Signaling for multi cell transmission configuration indicator (TCI) activation

Abstract

A method includes receiving, by a user equipment, a configuration for one or more of candidate cells of a plurality of candidate cells, with respective candidate cell configuration identifiers. The user equipment receives a first message, wherein the first message includes a plurality of candidate cell configuration identifier fields, each candidate cell configuration identifier field associated with one of the plurality of candidate cells, wherein the first message further includes at least one transmission configuration indicator, TCI state identifier, per indicated candidate cell configuration identifier of the plurality of candidate cell configuration identifier fields.

Description

SIGNALING FOR MULTI CELL TRANSMISSION CONFIGURATION INDICATOR (TCI) ACTIVATIONFIELD

[0001] Various example embodiments relate generally to wireless networking and, more particularly, to signaling for multi cell transmission configuration indicator (TCI) states for mobility in wireless networking.BACKGROUND

[0002] Wireless networking provides significant advantages for user mobility. A user’s ability to remain connected while on the move provides advantages not only for the user, but also provides greater efficiency and productivity for society as a whole. As user expectations for connection reliability, data speed, and device battery life, become more demanding, technology for wireless networking must also keep pace with such expectations. Accordingly, there is continuing interest in improving wireless networking technology. For that purpose, the cellular standards have developed cell switching on various protocol layers: conventional Layer 3 handovers have been present for several generations. On top of that, a conditional handover was introduced to improve the reliability of handovers. Recent development has contemplated lower-layer handovers known as Layerl / Layer 2 triggered mobility (LTM). Efforts to provide signaling for multi cell transmission configuration indicator (TCI) states may therefore be valuable.SUMMARY

[0003] In an aspect of the present disclosure, a method includes receiving, by a user equipment, a configuration for one or more of candidate cells of a plurality of candidate cells, with respective candidate cell configuration identifiers. The user equipment receives a first message, wherein the first message includes a plurality of candidate cell configuration identifier fields, each candidate cell configuration identifier field associated with one of the plurality of candidate cells, wherein the first message further includes at least one transmission configuration indicator, TCI state identifier, per indicated candidate cell configuration identifier of the plurality of candidate cell configuration identifier fields.

[0004] In an aspect of the method, the TCI state identifiers include a TCI state for one or more codepoints.

[0005] In an aspect of the method, a first TCI state identifier for a first codepoint indicates the TCI state for uplink communication and a second TCI state identifier for a second codepoint indicates the TCI state for downlink communication.

[0006] In an aspect of the method, the first TCI state and the second TCI state are the same.

[0007] In an aspect of the method, the first message further includes an indication of a number of TCI state codepoints activated for each of the indicated one or more candidate cell identifiers.

[0008] In an aspect of the method, the number of TCI state codepoints activated for each of the one or more candidate cells is a configured number.

[0009] In an aspect of the method, the first message further includes a field indicating the number of TCI state codepoints activated for each of the indicated one or more candidate cell identifiers.

[0010] In an aspect of the method, a first candidate cell identifier of the one or more candidate cell identifiers include a first number of TCI state codepoints activated and a second candidate cell identifiers of the one or more candidate cell identifiers include a second number of TCI state codepoints activated.

[0011] In an aspect of the method, the first message further includes a first indicator to indicate the number of first TCI state codepoints activated for the first candidate cell of the one or more candidate cells and a second indicator to indicate the number of second TCI state codepoints activated for the second candidate cell of the one or more candidate cells.

[0012] In an aspect of the method, the first message includes a candidate cell-TCI state indication that a next TCI state identifier is a TCI state of a same candidate cell or a different candidate cell.

[0013] In an aspect of the method, the candidate cell-TCI state indication includes a first value upon the next TCI state identifier being a TCI state of a same candidate cell and wherein the candidate cell-TCI state indication includes a second value upon the next TCI state identifier being a TCI state of a next candidate cell.

[0014] In an aspect of the method, the first message further includes a bandwidth part (BWP) ID, wherein a same BWP ID is indicated for each of the one or more candidate cells.

[0015] In an aspect of the method, the BWP ID is one or more of an uplink (UL) BWP ID or a downlink (DL) BWP ID.

[0016] In an aspect of the present disclosure, a method includes transmitting, by an apparatus, to a user equipment, a configuration for one or more candidate cells of a plurality of candidate cells, with respective candidate cell identifiers. The apparatus transmits a first message to the user equipment, wherein the first message includes a plurality of candidate cell configuration identifier fields, each candidate cell configuration identifier field associated with one of the plurality of candidate cells, wherein the first message further includes at least one transmission configuration indicator, TCI state identifier, per indicated candidate cell configuration identifier of the plurality of candidate cell configuration identifier fields.

[0017] In an aspect of the method, the TCI state identifiers include a TCI state for one or more codepoints.

[0018] In an aspect of the method, a first TCI state identifier for a first codepoint indicates the TCI state for uplink communication and a second TCI state identifier for a second codepoint indicates the TCI state for downlink communication.

[0019] In an aspect of the method, the first TCI state and the second TCI state are the same.

[0020] In an aspect of the method, the first message further includes an indication of a number of TCI state codepoints activated for each of the one or more candidate cells.

[0021] In an aspect of the method, the number of TCI state codepoints activated for each of the one or more candidate cells is a configured number.

[0022] In an aspect of the method, the first message further includes a field indicating the number of TCI state codepoints activated for each of the one or more candidate cells.

[0023] In an aspect of the method, a first candidate cell of the one or more candidate cells includes a first number of TCI state codepoints activated and a second candidate cell of the one or more candidate cells includes a second number of TCI state codepoints activated.

[0024] In an aspect of the method, the first message further includes a first indicator to indicate the number of first TCI state codepoints activated for the first candidate cell of the one or more candidate cells and a second indicator to indicate the number of second TCI state codepoints activated for the second candidate cell of the one or more candidate cells.

[0025] In an aspect of the method, the first message includes a candidate cell-TCI state indication that a next TCI state identifier is a TCI state of a same candidate cell or a different candidate cell.

[0026] In an aspect of the method, the candidate cell-TCI state indication includes a first value upon the next TCI state identifier being a TCI state of a same candidate cell and wherein the candidate cell-TCI state indication includes a second value upon the next TCI state identifier being a TCI state of a next candidate cell.

[0027] In an aspect of the method, the first message further includes a bandwidth part (BWP) ID, wherein a same BWP ID is indicated for each of the one or more candidate cells.

[0028] In an aspect of the method, the BWP ID is one or more of an uplink (UL) BWP ID or a downlink (DL) BWP ID.

[0029] In an aspect of the present disclosure, a user equipment includes at least one processor, and at least one memory storing instructions which, when executed by the at least one processor, cause the apparatus at least to perform any of the foregoing methods.

[0030] In an aspect of the present disclosure, an apparatus includes at least one processor, and at least one memory storing instructions which, when executed by the at least one processor, cause the apparatus at least to perform any of the foregoing methods.

[0031] In an aspect of the present disclosure, a processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, causes the apparatus at least to perform any of the foregoing methods.

[0032] According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Some example embodiments will now be described with reference to the accompanying drawings.

[0034] FIG. 1 is a diagram of an example embodiment of wireless networking between a network system and a user equipment apparatus (UE), according to one illustrated aspect of the disclosure;

[0035] FIG. 2 is a diagram of an example embodiment of transmit and receive beams for wireless networking between a network apparatus and a user equipment apparatus (UE), according to one illustrated aspect of the present disclosure;

[0036] FIG. 3 is a diagram of an example embodiment of a UE sweeping receive beams for synchronization signal block (SSB) bursts, according to one illustrated aspect of the disclosure;

[0037] FIG. 4 is a diagram of an example embodiment of a layer 1 / layer 2 triggered mobility (LTM) scenario, according to one illustrated aspect of the present disclosure;

[0038] FIG. 5 is a diagram of an example embodiment of a contention-based random access procedure, according to one illustrated aspect of the disclosure;

[0039] FIG. 6 is a diagram of an example embodiment of signals and operations among a UE, a central unit (CU), a source distributed unit (DU), and a target DU, relating to LTM, according to one illustrated aspect of the disclosure;

[0040] FIG. 7 is a diagram of an example transmission configuration indicator (TCI) state activation medium access control-control element (MAC-GE) to support LTM, according to one illustrated aspect of the present disclosure;

[0041] FIG. 8 is a diagram of example TCI state activation MAC-CE to support LTM, according to another illustrated aspect of the present disclosure;

[0042] FIG. 9 is a diagram of example TCI state activation MAC-CE to support LTM, according to another illustrated aspect of the present disclosure;

[0043] FIG. 10 is a diagram of example TCI state activation MAC-CE to support LTM, according to another illustrated aspect of the present disclosure;

[0044] FIG. 11 is a diagram of example TCI state activation MAC-CE to support LTM, according to another illustrated aspect of the present disclosure;

[0045] FIG. 12 is a diagram of example TCI state activation MAC-CE to support LTM, according to another illustrated aspect of the present disclosure;

[0046] FIG. 13 is a diagram of example TCI state activation MAC-CE to support LTM, according to another illustrated aspect of the present disclosure;

[0047] FIG. 14 is a diagram of example TCI state activation MAC-CE to support LTM, according to another illustrated aspect of the present disclosure; and

[0048] FIG. 15 is a diagram of example embodiment of components of a UE or of a network apparatus, according to one illustrated aspect of the present disclosure.DETAILED DESCRIPTION

[0049] In the following description, certain specific details are set forth in order to provide a thorough understanding of disclosed aspects. However, one skilled in the relevant art will recognize that aspects may be practiced without one or more of these specific details or with othermethods, components, materials, etc. In other instances, well-known structures associated with transmitters, receivers, or transceivers have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the aspects.

[0050] Reference throughout this specification to “one aspect” or “an aspect” means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, the appearances of the phrases “in one aspect” or “in an aspect” in various places throughout this specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more aspects.

[0051] Embodiments described in the present disclosure may be implemented in wireless networking apparatuses, such as, without limitation, apparatuses utilizing Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-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 Advance, 6G (and beyond) and 802.1 lax (Wi-Fi 6), among other wireless networking systems. The term ‘eLTE’ here denotes the LTE evolution that connects to a 5G core. LTE is also known as evolved UMTS terrestrial radio access (EUTRA) or as evolved UMTS terrestrial radio access network (EUTRAN).

[0052] Because a UE may travel from one area to another area, handover or mobility procedures can be important to support continued communication (without any interruption or at least a minimal interruption) of the UE with the network. In an example, the UE may be configured to monitor certain reference signal(s) (e.g., SSBs, channel state information-reference signals (CSLRSs), DL reference signals (RSs)) from one or more network apparatuses, perform signal measurements of the reference signal(s), and report those signal measurements to the network so that a determination of a handover of the UE to a neighboring cell can be made (e.g., upon a degradation in signal quality is detected). The initiation of a handover may typically be made from the network. In an example of 5G NR, a handover initiation or handover command may be signaled via higher layer signaling, e.g., layer 3 or radio resource control (RRC) signaling. The higher layer signaling may involve the network, and thus can have a high latency. In various situations, a UE may benefit from a more efficient handover procedure triggered via lower layer signaling, e.g.,L1 / L2 signaling, that has a lower latency than the higher layer signaling. As used herein, a handover triggered via lower layer signaling may be referred to as lower layer triggered mobility (LTM). In some instances, a candidate cell for LTM may be referred to as an LTM candidate cell.

[0053] As used herein, the term “cell switch” means and refers to any change of cell, whether the change is triggered via Layer 1 signaling, Layer 2 signaling, and / or Layer 3 signaling, and / or other signaling. The cell switch may be for a terminal device in a RRC connected mode and, thus, the cell switch may involve bidirectional signaling between the terminal device and at least one network node of a radio access network, typically at least a source network node and a target network node of the cell switch. The present disclosure primarily uses LTM as an example of cell switch, but it is intended and shall be understood that the present disclosure may operate with a Layer 3 handover or any cell switch.

[0054] The present disclosure may use the term “serving cell” to refer to a network node or network apparatus (or a portion thereof) that services a UE, may use the term “candidate cell” to refer to a network node or network apparatus (or portion thereof) that is a potential target of a cell switch command, and may use the term “target cell” to refer to a network node or a network apparatus (or portion thereof) that is the target of a cell switch command. In some examples, the LTM target may also be a serving cell (e.g., the target is may be an “SCell,” i.e., a secondary cell in carrier aggregation).

[0055] As used herein, the terms “transmit towards,” “receive from,” and “cooperate with,” (and their variations) include communications that may or may not involve communications through one or more intermediate devices or nodes. The term “acquire” (and its variations) includes acquiring in the first instance or reacquiring after the first instance. The term “connection” may mean a physical connection or a logical connection.

[0056] FIG. 1 is a diagram depicting an example of wireless networking between a network system 100 and a user equipment apparatus (UE) 150. The network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network equipment 130 (e.g., test equipment). The network nodes 120 will be described in more detail below. As used herein, the term “network apparatus” may refer to any component of the network system 100, such as the server 110, the network node 120, the network equipment 130, any component(s) of the foregoing, and / or any other component(s) of the network system 100. Examples of network apparatuses include, without limitation, apparatuses implementing aspects of 5G NR, amongothers. The present disclosure describes embodiments related to 5G NR and embodiments that involve aspects defined by 3rd Generation Partnership Project (3 GPP). However, it is contemplated that embodiments relating to other wireless networking technologies are encompassed within the scope of the present disclosure.

[0057] The following description provides further details of examples of network nodes. In a 5G NR network, a gNodeB (also known as gNB) may include, e.g., a node that provides NR user plane and control plane protocol terminations towards the UE and that is connected via a NG interface to the 5G core (5GC), e.g., according to 3GPP TS 38.300 V16.6.0 (2021-06) section 3.2, which is hereby incorporated by reference herein.

[0058] A gNB supports various protocol layers, e.g., Layer 1 (LI) - physical layer, Layer 2 (L2), and Layer 3 (L3).

[0059] The layer 2 (L2) of NR is split into the following sublayers: Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP) and Service Data Adaptation Protocol (SDAP), where, e.g.: o The physical layer offers to the MAC sublayer transport channels; o The MAC sublayer offers to the RLC sublayer logical channels; o The RLC sublayer offers to the PDCP sublayer RLC channels; o The PDCP sublayer offers to the SDAP sublayer radio bearers; o The SDAP sublayer offers to 5GC quality of service (QoS) flows; o Control channels include broadcast control channel (BCCH) and physical control channel (PCCH).

[0060] Layer 3 (L3) includes, e.g., radio resource control (RRC), e.g., according to 3GPP TS 38.300 VI 6.6.0 (2021-06) section 6, which is hereby incorporated by reference herein.

[0061] A gNB central unit (gNB-CU) includes, e.g., a logical node hosting, e.g., radio resource control (RRC), service data adaptation protocol (SDAP), and packet data convergence protocol (PDCP) protocols of the gNB or RRC and PDCP protocols of the en-gNB, that controls the operation of one or more gNB distributed units (gNB-DUs). The gNB-CU terminates the Fl interface connected with the gNB-DU. A gNB-CU may also be referred to herein as a CU, a central unit, a centralized unit, or a control unit.

[0062] A gNB Distributed Unit (gNB-DU) includes, e.g., a logical node hosting, e.g., radio link control (RLC), media access control (MAC), and physical (PHY) layers of the gNB or en-gNB, and its operation is partly controlled by the gNB-CU. One gNB-DU supports one or multiple cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the Fl interface connected with the gNB-CU. A gNB-DU may also be referred to herein as DU or a distributed unit.

[0063] As used herein, the term “network node” may refer to any of a gNB, a gNB-CU, or a gNB-DU, or any combination of them. A RAN (radio access network) node or network node such as, e.g., a gNB, gNB-CU, or gNB-DU, or parts thereof, may be implemented using, e.g., an apparatus with at least one processor and / or at least one memory with processor-readable instructions (“program”) configured to support and / or provision and / or process CU and / or DU related functionality and / or features, and / or at least one protocol (sub-)layer of a RAN (radio access network), e.g., layer 2 and / or layer 3. Different functional splits between the central and distributed unit are possible. An example of such an apparatus and components will be described in connection with FIG. 12 below.

[0064] The gNB-CU and gNB-DU parts may, e.g., be co-located or physically separated. The gNB-DU may even be split further, e.g., into two parts, e.g., one including processing equipment and one including an antenna. A central unit (CU) may also be called BBU / REC / RCC / C-RAN / V - RAN, 0-RAN, or part thereof. A distributed unit (DU) may also be called RRH / RRU / RE / RU, or part thereof. Hereinafter, in various example embodiments of the present disclosure, a network node, which supports at least one of central unit functionality or a layer 3 protocol of a radio access network, may be, e.g., a gNB-CU. Similarly, a network node, which supports at least one of distributed unit functionality or a layer 2 protocol of the radio access network, may be, e.g., a gNB- DU.

[0065] A gNB-CU may support one or multiple gNB-DUs. A gNB-DU may support one or multiple cells and, thus, could support a serving cell for a user equipment apparatus (UE) or support a candidate cell for handover, dual connectivity, and / or carrier aggregation, among other procedures.

[0066] The user equipment apparatus (UE) 150 may be or include a wireless or mobile device, an apparatus with a radio interface to interact with a RAN (radio access network), a smartphone, an in-vehicle apparatus, an loT device, or a M2M device, among other types of user equipment. Such UE 150 may include: at least one processor; and at least one memory including program code; where the at least one memory and the computer program code are configured to, with theat least one processor, cause the apparatus at least to perform certain operations, such as, e.g., RRC connection to the RAN. An example of components of a UE will be described in connection with FIG. 15. In embodiments, the UE 150 may be configured to generate a message (e.g., including a cell ID) to be transmitted via radio towards a RAN (e.g., to reach and communicate with a serving cell). In embodiments, the UE 150 may generate and transmit and receive RRC messages containing one or more RRC PDUs (packet data units). Persons skilled in the art will understand RRC protocol as well as other procedures a UE may perform.

[0067] With continuing reference to FIG. 1, in the example of a 5G NR network, the network system 100 provides one or more cells, which define a coverage area of the network system 100. As described above, the network system 100 may include a gNB of a 5G NR network or may include any other apparatus configured to control radio communication and manage radio resources within a cell. As used herein, the term “resource” may refer to radio resources, such as a resource block (RB), a physical resource block (PRB), a radio frame, a subframe, a time slot, a sub-band, a frequency region, a sub-carrier, a beam, etc. In embodiments, the network node 120 may be called a base station.

[0068] FIG. 1 provides an example and is merely illustrative of a network system 100 and a UE 150. Persons skilled in the art will understand that the network system 100 includes components not illustrated in FIG. 1 and will understand that other user equipment apparatuses may be in communication with the network system 100.

[0069] FIG. 2 is a diagram of an example embodiment of wireless networking between a network apparatus 210 and a user equipment apparatus (UE) 150. The network apparatus 210 is configured to form beams 220 in multiple directions, and the UE 150 is also configured to form beams 260 in multiple directions. As persons skilled in the art will understand, the capability to beamform in multiple directions may be implemented using arrangements of multiple radiating elements, which may also be referred to as “arrays” of radiating elements. Beamforming (also known as spatial filtering) achieves directional signal transmission or reception by utilizing separate arrays and / or by combining elements in an array in such a way that signals at particular angles result in constructive or destructive interference. Beamforming for a transmission is implemented by controlling the phase and relative amplitude of the transmission signal at each radiating element in an array, in order to create a desired pattern of constructive and destructive interference in a desired wavefront. Beamforming for a reception, in contrast, is implemented bycombining information from different elements of an array in such a way that radiation in a target spatial region is preferentially observed.

[0070] In the illustrated example, the network apparatus 210 (e.g., gNodeB or part thereof) and the UE 150 may each be equipped with one or more antenna panels or antenna arrays with antenna elements that can be configured to perform beamforming in certain spatial directions and / or within certain spatial angular sectors or widths.

[0071] With continuing reference to FIG. 1, various examples of beams 220 are illustrated for the network apparatus 210 and various examples of beams 260 are illustrated for the UE 150. A consequence of using highly directive beams is that some of the network apparatus beams 120 may not be usable with some of the UE beams 160 due to large directional differences. Thus, in embodiments, the UE 150 “sweeps” its beams 260 and the network apparatus 210 “sweeps” its beams 220 to determine which beam-pairing has the highest signal power and, therefore, is best usable for communications. It is possible for beams that are not fully directionally-aligned to have the highest signal power due to various propagating conditions. The sweeps will be described in more detail in connection with FIG. 3. After identifying such a beam pairing, the UE 150 and the network apparatus 210 may use the identified beams to initiate access procedures for the UE 150 to access the network apparatus 210.

[0072] FIG. 3 is a diagram of an example embodiment of a UE sweeping receive beams for SSB bursts. Using the example beams illustrated in FIG. 2, the network apparatus 210 form beams Bl, B2, B3, and B4, successively. Each formation of the beams is referred to as a “burst.” The network apparatus 210 may generate the bursts at intervals for the UE 150 to observe. Each time between intervals is referred to as “burst period,” which may be longer than the duration of a burst.

[0073] In the example of 5G NR, each beam in a burst transmits information about the beam in what is referred to as a signal synchronization block (SSB). A network apparatus 210, which may be a gNodeB, or part thereof, transmits an SSB in each beam in a burst. In some examples, the network apparatus 210 may operate using one SSB (single beam operation) or using multiple SSBs (multi beam operation). In embodiments, the UE 150 may receive a SSB burst for each of its receive beams. In the example of four receive beams Rl, R2, R3, and R4, shown in FIG. 2, receiving the bursts for all four receive beams takes four intervals, as shown in FIG. 3. In some examples, the UE 150 may operate using a single beam (e.g., omnidirectional beam). The SSBs of an SS burst can be provided by one or more (co- or non co-located) TRP(s) (transmit-receivepoints). The duration between bursts is referred to as “burst periodicity.” In a 5G NR network, SSB bursts can each last 5ms, and burst periodicity can have a default duration of 20ms.

[0074] In the example of 5G NR, each SSB includes System Information (SI) in the form of Master Information Blocks (MIB) and a number of System Information Blocks (SIB). The SI is divided into Minimum SI and Other SI. Minimum SI includes basic information usable for accessing the network node and information for acquiring any other SI. Minimum SI includes the MIB, which contains cell-barred status information and physical layer information of the cell for receiving further system information (e.g., CORESET#0 configuration). MIB is periodically broadcast on a broadcast channel (BCH). Minimum SI also includes a System Information Block 1 (SIB1), which defines the scheduling of other system information blocks and contains information for accessing the network node. SIB1 may also be referred to as Remaining Minimum SI (RMSI) and is periodically broadcast on a downlink shared channel (DL-SCH).

[0075] Referring also to FIG. 2, in an example of the 5th generation new radio (5G NR) as defined by 3rd Generation Partnership Project (3 GPP), a unified transmission configuration indicator (TCI) framework is used for beam configurations and / or indications. For instance, the network apparatus 210 may configure the UE 150 with a set of TCI states. Each TCI state may indicate at least a certain beam direction or a group of beam directions, which may correspond to a certain reference signal. In an example, a TCI state can be a downlink (DL) TCI state for DL communication from the network apparatus 210 to the UE 150. In other examples, a TCI state can be an uplink (UL) TCI state for UL communication from the UE 150 to the network apparatus 210. In a further example, a TCI state can be a joint TCI state for UL and DL communications between the network apparatus 210 and the UE 150. The network apparatus 210 may “activate” the UE with at least a subset of the configured TCI states. As used herein, “activating” a TCI state means that a UE 150 may monitor signals transmitted by the network apparatus 210 corresponding to the TCI state, such as reference signals. In examples, activation of a TCI State may mean that the UE is configured monitor at least one reference signal associated with the activated TCI State, e.g., for time / frequency tracking and / or path loss measurement. In examples, activation may mean that a UE 150 is expected to track at least one reference signal corresponding to the activated TCI state. In some examples, the network apparatus 210 may activate one or more of the configured TCI states in the set and exclude one or more of the other configured TCI states in the set. Additionally, to communicate with the UE 150, the network apparatus 210 may select one of theactivated TCI states and “indicate” the selected TCI state to the UE 150. As used herein, “indicating” a TCI state means that a UE 150 may be configured to use the beam (identified by downlink reference signals) corresponding to the indicated TCI state to communicate with the network apparatus 210. In various examples, the UE 150 may be prepared to receive indication of at least one of the activated TCI state(s) and prepared to communicate with the network apparatus 210 using the indicated TCI state within specified time limits.

[0076] The examples of FIGS. 2 and 3 are merely illustrative. In embodiments, the number and direction of network node beams and the number and direction of UE beams may vary and may be different from those illustrated in FIGS. 2 and 3.

[0077] As explained above, a UE may travel from one area to another area, and thus cell switch or mobility procedures (e.g., layer 3 handover or LTM) can be important to support continued communication of the UE with the network. Further, a more efficient cell switch process, such as LTM, can be beneficial in avoiding or at least reducing disruption to the UE service as the UE moves from one cell coverage to another cell coverage.

[0078] FIG. 4 is a diagram of an example embodiment of an LTM scenario. As shown in FIG. 4, a UE 410 may be in communication with and served by a network apparatus 420 (e.g., a gNB, or a portion thereof) as indicated by the solid arrow. The UE 410 may be substantially similar to the UE 150 of FIG. 1. The network apparatus 420 may be substantially similar to the network apparatus 110 of FIG. 1. The network apparatus 420 that is actively or currently serving the UE 410 may be referred to as a serving cell. As the UE 410 travels towards an edge of a cell or area 402 served by (or under the coverage) of the network apparatus 420, a cell switch procedure may be performed to handover the UE 410 to a neighboring cell served by, e.g., another network apparatus 430, 440. In the illustrated example of FIG. 4, one neighboring cell is served by a network apparatus 430 and another neighboring cell is served by a network apparatus 440. The network apparatus 440 may cover (or serve) a cell or area 406 while the network apparatus 430 may cover an area 404. In some examples, the areas 402, 404, and 406 can partially overlap, as shown. In other examples, the areas 402, 404, and 406 can be non-overlapping. In the context of handover, the neighboring cells can be referred to as candidate cells. In the context of LTM, the neighboring cells can be referred to as LTM candidate cells.

[0079] The term Layer 1 / Layer 2 triggered mobility (LTM) may also be referred to as L1 / L2 triggered mobility, L1 / L2 inter-cell mobility, L1 / L2 handover, or lower layer (L1 / L2) mobility.These terms may be used interchangeably. A L1 / L2 signal, message, or command sent by a network node to trigger a cell switch at the UE is referred as a “cell switch command.” In LTM, the decision about a cell switch is based on LI measurements and is made in the MAC layer in a distributed unit (DU). A cell switch command includes a MAC control element (MAC CE). The cell that is the target of a cell switch command may be referred to herein as a target cell. Mechanisms for LTM will be discussed more fully below with reference to FIGS. 7—11.

[0080] According to an aspect of the present disclosure, the network apparatus 420 (the serving cell) may activate the UE 410 with TCI state(s) for candidate cell(s) and may optionally indicate an activated TCI state that may be used by the UE 410 in case of a cell switch. In this regard, the network apparatus 420 may transmit an indication of one or more candidate cells (e.g., the network apparatuses 430 and 440) and an activation of a respective list of one or more TCI states for each of the one or more candidate cell. Upon detection of degradation in operations or communications with the UE 410, the serving cell network apparatus 420 may transmit a cell switch command to the UE 410 via lower layer signaling (e.g., L1 / L2 signaling). The cell switch command may indicate a selected one of the one or more candidate cells as a target cell for the cell switch. In response to receiving the cell switch command, the UE 410 may switch to communicate with the target cell by applying at least one of the respective one or more activated TCI states.

[0081] The example of FIG. 4 is merely illustrative. In embodiments, the number of candidate cells and the number of activated TCI states (or beams) may vary and may be different from those illustrated in FIG. 4.

[0082] A procedure for a UE to establish communications with a target cell is referred to as random access procedure. Random access procedure may be used for initial access, small data transmissions in inactive and transition from RRC Inactive to RRC_Connected, as well as in beam failure recovery, connection re-establishment, handover, and cell addition, among other procedures which persons skilled in the art will recognize.

[0083] Two types of random access procedures include contention-based random access (CBRA) and contention-free random access (CFRA). FIG. 5 is a diagram of an example of a contention-based random access (CBRA) procedure. In the illustrated example, the signals include a random access preamble (MSG1) transmitted by the UE 550 towards the network node 510 (e.g., gNodeB, or part thereof), a random access response (MSG2) transmitted from the network node 510 towards the UE 550, a schedule transmission (MSG3) transmitted from the UE 550 towardsthe network node 510, and a contention resolution (MSG4) transmitted from the network node 510 towards the UE 550.

[0084] For MSG1, the UE 550 selects a usable random access preamble based on information elements in a signal synchronization block (SSB), such as the SSB described above in connection with FIG 3. The UE 550 sends the random access preamble (MSG1) towards the network node 510 using a specific time and frequency resource known as random access occasion (RO). The UE 550 also provides an identity, called random access radio network temporary identity (RA-RNTI), to the network so that the network can address it in the next step.

[0085] For MSG2, the network node 110 detects the preamble, calculates various quantities, and sends a physical uplink shared channel (PUSCH) uplink (UL) grant towards the UE 550. This is called the random access response (RAR), which is sent as MSG2 addressed to the UE 550 with the relevant RA-RNTI and indicates to the UE 550 where in frequency and when in time it can transmit MSG3 on the PUSCH.

[0086] For MSG3, in response to receiving the MSG2 from the network node 510, the UE 550 sends MSG3 using the UL grant provided in the RAR. Because the RAR provides a time resource allocation, the UE 550 sends MSG3 towards the network node 510 at a timing specified by the time resource allocation and is a scheduled transmission. This MSG3 may be called a radio resource control (RRC) connection request message.

[0087] For MSG4, the network node 510 may send MSG4 towards the UE 550 for contention resolution. Contention resolution may operate in the manner specified by 3GPP for 5GNR. After the random access procedure, assuming contention resolution is resolved favorably, the UE 550 becomes connected to the network node 510. After establishing a connection, various procedures would be handled by a gNB-CU in accordance with the CU-DU split. Other aspects of contentionbased random access (CBRA) will be understood by persons skilled in the art.

[0088] Another type of random access procedure is contention-free random access (CFRA) (not shown). In CFRA (not shown), the network node 510 transmits an allocated random access preamble towards the UE 550. The UE 550 receives the allocated random access preamble and sends the random access preamble to the network node 510 in a random access request as MSG1. Then, MSG2 and MSG3 are similar to those described in connection with CBRA. No conflict resolution is needed in CFRA based on use of an allocated random access preamble. Other aspects of contention-free random access (CFRA) will be understood by persons skilled in the art.

[0089] When a UE moves from the coverage area of one cell to another cell, a serving cell change is performed at some point. A conventional serving cell change may be triggered by Layer 3 (L3) measurements (RRC measurement report from the UE) and is done by downlink RRC signaling (i.e., an RRC reconfiguration message with synchronization for change of primary cell (PCell) and primary secondary cell (PSCell), as well as release and add for secondary cells (Scell) when applicable. All cases involve complete L2 (and LI) resets, possibly leading to longer latency, larger overhead, and longer interruption time than beam switch mobility. By utilizing L1 / L2 mobility enhancements to enable a serving cell change via L1 / L2 signaling, latency, overhead and interruption time may be reduced.

[0090] FIG. 6 is a diagram of an example embodiment 600 of signals and operations among a UE, a central unit (CU), a source distributed unit (DU), and a target DU, relating to LTM, according to one illustrated aspect of the disclosure. It is intended and shall be understood that other types of cell switch procedures (e.g., Layer 3 handover) are within the scope of the present disclosure. The following paragraphs will describe various signals and operations. It will be understood that a described signal may have associated operations and a described operation may have associated signals.

[0091] Referring now to FIG. 6, example signals and operations for LTM and a random access procedure are shown in relation to an inter-DU cell switch procedure. The inter-DU scenario is illustrative, and aspects of the present disclosure may be applied to intra-DU scenarios, as well. Where the source DU and target DU are supported by different CUs, the source DU may be supported by a source CU and the target DU may be supported by a target CU, which can communicate via an Xn interface. As mentioned above, the terms “transmit towards”, “receive from”, and “cooperate with” (and their variations), include communications that may or may not involve communications through one or more intermediate devices or nodes. It is intended that any description referring to a DU shall also be treated as though the description refers to a network node which supports at least one of DU functionality or a layer 2 protocol of a radio access network (RAN). It is intended that any description referring to a CU shall also be treated as though the description refers to a network node which supports at least one of CU functionality or a layer 3 protocol of a radio access network (RAN).

[0092] The following paragraphs describe various signals and operations. It will be understood that the described signals may have associated operations and the described operations may haveassociated signals. Accordingly, a described signal may also be an operation and a described operation may also be a signal.

[0093] Prior to operation 601, the UE has established a connection with a DU (i.e., source DU) that supports the serving cell which serves the UE and has established a (logical) connection with the CU that supports the DU.

[0094] At operation 601, the UE transmits an L3 measurement report towards the source DU, and the source DU receives the L3 measurement report from the UE. Persons skilled in the art will understand an L3 measurement report, which may include averaged measurement samples of reference signals for a serving cell, for example. An L3 measurement report may indicate, for example, that a UE is nearing an edge of a cell and, thus, handover procedures should be initiated. At operation 602, the source DU forwards the L3 measurement report by transmitting the L3 measurement report towards the CU (e.g., UL RRC transfer message), and the CU receives the L3 measurement report from the source DU. At operation 603, the CU performs a handover (HO) decision / target cell preparation decision for an LTM candidate and initiates the LTM candidate cell preparation (LTM candidate preparation), based on the L3 measurement report, about whether a handover should be prepared. For the illustrated embodiment, the CU decides that a handover should be prepared.

[0095] At operation 604, the CU transmits a UE context setup request towards the target DU to prepare the target DU for handover by setting up the UE context in the target DU. The target DU receives the UE context setup request from the CU and sets up the UE context. At operation 605, the target DU provides an acknowledgement by transmitting a UE context setup response towards the CU, and the CU receives the UE context setup response from the target DU. Although one target DU is illustrated, there may be more than one target DU if there are multiple candidate cells. The operations at 604 and 605 may be used for each target DU and for multiple candidate cells. The description below will refer to candidate cell(s) to indicate there may be one candidate cell or multiple candidate cells and, where appropriate, will refer to target DU(s) supporting the candidate cell(s). If a target DU and the source DU are supported by different CUs, the CUs may communicate using an Xn interface. For convenience, only one CU is illustrated (a CU supporting the source DU), but it is intended for the disclosed technology to apply to multi-CU situations, as well.

[0096] At operation 606, the CU transmits a UE context modification request towards thesource DU for modification of the UE context in the source DU, if needed, and for the provision of the target cell information (e.g., target cell RS configuration, activated or indicated TCI states, etc.). The source DU receives the UE context modification request from the CU, modifies the UE context (if needed), and receives the target cell information. At signal 607, the source DU provides an acknowledgment by transmitting a UE context modification response towards the CU, and the CU receives the UE context modification response from the source DU.

[0097] At operations 604-607, the CU, the target DU(s), and the source DU may coordinate with each other regarding timing advance acquisition and configuration for the candidate cell(s). Timing advance refers to information used by a UE to time its uplink transmissions towards a network node to arrive at the network node in alignment with a reception time window. This information may be referred to herein as a timing advance value or TA value, and the process of acquiring a timing advance value may be referred to herein as timing advance acquisition, TA acquisition, acquiring timing advance, or acquiring TA (or variations thereof). As described above herein, the term “acquire” (and its variations) includes acquiring in the first instance or reacquiring after the first instance. In embodiments, the source DU and the target DU(s) may coordinate (via the CU) on the method for the UE to acquire TA. In embodiments, a UE may acquire a separate TA value for each candidate cell.

[0098] In embodiments, TA may be acquired based on random access (RA) procedure (either CFRA or CBRA), such as, without limitation, a physical downlink control channel (PDCCH) ordered RA procedure, UE-triggered RA procedure, and / or a higher layer triggered RA procedure from a network node (other than a L3 handover command), among others. In embodiments, TA may be acquired based on non-RA procedure methods, such as, without limitation, sounding reference signal (SRS) based TA acquisition, receive timing difference based mechanisms (such as those in LTE), and / or UE-based TA measurement, among others. Such RA-based and non-RA- based methods for TA acquisition are within the scope of the present disclosure.

[0099] At operation 608, the CU creates an RRC reconfiguration message, which includes a measurement configuration for a LI cell change, a configuration of prepared cells, and a TA acquisition configuration and trigger for the candidate cells. In embodiments, the RRC reconfiguration message may include TA configuration if CU involvement is needed later (in the execution phase). The TA configuration may, for example, specify the method for a UE to acquire TA. In embodiments, the TA acquisition method can be configured / triggered based on L3measurements by the CU (in coordination with the source-DU).

[0100] At operation 609, the CU transmits the RRC reconfiguration message towards the source DU using a downlink (DL) RRC message transfer, and the source DU receives the RRC reconfiguration message from the CU. As mentioned above, the RRC reconfiguration message may include the TA configuration and activated or indicated TCI state information mentioned above as well as cell switch criteria. At operation 610, the source DU transmits the RRC reconfiguration message towards the UE to forward it to the UE, and the UE receives the RRC reconfiguration message from the source DU. The UE performs a reconfiguration based on the RRC reconfiguration message. At operation 611, the UE responds by transmitting a RRC reconfiguration complete message towards the source DU using an uplink (UL) RRC message transfer, and the source DU receives the RRC reconfiguration complete message from the UE. At operation 612, the source DU transmits the RRC reconfiguration complete message towards the CU to forward it to the CU, and the CU receives the RRC reconfiguration complete message from the source DU. In embodiments, the signals 609-612 may be described as part of a logical connection between the UE and the CU, such that the CU transmits the RRC message towards the UE, and the UE receives the RRC message from the CU.

[0101] In embodiments, the signals and operations 601-612 described above may be referred to as a preparation phase. After the preparation phase, in some embodiments, is an early synchronization (synch) phase.

[0102] Accordingly, at operation 613, the UE may perform downlink synchronization with candidate cells. At operation 614, the source DU transmits a TA acquisition command to the UE and the UE receives the TA acquisition command. The UE performs TA acquisition for the candidate cell(s) using the TA acquisition method specified in the RRC reconfiguration message of operation 608. As described above, TA may be acquired based on random access (RA) procedure (either CFRA or CBRA), such as, without limitation, a physical downlink control channel (PDCCH) ordered RA procedure, UE-triggered RA procedure, and / or a higher layer triggered RA procedure from a network node (other than a L3 handover command), among others. In embodiments, TA may be acquired based on non-RA procedure methods, such as, without limitation, sounding reference signal (SRS) based TA acquisition, receive timing difference based mechanisms (such as those in LTE), and / or UE-based TA measurement, among others. Such RA- based and non-RA-based methods for TA acquisition are within the scope of the present disclosure.After operation 615, the UE may have TA values for the candidate cell(s) before a cell switch is triggered if the TA acquisition procedure was successful. If the TA acquisition procedure was not successful, the UE would not have TA values for the candidate cell(s).

[0103] At operation 615, the UE transmits a random access (RACH) preamble message to the target DU so that the target DU can estimate the TA between the UE and the target DU. Upon receipt of the random access preamble message by the target DU, at operation 616, the target DU provides the TA to the UE (e.g., via the source DU or directly to the UE).

[0104] Operations 613-616 may be referred to as the early synch phase mentioned above. After the early synch phase, in some embodiments, is an execution phase.

[0105] In the execution phase, the UE, based on its configuration, provides periodic LI measurement reports. Persons skilled in the art will understand LI measurements. The LI measurements may measure signal power of a list of reference signals configured by the network. For example, LI measurements may measure signal power of reference signals corresponding to SSBs of activated TCI states. At operation 617, the UE periodically transmits the LI measurement reports towards the source DU, and the source DU receives the periodic LI measurement reports from the UE. In some cases, the reported measurements LI reports may be L3 measurements. The LI (or L3) measurements may include measurements on the configured LTM candidate target cell(s).

[0106] At operation 618, the source DU decides, based on the received LI measurement report, whether to trigger an LTM cell switch to a target cell of the set of candidate cells (i.e., candidate cells for the handover configured by the CU at operation 608).

[0107] At operation 618, the UE continues LI measurement reporting and periodically transmits LI measurement reports towards the source DU, and the source DU receives the periodic LI measurement reports from the UE. Based upon the determination, at operation 618a, the source DU transmits a MAC CE TCI activation for LTM command to the UE and the UE receives the MAC CE TCI activation command for LTM. The MAC CE TCI activation command for LTM may include one or more configuration identifiers (IDs) fields that are each associated with a respective candidate cell, and one or more TCI state IDs associated with the respective candidate cell. At operation 619, the source DU transmits a MAC CE trigger cell change message that includes the TA of the target cell and the TCI state indication to the UE and the UE receives the MAC CE trigger cell change message. Accordingly, at operation 620, the UE performs randomaccess procedure(s), which would be understood by persons skilled in the art. In various embodiments, at operation 620, the UE performs cell access based on the MAC CE TCI activation command and beam indication information referring to the one or more TCI states in the MAC CE TCI activation command. The beam indication information may also be provided prior to the provision of MAC CE triggering the cell change.

[0108] At operation 621, to initiate communication with the target DU, the UE transmits an RRC reconfiguration complete message towards the target DU using already configured uplink (UL) resources, and the target DU receives the RRC reconfiguration complete message from the UE. At operation 622, The target DU forwards the RRC reconfiguration complete message using a UL RRC message transfer to transmit the RRC reconfiguration complete message towards the CU, and the CU receives the RRC reconfiguration complete message from the target DU.

[0109] In embodiments, the signals and operations 617-622 may be referred to, collectively, as an execution phase. After the execution phase, in some example embodiments, is a completion phase.

[0110] At operation 623, the CU transmits a UE context release command / request towards the source DU to release the UE context from the source DU, and the source DU receives the UE context release command / request from the CU. The source DU releases the UE context in response to the UE context release command / request. At operation 624, the source DU transmits a UE context release complete message towards the CU, and the CU receives the UE context release complete message from the source DU. The CU may then perform a path switch to the target DU as the new DU supporting the serving cell.

[0111] In embodiments, the signals and operations 623-624 may be referred to, collectively, as a completion phase.

[0112] The signals and operations of FIG. 6 are merely illustrative, and variations are contemplated to be within the scope of the present disclosure. For example, the signals and operations may assume one TA value per physical cell ID (PCI). In embodiments, to cover multi- TRP (multi-transmit receipt point) scenarios, the UE may be configured and required to acquire multiple Tas for a PCI, such as, for example, different TA values for different sets of TCI-states. In embodiments, the signals and operations may include others not illustrated in FIG. 6. In embodiments, the signals and operations may not include every signal and operation illustrated in FIG. 6. In embodiments, the signals and operations may be implemented in a different order thanthat illustrated in FIG. 6. Such and other embodiments are contemplated to be within the scope of the present disclosure.

[0113] In order to support the operations described above in FIG. 6 for an LTM procedure, it may be desirable to provide information relating to the LTM candidate cells to the UE. In various embodiments, the UE will be provided an activation command for a set of TCI States (one or more) for a candidate cell that can be indicated by the network (that becomes the indicated TCI state for the LTM target cell). There may be one or more candidate cells configured for the UE.

[0114] Furthermore, in the LTM procedure described above in FIG. 6, the UE may have one or more prepared candidate cells and activate one or more TCI states specifically for a cell, the cell ID ( or a candidate cell configuration identifier or any other identifier that identifies the specific candidate cell configuration) may need to be indicated to the UE (e.g., in the MAC-CE), as well as the TCI state activation (e.g via TCI state ID) that applies for each candidate cell. Accordingly, the LTM configuration may include any number of prepared candidate cells and the UE may have multiple potential target cells, each having one or more potential target TCI states to be indicated for the use for the cell switch.

[0115] In order to minimize any HO related overhead and reduce points of potential interruption (such as messages being lost), a TCI state activation command that provides the ability to activate one or more TCI states for multiple candidate cells and signaling may be utilized to minimize the resource / signaling overhead for activation (and / or deactivation of the TCI states for one or more candidate cells).

[0116] In some embodiments, an LTM candidate cell may be referred to using a candidate cell ID. This candidate cell ID may be associated with a PCI value / physical cell identifier and the association is provided via RRC signaling. The candidate cell ID may be expressed with a smaller number of bits than the PCI in order to reduce the signaling overhead. As an example, the LTM candidate ID may be expressed with 3 bits, giving 8 different values for the set of candidate cells whereas the PCI may have ID space of 1008 values. Further, as mentioned above, the LTM candidate ID is associated with other configuration information (e.g., one or more RRC configured TCI states that can be activated for beam indication for LTM cell switch purposes).

[0117] The UE may be configured to interpret the MAC-CE command via RRC configuration, or other techniques known to persons of skill in the art. That is, the UE may beprovided with the information configured to interpret the MAC-CE command to know what information will be provided and in what format. In some examples, additional signaling to the UE may be provided that instruct the UE as to the interpretation technique for the MAC- CE. For example, additional fields could be added to the MAC-CE command to inform the UE of the format of the information. Accordingly, FIGS. 7-14 described below may provide information to the UE regarding LTM candidate configuration IDs and associated TCI state IDs. Additionally, similar reference numerals may indicate fields that include similar information, although not necessarily identical, among the several MAC-CEs depicted in FIGS. 7-14.

[0118] FIG. 7 is a diagram of an example TCI state activation MAC-CE 700 to support LTM 700, according to one illustrated aspect of the present disclosure. FIG. 7 includes a bitmap of cells as described below. As shown in FIG. 7, the MAC-CE includes a plurality of reserved fields 701 shown by R, a plurality of Pi fields 702 shown by Pl to P8 (e.g., i varies from 1 to 8), a plurality of LTM ID fields 703 shown by LTM ID1 to LTM ID8, , a plurality of D / U fields 704 shown by D / U, and TCI State ID fields 705 (shown as TCI state ID 1, . . ., TCI state ID N). In some cases, for clarity and to avoid clutter, only one of the plurality of fields may include a reference numeral label. In the example, there may be one to one mapping for Pi fields 702 and LTM ID fields 703. For example, the Pi corresponds (and provides associated information) to the ith LTM ID field.

[0119] The reserved field 701 is a reserved bit and may be set to 0 or another value. The reserved fields may be ignored / not decoded by the UE. The Pi field 702 indicates whether the one or more TCI codepoints for the ith LTM ID has multiple TCI states (i.e. separate TCI state) or a single TCI state (e.g. joint TCI state). If the Pi field 702 is set to 1, it may indicate that the at least one TCI codepoint for the ith LTM ID includes a DL TCI state and a UL TCI state. If the Pi field 702 is set to 0, it may indicate that the at least one TCI codepoint for the ith LTM ID includes a DL / joint TCI state or a UL TCI state. The codepoint to which a TCI state is mapped may be determined by its ordinal position among all the TCI state ID fields in the TCI state ID list field 705.

[0120] The TCI state ID in the TCI state list field 705 indicates the TCI state identified by TCIState Id as specified in the 3GPP TS 38.331 document. If a D / U field 704 is set to 1, 7- bits length TCI state ID, i.e., TCI-State Id as specified in 3GPP TS 38.331 document is used.If a D / U field 704 is set to 0, the most significant bit of TCI state ID may be considered as the reserved bit and the remainder 6 bits indicate the UL-TCI State-Id as specified in 3 GPP TS 38.331 document.

[0121] In this manner, the bit-position in the bitmap (LTM ID1...LTM ID8) may refer to a configuration ID of an LTM candidate cell. The LTM candidate ID refers to the configuration ID or any other logic ID used to represent a specific PCI that is associated with a LTM target cell. LTM ID range may also expressed in a format where the IDs start from 0 (e.g. 8 IDs, 0...7). It may also include current and other serving cells (e.g., primary and / or secondary cells). Accordingly, the configuration ID for a first candidate cell (e.g., LTM candidate ID 1) may be mapped to the LTM ID1 field, while a configuration ID for a second candidate cell (e.g., LTM candidate ID 2) may be mapped to the LTM ID2 field, and so on.. In another example, the candidate cell configuration IDs are mapped to the LTM ID fields in the ascending order of the candidate cell configuration IDs. Further, the TCI state ID 1 field may be associated with the first candidate cell and the TCI state ID 2 field may be associated with the second candidate cell. Although eight LTM ID fields are shown, it is to be understood that more or less fields may be included (e.g., different formats may comprise different number of fields for LTM ID). For LTM ID fields where the set bit is set (e.g. to 1), those LTM ID fields may indicate that there is TCI state information present for those candidate cells. For example, in a case where 2 candidate cells are identified, only the fields LTM ID1 and LTM ID2 are populated with their respective configuration IDs. For LTM ID fields where no bit is set (or set to 0), those LTM ID fields may indicate that there is no TCI state information present for those candidate cells. In other words, the number of LTM ID fields supported in the bitmap may be L (and e.g., L=8, 16,32) and the UE may be configured with up to L candidate cell configurations. In an example, different formats may be used for the different L values.

[0122] FIG. 8 is a diagram of example TCI state activation MAC-CE 800 to support LTM, according to another illustrated aspect of the present disclosure. As shown in FIG. 8, the LTM candidate ID fields 703, similar to those depicted in FIG. 7 above, may indicate the configuration IDs of candidate cells. In FIG. 8, it is indicated that there are 2 TCI states per codepoint options. That is, all the indicated candidate cells have 2 TCI states listed (in one codepoint).

[0123] Accordingly, as shown in FIG. 8, TCI state ID fields 705a may indicate a TCI state ID for a first codepoint (codepoint #1) for the first LTM ID (X), while TCI state ID fields 705b may indicate a TCI state ID for a first codepoint (codepoint #1) for the second LTM ID (Y). In some example embodiments, the first field 705a, corresponding to TCI state ID 1 may indicate a DL TCI state for LTM ID X, while the second field 705a, corresponding to TCI state ID 2 may indicate a UL TCI state for LTM ID X. Similarly, the first field 705b, corresponding to TCI state ID 3 may indicate a DL TCI state for LTM ID Y, while the second field 705b, corresponding to TCI state ID 4 may indicate a UL TCI state for LTM ID Y. As an example, for each of the (one or more) LTM IDs indicated by the bitmap, one or more TCI states are present. In the example of FIG. 8, for each LTM ID indicated by the bitmap (IDs X and Y) one TCI codepoint is present (thus comprising two TCI state IDs). FIG. 9 is a diagram of example TCI state activation MAC-CE 900 to support LTM, according to another illustrated aspect of the present disclosure. As shown in FIG. 9, the LTM candidate ID fields 703, similar to those depicted in FIG. 7 above, may indicate the configuration IDs of candidate cells. In FIG. 9, it is indicated that there are joint TCI states per codepoint options. That is, all the indicated candidate cells have 1 TCI state listed (in one codepoint). The number of TCI State codepoints per indicated LTM ID (e.g. for which the bit is set) may defined as part of the format. In an example it may be specified that in MAC-CE (or any message providing the TCI State activation) the indicated candidate cells (LTM ID) have 1 TCI state codepoint listed. In another example, it may be specified that in MAC-CE (or any message providing the TCI State activation) the indicated candidate cells (LTM ID) have 2 TCI state codepoints listed. Thus, the number of codepoints (K) may be specific to the format. Alternatively, the number of codepoints per indicated candidate cell may be configurable. TCI codepoint may comprise one or more TCI states e.g. one joint TCI for uplink (UL) and downlink (DL) or separate DL TCI and one UL TCI state. Whether the TCI state codepoint comprises of a joint TCI or joint TCIs or separate TCIs may be specific to the MAC CE format, or it may be configured. Alternatively, the number of TCI states in a codepoint in the MAC CE format may be determined based on the TCI State configuration wherein the configuration is provided by RRC (e.g., 1 joint TCI state list for UL and DL or 2 separate TCI state lists, one for DL, one for UL). Accordingly, as shown in FIG. 9, TCI state ID field 705a may indicate a TCI state ID for a first codepoint (codepoint #1) for the first LTM ID (X), while TCI state ID field 705bmay indicate a TCI state ID for a first codepoint (codepoint #1) for the second LTM ID (Y). In some example embodiments, the field 705a, corresponding to TCI state ID 1 may indicate a joint (i.e., UL / DL) TCI state for LTM ID X, while the field 705b, corresponding to TCI state ID 2 may indicate a joint TCI state for LTM ID Y.

[0124] In some embodiments, the activation message for LTM (e.g., the MAC-CE message) may be indicated by the logical channel ID (LCID) at the MAC layer. In some example embodiments, the UE can determine the proposed format or formats based on the LCID that identifies the specific MAC-CE.

[0125] FIG. 10 is a diagram of example TCI state activation MAC-CE 1000 to support LTM, according to another illustrated aspect of the present disclosure. As shown in FIG. 10, the LTM candidate ID fields 703, similar to those depicted in FIG. 7 above, may indicate the configuration IDs of candidate cells. In FIG. 10, the MAC-CE 1000 may indicate a configured (i.e., fixed) number of TCI state codepoints that are activated per indicated candidate cell, (e.g., K=l, 2, 3, 4 ... ). The value of K may be configured using RRC signaling.

[0126] In the example shown in FIG. 10, if K=l, for each cell indicated by the activation message, one TCI codepoint is listed. The TCI codepoint listed in the message configures the TCI states mapped to the codepoint are indicated as the activated TCI state codepoint. If, for example, K=2, for each cell indicated by the activation message, two TCI codepoints are listed (to be activated).

[0127] As shown in FIG. 10, the MAC-CE message further includes a set of bit fields for the cells for which the TCI State activations can be configured.. In some example embodiments, a candidate cell (associated with LTM ID) for which the TCI state is activated includes the bit field being set to a first value (e.g., 1). If no TCI states are configured for a particular candidate cell, the field is set to a second value (e.g., 0). Further, the TCI state activation codepoints may be listed in ascending order of the candidate cells that include the bit set to the first value, if more than (e.g., K=l) codepoints are listed per cell. In other words, for the indicated candidate cell (LTM ID) the K codepoints are listed first, then for the next candidate cell (LTM ID), if present, the next K codepoints are listed.

[0128] As shown in FIG. 10, all the codepoints for one cell are listed before the codepoints of a next cell. For the example where K=2, as shown in FIG. 10, the TCI state ID fields 705a correspond to LTM ID X and TCI state ID fields 705b correspond to LTM ID Y. Further, the TCIstate for codepoint #1 for LTM ID X is listed in the TCI state ID 1 field, while the TCI state for codepoint #2 for LTM ID X is listed in the TCI state ID 2 field. The TCI state for codepoint #1 for LTM ID Y is listed in the TCI state ID 3 field, while the TCI state for codepoint #2 for LTM ID Y is listed in the TCI state ID 4 field.

[0129] It may be noted that in some examples, K codepoints are configured to be listed in the activation command, but the network is able to activate TCI states for a cell less than K codepoints (i.e., codepoints comprising of different TCI State IDs). To activate less than K TCI states for a cell (i.e., codepoints comprising of different TCI State IDs) a TCI state ID (or at least one TCI state ID) may be repeated so that up to K codepoints are listed for a cell. The repeated ID may be the last listed TCI state ID for a cell. Such repetition may be used to keep the message format consistent. In an example, if in the activation message K codepoints are configured to be listed and network determines that less than K is to be activated, it may repeat the same TCI State ID value in each of the K TCI state ID fields that are listed. As a further example, if K=2, then listing TCI State ID #1 two times (e.g., in two octets), the UE may determine that TCI State ID#1 is activated. As a further example, if K=3, then listing TCI State ID #1 once, and TCI State ID #2 two times (e.g. in two octets), the UE may determine that TCI State ID#1 and TCI State ID#2 are activated. In an example, the TCI state ID fields that have repeated ID may be ignored by the UE for the cell (i.e., the repeated TCI state ID is applied once).

[0130] FIG. 11 is a diagram of example TCI state activation MAC-CE 1100 to support LTM, according to another illustrated aspect of the present disclosure. As shown in FIG. 11 , the LTM candidate ID fields 703, similar to those depicted in FIG. 7 above, may indicate the configuration IDs of candidate cells. Similar to the MAC-CE 1000 of FIG. 10, the MAC-CE 1100 may indicate the number K of TCI state codepoints that may be activated per candidate cell, with the value of K being configured using RRC signaling (by the network).

[0131] As shown in FIG. 11, the number K may be indicated in a field “K” 709 of the MAC- CE 1100. Accordingly, the field K 709 may be configured to include bit values corresponding to the number of TCI state codepoints that may be activated per candidate cell. For example, K=1 may correspond to a bit value of 00, K=2 may correspond to a bit value of 01, K=3 may correspond to a bit value of 10, and K=4 may correspond to a bit value of 11. It should be noted that the bit values described above are examples only and that any bit value may be assigned to correspond with any value for K. In a further example, a first bit value of thebitfield (709) may be configured (e.g., by RRC) to indicate a first value (e.g. K=l) and a second bit value of the bitfield (providing the value K) may map to a second value (e.g. K=3). Mapping may be configured using RRC signaling.

[0132] Accordingly, for the example case where K=2 shown in FIG. 11, all the codepoints for one cell are listed before the codepoints of a next cell. Accordingly, in FIG. 11, the TCI state ID fields 705a correspond to LTM ID X and TCI state ID fields 705b correspond to LTM ID Y. Further, the TCI state for codepoint #1 for LTM ID X is listed in the TCI state ID 1 field, while the TCI state for codepoint #2 for LTM ID X is listed in the TCI state ID 2 field. The TCI state for codepoint #1 for LTM ID Y is listed in the TCI state ID 3 field, while the TCI state for codepoint #2 for LTM ID Y is listed in the TCI state ID 4 field.

[0133] Further, it should be noted again that if K codepoints are configured to be listed in the activation command, but the network determines (or is able) to activate TCI states for a cell less than K codepoints, a TCI state ID may be repeated so that up to K is listed. The repeated ID may be the last listed TCI state ID for a cell.

[0134] FIG. 12 is a diagram of example TCI state activation MAC-CE 1200 to support LTM, according to another illustrated aspect of the present disclosure. As shown in FIG. 12, the LTM candidate ID fields 703, similar to those depicted in FIG. 7 above, may indicate the configuration IDs of candidate cells. FIG. 12 depicts an example MAC-CE 1200 where the number K of TCI codepoints per listed candidate cell may be dynamic and vary. In this example, the MAC-CE 1200 may provide an indication of whether a next listed TCI state in the TCI state ID field 705 is for a same candidate cell as the current TCI state ID field or a next candidate cell indicated in the next LTM ID field 703. In the example shown in FIG. 12, TCI state ID fields 1 / 2 705a correspond to respective codepoint #1 and #2 for LTM ID X (e.g., K=2). TCI state ID field 3 705b corresponds to respective codepoint #1 for LTM ID Y (e.g., K=l). TCI state ID fields 4 / 5 / 6 705c correspond to respective codepoints #1, #2 and #3 for LTM ID Z (e.g., K=3).

[0135] In an example embodiment, the TCI states may be configured for LTM purposes to be joint TCI states only, where there is only one TCI state per codepoint. A field (F) may be provided in the message (e.g., MAC-CE 1200), that is associated with a particular TCI state ID field, indicating whether a field that follows is for the same of different candidate cell listed in the activation command (e.g., MAC-CE 1200).

[0136] In some example embodiments, the F bit may be associated with a TCI state ID field.The F bit may be associated with a TCI state ID if they are on the same octet (8 bit sequence). In some examples, there may be a defined association between the F bit and a TCI state. The F bit may be set to either a first or second value (e.g., 1 or 0) for each TCI state listed in the MAC-CE 1200. In some examples, if the value is set to the first value (e.g. F= 1), it indicates that another TCI state ID field is listed for the same candidate cell. For example, the TCI state ID 1 octet includes F=l, and therefore indicates that another TCI state ID field follows (e.g., TCI State ID 2) for the same candidate cell, LTM ID X.

[0137] TCI state ID 2 is associated with a field having a second value of F (F=0), indicating that the next listed TCI state ID (in this example, TCI state ID 3) is for the next candidate cell, LTM ID Y. Since the value of F=0 in the octet associated with TCI state ID 3, this is an indication that the next listed TCI state ID (e.g., TCI state ID 4) is for the next candidate cell. The value of F for the octets associated with TCI state IDs 4 and 5 is equal to 1 in both cases, indicating that the next respective TCI state IDs (e.g., TCI state ID 5 and TCI state ID 6) are for the same candidate cell. The value of F for the octet associated with TCI state ID 6 is equal to 0, indicating that the next listed TCI state ID is for the next candidate cell. Accordingly, a variable number K may be enabled per candidate cell. If the F bit is set to value F=0 for the TCI State ID associated with the last (or highest value) indicated candidate cell ID (LTM ID), it indicates that no further TCI State fields are present.

[0138] In one example, if K codepoints are configured to be listed in the activation command, but the network is not able to activate TCI states for a cell less than K codepoints, it may signal in the message that no further TCI State IDs are present for an indicated cell. As an example, the message providing the activation command may comprise a field comprising of F fields, wherein setting the F bit to a specific value (e.g. first or second value) may indicate that no further TCI state IDs follow for the indicated cell (after the TCI State ID associated with the F field). This enables signaling of less than K codepoints per indicated cell although value K (K codepoints) is configured to be signaled in the message.

[0139] FIG. 13 is a diagram of example TCI state activation MAC-CE 1300 to support LTM, according to another illustrated aspect of the present disclosure. As shown in EIG. 13, the LTM candidate ID fields 703, similar to those depicted in EIG. 7 above, may indicate the configuration IDs of candidate cells. The MAC-CE 1300 of FIG. 13 may include another example indication of whether a next listed TCI state (codepoint) in the TCI state ID field 705 isfor a same candidate cell as the current TCI state ID field or a next candidate cell indicated in the next LTM ID field 703 (if any). In the example shown in FIG. 13, each codepoint may list two TCI states, one for uplink and one for downlink. In the example shown in FIG. 13, TCI state ID fields 1 / 2 705a correspond to codepoint #1 and TCI state ID fields 3 / 4 705a correspond to codepoint #2 for LTM ID X (e.g., K=2). TCI state ID fields 5 / 6 705b corresponds to respective codepoint #1 for LTM ID Y (e.g., K=l).

[0140] In the example shown in FIG. 13, field F in the message (e.g., MAC-CE 1300) that is associated with a particular TCI state (e.g., is on the same octet or is some other way associated) may indicate whether a TCI state ID field that follows is for the same candidate cell or different candidate cell listed in the activation command (e.g., MAC-CE 1300). For example, as shown in FIG. 13, the F field is associated with either of the two TCI states per codepoint, but for example purposes is shown as being associated with the latter one. The F bit indicates whether the next two TCI states / codepoint is for the same candidate cell or the next candidate cell listed in the activation message. If the TCI state IDs (or codepoints) for the candidate cells are listed in the activation message and no further codepoints / TCI states are listed for any of the cells (e.g., the last indicated LTM ID in the message), the F field may be set to value F=0. The UE determines that no further TCI states are present in the activation message.

[0141] As per the example embodiment shown in FIG. 13, a value of F=1 is shown associated with the TCI state ID field for TCI state ID 2, which indicates that the next two TCI state ID fields include TCI state information for the same candidate cell as TCI fields 1 and 2. The value of F=0 is shown associated with the TCI state ID field for TCI state ID 4, which indicates that the next two TCI state ID fields (e.g., TCI stated IDs 5 and 6) include TCI state information for the next candidate cell.

[0142] FIG. 14 is a diagram of example TCI state activation MAC-CE 1400 to support LTM, according to another illustrated aspect of the present disclosure. As shown in FIG. 141, the LTM candidate ID fields 703, similar to those depicted in FIG. 7 above, may indicate the configuration IDs of candidate cells. The MAC-CE 1400 of FIG. 14 may include a DL bandwith part (BWP) ID field 706 and a UL BWP ID field 707.

[0143] The DL BWP field 706 may indicate a DL BWP for which the MAC-CE 1400 applies as the codepoint of the DCI bandwidth part indicator field as specified in, for example, the 3 GPP TS 38.212 document. The UL BWP field 707 may indicate a UL BWP for whichthe MAC-CE 1400 applies as the codepoint of the DCI bandwidth part indicator field as specified in, for example, the 3 GPP TS 38.212 document. It should be noted that one or both of the DL BWP or UL BWP fields 706 / 707 may be included in the MAC-CE 1400 message.

[0144] Accordingly, if the MAC-CE 1400 message includes at least one of the DL or UL BWP fields 706 / 707, the same BWP ID may be assumed for all the cells for which the activation command provides as candidate cells (e.g., in the LTM ID fields 703).

[0145] Referring now to FIG. 15, there is shown a block diagram of example components of a UE or a network apparatus. The apparatus includes an electronic storage 1510, a processor 1520, a memory 1550, and a network interface 1540. The various components may be communicatively coupled with each other. The processor 1520 may be and may include any type of processor, such as a single-core central processing unit (CPU), a multi-core CPU, a microprocessor, a digital signal processor (DSP), a System-on-Chip (SoC), or any other type of processor. The memory 1550 may be a volatile type of memory, e.g., RAM, or a non-volatile type of memory, e.g., NAND flash memory. The memory 1550 includes processor-readable instructions that are executable by the processor 1520 to cause the apparatus to perform various operations, including those mentioned herein, such as the operations of FIG. 6, for example.

[0146] The electronic storage 1510 may be and include any type of electronic storage used for storing data, such as hard disk drive, solid state drive, and / or optical disc, among other types of electronic storage. The electronic storage 1510 stores processor-readable instructions for causing the apparatus to perform its operations and stores data associated with such operations, such as storing data relating to 5G NR standards, among other data. The network interface 1540 may implement wireless networking technologies such as 5G NR and / or other wireless networking technologies.

[0147] The components shown in FIG. 15 are merely examples, and persons skilled in the art will understand that an apparatus includes other components not illustrated and may include multiples of any of the illustrated components. Such and other embodiments are contemplated to be within the scope of the present disclosure.

[0148] Further embodiments of the present disclosure include the following examples.

[0149] Example 1.1. A user equipment, comprising: means for receiving a configuration for one or more of candidate cells of a plurality of candidate cells, with respective candidate cell configuration identifiers; andmeans for receiving a first message, wherein the first message includes a plurality of candidate cell configuration identifier fields, each candidate cell configuration identifier field associated with one of the plurality of candidate cells, wherein the first message further includes at least one transmission configuration indicator, TCI state identifier, per indicated candidate cell configuration identifier of the plurality of candidate cell configuration identifier fields.

[0150] Example 1.2. The user equipment of example 1.1, wherein the TCI state identifiers include a TCI state for one or more codepoints.

[0151] Example 1.3. The user equipment of example 1.2, wherein a first TCI state identifier for a first codepoint indicates the TCI state for uplink communication and a second TCI state identifier for a second codepoint indicates the TCI state for downlink communication.

[0152] Example 1.4. The user equipment of example 1.3, wherein the first TCI state and the second TCI state are the same.

[0153] Example 1.5. The user equipment as in any of example 1.1-1.4, wherein the first message further includes an indication of a number of TCI state codepoints activated for each of the indicated one or more candidate cell identifiers.

[0154] Example 1.6. The user equipment of example 1.5, wherein the number of TCI state codepoints activated for each of the one or more candidate cells is a configured number.

[0155] Example 1.7. The user equipment as in any of example 1.5-1.6, wherein the first message further includes a field indicating the number of TCI state codepoints activated for each of the indicated one or more candidate cell identifiers.

[0156] Example 1.8. The user equipment of example 1.5, wherein for a first candidate cell identifier of the one or more candidate cell identifiers include a first number of TCI state codepoints activated and a second candidate cell identifiers of the one or more candidate cell identifiers include a second number of TCI state codepoints activated.

[0157] Example 1.9. The user equipment of example 1.8, wherein the first message further includes a first indicator to indicate the number of first TCI state codepoints activated for the first candidate cell of the one or more candidate cells and a second indicator to indicate the number of second TCI state codepoints activated for the secondcandidate cell of the one or more candidate cells.

[0158] Example 1.10. The user equipment of example 1.5, wherein the first message includes a candidate cell-TCI state indication that a next TCI state identifier is a TCI state of a same candidate cell or a different candidate cell.

[0159] Example 1.11. The user equipment of example 1.10, wherein the candidate cell-TCI state indication includes a first value upon the next TCI state identifier being a TCI state of a same candidate cell and wherein the candidate cell-TCI state indication includes a second value upon the next TCI state identifier being a TCI state of a next candidate cell.

[0160] Example 1.12. The user equipment of example 1.1, wherein the first message further includes a bandwidth part (BWP) ID, wherein a same BWP ID is indicated for each of the one or more candidate cells.

[0161] Example 1.13. The user equipment of example 1.12, wherein the BWP ID is one or more of an uplink (UL) BWP ID or a downlink (DL) BWP ID.

[0162] Example 2.1. An apparatus, comprising: means for transmitting to a user equipment, a configuration for one or more candidate cells of a plurality of candidate cells, with respective candidate cell identifiers; and means for transmitting a first message to the user equipment, wherein the first message includes a plurality of candidate cell configuration identifier fields, each candidate cell configuration identifier field associated with one of the plurality of candidate cells, wherein the first message further includes at least one transmission configuration indicator, TCI state identifier, per indicated candidate cell configuration identifier of the plurality of candidate cell configuration identifier fields.

[0163] Example 2.2. The apparatus of example 2.1, wherein the TCI state identifiers include a TCI state for one or more codepoints.

[0164] Example 2.3. The user equipment of example 2.2 wherein a first TCI state identifier for a first codepoint indicates the TCI state for uplink communication and a second TCI state identifier for a second codepoint indicates the TCI state for downlink communication.

[0165] Example 2.4. The apparatus of example 2.3, wherein the first TCI state andthe second TCI state are the same.

[0166] Example 2.5. The apparatus as in any of examples 2.2-2.4, wherein the first message further includes an indication of a number of TCI state codepoints activated for each of the one or more candidate cells.

[0167] Example 2.6. The apparatus of example 2.5, wherein the number of TCI state codepoints activated for each of the one or more candidate cells is a configured number.

[0168] Example 2.7. The apparatus as in any of examples 2.5-2.6, wherein the first message further includes a field indicating the number of TCI state codepoints activated for each of the one or more candidate cells.

[0169] Example 2.8. The apparatus of example 2.5, wherein a first candidate cell of the one or more candidate cells includes a first number of TCI state codepoints activated and a second candidate cell of the one or more candidate cells includes a second number of TCI state codepoints activated.

[0170] Example 2.9. The apparatus of example 2.8, wherein the first message further includes a first indicator to indicate the number of first TCI state codepoints activated for the first candidate cell of the one or more candidate cells and a second indicator to indicate the number of second TCI state codepoints activated for the second candidate cell of the one or more candidate cells.

[0171] Example 2.10. The apparatus of example 2.5, wherein the first message includes a candidate cell-TCI state indication that a next TCI state identifier is a TCI state of a same candidate cell or a different candidate cell.

[0172] Example 2.11. The apparatus of example 2.10, wherein the candidate cell- TCI state indication includes a first value upon the next TCI state identifier being a TCI state of a same candidate cell and wherein the candidate cell-TCI state indication includes a second value upon the next TCI state identifier being a TCI state of a next candidate cell.

[0173] Example 2.12. The apparatus of example 2.1, wherein the first message further includes a bandwidth part (BWP) ID, wherein a same BWP ID is indicated for each of the one or more candidate cells.

[0174] Example 2.13. The apparatus of example 2.12, wherein the BWP ID is one or more of an uplink (UL) BWP ID or a downlink (DL) BWP ID.

[0175] The embodiments and aspects disclosed herein are examples of the present disclosure and may be embodied in various forms. For instance, although certain embodiments herein are described as separate embodiments, each of the embodiments herein may be combined with one or more of the other embodiments herein. Specific structural and functional details disclosed herein are not to be interpreted as limiting, but as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. Like reference numerals may refer to similar or identical elements throughout the description of the figures.

[0176] For example, the TCI state activation message for one more candidate cells is signaled by the network (e.g. as serving cell) to the UE as a MAC-GE message. However, it should be noted that the signaling may be provided in another message.

[0177] In some examples, a TCI codepoint may refer to a joint TCI state index (e.g., the same TCI is used DL and UL) in which case it refers to one TCI state. In some examples, a TCI codepoint may refer to separate TCI State indices for DL and UL in which case it refers to two TCI states.

[0178] In an example embodiment, a cell referred to above may be an LTM candidate cell and / or a serving cell. An LTM candidate cell may be a serving cell of the UE. In some examples, the activation message that refers to TCI states may refer to one or more TCI state lists associated / configured for one or more cells (e.g., candidate cells).

[0179] The phrases “in an aspect,” “in aspects,” “in various aspects,” “in some aspects,” or “in other aspects” may each refer to one or more of the same or different aspects in accordance with this present disclosure. The phrase “a plurality of’ may refer to two or more.

[0180] The phrases “in an embodiment,” “in embodiments,” “in various embodiments,” “in some embodiments,” or “in other embodiments” may each refer to one or more of the same or different embodiments in accordance with the present disclosure. A phrase in the form “A or B” means “(A), (B), or (A and B).” A phrase in the form “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) ”

[0181] Any of the herein described methods, programs, algorithms or codes may be converted to, or expressed in, a programming language or computer program. The terms “programming language” and “computer program,” as used herein, each include any language used to specify instructions to a computer, and include (but is not limited to) the following languages and their derivatives: Assembler, Basic, Batch files, BCPL, C, C+, C++, Delphi, Fortran, Java, JavaScript,machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, Visual Basic, metalanguages which themselves specify programs, and all first, second, third, fourth, fifth, or further generation computer languages. Also included are database and other data schemas, and any other meta-languages. No distinction is made between languages which are interpreted, compiled, or use both compiled and interpreted approaches. No distinction is made between compiled and source versions of a program. Thus, reference to a program, where the programming language could exist in more than one state (such as source, compiled, object, or linked) is a reference to any and all such states. Reference to a program may encompass the actual instructions and / or the intent of those instructions.

[0182] While aspects of the present disclosure have been shown in the drawings, it is not intended that the present disclosure be limited thereto, as it is intended that the present disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular aspects. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

WHAT IS CLAIMED IS:

1. A method, comprising: receiving, by a user equipment, a configuration for one or more of candidate cells of a plurality of candidate cells, with respective candidate cell configuration identifiers; and receiving, by the user equipment, a first message, wherein the first message includes a plurality of candidate cell configuration identifier fields, each candidate cell configuration identifier field associated with one of the plurality of candidate cells, wherein the first message further includes at least one transmission configuration indicator, TCI state identifier, per indicated candidate cell configuration identifier of the plurality of candidate cell configuration identifier fields.

2. The method of claim 1, wherein the TCI state identifiers include a TCI state for one or more codepoints.

3. The method of claim 2, wherein a first TCI state identifier for a first codepoint indicates the TCI state for uplink communication and a second TCI state identifier for a second codepoint indicates the TCI state for downlink communication.

4. The method of claim 3, wherein the first TCI state and the second TCI state are the same.

5. The method as in any of claims 1-4, wherein the first message further comprises an indication of a number of TCI state codepoints activated for each of the indicated one or more candidate cell identifiers.

6. The method of claim 5, wherein the number of TCI state codepoints activated for each of the one or more candidate cells is a configured number.

7. The method as in any of claims 5-6, wherein the first message further comprises a field indicating the number of TCI state codepoints activated for each of the indicated one or more candidate cell identifiers.

8. The method of claim 5, wherein for a first candidate cell identifier of the one or more candidate cell identifiers include a first number of TCI state codepoints activated and a second candidate cell identifiers of the one or more candidate cell identifiers include a second number of TCI state codepoints activated.

9. The method of claim 8, wherein the first message further comprises a first indicator to indicate the number of first TCI state codepoints activated for the first candidate cell of the one or more candidate cells and a second indicator to indicate the number of second TCI state codepoints activated for the second candidate cell of the one or more candidate cells.

10. The method of claim 5, wherein the first message includes a candidate cell-TCI state indication that a next TCI state identifier is a TCI state of a same candidate cell or a different candidate cell.

11. The method of claim 10, wherein the candidate cell-TCI state indication includes a first value upon the next TCI state identifier being a TCI state of a same candidate cell and wherein the candidate cell-TCI state indication includes a second value upon the next TCI state identifier being a TCI state of a next candidate cell.

12. The method of claim 1, wherein the first message further comprises a bandwidth part (BWP) ID, wherein a same BWP ID is indicated for each of the one or more candidate cells.

13. The method of claim 12, wherein the BWP ID is one or more of an uplink (UL) BWP ID or a downlink (DL) BWP ID.

14. A method, comprising:transmitting, by an apparatus, to a user equipment, a configuration for one or more candidate cells of a plurality of candidate cells, with respective candidate cell identifiers; and transmitting, by the apparatus, a first message to the user equipment, wherein the first message includes a plurality of candidate cell configuration identifier fields, each candidate cell configuration identifier field associated with one of the plurality of candidate cells, wherein the first message further includes at least one transmission configuration indicator, TCI state identifier, per indicated candidate cell configuration identifier of the plurality of candidate cell configuration identifier fields.

15. The method of claim 14, wherein the TCI state identifiers include a TCI state for one or more codepoints.

16. The method of claim 15, wherein a first TCI state identifier for a first codepoint indicates the TCI state for uplink communication and a second TCI state identifier for a second codepoint indicates the TCI state for downlink communication.

17. The method of claim 16, wherein the first TCI state and the second TCI state are the same.

18. The method as in any of claims 14-17, wherein the first message further comprises an indication of a number of TCI state codepoints activated for each of the one or more candidate cells.

19. The method of claim 18, wherein the number of TCI state codepoints activated for each of the one or more candidate cells is a configured number.

20. The method as in any of claims 18-19, wherein the first message further comprises a field indicating the number of TCI state codepoints activated for each of the one or more candidate cells.

21. The method of claim 18, wherein a first candidate cell of the one or more candidate cells includes a first number of TCI state codepoints activated and a second candidate cell of the one or more candidate cells includes a second number of TCI state codepoints activated.

22. The method of claim 21, wherein the first message further comprises a first indicator to indicate the number of first TCI state codepoints activated for the first candidate cell of the one or more candidate cells and a second indicator to indicate the number of second TCI state codepoints activated for the second candidate cell of the one or more candidate cells.

23. The method of claim 18, wherein the first message includes a candidate cell-TCI state indication that a next TCI state identifier is a TCI state of a same candidate cell or a different candidate cell.

24. The method of claim 23, wherein the candidate cell-TCI state indication includes a first value upon the next TCI state identifier being a TCI state of a same candidate cell and wherein the candidate cell-TCI state indication includes a second value upon the next TCI state identifier being a TCI state of a next candidate cell.

25. The method of claim 14, wherein the first message further comprises a bandwidth part (BWP) ID, wherein a same BWP ID is indicated for each of the one or more candidate cells.

26. The method of claim 25, wherein the BWP ID is one or more of an uplink (UL) BWP ID or a downlink (DL) BWP ID.

27. A user equipment, comprising: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, cause the apparatus at least to perform at least the following: receiving a configuration for one or more of candidate cells of a plurality of candidate cells, with respective candidate cell configuration identifiers; andreceiving a first message, wherein the first message includes a plurality of candidate cell configuration identifier fields, each candidate cell configuration identifier field associated with one of the plurality of candidate cells, wherein the first message further includes at least one transmission configuration indicator, TCI state identifier, per indicated candidate cell configuration identifier of the plurality of candidate cell configuration identifier fields.

28. The user equipment of claim 27, wherein the TCI state identifiers include a TCI state for one or more codepoints.

29. The user equipment of claim 28, wherein a first TCI state identifier for a first codepoint indicates the TCI state for uplink communication and a second TCI state identifier for a second codepoint indicates the TCI state for downlink communication.

30. The user equipment of claim 29, wherein the first TCI state and the second TCI state are the same.

31. The user equipment as in any of claims 1-4, wherein the first message further comprises an indication of a number of TCI state codepoints activated for each of the indicated one or more candidate cell identifiers.

32. The user equipment of claim 31, wherein the number of TCI state codepoints activated for each of the one or more candidate cells is a configured number.

33. The user equipment as in any of claims 31-32, wherein the first message further comprises a field indicating the number of TCI state codepoints activated for each of the indicated one or more candidate cell identifiers.

34. The user equipment of claim 31, wherein for a first candidate cell identifier of the one or more candidate cell identifiers include a first number of TCI state codepoints activated and a second candidate cell identifiers of the one or more candidate cell identifiers include a second number of TCI state codepoints activated.

35. The user equipment of claim 34, wherein the first message further comprises a first indicator to indicate the number of first TCI state codepoints activated for the first candidate cell of the one or more candidate cells and a second indicator to indicate the number of second TCI state codepoints activated for the second candidate cell of the one or more candidate cells.

36. The user equipment of claim 31, wherein the first message includes a candidate cell-TCI state indication that a next TCI state identifier is a TCI state of a same candidate cell or a different candidate cell.

37. The user equipment of claim 36, wherein the candidate cell-TCI state indication includes a first value upon the next TCI state identifier being a TCI state of a same candidate cell and wherein the candidate cell-TCI state indication includes a second value upon the next TCI state identifier being a TCI state of a next candidate cell.

38. The user equipment of claim 27, wherein the first message further comprises a bandwidth part (BWP) ID, wherein a same BWP ID is indicated for each of the one or more candidate cells.

39. The user equipment of claim 38, wherein the BWP ID is one or more of an uplink (UL) BWP ID or a downlink (DL) BWP ID.

40. A processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, causes the apparatus at least to perform a method as in any one of claims 1-13.

41. An apparatus, comprising: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, cause the apparatus at least to perform at least the following:transmitting, by an apparatus, to a user equipment, a configuration for one or more candidate cells of a plurality of candidate cells, with respective candidate cell identifiers; and transmitting, by the apparatus, a first message to the user equipment, wherein the first message includes a plurality of candidate cell configuration identifier fields, each candidate cell configuration identifier field associated with one of the plurality of candidate cells, wherein the first message further includes at least one transmission configuration indicator, TCI state identifier, per indicated candidate cell configuration identifier of the plurality of candidate cell configuration identifier fields.

42. The apparatus of claim 41, wherein the TCI state identifiers include a TCI state for one or more codepoints.

43. The apparatus of claim 42, wherein a first TCI state identifier for a first codepoint indicates the TCI state for uplink communication and a second TCI state identifier for a second codepoint indicates the TCI state for downlink communication.

44. The apparatus of claim 43, wherein the first TCI state and the second TCI state are the same.

45. The apparatus as in any of claims 41-44, wherein the first message further comprises an indication of a number of TCI state codepoints activated for each of the one or more candidate cells.

46. The apparatus of claim 45, wherein the number of TCI state codepoints activated for each of the one or more candidate cells is a configured number.

47. The apparatus as in any of claims 45-46, wherein the first message further comprises a field indicating the number of TCI state codepoints activated for each of the one or more candidate cells.

48. The apparatus of claim 45, wherein a first candidate cell of the one or more candidate cells includes a first number of TCI state codepoints activated and a second candidate cell of the one or more candidate cells includes a second number of TCI state codepoints activated.

49. The apparatus of claim 48, wherein the first message further comprises a first indicator to indicate the number of first TCI state codepoints activated for the first candidate cell of the one or more candidate cells and a second indicator to indicate the number of second TCI state codepoints activated for the second candidate cell of the one or more candidate cells.

50. The apparatus of claim 45, wherein the first message includes a candidate cell-TCI state indication that a next TCI state identifier is a TCI state of a same candidate cell or a different candidate cell.

51. The apparatus of claim 50, wherein the candidate cell-TCI state indication includes a first value upon the next TCI state identifier being a TCI state of a same candidate cell and wherein the candidate cell-TCI state indication includes a second value upon the next TCI state identifier being a TCI state of a next candidate cell.

52. The apparatus of claim 41, wherein the first message further comprises a bandwidth part (BWP) ID, wherein a same BWP ID is indicated for each of the one or more candidate cells.

53. The apparatus of claim 52, wherein the BWP ID is one or more of an uplink (UL) BWP ID or a downlink (DL) BWP ID.

54. A processor-readable medium storing instructions which, when executed by at least one processor of an apparatus, causes the apparatus at least to perform a method as in any one of claims 14-26.

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