[go: up one dir, main page]

WO2024093109A1 - Dispositifs et procédés de transfert sans rach - Google Patents

Dispositifs et procédés de transfert sans rach Download PDF

Info

Publication number
WO2024093109A1
WO2024093109A1 PCT/CN2023/084505 CN2023084505W WO2024093109A1 WO 2024093109 A1 WO2024093109 A1 WO 2024093109A1 CN 2023084505 W CN2023084505 W CN 2023084505W WO 2024093109 A1 WO2024093109 A1 WO 2024093109A1
Authority
WO
WIPO (PCT)
Prior art keywords
terminal device
target cell
information
rach
less
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/CN2023/084505
Other languages
English (en)
Inventor
Min Xu
Lianhai WU
Ran YUE
Jing HAN
Jie Hu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lenovo Beijing Ltd
Original Assignee
Lenovo Beijing Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lenovo Beijing Ltd filed Critical Lenovo Beijing Ltd
Priority to PCT/CN2023/084505 priority Critical patent/WO2024093109A1/fr
Publication of WO2024093109A1 publication Critical patent/WO2024093109A1/fr
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0055—Transmission or use of information for re-establishing the radio link
    • H04W36/0072—Transmission or use of information for re-establishing the radio link of resource information of target access point
    • H04W36/00725—Random access channel [RACH]-less handover
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/04—Large scale networks; Deep hierarchical networks
    • H04W84/06—Airborne or Satellite Networks

Definitions

  • Embodiments of the present disclosure generally relate to the field of communication, and in particular to devices, methods, and a non-transitory computer readable medium for RACH-less handover.
  • NTN Non-terrestrial Network
  • the satellite in NTN can be a GEO (Geostationary Earth Orbiting) satellite with fixed location to the Earth, or a LEO (Low Earth Orbiting) satellite orbiting around the Earth.
  • GEO Global System for Mobile Communications
  • LEO Low Earth Orbiting
  • 3GPP Rel-17 specifications have provided basic support of NTN features and in Rel-18 further enhancements including RACH-less handover are to be studied. Due to the large propagation delay and UE number in NTN, the duration of random access procedure is much longer and the contention of random access attempts is severer than that in TN. From this perspective RACH-less HO is considered as an option of skipping random access procedures in NTN.
  • embodiments of the present disclosure provide a solution for RACH-less handover, for example, for performing RACH-less handover in NTN.
  • a terminal device comprising a processor and a transceiver coupled to the processor.
  • the processor is configured to receive, via the transceiver from a network device, information associated with a target cell in a random access channel (RACH) -less handover (HO) procedure; and determine, based on the information, at least one timing parameter for accessing the target cell.
  • RACH random access channel
  • HO handover
  • a network device comprising a processor and a transceiver coupled to the processor.
  • the processor is configured to transmit, via the transceiver to a terminal device, information associated with a target cell in a random access channel (RACH) -less handover (HO) procedure, wherein the information is used for the terminal device to determine at least one timing parameter for accessing the target cell.
  • RACH random access channel
  • HO handover
  • a method performed by a terminal device comprises receiving, via a transceiver from a network device, information associated with a target cell in a random access channel (RACH) -less handover (HO) procedure; and determining, based on the information, at least one timing parameter for accessing the target cell.
  • RACH random access channel
  • HO handover
  • a method performed by a network device comprises transmitting, via a transceiver to a terminal device, information associated with a target cell in a random access channel (RACH) -less handover (HO) procedure, wherein the information is used for the terminal device to determine at least one timing parameter for accessing the target cell.
  • RACH random access channel
  • HO handover
  • a non-transitory computer readable medium having program instructions stored thereon.
  • the program instructions when executed by an apparatus, causing the apparatus at least to: receive, via a transceiver from a network device, information associated with a target cell in a random access channel (RACH) -less handover (HO) procedure; and determine, based on the information, at least one timing parameter for accessing the target cell.
  • RACH random access channel
  • HO handover
  • a non-transitory computer readable medium having program instructions stored thereon.
  • the program instructions when executed by an apparatus, causing the apparatus at least to: transmit, via a transceiver to a terminal device, information associated with a target cell in a random access channel (RACH) -less handover (HO) procedure, wherein the information is used for the terminal device to determine at least one timing parameter for accessing the target cell.
  • RACH random access channel
  • HO handover
  • Fig. 1A illustrates a schematic diagram of a communication environment in which some embodiments of the present disclosure can be implemented
  • Fig. 1B, Fig. 1C, Fig. 1D, and Fig. 1E illustrate schematic diagrams of some examples of application of RACH-less HO in NR NTN;
  • Fig. 2 illustrates a schematic diagram showing a process of communication between a terminal device and a network device in accordance with some embodiments of the present disclosure
  • Fig. 3 illustrates a schematic diagram showing a flow diagram of performing RACH-less HO in accordance with some embodiments of the present disclosure
  • Fig. 4 illustrates a flowchart of an example method performed by a terminal device in accordance with some embodiments of the present disclosure
  • Fig. 5 illustrates a flowchart of an example method performed by a network device in accordance with some embodiments of the present disclosure.
  • Fig. 6 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure.
  • references in the present disclosure to “one embodiment, ” “an example embodiment, ” “an embodiment, ” “some embodiments, ” and the like indicate that the embodiment (s) 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 do not necessarily refer to the same embodiment (s) . 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 other embodiments whether or not explicitly described.
  • first and second or the like 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 element. For example, a first element could also be termed as a second element, and similarly, a second element could also be termed as a first element, without departing from the scope of embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.
  • the term “communication network” refers to a network following any suitable communication standards, such as, 5G NR, 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-IoT) , and so on.
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • WCDMA Wideband Code Division Multiple Access
  • HSPA High-Speed Packet Access
  • NB-IoT Narrow Band Internet of Things
  • 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, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future.
  • any suitable generation communication protocols including but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future.
  • Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will also be future type communication technologies and systems in which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned systems.
  • the term “network device” generally refers to a node in a communication network via which a terminal device can access the communication network and receive 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) , a radio access network (RAN) node, an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , an infrastructure device for a V2X (vehicle-to-everything) communication, a transmission and reception point (TRP) , a reception point (RP) , a remote radio head (RRH) , a relay, an integrated access and backhaul (IAB) node, a low power node such as a femto BS, a pico BS, and so forth, depending on
  • terminal device generally refers to any end device that may be capable of wireless communications.
  • a terminal device may also be referred to as a communication device, a user equipment (UE) , an end user device, a subscriber station (SS) , an unmanned aerial vehicle (UAV) , a portable subscriber station, a mobile station (MS) , or an access terminal (AT) .
  • UE user equipment
  • SS subscriber station
  • UAV unmanned aerial vehicle
  • MS mobile station
  • AT access terminal
  • the terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet, a wearable terminal device, a personal digital assistant (PDA) , a portable computer, a desktop computer, an image capture terminal device such as a digital camera, a gaming terminal device, a music storage and playback appliance, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , a USB dongle, a smart device, 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 (for example, a remote surgery device) , an industrial device (for example, a robot and/or other wireless devices operating in an industrial and/or an automated processing chain
  • the terms “resource, ” “transmission resource, ” “resource block, ” “physical resource block, ” “uplink resource, ” “downlink resource, ” or “sidelink resource” may refer to any resource, for example a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other resource enabling a communication, and the like, used for performing a communication between a terminal device and a network device or between terminal devices.
  • a resource in both frequency and time domain will be used as an example of a transmission resource for describing some embodiments of the present disclosure. It is noted that embodiments of the present disclosure equally apply to other resources in other domains.
  • RACH-less handover is a feature introduced in Rel-14 LTE to allow UE skip random access procedure during handover.
  • UE is able to perform handover to a target cell belonging to the target eNB omitting the random access procedures and establish RRC connection in the target cell using the configured uplink resources. That is, if RACH-less HO is configured, the UE accesses the target cell via the uplink grant pre-allocated to the UE, and if the UE does not receive the pre-allocated uplink grant, the UE monitors the PDCCH of the target cell to obtain a dynamic grant for access.
  • RACH-less HO is a HO mechanism introduced in Rel-14 LTE to skip random access procedure.
  • NTA timing adjustment indication
  • NTA reuse NTA from a source eNB
  • NTA denotes a parameter defined in TS36.213 and TS36.211. If the access towards the target cell (using RACH or RACH-less procedure) is not successful within a certain time, the UE initiates radio link failure recovery using a suitable cell.
  • the UE accesses the target cell via the uplink grant pre-allocated to the UE, or monitors the PDCCH of the target
  • the legacy RACH-less HO introduced in Rel-14 does not consider the impacts of NTN scenario which is introduced in Rel-17.
  • the timing adjustment indication only considers NTA, and its execution and failure handling does not consider TA report, TA calculation, CHO and PCI unchanged case that are NTN-specific.
  • NTN Non-terrestrial Network
  • the satellite in NTN can be a GEO (Geostationary Earth Orbiting) satellite with fixed location to the Earth, or a LEO (Low Earth Orbiting) satellite orbiting around the Earth.
  • GEO Global System for Mobile Communications
  • LEO Low Earth Orbiting
  • RACH-less HO is considered as an option of skipping random access procedures in NTN to reduce the duration and possibility of contention in access.
  • RAN2 asked RAN1 for the possible scenarios and RAN1 confirmed that at least the scenario of intra-satellite HO within the same gNB is possible, and the scenarios of intra-satellite HO between gNBs, inter-satellite HO within the same gNB and inter-satellite HO between gNBs may also be possible, as long as UE uplink transmission synchronization can be maintained by applying correct Timing Advance (TA) pre-compensation in the target cell. Therefore, RAN2#121 meeting confirmed to support RACH-less HO in Rel-18 NTN.
  • TA Timing Advance
  • RAN2#121 meeting confirmed to support RACH-less HO in Rel-18 NTN with the following agreements:
  • Issue #1 To guarantee TA pre-compensation in the target cell as early and accurate as possible, UE needs to obtain necessary information associated to the target cell TA, which is not always available in legacy (Rel-17) NTN and is not supported in legacy RACH-less HO.
  • UE needs to obtain the ephemeris and common TA information of target cell to derive the pre-compensated TA in the target cell.
  • Such information can at least be obtained by receiving corresponding SI (SIB19 for NR and SIB31 for LTE) in the target cell, and may also be obtained by receiving corresponding SI in the source cell, if optionally included.
  • SI SIB19 for NR and SIB31 for LTE
  • UE calculates UE-specific TA and derives common TA of the target cell, both of which are associated to the start of preamble transmission.
  • UE pre-compensates the TA as:
  • UE can obtain necessary information of target cell ephemeris and common TA information before HO, and minimize the calculations to derive the UE-specific and common of the target cell before the occasion of the pre-allocated or monitored uplink grant.
  • target cell ephemeris and common TA information before HO, and minimize the calculations to derive the UE-specific and common of the target cell before the occasion of the pre-allocated or monitored uplink grant.
  • such information is only optionally provided in source cell, and in legacy RACH-less HO, only whether N TA is identical is indicated.
  • Issue #2 An issue that how to handle TA report in the target cell after RACH-less HO wherein random access procedure is skipped, especially for intra-satellite HO case wherein TA could be identical is to be solved.
  • TA report was introduced to allow UE to report its calculated TA in a MAC CE.
  • a TA report can be triggered if:
  • offsetThresholdTA is configured via dedicated signalling and UE has not reported TA to the cell.
  • offsetThresholdTA In CONNECTED state if offsetThresholdTA is configured via dedicated signalling and the TA variation to previous report is larger than offsetThresholdTA.
  • the TA at UE could be updated or not (e.g., inter-satellite or intra-satellite) , and the eNB/gNB of the target cell could be aware of UE’s TA or not (e.g., propagation delay difference report) . It is unclear whether a UE executed RACH-less HO shall follow the TA report mechanisms in Rel-17 NR NTN, e.g., whether UE shall report TA without random access when ta-Report is configured as enabled in SIB19 of target cell, especially for intra-satellite HO wherein TA could be identical, or how UE considers the TA value in previous report to the source cell.
  • Issue #3 One issue is how to handle RACH-less HO failure in NTN including failure due to miscalculation of TA or expiration of ephemeris or common TA information of the target cell, and another issue is how UE maintains the calculated TA for RACH-less HO failure recovery.
  • the UE initiates radio link failure recovery using a suitable cell.
  • the TA for uplink synchronization changes over time and each cell has a limited time duration to provide coverage in certain areas.
  • the RACH-less HO failure may occur due to miscalculation of the TA to the target cell, or due to expiration of ephemeris or common TA information of the target cell.
  • UE may still need the TA to the source cell for recovery, meaning that UE may need to maintain more than one TAs e.g., for the source and target cells.
  • Issue #4 It need to be solved that when CHO and RACH-less HO are configured simultaneously, how does UE monitor PDCCH for dynamic uplink grants with the uncertain timing of CHO execution.
  • a pre-allocated uplink grant could be earlier or much later than CHO execution. In either case whether UE could monitor PDCCH for a dynamic uplink grant instead of the pre-allocated uplink grant.
  • PDCCH monitoring for dynamic uplink grant is not needed before CHO execution.
  • PCI unchanged case can be implemented by NW in same gateway/gNB/feeder link scenarios.
  • UE following legacy mechanisms, UE cannot use uplink grant obtained in source cell for RACH-less HO in target cell, although the PCI and configurations could be the same.
  • 3GPP Rel-18 NTN has just confirmed support on RACH-less HO in NR NTN, and only some potential directions of further study were identified.
  • the communication environment 100 which may be a part of a communication network, comprises a terminal device 110, a network device 120 and a network device 130.
  • the terminal devices 110 and 120 may perform communications with the network device, respectively.
  • the communication link For transmissions from the network device 120 or 130 to the terminal device 110, the communication link may be referred to as a downlink, whereas for transmissions from the terminal device 110 to the network device 120 or 130, the communication link may be referred to as an uplink.
  • the network device 120 and the network device 130 may be in satellites.
  • the terminal device 110 may skip random access procedure during handover from a cell provided by the network device 130 to a cell provided by the network device 120, or vice versa.
  • terminal device 110 and the network devices 120, 130 are described in the communication environment 100 of Fig. 1A, embodiments of the present disclosure may equally apply to any other suitable communication devices in communication with one another. That is, embodiments of the present disclosure are not limited to the exemplary scenarios of Fig. 1A.
  • the terminal devices 110 and 120 are schematically depicted as mobile phones and the network device is schematically depicted as a base station in Fig. 1A, it is understood that these depictions are exemplary in nature without suggesting any limitation.
  • the terminal devices 110 and 120, and the network device may be any other communication devices, for example, any other wireless communication devices.
  • the communication environment 100 may include any suitable number of communication devices and any suitable number of communication links for implementing embodiments of the present disclosure.
  • the communications in the communication environment 100 may follow any suitable communication standards or protocols, which are already in existence or to be developed in the future, such as universal mobile telecommunications system (UMTS) , long term evolution (LTE) , LTE-advanced (LTE-A) , the fifth generation (5G) new radio (NR) , wireless fidelity (Wi-Fi) and worldwide interoperability for microwave access (WiMAX) standards, and employs any suitable communication technologies, including, for example, 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 connectivity (DC) , and new
  • the communication environment 100 may involve NTN.
  • Fig. 1B, Fig. 1C, Fig. 1D, and Fig. 1E illustrate schematic diagrams of some examples of application of RACH-less HO in NR NTN.
  • Fig. 1B, Fig. 1C, Fig. 1D, and Fig. 1E illustrate schematic diagrams of some examples of application of RACH-less HO in NR NTN.
  • Fig. 1B, Fig. 1C, Fig. 1D, and Fig. 1E respectively.
  • intra-satellite at least part of TA in target cell could be identical to the source cell, and for same gateway/gNB/feeder link the target cell PCI could be identical to the source cell as well as cell configurations.
  • Fig. 1A For the first case shown in Fig.
  • intra-satellite and the same gateway or gNB are involved, i.e. handover is performed based on different cells of one gNB corresponding to one satellite.
  • intra-satellite and different gateways or gNBs feeder link switch
  • handover is performed based on different cells of different gNBs corresponding to one satellite.
  • inter-satellite and the same gateway or gNB service link switch
  • handover is performed based on different cells of the same gNB corresponding to different satellites.
  • Fig. 1E inter-satellite and different gateways or gNBs are involved, i.e. handover is performed based on different cells of different gNBs corresponding to different satellites respectively.
  • the network device 120 is shown in Fig. 2. It is to be noted that in some embodiments, the network device 120 in Fig. 2 may be replaced by the network device 130.
  • the network device 120 may be referred to as the first network device 120.
  • the network device 130 may be referred to as the second network device 130.
  • the terminal device 110 may comprise a processor (may be referred to as a first processor, and a transceiver (may be referred to as a first transceiver) coupled to the first processor.
  • the first network device 120 may comprise a processor (may be referred to as a second processor, and a transceiver (may be referred to as a second transceiver) coupled to the second processor.
  • the first network device 120 may transmit (210) , via the second transceiver to the terminal device 110, information 205 associated with a target cell in a random access channel (RACH) -less handover (HO) procedure.
  • the information 205 is used for the terminal device 110 to determine at least one timing parameter for accessing the target cell.
  • the terminal device 110 may receive (220) , via the first transceiver from the first network device 120, the information 205 associated with the target cell in the RACH-less HO procedure.
  • the terminal device 110 may further determine (230) , based on the information 205, at least one timing parameter for accessing the target cell.
  • the first network device 120 in Fig. 2 may be replaced by the second network device 130, as such, there may be a similar process of communication between the terminal device 110 and the second network device 130.
  • the second network device 130 may transmit, via the third transceiver (a transceiver in the second network device 130) to the terminal device 110, information 205 associated with a target cell in a RACH-less HO procedure, wherein the information 205 is used for the terminal device 110 to determine at least one timing parameter for accessing the target cell.
  • the terminal device 110 may receive, via the first transceiver from the second network device 130, the information 205 associated with the target cell in the RACH-less HO procedure, and then the terminal device 110 further determine, based on the information 205, at least one timing parameter for accessing the target cell.
  • the information 205 may comprise at least one reference common timing advance (TA) associated with at least one time point.
  • TA reference common timing advance
  • the at least one time point may be at least one occasion of at least one uplink grant for the RACH-less HO procedure. For the following occurrence of the at least one time point, the illustration will not be repeated.
  • the information 205 may comprise at least one reference terminal device specific TA associated with the at least one time point.
  • the information 205 may comprise common TA information associated with the at least one time point.
  • the information 205 may comprise ephemeris information associated with the at least one time point.
  • the information 205 may be indicated to the terminal device 110 via dedicated signaling.
  • the information 205 may be associated with the target cell TA, and may be indicated to an UE (an example of the terminal device 110) via dedicated signalling.
  • the information 205 may comprise at least one reference common TA value of the target cell each associated with at least one occasion of at least one uplink grant for RACH-less HO.
  • the information 205 may comprise at least one reference UE-specific TA value of the target cell each associated with at least one occasion of at least one uplink grant for RACH-less HO.
  • the at least one reference UE-specific TA value may be derived based on a propagation delay difference reported by the UE and a TA in source cell.
  • the information 205 may comprise common TA information of the target cell associated to at least one occasion of an UL grant for RACH-less HO, with enough validity duration at least to cover the occasion.
  • the information 205 may comprise ephemeris information of the target cell associated to at least one occasion of an UL grant for RACH-less HO, with enough validity duration at least to cover the occasion.
  • the at least one timing parameter may comprise at least one pre-compensated TA associated with the target cell, and the at least one pre-compensated TA may be determined based on at least one common TA and at least one terminal device specific TA derived from the information 205.
  • the terminal device 110 may determine, based on the at least one reference common TA, at least one common TA associated with the at least one time point. In some embodiments, the terminal device 110 may determine, based on the at least one reference terminal device specific TA, at least one terminal device specific TA associated with the at least one time point. For example, the terminal device 110 may determine the at least one reference common TA as the at least one common TA, and determine the at least one reference terminal device specific TA as the at least one terminal device specific TA.
  • the UE may determine at least one common TA value of the target cell associated with at least one occasion of at least one uplink grant for RACH-less HO based on the indicated at least one reference common TA value of the target cell.
  • the UE may also determine at least one UE-specific TA value of the target cell associated to at least one occasion of at least one uplink grant for RACH-less HO based on the indicated at least one reference UE-specific TA value of the target cell.
  • the terminal device 110 may determine, based on the common TA information, at least one common TA associated with the at least one time point. In some embodiments, in order to determine the at least one timing parameter, the terminal device 110 may determine, based on the ephemeris information, at least one terminal device specific TA associated with the at least one time point. For example, the terminal device 110 may calculate the at least one common TA based on the common TA information, and the terminal device 110 may calculate the at least one terminal device specific TA based on the ephemeris information.
  • the UE may derive at least one common TA value of the target cell associated with at least one occasion of at least one uplink grant for RACH-less HO based on the indicated common TA information of the target cell associated to the at least one occasion.
  • the UE may also derive at least one UE-specific TA value of the target cell associated to at least one occasion of at least one uplink grant for RACH-less HO based on the indicated ephemeris of the target cell associated to the at least one occasion.
  • the UE may include the determined or derived common TA value and UE-specific TA value associated to the at least one occasion of at least one uplink grant in the TA to be pre-compensated when transmitting RRC Reconfiguration Complete to the target cell.
  • the terminal device 110 may further determine, at least one pre-compensated TA associated with the target cell.
  • the network device is the first network device 120 providing the target cell.
  • the information 205 may be received via a container message of an HO request acknowledgement from the first network device 120.
  • the information 205 may be transmitted via the container message of an HO request acknowledgement from the first network device 120.
  • the network device is the second network device 130.
  • the information 205 may be received via a radio resource control (RRC) reconfiguration message from the second network device 130 providing the source cell in the RACH-less HO procedure.
  • RRC radio resource control
  • the information 205 may be transmitted via the RRC reconfiguration message from the second network device 130.
  • the first processor may be further configured to report, via the first transceiver to the network device 120 (i.e. the first network device 120) , a compensated TA associated with the target cell, wherein the compensated TA is one of the at least one pre-compensated TA.
  • the first network device 120 may receive, via the second transceiver from the terminal device 110, the report of a compensated TA associated with the target cell.
  • the compensated TA may be a first compensated TA. In some embodiments, the compensated TA may be reported as a value of the compensated TA. In some embodiments, the compensated TA may be reported as a difference between the first compensated TA and a second compensated TA associated with a source cell in the RACH-less HO procedure. For example, for TA report contents, the UE may report the full TA or delta TA (only the updated/changed part or only the updated/changed value) compared to the previous TA report in source cell. It should be noted that the reported TA mentioned in the examples above refers to the compensated TA associated with the target cell.
  • the compensated TA when certain condition is met, the compensated TA may be reported. In some embodiments, the condition may be that the first compensated TA is different from second compensated TA. In some embodiments, the condition may be that a parameter for reporting the first compensated TA is configured as enabled by the network device 120 (i.e. the first network device 120) .
  • the condition may be that the parameter for reporting the first compensated TA is configured as enabled by the network device 120 (i.e. the first network device 120) and the first compensated TA is different from the second compensated TA.
  • the condition may be that the parameter for reporting the first compensated TA is configured as enabled by the network device 120 (i.e. the first network device 120) and either the at least one reference common TA or the at least one reference terminal device specific TA is not indicated by the network device 120.
  • the condition may be that the terminal device 110 is in a connected state and a TA offset threshold is configured. In some embodiments, the condition may be that the terminal device 110 is in the connected state, the TA offset threshold is configured, and the first compensated TA is different from the second compensated TA.
  • the condition may be that the terminal device 110 is in the connected state, the TA offset threshold is configured, and a difference between the first compensated TA and the second compensated TA is larger than the TA offset threshold.
  • the condition may be that the terminal device 110 is in the connected state, the TA offset threshold is configured, and either the at least one reference common TA or the at least one reference terminal device specific TA is not indicated by the network device 120 (i.e. the first network device 120) .
  • the UE may trigger TA reporting in the target cell if:
  • UE derived TA in the target cell has updated (or changed beyond threshold) compared to that in the source cell.
  • ta-Report (an example of the parameter for reporting the first compensated TA) is configured as enabled in SIB19.
  • ta-Report is configured as enabled in SIB19 and UE derived TA in the target cell has updated (or changed beyond threshold) compared to that in the source cell.
  • ta-Report is configured as enabled in SIB19 and either reference common TA or reference UE-specific TA is not indicated by network for the RACH-less HO.
  • offsetThresholdTA an example of the TA offset threshold
  • TA offset threshold is configured via dedicated signalling.
  • offsetThresholdTA is configured via dedicated signalling and UE derived TA in the target cell has updated (or changed beyond offsetThresholdTA) compared to that in the source cell.
  • offsetThresholdTA is configured via dedicated signalling and either reference common TA or reference UE-specific TA is not indicated by network for the RACH-less HO.
  • the first processor may be further configured to maintain a second compensated TA associated with a source cell in the RACH-less HO procedure until the terminal device 110 accesses the target cell successfully, and apply the second compensated TA to access the source cell in the case that the terminal device 110 fails to access the target cell.
  • the UE when performing RACH-less HO in NTN, may maintain at least two TAs each associated to an NTN cell, and the UE does not discard TA of source cell and its associated TimeAlignmentTimer if running or being configured until successful HO (handover) to the target cell, or uses it for failure recovery to the source cell.
  • the first processor may be further configured to maintain a first compensated TA associated with the target cell in the case that the terminal device 110 fails to access the target cell, and apply the first compensated TA for failure recovery to access the target cell.
  • the UE when performing RACH-less HO in NTN, may maintain at least two TAs each associated to an NTN cell, and the UE does not discard TA of the target cell and its associated TimeAlignmentTimer if running or being configured after HO failure, and uses it for failure recovery to target cell.
  • the common TA information may be first common TA information
  • the ephemeris information may be first ephemeris information
  • the first processor may be further configured to receive, via the first transceiver from the network device 120 (i.e.
  • the terminal device 110 fails to access the target cell, determine, based on the second ephemeris information, at least one further terminal device specific TA associated with at least one time point, determine, based on the second common TA information, at least one further common TA associated with at least one time point, determine, based on the at least one further terminal device specific TA and the at least one further common TA, at least one further pre-compensated TA associated with the target cell, and initiate RRC reestablish or random access to the target cell with a TA among the at least one further pre-compensated TA.
  • the UE may re-acquire ephemeris and common TA information of the target cell, and then the UE may re-calculate the TA to be pre-compensated in target cell, and attempt to initiate RRC reestablish or random access to the target cell with the re-calculated TA to be pre-compensated.
  • the first processor may be further configured to prioritize the source cell or the target cell for the RACH-less HO procedure with a TA available for the terminal device 110 to be compensated.
  • the UE may prioritize an NTN cell with calculated TA or ephemeris and common TA information available at the UE.
  • the first processor may be further configured to de-prioritize or preclude the source cell or the target cell for the RACH-less HO procedure with stop serving time to be reached.
  • the UE may de-prioritize or preclude an NTN cell approaching its stop serving time.
  • the first processor may be further configured to report, via the first transceiver to the network device 120 (i.e. the first network device 120) , at least one reasons of failure to access the target cell.
  • the first network device 120 may receive, via the second transceiver from the terminal device 110, the report of at least one reasons of failure to access the target cell.
  • the at least one reasons of failure to access the target cell may comprise miscalculation of a first compensated TA associated with the target cell, additionally or alternatively, the at least one reasons of failure to access the target cell may comprise expiration of ephemeris information or common TA information for determining the first compensated TA. For example, after connection is recovered to the network, the UE may report reason of failure including TA miscalculation or expiration of ephemeris or common TA information to the network.
  • the information 205 may be associated with at least one uplink resource.
  • the first network device 120 may use the at least one uplink resource to receive a connection reconfiguration complete message from the terminal device 110.
  • the first processor may be further configured to perform starting to monitor physical downlink control channel (PDCCH) for dynamic uplink grants indicating an uplink resource for RACH-less HO after conditional handover (CHO) execution is initiated or the CHO execution condition is fulfilled.
  • the first processor may be further configured to perform starting to monitor the PDCCH in the case that at least one occasion of pre-allocated uplink grant indicating an uplink resource for RACH-less HO has passed when the terminal device 110 executes the CHO.
  • the first processor may be further configured to perform starting to monitor the PDCCH in the case that the CHO has been executed and the next occasion of the pre-allocated uplink grant does not occur.
  • the UE may only start to monitor PDCCH for dynamic uplink grants for RACH-less HO after CHO execution is initiated or CHO execution condition is fulfilled.
  • the UE may start to monitor PDCCH for dynamic uplink grants for RACH-less HO.
  • the UE may start to monitor PDCCH for dynamic uplink grants and may use a selected dynamic uplink grant for RACH-less HO with its occasion before the next occasion of pre-allocated uplink grant.
  • the first processor may be further configured to apply an uplink grant corresponding to the source cell obtained before the RACH-less HO procedure as a pre-allocated uplink grant for accessing the target cell.
  • the network device 120 is the first network device 120 providing the target cell, and the first processor may be further configured to receive, via the first transceiver from the second network device 130 providing the source cell in the RACH-less HO procedure, an indication to apply the uplink grant corresponding to the source cell as a pre-allocated uplink grant for accessing the target cell in the RACH-less HO procedure.
  • the UE if it has obtained an uplink grant in the source cell before RACH-less HO, it can be used for RACH-less HO (i.e., to transmit RRC Reconfiguration Complete) without monitoring PDCCH in the target cell.
  • the source cell may indicate the UE to use it as a pre-allocated uplink grant for RACH-less HO.
  • Fig. 3 illustrates a schematic diagram showing a flow diagram of performing RACH-less HO in accordance with some embodiments of the present disclosure. Some previous procedures and conventional steps not shown in Fig. 3. The steps shown in Fig. 3 may be described in further detail with reference to embodiment #1 to embodiment #5.
  • the source BS 303 may transmit a HO request (HO REQ) to the target BS 305.
  • the target BS 305 may transmit a HO request acknowledgement (HO REQ ACK) to the source BS 303.
  • the source BS 303 or the target BS 305 may transmit the information 205 to the UE 301.
  • the source BS 303 may transmit, to the UE 301, the information 205 via a radio resource control (RRC) reconfiguration message.
  • the target BS 305 may transmit, to the UE 301, the information via a container message of a HO REQ ACK.
  • the UE 301 may determine common TA and UE-specific TA value of the target cell associated to grant occasion. The operations corresponding to 306, 308 and 310 may be further described in Embodiment #1 below.
  • the UE 301 may use pre-allocated UL grant, or monitor PDCCH to receive UL grant if the UL grant is not pre-allocated.
  • CHO execution may be considered during PDCCH monitoring, specifically, there may be 3 options, they are described in Embodiment #2 below.
  • the UE 301 skip RACH and perform uplink transmission synchronization with the target BS 305.
  • the target BS 305 transmits pre-allocated uplink grant if RACH-less HO is configured.
  • the uplink grant may be allocated periodically.
  • the UE 301 may trigger TA report based on one or more conditions are met.
  • the conditions may be further described in embodiment #3 below.
  • the UE 301 may apply the uplink grant corresponding to the source BS 303 as a pre-allocated uplink grant for accessing the target BS 305, i.e. the uplink grant may be inherited.
  • the operations corresponding to 320 may be further described in Embodiment #4 below.
  • the UE 301 may transmit a RRC reconfiguration complete message after the UE 301 has received UL grant.
  • the UE 301 may perform a RACH-less HO failure handling process.
  • the operations corresponding to 324 may be further described in Embodiment #5 below.
  • the present disclosure may solve the potential issues of applying RACH-less HO in NTN scenarios, and guarantee feasible RACH-less HO procedures to reduce the access latency and contention possibility in NTN.
  • the proposed solutions allow the BS to indicate the UE necessary information to derive an accurate TA compensated to access the target cell with minimum calculations, and ensure uplink synchronization at least to one cell upon successful or failed HO execution.
  • the proposed solutions also maximize the uplink resource that can be used by the UE in RACH-less HO to reduce the access latency or signalling overhead.
  • the target cell of RACH-less HO may provide the UE in the container message of HO REQ ACK with at least one of the following:
  • At least one reference associated to at least one occasion of at least one uplink grant for RACH-less HO. could be an absolute value or a relative value compared to of source cell.
  • At least one reference associated to at least one occasion of at least one uplink grant for RACH-less HO which can be derived based on UE reported propagation delay difference and TA in source cell. could be an absolute value or a relative value compared to of source cell.
  • the UE may obtain at least one uplink grant (pre-allocated uplink grant or a dynamic uplink grant monitored in PDCCH) for RACH-less HO, and derives the pre-compensated TA associated to at least one occasion of at least one uplink grant as wherein:
  • t grant is a time point associated to the selected at least one uplink grant for RACH-less HO, e.g., t grant is UE-BS RTT before at least one occasion of the at least one uplink grant.
  • the target cell as the distance between UE and the target cell satellite position at t grant divided by the speed of light.
  • the UE transmits RRC Reconfiguration Complete to the network at the time which is T TA, target before at least one occasion of the at least one uplink grant.
  • Embodiment #1 A specification implementation of Embodiment #1 may be as follows:
  • CHO execution may be considered during PDCCH monitoring, and the following options may be provided.
  • the UE may only start to monitor PDCCH for dynamic uplink grants for RACH-less HO after CHO execution is initiated or CHO execution condition is fulfilled.
  • Option 2 if at least one occasion of pre-allocated uplink grant has passed when the UE executes CHO, the UE starts to monitor PDCCH for dynamic uplink grants for RACH-less HO.
  • Option 3 if the next occasion of pre-allocated uplink grant does not approach when the UE executes CHO, the UE may start to monitor PDCCH for dynamic uplink grants and may use a selected dynamic uplink grant for RACH-less HO with its occasion before the next occasion of pre-allocated uplink grant.
  • the UE triggers TA report in target cell if one of the following conditions is fulfilled:
  • UE derived TA in the target cell has updated (or changed beyond threshold) compared to that in the source cell.
  • ta-Report is configured as enabled in SIB19.
  • ta-Report is configured as enabled in SIB19 and UE derived TA in the target cell has updated (or changed beyond threshold) compared to that in the source cell.
  • ta-Report is configured as enabled in SIB19 and either reference common TA or reference UE-specific TA is not indicated by network for the RACH-less HO.
  • offsetThresholdTA is configured via dedicated signalling.
  • offsetThresholdTA is configured via dedicated signalling and UE derived TA in the target cell has updated (or changed beyond offsetThresholdTA) compared to that in the source cell.
  • offsetThresholdTA is configured via dedicated signalling and either reference common TA or reference UE-specific TA is not indicated by network for the RACH-less HO.
  • UE may report the full TA or delta TA which includes only the updated/changed part or only the updated/changed value compared to the previous TA report in source cell.
  • the obtained uplink grant can be used for RACH-less HO (i.e., to transmit RRC Reconfiguration Complete) without monitoring PDCCH in the target cell.
  • the source cell may indicate the UE to use it as a pre-allocated uplink grant for RACH-less HO.
  • the UE when performing RACH-less HO in NTN, the UE may maintain at least two TAs each associated to an NTN cell, including:
  • UE does not discard TA of source cell and its associated TimeAlignmentTimer if running or being configured until successful HO to target cell, or uses it for failure recovery to source cell.
  • UE does not discard TA of target cell and its associated TimeAlignmentTimer if running or being configured after HO failure, and uses it for failure recovery to source cell.
  • UE may re-acquire ephemeris and common TA information of the target cell
  • UE re-calculates the TA to be pre-compensated in target cell
  • UE attempts to initiate RRC reestablish or random access to the target cell with the re-calculated TA to be pre-compensated.
  • UE prioritizes an NTN cell with calculated TA or ephemeris and common TA information available at UE.
  • UE de-prioritizes or precludes an NTN cell approaching its stop serving time.
  • the UE may report reason of failure including TA miscalculation or expiration of ephemeris or common TA information to the network.
  • Fig. 4 illustrates a flowchart of an example method 400 performed by the terminal device 110 in accordance with some embodiments of the present disclosure.
  • the terminal device 110 may receive, via a transceiver from the network device 120 or 130, information 205 associated with a target cell in a random access channel (RACH) -less handover (HO) procedure.
  • RACH random access channel
  • HO -less handover
  • the terminal device 110 may determine, based on the information 205, at least one timing parameter for accessing the target cell.
  • the information 205 may comprise at least one reference common timing advance (TA) associated with at least one time point, or at least one reference terminal device specific TA associated with the at least one time point, or common TA information associated with the at least one time point, or ephemeris information associated with the at least one time point, or one or more above.
  • TA common timing advance
  • the terminal device 110 may determine, based on the at least one reference common TA, at least one common TA associated with the at least one time point, or determine, based on the at least one reference terminal device specific TA, at least one terminal device specific TA associated with the at least one time point, or determine both above.
  • the terminal device 110 may determine, based on the common TA information, at least one common TA associated with the at least one time point, or determine, based on the ephemeris information, at least one terminal device specific TA associated with the at least one time point, or determine both above.
  • the terminal device 110 may further determine, based on the at least one common TA and the at least one terminal device specific TA, at least one pre-compensated TA associated with the target cell.
  • the network device above is a first network device 120 providing the target cell.
  • the information 205 may be received via a container message of an HO request acknowledgement from the first network device 120, or the information 205 may be received via a radio resource control (RRC) reconfiguration message from the second network device 130 providing a source cell in the RACH-less HO procedure, or the information 205 may be received via both above.
  • RRC radio resource control
  • the terminal device 110 may report, via the transceiver to the first network device 120, a compensated TA associated with the target cell, wherein the compensated TA is one of the at least one pre-compensated TA.
  • the compensated TA may be a first compensated TA and is reported as a value of the compensated TA, or a difference between the first compensated TA and a second compensated TA associated with a source cell in the RACH-less HO procedure.
  • the terminal device 110 may report the compensated TA based on one of a plurality of conditions, and the plurality of conditions comprises: the first compensated TA is different from second compensated TA; a parameter for reporting the first compensated TA is configured as enabled by the first network device 120; the parameter for reporting the first compensated TA is configured as enabled by the first network device 120 and the first compensated TA is different from the second compensated TA;the parameter for reporting the first compensated TA is configured as enabled by the first network device 120 and either the at least one reference common TA or the at least one reference terminal device specific TA is not indicated by the first network device 120; the terminal device 110 is in a connected state and a TA offset threshold is configured; the terminal device 110 is in the connected state, the TA offset threshold is configured, and the first compensated TA is different from the second compensated TA; the terminal device 110 is in the connected state, the TA offset threshold is configured, and a difference between the first compensated TA and the second compensated TA is larger than
  • the terminal device 110 may maintain a second compensated TA associated with the source cell in the RACH-less HO procedure until the terminal device 110 accesses the target cell successfully, and apply the second compensated TA to access the source cell in the case that the terminal device 110 fails to access the target cell.
  • the terminal device 110 may maintain a first compensated TA associated with the target cell in the case that the terminal device 110 fails to access the target cell, and apply the first compensated TA for failure recovery to access the target cell.
  • the common TA information may be first common TA information
  • the ephemeris information may be first ephemeris information.
  • the terminal device 110 may receive, via the transceiver from the network device 120 or 130, second ephemeris information and second common TA information, in the case that the terminal device 110 fails to access the target cell; determine, based on the second ephemeris information, at least one further terminal device specific TA associated with at least one time point; determine, based on the second common TA information, at least one further common TA associated with at least one time point; determine, based on the at least one further terminal device specific TA and the at least one further common TA, at least one further pre-compensated TA associated with the target cell; and initiate RRC reestablish or random access to the target cell with a TA among the at least one further pre-compensated TA.
  • the at least one time point may be at least one occasion of at least one uplink grant for the RACH-less HO procedure.
  • the terminal device 110 may prioritize a source cell or a target cell for the RACH-less HO procedure with a TA available for the terminal device 110 to be compensated. In some embodiments, the terminal device 110 may de-prioritize or preclude a source cell or a target cell for the RACH-less HO procedure with stop serving time to be reached.
  • the terminal device 110 may report, via the transceiver to the first network device 120, at least one reasons of failure to access the target cell.
  • the at least one reasons of failure to access the target cell may comprise miscalculation of a first compensated TA associated with the target cell, or expiration of ephemeris information or common TA information for determining the first compensated TA, or both above.
  • the information 205 may be associated with at least one uplink resource.
  • the terminal device 110 may start to monitor physical downlink control channel (PDCCH) for dynamic uplink grants indicating an uplink resource for RACH-less HO after conditional handover (CHO) execution is initiated or the CHO execution condition is fulfilled. Additionally, or alternatively, the terminal device 110 may start to monitor the PDCCH in the case that at least one occasion of pre-allocated uplink grant indicating an uplink resource for RACH-less HO has passed when the terminal device 110 executes the CHO. Additionally, or alternatively, the terminal device 110 may start to monitor the PDCCH in the case that the CHO has been executed and the next occasion of the pre-allocated uplink grant does not occur.
  • PDCCH physical downlink control channel
  • CHO conditional handover
  • the terminal device 110 may apply an uplink grant corresponding to a source cell obtained before the RACH-less HO procedure as a pre-allocated uplink grant for accessing the target cell.
  • the network device above may be the first network device 120 providing the target cell.
  • the terminal device 110 may receive, via the transceiver from the second network device 130 providing a source cell in the RACH-less HO procedure, an indication to apply the uplink grant corresponding to the source cell as a pre-allocated uplink grant for accessing the target cell in the RACH-less HO procedure.
  • Fig. 5 illustrates a flowchart of an example method 500 performed by the network device 120 or 130 in accordance with some embodiments of the present disclosure.
  • the network device 120 or 130 may transmit, via a transceiver to the terminal device 110, information 205 associated with a target cell in a random access channel (RACH) -less handover (HO) procedure, wherein the information 205 is used for the terminal device 110 to determine at least one timing parameter for accessing the target cell.
  • RACH random access channel
  • HO handover
  • the network device performing the method 500 may be the first network device 120 providing the target cell, and the information 205 may be transmitted via a container message of a HO request acknowledgement from the first network device 120.
  • the network device performing the method 500 may be the second network device 130 providing a source cell in the RACH-less HO procedure, and the information 205 may be transmitted via a radio resource control (RRC) reconfiguration message from the second network device 130.
  • RRC radio resource control
  • the information 205 may comprise at least one reference common timing advance (TA) associated with at least one time point, or at least one reference terminal device specific TA associated with the at least one time point, or common TA information associated with the at least one time point, or ephemeris information associated with the at least one time point, or one or more above.
  • TA common timing advance
  • the at least one time point may be at least one occasion of at least one uplink grant for the RACH-less HO procedure.
  • the at least one timing parameter may comprise at least one pre-compensated TA associated with the target cell, and the at least one pre-compensated TA may be determined based on at least one common TA and at least one terminal device specific TA derived from the information 205.
  • the network device performing the method 500 may be the first network device 120 providing the target cell.
  • the network device 120 may receive, via the transceiver from the terminal device 110, a report of a compensated TA associated with the target cell, wherein the compensated TA is one of the at least one pre-compensated TA.
  • the compensated TA may be a first compensated TA.
  • the first compensated TA may be reported as a value of the compensated TA, or a difference between the first compensated TA and a second compensated TA associated with a source cell in the RACH-less HO procedure.
  • the network device performing the method 500 may be the first network device 120 providing the target cell.
  • the first network device 120 may receive, via the transceiver from the terminal device 110, a report of at least one reasons of failure to access the target cell.
  • the at least one reasons of failure to access the target cell may comprise miscalculation of a first compensated TA associated with the target cell, or expiration of ephemeris information or common TA information for determining the first compensated TA.
  • the information 205 may be associated with at least one uplink resource for receiving a connection reconfiguration complete message from the terminal device 110.
  • FIG. 6 illustrates a simplified block diagram of a device 600 that is suitable for implementing embodiments of the present disclosure.
  • the device 600 can be considered as a further example implementation of the terminal device 110 or the network device 120 or 130 as shown in Fig. 1A. Accordingly, the device 600 can be implemented at or as at least a part of the terminal device 110 or the network device 120 or 130.
  • the device 600 includes a processor 610, a memory 620 coupled to the processor 610, a suitable transmitter (TX) and receiver (RX) 640 coupled to the processor 610, and a communication interface coupled to the TX/RX 640.
  • the memory 610 stores at least a part of a program 630.
  • the TX/RX 640 is for bidirectional communications.
  • the TX/RX 640 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this disclosure may have several ones.
  • the communication interface may represent any interface that is necessary for communication with other network elements, such as X2 interface for bidirectional communications between eNBs or gNBs, S1 interface for communication between a Mobility Management Entity (MME) /Serving Gateway (S-GW) and the eNB or gNB, Un interface for communication between the eNB or gNB and a relay node (RN) , or Uu interface for communication between the eNB or gNB and a terminal device 110.
  • MME Mobility Management Entity
  • S-GW Serving Gateway
  • Un interface for communication between the eNB or gNB and a relay node (RN)
  • Uu interface for communication between the eNB or gNB and a terminal device 110.
  • the program 630 is assumed to include program instructions that, when executed by the associated processor 610, enable the device 600 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to Figs. 1-6.
  • the embodiments herein may be implemented by computer software executable by the processor 610 of the device 600, or by hardware, or by a combination of software and hardware.
  • the processor 610 may be configured to implement various embodiments of the present disclosure.
  • a combination of the processor 610 and memory 620 may form processing means 650 adapted to implement various embodiments of the present disclosure.
  • the memory 620 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 620 is shown in the device 600, there may be several physically distinct memory modules in the device 600.
  • the processor 610 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples.
  • the device 600 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.
  • an apparatus capable of performing the method 500 or 600 may comprise means for performing the respective steps of the method 400 or 500.
  • the means may be implemented in any suitable form.
  • the means may be implemented in a circuitry or software module.
  • 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 method 400 or 500.
  • 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 representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods 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.
  • 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 the process or method as described above.
  • 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.
  • 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.
  • the above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
  • the machine readable medium may be a machine readable signal medium or a machine readable storage medium.
  • a machine 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 the foregoing.
  • machine readable storage medium More specific examples of the machine 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.
  • RAM random access memory
  • ROM read-only memory
  • EPROM or Flash memory erasable programmable read-only memory
  • CD-ROM portable compact disc read-only memory
  • magnetic storage device or any suitable combination of the foregoing.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Des modes de réalisation de la présente invention concernent des dispositifs, des procédés et un support non transitoire lisible par ordinateur pour un transfert sans RACH. Un dispositif terminal reçoit, par l'intermédiaire d'un émetteur-récepteur en provenance d'un dispositif de réseau, des informations associées à une cellule cible dans une procédure de transfert intercellulaire (HO) sans canal d'accès aléatoire (RACH) ; et détermine, sur la base des informations, au moins un paramètre de synchronisation pour accéder à la cellule cible. De cette manière, des procédures de HO sans RACH faisables sont garanties, et la latence d'accès et la possibilité de contention dans les réseaux non terrestres peuvent être réduites.
PCT/CN2023/084505 2023-03-28 2023-03-28 Dispositifs et procédés de transfert sans rach Pending WO2024093109A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2023/084505 WO2024093109A1 (fr) 2023-03-28 2023-03-28 Dispositifs et procédés de transfert sans rach

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2023/084505 WO2024093109A1 (fr) 2023-03-28 2023-03-28 Dispositifs et procédés de transfert sans rach

Publications (1)

Publication Number Publication Date
WO2024093109A1 true WO2024093109A1 (fr) 2024-05-10

Family

ID=90929565

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2023/084505 Pending WO2024093109A1 (fr) 2023-03-28 2023-03-28 Dispositifs et procédés de transfert sans rach

Country Status (1)

Country Link
WO (1) WO2024093109A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN120897242A (zh) * 2025-09-25 2025-11-04 荣耀终端股份有限公司 通信方法及相关装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200389886A1 (en) * 2018-02-14 2020-12-10 Lg Electronincs Inc. Method and apparatus for supporting rach-less mobility with pre-allocated beams in wireless communication system
CN112425218A (zh) * 2018-07-19 2021-02-26 华为技术有限公司 用于通用无rach移动性的方法和系统
CN113518473A (zh) * 2020-04-09 2021-10-19 上海诺基亚贝尔股份有限公司 随机接入信道的增强报告
CN113940114A (zh) * 2019-03-28 2022-01-14 苹果公司 增强的无rach切换
US20220361062A1 (en) * 2019-07-30 2022-11-10 Nokia Technologies Oy Apparatus, method and computer program for handover

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200389886A1 (en) * 2018-02-14 2020-12-10 Lg Electronincs Inc. Method and apparatus for supporting rach-less mobility with pre-allocated beams in wireless communication system
CN112425218A (zh) * 2018-07-19 2021-02-26 华为技术有限公司 用于通用无rach移动性的方法和系统
CN113940114A (zh) * 2019-03-28 2022-01-14 苹果公司 增强的无rach切换
US20220361062A1 (en) * 2019-07-30 2022-11-10 Nokia Technologies Oy Apparatus, method and computer program for handover
CN113518473A (zh) * 2020-04-09 2021-10-19 上海诺基亚贝尔股份有限公司 随机接入信道的增强报告

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN120897242A (zh) * 2025-09-25 2025-11-04 荣耀终端股份有限公司 通信方法及相关装置

Similar Documents

Publication Publication Date Title
US11350325B2 (en) Signaling of delta configuration for handover
US12010659B2 (en) Techniques for a radio access network entity to adjust timing in wireless networks
US10568010B2 (en) Techniques to support ultra-reliable handover in wireless networks
US20230284221A1 (en) Method, device and computer storage medium for communication
JP2023508160A (ja) 通信のための方法、ユーザ装置及び基地局
US12464422B2 (en) Serving cell change procedure utilizing multiple candidate target cells
WO2024093139A1 (fr) Dispositifs, procédés et supports pour communications
WO2024093109A1 (fr) Dispositifs et procédés de transfert sans rach
WO2023206105A1 (fr) Procédé, dispositif et support lisible par ordinateur pour des communications
WO2020014833A1 (fr) Rétablissement après défaillance de faisceau
US20240064601A1 (en) Methods, devices, and computer readable medium for communication
WO2023279332A1 (fr) Procédé, dispositif et support lisible par ordinateur pour la communication
US20230292191A1 (en) Mechanism for cell identity management
WO2025030403A1 (fr) Rapport d'avance temporelle
EP4507381A1 (fr) Changement conditionnel de cellule
WO2024229837A1 (fr) Dispositifs et procédés de communication
WO2024093154A1 (fr) Dispositifs et procédés de communication
US20250056339A1 (en) Methods, devices, apparatuses and medium for measurement-based tci state activation
WO2025166586A1 (fr) Migration mobile d'accès intégré et de liaison terrestre (iab)
WO2025097319A1 (fr) Fourniture de ressource préconfigurée pour une cellule cible dans un réseau non terrestre
US20250234253A1 (en) Conditional cell change
WO2024093187A1 (fr) Dispositifs et procédés dans un environnement à double connectivité multi-radio (mr-dc)
WO2024093115A1 (fr) Dispositifs et procédés de communication
WO2024093097A1 (fr) Dispositifs de communication et procédés de communication
WO2024093119A1 (fr) Dispositifs et procédés de gestion de collision

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23884053

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE