Method, apparatus and computer program

Abstract

There is provided an apparatus comprising means for communicating with a user equipment, where the user equipment is served by a serving cell provided by a source node, and means for receiving an indication that the user equipment is moving from the serving cell to a target cell, the apparatus further comprising means for communicating with the user equipment based on the received indication, means for i) retaining configuration information associated with the configuration for the user equipment, and ii) resetting information on at least one protocol layer associated with the configuration for the user equipment.

Description

Technical Field

[0001] The present application relates to methods, apparatuses, and computer programs for wireless communication systems. Background Art

[0002] A communication system can be a facility that enables a communication session between two or more entities (such as user terminals, base stations / access points, and / or other nodes) by providing a carrier between the various entities involved in the communication path. A communication system can be provided, for example, by means of a communication network and one or more compatible communication devices. A communication session can include, for example, data communication for carrying communications (such as voice, email, text messages, multimedia, and / or content data, etc.). Non-limiting examples of the services provided include two-way or multi-way calls, data communication or multimedia services, and access to a data network system (such as the Internet). Summary of the Invention

[0003] According to one aspect, there is provided an apparatus including: means for communicating with a user equipment, wherein the user equipment is served by a serving cell provided by a source node; means for receiving an indication that the user equipment is moving from the serving cell to a target cell; and means for performing the following operations based on the received indication: i) retaining configuration information associated with the configuration for the user equipment, and ii) resetting information regarding at least one protocol layer associated with the configuration for the user equipment.

[0004] In one example, the configuration for the user equipment is a user equipment context.

[0005] In one example, the apparatus includes: means for reconnecting with the user equipment using the configuration information associated with the user equipment, such that the user equipment is served by a cell of the source node.

[0006] In one example, the configuration information associated with the configuration for the user equipment to be retained is received in a user equipment context setup request message.

[0007] In one example, the configuration information includes user plane transport network layer information associated with the user equipment.

[0008] In one example, the means for resetting information regarding at least one protocol layer includes: means for resetting resources associated with the configuration for the user equipment.

[0009] In one example, the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

[0010] In one example, the component for resetting information about at least one protocol layer includes at least one of the following: a component for resetting signaling transmission resources associated with the configuration for the user equipment; a component for resetting user data transmission resources associated with the configuration for the user equipment; a component for performing radio link control re-establishment associated with the configuration for the user equipment; a component for performing media access control reset associated with the configuration for the user equipment; a component for creating at least one tunnel endpoint identifier for at least one data radio bearer associated with the configuration for the user equipment; a component for maintaining at least one existing tunnel endpoint identifier associated with the configuration for the user equipment.

[0011] In one example, the component for maintaining at least one existing tunnel endpoint identifier includes: a component for refreshing the existing tunnel associated with the tunnel endpoint identifier.

[0012] In one example, the component for refreshing includes: a component for discarding the data included in the existing tunnel.

[0013] In one example, the component for creating at least one tunnel endpoint identifier includes: a component for determining the resources for the tunnel associated with at least one tunnel endpoint identifier.

[0014] In one example, the component for creating a tunnel endpoint identifier for at least one data radio bearer associated with the user equipment includes: a component for receiving, from the central unit, the uplink user plane transport network layer information with an indication; and a component for applying the uplink user plane transport network layer information after the user equipment has moved from the serving cell to the target cell.

[0015] In one example, the uplink user plane transport network layer information is included in the list of data radio bearers to be modified.

[0016] In one example, the indication is received in one of the following: F1 application protocol message, and Xn application protocol message.

[0017] In one example, the F1 application protocol message is one of the following: user equipment context modification request message, user equipment context release command message, and user equipment context reset request message.

[0018] In one example, the indication is received from a second node.

[0019] In one example, the second node is one of the following: central unit, master node, target node, gNodeB central unit.

[0020] In one example, one of the following: the apparatus is for a source node, the apparatus is included in the source node, and the apparatus is the source node.

[0021] In one example, the source node is one of the following: a gNodeB, a source distributed unit, and a source gNodeB.

[0022] According to one aspect, there is provided an apparatus, comprising: means for communicating with a user equipment via a source node, wherein the user equipment is served by a serving cell provided by the source node; and means for providing an indication to the source node that the user equipment is moving from the serving cell to a target cell, wherein the indication is for the source node: i) to retain configuration information associated with the configuration for the user equipment, and ii) to reset information regarding at least one protocol layer associated with the configuration for the user equipment.

[0023] In one example, the configuration for the user equipment is a user equipment context.

[0024] In one example, the apparatus comprises: means for receiving, from the source node, signaling for reconnecting with the user equipment using the configuration information associated with the user equipment, such that the user equipment is served by a cell of the source node.

[0025] In one example, the apparatus comprises: means for providing, to the source node, in a user equipment context setup request message, the configuration for the user equipment to be retained.

[0026] In one example, the configuration information includes user plane transport network layer information associated with the user equipment.

[0027] In one example, the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

[0028] In one example, the apparatus comprises: means for providing, to the source node, uplink user plane transport network layer information with the indication, wherein the source node is instructed to apply the uplink user plane transport network layer information after the user equipment has moved from the serving cell to the target cell.

[0029] In one example, the uplink user plane transport network layer information is included in a list of data radio bearers to be modified.

[0030] In one example, the indication is provided in one of the following: an F1 application protocol message, and an Xn application protocol message.

[0031] In one example, the F1 application protocol message is one of the following: a user equipment context modification request message, a user equipment context release command message, and a user equipment context reset request message.

[0032] In one example, one of the following: the apparatus is for a second node, the apparatus is included in the second node, and the apparatus is the second node.

[0033] In one example, the second node is one of the following: a central unit, a master node, a gNodeB central unit.

[0034] According to one aspect, a method is provided, which includes: communicating with a user equipment, where the user equipment is served by a serving cell provided by a source node; receiving an indication that the user equipment is moving from the serving cell to a target cell; and based on the received indication, performing the following operations: i) retaining configuration information associated with the configuration for the user equipment, and ii) resetting information regarding at least one protocol layer associated with the configuration for the user equipment.

[0035] In one example, the method includes: reconnecting with the user equipment using the configuration information associated with the user equipment such that the user equipment is served by a cell of the source node.

[0036] In one example, the configuration information associated with the configuration for the user equipment to be retained is received in a user equipment context setup request message.

[0037] In one example, the configuration information includes user plane transport network layer information associated with the user equipment.

[0038] In one example, resetting information regarding at least one protocol layer includes: resetting resources associated with the configuration for the user equipment.

[0039] In one example, the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

[0040] In one example, resetting information regarding at least one protocol layer includes at least one of the following: resetting signaling transport resources associated with the configuration for the user equipment; resetting user data transport resources associated with the configuration for the user equipment; performing radio link control re-establishment associated with the configuration for the user equipment; performing media access control reset associated with the configuration for the user equipment; creating at least one tunnel endpoint identifier for at least one data radio bearer associated with the configuration for the user equipment; maintaining at least one existing tunnel endpoint identifier associated with the configuration for the user equipment.

[0041] In one example, maintaining at least one existing tunnel endpoint identifier includes: refreshing an existing tunnel associated with the tunnel endpoint identifier.

[0042] In one example, refreshing includes: discarding data included in the existing tunnel.

[0043] In one example, creating at least one tunnel endpoint identifier includes: determining resources for a tunnel associated with the at least one tunnel endpoint identifier.

[0044] In one example, creating a tunnel endpoint identifier for at least one data radio bearer associated with a user equipment includes: receiving, from a central unit, uplink user plane transport network layer information with an indication; and applying the uplink user plane transport network layer information after the user equipment has moved from a serving cell to a target cell.

[0045] In one example, the uplink user plane transport network layer information is included in a list of data radio bearers to be modified.

[0046] In one example, the indication is received in one of the following: an F1 application protocol message, and an Xn application protocol message.

[0047] In one example, the F1 application protocol message is one of the following: a user equipment context modification request message, a user equipment context release command message, and a user equipment context reset request message.

[0048] In one example, the indication is received from a second node.

[0049] In one example, the second node is one of the following: a central unit, a master node, a target node, a gNodeB central unit.

[0050] In one example, the method is performed by a source node.

[0051] In one example, the source node is one of the following: a gNodeB, a source distributed unit, and a source gNodeB.

[0052] According to one aspect, a method is provided that includes: communicating with a user equipment via a source node, where the user equipment is served by a serving cell provided by the source node; and providing an indication to the source node that the user equipment is moving from the serving cell to a target cell, where the indication is for the source node to: i) retain configuration information associated with a configuration for the user equipment, and ii) reset information regarding at least one protocol layer associated with the configuration for the user equipment.

[0053] In one example, the configuration for the user equipment is a user equipment context.

[0054] In one example, the method includes: receiving, from a source node, signaling to reconnect with a user equipment using configuration information associated with the user equipment such that the user equipment is served by a cell of the source node.

[0055] In one example, the method includes: providing, in a user equipment context setup request message, to the source node, configuration to be reserved for the user equipment.

[0056] In one example, the configuration information includes user plane transport network layer information associated with the user equipment.

[0057] In one example, the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

[0058] In one example, the method includes: providing, to the source node, uplink user plane transport network layer information with an indication, wherein the source node is instructed to apply the uplink user plane transport network layer information after the user equipment has moved from a serving cell to a target cell.

[0059] In one example, the uplink user plane transport network layer information is included in a list of data radio bearers to be modified.

[0060] In one example, the indication is provided in one of: an F1 application protocol message, and an Xn application protocol message.

[0061] In one example, the F1 application protocol message is one of: a user equipment context modification request message, a user equipment context release command message, and a user equipment context reset request message.

[0062] In one example, the method is performed by a second node.

[0063] In one example, the second node is one of: a central unit, a master node, a gNodeB central unit.

[0064] According to one aspect, there is provided an apparatus, comprising: at least one processor, and at least one memory storing instructions that, when executed by one or more processors, cause the apparatus to perform: communicating with a user equipment, wherein the user equipment is served by a serving cell provided by a source node; receiving an indication that the user equipment is moving from the serving cell to a target cell; and based on the received indication, performing: i) retaining configuration information associated with the configuration for the user equipment, and ii) resetting information regarding at least one protocol layer associated with the configuration for the user equipment.

[0065] In one example, the apparatus performs: reconnecting with the user equipment using configuration information associated with the user equipment such that the user equipment is served by a cell of the source node.

[0066] In one example, the configuration information associated with the configuration for the user equipment to be retained is received in a user equipment context setup request message.

[0067] In one example, the configuration information includes user plane transport network layer information associated with the user equipment.

[0068] In one example, resetting information about at least one protocol layer includes: resetting resources associated with the configuration for the user equipment.

[0069] In one example, the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

[0070] In one example, resetting information about at least one protocol layer includes at least one of the following: resetting signaling transport resources associated with the configuration for the user equipment; resetting user data transport resources associated with the configuration for the user equipment; performing radio link control re-establishment associated with the configuration for the user equipment; performing media access control reset associated with the configuration for the user equipment; creating at least one tunnel endpoint identifier for at least one data radio bearer associated with the configuration for the user equipment; maintaining at least one existing tunnel endpoint identifier associated with the configuration for the user equipment.

[0071] In one example, maintaining at least one existing tunnel endpoint identifier includes: refreshing an existing tunnel associated with the tunnel endpoint identifier.

[0072] In one example, refreshing includes: discarding data included in the existing tunnel.

[0073] In one example, creating at least one tunnel endpoint identifier includes: determining resources for a tunnel associated with at least one tunnel endpoint identifier.

[0074] In one example, creating tunnel endpoint identifiers for at least one data radio bearer associated with the user equipment includes: receiving uplink user plane transport network layer information with an indication from a central unit; and applying the uplink user plane transport network layer information after the user equipment has moved from a serving cell to a target cell.

[0075] In one example, the uplink user plane transport network layer information is included in a list of data radio bearers to be modified.

[0076] In one example, the indication is received in one of the following: an F1 application protocol message, and an Xn application protocol message.

[0077] In one example, the F1 application protocol message is one of the following: a user equipment context modification request message, a user equipment context release command message, and a user equipment context reset request message.

[0078] In one example, the indication is received from a second node.

[0079] In one example, the second node is one of the following: a central unit, a master node, a target node, a gNodeB central unit.

[0080] In one example, one of the following: the apparatus is for a source node, the apparatus is included in the source node, and the apparatus is the source node.

[0081] In one example, the source node is one of the following: a gNodeB, a source distributed unit, and a source gNodeB.

[0082] According to one aspect, there is provided an apparatus comprising: at least one processor, and at least one memory storing instructions that, when executed by one or more processors, cause the apparatus to perform: communicate with a user equipment via a source node, wherein the user equipment is served by a serving cell provided by the source node; and provide an indication to the source node that the user equipment is moving from the serving cell to a target cell, wherein the indication is for the source node to: i) retain configuration information associated with the configuration for the user equipment, and ii) reset information regarding at least one protocol layer associated with the configuration for the user equipment.

[0083] In one example, the method includes: receiving, from a source node, signaling to reconnect with the user equipment using configuration information associated with the user equipment such that the user equipment is served by a cell of the source node.

[0084] In one example, the method includes: providing, in a user equipment context setup request message, the configuration for the user equipment to be retained to the source node.

[0085] In one example, the configuration information includes user plane transport network layer information associated with the user equipment.

[0086] In one example, the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

[0087] In one example, the method includes: providing to a source node uplink user plane transport network layer information with an indication, wherein the source node is instructed to apply the uplink user plane transport network layer information after the user equipment has moved from a serving cell to a target cell.

[0088] In one example, the uplink user plane transport network layer information is included in a list of data radio bearers to be modified.

[0089] In one example, the indication is provided in one of the following: an F1 application protocol message, and an Xn application protocol message.

[0090] In one example, the F1 application protocol message is one of the following: a user equipment context modification request message, a user equipment context release command message, and a user equipment context reset request message.

[0091] In one example, the method is performed by a second node.

[0092] In one example, the second node is one of the following: a central unit, a master node, a gNodeB central unit.

[0093] According to one aspect, there is provided a computer program comprising instructions that, when executed by a device, cause the device to at least perform the following operations: communicate with a user equipment, wherein the user equipment is served by a serving cell provided by a source node; receive an indication that the user equipment is moving from the serving cell to a target cell; and based on the received indication, perform the following operations: i) retain configuration information associated with a configuration for the user equipment, and ii) reset information about at least one protocol layer associated with the configuration for the user equipment.

[0094] According to one aspect, there is provided a computer program comprising instructions that, when executed by a device, cause the device to at least perform the following operations: communicate with a user equipment via a source node, wherein the user equipment is served by a serving cell provided by the source node; and provide to the source node an indication that the user equipment is moving from the serving cell to a target cell, wherein the indication is for the source node: i) retain configuration information associated with a configuration for the user equipment, and ii) reset information about at least one protocol layer associated with the configuration for the user equipment.

[0095] According to one aspect, there is provided a computer program comprising instructions stored thereon to perform the method as described herein.

[0096] A computer program product stored on a medium can cause a device to perform the method as described herein.

[0097] A non-transitory computer-readable medium includes program instructions that, when executed by a device, cause the device to perform the methods described herein.

[0098] An electronic device may include the device described herein.

[0099] In the foregoing, various aspects have been described. It should be understood that further aspects may be provided by any combination of two or more of the various aspects described above.

[0100] Various other aspects and further embodiments are also described in the following detailed description and the appended claims.

[0101] According to some aspects, the subject matter of the independent claims is provided. Some further aspects are defined in the dependent claims. Embodiments not within the scope of the claims are to be construed as examples that help to understand the present disclosure.

[0102] List of Abbreviations:

[0103] AF: Application Function

[0104] AMF: Access Management Function

[0105] AN: Access Network

[0106] BS: Base Station

[0107] CN: Core Network

[0108] CPA: Conditional PSCell Addition

[0109] CPC: Conditional PSCell Change

[0110] DL: Downlink

[0111] eNB: eNodeB

[0112] gNB: gNodeB IIoT: Industrial Internet of Things

[0113] LTE: Long-Term Evolution

[0114] NEF: Network Exposure Function

[0115] NG-RAN: Next Generation Radio Access Network

[0116] NF: Network Function

[0117] NR: New Radio

[0118] NRF: Network Repository Function

[0119] NW: Network

[0120] MS: Mobile Station

[0121] PCF: Policy Control Function

[0122] PDCP: Packet Data Convergence Protocol

[0123] PLMN: Public Land Mobile Network

[0124] PSCell: Primary Serving Cell

[0125] RAN: Radio Access Network

[0126] RF: Radio Frequency

[0127] SMF: Session Management Function

[0128] UE: User Equipment

[0129] UDR: Unified Data Repository

[0130] UDM: Unified Data Management

[0131] UL: Uplink

[0132] UPF: User Plane Function

[0133] 3GPP: 3rd Generation Partnership Project

[0134] 5G: Fifth Generation

[0135] 5GC: 5G Core Network

[0136] 5G-AN: 5G Radio Access Network 5GS: 5G System Description of the Drawings

[0137] Embodiments will now be described with reference to the drawings by way of example only, where:

[0138] Figure 1 A schematic diagram showing a 5G system is shown;

[0139] Figure 2 A schematic diagram showing a control device is shown;

[0140] Figure 3 A schematic diagram showing a terminal is shown;

[0141] Figure 4 A schematic diagram showing a user equipment moving from a source cell to a target cell is shown;

[0142] Figure 5 A signaling diagram between a user equipment and a network entity for conditional PSCell change is shown;

[0143] Figure 6Shows a signaling diagram between a user equipment and a network entity for serving cell change according to a first example;

[0144] Figure 7 Shows a signaling diagram between a user equipment and a network entity for serving cell change according to a second example;

[0145] Figure 8 Shows a signaling diagram between a user equipment and a network entity for serving cell change according to a third example;

[0146] Figure 9 Shows a flowchart of a method performed by one device;

[0147] Figure 10 Shows a flowchart of a method performed by another device; and

[0148] Figure 11 Shows a schematic diagram of a non - volatile memory medium storing instructions that, when executed by a processor, allow the processor to perform Figure 9 and Figure 10 one or more steps of the method. Detailed Description

[0149] Before detailing some examples of the present disclosure, refer to Figures 1 to 3 briefly describe some general principles of wireless communication systems and mobile communication devices to assist in understanding the basic technology of the described examples.

[0150] In a wireless communication system 100 such as Figure 1 shown, a mobile communication device / terminal or user device, and / or user equipment (UE), and / or machine - type communication device 102 is provided with wireless access via at least one base station (not shown) or similar wireless transmitting and / or receiving node or point. The communication device is provided with appropriate signal receiving and transmitting means to enable communication, for example, such that it can access a communication network or communicate directly with other devices. The communication device can access a carrier provided by a base station or access point and transmit and / or receive communications on that carrier.

[0151] Hereinafter, some examples are described with reference to a mobile communication device capable of communicating via a wireless cellular system and a mobile communication system serving such a mobile communication device. Before detailing the examples of the present disclosure, refer to Figure 1 、 Figure 2 and Figure 3 briefly describe some general principles of wireless communication systems, their access systems, and mobile communication devices to assist in understanding the basic technology of the described examples.

[0152] Figure 1Shows a schematic representation of a wireless communication system 100. The wireless communication system 100 may include one or more devices 102, such as user equipment (UE) or terminals. The wireless communication system 100 may also include a 5G system (5GS), as shown. The 5GS includes a 5G radio access network (5G-RAN) 106, a 5G core network (5G-CN) 104 including one or more network functions (NFs), one or more application functions (AFs) 108, and one or more data networks (DNs) 110.

[0153] The 5G-RAN 106 may include one or more gNodeB (gNB) distributed unit (DU) functions, which are connected to one or more gNodeB (gNB) central unit (CU) functions.

[0154] The 5G-CN 104 may include an access management function (AMF) 112, a session management function (SMF) 114, an authentication server function (AUSF) 116, a user data management function (UDM) 118, a user plane function (UPF) 120, a network exposure function (NEF) 122, and / or other NFs. Some examples as shown below may apply to the 3GPP 5G standard. However, some examples may also apply to 5G-advanced, 4G, 3G, and other 3GPP standards.

[0155] In a wireless communication system 100 such as Figure 1 shown, a mobile communication device / terminal or user equipment, and / or user equipment (UE), and / or a machine type communication device 102 is provided with wireless access via at least one base station (not shown) or a similar wireless transmitting and / or receiving node or point. The terminal is provided with appropriate signal receiving and transmitting means to enable communication, for example, to be able to access a communication network or directly communicate with other devices. The communication device may access a carrier provided by a base station or an access point and transmit and / or receive communications on that carrier.

[0156] Figure 2 Shows for controlling as Figure 1An example of a control device 200 for functions of 5G-RAN or 5GC as shown. The control device may include at least one random access memory (RAM) 211a, at least one read-only memory (ROM) 211b, at least one processor 212, 213, and an input / output interface 214. The at least one processor 212, 213 may be coupled to the RAM 211a and the ROM 211b. The at least one processor 212, 213 may be configured to execute appropriate software code 215. The software code 215, for example, may allow execution of one or more steps to perform one or more aspects of the proposed aspects. The software code 215 may be stored in the ROM 211b. The control device 200 may be interconnected with another control device 200 that controls another function of 5G-AN or 5GC. In some examples, each function of 5G-AN or 5GC includes a control device 200. In alternative examples, two or more functions of 5G-AN or 5GC may share a control device.

[0157] Figure 3 An example of a terminal 300 such as Figure 1 as shown in is shown. The terminal 300 may be provided by any device capable of sending and receiving radio signals. Non-limiting examples include user equipment, a mobile station (MS) or a mobile device (such as a mobile phone or a so-called "smartphone"), a computer equipped with a wireless interface card or other wireless interface device (e.g., a USB dongle), a personal digital assistant (PDA) or a tablet computer having wireless communication capabilities, a machine type communication (MTC) device, a cellular Internet of Things (CIoT) device, or any combination of these devices, etc. The terminal 300 may provide, for example, transmission of data for carrying communications. The communications may be one or more of voice, email, text messages, multimedia, data, machine data, etc.

[0158] The terminal 300 may receive signals via an air interface or a radio interface 307 through appropriate means for reception, and may send signals via appropriate means for sending radio signals. In Figure 3 it, the transceiver device is schematically represented by block 306. The transceiver device 306 may be provided, for example, by means of radio components and associated antenna devices. The antenna device may be arranged inside or outside the mobile device.

[0159] The terminal 300 may be provided with at least one processor 301, at least one memory ROM 302a, at least one RAM 302b, and other possible components 303 for use in the software and hardware assisted execution of the tasks it is designed to perform, including controlling access to and communication with access systems and other communication devices. The at least one processor 301 is coupled to the RAM 302b and the ROM 302a. The at least one processor 301 may be configured to execute appropriate software code 308. The software code 308 may, for example, allow the execution of one or more of the proposed aspects. The software code 308 may be stored in the ROM 302a.

[0160] The processor, storage device, and other associated control means may be provided on a suitable circuit board and / or chipset. This feature is denoted by reference numeral 304. The device may optionally have a user interface such as a keyboard 305, a touch screen or touchpad, a combination thereof, etc. Optionally, depending on the type of device, one or more of a display, a speaker, and a microphone may be provided.

[0161] One or more of the following examples may relate to cell handover and serving cell change. Handover is a process in telecommunications and mobile communications where a cellular connection is transferred from one cell to another without disconnecting the session.

[0162] According to the Rel.17 provisions of the 3GPP 5G standard, the UE releases all stored conditional reconfiguration information after successfully executing the conditional primary serving cell (PSCell) change (CPC) procedure. However, in the mobility enhancement work item of Rel.18 (RP-213565), there are already objectives including: i) specifying mechanisms and procedures for new radio dual connectivity (NR-DC) and selective activation of cell groups via L3 enhancements (at least for the secondary cell group (SCG)), and ii) allowing subsequent cell group changes after changing the cell group (CG) without reconfiguring and restarting the CPC / conditional PSCell addition (CPA).

[0163] Figure 4 A schematic representation of a user equipment moving from a source cell to a target cell is shown. In Figure 4 the two-way arrows indicate two-way communication between two related entities.

[0164] A user equipment (UE) 401 is provided that moves from a first position to a second position. The movement of the UE 401 is shown by the block arrow. The first position is within the coverage of a first cell 403. When the UE 401 is located within the area of the first cell 403, the UE 401 is served by the first cell 403. The first cell 403 is provided by a first gNB 405. The first gNB 405 includes a distributed unit (DU) (not shown) that provides the first cell 403.

[0165] When the UE 401 moves (physically) from the first position to the second position, the UE 401 may change cells. This may be referred to as a handover. In some examples, the handover may be a conditional handover (CHO), or a conditional primary serving cell change (CPC).

[0166] In Figure 4 this, the serving cell of the UE 401 changes from the first cell 403 to a second cell 407. The second cell 407 is provided by a second gNB 409. The second gNB 409 includes a distributed unit (DU) (not shown) that provides the second cell 407. In some other examples, the UE 401 may change to a target cell, whereby the source cell and the target cell are provided by the same gNB (with different DUs). In some other examples, the UE 401 may change to a target cell, whereby the source cell and the target cell are provided by the same gNB and the same DU.

[0167] The first gNB 405 and the second gNB 409 are capable of communicating with a central unit (CU) 411. The CU 411 may be provided by another gNB. The CU 411 is used to change the serving cell of the UE 401 from the first cell 40 to the second cell 407.

[0168] Once the UE 401 has successfully moved to the second cell 407 and connected to the second gNB 409, the UE 401 stops communicating with the first gNB 405. At this time, all uplink and downlink communications will be with the second gNB 409.

[0169] Figure 5 A signaling diagram between a user equipment and network entities for a conditional PSCell change is shown. At the start of the process, the UE is connected to the source gNB-DU, such that uplink and downlink data is transmitted between the UE and the source gNB-DU via the gNB-CU.

[0170] At S501, the UE sends a measurement report to the source gNB-DU.

[0171] At S502, the source gNB-DU sends an uplink resource radio control (RRC) message transmission to the gNB-CU.

[0172] At S503, the gNB-CU sends a UE context setup request to the target gNB-DU.

[0173] At S504, the target gNB-DU sends a UE context setup response message to the gNB-CU.

[0174] At S505, the gNB-CU sends a downlink RRC message transmission to the source gNB-DU.

[0175] At S506, the source gNB-DU sends an RRC reconfiguration message to the UE.

[0176] At S507, the UE sends an RRC reconfiguration complete message to the source gNB-DU.

[0177] At S508, the source gNB-DU sends an uplink RRC message transmission to the gNB-CU.

[0178] At S509, the UE determines that the conditions for PSCell change are met. This can be referred to as the execution conditions being met.

[0179] At S510, the UE and the target gNB-DU perform a random access procedure with each other. Once the random access procedure is successfully completed, the target gNB-DU provides an "access success" indication to the gNB-CU.

[0180] At S511, the UE sends an RRC reconfiguration complete message to the target gNB-DU.

[0181] At S512, the target gNB-DU sends an uplink RRC message transmission to the gNB-CU.

[0182] At S513, the gNB-CU sends a UE context modification request to the target gNB-DU. After modifying the UE context at the target gNB-DU, downlink and uplink data can be transmitted between the UE and the target gNB-DU via the gNB-CU.

[0183] At S514, the target gNB-DU sends a UE context modification response message to the gNB-CU.

[0184] At S515, the gNB-CU sends a UE context release command to the target gNB-DU.

[0185] At S516, the target gNB-DU sends a UE context release complete message to the gNB-CU.

[0186] Once steps S501 to S516 have been completed, the UE has successfully changed the serving cell from the cell of the source gNB-DU to the cell of the target gNB-DU.

[0187] As Figure 5 shown, after the UE performs random access to the target DU (S510), the CU is notified of the "access success" message. Subsequently, the CU instructs to modify the UE context (S513). The UE context modification includes stopping the data radio bearer (DRB) that transmits data towards the UE, and requesting the source DU to send the downlink data transfer status to the CU. Once the source DU confirms the change of the UE context modification, the CU instructs to release the UE context (S515) and release all relevant signaling and data transmission resources reserved for the UE.

[0188] The UE can be configured with selective activation for conditional handover (CHO) or for CPC (where the candidate cells are in candidate gNB-DUs). Selective activation allows subsequent cell group changes after changing the cell group without reconfiguring and restarting CPC / CPA. In other words, the network configures the UE with multiple handover configurations at once to allow the UE to perform handovers from one cell to another cell without any further handover-related configuration.

[0189] When the CHO or CPC handover execution conditions are met to move to the target cell, the UE moves from the source gNB-DU that controls the serving cell to the target gNB-DU.

[0190] In these scenarios, the network instructs the UE to move freely and seamlessly between cells. Since the UE context in the source cell can be released after handover when selective activation is not used, if the UE returns to the source cell again in a "ping-pong" scenario, additional configuration is required. The so-called "ping-pong" scenario is when the UE switches to the target cell in a short period of time and then switches back to the initial source cell. On the other hand, when the UE context is not released when selective activation is not used, this can lead to problems associated with layers such as the RLC layer and the MAC layer. For example, this can cause the RLC and MAC layers to have old protocol data units (PDUs), timeouts, incorrect status variables, incomplete procedures, etc. Therefore, when the UE returns to the source gNB-DU, the UE context is not available.

[0191] One or more of the following examples are intended to solve one or more of the above problems.

[0192] In the example, the UE is connected to a serving cell provided by a source node. The connection between the UE and the source node allows uplink / downlink communication between these entities. Subsequently, the UE can switch to a different serving cell. This is, for example, due to the UE moving its location.

[0193] The source node then receives an indication that the UE is moving from the serving cell to the target cell. The source node will then, based on the received indication: i) retain the configuration information associated with the configuration for the UE, and ii) reset the information regarding at least one protocol layer associated with the configuration for the user equipment.

[0194] In this way, if the UE is going to move / handoff back to the cell provided by the source node, the UE and the source node can connect more quickly using the retained UE configuration instead of performing a "full" configuration process.

[0195] In the following example, the source node can be the source DU. The source DU can be provided in a gNB (i.e., the source gNB-DU). The target node can be the target DU. The target DU can be provided in a gNB (i.e., the target gNB-DU). Hereinafter, the second node can be the CU. The CU can be provided in a gNB (i.e., the gNB-CU).

[0196] In some examples, there is a mechanism by which, after the serving cell changes from the source DU, the UE context is partially released at the source DU. This enables the UE to return to the same DU (i.e., the source DU) without any additional reconfiguration. In the example, a "new" indication is provided from the CU to the source DU to maintain the transport layer resources associated with the UE. The indication also instructs the source DU to release / repare / reset the information related to the communication layer / protocol layer (such as, for example, the MAC layer and the RLC layer). In some examples, this can include resetting the MAC layer and RLC layer buffers. Reparing / resetting the communication layer / protocol layer can include resetting the configuration to zero. Alternatively, reparing or resetting other configurations can include resetting the configuration to its default value.

[0197] In other words, when resetting or reconstructing the MAC layer and the RLC layer, the UE configuration received for the UE is retained at the source DU / source node.

[0198] In some examples, a MAC reset is performed. The MAC reset can be performed according to the specification of 3GPP 38.321, 5.12. In some examples, an RLC reconstruction is performed. The RLC reconstruction can be performed according to the specification of 3GPP 38.322, 5.1.2.

[0199] In some examples, for CHO or CPC, once the preparation phase and the execution phase are completed, the completion phase is executed. During the completion phase, the UE configuration in the source gNB is retained so that the UE can "return" to the previous serving cell when selective activation or continuous CPC / CHO is configured for that cell. The preparation phase includes obtaining the configuration at the target node and providing it to the UE. The execution phase includes the UE completing random access and reconfiguration towards the target cell. The completion phase includes stopping the transmission at the source DU and performing a path switch for the user plane towards the target DU.

[0200] The described mechanism can be applicable to: i) inter-gNB inter-DU CHO or CPC, whereby the UE switches to a different gNB and thus to a different DU; ii) intra-gNB inter-DU CHO or CPC, whereby the UE switches to the same gNB but to a new cell from a different DU; and iii) intra-gNB intra-DU CHO or CPC, whereby the UE switches to the same gNB and the same DU but to a different cell of the same DU.

[0201] In some examples, to enable early data forwarding to the source gNB-DU, the user plane (UP) transport network layer (TNL) information is retained at the source DU even after the UE has moved to the target DU.

[0202] In some examples, the source DU receives the UE context / UE configuration associated with the UE from the CU. This UE context / UE configuration can be received from the CU in a UE context setup request message at the source DU (similar to the target DU receiving a message in S503). This UE context / UE configuration is used by the source DU for the initial connection with the UE. When the UE moves away from the source DU, the source DU retains at least a part of the information of the UE context / UE configuration while also resetting the information related to at least one protocol layer of the UE context / UE configuration. The reset can include at least one of the following steps: i) RLC re-establishment; ii) creating a "new" tunnel endpoint identifier (TEID) for at least one DRB; iii) maintaining at least one existing TEID; and iv) MAC reset. In some examples, MAC reset may not be applicable to the intra-gNB intra-DU scenario.

[0203] In this way, during the completion phase, the reset of the UE context / resources at the source DU is triggered by the gNB-CU. This trigger can be a message provided by the CU to the source DU indicating that the UE is moving cells. In some examples, this reset is triggered by a message from the target DU. In some examples, the trigger is implicit. In some examples, the trigger will be that the source DU does not receive a message during a predetermined time frame.

[0204] In some examples, the CU initiates the reconstruction or reset of the UE context in the source DU by making changes to at least one F1AP message (such as Figure 5 shown) in the CHO / CPC procedure. Examples of F1AP messages to be changed include: UE context setup request (S503), UE context modification request (S513), UE context modification response (S514), and UE context release request (S515). In other examples, Xn application protocol messages (instead of F1AP messages) are used.

[0205] These examples above will be described in more detail below.

[0206] Figure 6 A signaling diagram between a user equipment and a network entity for service cell change according to a first example is shown.

[0207] In Figure 6 , a trigger for resetting the resources of the UE context at the source DU (also referred to as the source gNB-DU) is included in the UE context release command. When a UE context modification command is received at the source DU, after stopping the downlink data transmission to the UE, the following operations are performed in the source DU: receiving data from the CU-UP to enable early data forwarding, or receiving DL data once the UE moves back to the source DU.

[0208] When an existing user plane (UP) tunnel is reused at the source DU, the existing tunnel is refreshed. A tunnel is a protocol for transmitting data between two network entities. In some examples, these two network entities can be the source DU and the CU. For example, a tunnel can include a transport layer address, a tunnel endpoint identifier, and QoS mapping information to establish a protocol between the two network entities.

[0209] The refreshing of the tunnel includes discarding any data included in the reused tunnel.

[0210] Alternatively, when an existing UP tunnel is not reused at the source DU, new data tunnel resources are created. When a UE context release command is received, the source DU will reset the relevant signaling transmission resources and user data transmission resources. This will be described in more detail below.

[0211] Before S601, it is assumed that the UE is connected to the source DU, whereby uplink and downlink data can be transmitted between the UE and the source DU via the CU. The source DU provides a serving cell for the UE.

[0212] At S601, the UE sends a measurement report message to the source DU / source node (which is also referred to as the source gNB-DU).

[0213] At S602, the source DU sends a UL RRC message transfer message to the CU (which is also referred to as gNB-CU or the second node) to transmit the received measurement report message.

[0214] At S603, the CU sends a UE context setup request message to the target DU (which is also referred to as the target / candidate gNB-DU) to create a UE context and set one or more data bearers. This UE context setup request message is sent to each target / candidate DU. For conditional handover, this UE context setup request message may include "HandoverPreparationInformation". For conditional PSCell change, this UE context setup request message may include "CG-ConfigInfo".

[0215] At S603.1, the UE context setup request message includes an indication that selective activation is enabled. This selective activation is configured by the network (by the CU) such that the UE knows that the provided configuration is for selective activation.

[0216] At S604, the target DU responds to the CU with a UE context setup response message.

[0217] At S605, the CU sends a DL RRC message transfer message to the source DU. This DL RRC message transfer message includes the generated RRCReconfiguration message.

[0218] At S606, the source DU forwards the received RRCReconfiguration message to the UE.

[0219] At S607, the UE responds by providing an RRCReconfigurationComplete message to the source DU.

[0220] At S608, the source DU forwards the RRCReconfigurationComplete message to the CU. This RRCReconfigurationComplete message may be provided in a UL RRC message transfer message.

[0221] At S609, the execution condition for triggering the start of conditional handover or conditional PSCell change is satisfied. For example, the UE measures an A3 event, whereby the target becomes a better offset than the serving cell, or the UE measures an A4 event, whereby the target becomes better than a threshold.

[0222] At S610, a random access procedure is performed between the UE and the target DU. The target DU sends a downlink data transfer status frame to notify the CU. The target DU also sends an "access success" message to the CU to notify the CU which cell the UE has successfully accessed.

[0223] At S611, the UE sends an RRCReconfigurationComplete message to the target DU.

[0224] At S612, the target DU sends a UL RRC message transfer message to the CU. This UL RRC message transfer includes the RRCReconfigurationComplete message.

[0225] At this stage, the DL packets can then be sent from the target DU to the UE. In addition, the uplink packets can be sent from the UE and forwarded by the target DU to the CU.

[0226] At S613, the CU sends a UE context modification request message to the source DU. This UE context modification request message instructs the source DU to stop data transfer with the UE. The source DU sends a DL data transfer status frame to the CU to notify the CU about any DL data that has not been successfully sent to the UE. Any DL packets (such as those including PDCP protocol data units (PDUs)) that have not been successfully sent from the source DU are sent from the CU to the target DU. Subsequently, the target DU can send these DL packets to the UE.

[0227] In some examples, when there is no reuse of the existing UP TNL at the CU, the CU includes a "DRB list to be modified" in the modification request. It can be indicated that the UL UP TNL information included in this UE context modification request message will be applied after the CHO or CPC is completed. In this example, the UP TNL refers to the uplink UP TNL information related to the CU (i.e., the gNB-CU endpoint of the F1 transport bearer used by the DU to transfer UL PDUs to the CU). When the uplink UP TNL information is reused at the CU, the source DU will continue to use the same UP TNL for UL data transfer to the CU.

[0228] In some examples, S613 can occur before S612. Once the CU knows which cell the UE has successfully accessed, S613 can occur as soon as possible.

[0229] In some examples, when selective activation is enabled, the CU does not initiate a UE context release procedure towards any other signaling connection or other target DUs (if any) to cancel conditional handover or conditional PSCell change for the UE. In some scenarios, the CU may initiate a release procedure for other target cells. However, for selective activation, this should be avoided because the preparation is intended to be retained and used by the UE later. Therefore, the resources in the source DU should not be released.

[0230] At S613.1, the UE context modification request message instructs the source DU to retain the configuration information associated with the user equipment and reset the information regarding at least one protocol layer associated with the configuration of the user equipment. The source DU may retain the configuration information so that the source DU can reconnect to the UE more quickly in the future. The UE configuration to be retained can be received at the source DU in a UE context setup request from the CU.

[0231] In one example, the reset includes: when an existing UP tunnel is reused at the source DU, refreshing the existing tunnel to clear any buffered data in the tunnel.

[0232] In one example, when a new UP TNL is to be created, the CU includes a "list of DRBs to be modified" in the UE context modification request message. DL UP TNL information can also be provided in the UE context modification request message. It can be indicated that the DL UP TNL information is to be applied after CHO or CPC is completed. In other words, when the source DU is about to use a new UL UP TNL, the CU sends the "UL UPTNL information" in the "list of UL UPTNL information to be set" (which may be included in the "list of DRBs to be modified") to the source DU.

[0233] The uplink (UL) UP TNL is the CU endpoint of the F1 transport bearer and is used for the transfer of UL protocol data units (PDUs) from the source DU to the CU. The (UL) UP TNL is sent from the CU to the source DU in the UE context modification request.

[0234] The downlink (DL) UP TNL is the source DU endpoint of the F1 transport bearer and is used for the transfer of DL PDUs. The DL UPTNL is sent from the source DU to the CU in the UE context modification response (as discussed below).

[0235] When a UE context modification request is received at the source gNB-DU, when an existing UP tunnel is reused, the source DU refreshes the existing tunnel to clear any buffered data in the tunnel.

[0236] When the UP tunnel is not reused, then: i) the source DU stores the received "DRB list to be modified", and ii) the source DU sends a "modified DRB list" including the new DL UP TNL information in the UE context modification response message (as described below in S614).

[0237] The source DU will apply the received UL UP TNL information after CHO or CPC is completed.

[0238] At S614, the source DU responds to the CU with a UE context modification response message.

[0239] At S614.1, when a new UP TNL is to be created, the "modified DRB list" will include the new DL UP TNL information. This DL UP TNL information can be applied after CHO or CPC is completed. The source DU can provide new "DL UP TNL information" corresponding to the new "UL UP TNL information" received from the CU.

[0240] At S615, the CU sends a UE context release command message to the source DU.

[0241] At S615.1, the UE context release command includes an indication for selective activation. When the UE context release command indicates selective activation, then at S615.2, the information about at least one protocol layer (e.g., MAC) is reset at the source DU. In this way, the UE configuration / context in the source DU is not released / deleted.

[0242] At S615.2, the source DU resets the information about at least one protocol layer associated with the configuration for the UE. The source DU reset can include at least one of the following: RLC reconstruction, creation of a new TEID for the DRB, or maintenance of the existing TEID, MAC reset.

[0243] At S616, the source DU responds to the CU with a UE context release complete message.

[0244] In some examples, one or more of the above Figure 6 steps may not be performed, or may be performed in a different order.

[0245] Figure 7 shows a signaling diagram between a user equipment and a network entity for serving cell change according to a second example;

[0246] In Figure 7 a trigger for resetting the resources of the UE context at the source DU (also referred to as the source gNB-DU) is included in the UE context modification request. In Figure 7Upon receiving a UE context modification request, the source DU releases the signaling transmission resources and user data transmission resources, and performs: i) creating new data tunnel resources, or ii) refreshing the existing tunnels. This will be described in more detail below.

[0247] Before S701, it is assumed that the UE is connected to the source DU, whereby uplink and downlink data can be transmitted between the UE and the source DU via the CU. The source DU provides the serving cell for the UE.

[0248] At S701, the UE sends a measurement report message to the source DU (which is also referred to as the source gNB-DU or source node).

[0249] At S702, the source DU sends a UL RRC message transfer message to the CU (which is also referred to as the gNB-CU or second node or master node) to transfer the received measurement report message.

[0250] At S703, the CU sends a UE context setup request message to the target DU (which is also referred to as the target / candidate gNB-DU or target node) to create a UE context and set one or more data bearers. The UE context setup request message is sent to each target / candidate DU. For conditional handover, the UE context setup request message may include "HandoverPreparationInformation". For conditional PSCell change, the UE context setup request message may include "CG-ConfigInfo".

[0251] At S703.1, the UE context setup request message includes an indication that selective activation is enabled. The selective activation is configured by the network (by the CU) such that the UE knows that the provided configuration is for selective activation.

[0252] At S704, the target DU responds to the CU with a UE context setup response message.

[0253] At S705, the CU sends a DL RRC message transfer message to the source DU. The DL RRC message transfer message includes the generated RRCReconfiguration message.

[0254] At S706, the source DU forwards the received RRCReconfiguration message to the UE.

[0255] At S707, the UE responds by providing a RRCReconfigurationComplete message to the source DU.

[0256] At S708, the source DU forwards the RRCReconfigurationComplete message to the CU. This RRCReconfigurationComplete message can be provided in the UL RRC message transfer message.

[0257] At S709, the execution condition for triggering the start of a conditional handover or a conditional PSCell change is satisfied. For example, the UE measures an A3 event, whereby the target becomes a better offset than the serving cell, or the UE measures an A4 event, whereby the target becomes better than a threshold.

[0258] At S710, a random access procedure is performed between the UE and the target DU. The target DU sends a downlink data transfer status frame to notify the CU. The target DU also sends an "access success" message to the CU to notify the CU which cell the UE has successfully accessed.

[0259] At S711, the UE sends the RRCReconfigurationComplete message to the target DU.

[0260] At S712, the target DU sends a UL RRC message transfer message to the CU. This UL RRC message transfer contains the RRCReconfigurationComplete message.

[0261] At S713, the CU sends a UE context modification request message to the source DU. This UE context modification request message instructs the source DU to stop data transmission with the UE. The source DU sends a DL data transfer status frame to the CU to notify the CU about any DL data that has not been successfully sent to the UE. Any DL packets (e.g., including PDCP protocol data units (PDUs)) that have not been successfully sent from the source DU are sent from the CU to the target DU. Subsequently, the target DU can send these DL packets to the UE.

[0262] At S713.1, this UE context modification request message instructs the source DU to retain the configuration information associated with the user equipment and reset the information about at least one protocol layer associated with the configuration of the user equipment. The source DU can retain the configuration information so that the source DU can reconnect to the UE more quickly in the future.

[0263] The CU can include a "DRB list to be modified" in the UE context modification request. It can be indicated that the UL UP TNL information included in this UE context modification request message will be applied after CHO or CPC is completed.

[0264] In some examples, S713 can occur before S712. Once the CU knows which cell the UE has successfully accessed, S713 can occur as soon as possible.

[0265] At S713.2, upon receiving a UE context modification request, the UE may continue to store the configuration information associated with the UE. The UE may reset or reconstruct the information regarding at least one protocol layer associated with the UE configuration.

[0266] The source DU reset may include at least one of the following: RLC reconstruction, creation of a new TEID for the DRB, or maintenance of an existing TEID, MAC reset.

[0267] At this stage, DL packets may then be sent from the target DU to the UE. Additionally, uplink packets may be sent from the UE and forwarded by the target DU to the CU.

[0268] In one example, the reset includes: when an existing UP tunnel is reused at the source DU, flushing the existing tunnel to clear any buffered data in the tunnel.

[0269] At S714, the source DU responds to the CU with a UE context modification response message.

[0270] At S714.1, the reset includes: storing the received "DRB list to be modified" (from the UE context modification request), and sending a "modified DRB list" including DL UP TNL information in the UE context modification response message. This may occur after CHO or CPC is completed.

[0271] In some examples, one or more of the above Figure 7 steps may not be performed, or may be performed in a different order.

[0272] Figure 8 Shows a signaling diagram between a user equipment and a network entity for serving cell change according to a third example.

[0273] In Figure 8 , a trigger for resources to reset the UE context at the source DU (which is also referred to as the source gNB-DU) is included in the UE context reset request. This UE context reset command is a "new" F1 application protocol (F1AP) message. This UE context reset command is "new" because it is not found in the signaling shown in Figure 5 . Upon receiving this "new" message (which may be referred to as the UE context reset command or any other suitable name), the source DU will reconfigure the signaling transmission resources and data transmission resources, and perform: i) create new data tunnel resources, or ii) flush the existing tunnel. This will be described in more detail below.

[0274] Before S801, it is assumed that the UE is connected to the source DU, whereby uplink and downlink data can be transmitted between the UE and the source DU via the CU. The source DU provides a serving cell for the UE.

[0275] At S801, the UE sends a measurement report message to the source DU (which is also referred to as the source gNB-DU or source node).

[0276] At S802, the source DU sends a UL RRC message transfer message to the CU (which is also referred to as the gNB-CU or second node or master node) to transmit the received measurement report message.

[0277] At S803, the CU sends a UE context setup request message to the target DU (which is also referred to as the target / candidate gNB-DU or target node) to create a UE context and set one or more data bearers. This UE context setup request message is sent to each target / candidate DU. For conditional handover, this UE context setup request message may include "HandoverPreparationInformation". For conditional PSCell change, this UE context setup request message may include "CG-ConfigInfo".

[0278] At S803.1, the UE context setup request message includes an indication that selective activation is enabled. This selective activation is configured by the network (by the CU) so that the UE knows that the provided configuration is for selective activation.

[0279] At S804, the target DU responds to the CU with a UE context setup response message.

[0280] At S805, the CU sends a DL RRC message transfer message to the source DU. This DL RRC message transfer message includes the generated RRCReconfiguration message.

[0281] At S806, the source DU forwards the received RRCReconfiguration message to the UE.

[0282] At S807, the UE responds by providing a RRCReconfigurationComplete message to the source DU.

[0283] At S808, the source DU forwards the RRCReconfigurationComplete message to the CU. This RRCReconfigurationComplete message may be provided in a UL RRC message transfer message.

[0284] At S809, the execution condition for triggering the start of conditional handover or conditional PSCell change is satisfied. For example, the UE measures an A3 event, whereby the target becomes better than the serving cell by an offset, or the UE measures an A4 event, whereby the target becomes better than a threshold.

[0285] At S810, a random access procedure is performed between the UE and the target DU. The target DU sends a downlink data transfer status frame to notify the CU. The target DU also sends an "access success" message to the CU to notify the CU which cell the UE has successfully accessed.

[0286] At S811, the UE sends an RRCReconfigurationComplete message to the target DU.

[0287] At S812, the target DU sends a UL RRC message transfer message to the CU. This UL RRC message transfer contains the RRCReconfigurationComplete message.

[0288] At S813, the CU sends a UE context modification request message to the source DU. This UE context modification request message instructs the source DU to stop data transfer with the UE. The source DU sends a DL data transfer status frame to the CU to notify the CU about any DL data that has not been successfully sent to the UE. Any DL packets (such as including PDCP protocol data units (PDUs)) that have not been successfully sent from the source DU are sent from the CU to the target DU. Subsequently, the target DU can send these DL packets to the UE.

[0289] At this stage, DL packets can subsequently be sent from the target DU to the UE. In addition, uplink packets can be sent from the UE and are forwarded by the target DU to the CU.

[0290] At S814, the source DU responds to the CU with a UE context modification response message.

[0291] At S815, the CU sends a UE context reset command message to the source DU. It should be understood that in other examples, other suitable names are used for the "UE context reset command" message. This UE context reset command is an F1AP message.

[0292] This UE context reset command message can instruct the source DU to retain the configuration information associated with the user equipment and reset the information about at least one protocol layer associated with the user equipment. The source DU can retain the configuration information so that the source DU can reconnect with the UE more quickly in the future.

[0293] At S815.1, the CU indicates that the "modified DRB list" will include DL UP TNL information. It may be indicated that the DL UP TNL information included in this UE context reset command message will be applied after the CHO or CPC is completed.

[0294] At S815.2, the source DU retains the configuration information associated with the UE. The source DU resets the information regarding at least one protocol layer associated with the UE configuration.

[0295] In some examples, upon receiving this UE context reset command message, the source DU will reconfigure the signaling transmission resources and data transmission resources, and / or perform: i) create new data tunnel resources, or ii) refresh the existing tunnels.

[0296] The source DU reset may include at least one of the following: RLC re-establishment, creation of a new TEID for a DRB, or maintenance of an existing TEID, MAC reset.

[0297] When the existing UP tunnel is reused upon receiving the UE context reset command at the source DU, the source DU refreshes the existing tunnel to clear any buffered data in the tunnel.

[0298] When the UP tunnel is not reused, then: i) the source DU stores the received "DRB list to be modified", and ii) the source DU sends the "modified DRB list" including the new DL UP TNL information in the UE context reset completion message (as described below in S816).

[0299] At S816, the source DU sends a UE context reset completion message to the CU.

[0300] At S816.1, the source DU also sends the "modified DRB list" to the CU, which includes the DL UP TNL information associated with the UE that will be applied after the CHO or CPC is completed. The "modified DRB list" may be included in the UE context reset completion message.

[0301] In some examples, Figure 8 one or more of the above steps may not be performed, or may be performed in a different order.

[0302] Although Figures 6 to 8 the examples in show conditional handover and conditional serving cell change, these mechanisms equally apply to non-conditional handover and serving cell change.

[0303] In a fourth example for serving cell change, a trigger is provided for resetting resources of the UE context (with TNL modification) at the source DU using a UE context release command. When a UE context release command is received at the source DU, the following is performed: i) create new data tunnel resources, or ii) refresh existing tunnels. Additionally, when the UE context release command is received, the source DU will reset the associated signaling transmission resources and user data transmission resources (while retaining configuration information associated with the UE). The source DU may send a "modified DRB list" to the CU, which includes DL UP TNL information associated with the UE. This "modified DRB list" may be included in the UE context release complete message.

[0304] As previously mentioned, when a handover or serving cell change occurs, the UE moves from the source cell to the target cell. When the UE has successfully moved to the target cell, the information related to the UE stored at the DU providing the source cell is typically deleted (or a similar operation). Therefore, if the UE is going to move back to the source cell, a further configuration process will have to be performed to connect the UE to the source cell, which takes time. One or more of the above examples illustrate a partial release of the UE context at the source DU after the serving cell change is executed. This enables the UE to return to the same DU without any additional reconfiguration. This is achieved via an indication from the CU to the source DU, which indicates to maintain configuration information (such as transport layer resources) related to the UE, but release and re-prepare / reset other configurations of the UE (such as, for example, MAC and RLC buffers). In this way, the UE can reconnect to the same DU (source DU) more quickly.

[0305] Figure 9 An example method flow executed by one device is shown. In some examples, the device may be used for a source node. In some examples, the device may be included in the source node. In some examples, the device may be the source node. In some examples, the source node is one of the following: gNB, source distributed unit, and source gNB.

[0306] In S901, the method includes communicating with a user equipment, where the user equipment is served by a serving cell provided by the source node.

[0307] In S903, the method includes receiving an indication that the user equipment is moving from the serving cell to a target cell.

[0308] In S905, the method includes, based on the received indication, performing the following operations: i) retain configuration information associated with the configuration for the user equipment, and ii) reset information regarding at least one protocol layer associated with the configuration for the user equipment.

[0309] Figure 10 An example method flow executed by another device is shown. In some examples, the another device can be used for a second node. In some examples, the another device can be included in the second node. In some examples, the another device can be the second node. In some examples, the second node is one of the following: a central unit, a master node, a gNB central unit.

[0310] In S1001, the method includes communicating with a user equipment via a source node, where the user equipment is served by a serving cell provided by the source node.

[0311] In S1003, the method includes providing an indication to the source node that the user equipment is moving from the serving cell to a target cell, where the indication is for the source node: i) to retain configuration information associated with the configuration for the user equipment, and ii) to reset information about at least one protocol layer associated with the configuration for the user equipment.

[0312] Figure 11 A schematic representation of non-volatile storage media 1100a (e.g., Blu-ray Disc (BD), computer disc (CD), or digital versatile disc (DVD)) and 1100b (e.g., solid state drive (SSD), universal serial bus (USB) memory stick) that store instructions and / or parameters 1102 which, when executed by a processor, allow the processor to execute Figure 9 and Figure 10 one or more steps of the method) is shown.

[0313] Note that although example embodiments are described above, several variations and modifications can be made to the disclosed solutions without departing from the scope of the present invention.

[0314] Accordingly, examples can vary within the scope of the appended claims. In general, some embodiments can be implemented using hardware or dedicated circuits, software, logic, or any combination thereof. For example, some aspects can be implemented using hardware, while other aspects can be implemented using firmware or software executable by a controller, microprocessor, or other computing device, but the embodiments are not limited thereto. Although various embodiments can be illustrated and described as block diagrams, flowcharts, or using some other graphical representation, it is fully understood that, by way of non-limiting example, the blocks, devices, systems, techniques, or methods described herein can be implemented using hardware, software, firmware, dedicated circuits or logic, general hardware or a controller or other computing device, or some combination thereof.

[0315] Examples can be implemented by computer software stored in a memory and executable by at least one data processor of the entity involved, or by hardware, or by a combination of software and hardware. In this regard, it should be noted that any process can represent program steps, or interconnected logic circuits, blocks, and functions, or a combination of program steps and logic circuits, blocks, and functions. The software can be stored on physical media such as: storage chips, or storage blocks implemented within a processor, magnetic media (such as hard disks or floppy disks), and optical media (such as, for example, DVDs and their data variants, CDs).

[0316] As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., tangible, rather than a signal), rather than a limitation on the persistence of data storage (e.g., RAM versus ROM).

[0317] As used herein, "at least one of the following: <list of two or more elements / components>" and "at least one of the following: <list of two or more elements / components>" and similar phrases (where the list of two or more elements / components is joined by "and" or "or") mean at least any one of the elements / components, or at least any two or more of the elements / components, or at least all of the elements / components.

[0318] The memory can be of any type suitable for the local technical environment and can be implemented using any suitable data storage technology, such as semiconductor-based storage devices, magnetic storage devices and systems, optical storage devices and systems, fixed memory, and removable memory. The data processor can be of any type suitable for the local technical environment and, by way of non-limiting example, can include one or more of the following: general-purpose computers, dedicated computers, microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), gate-level circuits, and processors based on multi-core processor architectures.

[0319] Alternatively or additionally, some examples can be implemented using circuitry. The circuitry can be configured to perform one or more of the functions and / or method steps described previously. The circuitry can be provided in a base station and / or a communication device.

[0320] As used in this application, the term "circuit" may refer to one or more or all of the following: (a) only hardware circuit implementations (such as only analog and / or digital circuit implementations); (b) a combination of hardware circuits and software, such as: (i) a combination of analog and / or digital hardware circuits and software / firmware; and (ii) any part of a hardware processor (including a digital signal processor), software, and memory with software, which work together to enable a device such as a communication device or a base station to perform the various functions described previously; and (c) a hardware circuit and / or a processor, such as a microprocessor or a part of a microprocessor, which requires software (e.g., firmware) to operate but may be without software when the operation does not require software.

[0321] This definition of "circuit" applies to all uses of the term in this application (including in any claims). As another example, as used in this application, the term "circuit" also encompasses implementations of only hardware circuits or processors (or multiple processors) or a part of a hardware circuit or processor and its accompanying software and / or firmware. The term "circuit" also encompasses, for example, integrated devices / components.

[0322] The foregoing description has provided a complete and informative description of some embodiments by way of illustrative and non-limiting examples. However, various modifications and adaptations may become apparent to those skilled in the relevant art in view of the foregoing description when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar teachings of modifications will still fall within the scope defined by the appended claims.

Claims

1. An apparatus, comprising: means for communicating with a user equipment, wherein the user equipment is served by a serving cell provided by a source node; means for receiving an indication that the user equipment is moving from the serving cell to a target cell; and means for performing the following operations based on the received indication: i) retaining configuration information associated with a configuration for the user equipment, and ii) resetting information regarding at least one protocol layer associated with the configuration for the user equipment.

2. The apparatus according to claim 1, wherein the apparatus comprises: means for reconnecting with the user equipment using the configuration information associated with the user equipment such that the user equipment is served by a cell of the source node.

3. The apparatus according to claim 1 or claim 2, wherein the configuration information associated with the configuration for the user equipment to be retained is received in a user equipment context setup request message.

4. The apparatus according to any one of claims 1 to 3, wherein the configuration information includes user plane transport network layer information associated with the user equipment.

5. The apparatus according to any one of claims 1 to 4, wherein the means for resetting information regarding at least one protocol layer comprises: means for resetting resources associated with the configuration for the user equipment.

6. The apparatus according to any one of claims 1 to 5, wherein the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

7. The apparatus according to any one of claims 1 to 6, wherein the means for resetting information regarding at least one protocol layer comprises at least one of the following: means for resetting signaling transport resources associated with the configuration for the user equipment; means for resetting user data transport resources associated with the configuration for the user equipment; means for performing radio link control re-establishment associated with the configuration for the user equipment; means for performing media access control reset associated with the configuration for the user equipment; means for creating at least one tunnel endpoint identifier for at least one data radio bearer associated with the configuration for the user equipment; means for maintaining at least one existing tunnel endpoint identifier associated with the configuration for the user equipment.

8. The apparatus according to claim 7, wherein the means for maintaining at least one existing tunnel endpoint identifier comprises: means for refreshing an existing tunnel associated with the tunnel endpoint identifier.

9. The apparatus according to claim 7, wherein the means for creating at least one tunnel endpoint identifier comprises: means for determining resources for a tunnel associated with the at least one tunnel endpoint identifier.

10. The apparatus according to claim 7, wherein the means for creating a tunnel endpoint identifier for at least one data radio bearer associated with the user equipment comprises: A component for receiving the uplink user plane transport network layer information with the said indication from a centralized unit; and A component for applying the uplink user plane transport network layer information after the user equipment has moved from the serving cell to the target cell.

11. The apparatus according to claim 10, wherein, the uplink user plane transport network layer information is included in the data radio bearer list to be modified.

12. The apparatus according to any one of claims 1 to 11, wherein, the indication is received in one of the following: F1 application protocol message, and Xn application protocol message.

13. The apparatus according to claim 12, wherein, the F1 application protocol message is one of the following: user equipment context modification request message, user equipment context release command message, and user equipment context reset request message.

14. The apparatus according to any one of claims 1 to 13, wherein, the indication is received from a second node.

15. The apparatus according to claim 14, wherein, the second node is one of the following: centralized unit, master node, target node, gNodeB centralized unit.

16. The apparatus according to any one of claims 1 to 15, wherein, one of the following: the apparatus is for the source node, the apparatus is included in the source node, and the apparatus is the source node.

17. The apparatus according to claim 16, wherein, the source node is one of the following: gNodeB, source distributed unit, and source gNodeB.

18. An apparatus, comprising: A component for communicating with a user equipment via a source node, wherein the user equipment is served by a serving cell provided by the source node; and A component for providing an indication to the source node that the user equipment is moving from the serving cell to a target cell, wherein the indication is for the source node: i) to retain configuration information associated with the configuration for the user equipment, and ii) to reset information about at least one protocol layer associated with the configuration for the user equipment.

19. The apparatus according to claim 18, wherein, the apparatus comprises: A component for receiving, from the source node, signaling for reconnecting with the user equipment using the configuration information associated with the user equipment so that the user equipment is served by a cell of the source node.

20. The apparatus according to claim 18 or claim 19, wherein, the apparatus comprises: A component for providing, in a user equipment context setup request message, the configuration for the user equipment to be retained to the source node.

21. The apparatus according to any one of claims 18 to 20, wherein, the configuration information includes user plane transport network layer information associated with the user equipment.

22. The apparatus according to any one of claims 18 to 21, wherein, the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

23. The apparatus according to any one of claims 18 to 22, wherein, the apparatus comprises: means for providing the source node with the uplink user plane transport network layer information with the indication, wherein the source node is instructed to apply the uplink user plane transport network layer information after the user equipment has moved from the serving cell to the target cell.

24. The apparatus according to claim 23, wherein, the uplink user plane transport network layer information is included in the data radio bearer list to be modified.

25. The apparatus according to any one of claims 18 to 24, wherein, the indication is provided in one of the following: F1 application protocol message, and Xn application protocol message.

26. The apparatus according to claim 25, wherein, the F1 application protocol message is one of the following: user equipment context modification request message, user equipment context release command message, and user equipment context reset request message.

27. The apparatus according to any one of claims 18 to 26, wherein, one of the following: the apparatus is for a second node, the apparatus is included in the second node, and the apparatus is the second node.

28. The apparatus according to claim 27, wherein, the second node is one of the following: central unit, master node, gNodeB central unit.

29. A method, comprising: communicating with a user equipment, wherein the user equipment is served by a serving cell provided by a source node; receiving an indication that the user equipment is moving from the serving cell to a target cell; and based on the received indication, performing the following operations: i) retaining configuration information associated with the configuration for the user equipment, and ii) resetting information about at least one protocol layer associated with the configuration for the user equipment.

30. The method according to claim 29, wherein, the method comprises: reconnecting with the user equipment using the configuration information associated with the user equipment such that the user equipment is served by a cell of the source node.

31. The method according to claim 29 or claim 30, wherein, the configuration information associated with the configuration for the user equipment to be retained is received in a user equipment context setup request message.

32. The method according to any one of claims 29 to 31, wherein, the configuration information includes user plane transport network layer information associated with the user equipment.

33. The method according to any one of claims 29 to 32, wherein, resetting information about at least one protocol layer includes: resetting resources associated with the configuration for the user equipment.

34. The method according to any one of claims 29 to 33, the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

35. The method according to any one of claims 29 to 34, wherein, Resetting information regarding at least one protocol layer includes at least one of the following: Resetting signaling transmission resources associated with the configuration for the user equipment; Resetting user data transmission resources associated with the configuration for the user equipment; Performing radio link control re-establishment associated with the configuration for the user equipment; Performing media access control reset associated with the configuration for the user equipment; Creating at least one tunnel endpoint identifier for at least one data radio bearer associated with the configuration for the user equipment; Maintaining at least one existing tunnel endpoint identifier associated with the configuration for the user equipment.

36. The method according to claim 35, wherein, maintaining at least one existing tunnel endpoint identifier includes: Refreshing an existing tunnel associated with the tunnel endpoint identifier.

37. The method according to claim 35, wherein, creating at least one tunnel endpoint identifier includes: Determining resources for a tunnel associated with the at least one tunnel endpoint identifier.

38. The method according to claim 35, wherein, creating a tunnel endpoint identifier for at least one data radio bearer associated with the user equipment includes: Receiving uplink user plane transport network layer information with the indication from a central unit; and Applying the uplink user plane transport network layer information after the user equipment has moved from the serving cell to the target cell.

39. The method according to claim 38, wherein, the uplink user plane transport network layer information is included in a list of data radio bearers to be modified.

40. The method according to any one of claims 29 to 39, wherein, the indication is received in one of the following: F1 application protocol message, and Xn application protocol message.

41. The method according to claim 40, wherein, the F1 application protocol message is one of the following: user equipment context modification request message, user equipment context release command message, and user equipment context reset request message.

42. The method according to any one of claims 29 to 41, wherein, the indication is received from a second node.

43. The method according to claim 42, wherein, the second node is one of the following: central unit, master node, target node, gNodeB central unit.

44. The method according to any one of claims 29 to 43, wherein, the method is performed by the source node.

45. The method according to claim 44, wherein, the source node is one of the following: gNodeB, source distributed unit, and source gNodeB.

46. A method, comprising: Communicating with a user equipment via a source node, wherein the user equipment is served by a serving cell provided by the source node; and Providing an indication to the source node that the user equipment is moving from the serving cell to a target cell, wherein the indication is for the source node: i) Retain configuration information associated with the configuration for the user equipment, and ii) Reset information about at least one protocol layer associated with the configuration for the user equipment.

47. The method according to claim 46, wherein, the method comprises: Receiving, from the source node, signaling to reconnect with the user equipment using the configuration information associated with the user equipment such that the user equipment is served by a cell of the source node.

48. The method according to claim 46 or claim 47, wherein, the method comprises: Providing, in a user equipment context setup request message, to the source node the configuration for the user equipment to be retained.

49. The method according to any one of claims 46 to 48, wherein, the configuration information includes user plane transport network layer information associated with the user equipment.

50. The method according to any one of claims 46 to 49, the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

51. The method according to any one of claims 46 to 50, wherein, the method comprises: Providing to the source node uplink user plane transport network layer information with the indication, wherein the source node is instructed to apply the uplink user plane transport network layer information after the user equipment has moved from the serving cell to the target cell.

52. The method according to claim 51, wherein, the uplink user plane transport network layer information is included in a list of data radio bearers to be modified.

53. The method according to any one of claims 46 to 52, wherein, the indication is provided in one of the following: F1 application protocol message, and Xn application protocol message.

54. The method according to claim 53, wherein, the F1 application protocol message is one of the following: user equipment context modification request message, user equipment context release command message, and user equipment context reset request message.

55. The method according to any one of claims 46 to 54, wherein, the method is performed by a second node.

56. The method according to claim 55, wherein, the second node is one of the following: central unit, master node, gNodeB central unit.

57. An apparatus, comprising: At least one processor, and at least one memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: Communicate with a user equipment, wherein the user equipment is served by a serving cell provided by a source node; Receive an indication that the user equipment is moving from the serving cell to a target cell; and Based on the received indication, perform the following operations: i) Retain configuration information associated with the configuration for the user equipment, and ii) Reset information about at least one protocol layer associated with the configuration for the user equipment.

58. The apparatus according to claim 57, wherein, cause the apparatus to perform: Reconnect with the user equipment using the configuration information associated with the user equipment so that the user equipment is served by the cell of the source node.

59. The apparatus according to claim 57 or claim 58, wherein, the configuration information associated with the configuration for the user equipment to be retained is received in a user equipment context setup request message.

60. The apparatus according to any one of claims 57 to 59, wherein, the configuration information includes user plane transport network layer information associated with the user equipment.

61. The apparatus according to any one of claims 57 to 60, wherein, resetting the information about at least one protocol layer includes: resetting the resources associated with the configuration for the user equipment.

62. The apparatus according to any one of claims 57 to 61, wherein the indication includes a further indication to maintain the transport layer resources associated with the configuration for the user equipment.

63. The apparatus according to any one of claims 57 to 62, wherein, resetting the information about at least one protocol layer includes at least one of the following: resetting the signaling transport resources associated with the configuration for the user equipment; resetting the user data transport resources associated with the configuration for the user equipment; performing radio link control re-establishment associated with the configuration for the user equipment; performing media access control reset associated with the configuration for the user equipment; creating at least one tunnel endpoint identifier for at least one data radio bearer associated with the configuration for the user equipment; maintaining at least one existing tunnel endpoint identifier associated with the configuration for the user equipment.

64. The apparatus according to claim 63, wherein, maintaining at least one existing tunnel endpoint identifier includes: refreshing the existing tunnel associated with the tunnel endpoint identifier.

65. The apparatus according to claim 63, wherein, creating at least one tunnel endpoint identifier includes: determining the resources for the tunnel associated with the at least one tunnel endpoint identifier.

66. The apparatus according to claim 63, wherein, creating a tunnel endpoint identifier for at least one data radio bearer associated with the user equipment includes: receiving uplink user plane transport network layer information with the indication from a centralized unit; and applying the uplink user plane transport network layer information after the user equipment has moved from the serving cell to the target cell.

67. The apparatus according to claim 66, wherein, the uplink user plane transport network layer information is included in a list of data radio bearers to be modified.

68. The apparatus according to any one of claims 57 to 67, wherein, the indication is received in one of the following: F1 application protocol message, and Xn application protocol message.

69. The apparatus according to claim 68, wherein, The F1 application protocol message is one of the following: a user equipment context modification request message, a user equipment context release command message, and a user equipment context reset request message.

70. The apparatus according to any one of claims 57 to 69, wherein, the indication is received from a second node.

71. The apparatus according to claim 70, wherein, the second node is one of the following: a central unit, a master node, a target node, a gNodeB central unit.

72. The apparatus according to any one of claims 57 to 71, wherein, one of the following: the apparatus is for the source node, the apparatus is included in the source node, and the apparatus is the source node.

73. The apparatus according to claim 72, wherein, the source node is one of the following: a gNodeB, a source distributed unit, and a source gNodeB.

74. An apparatus, comprising: at least one processor, and at least one memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: communicate with a user equipment via a source node, wherein the user equipment is served by a serving cell provided by the source node; and provide to the source node an indication that the user equipment is moving from the serving cell to a target cell, wherein the indication is for the source node: i) retain configuration information associated with the configuration for the user equipment, and ii) reset information about at least one protocol layer associated with the configuration for the user equipment.

75. The method according to claim 74, wherein, the method includes: receive from the source node signaling to reconnect with the user equipment using the configuration information associated with the user equipment such that the user equipment is served by a cell of the source node.

76. The method according to claim 74 or claim 75, wherein, the method includes: provide to the source node in a user equipment context setup request message the configuration to be retained for the user equipment.

77. The method according to any one of claims 74 to 76, wherein, the configuration information includes user plane transport network layer information associated with the user equipment.

78. The method according to any one of claims 74 to 77, the indication includes a further indication to maintain transport layer resources associated with the configuration for the user equipment.

79. The method according to any one of claims 74 to 78, wherein, the method includes: provide to the source node uplink user plane transport network layer information with the indication, wherein the source node is instructed to apply the uplink user plane transport network layer information after the user equipment has moved from the serving cell to the target cell.

80. The method according to claim 7, wherein, the uplink user plane transport network layer information is included in a data radio bearer list to be modified.

81. The method according to any one of claims 74 to 80, wherein, The indication is provided in one of the following: an F1 application protocol message, and an Xn application protocol message.

82. The method according to claim 81, wherein, the F1 application protocol message is one of the following: a user equipment context modification request message, a user equipment context release command message, and a user equipment context reset request message.

83. The method according to any one of claims 74 to 82, wherein, the method is executed by a second node.

84. The method according to claim 83, wherein, the second node is one of the following: a central unit, a master node, a gNodeB central unit.

85. A computer program comprising instructions which, when executed by a device, cause the device to perform at least the following operations: communicate with a user equipment, wherein, the user equipment is served by a serving cell provided by a source node; receive an indication that the user equipment is moving from the serving cell to a target cell; and based on the received indication, perform the following operations: i) retain configuration information associated with a configuration for the user equipment, and ii) reset information regarding at least one protocol layer associated with the configuration for the user equipment.

86. A computer program comprising instructions which, when executed by a device, cause the device to perform at least the following operations: communicate with a user equipment via a source node, wherein, the user equipment is served by a serving cell provided by the source node; and provide to the source node an indication that the user equipment is moving from the serving cell to a target cell, wherein the indication is for the source node to: i) retain configuration information associated with a configuration for the user equipment, and ii) reset information regarding at least one protocol layer associated with the configuration for the user equipment.

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