Apparatus and method of communication

Abstract

The embodiment of the invention relates to a communication device and method. In one aspect, upon receiving a MAC CE indicating a cell handover from a first cell to a second cell, a terminal device may determine whether the first cell is a candidate cell allowing LTM. If the first cell is not a candidate cell allowing LTM, the terminal device may determine whether a layer 2 reset procedure is to be performed or not by determining a first identification value as an identification value of a serving cell, and comparing the first identification value with a second identification value for a second cell. In this manner, if the serving cell or the source cell is not the LTM candidate cell, the terminal device may determine whether to perform the L2 reset during the LTM cell handover.

Description

Technical Field

[0001] Embodiments of this disclosure generally relate to the telecommunications field, and particularly to devices and methods for communications of mobility (LTM) triggered by Layer 1 (L1) / Layer 2 (L2). Background Technology

[0002] Currently, it has been proposed to trigger changes, additions, or releases of serving cells through lower-layer signaling such as L1 / L2 signaling; this is also known as LTM. Using LTM, latency, overhead, and downtime can be reduced. However, the implementation of LTM is still incomplete and requires further development. Summary of the Invention

[0003] In general, embodiments of this disclosure provide methods, apparatus, and computer storage media for communication with LTM.

[0004] In a first aspect, a terminal device is provided. The terminal device includes a processor. The processor is configured to cause the terminal device to: receive a Media Access Control (MAC) element (CE) from a network device, the MAC element (CE) indicating a cell handover from a first cell to a second cell; and, based on a determination that the first cell is not a candidate cell permitted for LTM, perform an operation including: determining whether an L2 reset procedure will be performed or not by determining a first identifier value as the identifier value of the serving cell and comparing the first identifier value with a second identifier value for the second cell; performing the L2 reset procedure; skipping the L2 reset procedure; or applying a configuration of the L2 reset procedure included in the LTM configuration.

[0005] In a second aspect, a terminal device is provided. The terminal device includes a processor. The processor is configured to cause the terminal device to: receive a MAC CE from a network device, the MAC CE indicating a cell handover to a target candidate cell that allows LTM; and to de-enable authorization for the initial uplink transmission toward the target candidate cell during the cell handover based on at least one of the following: a random access procedure will be performed for the cell handover; the synchronization signal block (SSB) selected for the initial uplink transmission is not configured for authorization; or the initial uplink transmission is performed based on dynamic authorization.

[0006] In a third aspect, a terminal device is provided. The terminal device includes a processor. The processor is configured to cause the terminal device to:, during cell handover, perform an initial uplink transmission toward a target candidate cell that allows LTM based on configured authorization; initiate a first timer for the configured authorization and a second timer for retransmission of the initial uplink transmission based on the configured authorization; and stop the first and second timers based on a determination that a response to the initial uplink transmission has been received from the network device providing the target candidate cell during the operation of the first and second timers.

[0007] In a fourth aspect, a method of communication is provided. The method includes: receiving a MAC CE from a network device at a terminal device, the MAC CE indicating a cell handover from a first cell to a second cell; and, based on a determination that the first cell is not a candidate cell for LTM, performing an operation including: determining whether an L2 reset procedure will be performed or not by determining a first identifier value as the identifier value of the serving cell and comparing the first identifier value with a second identifier value for the second cell; performing the L2 reset procedure; skipping the L2 reset procedure; or applying a configuration of the L2 reset procedure included in the LTM configuration.

[0008] In a fifth aspect, a method of communication is provided. The method includes: receiving at a terminal device a MAC CE from a network device, the MAC CE indicating a cell handover to a target candidate cell that allows LTM; and enabling authorization for the configuration of an initial uplink transmission toward the target candidate cell during the cell handover based on at least one of the following: a random access procedure will be performed for the cell handover; the SSB selected for the initial uplink transmission is not configured for authorization; or the initial uplink transmission is performed based on dynamic authorization.

[0009] In a sixth aspect, a method of communication is provided. The method includes: at a terminal device, during cell handover, performing an initial uplink transmission toward a target candidate cell that allows LTM based on configured authorization; initiating a first timer for the configured authorization and a second timer for retransmission of the initial uplink transmission based on the configured authorization; and stopping the first and second timers based on a determination that a response to the initial uplink transmission has been received from the network device providing the target candidate cell during the operation of the first and second timers.

[0010] In a seventh aspect, a computer-readable medium is provided having instructions stored thereon. When executed on at least one processor, the instructions cause the at least one processor to perform the method according to any one of the fourth to sixth aspects of this disclosure.

[0011] Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0012] The above and other objects, features and advantages of this disclosure will become more apparent from the more detailed description of some embodiments thereof in the accompanying drawings, in which:

[0013] Figure 1A Example communication networks in which some embodiments of this disclosure may be implemented are shown;

[0014] Figure 1B A schematic diagram is shown illustrating network protocol layer entities that can be established at a device for a user plane (UP) protocol stack according to some embodiments of the present disclosure;

[0015] Figure 1C A schematic diagram is shown illustrating network protocol layer entities that can be established at the device for the control plane (CP) protocol stack according to some embodiments of the present disclosure;

[0016] Figure 1D A schematic diagram of an LTM process in which some embodiments of the present disclosure may be implemented is shown;

[0017] Figure 2 A schematic diagram illustrating a communication process according to an embodiment of the present disclosure is shown;

[0018] Figure 3 A schematic diagram of another communication process according to an embodiment of the present disclosure is shown;

[0019] Figure 4 A schematic diagram illustrating yet another communication process according to an embodiment of the present disclosure is shown;

[0020] Figure 5 Example methods of communication implemented at a terminal device according to some embodiments of the present disclosure are shown;

[0021] Figure 6 Another example method of communication implemented at a terminal device according to some embodiments of the present disclosure is shown;

[0022] Figure 7 This illustrates yet another example method of communication implemented at a terminal device according to some embodiments of the present disclosure; and

[0023] Figure 8 This is a simplified block diagram of an apparatus suitable for implementing embodiments of the present disclosure.

[0024] In all the accompanying drawings, the same or similar reference numerals denote the same or similar elements. Detailed Implementation

[0025] The principles of this disclosure will now be described with reference to some embodiments. It should be understood that these embodiments are described for illustrative purposes only and to assist those skilled in the art in understanding and implementing this disclosure, and do not imply any limitation on the scope of this disclosure. The disclosure described herein can be implemented in various ways other than those described below.

[0026] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0027] As used herein, the term "terminal device" refers to any device with wireless or wired communication capabilities. Examples of terminal devices include, but are not limited to, user equipment (UE), personal computers, desktop computers, mobile phones, cellular phones, smartphones, personal digital assistants (PDAs), portable computers, tablet computers, wearable devices, Internet of Things (IoT) devices, ultra-reliable and low-latency communication (URLLC) devices, Internet of Everything (IoE) devices, machine-type communication (MTC) devices, vehicular devices for V2X communication (where X represents a pedestrian, vehicle, or infrastructure / network), devices for integrated access and backhaul (IAB), spacecraft or aircraft in non-terrestrial networks (NTN) (including satellites and high-altitude platforms (HAPs), covering unmanned aerial vehicle systems (UAS)), extended reality (XR) devices (including different types of reality such as augmented reality (AR), mixed reality (MR), and virtual reality (VR)), unmanned aerial vehicles (UAVs) commonly referred to as drones (a type of aircraft without any human pilot), devices on high-speed trains (HSTs), or image capture devices (such as digital cameras), sensors, gaming devices, music storage and playback devices, or internet devices capable of wireless or wired internet access and browsing, etc. "Terminal equipment" can also have "multicast / broadcast" features to support public safety and mission-critical applications, V2X applications, transparent IPv4 / IPv6 multicast delivery, IPTV, smart TV, wireless services, wireless software delivery, group communications, and IoT applications. It can also be combined with one or more Subscriber Identity Modules (SIMs), i.e., so-called multi-SIM. The term "terminal equipment" can be used interchangeably with UE, mobile station, subscriber station, mobile terminal, user terminal, or wireless device.

[0028] The term "network device" refers to a device that provides or hosts a cell or coverage area in which terminal devices can communicate. Examples of network devices include, but are not limited to, NodeB (or NB), evolved NodeB (eNodeB or eNB), next-generation NodeB (gNB), Transmitter Receiver Point (TRP), Remote Radio Unit (RRU), Radio Headend (RH), Remote Radio Headend (RRH), IAB node, low-power node (such as femtonode, piconode), reconfigurable smart surface (RIS), etc.

[0029] Terminal devices or network devices can have artificial intelligence (AI) or machine learning capabilities. It typically includes models that have been trained from large amounts of data collected for a specific function and can be used to predict some information.

[0030] Terminal or network devices can operate on several frequency ranges, such as FR1 (410 MHz to 7125 MHz), FR2 (24.25 GHz to 71 GHz), bands greater than 100 GHz, and terahertz (THz). They can also operate on licensed / unlicensed / shared spectrum. In multiple wireless dual connectivity (MR-DC) applications, terminal devices can have more than one connection to network devices. Terminal or network devices can operate in full-duplex, flexible-duplex, and cross-split-duplex modes.

[0031] The embodiments of this disclosure can be executed in test equipment, such as signal generators, signal analyzers, spectrum analyzers, network analyzers, test terminal equipment, test network equipment, and channel simulators.

[0032] In one embodiment, the terminal device can be connected to a first network device and a second network device. One of the first and second network devices can be a master node, and the other can be a slave node. The first and second network devices can use different Radio Access Technologies (RATs). In one embodiment, the first network device can be a first RAT device, and the second network device can be a second RAT device. In one embodiment, the first RAT device is an eNB, and the second RAT device is a gNB. Information related to different RATs can be transmitted to the terminal device from at least one of the first or second network devices. In one embodiment, first information can be transmitted from the first network device to the terminal device, and second information can be transmitted from the second network device directly or via the first network device to the terminal device. In one embodiment, information related to the configuration of the terminal device configured by the second network device can be transmitted from the second network device via the first network device. Information related to the reconfiguration of the terminal device configured by the second network device can be transmitted from the second network device directly or via the first network device to the terminal device.

[0033] As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term “comprising” and its variations should be understood as open-ended terms, meaning “including but not limited to.” The term “based on” should be understood as “at least partially based on.” The terms “one embodiment” and “embodiment” should be understood as “at least one embodiment.” The term “another embodiment” should be understood as “at least one other embodiment.” The terms “first,” “second,” etc., may refer to different or the same objects. Other explicit and implicit definitions may be included below.

[0034] In some examples, values, processes, or devices are referred to as “best,” “lowest,” “highest,” “smallest,” “maximum,” etc. It should be understood that such descriptions are intended to indicate that a choice can be made among many functional alternatives used, and that such a choice is not necessarily better, smaller, higher, or otherwise superior to other choices.

[0035] In the context of this disclosure, the term "cell handover" may be used interchangeably with "reconfiguration of a secondary cell group (SCG) or primary cell group (MCG) requiring synchronization" or "cell change". The term "PSCell" refers to the SpCell of an SCG, the term "PCell" refers to the SpCell of an MCG, and the term "SpCell" refers to the primary cell of an SCG or MCG. The term "SCell" refers to a secondary cell. The term "lower-layer signaling" may be used interchangeably with "L1 / L2 signaling". The term "Radio Resource Control (RRC) reconfiguration" may be used interchangeably with "RRC reconfiguration message". The term "candidate cell" may be used interchangeably with "LTM candidate cell" or "candidate cell allowing LTM". The term "target cell" may be used interchangeably with "target candidate cell", "candidate target cell", or "LTM target candidate cell".

[0036] When a terminal device moves from the coverage area of ​​one cell to another, a serving cell change may need to be performed at some point. Traditionally, serving cell changes are triggered by Layer 3 (L3) measurements and completed via a synchronized reconfiguration triggered by RRC signaling for changes to PCell and PSCell. All of these cases involve a full L2 (and L1) reset, resulting in longer latency, greater overhead, and longer downtime than beam-switching mobility. LTM aims to achieve serving cell changes via L1 / L2 signaling to reduce latency, overhead, and downtime.

[0037] LTM is the process by which a network device (e.g., a gNB) receives multiple L1 measurement reports from an end device (e.g., a UE), and based on these reports, the network device changes the serving cell of the end device via a cell handover command sent via a MAC CE signal. The cell handover command instructs the network device on the LTM candidate cell configuration previously prepared and provided to the end device via RRC signaling. The end device then switches to the target cell according to the cell handover command.

[0038] In the cell handover command, the network device instructs the terminal device whether to access the target cell using the random access (RA) procedure if the timing advance (TA) value is not provided, or to access the target cell using the physical uplink shared channel (PUSCH) transmission with the indicated TA value. For LTM without a random access channel (RACH), the terminal device can access the target cell via the license (CG) configured in the RRC signaling and select the CG timing associated with the beam indicated in the cell handover command. If the terminal device does not receive the CG in the RRC signaling, the terminal device can monitor the dynamically scheduled physical downlink control channel (PDCCH) from the target cell during LTM cell handover.

[0039] Embodiments of this disclosure provide a solution for communication for LTM. In one aspect, upon receiving a MAC CE indicating a cell handover from a first cell to a second cell, the terminal device determines whether the first cell is a candidate cell for LTM. If the first cell is not a candidate cell for LTM, the terminal device performs one of the following operations: determining whether an L2 reset procedure will be performed or not by determining a first identifier value as the identifier value of the serving cell and comparing the first identifier value with a second identifier value for the second cell; performing the L2 reset procedure; skipping the L2 reset procedure; or applying the configuration of the L2 reset procedure included in the LTM configuration. In this way, if the serving cell or the source cell is not an LTM candidate cell, the terminal device can determine whether to perform an L2 reset during an LTM cell handover.

[0040] On the other hand, upon receiving a MAC CE indicating a cell handover to a target candidate cell that allows LTM, the terminal device enables or disables the CG for the initial uplink transmission toward the target candidate cell during the handover based on at least one of the following: a random access procedure is performed for the cell handover; the SSB selected for the initial uplink transmission is not configured for CG; or the initial uplink transmission is performed based on dynamic licensing. In this way, CG resources for the initial uplink transmission for LTM can be appropriately handled.

[0041] On another front, when performing an initial uplink transmission toward a target candidate cell that allows LTM during cell handover based on the CG, the terminal device starts a first timer for the CG and a second timer for retransmission of the initial uplink transmission based on the CG. If a response to the initial uplink transmission is received from the network device providing the target candidate cell during the operation of the first and second timers, the terminal device stops the first and second timers. In this way, the RRC connection can be restored as quickly as possible.

[0042] The principles and implementation of this disclosure will be described in detail below with reference to the accompanying drawings. Examples of communication networks

[0043] Figure 1A A schematic diagram of an example communication network 100A in which some embodiments of the present disclosure may be implemented is shown. (See diagram for reference.) Figure 1A As shown, the communication network 100A may include terminal device 110 and network device 120. Network device 120 provides multiple cells (such as cells 121 and 122 shown) to serve the terminal device.

[0044] It should be understood that Figure 1AThe number of devices or cells is given for illustrative purposes and does not imply any limitation on this disclosure. The communication network 100A may include any suitable number of network devices and / or terminal devices and / or cells suitable for implementing this disclosure.

[0045] like Figure 1A As shown, terminal device 110 can communicate with network device 120 via a channel such as a wireless communication channel. Communication in communication network 100A can conform to any suitable standard, including but not limited to Global System for Mobile Communications (GSM), Long Term Evolution (LTE), LTE-Evolution, LTE-Advanced (LTE-A), New Radio (NR), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), Machine Type Communication (MTC), etc. Embodiments of this disclosure can be implemented according to any generational communication protocol currently known or to be developed in the future. Examples of communication protocols include, but are not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or sixth-generation (6G) networks.

[0046] Communication from terminal device 110 toward network device 120 is called uplink (UL) communication, while communication from network device 120 toward terminal device 110 in the opposite direction is called downlink (DL) communication. Terminal device 110 can move between the cells of network device 120 and possibly other network devices. In UL communication, terminal device 110 can transmit UL data and control information to network device 120 via the UL channel. In DL communication, network device 120 can transmit DL data and control information to terminal device 110 via the DL channel.

[0047] Communication in the communication network 100A can be performed according to the UP protocol stack and the CP protocol stack. Generally speaking, for communication devices (such as terminal devices or network devices), there are multiple entities in the protocol stack for multiple network protocol layers, which can be configured to perform corresponding processing on the data or signaling transmitted from and received by the communication device. Figure 1B A schematic diagram 100B illustrates network protocol layer entities that can be established at a device for the UP protocol stack according to some embodiments of the present disclosure. For example... Figure 1BAs shown, in the UP, each of the terminal device 110 and network device 120 may include entities targeting the L1 layer, i.e., entities targeting the physical (PHY) layer (also referred to as PHY entities), and one or more entities targeting higher layers (L2 and L3 layers, or higher), including entities targeting the media access control (MAC) layer (also referred to as MAC entities), entities targeting the radio link control (RLC) layer (also referred to as RLC entities), entities targeting the packet data convergence protocol (PDCP) layer (also referred to as PDCP entities), and entities targeting the serving data application protocol (SDAP) layer (also referred to as SDAP entities, which are established in 5G and higher generation networks). In some cases, the PHY, MAC, RLC, PDCP, and SDAP entities are in a stack structure.

[0048] Figure 1C A schematic diagram 100C illustrates a network protocol layer entity that can be established at a device for a CP protocol stack according to some embodiments of the present disclosure. For example... Figure 1C As shown, in the CP, each of terminal device 110 and network device 120 may include entities for the L1 layer, i.e., entities for the PHY layer (also referred to as PHY entities), and one or more entities for higher layers (L2 and L3 layers), including entities for the MAC layer (also referred to as MAC entities), entities for the RLC layer (also referred to as RLC entities), entities for the PDCP layer (also referred to as PDCP entities), and entities for the Radio Resource Control (RRC) layer (also referred to as RRC entities). The RRC layer can also be referred to as the Access Layer (AS) layer, therefore the RRC entity can also be referred to as the AS entity. Figure 1C As shown, terminal device 110 may also include entities for the Non-Access Stratum (NAS) layer (also referred to as NAS entities). The NAS layer on the network side is not located in the network device, but in the core network (CN, not shown). In some cases, these entities are in a stack structure.

[0049] In the context of this disclosure, L1 refers to the PHY layer, L2 refers to the MAC, RLC, PDCP, or SDAP layer, and L3 refers to the RRC layer. In the context of this disclosure, L1 or L2 can also be collectively referred to as lower layers, and L3 can also be referred to as higher layers. Therefore, L1 or L2 signaling can also be referred to as lower-layer signaling, and L3 signaling can also be referred to as higher-layer signaling.

[0050] Generally, communication channels are classified into logical channels, transport channels, and physical channels. Physical channels are the channels through which the PHY layer actually transmits information. For example, physical channels may include the Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel (PUSCH), Physical Random Access Channel (PRACH), Physical Downlink Shared Channel (PDSCH), and Physical Broadcast Channel (PBCH).

[0051] A transport channel is a channel between the PHY layer and the MAC layer. For example, a transport channel may include a broadcast channel (BCH), a downlink shared channel (DL-SCH), a paging channel (PCH), an uplink shared channel (UL-SCH), and a random access channel (RACH).

[0052] A logical channel is a channel between the MAC layer and the RLC layer. For example, a logical channel may include a dedicated control channel (DCCH), a common control channel (CCCH), a paging control channel (PCCH), a broadcast control channel (BCCH), and a dedicated traffic channel (DTCH).

[0053] Generally, the channel between the RRC layer and the PDCP layer is called a radio bearer (RB). Terminal device 110 can be configured with at least one data radio bearer (DRB) for carrying data plane data and at least one signaling radio bearer (SRB) for carrying control plane data. Four types of SRBs can be defined in the RRC layer: SRB0, SRB1, SRB2, and SRB3. SRB0 uses CCCH for RRC connection establishment or re-establishment. SRB1 uses DCCH and is established during RRC connection establishment. SRB2 uses DCCH and is established during RRC reconfiguration and after initial security activation. SRB3 uses DCCH and is established between terminal device 110 and the SN during dual-connection establishment.

[0054] return Figure 1A In some embodiments, terminal device 110 may be located within the coverage area of ​​cell 121 of network device 120, and terminal device 110 may communicate with network device 120 based on network configuration. In this case, cell 121 may be referred to as the serving cell of terminal device 110. Cell 122 may be referred to as the LTM candidate cell of terminal device 110.

[0055] In some embodiments, terminal device 110 can establish dual connectivity (i.e., simultaneous connectivity) with network device 120 and another network device (not shown). In some embodiments, network device 120 can act as a primary node (MN). In these embodiments, terminal device 110 can communicate with network device 120 via a set of serving cells. This set of serving cells forms an MCG, and the primary cell in the MCG is referred to as PCell. In some scenarios, PCell can change from cell 121 to cell 122. This is called handover (HO). In some embodiments, network device 120 can act as a secondary node (SN). In these embodiments, the set of serving cells provided by network device 120 forms an SCG, and the primary cell in the SCG is referred to as PSCell. In some scenarios, PSCell can change from cell 121 to cell 122. This is called PSCell change.

[0056] In some scenarios, network device 120 can receive L1 measurement reports from terminal device 110. Based on the L1 measurement reports, network device 120 can change the serving cell of terminal device 110 via MAC CE. This process is called LTM. Network device 120 can prepare one or more candidate cells and provide the candidate cell configurations to terminal device 110 via RRC messages. Then, LTM cell handover is triggered by network device 120 selecting one of the candidate cell configurations as the target configuration for LTM.

[0057] Cell handover triggering information can be transmitted in the MAC CE, which at least includes a candidate configuration index. Cell-specific radio bearer and measurement configurations can be part of the LTM candidate cell configuration. Terminal device 110 can perform contention-based random access (CBRA) or non-contention-based random access (CFRA) during cell handover. If terminal device 110 does not need to acquire a TA for the target cell during cell handover, it can also skip the random access procedure. RACH resources for CFRA can be provided in the RRC configuration.

[0058] Figure 1D A schematic diagram of a process 100D in which some embodiments of the present disclosure may be implemented is shown. For purposes of discussion, process 100D will be referred to... Figure 1A Described. Process 100D may involve, for example... Figure 1A The terminal device 110 and network device 120 are shown in the diagram. Network device 120 may be an MN or SN serving terminal device 110. In this example, network device 120 provides a serving cell for terminal device 110 and also provides one or more candidate cells for terminal device 110.

[0059] like Figure 1D As shown, during the LTM preparation phase, terminal device 110 can send a measurement report message (140) to network device 120. Network device 120 can decide (141) to use LTM and initiate LTM candidate preparation. Network device 120 can transmit an RRC reconfiguration message (142) to terminal device 110, which includes the configuration of one or more LTM candidate target cells (also referred to herein as LTM configuration or LTM candidate configuration). Terminal device 110 can store the configuration of LTM candidate target cells(s) and transmit an RRC reconfiguration completion message (143) to network device 120.

[0060] During the early synchronization phase, terminal device 110 may perform downlink (DL) synchronization with (multiple) candidate cells before receiving a cell handover command. Terminal device 110 may also perform early TA acquisition (i.e., uplink (UL) synchronization) with (multiple) candidate cells requested by network device 120 before receiving a cell handover command. This can be accomplished via CFRA triggered by a PDCCH command from the source cell, after which terminal device 110 sends a preamble to the indicated candidate cell. To minimize data interruption to the source cell due to CFRA towards (multiple) candidate cells, terminal device 110 does not receive random access responses (RARs) for TA value acquisition purposes, and the TA value of the candidate cell is indicated in the cell handover command. Terminal device 110 does not maintain a TA timer for candidate cells and relies on the network implementation to guarantee TA validity.

[0061] During the LTM execution phase, terminal device 110 can perform L1 measurements on the configured LTM candidate target cells(s) and transmit a lower-layer measurement report (146) to network device 120. L1 measurements can be performed as long as the RRC reconfiguration in step 142 is applied. Network device 120 can decide (147) to perform an LTM cell handover to the target cell and transmit a MAC CE (148) triggering the LTM cell handover, including the candidate configuration index of the target cell. Terminal device 110 can handover (149) to the target cell and apply the configuration indicated by the candidate configuration index. If terminal device 110 does not have a valid TA (Target Access Control) for the target cell, terminal device 110 can perform an RA (Range Access Control) procedure (150) toward the target cell.

[0062] During the LTM completion phase, terminal device 110 can complete the LTM cell handover process 151 by sending an RRC reconfiguration completion message to the target cell. If terminal device 110 has already performed the RA procedure in step 150, then when the RA procedure is successfully completed, terminal device 110 can consider the LTM execution to be successfully completed. For LTM without RACH, when terminal device 110 determines that network device 120 has successfully received the first UL data from terminal device 110, terminal device 110 can consider the LTM execution to be successfully completed.

[0063] Steps 144 to 151 can use the LTM candidate cell configuration provided in step 142, which is executed multiple times for subsequent LTM cell handover.

[0064] The embodiments disclosed herein provide a solution for communication for LTM. Details will be provided in reference to... Figures 2 to 4 Described. Example implementation of the L2 reset procedure for LTM

[0065] In some scenarios, for LTM, the identifier (ID) value can be configured in the LTM configuration for each LTM candidate cell. If the ID value of the serving cell is the same as the ID value of the target LTM candidate cell, the L2 reset procedure is not performed during LTM execution. If the ID value of the serving cell is different from the ID value of the target LTM candidate cell, the L2 reset procedure needs to be performed during LTM execution. The L2 reset procedure includes PDCP restoration for DRB and RLC re-establishment for RB.

[0066] In some cases, the serving cell can be an LTM candidate cell. In these cases, the ID value of the LTM candidate cell can serve as the ID value of the serving cell. However, in some cases, the serving cell may not be an LTM candidate cell, and it is unclear how to determine whether to perform the L2 reset procedure.

[0067] In view of the foregoing, embodiments of this disclosure provide a solution for the L2 reset process of LTM. This solution will be combined with the following Figure 2 Described.

[0068] Figure 2 A schematic diagram of a communication process 200 according to an embodiment of the present disclosure is shown. For purposes of discussion, process 200 will be referred to... Figure 1A Described. Process 200 may involve, for example... Figure 1AThe terminal device 110 and network device 120 are shown in the diagram. In this example, network device 120 provides a serving cell (e.g., cell 121) for terminal device 110, and also provides one or more candidate cells for terminal device 110. The serving cell can be an SpCell, PCCell, or PSCell of terminal device 110.

[0069] like Figure 2 As shown, network device 120 can transmit 205 configurations (also referred to herein as LTM configurations) of one or more candidate cells that enable LTM to terminal device 110. In some embodiments, network device 120 can transmit the configurations via RRC reconfiguration messages.

[0070] like Figure 2 As shown, network device 120 can transmit 210 MAC CE to terminal device 110, which indicates a cell handover from a first cell (also referred to as the source cell or serving cell) to a second cell (i.e., also referred to as the target candidate cell). That is, LTM cell handover is triggered.

[0071] Upon receiving a MAC CE, terminal device 110 can determine whether the first cell 220 is a candidate cell for allowing LTM. If the first cell is not a candidate cell for allowing LTM, terminal device 110 performs operations to determine whether to perform an L2 reset procedure.

[0072] refer to Figure 2 In some embodiments, if the first cell is not a candidate cell that allows LTM, the terminal device 110 can determine the first ID value 230 as the ID value of the serving cell.

[0073] In some embodiments, network device 120 may transmit a configuration of a first ID value 231 to terminal device 110. In other words, network device 120 configures an ID value for a serving cell that is not an LTM candidate cell for terminal device 110. This ID value is then used by terminal device 110 to determine whether an L2 reset procedure is performed during LTM execution from the serving cell to the target LTM candidate cell. In some embodiments, network device 120 may transmit the configuration of the first ID value in an RRC reconfiguration message instead of in the LTM candidate cell configuration associated with an LTM candidate cell.

[0074] Continue to refer to Figure 2 In some embodiments, terminal device 110 may set the first ID value 232 as a default value. In other words, if the serving cell or source cell is not an LTM candidate cell, terminal device 110 may set the ID value of the serving cell as a default value.

[0075] In some embodiments, upon receiving or determining a first ID value (i.e., upon receiving or determining the ID value of the serving cell), the terminal device 110 may set the maintained ID value for the serving cell in the UE variables to the received or determined value. Then, the terminal device 110 may determine whether to perform an L2 reset procedure by comparing the maintained ID value for the serving cell with the ID value of the target candidate cell.

[0076] Assume the second ID value is configured for the target candidate cell (i.e., the second cell). When determining the first ID value for the serving cell, the terminal device 110 can compare the first ID value with the second ID value to determine whether the L2 reset process will be executed or not. In some embodiments, if the first ID value and the second ID value are the same, the terminal device 110 can determine that the L2 reset process will not be executed. If the first ID value and the second ID value are different, the terminal device 110 can determine that the L2 reset process will be executed.

[0077] Continue to refer to Figure 2 In some embodiments, if the first cell is not a candidate cell that allows LTM, the terminal device 110 may perform the default behavior 240.

[0078] refer to Figure 2 In some embodiments, if the first cell is not an LTM-enabled candidate cell, the terminal device 110 may perform the L2 reset procedure 241. In other words, if the serving cell or the source cell is not an LTM candidate cell, the terminal device 110 may perform the L2 reset procedure during the LTM cell handover from the serving cell to the target candidate cell.

[0079] Continue to refer to Figure 2 In some embodiments, if the first cell is not a candidate cell that allows LTM, the terminal device 110 may skip the L2 reset procedure 242. In other words, if the serving cell or the source cell is not an LTM candidate cell, the terminal device 110 may not perform the L2 reset procedure during the LTM cell handover from the serving cell to the target candidate cell.

[0080] In some embodiments, when the serving cell or source cell is not an LTM candidate cell, network device 120 can configure in its LTM configuration L2 processing to be performed for LTM cell handover from the serving cell. (See reference...) Figure 2In some embodiments, if the first cell is not a candidate cell that allows LTM, the terminal device 110 may apply the L2 reset procedure configuration included in the LTM configuration (243). In other words, when performing an LTM cell handover, the terminal device 110 may determine whether the serving cell or the source cell is an LTM candidate cell. If the serving cell or the source cell is an LTM candidate cell, the terminal device 110 may ignore or may not apply the L2 processing configuration in the LTM configuration (e.g., information elements (IEs) "recoveryPDCP RRC" and "reestablishRLC").

[0081] Continue to refer to Figure 2 In some embodiments, if the first cell is not configured with a first ID value and / or the second cell is not configured with a second ID value, the terminal device 110 may determine that the 250 L2 reset procedure will not be executed. In some embodiments, if the first cell is not configured with a first ID value and / or the second cell is not configured with a second ID value, the terminal device 110 may determine that the 250' L2 reset procedure will be executed. In other words, if there is no ID value for at least one of the serving cell or the target candidate cell, the terminal device 110 executes the L2 reset procedure during the LTM cell handover execution from the serving cell to the LTM candidate cell, or the terminal device 110 does not execute the L2 reset procedure during the LTM cell handover execution.

[0082] So far, a solution for the L2 reset procedure for LTM has been described. In this way, if the serving cell or source cell is not an LTM candidate cell, the terminal device can determine whether to perform an L2 reset during LTM cell handover. Example implementation of CG processing for LTM

[0083] Embodiments of this disclosure also provide a solution for processing the initial UL transmission for LTM. This solution will be described below in conjunction with... Figure 3 Described.

[0084] Figure 3 A schematic diagram of another communication process 300 according to an embodiment of the present disclosure is shown. For purposes of discussion, process 300 will be referred to... Figure 1A Described. Process 300 may involve, for example: Figure 1A The terminal device 110 and network device 120 are shown in the diagram. In this example, network device 120 provides a serving cell (e.g., cell 121) for terminal device 110 and also provides a target candidate cell (e.g., cell 122) for terminal device 110. The serving cell can be an SPCell, PCell, or PSCell of terminal device 110.

[0085] like Figure 3 As shown, network device 120 can transmit 305 configuration (also referred to herein as LTM configuration) of one or more candidate cells that allow LTM to the terminal device 110. In some embodiments, network device 120 can transmit the configuration via an RRC reconfiguration message.

[0086] In some embodiments, the LTM configuration may include a CG for the initial UL transmission to the target candidate cell for LTM without RACH. For example, a Type 1 CG resource may be configured in the LTM configuration for the initial UL transmission to the target candidate cell.

[0087] like Figure 3 As shown, network device 120 can transmit a MAC CE 310 indicating a cell handover to the target candidate cell to terminal device 110. That is, LTM cell handover is triggered.

[0088] Based on the information in MAC CE, terminal device 110 can deactivate 320 CG. Some example embodiments will be described below in conjunction with embodiments 1 to 4. Example 1

[0089] In some scenarios, if the RA procedure is skipped for LTM cell handover, the terminal device can be pre-configured in the LTM configuration with Type 1 CG resources for the initial UL transmission toward the target candidate cell.

[0090] Traditionally, if the terminal device's RRC layer is configured with CG resources for the target candidate cell, the terminal device's MAC layer can initialize or reinitialize the CG resources. However, if the RA procedure is not skipped for LTM cell handover, the CG resources should be disabled. Otherwise, it may lead to resource waste.

[0091] In view of this, embodiments of the present disclosure provide a solution for disabling the CG. In this solution, if the RA procedure is to be performed for cell handover, the terminal device 110 can disable the CG.

[0092] In some embodiments, if the MAC layer of terminal device 110 determines that the RA procedure is not skipped for cell handover, terminal device 110 may de-enable the CG for the initial UL transmission. In some embodiments, terminal device 110 may clear the CG. In some embodiments, terminal device 110 may pause the CG. In some embodiments, terminal device 110 may treat the CG as invalid. In some embodiments, terminal device 110 may ignore the CG.

[0093] In some embodiments, if the RA process is skipped for cell handover, the terminal device 110 may apply a CG for the initial UL transmission toward the target candidate cell.

[0094] In some embodiments, if the RA procedure for cell handover is skipped, the terminal device 110 can configure the CG for the initial uplink transmission for the target candidate cell through the RRC layer of the terminal device 110. In other words, if the RRC layer of the terminal device 110 determines that the RA procedure for LTM cell handover is skipped, the RRC layer can configure the CG (or CG resources) for the initial UL transmission for the target candidate cell.

[0095] In some embodiments, if the RRC layer determines that the RA procedure is not skipped for LTM cell handover, the terminal device 110 may not configure a CG (or CG resource) for the initial UL transmission toward the target candidate cell.

[0096] In some embodiments, the RRC layer of terminal device 110 may make a determination based on an indication from a lower layer (e.g., the MAC layer). If the MAC layer of terminal device 110 receives an LTM cell handover command MAC CE from network device 120, and the MAC CE indicates that the RA process should be skipped (e.g., if the TA value to be used is included in the MAC CE, the MAC layer indicates to the RRC layer that the RA process should be skipped), then the MAC layer indicates to the higher layer (e.g., the RRC layer) that the RA process should be skipped.

[0097] In some embodiments, if the LTM cell handover execution is triggered for failure recovery from radio link failure, reconfiguration failure requiring synchronization, or cell handover failure (e.g., LTM execution is triggered while T311 is running), the terminal device 110 can determine that the RA procedure is not skipped for LTM cell handover.

[0098] In some embodiments, if the RA procedure is skipped for cell handover, the terminal device 110 may store the CG at its MAC layer and may initialize or reinitialize the CG at its MAC layer. In other words, the RRC layer of the terminal device 110 may configure CG resources for the target LTM candidate cell, and when the UL grant for the initial transmission for LTM cell handover is configured by a higher layer (e.g., the RRC layer), if the MAC layer of the terminal device 110 determines that the RA procedure is skipped for LTM cell handover, the MAC layer may store the UL grant provided by the higher layer as the configured UL grant and initialize or reinitialize the configured UL grant.

[0099] In some embodiments, if the MAC layer of terminal device 110 determines that the RA procedure is not skipped for LTM cell handover, terminal device 110 may not store the UL authorization provided by the higher layer and may not initialize or reinitialize the target candidate cell with CG resources for no RACH. In some embodiments, if the MAC layer of terminal device 110 receives an LTM cell handover command MAC CE from network device 120, and the MAC CE indicates that the RA procedure should be skipped (e.g., if the TA value to be used is included in the MAC CE, the MAC layer indicates to the RRC layer that the RA procedure is skipped), then the MAC layer of terminal device 110 may determine that the RA procedure should be skipped. In some embodiments, if the RRC layer determines that LTM cell handover execution is triggered for failure recovery from radio link failure, reconfiguration failure requiring synchronization, or cell handover failure (e.g., LTM execution triggered while T311 is running), then the RRC layer may indicate to the lower layer (e.g., the MAC layer) that the RA procedure is not skipped. The MAC layer may determine that the RA procedure is not skipped based on the indication from the higher layer (e.g., the RRC layer).

[0100] In this way, the RRC layer of terminal device 110 can configure the CG for the target candidate cell only when the RRC layer determines that the RA procedure for LTM cell handover is skipped. The MAC layer of terminal device 110 can store and initialize the CG only when the MAC layer determines that the RA procedure for LTM cell handover is skipped. Therefore, the CG resource is only available when LTM cell handover based on no RACH is to be performed, and not available in the case of LTM cell handover based on RA. Example 2

[0101] In some scenarios, the CG for the initial UL transmission for LTM can be associated with multiple SSBs. However, the SSB corresponding to the Transport Configuration Indication (TCI) state indicated in the LTM Cell Handover Command MAC CE may not be associated with a CG. The SSB corresponding to the TCI state indicated in the LTM Cell Handover Command MAC CE can also be referred to as the SSB selected for the initial UL transmission.

[0102] In view of this, embodiments of the present disclosure provide a solution for deactivating CG. In this solution, if the SSB selected for the initial UL transmission is not configured for CG, the terminal device 110 can deactivate CG.

[0103] In some embodiments, if the SSB selected for the initial UL transmission is not configured for the CG, the MAC layer of terminal device 110 may clear the CG. In some embodiments, if the SSB selected for the initial UL transmission is not configured for the CG, the MAC layer of terminal device 110 may pause the CG. In some embodiments, if the SSB selected for the initial UL transmission is not configured for the CG, the MAC layer of terminal device 110 may ignore the CG.

[0104] In some embodiments, if the SSB selected for the initial UL transmission is not configured for CG, the MAC layer of terminal device 110 may not store the UL grant provided by the higher layer, and may not initialize or reinitialize the target candidate cell with CG resources for no RACH. In some embodiments, if the SSB selected for the initial UL transmission is configured for CG, the terminal device may store the UL grant provided by the higher layer as the configured UL grant, and initialize or reinitialize the configured UL grant.

[0105] In some embodiments, the RRC layer of terminal device 110 may not configure a CG for the target candidate cell. In some embodiments, upon receiving an LTM cell handover command MAC CE, the MAC layer may consider the SSB associated with the TCI state indicated in the MAC CE as the SSB selected for the initial UL transmission toward the target candidate cell, and indicate the selected SSB to a higher layer (e.g., the RRC layer). Upon receiving the indication, if the SSB selected for the initial UL transmission is configured for the CG, the RRC layer of terminal device 110 may configure a CG for the target candidate cell.

[0106] In this way, if the SSB selected for the initial UL transfer is not associated with a CG resource, then the CG resource for the initial UL transfer is unavailable. Example 3

[0107] In some scenarios, CG resources without RACH can be associated with multiple SSBs. However, only UL authorizations with a configuration having the same SSB index as the SSB corresponding to the TCI state indicated in the LTM cell handover command MAC CE can be used.

[0108] In view of this, embodiments of the present disclosure provide a solution for determining the validity of a CG. In this solution, if the CG is valid, the terminal device 110 can apply the CG for the initial UL transmission.

[0109] In some embodiments, if the index of the SSB selected for the initial UL transmission is the same as the index of the SSB corresponding to the CG, the terminal device 110 can select the SSB and indicate the index of the SSB selected for the initial UL transmission from the higher layer to the lower layer of the terminal device 110. In some embodiments, if the index of the SSB selected for the initial UL transmission is the same as the index of the SSB corresponding to the CG, the terminal device 110 can consider the CG valid. In some embodiments, a valid CG can be used for both the initial UL transmission and the retransmission of the initial UL transmission.

[0110] In some embodiments, if the index of the SSB selected for the initial UL transmission is different from the index of the SSB corresponding to the CG, the terminal device 110 may consider the CG invalid. It should be understood that any combination of the above actions is also possible.

[0111] In this way, CG resources are only initialized or reinitialized when a RACH-based LTM is to be executed, without interfering with the RA-based LTM process. Example 4

[0112] In some scenarios, for LTM cell handovers with skipped RA procedures, dynamic authorization may arrive before the next CG timing. In this case, UE behavior remains unclear.

[0113] In view of this, embodiments of the present disclosure provide a solution for disabling the CG. In this solution, if the initial UL transmission toward the target candidate cell is performed based on dynamic licensing, the terminal device 110 can disable the CG for the initial UL transmission.

[0114] In some embodiments, if the initial UL transmission for LTM is performed based on the UL authorization of the Cell Radio Network Temporary Identifier (C-RNTI) for the MAC entity received on the PDCCH, the terminal device 110 may deactivate the CG for the initial UL transmission. In some embodiments, the terminal device 110 may clear the CG. In some embodiments, the terminal device 110 may suspend the CG. In some embodiments, the terminal device 110 may treat the CG as invalid. In some embodiments, the terminal device 110 may ignore the CG. The above actions may be performed by the MAC layer of the terminal device 110.

[0115] In some embodiments, after the initial UL transmission using the CG for LTM is performed, the terminal device 110 can monitor the PDCCH addressed to the C-RNTI and the configured Scheduled Radio Network Temporary Identifier (CS-RNTI).

[0116] In this way, unwanted CG will not interfere with normal behavior. Example implementation of timer handling for CG

[0117] In some scenarios, during the initial UL transmission using CG, the terminal device can start a CG timer and a CG retransmission timer. However, it is unclear when these two timers will stop, and the UE behavior when these two timers expire is also unclear.

[0118] In view of this, embodiments of this disclosure provide a solution for processing timers for CG. This solution will be described below in conjunction with... Figure 4 Described.

[0119] Figure 4 A schematic diagram of another communication process 400 according to an embodiment of the present disclosure is shown. For purposes of discussion, process 400 will be referred to... Figure 1A Described. Process 400 may involve, for example... Figure 1A The terminal device 110 and network device 120 are shown in the diagram. In this example, network device 120 provides a serving cell (e.g., cell 121) for terminal device 110 and also provides a target candidate cell (e.g., cell 122) for terminal device 110. The serving cell can be an SPCell, PCell, or PSCell of terminal device 110.

[0120] like Figure 4 As shown, terminal device 110 can perform an initial UL transmission towards a target candidate cell that allows LTM based on CG during cell handover.

[0121] During the initial UL transmission, terminal device 110 can initiate a first timer (e.g., configuredGrantTimer) for 420 based on CG and a second timer (e.g., cg-LTM-retransmissionTimer) for retransmission of the initial UL transmission. In this document, the first timer is also referred to as the CG timer, and the second timer is also referred to as the CG retransmission timer.

[0122] refer to Figure 4 Network device 120 can transmit a response 430 to terminal device 110 for the initial UL transmission. When a response is received during the operation of the first timer and the second timer, terminal device 110 can stop the first timer and the second timer 440.

[0123] In some embodiments, terminal device 110 may stop the configured grant timer and CG retransmission timer upon receiving a network response to the initial UL transmission, for example, upon receiving a PDCCH for a newly transmitted UL grant or DL ​​allocation from an addressing MAC entity's C-RNTI scheduling (e.g., the PDSCH associated with the DL allocation may or may not include a contention resolution MACCE). In some embodiments, terminal device 110 may indicate the successful completion of an LTM cell handover from a lower layer (e.g., the MAC layer) to a higher layer (e.g., the RRC layer).

[0124] In some embodiments, if the first timer expires and no response to the initial UL transmission has been received from the network device 120, the terminal device 110 may stop the second timer. That is, if the CG timer expires and no network response to the initial UL transmission has been received, the terminal device 110 may stop the CG retransmission timer.

[0125] In some embodiments, if the first timer (i.e., the CG timer) expires and no response to the initial UL transmission has been received from network device 120, terminal device 110 may transmit a first indication of cell handover failure from the MAC layer to the RRC layer. In some embodiments, if the first timer expires and no response to the initial UL transmission has been received from network device 120, terminal device 110 may transmit a second indication of the first timer expiring from the MAC layer to the RRC layer. In some embodiments, upon receiving at least one of the first or second indications, terminal device 110 may trigger an RRC re-establishment process via its RRC layer.

[0126] In some embodiments, if the second timer (i.e., the CG retransmission timer) expires, the terminal device 110 may perform a retransmission of the initial UL transmission. In some embodiments, if the second timer (i.e., the CG retransmission timer) expires, the terminal device 110 may restart the second timer. It should be understood that any combination of the above actions is also possible.

[0127] So far, a solution for timer handling in CG has been described. In this way, the RRC connection can be restored as quickly as possible.

[0128] It should be understood that, in combination Figures 2 to 4 The operations described in processes 200, 300, and 400 can be performed individually or in any suitable combination. Example implementation of the method

[0129] Accordingly, embodiments of this disclosure provide methods for communication implemented at a terminal device. These methods will be referred to below. Figures 5 to 7Described.

[0130] Figure 5 An example method 500 for communication implemented at a terminal device according to some embodiments of the present disclosure is shown. For example, method 500 can be implemented in, for example, Figure 1A The method is executed at terminal device 110 shown. For the purposes of discussion, method 500 will be referred to below. Figure 1A As described. It should be understood that method 500 may include additional boxes not shown and / or some boxes as shown may be omitted, and the scope of this disclosure is not limited in this respect.

[0131] At box 510, terminal device 110 receives a MAC CE from network device 120, which indicates a cell handover from the first cell to the second cell.

[0132] At frame 520, terminal device 110 determines that the first cell is not a candidate cell for allowing LTM.

[0133] At box 530, terminal device 110 performs an operation including one of the following: determining whether an L2 reset procedure will be performed or not by determining a first identifier value as the identifier value of the serving cell and comparing the first identifier value with a second identifier value for the second cell; performing an L2 reset procedure; skipping an L2 reset procedure; or applying a configuration of an L2 reset procedure included in the LTM configuration (i.e., LTM configuration).

[0134] In some embodiments, terminal device 110 may determine the first identifier value based on the configuration of the first identifier value from network device 120. In some embodiments, terminal device 110 may determine the first identifier value as a default value.

[0135] In some embodiments, if the first identifier value is the same as the second identifier value, the terminal device 110 can determine that the L2 reset process will not be executed. In some embodiments, if the first identifier value is different from the second identifier value, the terminal device 110 can determine that the L2 reset process will be executed.

[0136] In some embodiments, terminal device 110 may determine that the L2 reset process is not executed based on at least one of the following: the first cell is not configured with a first identifier value, or the second cell is not configured with a second identifier value. In some embodiments, terminal device 110 may determine that the L2 reset process will be executed based on at least one of the following: the first cell is not configured with a first identifier value, or the second cell is not configured with a second identifier value.

[0137] Using method 500, if the serving cell or source cell is not an LTM candidate cell, the terminal device can determine whether to perform an L2 reset during LTM cell handover.

[0138] Figure 6 Another example method 600 of communication implemented at a terminal device according to some embodiments of the present disclosure is shown. For example, method 600 can be implemented in, for example, Figure 1A The method is executed at terminal device 110 shown. For the purposes of discussion, method 600 will be referred to below. Figure 1A As described. It should be understood that method 600 may include additional boxes not shown and / or some boxes as shown may be omitted, and the scope of this disclosure is not limited in this respect.

[0139] At box 610, terminal device 110 receives a MAC CE from network device 120, which indicates a cell handover to a target candidate cell that allows LTM.

[0140] At block 620, if the condition is met, terminal device 110 de-enables the configured authorization for the initial uplink transmission toward the target candidate cell during cell handover. In some embodiments, if a random access procedure will be performed for cell handover, terminal device 110 may de-enable the configured authorization. In some embodiments, if the SSB selected for the initial uplink transmission is not configured with authorization for configuration, terminal device 110 may de-enable the configured authorization. In some embodiments, if the initial uplink transmission is performed based on dynamic authorization, terminal device 110 may de-enable the configured authorization.

[0141] In some embodiments, if the random access procedure for cell handover is skipped, terminal device 110 may apply authorization for the configuration of the initial uplink transmission. In some embodiments, if the configured authorization is valid, terminal device 110 may apply authorization for the configuration of the initial uplink transmission.

[0142] In some embodiments, the terminal device 110 may apply the configured authorization by at least one of the following: the terminal device's RRC layer configuring the authorization for the initial uplink transmission of the second cell; the terminal device's MAC layer storing the configured authorization; or the terminal device's MAC layer initializing or re-initializing the configured authorization.

[0143] In some embodiments, the terminal device may be able to apply the configured authorization for both the initial uplink transmission and the retransmission of the initial uplink transmission.

[0144] In some embodiments, terminal device 110 can enable the configured authorization by clearing the configured authorization. In some embodiments, terminal device 110 can enable the configured authorization by suspending the configured authorization. In some embodiments, terminal device 110 can enable the configured authorization by treating the configured authorization as invalid. In some embodiments, terminal device 110 can enable the configured authorization by ignoring the configured authorization.

[0145] In some embodiments, if the index of the SSB selected for the initial uplink transmission is the same as the index of the SSB corresponding to the configured authorization, the terminal device 110 may perform an operation including at least one of the following: selecting an SSB; indicating the index of the SSB selected for the initial uplink transmission from a higher layer of the terminal device to a lower layer; or treating the configured authorization as valid.

[0146] Using method 600, the CG resources for the initial uplink transmission of LTM can be appropriately processed.

[0147] Figure 7 Further example method 700 of communication implemented at a terminal device according to some embodiments of the present disclosure is shown. For example, method 700 can be implemented as follows: Figure 1A The method is executed at terminal device 110 shown. For the purposes of discussion, method 700 will be referred to below. Figure 1A As described. It should be understood that method 700 may include additional boxes not shown and / or some boxes as shown may be omitted, and the scope of this disclosure is not limited in this respect.

[0148] At box 710, terminal device 110 performs an initial uplink transmission toward a target candidate cell that allows LTM based on the configured authorization during cell handover.

[0149] At box 720, terminal device 110 starts a first timer for the configured authorization and a second timer for retransmission of the initial uplink transmission based on the configured authorization.

[0150] At box 730, terminal device 110 determines that the response to the initial uplink transmission was received from the network device providing the target candidate cell during the operation of the first timer and the second timer.

[0151] At frame 740, terminal device 110 stops the first timer and the second timer.

[0152] In some embodiments, if the first timer expires and no response to the initial uplink transmission has been received from the network device 120, the terminal device 110 may perform an operation including at least one of the following: stopping the second timer; transmitting at least one of the following from the MAC layer of the terminal device 110 to the RRC layer: a first indication of cell handover failure or a second indication of the first timer expiring; or triggering an RRC re-establishment process by the RRC layer of the terminal device 110 upon receiving at least one of the first or second indications.

[0153] In some embodiments, if the second timer expires, the terminal device 110 may perform at least one of the following operations: retransmit the initial uplink transmission; or restart the second timer.

[0154] Using method 700, the RRC connection can be restored as quickly as possible.

[0155] It should be understood that the operations in methods 500 to 700 correspond to the combination Figures 2 to 4 The operation being described will not be repeated here for the sake of brevity. Example implementation of the device

[0156] Figure 8 This is a simplified block diagram of a device 800 suitable for implementing embodiments of the present disclosure. Device 800 can be considered as a further example implementation of terminal device 110 or network device 120 as shown in FIG. 1. Therefore, device 800 can be implemented at or as a part of terminal device 110 or network device 120.

[0157] As shown, device 800 includes a processor 810, a memory 820 coupled to the processor 810, a suitable transceiver 840 coupled to the processor 810, and a communication interface coupled to the transceiver 840. The memory 810 stores at least a portion of program 830. The transceiver 840 can be used for bidirectional communication or demand-based unidirectional communication. The transceiver 840 may include at least one of a transmitter 842 or a receiver 844. The transmitter 842 and receiver 844 may be functional modules or physical entities. The transceiver 840 has at least one antenna to facilitate communication, although in practice, the access node mentioned in this application may have several antennas. The communication interface can represent any interface required for communication with other network elements, such as the X2 / Xn interface for bidirectional communication between eNB / gNB, the S1 / NG interface for communication between the Mobility Management Entity (MME) / Access and Mobility Management Function (AMF) / SGW / UPF and eNB / gNB, the Un interface for communication between eNB / gNB and Relay Node (RN), or the Uu interface for communication between eNB / gNB and terminal equipment.

[0158] Program 830 is assumed to include program instructions that, when executed by the associated processor 810, enable device 800 to operate according to the instructions shown in Figures 1 to 14 herein. Figure 7 The embodiments of this disclosure discussed herein operate. These embodiments can be implemented by computer software executable by processor 810 of device 800, or by hardware, or by a combination of software and hardware. Processor 810 can be configured to implement various embodiments of this disclosure. Furthermore, a combination of processor 810 and memory 820 can form a processing unit 850 suitable for implementing various embodiments of this disclosure.

[0159] Memory 820 can be of any type suitable for a local technology network and can be implemented using any suitable data storage technology, such as, as non-limiting examples, non-transient computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. Although only one memory 820 is shown in device 800, several physically different memory modules may exist in device 800. Processor 810 can be of any type suitable for a local technology network and, as non-limiting examples, may include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 800 may have multiple processors, such as application-specific integrated circuit chips that are time-dependent on a clock synchronized with the main processor.

[0160] In some embodiments, the terminal device includes a circuit system configured to: receive a MAC CE from a network device, the MAC CE indicating a cell handover from a first cell to a second cell; and, based on the determination that the first cell is not a candidate cell for LTM, perform an operation including one of the following: determining whether an L2 reset procedure will be performed or not by determining a first identifier value as the identifier value of the serving cell and comparing the first identifier value with a second identifier value for the second cell; performing an L2 reset procedure; skipping an L2 reset procedure; or applying a configuration of an L2 reset procedure included in the LTM configuration.

[0161] In some embodiments, the terminal device includes a circuitry configured to: receive a MAC CE from a network device, the MAC CE indicating a cell handover to a target candidate cell that allows LTM; and to enable or disable authorization for the configuration of an initial uplink transmission toward the target candidate cell during the cell handover based on at least one of the following: a random access procedure will be performed for the cell handover; the synchronization signal block (SSB) selected for the initial uplink transmission is not configured for authorization; or the initial uplink transmission is performed based on dynamic authorization.

[0162] In some embodiments, the terminal device includes a circuit system configured to: in cell handover, perform an initial uplink transmission toward a target candidate cell that allows LTM based on a configured authorization; start a first timer for the configured authorization and a second timer for retransmission of the initial uplink transmission based on the configured authorization; and stop the first timer and the second timer based on a determination that a response to the initial uplink transmission has been received from the network device providing the target candidate cell during the operation of the first timer and the second timer.

[0163] As used herein, the term "circuit system" can refer to hardware circuitry and / or a combination of hardware circuitry and software. For example, a circuit system can be a combination of analog and / or digital hardware circuitry and software / firmware. As a further example, a circuit system can be any part of a hardware processor with software, including multiple digital signal processors, software, and multiple memories that work together to enable a device (such as a terminal device or network device) to perform various functions. In yet another example, a circuit system can be hardware circuitry and / or a processor (such as a microprocessor or a portion thereof) that requires software / firmware to operate, but the software may be absent when it is not required to operate. As used herein, the term circuit system also encompasses the implementation of only hardware circuitry or the processor(s) or a portion thereof and its (or their) accompanying software and / or firmware.

[0164] In general, the various embodiments of this disclosure can be implemented as hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects can be implemented as hardware, while others can be implemented as firmware or software executable by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of this disclosure are shown and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, as non-limiting examples, the blocks, apparatuses, systems, techniques, or methods described herein can be implemented as hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0165] This disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as those included in a program module, that are executed in a device on a target real or virtual processor to perform actions as shown above with reference to Figures 1 to 1. Figure 7 The described process or method. Generally, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform specific tasks or implement specific abstract data types. In various embodiments, the functionality of a program module can be combined or split among program modules as needed. The machine-executable instructions for a program module can be executed on a local or distributed device. In a distributed device, a program module can reside on both local and remote storage media.

[0166] Program code used to perform the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0167] The aforementioned program code can be embodied on a machine-readable medium, which can be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples of machine-readable storage media will include electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0168] Furthermore, although the operations are depicted in a specific order, this should not be construed as requiring that these operations be performed in the specific order shown or sequentially, or requiring that all shown operations be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of this disclosure, but rather as a description of features that may be specific to particular embodiments. Certain features described in the context of a single embodiment may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0169] Although this disclosure has been described in language specific to structural features and / or methodological actions, it should be understood that this disclosure as defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as exemplary forms of implementing the claims.

Claims

1. A terminal device, comprising: The processor is configured to cause the terminal device to: Receive a Media Access Control (MAC) control element (CE) from the network device, the MAC CE indicating a cell handover from a first cell to a second cell; as well as Based on the determination that the first cell is not a candidate cell for mobility that is allowed to be triggered by Layer 1 or Layer 2, perform an operation including one of the following: By determining the first identifier value as the identifier value of the serving cell and comparing the first identifier value with the second identifier value for the second cell, it is determined whether the Layer 2 reset process will be performed or not. Execute the layer 2 reset process; Skip the layer 2 reset process; or The application is included in the configuration of the Layer 2 reset process in the configuration of mobility triggered by Layer 1 or Layer 2.

2. The terminal device according to claim 1, wherein the terminal device is configured to determine the first identifier value by: The first identifier value is determined based on the configuration of the first identifier value from the network device; or The first identifier value is set as the default value.

3. The terminal device of claim 1, wherein the terminal device is configured to determine whether the layer 2 reset process will be performed or not by: Based on the determination that the first identifier value and the second identifier value are the same, it is determined that the layer 2 reset process will not be executed; or Based on the determination that the first identifier value and the second identifier value are different, it is determined that the layer 2 reset process will be executed.

4. The terminal device according to claim 1, wherein the terminal device is further configured to: The layer 2 reset process is not performed based on at least one of the following: The first cell is not configured with the first identifier value, or The second cell was not configured with the second identifier value; or The layer 2 reset process will be performed based on at least one of the following: The first cell is not configured with the first identifier value, or The second cell was not configured with the second identifier value.

5. A terminal device, comprising: The processor is configured to cause the terminal device to: Receive a Media Access Control (MAC) control element (CE) from a network device, the MAC CE indicating a cell handover to a target candidate cell that allows mobility triggered by Layer 1 or Layer 2; as well as Authorization for the configuration of the initial uplink transmission toward the target candidate cell during the cell handover is enabled or disabled based on at least one of the following: The random access procedure will be performed for the handover of the cell; The synchronization signal block (SSB) selected for the initial uplink transmission was not configured with authorization for the configuration; or The initial uplink transmission is performed based on dynamic authorization.

6. The terminal device according to claim 5, wherein the terminal device is further configured to: Based on the determination in the random access procedure that the cell handover has been skipped, the authorization for the initial uplink transmission configuration is applied; or Based on the valid determination of the authorization of the configuration, the authorization of the configuration for the initial uplink transmission is applied.

7. The terminal device of claim 6, wherein the terminal device is configured to apply the authorization of the configuration by at least one of the following: The Radio Resource Control (RRC) layer of the terminal device configures the authorization of the configuration for the initial uplink transmission for the second cell; The authorized configuration is stored by the MAC layer of the terminal device; or The authorization of the configuration is initialized or re-initialized by the MAC layer of the terminal device.

8. The terminal device of claim 6, wherein the terminal device is configured to apply the authorization of the configuration by: The authorization of the configuration is applied to both the initial uplink transmission and the retransmission of the initial uplink transmission.

9. The terminal device of claim 5, wherein the terminal device is configured to disable the authorization of the configuration by at least one of the following: Clear the authorization configured above; Suspend the authorization of the configuration; The authorization of the configuration is deemed invalid; or Ignore the authorization of the configuration.

10. The terminal device according to claim 5, wherein the terminal device is further configured to: Based on the determination that the index of the SSB selected for the initial uplink transmission is the same as the index of the authorized SSB corresponding to the configuration, perform an operation including at least one of the following: Select the SSB; The index of the SSB selected for the initial uplink transmission is indicated from the higher layer of the terminal device to the lower layer; or The authorization of the configuration is considered valid.

11. A terminal device, comprising: The processor is configured to cause the terminal device to: During cell handover, the initial uplink transmission toward the target candidate cell that allows Layer 1 or Layer 2 triggered mobility is performed based on the configured authorization. Based on the authorization configured, start a first timer for the authorization configured and a second timer for the retransmission of the initial uplink transmission; as well as Based on the determination that a response to the initial uplink transmission is received from the network device providing the target candidate cell during the operation of the first and second timers, the first and second timers are stopped.

12. The terminal device according to claim 11, wherein the terminal device is further configured to: Based on the determination that the first timer has expired and no response to the initial uplink transmission has been received from the network device, perform an operation including at least one of the following: Stop the second timer; The terminal device transmits at least one of the following from its Media Access Control (MAC) layer to its Radio Resource Control (RRC) layer: a first indication of a failed cell handover, or a second indication of the expiration of the first timer; or Upon receiving at least one of the first instruction or the second instruction, the RRC re-establishment process is triggered by the RRC layer of the terminal device.

13. The terminal device according to claim 11, wherein the terminal device is further configured to: Based on the determination of the expiration of the second timer, perform an operation including at least one of the following: Perform the retransmission of the initial uplink transmission; or Restart the second timer.

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