Managing mobility in a network that supports dual connectivity.

Abstract

A 5G new wireless network supporting dual connectivity for user equipment allows the user equipment to simultaneously access the network via a primary cell and a secondary cell. Radio coverage in the primary cell is supported by a master distributed node controlled by a master central node, while radio coverage in the secondary cell is supported by a secondary distributed node controlled by a secondary central node. Embodiments seek to support lower layer dual connectivity mobility of user equipment by providing coordination between the master cell and the secondary cell such that handover decisions can be made at the master distributed node based on lower layer measurements.

Description

Technical Field

[0001] Various exemplary embodiments relate to facilitating handover between cells in a new radio network for a user equipment configured to support dual connectivity.

Background Art

[0002] A new radio 5G network may comprise network nodes formed in a distributed manner such that there is a central node or unit controlling a plurality of distributed nodes or units, each distributed node providing radio coverage via one or more cells. These cells may be smaller than macro cells and thus movement between cells may occur more frequently.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Lower layer mobility (LLM) is considered for networks where handover decisions are made at distributed nodes based on lower layer signal measurements performed at the user equipment. Complexity may arise for user equipment configured to support dual connectivity such that the user equipment is enabled to connect simultaneously to a primary distributed node providing access to a primary serving cell and a secondary distributed node providing access to a secondary serving cell. Handover in the primary cell may affect the configuration of the connection to the secondary cell.

Means for Solving the Problems

[0004] The scope of protection sought for various embodiments of the present disclosure is set forth by the independent claims. Embodiments and features described herein that do not fall within the scope of the independent claims, if any, are to be construed as useful examples for understanding the various embodiments of the present invention.

[0005] In various embodiments, though not necessarily all, of this disclosure, a user device is provided for accessing a wireless access network comprising a master central node and a plurality of master distributed nodes that support providing wireless coverage via a primary cell, wherein the master central node controls the plurality of master distributed nodes, and a secondary central node and at least one secondary distributed node support providing wireless coverage via at least one secondary cell, wherein the secondary central node controls the at least one secondary distributed node, and the user device is enabled to connect simultaneously to a primary distributed node that provides access to a primary serving cell and a secondary distributed node that provides access to a secondary serving cell, thereby providing dual connectivity. The user device is configured to support the following: the user device comprises at least one processor and at least one memory for storing instructions, and when the instructions are executed by at least one processor, the user device causes the user device to: establish dual connectivity connections to at least a primary serving cell and a secondary serving cell; receive a measurement configuration from the master node for performing measurements related to at least a non-serving master cell and a secondary cell in order to enable the serving master distributed node to perform a lower layer mobility dual connectivity handover decision; perform at least a portion of the configured measurements; and send a measurement report related to the performed measurements to the serving master distributed node via a lower layer message.

[0006] For user equipment configured to support dual connectivity, where lower-layer mobility dual connectivity handover decisions are made at the serving master distributed node in relation to primary cell changes, it has been recognized that this may affect the configuration of connectivity with secondary cells in both situations where the serving secondary cell remains the same and situations where the serving secondary cell changes. For example, if the serving secondary cell is located across primary cell boundaries, or if the secondary cell itself changes, the allocated band in the secondary cell may change when the primary cell changes, and therefore any measurements facilitating any handover decision may include measurements related to the secondary cell.

[0007] Therefore, in order for the serving master distributed node to make informed lower-layer dual connectivity handover decisions, user equipment may be provided with measurement configuration information relating to at least the non-serving master cell and the secondary cell. This allows the user equipment to perform at least some of the configured measurements and respond by sending reports relating to the measurements to the serving master distributed node, thereby enabling the user equipment to make informed dual connectivity handover decisions, because the user equipment will have relevant information relating to both the updated secondary cell configuration and the updated primary cell, which would trigger such a handover.

[0008] In some exemplary embodiments, the above measurement report relates to at least the non-serving master cell and secondary cells.

[0009] In some exemplary embodiments, the measurement configuration includes a first configuration comprising an MCG configuration 1 and an associated SCG configuration 1, and a second configuration comprising an MCG configuration 2 and an associated SCG configuration 2.

[0010] SCG Configuration 1 may be a configuration of secondary cells that conforms to MCG Configuration 1, which is a configuration of distributed nodes in one target primary cell, while SCG Configuration 2 may be a configuration of the same secondary cells that conforms to MCG Configuration 2, which is a configuration of distributed nodes in another target primary cell among the target primary cells. The secondary cell may be a target secondary cell, or the secondary cell may be the current serving secondary cell.

[0011] In some exemplary embodiments, MCG configuration 1 includes a P cell ID of a first non-serving master distributed node, and SCG configuration 1 includes at least one PS cell ID (secondary cell identifier) ​​of at least one secondary distributed node.

[0012] In some exemplary embodiments, the measurement configuration is received from the serving master distributed node as a Layer 2 message.

[0013] In some exemplary embodiments, the above measurement includes, namely, at least one of the Layer 1 signal intensity or Layer 1 signal quality measurements.

[0014] A secondary serving cell may also be called a primary secondary cell, and a serving node may also be called a source node.

[0015] In some exemplary embodiments, the user device is further configured to receive cell change instructions indicating a change in the primary serving cell and a change in the configuration of the secondary cell, the cell change instructions being received as part of a Layer 2 message.

[0016] In some exemplary embodiments, the Layer 2 message includes a MAC CE message that triggers the cell change.

[0017] In some exemplary embodiments, the above instructions are received from the serving master distributed node from which the above measurement was sent.

[0018] In some exemplary embodiments, the cell change instruction may include a configuration ID indicating the configuration to be used for the primary cell and the secondary cell in the cell change.

[0019] In some exemplary embodiments, the user device is further configured to respond to the receipt of the cell change instruction by initiating connection procedures with the updated primary serving cell and the secondary serving cell.

[0020] If the configuration changes rather than the secondary cell changing, the connection will be temporarily suspended during this procedure.

[0021] In some exemplary embodiments, the connection procedure may include a random access procedure.

[0022] In some exemplary embodiments, the received cell change instruction includes a change to the secondary serving cell, and the user device responds to the receipt of the cell change instruction to initiate a connection procedure with the updated primary serving cell and the updated secondary serving cell.

[0023] In some exemplary embodiments, the measurement configuration received from the serving master distributed node is received in a wireless resource reconfiguration message.

[0024] In some exemplary embodiments, the plurality of primary cells include a target cell, and the one or more secondary cells include at least one of a target cell or a serving cell.

[0025] In some exemplary embodiments, the user equipment is configured to use the received radio resource configuration information when implementing the connection procedure.

[0026] Although not necessarily all of the present disclosure, according to various embodiments, a master distributed node for supporting radio coverage via a primary cell and providing access to the primary cell to the user equipment is provided according to further aspects, and the user equipment is configured to support dual connectivity such that it can simultaneously connect to the master distributed node and a secondary distributed node that provides access to the secondary serving cell, and the master distributed node becomes a serving master distributed node for the user equipment upon connection of the user equipment, provides access to the primary serving cell, and the master distributed node includes at least one processor and at least one memory for storing instructions, and when the instructions are executed by the at least one processor, causes the master distributed node to at least: receive from the user equipment a measurement report related to at least a non-serving master cell, and make a lower layer mobility dual connectivity handover decision in response to the measurement report.

[0027] In some exemplary embodiments, the master distributed node is configured to make a handover decision for both the secondary cell and the primary cell based on measurements from at least one target primary cell.

[0028] In some exemplary embodiments, the received measurement report is related to at least the non-serving primary cell and the secondary cell.

[0029] Exemplary embodiments provide a measurement report related to at least a target master cell and a secondary cell from a user equipment to a serving master distributed node, and the master distributed node is capable of making a lower layer mobility dual connectivity handover decision based on measurement values for both the primary cell and the secondary cell.

[0030] In some exemplary embodiments, following making the handover decision, the distributed node is further configured to generate a cell change indication indicating a change of the primary serving cell and transmit the cell change indication to the user equipment as part of a layer 2 message.

[0031] In some exemplary embodiments, the cell change indication may include a configuration ID indicating a configuration to be used for the primary cell and the secondary cell in the cell change.

[0032] In some exemplary embodiments, the layer 2 message is transmitted to the user equipment as part of a MAC CE message.

[0033] In some exemplary embodiments, the cell change indication further includes an indication of a cell change for the secondary serving cell.

[0034] In some exemplary embodiments, the distributed node is further configured to transfer a message including measurement configuration information related to at least a non-serving master cell and a secondary cell to the user equipment and transmit the message to the user equipment as part of a radio resource control reconfiguration message.

[0035] In some exemplary embodiments, the configuration for performing measurements related to at least a non-serving master cell and a secondary cell further includes a configuration for connecting to at least the non-serving master cell and the secondary cell.

[0036] In some exemplary embodiments, the measurement configuration information is received from the central master node as part of an L3 message and forwarded as an L2 message.

[0037] In other embodiments, instead of receiving and simply transmitting the measurement configuration information, the measurement configuration information may be received and processed at a distributed node, or the measurement configuration information may be generated at a distributed node prior to transmission to the user equipment.

[0038] In some exemplary embodiments, the distributed node is configured to receive instructions from a central node controlling the distributed node regarding the configuration of a target primary cell and at least one secondary cell for which a measurement is requested; to generate measurement configuration information for the indicated target primary cell and the at least one secondary cell; and to transmit the measurement configuration information to the central node.

[0039] In another exemplary embodiment, the distributed node is configured to receive requests for its measurement configuration from a central node that controls the distributed node, and the central node, in response to receiving the measurement configuration from the distributed node, generates measurement and connectivity configuration information for the target primary cell and the at least one secondary cell.

[0040] In some exemplary embodiments, the at least one secondary cell includes a serving secondary cell, and in some exemplary embodiments, the at least one secondary cell includes at least one target secondary cell.

[0041] Target primary and secondary cells are cells prepared for lower-layer mobility, which are potential handover targets.

[0042] In various embodiments, though not necessarily all of the present disclosure, a central node for controlling a plurality of distributed nodes configured to support providing wireless coverage to a user device via a primary cell is provided, the user device is configured to support dual connectivity by simultaneous connection to a serving master distributed node that supports providing wireless coverage via a primary serving cell and a serving secondary distributed node that supports providing wireless coverage via a secondary serving cell, the central node comprises at least one processor and at least one memory for storing instructions, the instructions, when executed by at least one processor, cause the central node to: determine at least one non-serving master cell to be prepared for lower-layer mobility; generate information indicating the determined non-serving master cell and transmit it to a secondary central node that controls a plurality of secondary distributed nodes configured to support providing wireless coverage to the user device via secondary cells; and receive secondary cell configuration information for the secondary cell associated with the at least one non-serving master cell.

[0043] Multiple primary cells may also be potential target cells for lower-layer mobility handovers.

[0044] In some exemplary embodiments, the central node is configured to generate and transmit the information as a secondary node correction signal.

[0045] In some exemplary embodiments, the central node is configured to generate and transmit the above information as a secondary node addition request signal.

[0046] In some exemplary embodiments, the central node is further configured to generate a measurement and connectivity configuration request indicating a plurality of primary cells and at least one secondary cell for which measurement information is required, in order to enable a serving master distributed node to perform a lower layer mobility dual connectivity handover decision with respect to a plurality of primary cells and at least one secondary cell; transmit the measurement and connectivity configuration request to the serving master distributed node; receive the measurement and connectivity configuration information from the serving master distributed node; generate reconfiguration information for the plurality of primary cells and at least one secondary cell; and transmit the reconfiguration information to the serving master distributed node.

[0047] In some exemplary embodiments, the central node is further configured to generate a measurement and connectivity configuration request that requests measurement and connectivity configuration from the serving master distributed node; transmit the measurement and connectivity configuration request to the serving master distributed node; receive the measurement and connectivity configuration information from the serving master distributed node; generate measurement and connectivity configuration information for a plurality of primary cells and the at least one secondary cell; generate reconfiguration information for the plurality of primary cells and the at least one secondary cell; and transmit the reconfiguration information to the serving master distributed node.

[0048] In various embodiments, though not necessarily all, of this disclosure, a system is provided for providing a radio access network that supports lower-layer mobility for user equipment configured for dual connectivity, the system further comprising a master central node and a plurality of master distributed nodes that support providing radio coverage via a primary cell, the master central node comprising a plurality of master distributed nodes that control the plurality of master distributed nodes and a secondary central node for controlling at least one secondary distributed node, the at least one secondary distributed node supporting providing radio coverage via at least one secondary cell.

[0049] In various embodiments, though not necessarily all, of the present disclosure, a method is provided for use in user equipment to access a radio access network comprising a master central node and a plurality of master distributed nodes that support providing radio coverage through a primary cell, wherein the master central node controls the plurality of master distributed nodes, and a secondary central node and at least one secondary distributed node support providing radio coverage through one or more secondary cells, wherein the secondary central node controls at least one secondary distributed node, and the user equipment is configured to support dual connectivity such that it is possible to connect simultaneously to a primary distributed node that provides access to a primary serving cell and a secondary distributed node that provides access to a secondary serving cell, the method comprising establishing dual connectivity connections to a primary serving cell and a secondary serving cell, receiving a measurement configuration from the master node for performing measurements related to at least a non-serving master cell and a secondary cell in order to enable a serving master distributed node to perform a lower-layer mobility dual connectivity handover decision, performing at least a portion of the configured measurements, and sending a report relating to the performed measurements to the serving master distributed node via a lower-layer message.

[0050] In various embodiments, though not necessarily all, of this disclosure, a computer program is provided which, when executed by a user device, causes the user device to: establish a dual connectivity connection to a primary serving cell and a secondary serving cell; receive a measurement configuration from the master node to perform measurements related to at least the non-serving master cell and the secondary cell in order to enable the serving master distributed node to perform a lower-layer mobility dual connectivity handover decision; perform at least a portion of the configured measurements; and send a report related to the performed measurements to the serving master distributed node via a lower-layer message.

[0051] In various embodiments, though not necessarily all, of the present disclosure, a non-temporary computer-readable medium is provided that stores program instructions for performing at least: establishing dual connectivity connections to a primary serving cell and a secondary serving cell; and performing at least some of the configured measurements in response to a reception from a master node of a measurement configuration for performing measurements related to at least a non-serving master cell and a secondary cell, the measurements enabling the serving master distributed node to perform a lower-layer mobility dual connectivity handover decision.

[0052] In various embodiments, though not necessarily all, of this disclosure, a method is provided that is implemented in a distributed node for supporting wireless coverage via a primary cell and providing access to the primary cell to a user device, wherein the user device is configured to support dual connectivity such that it is enabled to simultaneously connect to the master distributed node and a secondary distributed node providing access to the secondary serving cell, the master distributed node becoming a serving master distributed node for the user device and providing access to the primary serving cell, and the method includes: receiving measurement reports from the user device relating to at least a non-serving master cell, and making a lower layer mobility dual connectivity handover decision for the user device in response to the measurement reports.

[0053] In various embodiments, though not necessarily all, of this disclosure, a computer program is provided which, when executed by a distributed node, causes the distributed node to: receive measurement reports from the user equipment relating to at least a non-serving master cell; and, in response to the measurement reports, make a lower-layer mobility dual connectivity handover decision for the user equipment.

[0054] In various embodiments, though not necessarily all, of this disclosure, a non-temporary computer-readable medium is provided that stores program instructions for performing at least: making a lower-layer mobility dual connectivity handover decision for a user device in response to receiving a measurement report from the user device relating to at least a non-serving master cell.

[0055] In various embodiments, though not necessarily all, of the present disclosure, a method is provided to be implemented in a central node for controlling a plurality of distributed nodes configured to support providing wireless coverage to a user device via a primary cell, wherein the user device is configured to support dual connectivity by simultaneous connection to a serving master distributed node that supports providing wireless coverage via a primary serving cell and a serving secondary distributed node that supports providing wireless coverage via a secondary serving cell, wherein the method includes determining at least one non-serving master cell to be prepared for lower-layer mobility, generating information indicating the at least one determined non-serving master cell and transmitting it to a secondary central node that controls a plurality of secondary distributed nodes configured to support providing wireless coverage to the user device via secondary cells, and receiving secondary cell configuration information for the secondary cell associated with the at least one non-serving master cell.

[0056] In various embodiments, though not necessarily all, of this disclosure, a computer program is provided which, when executed by a central node, causes the central node to: generate a measurement and connectivity configuration request indicating a plurality of primary cells and at least one secondary cell for which measurement information is required, in order to enable a serving master distributed node to perform a lower layer mobility dual connectivity handover decision with respect to a plurality of primary cells and at least one secondary cell; and transmit the measurement and connectivity configuration request to the serving master distributed node.

[0057] In various embodiments, though not necessarily all, of the present disclosure, a user device is provided for accessing a radio access network comprising a master central node and a plurality of master distributed nodes that support providing radio coverage through a primary cell, wherein the master central node controls the plurality of master distributed nodes, and a secondary central node and at least one secondary distributed node support providing radio coverage through at least one secondary cell, wherein the secondary central node controls the at least one secondary distributed node, and the user device is configured to support dual connectivity such that it is enabled to connect simultaneously to a primary distributed node that provides access to a primary serving cell and a secondary distributed node that provides access to a secondary serving cell, wherein the user device includes: means for establishing dual connectivity connections to a primary serving cell and a secondary serving cell; means for receiving a measurement configuration from a master node for performing measurements related to at least a non-serving master cell and a secondary cell in order to enable a serving master distributed node to perform a lower-layer mobility dual connectivity handover decision; means for performing at least a portion of the configured measurements; and means for transmitting a report related to the performed measurements to the serving master distributed node via lower-layer messages.

[0058] In some exemplary embodiments, the user device further includes means for receiving cell change instructions indicating a change in the primary serving cell and a change in the configuration of the secondary cell, the cell change instructions being received as part of a Layer 2 message.

[0059] In some exemplary embodiments, the means for establishing the dual connectivity connection is configured to respond to the receipt of the cell change instruction by initiating a connection procedure with the updated primary serving cell and the secondary serving cell.

[0060] In some exemplary embodiments, the received cell change instruction includes a change to the secondary serving cell, and the means for establishing dual connectivity responds to the receipt of the cell change instruction to initiate a connection procedure with the updated primary serving cell and the updated secondary serving cell.

[0061] In various embodiments, though not necessarily all, of the present disclosure, a master distributed node is provided to support wireless coverage via a primary cell and to provide access to the primary cell to a user device, the user device is configured to support dual connectivity such that it is enabled to connect simultaneously to the master distributed node and a secondary distributed node that provides access to a secondary serving cell, the master distributed node becomes a serving master distributed node for the user device upon connection of the user device and provides access to the primary serving cell, the master distributed node includes: means for receiving measurement reports from the user device relating to at least a non-serving master cell and a secondary cell, and means for determining a handover decision, the means for determining a handover decision responding to the received measurement reports to make a lower layer mobility dual connectivity handover decision for the user device.

[0062] In some exemplary embodiments, the distributed node further includes means for generating a cell change instruction message in response to the handover decision, wherein the cell change instruction indicates a change in the primary serving cell, and means for transmitting the cell change instruction to the user device.

[0063] In some exemplary embodiments, the distributed node further includes means for forwarding messages to the user equipment, the messages including measurement configuration information related to at least a non-serving master cell and a secondary cell.

[0064] In some exemplary embodiments, the distributed node includes means for receiving instructions from a central node controlling the distributed node regarding the configuration of a target primary cell and at least one secondary cell for which measurements are required; means for generating measurement and connectivity configuration information for the indicated target primary cell and the at least one secondary cell; and means for transmitting the measurement and connectivity configuration information to the central node.

[0065] In various embodiments, though not necessarily all of the present disclosure, a central node for controlling a plurality of distributed nodes configured to support providing wireless coverage to a user device via a primary cell is provided, and the user device is configured to support dual connectivity by simultaneous connection to a serving master distributed node that supports providing wireless coverage via a primary serving cell and a serving secondary distributed node that supports providing wireless coverage via a secondary serving cell, and the central node includes: means for determining at least one non-serving master cell to be prepared for lower-layer mobility; means for transmitting information relating to the at least one determined non-serving master cell to a secondary central node that controls a plurality of secondary distributed nodes configured to support providing wireless coverage to the user device via secondary cells; and means for receiving secondary cell configuration information for the secondary cell relating to the at least one non-serving master cell.

[0066] In some exemplary embodiments, the central node further includes: means for generating a measurement and connectivity configuration request indicating a plurality of primary cells and at least one secondary cell for which measurement information is required, in order to enable a serving master distributed node to perform a lower layer mobility dual connectivity handover decision with respect to a plurality of primary cells and at least one secondary cell; and means for generating reconfiguration information for the plurality of primary cells and at least one secondary cell, wherein the transmitting means is configured to transmit the measurement and connectivity configuration request to the serving master distributed node; the receiving means is configured to trigger the means for generating reconfiguration information for the plurality of primary cells and at least one secondary cell in response to the receipt of the measurement and connectivity configuration information from the serving master distributed node; and the transmitting means is configured to transmit the reconfiguration information to the serving master distributed node.

[0067] In various embodiments, though not necessarily all, of the present disclosure, a central node for controlling a plurality of distributed nodes configured to support providing wireless coverage to a user device via secondary cells is provided, the user device being configured to support dual connectivity by simultaneous connection to a serving master distributed node that supports providing wireless coverage via a primary serving cell and a serving secondary distributed node that supports providing wireless coverage via a secondary serving cell, the central node comprising at least one processor and at least one memory for storing instructions, the instructions, when executed by the at least one processor, cause the central node to: receive information about a master cell prepared for lower layer mobility and generate a configuration for at least one secondary cell that conforms to the master cell prepared for lower layer mobility.

[0068] The central node controlling the secondary distributed nodes may respond to information about the master cell prepared for lower-layer mobility, i.e., the target master cell, by generating configuration information about one or more secondary cells that match the target master cell, so as to prevent user equipment capabilities from being exceeded when the central node connects to the target master cell and secondary cells.

[0069] The generated configuration information may include frequency layers and measurement identities that can be used by secondary cells.

[0070] The central node may send this configuration information in a response to add or modify a secondary node.

[0071] The central node may also receive information from the central node controlling the master distributed nodes regarding the master cells being prepared for lower-layer mobility.

[0072] Further specific and preferred embodiments are described in the attached independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as necessary, and may also be combined with features other than those expressly described in the claims.

[0073] Several exemplary embodiments are described herein with reference to the accompanying drawings. [Brief explanation of the drawing]

[0074] [Figure 1] This figure shows an exemplary message exchange that may be used to enable lower-layer mobility. [Figure 2A] This diagram schematically illustrates a user equipment handover where the master cell is changed, but the secondary serving cell remains unchanged. [Figure 2B]This diagram shows a user equipment handover where both the master cell and secondary cell are changed. [Figure 3A] This diagram illustrates the steps involved in setting up dual connectivity before lower-layer mobility, with a serving cell configuration modification and simultaneous intra-master node handover occurring. [Figure 3B] This diagram illustrates the steps involved in setting up dual connectivity before lower-layer mobility, with a serving cell configuration modification and simultaneous intra-master node handover occurring. [Figure 3C] This diagram illustrates the steps involved in setting up dual connectivity before lower-layer mobility, with a serving cell configuration modification and simultaneous intra-master node handover occurring. [Figure 4A] This diagram illustrates the steps involved in setting up lower-layer mobility before dual connectivity, with simultaneous master node and secondary node handovers in place. [Figure 4B] This diagram illustrates the steps involved in setting up lower-layer mobility before dual connectivity, with simultaneous master node and secondary node handovers in place. [Figure 4C] This diagram illustrates the steps involved in setting up lower-layer mobility before dual connectivity, with simultaneous master node and secondary node handovers in place. [Figure 5] This diagram shows a network comprising a master central node, a master distributed node, a secondary central node, and a secondary distributed node, according to one embodiment. [Modes for carrying out the invention]

[0075] Before discussing exemplary embodiments in more detail, an overview is first provided.

[0076] Lower Layer Mobility (LLM), also marked as L1 / 2 inter-cell mobility, is a future goal for increasing mobility in new wireless networks. According to the paradigm, decisions regarding cell changes are made at the L2 MAC (medium access control) layer of a distributed unit or node (DU) based on Layer 1 measurements (physical layer). Figure 1 schematically shows the message exchange in such an inter-DU LLM scenario. In short: The UE provides L3 measurements to the source DU, and the L3 measurements are forwarded to the CU-CP (central unit control plane) (step 1). Based on these measurements, the CU-CP decides on cell preparation (HO decision) and proceeds to set up the context for the target DU (steps 4-5). The CU-CP communicates with the CU-UP (central unit user plane) to carry out bearer context setup (steps 6-7). In step 8, the CU-CP forwards the RRC reconfiguration message to the source DU using DL RRC message forwarding, and the source DU forwards the RRC reconfiguration message to the UE (step 9). The UE responds with RRC reconfiguration complete, and RRC reconfiguration complete is then forwarded to the CU-CP (steps 10-11). Based on its configuration, the UE provides the source DU with periodic L1 reports (Step 12). When the source DU determines that the UE should be handed over to another DU (i.e., the target DU), the source DU triggers the handover using MAC CE (step 13). By this point, the UE has received data from the serving DU. Subsequently, the UE applies the RRC configuration to the target cell indicated by the MAC CE and performs Random Access (RA) to the target cell (steps 15-16). After the RA procedure, the UE sends RRC reconfiguration completion to the target cell, and the RRC reconfiguration completion is forwarded to the CU-CP (steps 17-18). CU-CP performs bearer modifications by CU-UP to update the bearer setup and to initiate (and stop) the transfer of data to the target DU by CU-UP (steps 19-20). Once this is complete, the UE begins receiving data from the target DU (step 21). Finally, CU-CP releases the UE context from the source DU using a UE context release request (steps 22-23).

[0077] Subsequently, the handover decision is made at the DU using measurements from the lower layers. When dual connectivity is supported, problems can arise because changes to the primary cell may change the configuration of the secondary cell, and / or the secondary cell itself. Therefore, the master distributed unit may need information about one or more secondary cells, as well as information about the target master cell, to facilitate the decision-making process. This may require some degree of coordination between the master node and the secondary nodes.

[0078] It should be understood that the master central node and secondary central node may be a single entity configured to control both the secondary distributed nodes and the master distributed nodes in an isolated architecture.

[0079] The potential issues that may arise with handover in networks supporting dual connectivity are schematically illustrated in Figures 2A and 2B. Figure 2A shows an intra-master node (MN) handover without secondary node or cell modification, while Figure 2B shows an intra-MN handover with secondary node modification.

[0080] Figure 2A shows two primary cells 22 and 24, each having master distributed nodes DU1 and DU2, as well as secondary cells 30, 32, and 34. Primary cell 22 is the current serving cell for user device 10, while secondary cell 34 is a secondary serving cell for user device 10, spanning both primary cells 22 and 24. User device 10 is shown moving between cells 30 and 32 and reaching cell 34. The handovers from cells 30 to 32 and from 32 to 34 proceed without issue, as they are within master cell 22 and therefore only require the application of secondary node modifications, and do not require coordination with the master node. However, upon reaching cell 34, user device 10 may request a handover from primary cell 22 to primary cell 24. Here, user device 10 does not change the secondary cell remaining within cell 34, but this change may require coordination between the master node and the secondary node. This is because, compared to DU1, there is a possibility of updates or changes to the distributed node configuration DU2, which may affect secondary cells. These configuration changes may include frequency, band, carrier, security key, etc. Since the secondary cell group configuration is affected by the master cell group configuration, preparing for and executing the use of lower-layer mobility is not feasible unless some degree of coordination is provided between the master node and the secondary nodes.

[0081] For example, if the allocation bands for master DU1 to the UE are B1 and B2, and master distributed unit DU2 needs to allocate to B1, B4, and B5, and it changes the secondary component carrier portion, any change in the serving secondary cell depends entirely on whether the primary cell secondary carrier component has been executed or not, and therefore coordination between the master node and the secondary node is required in such a scenario.

[0082] Figure 2B shows UE10 moving from primary cell 22 to primary cell 24 and simultaneously from secondary cell 34 to secondary cell 36. Therefore, a handover is required for both primary and secondary cells. Again, there is the possibility of updating / changing the master distributed node (DU1 and DU2) configuration in terms of frequency, band, carrier, security key, etc., and therefore, if master node unit DU1 is assigned bands B1, B2, B3 to the UE, but master distributed unit 2 needs to change the assignment to B1, B4, B5, this will change the secondary cell group portion, and therefore coordination is also required.

[0083] The embodiment attempts to provide coordination between the master node (MN) and the secondary node (SN) to enable LLM handover decisions to be made at the serving master distributed node for user devices supporting dual connectivity, and these handovers will affect the secondary cell if simultaneous handovers exist in both the master cell and the secondary cell, or because the configuration of the serving secondary cell will change when the master cell changes.

[0084] Two scenarios are possible. First, the DC (dual connectivity) is already set up, and the MN (master node) may inform the SN (secondary node) which cell the MN will constitute, which may be sent in an SN modification request, and the SN will respond by providing a secondary cell group (SCG) configuration for the requested SN modification. The MN can then prepare an LLM configuration for both the secondary cell and the master cell and provide the LLM configuration to the UE.

[0085] Scenario 2: In this case, the LLM is set up by the MN before the DC. When the MN decides to set up the DC, it provides the SN with information about which cells the MN has configured using the LLM, in which case an SN additional request is used. The SN will respond by providing the respective SCG configurations, and the MN will then prepare the LLM configurations for both the secondary and master cells and provide the LLM configurations to the UE.

[0086] The advantage of this collaboration is that it enables LLM using DC, which would normally be impossible in the case of intraMN HO (handover) with different configurations.

[0087] The L1 / L2-based inter-cell mobility procedure is for the following scenarios, namely: • Standalone, CA, and NR-DC (Carrier Aggregation and New Wireless Dual Connectivity) examples with serving cell changes within a single CG (Configured Grant). • Intra-DU examples, intra-CU examples, and inter-DU examples (applicable to standalone and CA: no new RAN interfaces are expected) Both same frequency and different frequencies Both FR1 (4.1GHz~7.125GHz) and FR2 (24.25GHz~52.6GHz) Source and target cells may or may not be synchronized. It may be applicable to this as well.

[0088] As shown in Figures 2A and 2B, when dual connectivity is present, two types of mobility can be distinguished: 1) intraSN (Secondary Node) Modification - PS cell (Primary cell or Serving Secondary Group cell) changes within the same SN. 2) intraMN (master node) handover - P cell (primary cell) changes within the same MN.

[0089] When the Master Node (MN) initiates the procedure to configure the Data Center (DC), it sends an SN Addition Request message to the SN (TS37.340). In this message, the MN provides its configuration, including the frequency layer and measurement identity that may be used by the SN, to ensure that the UE's capabilities are not exceeded. The SN must conform to this configuration. When the UE performs an intraMN handover, the configuration described above may change, and new coordination may be required.

[0090] The embodiment aims to provide a framework that enables the configuration of an LLM for a UE configured using dual connectivity.

[0091] Embodiments include: 1) Once the LLM is set up and its respective configuration is provided to the UE, an attempt is made for communication between the MN and SN. 2) When necessary, we will attempt to enable simultaneous intraMN HO and SN correction. a. Enable the UE to provide the SN's target PS cell (primary secondary cell or secondary serving cell) measurements to the MN's source DU. b. Based on available measurements, the source MN DU can make decisions regarding simultaneous intraMN HO and SN corrections.

[0092] How nodes cooperate during the preparation phase: • 1: The source MN provides the SN with a list of P cells (primary cells) prepared for lower-layer mobility in the MN. 2: The SN generates an LLM SCG (Secondary Cell Group) configuration for the SN's prepared target PS cell, which is applied when lower-layer mobility is performed. 3:SN is as follows, that is, 〇 SCG configuration for SN-prepared target PS cell for lower layer mobility ○ Measurement timing configuration for prepared target PS cells: SSB (synchronization signal block) periodicity, SSB index location, SS / PBC power ○ CSI resource configuration (channel status information) and TCI (transmission configuration indicator) status of the prepared target PS cell. Provide MN with at least one of the following. 4: The MN's CU communicates the CSI resource configuration and TCI status of the prepared PS cells within the SN to the MN's Serving DU. • 5: The MN's serving DU generates a CSI (channel status information) measurement configuration that includes a configuration for reporting L1 beam measurements for the prepared target P cell and PS cell. It may include at least one of the following.

[0093] In RRC signaling, the method for associating MCG and SCG configurations for LLM with UE is: 6: The source MN generates a DC lower layer mobility configuration consisting of MCG and SCG configurations for LLM in the MCG and SCG. For example, given a TCI state in the SCG, there may be two target configurations that the UE can select, depending on the serving cell of the MCG. • 7:UE reports the MN L1 beam measurement results for target P cell and target PS cell to the Serving DU. In this embodiment, when the UE sends an L1 measurement report to one CG, the UE may also report the current TCI status of the other CG. Based on the TCI status of the other CG, the DU can determine its switching action. 8: The serving DU determines the lower layer mobility using L1 beam measurements received from the UE for the target P cell and target PS cell. 9: The UE receives a lower-layer command from the serving DU to apply a stored DC configuration consisting of an MCG configuration and an SCG configuration. It may include one or more of these.

[0094] Two distinct cases can be identified in LLM and DC collaboration: • Example 1: If the DC is already set up, the source MN may inform the SN which P cells will be configured for the LLM in the SN modification request, and the SN will provide the source MN with the SCG configuration for the requested SN modification. The MN will then prepare the LLM configurations and provide them to the UE. • Example 2: If the LLM is set up in the MN, and the MN then decides to set up the DC, the MN will continue with an SN additional request, providing which P cells the MN configured using the LLM. The SN will then provide the respective SCG configurations, and the MN will then prepare the LLM configurations and provide them to the UE.

[0095] Note: In the isolated architecture, the gNB-CU is common to both the MN and SN. The two are distinguished by the DU, with the MCG-DU (master configuration group-distributed unit) belonging to the MN and the SCG-DU belonging to the SN.

[0096] Figure 3 shows an exemplary message exchange for an inter-DU LLM scenario where dual connectivity is set up prior to setting up lower-layer mobility. Establishing dual connectivity in the UE, which may be seen as Step 0, involves the UE connecting to P cell 1 of DU1 (of MN) and PS cell 1 of DU3 (of SN). DC establishment is described in Section 10.2 of TS37.340. The SN addition procedure involves the MN deciding to provide resources from the SN to the UE based on L3 measurements. In particular, the UE context is established in the SN to provide resources from the SN to the UE. For bearers requiring SCG (secondary cell group) radio resources, this procedure is used to add at least the initial SCG serving cell of the SCG.

[0097] First, in Step 1: The UE is configured to operate in NR-DC with Serving MN (serviced by P cell 1) and Serving SN (serviced by PS cell 1). DU1 supports providing radio coverage within P cell 1, and DU2 supports providing radio coverage within cells 2 and 3. DU3 supports providing radio coverage for a secondary serving cell, sometimes called the primary secondary cell PS cell 1. Within this cell group, there are further secondary cells within cells 2 and 3, DU4, which supports providing radio coverage within cell 2 and DU5 within cell 3, and all of these secondary distributed nodes are controlled by the secondary central node CU2. In Step 2: The UE provides L3 measurements to the serving master or source DU, DU1, and DU1 forwards them to the CU-CP (central unit-control plane) master node CU1. In Step 3: Based on the measurement report from the UE, CU1 decides to set up the LLM for the UE using the possible target cells 2 and 3 of DU2. In step 4: CU1 (of MN) sends an SN correction request (optional according to TS37.340), and CU1 provides CU2 (of SN) with L3 measurement reports for SN's serving and target cells, i.e., PS cell 1, DU4-cell 2, and DU5-cell 3, as well as a list of prepared cells for LLM in MN (DU2-cells 2 and 3), and the respective configurations for these cells. At this point, MN's CU sends information about MN's cells to SN. In step 5: CU2 decides to prepare a cell configuration (in this example, DU5-cell 3) that is relevant for DU2-cell 2 (SCG configuration 1 for DU5-cell 3) and DU2-cell 3 (SCG configuration 2 for DU5-cell 3). That is, CU2 considers the target master cell and prepares the configuration for the secondary cell taking the target master cell into account. In this step, CU2 works in conjunction with DU5 to obtain a measurement timing configuration that includes SSB periodicity and index location, SSB / PBCH power, CSI resource configuration, and TCI status of DU5-cell 3. In step 6: CU2 provides CU1 of MN with the following, namely SCG configuration 1, SCG configuration 2, and measurement timing configuration, which includes SSB periodicity and index location, SSB / PBCH power, CSI resource configuration, and TCI state of DU5-cell 3. This may be provided in SN modified ACK. In steps 7-9: CU1 communicates with the (source or serving) DU (i.e., DU1) to generate the CSI measurement configuration. In this regard, CU1 provides DU1 with the target P cell configuration and the target PS cell configuration. DU1 prepares the CSI measurement configuration for the target P cell and the serving secondary cell PS cell, and in some cases for the target secondary cell, and provides it to CU1. Note: In an alternative execution embodiment, the CU may provide the measurement configuration for the source DU and ask DU1 to generate the CSI measurement configuration within the CU. In step 10: CU1 generates LLM RRC configurations (i.e., MCG configuration 1 and SCG configuration 1, as well as MCG configuration 2 and SCG configuration 2) for the target P cell using DC. SCG configuration 1 is the configuration of cell 3 that matches the configuration of DU2 cell 2; SCG configuration 2 is the configuration of cell 3 that matches the configuration of DU2 cell 3; each SCG configuration is identified by a unique identifier, and among other things, each SCG configuration includes: SSB periodicity and index location, SSB / PBCH power, CSI resource configuration, and measurement timing configuration including the TCI state of DU5-cell 3; each SCG configuration may also include the cell ID of DU5-cell 3 (e.g., PCI). Each SCG configuration may also include the assigned frequency band used / measured, the frequency carrier used / measured, and the security key used after HO. SCG configuration 1 and SCG configuration 2 are different because they must be compatible; MCG configuration 1 is the configuration for DU2 cell 2; MCG configuration 2 is the configuration for DU2 cell 3; similar to the SCG configuration, the MCG configuration is identified by a unique identifier, and among other things, the MCG configuration includes: SSB periodicity and index location, SSB / PBCH power, CSI resource configuration, and measurement timing configuration including TCI status of DU5-cell 3; the MCG configuration may also include cell ID (e.g., PCI); the MCG configuration may also include the assigned frequency band used / measured, the frequency carrier used / measured, and a security key used after HO. Steps 11-14: CU1 provides the UE with the RRC configuration for LLM using DC, and MN responds with the completion of RRC reconstruction. Steps 15-18: The UE uses a measurement timing configuration that includes SSB periodicity and index location, SSB / PBCH power, CSI resource configuration, and TCI status of the target cell in order to perform the measurement. Without this configuration, the UE cannot perform the L1 measurement. The UE provides the source DU with an L1 measurement report based on these measurements. These include measurements for DU2-Cell 2, DU2-Cell 3, and optionally DU5-Cell 3. The UE will report using the cell ID of the target cell, so the following measurements will be included: Measurement for serving cells DU2-Cell 2 Measurement DU2-Cell 3 Measurement DU5-Cell 3 Measurement Measurement of other target cells (if any) This will provide a structure having at least a subset of the above. DU1 determines that the UE should perform an LLM HO using DC, and the UE determines which target P cell should be handed over to. MN's DU (step 16) will select MCG configuration 1 and SCG configuration 1 if it receives measurements with high DU2-cell 2 measurements and DU5-cell 3 measurements. DU1 then sends a MAC to the UE to trigger a P cell change with a PS cell configuration update / change, and provides CU1 with information that the UE has triggered an LLM HO. Steps 19-23: The UE terminates the LLM HO by accessing the target cells (P cells and PS cells) and providing the CU1 with the RRC reconfiguration completion. Note: As shown in Figure 2A, the UE may remain within the same PS cell, but it is only necessary to apply the new configuration to that same cell.

[0098] One point to note is that the TCI state is a "Transmission Configuration Indicator" state, which allows a UE to transmit and receive using a specific configuration. Each UE may be configured to have multiple TCI states for serving and non-serving cells, and multiple TCI states are used to enable transmit / receive. Based on the measurements, when the MN DU decides to switch HO and cells, it will trigger the application of the new configuration. The UE will use the TCI state in the indicated configuration to begin transmit / receive. The MN may use a different TCI state within the serving cell, taking into account the UE beam measurements, which would not result in a handover. The use of TCI states occurs in other transmit / receive configuration updates (e.g., in inter-cell beam management).

[0099] Case 2: The LLM is set up before the DC (Figure 4). First, in Step 1: UE is configured to have LLMs related to P cell 1 of DU1 and prepared cells, namely cells 2 and 3 from DU2. Step 2: The UE provides the measurement report to the CU1, and the CU1 decides to set up the DC. Step 3: CU1 sends an SN Addition Request to CU2 (SN) which provides the L3 measurement report and a list of prepared cells for LLM in MN (Cells 2 and 3 of DU2), as well as the respective configurations for these cells. Steps 4-6: CU2 decides to set up LLM for some DUs that do not require interaction with MN and for cell 3 of DU5 that requires interaction with MN. Then CU2 sets up LLM from PS cell of DU3 to cell 2 of DU4 with or without SRB3, while CU2 communicates with DU5 to obtain the CSI measurement configuration for that cell, along with the measurement timing configuration including SSB periodicity and index location, SSB / PBCH power, CSI resource configuration, and TCI state of DU5-cell 3. Step 7: In the SN additional ACK, CU2 provides MN with the following: SCG configuration 1 (for DU2 cell 2), SCG configuration 2 (for DU2 cell 3), as well as the measurement timing configuration including SSB periodicity and index location, SSB / PBCH power, CSI resource configuration, and TCI status of DU5 cell 3. Steps 8-10: CU1 communicates with the (source or serving) DU (i.e., DU1) to generate the CSI measurement configuration. In this regard, CU1 provides DU1 with the target P cell configuration and target PS cell configuration. DU1 prepares the CSI measurement configuration for the target P cell and PS cell and provides it to CU1. Note: In an alternative execution embodiment, the CU may provide the measurement configuration for the source DU and ask DU1 to generate the CSI measurement configuration within the CU. Step 11: CU1 generates LLM RRC configurations (i.e., MCG configuration 1 and SCG configuration 1, as well as MCG configuration 2 and SCG configuration 2) for the target P cell using DC. SCG configuration 1 is the configuration of cell 3 that matches the configuration of DU2 cell 2; SCG configuration 2 is the configuration of cell 3 that matches the configuration of DU2 cell 3; each SCG configuration is identified by a unique identifier, and among other things, each SCG configuration includes: SSB periodicity and index location, SSB / PBCH power, CSI resource configuration, and measurement timing configuration including the TCI state of DU5-cell 3; each SCG configuration may also include the cell ID of DU5-cell 3 (e.g., PCI). Each SCG configuration may also include the assigned frequency band used / measured, the frequency carrier used / measured, and the security key used after HO. SCG configuration 1 and SCG configuration 2 are different because they must be compatible; MCG configuration 1 is the configuration for DU2 cell 2; MCG configuration 2 is the configuration for DU2 cell 3; similar to the SCG configuration, the MCG configuration is identified by a unique identifier, and among other things, the MCG configuration includes: SSB periodicity and index location, SSB / PBCH power, CSI resource configuration, and measurement timing configuration including TCI status of DU5-cell 3; the MCG configuration may also include cell ID (e.g., PCI); the MCG configuration may also include the assigned frequency band used / measured, the frequency carrier used / measured, and a security key used after HO. Steps 12-15: CU1 provides the UE with the RRC configuration for LLM using DC, and MN responds when RRC reconstruction is complete. Steps 16-19: The UE uses a measurement timing configuration that includes SSB periodicity and index location, SSB / PBCH power, CSI resource configuration, and TCI status of the target cell in order to perform the measurement. Without this configuration, the UE cannot perform the L1 measurement. The UE provides the source DU with an L1 measurement report based on these measurements. These include measurements for DU2-Cell 2, DU2-Cell 3, and optionally DU5-Cell 3. The UE will report using the cell ID of the target cell, so the following measurements will be included: Measurement for serving cells DU2-Cell 2 Measurement DU2-Cell 3 Measurement DU5-Cell 3 Measurement Measurement of other target cells (if any) This will provide a structure having at least a subset of the above. DU1 determines that the UE should perform an LLM HO using DC, and the UE determines which target P cell should be handed over to. MN's DU (step 16) will select MCG configuration 1 and SCG configuration 1 if it receives measurements with high DU2-cell 2 measurements and DU5-cell 3 measurements. DU1 then sends a MAC to the UE to trigger a P cell change with a PS cell configuration update / change, and provides CU1 with information that the UE has triggered an LLM HO.

[0100] Steps 20-24: The UE terminates the LLM HO by accessing the target cells (P cells and PS cells) and providing the CU1 with RRC reconfiguration completion. Note: As shown in Figure 2A, the UE may remain within the same PS cell, but it is only necessary to apply the new configuration to that same cell.

[0101] The embodiment offers the following advantages, namely, • Enables LLM using DC, which is not possible in the case of intraMN HO with different configurations. • The serving DU within the MN enables lower layer mobility determination based on L1 beam measurements for target P cells and target PS cells controlled by different SNs. • In the case of simultaneous intraMN HO with SN correction, the configuration is provided to the UE by a single RCC reconstruction message instead of two RCC reconstruction messages leading to the signaling gain. In the case of an LLM within a SN, the SN would need to trigger interaction with the MN before starting the process; this way the SN can do this proactively, which leads to signaling gains. You may provide one or more of these.

[0102] Figure 5 schematically shows a new 5G wireless network according to one embodiment. This network comprises multiple primary cells 22, 24 and multiple secondary cells 32, 34. Wireless coverage within primary cell 22 is supported by master distributed node 21, while master distributed node 26 supports providing wireless coverage within primary cell 24. Both master distributed node 21 and master distributed node 26 are controlled by master central node 41.

[0103] Secondary cells 32 and 34 exist, and wireless coverage within these cells is supported by secondary distributed nodes 31 and 33, respectively. Secondary distributed nodes 31 and 33 are controlled by a secondary central node 35. In this embodiment, user device 10 is currently connected to secondary cell 34, which is supported by secondary distributed node 33, and primary cell 24, which is supported by distributed node 26. Therefore, user device 10 is operating in dual connectivity mode. In this embodiment, user device 10 moves from secondary cell 34 to secondary cell 32, and simultaneously moves from master cell 24 to master cell 22.

[0104] The embodiment allows such a handover decision regarding movement to be made at the master distributed node 26, which is currently the master serving distributed node, sometimes referred to as the source master distributed node for the user device 10.

[0105] The user device 10 includes a receiver 16 for receiving signals, which may be means for receiving or a circuit configured to receive. The user device 10 further includes means for establishing dual connectivity 17, which may be a circuit configured to establish dual connectivity, and means for performing measurements 18, which may also be a circuit configured to perform measurements, which may be L1 signal strength and / or quality measurements. The user device 10 also includes a transmitter 19 or means for transmitting. The receiver 16 may receive measurement configuration information from the distributed node 26 for performing measurements related to a non-serving master cell, in this case cell 22, and a secondary cell, in this case cell 32, which are two cells for target handover. The user device may respond to the receipt of this by performing measurements on these cells and sending a measurement report to the distributed node 26.

[0106] This is merely an example, and in other embodiments, there may be more cells for which measurement configuration information is received and measurements are performed. In other embodiments, a serving secondary cell may span two master cells, in which case the measurements performed on the secondary cell may relate to the current serving secondary cell, but the measurements may, in the case of this cell, be, for example, about a reconfigured frequency band.

[0107] The serving master distributed node 26 includes a receiver 51, which may be receiving means or a circuit configured to receive measurement reports, and makes a handover decision relating to the cell to be handed over in response to the use of decision-making means 52 or a circuit configured to perform the handover decision. Following the handover decision, the serving master distributed node 26 uses means for generating cell change instructions 53 or a circuit configured to generate them to generate cell change instructions indicating any changes to the primary serving cell and secondary cell determined in the handover decision. The serving master distributed node 26 then transmits this information to user equipment as part of a Layer 2 message using means for transmission 54.

[0108] Prior to the user equipment receiving the measurement configuration information and the above steps being performed, there must be some degree of coordination between the secondary node and the master central node.

[0109] The serving master central node 41 will work in conjunction with the serving secondary central node 35 to determine any corresponding changes that may be required in the configuration of the primary and secondary cells prepared for lower-layer mobility, and / or the configuration of the secondary cells prepared for lower-layer mobility.

[0110] The master central node 41 will use means or a circuit 43 configured to determine the primary cell to be prepared for lower-layer mobility, and will transmit this information to the secondary central node 35 using transmission means 45 or a circuit configured to transmit it as a secondary node addition request or a secondary node modification request.

[0111] The secondary central node 35 may receive this information at the receiver 37 and, in response to using means 36 for generating configuration information or circuitry configured to generate configuration information, generate a configuration for at least one secondary cell that fits the master cell prepared for lower layer mobility, and transmit this configuration information using the transmitter 38 in a secondary node addition or secondary node modification response.

[0112] The master central node 41 has means 47 for receiving or a circuit configured to receive and receives this secondary cell configuration information. The master central node 41 then exchanges information with the serving master distributed nodes to generate reconfiguration information for the primary cells and at least one reconfigured secondary cell using means 42 for generating measurement configuration requests or a circuit configured to generate such requests, the configuration requests indicating multiple primary cells and at least one secondary cell that require measurement information. This is transmitted to the serving master distributed nodes using transmission means 45.

[0113] The serving master distributed node 26 receives this at the receiver 51 and transfers the measurement configuration information to the user device 10 using means 55 for transfer, so that the user device can perform the measurements described above.

[0114] The following description may provide further details on alternatives, modifications, and variations: gNB comprises a node that provides, for example, NR user plane and control plane protocol terminations to the UE and is connected to 5GC by an NG interface, in accordance with Section 3.2 of 3GPP® TS 38.300 V16.6.0 (2021-06), incorporated by reference.

[0115] The following description may provide further details on alternatives, modifications, and variations: gNB comprises a node that provides, for example, NR user plane and control plane protocol terminations to the UE and is connected to 5GC by an NG interface, in accordance with Section 3.2 of 3GPP TS 38.300 V16.6.0 (2021-06), incorporated by reference.

[0116] The gNB Central Unit (gNB-CU) controls the operation of one or more gNB-DUs and includes, for example, logical nodes that host the gNB's RRC (radio resource control), SDAP (service data adaptation protocol), and PDCP (packet data convergence protocol), or the en-gNB's RRC and PDCP protocols. The gNB-CU terminates the F1 interface connected to the gNB-DUs.

[0117] A gNB distributed unit (gNB-DU) includes, for example, a logical node that hosts the RLC (radio link control), MAC (medium access control), and PHY (physical) layers of a gNB or en-gNB, and its operation is partially controlled by a gNB-CU. A single gNB-DU supports one or more cells. A single cell is supported by only one gNB-DU. A gNB-DU terminates an F1 interface connected to a gNB-CU.

[0118] The gNB-CU-UserPlane (gNB-CU-UP) comprises, for example, logical nodes that host the user plane portion of the gNB-CU PDCP protocol for en-gNB and the user plane portions of the gNB-CU PDCP protocol and SDAP protocol for gNB. The gNB-CU-UP terminates the E1 interface connected to the gNB-CU-CP and the F1-U interface connected to the gNB-DU, for example, according to Section 3.1 of 3GPP TS 38.401 V16.6.0 (2021-07), which is incorporated by reference.

[0119] Different functional divisions are possible between the central unit and distributed units, for example, called options: Option 1 (1A-type division): - The functional partitioning in this option is similar to the 1A architecture within the DC. The RRC is located in the central unit. The PDCP, RLC, MAC, physical layer, and RF are located in the distributed units. Option 2 (3C-style division): - The functional partitioning in this option is similar to the 3C architecture within a data center. RRC and PDCP are located in the central unit. RLC, MAC, physical layer, and RF are located in the distributed units. Option 3 (intraRLC splitting): - Low RLC (a partial function of RLC), MAC, physical layer, and RF are located in the distributed unit. PDCP and high RLC (other partial functions of RLC) are located in the central unit. Option 4 (RLC-MAC splitting): - MAC, physical layer, and RF are located in the distributed unit. PDCP and RLC are located in the central unit. Otherwise, follow, for example, Section 11 of 3GPP TR 38.801 V14.0.0(2017-03), which is incorporated by reference. gNB supports different protocol layers, such as Layer 1 (L1) to the physical layer.

[0120] NR Layer 2 (L2) consists of the following sublayers: Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and Service Data Adaptive Protocol (SDAP). It is divided into, and here, for example: - The physical layer provides a transport channel to the MAC sublayer. - The MAC sublayer provides logical channels to the RLC sublayer. - The RLC sublayer provides an RLC channel to the PDCP sublayer. - The PDCP sublayer provides wireless bearers to the SDAP sublayer. - The SDAP sublayer provides QoS flow to 5GC. - Comp. refers to header compression, and Segm. refers to segmentation. - The control channels include (BCCH, PCCH).

[0121] Layer 3 (L3) includes, for example, Radio Resource Control (RRC) according to Section 6 of 3GPP TS 38.300 V16.6.0 (2021-06), which is incorporated by reference.

[0122] RAN (Radio Access Network) nodes, network nodes, central nodes, or distributed nodes, such as gNBs, base stations, gNB CUs, or gNB DUs, or parts thereof, may be executed using a device having at least one processor and / or at least one memory (having computer-readable instructions (computer programs)) configured to support and / or supply and / or process at least one protocol (sub)layer of the RAN (Radio Access Network), such as Layer 2 and / or Layer 3. They may also be executed using specific means configured to perform their respective specific tasks, such as Layer 3 means for performing Layer 3 operations, Layer 2 means for performing Layer 2 operations, and so on.

[0123] The gNB CU and gNB DU portions may, for example, be installed in the same location or be physically separated. The gNB DU may be further divided into, for example, two parts, such as a portion containing processing equipment and a portion containing antennas. The central unit (CU) may be called BBU / REC / RCC / C-RAN / V-RAN, O-RAN, or a portion thereof. The distributed unit (DU) may be called RRH / RRU / RE / RU, or a portion thereof.

[0124] A gNB DU supports one or more cells and therefore can serve as a serving cell for, for example, a user device (UE).

[0125] User equipment (UE) may include wireless or mobile devices, devices having a wireless interface that interacts with a RAN (Radio Access Network), smartphones, in-vehicle devices, IoT devices, M2M devices, or other devices. Such UE or device may include, namely, at least one processor and at least one memory containing computer program code, the at least one memory and computer program code configured to cause the device to perform at least one specific operation using the at least one processor, such as making an RRC connection to the RAN. The UE is configured to generate messages (e.g., including a cell ID) that are transmitted wirelessly to the RAN (e.g., to reach a serving cell and communicate with a serving cell). The UE may generate, transmit, and receive RRC messages containing one or more RRC PDUs (Packet Data Units).

[0126] UE may have different states (for example, according to sections 42.1 and 4.4 of 3GPP TS 38.331 V16.5.0 (2021-06) incorporated by reference).

[0127] When an RRC connection is established, the UE is in a state such as RRC_CONNECTED or RRC_INACTIVE.

[0128] In the RRC_CONNECTED state, the UE is: - The AS context may be remembered. - Unicast data may be transferred to / from UE. - To determine whether data is scheduled for a data channel, you may monitor the control channel associated with the shared data. - Channel quality and feedback information may be provided. - Nearby cell measurements and measurement reporting may be performed.

[0129] The RRC protocol includes, for example, the following main mechanisms: - RRC connection control, - Measurement configuration and reporting, - Establishment / modification / release of measurement configurations (e.g., intra-frequency, inter-frequency, and inter-RAT measurements), - Setting up and releasing the measurement gap, - Measurement reporting Includes.

[0130] Those skilled in the art will readily recognize that the steps of the various methods described above can be carried out by a programmable computer. In this specification, some embodiments are also intended to cover programmable storage devices, such as digital data storage media, which are machine- or computer-readable and encode machine-executable or computer-executable programs of instructions, which carry out some or all of the steps of the methods described above. The programmable storage devices may be, for example, digital memory, magnetic storage media such as magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media. Embodiments are also intended to cover computers programmed to carry out the steps of the methods described above. As used herein, the term "non-transitory" refers to the limitations of the medium itself (i.e., tangible, not signaling) in contrast to limitations on data storage persistence (e.g., RAM vs. ROM).

[0131] As used in this application, the term “circuitry” may refer to one, more, or all of the following: (a) Implementation modes of hardware-only circuits (such as implementation modes using only analog and / or digital circuits), and (b) A combination of hardware circuits and software, for example (if applicable): (i) A combination of analog and / or digital hardware circuits having software / firmware, (ii) A hardware processor (including a digital signal processor), software, and any portion of memory that works together to enable a device such as a mobile phone or server to perform various functions, (c) Hardware circuits and / or processors, such as a microprocessor or a part of a microprocessor, that require software (e.g., firmware) for operation, but may not be present when the software is not required for operation.

[0132] This definition of circuit applies to all use of the term in this disclosure and in any claim. In further embodiments, as used in this application, the term circuit also applies to a hardware circuit or processor (or more processors) or a portion of a hardware circuit or processor and / or its associated software and / or firmware execution modes. The term circuit also applies, for example, to a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, a cellular network device, or other computing or network device, as applicable to a particular claim element.

[0133] While embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be recognized that modifications to the given embodiments can be made without departing from the claimed scope of the invention.

[0134] The features described in the preceding explanation may be used in combinations other than those explicitly described.

[0135] While the functions were described by referring to specific features, these functions may also be achievable by other features, whether or not they were described.

[0136] Features have been described with reference to specific embodiments, but these features may be present in other embodiments, whether described or not.

[0137] While the above specification endeavors to draw attention to features of the invention that seem particularly important, it should be understood that the applicant seeks protection for any of the above patentable features or combinations of features, whether or not they are emphasized, with reference to and / or shown in the drawings.

Claims

1. A user device for accessing a wireless access network comprising a master central node and a plurality of master distributed nodes that support providing wireless coverage via a primary cell, wherein the master central node controls the plurality of master distributed nodes, and a secondary central node and at least one secondary distributed node support providing wireless coverage via at least one secondary cell, and the secondary central node controls the at least one secondary distributed node, and the user device is configured to support dual connectivity such that it is possible to connect simultaneously to a primary distributed node that provides access to a primary serving cell and a secondary distributed node that provides access to a secondary serving cell, and the user device is, At least one processor, The system comprises at least one memory for storing instructions, and when an instruction is executed by the at least one processor, it provides at least the following to the user device: To establish dual connectivity to the primary serving cell and the secondary serving cell, The serving master node receives a configuration to perform at least measurements related to the non-serving master cell and secondary cell in order to enable the serving master distributed nodes to perform lower-layer mobility dual connectivity handover decisions, Performing at least a portion of the measurements configured above, The report related to the measurements performed above is sent to the serving master distributed node via a lower-layer message. User equipment that enables this.

2. The user device according to claim 1, wherein the report relates to at least a non-serving master cell and a secondary cell.

3. The user device according to claim 1, wherein the configuration for performing the measurement includes a first configuration comprising a master cell group configuration MCG configuration 1 and an associated secondary cell group configuration SCG configuration 1, and a second configuration comprising a master cell group configuration MCG configuration 2 and an associated secondary cell group configuration SCG configuration 2.

4. The user device according to claim 1, wherein the measurement includes, namely, at least one of a Layer 1 signal intensity or a Layer 1 signal quality measurement.

5. The user device according to claim 1, further configured to receive cell change instructions indicating a change in the primary serving cell and a change in the configuration of a secondary cell, wherein the cell change instructions are received as part of a Layer 2 message.

6. The user device according to claim 5, further configured to respond to the receipt of a cell change instruction by initiating a connection procedure with the updated primary serving cell and the secondary serving cell.

7. The received cell change instruction includes the change of the secondary serving cell, The user device according to claim 6, wherein the user device responds to the receipt of the cell change instruction in order to initiate a connection procedure with the updated primary serving cell and the updated secondary serving cell.

8. The configuration for performing the measurement is a user device according to any one of claims 1 to 7, which is received from the serving master distributed node in a wireless resource reconfiguration message.

9. A master distributed node for supporting wireless coverage via a primary cell and providing access to the primary cell to a user device, wherein the user device is configured to support dual connectivity such that it can simultaneously connect to the master distributed node and a secondary distributed node providing access to a secondary serving cell, the master distributed node, upon connection of the user device, becomes a serving master distributed node for the user device and provides access to the primary serving cell, the master distributed node comprises at least one processor and at least one memory for storing instructions, the instructions, when executed by the at least one processor, are sent to the master distributed node, at least, A master distributed node that receives measurement reports from user equipment relating to at least a non-serving master cell, and performs a lower-layer mobility dual connectivity handover decision in response to the measurement reports.

10. The received measurement report relates to at least the non-serving master cell and secondary cell, according to claim 9, for the master distributed node.

11. Following the handover decision, To generate cell change instructions that indicate changes to the primary serving cell and changes to the configuration of secondary cells, The cell change instruction is transmitted to the user device as part of a Layer 2 message. A master distributed node according to claim 9, further configured to do the following.

12. The master distributed node according to claim 11, wherein the cell change instruction further includes an instruction for a cell change for the secondary serving cell.

13. A message containing a configuration for performing at least non-serving master cells and secondary cells is forwarded to the user device, The message is transmitted to the user device as part of a wireless resource control reconfiguration message. A master distributed node according to claim 9, further configured to do the following.

14. The master distributed node according to claim 9, configured to receive from a central node controlling the master distributed nodes the configuration of a target primary cell and instructions for at least one secondary cell for which measurements are required; to generate measurement and connectivity configuration information for the indicated target primary cell and the at least one secondary cell; and to transmit the measurement and connectivity configuration information to the central node.

15. A central node for controlling a plurality of distributed nodes configured to support providing wireless coverage to user equipment via a primary cell, wherein the user equipment is configured to support dual connectivity by simultaneous connection to a serving master distributed node that supports providing wireless coverage via a primary serving cell and a serving secondary distributed node that supports providing wireless coverage via a secondary serving cell, and the central node, At least one processor, The system comprises at least one memory for storing instructions, and when an instruction is executed by the at least one processor, the central node receives at least, To determine at least one non-serving master cell to be prepared for lower-layer mobility, To generate information indicating the at least one determined non-serving master cell and transmit it to a secondary central node that controls a plurality of secondary distributed nodes configured to support providing wireless coverage to the user equipment via secondary cells, Receiving secondary cell measurement and connection configuration information for secondary cells associated with the at least one non-serving master cell. The central node that enables this.

16. The central node according to claim 15, configured to generate and transmit the aforementioned information as a secondary node correction signal.

17. The central node according to claim 15, configured to generate and transmit the aforementioned information as a secondary node addition request signal.

18. To enable the serving master distributed node to perform lower-layer mobility dual connectivity handover decisions for multiple primary cells and at least one secondary cell, generate measurement and connectivity configuration requests indicating multiple primary cells and at least one secondary cell for which measurement information is required, Sending the aforementioned measurement and connection configuration requests to the serving master distributed node, The measurement and connection configuration information is received from the serving master distributed node, To generate reconstruction information for the plurality of primary cells and the at least one secondary cell, The reconfiguration information is transmitted to the serving master distributed node. The central node according to claim 15, further configured to do the following.

19. Generating a measurement and connection configuration request that requests a measurement configuration to a serving master node, Sending the aforementioned measurement and connection configuration requests to the serving master distributed node, The measurement and connection configuration information is received from the serving master distributed node, To generate measurement and connection configuration information for multiple primary cells and at least one secondary cell, To generate reconstruction information for the plurality of primary cells and the at least one secondary cell, The reconfiguration information is transmitted to the serving master distributed node. The central node according to claim 15, further configured to do the following.

20. A system for providing a wireless access network that supports lower-layer mobility for user equipment configured for dual connectivity, A master central node according to any one of claims 15 to 19, A plurality of master distributed nodes according to any one of claims 9 to 14, which support providing wireless coverage via a primary cell, wherein the master central node controls the plurality of master distributed nodes, It comprises a secondary central node for controlling at least one secondary distributed node, The system wherein the at least one secondary distributed node supports providing wireless coverage via at least one secondary cell.

21. A method for accessing a wireless access network comprising a master central node and a plurality of master distributed nodes that support providing wireless coverage via a primary cell, wherein the master central node controls the plurality of master distributed nodes, a secondary central node and at least one secondary distributed node support providing wireless coverage via at least one secondary cell, the secondary central node controls the at least one secondary distributed node, and the user device is configured to support dual connectivity such that it can simultaneously connect to a primary distributed node that provides access to a primary serving cell and a secondary distributed node that provides access to a secondary serving cell, and the method is: To establish dual connectivity to the primary serving cell and the secondary serving cell, The master node receives configurations from the serving master distributed node to enable the serving master distributed node to perform lower-layer mobility dual connectivity handover decisions, including the ability to perform measurements and connectivity to at least the non-serving master cell and secondary cell. Performing at least a portion of the measurements configured above, The report related to the measurements performed above is sent to the serving master distributed node via a lower-layer message. Methods that include...

22. A method implemented in a distributed node for supporting wireless coverage via a primary cell and providing access to the primary cell to a user device, wherein the user device is configured to support dual connectivity such that it can simultaneously connect to a master distributed node and a secondary distributed node providing access to a secondary serving cell, the master distributed node becomes a serving master distributed node for the user device and provides access to the primary serving cell, and the method is, The user equipment receives measurement reports related to at least the non-serving master cell and secondary cell, In response to the aforementioned measurement report, a lower-layer mobility dual connectivity handover decision is made. Methods that include...

23. A method for controlling a plurality of distributed nodes configured to support providing wireless coverage to a user device via a primary cell, wherein the user device is configured to support dual connectivity by simultaneous connection to a serving master distributed node that supports providing wireless coverage via at least one primary serving cell and a serving secondary distributed node that supports providing wireless coverage via at least one secondary serving cell, and the method is: To determine at least one non-serving master cell to be prepared for lower-layer mobility, To generate information indicating at least one determined non-serving master cell and transmit it to a secondary central node that controls a plurality of secondary distributed nodes configured to support providing wireless coverage to the user equipment via secondary cells, Receiving secondary cell configuration information for a secondary cell related to the at least one non-serving master cell mentioned above. Methods that include...

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