Transmission configuration indicator (TCI) state for cell handover

Abstract

A user equipment device includes processor (s) and at least one memory. The memory stores instructions that, when executed by the processor (s), cause the user equipment device to at least: receive one or more activated transmission configuration indicator (TCI) states for a candidate cell from a serving cell; receiving a cell switching command for switching from the serving cell to the candidate cell from the serving cell, wherein the candidate cell is a target cell of the cell switching command; in response to the cell switching command, a random access process with the target cell is executed, and after the random access process is successfully completed, the target cell becomes a new service cell; and maintaining at least one of the one or more activated TCI states as one or more activated TCI states of the new serving cell after the random access procedure with the target cell is successfully completed.

Description

Technical Field

[0001] Various example embodiments generally relate to wireless networking, and more specifically, to the Transmission Configuration Indicator (TCI) state of mobility in wireless networking. Background Technology

[0002] Wireless networking offers significant advantages to user mobility. The ability to maintain connectivity while on the move not only benefits the user but also contributes to greater efficiency and productivity for society as a whole. As user expectations for connection reliability, data speed, and device battery life increase, wireless networking technologies must keep pace. Therefore, there is a sustained interest in improving wireless networking technologies. For this purpose, cellular standards have developed cell handover at various protocol layers: traditional Layer 3 handover has existed for several generations. On top of this, conditional handover has been introduced to improve handover reliability. Recent developments have considered lower-layer handover known as Layer 1 / Layer 2 triggered mobility (LTM). Summary of the Invention

[0003] According to various aspects of this disclosure, a user equipment apparatus includes one or more processors and at least one memory. The at least one memory stores instructions that, when executed by the one or more processors, cause at least [a certain condition] in the user equipment apparatus.

[0004] In one aspect of this disclosure, a user equipment apparatus includes one or more processors and at least one memory storing instructions. When executed by the one or more processors, the instructions cause the user equipment apparatus to at least: receive from a serving cell one or more activated Transport Configuration Indicator (TCI) states for a candidate cell; receive from the serving cell a cell handover command to switch from the serving cell to the candidate cell, wherein the candidate cell is the target cell of the cell handover command; in response to the cell handover command, perform a random access procedure with the target cell, wherein after the random access procedure is successfully completed, the target cell becomes the new serving cell; and after the random access procedure with the target cell is successfully completed, maintain at least one of the one or more activated TCI states as one or more activated TCI states of the new serving cell.

[0005] In one aspect of the user equipment apparatus, the instruction, when executed by the one or more processors, may further cause the user equipment apparatus to at least: determine, in response to the cell handover command, that a timing advance (TA) value has not yet been provided for the target cell in the cell handover command; and receive the TA value of the target cell via a random access procedure.

[0006] In one aspect of the user equipment apparatus, the instruction, when executed by the one or more processors, may further cause the user equipment apparatus to at least: receive an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and maintain the indication of the one TCI state as the indicated TCI state of the new serving cell after the random access procedure with the target cell is successfully completed.

[0007] In one aspect of the user equipment device, one or more activated TCI states of the new serving cell may include only the indicated TCI state of the new serving cell, and among the one or more activated TCI states, TCI states other than the indicated TCI state are deactivated.

[0008] In one aspect of the user equipment apparatus, the instruction, when executed by the one or more processors, may further cause the user equipment apparatus to at least: receive an indication of one of the one or more activated TCI states in the cell handover command before performing a random access procedure with the target cell; and after the successful completion of the random access procedure with the target cell, determine, based on the cell handover command, one of the following: maintaining an indication to maintain at least one of the one or more activated TCI states but not the one TCI state; maintaining an indication to maintain the one TCI state but not the one or more activated TCI states; or maintaining at least one of the one or more activated TCI states and maintaining the indication to maintain the one TCI state.

[0009] In one aspect of the user equipment apparatus, the instruction, when executed by the one or more processors, may further cause the user equipment apparatus to at least: receive an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and determine, after the random access procedure with the target cell is successfully completed, not to maintain the indication of the one TCI state as the indicated TCI state of the new serving cell.

[0010] In one aspect of the user equipment apparatus, the determination of an indication not to maintain the TCI state may be based on: a CORESET index value associated with a common search space (CSS) of at least one type of physical downlink control channel (PDCCH), and a configuration having at least one field value corresponding to the indication not to apply the TCI state. When executed by the one or more processors, the instruction may further cause the user equipment apparatus to at least: based on the determination, apply a quasi-co-located (QCL) source to monitor at least one CSS on at least one CORESET based on a reference signal selected for the random access procedure.

[0011] In one aspect of the user equipment apparatus, when performing a random access procedure with the target cell, the instruction, when executed by the one or more processors, may cause the user equipment apparatus to at least: select one of the SSBs or QCL source SSBs corresponding to an indicated TCI state if the corresponding Signal Synchronization Block (SSB) or Quasi-Co-located (QCL) source SSB has a reference signal received power (RSRP) higher than a threshold.

[0012] In one aspect of the user equipment apparatus, the instruction, when executed by the one or more processors, may further cause the user equipment apparatus to at least: determine that a timing advance (TA) value was acquired prior to the cell handover command; and that the cell handover command does not include the TA value; and, based on the determination, decide to trigger a random access procedure.

[0013] In one aspect of the user equipment apparatus, the instruction, when executed by the one or more processors, may further cause the user equipment apparatus to at least: in response to the cell handover command, determine that a timing advance (TA) value for the target cell has been acquired, and determine one of the following: uplink resources have been configured for the target cell, or the scheduling of the uplink resources is to be monitored; based on the determination, transmit uplink messages to the target cell using the uplink resources; and determine that a random access procedure is triggered before the uplink messages are successfully transmitted to the target cell, wherein the random access procedure is executed in response to the triggering of the random access procedure.

[0014] In one aspect of the user equipment apparatus, the instruction, when executed by the one or more processors, may further cause the user equipment apparatus to at least: receive an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and maintain the indication of the one TCI state as the indicated TCI state of the new serving cell after the random access procedure with the target cell is successfully completed.

[0015] In one aspect of the user equipment apparatus, the instruction, when executed by the one or more processors, may further cause the user equipment apparatus to at least: receive an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and determine, after the random access procedure with the target cell is successfully completed, not to maintain the indication of the one TCI state as the indicated TCI state of the new serving cell.

[0016] In one aspect of the user equipment apparatus, the instructions, when executed by the one or more processors, may further cause the user equipment apparatus to at least: receive, for each of a plurality of candidate cells, one or more corresponding activated transport configuration indicator (TCI) states of the respective candidate cell from the serving cell, wherein the plurality of candidate cells includes the candidate cells.

[0017] In one aspect of the user equipment device, the cell handover command may be a Layer 1 / Layer 2 triggered mobility (LTM) cell handover command.

[0018] According to various aspects of this disclosure, a processor-implemented method includes: receiving from a serving cell one or more activated Transport Configuration Indicator (TCI) states for a candidate cell; receiving from the serving cell a cell handover command for switching from the serving cell to the candidate cell, wherein the candidate cell is the target cell of the cell handover command; in response to the cell handover command, performing a random access procedure with the target cell, wherein after the random access procedure is successfully completed, the target cell becomes the new serving cell; and after the random access procedure with the target cell is successfully completed, maintaining the one or more activated TCI states as the activated TCI states of the new serving cell.

[0019] In one aspect of the processor-implemented method, the method may further include: in response to the cell handover command, determining that a timing advance (TA) value has not yet been provided for the target cell in the cell handover command; and receiving the TA value of the target cell via a random access procedure.

[0020] In one aspect of the processor-implemented method, the method may further include: receiving an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and maintaining the indication of the one TCI state as the indicated TCI state of the new serving cell after the random access procedure with the target cell is successfully completed.

[0021] In one aspect of the method implemented by the processor, one or more activated TCI states of the new serving cell may include only the indicated TCI state of the new serving cell, and among the one or more activated TCI states, TCI states other than the indicated TCI state are deactivated or not considered.

[0022] In one aspect of the processor-implemented method, the method may further include: receiving an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and after the random access procedure with the target cell is successfully completed, determining, based on the cell handover command, one of the following: an indication to maintain at least one of the one or more activated TCI states but not the one TCI state; an indication to maintain the one TCI state but not the one or more activated TCI states; or an indication to maintain at least one of the one or more activated TCI states and the one TCI state.

[0023] In one aspect of the processor-implemented method, the method may further include: receiving an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and determining, after the random access procedure with the target cell is successfully completed, not to maintain the indication of the one TCI state as the indicated TCI state of the new serving cell.

[0024] In one aspect of the processor-implemented method, the determination of an indication not to maintain the TCI state may be based on: a CORESET index value associated with a common search space (CSS) of at least one type of physical downlink control channel (PDCCH), and a configuration having at least one field value corresponding to an indication not to apply the TCI state. The method further includes: based on the determination, applying a quasi-co-location (QCL) source to monitor at least one CSS on at least one CORESET, based on a reference signal selected for the random access procedure.

[0025] In one aspect of the method implemented by the processor, performing a random access procedure with the target cell may include: if the corresponding Signal Synchronization Block (SSB) or Quasi-Co-location (QCL) source SSB has a reference signal received power (RSRP) higher than a threshold, then selecting one of the SSBs or QCL source SSBs corresponding to an indicated TCI state.

[0026] In one aspect of the method implemented by the processor, the method may further include: determining that a timing advance (TA) value was acquired prior to the cell handover command; and that the cell handover command does not include the TA value; and based on the determination, deciding to trigger a random access procedure.

[0027] In one aspect of the processor-implemented method, the method may further include: in response to the cell handover command, determining that a timing advance (TA) value of the target cell has been acquired, and determining one of the following: uplink resources have been configured for the target cell, or the scheduling of the uplink resources is to be monitored; based on the determination, transmitting uplink messages to the target cell using the uplink resources; and determining that a random access procedure is triggered before the uplink messages are successfully transmitted to the target cell, wherein the random access procedure is executed in response to the triggering of the random access procedure.

[0028] In one aspect of the processor-implemented method, the method may further include: receiving an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and maintaining the indication of the one TCI state as the indication TCI state of the new serving cell after the random access procedure with the target cell is successfully completed.

[0029] In one aspect of the processor-implemented method, the method may further include: receiving an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and determining, after the random access procedure with the target cell is successfully completed, not to maintain the indication of the one TCI state as the indicated TCI state of the new serving cell.

[0030] In one aspect of the processor-implemented method, the method may further include: for each of a plurality of candidate cells, receiving from the serving cell one or more corresponding activated Transport Configuration Indicator (TCI) states of the corresponding candidate cell, wherein the plurality of candidate cells includes the candidate cell.

[0031] In one aspect of the method implemented by the processor, the cell handover command may be a Layer 1 / Layer 2 triggered Mobility (LTM) cell handover command.

[0032] The independent claims provide the subject matter based on several aspects. Further aspects are defined in the dependent claims. Attached Figure Description

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

[0034] Figure 1 This is a diagram of an example embodiment of wireless networking between a network system and a user equipment (UE) according to an illustrative aspect of this disclosure; Figure 2 This is a diagram of an example embodiment of a transmission and reception beam for wireless networking between a network device and a user equipment device (UE) according to an illustrative aspect of this disclosure; Figure 3 This is a diagram of an example embodiment of a UE receiving a burst scan beam for a synchronization signal block (SSB) according to an illustrative aspect of this disclosure; Figure 4 This is a diagram of an example embodiment of a Layer 1 / Layer 2 triggered mobility (LTM) scenario according to an illustrative aspect of this disclosure; Figure 5 This is a diagram of an example embodiment of a contention-based random access procedure according to an illustrative aspect of this disclosure; Figure 6A and 6B This is a diagram of an example embodiment of signals and operations between a UE, a central unit (CU), a source distributed unit (DU), and a target DU in relation to an illustrative aspect of this disclosure; Figure 7 This is a diagram of an example embodiment of signals and operations between a UE, a source cell, and a target cell related to the Transmission Configuration Indicator (TCI) state before, during, and after cell handover, according to one aspect of this disclosure; Figure 8 This is a diagram of an example embodiment of signaling and operation between a UE, a source cell, and a target cell in a cell handover scenario without a timing advance (TA) value, according to an illustrative aspect of this disclosure; Figure 9 This is a diagram of an example embodiment of signaling and operation between a UE, a source cell, and a target cell in a cell handover scenario with a timing advance (TA) value, according to an illustrative aspect of this disclosure; Figure 10 This is a flowchart illustrating an example operation of a UE performing cell handover according to one aspect of this disclosure; Figure 11 This is a flowchart illustrating an example operation of cell handover using a network apparatus according to an illustrative aspect of this disclosure; and Figure 12 This is a diagram of an example embodiment of a component of a UE or network device according to an illustrative aspect of this disclosure. Detailed Implementation

[0035] In the following description, certain specific details are set forth in order to provide a thorough understanding of the disclosed aspects. However, those skilled in the art will recognize that the aspects can be implemented even without one or more of these specific details, or by employing other methods, 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 the description of the aspects.

[0036] Throughout this specification, the terms "an aspect" or "a particular aspect" mean that a specific feature, structure, or characteristic described in connection with that aspect is contained in at least one aspect. Therefore, the phrases "in an aspect" or "in a particular aspect" appearing throughout this specification do not necessarily refer to the same aspect. Furthermore, a particular feature, structure, or characteristic may be combined in any suitable manner in one or more aspects.

[0037] The embodiments described in this disclosure can be implemented in wireless networking devices, such as, but not limited to, devices utilizing wireless networking systems such as WiMAX, GSM (2G), GSM EDGE Radio Access Network (GERAN), General Packet Radio Service (GPRS), Universal Mobile Telecommunications System based on Basic Wideband Code Division Multiple Access (W-CDMA) (UMTS (3G), High-Speed ​​Packet Access (HSPA), Long Term Evolution (LTE), LTE-Advanced, Enhanced LTE (eLTE), 5G New Radio (5GNR), 5G Evolution, 6G (and later versions), and 802.11ax (Wi-Fi 6). The term "eLTE" here refers to LTE evolution connected to a 5G core network. LTE is also referred to as Evolved UMTS Terrestrial Radio Access (EUTRA) or Evolved UMTS Terrestrial Radio Access Network (EUTRAN).

[0038] Because a UE may move from one area to another, the handover or mobility process is crucial for supporting continuous communication between the UE and the network (without interruption or at least minimal interruption). In the example, the UE may be configured to monitor one or more reference signals (e.g., SSB, Channel State Information Reference Signal (CSI-RS), DL Reference Signal (RS)) from one or more network devices, perform signal measurements on (one or more) reference signals, and report these measurements to the network, thereby enabling a decision to hand over the UE to a neighboring cell (e.g., when a signal quality degradation is detected). Handover initiation is typically done by the network side. In the 5G NR example, handover initiation or handover commands may be signaled via higher-layer signaling (e.g., Layer 3 or Radio Resource Control (RRC) signaling). Higher-layer signaling may involve the network and therefore may have high latency. In various cases, the UE can benefit from a more efficient handover process triggered by lower-layer signaling (e.g., L1 / L2 signaling), which has lower latency compared to higher-layer signaling. As used in this paper, a handover triggered by lower-layer signaling can be referred to as lower-layer triggered mobility (LTM). In some cases, the candidate cell for LTM can be referred to as an LTM candidate cell.

[0039] As used herein, the term "cell handover" means and refers to any change of a cell, whether triggered by Layer 1 signaling, Layer 2 signaling, and / or Layer 3 signaling, and / or other signaling. Cell handover can be for a terminal device in RRC connection mode; therefore, cell handover may involve bidirectional signaling between the terminal device and at least one network node of the radio access network (typically at least the source network node and the destination network node of the cell handover). This disclosure primarily uses LTM as an example of cell handover; however, it is intended and should be understood that this disclosure can be used in conjunction with Layer 3 handover or any cell handover.

[0040] This disclosure may use the term "serving cell" to refer to a network node or network device (or a portion thereof) that provides services to the UE, the term "candidate cell" to refer to a network node or network device (or a portion thereof) that is a potential target of a cell handover command, and the term "target cell" to refer to a network node or network device (or a portion thereof) that is the target of a cell handover command. In some examples, the LTM target may also be the serving cell (e.g., the target may be "SCell," i.e., the secondary cell in carrier aggregation).

[0041] As used herein, the terms “transmit to,” “receive from,” and “cooperate with” (and their variations) include communication that may or may not involve communication through one or more intermediate devices or nodes. The term “acquire” (and its variations) includes initial acquisition or reacquisition after initial acquisition. The term “connection” can refer to a physical connection or a logical connection.

[0042] This disclosure specifies that, prior to a cell handover command from its serving cell to a target cell, the UE maintains the active TCI state of the target cell; and further specifies that, after the cell handover to the target cell, which becomes the new serving cell, the UE maintains such an active TCI state as the active TCI state of the new serving cell. In embodiments, the UE also maintains the indicated TCI state for the target cell provided before the cell handover as the indicated TCI state for the new serving cell. The advantages of this aspect include: reducing or eliminating data communication readiness delays after the UE and the target cell successfully complete the random access procedure, thereby improving time and resource utilization at both the UE and the new serving cell.

[0043] Figure 1 This is a diagram illustrating an example of wireless networking between network system 100 and user equipment (UE) 150. Network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network devices 130 (e.g., test devices). Network node 120 will be described in more detail below. As used herein, the term "network device" may refer to any component of network system 100, such as server 110, network node 120, network device 130, any of the foregoing components(s), and / or any other component(s) of network system 100. Examples of network devices include, but are not limited to, devices for implementing various aspects of 5G NR, etc. This disclosure describes embodiments related to 5G NR and embodiments relating to aspects defined by the 3rd Generation Partnership Project (3GPP). However, it is contemplated that embodiments related to other wireless networking technologies are also included within the scope of this disclosure.

[0044] The following description provides further details of examples of network nodes. In a 5G NR network, a gNodeB (also known as a gNB) may include, for example, nodes that provide NR user plane and control plane protocol termination to the UE and are connected to the 5G core network (5GC) via an NG interface – for example, according to Section 3.2 of 3GPP TS 38.300 V16.6.0 (2021-06), the contents of which are incorporated herein by reference.

[0045] gNB supports various protocol layers, such as Layer 1 (L1) – the physical layer, Layer 2 (L2) and Layer 3 (L3).

[0046] NR's Layer 2 (L2) is divided into the following sublayers: Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and Service Data Adaptation Protocol (SDAP). For example: o The physical layer provides a transmission channel to the MAC sublayer; o The MAC sublayer provides logical channels to the RLC sublayer; o The RLC sublayer provides RLC channels to the PDCP sublayer; o The PDCP sublayer provides radio bearers to the SDAP sublayer; o The SDAP sublayer provides Quality of Service (QoS) flows to 5GC; o The control channels include the Broadcast Control Channel (BCCH) and the Physical Control Channel (PCCH).

[0047] Layer 3 (L3) includes, for example, Radio Resource Control (RRC) – for example, Section 6 of 3GPP TS 38.300 V16.6.0 (2021-06), the contents of which are incorporated herein by reference.

[0048] A gNB Central Unit (gNB-CU) may include, for example, a logical node that controls the operation of one or more gNB Distributed Units (gNB-DUs). This logical node hosts, for example, the gNB's Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP), or the en-gNB's RRC and PDCP protocols. The gNB-CU terminates the F1 interface connected to the gNB-DU. In this document, the gNB-CU may also be referred to as a CU, Central Unit, Centralized Unit, or Control Unit.

[0049] A gNB Distributed Unit (gNB-DU) includes, for example, a logical node that hosts the Radio Link Control (RLC), Media Access Control (MAC), and Physical (PHY) layers of, for example, a gNB or en-gNB, and its operation is partially controlled by the gNB-CU. A gNB-DU supports one or more cells. A cell is supported by only one gNB-DU. The gNB-DU terminates the F1 interface connected to the gNB-CU. In this document, the gNB-DU may also be referred to as a DU or Distributed Unit.

[0050] As used herein, the term "network node" may refer to any of the gNB, gNB-CU, or gNB-DU, or any combination thereof. A radio access network (RAN) node or network node (such as a gNB, gNB-CU, or gNB-DU, or a portion thereof) may be implemented, for example, using an apparatus having at least one processor and / or at least one memory, wherein the memory has processor-readable instructions ("program") configured to support and / or provide and / or process functions and / or features associated with the CU and / or DU, and / or at least one protocol (sub)layer (e.g., layer 2 and / or layer 3) of the radio access network. Different functional divisions may be employed between central and distributed units. Examples of such apparatuses and components will be provided below. Figure 12 Describe it.

[0051] The gNB-CU and gNB-DU portions may, for example, be co-located or physically separated. The gNB-DU may even be further divided into, for example, two parts, one including processing equipment and the other including an antenna. The Central Unit (CU) may also be referred to as BBU / REC / RCC / C-RAN / V-RAN, O-RAN, or a portion thereof. The Distributed Unit (DU) may also be referred to as RRH / RRU / RE / RU, or a portion thereof. In the various example embodiments of this disclosure below, a network node supporting at least one of the Layer 3 protocols of the Central Unit function or the radio access network may be, for example, a gNB-CU. Similarly, a network node supporting at least one of the Layer 2 protocols of the Distributed Unit function or the radio access network may be, for example, a gNB-DU.

[0052] A gNB-CU can support one or more gNB-DUs. A gNB-DU can support one or more cells, and therefore can support the serving cell of a user equipment (UE) or a candidate cell for handover, dual connectivity and / or carrier aggregation and other procedures.

[0053] User equipment (UE) 150 may be or include wireless or mobile devices, devices having a wireless interface for interacting with a RAN (Radio Access Network), smartphones, in-vehicle devices, Internet of Things (IoT) devices, or machine-to-machine (M2M) devices, and other types of user equipment. Such a UE 150 may include: at least one processor; and at least one memory containing program code; wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the device to perform at least certain operations, such as establishing an RRC connection with the RAN. Examples of UE components will be combined... Figure 12The following description is provided. In an embodiment, UE 150 may be configured to generate messages (e.g., containing a cell ID) to be transmitted wirelessly to the RAN (e.g., to reach and communicate with the serving cell). In an embodiment, UE 150 may generate, transmit, and receive RRC messages containing one or more RRC PDUs (Packet Data Units). Those skilled in the art will understand the RRC protocol and other processes that the UE may perform.

[0054] Continue to refer to Figure 1 In the example of a 5G NR network, network system 100 provides one or more cells that define the coverage area of ​​network system 100. As described above, network system 100 may include a gNB of the 5G NR network, or may include any other means configured to control wireless communications and manage radio resources within the cell. As used herein, the term "resource" may refer to radio resources such as resource blocks (RBs), physical resource blocks (PRBs), radio frames, subframes, time slots, subbands, frequency regions, subcarriers, beams, etc. In embodiments, network node 120 may be referred to as a base station.

[0055] Figure 1 Examples are provided and are for illustrative purposes only, relating to network system 100 and UE 150. Those skilled in the art will understand that network system 100 includes... Figure 1 Components not shown in the diagram, and it will be understood that other user equipment devices can communicate with network system 100.

[0056] Figure 2 This is a diagram of an example embodiment of wireless networking between network device 210 and user equipment device (UE) 150. Network device 210 is configured to form beams 220 in multiple directions, and UE 150 is also configured to form beams 260 in multiple directions. As those skilled in the art will understand, the ability to beamform in multiple directions can be achieved using an arrangement of multiple radiating elements, which may also be referred to as an "array" of radiating elements. Beamforming (also known as spatial filtering) enables directional signal transmission or reception by utilizing individual arrays and / or combining elements in an array in a specific manner, causing signals at specific angles to produce constructive or destructive interference. Transmit beamforming is achieved by controlling the phase and relative amplitude of the transmitted signal at each radiating element in the array to produce desired constructive and destructive interference patterns in a desired wavefront. In contrast, receive beamforming is achieved by combining information from different elements of the array in a manner that prioritizes the observation of radiation in a target spatial region.

[0057] In the example shown, network device 210 (e.g., gNodeB or a portion thereof) and UE 150 may each be equipped with one or more antenna panels or antenna arrays having antenna elements that can be configured to perform beamforming in certain spatial directions and / or in certain spatial angular sectors or widths.

[0058] Continue to refer to Figure 1 Examples of various beams 220 are illustrated for network device 210, and examples of various beams 260 are illustrated for UE 150. As a result of using highly directional beams, some of the network device beams 120 may not be usable with some of the UE beams 160 due to large directional differences. Therefore, in the embodiment, UE 150 “scans” its beams 260, and network device 210 also “scans” its beams 220 to determine which beam pair has the highest signal power and is therefore best suited for communication. Beams that are not perfectly directional may also have the highest signal power due to various propagation conditions. This will be combined with... Figure 3 These scans are described in more detail. After such a beam pairing is identified, UE 150 and network device 210 can use the identified beam to initiate the access procedure for UE 150 to access network device 210.

[0059] Figure 3 This is a diagram of an example embodiment of a UE receiving a burst scan beam for SSB. Using Figure 2 As shown in the example beam diagram, network device 210 sequentially forms beams B1, B2, B3, and B4. Each formation of the beam is referred to as a "burst." Network device 210 can generate bursts at intervals for observation by UE 150. Each time interval between intervals is called a "burst period," which may be longer than the duration of the burst.

[0060] In the 5G NR example, each beam in the burst transmits information about that beam in a so-called Signal Synchronization Block (SSB). Network device 210 (which may be a gNodeB or a portion thereof) transmits the SSB in each beam of the burst. In some examples, network device 210 may operate using one SSB (single-beam operation) or multiple SSBs (multi-beam operation). In an embodiment, UE 150 may receive an SSB burst for each of its received beams. Figure 2 In the example shown with four receiving beams R1, R2, R3, and R4, receiving a burst of all four receiving beams requires four intervals, as... Figure 3As shown. In some examples, the UE 150 can operate using a single beam (e.g., an omnidirectional beam). The SSB of an SS burst can be provided by one or more (co-located or non-co-located) TRPs (transmit-receive points). The duration between bursts is called the "burst periodicity". In 5G NR networks, each SSB burst can last 5 milliseconds, and the burst periodicity can have a default duration of 20 milliseconds.

[0061] In the 5G NR example, each SSB includes System Information (SI) in the form of a Master Information Block (MIB) and multiple System Information Blocks (SIBs). SIs are divided into Minimum SIs and other SIs. Minimum SIs include basic information that can be used by network nodes to access the network and information for acquiring any other SIs. Minimum SIs include the MIB, which contains cell prohibition state information and physical layer information for the cell used to receive further system information (e.g., CORESET#0 configuration). MIBs are periodically broadcast on the Broadcast Channel (BCH). Minimum SIs also include System Information Block 1 (SIB1), which defines the scheduling of other System Information Blocks and contains information for network node access. SIB1 can also be referred to as the Residual Minimum SI (RMSI) and is periodically broadcast on the Downlink Shared Channel (DL-SCH).

[0062] Also refer to Figure 2In the example of 5G New Radio (5G NR) defined by the 3rd Generation Partnership Project (3GPP), a unified Transport Configuration Indicator (TCI) framework is used for beam configuration and / or indication. For example, network device 210 may use a set of TCI states to configure UE 150. Each TCI state may indicate at least one beam direction or a set of beam directions, which may correspond to a reference signal. In the example, the TCI state may be a DL TCI state for downlink (DL) communication from network device 210 to UE 150. In other examples, the TCI state may be a UL TCI state for uplink (UL) communication from UE 150 to network device 210. In a further example, the TCI state may be a combined TCI state for UL and DL communication between network device 210 and UE 150. Network device 210 may use at least a subset of the configured TCI states to “activate” the UE. As used herein, “activating” a TCI state means that UE 150 can monitor signals, such as reference signals, transmitted by network device 210 corresponding to the TCI state. In examples, activation of a TCI state may mean that the UE is configured to monitor at least one reference signal associated with the activated TCI state, for example, for time / frequency tracking and / or path loss measurement. In examples, activation may mean that UE 150 is expected to track at least one reference signal corresponding to the activated TCI state. In some examples, network device 210 may activate one or more configured TCI states in the set and exclude one or more other configured TCI states in the set. Additionally, to communicate with UE 150, network device 210 may select one of the activated TCI states and “indicate” the selected TCI state to UE 150. As used herein, “indicating” a TCI state means that UE 150 can be configured to communicate with network device 210 using a beam (identified by a downlink reference signal) corresponding to the indicated TCI state. In various examples, UE 150 may be prepared to receive an indication of at least one of the activated TCI states and to communicate with network device 210 using the indicated TCI state within a specified time limit.

[0063] Figure 2 and 3 The examples are merely illustrative. In embodiments, the number and direction of network node beams and the number and direction of UE beams can vary and may differ from those of other implementations. Figure 2 and 3 Those shown.

[0064] As explained above, a UE can travel from one area to another, so cell handover or mobility procedures (e.g., Layer 3 handover or LTM) can be important for supporting continuous communication between the UE and the network. Furthermore, when a UE moves from one cell coverage area to another, a more efficient cell handover procedure (such as LTM) can help avoid or at least reduce interference with UE services.

[0065] Figure 4 This is a diagram of an example embodiment of an LTM scenario. For example... Figure 4 As shown, UE 410 can communicate with and be served by network device 420 (e.g., gNB or a portion thereof), as indicated by the solid arrow. UE 410 can be substantially similar to Figure 1 The UE150. Network device 420 can be substantially similar to Figure 1 Network device 110. Network device 420, which is actively or currently serving UE 410, can be referred to as the serving cell. When UE 410 travels toward the edge of a cell or area 402 served by (or within the coverage of) network device 420, a cell handover procedure can be performed to switch UE 410 to a neighboring cell served by, for example, another network device 430, 440. Figure 4 In the example shown, one neighboring cell is served by network device 430, and another neighboring cell is served by network device 440. Network device 440 may cover (or serve) cell or area 406, while network device 430 may cover area 404. In some examples, areas 402, 404, and 406 may partially overlap, as shown. In other examples, areas 402, 404, and 406 may not overlap. In the context of handover, neighboring cells may be referred to as candidate cells. In the context of LTM, neighboring cells may be referred to as LTM candidate cells.

[0066] The term "Layer 1 / Layer 2 Triggered Mobility (LTM)" can also be referred to as L1 / L2 triggered mobility, L1 / 2 inter-cell mobility, L1 / 2 handover, or lower-layer (L1 / 2) mobility. These terms are used interchangeably. An L1 / L2 signal, message, or command sent by a network node to trigger a cell handover at the UE is called a "cell handover command." In LTM, the decision regarding cell handover is based on L1 measurements and is made at the MAC layer of the Distributed Cell (DU). The cell handover command includes a MAC Control Element (MAC CE). The cell targeted by the cell handover command may be referred to herein as the target cell. References will follow. Figure 7-11 A more comprehensive discussion of the mechanism of LTM.

[0067] According to aspects of this disclosure, network device 420 (serving cell) can activate UE 410 using one or more TCI states for one or more candidate cells, and can optionally indicate the activated TCI states available to UE 410 in the event of a cell handover. In this regard, network device 420 can transmit an indication of one or more candidate cells (e.g., network devices 430 and 440), and the activation of a corresponding list of one or more TCI states for each of the one or more candidate cells. Upon detecting a communication or operational degradation with UE 410, serving cell network device 420 can transmit a cell handover command to UE 410 via lower-layer signaling (e.g., L1 / L2 signaling). The cell handover command can indicate a selected cell from one or more candidate cells as the target cell for the cell handover. In response to receiving the cell handover command, UE 410 can switch to communication with the target cell by applying at least one of the corresponding one or more activated TCI states.

[0068] Figure 4 The examples provided are merely illustrative. In embodiments, the number of candidate cells and the number of activated TCI states (or beams) can vary and may differ from those provided. Figure 4 As shown in the diagram.

[0069] The process by which a UE establishes communication with a target cell is called a random access procedure. Random access procedures can be used for initial access, small-scale data transmission during inactivity, and the transition from RRC_Inactive to RRC_Connected. They can also be used for beam failure recovery, connection reconstruction, handover, cell addition, and other procedures that those skilled in the art will recognize.

[0070] There are two types of random access procedures: contention-based random access (CBRA) and contention-free random access (CFRA). Figure 5 This is a diagram illustrating an example of a contention-based random access (CBRA) procedure. In the example shown, the signals include a random access preamble (MSG1) transmitted from UE 550 to network node 510 (e.g., gNodeB or a portion thereof), a random access response (MSG2) transmitted from network node 510 to UE 550, a scheduling transmission (MSG3) transmitted from UE 550 to network node 510, and a contention resolution (MSG4) transmitted from network node 510 to UE 550.

[0071] For MSG1, UE 550 selects the available random access preamble based on information elements in the Signal Synchronization Block (SSB), such as those mentioned above. Figure 3The UE 550 uses a specific time and frequency resource called the Random Access Opportunity (RO) to send a random access preamble (MSG1) to the network node 510. The UE 550 also provides an identifier to the network, called the Random Access Radio Network Temporary Identifier (RA-RNTI), so that the network can address it in the next step.

[0072] For MSG2, network node 110 detects the preamble, calculates various quantities, and sends a Physical Uplink Shared Channel (PUSCH) Uplink (UL) grant to UE 550. This is called a Random Access Response (RAR), which is sent as MSG2 addressed to UE 550, has an associated RA-RNTI, and indicates to UE 550 where and when it can transmit MSG3 on the PUSCH within the frequency range.

[0073] For MSG3, in response to receiving MSG2 from network node 510, UE 550 uses the UL authorization provided in the RAR to send MSG3. Because the RAR provides time resource allocation, UE 550 sends MSG3 to network node 510 at the timing specified by the time resource allocation, and this is a scheduled transmission. This MSG3 can be referred to as a Radio Resource Control (RRC) Connection Request message.

[0074] For MSG4, network node 510 can send MSG4 to UE 550 for contention resolution. Contention resolution can be performed in accordance with the manner specified by 3GPP for 5G NR. After the random access procedure, assuming the contention resolution is successfully resolved, UE 550 becomes connected to network node 510. After connection establishment, various procedures will be handled by gNB-CU according to CU-DU separation. Other aspects of contention-based random access (CBRA) will be understood by those skilled in the art.

[0075] Another type of random access procedure is Contention-Free Random Access (CFRA) (not shown). In CFRA (not shown), network node 510 transmits an assigned random access preamble to UE 550. UE 550 receives the assigned random access preamble and sends it as MSG1 to network node 510 in its random access request. MSG2 and MSG3 are then similar to those described in conjunction with CBRA. Based on the use of the assigned random access preamble, conflict resolution is not required in CFRA. Other aspects of Contention-Free Random Access (CFRA) will be understood by those skilled in the art.

[0076] Now we will combine Figure 6A and 6B Describe the LTM and random access procedures. Figure 6A and6B The diagram illustrates an example of a cell handover process, and it is intended and should be understood that other types of cell handover processes (e.g., Layer 3 handover) are also within the scope of this disclosure. Reference now. Figure 6A and Figure 6B Example signals and operations of LTM and random access procedures related to inter-DU cell handover are shown. The inter-DU scenario is illustrative, and aspects of this disclosure can also be applied to intra-DU scenarios. Where the source DU and destination DU are supported by different CUs, the source DU may be supported by the source CU, and the destination DU may be supported by the destination CU; they may communicate via the Xn interface. As mentioned above, the communication included by the terms "transmit to," "receive from," and "cooperate with" (and variations thereof) may or may not involve communication through one or more intermediate devices or nodes. It is intended that any description referring to a DU should be considered as if the description refers to a network node supporting DU functionality or at least one of the Layer 2 protocols of a Radio Access Network (RAN). It is intended that any description referring to a CU should be considered as if the description refers to a network node supporting CU functionality or at least one of the Layer 3 protocols of a Radio Access Network (RAN).

[0077] The following paragraphs describe various signals and operations. It should be understood that a described signal can have an associated operation, and a described operation can have an associated signal. Therefore, a described signal can also be an operation, and a described operation can also be a signal.

[0078] Prior to signal 601, the UE had already established a connection with the DU (i.e., the source DU) of the serving cell that supports the UE, and had also established a (logical) connection with the CU that supports the DU.

[0079] At signal 601, the UE transmits an L3 measurement report to the source DU, and the source DU receives the L3 measurement report from the UE. Those skilled in the art will understand that the L3 measurement report may include, for example, an average measurement sample of a reference signal from the serving cell. The L3 measurement report may indicate, for example, that the UE is approaching the cell edge and therefore should initiate a handover procedure. At signal 602, the source DU forwards the report by transmitting it to the CU, and the CU receives the L3 measurement report from the source DU. At operation 603, the CU performs a handover (HO) decision based on the L3 measurement report regarding whether a handover should be prepared. In the illustrated embodiment, the CU determines that a handover should be prepared.

[0080] At signal 604, the CU transmits a UE context setup request to the target DU to prepare for handover of the target DU 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 signal 605, the target DU provides confirmation by transmitting a UE context setup response to the CU, and the CU receives the UE context setup response from the target DU. Although one target DU is shown, there may be more than one target DU if multiple candidate cells exist. The signals at 604 and 605 can be used for each target DU and multiple candidate cells. The following description will refer to one or more candidate cells to indicate that one or more candidate cells may exist, and where appropriate, will refer to one or more target DUs supporting one or more candidate cells. If the target DU and the source DU are supported by different CUs, these CUs can communicate using the Xn interface. For convenience, only one CU (the CU supporting the source DU) is shown, but the disclosed techniques are also intended to be applied to multi-CU scenarios.

[0081] At signal 606, the CU transmits a UE context modification request to the source DU to modify the UE context in the source DU if necessary, and to provide target cell information (e.g., target cell RS configuration, activated or indicated TCI status, etc.). The source DU receives the UE context modification request from the CU, modifies the UE context (if necessary), and receives the target cell information. At signal 607, the source DU provides confirmation by transmitting a UE context modification response to the CU, and the CU receives the UE context modification response from the source DU.

[0082] At signals 604-607, the CU, one or more target DUs, and source DUs can coordinate with each other regarding timing advance acquisition and configuration of one or more candidate cells. Timing advance refers to information used by the UE to time its uplink transmissions to the network node so that they are aligned with the reception time window upon arrival at the network node. This information may be referred to herein as a timing advance value or TA value, and the process of acquiring the timing advance value may be referred to herein as timing advance acquisition, TA acquisition, acquiring timing advance, or acquiring TA (or variations thereof). As mentioned above, the term "acquisition" (and variations thereof) includes in-first instance acquisition or re-acquisition after the first instance. In embodiments, the source DU and one or more target DUs can coordinate (via the CU) regarding the method by which the UE acquires the TA. In embodiments, the UE may acquire a separate TA value for each candidate cell.

[0083] In embodiments, TA can be obtained based on random access (RA) procedures (CFRA or CBRA), such as, but not limited to, RA procedures triggered by physical downlink control channel (PDCCH) commands, UE-triggered RA procedures, and / or RA procedures triggered by higher layers from network nodes (except for L3 handover commands), etc. In embodiments, TA can also be obtained based on non-RA procedure methods, such as, but not limited to, TA acquisition based on sounding reference signals (SRS), mechanisms based on receive timing differences (such as those in LTE), and / or UE-based TA measurements, etc. Such RA-based and non-RA-based TA acquisition methods are within the scope of this disclosure.

[0084] At operation 608, the CU creates an RRC reconfiguration message, which includes measurement configuration for L1 cell change, configuration of ready cells, and TA acquisition configuration and triggering for candidate cells. In an embodiment, the RRC reconfiguration message may include TA configuration if CU involvement is required later (during the execution phase). TA configuration may, for example, specify the method by which the UE acquires TA. In an embodiment, the TA acquisition method may be configured / triggered by the CU (in cooperation with the source DU) based on L3 measurements.

[0085] At signal 609, the CU transmits an RRC reconfiguration message to the source DU using a downlink (DL) RRC message, and the source DU receives the RRC reconfiguration message from the CU. As described above, the RRC reconfiguration message may include the aforementioned TA configuration and activated or indicated TCI status information. At signal 610, the source DU transmits the RRC reconfiguration message to the UE to forward it to the UE, and the UE receives the RRC reconfiguration message from the source DU. The UE performs reconfiguration based on the RRC reconfiguration message. At signal 611, the UE responds by transmitting an RRC reconfiguration completion message to the source DU using an uplink (UL) RRC message, and the source DU receives the RRC reconfiguration completion message from the UE. At signal 612, the source DU transmits the RRC reconfiguration completion message to the CU to forward it to the CU, and the CU receives the RRC reconfiguration completion message from the source DU. In an embodiment, signals 609-612 can be described as part of a logical connection between the UE and the CU, such that the CU transmits an RRC message to the UE, and the UE receives the RRC message from the CU.

[0086] In this embodiment, the signals and operations 601-612 described above can be referred to as the preparation phase. The execution phase follows the preparation phase.

[0087] During the execution phase, the UE provides periodic L1 measurement reports based on its configuration. Those skilled in the art will understand L1 measurement. L1 measurement can measure the signal power of a list of reference signals configured by the network. For example, L1 measurement can measure the signal power of a reference signal corresponding to an SSB in an activated TCI state. At signal 613, the UE periodically transmits L1 measurement reports to the source DU, and the source DU receives periodic L1 measurement reports from the UE.

[0088] At operation 614, the source DU determines whether to trigger the UE to acquire the TA of the group of candidate cells (i.e., the candidate cells for handover configured by the CU at operation 608) based on the received L1 measurement report.

[0089] At operation 615, the UE performs TA acquisition for one or more candidate cells using the TA acquisition method specified in the RRC reconfiguration message of operation 608. As described above, TA can be acquired based on a random access (RA) procedure (CFRA or CBRA), such as, but not limited to, an RA procedure triggered by a physical downlink control channel (PDCCH) command, a UE-triggered RA procedure, and / or a higher-layer RA procedure triggered from a network node (except for L3 handover commands), etc. In embodiments, TA can be acquired based on non-RA procedure methods, such as, but not limited to, TA acquisition based on a sounding reference signal (SRS), a mechanism based on receive timing difference (such as mechanisms in LTE), and / or TA measurement based on the UE, etc. Such RA-based and non-RA-based TA acquisition methods are within the scope of this disclosure. After operation 615, if the TA acquisition procedure is successful, the UE may have TA values ​​for one or more candidate cells before triggering a cell handover. If the TA acquisition procedure is unsuccessful, the UE will not have TA values ​​for one or more candidate cells.

[0090] At signal 616, the UE continues to report L1 measurements and periodically transmits L1 measurement reports to the source DU, and the source DU receives periodic L1 measurement reports from the UE. At operation 617, the source DU determines whether the UE should change its serving cell. In an embodiment, for example, if the L1 measurement is below a threshold, the source DU may determine that the UE should change its serving cell. Once the source DU determines that the UE should switch to a cell (e.g., a target cell supported by the target DU), the source DU triggers the cell handover using a cell handover command (e.g., MAC CE).

[0091] At signal 618, the source DU transmits a cell handover command (e.g., MAC CE) to the UE, and the UE receives the cell handover command (e.g., MAC CE) from the source DU. In an embodiment, the cell handover command may include the TA value of the target cell. In an embodiment, the cell handover command may include a TA configuration for the UE to use during and / or after cell handover. The source DU can obtain the TA configuration by receiving an RRC message at signal 609.

[0092] In response to a cell handover command, the UE applies the RRC configuration of the target cell of the target DU indicated by the cell handover command to hand over to the target DU / target cell as the serving cell. In an embodiment, the UE may be configured to perform a random access (RA) procedure for the target cell and target DU, as shown in signals 619 and 620. However, in an embodiment, if the UE has already obtained the TA value of the target cell, the UE may be configured not to perform the RA procedure for the target cell / target DU.

[0093] At signal 621, to initiate communication with the target DU, the UE uses its configured uplink (UL) resources to transmit an RRC reconfiguration complete message to the target DU, and the target DU receives this RRC reconfiguration complete message from the UE. At signal 622, the target DU uses UL RRC message forwarding to forward the RRC reconfiguration complete message to the CU, and the CU receives this RRC reconfiguration complete message from the target DU. At signal 623, the CU transmits a UE context release command / request to the source DU to release the UE context from the source DU, and the source DU receives this UE context release command / request from the CU. In response to the UE context release command / request, the source DU releases the UE context. At signal 624, the source DU transmits a UE context release complete message to the CU, and the CU receives this UE context release complete message from the source DU. At operation 625, the CU performs a path handover to the target DU, which becomes the new DU supporting the serving cell.

[0094] Figure 6A and Figure 6B The signals and operations described herein are merely illustrative, and variations are considered to be within the scope of this disclosure. For example, signals and operations may assume a single TA value for each Physical Cell ID (PCI). In embodiments, to cover multi-TRP (Multiple Transmitter Receiver) scenarios, the UE may be configured and required to obtain multiple TAs for the PCI, such as different TA values ​​for different sets of TCI states. In embodiments, signals and operations may include... Figure 6A and Figure 6B Other content not shown. In this embodiment, signals and operations may not include... Figure 6A and Figure 6BEach signal and operation is shown. In an embodiment, the signals and operations may be arranged differently from... Figure 6A and Figure 6B The sequence shown is used to implement this. Such and other embodiments are considered to be within the scope of this disclosure.

[0095] Various scenarios may occur regarding cell handover. Figure 7-9 This involves various cell handover scenarios, which will now be described. In general, Figure 7 This relates to a cell handover scenario in which the activated or indicated TCI state received before or during a cell handover command is no longer maintained after a successful cell handover. Figure 8 This involves a cell handover scenario where the TA value is not provided in the cell handover command. Figure 9 This involves a cell handover scenario where, before or during the cell handover command, the TA value and uplink transmission resources are configured in the UE (or the monitoring and scheduling of UL resources are configured in the UE). Figure 7-9 In this process, signals and operations are implemented between the UE, the serving cell, and the target cell to perform cell handover. One or more of the signals and operations can be combined. Figure 6A and 6B This is achieved through LTM operations. The UE can be similar to... Figure 1 and 2 The serving cell and target cell may be similar to network devices 420 and / or 430.

[0096] about Figure 7-9 The following paragraphs describe various signals and operations. It should be understood that a described signal can have an associated operation, and a described operation can have an associated signal. Therefore, a described signal can also be an operation, and a described operation can also be a signal. Furthermore, Figure 7-9 The procedure includes many of the listed steps, but aspects of the operation may include additional steps before, after, and between the listed steps. In some aspects, one or more of the listed steps may be omitted or performed in a different order. Such variations are all considered to be within the scope of this disclosure.

[0097] Figure 7 This is a diagram of an example embodiment of a cell handover operation, wherein the activated or indicated TCI state received before or during the cell handover command is no longer maintained after the successful completion of the cell handover. Signals 710 and 715 correspond to one scenario, and signals 720 and 725 correspond to another scenario. Before signal 710 or 720, the UE has already established a connection with the DU supporting the serving cell and has already established a (logical) connection with the CU supporting that DU.

[0098] In the scenarios of signals 710 and 715, prior to the cell handover command, the UE is provided with the activation of the target cell's TCI state and an indication of at least one TCI state of the target cell. At signal 710, the serving cell transmits a MAC CE to the UE, which includes the activation of the target cell's TCI state, and the UE receives the MAC CE. At signal 715, the serving cell transmits an indication of at least one activated TCI state of the target cell to the UE, and the UE receives the indication of the activated TCI state of the target cell. After signal 715, the UE receives the cell handover command (not shown). The indicated TCI state (index) can be a combined TCI state, meaning it is used for both downlink and uplink communication. Alternatively, the indicated TCI state (index) can be a pair of TCI states (i.e., a pair of downlink and uplink TCI states), or it can be an indicated TCI state (index) (e.g., a downlink or uplink TCI state).

[0099] In scenarios 720 and 725, the active TCI state of the target cell is provided to the UE before the cell handover command, and the indicated TCI state is provided in the cell handover command. At signal 720, the serving cell transmits a MAC CE to the UE, which includes the activation of the TCI state of the target cell, and the UE receives the MAC CE. At signal 725, the serving cell transmits a MAC CE to the UE, which includes a cell handover command with an indication of the active TCI state of the target cell, and the UE receives the MAC CE.

[0100] In various examples (not shown), the UE may receive a TCI state (index) in a cell handover command, which is used to activate and indicate at least one TCI state. In various examples, the UE may not have received any activation command for one or more TCI states prior to the cell handover, and may receive activation in the cell handover command. In such examples, the at least one TCI state provided in the cell handover command is an activated and indicated TCI state.

[0101] Following both signals 715 and 725, the operation proceeds to operation 730. At operation 730, a random access procedure is triggered before the successful completion of the cell handover and before the UE transmits an uplink message to the target cell (e.g., RRC reconfiguration completion signal 621 or other message indicating completion of the cell handover). In various examples, the random access procedure may be triggered before at least one UL message is successfully provided from the UE to the target cell for any of the following reasons: N retransmissions of the UL message (e.g., the configurable maximum number of retransmissions has been reached), or at least one timer for monitoring the provision of UL message transmission expires (e.g., the maximum amount of time the UE needs to attempt to transmit the UL message on the provided UL authorization has been reached), or the quality of at least one RS in the TCI state is observed to be below a threshold, or for any other reason.

[0102] Continuing with operation 730, the UE and the target cell execute and successfully complete the random access procedure, and the target cell becomes the UE's new serving cell. The random access procedure can be successfully completed by the UE transmitting at least one UL message indicating the completion of the cell handover procedure to the target cell, such as an RRC configuration completion message (621, Figure 6) or any message indicating completion of the cell handover to the target cell. In various examples, the UL message may be a MAC CE. The successful completion of the random access procedure clears the active and indicated TCI states of the target cell, and the UE subsequently continues without an active or indicated TCI state for the new serving cell. Instead, at operation 735, the UE prepares for uplink (UL) and downlink (DL) communication by measuring the DL reference signal (RS) selected for the random access procedure in operation 730. At operation 740, the UE transmits an L1 measurement report (e.g., L1-RSRP) to the new serving cell based on the measurement of the DLRS, and the new serving cell receives the L1 measurement report.

[0103] The new serving cell can determine which TCI states to activate based on the L1 measurement report. At signal 745, the new serving cell transmits a reference signal to the UE corresponding to the activated TCI states, and the UE monitors / tracks / receives the reference signal of the activated TCI states.

[0104] At operation 750, the UE tracks the activated TCI state (e.g., it monitors at least one reference signal associated with the activated TCI state, for example, for time / frequency tracking and / or path loss measurement). At signal 755, the new serving cell transmits downlink control information (DCI) including an indication of one of the activated TCI states, and the UE receives the DCI. At operation 760, the UE applies the indicated TCI state, and at block 765, the UE becomes ready to communicate with the new serving cell based on the indicated TCI state.

[0105] In summary, after the random access procedure at point 730 is completed, Figure 7 The signals and operations do not apply the activated or indicated TCI state of the target cell to the new serving cell. Therefore, signals and operations 735-760 are required before the UE can perform data communication with the new serving cell, resulting in a delay between the completion of the random access procedure and data communication. This delay is explained below. Figure 8 and Figure 9 The signals and operations shown are reduced or eliminated.

[0106] Figure 8 This involves a cell handover scenario where a TA value is not provided in the cell handover command. In various examples, the UE may obtain / receive the TA value before the cell handover command for the target cell, but the cell handover command may not provide the UE with a TA value. In this case, the UE may assume that it has not been provided with the TA value for the target cell (even though it previously obtained that value). Alternatively, in various examples, the UE may determine that a previously obtained TA value is still valid even if it is not provided in the cell handover command. In various examples, the UE's determination can be configurable; that is, if the cell handover command does not provide a TA value but the UE has obtained that value before the cell handover, the configuration can be configured to cause the UE to determine to use the previous TA value, or the configuration can be configured to cause the UE to assume that no TA value was provided. Figure 8 Including with Figure 7 The same signals 710 and 715, as well as the same signals 720 and 725. After both signals 715 and 725, option 1 (signals and operations 830-834) or option 2 (signals and operations 840-844) can be performed.

[0107] Both Options 1 and 2 involve the UE and the target cell performing and successfully completing a random access procedure, making the target cell the new serving cell, and then maintaining at least the active TCI state of the target cell as the active TCI state of the new serving cell. Option 1 additionally maintains the indicated TCI state of the target cell as the indicated TCI state of the new serving cell, while Option 2 does not. In Option 2, the indicated TCI state is not maintained, and the UE can assume that the reference signal used for downlink and uplink communication is the selected DL RS of the random access procedure until the UE receives an indication for at least one active TCI state.

[0108] Regarding option 1, at operation 830, the UE determines that no TA value is provided in the cell handover command (i.e., in this scenario, it is assumed that it does not have the TA value for the target cell), and the UE stores / maintains a list of active TCI states and indicated TCI states (if available / if indicated). In various examples, if a TCI state (index) is provided in the cell handover command (e.g., at operation 725), the TCI state (index) can be stored as the active and / or indicated TCI states at operation 830. At operation 832, a random access procedure is triggered, and the UE and the target cell execute the random access procedure, and the UE successfully completes the random access procedure. In various examples, even if a timing advance (TA) value is obtained before the cell handover command, the random access procedure can be triggered based on the determination that the cell handover command does not include a TA value. The UE obtains the TA value of the target cell via the random access procedure. After successfully completing the random access procedure (i.e., after the cell handover), at operation 834, the UE maintains the active TCI state of the target cell to the active TCI state of the new serving cell, and also maintains the indicated TCI state of the target cell to the indicated TCI state of the new serving cell. Maintaining the indicated TCI state allows the UE and the new serving cell to immediately initiate data communication after the random access procedure, without interrupting the handover. Figure 7 The delay associated with the signal and operation 735-760.

[0109] Regarding option 2, operation 840 is the same as operation 830, and operation 842 is the same as operation 832. After successfully completing the random access procedure, at operation 844, the UE maintains the active TCI state of the target cell to the active TCI state of the new serving cell, but does not maintain the indicated TCI state of the target cell to the indicated TCI state of the new serving cell. Maintaining the active TCI state allows the UE and the new serving cell to avoid... Figure 7Signals and operations 735-750 are required in Option 2. Therefore, for the new serving cell, signals and operations 755-765 are still needed to indicate the TCI status so that the UE and the new serving cell can perform data communication. However, compared to... Figure 7 Compared to the previous method, option 2 still reduces the delay in data communication readiness.

[0110] Figure 9 This involves a cell handover scenario where, before or during the cell handover command, the TA value and uplink transmission resources are configured in the UE (or the monitoring and scheduling of UL resources are configured in the UE). In such a scenario, with... Figure 7 compared to, Figure 9 Option 1 or Option 2 shown can be used to reduce latency in data communication readiness. Both Option 1 and Option 2 involve the UE and the target cell performing and successfully completing a random access procedure, making the target cell the new serving cell, and then maintaining at least the active TCI state of the target cell as the active TCI state of the new serving cell. Option 1 additionally maintains the indicated TCI state of the target cell as the indicated TCI state of the new serving cell, while Option 2 does not. In Option 2, without maintaining the indicated TCI state, the UE can assume that the reference signal used for downlink and uplink communication is the selected DL RS of the random access procedure until the UE receives an indication for at least one active TCI state.

[0111] Regarding option 1, at operation 910, the UE determines that a TA value has been provided for the target cell, and the UE is configured for UL transmission for the target cell (either configured with UL resources or configured to monitor downlink control information to provide UL resources). At operation 912, the UE attempts to transmit uplink messages to the target cell using the TA value and UL transmission resources (e.g., Figure 6B (RRC reconfiguration complete message 621 or other message indicating completion of cell handover). In Option 1 scenario, the attempted transmission will not succeed immediately. At operation 914, before the attempted transmission completes, the UE determines to trigger a random access procedure for the target cell, and the UE stores a list of active TCI states and the indicated TCI states (if available). In various examples, the random access procedure may be triggered for the following reasons: N retransmissions of the UL message (e.g., the configurable maximum number of retransmissions has been reached), or at least one timer provided for monitoring UL message transmission has expired (e.g., the maximum amount of time the UE needs to attempt to transmit UL messages on the provided UL authorization has been reached), or the quality of at least one RS of the TCI state is observed to be below a threshold, or for any other reason.

[0112] At block 916, the UE and the target cell perform and successfully complete the random access procedure, and the target cell becomes the new serving cell. The random access procedure can be successfully completed by the UE transmitting at least one UL message indicating the completion of the cell handover process to the target cell, such as an RRC configuration completion message (621, Figure 6), or any message indicating completion of the cell handover to the target cell. In various examples, the UL message can be a MAC CE. After successfully completing the random access procedure, at operation 918, the UE maintains the active TCI state of the target cell to the active TCI state of the new serving cell, and maintains the indicated TCI state of the target cell to the indicated TCI state of the new serving cell. Maintaining the indicated TCI state allows the UE and the new serving cell to perform data communication immediately after the random access procedure is completed, without prior communication with the target cell. Figure 7 The delay associated with the signal and operation 735-760.

[0113] Regarding option 2, the signals and operations 920-926 are the same as those in 910-916. After successfully completing the random access procedure, at operation 928, the UE maintains the active TCI state of the target cell to the active TCI state of the new serving cell, but does not maintain the indicated TCI state of the target cell to the indicated TCI state of the new serving cell. Maintaining the active TCI state allows the UE and the new serving cell to avoid... Figure 7 Signals and operations 735-750 are required in Option 2. Therefore, for the new serving cell, signals and operations 755-765 are still needed to indicate the TCI status so that the UE and the new serving cell can perform data communication. However, compared to... Figure 7 Compared to the previous method, option 2 still reduces the delay in data communication readiness.

[0114] Therefore, with Figure 7 Compared to signals and operations, Figure 8 and Figure 9 The signaling and operation reduce or eliminate delays in data communication readiness after the UE and target cell have successfully completed the random access procedure, which leads to improved time and resource utilization for the UE and network system.

[0115] Figure 7-9 The signals and operations described are merely examples, and variations are considered to be within the scope of this disclosure.

[0116] As a variant example, for downlink control reception at the target cell, for a CORESET with index 0 and / or a CORESET other than index 0 associated with a common search space (CSS) set other than the Type-3-PDCCH (Physical Downlink Control Channel) CSS set, if followUnifedTCI-State is not enabled, the UE may assume that it has not yet been indicated with a TCI state for the target cell (new serving cell). Those skilled in the art will understand CORESET, CSS, and PDCCH, as well as their parameters and operations.

[0117] As another example of a variation, for downlink control reception at the target cell, for a CORESET index value associated with a common search space (CSS) of at least one type of physical downlink control channel (PDCCH), if the configuration includes at least one field corresponding to an indication that no TCI state is applied, the UE can determine that it has not yet been indicated with a TCI state for the target cell. Based on this determination, the UE can apply a quasi-co-location (QCL) source to monitor at least one CSS on at least one CORESET based on a reference signal selected for the random access procedure.

[0118] In some variants, only the indicated TCI state remains the active TCI state, and all other TCI states are deactivated.

[0119] In some variations, the cell handover command may include configuration for which TCI states to maintain. After the UE successfully completes the random access procedure with the target cell, the UE may determine, based on the indication in the cell handover command, to maintain the active TCI state but not the indicated TCI state, or maintain the indicated TCI state (which is also the active TCI state) but not (other) active TCI states, or maintain both the indicated TCI state and the active TCI state. In another example, the UE may be pre-configured to perform one of these actions (maintain / not maintain) after receiving the cell handover command and successfully completing the random access procedure, for example, when an RA procedure is triggered before the cell handover is complete. Alternatively, whether the UE determines to maintain one or more of the TCI states (the indicated and active TCI states, or only the active TCI state, or only the indicated TCI state) can be configured via RRC (and can be configured for each target cell). When the TCI state is maintained as active rather than indicated, the target cell may be allowed to select the indicated TCI state after the cell handover is complete (e.g., based on the random access procedure). In another example, when the UE maintains only the indicated TCI state (which is also one of the active TCI states, while other previously active TCI states are now deactivated / inactive), this allows the network to communicate with the UE after cell handover and reduces the UE burden by not needing to monitor all previously active TCI states (e.g., the target cell can wait for the latest L1 report to determine the activation of the TCI state set, while the UE can still be served using the indicated TCI state). In the example where the UE is configured to maintain both the indicated TCI state and the active TCI state, this enables communication using the indicated TCI state while the UE is monitoring other active TCI states for low-latency beam handover in the target cell.

[0120] In some variants, during the random access procedure, if the corresponding Signal Synchronization Block (SSB) or Quasi-Co-location (QCL) source SSB has a reference signal received power (RSRP) higher than a threshold, the UE can select the SSB or QCL source SSB corresponding to the indicated TCI state.

[0121] In some variants, TCI status can be individually activated and indicated for each candidate cell.

[0122] As another example of a variation, in various embodiments, such as combining Figure 7-9The storage / maintenance of the TCI state can be configurable. This configuration can be provided using RRC signaling. This configuration can be part of a candidate cell configuration (e.g., LTM configuration). This configuration can be specific to a particular cell or a set / group of candidate cells. This configuration can indicate whether the UE is configured to store / maintain the active TCI state for the target cell. In various examples, this configuration can configure the UE to store the activation (and / or indication) of the TCI state for intra-DU cells. In various examples, this configuration can configure the UE not to store the activation (and / or indication) of the TCI state for inter-DU cells. Whether the cell is intra-DU or inter-DU may not be visible to the UE, and the UE can simply apply this configuration. This configuration can indicate whether the UE is not configured to store / maintain the active TCI state for the target cell. This configuration can indicate whether the UE is configured to store / maintain the indicated TCI state (i.e., the indicated TCI state is maintained and it is also the active TCI state). In various examples, a cell handover command can indicate whether the TCI state for the target cell is maintained as active. In various examples, the cell handover command may indicate whether the indicated TCI state for the target cell is maintained as indicated. Such and other variations are considered to be within the scope of this disclosure.

[0123] Now for reference Figure 10 The flowchart shows an example of UE operation. Figure 10 Operations cover Figure 8 and Figure 9 Both, and covering Figure 8 The two options and Figure 9 Two options are provided. At block 1010, the operation involves receiving one or more activated Transport Configuration Indicator (TCI) states for a candidate cell from the serving cell. At block 1020, the operation involves receiving a cell handover command from the serving cell for handing over from the serving cell to the candidate cell, wherein the candidate cell is the target cell of the cell handover command. At block 1030, the operation involves performing a random access procedure with the target cell in response to the cell handover command, wherein after the random access procedure is successfully completed, the target cell becomes the new serving cell of the UE. At block 1040, the operation involves maintaining one or more activated TCI states as the activated TCI states of the new serving cell after the random access procedure with the target cell is successfully completed.

[0124] Figure 10 The operations described are exemplified. In some aspects, these operations may include additional steps before, after, and between the listed steps. In some aspects, one or more of the listed steps may be omitted or performed in a different order. Such variations are all considered to be within the scope of this disclosure.

[0125] Now for reference Figure 11 The flowchart shows an example of target cell operation. Figure 11 Operations cover Figure 8 and Figure 9 Both, and covering Figure 8 The two options and Figure 9 Two options are provided. At block 1110, the operation involves transmitting multiple Transport Configuration Indicator (TCI) states that can be activated for a candidate cell to the serving cell of the user equipment (UE), wherein this transmission occurs before a cell handover command for the UE to hand over from the serving cell to the candidate cell. At block 1120, the operation involves performing a random access procedure with the UE after the cell handover command, wherein after the random access procedure is successfully completed, the candidate cell becomes the new serving cell of the UE. At block 1130, the operation involves communicating with the UE using multiple activated TCI states as the activated TCI states of the new serving cell after the random access procedure with the UE is successfully completed, wherein this communication occurs if the new serving cell has not transmitted any activated TCI states to the UE.

[0126] Figure 11 The operations described are exemplified. In some aspects, these operations may include additional steps before, after, and between the listed steps. In some aspects, one or more of the listed steps may be omitted or performed in a different order. Such variations are all considered to be within the scope of this disclosure.

[0127] Now for reference Figure 12 This diagram illustrates a block diagram of example components of a UE or network device. The device includes electronic storage 1210, a processor 1220, memory 1250, and a network interface 1240. The various components can be communicatively coupled to each other. The processor 1220 can 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-a-chip (SoC), or any other type of processor. The memory 1250 can be a volatile type of memory (e.g., RAM) or a non-volatile type of memory (e.g., NAND flash memory). The memory 1250 includes processor-readable instructions executable by the processor 1220 to cause the device to perform various operations, including those mentioned herein, such as... Figure 3 and 5 -11 operation.

[0128] Electronic storage device 1210 can be and includes any type of electronic storage device for storing data, such as hard disk drives, solid-state drives, and / or optical disks, as well as other types of electronic storage devices. Electronic storage device 1210 stores processor-readable instructions for inducing the device to perform its operations, and stores data associated with such operations, injects data related to the 5G NR standard, and other data. Network interface 240 can implement wireless networking technologies such as 5G NR and / or other wireless networking technologies.

[0129] Figure 12 The components shown are merely examples, and those skilled in the art will understand that the apparatus includes other components not shown, and may include multiples of any of the shown components. Such and other embodiments are considered to be within the scope of this disclosure.

[0130] Further embodiments of this disclosure include the following examples.

[0131] Example 1-1. A network device supporting candidate cells, the network device comprising: One or more processors; and At least one memory storing instructions that, when executed by the one or more processors, cause the network device to at least: A serving cell transmission to a user equipment (UE) may be activated for one or more Transport Configuration Indicator (TCI) states of the candidate cell, wherein the transmission occurs prior to a cell handover command for the UE to hand over from the serving cell to the candidate cell; Following the cell handover command, a random access procedure with the UE is executed. After the random access procedure is successfully completed, the candidate cell becomes the new serving cell; and After the random access procedure with the UE is successfully completed, communication with the UE is conducted using at least one of the one or more activated TCI states as one or more activated TCI states of the new serving cell. The communication occurs when the new serving cell does not transmit one or more activated TCI states to the UE.

[0132] Example 1-2. A network apparatus according to Example 1-1, wherein, when performing a random access procedure with the UE, the instruction, when executed by the one or more processors, causes the network apparatus to at least: transmit the timing advance (TA) value of the candidate cell to the UE.

[0133] Example 1-3. A network apparatus according to Example 1-1 or 1-2, wherein the instructions, when executed by the one or more processors, further cause the network apparatus to at least: after a successful completion of a random access procedure with the UE, communicate with the UE using one of the one or more activated TCI states as the indicated TCI state of the new serving cell. The communication occurs when the new serving cell does not transmit the indicated TCI state to the UE.

[0134] Examples 1-4. The network apparatus according to Examples 1-3, wherein one or more activated TCI states of the new serving cell include only the indicated TCI state of the new serving cell. Of the one or more activated TCI states that can be activated, the TCI states other than the indicated TCI state are deactivated.

[0135] Examples 1-5. A processor-implemented method in a network device supporting candidate cells, the method comprising: A serving cell transmission to a user equipment (UE) may be activated for one or more Transport Configuration Indicator (TCI) states of the candidate cell, wherein the transmission occurs prior to a cell handover command for the UE to hand over from the serving cell to the candidate cell; Following the cell handover command, a random access procedure with the UE is executed. After the random access procedure is successfully completed, the candidate cell becomes the new serving cell; and After the random access procedure with the UE is successfully completed, communication with the UE is conducted using at least one of the one or more activated TCI states as one or more activated TCI states of the new serving cell. The communication occurs when the new serving cell does not transmit the activated TCI state to the UE.

[0136] Examples 1-6. A processor-implemented method according to Examples 1-5, wherein performing a random access procedure with the UE includes transmitting the timing advance (TA) value of the candidate cell to the UE.

[0137] Example 1-7. The method implemented by the processor according to Example 1-5 or 1-6 further includes: after the random access procedure with the UE is successfully completed, communicating with the UE using one of the one or more activated TCI states as the indication TCI state of the new serving cell. The communication occurs when the new serving cell does not transmit the indicated TCI state to the UE.

[0138] Examples 1-8. A processor-implemented method according to Examples 1-7, wherein one or more activated TCI states of the new serving cell include only the indicated TCI state of the new serving cell. Of the one or more activated TCI states that can be activated, TCI states other than the indicated TCI state are deactivated or not considered.

[0139] Example 2-1. A user equipment apparatus, comprising: Means for receiving from the serving cell the status of one or more activated Transport Configuration Indicators (TCIs) for a candidate cell. A component for receiving a cell handover command from the serving cell to the candidate cell, wherein the candidate cell is the target cell of the cell handover command; A component for performing a random access procedure with the target cell in response to the cell handover command, wherein the target cell becomes the new serving cell after the random access procedure is successfully completed; and A component for maintaining at least one of the one or more activated TCI states as one or more activated TCI states of the new serving cell after a successful completion of a random access procedure with the target cell.

[0140] Example 2-2. The user equipment apparatus according to Example 2-1 further includes: A component for responding to the cell handover command and determining that a timing advance (TA) value has not yet been provided for the target cell in the cell handover command; and A component for receiving the TA value of the target cell via the random access procedure.

[0141] Example 2-3. The user equipment apparatus according to Example 2-1 or 2-2 further includes: A component for receiving an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and A component for maintaining the indication of one TCI state as the indicated TCI state of the new serving cell after the random access procedure with the target cell has been successfully completed.

[0142] Example 2-4. The user equipment apparatus according to Example 2-3, wherein one or more activated TCI states of the new serving cell include only the indicated TCI state of the new serving cell. Among the one or more activated TCI states, TCI states other than the indicated TCI state are deactivated.

[0143] Example 2-5. The user equipment apparatus according to Example 2-1 or 2-2 further includes: A component for receiving an indication of one of the one or more activated TCI states in the cell handover command before performing a random access procedure with the target cell; and A component used to determine one of the following based on the cell handover command after a successful random access procedure with the target cell: Maintain at least one of the one or more activated TCI states, but do not maintain the indication of one of the TCI states. The indication of maintaining one of the TCI states is maintained, but the indication of one or more activated TCI states is not maintained, or Maintain at least one of the one or more activated TCI states, and maintain the indication of the one TCI state.

[0144] Example 2-6. The user equipment apparatus according to Example 2-1 or 2-2 further includes: A component for receiving an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and A component for determining, after a successful random access procedure with the target cell, not to maintain the indication of one TCI state as the indicated TCI state of the new serving cell.

[0145] Example 2-7. The user equipment apparatus according to Example 2-6, wherein the determination of the indication not to maintain the one TCI state is based on: The CORESET index value associated with the common search space (CSS) of at least one type of physical downlink control channel (PDCCH), and This includes a configuration for at least one field value corresponding to an indication that the TCI status is not applied. When the instructions are executed by the one or more processors, the user equipment device further causes the user equipment device to at least: based on the determination, and based on the reference signal selected for the random access procedure, apply a quasi-co-located (QCL) source to monitor at least one CSS on at least one CORESET.

[0146] Example 2-8. The user equipment apparatus according to Example 2-3, wherein the component for performing a random access procedure with the target cell includes: a component for selecting one of the SSBs or QCL source SSBs corresponding to an indicated TCI state if the corresponding signal synchronization block (SSB) or quasi-co-located (QCL) source SSB has a reference signal received power (RSRP) higher than a threshold.

[0147] Example 2-9. The user equipment apparatus according to any one of Examples 2-1 to 2-8 further comprises: Components for determining that a timing advance (TA) value was acquired before the cell handover command and that the cell handover command does not include a TA value; and Components used to determine, based on the determination, whether to trigger a random access procedure.

[0148] Example 2-10. The user equipment apparatus according to Example 2-1 further includes: Components that, in response to the cell handover command, determine that the timing advance (TA) value of the target cell has been acquired and determine one of the following: uplink resources have been configured for the target cell, or the scheduling of the uplink resources needs to be monitored; Components for transmitting uplink messages to the target cell using the uplink resources based on the determination; and The component used to determine whether the random access procedure is triggered before the uplink message is successfully transmitted to the target cell. The random access procedure is executed in response to the random access procedure being triggered.

[0149] Example 2-11. A user equipment apparatus according to Example 2-10, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: A component for receiving an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and A component for maintaining the indication of one TCI state as the indication TCI state of the new serving cell after the random access procedure with the target cell has been successfully completed.

[0150] Example 2-12. The user equipment apparatus according to Example 2-10 further includes: A component for receiving an indication of one of the one or more activated TCI states before performing a random access procedure with the target cell; and A component for determining, after a successful random access procedure with the target cell, not to maintain the indication of one TCI state as the indicated TCI state of the new serving cell.

[0151] Example 2-13. The user equipment apparatus according to Example 2-12, wherein the determination of the indication not to maintain the one TCI state is based on: The CORESET index value associated with the common search space (CSS) of at least one type of physical downlink control channel (PDCCH), and This includes a configuration for at least one field value corresponding to an indication that the TCI status is not applied. The user equipment apparatus further includes a component for monitoring at least one CSS on at least one CORESET by applying a quasi-co-located (QCL) source based on the determination and a reference signal selected for the random access procedure.

[0152] Example 2-14. A user equipment apparatus according to any one of Examples 2-1 to 2-13, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: A component for receiving, for each of a plurality of candidate cells, one or more corresponding activated Transport Configuration Indicator (TCI) states of the respective candidate cell from the serving cell. The plurality of candidate cells includes the candidate cells.

[0153] Example 2-15. A user equipment apparatus according to any one of Examples 2-1 to 2-14, wherein the cell handover command is a Layer 1 / Layer 2 triggered mobility (LTM) cell handover command.

[0154] Example 2-16. A processor-implemented method comprising: Receive one or more activated Transport Configuration Indicator (TCI) states for the candidate cell from the serving cell; Receive a cell handover command from the serving cell to the candidate cell, wherein the candidate cell is the target cell of the cell handover command; In response to the cell handover command, a random access procedure with the target cell is executed, and after the random access procedure is successfully completed, the target cell becomes the new serving cell; and After the random access procedure with the target cell is successfully completed, the one or more activated TCI states are maintained as the activated TCI states of the new serving cell.

[0155] Example 2-17. The processor implementation method according to Example 2-16 further includes: In response to the cell handover command, it is determined that a timing advance (TA) value has not yet been provided for the target cell in the cell handover command; and The TA value of the target cell is received via the random access procedure.

[0156] Example 2-18. The processor-implemented method according to Example 2-16 or 2-17 further includes: Before performing a random access procedure with the target cell, an indication of one of the one or more activated TCI states is received; and After the random access procedure with the target cell is successfully completed, the indication of the TCI state is maintained as the TCI state indicated by the new serving cell.

[0157] Example 2-19. A processor-implemented method according to Example 2-18, wherein one or more activated TCI states of the new serving cell include only the indicated TCI state of the new serving cell. Among the one or more activated TCI states, TCI states other than the indicated TCI state are deactivated or not considered.

[0158] Example 2-20. The processor-implemented method according to Example 2-16 or 2-17 further includes: Before performing a random access procedure with the target cell, an indication of one of the one or more activated TCI states is received; and After the random access procedure with the target cell is successfully completed, one of the following is determined based on the cell handover command: Maintain at least one of the one or more activated TCI states, but do not maintain the indication of one of the TCI states. The indication of maintaining one of the TCI states is maintained, but the indication of one or more activated TCI states is not maintained, or Maintain at least one of the one or more activated TCI states, and maintain the indication of the one TCI state.

[0159] Example 2-21. The processor-implemented method according to Example 2-16 or 2-17 further includes: Before performing a random access procedure with the target cell, an indication of one of the one or more activated TCI states is received; and After the random access procedure with the target cell is successfully completed, it is determined that the indication of the one TCI state will not be maintained as the TCI state indicated by the new serving cell.

[0160] Example 2-22. A processor implementation method according to Example 2-21, wherein the determination of an indication not to maintain the one TCI state is based on: The CORESET index value associated with the common search space (CSS) of at least one type of physical downlink control channel (PDCCH), and This includes a configuration for at least one field value corresponding to an indication that the TCI status is not applied. The method further includes: based on the determination, and based on the reference signal selected for the random access procedure, applying a quasi-co-located (QCL) source to monitor at least one CSS on at least one CORESET.

[0161] Example 2-23. A processor-implemented method according to Example 2-18, wherein performing a random access procedure with the target cell includes: if the corresponding Signal Synchronization Block (SSB) or Quasi-Co-location (QCL) source SSB has a reference signal received power (RSRP) higher than a threshold, then selecting one of the SSB or QCL source SSBs corresponding to an indicated TCI state.

[0162] Example 2-24. The method implemented by the processor according to any one of Examples 2-16 to 2-23 further includes: It is determined that a timing advance (TA) value was acquired before the cell handover command and that the cell handover command does not include the TA value; and Based on the determination, it is decided to trigger a random access procedure.

[0163] Example 2-25. The processor-implemented method according to Example 2-16 further includes: In response to the cell handover command, it is determined that the timing advance (TA) value of the target cell has been obtained and one of the following is determined: uplink resources have been configured for the target cell, or the scheduling of the uplink resources needs to be monitored; Based on the determination, uplink messages are transmitted to the target cell using the uplink resources; and It is determined that the random access procedure was triggered before the uplink message was successfully transmitted to the target cell. The random access procedure is executed in response to the random access procedure being triggered.

[0164] Example 2-26. The processor-implemented method according to Example 2-25 further includes: Before performing a random access procedure with the target cell, an indication of one of the one or more activated TCI states is received; and After the random access procedure with the target cell is successfully completed, the indication of the TCI state is maintained as the indication TCI state of the new serving cell.

[0165] Example 2-27. The processor implementation method according to Example 2-25 further includes: Before performing a random access procedure with the target cell, an indication of one of the one or more activated TCI states is received; and After the random access procedure with the target cell is successfully completed, it is determined that the indication of the one TCI state will not be maintained as the indication TCI state of the new serving cell.

[0166] Example 2-28. A processor implementation method according to Example 2-27, wherein the determination of an indication not to maintain the one TCI state is based on: The CORESET index value associated with the common search space (CSS) of at least one type of physical downlink control channel (PDCCH), and This includes a configuration for at least one field value corresponding to an indication that the TCI status is not applied. The method further includes: based on the determination, and based on the reference signal selected for the random access procedure, applying a quasi-co-located (QCL) source to monitor at least one CSS on at least one CORESET.

[0167] Example 2-29. The method implemented by the processor according to any one of Examples 2-16 to 2-28 further includes: For each candidate cell among a plurality of candidate cells, receive one or more corresponding active Transport Configuration Indicator (TCI) states for the corresponding candidate cell from the serving cell. The plurality of candidate cells includes the candidate cells.

[0168] Example 2-30. A method implemented by a processor according to any one of Examples 2-16 to 2-29, wherein the cell handover command is a Layer 1 / Layer 2 triggered mobility (LTM) cell handover command.

[0169] The embodiments and aspects disclosed herein are examples of this disclosure and may be embodied in various forms. For example, although some embodiments herein are described as separate embodiments, each embodiment herein may be combined with one or more other embodiments herein. The specific structural and functional details disclosed herein should not be construed as limiting, but should serve as the basis for the claims and as a representative basis for teaching those skilled in the art to apply this disclosure in various aspects of virtually any suitable detailed structure. Throughout the description of the drawings, the same reference numerals may refer to similar or identical elements.

[0170] The phrases “in one aspect,” “in multiple aspects,” “in all aspects,” “in some aspects,” or “in other aspects” may each refer to one or more of the same or different aspects according to this disclosure. The phrase “multiple aspects” may refer to two or more.

[0171] The phrases “in one embodiment,” “in multiple embodiments,” “in various embodiments,” “in some embodiments,” or “in other embodiments” may each refer to one or more of the same or different embodiments according to this disclosure. The phrase “A or B” means “(A), (B), or (A and B).” The phrase “at least one of A, B, or C” means “(A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C).”

[0172] Any method, program, algorithm, or code described herein can be converted into or expressed in a programming language or computer program. As used herein, the terms "programming language" and "computer program" each include any language used to specify instructions to a computer, and include (but are not limited to) the following languages ​​and their derivatives: assembly language, 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, meta-languages ​​used to specify the program itself, and all first-, second-, third-, fourth-, fifth-, or higher generation computer languages. Databases and other data schemas, and any other meta-languages, are also included. No distinction is made between interpreted, compiled, or both compiled and interpreted languages. No distinction is made between compiled and source code versions of a program. Therefore, a reference to a program (if the programming language may exist in more than one state, such as source code state, compiled state, object code state, or linked state) is a reference to any and all such states. References to a program may cover the actual instructions and / or the intent of those instructions.

[0173] Although various aspects of this disclosure have been shown in the accompanying drawings, this is not intended to limit the disclosure thereto, as the disclosure is intended to extend its scope to the widest extent permitted by the art to which it pertains, and the specification should be interpreted accordingly. Therefore, the foregoing description should not be construed as restrictive, but rather as exemplary illustration of particular aspects. Other modifications will be contemplated by those skilled in the art within the scope and spirit of the appended claims.

Claims

1. A user equipment apparatus, comprising: One or more processors; as well as At least one memory storing instructions that, when executed by the one or more processors, cause the user equipment device to at least: Receive one or more activated Transport Configuration Indicator (TCI) states for the candidate cell from the serving cell; Receive a cell handover command from the serving cell to the candidate cell, wherein the candidate cell is the target cell of the cell handover command; In response to the cell handover command, a random access procedure with the target cell is executed, and after the random access procedure is successfully completed, the target cell becomes the new serving cell; as well as After the random access procedure with the target cell is successfully completed, at least one of the one or more activated TCI states is maintained as one or more activated TCI states of the new serving cell.

2. The user equipment apparatus of claim 1, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: In response to the cell handover command, it is determined that a timing advance (TA) value has not yet been provided for the target cell in the cell handover command; and The TA value of the target cell is received via the random access procedure.

3. The user equipment apparatus of claim 2, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: Before performing a random access procedure with the target cell, an indication of one of the one or more activated TCI states is received; and After the random access procedure with the target cell is successfully completed, the indication of the TCI state is maintained as the TCI state indicated by the new serving cell.

4. The user equipment apparatus of claim 3, wherein the one or more activated TCI states of the new serving cell include only the indicated TCI state of the new serving cell. Among the one or more activated TCI states, TCI states other than the indicated TCI state are deactivated.

5. The user equipment apparatus of claim 2, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: Before performing the random access procedure with the target cell, the cell handover command receives an indication of one of the one or more activated TCI states; and After the random access procedure with the target cell is successfully completed, one of the following is determined based on the cell handover command: Maintain at least one of the one or more activated TCI states, but do not maintain the indication of one of the TCI states. The indication of maintaining one of the TCI states is maintained, but the indication of one or more activated TCI states is not maintained, or Maintain at least one of the one or more activated TCI states, and maintain the indication of the one TCI state.

6. The user equipment apparatus of claim 2, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: Before performing a random access procedure with the target cell, an indication of one of the one or more activated TCI states is received; and After the random access procedure with the target cell is successfully completed, it is determined that the indication of the one TCI state will not be maintained as the TCI state indicated by the new serving cell.

7. The user equipment apparatus of claim 6, wherein the determination of the indication of not maintaining the one TCI state is based on: The CORESET index value associated with the common search space (CSS) of at least one type of physical downlink control channel (PDCCH), and This includes a configuration for at least one field value corresponding to an indication that the TCI status is not applied. When the instructions are executed by the one or more processors, the user equipment device further causes the user equipment device to at least: based on the determination, and based on the reference signal selected for the random access procedure, apply a quasi-co-located (QCL) source to monitor at least one CSS on at least one CORESET.

8. The user equipment apparatus of claim 3, wherein, during the execution of a random access procedure with the target cell, the instruction, when executed by the one or more processors, causes the user equipment apparatus to at least: select one of the SSBs or QCL source SSBs corresponding to an indicated TCI state if the corresponding Signal Synchronization Block (SSB) or Quasi-Co-located (QCL) source SSB has a reference signal received power (RSRP) higher than a threshold.

9. The user equipment apparatus of claim 1, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: It is determined that a timing advance (TA) value was acquired before the cell handover command and that the cell handover command does not include the TA value; and Based on the determination, it is decided to trigger a random access procedure.

10. The user equipment apparatus of claim 1, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: In response to the cell handover command, it is determined that the timing advance (TA) value of the target cell has been obtained and one of the following is determined: uplink resources have been configured for the target cell, or the scheduling of the uplink resources needs to be monitored; Based on the determination, the uplink resources are used to transmit uplink messages to the target cell; as well as It is determined that the random access procedure was triggered before the uplink message was successfully transmitted to the target cell. The random access procedure is executed in response to the random access procedure being triggered.

11. The user equipment apparatus of claim 10, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: Before performing a random access procedure with the target cell, an indication of one of the one or more activated TCI states is received; and After the random access procedure with the target cell is successfully completed, the indication of the TCI state is maintained as the TCI state indicated by the new serving cell.

12. The user equipment apparatus of claim 10, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: Before performing a random access procedure with the target cell, an indication of one of the one or more activated TCI states is received; and After the random access procedure with the target cell is successfully completed, it is determined that the indication of the one TCI state will not be maintained as the TCI state indicated by the new serving cell.

13. The user equipment apparatus of claim 12, wherein the determination of the indication of not maintaining the one TCI state is based on: The CORESET index value associated with the common search space (CSS) of at least one type of physical downlink control channel (PDCCH), and This includes a configuration for at least one field value corresponding to an indication that the TCI status is not applied. When the instructions are executed by the one or more processors, the user equipment device further causes the user equipment device to at least: based on the determination, and based on the reference signal selected for the random access procedure, apply a quasi-co-located (QCL) source to monitor at least one CSS on at least one CORESET.

14. The user equipment apparatus of claim 1, wherein the instructions, when executed by the one or more processors, further cause the user equipment apparatus to at least: For each of the multiple candidate cells, receive one or more corresponding activated Transport Configuration Indicator (TCI) states from the serving cell for the respective candidate cell. The plurality of candidate cells includes the candidate cells.

15. The user equipment apparatus according to claim 1, wherein the cell handover command is a Layer 1 / Layer 2 triggered mobility (LTM) cell handover command.

16. A processor-implemented method, comprising: Receive one or more activated Transport Configuration Indicator (TCI) states for the candidate cell from the serving cell; Receive a cell handover command from the serving cell to the candidate cell, wherein the candidate cell is the target cell of the cell handover command; In response to the cell handover command, a random access procedure with the target cell is executed, and after the random access procedure is successfully completed, the target cell becomes the new serving cell; as well as After the random access procedure with the target cell is successfully completed, the one or more activated TCI states are maintained as the activated TCI states of the new serving cell.

17. The processor-implemented method according to claim 16, further comprising: In response to the cell handover command, it is determined that a timing advance (TA) value has not yet been provided for the target cell in the cell handover command; as well as The TA value of the target cell is received via the random access procedure.

18. The processor-implemented method according to claim 17, further comprising: Before performing a random access procedure with the target cell, receive an indication of one of the one or more activated TCI states; as well as After the random access procedure with the target cell is successfully completed, the indication of the TCI state is maintained as the TCI state indicated by the new serving cell.

19. The processor-implemented method of claim 18, wherein the one or more activated TCI states of the new serving cell include only the indicated TCI state of the new serving cell. Among the one or more activated TCI states, TCI states other than the indicated TCI state are deactivated or not considered.

20. The processor-implemented method according to claim 17, further comprising: Before performing a random access procedure with the target cell, receive an indication of one of the one or more activated TCI states; as well as After the random access procedure with the target cell is successfully completed, one of the following is determined based on the cell handover command: Maintain at least one of the one or more activated TCI states, but do not maintain the indication of one of the TCI states. The indication of maintaining one of the TCI states is maintained, but the indication of one or more activated TCI states is not maintained, or Maintain at least one of the one or more activated TCI states, and maintain the indication of the one TCI state.

21. The processor-implemented method according to claim 17, further comprising: Before performing a random access procedure with the target cell, receive an indication of one of the one or more activated TCI states; as well as After the random access procedure with the target cell is successfully completed, it is determined that the indication of the one TCI state will not be maintained as the TCI state indicated by the new serving cell.

22. The processor-implemented method of claim 21, wherein the determination of the indication not to maintain the one TCI state is based on: The CORESET index value associated with the common search space (CSS) of at least one type of physical downlink control channel (PDCCH), and This includes a configuration for at least one field value corresponding to an indication that the TCI status is not applied. The method further includes: Based on the determination, and based on the reference signal selected for the random access procedure, a quasi-co-located (QCL) source is applied to monitor at least one CSS on at least one CORESET.

23. The processor-implemented method of claim 18, wherein performing the random access procedure with the target cell comprises: If the corresponding Signal Synchronization Block (SSB) or Quasi-Co-located (QCL) source SSB has a reference signal received power (RSRP) higher than the threshold, then one of the SSBs or QCL source SSBs corresponding to an indicated TCI state is selected.

24. The processor-implemented method according to claim 16, further comprising: It is determined that a timing advance (TA) value was acquired before the cell handover command and that the cell handover command does not include the TA value; as well as Based on the determination, it is decided to trigger a random access procedure.

25. The processor-implemented method according to claim 16, further comprising: In response to the cell handover command, it is determined that the timing advance (TA) value of the target cell has been obtained and one of the following is determined: uplink resources have been configured for the target cell, or the scheduling of the uplink resources needs to be monitored; Based on the determination, the uplink resources are used to transmit uplink messages to the target cell; as well as It is determined that the random access procedure was triggered before the uplink message was successfully transmitted to the target cell. The random access procedure is executed in response to the random access procedure being triggered.

26. The processor-implemented method according to claim 25, further comprising: Before performing a random access procedure with the target cell, receive an indication of one of the one or more activated TCI states; as well as After the random access procedure with the target cell is successfully completed, the indication of the TCI state is maintained as the TCI state indicated by the new serving cell.

27. The processor-implemented method according to claim 25, further comprising: Before performing a random access procedure with the target cell, receive an indication of one of the one or more activated TCI states; as well as After the random access procedure with the target cell is successfully completed, it is determined that the indication of the one TCI state will not be maintained as the TCI state indicated by the new serving cell.

28. The processor-implemented method of claim 27, wherein the determination of the indication of not maintaining the one TCI state is based on: The CORESET index value associated with the common search space (CSS) of at least one type of physical downlink control channel (PDCCH), and This includes a configuration for at least one field value corresponding to an indication that the TCI status is not applied. The method further includes: Based on the determination, and based on the reference signal selected for the random access procedure, a quasi-co-located (QCL) source is applied to monitor at least one CSS on at least one CORESET.

29. The processor-implemented method according to claim 16, further comprising: For each of the multiple candidate cells, receive one or more corresponding activated Transport Configuration Indicator (TCI) states from the serving cell for the respective candidate cell. The plurality of candidate cells includes the candidate cells.

30. The processor-implemented method of claim 16, wherein the cell handover command is a Layer 1 / Layer 2 triggered mobility (LTM) cell handover command.

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