Method and apparatus for switching serving cell

Abstract

This invention provides a method and apparatus for switching serving cells. The method includes: a secondary node sending a secondary node modification request message to a primary node, causing the primary node to switch serving cells and release bearers to be released according to the secondary node modification request message; and the secondary node receiving a secondary node modification confirmation message returned by the primary node in response to the secondary node modification request message. The method provided by this invention enables the switching of serving cells and the release of bearers to be released on the secondary node based on the secondary node modification request message when there are bearers to be released during serving cell switching, greatly improving signaling transmission efficiency and saving signaling resources.

Description

[0001] This application is a divisional application of the invention patent application with application number 201710681888.3 and invention title "Method and apparatus for switching serving cells". Technical Field

[0002] This invention relates to the field of wireless communication technology, and more specifically, to a method and apparatus for handing over a serving cell. Background Technology

[0003] To improve user throughput, LTE systems introduced the concept of dual connectivity, allowing a user to connect to two different base stations simultaneously. In NR (New Radio access) networks or 5G networks, the concept of dual connectivity is further expanded to include Multi-RATD Dual Connectivity (MR-DC), where a user can simultaneously access base stations supporting different access technologies, such as two base stations supporting LTE and NR respectively. In the following discussion, we use MN (Master Node) and SN (Secondary Node) to represent the two base stations accessed by the user, such as... Figure 1 As shown. Each node may use air interface access technologies such as LTE and NR. Each node can access the core network of a 5G system or the core network of a 4G / LTE system. In the above scenario, the following concepts are introduced:

[0004] ■MCG (Master Cell Group): The cell group where users access the MN. Within the MCG, one cell is the Primary Cell (PCell), and the rest are Secondary Cells (SCells). Changing the PCell triggers a random access procedure for the user. The first cell a user accesses on the MN is the PCell. If the link between the user and the PCell fails, the user will be unable to communicate with the MN (even if the SCell link is working). Changing the SCell may not trigger a random access procedure for the user.

[0005] ■SCG (Secondary Cell Group): The cell group where users access the SN. Within an SCG, one cell is the primary cell (PSCell), and the others are secondary cells (SCG SCells). Changing a PSCell triggers a random access procedure for the user. The first cell a user accesses the SN is the PSCell. If the link between the user and the PSCell fails, the user will be unable to communicate with the SN (even if the link to the SCG SCell is working). Changing an SCG SCell may not trigger a random access procedure.

[0006] For a detailed explanation of the above concepts, please refer to TS36.300 v14.2.0.

[0007] Under the MN and SN architecture, the user's radio bearer includes four types:

[0008] ■MCG Bearer: Data on this bearer is transmitted between the MN and the user. The protocol layer that processes data on this type of bearer is located on the MN.

[0009] ■MCG Split Bearer: The data of this bearer is transmitted to the user via MN and SN. However, the PDCP (packet data convergence protocol) layer that processes the data of this type of bearer is located on MN, while other protocol layers (RLC (Radio link control) / MAC (Medium Access Control) / PHY (Physical Layer)) will be on MN and SN to process the data of this type of bearer.

[0010] ■SCG bearer: The data of this bearer is transmitted between the SN and the user. The protocol layer that processes the data of this type of bearer is located at the SN.

[0011] ■SCG split bearer: The data of this bearer is transmitted to the user via MN and SN, but the PDCP layer that processes the data of this type of bearer is located on SN, while there are other protocol layers (RLC / MAC / PHY) on MN and SN that process the data of this type of bearer.

[0012] For a detailed explanation of the above concepts, please refer to TS37.340.

[0013] The concepts of community and carrying capacity mentioned above are all from the perspective of a single user.

[0014] Furthermore, in NR (New Radio Access) networks or 5G networks, to support network function virtualization and more efficient resource management and scheduling, base stations (e.g., gNBs) that provide wireless network interfaces to users (UEs) can be further divided into central units (CUs) and distributed units (DUs). A CU has at least Radio Resource Control (RRC) and Packet Data Convergence Protocol (PDCP) layers, and may also include Service Data Adaptation Protocol (SDAP). A DU has Radio Link Control (RLC), Media Access Control (MAC), and physical layers. The CU and DU share a standardized public interface, F1. The F1 interface is divided into a control plane (F1-C) and a user plane (F1-U). The F1-C transport network layer is based on IP transmission. To provide more reliable signaling transmission, the Stream Control Transmission Protocol (SCTP) is added on top of IP. The application layer protocol is F1AP. SCTP can provide reliable application layer message transmission. The F1-U's transport layer is UDP / IP (User Datagram Protocol / Internet Protocol), while GTP-U (GPRS Tunneling Protocol for the user plane) is used on top of UDP / IP to carry User Plane Protocol Data Units (PDUs). Figure 2 The structures of CU and DU are shown.

[0015] In the above description, if there is a user plane interface serving a user between two nodes (such as X2-U between MN and SN, F1-U between CU and DU, and X2-U between MN and DU), a tunnel will be established when transmitting user data between the two nodes. This tunnel will correspond to two addresses (address 1 and address 2). These two addresses are the addresses used by the two nodes to transmit data for this user. That is, the user's data is sent from address 1 to address 2 or from address 2 to address 1.

[0016] Combining the aforementioned multi-connection and CU-DU separation technologies, a user may connect to the network in the following ways: the user simultaneously accesses both the MN and the SN, where the SN includes a CU and at least one DU connected to that CU, such as... Figure 3As shown. In this scenario, the PSCell accessed by the user on the SN may change. This change could be due to poor quality on the current PSCell, excessive load on the current PSCell, or other reasons. Such changes may include, but are not limited to, the following:

[0017] ■ The PSCell is changed from the current PSCell to the SCG SCell that has been configured for the user and belongs to the same DU.

[0018] ■ The PSCell is changed from the current PSCell to a cell belonging to the same DU that is not configured for users.

[0019] ■ The PSCell changes from its current PSCell to a cell belonging to another DU (this other DU and the DU where the current PSCell is located are both connected to the same CU, i.e., belong to the same SN), such as Figure 4 As shown.

[0020] ■ The PSCell changes from its current PSCell to a cell belonging to another DU (this other DU and the DU where the current PSCell is located are both connected to different CUs, i.e., belong to different SNs), such as Figure 5 As shown.

[0021] When the aforementioned PSCell change occurs, according to the LTE system, it will trigger an SN modification process initiated by the SN node (in this process, the messages sent and received by the SN are actually sent and received by the CU):

[0022] ■ Step 1: The SN sends a secondary node modification request (SN modification required) message to the MN. This message contains SCG change indication information (SCG Change Indication: This information indicates that the PSCell has changed. In practice, this indication message may also indicate other information) and SCG configuration information (SCG-Config, such as the configuration of the user's serving cell on the SN, i.e., the SCG, which may include RLC configuration, MAC layer configuration, etc.).

[0023] ■Steps 2 & 3: These two steps are optional and will be triggered when the MN needs to provide the address for data forwarding and / or the encryption key for the new SN.

[0024] ■ Step 4: If the configuration change of PSCell is successfully completed, MN replies to SN with a secondary node modification confirmation message (SNmodification confirm).

[0025] The above process can be found in TS36.300 v14.2.0.

[0026] According to the existing mechanism, in step 1 above, the SCG change instruction information and the SCG configuration information (SCG-Config) must appear simultaneously. If there is information about releasing the bearer in step 1, the SCG change instruction information is not allowed to appear in step 1. That is, the existing mechanism does not support the simultaneous occurrence of PSCell change and bearer release. Summary of the Invention

[0027] The purpose of this invention is to at least solve one of the above-mentioned technical defects, particularly the technical defect that there are bearers to be released when switching serving cells.

[0028] According to one aspect, embodiments of the present invention provide a method for handing over a serving cell, comprising:

[0029] The secondary node sends a secondary node modification request message to the primary node, so that the primary node can switch the serving cell and release the bearer to be released according to the secondary node modification request message;

[0030] The secondary node receives a secondary node modification confirmation message returned by the primary node in response to the modification request message of the secondary node.

[0031] According to another aspect, embodiments of the present invention also provide a method for handing over a serving cell, comprising:

[0032] The primary node receives a secondary node modification request message sent by the secondary node, switches the serving cell and releases the bearer to be released according to the secondary node modification request message;

[0033] The master node returns a modification confirmation message to the slave node in response to the modification request message from the slave node.

[0034] According to another aspect, embodiments of the present invention also provide an apparatus for handing over a serving cell, comprising:

[0035] The first sending module is used for the secondary node to send a secondary node modification request message to the primary node, so that the primary node can switch the serving cell and release the bearer to be released according to the secondary node modification request message.

[0036] The first receiving module is used for the auxiliary node to receive the auxiliary node modification confirmation message returned by the master node in response to the auxiliary node modification request message.

[0037] According to another aspect, embodiments of the present invention also provide an apparatus for handing over a serving cell, comprising:

[0038] The second receiving module is used for the master node to receive the auxiliary node modification request message sent by the auxiliary node, switch the serving cell and release the bearer to be released according to the auxiliary node modification request message;

[0039] The second sending module is used for the master node to return a modification confirmation message to the slave node in response to the modification request message of the slave node.

[0040] The present invention provides a method for switching serving cells. A secondary node sends a secondary node modification request message to a primary node, enabling the primary node to switch serving cells and release bearers to be released based on the secondary node modification request message. This provides a prerequisite guarantee for releasing user bearers on the secondary node during subsequent serving cell switching based on the secondary node modification request message. The secondary node receives a secondary node modification confirmation message returned by the primary node in response to the secondary node modification request message. This enables the switching of serving cells and release of bearers to be released on the secondary node based on the secondary node modification request message when there are bearers to be released during serving cell switching, greatly improving signaling transmission efficiency and saving signaling resources.

[0041] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0042] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0043] Figure 1 This is a network structure diagram of multiple UE connections in the existing technology;

[0044] Figure 2 This is a structural diagram of the centralized unit and distributed unit of a base station in the existing technology;

[0045] Figure 3 A network structure diagram of a UE connecting to multiple connections, including centralized units and distributed units, in the existing technology;

[0046] Figure 4 This is a schematic diagram illustrating how the distribution unit for serving users is changed in existing technologies.

[0047] Figure 5 This is a schematic diagram illustrating how to change the service auxiliary node for users in existing technologies.

[0048] Figure 6 This is a flowchart of a method for switching serving cells according to the first embodiment of the present invention;

[0049] Figure 7 This is a flowchart of a method for switching serving cells according to a second embodiment of the present invention;

[0050] Figure 8 This is a signaling flowchart for changing a user's service distribution unit through a user context establishment process, as described in an embodiment of the present invention.

[0051] Figure 9 This is a signaling flowchart illustrating how a user's distribution unit configuration on the same secondary node is changed through a user context establishment process, as described in an embodiment of the present invention.

[0052] Figure 10 This is a signaling flowchart of the first method for modifying the PSCell of a user on a secondary node in an embodiment of the present invention.

[0053] Figure 11 This is a signaling flowchart for modifying the PSCell of a user on a secondary node in a second embodiment of the present invention.

[0054] Figure 12 This is a signaling flowchart for the third embodiment of the present invention that modifies the PSCell of the user on the distribution unit of the auxiliary node;

[0055] Figure 13 This is a signaling flowchart of auxiliary node modification triggered by an auxiliary node in an embodiment of the present invention;

[0056] Figure 14 This is a signaling flowchart illustrating user context establishment between a centralized unit and a distributed unit, according to an embodiment of the present invention.

[0057] Figure 15 This is a signaling flowchart of user context modification triggered by a centralized unit in an embodiment of the present invention;

[0058] Figure 16 The signaling flowchart (two steps) for user context modification triggered by the first distributed unit in this embodiment of the invention is shown below.

[0059] Figure 17 The signaling flowchart (three or four steps) for user context modification triggered by the second type of distributed unit in this embodiment of the invention.

[0060] Figure 18 This is a schematic diagram of the device for handing over serving cells according to the third embodiment of the present invention;

[0061] Figure 19 This is a schematic diagram of the device for handing over serving cells according to the fourth embodiment of the present invention. Detailed Implementation

[0062] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0063] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or wireless coupling. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.

[0064] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0065] Those skilled in the art will understand that the terms "terminal" and "terminal device" as used herein include both devices that receive wireless signals, devices that only possess wireless signal receiver capabilities without transmission capabilities, and devices with receiving and transmitting hardware, devices that have receiving and transmitting hardware capable of bidirectional communication over a bidirectional communication link. Such devices may include: cellular or other communication devices having a single-line display, a multi-line display, or a cellular or other communication device without a multi-line display; PCS (Personal Communications Service) that can combine voice, data processing, fax, and / or data communication capabilities; PDA (Personal Digital Assistant) that may include a radio frequency receiver, pager, Internet / intranet access, web browser, notepad, calendar, and / or GPS (Global Positioning System) receiver; and conventional laptop and / or handheld computers or other devices that have and / or include radio frequency receivers. As used herein, "terminal" or "terminal device" can be portable, transportable, installed in a means of transportation (air, sea, and / or land), or suitable and / or configured to operate locally, and / or in a distributed manner, operating in any other location on Earth and / or in space. "Terminal" or "terminal device" as used herein can also be a communication terminal, an internet access terminal, or a music / video playback terminal, such as a PDA, a MID (Mobile Internet Device), and / or a mobile phone with music / video playback capabilities, or a smart TV, set-top box, etc.

[0066] In a 5G network, when a user is simultaneously connected to both the MN and SN, and the SN comprises a CU and at least one DU connected to that CU, a change in the PSCell may cause the release of user bearers. For example, due to user mobility, the user's PSCell needs to be changed, such as from one DU (DU1) to another DU (DU2) connected to the same CU. Currently, this user is configured with one PSCell and multiple SCG SCells on DU1, but only one cell is suitable on DU2. Therefore, only one PSCell can be configured for this user on DU2. In other words, during this process, the cell serving the user changes from multiple cells on DU1 to one cell on DU2. This may necessitate the release of some bearers serving the user through the SN. This scenario represents a simultaneous PSCell change and bearer release. However, existing mechanisms do not support the simultaneous occurrence of PSCell changes and bearer releases. Furthermore, to support such scenarios, the CU and DU also need to perform user context establishment and modification processes. These processes need to consider the operations of establishing and modifying the serving cell context for the user, which is not addressed in existing discussions.

[0067] Furthermore, in a 5G network, a user may be connected to both the MN and the SN simultaneously, where the SN includes a CU and at least one DU connected to that CU. In this scenario, the user's PSCell may change, and the user bearer on the SN may be released. To support this situation, embodiments of the present invention provide a process for signaling interaction between the MN and SN, as well as a process for establishing and modifying user contexts between the CU and DU, as detailed below.

[0068] To address the technical deficiency in existing technologies where unreleased bearers exist during cell handover, the first embodiment of this invention provides a method for cell handover, the specific process of which is as follows: Figure 6 As shown, the process includes: Step 610, the secondary node sends a secondary node modification request message to the primary node, so that the primary node switches the serving cell and releases the bearer to be released according to the secondary node modification request message; Step 620, the secondary node receives a secondary node modification confirmation message returned by the primary node in response to the secondary node modification request message.

[0069] Preferably, the secondary node modification request message includes at least one of the following: information on the bearers to be released, indication information on changes to the secondary cell group SCG, first indication information, second indication information, third indication information, SCG configuration information, and information on the bearers not yet released.

[0070] Preferably, the information of the bearers to be released and the information of the bearers not released include at least one of the following: bearer identification information, bearer QoS parameters, bearer type information, tunnel address information for transmitting bearer data between two nodes, forwarding address of bearer uplink data, and forwarding address of bearer downlink data; SCG change indication information is used to indicate the primary cell PScell ​​for changing the SCG; SCG configuration information is configuration information related to the SCG configured for the UE generated by the secondary node; first indication information is used to instruct the primary node to trigger the sending of a secondary node modification request message to the secondary node; second indication information is used to instruct the primary node to prohibit sending SCG configuration information to the user terminal UE; third indication information is used to instruct the secondary node to prohibit updating SCG configuration information; the information of the bearers not released includes the information of each bearer not released and / or the information of the bearers not released by the primary cell group MCG split bearers, wherein the information of the bearers not released by the primary cell group MCG split bearers includes the bearer identification and the address information of the tunnel for transmitting bearer data on the secondary node side.

[0071] Preferably, after the step of the secondary node sending the secondary node modification requirement message to the primary node, the method further includes: the secondary node sending SCG configuration information to the UE.

[0072] Preferably, before the step of the secondary node receiving the secondary node modification confirmation message returned by the primary node in response to the secondary node modification request message, the method further includes: receiving the secondary node modification request message sent by the primary node; and sending the secondary node modification request confirmation message to the primary node in response to the secondary node modification request message.

[0073] Preferably, the secondary node modification request message includes at least one of the following: information on the newly added bearer, information on the bearer to be modified, information on the bearer to be released, encryption key information of the secondary node, indication information for SCG change, and information for configuring the SCG, wherein the information for configuring the SCG is information generated by the primary node requesting the UE to establish, modify, or release the SCG; the secondary node modification request confirmation message includes at least one of the following: information on the accepted newly added bearer, information on the accepted bearer to be modified, information on the accepted bearer to be released, SCG configuration information, and information on the unreleased MCG split bearer.

[0074] Preferably, before the step of the secondary node sending the secondary node modification requirement message to the primary node, the method further includes: the secondary node performing the corresponding UE context establishment or the corresponding UE context modification.

[0075] Preferably, the auxiliary node includes a centralized unit (CU) and at least one distributed unit (DU) connected to the CU. The steps for the auxiliary node to perform the corresponding UE context establishment include: sending a UE context establishment request message to the DU through the CU; and receiving a UE context establishment response message returned by the DU in response to the UE context establishment request message through the CU.

[0076] Preferably, the UE context establishment request message includes at least one of the following: cell list information, information on newly added cells sent by the CU, context information related to the UE bearer and / or identifier, and reason information for establishing the UE context; the UE context establishment response message includes at least one of the following: identifier information of unaccepted cells, context information related to the UE bearer and / or identifier, reason information for the DU returning the UE context establishment response message, and information on newly added cells sent by the DU; the cell list information includes at least one of the following: cell identifier, and cell measurement results; the information on newly added cells sent by the CU includes information on newly added cells already determined by the CU or information on candidate newly added cells already determined by the CU; the information on newly added cells already determined by the CU includes at least one of the following: cell list information, identifier information of one or more PCell cells, identifier information of one or more SCell cells, identifier information of one or more PSCell cells, and one or more SCG cells. The information includes: SCell cell identification information, cell measurement information; The information of the candidate new cells identified by the CU includes at least one of the following: candidate cell list information, identification information of one or more candidate PCell cells, identification information of one or more candidate SCell cells, identification information of one or more candidate PSCell cells, identification information of one or more candidate SCG SCell cells, and measurement information of the candidate new cells; The information of new cells sent by the DU includes at least one of the following: the identifier of the selected PCell cell, the identifier of one or more selected SCell cells, the identifier of the selected PSCell cell, and the identifier of one or more selected SCG cells. The SCell cell identifier; context information related to the UE bearer and / or identifier, including at least one of the following: user bearer information, user identifier information; reason information for establishing UE context and reason information for the DU returning the UE context establishment response message, including at least one of the following: cell overload, cell uplink overload, cell downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the UE in the cell, poor uplink or downlink signal quality or strength of the UE in the cell; whether the reason information for establishing UE context and the DU returning the UE context establishment response message are for each cell or for all cells.

[0077] Preferably, the auxiliary node includes a centralized unit (CU) and at least one distributed unit (DU) connected to the CU. The steps for the auxiliary node to perform the corresponding UE context modification include: sending a UE context modification request message to the DU through the CU; and receiving a UE context modification response message returned by the DU in response to the UE context modification request message through the CU.

[0078] Preferably, the auxiliary node includes a centralized unit (CU) and at least one distributed unit (DU) connected to the CU. The steps for the auxiliary node to perform corresponding UE context modification include: sending a UE context modification request message to the CU through the DU; and receiving a UE context modification confirmation message returned by the CU in response to the UE context modification request message through the DU.

[0079] Preferably, the auxiliary node includes a centralized unit (CU) and at least one distributed unit (DU) connected to the CU. The step of the auxiliary node performing the corresponding UE context modification includes:

[0080] Send a UE context modification request message to the CU via the DU;

[0081] Send a UE context modification request message to the DU via the CU;

[0082] The CU receives the UE context modification response message returned by the DU in response to the UE context modification request message.

[0083] Preferably, after the step of receiving the UE context modification response message returned by the DU for the UE context modification request message through the CU, the method further includes:

[0084] The DU receives the UE context modification confirmation message returned by the CU.

[0085] The first embodiment of the present invention provides a method for switching serving cells. Compared with the prior art, the secondary node sends a secondary node modification request message to the primary node, so that the primary node switches serving cells and releases the bearers to be released according to the secondary node modification request message. This provides a prerequisite guarantee for releasing user bearers on the secondary node when switching serving cells according to the secondary node modification request message. The secondary node receives a secondary node modification confirmation message returned by the primary node in response to the secondary node modification request message. This realizes that when there are bearers to be released during the switching of serving cells, the serving cell is switched and the bearers to be released on the secondary node are released according to the secondary node modification request message, which greatly improves the signaling transmission efficiency and saves signaling resources.

[0086] Furthermore, to address the technical deficiency in existing technologies where unreleased bearers exist during cell handover, the second embodiment of this invention also provides a method for cell handover, the specific process of which is as follows: Figure 7As shown, the process includes: Step 710, the primary node receives the secondary node modification request message sent by the secondary node, switches the serving cell and releases the bearer to be released according to the secondary node modification request message; Step 720, the primary node returns a secondary node modification confirmation message to the secondary node in response to the secondary node modification request message.

[0087] The second embodiment of the present invention provides a method for switching serving cells, which enables the master node to switch serving cells and release the bearers to be released on the SN according to the modification request message received from the secondary node when switching serving cells and there are bearers to be released, which greatly improves the signaling transmission efficiency and saves signaling resources.

[0088] The embodiments of the present invention described above will now be presented in a comprehensive and detailed manner, depending on the specific circumstances:

[0089] The main problem addressed by the above embodiments of the present invention is that when a user is simultaneously connected to both the MN and SN, the primary cell PSCell of the user UE changes, and some bearers served by the SN need to be released. The primary cell PSCell here refers to the special cell PSCell used below. This change in PSCell can occur within the same DU or between different DUs. When it occurs between different DUs, the address of the tunnel (the tunnel between the MN and DU) used to send data for MCG split bearers will change. The signaling names in the following signaling flow are merely examples and other names can be used. The following is a unified description of some general information used in the description below, as follows:

[0090] ■ The information carried, which may be a newly added bearer, a bearer to be modified, a bearer to be released, an accepted newly added bearer, an accepted bearer to be modified, an accepted bearer to be released, a rejected newly added bearer, a rejected bearer to be modified, or a rejected bearer to be released, includes one or more of the following information:

[0091] ■The identification information it carries.

[0092] ■ The QoS parameters carried, such as QoS Class Identifier, 5G QoS Indicator, Allocation and Retention Priority, Non-standardized QoS Flow descriptor, etc. (For details, please refer to protocol TS36.423 and protocol TS38.423).

[0093] ■ Bearer type information, such as MCG bearer, MCG split bearer, SCG bearer, SCG split bearer.

[0094] ■ The address information of the tunnel used to transmit data between two nodes, such as GTP tunnel endpoint information (see protocol TS36.423), which includes transport layer address information (see protocols TS36.424, TS36.414) and / or GTP tunnel endpoint identifier (see protocol TS29.281). These two nodes can be MN and SN, or a centralized unit of MN and SN, or a distributed unit of MN and SN, or a centralized unit and a distributed unit. The address information is the address information of one side of the node, such as MN, SN, a centralized unit of SN, a distributed unit of SN, a centralized unit of a base station, a distributed unit of a base station, etc.

[0095] ■ The forwarding address (UL forwarding GTP Tunnel Endpoint) of the uplink data carried, such as the address on the node side that sends the information carried.

[0096] ■ The forwarding address (DL forwarding GTP Tunnel Endpoint) of the downlink data carried, such as the address on the node side that sends the bearer information.

[0097] The SCG Change Indication can indicate a change in the PSCell or other information, such as PDCP Count Wrap Around.

[0098] SCG configuration information (SCG-Config) is generated by the SN and contains relevant configuration information about the SCG configured for the user, such as the configuration of PSCell, SCG SCell, RLC configuration, MAC layer configuration, etc.

[0099] The message used to configure the SCG (SCG-ConfigInfo) is generated by the MN to request the user to create, modify, and release the SCG. The MN also provides some auxiliary information in this message to help the SN generate the SCG-Config.

[0100] To simplify the following textual description, unless otherwise specified, the specific content of the above information will be referred to as the information carried, the instruction information for SCG change, and the SCG configuration information (SCG-Config).

[0101] First, here is an example of the relevant signaling flow:

[0102] 1) In this embodiment of the invention, the PSCell and the new PSCell belong to different DUs (CU-triggered UE context establishment procedures), such as... Figure 8 As shown.

[0103] 2) In this embodiment of the invention, the PSCell and the new PSCell belong to the same DU (CU-triggered UE context establishment process), such as... Figure 9 As shown.

[0104] 3) In this embodiment of the invention, the PSCell and the new PSCell belong to the same DU (CU-triggered UE context modification process), such as... Figure 10 As shown.

[0105] 4) In this embodiment of the invention, the PSCell and the new PSCell belong to the same DU (DU-triggered UE context modification process), such as... Figure 11 As shown.

[0106] 5) The signaling flowchart of the modified user's PSCell on the distribution unit of the secondary node in this embodiment of the invention is as follows: Figure 12 As shown.

[0107] The above signaling flow can be divided into two parts: A) the signaling flow between MN and SN (or centralized units in SN); B) the signaling flow between centralized units and distributed units in SN; these two parts will be explained below:

[0108] A. Signaling flow between MN and SN

[0109] Figure 13 It shows Figures 8 to 12 Signaling flow between MN and SN. The signaling flow between MN and SN described below applies not only to... Figures 8 to 12 The signaling flow shown also applies to other situations, such as situations where secondary node modifications are triggered by secondary nodes.

[0110] Step 1: The secondary node (or secondary node-centralized unit) sends a secondary node modification request (SNmodification required) message to the primary node. This message contains one or more of the following information:

[0111] ■The information to be released;

[0112] ■Instructions for changes to SCG, indicating changes to PSCell;

[0113] ■ New instruction information indicates that the master node needs to trigger step 2;

[0114] ■ No instruction information needs to be sent to the user regarding SCG configuration information (SCG-Config);

[0115] ■ Indication that no update of SCG configuration information (SCG-Config) is required;

[0116] ■SCG configuration information (SCG-Config);

[0117] ■ Information on unreleased bearers, which can be about each unreleased bearer or about a portion of unreleased bearers (such as unreleased MCG split bearers). If the user is connected to both MN and SN (or the SN's distribution unit), the address information in this information refers to the address information on the SN side, the SN's central unit side, or the SN's distribution unit side.

[0118] Step 2: The master node sends a secondary node modification request (SNmodification request) message to the secondary node (or secondary node-centralized unit). This message includes one or more of the following information:

[0119] ■ Newly added information;

[0120] ■ The information to be modified;

[0121] ■The information to be released;

[0122] ■ The encryption key information of the auxiliary node;

[0123] ■Indication information indicating SCG change;

[0124] ■ Messages used to configure SCG (SCG-ConfigInfo).

[0125] Step 3: The secondary node (or secondary node-centralized unit) sends a secondary node modification request acknowledgement (SNmodification request acknowledge) message to the primary node. This message contains one or more of the following information:

[0126] ■ The newly accepted information carried;

[0127] ■ The accepted information to be modified;

[0128] ■ The information carried and accepted for release;

[0129] ■SCG configuration information (SCG-Config);

[0130] ■ No instruction information needs to be sent to the user regarding SCG configuration information (SCG-Config);

[0131] Step 4: The master node sends a slave node modification confirmation (SNmodification confirm) message to the slave node (or slave node-centralized unit). This message may include a message for configuring the SCG (SCG-ConfigInfo).

[0132] It should be noted that steps 2 and 3 above are optional. The condition that triggers step 2 may be any of the following:

[0133] ■ Step 1 includes an instruction to trigger Step 2;

[0134] ■ Step 1 includes the following information:

[0135] ■The information to be released, and

[0136] ■One or more of the following information:

[0137] ◆Indication message for SCG change, indicating a change in PSCell.

[0138] ◆SCG Configuration Information (SCG-Config)

[0139] ◆Information on unreleased bearers, which can be about each unreleased bearer or about a portion of unreleased bearers (such as unreleased MCG split bearers). If the user is connected to both MN and SN (or the SN's distribution unit), the address information in this information refers to the address information on the SN side, the SN's central unit side, or the SN's distribution unit side.

[0140] The above process has the following detailed embodiments (the possible triggering conditions for these detailed embodiments are: when the SN determines that the user's PSCell has changed and there is a bearer that needs to be released, the change of PSCell occurs within the same distribution unit or different distribution units; other triggering conditions are not excluded).

[0141] The following is a detailed description of each embodiment.

[0142] Specifically, the detailed process of Detailed Implementation Example 1 (including two steps, namely step 1 and step 4, and MN sending SCG-Config to User Equipment UE) is as follows:

[0143] Step 1: The secondary node (or secondary node-centralized unit) sends a secondary node modification request (SNmodification required) message to the primary node. This message contains the following information:

[0144] ■The information to be released;

[0145] ■Optional, SCG change indication information, which indicates a change in PSCell;

[0146] ■SCG configuration information (SCG-Config);

[0147] ■Optional, the information carried by the unreleased MCG split includes at least the following:

[0148] ■The logo it carries;

[0149] ■ The address information of the tunnel used to transmit the data on the SN side or the SN distribution unit side.

[0150] In the above information, the indication information for SCG change is optional. It can implicitly indicate that the user's PSCell needs to be changed by including information on unreleased MCG split bearers and / or SCG configuration information (SCG-Config) in step 1.

[0151] Steps 2 / 3: These two steps are unnecessary.

[0152] Step 4: The master node sends a secondary node modification confirmation (SNmodification confirm) message to the secondary node (or secondary node-centralized unit).

[0153] Then, the master node sends the SCG configuration information (SCG-Config) received in step 1 to the user. This step can be done after step 1.

[0154] Specifically, the detailed process of Detailed Embodiment Two (including two steps, namely step 1 and step 4, and the SN sending SCG-Config to the User Equipment UE) is as follows:

[0155] Step 1: The secondary node (or secondary node-centralized unit) sends a secondary node modification request (SNmodification required) message to the primary node. This message from the secondary node contains the following information:

[0156] ■The information to be released;

[0157] ■Optional, SCG change indication information, which indicates a change in PSCell;

[0158] ■Optional, the information carried by the unreleased MCG split includes at least the following:

[0159] ◆The logo it carries;

[0160] ◆The address information of the tunnel used to transmit the data on the SN side or the SN distribution unit side.

[0161] In the above information, the indication of SCG change is optional. It can implicitly indicate the change of the user's PSCell by including information about the unreleased MCG split bearer in step 1.

[0162] Steps 2 / 3: These two steps are unnecessary.

[0163] Step 4: The master node sends a secondary node modification confirmation (SNmodification confirm) message to the secondary node (or secondary node-centralized unit).

[0164] Specifically, before step 1 or between steps 1 and 4, the auxiliary node generates SCG configuration information (SCG-Config), and sends it to the user after step 1.

[0165] Specifically, the detailed process of Detailed Embodiment Three (including four steps, namely steps 1 to 4, where there is no SCG configuration information (SCG-Config) in step 1) is as follows:

[0166] Step 1: The secondary node (or secondary node-centralized unit) sends a secondary node modification request (SNmodification required) message to the primary node. This message contains the following information:

[0167] ■The information to be released;

[0168] ■Optional, SCG change indication information, which indicates a change in PSCell, or, optional, new indication information, which indicates that the master node needs to trigger step 2;

[0169] ■Optional, the information carried by the unreleased MCG split includes at least the following:

[0170] ■The logo it carries;

[0171] ■ The address information of the tunnel used to transmit the data on the SN side or the SN distribution unit side.

[0172] In the above information, the indication information for SCG change is optional. It can implicitly indicate a change in the user's PSCell by including information about unreleased MCG split bearers in step 1, or implicitly indicate that the master node needs to trigger step 2.

[0173] Step 2: The master node sends a secondary node modification request (SNmodification request) message to the secondary node (or secondary node-centralized unit). This message includes one or more of the following information:

[0174] ■ Newly added information;

[0175] ■ The information of the bearer to be modified may include the bearer information after the bearer type is modified for the bearer to be released in step 1;

[0176] ■The information to be released;

[0177] ■ The encryption key information of the auxiliary node;

[0178] ■Indication information indicating SCG change;

[0179] ■ Messages used to configure SCG (SCG-ConfigInfo).

[0180] Step 3: The secondary node (or secondary node-centralized unit) sends a secondary node modification request acknowledgement (SNmodification request acknowledge) message to the primary node. This message contains one or more of the following information:

[0181] ■SCG configuration information (SCG-Config);

[0182] ■Optional, the information carried by the unreleased MCG split includes at least the following:

[0183] ■The logo it carries;

[0184] ■ The address information of the tunnel used to transmit the data on the SN side or the SN distribution unit side.

[0185] Step 4: The master node sends a secondary node modification confirmation (SNmodification confirm) message to the secondary node (or secondary node-centralized unit).

[0186] In the above steps, the SCG configuration information (SCG-Config) can be sent to the user by either the secondary node or the primary node. If sent by the secondary node, one implementation is that after step 1, the secondary node sends the SCG configuration information (SCG-Config) (such as the SCG configuration information (SCG-Config) generated after step 2) to the user, then step 3 does not need to include the SCG configuration information (SCG-Config). Another implementation is that step 3 includes the SCG configuration information (SCG-Config), but this configuration information is sent by the secondary node, and the secondary node adds an indication to the secondary node modification request acknowledgement message in step 1 (SNmodification required) or step 3 (SN modification request acknowledgement) message, indicating that the primary node does not need to send the SCG configuration information (SCG-Config). If sent by the primary node, one implementation is that step 3 includes the SCG configuration information (SCG-Config), and the primary node sends the SCG configuration information (SCG-Config) received in step 3.

[0187] Specifically, the detailed process of Detailed Embodiment Four (including four steps, namely steps 1 to 4, where SCG configuration information (SCG-Config) is included in step 1 and SCG-Config is updated in step 3) is as follows:

[0188] Step 1: The secondary node (or secondary node-centralized unit) sends a secondary node modification request (SNmodification required) message to the primary node. This message contains the following information:

[0189] ■The information to be released;

[0190] ■Optional, SCG change indication information, which indicates a change in PSCell, or, optional, new indication information, which indicates that the master node needs to trigger step 2;

[0191] ■SCG configuration information (SCG-Config);

[0192] ■Optional, the information carried by the unreleased MCG split includes at least the following:

[0193] ■The logo it carries;

[0194] ■ The address information of the tunnel used to transmit the data on the SN side or the SN distribution unit side.

[0195] In the above information, the indication information for SCG change is optional. It can implicitly indicate that the user's PSCell needs to be changed by including information on unreleased MCG split bearers and / or SCG configuration information (SCG-Config) in step 1, or implicitly indicate that the master node needs to trigger step 2.

[0196] Step 2: The master node sends a secondary node modification request (SNmodification request) message to the secondary node (or secondary node-centralized unit). This message includes one or more of the following information:

[0197] ■ Newly added information;

[0198] ■ The information of the bearer to be modified may include the bearer information after the bearer type is modified for the bearer to be released in step 1;

[0199] ■The information to be released;

[0200] ■ The encryption key information of the auxiliary node;

[0201] ■Indication information indicating SCG change;

[0202] ■ Messages used to configure SCG (SCG-ConfigInfo).

[0203] Step 3: The secondary node (or secondary node-centralized unit) sends a secondary node modification request acknowledgement (SNmodification request acknowledge) message to the primary node. This message contains one or more of the following information:

[0204] ■SCG configuration information (SCG-Config);

[0205] ■Optional, the information carried by the unreleased MCG split includes at least the following:

[0206] ■The logo it carries;

[0207] The address information of the tunnel used to transmit the data on the SN side or the SN's distribution unit side. Step 4: The master node sends a slave node modification confirm message to the slave node (or slave node-centralized unit).

[0208] In the above steps, the SCG configuration information (SCG-Config) can be sent to the user by either the secondary node or the primary node. If sent by the secondary node, one implementation is that the secondary node sends the SCG configuration information (SCG-Config) generated after step 2, and step 3 does not need to include the SCG configuration information (SCG-Config). Another implementation is that the secondary node first sends the SCG configuration information (SCG-Config) from step 1 to the user, and then sends the SCG configuration information (SCG-Config) generated after step 2 to the user. Yet another implementation is that step 3 includes the SCG configuration information (SCG-Config), but this configuration information is sent by the secondary node after step 3, and the secondary node adds an indication to the secondary node modification request (SN modification require) message in step 1 or the secondary node modification request acknowledge (SN modification request acknowledge) message in step 3, indicating that the primary node does not need to send the SCG configuration information (SCG-Config). If sent by the primary node, one implementation is that step 3 includes the SCG configuration information (SCG-Config), and the primary node sends the SCG configuration information (SCG-Config) received in step 3. Another implementation is that the master node first sends the SCG configuration information (SCG-Config) from step 1, and then sends the SCG configuration information (SCG-Config) received in step 3. Alternatively, the master node and slave node can send the information together. In one implementation, the master node sends the SCG configuration information (SCG-Config) from step 1, and the slave node sends the SCG configuration information (SCG-Config) generated after step 2. In another implementation, the slave node sends the SCG configuration information (SCG-Config) from step 1, and the master node sends the SCG configuration information (SCG-Config) generated after step 2; in this case, step 3 will include the SCG configuration information (SCG-Config).

[0209] Specifically, the detailed process of Detailed Embodiment Five (including four steps, namely steps 1 to 4, where SCG configuration information (SCG-Config) is present in step 1 and SCG-Config is not updated in step 3) is as follows:

[0210] Step 1: The secondary node (or secondary node-centralized unit) sends a secondary node modification requirement (SNmodification require) message to the primary node. This message contains the following information:

[0211] ■The information to be released;

[0212] ■Optional, SCG change indication information, which indicates a change in PSCell, or, optional, new indication information, which indicates that the master node needs to trigger step 2;

[0213] ■SCG configuration information (SCG-Config);

[0214] ■Optional, the information carried by the unreleased MCG split includes at least the following:

[0215] ■The logo it carries;

[0216] ■ The address information of the tunnel used to transmit the data on the SN side or the SN distribution unit side.

[0217] In the above information, the indication information for SCG change is optional. It can implicitly indicate that the user's PSCell needs to be changed by including information on unreleased MCG split bearers and / or SCG configuration information (SCG-Config) in step 1, or implicitly indicate that the master node needs to trigger step 2.

[0218] Step 2: The master node sends a secondary node modification request (SNmodification request) message to the secondary node (or secondary node-centralized unit). This message includes one or more of the following information:

[0219] ■ Newly added information;

[0220] ■ The information of the bearer to be modified may include the bearer information after the bearer type is modified for the bearer to be released in step 1;

[0221] ■The information to be released;

[0222] ■ The encryption key information of the auxiliary node;

[0223] ■Indication information indicating SCG change;

[0224] ■ Messages used to configure SCG (SCG-ConfigInfo).

[0225] Step 3: The auxiliary node (or auxiliary node-centralized unit) sends an auxiliary node modification request acknowledgement message to the master node. This message does not contain SCG configuration information (SCG-Config), but optionally, it may contain information about unreleased MCG split bearers.

[0226] Step 4: The master node sends a secondary node modification confirmation (SNmodification confirm) message to the secondary node (or secondary node-centralized unit).

[0227] In the above steps, the SCG configuration information (SCG-Config) can be sent to the user by either the secondary node or the primary node. If sent by the secondary node, one implementation is that the secondary node may send it after steps 1 / 2 / 3 / 4. Optionally, the secondary node may instruct the primary node in step 1 or step 3 that it does not need to send the SCG configuration information (SCG-Config) to the user. Another implementation is that step 3 includes the SCG configuration information (SCG-Config), but this configuration information is sent by the secondary node after step 3, and the secondary node adds an indication to its SN modification request acknowledge message in step 3, indicating that the primary node does not need to send the SCG configuration information (SCG-Config). If sent by the primary node, one implementation is that the primary node may send the SCG configuration information (SCG-Config) received in step 1 after steps 1 / 2 / 3 / 4.

[0228] B. Signaling flow between centralized and distributed units

[0229] This signaling process includes a user context establishment process and a user context modification process. These two processes will be conducted separately... Figures 8 to 12 While these methods are used in practice, the user context creation and modification processes described below are not limited to this. Figures 8 to 12 It can be used in processes, and can also be used in other situations where it is necessary to establish and modify user context between centralized nodes and distributed nodes.

[0230] B-1. User Context Establishment Process

[0231] The process consists of two steps, such as Figure 14 As shown:

[0232] Step 1: The centralized unit sends a UE Context Setup Request message to the distributed unit. This message will contain one or more of the following information:

[0233] ■ Cell list information, which contains one or more cells, and includes one or more of the following information:

[0234] ■Community signage;

[0235] ■ Measurement results of the cell, such as signal quality and signal strength.

[0236] ■ Information about newly added cells sent by the CU. These newly added cells can be either already identified cells in the centralized unit or candidate cells. This information includes one or more of the following:

[0237] ■ Community list information, containing the identifiers of one or more communities;

[0238] ■ Identification information for one or more PCell cells;

[0239] ■ Identification information for one or more SCell cells;

[0240] ■ Identification information for one or more PSCell cells;

[0241] ■ Identification information for one or more SCG SCell cells;

[0242] ■ Measurement information of the cell, such as signal quality and signal strength.

[0243] ■ Context related to user bearer and / or identification, such as user bearer information, user identification information (such as the ID used by the user on the interface between the central unit and the distributed unit, for example, CU UE F1AP ID, which may be newly assigned by the CU, or already assigned to the user by the CU, or both).

[0244] ■ The reason for establishing the user context can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, poor uplink or downlink signal quality or strength of the user in the cell, etc.

[0245] Step 2: Based on its own access control criteria, the distributed unit will decide whether to accept the request from Step 1, and then reply to the centralized unit with a UE Context Setup Response message. This message will contain one or more of the following information:

[0246] ■ Information about newly added cells sent by the DU, which may include one or more of the following:

[0247] ■Identification of the selected PCell cell;

[0248] ■ Identifier of one or more selected SCell cells;

[0249] ■Identification of the selected PSCell cell;

[0250] ■Identifier of one or more selected SCG SCell cells.

[0251] ■ The identification information of unaccepted cells indicates that the cell is not suitable for being assigned to the user;

[0252] ■ Context related to the user bearer, such as information about the user bearer;

[0253] ■ The reason why the distribution unit responds as described above can be specific to each cell or to all cells. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, etc.

[0254] The distribution unit establishes the user's context according to the determined cell. Alternatively, if the distribution unit can accept the cell configuration information in the request message from step 1, the distribution unit may omit the selected cell information from the UE Context Setup Response message it replies with in step 2.

[0255] Depending on who decides on the user's cell configuration, the information included in the above two steps will differ. Specific implementation methods are shown below:

[0256] a. The centralized unit determines the user's cell configuration.

[0257] The UE Context Setup Request message in Step 1 contains one or more of the following:

[0258] ■ Information about newly added cells sent by the CU, which includes one or more of the following:

[0259] ■Identification information for the PCell community;

[0260] ■ Identification information for one or more SCell cells;

[0261] ■Identification information for the PSCell cell;

[0262] ■ Identification information for one or more SCG SCell cells;

[0263] ■ Measurement information for the aforementioned residential area.

[0264] ■ Context related to user bearer and / or identification, such as the user bearer message, user identification information (such as the ID used by the user on the interface between the central unit and the distributed unit, for example, CU UE F1AP ID, which may be newly assigned by the CU, or already assigned to the user by the CU, or both).

[0265] ■ The reason for establishing the user context can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, poor uplink or downlink signal quality or strength of the user in the cell, etc.

[0266] The UE Context Setup Response message in step 2 may contain one or more of the following:

[0267] ■ The identification information of unaccepted cells indicates that the cell is not suitable for being assigned to the user;

[0268] ■ Context related to the user bearer, such as information about the user bearer;

[0269] ■ The reason why the distribution unit responds as described above can be specific to each cell or to all cells. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, etc.

[0270] Additionally, if the distribution unit can accept the cell configuration information in the request message of step 1, the distribution unit may omit the aforementioned cell-related information (i.e., the identification information of the unaccepted cell) and / or other information (i.e., the context related to the user bearer, and the reason why the distribution unit made the above response) in the UE Context Setup Response message replied in step 2.

[0271] b. The distribution unit determines the user's cell configuration, while the centralized unit only provides a cell list.

[0272] The UE Context Setup Request message in Step 1 contains one or more of the following:

[0273] ■ Cell list information, which contains one or more cells, and includes one or more of the following information:

[0274] ■ Community signage;

[0275] ■ Measurement information of the cell, such as signal quality and signal strength.

[0276] ■ Context related to user bearer and / or identification, such as the user bearer message, user identification information (such as the ID used by the user on the interface between the central unit and the distributed unit, for example, CU UE F1AP ID, which may be newly assigned by the CU, or already assigned to the user by the CU, or both).

[0277] ■ The reason for establishing the user context can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, poor uplink or downlink signal quality or strength of the user in the cell, etc.

[0278] The UE Context Setup Response message in step 2 may contain one or more of the following:

[0279] ■ Information about newly added cells sent by the DU, which includes one or more of the following:

[0280] ■Identification information for the PCell community;

[0281] ■ Identification information for one or more SCell cells;

[0282] ■Identification information for the PSCell cell;

[0283] ■ Identification information for one or more SCG SCell cells.

[0284] ■ Context related to the user bearer, such as information about the user bearer;

[0285] ■ The reason why the distribution unit responds as described above can be specific to each cell or to all cells. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, etc.

[0286] The cells included in step 2 above can be cells selected from the cell list given in step 1, or cells not in the cell list given in step 1.

[0287] c. The distribution unit determines the user's cell configuration, while the centralized unit provides a list of candidate cells.

[0288] The UE Context Setup Request message in Step 1 contains one or more of the following information:

[0289] ■ Information on newly added candidate cells sent by the CU, which includes one or more of the following:

[0290] ■ List of candidate residential communities, including the identifiers of one or more communities;

[0291] ■ Identification information of one or more alternative PCell cells;

[0292] ■ Identification information for one or more candidate SCell cells;

[0293] ■ Identification information for one or more alternative PSCell cells;

[0294] ■ Identification information for one or more alternative SCG SCell cells;

[0295] ■ Measurement information of the above-mentioned cells, such as signal quality and signal strength.

[0296] ■ Context related to user bearer and / or identification, such as the user bearer message, user identification information (such as the ID used by the user on the interface between the central unit and the distributed unit, for example, CU UE F1AP ID, which may be newly assigned by the CU, or already assigned to the user by the CU, or both).

[0297] ■ The reason for establishing the user context can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, poor uplink or downlink signal quality or strength of the user in the cell, etc.

[0298] The UE Context Setup Response message in step 2 may contain one or more of the following:

[0299] ■ Information about newly added cells sent by the DU, which includes one or more of the following:

[0300] ■Identification information for the PCell community;

[0301] ■ Identification information for one or more SCell cells;

[0302] ■Identification information for the PSCell cell;

[0303] ■ Identification information for one or more SCG SCell cells.

[0304] ■ The identification information of unaccepted cells indicates that the cell is not suitable for being assigned to the user;

[0305] ■ Context related to the user bearer, such as information about the user bearer;

[0306] ■ The reason why the distribution unit responds as described above can be specific to each cell or to all cells. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, etc.

[0307] The cells included in step 2 above can be selected from the candidate cells given in step 1, or they can be cells not given in step 1. Furthermore, if the distribution unit can accept the cell configuration information in the request message of step 1, the distribution unit may omit the aforementioned cell-related information (i.e., information on newly added cells sent by the DU, identification information of unaccepted cells) and / or other information (i.e., context related to the user bearer, and information explaining the reason for the distribution unit's response) in the UE ContextSetup Response message replied in step 2.

[0308] B-2. User context modification process, which can be triggered by a centralized unit or a distributed unit.

[0309] a. The cell configuration modification process triggered by the centralized unit includes two steps, such as... Figure 15 As shown:

[0310] Step 1: The centralized unit sends a UE Context ModifiedRequest message to the distributed unit. This message will contain one or more of the following information:

[0311] ■ Cell list information, which contains one or more cells, and includes one or more of the following information:

[0312] ■Community signage;

[0313] ■ Measurement results of the cell, such as signal quality and signal strength.

[0314] ■ Information on newly added serving cells sent by the CU. The newly added cell can be a newly added cell already determined by the centralized unit, or it can be a candidate newly added cell, and includes one or more of the following information:

[0315] ■ Community list information, containing the identifiers of one or more communities;

[0316] ■ Identification information for one or more PCell cells;

[0317] ■ Identification information for one or more SCell cells;

[0318] ■ Identification information for one or more PSCell cells;

[0319] ■ Identification information for one or more SCG SCell cells;

[0320] ■ Measurement information of the above-mentioned cells, such as signal quality and signal strength.

[0321] ■ The information of the serving cell to be modified includes one or more of the following:

[0322] ■ The identifier for the PCell cell to be modified;

[0323] ■ The identifier for the SCell cell to be modified;

[0324] ■ The identifier of the PSCell cell to be modified;

[0325] ■ The identifier for the SCG SCell cell needs to be modified;

[0326] ■Identifiers of cells whose cell types have changed, indicating the cell type before and after the modification: such as the identifier of a cell that changes from PCcell to SCell, the identifier of a cell that changes from SCell to PCell, the identifier of a cell that changes from PSCell to SCG SCell, and the identifier of a cell that changes from SCG SCell to PSCell.

[0327] ■ Measurement information of the above-mentioned cells, such as signal quality and signal strength.

[0328] ■ Information about the service areas to be released, such as the area identifiers of the areas to be released;

[0329] ■ Context related to user bearer and / or identification, such as the user bearer message, user identification information (such as the ID used by the user on the interface between the central unit and the distributed unit, for example, CU UE F1AP ID, which may be newly assigned by the CU, or already assigned to the user by the CU, or both).

[0330] ■ The reason for modifying the user context can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, poor signal quality or strength of the load-balanced user in the cell, poor uplink or downlink signal quality or strength of the user in the cell, etc.

[0331] Step 2: The distributed unit sends a UE Context ModifiedResponse message to the centralized unit. This message may contain one or more of the following information:

[0332] ■ Information about newly added cells sent by the DU, which includes one or more of the following:

[0333] ■ The cell identifier of the newly added cell accepted, or the cell identifier of the newly added cell selected by the distribution unit. Optionally, it indicates the type of the newly added cell, such as PCell, SCell, PSCell, SCG SCell;

[0334] ■The signage for newly added residential communities that were not accepted.

[0335] ■ Information about the community to be modified, which includes one or more of the following:

[0336] ■ Accepted community signage to be modified;

[0337] ■ The community signage of the community that has not been accepted and is awaiting modification.

[0338] ■Information about the cells to be released, which includes one or more of the following:

[0339] ■Identification of the communities to be released;

[0340] ■Identification of communities awaiting release but not yet accepted.

[0341] ■ Context related to the user bearer, such as information about the user bearer;

[0342] ■ The reason for the above response can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, poor signal quality or strength of the load-balanced user in the cell, poor uplink or downlink signal quality or strength of the user in the cell, etc.

[0343] The newly accepted cell in step 2 can be obtained from the cell list information included in step 1 or the newly added serving cell, or it can be another cell. The distribution unit modifies the user's context according to the information in step 2. In addition, if the distribution unit can accept the cell configuration content in the request message in step 1, the distribution unit may omit the aforementioned cell-related information (i.e., the information of the newly added cell sent by the DU, the information of the cell to be modified, and the information of the cell to be released) and / or other information (i.e., the context related to the user bearer, and the reason information for the distribution unit to make the above response) in the UE Context Modification Response message replied in step 2.

[0344] b. The cell configuration modification process triggered by the distribution unit includes two steps, such as... Figure 16 As shown:

[0345] Step 1: The distributed unit sends a UE Context ModifiedRequired message to the centralized unit. This message will contain one or more of the following information:

[0346] ■ The information of the serving cell to be modified includes one or more of the following:

[0347] ■ The identifier for the PCell cell to be modified;

[0348] ■ The identifier for the SCell cell to be modified;

[0349] ■ The identifier of the PSCell cell to be modified;

[0350] ■ The identifier for the SCG SCell cell needs to be modified;

[0351] ■Identifiers of cells whose cell types have changed, indicating the cell type before and after the modification: such as the identifier of a cell that changes from PCcell to SCell, the identifier of a cell that changes from SCell to PCell, the identifier of a cell that changes from PSCell to SCG SCell, and the identifier of a cell that changes from SCG SCell to PSCell.

[0352] ■ Measurement information of the above-mentioned cells, such as signal quality and signal strength.

[0353] ■ Information about the service areas to be released, such as the area identifiers of the areas to be released;

[0354] ■ Context related to the user bearer, such as the messages carried by the user bearer;

[0355] ■ The reason for modifying the user context can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, etc.

[0356] Step 2: The centralized unit sends a UE Context ModifiedConfirm message to the distributed unit. This message may contain one or more of the following information:

[0357] ■ Information about the community to be modified, which includes one or more of the following:

[0358] ■ Accepted community signage to be modified;

[0359] ■ The community signage of the community that has not been accepted and is awaiting modification.

[0360] ■Information about the cells to be released, which includes one or more of the following:

[0361] ■Identification of the communities to be released;

[0362] ■Identification of communities awaiting release but not yet accepted.

[0363] ■ Context related to the user bearer, such as information about the user bearer;

[0364] ■ The reason why the centralized unit responds as described above. This information can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, poor uplink or downlink signal quality or strength of the user in the cell, etc.

[0365] If the central unit can accept the cell configuration information in the request message of step 1, the central unit may omit the cell-related information (i.e., information about the cell to be modified, information about the cell to be released) and / or other information (i.e., context related to the user bearer, information about the reason for the central unit's response) in the UE Context Modification Confirm message replied in step 2.

[0366] c. The cell configuration modification process triggered by the distribution unit includes three or four steps, such as... Figure 17 As shown:

[0367] Step 1: The distributed unit sends a UE Context ModifiedRequired message to the centralized unit. This message will contain one or more of the following information:

[0368] ■ The information of the serving cell to be modified includes one or more of the following:

[0369] ■ The identifier for the PCell cell to be modified;

[0370] ■ The identifier for the SCell cell to be modified;

[0371] ■ The identifier of the PSCell cell to be modified;

[0372] ■ The identifier for the SCG SCell cell needs to be modified;

[0373] ■Identifiers of cells whose cell types have changed, indicating the cell type before and after the modification: such as the identifier of a cell that changes from PCcell to SCell, the identifier of a cell that changes from SCell to PCell, the identifier of a cell that changes from PSCell to SCG SCell, and the identifier of a cell that changes from SCG SCell to PSCell.

[0374] ■ Measurement information of the above-mentioned cells, such as signal quality and signal strength.

[0375] ■ Information about the service areas to be released, such as the area identifiers of the areas to be released;

[0376] ■ Context related to the user's bearer, information about the user's bearer;

[0377] ■ The reason for modifying the user context can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, etc.

[0378] Step 2: The centralized unit sends a UE Context ModifiedRequest message to the distributed unit. This message will contain one or more of the following information:

[0379] ■ Cell list information, which contains one or more cells, and includes one or more of the following information:

[0380] ■Community signage;

[0381] ■ Measurement results of the cell, such as signal quality and signal strength.

[0382] ■ Information on newly added serving cells sent by the CU. The newly added cell can be a newly added cell already determined by the centralized unit, or it can be a candidate newly added cell, and includes one or more of the following information:

[0383] ■ Community list information, containing the identifiers of one or more communities;

[0384] ■ Identification information for one or more PCell cells;

[0385] ■ Identification information for one or more SCell cells;

[0386] ■ Identification information for one or more PSCell cells;

[0387] ■ Identification information for one or more SCG SCell cells;

[0388] ■ Measurement information of the above-mentioned cells, such as signal quality and signal strength.

[0389] ■ The information of the serving cell to be modified includes one or more of the following:

[0390] ■ The identifier for the PCell cell to be modified;

[0391] ■ The identifier for the SCell cell to be modified;

[0392] ■ The identifier of the PSCell cell to be modified;

[0393] ■ The identifier for the SCG SCell cell needs to be modified;

[0394] ■Identifiers of cells whose cell types have changed, indicating the cell type before and after the modification: such as the identifier of a cell that changes from PCcell to SCell, the identifier of a cell that changes from SCell to PCell, the identifier of a cell that changes from PSCell to SCG SCell, and the identifier of a cell that changes from SCG SCell to PSCell.

[0395] ■ Measurement information of the above-mentioned cells, such as signal quality and signal strength.

[0396] ■ Information about the service areas to be released, such as the area identifiers of the areas to be released;

[0397] ■ Context related to user bearer and / or identification, such as the user bearer message, user identification information (such as the ID used by the user on the interface between the central unit and the distributed unit, for example, CU UE F1AP ID, which may be newly assigned by the CU, or already assigned to the user by the CU, or both).

[0398] ■ The reason for modifying the user context can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, poor signal quality or strength of the load-balanced user in the cell, poor uplink or downlink signal quality or strength of the user in the cell, etc.

[0399] The cell indicated by the cell-related information in step 2 above may or may not include the cell indicated by the cell-related information included in step 1.

[0400] Step 3: The distributed unit sends a UE Context ModifiedResponse message to the centralized unit. This message may contain one or more of the following information:

[0401] ■ Information about newly added cells sent by the DU, which includes one or more of the following:

[0402] ■ The cell identifier of the newly added cell accepted, or the cell identifier of the newly added cell selected by the distribution unit. Optionally, it indicates the type of the newly added cell, such as PCell, SCell, PSCell, SCG SCell;

[0403] ■The signage for newly added residential communities that were not accepted.

[0404] ■ Information about the community to be modified, which includes one or more of the following:

[0405] ■ Accepted community signage to be modified;

[0406] ■ The community signage of the community that has not been accepted and is awaiting modification.

[0407] ■Information about the cells to be released, which includes one or more of the following:

[0408] ■Identification of the communities to be released;

[0409] ■Identification of communities awaiting release but not yet accepted.

[0410] ■ Context related to the user bearer, such as information about the user bearer;

[0411] ■ The reason for the above response can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, poor signal quality or strength of the load-balanced user in the cell, poor uplink or downlink signal quality or strength of the user in the cell, etc.

[0412] The newly accepted cell in step 3 can be obtained from the cell list information included in step 2 or the newly added serving cell, or it can be another cell. The distribution unit modifies the user's context according to the information in step 3. In addition, if the distribution unit can accept the cell configuration content in the request message in step 2, the distribution unit may omit the aforementioned cell-related information (i.e., the information of the newly added cell sent by the DU, the information of the cell to be modified, and the information of the cell to be released) and / or other information (i.e., the context related to the user bearer, and the reason information for the distribution unit to make the above response) in the UE Context Modification Response message replied in step 3.

[0413] Step 4: The centralized unit sends a UE Context ModifiedConfirm message to the distributed unit. This step is optional, and the message may contain one or more of the following information:

[0414] ■ Information about newly added communities, which includes one or more of the following:

[0415] ■ The community logo for newly added communities accepted;

[0416] ■ Community signage for newly added communities that were not accepted

[0417] ■ Information about the community to be modified, which includes one or more of the following:

[0418] ■ Accepted community signage to be modified;

[0419] ■ The community signage of the community that has not been accepted and is awaiting modification.

[0420] ■Information about the cells to be released, which includes one or more of the following:

[0421] ■Identification of the communities to be released;

[0422] ■Identification of communities awaiting release but not yet accepted.

[0423] ■ Context related to the user bearer, such as information about the user bearer;

[0424] ■ The reason why the centralized unit responds as described above. This information can be specific to each cell or to all modifications. Possible reasons include one or more of the following: cell overload, cell uplink or downlink overload, cell uplink control channel overload, load balancing, poor signal quality or strength of the user in the cell, poor uplink or downlink signal quality or strength of the user in the cell, etc.

[0425] The newly added cell and / or the cell to be modified and / or the cell to be released in step 4 above can be obtained from the newly added cell and / or the serving cell to be modified and / or the serving cell to be released included in step 3, or it can be other cells. The distribution unit modifies the user's context according to the information in step 4. In addition, if the central unit can accept the content about cell configuration in the response message of step 3, the central unit may not include the above-mentioned cell-related information (i.e., information about newly added cells, information about cells to be modified, information about cells to be released) and / or other information (i.e., context related to the user bearer, and information about the reason why the central unit made the above response) in the user context modification confirmation message replied in step 4.

[0426] A third embodiment of the present invention also provides an apparatus for handing over serving cells, such as... Figure 18 As shown, it includes a first transmitting module S10 and a first receiving module S11.

[0427] The first sending module S10 is used for the secondary node to send a secondary node modification request message to the primary node, so that the primary node can switch the serving cell and release the bearer to be released according to the secondary node modification request message.

[0428] The first receiving module S11 is used for the auxiliary node to receive the auxiliary node modification confirmation message returned by the master node in response to the auxiliary node modification requirement message.

[0429] The handover device provided in this invention involves a secondary node sending a secondary node modification request message to a primary node. This allows the primary node to switch serving cells and release bearers to be released based on the secondary node modification request message. This provides a prerequisite for releasing user bearers on the secondary node during subsequent handover based on the secondary node modification request message. The secondary node receives a secondary node modification confirmation message returned by the primary node in response to the secondary node modification request message. This enables the handover of serving cells and the release of bearers to be released on the secondary node based on the secondary node modification request message when there are bearers to be released during handover, greatly improving signaling transmission efficiency and saving signaling resources.

[0430] The fourth embodiment of the present invention also provides an apparatus for handing over serving cells, such as... Figure 19 As shown, it includes a second receiving module S13 and a second transmitting module S12.

[0431] The second receiving module S13 is used for the master node to receive the auxiliary node modification request message sent by the auxiliary node, switch the serving cell and release the bearer to be released according to the auxiliary node modification request message;

[0432] The second sending module S12 is used for the master node to return a modification confirmation message to the slave node in response to the modification request message of the slave node.

[0433] This implementation enables the primary node to switch serving cells and release bearers on the secondary node when switching serving cells and there are bearers to be released, based on the modification request message received from the secondary node. This greatly improves signaling transmission efficiency and saves signaling resources.

[0434] Those skilled in the art will understand that this invention includes devices for performing one or more of the operations described in this application. These devices may be specifically designed and manufactured for the desired purpose, or may include known devices found in general-purpose computers. These devices have computer programs stored therein that can be selectively activated or reconfigured. Such computer programs may be stored in a device (e.g., a computer)-readable medium or in any type of medium suitable for storing electronic instructions and coupled to a bus, including but not limited to any type of disk (including floppy disks, hard disks, optical disks, CD-ROMs, and magneto-optical disks), ROM (Read-Only Memory), RAM (Random Access Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory, magnetic cards, or optical cards. That is, a readable medium includes any medium by which a device (e.g., a computer) stores or transmits information in a readable form.

[0435] Those skilled in the art will understand that each block in these structural diagrams and / or block diagrams and / or flow diagrams, as well as combinations of blocks in these structural diagrams and / or block diagrams and / or flow diagrams, can be implemented using computer program instructions. Those skilled in the art will also understand that these computer program instructions can be provided to a processor of a general-purpose computer, a specialized computer, or other programmable data processing method for implementation, thereby enabling the processor of the computer or other programmable data processing method to execute the schemes specified in the blocks or plurality of blocks of the structural diagrams and / or block diagrams and / or flow diagrams disclosed herein.

[0436] Those skilled in the art will understand that the steps, measures, and schemes in the various operations, methods, and processes discussed in this invention can be alternated, modified, combined, or deleted. Furthermore, other steps, measures, and schemes in the various operations, methods, and processes discussed in this invention can also be alternated, modified, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and schemes in the prior art that are similar to those disclosed in this invention can also be alternated, modified, rearranged, decomposed, combined, or deleted.

[0437] The above description is only a partial embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method executed by a first network entity, a centralized unit (CU) corresponding to a network node in a wireless communication system, characterized in that, include: A request message for requesting context establishment of a user equipment (UE) is sent to a second network entity corresponding to a distribution unit (DU). The request message includes: first identification information of a special cell and a first list of at least one candidate special cell. Since the first identification information of the special cell is not accepted by the second network entity, a first response message is received from the second network entity. The first response message includes the second identification information of the special cell related to the selection of a suitable special cell.

2. The method according to claim 1, characterized in that, The special cell associated with the appropriate special cell selection is one of the at least one candidate special cells; The first response message also includes the reason associated with the special cell that the second network entity did not accept.

3. The method according to claim 2, characterized in that, The cause indicates that the specific cell is overloaded.

4. The method according to claim 1, characterized in that, The request message and the first response message are transmitted via the F1 interface between a first network entity corresponding to the CU and a second network entity corresponding to the DU.

5. The method according to claim 1, characterized in that, The method further includes: Send a modification request message for the secondary node SN to the network entity corresponding to the primary node MN; Receive a message from the network entity corresponding to the MN to confirm the SN modification request message; The SN modification request message includes at least one of the following: secondary cell group (SCG) configuration information, a list of at least one bearer to be modified, and information of the tunnel endpoint at the SCG, wherein the tunnel endpoint information is used to transmit data of at least one bearer.

6. The method according to claim 1, characterized in that, The method further includes: Send a message to the second network entity corresponding to the DU to request context modification of the UE; Receive a message from the second network entity corresponding to the DU to confirm the context modification of the UE.

7. The method according to claim 6, characterized in that, The message used to request context modification of the UE includes a second list of at least one SCell to be established; The message used to confirm the context modification of the UE includes: a third list of at least one failed SCell establishment, and the reason associated with the at least one failed SCell establishment.

8. The method according to claim 7, characterized in that, The cause indicated that the DU failed to establish an SCell overload.

9. A first network entity corresponding to a centralized unit (CU) of a network node, characterized in that, include: A transceiver configured to transmit and receive signals; And at least one processor, said at least one processor being configured to perform the method of any one of claims 1-8.

10. A method performed by a second network entity in a wireless communication system, corresponding to a distribution unit (DU) of a network node, characterized in that, include: A request message for requesting context establishment of a user equipment (UE) is received from a first network entity corresponding to a central unit (CU). The request message includes: first identification information of a special cell and a first list of at least one candidate special cell. Since the first identification information of the special cell is not accepted by the second network entity, a first response message is sent to the first network entity corresponding to the CU. The first response message includes the second identification information of the special cell related to the selection of a suitable special cell.

11. The method according to claim 10, characterized in that, The special cell associated with the selection of a suitable special cell is one of the at least one candidate special cells; The first response message also includes the reason associated with the special cell that the second network entity did not accept.

12. The method according to claim 11, characterized in that, The cause indicates that the specific cell is overloaded.

13. The method according to claim 10, characterized in that, The request message and the first response message are transmitted via the F1 interface between a first network entity corresponding to the CU and a second network entity corresponding to the DU.

14. The method according to claim 10, characterized in that, The auxiliary node SN modifies the request message and sends it to the network entity corresponding to the master node MN through the first network entity corresponding to the CU. The message used to confirm the SN modification requires a message is sent through the network entity corresponding to the MN to the first network entity corresponding to the CU.

15. The method according to claim 10, characterized in that, The method further includes: Receive a message from the first network entity corresponding to the CU requesting context modification for the UE; A message is sent to the first network entity corresponding to the CU to confirm the context modification of the UE.

16. The method according to claim 15, characterized in that, The message used to request context modification of the UE includes a second list of at least one SCell to be established; The message used to confirm the context modification of the UE includes: a third list of at least one failed SCell establishment, and the reason associated with the at least one failed SCell establishment.

17. The method according to claim 16, characterized in that, The cause indicated that the DU failed to establish an SCell overload.

18. A second network entity corresponding to a distribution unit DU of a network node, characterized in that, include: A transceiver configured to transmit and receive signals; And at least one processor, said at least one processor being configured to perform the method of any one of claims 10-17.

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