI code point that references at least one of one or more TCI states. In another embodiment, receiving a cell switch command includes receiving a DCI that includes an index of a candidate cell activation TCI state list that includes a candidate cell and a TCI code point that references at least one of one or more TCI states. In one embodiment, receiving a cell switch command includes receiving a DCI that includes a reference to at least one of one or more TCI states and an index that at least one of one or more TCI states is for a candidate cell.

[0110] In 806, the operation includes switching communication to a target cell in response to a cell switching command. Switching to a target cell includes communicating with the target cell by applying at least one of one or more TCI states. In one embodiment, carrier aggregation may be used for communication with the UE as described above with reference to Figure 3 (when the target cell is a SCell). In such an embodiment, the serving cell may be a PCell, and the candidate cell may be a candidate PCell. Thus, switching communication to a target cell may refer to switching communication from a serving PCell to a target PCell. In another embodiment, the serving cell may be a PCell, and the candidate cell may be a candidate PCell. Thus, switching communication to a target cell may refer to switching communication from a serving PCell to a target SCell.

[0111] In one embodiment, the cell switching command in 804 further includes a reference (e.g., a TCI code point) to at least one of one or more TCI states (activated in 802). In a further example, it may be configurable whether the cell switching command provides a beam indicator / TCI state indicator in the form of a TCI code point or a TCI state ID. In one example, the cell switching command may have an indicator of whether at least one TCI state is indicated using a TCI code point or a TCI state ID (or more IDs). In one example, if separate TCI states (separate TCI states for uplink and downlink) are indicated by the cell switching command, the cell switching TCI state IDs are for downlink and uplink. The TCI states may be listed in the order DL TCI State ID, UL TCI State ID. In one example, the DCI scheduling a cell switching command may include a TCI code point indicating the TCI state for the target cell. The cell switching command (in any embodiment) providing an indicator of the TCI state (e.g., a beam indicator) may point to any MAC CE that activates the TCI state for LTM-based beam indication (and / or for further communication in the target cell).

[0112] In one embodiment, a cell switching command in 804 further includes a reference to a TCI state, and the application of at least one of one or more TCI states is based on the consistency between the TCI state referenced in the cell switching command and at least one of one or more TCI states. For example, if a cell switching command indicates TCI state ID 2, and one or more activated TCI states include the same TCI state ID 2, the UE may apply TCI state ID 2 for communication with the target cell. However, if a cell switching command indicates TCI state ID 2, and one or more activated TCI states do not include TCI state ID 2, the UE may not apply TCI state ID 2 as indicated by the cell switching command. In this case, the UE may decide to trigger a random access procedure on the candidate cell. Alternatively, the UE may use TCI state ID 2 as the targeted / indicated TCI state ID, determine that TCI state ID (#2) is not a known TCI state to the UE, and further apply a longer beam application time (i.e., the time after which the UE is assumed to use / apply the new TCI state). The beam application time may include performing one or more measurements on the DL RS indicated by the TCI state.

[0113] In one embodiment, the UE further performs intra-cell beam management in a target cell based on one or more TCI states. In another embodiment, one or more TCI states are associated with multiple PCIs, and the UE performs intra-cell and inter-cell beam management in a target cell based on one or more TCI states. Some exemplary operations of beam management may include beam formation, control, and / or detection.

[0114] In one embodiment, the UE may, in 802, further maintain a list of TCI states activated by a serving cell (e.g., a previous source cell) while operating in the target cell. In one embodiment, maintaining a list of TCI states activated by a serving cell while operating in the target cell is based on a configuration that includes an index for maintaining a list of TCI states activated by a previous serving cell. In one embodiment, the configuration is a cell-specific configuration. In one embodiment, a cell switching command in 804 includes a configuration. In another embodiment, the UE may further receive a configuration in an RRC configuration (e.g., a cell-specific RRC configuration).

[0115] In one embodiment, the UE may further transmit an indicator of UE capability (for example, indicating a threshold number of activated TCI states supported by the UE), at least one of the number of one or more TCI states in the MAC-CE for a candidate cell or the number of activated TCI states across multiple cells, based on UE capability.

[0116] In one embodiment, the UE may further receive other MAC-CEs from the serving cell, including an index of one or more TCI states to be activated for the serving cell after switching to the target cell. In one embodiment, the UE may further receive a configuration including an index of one or more candidate cells for low-layer trigger mobility and a TCI state list for each of the one or more candidate cells.

[0117] Figure 9 is a flowchart illustrating the exemplary operation of network devices such as network device 110, MN320, PCell322 (e.g., PCell network node), CU, DU, network devices 420, 430, 440 and / or serving cell 520 (e.g., serving cell network node). The operation in Figure 9 may include mechanisms similar to those described above with reference to Figures 5-7. As shown, Figure 9 includes several enumerated steps, but the mode of operation in Figure 9 may include additional steps before, after, and between the enumerated steps. In some modes, one or more of the enumerated steps may be omitted or performed in a different order.

[0118] In 902, the operation includes sending a MAC-CE to the UE (e.g., UE150, 310, 410, 510) that includes the candidate cell's index and the activation of one or more TCI states for the candidate cell. In one embodiment, the MAC-CE includes a first field and a second field to indicate whether the information in the first field is for a serving cell or for a candidate cell. For example, the second field may be similar to the S / L field 704 in MAC-CE 700 in Figure 7 to give a conditional interpretation of the first field. In one embodiment, the MAC-CE includes a first value and a second value, where the first value indicates that the candidate cell is identified. In one embodiment, the MAC-CE includes a value to indicate that one or more TCI states are activated for the candidate cell. In one embodiment, the MAC-CE includes a candidate cell-specific TCI state list that includes the candidate cell's index (e.g., LTM ID) and the activation of one or more TCI states (for the candidate cell).

[0119] 904, the operation includes sending a cell switching command to the UE via lower-layer signaling, indicating a candidate cell as the target cell. In one embodiment, the cell switching command further indicates a reference to at least one of one or more TCI states (activated in 902). In other embodiments, the cell switching command does not include any additional TCI state indicators or references, and the network device may expect that the UE will utilize one or more TCI states (activated in 902) when it switches to the target cell.

[0120] In 906, the operation includes performing a handover of the UE to the target cell in response to a cell switching command. The handover may include transferring information and / or any pending data related to the UE510 to the target cell.

[0121] Figure 10 shows an exemplary embodiment of a block diagram of exemplary components of a UE or network device. For example, the UE may correspond to UE150, 310, 410, or 510, and the network device may correspond to network device 110, MN320, PCell322 (e.g., PCell network node), network device 420, 430, 440, or serving cell 520 (which may be a network node, CU, or DU). The device includes electronic storage 1110, a processor 1120, memory 1150, and a network interface 1140. Various components may be coupled to communicate with one another. The processor 1120 may be any type of processor, including a single-core central processing unit (CPU), a multi-core CPU, a microprocessor, a digital signal processor (DSP), a system-on-a-chip (SoC), or any other type of processor, and may include any type of processor. The memory 1150 may be a volatile type of memory, such as RAM, or a non-volatile type of memory, such as NAND flash memory. The memory 1150 contains computer-readable instructions that can be executed by the processor 1120, causing the device to perform various operations, including the beam indicators of the LTM described herein (e.g., TCI state pre-activation and / or TCI state indicators).

[0122] The electronic storage 1110 may include any type of electronic storage used to store data, such as hard disk drives, solid-state drives, and / or optical discs, among other types of electronic storage. The electronic storage 1110 stores software instructions for the device to perform its operations, and data related to such operations, such as data related to the 5G NR standard, among other data. The network interface 1140 can implement wireless networking technologies such as 5G NR, Wi-Fi 6, and / or other wireless networking technologies, and may include one or more arrays of radiating elements, as described in relation to Figures 1 to 7.

[0123] The components shown in Figure 10 are merely examples, and those skilled in the art will understand that the apparatus may include other components not illustrated, and may include any multiple of the illustrated components. Such embodiments and other embodiments are intended to be within the scope of this disclosure.

[0124] Further embodiments of this disclosure include the following examples:

[0125] Example 1 is a method performed by a user device, comprising the steps of: receiving a media access control control element (MAC-CE) from a serving cell, which includes an index of a candidate cell and the activation of one or more transmit configuration indicator (TCI) states for the candidate cell; receiving a cell switching command from the serving cell via lower layer signaling (e.g., via media access control (MAC) or physical layer signaling, L1 / L2 signaling) indicating the candidate cell as a target cell; and switching communication to the target cell in response to the cell switching command, wherein the switching step includes communicating with the target cell by applying at least one of the one or more TCI states.

[0126] In Example 2, the MAC-CE may optionally include a first field, and the second field may optionally include a feature indicating whether the information in the first field is for the serving cell or for the candidate cell.

[0127] In Example 3, the method in Example 1 or 2 may optionally include a feature in which the MAC-CE includes a first value and a second value indicating that the first value identifies the candidate cell.

[0128] In Example 4, the MAC-CE may optionally include a feature that includes a candidate cell-specific TCI state list containing one or more of the TCI states, as can be selected from any one of the methods in Examples 1 to 3.

[0129] In Example 5, any one of the methods in Examples 1 to 4 may optionally include a feature in which the cell switching command further includes a reference to at least one of the one or more TCI states.

[0130] In Example 6, any one of the methods in Examples 1 to 5 may optionally include a feature in which the step of receiving the cell switching command includes a step of receiving downlink control information (DCI) which includes an index of the candidate cell and a TCI code point that refers to at least one of the one or more TCI states.

[0131] In Example 7, any one of the methods in Examples 1 to 5 may optionally include a feature in which the step of receiving the cell switching command includes receiving downlink control information (DCI) which includes an index of a candidate cell activation TCI list containing the candidate cell and a TCI code point that refers to at least one of one or more TCI states.

[0132] In Example 8, any one of the methods in Examples 1 to 5 may optionally include a feature in which the step of receiving the cell switching command includes a step of receiving downlink control information (DCI) which includes a reference to at least one of the one or more TCI states and an indicator that at least one of the one or more TCI states is for the candidate cell.

[0133] In Example 9, the cell switching command further includes a reference to a TCI state, and the communication with the target cell using at least one of the TCI states may optionally include features based on a match between the TCI state referenced in the cell switching command and at least one of the one or more TCI states, as can be any one of the methods in Examples 1 to 7.

[0134] In Example 10, any one of the methods in Examples 1 to 9 may optionally include a feature that includes performing intra-cell beam management in the target cell based on one or more TCI states.

[0135] In Example 11, any one of the methods in Examples 1 to 9 may optionally include a further step of performing at least one of intra-cell management or inter-cell management in the target cell based on one or more TCI states, where one or more TCI states are associated with a plurality of physical cell identifiers (PCIs).

[0136] In Example 12, any one of the methods in Examples 1 to 11 may optionally include a feature that includes maintaining the TCI state list activated by the serving cell while operating in the target cell.

[0137] In Example 13, the step of maintaining the TCI state list activated by the serving cell while operating in the target cell may optionally include a feature based on a configuration that includes an index for maintaining the TCI state list activated by the serving cell, as is the case with any one of Examples 1 to 12.

[0138] In Example 14, the feature that the configuration is cell-specific can be optionally included in any one of the methods from Examples 1 to 13.

[0139] In Example 15, any one of the methods in Examples 1 to 14 may optionally include a feature that includes receiving the configuration in a radio resource control (RRC) configuration.

[0140] In Example 16, the cell switching command may optionally include the feature described above in any one of the methods from Examples 1 to 14.

[0141] Example 17 includes a step of transmitting an indicator of UE capability (e.g., indicating a threshold number of activated TCI states supported by the UE), wherein at least one of the number of TCI states activated in the MAC-CE for the candidate cell, or the number of TCI states activated across multiple cells in the user equipment device, may optionally include a feature based on the user equipment capability in any one of Examples 1 to 6.

[0142] In Example 18, any one of the methods in Examples 1 to 17 may optionally include a feature that includes receiving from the serving cell other MAC-CEs, which include an index of a candidate cell ID corresponding to the serving cell and one or more TCI states that are activated for the serving cell after switching to the target cell.

[0143] In Example 19, any one of the methods in Examples 1 to 18 may optionally include a feature that includes receiving a configuration comprising an index for one or more candidate cells for low-layer trigger mobility and a TCI state list for each of the one or more candidate cells.

[0144] In Example 20, the feature that the serving cell is a primary cell can be optionally included in any one of the methods from Examples 1 to 19.

[0145] Example 21 includes a device comprising at least one processor and at least one memory for storing instructions, wherein, when the instructions are executed by at least one of the processors, they cause a user device to execute at least one of the methods of Examples 1 to 20.

[0146] Example 22 includes an apparatus characterized by comprising means for performing at least one of the methods of Examples 1 to 20.

[0147] Example 23 includes a non-temporary computer-readable medium containing program code, wherein the program code, when executed by one or more processors, causes one or more of the processors to execute at least one of the methods described in Examples 1 to 20.

[0148] Example 24 includes a method performed by a serving cell network device, comprising the steps of: transmitting a media access control control element (MAC-CE) to a user device, which includes an index of a candidate cell and the activation of one or more transmit configuration indicator (TCI) states for the candidate cell; transmitting a cell switching command to the user device via lower-layer signaling, which designates the candidate cell as a target cell; and performing a handover of the user device to the target cell in response to the cell switching command.

[0149] In Example 25, the method of Example 24 may optionally include a feature in the MAC-CE that includes a first field and a second field indicating whether the information in the first field is for the serving cell or for the candidate cell.

[0150] In Example 26, the method of Example 24 or 25 may optionally include a feature in which the MAC-CE includes a first value and a second value indicating that the first value identifies the candidate cell.

[0151] In Example 27, the MAC-CE may optionally include a feature that includes a candidate cell-specific TCI state list containing one or more of the TCI states, as can be selected from any one of the methods in Examples 24 to 26.

[0152] In Example 28, any one of the methods in Examples 24 to 27 may optionally include a feature in which the cell switching command further includes a reference to at least one of the one or more TCI states.

[0153] In Example 29, any one of the methods in Examples 24 to 28 may optionally include a feature in which the step of transmitting the cell switching command includes transmitting downlink control information (DCI) which includes an index of the candidate cell and a TCI code point that refers to at least one of the one or more TCI states.

[0154] In Example 30, any one of the methods in Examples 24 to 28 may optionally include a feature in which the step of sending the cell switching command includes sending downlink control information (DCI) which includes an index of a candidate cell activation TCI list containing the candidate cell and a TCI code point that refers to at least one of one or more TCI states.

[0155] In Example 31, any one of the methods in Examples 24 to 28 may optionally include a feature in which the step of transmitting the cell switching command includes transmitting downlink control information (DCI) which includes a reference to at least one of the one or more TCI states and an indicator that at least one of the one or more TCI states is for the candidate cell.

[0156] In Example 32, any one of the methods in Examples 24 to 31 may optionally include a feature that includes transmitting a configuration that includes an indicator of whether the user device retains the activated TCI state list that was activated after switching to the target cell.

[0157] In Example 33, the feature that the configuration is an RRC configuration can be optionally included in any one of the methods in Examples 24 to 32.

[0158] In Example 34, the feature that the configuration is cell-specific can be optionally included in any one of the methods from Examples 24 to 33.

[0159] In Example 35, any one of the methods in Examples 24 to 33 may optionally include a feature in the cell switching command that includes an indicator of whether the user device retains the activated TCI state list that was activated after switching to the target cell.

[0160] In Example 36, any one of the methods in Examples 24 to 35 may optionally include a feature that includes receiving an indicator of UE capability (e.g., a threshold number of activated TCI states supported by the UE) from the UE, and configuring several TCI states to be activated across one or more cells for the UE based on the UE capability.

[0161] In Example 37, any one of the methods in Examples 24 to 36 may optionally include a feature of sending another MAC-CE to the UE, which includes an index of a candidate cell ID corresponding to the serving cell and one or more TCI states that are activated for the serving cell after switching to the target cell.

[0162] In Example 38, any one of the methods in Examples 24 to 37 may optionally include a feature that includes transmitting a configuration comprising an index for one or more candidate cells for low-layer trigger mobility and a TCI state list for each of the one or more candidate cells.

[0163] Example 39 includes a device comprising at least one processor and at least one memory for storing instructions, wherein, when the instructions are executed by at least one of the processors, the device causes the network device to execute at least one of the methods in Examples 24 to 38.

[0164] Example 40 includes an apparatus that includes means for performing at least one of the methods of Examples 24 to 38.

[0165] Example 41 includes a non-temporary computer-readable medium containing program code, wherein the program code, when executed by one or more processors, causes one or more of the processors to execute at least one of the methods described in Examples 24 to 38.

[0166] The embodiments and aspects disclosed herein are examples of the disclosure and can be embodied in various forms. For example, while some embodiments herein are described as separate embodiments, each embodiment herein can be combined with one or more other embodiments herein. Certain structural and functional details disclosed herein should not be construed as limiting, but rather as representative grounds for teaching those skilled in the art to use the disclosure in various ways in virtually any appropriately detailed structure. Similar reference numerals may refer to the same or identical elements throughout the description of the drawings.

[0167] The phrases “in a certain manner,” “in a certain manner,” “in various manners,” “in some manners,” and “in other manners” may each refer to one or more of the same or different manners provided for in this disclosure. The phrase “multiple” may refer to two or more.

[0168] The phrases “in one embodiment,” “in one embodiment,” “in various embodiments,” “in some embodiments,” or “in other embodiments” may each refer to one or more of the same or different embodiments provided herein. The phrase “A or B” means “(A), (B), or (A and B).” The phrase “at least one of A, B, or C” means “(A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).”

[0169] Any method, program, algorithm, or code described herein can be translated into or expressed in a programming language or computer program. As used herein, the terms “programming language” and “computer program” include, but are not limited to, any language used to specify instructions to a computer, including, as well as, as any language used to specify instructions to a computer, including, as well as, as any language and its derivatives, such as Assembler, Basic, Batch file, BCPL, C, C+, C++, Delphi, Fortran, Java®, JavaScript®, machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, meta-languages ​​that themselves specify programs, such as Visual Basic, and all first, second, third, fourth, fifth, or further generations of computer languages. Databases and other data schemas, as well as any other meta-languages, are also included. No distinction is made between languages ​​that are interpreted, compiled, or that use both compiled and interpreted approaches. No distinction is made between compiled versions and source versions of a program. Therefore, a reference to a program, in which a programming language can exist in multiple states (source, compiled, object, or linked, etc.), is a reference to any and all of such states. A reference to a program may encompass the actual instructions and / or the intent of those instructions.

[0170] While aspects of this disclosure are shown in the drawings, this disclosure is not intended to be limited thereto, as it is as broad as the scope permitted by the art and the specification is intended to be read in the same way. Accordingly, the above description should not be construed as limiting, but merely as an example of a particular aspect. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended herein.

Claims

1. At least one processor, A user device comprising at least one memory for storing instructions, wherein the instructions are executed by at least one processor, at least, The steps include receiving from a serving cell an index of a candidate cell and a media access control element (MAC-CE) which includes activating one or more transmit configuration indicator (TCI) states for the candidate cell, The steps include receiving a cell switching command from the serving cell via lower-layer signaling, indicating the candidate cell as the target cell, A user device that, in response to the cell switching command, causes the user device to perform a step of switching communication with the serving cell to communication with the target cell, wherein the communication with the target cell includes communication with the target cell to which at least one of one or more TCI states is applied.

2. The user device according to claim 1, characterized in that the MAC-CE includes a first field and a second field indicating whether the information in the first field is for the serving cell or for the candidate cell.

3. The user device according to claim 1, characterized in that the MAC-CE includes a first value and a second value indicating that the first value identifies the candidate cell.

4. The user device according to claim 1, characterized in that the MAC-CE includes a list of candidate cell-specific TCI states that represent one or more of the TCI states.

5. The user device according to claim 1, wherein the cell switching command further includes a reference to at least one of the one or more TCI states.

6. When the instruction is executed by at least one of the processors, at least, The user device according to claim 1, characterized in that the user device further causes the user device to perform the step of receiving the cell switching command by receiving downlink control information (DCI) which includes an index of the candidate cell and a TCI code point that refers to at least one of one or more TCI states.

7. When the instruction is executed by at least one of the processors, at least, The user device according to claim 1, characterized in that the user device further causes the user device to perform the step of receiving the cell switching command by receiving downlink control information (DCI) which includes an index of a candidate cell activation TCI list including the candidate cell and a TCI code point that refers to at least one of one or more TCI states.

8. When the instruction is executed by at least one of the processors, at least, The user device according to claim 1, further causing the user device to perform the step of receiving the cell switching command by receiving downlink control information (DCI) which includes a reference to at least one of the one or more TCI states and an indicator that at least one of the one or more TCI states is for the candidate cell.

9. When the instruction is executed by at least one of the processors, at least, The user equipment device according to claim 1, further characterized in that it causes the user equipment device to perform the step of performing intra-cell beam management in the target cell based on one or more of the TCI states.

10. One or more of the TCI states are associated with a plurality of physical cell identifiers (PCIs), When the instruction is executed by at least one of the processors, at least, The user equipment device according to claim 1, further characterized in that the user equipment device is made to perform the step of performing at least one of intra-cell beam management or inter-cell beam management in the target cell based on one or more TCI states.

11. When the instruction is executed by at least one of the processors, at least, The user device according to claim 1, further characterized in that the user device is made to perform the step of maintaining the TCI state list activated by the serving cell while operating in the target cell.

12. When the instruction is executed by at least one of the processors, at least, The user device is further instructed to perform the step of transmitting an indicator of the user device's capabilities. The user device according to claim 1, wherein at least one of the number of one or more TCI states activated in the MAC-CE for the candidate cell, or the number of TCI states activated across a plurality of cells in the user device, is based on the user device capability.

13. A method performed by a user device, The steps include receiving from a serving cell an index of a candidate cell and a media access control element (MAC-CE) which includes activating one or more transmit configuration indicator (TCI) states for the candidate cell, The steps include receiving a cell switching command from the serving cell via lower-layer signaling, indicating the candidate cell as the target cell, A method characterized by comprising the step of switching communication with the serving cell to communication with the target cell in response to the cell switching command, wherein the communication with the target cell includes communication with the target cell in which at least one of the one or more TCI states is applied.

14. The method according to 13, characterized in that the MAC-CE includes a first field and a second field indicating whether the information in the first field is for the serving cell or for the candidate cell.

15. The method according to 13, characterized in that the MAC-CE includes a first value and a second value indicating that the first value identifies the candidate cell.

16. The method according to 13, characterized in that the MAC-CE includes a list of candidate cell-specific TCI states that represent one or more of the TCI states.

17. The method according to 13, wherein the cell switching command further includes a reference to at least one of one or more TCI states.

18. One or more of the TCI states are associated with a plurality of physical cell identifiers (PCIs), The method according to 13, further comprising the step of performing at least one of intra-cell management or inter-cell management in the target cell based on one or more TCI states.

19. Further steps include sending UE capability indicators, The method according to 13, characterized in that at least one of the number of TCI states activated in the MAC-CE for the candidate cell, or the number of TCI states activated across a plurality of cells in the user equipment, is based on the UE capability.

20. At least one processor, A network device comprising at least one memory for storing instructions, wherein the instructions are executed by at least one of the processors, at least, The steps include transmitting a media access control element (MAC-CE) to a user device, which includes an index of a candidate cell and activating one or more Transmit Configuration Indicator (TCI) states for the candidate cell, The steps include sending a cell switching command indicating the candidate cell as the target cell to the user device via lower-layer signaling, A network device characterized by causing the network device to perform the steps of: responding to the cell switching command, and performing a handover of the user equipment to the target cell.

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