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WO2025081313A1 - Dispositifs et procédés de communication - Google Patents

Dispositifs et procédés de communication Download PDF

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Publication number
WO2025081313A1
WO2025081313A1 PCT/CN2023/124796 CN2023124796W WO2025081313A1 WO 2025081313 A1 WO2025081313 A1 WO 2025081313A1 CN 2023124796 W CN2023124796 W CN 2023124796W WO 2025081313 A1 WO2025081313 A1 WO 2025081313A1
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WO
WIPO (PCT)
Prior art keywords
cell
measurement result
layer
reference signal
candidate cell
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/CN2023/124796
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English (en)
Inventor
Da Wang
Lin Liang
Gang Wang
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NEC Corp
Original Assignee
NEC Corp
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Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to PCT/CN2023/124796 priority Critical patent/WO2025081313A1/fr
Publication of WO2025081313A1 publication Critical patent/WO2025081313A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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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
    • H04W36/0083—Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point
    • H04W36/085—Reselecting an access point involving beams of access points
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point
    • H04W36/087—Reselecting an access point between radio units of access points
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/34—Reselection control
    • H04W36/36—Reselection control by user or terminal equipment
    • H04W36/362—Conditional handover

Definitions

  • Embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to devices and methods of communication for layer 1 (L1) /layer 2 (L2) triggered mobility (LTM) .
  • L1 layer 1
  • L2 layer 2
  • LTM triggered mobility
  • LTM is a procedure in which a network device receives a L1 measurement report from a terminal device, and changes the terminal device’s serving cell by a cell switch command signaled via a medium access control (MAC) control element (CE) .
  • the LTM procedure may be used to reduce mobility latency.
  • MAC medium access control
  • CE control element
  • conditional LTM a cell switch is not triggered by the MAC CE, but by a condition fulfilled at the terminal device side.
  • implementation of conditional LTM is still unclear.
  • embodiments of the present disclosure provide methods, devices and computer storage media of communication for conditional LTM.
  • a terminal device comprising a processor.
  • the processor is configured to cause the terminal device to: in accordance with a determination that an L1 measurement result for at least one beam or reference signal in a list of beams or reference signals associated with a candidate cell allowing LTM fulfills a first condition, determine that an execution condition for a cell switch to the candidate cell is fulfilled; and perform the cell switch to the candidate cell.
  • a distributed unit (DU) of a network device comprises a processor.
  • the processor is configured to cause the DU to: receive, from a center unit (CU) of the network device, information of a cell switch to a candidate cell allowing LTM, the information of the cell switch comprising an indication that the cell switch to the candidate cell is conditional; and transmit, to the CU, a configuration of an execution condition for the cell switch to the candidate cell.
  • CU center unit
  • a CU of a network device comprises a processor.
  • the processor is configured to cause the CU to: transmit, to a DU of the network device, information of a cell switch to a candidate cell allowing LTM, the information of the cell switch comprising an indication that the cell switch to the candidate cell is conditional; and receive, from the DU, a configuration of an execution condition for the cell switch to the candidate cell.
  • a method of communication comprises: in accordance with a determination that an L1 measurement result for at least one beam or reference signal in a list of beams or reference signals associated with a candidate cell allowing LTM fulfills a first condition, determining, at a terminal device, that an execution condition for a cell switch to the candidate cell is fulfilled; and performing the cell switch to the candidate cell.
  • a method of communication comprises: receiving, at a DU of a network device and from a CU of the network device, information of a cell switch to a candidate cell allowing LTM, the information of the cell switch comprising an indication that the cell switch to the candidate cell is conditional; and transmitting, to the CU, a configuration of an execution condition for the cell switch to the candidate cell.
  • a method of communication comprises: transmitting, at a CU of a network device and to a DU of the network device, information of a cell switch to a candidate cell allowing LTM, the information of the cell switch comprising an indication that the cell switch to the candidate cell is conditional; and receiving, from the DU, a configuration of an execution condition for the cell switch to the candidate cell.
  • a computer readable medium having instructions stored thereon.
  • the instructions when executed on at least one processor, cause the at least one processor to perform the method according to any of the fourth to sixth aspects of the present disclosure.
  • FIG. 1A illustrates an example communication network in which some embodiments of the present disclosure can be implemented
  • FIG. 1B illustrates a schematic diagram illustrating network protocol layer entities that may be established for a user plane (UP) protocol stack at devices according to some embodiments of the present disclosure
  • FIG. 1C illustrates a schematic diagram illustrating network protocol layer entities that may be established for a control plane (CP) protocol stack at devices according to some embodiments of the present disclosure
  • FIG. 1D illustrates a signaling chart illustrating an example process of conditional LTM in which some embodiments of the present disclosure can be implemented
  • FIG. 1E illustrates a signaling chart illustrating an example process of LTM candidate preparation for an intra-DU scenario in which some embodiments of the present disclosure can be implemented
  • FIG. 1F illustrates a signaling chart illustrating an example process of LTM candidate preparation for an inter-DU scenario in which some embodiments of the present disclosure can be implemented
  • FIG. 2 illustrates a signaling chart illustrating an example process of communication for conditional LTM according to embodiments of the present disclosure
  • FIG. 3 illustrates a signaling chart illustrating another example process of communication for conditional LTM according to embodiments of the present disclosure
  • FIG. 4 illustrates a flowchart of an example method of communication implemented at a terminal device in accordance with some embodiments of the present disclosure
  • FIG. 5 illustrates a flowchart of an example method of communication implemented at a DU of a network device in accordance with some embodiments of the present disclosure
  • FIG. 6 illustrates a flowchart of an example method of communication implemented at a CU of a network device in accordance with some embodiments of the present disclosure.
  • FIG. 7 illustrates a simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure.
  • terminal device refers to any device having wireless or wired communication capabilities.
  • the terminal device include, but not limited to, user equipment (UE) , personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs) , portable computers, tablets, wearable devices, internet of things (IoT) devices, Ultra-reliable and Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, device on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, devices for Integrated Access and Backhaul (IAB) , Space borne vehicles or Air borne vehicles in Non-terrestrial networks (NTN) including Satellites and High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) , eXtended Reality (XR) devices including different types of realities such as Augmented Reality (AR) , Mixed Reality (MR) and Virtual Reality (VR) , the unmanned aerial vehicle (UAV)
  • UE user equipment
  • the ‘terminal device’ can further has “multicast/broadcast” feature, to support public safety and mission critical, V2X applications, transparent IPv4/IPv6 multicast delivery, IPTV, smart TV, radio services, software delivery over wireless, group communications and IoT applications. It may also incorporate one or multiple Subscriber Identity Module (SIM) as known as Multi-SIM.
  • SIM Subscriber Identity Module
  • the term “terminal device” can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.
  • network device refers to a device which is capable of providing or hosting a cell or coverage where terminal devices can communicate.
  • a network device include, but not limited to, a Node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNB) , a transmission reception point (TRP) , a remote radio unit (RRU) , a radio head (RH) , a remote radio head (RRH) , an IAB node, a low power node such as a femto node, a pico node, a reconfigurable intelligent surface (RIS) , and the like.
  • NodeB Node B
  • eNodeB or eNB evolved NodeB
  • gNB next generation NodeB
  • TRP transmission reception point
  • RRU remote radio unit
  • RH radio head
  • RRH remote radio head
  • IAB node a low power node such as a fe
  • the terminal device or the network device may have Artificial intelligence (AI) or Machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.
  • AI Artificial intelligence
  • Machine learning capability it generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.
  • the terminal or the network device may work on several frequency ranges, e.g. FR1 (410 MHz to 7125 MHz) , FR2 (24.25GHz to 71GHz) , frequency band larger than 100GHz as well as Tera Hertz (THz) . It can further work on licensed/unlicensed/shared spectrum.
  • the terminal device may have more than one connections with the network devices under Multi-Radio Dual Connectivity (MR-DC) application scenario.
  • MR-DC Multi-Radio Dual Connectivity
  • the terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.
  • test equipment e.g. signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, channel emulator.
  • the terminal device may be connected with a first network device and a second network device.
  • One of the first network device and the second network device may be a master node and the other one may be a secondary node.
  • the first network device and the second network device may use different radio access technologies (RATs) .
  • the first network device may be a first RAT device and the second network device may be a second RAT device.
  • the first RAT device is eNB and the second RAT device is gNB.
  • Information related with different RATs may be transmitted to the terminal device from at least one of the first network device or the second network device.
  • first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device.
  • information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device.
  • Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.
  • values, procedures, or apparatus are referred to as “best, ” “lowest, ” “highest, ” “minimum, ” “maximum, ” or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.
  • a connected state may be interchangeably used with “an RRC_CONNECTED state”
  • the term “an idle state” may be interchangeably used with “an RRC_IDLE state”
  • the term “an inactive state” may be interchangeably used with “an RRC_INACTIVE state” .
  • the term “above” herein may be interchangeably used with “higher than or equal to” or “greater than or equal to”
  • the term “below” herein may be interchangeably used with “lower than or equal to” or “smaller than or equal to” .
  • a cell switch may be interchangeably used with “reconfiguration with sync for secondary cell group (SCG) or master cell group (MCG) ” or “a cell change” .
  • the term “primary secondary cell (PSCell) ” refers to a special cell (SpCell) of a SCG
  • the term “primary cell (PCell) ” refers to a SpCell of a MCG
  • the term “SpCell” refers to a primary cell of a SCG or MCG.
  • secondary cell (SCell) refers to a secondary cell.
  • the term “lower-layer signaling” may be interchangeably used with “L1/L2 signaling” .
  • RRC reconfiguration may be interchangeably used with “RRC reconfiguration message” .
  • candidate cell may be interchangeably used with “LTM candidate cell” or “candidate cell allowing LTM” .
  • target cell may be interchangeably used with “target candidate cell” , “candidate target cell” , or “LTM target candidate cell” .
  • L1 measurement may be interchangeably used with “physical layer measurement” .
  • time window may be interchangeably used with “average window” .
  • a serving cell change may need to be performed at some point.
  • a serving cell change is triggered by layer 3 (L3) measurements and is done by an RRC signaling triggered reconfiguration with synchronization for change of PCell and PSCell. All these cases involve complete L2 (and L1) resets, leading to longer latency, larger overhead and longer interruption time than beam switch mobility.
  • LTM is to enable a serving cell change via L1/L2 signaling, in order to reduce the latency, overhead and interruption time.
  • LTM is a procedure in which a network device (e.g., gNB) receives L1 measurement report (s) from a terminal device (e.g., UE) , and on their basis the network device changes the terminal device’s serving cell by a cell switch command signaled via a MAC CE.
  • the cell switch command indicates an LTM candidate cell configuration that the network device previously prepared and provided to the terminal device through an RRC signaling. Then the terminal device switches to a target cell according to the cell switch command.
  • the network device indicates in the cell switch command whether the terminal device accesses the target cell with a random access (RA) procedure if a timing advance (TA) value is not provided or with a physical uplink shared channel (PUSCH) transmission using an indicated TA value.
  • RA random access
  • TA timing advance
  • PUSCH physical uplink shared channel
  • the terminal device may access the target cell via a configured grant (CG) provided in the RRC signaling and selects a CG occasion associated with a beam indicated in the cell switch command. If the terminal device does not receive the CG in the RRC signaling, the terminal device may monitor a physical downlink control channel (PDCCH) for dynamic scheduling from the target cell upon LTM cell switch.
  • CG configured grant
  • PDCCH physical downlink control channel
  • conditional LTM is proposed.
  • a cell switch is not triggered by an MAC CE, but by a condition fulfilled at a terminal device side.
  • implementation of conditional LTM is still unclear.
  • Embodiments of the present disclosure provide solutions of communication for conditional LTM.
  • a terminal device determines that an execution condition for a cell switch to the candidate cell is fulfilled, and performs the cell switch to the candidate cell. In this way, a conditional LTM cell switch may be triggered and executed.
  • a CU of a network device transmits, to a DU of the network device, information of a cell switch to a candidate cell allowing LTM.
  • the information of the cell switch comprises an indication that the cell switch to the candidate cell is conditional.
  • the DU then transmits, to the CU, a configuration of an execution condition for the cell switch to the candidate cell. In this way, an execution condition for an LTM cell switch may be generated by a DU, and implementation of conditional LTM may be facilitated.
  • FIG. 1A illustrates a schematic diagram of an example communication network 100A in which some embodiments of the present disclosure can be implemented.
  • the communication network 100A may include a terminal device 110 and network devices 120 and 130.
  • the network device 120 may provide one or more cells (cells 122-1, 122-2, 123-1, and 123-2 as shown) to serve one or more terminal devices.
  • the network device 130 may also provide one or more cells (not shown) to serve one or more terminal devices.
  • the network device 120 may comprise a CU 121 and DUs 122 and 123.
  • the CU 121 may communicate with the DUs 122 and 123. It is to be understood that the two DUs 122 and 123 are shown only for illustration, and more or less DUs may also be provided for implementation of embodiments of the present disclosure.
  • the DU 122 provides the cells 122-1 and 122-2 and the DU 123 provides the cells 123-1 and 123-2. It is to be understood that this is merely an example, and any of the DUs 122 and 123 may provide more or less cells.
  • the terminal device 110 may communicate with any of these cells. In this example, the terminal device 110 is located in the cell 123-1 and served by the network device 120.
  • the network device 130 may comprise a CU and one or more DUs as described in connection with the network device 120.
  • the network device 130 may not be implemented in a CU-DU architecture, and may be implemented in an integrated architecture as shown.
  • the communication network 100A may further include a core network (CN) 135.
  • the terminal device 110 may communicate with the CN 135 via the network device 120 and/or the network device 130.
  • the terminal device 110 may communicate with the CU 121 via the DU 123 and the CU 121 may further communicate with the CN 135.
  • the communication network 100A may include any suitable number of network devices and/or terminal devices and/or cells and/or CUs and/or DUs adapted for implementing implementations of the present disclosure.
  • the communications in the communication network 100A may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , New Radio (NR) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , GSM EDGE Radio Access Network (GERAN) , Machine Type Communication (MTC) and the like.
  • GSM Global System for Mobile Communications
  • LTE Long Term Evolution
  • LTE-Evolution LTE-Advanced
  • NR New Radio
  • WCDMA Wideband Code Division Multiple Access
  • CDMA Code Division Multiple Access
  • GERAN GSM EDGE Radio Access Network
  • MTC Machine Type Communication
  • Examples of the communication protocols include, 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, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.
  • uplink (UL) communication Communication in a direction from the terminal device 110 towards the network device 120 is referred to as uplink (UL) communication, while communication in a reverse direction from the network device 120 towards the terminal device 110 is referred to as downlink (DL) communication.
  • the terminal device 110 may move amongst the cells of the network devices 120 and 130 and possibly other network devices.
  • UL communication the terminal device 110 may transmit UL data and control information to the network device 120 or 130 via a UL channel.
  • DL communication the network device 120 or 130 may transmit DL data and control information to the terminal device 110 via a DL channel.
  • the communications in the communication network 100A can be performed in accordance with UP and CP protocol stacks.
  • a communication device such as a terminal device or a network device
  • there are a plurality of entities for a plurality of network protocol layers in a protocol stack which can be configured to implement corresponding processing on data or signaling transmitted from the communication device and received by the communication device.
  • FIG. 1B illustrates a schematic diagram 100B illustrating network protocol layer entities that may be established for UP protocol stack at devices according to some embodiments of the present disclosure. For convenience, the following description is given by taking the network device 120 as an example of a network device.
  • each of the terminal device 110 and the network device 120 may comprise an entity for the L1 layer, i.e., an entity for a physical (PHY) layer (also referred to as a PHY entity) , and one or more entities for upper layers (L2 and layer 3 (L3) layers, or upper layers) including an entity for a MAC layer (also referred to as a MAC entity) , an entity for a radio link control (RLC) layer (also referred to as a RLC entity) , an entity for a packet data convergence protocol (PDCP) layer (also referred to as a PDCP entity) , and an entity for a service data application protocol (SDAP) layer (also referred to as a SDAP entity, which is established in 5G and higher-generation networks) .
  • PHY physical
  • L3 layer 3
  • FIG. 1C illustrates a schematic diagram 100C illustrating network protocol layer entities that may be established for CP protocol stack at devices according to some embodiments of the present disclosure.
  • the network device 120 For convenience, the following description is given by taking the network device 120 as an example of a network device.
  • each of the terminal device 110 and the network device 120 may comprise an entity for the L1 layer, i.e., an entity for a PHY layer (also referred to as a PHY entity) , and one or more entities for upper layers (L2 and L3 layers) including an entity for a MAC layer (also referred to as a MAC entity) , an entity for a RLC layer (also referred to as a RLC entity) , an entity for a PDCP layer (also referred to as a PDCP entity) , and an entity for an RRC layer (also referred to as an RRC entity) .
  • an entity for the L1 layer i.e., an entity for a PHY layer (also referred to as a PHY entity)
  • one or more entities for upper layers including an entity for a MAC layer (also referred to as a MAC entity) , an entity for a RLC layer (also referred to as a RLC entity) , an entity for a PDCP layer (
  • the RRC layer may be also referred to as an access stratum (AS) layer, and thus the RRC entity may be also referred to as an AS entity.
  • the terminal device 110 may also comprise an entity for a non-access stratum (NAS) layer (also referred to as a NAS entity) .
  • NAS non-access stratum
  • An NAS layer at the network side is not located in a network device and is located in CN.
  • L1 refers to the PHY layer
  • L2 refers to the MAC or RLC or PDCP or SDAP layer
  • L3 refers to the RRC layer.
  • L1 or L2 may also be collectively referred to as a lower-layer
  • L3 may also be referred to as a higher-layer
  • L1 or L2 signaling may be also referred to as a lower-layer signaling
  • L3 signaling may be also referred to as a higher-layer signaling.
  • a CU e.g., the CU 121 may be responsible for accomplishing functionalities of RRC, SDAP and PDCP entities, and a DU (e.g., the DU 122 or 123 may be responsible for accomplishing functionalities of the RLC entity, the MAC entity and the PHY entity.
  • a CU and a DU may be implemented in separate devices.
  • a CU and a DU may be implemented in the same device.
  • different DUs may be implemented in separate devices.
  • different CUs are implemented in separate devices.
  • a CU (also referred to as a gNB-CU herein) is a logic node hosting RRC, SDAP and PDCP protocols of a gNB or RRC and PDCP protocols of an en-gNB that controls operation of one or more DUs (also referred to as gNB-DUs herein) .
  • the gNB-CU terminates a F1 interface connected with the gNB-DU.
  • a DU is a logical node hosting RLC, MAC and PHY layers of the gNB or en-gNB, and its operation is partly controlled by gNB-CU.
  • One gNB-DU supports one or multiple cells. One cell is supported by only one gNB-DU.
  • the gNB-DU terminates a F1 interface connected with the gNB-CU.
  • the terminal device 110 may be located within the coverage of the cell 123-1, and the terminal device 110 may communicate with the DU 123 of the network device 120 based on a network configuration.
  • the cell 123-1 may be referred to as a serving cell of the terminal device 110.
  • Other cells such as the cells 122-1, 122-2 and 123-2 may be referred to as candidate cells of the terminal device 110.
  • the terminal device 110 may establish a dual connection (i.e., simultaneous connection) with the network device 120 and the network device 130.
  • the network device 120 may serve as a master node (MN) .
  • the terminal device 110 may communicate with the network device 120 via a set of serving cells.
  • the set of serving cells form an MCG, and a primary cell in the MCG is called as PCell.
  • the PCell may be changed from the cell 123-1 to the cell 131. This is called as a handover (HO) .
  • the network device 120 may serve as a secondary node (SN) .
  • the set of serving cells provided by the network device 120 form an SCG, and a primary cell in the SCG is called as PSCell.
  • the PSCell may be changed from the cell 123-1 to the cell 131. This is called as a PSCell change.
  • the network device 120 may receive L1 measurement reports from the terminal device 110. Based on the L1 measurement reports, the network device 120 may change a serving cell of the terminal device 110 through a MAC CE. This procedure is called as LTM. The network device 120 may prepare one or multiple candidate cells and provides candidate cell configurations to the terminal device 110 through an RRC message. Then an LTM cell switch is triggered by selecting one of the candidate cell configurations as a target configuration for the LTM by the network device 120.
  • FIG. 1D illustrates a signaling chart illustrating an example process 100D of conditional LTM in which some embodiments of the present disclosure can be implemented.
  • the process 100D will be described with reference to FIG. 1A.
  • the process 100D may involve the terminal device 110 and the network device 120 as illustrated in FIG. 1A.
  • the terminal device 110 in a connected state may send 140 a measurement report message to the network device 120.
  • the network device 120 may decide 141 to use LTM and initiate LTM candidate preparation.
  • the network device 120 may transmit 142 an RRC reconfiguration message to the terminal device 110 comprising a configuration (also referred to as an LTM configuration or an LTM candidate configuration herein) of one or multiple LTM candidate target cells.
  • the terminal device 110 may store the configuration of LTM candidate target cell (s) and transmit 143 a RRC reconfiguration complete message to the network device 120.
  • the terminal device 110 may perform 144 downlink (DL) synchronization with candidate cell (s) before receiving s cell switch command.
  • the terminal device 110 may perform 145 early TA acquisition with candidate cell (s) requested by the network device 120 before receiving the cell switch command (i.e., perform uplink (UL) synchronization with candidate cell (s) ) .
  • This may be done via contention free random access (CFRA) triggered by a PDCCH order from a source cell, following which the terminal device 110 sends a preamble towards the indicated candidate cell.
  • CFRA contention free random access
  • the terminal device 110 does not receive a random access response (RAR) for the purpose of TA value acquisition and the TA value of the candidate cell is indicated in the cell switch command.
  • RAR random access response
  • the terminal device 110 does not maintain a TA timer for the candidate cell and relies on network implementation to guarantee TA validity.
  • the terminal device 110 may perform 146 L1 measurements on the configured LTM candidate target cell (s) .
  • the L1 measurements may be performed as long as the RRC reconfiguration is applied in step 142. If a condition is fulfilled at the terminal device 110, the terminal device 110 may execute 147 an LTM cell switch to a target cell.
  • the terminal device 110 may perform 148 an RA procedure towards the target cell if the terminal device 110 does not have valid TA of the target cell.
  • the terminal device 110 may complete 149 the LTM cell switch procedure by sending an RRC reconfiguration complete message to the target cell. If the terminal device 110 has performed the RA procedure in step 148, the terminal device 110 may consider that LTM execution is successfully completed when the RA procedure is successfully completed. For RACH-less LTM, the terminal device 110 may consider that LTM execution is successfully completed when the terminal device 110 determines that the network device 120 has successfully received the first UL data from the terminal device 110.
  • Steps 144 to 149 can be performed multiple times for subsequent LTM cell switch using the LTM candidate cell configuration (s) provided in the step 142.
  • FIG. 1E illustrates a signaling chart illustrating an example process 100E of LTM candidate preparation for an intra-DU scenario in which some embodiments of the present disclosure can be implemented.
  • the process 100E will be described with reference to FIG. 1A.
  • the process 100E may involve the terminal device 110, the CU 121 and the DU 123 as illustrated in FIG. 1A.
  • a source cell and a target candidate cell belong to the same DU.
  • the source cell is the cell 123-1 and the target candidate cell is the cell 123-2.
  • the terminal device 110 may transmit 160, to the DU 123, a measurement report message (i.e., an L3 measurement result) including measurements of neighboring cells.
  • the DU 123 may transmit 161, to the CU 121, a UL RRC MESSAGE TRANSFER message conveying the received measurement report message.
  • the CU 121 may make 162 a decision of LTM configuration, i.e., determine to initiate LTM configuration.
  • the CU 121 may transmit 163, to the DU 123, a UE CONTEXT MODIFICATION REQUEST message including one target candidate cell ID.
  • the CU 121 may request PRACH resources from the DU 123.
  • the DU 123 may respond 164 with a UE CONTEXT MODIFICATION RESPONSE message including generated lower layer RRC configurations (e.g., a transmission configuration indication (TCI) state configuration and a RACH configuration) and a reference signal configuration for an accepted target candidate cell.
  • the CU 121 may transmit 165, to the DU 123, a DL RRC MESSAGE TRANSFER message which includes a generated RRC reconfiguration message with the LTM configuration.
  • FIG. 1F illustrates a signaling chart illustrating an example process 100F of LTM candidate preparation for an inter-DU scenario in which some embodiments of the present disclosure can be implemented.
  • the process 100F may involve the terminal device 110, the CU 121 and the DUs 122 and 123 as illustrated in FIG. 1A.
  • a source cell and a target candidate cell belong to different DUs under the same CU.
  • the source cell is the cell 123-1 and the target candidate cell is the cell 122-1. That is, the DU 123 is a source DU and the DU 122 is a candidate DU.
  • the terminal device 110 may transmit 170, to the DU 123, a measurement report message (i.e., an L3 measurement result) including measurements of neighboring cells.
  • the DU 123 may transmit 171, to the CU 121, a UL RRC MESSAGE TRANSFER message conveying the received measurement report message.
  • the CU 121 may make 172 a decision of LTM configuration, i.e., determine to initiate LTM configuration.
  • the CU 121 may transmit 173, to the DU 122, a UE CONTEXT SETUP REQUEST message including one target candidate cell ID.
  • the CU 121 may indicate an ID of a source DU, and request PRACH resources from the DU 122. If the DU 122 accepts the request of LTM configuration, the DU 122 may respond 174 with a UE CONTEXT SETUP RESPONSE message including generated lower layer RRC configurations (e.g., a transmission configuration indication (TCI) state configuration and a RACH configuration) and a reference signal configuration for an accepted target candidate cell.
  • TCI transmission configuration indication
  • the CU 121 may transmit 175, to the DU 123, a UE CONTEXT MODIFICATION REQUEST message including a collected RS configuration, TCI state configuration and RACH configuration for the accepted target candidate cell (s) in other DUs.
  • the DU 123 may respond 176 with a UE CONTEXT MODIFICATION RESPONSE message which may include the RS configuration of the source cell, prepared candidate cells and a generated CSI resource configuration.
  • the CU 121 transmits 177, to the DU 122, a UE CONTEXT MODIFICATION REQUEST message including the cell ID (s) of the prepared candidate cell (s) and associated RS configuration for each candidate cell in other candidate DU (s) .
  • the candidate cell may be the same cell as the source cell.
  • the DU 122 may respond 178 with a UE CONTEXT MODIFICATION RESPONSE message including a generated CSI resource configuration.
  • the CU 121 may transmit 179, to the DU 123, a DL RRC MESSAGE TRANSFER message which includes a generated RRC reconfiguration message with the LTM configuration.
  • Embodiments of the present disclosure provide solutions of communication for conditional LTM so as to enhance implementation of the conditional LTM. More details will be described with reference to FIGs. 2 to 3 below.
  • LTM cell switch For conventional LTM cell switch, execution of LTM cell switch is triggered by reception of an MAC CE indicating an LTM cell switch command. TCI state information is included in the LTM dell switch command such that a terminal device performs transmission and reception on a target LTM cell based on the TCI state information indicated.
  • the MAC CE indicating the LTM cell switch command is not sent to the terminal device. Thus, it is unclear how to trigger execution of LTM cell switch and how to perform transmission and reception on the target LTM cell in the case of conditional LTM cell switch.
  • embodiments of the present disclosure provide a solution of triggering and executing a conditional LTM cell switch.
  • the solution will be described in connection with FIG. 2 below.
  • FIG. 2 illustrates a signaling chart illustrating an example process 200 of communication for conditional LTM according to embodiments of the present disclosure.
  • the process 200 may involve the terminal device 110 and the network device 120 as illustrated in FIG. 1A.
  • the network device 120 provides a serving cell for the terminal device 110 and also provides one or more candidate cells for the terminal device 110.
  • the serving cell may be SpCell, PCell or PSCell of the terminal device 110.
  • the terminal device 110 may determine 210 whether a L1 measurement result for at least one beam or RS in a list of beams or RSs associated with a candidate cell allowing LTM fulfills a condition (for convenience, also referred to as a first condition herein) .
  • the beam or RS may be a synchronization signal block (SSB) .
  • the beam or RS may be a channel status information reference signal (CSI-RS) . It is to be understood that the beam or RS may adopt any other suitable forms, and the present disclosure does not limit this aspect.
  • the network device 120 may transmit a list of LTM configurations of one or more candidate cells allowing LTM.
  • Each LTM configuration in the list of LTM configurations is associated with one candidate cell and includes the configuration of the execution condition for LTM cell switch to the one candidate cell.
  • the configuration of the execution condition may comprise information of the first condition associated with the candidate cell.
  • the information of the first condition may comprise a threshold (for convenience, also referred to as a first threshold herein) for comparison with the L1 measurement result for the at least one beam or RS associated with the candidate cell.
  • the information of the first condition may comprise a threshold (for convenience, also referred to as a second threshold herein) for comparison with a measurement result (e.g., L1 or L3 measurement result) associated with the serving cell.
  • the information of the first condition may comprise an offset for a L1 measurement result for at least one beam or RS associated with the serving cell.
  • the information of the first condition may comprise a time window (e.g., a length of the time window) for determination of the L1 measurement result for the at least one beam or RS associated with the candidate cell. It is to be understood that any combination of the above information of the first condition may also be feasible.
  • the configuration of the execution condition may comprise the list of beams or RSs associated with the candidate cell for L1 measurement. It is to be understood that the configuration of the execution condition may comprise any other suitable information or any combination of information.
  • the terminal device 110 may store 212 the configuration of the execution condition in a UE variable, and perform conditional LTM evaluation.
  • the terminal device 110 may perform the L1 measurement for each beam or RS in the list of beams or RSs. With the L1 measurement, the terminal device 110 may determine whether the L1 measurement result for the at least one beam or RS in the list fulfills the first condition. In some embodiments, during the conditional LTM evaluation, the terminal device 110 may also perform measurement for the serving cell to determine if the fist condition is fulfilled. In some embodiments, measurement for the serving cell is an L3 measurement. In some embodiments, the measurement for the serving cells is an L1 measurement for at least one beam or RS associated with the serving cell.
  • the terminal device 110 may determine, as the L1 measurement result, an averaged value of a set of L1 instantaneous measurement results within the time window. As such, an accurate L1 measurement result may be obtained and an LTM cell switch may be triggered suitably.
  • the L1 measurement result may include reference signal received power (RSRP) of the beam or RS. In some embodiments, the L1 measurement result may include reference signal received quality (RSRQ) of the beam or RS. In some embodiments, the L1 measurement result may include signal to interference plus noise ratio (SINR) of the beam or RS. It is to be understood that any other suitable measurement metrics may also be feasible.
  • RSRP reference signal received power
  • RSRQ reference signal received quality
  • SINR signal to interference plus noise ratio
  • the first condition may comprise that the L1 measurement result for the at least one beam or RS associated with the candidate cell is above the first threshold. In some embodiments, the first condition may comprise that the L1 measurement result for the at least one beam or RS associated with the candidate cell is above the first threshold and a measurement result (e.g., L1 or L3 measurement result) associated with a serving cell is below the second threshold. In other words, when the measurement result associated with the serving cell is below the second threshold, the L1 measurement result for at least one beam or RS associated with the candidate cell is above the first threshold.
  • the measurement result associated with the serving cell is a physical layer measurement result for at least one beam or RS associated with the serving cell. In some embodiments, the beam or RS associated with the serving cell is a beam with the highest L1 measurement result, e.g., a beam with the highest RSRP or RSRQ value.
  • the first condition may comprise that the L1 measurement result for the at least one beam or RS associated with the candidate cell is above an L1 measurement result for at least one beam or RS associated with the serving cell. In some embodiments, the first condition may comprise that the L1 measurement result for the at least one beam or RS associated with the candidate cell is above the L1 measurement result for the at least one beam or RS associated with the serving cell plus the offset. In some embodiments, the beam or RS associated with the serving cell is a beam with the highest L1 measurement result, e.g., a beam with the highest RSRP or RSRQ value.
  • the first condition may comprise any other suitable conditions or any combination of conditions.
  • the terminal device 110 may determine 220 that an execution condition for a cell switch to the candidate cell is not fulfilled.
  • the terminal device 110 may determine 230 that the execution condition for the cell switch to the candidate cell is fulfilled. In other words, for one of LTM candidate cells, if an L1 measurement result of at least one beam or RS associated with the LTM candidate cell fulfills the condition configured, the terminal device 110 may consider an execution condition for the LTM candidate cell/configuration as fulfilled, and decide to perform an LTM cell switch execution to the LTM candidate cell.
  • the terminal device 110 may perform 240 the cell switch to the candidate cell if the execution condition for the cell switch to the candidate cell is fulfilled.
  • the terminal device 110 may select 241 a beam or RS (for convenience, also referred to as a first beam or RS herein) from the at least one beam or RS fulfilling the first condition.
  • the at least one beam or RS may comprise only a single beam or RS (i.e., the first beam or RS) .
  • the terminal device 110 may consider the single beam or RS which L1 measurement result fulfills the first condition as the selected beam or RS.
  • the at least one beam or RS may comprise multiple beams or RSs.
  • the terminal device 110 may select one of the multiple beams or RSs based on L1 measurement results of the multiple beams or RSs. For example, the terminal device 110 may select a beam or RS with a better measurement result (e.g., higher RSRP or RSRQ) in the multiple beams or RSs. It is to be understood that any other suitable ways of selection are also feasible, and the present disclosure does not limit this aspect.
  • the terminal device 110 may perform 242 UL transmission or DL reception towards the candidate cell.
  • the terminal device 110 may apply a configured grant (e.g., configured UL grant) associated with the selected beam or RS for an initial UL transmission or retransmission of the initial UL transmission.
  • a configured grant e.g., configured UL grant
  • the terminal device 110 may consider the configured grant as valid. Otherwise, the terminal device 110 may consider the configured grant as invalid.
  • the terminal device 110 may apply the selected beam or RS during an RA procedure for the cell switch. In some embodiments for a contention based random access (CBRA) procedure, the terminal device 110 may select the selected beam or RS during an RA resource selection procedure. In some embodiments, the terminal device 110 may continue assuming that the DM-RS antenna port associated with transmission (e.g., PUCCH or PUSCH transmission) or receptions (e.g., PDCCH or PDSCH reception) is quasi co-located with the selected beam or RS if no MAC CE activation command indicating a TCI state is received after the RA procedure.
  • transmission e.g., PUCCH or PUSCH transmission
  • receptions e.g., PDCCH or PDSCH reception
  • the terminal device 110 may use the selected beam or RS to select a CFRA resource for an RA procedure of LTM.
  • CFRA resources are configured for the LTM candidate cell
  • the terminal device 110 may select an RA resource which is associated with the selected beam or RS.
  • a beam or RS associated with the RA resource may have the same index as the selected beam or RS.
  • the terminal device 110 may apply the selected beam or RS for the UL transmission or DL reception after completion of the RA procedure for the cell switch.
  • the terminal device 110 may assume that an antenna port for the UL transmission (e.g., PUCCH or PUSCH transmission) or DL reception (e.g., PDCCH or PDSCH reception) is quasi co-located with the selected beam or RS.
  • the terminal device 110 may assume that a demodulation reference signal (DM-RS) antenna port for PDCCH receptions is quasi co-located with the selected beam or RS.
  • DM-RS demodulation reference signal
  • conditional LTM cell switch may be triggered and executed.
  • a terminal device may monitor PDCCH for dynamic scheduling from a target cell for initial UL transmission upon LTM cell switch. Since TCI state information is indicated in an LTM cell switch command MAC CE, the terminal device may perform PDCCH monitoring based on the TCI state indicated. However, in case of conditional LTM, there is no LTM cell switch command MAC CE, and thus no TCI state information is indicated. In this case, it is unclear how to perform RACH-less conditional LTM.
  • embodiments of the present disclosure also provide solutions of performing RACH-less conditional LTM.
  • the solutions will be described in connection with Embodiments 1 and 2 below.
  • a PDCCH for a dynamic grant (e.g., dynamic UL grant, UL grant addressed to a cell-radio network temporary identifier (C-RNTI) of the terminal device 110) of initial UL transmission are transmitted in all transmitted beams.
  • a dynamic grant e.g., dynamic UL grant, UL grant addressed to a cell-radio network temporary identifier (C-RNTI) of the terminal device 110
  • C-RNTI cell-radio network temporary identifier
  • the terminal device 110 may determine 251 a beam (for convenience, also referred to as a second beam herein) for reception of a dynamic grant of an initial UL transmission.
  • the terminal device 110 may select one beam for reception of a PDCCH for the dynamic grant based on UE implementation.
  • the terminal device 110 may use the selected beam as that in step 241 for the reception of the PDCCH for the dynamic grant.
  • the second beam may be an SSB or any other suitable forms.
  • the terminal device 110 may determine 252 a set of occasions for a PDCCH monitoring for the dynamic grant based on the second beam and a configuration of a search space.
  • PDCCH monitoring occasion (s) may be determined according to a search space configured.
  • the configuration of the search space may be included in an LTM configuration associated with the candidate cell.
  • the terminal device 110 may determine the set of occasions corresponding to the second beam based on a fixed (or unconfigurable) mapping between PDCCH monitoring occasions and beams. For example, If the ID of the search space is set to zero, the terminal device 110 may perform PDCCH monitoring for dynamic grant of initial UL transmission based on a fixed (or unconfigurable) mapping between PDCCH monitoring occasions and SSBs.
  • the terminal device 110 may determine the set of occasions corresponding to the second beam based on an index of the second beam, a configured number of occasions in the set of occasions, and a configured number of actual transmitted beams.
  • X and N are configured.
  • X denotes the configured number of occasions in the set of occasions, and N denotes the configured number of actual transmitted SSBs.
  • the terminal device 110 may determine the set of occasions corresponding to the second beam based on an index of the second beam. For example, the Kth PDCCH monitoring occasion corresponds to the Kth transmitted SSB.
  • a mapping between PDCCH monitoring occasions and beams may be based on a configuration (i.e., configurable) .
  • the terminal device 110 may perform PDCCH monitoring for dynamic grant of initial UL transmission based on the configurable mapping.
  • the terminal device 110 may not be required to monitor subsequent PDCCH (e.g., associated with the beam selected for PDCCH monitoring) if the terminal device 110 had detected PDCCH.
  • the terminal device 110 may determine 253 the dynamic grant for the initial UL transmission by performing the PDCCH monitoring on the set of occasions. In this way, the terminal device 110 may perform the initial UL transmission towards the candidate cell by using the dynamic grant in case of RACH-less conditional LTM.
  • the terminal device 110 may perform 260 UL transmission or DL reception towards the candidate cell by skipping an RA procedure or using RA procedure.
  • the terminal device 110 may skip 261 an RA procedure for the LTM cell switch. If the configured grant for the LTM cell switch is not configured, the terminal device 110 may perform 262 the RA procedure for the LTM cell switch. In other words, for the candidate cell (i.e., a target LTM cell) , only if a configured grant for LTM is configured, an RA procedure may be skipped for LTM. Otherwise, the terminal device 110 may determine that the RA procedure is not skipped for LTM cell switch, i.e., the terminal device 110 may perform the RA procedure during the LTM cell switch.
  • the candidate cell i.e., a target LTM cell
  • a terminal device may use a configured grant for RACH-less conditional LTM. So far, a RACH-less conditional LTM cell switch is described.
  • an execution condition for LTM is generated by a CU because the execution condition is based on event triggered L3 measurement.
  • the execution condition is based on L1 measurement.
  • embodiments of the present disclosure provide a solution for generating a configuration of an execution condition for LTM cell switch.
  • the solution will be described below in connection with FIG. 3.
  • FIG. 3 illustrates a signaling chart illustrating another example process 300 of communication for conditional LTM according to embodiments of the present disclosure.
  • the process 300 may involve the CU 121 and one of DUs (e.g., the DU 122 or 123) of the network device 120 as illustrated in FIG. 1A.
  • the network device 120 provides a serving cell for the terminal device 110 and also provides one or more candidate cells for the terminal device 110.
  • the serving cell may be SpCell, PCell or PSCell of the terminal device 110.
  • the CU 121 makes a decision of conditional LTM configuration, i.e., determine to initiate conditional LTM configuration.
  • the CU 121 may transmit 310, to the DU 122 or 123, LTM information associated with a candidate cell allowing LTM.
  • the LTM information comprises an indication that a cell switch to the candidate cell is conditional.
  • the LTM information may also be referred to as information of the cell switch to the candidate cell.
  • the CU 121 may transmit the LTM information associated with the candidate cell via an F1 message.
  • the F1 message may be a UE CONTEXT SETUP REQUEST message in case the DU 122 or 123 is a serving DU or a source DU.
  • the F1 message may be a UE CONTEXT MODIFICATION REQUEST message in case the DU 122 or 123 is a candidate DU. It is to be understood that any other suitable messages may also be feasible.
  • the DU 122 or 123 may transmit 320, to the CU 121, a configuration of an execution condition for the cell switch to the candidate cell. That is, the configuration of the execution condition for the candidate cell may be generated by the DU 122 or 123.
  • the DU 122 or 123 may transmit the configuration of the execution condition via an F1 message.
  • the F1 message may be a UE CONTEXT SETUP RESPONSE message in case the DU 122 or 123 is a serving DU or a source DU.
  • the F1 message may be a UE CONTEXT MODIFICATION RESPONSE message in case the DU 122 or 123 is a candidate DU. It is to be understood that any other suitable messages may also be feasible.
  • the configuration of the execution condition may comprise at least one of the following: information of a first condition associated with the candidate cell; or a list of beams or RSs associated with the candidate cell.
  • the information of the first condition may comprise at least one of the following: a first threshold for comparison with an L1 measurement result for at least one beam or RS associated with the candidate cell; a second threshold for comparison with a measurement result associated with a serving cell; an offset for an L1 measurement result for at least one beam or reference signal associated with the serving cell; or a time window for determination of the L1 measurement result for the at least one beam or RS associated with the candidate cell.
  • the first condition may comprise at least one of the following: an L1 measurement result for at least one beam or RS associated with the candidate cell is above the first threshold; the L1 measurement result for the at least one beam or RS associated with the candidate cell is above the first threshold and a measurement result associated with a serving cell is below the second threshold; the L1 measurement result for the at least one beam or reference signal associated with the candidate cell is above an L1 measurement result for at least one beam or RS associated with the serving cell; or the L1 measurement result for the at least one beam or reference signal associated with the candidate cell is above the L1 measurement result for the at least one beam or RS associated with the serving cell plus an offset.
  • the L1 measurement result for the at least one beam or reference signal associated with the candidate cell may be an averaged value of a set of layer 1 instantaneous measurement results within the time window.
  • a configuration of an execution condition for LTM may be generated by a DU.
  • operations of the process 200 may be carried out separately or in any suitable combination with operations 100D, and that operations of the process 300 may be carried out separately or in any suitable combination with operations of the process 100E or 100F.
  • embodiments of the present disclosure provide methods of communication implemented at a terminal device and at a DU and a CU of a network device. These methods will be described below with reference to FIGs. 4 to 6.
  • FIG. 4 illustrates a flowchart of an example method 400 of communication implemented at a terminal device in accordance with some embodiments of the present disclosure.
  • the method 400 may be performed at the terminal device 110 as shown in FIG. 1A.
  • the method 400 will be described with reference to FIG. 1A. It is to be understood that the method 400 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.
  • the terminal device 110 determines that an L1 measurement result for at least one beam or RS in a list of beams or RSs associated with a candidate cell allowing LTM fulfills a first condition.
  • the first condition may comprise at least one of the following: an L1 measurement result for at least one beam or RS associated with the candidate cell is above a first threshold; the L1 measurement result for the at least one beam or RS associated with the candidate cell is above the first threshold and a measurement result associated with a serving cell is below a second threshold; the L1 measurement result for the at least one beam or reference signal associated with the candidate cell is above an L1 measurement result for at least one beam or RS associated with the serving cell; or the L1 measurement result for the at least one beam or reference signal associated with the candidate cell is above the L1 measurement result for the at least one beam or RS associated with the serving cell plus an offset.
  • the terminal device 110 may determine, as the L1 measurement result, an averaged value of a set of L1 instantaneous measurement results within a time window.
  • the terminal device 110 may receive, from a network device (e.g., the network device 120) , a configuration of the execution condition.
  • the configuration of the execution condition may comprise at least one of the following: information of the first condition associated with the candidate cell; or the list of beams or reference signals associated with the candidate cell.
  • the information of the first condition may comprise at least one of the following: the first threshold for comparison with an L1 measurement result for at least one beam or RS associated with the candidate cell; the second threshold for comparison with a measurement result associated with a serving cell; the offset for an L1 measurement result for at least one beam or reference signal associated with the serving cell; or the time window for determination of the L1 measurement result for the at least one beam or RS associated with the candidate cell.
  • the terminal device 110 determines that an execution condition for a cell switch to the candidate cell is fulfilled.
  • the terminal device 110 performs the cell switch to the candidate cell.
  • the terminal device 110 may select a first beam or RS from the at least one beam or RS, and perform, based on the first beam or RS, UL transmission or DL reception towards the candidate cell.
  • the terminal device 110 may perform the UL transmission or DL reception by: applying a configured grant associated with the first beam or RS for an initial UL transmission or retransmission of the initial UL transmission; applying the first beam or RS during an RA procedure for the cell switch; or applying the first beam or RS for the UL transmission or DL reception after completion of the RA procedure.
  • the terminal device 110 may perform the cell switch by determining a second beam for reception of a dynamic grant of an initial UL transmission; determining, based on the second beam and a configuration of a search space, a set of occasions for a PDCCH monitoring for the dynamic grant; and determining the dynamic grant for the initial UL transmission by performing the PDCCH monitoring on the set of occasions.
  • the terminal device 110 may determine, based on a fixed mapping between PDCCH monitoring occasions and beams, the set of occasions corresponding to the second beam. In some embodiments, if the ID of the search space is not set to zero, the terminal device 110 may determine the set of occasions corresponding to the second beam based on an index of the second beam, a configured number of occasions in the set of occasions, and a configured number of actual transmitted beams. In some embodiments, if the ID of the search space is not set to zero, the terminal device 110 may determine the set of occasions corresponding to the second beam based on the index of the second beam.
  • the terminal device 110 may skip an RA procedure for the cell switch. In some embodiments, if no configured grant for the cell switch is configured, the terminal device 110 may perform the RA procedure for the cell switch.
  • the terminal device 110 may determine that the execution condition for the cell switch to the candidate cell is unfulfilled.
  • a conditional LTM cell switch may be triggered and executed. Further, an RACH-less conditional LTM cell switch may be triggered and executed.
  • FIG. 5 illustrates a flowchart of an example method 500 of communication implemented at a DU of a network device in accordance with some embodiments of the present disclosure.
  • the method 500 may be performed at the DU 122 or 123 as shown in FIG. 1A.
  • the method 500 will be described with reference to FIG. 1A. It is to be understood that the method 500 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.
  • the DU 122 or 123 receives, from the CU 121 of the network device 120, information of a cell switch to a candidate cell allowing LTM.
  • the information of the cell switch comprises an indication that the cell switch to the candidate cell is conditional.
  • the DU 122 or 123 transmits, to the CU 121, a configuration of an execution condition for the cell switch to the candidate cell.
  • the configuration of the execution condition may comprise at least one of the following: information of a first condition associated with the candidate cell; or a list of beams or RSs associated with the candidate cell.
  • the information of the first condition may comprise at least one of the following: a first threshold for comparison with an L1 measurement result for at least one beam or RS associated with the candidate cell; a second threshold for comparison with a measurement result associated with a serving cell; an offset for an L1 measurement result for at least one beam or reference signal associated with the serving cell; or a time window for determination of the L1 measurement result for the at least one beam or RS associated with the candidate cell.
  • the first condition may comprise at least one of the following: an L1 measurement result for at least one beam or RS associated with the candidate cell is above the first threshold; the L1 measurement result for the at least one beam or RS associated with the candidate cell is above the first threshold and a measurement result associated with a serving cell is below the second threshold; the L1 measurement result for the at least one beam or reference signal associated with the candidate cell is above an L1 measurement result for at least one beam or RS associated with the serving cell; or the L1 measurement result for the at least one beam or reference signal associated with the candidate cell is above the L1 measurement result for the at least one beam or RS associated with the serving cell plus an offset.
  • the L1 measurement result for the at least one beam or reference signal associated with the candidate cell may be an averaged value of a set of layer 1 instantaneous measurement results within the time window.
  • a configuration of execution condition for LTM may be generated by a DU and transmitted to a CU.
  • FIG. 6 illustrates a flowchart of an example method 600 of communication implemented at a CU of a network device in accordance with some embodiments of the present disclosure.
  • the method 600 may be performed at the CU 121 as shown in FIG. 1A.
  • the method 600 will be described with reference to FIG. 1A. It is to be understood that the method 600 may include additional blocks not shown and/or may omit some blocks as shown, and the scope of the present disclosure is not limited in this regard.
  • the CU 121 transmit, to the DU 122 or 123 of the network device 120, information of a cell switch to a candidate cell allowing LTM.
  • the information of the cell switch comprises an indication that the cell switch to the candidate cell is conditional.
  • the CU 121 receives, from the DU 122 or 123, a configuration of an execution condition for the cell switch to the candidate cell.
  • the configuration of the execution condition may comprise at least one of the following: information of a first condition associated with the candidate cell; or a list of beams or RSs associated with the candidate cell.
  • the information of the first condition may comprise at least one of the following: a first threshold for comparison with an L1 measurement result for at least one beam or RS associated with the candidate cell; a second threshold for comparison with a measurement result associated with a serving cell; an offset for an L1 measurement result for at least one beam or reference signal associated with the serving cell; or a time window for determination of the L1 measurement result for the at least one beam or RS associated with the candidate cell.
  • the first condition may comprise at least one of the following: an L1 measurement result for at least one beam or RS associated with the candidate cell is above the first threshold; the L1 measurement result for the at least one beam or RS associated with the candidate cell is above the first threshold and a measurement result associated with a serving cell is below the second threshold; the L1 measurement result for the at least one beam or reference signal associated with the candidate cell is above an L1 measurement result for at least one beam or RS associated with the serving cell; or the L1 measurement result for the at least one beam or reference signal associated with the candidate cell is above the L1 measurement result for the at least one beam or RS associated with the serving cell plus an offset.
  • the L1 measurement result for the at least one beam or reference signal associated with the candidate cell may be an averaged value of a set of layer 1 instantaneous measurement results within the time window.
  • a CU may receive a configuration of execution condition for LTM from a DU.
  • FIG. 7 is a simplified block diagram of a device 700 that is suitable for implementing embodiments of the present disclosure.
  • the device 700 can be considered as a further example implementation of the terminal device 110 or a DU or CU of the network device 120 as shown in FIG. 1A. Accordingly, the device 700 can be implemented at or as at least a part of the terminal device 110 or a DU or CU of the network device 120.
  • the device 700 includes a processor 710, a memory 720 coupled to the processor 710, a suitable transceiver 740 coupled to the processor 710, and a communication interface coupled to the transceiver 740.
  • the memory 710 stores at least a part of a program 730.
  • the transceiver 740 may be for bidirectional communications or a unidirectional communication based on requirements.
  • the transceiver 740 may include at least one of a transmitter 742 or a receiver 744.
  • the transmitter 742 and the receiver 744 may be functional modules or physical entities.
  • the transceiver 740 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones.
  • the communication interface may represent any interface that is necessary for communication with other network elements, such as X2/Xn interface for bidirectional communications between eNBs/gNBs, S1/NG interface for communication between a Mobility Management Entity (MME) /Access and Mobility Management Function (AMF) /SGW/UPF and the eNB/gNB, Un interface for communication between the eNB/gNB and a relay node (RN) , or Uu interface for communication between the eNB/gNB and a terminal device.
  • MME Mobility Management Entity
  • AMF Access and Mobility Management Function
  • RN relay node
  • Uu interface for communication between the eNB/gNB and a terminal device.
  • the program 730 is assumed to include program instructions that, when executed by the associated processor 710, enable the device 700 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGs. 1A to 6.
  • the embodiments herein may be implemented by computer software executable by the processor 710 of the device 700, or by hardware, or by a combination of software and hardware.
  • the processor 710 may be configured to implement various embodiments of the present disclosure.
  • a combination of the processor 710 and memory 720 may form processing means 750 adapted to implement various embodiments of the present disclosure.
  • the memory 720 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 720 is shown in the device 700, there may be several physically distinct memory modules in the device 700.
  • the processor 710 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 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.
  • a terminal device comprises a circuitry configured to: in accordance with a determination that an L1 measurement result for at least one beam or reference signal in a list of beams or reference signals associated with a candidate cell allowing LTM fulfills a first condition, determine that an execution condition for a cell switch to the candidate cell is fulfilled; and perform the cell switch to the candidate cell.
  • a DU of a network device comprises a circuitry configured to: receive, from a CU of the network device, information of a cell switch to a candidate cell allowing LTM, the information of the cell switch comprising an indication that the cell switch to the candidate cell is conditional; and transmit, to the CU, a configuration of an execution condition for the cell switch to the candidate cell.
  • a CU of a network device comprises a circuitry configured to: transmit, to a DU of the network device, information of a cell switch to a candidate cell allowing LTM, the information of the cell switch comprising an indication that the cell switch to the candidate cell is conditional; and receive, from the DU, a configuration of an execution condition for the cell switch to the candidate cell.
  • circuitry used herein may refer to hardware circuits and/or combinations of hardware circuits and software.
  • the circuitry may be a combination of analog and/or digital hardware circuits with software/firmware.
  • the circuitry may be any portions of hardware processors with software including digital signal processor (s) , software, and memory (ies) that work together to cause an apparatus, such as a terminal device or a network device, to perform various functions.
  • the circuitry may be hardware circuits and or processors, such as a microprocessor or a portion of a microprocessor, that requires software/firmware for operation, but the software may not be present when it is not needed for operation.
  • the term circuitry also covers an implementation of merely a hardware circuit or processor (s) or a portion of a hardware circuit or processor (s) and its (or their) accompanying software and/or firmware.
  • 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 with reference to FIGs. 1A to 6.
  • 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.

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  • 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 divulgation concernent des dispositifs et des procédés de communication. Selon un aspect, si un résultat de mesurage L1 pour au moins un faisceau ou un RS dans une liste de faisceaux ou de RS associés à une cellule candidate autorisant la LTM remplit une première condition, un dispositif terminal détermine qu'une condition d'exécution d'une commutation de cellule à la cellule candidate est satisfaite et effectue la commutation de cellule à la cellule candidate. De cette manière, une commutation de cellule LTM conditionnelle peut être déclenchée et exécutée.
PCT/CN2023/124796 2023-10-16 2023-10-16 Dispositifs et procédés de communication Pending WO2025081313A1 (fr)

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