Cell switch transmission configuration indicator (TCI) status

Abstract

The user device includes a processor and at least one memory. The memory stores instructions that, when executed by the processor, cause the user device to receive at least one or more activated transmission configuration indicator (TCI) states of a candidate cell from a serving cell; receive a cell switch command from the serving cell to switch from the serving cell to a candidate cell, wherein the candidate cell is the target cell of the cell switch command; execute a random access procedure by the target cell in response to the cell switch command, wherein after the random access procedure is successfully completed, the target cell becomes the new serving cell; and after the random access procedure by the target cell is successfully completed, maintain at least one of the one or more activated TCI states as the one or more activated TCI states of the new serving cell.

Description

Technical Field

[0001] Various exemplary embodiments generally relate to wireless networks, and more particularly, to transmission configuration indicator (TCI) states for mobility in wireless networks.

Background Art

[0002] Wireless networks bring great advantages to user mobility. The ability to maintain a connection even when the user is moving not only benefits the user himself / herself, but also improves the efficiency and productivity of society as a whole. As user expectations for connection reliability, data speed, and device battery life increase, wireless network technology must also keep up with such expectations. Therefore, the interest in improving wireless network technology continues. For that purpose, cell switching in various protocol layers has been developed in mobile phone standards, and conventional layer 3 handovers have existed for several generations. Furthermore, conditional handovers have been introduced to improve the reliability of handovers. In recent developments, lower layer handovers known as layer 1 / layer 2 triggered mobility (LTM) are being considered.

Summary of the Invention

[0003] According to an aspect of the present disclosure, a user equipment device includes one or more processors and at least one memory. When executed by the one or more processors, the at least one memory causes the user equipment device to at least

[0004] In some aspects of the present disclosure, a user device includes one or more processors and at least one memory for storing instructions. When an instruction is executed by one or more processors, it causes the user device to at least receive from a serving cell one or more activated transmission configuration indicator (TCI) states of a candidate cell; receive from a serving cell a cell switch command to switch from a serving cell to a candidate cell, wherein the candidate cell is the target cell of the cell switch command; perform a random access procedure by the target cell in response to the cell switch command, wherein after the random access procedure is successfully completed, the target cell becomes the new serving cell; and after the random access procedure by the target cell is successfully completed, maintain at least one of the one or more activated TCI states as the one or more activated TCI states of the new serving cell.

[0005] In one embodiment of the user device, when an instruction is executed by one or more processors, the user device may further perform, in response to a cell switch command, the determination that no timing advance (TA) value has been provided to the target cell in the cell switch command, and the reception of the target cell's TA value via a random access procedure.

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

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

[0008] In one embodiment of the user device, when an instruction is executed by one or more processors, the user device may further perform, at least, in a cell switch command, an indication of one of the one or more activated TCI states in order to perform a random access procedure by the target cell, and after the random access procedure by the target cell is successfully completed, determine, based on the cell switch command, one of the following: maintain at least one of the one or more activated TCI states but not maintain an indication of one TCI state, maintain an indication of one TCI state but not maintain one or more activated TCI states, or maintain at least one of the one or more activated TCI states and maintain an indication of one TCI state.

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

[0010] In one embodiment of the user equipment, the decision not to maintain an indication of a single TCI state may be based on the fact that the CORESET index value is associated with at least one physical downlink control channel (PDCCH) common search space (CSS), and that a configuration having at least one field value corresponds to not applying an indication of a single TCI state. When the instruction is executed by one or more processors, the user equipment may be further prompted to apply at least a quasi-coexistence (QCL) source to monitor at least one CSS on at least one CORESET based on the decision and a reference signal selected for a random access procedure.

[0011] In one embodiment of a user device, when executing a random access procedure by a target cell, if an instruction is executed by one or more processors, the user device may be prompted to select one of the SSBs or QCL source SSBs corresponding to one of the indicated TCI states, provided that each signal synchronization block (SSB) or quasi-co-located (QCL) source SSB has a reference signal reception power (RSRP) that exceeds a threshold.

[0012] In one embodiment of the user device, when an instruction is executed by one or more processors, the user device may further determine that a timing advance (TA) value is obtained before the cell switch command and that the cell switch command does not include a TA value, and that, based on this determination, a random access procedure is triggered.

[0013] In one embodiment of the user device, when executed by one or more processors, an instruction can be used to cause the user device to at least determine, in response to a cell switch command, that a timing advance (TA) value for a target cell has been obtained and that an uplink resource has been configured for the target cell or that the scheduling of an uplink resource will be monitored; to transmit an uplink message to the target cell using the uplink resource based on the determination; and to determine that a random access procedure was triggered before the uplink message was successfully transmitted to the target cell, and that the random access procedure is executed in response to the triggering of the random access procedure.

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

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

[0016] In one embodiment of the user device, when an instruction is executed by one or more processors, the user device can be further caused to receive, at least, from a serving cell, one or more activated transmission configuration indicator (TCI) states of each candidate cell for each of a plurality of candidate cells, wherein the plurality of candidate cells include candidate cells.

[0017] In some user equipment configurations, the cell switch command may be a Layer 1 / Layer 2 triggered mobility (LTM) cell switch command.

[0018] According to aspects of the present disclosure, a processor implementation method includes the steps of: receiving one or more activated transmission configuration indicator (TCI) states of a candidate cell from a serving cell; receiving a cell switch command from the serving cell to switch from the serving cell to a candidate cell, wherein the candidate cell is the target cell of the cell switch command; performing a random access procedure by the target cell in response to the cell switch command, wherein the target cell becomes a new serving cell after the random access procedure is successfully completed; and maintaining one or more activated TCI states as the activated TCI states of the new serving cell after the random access procedure by the target cell is successfully completed.

[0019] In one embodiment of the processor implementation, the method may further include, in response to a cell switch command, determining that no timing advance (TA) value has been provided to the target cell in the cell switch command, and receiving the TA value of the target cell via a random access procedure.

[0020] In one embodiment of the processor implementation, the method may further include the steps of receiving an indication of one of one or more activated TCI states before performing a random access procedure by the target cell, and after the random access procedure by the target cell has been successfully completed, maintaining the indication of one TCI state as the indicated TCI state of the new serving cell.

[0021] In one embodiment of the processor implementation, one or more activated TCI states of a new serving cell may include only the indicated TCI states of the new serving cell, and any TCI states other than the indicated TCI states among the one or more activated TCI states are deactivated or not considered.

[0022] In one embodiment of the processor implementation, the method may further include the steps of: receiving an indication of one of one or more activated TCI states before performing a random access procedure by the target cell; and, after the random access procedure by the target cell has successfully completed, determining, based on a cell switch command, one of the following: retaining at least one of the one or more activated TCI states but not retaining an indication of one TCI state; retaining an indication of one TCI state but not retaining one or more activated TCI states; or retaining at least one of the one or more activated TCI states and retaining an indication of one TCI state.

[0023] In one embodiment of the processor implementation, the method may further include the steps of receiving an indication of one of one or more activated TCI states before performing a random access procedure by the target cell, and after the random access procedure by the target cell has successfully completed, deciding not to retain the indication of one TCI state as an indicated TCI state of the new serving cell.

[0024] In one embodiment of the processor implementation, the decision not to maintain an indication of a single TCI state may be based on the fact that a CORESET index value is associated with at least one physical downlink control channel (PDCCH) common search space (CSS), and that a configuration having at least one field value corresponds to not applying an indication of a single TCI state. Based on the decision, the method further includes the step of applying a quasi-coexistence (QCL) source to monitor at least one CSS on at least one CORESET based on a reference signal selected for a random access procedure.

[0025] In one embodiment of the processor implementation, the step of performing a random access procedure by a target cell may include the step of selecting one of the SSBs or QCL source SSBs corresponding to one indicated TCI state if each signal-synchronized block (SSB) or quasi-coexistence (QCL) source SSB has a reference signal received power (RSRP) that exceeds a threshold.

[0026] In one embodiment of the processor implementation, the method may further include the steps of obtaining a timing advance (TA) value before a cell switch command and determining that the cell switch command does not include a TA value, and determining, based on the determination, that a random access procedure is triggered.

[0027] In one aspect of the processor implementation method, the method includes: in response to a cell switch command, determining that the timing advance (TA) value of the target cell has been obtained and whether uplink resources have been configured for the target cell or the scheduling of uplink resources will be monitored; based on the determination, transmitting an uplink message to the target cell using the uplink resources; and determining that a random access procedure has been triggered before the uplink message is 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 implementation method, the method may further include receiving an indication of one TCI state among one or more activated TCI states before executing the random access procedure by the target cell, and maintaining the indication of one TCI state as the indicated TCI state of the new serving cell after the random access procedure by the target cell has been successfully completed.

[0029] In one aspect of the processor implementation method, the method may further include receiving an indication of one TCI state among one or more activated TCI states before executing the random access procedure by the target cell, and determining not to maintain the indication of one TCI state as the indicated TCI state of the new serving cell after the random access procedure by the target cell has been successfully completed.

[0030] In one aspect of the processor implementation method, the method may further include receiving, from the serving cell, for each candidate cell of a plurality of candidate cells, one or more activated transmission configuration indicator (TCI) states of each respective candidate cell, wherein the plurality of candidate cells includes the candidate cells.

[0031] In one aspect of the processor implementation method, the cell switch command may be a layer 1 / layer 2 triggered mobility (LTM) cell switch command.

[0032] According to some aspects, the subject matter of the independent claims is provided. Some further aspects are defined in the dependent claims.

[0033] Next, some exemplary embodiments will be described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] [Figure 1] FIG. is a diagram illustrating an exemplary embodiment of a wireless network between a network system and a user equipment device (UE) according to one exemplary aspect of the present disclosure. [Figure 2] FIG. is a diagram illustrating an exemplary embodiment of transmission and reception beams for a wireless network between a network device and a user equipment device (UE) according to one exemplary aspect of the present disclosure. [Figure 3] FIG. is a diagram illustrating an exemplary embodiment of a UE that sweeps a reception beam of a synchronization signal block (SSB) burst according to one exemplary aspect of the present disclosure. [Figure 4] FIG. is a diagram illustrating an exemplary embodiment of a layer 1 / layer 2 triggered mobility (LTM) scenario according to one exemplary aspect of the present disclosure. [Figure 5] FIG. is a diagram illustrating an exemplary embodiment of a contention-based random access procedure according to one exemplary aspect of the present disclosure. [Figure 6A] FIG. is a diagram illustrating an exemplary embodiment of signals and operations among a UE, a central unit (CU), a source distributed unit (DU), and a target DU related to LTM according to one exemplary aspect of the present disclosure. [Figure 6B]This figure shows an exemplary embodiment of signaling and operation between a UE, a central unit (CU), a source distribution unit (DU), and a target DU related to LTM, according to one exemplary aspect of the present disclosure. [Figure 7] This figure shows an exemplary embodiment of the signaling and operation between the UE, source cell, and target cell, relating to the state of the transmission configuration indicator (TCI) before, during, and after the cell switch, according to one exemplary aspect of the present disclosure. [Figure 8] This figure shows an exemplary embodiment of signaling and operation between a UE, source cell, and target cell in a cell switch scenario without timing advance (TA) values, according to one exemplary aspect of the present disclosure. [Figure 9] This figure shows an exemplary embodiment of signaling and operation between a UE, a source cell, and a target cell in a cell switch scenario with a timing advance (TA) value, according to one exemplary aspect of the present disclosure. [Figure 10] This is an exemplary operation flowchart of a UE for a cell switch according to one exemplary aspect of the present disclosure. [Figure 11] This is an exemplary flowchart of the operation of a network device for a cell switch, according to one exemplary aspect of the present disclosure. [Figure 12] This figure shows an exemplary embodiment of a component of a UE or network device according to one exemplary aspect of the present disclosure. [Modes for carrying out the invention]

[0035] The following description includes certain details to provide a complete understanding of the disclosed embodiments. However, those skilled in the art will recognize that the embodiments can be practiced without one or more of these specific details, or using other methods, components, materials, etc. In other examples, well-known structures associated with transmitters, receivers, or transceivers are not shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0036] Throughout this specification, any reference to “one aspect” or “an aspect” means that the particular feature, structure, or characteristic described in relation to that aspect is included in at least one aspect. Therefore, the occurrences of the phrase “in one aspect” or “in an aspect” in various places throughout this specification do not necessarily all refer to the same aspect. Furthermore, the particular feature, structure, or characteristic can be combined in any suitable way in one or more aspects.

[0037] The embodiments described herein, but not limited to, may be implemented in wireless network equipment such as devices utilizing other wireless network systems, including Worldwide Interoperability for Microwave Access (WiMAX), Global Systems for Mobile Communications (GSM, 2G), GSM Edge Radio Access Network (GERAN), General Purpose Packet Radio Services (GRPS), Universal Mobile Telecommunications Systems (UMTS, 3G) based on Basic Broadband Code Division Multiple Access (W-CDMA), High-Speed ​​Packet Access (HSPA), Long-Term Evolution (LTE), LTE-Advanced, Enhanced LTE (eLTE), 5G New Radio (5G NR), 5G Advanced, 6G (and later), and 802.11ax (Wi-Fi 6). The term “eLTE” as used herein refers to an evolved form of LTE connected to a 5G core. LTE is also known as Evolved UMTS Terrestrial Radio Access (EUTRA) or Evolved UMTS Terrestrial Radio Access Network (EUTRAN).

[0038] Because UEs may move from one area to another, handover or mobility procedures can be crucial to support continuous communication (uninterrupted or with minimal interruption) between the UE and the network. For example, a UE might be configured to monitor specific reference signals from one or more network devices (e.g., SSB, Channel Status Information Reference Signal (CSI-RS), DL Reference Signal (RS)), perform signal measurements of the reference signals, and report those measurements to the network so that a decision can be made to hand over the UE to an adjacent cell (e.g., if signal quality degradation is detected). The handover is typically initiated by the network. In the case of 5G NR, the handover is initiated or a handover command may be signaled via higher-layer signaling, such as Layer 3 or Radio Resource Control (RRC) signaling. Higher-layer signaling can involve the network and therefore can have high latency. In various situations, a UE can benefit from more efficient handover procedures triggered via lower-layer signaling, such as L1 / L2 signaling, which has lower latency than higher-layer signaling. Handovers triggered via lower-layer signaling as used herein are sometimes referred to as lower-layer triggered mobility (LTM). In some cases, candidate cells for LTM are sometimes referred to as LTM candidate cells.

[0039] As used herein, the term “cell switch” means and refers to any change in a cell, regardless of whether the change is triggered via Layer 1 signaling, Layer 2 signaling, and / or Layer 3 signaling, and / or other signaling. A cell switch may be for a terminal device in RRC connection mode, and therefore a cell switch may include bidirectional signaling between the terminal device and at least one network node of the radio access network, typically at least between the source and target network nodes of the cell switch. While this disclosure primarily uses LTM as an example of a cell switch, this disclosure is intended and understood to be able to operate with Layer 3 handover or any cell switch.

[0040] In this disclosure, the term “serving cell” may be used to refer to a network node or network device (or part thereof) that provides services to a UE; the term “candidate cell” may be used to refer to a network node or network device (or part thereof) that is a potential target of a cell switch command; and the term “target cell” may be used to refer to a network node or network device (or part thereof) that is the target of a cell switch command. In some examples, the LTM target may be a serving cell (for example, the target may be a “SCell,” i.e., a secondary cell in carrier aggregation).

[0041] As used herein, the terms “transmit towards,” “receive from,” and “cooperate with” (and their variations) include communications that may or may not include communications through one or more intermediate devices or nodes. The term “acquire” (and its variations) includes acquisition in the first instance or reacquisition after the first instance. The term “connection” may mean a physical or logical connection.

[0042] Aspects of this disclosure provide that a UE maintains the activated TCI state of a target cell before a cell switch command from the UE switches from its serving cell to the target cell, and further provides that after the cell switch to the target cell as the new serving cell, the UE maintains such activated TCI state as the activated TCI state of the new serving cell. In embodiments, the UE also maintains the indicated TCI state of the target cell provided before the cell switch as the indicated TCI state of the new serving cell. The advantages of such embodiments include reducing or eliminating delays in preparing for data communication after the UE and the target cell have successfully completed a random access procedure, and improving the utilization of time and resources in the UE and the new serving cell.

[0043] Figure 1 shows an example of a wireless network between a network system 100 and a user equipment (UE) 150. The network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network devices 130 (e.g., test equipment). The network nodes 120 are described in more detail below. As used herein, the term “network apparatus” may refer to any component of the network system 100, such as the servers 110, the network nodes 120, the network devices 130, any of the aforementioned components, and / or any other arbitrary components of the network system 100. Examples of network apparatus include, but are not limited to, apparatus implementing embodiments of 5G NR. This disclosure describes embodiments related to 5G NR and embodiments with embodiments defined by the Third Generation Partnership Project (3GPP). However, embodiments relating to other wireless network technologies are also considered to be included within the scope of this disclosure.

[0044] The following description provides further details on an example of a network node. In a 5G NR network, a gNodeB (also known as a gNB) may include a node that provides NR user plane and control plane protocol termination to the UE, for example, according to 3GPP TS38.300 V16.6.0 (2021-06) Section 3.2, and is connected to the 5G core (5GC) via an NG interface, which is incorporated herein by reference.

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

[0046] Layer 2 (L2) of NR is divided into sublayers of Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and Service Data Adaptation Protocol (SDAP), as follows: The physical layer provides a transport channel to the MAC sublayer. The MAC sublayer provides logical channels to the RLC sublayer. The RLC sublayer provides RLC channels to the PDCP sublayer. The PDCP sublayer provides wireless bearers to the SDAP sublayer. The SDAP sublayer provides quality of service (QoS) flow to the 5GC. The control channel includes the broadcast control channel (BCCH) and the physical control channel (PCCH).

[0047] Layer 3 (L3) includes, for example, Radio Resource Control (RRC) according to Section 6 of 3GPP TS38.300 V16.6.0 (2021-06), which is incorporated herein by reference.

[0048] The gNB Central Unit (gNB-CU) includes, for example, a logical node, which hosts the gNB's Radio Resource Control (RRC), Service Data Adaptive Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) protocols, or the en-gNB's RRC and PDCP protocols, and controls the operation of one or more gNB Distributed Units (gNB-DUs). The gNB-CU terminates the F1 interface connected to the gNB-DUs. The gNB-CU may also be referred to herein as the CU, Central Unit, Central 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 a gNB or en-gNB, and whose operation is partially controlled by a gNB-CU. A single gNB-DU supports one or more cells. A single cell is supported by only one gNB-DU. A gNB-DU terminates an F1 interface connected to a gNB-CU. A gNB-DU may also be referred to as a DU or distributed unit in this specification.

[0050] As used herein, the term “network node” may refer to a gNB, gNB-CU, or gNB-DU, or a combination thereof. A RAN (Radio Access Network) node or network node, such as a gNB, gNB-CU, gNB-DU, or a part thereof, may be implemented using an apparatus comprising, for example, at least one processor and / or at least one memory with processor-readable instructions ("programs") configured to support and / or provide and / or process CU and / or DU-related functions and / or features, and / or at least one protocol (sub)layer of the RAN (Radio Access Network), such as layer 2 and / or layer 3. Various functional partitions are possible between central and distributed units. Examples of such apparatus and components are described below in reference to Figure 12.

[0051] The gNB-CU portion and the gNB-DU portion may be located in the same place, for example, or they may be physically separated. The gNB-DU may be further divided into, for example, two parts, one of which may include processing equipment and the other may include an antenna. The central unit (CU) may also be referred to as BBU / REC / RCC / C-RAN / V-RAN, O-RAN, or a part thereof. The distributed unit (DU) may also be referred to as RRH / RRU / RE / RU, or a part thereof. Hereinafter, in various exemplary embodiments of this disclosure, a network node supporting central unit functionality or at least one of the Layer 3 protocols of a radio access network may be, for example, a gNB-CU. Similarly, a network node supporting distributed unit functionality or at least one of the Layer 2 protocols of a radio access network may be, for example, a gNB-DU.

[0052] A gNB-CU may support one or more gNB-DUs. Since a gNB-DU may support one or more cells, it can support serving cells for user equipment (UEs) or candidate cells for handover, dual connectivity, and / or carrier aggregation in other procedures.

[0053] The user equipment (UE) 150 may include, among other types of user equipment, wireless or mobile devices, devices with a radio interface for interacting with a RAN (Radio Access Network), smartphones, in-vehicle devices, IoT devices, or M2M devices. Such a UE 150 may include at least one processor and at least one memory containing program code, and the at least one memory and computer program code are configured by the at least one processor to cause the device to perform at least certain operations, such as an RRC connection to a RAN. An example of the components of the UE is described with reference to Figure 12. In an embodiment, the UE 150 may be configured to generate messages (e.g., including a cell ID) to be transmitted wirelessly toward a RAN (e.g., to reach a serving cell and communicate). In an embodiment, the 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 procedures that the UE may perform.

[0054] Continuing 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 gNBs of the 5G NR network, or it may include any other devices configured to control radio communications and manage radio resources within cells. The term “resource” as used herein may refer to radio resources such as resource blocks (RBs), physical resource blocks (PRBs), radio frames, subframes, time slots, subbands, frequency domains, subcarriers, and beams. In embodiments, network node 120 may be referred to as a base station.

[0055] Figure 1 provides an example of a network system 100 and UE 150 and is for illustrative purposes only. Those skilled in the art will understand that the network system 100 includes components not shown in Figure 1, and that other user equipment may communicate with the network system 100.

[0056] Figure 2 shows an exemplary embodiment of a wireless network between a network device 210 and a user equipment (UE) 150. The network device 210 is configured to form beams 220 in multiple directions, and the UE 150 is also configured to form beams 260 in multiple directions. As those skilled in the art will understand, the ability to beamform in multiple directions can be achieved using an arrangement of multiple radiating elements, sometimes called an "array" of radiating elements. Beamforming (also known as spatial filtering) enables the transmission or reception of directional signals by utilizing individual arrays and / or by combining elements within an array so that signals at a particular angle cause constructive or destructive interference. Beamforming for transmission is achieved by controlling the phase and relative amplitude of the transmitted signal at each radiating element in the array to create a desired pattern of constructive and destructive interference at a desired wavefront. In contrast, beamforming for reception is achieved by combining information from various elements of the array so that radiation in a target spatial region is preferentially observed.

[0057] In the illustrated example, the network device 210 (e.g., gNodeB or a part thereof) and the 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 a specific spatial direction and / or within a specific spatial angular sector or width.

[0058] Continuing to refer to Figure 1, various examples of beam 220 of the network device 210 and various examples of beam 260 of the UE 150 are shown. When using highly directional beams, significant differences in directionality may prevent some of the network device beams 120 from being used with some of the UE beams 160. Therefore, in the embodiment, the UE 150 “sweeps” its beam 260 and the network device 210 “sweeps” its beam 220 to determine which beam pairing has the highest signal power and is therefore most usable for communication. Due to various propagation conditions, beams that are not perfectly aligned in direction may also have the highest signal power. Sweeping will be discussed in more detail in relation to Figure 3. After identifying such beam pairings, the UE 150 and the network device 210 may use the identified beams to initiate an access procedure for the UE 150 to access the network device 210.

[0059] Figure 3 shows an exemplary embodiment of a UE sweeping the received beam of an SSB burst. Using the beam example shown in Figure 2, the network device 210 sequentially forms beams B1, B2, B3, and B4. Each beam formation is called a “burst.” The network device 210 may generate bursts at intervals so that the UE 150 can observe them. Each time interval is called a “burst period” and may be longer than the duration of the burst.

[0060] In the 5G NR example, each beam within a burst transmits information about the beam in a form called a signal synchronization block (SSB). Network equipment 210, which may be a gNodeB or part of it, transmits the SSB in each beam within the burst. In some examples, network equipment 210 may operate using one SSB (single-beam operation) or multiple SSBs (multi-beam operation). In embodiments, UE 150 may receive an SSB burst for each of its receiving beams. In the example of the four receiving beams R1, R2, R3, and R4 shown in Figure 2, four intervals are required to receive bursts for all four receiving beams, as shown in Figure 3. In some examples, UE 150 may operate using a single beam (e.g., an omnidirectional beam). The SSB of an SSB burst can be provided by one or more (same-location or different-location) TRPs (Transmission Receiving Points). The duration between bursts is called the "burst period". In a 5G NR network, SSB bursts can each last for 5 milliseconds, and the burst cycle can have a default duration of 20 milliseconds.

[0061] In the 5G NR example, each SSB contains system information (SI) in the form of a master information block (MIB) and several system information blocks (SIBs). The SI is divided into a minimum SI and other SIs. The minimum SI contains basic information available for accessing network nodes and information for obtaining any other SIs. The minimum SI includes an MIB that contains cell prohibited status information and physical layer information for the cell to receive further system information (e.g., CORESET#0 configuration). The MIB is broadcast periodically on the broadcast channel (BCH). The minimum SI also includes system information block 1 (SIB1), which defines the scheduling of other system information blocks and contains information for accessing network nodes. SIB1 is sometimes called the remaining minimum SI (RMSI) and is broadcast periodically on the downlink shared channel (DL-SCH).

[0062] Referring also to Figure 2, in the example of fifth-generation new radio (5G NR) as defined by the Third Generation Partnership Project (3GPP), a unified transmission configuration indicator (TCI) framework is used for beam configuration and / or indication. For example, network equipment 210 may configure a set of TCI states on UE 150. Each TCI state may indicate at least a specific beam direction, or a group of beam directions that may correspond to a specific reference signal. In one example, the TCI state may be the DL TCI state for downlink (DL) communication from network equipment 210 to UE 150. In another example, the TCI state may be the UL TCI state for uplink (UL) communication from UE 150 to network equipment 210. In yet another example, the TCI state may be the joint TCI state for UL and DL communication between network equipment 210 and UE 150. Network equipment 210 may "activate" the UE by at least a subset of the configured TCI states. As used herein, “activating” a TCI state means that UE 150 can monitor a signal transmitted by network device 210 corresponding to the TCI state, such as a reference signal. In the example, activating a TCI state may mean that 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 the example, 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 a set and exclude one or more other configured TCI states in the set. Furthermore, network device 210 may select one of the activated TCI states to communicate with UE 150 and “indicate” the selected TCI state to UE 150.As used herein, “indicating” a TCI state means that UE 150 may be configured to use a beam (identified by a downlink reference signal) corresponding to an indicated TCI state in order to communicate with the network device 210. In various examples, UE 150 is ready to receive an indication of at least one of the activated TCI states and is ready to communicate with the network device 210 using the indicated TCI state within a specified time limit.

[0063] The examples in Figures 2 and 3 are for illustrative purposes only. In the embodiment, the number and direction of network node beams, as well as the number and direction of UE beams, may vary and may differ from those shown in Figures 2 and 3.

[0064] As explained above, since UEs may move from one area to another, cell switching or mobility procedures (e.g., Layer 3 handover or LTM) can be important to support continuous communication between the UE and the network. Furthermore, more efficient cell switching processes such as LTM can help avoid, or at least mitigate, disruptions to UE services when a UE moves from one cell coverage to another.

[0065] Figure 4 shows an exemplary embodiment of an LTM scenario. As shown in Figure 4, UE410 can communicate with and be serviced by network device 420 (e.g., gNB or part thereof), as indicated by the solid arrows. UE410 may be substantially similar to UE150 in Figure 1. Network device 420 may be substantially similar to network device 110 in Figure 1. Network device 420 that is actively or currently serviced to UE410 may be referred to as a serving cell. As UE410 moves toward the edge of a cell or area 402 that is serviced (or within its coverage) by network device 420, a cell switching procedure may be performed to hand over UE410 to an adjacent cell that is serviced by another network device 430, 440, for example. In the example shown in Figure 4, one adjacent cell is serviced by network device 430 and another adjacent cell is serviced by network device 440. Network device 440 may cover (or service) cell or area 406, and 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, adjacent cells may be called candidate cells. In the context of LTM, adjacent cells may be called LTM candidate cells.

[0066] The term Layer 1 / Layer 2 Triggered Mobility (LTM) is also sometimes referred to as L1 / L2 Triggered Mobility, L1 / 2 Inter-Cell Mobility, L1 / 2 Handover, or Lower Layer (L1 / 2) Mobility. These terms may be used interchangeably. An L1 / L2 signal, message, or command sent by a network node to trigger a cell switch in a UE is called a “cell switch command.” In LTM, decisions regarding cell switches are made at the MAC layer of the distributed unit (DU) based on L1 measurements. A cell switch command includes a MAC control element (MAC CE). The cell targeted by a cell switch command is sometimes referred to as the target cell in this specification. The mechanism of LTM is described in more detail below with reference to Figures 7–11.

[0067] According to one aspect of this disclosure, a network device 420 (serving cell) may activate a UE 410 based on the TCI state of a candidate cell and optionally indicate activated TCI states that may be used by the UE 410 in the case of a cell switch. In this regard, the network device 420 may transmit indications of one or more candidate cells (e.g., network devices 430 and 440) and activations of each of the lists of one or more TCI states for each of the one or more candidate cells. If the serving cell network device 420 detects a degradation in the operation or communication of the UE 410, it may transmit a cell switch command to the UE 410 via lower-layer signaling (e.g., L1 / L2 signaling). The cell switch command may indicate one of the one or more candidate cells as the target cell for the cell switch. In response to receiving the cell switch command, the UE 410 may switch to communication with the target cell by applying at least one of the respective one or more activated TCI states.

[0068] The example in Figure 4 is for illustrative purposes only. In the embodiment, the number of candidate cells and the number of activated TCI states (or beams) may vary and may differ from those shown in Figure 4.

[0069] The procedure by which a UE establishes communication with a target cell is called a random access procedure. Random access procedures may be used for initial access, small data transmission during inactivity, transition from RRC_Inactive to RRC_Connected, as well as beam fault recovery, connection re-establishment, handover, and cell addition, among other procedures that a person skilled in the art may recognize.

[0070] There are two types of random access procedures: competition-based random access (CBRA) and competition-free random access (CFRA). Figure 5 shows an example of a competition-based random access (CBRA) procedure. In the illustrated example, the signal includes a random access preamble (MSG1) transmitted by UE550 to network node 510 (e.g., gNodeB, or a part thereof), a random access response (MSG2) transmitted from network node 510 to UE550, a scheduled transmission (MSG3) transmitted from UE550 to network node 510, and a competition resolution (MSG4) transmitted from network node 510 to UE550.

[0071] In the case of MSG1, UE550 selects an available random access preamble based on informational elements within the SSB, such as the signal synchronization block (SSB) described above in relation to Figure 3. UE550 transmits the random access preamble (MSG1) to network node 510 using specific time and frequency resources known as random access occasions (ROs). UE550 also provides the network with an ID called a Random Access Radio Network Temporary ID (RA-RNTI) so that the network can deal with it in the next step.

[0072] In the case of MSG2, network node 110 detects the preamble, calculates various quantities, and sends a physical uplink shared channel (PUSCH) uplink (UL) grant to UE550. This is called a Random Access Response (RAR) and is sent as MSG2 to UE550 along with the associated RA-RNTI, indicating to UE550 the frequency and time at which MSG3 can be transmitted on PUSCH.

[0073] In the case of MSG3, in response to receiving MSG2 from network node 510, UE550 sends MSG3 using the UL grant provided in RAR. Since RAR provides time resource allocation, UE550 sends MSG3 to network node 510 at the timing specified by the time resource allocation, resulting in a scheduled transmission. This MSG3 is sometimes called a Radio Resource Control (RRC) connection request message.

[0074] In the case of MSG4, network node 510 may send MSG4 to UE550 for conflict resolution. Conflict resolution may operate in the manner specified by 3GPP for 5G NR. Assuming that the conflict resolution is successfully resolved after the random access procedure, UE550 connects to network node 510. After the connection is established, various procedures are handled by the gNB-CU according to the CU-DU partitioning. Other aspects of conflict-based random access (CBRA) will be understood by those skilled in the art.

[0075] Another type of random access procedure is conflict-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 to network node 510 as MSG1 in a random access request. MSG2 and MSG3 are then similar to those described in relation to CBRA. In CFRA based on the use of an assigned random access preamble, conflict resolution is not required. Other embodiments of conflict-free random access (CFRA) will be understood by those skilled in the art.

[0076] LTM and random access procedures will be described in reference to Figures 6A and 6B. While Figures 6A and 6B show examples of cell-switching procedures, other types of cell-switching procedures (e.g., Layer 3 handovers) are intended and understood to be included within the scope of this disclosure. Referring here to Figures 6A and 6B, examples of the signals and operations of LTM and random access procedures in relation to cell-switching procedures between DUs are shown. The inter-DU scenarios are illustrative, and aspects of this disclosure may also apply to scenarios within a DU. If the source DU and target DU are supported by different CUs, the source DU may be supported by the source CU, and the target DU may be supported by the target CU, and these can communicate via the Xn interface. As previously stated, “transmit to,” “receive from,” and “cooperate with” (and their variations) include communications that may or may not include communications through one or more intermediate devices or nodes. All descriptions referring to a DU are also intended to be treated as referring to a network node that supports at least one of the DU functions or Layer 2 protocols of a radio access network (RAN). Any mention of a CU is also intended to be treated as referring to a network node that supports 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 actions. It will be understood that the signals described may have associated actions, and the actions described may have associated signals. Therefore, the signals described may be actions, and the actions described may be signals.

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

[0079] In signal 601, the UE transmits the 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 the reference signal of the serving cell. The L3 measurement report may indicate, for example, that the UE is approaching the end of the cell and therefore needs to initiate the handover procedure. In signal 602, the source DU transmits the L3 measurement report to the CU, and the CU receives the L3 measurement report from the source DU. In operation 603, the CU performs a handover (HO) decision based on the L3 measurement report to determine whether it needs to prepare for a handover. In the illustrated embodiment, the CU determines that it needs to prepare for a handover.

[0080] In signal 604, the CU transmits a UE context setting request to the target DU in order to prepare the target DU for handover by setting the UE context on the target DU. The target DU receives the UE context setting request from the CU and sets the UE context. In signal 605, the target DU provides an acknowledgment by transmitting a UE context setting response to the CU, and the CU receives the UE context setting response from the target DU. Although one target DU is shown, there may be multiple target DUs if there are multiple candidate cells. The signals in 604 and 605 may be used for each of the target DU and any multiple candidate cells. In the following description, candidate cells are mentioned to indicate that there may be one or more candidate cells, and, where necessary, the target DUs supporting the candidate cells are also mentioned. If the target DU and source DU are supported by different CUs, the CUs may communicate using the Xn interface. For convenience, only one CU (the CU supporting the source DU) is shown, but the disclosed technique is intended to apply to situations with multiple CUs as well.

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

[0082] In signals 604-607, the CU, target DU, and source DU may coordinate with each other regarding the timing advance acquisition and configuration of candidate cells. Timing advance refers to information used by the UE to time uplink transmissions to network nodes so that they arrive at the network nodes in accordance with the receive time window. This information may be referred to herein as the 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, timing advance acquisition, or TA acquisition (or variations thereof). As described herein above, the term “acquire” (and variations thereof) includes acquisition in the first instance or reacquisition after the first instance. In embodiments, the source DU and target DU may coordinate (via the CU) how the UE acquires the TA. In embodiments, the UE may acquire separate TA values ​​for each candidate cell.

[0083] In embodiments, a TA may be acquired based on a random access (RA) procedure (either CFRA or CBRA), which includes, but is not limited to, RA procedures ordered by a physical downlink control channel (PDCCH), RA procedures triggered by an UE, and / or RA procedures triggered by higher layers from a network node (other than L3 handover commands). In embodiments, a TA may be acquired based on, but is not limited to, non-RA procedure methods, including, among others, sounding reference signal (SRS) based TA acquisition, received timing difference based mechanisms (such as those in LTE), and / or UE-based TA measurement. RA-based and non-RA-based methods for such TA acquisition are within the scope of this disclosure.

[0084] In operation 608, the CU creates an RRC reconfiguration message that includes the measurement configuration for the L1 cell change, the configuration for the prepared cell, and the TA acquisition configuration and trigger for the candidate cell. In embodiments, if CU involvement is required later (in the execution phase), the RRC reconfiguration message may include the TA configuration. The TA configuration may specify, for example, how the UE acquires the TA. In embodiments, the TA acquisition method can be configured / triggered (in conjunction with the source DU) based on the L3 measurement by the CU.

[0085] In signal 609, the CU transmits an RRC reconfiguration message to the source DU using downlink (DL) RRC message forwarding, and the source DU receives the RRC reconfiguration message from the CU. As previously mentioned, the RRC reconfiguration message may include the TA configuration and the activated or indicated TCI status information as described above. In signal 610, the source DU transmits the RRC reconfiguration message to the UE and forwards 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. In signal 611, the UE responds by transmitting an RRC reconfiguration complete message to the source DU using uplink (UL) RRC message forwarding, and the source DU receives the RRC reconfiguration complete message from the UE. In signal 612, the source DU transmits the RRC reconfiguration complete message to the CU and forwards it to the CU, and the CU receives the RRC reconfiguration complete message from the source DU. In the embodiment, signals 609-612 may be described as part of a logical connection between the UE and the CU, such as when the CU transmits an RRC message to the UE and the UE receives an RRC message from the CU.

[0086] In some embodiments, the signals and operations 601-612 described above may 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 the configuration. Those skilled in the art will understand what an L1 measurement is. An L1 measurement can measure the signal power of a list of reference signals configured by the network. For example, an L1 measurement can measure the signal power of a reference signal corresponding to an activated TCI state SSB. In signal 613, the UE periodically transmits an L1 measurement report to the source DU, and the source DU receives periodic L1 measurement reports from the UE.

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

[0089] In operation 615, the UE performs TA acquisition of the candidate cell using the TA acquisition method specified in the RRC reconfiguration message of operation 608. As described above, the TA may be acquired based on a random access (RA) procedure (either CFRA or CBRA), which includes, but is not limited to, RA procedures ordered by a physical downlink control channel (PDCCH), RA procedures triggered by the UE, and / or RA procedures triggered by higher layers from the network node (other than L3 handover commands). In embodiments, the TA may be acquired based on non-RA procedure methods, including, but is not limited to, sounding reference signal (SRS) based TA acquisition, received timing difference based mechanisms (such as those in LTE), and / or UE-based TA measurement. RA-based and non-RA-based methods for such TA acquisition are within the scope of this disclosure. After operation 615, if the TA acquisition procedure is successful, the UE may have a TA value for the candidate cell before the cell switch is triggered. If the TA acquisition procedure is unsuccessful, the UE cannot have a TA value for the candidate cell.

[0090] In signal 616, the UE continues to report L1 measurements, periodically transmitting L1 measurement reports to the source DU, and the source DU receives periodic L1 measurement reports from the UE. In operation 617, the source DU decides whether the UE should change serving cells. In an embodiment, the source DU may decide that the UE should change serving cells if, for example, the L1 measurement falls below a threshold. When the source DU decides that the UE needs to be handed over to a cell (for example, a target cell supported by the target DU), the source DU triggers a cell switch using a cell switch command (for example, MAC CE).

[0091] In signal 618, a cell switch command (e.g., MAC CE) is transmitted by the source DU to the UE, and the UE receives the cell switch command (e.g., MAC CE) from the source DU. In an embodiment, the cell switch command may include the TA value of the target cell. In an embodiment, the cell switch command may include the TA configuration to be used by the UE during and / or after the cell switch. The source DU may have the TA configuration by receiving an RRC message in signal 609.

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

[0093] In signal 621, to initiate communication with the target DU, the UE transmits an RRC reconfiguration complete message to the target DU using an already configured uplink (UL) resource, and the target DU receives the RRC reconfiguration complete message from the UE. In signal 622, the target DU transmits the RRC reconfiguration complete message to the CU using UL RRC message forwarding, and the CU receives the RRC reconfiguration complete message from the target DU. In 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 the UE context release command / request from the CU. The source DU releases the UE context in response to the UE context release command / request. In signal 624, the source DU transmits a UE context release complete message to the CU, and the CU receives the UE context release complete message from the source DU. In operation 625, the CU performs a path switch to the target DU as a new DU supporting the serving cell.

[0094] The signals and operations in Figures 6A and 6B are for illustrative purposes only, and variations are considered to be within the scope of this disclosure. For example, the signals and operations may assume one TA value per physical cell ID (PCI). In embodiments, to cover multi-TRP (multiple transmission receiving point) scenarios, the UE may be configured and required to acquire multiple TAs for PCI, such as different TA values ​​for different sets of TCI states. In embodiments, the signals and operations may include others not shown in Figures 6A and 6B. In embodiments, the signals and operations may not include all of the signals and operations shown in Figures 6A and 6B. In embodiments, the signals and operations may be performed in an order different from the order shown in Figures 6A and 6B. Such embodiments, and other embodiments, are considered to be within the scope of this disclosure.

[0095] Regarding cell switching, various scenarios are possible. Figures 7 to 9 describe various cell switching scenarios below. In summary, Figure 7 concerns a cell switching scenario in which the activated or indicated TCI state received before or during the cell switching command is not maintained after the cell switching is successfully completed. Figure 8 concerns a cell switching scenario in which the TA value is not provided in the cell switching command. Figure 9 concerns a cell switching scenario in which the TA value and uplink transmission resources (or monitoring of UL resource scheduling) are configured in the UE before or during the cell switching command. In Figures 7 to 9, signals and operations are performed between the UE, serving cell, and target cell for the cell switching. One or more of the signals and operations may be performed in relation to the LTM operations in Figures 6A and 6B. The UE may be similar to UE150 in Figures 1 and 2. The serving cell and target cell may be similar to network devices 420 and / or 430.

[0096] In relation to Figures 7-9, the following paragraphs describe various signals and operations. It will be understood that the signals described may have associated operations, and the operations described may have associated signals. Thus, the signals described may be operations, and the operations described may be signals. Furthermore, while Figures 7-9 include several enumerated steps, the modes of operation may include additional steps before, after, and between the enumerated steps. In some modes, one or more of the enumerated steps may be omitted, and they may be performed in a different order. Such variations are considered to be within the scope of this disclosure.

[0097] Figure 7 illustrates an exemplary embodiment of cell switch operation, where activated or indicated TCI states received before or during a cell switch command are not maintained after the cell switch is successfully completed. Signals 710 and 715 correspond to one scenario, and signals 720 and 725 correspond to another scenario. Prior to signal 710 or 720, the UE has established a connection with the DU supporting the serving cell and a (logical) connection with the CU supporting the DU.

[0098] In the scenarios of signals 710 and 715, the activation of the target cell's TCI state and an indication of at least one TCI state of the target cell are provided to the UE prior to the cell switch command. In signal 710, the serving cell transmits a MAC CE containing the activation of the target cell's TCI state to the UE, and the UE receives the MAC CE. In 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 a cell switch command (not shown). The indicated TCI state (index) may be a joint TCI state, meaning it is used in both downlink and uplink communications. Alternatively, the indicated TCI state (index) may be a pair of TCI states (i.e., a pair of downlink TCI states and uplink TCI states), or an indicated TCI state (index) (e.g., a downlink TCI state or an uplink TCI state).

[0099] In the signal 720 and 725 scenarios, the activated TCI state of the target cell is provided to the UE prior to the cell switch command, and the indicated TCI state is provided to the cell switch command. In signal 720, the serving cell transmits a MAC CE to the UE that includes the activation of the target cell's TCI state, and the UE receives the MAC CE. In signal 725, the serving cell transmits a MAC CE to the UE that includes a cell switch command with an indication of the target cell's activated TCI state, and the UE receives the MAC CE.

[0100] In various examples (not shown), the UE may receive a TCI state (index) in a cell switch command that operates to both activate and indicate at least one TCI state. In various examples, the UE may not have received an activation command for a TCI state before the cell switch, and may receive an activation command in the cell switch command. In such examples, the at least one TCI state provided in the cell switch command is an activated and indicated TCI state.

[0101] Following both signals 715 and 725, the operation proceeds to operation 730. In operation 730, a random access procedure is triggered before the cell switch is successfully completed and before the UE transmits an uplink message (e.g., RRC reconfiguration complete signal 621 or other message completing the cell switch) to the target cell. In various examples, the random access procedure may be triggered by the number of UL message retransmissions N (e.g., when the maximum number of configurable retransmissions is reached), the expiration of at least one timer that monitors the provision of UL message transmission (e.g., when the maximum time the UE has attempted to transmit a UL message in a provided UL grant is reached), or the observation that the quality of at least one RS in the TCI state is below a threshold, or for any other reason, before at least one UL message is successfully delivered from the UE to the target cell.

[0102] If operation 730 continues, the UE and target cell perform and successfully complete a 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 to the target cell that completes the cell switch procedure, such as an RRC configuration complete message (621, Figure 6), or any message that completes the cell switch to the target cell. In various examples, the UL message may be a MAC CE. Once the random access procedure is successfully completed, the activated and indicated TCI states of the target cell are cleared, and the UE then proceeds with no activated or indicated TCI states for the new serving cell. Rather, in operation 735, the UE prepares uplink (UL) and downlink (DL) communications by measuring the DL reference signal (RS) selected for the random access procedure in operation 730. In operation 740, based on the DL RS measurement, the UE transmits an L1 measurement report (e.g., L1-RSRP) to the new serving cell, and the new serving cell receives the L1 measurement report.

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

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

[0105] In summary, the signals and actions in Figure 7 did not apply the activated or indicated TCI state of the target cell to the new serving cell after the random access procedure was completed in action 730. As a result, signals and actions 735-760 were required before the UE could 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 reduced or eliminated by the signals and actions shown in Figures 8 and 9, which are described below.

[0106] Figure 8 relates to a cell switch scenario in which the TA value is not provided in the cell switch command. In various examples, the UE may acquire / receive the TA value of the target cell before the cell switch command, but the cell switch command may not provide the UE's TA value. In this case, the UE may assume that the TA value of the target cell is not provided (even though it had previously acquired the TA value). Alternatively, in various examples, the UE may decide that the previously acquired TA value is still valid even if the TA value is not provided in the cell switch command. In various examples, the UE's decision may be a configurable configuration, i.e., the configuration may be configured to cause the UE to decide to use the previously acquired TA value if the TA value is not provided in the cell switch command but the UE acquired the TA value before the cell switch, or the configuration may be configured to cause the UE to assume that the TA value is not provided. Figure 8 includes the same signals 710 and 715 and the same signals 720 and 725 as in Figure 7. Following both signals 715 and 725, either option 1 (signals and actions 830-834) or option 2 (signals and actions 840-844) may be executed.

[0107] In both Option 1 and Option 2, the UE and the target cell perform a random access procedure and complete it successfully, the target cell becomes the new serving cell, and then maintain at least the activated TCI state of the target cell as the activated TCI state of the new serving cell. Option 1 further maintains the indicated TCI state of the target cell as the indicated TCI state of the new serving cell, but Option 2 does not. In Option 2, where the indicated TCI state is not maintained, the UE may assume that the reference signals for downlink and uplink communications are the selected DL RS of the random access procedure until the UE receives an indication for at least one of the activated TCI states.

[0108] For Option 1, in operation 830, the UE determines that no TA value is provided in the cell switch command (i.e., assumes that the target cell does not have a TA value in this scenario), and the UE stores / maintains a list of activated TCI states and indicated TCI states (if available / indicated). In various examples, if a TCI state (index) is provided in the cell switch command (e.g., in operation 725), the TCI state (index) may be stored in operation 830 as the activated TCI state and / or indicated TCI state. In operation 832, a random access procedure is triggered, the UE and the target cell execute the random access procedure, and the UE successfully completes the random access procedure. In various examples, a random access procedure may be triggered based on the determination that the cell switch command does not contain a TA value, even though a timing advance (TA) value was obtained before the cell switch command. The UE obtains the TA value of the target cell via the random access procedure. After the random access procedure is successfully completed (i.e., after the cell switch is complete), in operation 834, the UE maintains the activated TCI state of the target cell as the activated TCI state of the new serving cell, and maintains the indicated TCI state of the target cell as the indicated TCI state of the new serving cell. By maintaining the indicated TCI state, the UE and the new serving cell can perform data communication immediately after the random access procedure is completed, without the delay associated with the signals and operations 735-760 in Figure 7.

[0109] For Option 2, operation 840 is the same as operation 830, and operation 842 is the same as operation 832. After the random access procedure is successfully completed, in operation 844, the UE maintains the activated TCI state of the target cell as the activated TCI state of the new serving cell, but does not maintain the indicated TCI state of the target cell as the indicated TCI state of the new serving cell. By maintaining the activated TCI state, the UE and the new serving cell can avoid the signals and operations 735-750 in Figure 7. Therefore, in Option 2, signals and operations 755-765 are still required for the new serving cell to indicate the TCI state so that the UE and the new serving cell can perform data communication. However, compared to the operation in Figure 7, Option 2 further reduces the delay in preparing for data communication.

[0110] Figure 9 relates to a cell switch scenario in which the TA value and uplink transmission resources (or monitoring of UL resource scheduling) are configured at the UE before or during a cell switch command. In such a scenario, either Option 1 or Option 2 shown in Figure 9 may be used to reduce the delay in preparing data communication compared to Figure 7. In both Option 1 and Option 2, the UE and target cell perform and successfully complete a random access procedure, the target cell becomes the new serving cell, and then maintain at least the activated TCI state of the target cell as the activated TCI state of the new serving cell. Option 1 further maintains the indicated TCI state of the target cell as the indicated TCI state of the new serving cell, whereas Option 2 does not. In Option 2, where the indicated TCI state is not maintained, the UE may assume that the reference signal 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 of the activated TCI states.

[0111] For Option 1, in operation 910, the UE determines that a TA value has been provided to the target cell and that the UE is configured for UL transmission of the target cell (configured by UL resources or by monitoring downlink control information for the provision of UL resources). In operation 912, the UE attempts to transmit an uplink message to the target cell (e.g., the RRC reconfiguration complete message 621 in Figure 6B, or other messages completing the cell switch procedure) using the TA value and UL transmission resources. In the Option 1 scenario, the attempted transmission does not immediately succeed. In operation 914, before the attempted transmission is completed, the UE determines that a random access procedure to the target cell has been triggered, and the UE stores a list of activated TCI states and indicated TCI states (if available). In various examples, the random access procedure may be triggered by the number of UL message retransmissions N (e.g., when the maximum number of configurable retransmissions is reached), the expiration of at least one timer that monitors the provision of UL message transmission (e.g., when the maximum time a UE has attempted to transmit a UL message in a provided UL grant is reached), the observation that the quality of at least one RS in the TCI state is below a threshold, or any other reason.

[0112] In block 916, the UE and the target cell perform and successfully complete a random access procedure, and the target cell becomes the new serving cell. The random access procedure may be successfully completed by the UE transmitting at least one UL message to the target cell that completes the cell switch procedure, such as an RRC configuration complete message (621, Figure 6), or any message that completes the cell switch to the target cell. In various examples, the UL message may be a MAC CE. After the random access procedure is successfully completed, in operation 918, the UE maintains the activated TCI state of the target cell as the activated TCI state of the new serving cell and maintains the indicated TCI state of the target cell as the indicated TCI state of the new serving cell. By maintaining the indicated TCI state, the UE and the new serving cell can perform data communication immediately after the random access procedure is completed, without the delay associated with the signals and operations 735-760 in Figure 7.

[0113] For Option 2, signals and operations 920-926 are the same as those for 910-916. After the random access procedure is successfully completed, in operation 928, the UE maintains the activated TCI state of the target cell as the activated TCI state of the new serving cell, but does not maintain the indicated TCI state of the target cell as the indicated TCI state of the new serving cell. By maintaining the activated TCI state, the UE and the new serving cell can avoid signals and operations 735-750 in Figure 7. Therefore, in Option 2, signals and operations 755-765 are still required for the new serving cell to indicate the TCI state so that the UE and the new serving cell can perform data communication. However, compared to the operation in Figure 7, Option 2 further reduces the delay in preparing for data communication.

[0114] Therefore, compared to the signals and operations in Figure 7, the signals and operations in Figures 8 and 9 reduce or eliminate delays in data communication preparation after the UE and target cell have successfully completed the random access procedure, improving time and resource utilization by the UE and the network system.

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

[0116] As an example of a variation, in the case of downlink control reception in a target cell, if followUnifedTCI-State is not enabled, the UE may assume that the TCI state of the target cell (new serving cell) is not indicated for a CORESET at index 0 or / or a CORESET at index other than index 0 associated with a Common Search Space (CSS) set other than a Type 3-PDCCH (Physical Downlink Control Channel) CSS set. Those skilled in the art will understand CORESET, CSS, PDCCH, and their parameters and behavior.

[0117] As another example of variation, in the case of downlink control reception on a target cell, if the CORESET index value is associated with at least one type of physical downlink control channel (PDCCH) common search space (CSS) and the configuration includes at least one field corresponding to not applying an indication of one TCI state, the UE may determine that the TCI state of the target cell is not indicated. Based on this determination, the UE may apply a quasi-coexistence (QCL) source to monitor at least one CSS on at least one CORESET, based on the reference signal selected for the random access procedure.

[0118] In some variations, only the specified TCI state remains activated, while all other TCI states are deactivated.

[0119] In some variations, the cell switch command may include a configuration that maintains the TCI state. After the UE successfully completes a random access procedure by the target cell, the UE may decide, based on the indication of the cell switch command, to maintain the activated TCI state but not the indicated TCI state, or to maintain the indicated TCI state (which is also the activated state) but not the (other) activated TCI state, or to maintain both the indicated TCI state and the activated TCI state. In another example, the UE may be pre-configured to perform one of these actions (maintain / not maintain) when it receives the cell switch command and after the random access procedure has successfully completed, for example, if an RA procedure is triggered before the completion of the cell switch. Alternatively, whether the UE decides to maintain one or more of the TCI states (both the indicated TCI state and the activated TCI state, or only the activated TCI state, or only the indicated TCI state) may be configurable by the RRC (and configurable per target cell). If a TCI state is maintained as activated but not indicated, the target cell can, for example, based on a random access procedure, select an indicated TCI state after the cell switch is complete. In another example, if the UE maintains only an indicated TCI state (which is also one of the activated TCI states, but other previously activated TCI states are now deactivated / not activated), the network can communicate with the UE after the cell switch, but the burden on the UE can be reduced by not having to monitor all previously active TCI states (for example, the target cell can wait for the latest L1 report to decide which TCI state set to activate, and the UE can still be served using the indicated TCI state).In an example where the UE is configured to maintain both indicated and activated TCI states, this allows for communication using the indicated TCI state while the UE monitors other activated TCI states for low-latency beam switching in the target cell.

[0120] In some variations, when performing a random access procedure, the UE may select an SSB or QCL source SSB corresponding to an indicated TCI state if each signal-synchronous block (SSB) or quasi-coexistence (QCL) source SSB has a reference signal received power (RSRP) that exceeds a threshold.

[0121] In some variations, individual activations and TCI status indicators may be provided for each candidate cell.

[0122] As another example of variation, in various embodiments, it may be configurable whether the TCI state is stored / maintained, as described in relation to Figures 7-9. The configuration may be provided using RRC signaling. The configuration may be part of a candidate cell configuration (e.g., an LTM configuration). The configuration may be specific to a particular cell or specific to a set / group of candidate cells. The configuration may indicate whether the UE is configured to store / maintain the activated TCI state of a target cell. In various examples, the configuration may configure the UE to store the activation (and / or indication) of the TCI state of an intra-DU cell. In various examples, the configuration may configure the UE not to store the activation (and / or indication) of the TCI state of an inter-DU cell. The UE may simply apply the configuration because it may not know whether a cell is an intra-DU cell or an inter-DU cell. The configuration may indicate whether the UE is configured to store / maintain the activated TCI state of a target cell. The configuration may indicate whether the UE is configured to remember / maintain the indicated TCI state (i.e., the indicated TCI state is maintained and also activated). In various examples, a cell switch command may indicate whether the TCI state of the target cell is maintained actively. In various examples, a cell switch command may indicate whether the indicated TCI state of the target cell remains indicated. Such variations, and other variations, are considered to be within the scope of this disclosure.

[0123] Next, referring to Figure 10, a flowchart of an example of UE operation is shown. The operation in Figure 10 encompasses both Figures 8 and 9, and both options in Figure 8 and both options in Figure 9. In block 1010, the operation includes receiving one or more activated transmission configuration indicator (TCI) states of a candidate cell from the serving cell. In block 1020, the operation includes receiving a cell switch command from the serving cell to switch from the serving cell to a candidate cell, wherein the candidate cell is the target cell of the cell switch command. In block 1030, the operation includes performing a random access procedure by the target cell in response to the cell switch command, wherein after the random access procedure is successfully completed, the target cell becomes the new serving cell of the UE. In block 1040, the operation includes maintaining one or more activated TCI states as the activated TCI states of the new serving cell after the random access procedure by the target cell has been successfully completed.

[0124] The operation in Figure 10 is an example. In some embodiments, the operation may include additional steps before, after, and between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. Such variations are considered to be within the scope of this disclosure.

[0125] Next, referring to Figure 11, a flowchart of an example of target cell operation is shown. The operation in Figure 11 encompasses both Figures 8 and 9, and both options in Figure 8 and both options in Figure 9. In block 1110, the operation includes transmitting a number of transmission configuration indicator (TCI) states that can be activated for a candidate cell to the serving cell of the user equipment (UE), the transmission occurring before the cell switch command for the UE to switch from the serving cell to the candidate cell. In block 1120, the operation includes the UE performing a random access procedure after the cell switch command, the candidate cell becoming the UE's new serving cell upon successful completion of the random access procedure. In block 1130, the operation includes communicating with the UE after the UE's random access procedure has successfully completed, using the number of activated TCI states as the activated TCI states of the new serving cell, the communication occurring without transmitting the activated TCI states of the new serving cell to the UE.

[0126] The operation shown in Figure 11 is an example. In some embodiments, the operation may include additional steps before, after, and between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order. Such variations are considered to be within the scope of this disclosure.

[0127] Referring now to Figure 12, a block diagram of exemplary components of a UE or network device is shown. The device includes electronic storage 1210, a processor 1220, memory 1250, and a network interface 1240. Various components may be coupled together in a communicative manner. The processor 1220 may be any type of processor, including a single-core central processing unit (CPU), a multi-core CPU, a microprocessor, a digital signal processor (DSP), a system-on-a-chip (SoC), or any other type of processor. The memory 1250 is a volatile type of memory, such as RAM, or a non-volatile type of memory, such as NAND flash memory. The memory 1250 includes processor-readable instructions that can be executed by the processor 1220 to cause the device to perform various operations, including the operations mentioned herein, such as the operations in Figures 3 and 5-11.

[0128] The electronic storage 1210 may be any type of electronic storage used for data storage, including hard disk drives, solid-state drives, and / or optical discs, and may include them. The electronic storage 1210 stores processor-readable instructions for causing the device to perform operations, and also stores data associated with such operations, such as data related to the 5G NR standard, among other things. The network interface 240 may implement wireless network technologies such as 5G NR and / or other wireless network technologies.

[0129] The components shown in Figure 12 are merely examples, and those skilled in the art will understand that the apparatus may include other components not shown, and may include multiple of any of the components shown. Such embodiments, 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 that supports candidate cells, One or more processors, When executed by one or more processors, the network device will have at least: Transmitting one or more transmission configuration indicator (TCI) states that can be activated for a candidate cell to a serving cell of a user equipment (UE), wherein the transmission is performed before a cell switch command is issued by the UE to switch from a serving cell to a candidate cell. This involves executing a random access procedure by the UE after a cell switch command, and if the random access procedure completes successfully, the candidate cell becomes the new serving cell. After the random access procedure by the UE is successfully completed, the UE communicates with at least one of the one or more activated TCI states as one or more activated TCI states of the new serving cell, A network device comprising at least one memory that stores instructions for causing a new serving cell to communicate, such that communication is performed without the new serving cell transmitting one or more activated TCI states to the UE.

[0132] (Examples 1-2) A network device as described in Example 1-1, wherein when an instruction is executed by one or more processors during a random access procedure performed by a UE, the network device causes the UE to transmit at least the timing advance (TA) value of a candidate cell.

[0133] (Examples 1-3) A network device according to Example 1-1 or 1-2, wherein when an instruction is executed by one or more processors, the network device causes at least one of the one or more activated TCI states to communicate further with the UE using the indicated TCI state of a new serving cell after the random access procedure by the UE has been successfully completed, A network device in which communication occurs without the new serving cell transmitting the TCI state, which is indicated by the new serving cell, to the UE.

[0134] (Examples 1-4) The network device described in Examples 1-3, wherein one or more activated TCI states of a new serving cell include only the indicated TCI states of the new serving cell. A network device in which, of one or more activated TCI states that can be activated, TCI states other than the indicated TCI state are deactivated.

[0135] (Examples 1-5) A processor implementation method in a network device that supports candidate cells, A step of transmitting one or more transmission configuration indicator (TCI) states that can be activated for a candidate cell to a serving cell of a user equipment (UE), wherein the transmission step is performed before a cell switch command for the UE to switch from a serving cell to a candidate cell; A step in which a random access procedure is performed by the UE after a cell switch command, wherein if the random access procedure is successfully completed, the candidate cell becomes the new serving cell. After the random access procedure by the UE is successfully completed, the step is to communicate with the UE using at least one of the one or more activated TCI states as one or more activated TCI states of a new serving cell, The communication is performed in steps, without transmitting the TCI state in which the new serving cell is activated to the UE. A processor implementation method comprising:

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

[0137] (Examples 1-7) A processor implementation according to Example 1-5 or 1-6, further comprising the step of communicating with the UE using one of one or more activated TCI states as the indicated TCI state of a new serving cell after the random access procedure by the UE has been successfully completed, A processor implementation method in which communication is performed without the new serving cell transmitting the TCI state indicated to the UE.

[0138] (Examples 1-8) A processor implementation method according to Examples 1-7, wherein one or more activated TCI states of a new serving cell include only the indicated TCI states of the new serving cell. A processor implementation in which, of 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) Means for receiving one or more activated transmission configuration indicator (TCI) states of candidate cells from a serving cell, A means for receiving a cell switch command from a serving cell to a candidate cell, wherein the candidate cell is the target cell of the cell switch command. A means for executing a random access procedure by a target cell in response to a cell switch command, wherein the target cell becomes a new serving cell after the random access procedure is successfully completed. After the random access procedure by the target cell is successfully completed, means 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. A user-controlled device equipped with the following features.

[0140] (Example 2-2) The user equipment device described in Example 2-1, A means for determining, in response to a cell switch command, that a timing advance (TA) value has not been provided to the target cell in the cell switch command, A means for receiving the TA value of a target cell via a random access procedure and User equipment and devices that further include these features.

[0141] (Examples 2-3) A user device according to Example 2-1 or 2-2, Means for receiving an indication of one of one or more activated TCI states before performing a random access procedure on the target cell, After the random access procedure by the target cell is successfully completed, means for maintaining the indication of one TCI state as the indicated TCI state of the new serving cell. User equipment and devices that further include these features.

[0142] (Examples 2-4) A user device according to Example 2-3, wherein one or more activated TCI states of a new serving cell include only the indicated TCI states of the new serving cell. A user device in which, of one or more activated TCI states, all TCI states other than the indicated TCI state are deactivated.

[0143] (Examples 2-5) A user device according to Example 2-1 or 2-2, Before executing a random access procedure by the target cell, the cell switch command includes means for receiving an indication of one of the one or more activated TCI states, After the random access procedure by the target cell is successfully completed, based on the cell switch command, Maintain at least one of one or more activated TCI states, but do not maintain an indication for one TCI state. Maintain the indication of one TCI state, but do not maintain one or more activated TCI states, or Maintain at least one of one or more activated TCI states and maintain an indication for one TCI state. A means to determine one of the following User equipment and devices that further include these features.

[0144] (Examples 2-6) A user device according to Example 2-1 or 2-2, Means for receiving an indication of one of one or more activated TCI states before performing a random access procedure on the target cell, A means for determining whether to retain one TCI state indication as the indicated TCI state of a new serving cell after the random access procedure by the target cell has successfully completed. User equipment and devices that further include these features.

[0145] (Examples 2-7) In the user equipment described in Example 2-6, the decision not to maintain an indication of one TCI state is: The CORESET index value must be associated with at least one physical downlink control channel (PDCCH) common search space (CSS), and, Based on the fact that a configuration with at least one field value corresponds to not applying an indicator for one TCI state, A user device that, when an instruction is executed by one or more processors, causes the user device to further apply a quasi-coexistence (QCL) source to monitor at least one CSS on at least one CORESET based on a decision and a reference signal selected for a random access procedure.

[0146] (Examples 2-8) User device according to Example 2-3, wherein the means for performing a random access procedure by a target cell comprises means for selecting one of the SSBs or QCL source SSBs corresponding to one indicated TCI state when each signal synchronization block (SSB) or quasi-coexistence (QCL) source SSB has a reference signal received power (RSRP) that exceeds a threshold.

[0147] (Examples 2-9) A user device according to any one of Examples 2-1 to 2-8, A timing advance (TA) value is obtained before the cell switch command, and a means is provided to determine if the cell switch command does not include the TA value. Based on the decision, a means for determining when a random access procedure is triggered and User equipment and devices that further include these features.

[0148] (Examples 2-10) The user equipment device described in Example 2-1, A means for determining, in response to a cell switch command, whether the timing advance (TA) value of the target cell has been obtained and whether an uplink resource has been configured for the target cell or whether the scheduling of the uplink resource will be monitored, Based on the decision, means for transmitting an uplink message to a target cell using uplink resources, A means for determining whether a random access procedure was triggered before an uplink message was successfully transmitted to a target cell, A random access procedure is performed by means of a random access procedure that is triggered. User equipment and devices that further include these features.

[0149] (Examples 2-11) The user device described in Example 2-10, in which an instruction is executed by one or more processors, provides at least the following to the user device: Means for receiving an indication of one of one or more activated TCI states before performing a random access procedure on the target cell, After the random access procedure by the target cell is successfully completed, means for maintaining the indication of one TCI state as the indicated TCI state of the new serving cell. A user device that further enables this process.

[0150] (Examples 2-12) The user equipment described in Example 2-10, Means for receiving an indication of one of one or more activated TCI states before performing a random access procedure on the target cell, A means for determining whether to retain one TCI state indication as the indicated TCI state of a new serving cell after the random access procedure by the target cell has successfully completed. User equipment and devices that further include these features.

[0151] (Examples 2-13) In the user equipment device described in Example 2-12, the decision not to maintain an indication of one TCI state is: The CORESET index value must be associated with at least one physical downlink control channel (PDCCH) common search space (CSS), and, Based on the fact that a configuration with at least one field value corresponds to not applying an indicator for one TCI state, User device further comprises means for applying a quasi-coexistence (QCL) source to monitor at least one CSS on at least one CORESET, based on a decision and a reference signal selected for a random access procedure.

[0152] (Examples 2-14) A user device according to any one of Examples 2-1 to 2-13, wherein when an instruction is executed by one or more processors, the user device provides at least: A means for receiving the activated transmission configuration indicator (TCI) state of one or more of each candidate cell from a serving cell, for each of a plurality of candidate cells, A user device that allows multiple candidate cells to perform a further action involving the presence of candidate cells.

[0153] (Examples 2-15) A user device according to any one of Examples 2-1 to 2-14, wherein the cell switch command is a Layer 1 / Layer 2 Triggered Mobility (LTM) cell switch command.

[0154] (Examples 2-16) The steps include receiving one or more activated transmission configuration indicator (TCI) states of candidate cells from the serving cell, A step of receiving a cell switch command from a serving cell to switch from the serving cell to a candidate cell, wherein the candidate cell is the target cell of the cell switch command. A step for executing a random access procedure by a target cell in response to a cell switch command, wherein after the random access procedure is successfully completed, the target cell becomes a new serving cell. A processor implementation method comprising the steps of: after a random access procedure by a target cell has been successfully completed, maintaining one or more activated TCI states as the activated TCI states of a new serving cell.

[0155] (Examples 2-17) The processor implementation method described in Example 2-16, In response to a cell switch command, the step of determining that no timing advance (TA) value has been provided to the target cell in the cell switch command, A step of receiving the TA value of the target cell via a random access procedure and A processor implementation method that further enhances this feature.

[0156] (Examples 2-18) A processor implementation method as described in Example 2-16 or 2-17, Before performing a random access procedure on the target cell, the procedure includes receiving an indication of one of the one or more activated TCI states, A processor implementation method further comprising the step of maintaining an indication of one TCI state as the indicated TCI state of a new serving cell after a random access procedure by a target cell has been successfully completed.

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

[0158] (Examples 2-20) A processor implementation method as described in Example 2-16 or 2-17, Before performing a random access procedure on the target cell, the procedure includes receiving an indication of one of the one or more activated TCI states, After the random access procedure by the target cell is successfully completed, based on the cell switch command, Maintain at least one of one or more activated TCI states, but do not maintain an indication for one TCI state. Maintain the indication of one TCI state, but do not maintain one or more activated TCI states, or Maintain at least one of one or more activated TCI states and maintain an indication for one TCI state. The step of deciding one of them A processor implementation method that further enhances this feature.

[0159] (Examples 2-21) A processor implementation method as described in Example 2-16 or 2-17, Before performing a random access procedure on the target cell, the procedure includes receiving an indication of one of the one or more activated TCI states, After the random access procedure by the target cell is successfully completed, the step of deciding not to retain one TCI state indication as the indicated TCI state of the new serving cell. A processor implementation method that further enhances this feature.

[0160] (Examples 2-22) The processor implementation method described in Example 2-21, wherein the decision not to maintain an indication of one TCI state, The CORESET index value must be associated with at least one physical downlink control channel (PDCCH) common search space (CSS), and, Based on the fact that a configuration with at least one field value corresponds to not applying an indicator for one TCI state, Processor implementation method further comprising the step of applying a quasi-coexistence (QCL) source to monitor at least one CSS on at least one CORESET based on a decision and a reference signal selected for a random access procedure.

[0161] (Examples 2-23) A processor implementation according to Example 2-18, wherein the step of performing a random access procedure by a target cell comprises the step of selecting one of the SSBs or QCL source SSBs corresponding to one indicated TCI state if each signal synchronization block (SSB) or quasi-coexistence (QCL) source SSB has a reference signal received power (RSRP) that exceeds a threshold.

[0162] (Examples 2-24) A processor implementation method according to any one of Examples 2-16 to 2-23, The steps include: obtaining the timing advance (TA) value before the cell switch command and determining that the cell switch command does not include the TA value; A processor implementation method further comprising the step of determining, based on a decision, that a random access procedure is triggered.

[0163] (Examples 2-25) The processor implementation method described in Example 2-16, The steps include determining, in response to a cell switch command, that the timing advance (TA) value of the target cell has been obtained and that an uplink resource has been configured for the target cell or that the scheduling of the uplink resource will be monitored, Based on the decision, the steps include: transmitting an uplink message to the target cell using uplink resources; A step of determining that a random access procedure was triggered before the uplink message was successfully transmitted to the target cell, A random access procedure is executed in response to the random access procedure being triggered, and A processor implementation method that further enhances this feature.

[0164] (Examples 2-26) The processor implementation method described in Example 2-25, Before performing a random access procedure on the target cell, the procedure includes receiving an indication of one of the one or more activated TCI states, A processor implementation method further comprising the step of maintaining an indication of one TCI state as the indicated TCI state of a new serving cell after a random access procedure by a target cell has been successfully completed.

[0165] (Examples 2-27) The processor implementation method described in Example 2-25, Before performing a random access procedure on the target cell, the procedure includes receiving an indication of one of the one or more activated TCI states, After the random access procedure by the target cell is successfully completed, the step of deciding not to retain one TCI state indication as the indicated TCI state of the new serving cell. A processor implementation method that further enhances this feature.

[0166] (Examples 2-28) The processor implementation method described in Example 2-27, wherein the decision not to maintain an indication of one TCI state, The CORESET index value must be associated with at least one physical downlink control channel (PDCCH) common search space (CSS), and, Based on the fact that a configuration with at least one field value corresponds to not applying an indicator for one TCI state, Processor implementation method further comprising the step of applying a quasi-coexistence (QCL) source to monitor at least one CSS on at least one CORESET based on a decision and a reference signal selected for a random access procedure.

[0167] (Examples 2-29) A processor implementation method according to any one of Examples 2-16 to 2-28, The step of receiving the activated transmission configuration indicator (TCI) status of one or more of the candidate cells from the serving cell for each of the multiple candidate cells, A processor implementation method further comprising steps, wherein multiple candidate cells comprise candidate cells.

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

[0169] The embodiments and aspects disclosed herein are examples of the disclosure and can be implemented in various forms. For example, while certain embodiments are described herein as separate embodiments, each embodiment herein can be combined with one or more of the other embodiments herein. The specific structural and functional details disclosed herein should not be construed as limiting, but rather as representative grounds for the claims and for teaching a person skilled in the art how to make various uses of the disclosure in substantially any suitable detailed structure. Similar reference numerals throughout the description of the drawings may refer to the same or identical elements.

[0170] The phrases “in an aspect,” “in aspects,” “in various aspects,” “in some aspects,” or “in other aspects” may each refer to one or more of the same or different aspects as provided in this disclosure. The phrase “a plurality of” may refer to two or more.

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

[0172] Any method, program, algorithm, or code described herein may be translated into or expressed in a programming language or computer program. The terms “programming language” and “computer program” as used herein include, but are not limited to, any language used to specify instructions to a computer, including, but not limited to, the following languages ​​and their derivatives: assembler, Basic, batch file, BCPL, C, C+, C++, Delphi, Fortran, Java, JavaScript, machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, Visual Basic, meta-languages ​​that themselves specify programs, and all computer languages ​​of the first, second, third, fourth, fifth, or later generations. Databases and other data schemas, as well as other meta-languages, are also included. No distinction is made between interpreted languages, compiled languages, or languages ​​that use both compiled and interpreted forms. No distinction is made between compiled and source versions of a program. Therefore, if a programming language exists in multiple states (source, compiled, object, or linked, etc.), a reference to the program refers to any of those states. A reference to the program may include the actual instructions and / or the intent of those instructions.

[0173] While aspects of this disclosure are shown in the drawings, this disclosure is intended to be as broad as the art allows, and the specification is to be interpreted similarly; therefore, this disclosure is not intended to be limited to the drawings. Accordingly, the above description should not be construed as restrictive, but merely as an example of a particular aspect. Those skilled in the art will be able to envision other modifications within the claims and intent appended herein.

Claims

1. User equipment, One or more processors, When executed by the one or more processors, the user device has at least: Receiving the status of one or more activated transmission configuration indicators (TCIs) of candidate cells from the serving cell, Receiving a cell switch command from the serving cell to the candidate cell, wherein the candidate cell is the target cell of the cell switch command, In response to the cell switch command, the target cell executes a random access procedure, and after the random access procedure is successfully completed, the target cell becomes a new serving cell. After the random access procedure by the target cell is successfully completed, at least one of the one or more activated TCI states is maintained as the one or more activated TCI states of the new serving cell. At least one memory that stores the instruction to perform the action and A user-controlled device equipped with the following features.

2. When the instruction is executed by the one or more processors, the user device will have at least the following: In response to the cell switch command, it is determined that no timing advance (TA) value has been provided to the target cell in the cell switch command. The random access procedure described above involves receiving the TA value of the target cell. The user device according to claim 1, which further enables the following.

3. When the instruction is executed by the one or more processors, the user device will have at least the following: Before executing the random access procedure by the target cell, an indication of one of the TCI states among the one-phase activated TCI states is received, After the random access procedure by the target cell is successfully completed, the indication of the one TCI state is maintained as the indicated TCI state of the new serving cell. The user device according to claim 2, which further enables the following.

4. The one or more activated TCI states of the new serving cell include only the indicated TCI states of the new serving cell. The user device according to claim 3, wherein, among the one or more activated TCI states, TCI states other than the indicated TCI state are deactivated.

5. When the instruction is executed by the one or more processors, the user device will have at least the following: Before executing the random access procedure by the target cell, the cell switch command receives an indication of one of the TCI states among the one-phase activated TCI states, After the random access procedure by the target cell is successfully completed, based on the cell switch command, Maintain at least one of the one or more activated TCI states, but do not maintain the indication of the one TCI state. The indication for the one TCI state is maintained, but the one or more activated TCI states are not maintained, or Maintain at least one of the one or more activated TCI states and maintain the indication of the one TCI state. To decide one of them The user device according to claim 2, which further enables the following.

6. When the instruction is executed by the one or more processors, the user device will have at least the following: Before executing the random access procedure by the target cell, an indication of one of the TCI states among the one-phase activated TCI states is received, After the random access procedure by the target cell is successfully completed, it is decided not to maintain the indication of one TCI state as the indicated TCI state of the new serving cell. The user device according to claim 2, which further enables the following.

7. The decision not to maintain the indication for one of the TCI states, The CORESET index value is associated with at least one physical downlink control channel (PDCCH) common search space (CSS), and A configuration having at least one field value corresponds to not applying the indication for the one TCI state. Based on, The user device according to claim 6, wherein when the instruction is executed by the one or more processors, the user device further causes the user device to apply at least a quasi-coexistence (QCL) source for monitoring at least one CSS on at least one CORESET based on the decision and a reference signal selected for the random access procedure.

8. The user device according to claim 3, wherein when the random access procedure is performed by the target cell, the instruction is executed by one or more processors, and the user device is instructed to select at least one of the SSBs or QCL source SSBs corresponding to one of the indicated TCI states if each signal synchronization block (SSB) or QCL source SSB has a reference signal reception power (RSRP) that exceeds a threshold.

9. When the instruction is executed by the one or more processors, the user device will have at least the following: The timing advance (TA) value is obtained before the aforementioned cell switch command, and it is determined that the cell switch command does not include the TA value. Based on the above decision, it is determined that a random access procedure is triggered. The user device according to claim 1, which further enables the following.

10. When the instruction is executed by the one or more processors, the user device will have at least the following: In response to the cell switch command, it is determined that the timing advance (TA) value of the target cell has been obtained, and that an uplink resource has been configured for the target cell, or that the scheduling of the uplink resource will be monitored. Based on the above decision, the uplink resource is used to transmit the uplink message to the target cell, Determining 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, and it is determined that The user device according to claim 1, which further enables the following.

11. When the instruction is executed by the one or more processors, the user device will have at least the following: Before executing the random access procedure by the target cell, an indication of one of the TCI states among the one-phase activated TCI states is received, After the random access procedure by the target cell is successfully completed, the indication of the one TCI state is maintained as the indicated TCI state of the new serving cell. The user device according to claim 10, which further enables the following.

12. When the instruction is executed by the one or more processors, the user device will have at least the following: Before executing the random access procedure by the target cell, an indication of one of the TCI states among the one-phase activated TCI states is received, After the random access procedure by the target cell is successfully completed, it is decided not to maintain the indication of one TCI state as the indicated TCI state of the new serving cell. The user device according to claim 10, which further enables the following.

13. The decision not to maintain the indication for one of the TCI states, The CORESET index value is associated with at least one physical downlink control channel (PDCCH) common search space (CSS), and A configuration having at least one field value corresponds to not applying the indication for the one TCI state. Based on, The user device according to claim 12, wherein when the instruction is executed by the one or more processors, the user device further causes the user device to apply at least a quasi-coexistence (QCL) source for monitoring at least one CSS on at least one CORESET based on the decision and a reference signal selected for the random access procedure.

14. When the instruction is executed by the one or more processors, the user device will have at least the following: The process involves receiving the activated transmission configuration indicator (TCI) status of one or more of the candidate cells from the serving cell for each of the multiple candidate cells, The user device according to claim 1, wherein the plurality of candidate cells further cause the device to receive, comprising the candidate cells.

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

16. The steps include receiving the status of one or more activated transmission configuration indicators (TCIs) of candidate cells from the serving cell, A step of receiving a cell switch command from the serving cell to switch from the serving cell to the candidate cell, wherein the candidate cell is the target cell of the cell switch command. A step of performing a random access procedure by the target cell in response to the cell switch command, wherein after the random access procedure is successfully completed, the target cell becomes a new serving cell. After the random access procedure by the target cell is successfully completed, the step of maintaining the one or more activated TCI states as the activated TCI states of the new serving cell. A processor implementation method comprising:

17. In response to the cell switch command, the step of determining that no timing advance (TA) value has been provided to the target cell in the cell switch command, The steps include receiving the TA value of the target cell via the random access procedure described above, and The processor implementation method according to claim 16, further comprising:

18. Before executing the random access procedure by the target cell, the step of receiving an indication of one of the one or more activated TCI states, After the random access procedure by the target cell is successfully completed, the step of maintaining the indication of one TCI state as the indicated TCI state of the new serving cell. The processor implementation method according to claim 17, further comprising:

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

20. Before executing the random access procedure by the target cell, the step of receiving an indication of one of the one or more activated TCI states, After the random access procedure by the target cell is successfully completed, based on the cell switch command, Maintain at least one of the one or more activated TCI states, but do not maintain the indication of the one TCI state. The indication for the one TCI state is maintained, but the one or more activated TCI states are not maintained, or Maintain at least one of the one or more activated TCI states and maintain the indication of the one TCI state. The step of deciding one of them The processor implementation method according to claim 17, further comprising:

21. Before executing the random access procedure by the target cell, the step of receiving an indication of one of the one or more activated TCI states, After the random access procedure by the target cell is successfully completed, the step of deciding not to maintain the indication of one TCI state as the indicated TCI state of the new serving cell. The processor implementation method according to claim 17, further comprising:

22. The decision not to maintain the indication for one of the TCI states, The CORESET index value is associated with at least one physical downlink control channel (PDCCH) common search space (CSS), and A configuration having at least one field value corresponds to not applying the indication for the one TCI state. Based on, The processor implementation method according to claim 21, further comprising the step of applying a quasi-coexistence (QCL) source for monitoring at least one CSS on at least one CORESET based on the reference signal selected for the random access procedure based on the determination.

23. The processor implementation method according to claim 18, wherein the step of performing the random access procedure by the target cell comprises the step of selecting at least one of the SSBs or QCL source SSBs corresponding to one of the indicated TCI states if each of the signal synchronization block (SSB) or quasi-coexistence (QCL) source SSBs has a reference signal reception power (RSRP) that exceeds a threshold.

24. The steps include: obtaining a timing advance (TA) value before the cell switch command and determining that the cell switch command does not include the TA value; Based on the above decision, the step of determining that a random access procedure is triggered and The processor implementation method according to claim 16, further comprising:

25. The steps include determining, in response to the cell switch command, that the timing advance (TA) value of the target cell has been obtained, and that an uplink resource has been configured for the target cell, or that the scheduling of the uplink resource will be monitored, Based on the above decision, the steps include transmitting an uplink message to the target cell using the uplink resource, A step of determining that the random access procedure was triggered before the uplink message was successfully transmitted to the target cell, The random access procedure is performed in response to the random access procedure being triggered, and The processor implementation method according to claim 16, further comprising:

26. Before executing the random access procedure by the target cell, the step of receiving an indication of one of the one or more activated TCI states, After the random access procedure by the target cell is successfully completed, the step of maintaining the indication of one TCI state as the indicated TCI state of the new serving cell. The processor implementation method according to claim 25, further comprising the above.

27. Before executing the random access procedure by the target cell, the step of receiving an indication of one of the one or more activated TCI states, After the random access procedure by the target cell is successfully completed, the step of deciding not to maintain the indication of one TCI state as the indicated TCI state of the new serving cell. The processor implementation method according to claim 25, further comprising the above.

28. The decision not to maintain the indication for one of the TCI states, The CORESET index value is associated with at least one physical downlink control channel (PDCCH) common search space (CSS), and A configuration having at least one field value corresponds to not applying the indication for the one TCI state. Based on, The processor implementation method according to claim 27, further comprising the step of applying a quasi-coexistence (QCL) source for monitoring at least one CSS on at least one CORESET based on the reference signal selected for the random access procedure based on the determination.

29. The step of receiving the activated transmission configuration indicator (TCI) status of one or more of the candidate cells from the serving cell for each of the multiple candidate cells, The processor implementation method according to claim 16, further comprising the step that the plurality of candidate cells comprise the candidate cells.

30. The processor implementation method according to claim 16, wherein the cell switch command is a layer 1 / layer 2 triggered mobility (LTM) cell switch command.

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