Communication method, communication apparatus, and communication system

Abstract

Embodiments of the present application provide a communication method, a communication apparatus, and a communication system. The communication apparatus is applied to a first node. The apparatus comprises a first processing unit that controls the first node to perform the following operations: the first node determines to configure L1 / L2 triggered mobility (LTM); and the first node sends a first message to a second node, the first message comprising first information about the LTM, and the first message being a handover request message or a handover cancel message.

Description

Communication method, communication device and communication system Technical Field

[0001] The embodiments of the present application relate to the field of communication technologies. Background Art

[0002] Network-controlled mobility applies to connected terminals and can be divided into two types of mobility: cell-level mobility and beam-level mobility. Cell-level mobility includes Layer 3 or Layer 1 / 2 mobility.

[0003] Layer 3 based mobility:

[0004] Serving cell changes are triggered by L3 measurements and completed by Radio Resource Control (RRC) signalling, with Reconfiguration with Synchronisation triggered for changes in the Primary Cell (PCell) and Primary Secondary Cell (PSCell), and the release of Secondary Cells (SCells) when applicable. Cell-level mobility is triggered by explicit RRC signalling, i.e. handover. The RRC-triggered handover mechanism requires the terminal device (e.g. User Equipment UE) to at least reset the Medium Access Control (MAC) entity and re-establish the Radio Link Control (RLC). RRC-managed handovers are supported with and without re-establishment of the Packet Data Convergence Protocol (PDCP) entity. For Radio Data Bearers (DRBs) using RLC AM mode, PDCP can either re-establish with security key update or initiate a data recovery procedure without key update. For DRBs using RLC UM mode, PDCP can either re-establish with security key update or remain unchanged without key update. For signaling radio bearers (SRBs), PDCP can remain unchanged without key update, discard stored PDCP packet data units / signaling data units (PDUs / SDUs), or re-establish with security key update.

[0005] Layer 1 / 2 based mobility:

[0006] For RRC-triggered handover mechanisms, all cases involve a complete Layer 2 and Layer 1 (L2 / L1) reset, resulting in higher latency, greater overhead, and longer disruption than beam switching mobility. The goal of L1 / L2 mobility enhancement is to ensure that serving cell changes via L1 / L2 signaling reduce latency, overhead, and disruption.

[0007] Layer 1 / 2 Triggered Mobility (LTM) is a process in which a network device (e.g., a gNB) receives Layer 1 measurement reports from a UE. Based on these reports, the gNB changes the UE's serving cell via a cell change command sent via a Media Access Control Element (MAC CE). The MAC-triggered cell change mechanism (i.e., LTM cell change) requires the UE to at least reset the MAC entity. The RLC handling depends on the network configuration.

[0008] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art.

[0009] Summary of the Invention

[0010] The inventors of this application discovered that current LTM operations only support inter-cell mobility within the same gNB (same CU). When switching from cell 1 of gNB1 to cell 2 of gNB2, a terminal device cannot use LTM and can only use Layer 3 handover (L3 HO), which is a synchronous reconfiguration triggered by an RRC reconfiguration message. This situation significantly limits the opportunities for using LTM.

[0011] In response to at least one of the above problems or other similar problems, embodiments of the present application provide a communication method, a communication device, and a communication system.

[0012] According to one aspect of an embodiment of the present application, a communication device is provided, applied to a first node, the device including a first processing unit, which controls the first node to perform the following operations:

[0013] The first node decides to configure Layer 1 / Layer 2 Triggered Mobility (LTM); and

[0014] The first node sends a first message to the second node, where the first message includes first information about the layer 1 / layer 2 triggered mobility, and the first message is a handover request message or a handover cancel message.

[0015] According to another aspect of an embodiment of the present application, a communication device is provided, applied to a second node, the device including a second processing unit, which controls the second node to perform the following operations:

[0016] The second node receives a first message sent by the first node, where the first message includes first information about the layer 1 / layer 2 triggered mobility, and the first message is a handover request message or a handover cancel message.

[0017] One of the beneficial effects of the embodiments of the present application is that: the use scenarios of LTM are expanded and flexibility is improved; and the proportion of LTM cell changes with smaller latency used in the entire system is increased, thereby improving the system throughput.

[0018] With reference to the following description and accompanying drawings, specific embodiments of the present application are disclosed in detail, indicating the manner in which the principles of the present application can be employed. It should be understood that the embodiments of the present application are not limited in scope. Within the spirit and scope of the appended claims, the embodiments of the present application include many variations, modifications and equivalents.

[0019] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0020] It should be emphasized that the term "include / comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The elements and features described in one figure or one embodiment of the present application can be combined with the elements and features shown in one or more other figures or embodiments. In addition, in the accompanying drawings, similar reference numerals represent corresponding parts in several figures and can be used to indicate corresponding parts used in more than one embodiment.

[0022] FIG1 is a schematic diagram of a communication system of the present application;

[0023] FIG2 is a schematic diagram of contention-free random access (CFRA);

[0024] Figure 3 is a schematic diagram of an inter-cell mobility scenario under the same gNB(-CU);

[0025] FIG4 is a schematic diagram of an inter-CU LTM scenario;

[0026] FIG5 is a schematic diagram of an intra-CU LTM scenario;

[0027] FIG6 is a schematic diagram of a communication method according to an embodiment of the first aspect of the present application;

[0028] FIG7 is a schematic diagram of the transmission process of timing advance (TA) information;

[0029] FIG8 is a schematic diagram of the LTM cell change notification process;

[0030] Figure 9 is a schematic diagram of inter-gNB LTM;

[0031] Figure 10 is a schematic diagram of inter-gNB LTM;

[0032] FIG11 is a schematic diagram of a communication method according to an embodiment of the second aspect;

[0033] FIG12 is a schematic diagram of a communication device according to an embodiment of the third aspect;

[0034] FIG13 is a schematic diagram of a communication device according to an embodiment of the fourth aspect;

[0035] FIG14 is a schematic diagram of an electronic device according to an embodiment of the fifth aspect. DETAILED DESCRIPTION

[0036] The above and other features of the present application will become apparent through the following description with reference to the accompanying drawings. In the description and the accompanying drawings, specific embodiments of the present application are disclosed in detail, which illustrate some embodiments in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described embodiments. On the contrary, the present application includes all modifications, variations and equivalents that fall within the scope of the appended claims.

[0037] In the embodiments of the present application, the terms "first," "second," etc. are used to distinguish different elements in terms of title, but do not indicate the spatial arrangement or temporal order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one and all combinations of one or more of the associated listed terms. The terms "comprising," "including," "having," etc. refer to the presence of the stated features, elements, components, or components, but do not exclude the presence or addition of one or more other features, elements, components, or components.

[0038] In the embodiments of this application, the singular forms "a," "the," etc. include plural forms and should be broadly understood to mean "a" or "a type" rather than being limited to "one." Furthermore, the term "said" should be understood to include both singular and plural forms, unless the context clearly indicates otherwise. Furthermore, the term "according to" should be understood to mean "at least in part based on...", and the term "based on" should be understood to mean "at least in part based on...", unless the context clearly indicates otherwise.

[0039] In the embodiments of the present application, the term "communication network" or "wireless communication network" may refer to a network that complies with any of the following communication standards, such as New Radio (NR), Long Term Evolution (LTE), Enhanced Long Term Evolution (LTE-A, LTE-Advanced), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), etc.

[0040] Furthermore, communication between devices in the communication system may be carried out according to communication protocols of any stage, for example, including but not limited to the following communication protocols: 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G and 5G, New Radio (NR), etc., and / or other communication protocols currently known or to be developed in the future.

[0041] In the embodiments of the present application, the term "network device" refers to, for example, a device in a communication system that connects a terminal device to a communication network and provides services for the terminal device. Network devices may include, but are not limited to, the following devices: an integrated access and backhaul node (IAB-node), a base station (BS), an access point (AP), a transmission reception point (TRP), a broadcast transmitter, a mobile management entity (MME), a gateway, a server, a radio network controller (RNC), a base station controller (BSC), and the like.

[0042] Base stations may include, but are not limited to, NodeB (NB), evolved NodeB (eNodeB or eNB), and 5G base stations (gNB), among others. They may also include remote radio heads (RRHs), remote radio units (RRUs), relays, or low-power nodes (e.g., femeto, pico, etc.). The term "base station" may include some or all of their functions, and each base station may provide communication coverage for a specific geographic area. The term "cell" may refer to a base station and / or its coverage area, depending on the context in which the term is used.

[0043] In the embodiments of the present application, the term "user equipment" (UE) or "terminal equipment" (TE) refers to, for example, a device that accesses a communication network through a network device and receives network services. A terminal device can be fixed or mobile and may also be referred to as a mobile station (MS), a terminal, a subscriber station (SS), an access terminal (AT), a station, etc.

[0044] Among them, terminal devices may include but are not limited to the following devices: cellular phones, personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, machine-type communication devices, laptop computers, cordless phones, smart phones, smart watches, digital cameras, etc.

[0045] For another example, in scenarios such as the Internet of Things (IoT), the terminal device can also be a machine or device for monitoring or measurement, including but not limited to: machine type communication (MTC) terminal, vehicle-mounted communication terminal, device-to-device (D2D) terminal, machine-to-machine (M2M) terminal, and so on.

[0046] In addition, the term "network side" or "network device side" refers to one side of the network, which can be a base station or one or more network devices as mentioned above. The term "user side" or "terminal side" or "terminal device side" refers to the user or terminal side, which can be a UE or one or more terminal devices as mentioned above.

[0047] In the following description, the terms "uplink control signal" and "uplink control information (UCI)" or "physical uplink control channel (PUCCH)" are interchangeable, and the terms "uplink data signal" and "uplink data information" or "physical uplink shared channel (PUSCH)" are interchangeable to avoid confusion.

[0048] The terms "downlink control signal" and "downlink control information (DCI)" or "physical downlink control channel (PDCCH)" are interchangeable, and the terms "downlink data signal" and "downlink data information" or "physical downlink shared channel (PDSCH)" are interchangeable.

[0049] In addition, sending or receiving PUSCH can be understood as sending or receiving uplink data carried by PUSCH, sending or receiving PUCCH can be understood as sending or receiving uplink information carried by PUCCH, and sending or receiving PRACH can be understood as sending or receiving preamble carried by PRACH; uplink signals can include uplink data signals and / or uplink control signals, etc., and can also be referred to as uplink transmission (UL transmission) or uplink information or uplink channels. Sending uplink transmission on uplink resources can be understood as sending the uplink transmission using the uplink resources. Similarly, downlink data / signals / channels / information can be understood accordingly.

[0050] In the embodiments of the present application, the high-layer signaling may be, for example, radio resource control (RRC) signaling; for example, an RRC message, including, for example, MIB, system information, or a dedicated RRC message; or an RRC information element (RRC IE). The high-layer signaling may also be, for example, MAC (Medium Access Control) signaling; or a MAC control element (MAC CE). However, the present application is not limited thereto.

[0051] The following describes the scenarios of the embodiments of the present application through examples, but the present application is not limited thereto.

[0052] Figure 1 is a schematic diagram of the communication system of the present application, which schematically illustrates the situation taking a terminal device and a network device as an example. As shown in Figure 1, the communication system 100 may include network devices 101, 103 and a terminal device 102 (for simplicity, Figure 1 only illustrates one terminal device as an example).

[0053] In an embodiment of the present application, for example, the terminal device 102 may communicate with one of the network devices 101 and 103 in sequence. Taking the communication between the terminal device 102 and the network device 101 as an example, existing services or future services that can be implemented can be carried out between the network device 101 and the terminal device 102. For example, these services include but are not limited to: enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC), etc.

[0054] Among them, the terminal device 102 can send data to the network device 101, for example, using authorization (for example, a configured authorization, i.e., a configured grant) or an authorization-free transmission mode. In the authorization mode, the network device 101 can receive data sent by one or more terminal devices 102 in the authorization, and feedback information to the terminal device 102, such as confirmation ACK / non-confirmation NACK information, etc., or indicate a new authorization to the terminal device 102. The terminal device 102 can confirm the end of the transmission process based on the feedback information or the new authorization, or can also perform new data transmission, or can retransmit the data. For the authorization-free transmission mode, the terminal device can transmit new data on the configured authorization, or can retransmit.

[0055] For the random access procedure on a LTM candidate cell under a gNB for early uplink timing advance (UL TA) acquisition, a contention-free random access (CFRA) is triggered by a physical downlink control channel order (PDCCH order) on the serving cell under the gNB. As shown in Figure 2, the serving cell and candidate cell are under the same gNB. The UE sends message 1 (MSG1) to the LTM candidate cell and does not listen for responses from the cell. To support UE power ramping, the UE can retransmit MSG1 as instructed by the network.

[0056] Figure 3 illustrates an inter-cell mobility scenario within the same gNB(-CU). As shown in Figure 3, a terminal device 102 moves from the coverage area of ​​one cell to the coverage area of ​​another cell, requiring a serving cell change at some point. This mobility can be implemented using LTM if the cells involved are within the same gNB / gNB-CU.

[0057] For example, when the terminal device 102 is in cell 1, it receives the LTM candidate configuration including cells 2 / 3 / 4 under the same gNB; when it moves to position B, it executes LTM to cell 2; when it is in position D, it executes LTM to cell 3, that is, subsequent LTM.

[0058] FIG4 is a schematic diagram of an inter-CU LTM scenario, and FIG5 is a schematic diagram of an intra-CU LTM scenario.

[0059] As shown in Figure 4, the UE performs LTM from cell 2 to cell 3, i.e., inter-CU LTM. In inter-CU LTM, the LTM candidate cell configuration includes at least the cell configurations of different CUs; ​​the cell change command (MAC CE) indicates that the candidate cell configuration is associated with an inter-CU cell.

[0060] In addition, the LTM between cell 1 and cell 2, the LTM between cell 3 and cell 4, or the LTM between cell 5 and cell 6 in FIG4 are all intra-CU LTMs.

[0061] As shown in Figure 5, the UE performs inter-cell LTM within the same CU, i.e., intra-CU LTM. In intra-CU LTM, the LTM candidate cell configuration includes at least the cell configuration of the same CU; the cell change command (MAC CE) indicates that the candidate cell configuration is associated with an intra-CU cell.

[0062] Embodiments of the first aspect

[0063] Release 18 (Rel-18) introduced Layer 1 / 2 Triggered Mobility (LTM), which offers improved handover latency and interruption time compared to Layer 3-based mobility. However, LTM introduced in Rel-18 also has some limitations compared to Layer 3 mobility.

[0064] For example, LTM operation only supports inter-cell mobility within the same gNB (same CU). The following scenarios are supported:

[0065] Synchronous reconfiguration of LTM cell change (without security key refresh), and:

[0066] Random access (RA) involving or not involving the target LTM candidate special cell according to the network instruction;

[0067] MAC reset;

[0068] Depends on network indication, i.e., RLC re-establishment and PDCP data resumption (for AM DRBs), or no RLC re-establishment.

[0069] When LTM cell change is executed, if the LTM is triggered on the Master Cell Group (MCG), the UE does not release or clear the service-based access stratum (AS) security configuration associated with the master key. For each SRB / DRB using the master key in the current UE configuration, the UE retains the associated Packet Data Convergence Protocol (PDCP) and Service Discovery Application Profile (SDAP) entities and their state variables, buffers, and timers. All fields related to the SRB / DRB configuration, except for the srb-Identity and drb-Identity fields, are released. Therefore, the current LTM operating cell uses the same AS security before and after the cell change, meaning that security updates / changes are not supported.

[0070] Depending on the network deployment scenario, this significantly limits the opportunities for using LTM. When handing over from cell 1 of gNB1 to cell 2 of gNB2, the UE cannot use LTM and can only use L3 HO, which is a synchronous reconfiguration triggered by the RRC reconfiguration message.

[0071] In order to solve the above problems or at least similar problems, an embodiment of the first aspect of the present application provides a communication method applied to a first node.

[0072] FIG6 is a schematic diagram of a communication method according to an embodiment of the first aspect of the present application. As shown in FIG6 , the communication method includes:

[0073] 601. The first node decides to configure Layer 1 / Layer 2 Triggered Mobility (LTM); and

[0074] 602. The first node sends a first message to the second node, where the first message includes first information about the layer 1 / layer 2 triggered mobility, and the first message is a handover request message or a handover cancel message.

[0075] In at least one embodiment, the first node includes: a network device in which a serving cell of the terminal device is located, or a source network device, for example, a gNB, a gNB-CU, or a gNB-DU.

[0076] In operation 601, the first node decides to configure the layer 1 / layer 2 triggered mobility (LTM) according to a measurement report from a terminal device.

[0077] The first node decides to configure Layer 1 / Layer 2 Triggered Mobility (LTM), including:

[0078] Initiate Layer 1 / Layer 2 Triggered Mobility (LTM) candidate preparation; or

[0079] Initiating Layer 1 / Layer 2 Triggered Mobility (LTM) candidate preparation, where the Layer 1 / Layer 2 Triggered Mobility (LTM) is a cell change between two cells of different network devices (gNB) or network device central unit (gNB-CU); or

[0080] A layer 1 / layer 2 triggered mobility (LTM) candidate preparation is initiated towards the cell of the second node.

[0081] In at least one embodiment, the second node includes a candidate and / or target network device, such as a gNB, a gNB-CU, or a gNB-DU.

[0082] In at least one embodiment, the first information includes at least one of the following:

[0083] A value used to indicate the cause of a Layer 1 / Layer 2 Triggered Mobility (LTM) cell change;

[0084] one or more reference configurations;

[0085] Indication information indicating whether the complete LTM configuration is included;

[0086] Candidate configuration identification (ID);

[0087] Information related to early downlink synchronization, where the information related to early downlink synchronization includes configuration related to a downlink reference signal (DL RS), for example, configuration related to a synchronization signal-physical broadcast channel block (SS-PBCH Block, SSB) and / or a channel state information reference signal (CSI-RS);

[0088] Information related to early uplink synchronization, the information related to early uplink synchronization includes at least one of the following information: random access resources, random access preamble code, and an identifier (ID) for determining whether a timing advance (TA) measurement based on a terminal device (UE) can be used.

[0089] When the first message is a handover request message, the handover request message is used to initially request a Layer 1 / Layer 2 Triggered Mobility (LTM) candidate configuration, or the handover request message is used to modify or replace a previously requested Layer 1 / Layer 2 Triggered Mobility (LTM) candidate configuration. In this case, the first information includes at least one of the following:

[0090] Candidate or target cell identity (ID), e.g., New Radio Cell Global Identifier (NR CGI);

[0091] If the handover request message is used to modify / replace a previously requested LTM candidate configuration, the first information includes a candidate or target radio access network Xn interface application procedure protocol identifier (NG-RAN XnAP ID);

[0092] The estimated arrival probability is used by the first node to indicate to the cell of the second node the possibility of initiating layer 1 / layer 2 triggered mobility (LTM) to the candidate cell, and is used to initiate LTM candidate preparation to the cell of the second node.

[0093] In the case where the first message is a handover cancellation message, the first information includes a list of candidate cells to be cancelled. The list includes one or more second information, each piece of second information indicating one candidate cell, and the candidate cell is a Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cell. The second information in the list includes a candidate or target cell identifier (ID) and / or a candidate configuration identifier (ID).

[0094] As shown in FIG6 , the method further includes:

[0095] 603. When the first message is a handover request message, the second node sends a second message to the first node in response to the first message, wherein the second message is a handover request confirmation message or a handover preparation failure message.

[0096] The handover request confirmation message includes at least one of the following information:

[0097] the first information;

[0098] The target or candidate cell identification (ID) of the request;

[0099] The maximum number of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells prepared in parallel for one terminal device on the second node.

[0100] In some examples, the request message of operation 602 may include first information (e.g., first information A), and the switching request confirmation message of operation 603 may also include first information (e.g., first information B), and the first information included in the request message of operation 602 and the first information included in the switching request confirmation message of operation 603 may be at least partially the same or different.

[0101] As shown in FIG6 , the method further includes:

[0102] 604. The first node receives a third message sent by the second node, where the third message is used to cancel a prepared layer 1 / layer 2 triggered mobility (LTM) cell change.

[0103] In some embodiments, the third message is terminal device associated signaling.

[0104] The third message is a layer 1 / layer 2 triggered mobility (LTM) cell change cancellation, or the third message is used to initiate a layer 1 / layer 2 triggered mobility (LTM) cancellation process.

[0105] In some embodiments, the third message includes at least one of the following information:

[0106] Message type;

[0107] The terminal equipment interface application procedure protocol identifier (UE XnAP ID) allocated on the source and target radio access network (NG-RAN) nodes;

[0108] reason;

[0109] List of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells to be cancelled.

[0110] The list includes at least one of the following information:

[0111] Target or candidate primary cell identification (ID);

[0112] Primary and secondary cell identification (ID);

[0113] Candidate configuration ID.

[0114] In at least some embodiments, when the first node receives the third message, the first node believes that the second node is about to remove (release / consider it invalid, etc.) all references on the second node and the resources previously reserved for the layer 1 / layer 2 triggered mobility (LTM) cell change, which are resources reserved for the first node.

[0115] In at least some other embodiments, when the third message includes a list of Layer 1 / Layer 2 triggered mobility (LTM) candidate cells to be canceled, when the first node receives the third message, the first node believes that the second node is going to remove (release / consider invalid, etc.) the resources previously reserved for the Layer 1 / Layer 2 triggered mobility (LTM) cell change on the candidate cells indicated in the third message, and the reserved resources are resources reserved for the first node.

[0116] In this application, 604 may be an independent step.

[0117] As shown in FIG6 , the method further includes:

[0118] 605. The first node receives a fourth message sent by the second node, where the fourth message is used to transmit timing advance (TA) information.

[0119] In some embodiments, the sending of the fourth message triggers a timing advance (TA) information delivery process, which is a class 2 process.

[0120] FIG7 is a schematic diagram of the transmission process of timing advance (TA) information.

[0121] As shown in Figure 7, the process of transmitting timing advance (TA) information includes:

[0122] 701. The source network device receives advance (TA) information sent by the candidate network device.

[0123] The source network device may be a first node, for example, a source gNB; the candidate network device may be a second node, for example, a candidate gNB.

[0124] In some embodiments, the fourth message uses non-terminal device associated signaling.

[0125] In some embodiments, the fourth message includes at least one of the following information:

[0126] Message type: Timing Advance (TA) information list.

[0127] The timing advance (TA) information list includes at least one of the following information:

[0128] a candidate cell identity (ID), such as, for example, a New Radio Cell Global Identifier (NR CGI);

[0129] Timing Advance (TA) value, which is an integer ranging from 0 to 4095;

[0130] Random access information, such as preamble index, random access network temporary identifier (RA-RNTI), etc.

[0131] The source distributed unit identifier (DU ID);

[0132] The identification of the candidate distributed unit (DU ID);

[0133] Source and / or candidate network device identifiers (e.g., gNB IDs), or the length of the network device identifiers (e.g., gNB IDs).

[0134] In this application, 605 can be an independent step.

[0135] As shown in FIG6 , the method further includes:

[0136] 606. The first node sends a fifth message to the second node, where the fifth message is at least used to notify a layer 1 / layer 2 triggered mobility (LTM) cell change.

[0137] In this application, 606 may be an independent step.

[0138] In some embodiments, the fifth message is further used to convey the transmission configuration indication state (TCI state(s)) selected by the first node.

[0139] The fifth message uses terminal device associated signaling.

[0140] In some embodiments, sending of the fifth message triggers a Layer 1 / Layer 2 Triggered Mobility (LTM) Cell Change Notification procedure.

[0141] FIG8 is a schematic diagram of the LTM cell change notification process.

[0142] As shown in Figure 8, the LTM cell change notification process includes:

[0143] 801. The source network device sends a cell change notification to the candidate / target network device.

[0144] The source network device may be a first node, for example, a source gNB; the candidate / target network device may be a second node, for example, a candidate / target gNB. The cell change notification may be, for example, a CELL SWITCH NOTIFICATION.

[0145] In some embodiments, the fifth message includes at least one of the following information:

[0146] Message type;

[0147] The terminal equipment Xn interface application procedure protocol identifier (UE XnAP ID) allocated on the source and / or target radio access network (NG-RAN) node;

[0148] Cell ID (cell identification);

[0149] Transmission Configuration Indication State Identifier (TCI state(s) ID);

[0150] The source distributed unit identifier (DU ID);

[0151] The identification of the candidate distributed unit (DU ID);

[0152] Source and / or candidate network device identifiers (e.g., gNB IDs), or the length of the network device identifiers (e.g., gNB IDs).

[0153] In some embodiments, the fifth message causes the second node to believe that a layer 1 / layer 2 triggered mobility (LTM) cell change command has been sent to the terminal device, wherein the target cell is indicated in the fifth message.

[0154] The communication method of the present application is described below in conjunction with specific embodiments.

[0155] Figure 9 is a schematic diagram of inter-gNB LTM. The terminal device is represented as a UE, the first node is represented as a source gNB, and the second node is represented as a target gNB. In Figure 9, the number of second nodes is one.

[0156] As shown in Figure 9, inter-gNB LTM includes the following steps:

[0157] 1. The UE in RRC_CONNECTED sends a MeasurementReport message to the Source gNB. The Source gNB decides to configure LTM and initiates candidate cell configuration.

[0158] 2a. The Source gNB sends a Handover Request (HO Request) message to the Target gNB. The HO Request message includes, for example, first information about the LTM (corresponding to operation 602 in FIG. 6 ).

[0159] 2b. The Target gNB sends a Handover Request Acknowledgement (HO Request ACK) message to the Source gNB. The HO Request Acknowledgement message carries an RRC Reconfiguration message including the LTM candidate cell configuration.

[0160] 2. The Source gNB sends an RRCReconfiguration message including the LTM candidate cell configuration to the UE.

[0161] 3. The UE stores the LTM candidate cell configuration and sends an RRCReconfigurationComplete message to the Source gNB.

[0162] 4a. Before receiving the cell change command, the UE performs downlink (DL) synchronization of the candidate cell. The Source gNB can trigger the UE to activate and / or deactivate the TCI state of the LTM candidate cell.

[0163] 4b. Before receiving the cell change command, the UE performs uplink (UL) synchronization of the candidate cell by using UE-based TA measurement (if configured) and / or by sending a preamble to the candidate cell triggered by the Source gNB. When UE-based TA measurement is configured, the UE obtains the TA value of the candidate cell through measurement. Before receiving the cell change command, the UE performs early TA acquisition of the candidate cell as requested by the network. This is done by a CFRA triggered by the PDCCH order from the source cell and then the UE sends a preamble to the indicated candidate cell (the UE may or may not receive a random access response from the network providing the TA value);

[0164] 4c. The Target gNB sends the timing advance information (TA) to the Source gNB. In addition, if the UE receives a random access response (RAR), the Source gNB sends the RAR including the TA value of the candidate cell to the UE.

[0165] 5. The UE performs L1 measurements on the configured candidate cells and sends an L1 measurement report to the Source gNB. L1 measurements should be performed whenever RRC reconfiguration (i.e., step 2) applies.

[0166] 6. The Source gNB decides to perform a cell change to the target cell and triggers the cell change by sending a LTM cell change MAC CE including a target configuration ID indicating the candidate configuration index of the target cell, the beam indicated by the TCI state or DL ​​and UL TCI states, and the timing advance command of the target cell, if applicable (and if the UE does not receive a RAR including the TA value of the candidate cell). The UE switches to the target cell and applies the configuration indicated by the candidate configuration ID.

[0167] 6b. The Source gNB sends a cell switch notification to the Target gNB.

[0168] 7. If the UE does not have a valid TA for the target cell, the UE performs a random access procedure to the target cell;

[0169] 8. The UE completes the LTM cell change procedure by sending an RRCReconfigurationComplete message to the target cell. If the UE has already performed a random access procedure in step 7, the UE considers the LTM cell change to be successfully completed when the random access procedure is successfully completed. For RACH-less LTM, the UE considers the LTM cell change to be successfully completed when it determines that the network has successfully received its first UL data (e.g., an RRCReconfigurationComplete message).

[0170] For subsequent LTM, steps 4a-8 may be performed multiple times using the LTM candidate configuration provided in step 2. That is, subsequent LTM is achieved by repeating the early synchronization, LTM cell change execution, and LTM cell change completion steps without releasing other LTM candidate configurations after each LTM cell change is completed.

[0171] Figure 10 is a schematic diagram of inter-gNB LTM. The terminal device is represented as a UE, the first node is represented as a source gNB, and there are two or more second nodes, each represented as a target gNB and at least one other potential target gNB(s).

[0172] The difference between Figure 10 and Figure 9 is:

[0173] In step 2a, the Source gNB sends a Handover Request (HO Request) message to the Target gNB and other potential Target gNBs.

[0174] In step 2b, the Target gNB sends a Handover Request Acknowledgement (HO Request ACK) message to the Source gNB. The other potential Target gNB(s) send a Handover Preparation Failure (HO Preparation Failure) message to the Source gNB. The process ends for the gNB(s) that sent the HO Preparation Failure message.

[0175] In addition, in step 2b, other potential target gNB(s) may also send a HO request ACK message to the Source gNB, and the subsequent process is the same as

[0176] Steps 4b and 4c of FIG. 9 are the same, but step 6b is not included.

[0177] For other steps in FIG10 , please refer to the relevant description of FIG9 .

[0178] According to the embodiment of the first aspect of the present application, LTM operation can support mobility between cells of different gNBs (different CUs), expand the usage scenarios of LTM, and improve flexibility.

[0179] Embodiments of the second aspect

[0180] The embodiment of the second aspect of the present application provides a communication method, which is applied to a second node. The method corresponds to the communication method of the embodiment of the first aspect.

[0181] As shown in FIG11 , the communication method of the embodiment of the second aspect includes:

[0182] 1101. The second node receives a first message sent by the first node, where the first message includes first information about the layer 1 / layer 2 triggered mobility, and the first message is a handover request message or a handover cancel message.

[0183] In some embodiments, the first node includes: a network device where a serving cell of the terminal device is located, or a source network device; and / or the second node includes: a candidate and / or target network device.

[0184] In some embodiments, the first information includes at least one of the following:

[0185] A value used to indicate the cause of a Layer 1 / Layer 2 Triggered Mobility (LTM) cell change;

[0186] one or more reference configurations;

[0187] Indication information indicating whether the complete LTM configuration is included;

[0188] Candidate configuration identification (ID);

[0189] Information related to early downlink synchronization;

[0190] Information related to early uplink synchronization;

[0191] Candidate or target cell identification (ID);

[0192] Candidate or target radio access network Xn interface application process protocol identifier (NG-RAN XnAP ID);

[0193] Estimated likelihood of arrival.

[0194] In some embodiments, the early downlink synchronization related information includes a downlink reference signal (DL RS) related configuration;

[0195] and / or

[0196] The information related to early uplink synchronization includes at least one of the following information: random access resources, random access preamble, an identifier (ID) for determining whether a timing advance (TA) measurement based on a terminal equipment (UE) can be used;

[0197] and / or

[0198] The estimated arrival probability is used by the first node to indicate, to the cell of the second node, the possibility of initiating layer 1 / layer 2 triggered mobility (LTM) to the candidate cell.

[0199] In some embodiments, the first message is a handover request message:

[0200] The handover request message is used to initially request a Layer 1 / Layer 2 Triggered Mobility (LTM) candidate configuration, or the handover request message is used to modify or replace a previously requested Layer 1 / Layer 2 Triggered Mobility (LTM) candidate configuration.

[0201] In some embodiments, the first message is a handover cancellation message, and the first information includes a list of candidate cells to be cancelled.

[0202] In some embodiments, the list includes one or more second information, one piece of the second information indicates one candidate cell, and the candidate cell is a Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cell.

[0203] In some embodiments, the second information of the list includes candidate or target cell identifications (IDs) and / or candidate configuration identifications (IDs).

[0204] In some embodiments, as shown in FIG11 , the method further includes:

[0205] 1102. When the first message is a handover request message, the second node sends a second message to the first node in response to the first message.

[0206] The second message is a handover request confirmation message or a handover preparation failure message.

[0207] In some embodiments, the handover request confirmation message includes at least one of the following information:

[0208] the first information;

[0209] The target or candidate cell identification (ID) of the request;

[0210] The maximum number of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells prepared in parallel for one terminal device on the second node.

[0211] In some embodiments, as shown in FIG11 , the method further includes:

[0212] 1103. The second node sends a third message to the first node, where the third message is used to cancel the prepared layer 1 / layer 2 triggered mobility (LTM) cell change.

[0213] In some embodiments, the third message is terminal device associated signaling.

[0214] In some embodiments, the third message is a layer 1 / layer 2 triggered mobility (LTM) cell change cancellation, or the third message is used to initiate a layer 1 / layer 2 triggered mobility (LTM) cancellation procedure.

[0215] In some embodiments, the third message includes at least one of the following information:

[0216] Message type;

[0217] The terminal equipment interface application procedure protocol identifier (UE XnAP ID) allocated on the source and target radio access network (NG-RAN) nodes;

[0218] reason;

[0219] List of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells to be cancelled.

[0220] In some embodiments, the list includes at least one of the following information:

[0221] Target or candidate primary cell identification (ID);

[0222] Primary and secondary cell identification (ID);

[0223] Candidate configuration ID.

[0224] In some embodiments, when the first node receives the third message, the first node believes that the second node is about to be removed:

[0225] All references on the second node and resources previously reserved for the layer 1 / layer 2 triggered mobility (LTM) cell change; or

[0226] In the case where the third message includes a list of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells to be cancelled, the resources previously reserved for the Layer 1 / Layer 2 Triggered Mobility (LTM) cells on the candidate cells indicated in the third message are changed.

[0227] In some embodiments, as shown in FIG11 , the method further includes:

[0228] 1104. The second node sends a fourth message to the first node, where the fourth message is used to transmit timing advance (TA) information.

[0229] In this application, 1104 can be an independent step.

[0230] In some embodiments, the sending of the fourth message triggers a delivery process of timing advance (TA) information.

[0231] In some embodiments, the fourth message uses non-terminal device associated signaling.

[0232] In some embodiments, the fourth message includes at least one of the following information:

[0233] Message type: Timing Advance (TA) information list.

[0234] In some embodiments, the timing advance (TA) information list includes at least one of the following information:

[0235] Candidate cell identification (ID);

[0236] Timing Advance (TA) value;

[0237] Random access information;

[0238] The source distributed unit identifier (DU ID);

[0239] The identification of the candidate distributed unit (DU ID);

[0240] Source and / or candidate gNB ID, or the length of the gNB ID.

[0241] In some embodiments, as shown in FIG11 , the method further includes:

[0242] 1105. The second node receives a fifth message sent by the first node, where the fifth message is at least used to notify a layer 1 / layer 2 triggered mobility (LTM) cell change.

[0243] In this application, 1105 can be an independent step.

[0244] In some embodiments, the fifth message is further used to convey a transmission configuration indication state (TCI state(s)) selected by the first node.

[0245] In some embodiments, sending of the fifth message triggers a Layer 1 / Layer 2 Triggered Mobility (LTM) Cell Change Notification procedure.

[0246] In some embodiments, the fifth message uses terminal device associated signaling.

[0247] In some embodiments, the fifth message includes at least one of the following information:

[0248] Message type;

[0249] The terminal equipment Xn interface application process protocol identifier (UE XnAP ID) allocated on the source and / or target radio access network node;

[0250] Cell ID (cell identification);

[0251] Transmission Configuration Indication State Identifier (TCI state(s) ID);

[0252] The source distributed unit identifier (DU ID);

[0253] The identification of the candidate distributed unit (DU ID);

[0254] Source and / or candidate gNB ID, or the length of the gNB ID.

[0255] In some embodiments, the fifth message causes the second node to believe that a layer 1 / layer 2 triggered mobility (LTM) cell change command has been sent to the terminal device, wherein the target cell is indicated in the fifth message.

[0256] Embodiments of the third aspect

[0257] The third aspect of the present application provides a communication device, which is applied to a first node. The device corresponds to the communication method of the first aspect.

[0258] FIG12 is a schematic diagram of a communication device in an embodiment of the third aspect. As shown in FIG12 , the communication device 1200 includes a first processing unit 1201. The first processing unit 1201 controls the first node so that the first node performs the following operations:

[0259] The first node decides to configure Layer 1 / Layer 2 Triggered Mobility (LTM); and

[0260] The first node sends a first message to the second node, where the first message includes first information about the layer 1 / layer 2 triggered mobility, and the first message is a handover request message or a handover cancel message.

[0261] In some embodiments, the first node includes: a network device where a serving cell of the terminal device is located, or a source network device;

[0262] and / or,

[0263] The second node includes: a candidate and / or target network device.

[0264] In some embodiments, the first node decides to configure the layer 1 / layer 2 triggered mobility (LTM) based on a measurement report from a terminal device.

[0265] In some embodiments, the first node decides to configure layer 1 / layer 2 triggered mobility (LTM), including:

[0266] Initiate Layer 1 / Layer 2 Triggered Mobility (LTM) candidate preparation; or

[0267] Initiating Layer 1 / Layer 2 Triggered Mobility (LTM) candidate preparation, where the Layer 1 / Layer 2 Triggered Mobility (LTM) is a cell change between two cells of different network devices (gNB) or network device central unit (gNB-CU); or

[0268] A layer 1 / layer 2 triggered mobility (LTM) candidate preparation is initiated towards the cell of the second node.

[0269] In some embodiments, the first information includes at least one of the following:

[0270] A value used to indicate the cause of a Layer 1 / Layer 2 Triggered Mobility (LTM) cell change;

[0271] one or more reference configurations;

[0272] Indication information indicating whether the complete LTM configuration is included;

[0273] Candidate configuration identification (ID);

[0274] Information related to early downlink synchronization;

[0275] Information related to early uplink synchronization;

[0276] Candidate or target cell identification (ID);

[0277] Candidate or target radio access network Xn interface application process protocol identifier (NG-RAN XnAP ID);

[0278] Estimated likelihood of arrival.

[0279] In some embodiments, the early downlink synchronization related information includes a downlink reference signal (DL RS) related configuration;

[0280] and / or

[0281] The information related to early uplink synchronization includes at least one of the following information: random access resources, random access preamble, an identifier (ID) for determining whether a timing advance (TA) measurement based on a terminal equipment (UE) can be used;

[0282] and / or

[0283] The estimated arrival probability is used by the first node to indicate, to the cell of the second node, the possibility of initiating layer 1 / layer 2 triggered mobility (LTM) to the candidate cell.

[0284] In some embodiments, the first message is a handover request message,

[0285] The handover request message is used to initially request a Layer 1 / Layer 2 Triggered Mobility (LTM) candidate configuration, or the handover request message is used to modify or replace a previously requested Layer 1 / Layer 2 Triggered Mobility (LTM) candidate configuration.

[0286] In some embodiments, the first message is a handover cancel message,

[0287] The first information includes a list of candidate cells to be cancelled.

[0288] In some embodiments, the list includes one or more second information, one piece of the second information indicates one candidate cell, and the candidate cell is a Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cell.

[0289] In some embodiments, the second information of the list includes candidate or target cell identifications (IDs) and / or candidate configuration identifications (IDs).

[0290] In some embodiments, the operations further include:

[0291] The second node sends a second message to the first node in response to the first message,

[0292] The second message is a handover request confirmation message or a handover preparation failure message.

[0293] In some embodiments, the handover request confirmation message includes at least one of the following information:

[0294] the first information;

[0295] The target or candidate cell identification (ID) of the request;

[0296] The maximum number of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells prepared in parallel for one terminal device on the second node.

[0297] In some embodiments, the operations further include:

[0298] The first node receives a third message sent by the second node, where the third message is used to cancel a prepared layer 1 / layer 2 triggered mobility (LTM) cell change.

[0299] In some embodiments, the third message is terminal device associated signaling.

[0300] In some embodiments, the third message is a layer 1 / layer 2 triggered mobility (LTM) cell change cancellation, or the third message is used to initiate a layer 1 / layer 2 triggered mobility (LTM) cancellation procedure.

[0301] In some embodiments, the third message includes at least one of the following information:

[0302] Message type;

[0303] The terminal equipment interface application procedure protocol identifier (UE XnAP ID) allocated on the source and target radio access network (NG-RAN) nodes;

[0304] reason;

[0305] List of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells to be cancelled.

[0306] In some embodiments, the list includes at least one of the following information:

[0307] Target or candidate primary cell identification (ID);

[0308] Primary and secondary cell identification (ID);

[0309] Candidate configuration ID.

[0310] In some embodiments, when the first node receives the third message, the first node believes that the second node is about to be removed:

[0311] All references on the second node and resources previously reserved for the layer 1 / layer 2 triggered mobility (LTM) cell change; or

[0312] In the case where the third message includes a list of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells to be cancelled, the resources previously reserved for the Layer 1 / Layer 2 Triggered Mobility (LTM) cells on the candidate cells indicated in the third message are changed.

[0313] In some embodiments, the operations further include:

[0314] The first node receives a fourth message sent by the second node, where the fourth message is used to transmit timing advance (TA) information.

[0315] In some embodiments, the sending of the fourth message triggers a delivery process of timing advance (TA) information.

[0316] In some embodiments, the fourth message uses non-terminal device associated signaling.

[0317] In some embodiments, the fourth message includes at least one of the following information:

[0318] Message type: Timing Advance (TA) information list.

[0319] In some embodiments, the timing advance (TA) information list includes at least one of the following information:

[0320] Candidate cell identification (ID);

[0321] Timing Advance (TA) value;

[0322] Random access information;

[0323] The source distributed unit identifier (DU ID);

[0324] The identification of the candidate distributed unit (DU ID);

[0325] Source and / or candidate gNB ID, or the length of the gNB ID.

[0326] In some embodiments, the operations further include:

[0327] The first node sends a fifth message to the second node, where the fifth message is at least used to notify a layer 1 / layer 2 triggered mobility (LTM) cell change.

[0328] In some embodiments, the fifth message is further used to convey a transmission configuration indication state (TCI state(s)) selected by the first node.

[0329] In some embodiments, sending of the fifth message triggers a Layer 1 / Layer 2 Triggered Mobility (LTM) Cell Change Notification procedure.

[0330] In some embodiments, the fifth message uses terminal device associated signaling.

[0331] In some embodiments, the fifth message includes at least one of the following information:

[0332] Message type;

[0333] The terminal equipment Xn interface application process protocol identifier (UE XnAP ID) allocated on the source and / or target radio access network node;

[0334] Cell ID (cell identification);

[0335] Transmission Configuration Indication State Identifier (TCI state(s) ID);

[0336] The source distributed unit identifier (DU ID);

[0337] The identification of the candidate distributed unit (DU ID);

[0338] Source and / or candidate gNB ID, or the length of the gNB ID.

[0339] In some embodiments, the fifth message causes the second node to believe that a layer 1 / layer 2 triggered mobility (LTM) cell change command has been sent to the terminal device, wherein the target cell is indicated in the fifth message.

[0340] Embodiments of the fourth aspect

[0341] The fourth aspect of the present application provides a communication device, which is applied to a second node. The device corresponds to the communication method of the second aspect.

[0342] FIG13 is a schematic diagram of a communication device according to an embodiment of the fourth aspect. As shown in FIG13 , the communication device 1300 includes a second processing unit 1301. The second processing unit 1301 controls the second node so that the second node performs the following operations:

[0343] The second node receives a first message sent by the first node, where the first message includes first information about the layer 1 / layer 2 triggered mobility, and the first message is a handover request message or a handover cancel message.

[0344] In some embodiments, the first node includes: a network device where a serving cell of the terminal device is located, or a source network device;

[0345] and / or,

[0346] The second node includes: a candidate and / or target network device.

[0347] In some embodiments, the first information includes at least one of the following:

[0348] A value used to indicate the cause of a Layer 1 / Layer 2 Triggered Mobility (LTM) cell change;

[0349] one or more reference configurations;

[0350] Indication information indicating whether the complete LTM configuration is included;

[0351] Candidate configuration identification (ID);

[0352] Information related to early downlink synchronization;

[0353] Information related to early uplink synchronization;

[0354] Candidate or target cell identification (ID);

[0355] Candidate or target radio access network Xn interface application process protocol identifier (NG-RAN XnAP ID);

[0356] Estimated likelihood of arrival.

[0357] In some embodiments, the early downlink synchronization related information includes a downlink reference signal (DL RS) related configuration;

[0358] and / or

[0359] The information related to early uplink synchronization includes at least one of the following information: random access resources, random access preamble, an identifier (ID) for determining whether a timing advance (TA) measurement based on a terminal equipment (UE) can be used;

[0360] and / or

[0361] The estimated arrival probability is used by the first node to indicate, to the cell of the second node, the possibility of initiating layer 1 / layer 2 triggered mobility (LTM) to the candidate cell.

[0362] In some embodiments, the first message is a handover request message,

[0363] The handover request message is used to initially request a Layer 1 / Layer 2 Triggered Mobility (LTM) candidate configuration, or the handover request message is used to modify or replace a previously requested Layer 1 / Layer 2 Triggered Mobility (LTM) candidate configuration.

[0364] In some embodiments, the first message is a handover cancel message,

[0365] The first information includes a list of candidate cells to be cancelled.

[0366] In some embodiments, the list includes one or more second information, one piece of the second information indicates one candidate cell, and the candidate cell is a Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cell.

[0367] In some embodiments, the second information of the list includes candidate or target cell identifications (IDs) and / or candidate configuration identifications (IDs).

[0368] In some embodiments, the operations further include:

[0369] The second node sends a second message to the first node in response to the first message,

[0370] The second message is a handover request confirmation message or a handover preparation failure message.

[0371] In some embodiments, the handover request confirmation message includes at least one of the following information:

[0372] the first information;

[0373] The target or candidate cell identification (ID) of the request;

[0374] The maximum number of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells prepared in parallel for one terminal device on the second node.

[0375] In some embodiments, the operations further include:

[0376] The second node sends a third message to the first node, where the third message is used to cancel the prepared layer 1 / layer 2 triggered mobility (LTM) cell change.

[0377] In some embodiments, the third message is terminal device associated signaling.

[0378] In some embodiments, the third message is a layer 1 / layer 2 triggered mobility (LTM) cell change cancellation, or the third message is used to initiate a layer 1 / layer 2 triggered mobility (LTM) cancellation procedure.

[0379] In some embodiments, the third message includes at least one of the following information:

[0380] Message type;

[0381] The terminal equipment interface application procedure protocol identifier (UE XnAP ID) allocated on the source and target radio access network (NG-RAN) nodes;

[0382] reason;

[0383] List of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells to be cancelled.

[0384] In some embodiments, the list includes at least one of the following information:

[0385] Target or candidate primary cell identification (ID);

[0386] Primary and secondary cell identification (ID);

[0387] Candidate configuration ID.

[0388] In some embodiments, when the first node receives the third message, the first node believes that the second node is about to be removed:

[0389] All references on the second node and resources previously reserved for the layer 1 / layer 2 triggered mobility (LTM) cell change; or

[0390] In the case where the third message includes a list of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells to be cancelled, the resources previously reserved for the Layer 1 / Layer 2 Triggered Mobility (LTM) cells on the candidate cells indicated in the third message are changed.

[0391] In some embodiments, the operations further include:

[0392] The second node sends a fourth message to the first node, where the fourth message is used to transfer timing advance (TA) information.

[0393] In some embodiments, the sending of the fourth message triggers a delivery process of timing advance (TA) information.

[0394] In some embodiments, the fourth message uses non-terminal device associated signaling.

[0395] In some embodiments, the fourth message includes at least one of the following information:

[0396] Message type: Timing Advance (TA) information list.

[0397] In some embodiments, the timing advance (TA) information list includes at least one of the following information:

[0398] Candidate cell identification (ID);

[0399] Timing Advance (TA) value;

[0400] Random access information;

[0401] The source distributed unit identifier (DU ID);

[0402] The identification of the candidate distributed unit (DU ID);

[0403] Source and / or candidate gNB ID, or the length of the gNB ID.

[0404] In some embodiments, the operations further include:

[0405] The second node receives a fifth message sent by the first node, where the fifth message is at least used to notify a layer 1 / layer 2 triggered mobility (LTM) cell change.

[0406] In some embodiments, the fifth message is further used to convey a transmission configuration indication state (TCI state(s)) selected by the first node.

[0407] In some embodiments, sending of the fifth message triggers a Layer 1 / Layer 2 Triggered Mobility (LTM) Cell Change Notification procedure.

[0408] In some embodiments, the fifth message uses terminal device associated signaling.

[0409] In some embodiments, the fifth message includes at least one of the following information:

[0410] Message type;

[0411] The terminal equipment Xn interface application process protocol identifier (UE XnAP ID) allocated on the source and / or target radio access network node;

[0412] Cell ID (cell identification);

[0413] Transmission Configuration Indication State Identifier (TCI state(s) ID);

[0414] The source distributed unit identifier (DU ID);

[0415] The identification of the candidate distributed unit (DU ID);

[0416] Source and / or candidate gNB ID, or the length of the gNB ID.

[0417] In some embodiments, the fifth message causes the second node to believe that a layer 1 / layer 2 triggered mobility (LTM) cell change command has been sent to the terminal device, wherein the target cell is indicated in the fifth message.

[0418] Embodiments of the fifth aspect

[0419] An embodiment of the fifth aspect of the present application provides a communication system, which may include a network device and a terminal device. The network device may be, for example, the first node, the second node, etc. mentioned above.

[0420] Figure 14 is a schematic diagram of an electronic device according to an embodiment of the fifth aspect. As shown in Figure 14 , electronic device 1400 may correspond to terminal device 102 or network device 101 in Figure 1 . Electronic device 1400 may include a processor 1410 and a memory 1420; memory 1420 stores data and programs and is coupled to processor 1410. It should be noted that this diagram is exemplary; other types of structures may be used to supplement or replace this structure to implement telecommunications or other functions.

[0421] For example, when the electronic device 1400 corresponds to the network device 101 in FIG1 , the processor 1410 may be configured to execute a program to implement the method in the first embodiment and / or the method in the second embodiment;

[0422] For another example, when the electronic device 1400 corresponds to the terminal device 102 in FIG. 1 , the processor 1410 may be configured to execute a program to implement the functions of the user equipment (UE) in FIG. 9 or 10 .

[0423] As shown in Figure 14 , the terminal device 1400 may further include: a communication module 1430, an input unit 1440, a display 1450, and a power supply 1460. The functions of these components are similar to those in the prior art and are not described in detail here. It is worth noting that the terminal device 1400 does not necessarily include all of the components shown in Figure 14 , and these components are not essential. Furthermore, the terminal device 1400 may also include components not shown in Figure 14 , for which reference may be made to the prior art.

[0424] An embodiment of the present application also provides a computer program, wherein when the program is executed in a network device, the program causes the network device to execute the method in the embodiment of the first aspect and / or the method in the embodiment of the second aspect.

[0425] An embodiment of the present application further provides a storage medium storing a computer program, wherein the computer program enables a network device to execute the method in the embodiment of the first aspect and / or the method in the embodiment of the second aspect.

[0426] The above devices and methods of the present application can be implemented by hardware or by a combination of hardware and software. The present application relates to such a computer-readable program that, when executed by a logic component, enables the logic component to implement the devices or components described above, or enables the logic component to implement the various methods or steps described above. The present application also relates to a storage medium for storing the above program, such as a hard disk, a magnetic disk, an optical disk, a DVD, a flash memory, etc.

[0427] The method / device described in conjunction with the embodiments of the present application can be directly embodied as hardware, a software module executed by a processor, or a combination of the two. For example, one or more of the functional block diagrams shown in the figure and / or one or more combinations of functional block diagrams can correspond to various software modules of the computer program flow or to various hardware modules. These software modules can respectively correspond to the various steps shown in the figure. These hardware modules can be implemented by solidifying these software modules, for example, using a field programmable gate array (FPGA).

[0428] The software module may be located in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. A storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium; or the storage medium may be an integral part of the processor. The processor and the storage medium may be located in an ASIC. The software module may be stored in the memory of the mobile terminal or in a memory card that can be inserted into the mobile terminal. For example, if the device (such as a mobile terminal) uses a large-capacity MEGA-SIM card or a large-capacity flash memory device, the software module may be stored in the MEGA-SIM card or the large-capacity flash memory device.

[0429] One or more of the functional blocks and / or one or more combinations of functional blocks described in the accompanying drawings may be implemented as a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any appropriate combination thereof for performing the functions described in this application. One or more of the functional blocks and / or one or more combinations of functional blocks described in the accompanying drawings may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in communication with a DSP, or any other such configuration.

[0430] The present application has been described above in conjunction with specific embodiments. However, those skilled in the art should understand that these descriptions are merely illustrative and are not intended to limit the scope of protection of the present application. Those skilled in the art may make various modifications and variations to the present application based on the spirit and principles of the present application, and such modifications and variations are also within the scope of the present application.

[0431] Regarding the implementation methods including the above embodiments, the following additional notes are also disclosed:

[0432] 1. A communication method, applied to a first node, characterized in that the method comprises:

[0433] The first node decides to configure Layer 1 / Layer 2 Triggered Mobility (LTM); and

[0434] The first node sends a first message to the second node, where the first message includes first information about the layer 1 / layer 2 triggered mobility, and the first message is a handover request message or a handover cancel message.

[0435] 2. The method as described in Note 1, wherein:

[0436] The first node includes: a network device where the serving cell of the terminal device is located, or a source network device;

[0437] and / or,

[0438] The second node includes: a candidate and / or target network device.

[0439] 3. The method as described in Note 1, wherein:

[0440] The first node decides to configure the layer 1 / layer 2 triggered mobility (LTM) based on a measurement report from a terminal device.

[0441] 4. The method as described in Note 1, wherein the first message is a handover cancellation message,

[0442] The first information includes a list of candidate cells to be cancelled, the list includes one or more second information, one second information indicates one candidate cell, the candidate cell is a layer 1 / layer 2 triggered mobility (LTM) candidate cell, and the second information includes a candidate or target cell identifier (ID) and / or a candidate configuration identifier (ID).

[0443] 5. The method as described in Note 1, wherein:

[0444] The method further comprises:

[0445] The first node receives a third message sent by the second node, where the third message is used to cancel a prepared layer 1 / layer 2 triggered mobility (LTM) cell change.

[0446] 6. The method as described in Note 5, wherein:

[0447] The third message includes at least a list of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells to be cancelled, wherein the list includes at least one of the following information:

[0448] Target or candidate primary cell identification (ID);

[0449] Primary and secondary cell identification (ID);

[0450] Candidate configuration ID.

[0451] 7. The method as described in Note 5, wherein:

[0452] When the first node receives the third message, the first node believes that the second node is about to be removed:

[0453] All references on the second node and resources previously reserved for the layer 1 / layer 2 triggered mobility (LTM) cell change; or

[0454] In the case where the third message includes a list of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells to be cancelled, the resources previously reserved for the Layer 1 / Layer 2 Triggered Mobility (LTM) cells on the candidate cells indicated in the third message are changed.

[0455] 8. The method as described in Note 1, wherein:

[0456] The method further comprises:

[0457] The first node receives a fourth message sent by the second node, where the fourth message is used to transmit timing advance (TA) information, wherein:

[0458] The sending of the fourth message triggers the delivery process of timing advance (TA) information; and / or

[0459] The fourth message uses non-terminal device associated signaling.

[0460] 9. The method as described in Note 1, wherein:

[0461] The method further comprises:

[0462] The first node sends a fifth message to the second node, where the fifth message is at least used to notify a layer 1 / layer 2 triggered mobility (LTM) cell change.

[0463] 10. The method as described in Supplementary Note 9, wherein:

[0464] The fifth message causes the second node to believe that a layer 1 / layer 2 triggered mobility (LTM) cell change command has been sent to the terminal device, wherein the target cell is indicated in the fifth message.

Claims

1. A communication device, applied to a first node, characterized in that: The apparatus includes a first processing unit, which controls the first node to perform the following operations: The first node decides to configure Layer 1 / Layer 2 Triggered Mobility (LTM); and The first node sends a first message to the second node, where the first message includes first information about the layer 1 / layer 2 triggered mobility, and the first message is a handover request message or a handover cancel message.

2. The device according to claim 1, wherein The first node decides to configure layer 1 / layer 2 triggered mobility (LTM), including: Initiate Layer 1 / Layer 2 Triggered Mobility (LTM) candidate preparation; or Initiating Layer 1 / Layer 2 Triggered Mobility (LTM) candidate preparation, where the Layer 1 / Layer 2 Triggered Mobility (LTM) is a cell change between two cells of different network devices (gNB) or network device central unit (gNB-CU); or A layer 1 / layer 2 triggered mobility (LTM) candidate preparation is initiated towards the cell of the second node.

3. The device according to claim 1, wherein The first information includes at least one of the following: A value used to indicate the cause of a Layer 1 / Layer 2 Triggered Mobility (LTM) cell change; one or more reference configurations; Indication information indicating whether the complete LTM configuration is included; Candidate configuration identification (ID); Information related to early downlink synchronization; Information related to early uplink synchronization; Candidate or target cell identification (ID); Candidate or target radio access network Xn interface application process protocol identifier (NG-RAN XnAP ID); Estimated likelihood of arrival.

4. The device according to claim 3, wherein The early downlink synchronization related information includes a downlink reference signal (DL RS) related configuration; and / or The information related to early uplink synchronization includes at least one of the following information: random access resources, random access preamble, an identifier (ID) for determining whether a timing advance (TA) measurement based on a terminal equipment (UE) can be used; and / or The estimated arrival probability is used by the first node to indicate, to the cell of the second node, the possibility of initiating layer 1 / layer 2 triggered mobility (LTM) to the candidate cell.

5. The device according to claim 1, wherein The first message is a handover request message, The handover request message is used to initially request a Layer 1 / Layer 2 Triggered Mobility (LTM) candidate configuration, or the handover request message is used to modify or replace a previously requested Layer 1 / Layer 2 Triggered Mobility (LTM) candidate configuration.

6. The device according to claim 1, wherein The first message is a handover cancellation message, The first information includes a list of candidate cells to be cancelled.

7. The device according to claim 1, wherein The operations further include: The second node sends a second message to the first node in response to the first message, The second message is a handover request confirmation message or a handover preparation failure message.

8. The device according to claim 7, wherein The handover request confirmation message includes at least one of the following information: the first information; The target or candidate cell identification (ID) of the request; The maximum number of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells prepared in parallel for one terminal device on the second node.

9. The device according to claim 1, wherein The operations further include: The first node receives a third message sent by the second node, where the third message is used to cancel a prepared layer 1 / layer 2 triggered mobility (LTM) cell change.

10. The device according to claim 9, wherein The third message includes at least one of the following information: Message type; The terminal equipment interface application procedure protocol identifier (UE XnAP ID) allocated on the source and target radio access network (NG-RAN) nodes; reason; List of Layer 1 / Layer 2 Triggered Mobility (LTM) candidate cells to be cancelled.

11. The device according to claim 1, wherein The operations further include: The first node receives a fourth message sent by the second node, where the fourth message is used to transmit timing advance (TA) information.

12. The device according to claim 11, wherein The fourth message includes at least one of the following information: Message type: Timing Advance (TA) information list.

13. The device of claim 12, wherein: The timing advance (TA) information list includes at least one of the following information: Candidate cell identification (ID); Timing Advance (TA) value; Random access information; The source distributed unit identifier (DU ID); The identification of the candidate distributed unit (DU ID); Source and / or candidate gNB ID, or the length of the gNB ID.

14. The device of claim 1, wherein The operations further include: The first node sends a fifth message to the second node, where the fifth message is at least used to notify a layer 1 / layer 2 triggered mobility (LTM) cell change.

15. The apparatus of claim 14, wherein: The fifth message includes at least one of the following information: Message type; The terminal equipment Xn interface application process protocol identifier (UE XnAP ID); Cell ID (cell identification); Transmission Configuration Indication State Identifier (TCI state(s) ID); The source distributed unit identifier (DU ID); The identification of the candidate distributed unit (DU ID); Source and / or candidate gNB ID, or the length of the gNB ID.

16. A communication device, applied to a second node, characterized in that: The apparatus includes a second processing unit, which controls the second node to perform the following operations: The second node receives a first message sent by the first node, where the first message includes first information about the layer 1 / layer 2 triggered mobility, and the first message is a handover request message or a handover cancel message.

17. The apparatus of claim 16, wherein: The operations further include: The second node sends a second message to the first node in response to the first message, The second message is a handover request confirmation message or a handover preparation failure message.

18. The apparatus of claim 16, wherein: The operations further include: The second node sends a third message to the first node, where the third message is used to cancel the prepared layer 1 / layer 2 triggered mobility (LTM) cell change.

19. The apparatus of claim 16, wherein: The operations further include: The second node sends a fourth message to the first node, where the fourth message is used to transfer timing advance (TA) information.

20. The apparatus of claim 16, wherein: The operations further include: The second node receives a fifth message sent by the first node, where the fifth message is at least used to notify a layer 1 / layer 2 triggered mobility (LTM) cell change.

Images