Uplink grant control

Abstract

Exemplary embodiments of the present disclosure relate to uplink grant control In an aspect, terminal device determines, after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and based on determining that the condition for triggering the C-LTM is met, transmits a request for dynamic grant (DG) activation.

Description

UPLINK GRANT CONTROLFIELD

[0001] Embodiments of the present disclosure generally relate to the field of communication, and in particular, to devices, methods, apparatuses and a computer readable storage medium for uplink grant control.BACKGROUND

[0002] A communication network can be seen as a facility that enables communications between two or more communication devices, or provides communication devices access to a data network. A mobile or wireless communication network is one example of a communication network.

[0003] Such communication networks operate in according with standards such as those provided by 3GPP (Third Generation Partnership Project) or ETSI (European Telecommunications Standards Institute). Examples of standards are the so-called 5G (5th Generation) standards provided by 3GPP. The 3GPP has agreed that the terminal device can perform a timing advance estimation for candidate cells after configured by the network device.SUMMARY

[0004] In general, example embodiments of the present disclosure provide devices, methods, apparatuses and a computer readable storage medium for uplink grant control.

[0005] In a first aspect, there is provided a terminal device. The terminal device may comprise: at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: determine, after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and based on determining that the condition for triggering the C-LTM is met, transmit a request for configured grant (CG) activation.

[0006] In a second aspect, there is provided a network device. The network device may comprise: at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: receive after an early synchronization procedure, a request for configured grant (CG) activation in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C- LTM) for a candidate cell of the first network device is met.

[0007] In a third aspect, there is provided a method. The method may comprise: determining, after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C- LTM) for a candidate cell of a first network device is met; and based on determining that the condition for triggering the C-LTM is met, transmitting a request for configured grant (CG) activation.

[0008] In a fourth aspect, there is provided a method. The method may comprise: receiving after an early synchronization procedure, a request for configured grant (CG) activation in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0009] In a fifth aspect, there is provided an apparatus. The apparatus may comprise: means for determining, after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and means for based on determining that the condition for triggering the C-LTM is met, transmitting a request for configured grant (CG) activation.

[0010] In a sixth aspect, there is provided an apparatus. The apparatus may comprise: means for receiving after an early synchronization procedure, a request for configured grant (CG) activation in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0011] In a seventh aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to third or fourth aspect.

[0012] In an eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to perform at least the method according to third or fourth aspect.

[0013] In a ninth aspect, there is provided a terminal device. The terminal device may comprise: determining circuitry configured to determine, after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and transmitting circuitry configured to: based on determining that the condition for triggering the C-LTM is met, transmit a request for configured grant (CG) activation.

[0014] In a tenth aspect, there is provided a network device. The network device may comprise receiving circuitry configured to receive after an early synchronization procedure, a request for configured grant (CG) activation in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0015] In an eleventh aspect, there is provided a terminal device. The terminal device may comprise: at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: determine, after an early synchronization procedure, whether a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and based on determining that the condition for triggering the C-LTM is met, transmit, a request for dynamic grant (DG) activation.

[0016] In a twelfth aspect, there is provided a network device. The network device may comprise: at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: receive, after an early synchronization procedure, a request for dynamic grant (DG) activation, in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0017] In a thirteenth aspect, there is provided a method. The method may comprise: determining, after an early synchronization procedure, whether a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and based on determining that the condition for triggering the C-LTM is met, transmitting, a request for dynamic grant (DG) activation.

[0018] In a fourteenth aspect, there is provided a method. The method may comprise: receiving, after an early synchronization procedure, a request for dynamic grant (DG) activation, in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0019] In a fifteenth aspect, there is provided an apparatus. The apparatus may comprise: means for determining, after an early synchronization procedure, whether a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and means for based on determining that the condition for triggering the C-LTM is met, transmitting, a request for dynamic grant (DG) activation.

[0020] In a sixteenth aspect, there is provided an apparatus. The apparatus may comprise: means for receiving, after an early synchronization procedure, a request for dynamic grant (DG) activation, in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0021] In a seventeenth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to third or fourth aspect.

[0022] In an eighteenth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to perform at least the method according to third or fourth aspect.

[0023] In a nineteenth aspect, there is provided a terminal device. The terminal device may comprise: determining circuitry configured to determine, after an early synchronization procedure, whether a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; transmitting circuitry configured to: based on determining that the condition for triggering the C-LTM is met, transmit, a request for dynamic grant (DG) activation.

[0024] In a twentieth aspect, there is provided a network device. The network device may comprise receiving circuitry configured to receive, after an early synchronization procedure, a request for dynamic grant (DG) activation, in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0025] It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0027] Fig. 1 illustrates an example network environment in which example embodiments of the present disclosure may be implemented;

[0028] Fig. 2A illustrates an example signaling process for uplink grant control according to some embodimentsof the present disclosure;

[0029] Fig. 2B illustrates an example signaling process for uplink grant control according to some embodiments of the present disclosure;

[0030] Fig. 3 illustrates another example signaling process during the preparation phase according to some embodiments of the present disclosure;

[0031] Fig. 4A to Fig.4C illustrate another example signaling process during the C-LTM execution phase according to some embodiments of the present disclosure;

[0032] Fig. 5A illustrates a flowchart of an example method implemented at a terminal device in accordance with some example embodiments of the present disclosure;

[0033] Fig. 5B illustrates a flowchart of an example method implemented at a terminal device in accordance with some example embodiments of the present disclosure;

[0034] Fig. 6A illustrates another flowchart of an example method implemented at a network device in accordance with some example embodiments of the present disclosure;

[0035] Fig. 6B illustrates another flowchart of an example method implemented at a network device in accordance with some example embodiments of the present disclosure;

[0036] Fig. 7 illustrates a simplified block diagram of a device that is suitable for implementing some example embodiments of the present disclosure; and

[0037] Fig. 8 illustrates a block diagram of an example of a computer-readable medium in accordance with some example embodiments of the present disclosure.

[0038] Throughout the drawings, the same or similar reference numerals represent the same or similar element.DETAILED DESCRIPTION

[0039] Principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein may be implemented in various manners other than the ones described below.

[0040] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which the present disclosure belongs.

[0041] References in the present disclosure to "one embodiment,” "an embodiment,” "an example embodiment,” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with otherembodiments whether or not explicitly described.

[0042] It may be understood that although the terms "first” and "second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and / or” includes any and all combinations of one or more of the listed terms.

[0043] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. 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. It will be further understood that the terms "comprises”, "comprising”, "has”, "having”, "includes” and / or "including”, when used herein, specify the presence of stated features, elements, and / or components etc., but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. As used herein, "at least one of the following: ” and "at least one of ” and similar wording, where the list of two or more elements are joined by "and” or "or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0044] As used in this application, the term "circuitry” may refer to one or more or all of the following:(a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and(b) combinations of hardware circuits and software, such as (as applicable):(I) a combination of analog and / or digital hardware circuit(s) with software / fi rmware and(II) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s) that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0045] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0046] As used herein, the term "communication network” refers to a network following any suitable communication standards, such as long term evolution (LTE), LTE-advanced (LTE-A), wideband code division multiple access (WCDMA), high-speed packet access (HSPA), narrow band Internet of things (NB-loT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, thethird generation (3G), the fourth generation (4G), 4.5G, the fifth generation (5G) communication protocols, and / or beyond. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

[0047] As used herein, the term "network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP), for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR NB (also referred to as a gNB), a remote radio unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

[0048] The term "terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. In the following description, the terms "terminal device”, "communication device”, "terminal”, "user equipment” and "UE” may be used interchangeably.

[0049] When a user equipment (UE) moves from one cell to another cell, at some point a serving cell change needs to be performed. In some cases, the serving cell change is done by explicit radio resource control (RRC) reconfiguration signaling to trigger the synchronization of target cell based on L3 measurements report. It leads to longer latency, larger overhead, and longer interruption time than beam level mobility. Therefore, in 3GPP Release 18, a new work item on further new radio (NR) mobility enhancements, named as layer 1 (L1) I layer 2 (L2)-triggered mobility (LTM), was approved to enable a serving cell change via L1 / L2 signaling, in order to reduce the latency, overhead and interruption time.

[0050] Rel-18 LTM (L1 / L2 triggered mobility) is a mobility procedure where the network configures the UE with up to 8 candidate cells, and eventually sends a cell switch command to the UE to perform cell switch to one of those cells. Cell switch decision may be based on L1 or L3 measurements reported by the UE. One of the key goals of LTM was to reduce the interruption caused by the cell switch from the L3 handover. The reduction of the interruption caused by the cell switch is achieved through different early procedures: early DL synchronizationthrough early transmission configuration indication (TCI) state activation; early UL synchronization through physical downlink control channel (PDCCH) ordered random access channel (RACH) or UE based TA estimation; or early abstract syntax notation one (ASN.1) decoding and validity check.

[0051] L3 conditional handover is a procedure where the network configures the UE with one or more signal thresholds-based conditions for one or more cells. The UE evaluates the conditions and at the event of a condition for a cell becoming met, executes conditional handover without a handover command to this cell.

[0052] Rel-19 will introduce conditional LTM as an enhancement to the Rel-18 LTM procedure. In conditional LTM, the UE will autonomously execute cell switch to one of the candidate cells based on network-configured conditions. As the 3GPP work for conditional LTM has not yet started, the details of the full procedure, including the preparation steps, are still open.

[0053] In view of the above, some embodiments of the present disclosure propose a solution for cell switch condition evaluation. Specifically, in some embodiments of the present disclosure, the terminal device determines, after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and based on determining that the condition for triggering the C-LTM is met, transmits, a request for configured grant (CG) activation.

[0054] In some embodiments of the present disclosure, the terminal device determines, after an early synchronization procedure, whether a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C- LTM) for a candidate cell of a first network device is met; and based on determining that the condition for triggering the C-LTM is met, transmits, a request for dynamic grant (DG) activation.

[0055] For illustrative purposes, principle and example embodiments of the present disclosure will be described below with reference to Figs. 1-8. However, it is to be noted that these embodiments are given to enable the skilled in the art to understand inventive concepts of the present disclosure and implement the solution as proposed herein, and not intended to limit scope of the present application in any way.

[0056] Fig. 1 illustrates an example network environment 100 in which example embodiments of the present disclosure may be implemented. The environment 100, which may be a part of a communication network, includes terminal devices and network devices.

[0057] As illustrated in Fig. 1 , the communication network 100 may include a terminal device 110 (hereinafter may also be referred to as a user equipment (UE) 110). The communication network 100 may further include a network device 120, which can be a source distributed unit (DU) providing a plurality of cells, and one of them can be a serving cell (for example, cell 120-1) for serving the terminal device 110 now. The communication network 100 may further include another network device 130, which can be a target DU providing a plurality of candidate cells, and one of the candidate cells may be a target cell (for example, cell 130-1) to be switched to by the terminal device 110. The communication network 100 may further include still another network device 140, which can be the centralized unit (CU) for managing the source DU and the target DU.

[0058] As shown in Fig. 1 when the UE 110 moves between different cells belonging to different DUs within a same CU. In short, this scenario is called as inter-DU mobility. As shown in Fig. 1 , the serving cell 120-1 belongsto the network device 120, and the target cell 130-1 belongs to the network device 130, and the terminal device 110 moves from the cell 120-1 to the cell 130-1. It should be understood that each DU may have many cells, and only one cell is shown for illustration, for example, there are several candidate cells for the target DU, and only one cell as a target cell is shown for the purpose of illustration.

[0059] It is to be understood that the number of network devices and terminal devices is given only for the purpose of illustration without suggesting any limitations. The system 100 may include any suitable number of network devices and / or terminal devices adapted for implementing embodiments of the present disclosure. Although not shown, it would be appreciated that one or more terminal devices may be located in the environment 100.

[0060] Communications in the network environment 100 may be implemented according to any proper communication protocol(s), comprising, but not limited to, the third generation (3G), the fourth generation (4G), the fifth generation (5G) or beyond, wireless local network communication protocols such as institute for electrical and electronics engineers (IEEE) 802.11 and the like, and / or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: multiple-input multiple-output (MIMO), orthogonal frequency division multiplexing (OFDM), time division multiplexing (TDM), frequency division multiplexing (FDM), code division multiplexing (CDM), Bluetooth, ZigBee, and machine type communication (MTC), enhanced mobile broadband (eMBB), massive machine type communication (mMTC), ultra-reliable low latency communication (URLLC), carrier aggregation (CA), dual connection (DC), and new radio unlicensed (NR-U) technologies.

[0061] For Rel-19 conditional LTM (C-LTM), procedures defined in Rel-18 LTM, which was based on network- triggered cell switch, may have to be enhanced to support UE-autonomous cell switch triggering. In addition, although only intra-CU LTM will be supported in Rel-19, further enhancements of the LTM feature to support conditional inter-CU LTM may follow in subsequent releases.

[0062] All the details of C-LTM are up to Rel-19 discussions and agreements. However, at least the baseline framework of conditional handover (CHO) will be considered as a starting point, i.e. the UE will be configured with one or more (L1 or L3 measurement based) conditions for one or more candidate cells. The conditions can be provided in the common LTM configuration or can be candidate specific. At the event of such condition becoming met, the UE shall execute conditional LTM cell switch to a candidate cell for which the condition was met. How the conditions are defined and how the early preparation steps, DL and UL synchronization, will work for C-LTM are still open. As an example, these can be network proprietary. As another example, these can be determined based on the measurement the UE sends to the network when the network has decided to configure C-LTM towards the UE.

[0063] With C-LTM, allowing the UE to evaluate all configured conditions continuously and autonomously trigger HO based on the evaluation may be problematic as it weakens (and potentially removes) network control of the switching procedures. This makes it difficult for the NW to perform different procedures (e.g., load balancing). Moreover, depending on the underlying radio conditions, the UE can end up executing too frequent cell switches (e.g., when the UE is at cell edge); this is even more pronounced in case the UE is allowed to perform subsequentC-LTM. Moreover, depending on the frequency of the subsequent LTM switches, it might even be difficult for the NW to ensure that path switch is completed (this becomes a problem particularly in inter-CU LTM cases).

[0064] In addition to the abovementioned issues, when considering fully UE-based RACH-less C-LTM cell switching, NW does not know how / when to schedule an UL grant. A trivial approach would be that NW always schedules an UL grant, however this would be highly suboptimal from NW viewpoint (allocating too many UE- specific grants for multiple candidate cells and monitoring corresponding UE transmission for UL grant across all the LTM candidates and all time slots can be quite resource intensive). This problem would be further aggravated when multiple grants need to be configured for different beams or directions, especially in FR2-based systems. At least one aim of this application is to introduce a mechanism that enables more efficient coordination between UE and NW for the activation of UL grant, especially for RACH-less cell switching.

[0065] In view of the foregoing, an example signaling process200A for uplink grant control in conditional LTM (C-LTM) according to some embodiments of the present disclosure will be described with referent to Fig. 2A hereinafter. For the purpose of discussion, the communication process 200A will be described with reference to Fig. 1. It would be appreciated that although the communication process 200A has been described referring to the network environment 100 of Fig. 1, this communication process 200A may be likewise applied to other similar communication scenarios. It should be appreciated that the terminal device 201 is an example of the terminal device 110 of Fig. 1 and the first network device 202 is an example of the network device 130 (i.e. a target DU) of Fig. 1.

[0066] As shown in Fig. 2A, the terminal device 201 determines (205), after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met. Based on determining that the condition for triggering the C-LTM is met, the terminal device 201 transmits (210) a request for configured grant (CG) activation. The request for CG activation may be directly or via some other network entity transmitted to the first network device, as shown by the dotted line. The network device 202 receives (215) the request for CG activation. In some embodiments, the request for CG activation comprises a CFRA preamble, a scheduling request, or both of them.

[0067] In some embodiments, the request for CG activation is transmitted from the terminal device to a centralized unit which forwards the request for CG activation to the first network device, the request for CG activation is transmitted from the terminal device to a second network device serving the terminal device. In this event, the second network device forwards the request for CG activation to the centralized unit, and the centralized unit forwards the request for CG activation to the first network device. Alternatively, the request for CG activation is transmitted from the terminal device to the first network device.

[0068] For example, in some embodiments, UE sends CG activation request to CU. Alternatively, UE sends CG activation request to S-DU, and S-DU sends CG activation request to CU and CU sends CG activation request to T-DU, and then, the T-DU activates the CG, and the T-DU sends CG to CU. CU sends CG to S-DU which forwards it to the UE. For example, UE can inform S-DU that it is getting ready to trigger a cell switch. S-DU informs CU that UE is getting ready to trigger a cell switch. CU informs T-DU to activate the CG. T-DU informs CU that it has activated the CG. CU informs S-DU that the CG is activated. S-DU may inform UE that CG isactivated. For example, the S-DU may use DCI, e.g. PDCCH order, or MAC signalling to inform UE that T-DU has activated the CG. In another case, CU does not inform UE that CG is activated, but UE sends CG to T-DU after some amount of time.

[0069] Alternatively, UE sends CG activation request to T-DU, and T-DU activates CG and sends CG to UE.

[0070] Alternatively, UE sends CG activation request to T-DU, and T-DU activates CG, and sends CG to CU, and CU sends CG to S-DU, and S-DU sends CG of the T-DU to the UE, and UE receives the CG of the T-DU and sends it to T-DU. For example, the S-DU may use DCI, e.g. PDCCH order, or MAC signalling to send the UL grant to the UE. For example, UL grant may be CG. As another example, the UL grant may be DG. For example, UE sends CFRA preamble to T-DU. T-DU activates CG. T-DU informs CU which informs S-DU that CG is activated. S-DU can inform the UE that T-DU has activated CG.

[0071] In some embodiments, the terminal device waits for a predefined number of slots or a predefined time period after transmitting the request for CG activation; and transmits for an allowed number of times, to the first network device, a CG transmission for an allowed number of times, after the predefined number of slots or the predefined of time period, without permission from the first network device to send the CG transmission. In some embodiments, if the CG transmission is not successful, the terminal device falls back to RACH-based RA. For example, UE sends CFRA preamble and waits for a predefined number of slots, or a certain amount of time and then attempts CG transmission. If CG transmissions is not successful (e.g., UE exhausts maximal allowed number of CG transmissions, timer associated with sending CG expires), UE falls back to RACH-based RA. Similarly, if the UE observes that its TA value is no longer valid, UE again falls back to RACH-based RA.

[0072] In some embodiments, the terminal device may determine whether or not the CG is activated by monitoring a CG activation indication, from the first network device, the second network device serving the terminal device, or the centralized unit, within a predefined number of slots or a predefined of time period that is configured by the first network device and comprised in a C-LTM configuration. That is to say, as mentioned above, the CG activation indication can be transmitted from the target DU, the source DU, or the source CU to the terminal device. For example, UE sends CFRA preamble and waits to receive permission to use CG from source DU, or the target UD, or the CU.

[0073] In some embodiments, the terminal device 201 transmits a CG transmission to the first network device, based on determining that the CG is activated; or retransmits a further request for CG activation for a predefined number of times that is configured by the first network device, based on determining that the CG is not activated. For example, if UE observes that target DU has received the CFRA preamble (e.g., PDCCH, MAC CE or any other indication indicating CG activation (not always needed to include uplink grant), UE sends CG. If UE observes that target DU has not received the CFRA preamble (e.g., target DU is not scheduling CG transmission), UE retries sending CFRA preamble.

[0074] For example, in some embodiments, the network device (for example, the source CU) determines a C- LTM configuration; and transmits the C-LTM configuration. The C-LTM configuration comprises a measurement threshold which is to be used by the terminal device to determine whether the condition for triggering the C-LTM is met; a number of slots between two adjacent requests for CG activation; or an allowed number of times that is tobe used by the terminal device to transmit the request for CG activation; or any combination of these options. In some embodiments, the terminal device determines whether the condition for triggering the C-LTM for the candidate cell of the first network device is met by: determining whether a measurement result is above a measurement threshold configured by the first network device and comprised in a C-LTM configuration.

[0075] For example, NW configures the following for the UE, conditions on when to inform the NW that UE is planning to trigger cell switch (e.g., UE sends CFRA preamble to inform the NW that it is preparing to trigger cell switch when a pre-defined threshold is met). In one embodiment, the UE sends the CFRA preamble when the conditional cell change condition is met. In another embodiment, the UE sends the preamble when a condition that is offset to the conditional cell execution condition by X dB is met, so that it may receive confirmation from the NW early on and be ready to use the CG upon execution of the cell switch.

[0076] In some embodiments, the CG activation indication is received, from the first network device (for example, the target DU), by receiving an indication from the first network device for indicating that the CG is activated. In some embodiments, the CG activation indication is received from the second network device (for example, source CU) serving the terminal device. In this situation, the CG activation indication is transmitted to the second network device from the first network device via the centralized unit.

[0077] In some embodiments, the CG activation indication is received by or via a first PDCCH order, a first dedicated media access control-control element (MAC-CE), a first TCI state activation command, a first TA value, or any combination of them. Alternatively or additionally, the CG activation indication is received by indicating the terminal device to perform early decoding of configuration of the candidate cell pertaining to the first network device. In some embodiments, the first TCI state activation command is used to indicate the terminal device to deactivate one or more TCI states excluding the TCI state used by the terminal device to transmit the CG transmission.

[0078] For example, the S-DU informs UE to send CG to T-DU. This can be through a PDCCH order, dedicated MAC CE, or implicitly, by sending a TCI state activation command or a TA value. In another implementation, the S-DU can send TCI state deactivation command, instructing the UE to deactivate all TCI states but the one it should use for sending the CG. In yet another implementation, S-DU can indicate to the UE to perform early decoding of the configuration of the candidate cell pertaining to the target DU. This implicitly also indicates to the UE that target DU is waiting for the UE to send the UL grant. It should be appreciated that other network device may also inform UE to send CG to T-DU in the same way.

[0079] In some embodiments, the CG activation indication is received from the centralized unit (CU), and the CG activation indication is transmitted to the CU from the first network device. In some embodiments, the CG activation indication is received from the CU via an RRC signaling.

[0080] In some embodiments, the CG activation indication comprises information on a periodicity of the CG scheduling, a slot for the terminal device to send UL grant data, or both of them.

[0081] In some embodiments, the terminal device 201 further receive, from a second network device serving the terminal device, a message indicating the terminal device to retransmit the request for CG activation via a second PDCCH order, a second MAC-CE, a second TCI state activation command, a second TA value, or any combination of them. For example, S-DU can either inform target, or request UE to send CFRA preamble again toT-DU. This can be at least through a PDCCH order, dedicated MAC CE, or implicitly, by sending a TCI state activation command, a TA value or a combination of the aforementioned alternatives.

[0082] In some embodiments, the terminal device is further caused to: transmit, to a second network device serving the terminal device, or to a centralized unit via the second network device, an indication that the terminal device has attempted to transmit the request for CG activation to the first network device. For example, the indication that the terminal device has attempted to transmit the request for CG activation to the first network device comprises a specific cell to which the terminal device has transmitted the request for CG activation. Alternatively or additionally, the indication comprises a first TCI state that has been activated. Alternatively or additionally, the indication comprises a second TCI state that is relevant for the specific cell to which the terminal device has transmitted the request for CG activation. Alternatively or additionally, the indication comprises multiple activated or deactivated TCI states including indications for multiple cells for which terminal device has transmitted the request for CG activation. Alternatively or additionally, the indication comprises an indicator in a measurement report from the terminal device to the second network device serving the terminal device.

[0083] In some embodiments, the request of CG activation comprises a preamble used for TA acquisition or a dedicated preamble indicated to the terminal device for uplink grant activation. In some embodiments, the dedicated preamble indicated to the terminal device for uplink grant activation comprises a preamble provided to the terminal device for random access channel (RACH)-based access to the first network device. In some embodiments, the terminal device transmits the request for CG activation on a RACH occasion associated with a selected synchronization signal block (SSB) which is selected based on an early downlink (DL) or uplink (UL) procedure or based on a latest DL measurement, and the selected SSB is associated with an activated or indicated transmission configuration indication (TCI) state, an early timing advance (TA) acquisition procedure, a terminal device-based TA estimation, or a physical downlink control channel (PDCCH)-ordered RACH procedure.

[0084] In some embodiments, the terminal device falls back to RACH-based random access based on determining that a CG transmission is unsuccessful, a predefined number of times for retransmitting the request for CG activation is exhausted, a timing advance value is no longer valid, or any combination thereof. For example, UE repeats this procedure until a maximum number of TX is allowed. Otherwise, UE falls back to RACH-based RA. Similarly, if the UE observes that its TA value is no longer valid, it falls back to RACH-based RA.

[0085] Hereinafter, an example signaling process200B for uplink grant control in conditional C-LTM according to some embodiments of the present disclosure will be described with referent to Fig. 2B. For the purpose of discussion, the communication process 200A will be described with reference to Fig. 1 . It would be appreciated that although the communication process 200B has been described referring to the network environment 100 of Fig. 1, this communication process 200B may be likewise applied to other similar communication scenarios. It should be appreciated that the terminal device 201 is an example of the terminal device 110 of Fig. 1 and the first network device 202 is an example of the network device 130 (i.e. a target DU) of Fig. 1 .

[0086] As shown in Fig. 2B, the terminal device 201 determines (220), after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met. In some embodiments, the terminal device determines whether the condition fortriggering the C-LTM for the candidate cell of the first network device is met by determining whether a measurement result is above a measurement threshold configured by the first network device and comprised in a C-LTM configuration. Based on determining that the condition for triggering the C-LTM is met, the terminal device 201 transmits (225) a request for dynamic grant (DG) activation. The request for DG activation may be not directly transmitted to the first network device, as shown by the dotted line. The network device 202 receives (230) the request for DG activation.

[0087] In some embodiments, the request for DG activation is transmitted from the terminal device to a centralized unit which forwards the request for DG activation to the first network device. Alternatively, the request for DG activation is transmitted from the terminal device to a second network device serving the terminal device. In this event, the second network device forwards the request for DG activation to the centralized unit, and the centralized unit forwards the request for DG activation to the first network device. Alternatively, the request for DG activation is transmitted from the terminal device to the first network device.

[0088] For example, in some embodiments, UE sends DG activation request to CU. Alternatively, UE sends DG activation request to S-DU, and S-DU sends DG activation request to CU and CU sends DG activation request to T-DU, and then, the T-DU activates the DG, and the T-DU sends DG to CU. CU sends DG to S-DU which forwards it to the UE. For example, DG may be sent through PDCCH order or MAC CE. For example, UE can inform S-DU that it is getting ready to trigger a cell switch. S-DU informs CU that UE is getting ready to trigger a cell switch. CU informs T-DU to activate the DG. T-DU informs CU that it has activated the DG. CU informs S-DU that the DG is activated. S-DU may inform UE that DG is activated. In another case, CU does not inform UE that DG is activated, but UE sends CFRA preamble to T-DU. UE may monitor for DG from T-DU. Once UE observes that T-DU is scheduling DG, UE sends DG to T-DU.

[0089] Alternatively, UE sends DG activation request to T-DU, and T-DU activates DG and sends DG to UE.

[0090] Alternatively, UE sends DG activation request to T-DU, and T-DU activates DG, and sends DG to CU, and CU sends DG to S-DU, and S-DU sends DG of the T-DU to the UE, and UE receives the DG of the T-DU and sends it to T-DU. DG may be sent via DCI, e.g. PDCCH order, or MAC signalling, e.g. dedicated MAC CE. For example, UE sends CFRA preamble to T-DU. T-DU activates DG. T-DU informs CU which informs S-DU that DG is activated. S-DU can inform the UE that T-DU has activated DG.

[0091] In some embodiments, the terminal device determines whether or not the DG is activated by monitoring a DG activation indication, from the first network device, the second network device serving the terminal device, or the centralized unit, and a predefined number of slots or a predefined of time period that is configured by the first network device and comprised in a C-LTM configuration.

[0092] In some embodiments, the terminal device transmits a DG transmission to the first network device based on determining that the DG is activated; or retransmit a further request for DG activation for a predefined number of times that is configured by the first network device based on determining that the DG is not activated. For example, if UE observes that target DU has received the CFRA preamble (e.g., PDCCH indicating DG activation (not always needed to include uplink grant), UE sends DG. If UE observes that target DU has not received the CFRA preamble (e.g., target DU is not scheduling DG transmission), UE retries sending CFRA preamble.

[0093] In some embodiments, the DG activation indication is received by receiving a first physical downlink control channel (PDCCH) order from the first network device, after the early synchronization procedure, and the first PDCCH order comprising the DG of the first network device is monitored by the terminal device to obtain the DG. For example, UE is configured with DG or CG type 2 for conditional LTM. UE is also configured with CFRA or Scheduling Request or uplink signal to be sent on C-LTM cell-switch. Network does not answer with a RAR to the CFRA preamble as the network is configured to activate DG procedure or CG type 2. The network may transmit DG or the CS-RNTI (to activate CG type 2) in a periodic manner after the early TA acquisition or early DL sync at the source side. UE sends the uplink signal and waits for PDCCH, and PDCCH provides dynamic grant for sending first uplink message or it provides CS-RNTI to activate the uplink grant.

[0094] In some embodiments, the DG activation indication is received by receiving, from the second network device serving the terminal device, a second PDCCH order comprising the DG of the first terminal device or a dedicated medium access control-control element (MAC CE) comprising the DG from the first terminal device, after the early synchronization procedure, the DG is transmitted to the second network device from the first network device.

[0095] In some embodiments, the first or second PDCCH order or the MAC CE further comprises timing advance (TA) value information, a transmission configuration indication (TCI) state to be activated or deactivated by the terminal device, or both of them.

[0096] For example, UE is configured with DG for conditional LTM. UE is also configured with CFRA or Scheduling Request or uplink signal to be sent on C-LTM cell-switch. UE sends the uplink signal to target DU and wait for PDCCH. Target DU sends the UL grant to the source DU (through the S-CU). Target DU can also send information about TA and TCI states to be activated / deactivated in the UE. S-DU sends the PDCCH order containing the UL grant to the UE. PDCCH provides dynamic grant for sending first uplink message to target DU. PDCCH order can also contain information on the TA value and the TCI states to be activated / deactivated by the UE.

[0097] In some embodiments, the DG activation indication comprises information on a periodicity of the DG scheduling, a slot for the terminal device to send UL grant data, or both of them.

[0098] In some embodiments, the terminal device receives, from a second network device serving the terminal device, a message indicating the terminal device to retransmit the request for DG activation via a third PDCCH order, a second MAC-CE, a TCI state activation command, a TA value, or any combination thereof.

[0099] In some embodiments, the terminal device transmits, to a second network device serving the terminal device, or to a centralized unit via the second network device, an indication that the terminal device has attempted to transmit the request for DG activation to the first network device. In some embodiments, the indication that the terminal device has attempted to transmit the request for DG activation to the first network device comprises a specific cell to which the terminal device has transmitted the request for DG activation. Alternatively or additionally, the indication comprises a first TCI state that has been activated. Alternatively or additionally, the indication comprises a second TCI state that is relevant for the specific cell to which the terminal device has transmitted the request for DG activation. Alternatively or additionally, the indication comprises multiple activated or deactivatedTCI states including indications for multiple cells for which terminal device has transmitted the request for DG activation. Alternatively or additionally, the indication comprises an indication in a measurement report from the terminal device to the second network device serving the terminal device.

[0100] In some embodiments, the request of DG activation comprises a preamble used for TA acquisition or a dedicated preamble indicated to the terminal device for uplink grant activation. In some embodiments, the dedicated preamble indicated to the terminal device for uplink grant activation comprises a preamble provided to the terminal device for random access channel (RACH)-based access to the first network device.

[0101] In some embodiments, the terminal device transmits the request for DG activation on a RACH occasion associated with a selected synchronization signal block (SSB) which is selected based on an early downlink (DL) or uplink (UL) procedure or based on a latest DL measurement, and the selected SSB is associated with an activated or indicated transmission configuration indication (TCI) state, an early timing advance (TA) acquisition procedure, a terminal device-based TA estimation, or a physical downlink control channel (PDCCH)-ordered RACH procedure.

[0102] In some embodiments, the terminal device falls back to RACH-based random access based on determining that a DG transmission is unsuccessful, a predefined number of times for retransmitting the request for DG activation of is exhausted, a timing advance value is no longer valid, or any combination of them.

[0103] In some embodiments, the DG activation indication comprises a dynamic uplink grant for the terminal device to transmit a first uplink message to the first network device. Alternatively or additionally, the DG activation indication comprises a configured scheduling radio network temporary identifier (CS-RNTI) for activating configurated grant (CG) type 2, in the case that the DG comprises the CG type 2.

[0104] Fig. 3 illustrates an example signaling process 300 during the preparation phase according to some embodiments of the present disclosure.

[0105] As shown in Fig. 3, at step 8, the CU 340 configures initial and subsequent conditional cell switch execution conditions. Further, the CU 340 configures thresholds based on which UE should attempt CFRA preamble transmission for CG activation. In one embodiment, if UE is configured with L1 measurements, these thresholds are based on L1 measurements. In another embodiment, if UE is not configured with L1 measurements but is configured with L3 measurements, these thresholds are based on L3 measurements. Depending on the indicated UE capabilities, UE can also be configured with a mixture of the two thresholds, i.e., L1 measurement threshold for some LTM candidates and L3 measurement thresholds for others.

[0106] In case both L1 and L3 conditions trigger for different cells, NW gives a priority order for C-LTM switching (e.g., UE priorities triggering C-LTM for cells for which the trigger based on L3 measurement is activated). In another implementation, it is left for UE to choose whether it should prioritize executing C-LTM based on the activated L1 or L3 measurement-based triggers. In yet another implementation, it may be defined in the specification whether L1 or L3 measurement-based trigger shall be prioritized.

[0107] Furthermore, the CU 340 configures the number of times the UE 310 should attempt to send the contention free random access (CFRA) preamble to request the target 330 to activate the configured grant (CG) or dynamic grant (DG). In another embodiment, UE can also give a power ramping counter for the UE to send theCFRA preambles, i.e., with each TX of the CFRA preamble, the UE increases its transmission power.

[0108] Furthermore, the CU 340 configures the number of slots the UE 310 should wait before trying to retransmit the CFRA preamble. In another embodiment, this can be a timer that CU 340 configures towards the UE 310. The timer starts when UE finishes sending the CFRA preamble. Upon the timer expiry, UE sends another CFRA preamble to the NW.

[0109] That is to say, the UE 310 will use the CG or DG to NW only when it is informed by the NW. NW configures the following for the UE, for example, conditions on when to inform the NW that UE is planning to trigger cell switch after an early synchronization procedure (e.g., UE sends CFRA preamble to inform the NW that it is preparing to trigger cell switch when a pre-defined threshold is met). In one embodiment, the UE sends the CFRA preamble when the conditional cell change condition is met. In another embodiment, the UE sends the preamble when a condition that is offset to the conditional cell execution condition by X dB is met, so that it may receive confirmation from the NW early on and be ready to use the CG or DG upon execution of the cell switch.

[0110] Fig. 4A to Fig. 4C illustrate another example signaling process 400A, 400B, and 400C during the C-LTM execution phase according to some embodiments of the present disclosure, and the steps may be different from those described with reference to Figs. 4 and 6.

[0111] As shown in Fig. 4A to Fig. 4B, the target DU may perform the activation of the CG when receiving a request for CG activation (for example, a CFRA preamble or a scheduling request) directly or indirectly from the UE, and the request for the CG activation is sent by the UE when the condition for triggering C-LTM is met. As shown in Fig.4C, the target DU may perform the activation of the DG when receiving a request for DG activation (for example, a CFRA preamble or a scheduling request) directly or indirectly from the UE, and the request for the DG activation is sent by the UE when the condition for triggering C-LTM is met.

[0112] As described earlier, UE monitors if L1 / L3 measurement-based triggers for sending CFRA preamble are met. When L1 / L3 measurement-based triggers for sending CFRA preamble are met, UE sends CFRA preamble to the selected target DU. If CFRA preamble transmission is not acknowledged, the UE does not send CFRA preamble. A case, where this preamble is not received by the NW, would be if the uplink channel is weak (e.g., UE is in deep fade). In such cases, the UL CFRA preamble transmission from UE to NW will not go through. If the UL channel between UE and NW is good, then NW will receive the CFRA transmission and will activate the CG.

[0113] As shown in Fig. 4A, for option 1 , alternative 1 , the UE 410 sends CFRA preamble at step 1 and waits for a predefined number of slots at step 2, or a certain amount of time and then attempts CG transmission at step 3, that is to say, the NW can configure UE to blindly send CG. If CG transmissions is not successful (e.g., UE exhausts maximal allowed number of CG transmissions, timer associated with sending CG expires), the UE 410 falls back to RACH-based RA. Similarly, if the UE 410 observes that its TA value is no longer valid, UE falls back to RACH-based RA.

[0114] As shown in Fig. 4A, for option 1 , alternative 2, the UE 410 sends CFRA preamble at step 5 and waits for a predefined number of slots, or a certain amount of time. Then, the UE monitors if CG is activated (i.e., an indication from the target DU, for example, message 4 is received at step 6) at step 6. The indication can be received via for example, a PDCCH order, or a MAC CE, and the like. If CG is activated, the UE 310 sends CGto target cell at step 7. If UE monitors the permission for sending CG at step 6, it is more accurate (since UE knows when / whether to send CG). If CG is not activated, in a certain amount of time / slots UE retries sending CFRA preamble.

[0115] If the number of times UE can send CFRA preamble is exhausted, the UE 410 falls back to RACH-based RA. Similarly, if the UE observes that its TA value is no longer valid, it falls back to RACH-based RA.

[0116] For the option 1 , the UE is configured with CG Grant for C-LTM and CFRA preamble(s) for CG activation. In one embodiment, the CFRA preambles for CG activation can be the same as the dedicated ones provided to the UE for RACH-based access to the target. The target has the following options: the target provides RAR anyway (will be lost as the UE will use the CG); and based on having configured CG and the UE either being configured with UE-based TA or having a valid (e.g. not expired) RACH-based TA, the targets does not provide RAR.

[0117] UE first sends contention free random access (CFRA) preamble or scheduling request to target DU and waits for pre-defined number of slots. Then, if UE observes that target DU has received the CFRA preamble (e.g., PDCCH indicating CG activation (not always needed to include uplink grant), UE will send CG. If UE observes that target DU has not received the CFRA preamble (e.g., target DU is not scheduling CG transmission), UE retries sending CFRA preamble. The UE sends the CFRA preamble on a RACH occasion associated with a selected SSB, which may be chosen based on the early DL / UL procedure (e.g., the SSB associated with the activated / indicated TCI state, the SSB for which an early TA acquisition procedure, UE-based TA estimation, or a PDCCH-ordered RACH procedure was performed) or based on the latest DL measurement.

[0118] As shown in Fig. 4B, at step 9 for option 2, alternative 1 , the UE 410 sends CFRA preamble and waits to receive permission to use CG from source DU. In one embodiment, this can be the same CFRA preamble used for early TA acquisition. In another embodiment, this can be a dedicated preamble given to the UE for UL grant activation, for example, the dedicated preamble provided to the UE for RACH-based access to the target.

[0119] For option 2, alternative 1 , if target DU 440 receives the CFRA preamble sent by the UE, it activates the CG and informs S-DU that it is waiting for CG transmission from UE. In one embodiment, target DU periodically schedules CG at step 10. Information on the periodicity of the CG scheduling is informed to the source DU at step 11. Moreover, in another implementation, target DU can inform the source DU about the exact slot in which the UE should send the UL grant. Then, S-DU 420 informs UE to send CG to T-DU at step 12. This can be through a PDCCH order, dedicated MAC CE, or implicitly, by sending a TCI state activation command or a TA value. In another implementation, the S-DU 420 can send TCI state deactivation command, instructing the UE to deactivate all TCI states but the one it should use for sending the CG. In yet another implementation, S-DU 420 can indicate to the UE to perform early decoding of the configuration of the candidate cell pertaining to the target DU. This implicitly also indicates to the UE that target DU is waiting for the UE to send the UL grant.

[0120] The UE 410 can also send indication to S-DU 420 informing it has attempted to send CFRA preamble to T-DU. In another implementation, UE implicitly informs S-DU about the cells for which it has sent CFRA preamble. As an example, UE can inform S-CU about the TCI state it has activated. In one implementation, UE only informs S-CU about the TCI states that are relevant for the target cell to which the UE has sent CFRA preamble. In another implementation, UE informs S-CU about all the activated / deactivated TCI states and includes an indicationfor the cells for which it has requested CG activation.

[0121] In another implementation, S-DU 420 can either inform target 440, or request UE to send CFRA preamble again to T-DU. This can be at least through a PDCCH order, dedicated MAC CE, or implicitly, by sending a TCI state activation command, a TA value or a combination of the aforementioned alternatives. UE repeats this procedure until a maximum number of TX is allowed. Otherwise, UE falls back to RACH-based RA. Similarly, if the UE observes that its TA value is no longer valid, it falls back to RACH-based RA.

[0122] As shown in Fig. 4B, for option 2, alternative 2, the UE 410 is configured with both CLTM and also with L3 measurements for another purpose than CLTM (for example non-conditional LTM or L3 mobility) for a certain candidate cell. It observes that condition to send CFRA preamble to target DU is met. The UE 410 sends CFRA preamble at step 15, and sends the L3 measurement report at step 16 and step 17, and waits to receive permission to use CG from source DU. In one embodiment, this can be the same CFRA preamble used for early TA acquisition. In another embodiment, this can be a dedicated preamble given to the UE for UL grant activation.

[0123] The UE can also send indication to S-CU informing it has attempted to send CFRA preamble to T-DU. For example, this can be a flag in the measurement report sent from the UE to the source DU. In case Conditional LTM is configured with L3 measurements, then this flag is included in the L3 measurement report which goes to CU. In other embodiments, the UE implicitly informs S-DU about the cells for which it has sent CFRA preamble. As an example, UE can inform S-CU about the TCI state it has activated. In one implementation, UE only informs S-CU about the TCI states that are relevant for the target cell to which the UE has sent CFRA preamble. In another implementation, UE informs S-CU about all the activated / deactivated TCI states and includes an indication for the cells for which it has requested CG activation.

[0124] The CU 430 then informs the target DU 440 about activating the CG at step 18. Upon activation of the CG, target DU informs CU ate step 19, which then forwards the information to the UE at step 20. In one implementation, this is done with the S-DU awareness and signalling. In another implementation, CU directly informs the UE through RRC signalling.

[0125] UE repeats this procedure until a maximum number of TX is allowed. Otherwise, UE falls back to RACH-based RA. Similarly, if the UE observes that its TA value is no longer valid, it falls back to RACH-based RA.

[0126] For example, for this option 2, UE sends CFRA preamble and waits to receive permission to send CG from source DU. If target DU received the CFRA preamble sent by the UE, it activates the CG and informs S-DU that it is waiting for CG transmission from UE. S-DU then informs UE to send CG to T-DU. UE can also send indication to S-DU informing it has attempted to send CFRA preamble to T-DU. S-DU can either inform target, or request UE to send CFRA preamble again to T-DU. UE repeats this procedure until a maximum number of TX is allowed. Otherwise, UE falls back to RACH.

[0127] As shown in Fig. 4C, for option 3, alternative 1 , UE is configured with dynamic grant (DG) or configured grant (GC) type 2 for conditional LTM. The UE is also configured with CFRA or Scheduling Request or uplink signal to be sent on C-LTM cell-switch. Network does not answer with a RAR to the CFRA preamble as the network is configured to activate DG procedure or CG type 2. The network may transmit DG or the configuredscheduling radio network temporary identifier (CS-RNTI) (to activate CG type 2) in a periodic manner after the early TA acquisition or early DL sync at the source side.

[0128] UE sends the uplink signal at step 23 and waits for PDCCH at step 24. The target DU 440 schedules periodic DG transmission at step 25, and provides PDCCH order at step 26. PDCCH provided at step 26, provides dynamic grant for sending first uplink message or it provides CS-RNTI to activate the uplink grant. Then, the UE provides DG transmission at step 27.

[0129] As shown in Fig. 4C, for option 3, alternative 2, the source CU 430 will send the DG of the target DU 440, and it is related to dynamic grant triggering based on CFRA or SR. UE is configured with DG for conditional LTM. UE is also configured with CFRA or Scheduling Request or uplink signal to be sent on C-LTM cell-switch.

[0130] UE sends the uplink signal at step 28 to target DU and wait for PDCCH at step 29. The target DU 440 schedules the periodic DG transmission at step 30, and sends the information needed for the DG, TA and TCI states to the activated to the source CU 440. Target DU sends the UL grant to the source DU (through the S- CU) at steps 31 and 32. Target DU can also send information about TA and TCI states to be activated / deactivated in the UE at steps 31 and 32. S-DU sends the PDCCH order containing the UL grant to the UE at step 33. PDCCH provides dynamic grant for sending first uplink message to target DU. PDCCH order can also contain information on the TA value and the TCI states to be activated / deactivated by the UE. Then, the UE provides DG transmission at step 34.

[0131] For option 3, UE also repeats this procedure until a maximum number of TX is allowed. Otherwise, UE falls back to RACH-based RA. Similarly, if the UE determines that its TA value is no longer valid, it falls back to RACH-based RA. If TA validity timer in the UE has expired, the TA value is no longer valid.

[0132] Although some signaling are only described for option 1 , option 2, and option 3, it should be appreciated that some related signaling may be also applicable for other options. Although as shown in Figs. 8A to 8C, the CFRA preamble is provided to the target DU from the terminal device, it should be appreciated that CFRA preamble can be provided to the source CU then it forwards the preamble to the target DU. Alternatively, the CFRA preamble can be provided to the source DU from the terminal device, then the source DU forwards it to the source CU, and the source CU forwards it to the target DU.

[0133] Thus, for the option 3, Dynamic Grant triggering is based on CFRA or SR. UE is configured with DG for conditional LTM. UE is also configured with CFRA or Scheduling Request or uplink signal to be sent on C-LTM cell-switch. In one embodiment, the CFRA can be the same CFRA preamble used for early TA acquisition. In another embodiment, this can be a dedicated preamble given to the UE for UL grant activation, for example, the dedicated preamble provided to the UE for RACH-based access to the target. Network does not answer with a RAR to the CFRA preamble as the network is configured to activate DG procedure. Alternatively, the network may transmit DG in a periodic manner after the early TA acquisition or early DL sync at the source side. UE sends the uplink signal and wait for PDCCH. PDCCH provides dynamic grant for sending first uplink message.

[0134] As for the Early synchronization, especially, for RACH-based early TA acquisition, for RACH-less access to the target cell, apart from the TA, the UE must be provided with an UL grant. In Rel. 18 LTM, both CG and DG were supported as they have their own benefits. Providing a CG may incur a large resource reservation overhead,especially when multiple CGs for multiple UEs are provided by the target cell, with the resources being reserved from RRC configuration to cell switch execution. Nevertheless, for non-conditional LTM, thanks to the network triggering of the cell switch and the transmission of cell switch notification, optimizations of the resource management on the network side are possible, as well as monitoring of the CG only after a cell switch has been decided. The lack of network control on cell switch in CLTM calls for alternative solutions to avoid monitoring of the CGs starting from RRC configuration and to enable more flexible resource management on the network side. To this end, as the RAR transmission may constitute the last signaling exchange between the UE and the source cell before a potential conditional cell switch, the RAR transmission and its preceding steps (RA preamble transmission, TA information transfer) may be used for the activation of a configured grant (CG). On the other hand, utilizing a DG mitigates issues related to increased resource reservation which were discussed earlier for CG. Moreover, this makes it easier for the NW and UE to be in sync with respect to UL grant activation and monitoring.

[0135] In view of the foregoing, some embodiments of the present application propose solution for the proposal of "CG and DG are supported, and RAN2 to discuss CG and DG activation based on RACH-based early TA acquisition procedure”.

[0136] Further, as discussed, allowing the UE to trigger a cell switch execution has significant impact on the actions that need to be taken before and after a conditional cell switch. An important consequence is the network's uncertainty about the timing of the cell switch, which makes the preparation of the network for the UE's access to the target cell more complicated. A possible way to overcome this challenge and simplify the procedures related to UE's first access to the target is the transmission of a message from the UE to the source cell, informing the source cell that a conditional cell switch condition has been met. Upon receiving such a notification, the source cell can trigger procedures for UE's access to the target cell as in Rel. 18 LTM, e.g., send a cell switch notification, or it can even decide whether a cell switch is allowed, in case more network control on the cell switch is desired, and inform the UE about it.

[0137] Nevertheless, such a message may never reach the source cell as the UE-source cell link quality may already be too low soon after the conditional cell switch condition is met. In addition, while the UE will be waiting for a response to the message, the link may further deteriorate potentially resulting in radio link failure. Therefore, we should further study if and whether this message should be transmitted and how long the UE should wait for a response.

[0138] In view of the foregoing, some embodiments of the present application propose a solution for the proposal of "study whether and under which conditions the UE should send a message to the network informing about the triggering of a conditional cell switch condition”.

[0139] Fig. 5A shows a flowchart of an example method 500A implemented at a terminal device (for example, the terminal device 110) in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 500A will be described from the perspective of the terminal device 110 with reference to Fig. 1.

[0140] At block 510, the terminal device determines, after an early synchronization procedure, whether acondition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met. At block 520, the terminal device based on determining that the condition for triggering the C-LTM is met, transmits a request for configurated grant (CG) activation.

[0141] In some embodiments, the request for CG activation is transmitted from the terminal device to a centralized unit which forwards the request for CG activation to the first network device; the request for CG activation is transmitted from the terminal device to a second network device serving the terminal device, wherein the second network device forwards the request for CG activation to the centralized unit, and the centralized unit forwards the request for CG activation to the first network device; or the request for CG activation is transmitted from the terminal device to the first network device.

[0142] In some embodiments, the terminal device waits for a predefined number of slots or a predefined time period after transmitting the request for CG activation; and transmits for an allowed number of times, to the first network device, a CG transmission for an allowed number of times, after the predefined number of slots or the predefined of time period, without permission from the first network device to send the CG transmission.

[0143] In some embodiments, the terminal device determines whether or not the CG is activated by monitoring a CG activation indication, from the first network device, the second network device serving the terminal device, or the centralized unit, within a predefined number of slots or a predefined of time period that is configured by the first network device and comprised in a C-LTM configuration.

[0144] In some embodiments, the terminal device transmits a CG transmission to the first network device, based on determining that the CG is activated; or retransmits a further request for CG activation for a predefined number of times that is configured by the first network device, based on determining that the CG is not activated.

[0145] In some embodiments, the CG activation indication is received, from the first network device, by receiving an indication from the first network device for indicating that the CG is activated. In some embodiments, the CG activation indication is received from the second network device serving the terminal device, wherein the CG activation indication is transmitted to the second network device from the first network device via the centralized unit.

[0146] In some embodiments, the CG activation indication is received by at least one of the following: a first PDCCH order; a first dedicated media access control-control element (MAC-CE); a first TCI state activation command; a first TA value; or indicating the terminal device to perform early decoding of configuration of the candidate cell pertaining to the first network device.

[0147] In some embodiments, the CG activation indication is received from the centralized unit (CU), wherein the CG activation indication is transmitted to the CU from the first network device. In some embodiments, the CG activation indication is received from the CU via a RRC signaling.

[0148] In some embodiments, the CG activation indication comprises at least one of the following: information on a periodicity of the CG scheduling; or a slot for the terminal device to send UL grant data.

[0149] In some embodiments, the terminal device receives, from a second network device serving the terminal device, a message indicating the terminal device to retransmit the request for CG activation via at least one of thefollowing: a second PDCCH order; a second MAC-CE; a second TCI state activation command; or a second TA value.

[0150] In some embodiments, the terminal device transmits, to a second network device serving the terminal device, or to a centralized unit via the second network device, an indication that the terminal device has attempted to transmit the request for CG activation to the first network device.

[0151] In some embodiments, the indication that the terminal device has attempted to transmit the request for CG activation to the first network device comprises at least one of the following: a specific cell to which the terminal device has transmitted the request for CG activation; a first TCI state that has been activated; a second TCI state that is relevant for the specific cell to which the terminal device has transmitted the request for CG activation; multiple activated or deactivated TCI states including indications for multiple cells for which terminal device has transmitted the request for CG activation; or an indicator in a measurement report from the terminal device to the second network device serving the terminal device.

[0152] In some embodiments, the first TCI state activation command is used to indicate the terminal device to deactivate one or more TCI states excluding the TCI state used by the terminal device to transmit the CG transmission. In some embodiments, the request of CG activation comprises a preamble used for TA acquisition or a dedicated preamble indicated to the terminal device for uplink grant activation.

[0153] In some embodiments, the dedicated preamble indicated to the terminal device for uplink grant activation comprises a preamble provided to the terminal device for random access channel (RACH)-based access to the first network device.

[0154] In some embodiments, the terminal device transmits the request for CG activation on a RACH occasion associated with a selected synchronization signal block (SSB) which is selected based on an early downlink (DL) or uplink (UL) procedure or based on a latest DL measurement, and the selected SSB is associated with an activated or indicated transmission configuration indication (TCI) state, an early timing advance (TA) acquisition procedure, a terminal device-based TA estimation, or a physical downlink control channel (PDCCH)-ordered RACH procedure.

[0155] In some embodiments, the terminal device falls back to RACH-based random access based on determining at least one of the following: a CG transmission is unsuccessful; a predefined number of times for retransmitting the request for CG activation is exhausted; or a timing advance value is no longer valid.

[0156] In some embodiments, the request for CG activation comprises at least one of the following: a contention free random access (CFRA) preamble; or a scheduling request.

[0157] In some embodiments, the terminal device determines whether the condition for triggering the C-LTM for the candidate cell of the first network device is met by: determining whether a measurement result is above a measurement threshold configured by the first network device and comprised in a C-LTM configuration.

[0158] Fig. 5B shows a flowchart of an example method 500B implemented at a terminal device (for example, the terminal device 110) in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 500B will be described from the perspective of the terminal device 110 with reference toFig. 1.

[0159] At block 510, the terminal device determines, after an early synchronization procedure, whether a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met. At block 520, the terminal device based on determining that the condition for triggering the C-LTM is met, transmits, a request for dynamic grant (DG) activation.

[0160] In some embodiments, the request for DG activation is transmitted from the terminal device to a centralized unit which forwards the request for DG activation to the first network device; the request for DG activation is transmitted from the terminal device to a second network device serving the terminal device, wherein the second network device forwards the request for DG activation to the centralized unit, and the centralized unit forwards the request for DG activation to the first network device; or the request for DG activation is transmitted from the terminal device to the first network device.

[0161] In some embodiments, the terminal device determines whether or not the DG is activated by monitoring a DG activation indication, from the first network device, the second network device serving the terminal device, or the centralized unit, within a predefined number of slots or a predefined of time period that is configured by the first network device and comprised in a C-LTM configuration.

[0162] In some embodiments, the terminal device transmits a DG transmission to the first network device based on determining that the DG is activated; or retransmits a further request for DG activation for a predefined number of times that is configured by the first network device based on determining that the DG is not activated.

[0163] In some embodiments, the DG activation indication is received by receiving a first physical downlink control channel (PDCCH) order from the first network device, after the early synchronization procedure, wherein the first PDCCH order comprising the DG of the first network device is monitored by the terminal device to obtain the DG.

[0164] In some embodiments, the DG activation indication is received by receiving, from the second network device serving the terminal device, a second PDCCH order comprising the DG of the first terminal device or a dedicated medium access control-control element (MAC CE) comprising the DG from the first terminal device, after the early synchronization procedure, wherein the DG is transmitted to the second network device from the first network device.

[0165] In some embodiments, the first or second PDCCH order or the MAC CE further comprises at least one of the following: timing advance (TA) value information; or a transmission configuration indication (TCI) state to be activated or deactivated by the terminal device.

[0166] In some embodiments, the DG activation indication comprises at least one of the following: information on a periodicity of the DG scheduling; or a slot for the terminal device to send UL grant data.

[0167] In some embodiments, the terminal device receives, from a second network device serving the terminal device, a message indicating the terminal device to retransmit the request for DG activation via at least one of the following: a third PDCCH order; a second MAC-CE; a TCI state activation command; or a TA value.

[0168] In some embodiments, the terminal device transmits, to a second network device serving the terminaldevice, or to a centralized unit via the second network device, an indication that the terminal device has attempted to transmit the request for DG activation to the first network device.

[0169] In some embodiments, the indication that the terminal device has attempted to transmit the request for DG activation to the first network device comprises at least one of the following: a specific cell to which the terminal device has transmitted the request for DG activation; a first TCI state that has been activated; a second TCI state that is relevant for the specific cell to which the terminal device has transmitted the request for DG activation; multiple activated or deactivated TCI states including indications for multiple cells for which terminal device has transmitted the request for DG activation; or an indication in a measurement report from the terminal device to the second network device serving the terminal device.

[0170] In some embodiments, the request of DG activation comprises a preamble used for TA acquisition or a dedicated preamble indicated to the terminal device for uplink grant activation. In some embodiments, the dedicated preamble indicated to the terminal device for uplink grant activation comprises a preamble provided to the terminal device for random access channel (RACH)-based access to the first network device.

[0171] In some embodiments, the terminal device transmits the request for DG activation on a RACH occasion associated with a selected synchronization signal block (SSB) which is selected based on an early downlink (DL) or uplink (UL) procedure or based on a latest DL measurement, wherein the selected SSB is associated with an activated or indicated transmission configuration indication (TCI) state, an early timing advance (TA) acquisition procedure, a terminal device-based TA estimation, or a physical downlink control channel (PDCCH)-ordered RACH procedure.

[0172] In some embodiments, the terminal device falls back to RACH-based random access based on determining at least one of the following: a DG transmission is unsuccessful; a predefined number of times for retransmitting the request for DG activation of is exhausted; or a timing advance value is no longer valid.

[0173] In some embodiments, the request for DG activation comprises at least one of the following: a contention free random access (CFRA) preamble; or a scheduling request.

[0174] In some embodiments, the terminal device determines whether the condition for triggering the C-LTM for the candidate cell of the first network device is met by: determining whether a measurement result is above a measurement threshold configured by the first network device and comprised in a C-LTM configuration.

[0175] In some embodiments, the DG activation indication comprises at least one of the following: a dynamic uplink grant for the terminal device to transmit a first uplink message to the first network device, or a configured scheduling radio network temporary identifier (CS-RNTI) for activating configurated grant (CG) type 2, in the case that the DG comprises the CG type 2.

[0176] Fig. 6A shows a flowchart of an example method 600A implemented at a network device (for example, the network device 130) in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 600A will be described from the perspective of network device 130 with reference to Fig. 1.

[0177] As shown in Fig. 6A, at block 610, the network device receives after an early synchronization procedure, a request for configurated grant (CG) activation in the case that a condition for triggering a conditional layer 1 orlayer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0178] In some embodiments, the request for CG activation is received from at least one of the following: the terminal device, or a centralized unit of the first network device, wherein the centralized unit receives the request for CG activation from a second network device serving the terminal device, and the second network device receives the request for CG activation from the terminal device, or the centralized unit receives the request for CG activation from the terminal device.

[0179] In some embodiments, the first network device receives, from the terminal device, a CG transmission for an allowed number of times, after a predefined number of slots or a predefined time period that is configured in a C-LTM configuration by a centralized unit and that passes before the terminal device performs the CG transmission after the transmission of the request for CG activation.

[0180] In some embodiments, the C-LTM configuration further comprises at least one of the following: a measurement threshold which is to be used by the terminal device to determine whether the condition for triggering the C-LTM is met; a number of slots between two adjacent requests for CG activation; or an allowed number of times that is to be used by the terminal device to transmit the request for CG activation. In some embodiments, the first network device activates the CG upon reception of the request for CG activation; and transmits a CG activation indication upon activation of the CG.

[0181] In some embodiments, the CG activation indication is transmitted, from the first network device to the terminal device or to a centralized unit (CU), by an indication that the CG is activated. In some embodiments, the CG activation indication is transmitted, from the first network device or from a second network device for serving the terminal device and for receiving the CG activation indication from the CU, to the terminal device, by at least one of the following: a first PDCCH order; a first dedicated media access control-control element (MAC-CE); a first TCI state activation command; a first TA value; or indicating the terminal device to perform early decoding of configuration of the candidate cell pertaining to the first network device.

[0182] In some embodiments, the CG activation indication is transmitted from the first network device via a CU of the first and second network devices by an RRC signaling. In some embodiments, the CG activation indication comprises at least one of the following: information on a periodicity of the CG scheduling; or a slot for the terminal device to sending a UL grant data.

[0183] In some embodiments, the first network device receives, from the terminal device, a CG transmission, in the case that the CG is activated; or receives a further request for CG activation for a predefined number of times that is configured by the first network device again, in the case that the CG is not activated.

[0184] In some embodiments, the request for CG activation comprises at least one of the following: a contention free random access (CFRA) preamble; or a scheduling request.

[0185] Fig. 6B shows a flowchart of an example method 600B implemented at a network device (for example, the network device 130) in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 600B will be described from the perspective of network device 130 with reference to Fig. 1 .

[0186] As shown in Fig. 6B, at block 610, the network device receives after an early synchronization procedure,a request for dynamic grant (DG) activation, in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0187] In some embodiments, the request for DG activation is received from a terminal device; the request for DG activation is received from a second network device serving the terminal device, wherein the second network device forwards the request for DG activation to a centralized unit, and the centralized unit forwards the request for DG activation to the first network device; or the request for DG activation is received from the centralized unit which forwards, to the first network device, the request for DG activation received from the terminal device.

[0188] In some embodiments, the first network device receives, from the terminal device, a DG transmission for an allowed number of times configured by a centralized unit in a C-LTM configuration.

[0189] In some embodiments, the C-LTM configuration further comprises at least one of the following: a measurement threshold which is to be used by the terminal device to determine whether the condition for trigger the C-LTM is met; a number of slots between two adjacent requests for DG activation; or an allowed number of times that is to be used by the terminal device to transmit the request for DG activation.

[0190] In some embodiments, the first network device activates the DG upon reception of the request for DG activation; and transmits a DG activation indication upon activation of the DG. In some embodiments, the DG activation indication is transmitted from the first network device by a first physical downlink control channel (PDCCH) order comprising the DG of the first network device.

[0191] In some embodiments, the DG activation indication is transmitted to the terminal device, after the early synchronization procedure, from the first network device via a second network device serving the terminal device by at least one of the following: a second PDCCH order comprising the DG of the first network device; a dedicated media access control-control element (MAC-CE) comprising the DG of the first network device.

[0192] In some embodiments, the DG activation indication comprises at least one of the following: information on a periodicity of the DG scheduling; or a slot for the terminal device to sending a UL grant data.

[0193] In some embodiments, the first network device receives, from the terminal device a DG transmission in the case that the DG is activated; or receives a further request for DG activation for a predefined number of times that is configured by the first network device again in the case that the DG is not activated.

[0194] In some embodiments, the request for DG activation comprises at least one of the following: a contention free random access (CFRA) preamble; or a scheduling request.

[0195] In some embodiments, an apparatus capable of performing any of operations of the method 500A (for example, the terminal device 110) may include means for performing the respective steps of the method 500A. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0196] In some embodiments, the apparatus comprises means for determining, after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and means for based on determining that the condition for triggering the C-LTM is met, transmitting a request for configurated grant (CG) activation.

[0197] In some embodiments, the request for CG activation is transmitted from the terminal device to a centralized unit which forwards the request for CG activation to the first network device; the request for CG activation is transmitted from the terminal device to a second network device serving the terminal device, wherein the second network device forwards the request for CG activation to the centralized unit, and the centralized unit forwards the request for CG activation to the first network device; or the request for CG activation is transmitted from the terminal device to the first network device.

[0198] In some embodiments, the apparatus further comprises means for waiting for a predefined number of slots or a predefined time period after transmitting the request for CG activation; and means for transmitting for an allowed number of times, to the first network device, a CG transmission for an allowed number of times, after the predefined number of slots or the predefined of time period, without permission from the first network device to send the CG transmission.

[0199] In some embodiments, the apparatus further comprises means for determining whether or not the CG is activated by monitoring a CG activation indication, from the first network device, the second network device serving the terminal device, or the centralized unit, within a predefined number of slots or a predefined of time period that is configured by the first network device and comprised in a C-LTM configuration.

[0200] In some embodiments, the apparatus further comprises means for transmitting a CG transmission to the first network device, based on determining that the CG is activated; or retransmits a further request for CG activation for a predefined number of times that is configured by the first network device, based on determining that the CG is not activated.

[0201] In some embodiments, the CG activation indication is received, from the first network device, by receiving an indication from the first network device for indicating that the CG is activated. In some embodiments, the CG activation indication is received from the second network device serving the terminal device, wherein the CG activation indication is transmitted to the second network device from the first network device via the centralized unit.

[0202] In some embodiments, the CG activation indication is received by at least one of the following: a first PDCCH order; a first dedicated media access control-control element (MAC-CE); a first TCI state activation command; a first TA value; or indicating the terminal device to perform early decoding of configuration of the candidate cell pertaining to the first network device.

[0203] In some embodiments, the CG activation indication is received from the centralized unit (CU), wherein the CG activation indication is transmitted to the CU from the first network device. In some embodiments, the CG activation indication is received from the CU via a RRC signaling.

[0204] In some embodiments, the CG activation indication comprises at least one of the following: information on a periodicity of the CG scheduling; or a slot for the terminal device to send UL grant data.

[0205] In some embodiments, the apparatus further comprises means for receiving, from a second network device serving the terminal device, a message indicating the terminal device to retransmit the request for CG activation via at least one of the following: a second PDCCH order; a second MAC-CE; a second TCI state activationcommand; or a second TA value.

[0206] In some embodiments, the apparatus further comprises means for transmitting, to a second network device serving the terminal device, or to a centralized unit via the second network device, an indication that the terminal device has attempted to transmit the request for CG activation to the first network device.

[0207] In some embodiments, the indication that the terminal device has attempted to transmit the request for CG activation to the first network device comprises at least one of the following: a specific cell to which the terminal device has transmitted the request for CG activation; a first TCI state that has been activated; a second TCI state that is relevant for the specific cell to which the terminal device has transmitted the request for CG activation; multiple activated or deactivated TCI states including indications for multiple cells for which terminal device has transmitted the request for CG activation; or an indicator in a measurement report from the terminal device to the second network device serving the terminal device.

[0208] In some embodiments, the first TCI state activation command is used to indicate the terminal device to deactivate one or more TCI states excluding the TCI state used by the terminal device to transmit the CG transmission. In some embodiments, the request of CG activation comprises a preamble used for TA acquisition or a dedicated preamble indicated to the terminal device for uplink grant activation.

[0209] In some embodiments, the dedicated preamble indicated to the terminal device for uplink grant activation comprises a preamble provided to the terminal device for random access channel (RACH)-based access to the first network device.

[0210] In some embodiments, the apparatus further comprises means for transmitting the request for CG activation on a RACH occasion associated with a selected synchronization signal block (SSB) which is selected based on an early downlink (DL) or uplink (UL) procedure or based on a latest DL measurement, and the selected SSB is associated with an activated or indicated transmission configuration indication (TCI) state, an early timing advance (TA) acquisition procedure, a terminal device-based TA estimation, or a physical downlink control channel (PDCCH)-ordered RACH procedure.

[0211] In some embodiments, the apparatus further comprises means for falling back to RACH-based random access based on determining at least one of the following: a CG transmission is unsuccessful; a predefined number of times for retransmitting the request for CG activation is exhausted; or a timing advance value is no longer valid.

[0212] In some embodiments, the request for CG activation comprises at least one of the following: a contention free random access (CFRA) preamble; or a scheduling request.

[0213] In some embodiments, the mean for determining determines whether the condition for triggering the C- LTM for the candidate cell of the first network device is met by: determining whether a measurement result is above a measurement threshold configured by the first network device and comprised in a C-LTM configuration.

[0214] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 500A. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0215] In some embodiments, an apparatus capable of performing any of operations of the method 500B (for example, the terminal device 110) may include means for performing the respective steps of the method 500B. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0216] In some embodiments, the apparatus comprises means for determining, after an early synchronization procedure, whether a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and means for based on determining that the condition for triggering the C-LTM is met, transmitting, a request for dynamic grant (DG) activation.

[0217] In some embodiments, the request for DG activation is transmitted from the terminal device to a centralized unit which forwards the request for DG activation to the first network device; the request for DG activation is transmitted from the terminal device to a second network device serving the terminal device, wherein the second network device forwards the request for DG activation to the centralized unit, and the centralized unit forwards the request for DG activation to the first network device; or the request for DG activation is transmitted from the terminal device to the first network device.

[0218] In some embodiments, the apparatus further comprises means for determining whether or not the DG is activated by monitoring a DG activation indication, from the first network device, the second network device serving, or the centralized unit, within a predefined number of slots or a predefined of time period that is configured by the first network device and comprised in a C-LTM configuration.

[0219] In some embodiments, the apparatus further comprises means for transmitting a DG transmission to the first network device based on determining that the DG is activated; or retransmits a further request for DG activation for a predefined number of times that is configured by the first network device based on determining that the DG is not activated.

[0220] In some embodiments, the DG activation indication is received by receiving a first physical downlink control channel (PDCCH) order from the first network device, after the early synchronization procedure, wherein the first PDCCH order comprising the DG of the first network device is monitored by the terminal device to obtain the DG.

[0221] In some embodiments, the DG activation indication is received by receiving, from the second network device serving the terminal device, a second PDCCH order comprising the DG of the first terminal device or a dedicated medium access control-control element (MAC CE) comprising the DG from the first terminal device, after the early synchronization procedure, wherein the DG is transmitted to the second network device from the first network device.

[0222] In some embodiments, the first or second PDCCH order or the MAC CE further comprises at least one of the following: timing advance (TA) value information; or a transmission configuration indication (TCI) state to be activated or deactivated by the terminal device.

[0223] In some embodiments, the DG activation indication comprises at least one of the following: information on a periodicity of the DG scheduling; or a slot for the terminal device to send UL grant data.

[0224] In some embodiments, the apparatus further comprises means for receiving, from a second network device serving the terminal device, a message indicating the terminal device to retransmit the request for DG activation via at least one of the following: a third PDCCH order; a second MAC-CE; a TCI state activation command; or a TA value.

[0225] In some embodiments, the apparatus further comprises means for transmitting, to a second network device serving the terminal device, or to a centralized unit via the second network device, an indication that the terminal device has attempted to transmit the request for DG activation to the first network device.

[0226] In some embodiments, the indication that the terminal device has attempted to transmit the request for DG activation to the first network device comprises at least one of the following: a specific cell to which the terminal device has transmitted the request for DG activation; a first TCI state that has been activated; a second TCI state that is relevant for the specific cell to which the terminal device has transmitted the request for DG activation; multiple activated or deactivated TCI states including indications for multiple cells for which terminal device has transmitted the request for DG activation; or an indication in a measurement report from the terminal device to the second network device serving the terminal device.

[0227] In some embodiments, the request of DG activation comprises a preamble used for TA acquisition or a dedicated preamble indicated to the terminal device for uplink grant activation. In some embodiments, the dedicated preamble indicated to the terminal device for uplink grant activation comprises a preamble provided to the terminal device for random access channel (RACH)-based access to the first network device.

[0228] In some embodiments, the apparatus further comprises means for transmitting the request for DG activation on a RACH occasion associated with a selected synchronization signal block (SSB) which is selected based on an early downlink (DL) or uplink (UL) procedure or based on a latest DL measurement, wherein the selected SSB is associated with an activated or indicated transmission configuration indication (TCI) state, an early timing advance (TA) acquisition procedure, a terminal device-based TA estimation, or a physical downlink control channel (PDCCH)-ordered RACH procedure.

[0229] In some embodiments, the apparatus further comprises means for falling back to RACH-based random access based on determining at least one of the following: a DG transmission is unsuccessful; a predefined number of times for retransmitting the request for DG activation of is exhausted; or a timing advance value is no longer valid.

[0230] In some embodiments, the request for DG activation comprises at least one of the following: a contention free random access (CFRA) preamble; or a scheduling request.

[0231] In some embodiments, the means for determining determines whether the condition for triggering the C- LTM for the candidate cell of the first network device is met by: determining whether a measurement result is above a measurement threshold configured by the first network device and comprised in a C-LTM configuration.

[0232] In some embodiments, the DG activation indication comprises at least one of the following: a dynamic uplink grant for the terminal device to transmit a first uplink message to the first network device, or a configured scheduling radio network temporary identifier (CS-RNTI) for activating configurated grant (CG) type 2, in the casethat the DG comprises the CG type 2.

[0233] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 500B. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0234] In some embodiments, an apparatus capable of performing any of operations of the method 600A (for example, the network device 130) may include means for performing the respective steps of the method 600A. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0235] In some embodiments, the apparatus comprises means for receiving after an early synchronization procedure, a request for configurated grant (CG) activation in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0236] In some embodiments, the request for CG activation is received from at least one of the following: the terminal device, or a centralized unit of the first network device, wherein the centralized unit receives the request for CG activation from a second network device serving the terminal device, and the second network device receives the request for CG activation from the terminal device, or the centralized unit receives the request for CG activation from the terminal device.

[0237] In some embodiments, the apparatus further comprises means for receiving, from the terminal device, a CG transmission for an allowed number of times, after a predefined number of slots or a predefined time period that is configured in a C-LTM configuration by a centralized unit and that passes before the terminal device performs the CG transmission after the transmission of the request for CG activation.

[0238] In some embodiments, the C-LTM configuration further comprises at least one of the following: a measurement threshold which is to be used by the terminal device to determine whether the condition for triggering the C-LTM is met; a number of slots between two adjacent requests for CG activation; or an allowed number of times that is to be used by the terminal device to transmit the request for CG activation. In some embodiments, the apparatus further comprises means for activating the CG upon reception of the request for CG activation; and transmitting a CG activation indication upon activation of the CG.

[0239] In some embodiments, the CG activation indication is transmitted, from the first network device to the terminal device or to a centralized unit (CU), by an indication that the CG is activated. In some embodiments, the CG activation indication is transmitted, from the first network device or from a second network device for serving the terminal device and for receiving the CG activation indication from the CU, to the terminal device, by at least one of the following: a first PDCCH order; a first dedicated media access control-control element (MAC-CE); a first TCI state activation command; a first TA value; or indicating the terminal device to perform early decoding of configuration of the candidate cell pertaining to the first network device.

[0240] In some embodiments, the CG activation indication is transmitted from the first network device via a CU of the first and second network devices by an RRC signaling. In some embodiments, the CG activation indication comprises at least one of the following: information on a periodicity of the CG scheduling; or a slot for the terminaldevice to sending a UL grant data.

[0241] In some embodiments, the apparatus further comprises means for receiving, from the terminal device, a CG transmission, in the case that the CG is activated; or receives a further request for CG activation for a predefined number of times that is configured by the first network device again, in the case that the CG is not activated.

[0242] In some embodiments, the request for CG activation comprises at least one of the following: a contention free random access (CFRA) preamble; or a scheduling request.

[0243] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 600A. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0244] In some embodiments, an apparatus capable of performing any of operations of the method 600B (for example, the network device 130) may include means for performing the respective steps of the method 600B. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

[0245] In some embodiments, the apparatus further comprises means for receiving after an early synchronization procedure, a request for dynamic grant (DG) activation, in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

[0246] In some embodiments, the request for DG activation is received from a terminal device; the request for DG activation is received from a second network device serving the terminal device, wherein the second network device forwards the request for DG activation to a centralized unit, and the centralized unit forwards the request for DG activation to the first network device; or the request for DG activation is received from the centralized unit which forwards, to the first network device, the request for DG activation received from the terminal device.

[0247] In some embodiments, the apparatus further comprises means for receiving, from the terminal device, a DG transmission for an allowed number of times configured by a centralized unit in a C-LTM configuration.

[0248] In some embodiments, the C-LTM configuration further comprises at least one of the following: a measurement threshold which is to be used by the terminal device to determine whether the condition for trigger the C-LTM is met; a number of slots between two adjacent requests for DG activation; or an allowed number of times that is to be used by the terminal device to transmit the request for DG activation.

[0249] In some embodiments, the apparatus further comprises means for activating the DG upon reception of the request for DG activation; and transmitting a DG activation indication upon activation of the DG. In some embodiments, the DG activation indication is transmitted from the first network device by a first physical downlink control channel (PDCCH) order comprising the DG of the first network device.

[0250] In some embodiments, the DG activation indication is transmitted to the terminal device, after the early synchronization procedure, from the first network device via a second network device serving the terminal device by at least one of the following: a second PDCCH order comprising the DG of the first network device; a dedicated media access control-control element (MAC-CE) comprising the DG of the first network device.

[0251] In some embodiments, the DG activation indication comprises at least one of the following: information on a periodicity of the DG scheduling; or a slot for the terminal device to sending a UL grant data.

[0252] In some embodiments, the apparatus further comprises means for receiving, from the terminal device a DG transmission in the case that the DG is activated; or receives a further request for DG activation for a predefined number of times that is configured by the first network device again in the case that the DG is not activated.

[0253] In some embodiments, the request for DG activation comprises at least one of the following: a contention free random access (CFRA) preamble; or a scheduling request.

[0254] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 600B. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

[0255] FIG. 7 is a simplified block diagram of a device 700 that is suitable for implementing embodiments of the present disclosure. The device 700 may be provided to implement the communication device, for example the terminal device 70, the first to third network device 120, 130, and 140 as shown in Fig. 1. As shown, the device 700 includes one or more processors 710, one or more memories 720 coupled to the processor 710, and one or more communication modules 740 coupled to the processor 710.

[0256] The communication module 740 is for bidirectional communications. The communication module 740 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

[0257] The processor 710 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 700 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

[0258] The memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a read only memory (ROM) 724, an electrically programmable read only memory (EPROM), a flash memory, a hard disk, a compact disc (CD), a digital video disk (DVD), and other magnetic storage and / or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 722 and other volatile memories that will not last in the power-down duration.

[0259] A computer program 730 includes computer executable instructions that are executed by the associated processor 710. The program 730 may be stored in the ROM 724. The processor 710 may perform any suitable actions and processing by loading the program 730 into the RAM 722.

[0260] The embodiments of the present disclosure may be implemented by means of the program so that the device 700 may perform any process of the disclosure as discussed with reference to Figs. 2 to Fig. 4C. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software andhardware.

[0261] In some embodiments, the program 730 may be tangibly contained in a computer readable medium which may be included in the device 700 (such as in the memory 720) or other storage devices that are accessible by the device 700. The device 700 may load the program 730 from the computer readable medium to the RAM 722 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 8 shows an example of the computer readable medium 800 in form of CD or DVD. The computer readable medium has the program 730 stored thereon.

[0262] Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0263] The present 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 program modules, being executed in a device on a target real or virtual processor, to carry out processes 200Ato 400C as described above with reference to Fig. 2Ato Fig. 4C. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0264] Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0265] In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

[0266] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of theforegoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term "non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0267] Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

[0268] Although the present disclosure has been described in languages specific to structural features and / or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

WE CLAIM:1 . A terminal device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: determine, after an early synchronization procedure, whether a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and based on determining that the condition for triggering the C-LTM is met, transmit, a request for dynamic grant (DG) activation.

2. The terminal device of claim 1, wherein: the request for DG activation is transmitted from the terminal device to a centralized unit which forwards the request for DG activation to the first network device; the request for DG activation is transmitted from the terminal device to a second network device serving the terminal device, wherein the second network device forwards the request for DG activation to the centralized unit, and the centralized unit forwards the request for DG activation to the first network device; or the request for DG activation is transmitted from the terminal device to the first network device.

3. The terminal device of claim 1 , wherein the terminal device is further caused to: determine whether or not the DG is activated by monitoring a DG activation indication, from the first network device, the second network device serving the terminal device, or the centralized unit, within a predefined number of slots or a predefined of time period that is configured by the first network device and comprised in a C-LTM configuration.

4. The terminal device of claim 2 or 3, wherein the terminal device is further caused to: transmit a DG transmission to the first network device based on determining that the DG is activated; or retransmit a further request for DG activation for a predefined number of times that is configured by the first network device based on determining that the DG is not activated.

5. The terminal device of any of claim 3 to 4, wherein the DG activation indication is received by receiving a first physical downlink control channel (PDCCH) order from the first network device, after the early synchronization procedure, wherein the first PDCCH order comprising the DG of the first network device is monitored by the terminal device to obtain the DG.

366. The terminal device of any of claim 3 to 5, wherein the DG activation indication is received by receiving, from the second network device serving the terminal device, a second PDCCH order comprising the DG of the first terminal device or a dedicated medium access control-control element (MAC CE) comprising the DG from the first terminal device, after the early synchronization procedure, wherein the DG is transmitted to the second network device from the first network device.

7. The terminal device of any of claims 5 to 6, wherein the first or second PDCCH order or the MAC CE further comprises at least one of the following: timing advance (TA) value information; or a transmission configuration indication (TCI) state to be activated or deactivated by the terminal device.

8. The terminal device of any of claims 4 to 7, wherein the DG activation indication comprises at least one of the following: information on a periodicity of the DG scheduling; or a slot for the terminal device to send UL grant data.

9. The terminal device of any of claim 4 to 8, wherein the terminal device is further caused to: receive, from a second network device serving the terminal device, a message indicating the terminal device to retransmit the request for DG activation via at least one of the following: a third PDCCH order; a second MAC-CE; a TCI state activation command; or a TA value.

10. The terminal device of any of claim 4 to 9, wherein the terminal device is further caused to: transmit, to a second network device serving the terminal device, or to a centralized unit via the second network device, an indication that the terminal device has attempted to transmit the request for DG activation to the first network device.

11. The terminal device of claim 10, wherein the indication that the terminal device has attempted to transmit the request for DG activation to the first network device comprises at least one of the following: a specific cell to which the terminal device has transmitted the request for DG activation; a first TCI state that has been activated; a second TCI state that is relevant for the specific cell to which the terminal device has transmitted the request for DG activation; multiple activated or deactivated TCI states including indications for multiple cells for which terminal device has transmitted the request for DG activation; or37an indication in a measurement report from the terminal device to the second network device serving the terminal device.

12. The terminal device of any of claims 1 to 11 , wherein the request of DG activation comprises a preamble used for TA acquisition or a dedicated preamble indicated to the terminal device for uplink grant activation.

13. The terminal device of claim 12, wherein the dedicated preamble indicated to the terminal device for uplink grant activation comprises a preamble provided to the terminal device for random access channel (RACI- - based access to the first network device.

14. The terminal device of any of claims 1 to 13, wherein the terminal device is caused to: transmit the request for DG activation on a RACH occasion associated with a selected synchronization signal block (SSB) which is selected based on an early downlink (DL) or uplink (UL) procedure or based on a latest DL measurement, wherein the selected SSB is associated with an activated or indicated transmission configuration indication (TCI) state, an early timing advance (TA) acquisition procedure, a terminal device-based TA estimation, or a physical downlink control channel (PDCCH)-ordered RACH procedure.

15. The terminal device of any of claims 1 to 14, wherein the terminal device is further caused to fall back to RACH-based random access based on determining at least one of the following: a DG transmission is unsuccessful; a predefined number of times for retransmitting the request for DG activation of is exhausted; or a timing advance value is no longer valid.

16. The terminal device of any of claims 1 to 15, wherein the request for DG activation comprises at least one of the following: a contention free random access (CFRA) preamble; or a scheduling request.

17. The terminal device of any of claims 1 to 16, wherein the terminal device is caused to determine whether the condition for triggering the C-LTM for the candidate cell of the first network device is met by: determining whether a measurement result is above a measurement threshold configured by the first network device and comprised in a C-LTM configuration.

18. The terminal device of claims 2 to 17, wherein the DG activation indication comprises at least one of the following: a dynamic uplink grant for the terminal device to transmit a first uplink message to the first network device,or a configured scheduling radio network temporary identifier (CS-RNTI) for activating configurated grant (CG) type 2, in the case that the DG comprises the CG type 2.

19. A first network device comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: receive, after an early synchronization procedure, a request for dynamic grant (DG) activation, in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

20. The first network device of claim 19, wherein the request for DG activation is received from a terminal device; the request for DG activation is received from a second network device serving the terminal device, wherein the second network device forwards the request for DG activation to a centralized unit, and the centralized unit forwards the request for DG activation to the first network device; or the request for DG activation is received from the centralized unit which forwards, to the first network device, the request for DG activation received from the terminal device.21 . The first network device of claim 19 or 20, wherein the first network device is further caused to: receive, from the terminal device, a DG transmission for an allowed number of times configured by a centralized unit in a C-LTM configuration.

22. The first network device of claim 19, wherein the C-LTM configuration further comprises at least one of the following: a measurement threshold which is to be used by the terminal device to determine whether the condition for trigger the C-LTM is met; a number of slots between two adjacent requests for DG activation; or an allowed number of times that is to be used by the terminal device to transmit the request for DG activation.

23. The first network device of any of claims 19 to 22, wherein the first network device is further caused to: activate the DG upon reception of the request for DG activation; and transmit a DG activation indication upon activation of the DG.

24. The first network device of claim 23, wherein the DG activation indication is transmitted from the first network device by a first physical downlink control channel (PDCCH) order comprising the DG of the first network device.

25. The first network device of claim 23, wherein the DG activation indication is transmitted to the terminal device, after the early synchronization procedure, from the first network device via a second network device serving the terminal device by at least one of the following: a second PDCCH order comprising the DG of the first network device; a dedicated media access control-control element (MAC-CE) comprising the DG of the first network device.

26. The first network device of any of claims 23 to 25, wherein the DG activation indication comprises at least one of the following: information on a periodicity of the DG scheduling; or a slot for the terminal device to sending a UL grant data.

27. The first network device of any of claims 23 to 26, wherein the first network device is further cased to: receive, from the terminal device a DG transmission in the case that the DG is activated; or receive a further request for DG activation for a predefined number of times that is configured by the first network device again in the case that the DG is not activated.

28. The first network device of any of claims 19 to 27, wherein the request for DG activation comprises at least one of the following: a contention free random access (CFRA) preamble; or a scheduling request.

29. A method at a terminal device comprising: determining, after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and based on determining that the condition for triggering the C-LTM is met, transmitting a request for dynamic grant (DG) activation.

30. A method at a first network device comprising: receiving, after an early synchronization procedure, a request for dynamic grant (DG) activation, in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

31. An apparatus comprising: means for determining, after an early synchronization procedure, whether a condition for triggering conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of a first network device is met; and means for based on determining that the condition for triggering the C-LTM is met, transmitting a request for dynamic grant (DG) activation.

32. An apparatus comprising: means for receiving, after an early synchronization procedure, a request for dynamic grant (DG) activation, in the case that a condition for triggering a conditional layer 1 or layer 2 triggered mobility (C-LTM) for a candidate cell of the first network device is met.

33. A computer readable medium comprising program instructions for causing an apparatus to perform at least the method of claim 29 or 30.41

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