Handover to RRC connected state

Abstract

A method includes receiving, by a first device from a second device, a first message indicating that a user equipment (UE) is requested to switch to an RRC connected state for which a small data transmission (SDT) procedure is ongoing in a radio resource control (RRC) inactive state involving the user equipment, the first device, and the second device. The first apparatus generates an RRC setup message based on indicating that the UE is requested to switch to the RRC connected state, and transmits the RRC setup message to the UE in the RRC inactive state.

Description

Technical Field

[0001] The various example embodiments generally relate to wireless networks, and more specifically to the rapid recovery from the small data transmission (SDT) state to the connected state. Background Technology

[0002] Small Data Transfer (SDT) is a process of maintaining a Radio Resource Control (RRC_INACTIVE) state (e.g., not transitioning to RRC connected state) while allowing data and / or signaling transmission. SDT is enabled on a radio bearer basis and is initiated by the User Equipment (UE) depending on several factors (e.g., less than the configured uplink (UL) data volume awaiting transmission across all radio bearers for which SDT is enabled, downlink reference signal received power (DL RSRP) exceeding a configured threshold, and / or available effective SDT resources). However, in each case, the UE may need to switch from RRC inactive state to RRC connected state for communication. Summary of the Invention

[0003] In one aspect of this disclosure, a method includes: a first device receiving a first message from a second device, the first message indicating that a user equipment (UE) has been requested to switch to an RRC connected state, for which a small data transmission (SDT) process is underway in a Radio Resource Control (RRC) inactive state involving the UE, the first device, and the second device. The first device generates an RRC establishment message based on the indication that the UE has been requested to switch to the RRC connected state and sends the RRC establishment message to the UE in the RRC inactive state.

[0004] In one aspect of the method, the first message is the Xn Application Protocol (XnAP) retrieve UE context response message.

[0005] In one aspect of the method, instructing the UE to be requested to switch to RRC connected state includes at least one of the following: instructing the end of the SDT process, instructing that the downlink data size in the buffer exceeds the data size used for SDT transmission, instructing that non-SDT transmission will be sent, or instructing a request or need to switch to RRC connected state.

[0006] In one aspect of the method, the first message is received based on the following: the amount of uplink SDT data exceeds a threshold, or non-SDT data will be sent.

[0007] In one aspect of the method, the first message is received based on an RRC message from the user equipment to the second device, which indicates that the amount of uplink SDT data exceeds a threshold or that uplink non-SDT data will be sent.

[0008] In one aspect of the method, non-SDT transmission is used for transmission on radio bearers that are not configured for SDT transmission.

[0009] In one aspect of the method, the first device generates an RRC establishment message that includes an instruction received from the second device.

[0010] In one aspect of the method, the first device is the receiving gNodeB involved in the SDT process.

[0011] In one aspect of the method, the second device is the anchor gNodeB involved in the SDT process.

[0012] In one aspect of the method, the method includes: after sending an RRC establishment message to the UE, receiving a third message from the UE by a first device.

[0013] In one aspect of the method, the third message is the RRC establishment completion message.

[0014] In one aspect of the method, the method includes: receiving an RRC release message included in a first message by a first device, and determining at least one of the following: terminating the SDT transaction and sending the RRC release message to the UE, or switching the UE to an RRC connection state and generating an RRC establishment message and sending the RRC establishment message to the UE.

[0015] In one aspect of the method, the RRC establishment message causes the UE to move to the RRC connected state.

[0016] In one aspect of this disclosure, a method includes: receiving, by a second device, an indication from a user equipment (UE) in an RRC message or from a first device in an XnAP message, the indication indicating that the amount of uplink small data transfer (SDT) data exceeds a threshold or that uplink non-SDT data is to be transmitted by the UE. The second device determines, based on the received message, to switch the UE from an RRC inactive state to an RRC connected state, and sends a first message to the first device indicating that the UE is requested to switch to the RRC connected state, for which an SDT process is underway in the RRC inactive state involving the UE, the first device, and the second device.

[0017] In one aspect of this disclosure, a first device includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first device to perform at least any of the aforementioned methods.

[0018] In one aspect of this disclosure, a second apparatus includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to perform at least any of the aforementioned methods.

[0019] In one aspect of this disclosure, a processor-readable medium stores instructions that, when executed by at least one processor of the device, cause the device to perform at least any of the aforementioned methods.

[0020] In one aspect of this disclosure, a first apparatus includes: a memory; and a processor operatively coupled to and communicating with the memory. The processor is configured to: receive a first message from a second apparatus indicating that a user equipment (UE) has been requested to switch to an RRC connected state, for which a small data transfer (SDT) process is underway in a Radio Resource Control (RRC) inactive state involving the UE, the first apparatus, and the second apparatus; generate an RRC establishment message based on the indication that the UE has been requested to switch to the RRC connected state; and send the RRC establishment message to the UE in the RRC inactive state.

[0021] In one aspect of this disclosure, a second device includes: a memory; and a processor operatively coupled to and communicating with the memory, the processor being configured to: receive an indication from a user equipment in an RRC message or from a first device in an XnAP message, the indication indicating that the amount of uplink small data transfer (SDT) data exceeds a threshold or that uplink non-SDT data is to be transmitted by the user equipment; determine, based on the received message, to switch the user equipment from an RRC inactive state to an RRC connected state; and send a first message to the first device indicating that the user equipment is requested to switch to an RRC connected state, for which an SDT process is in progress in an RRC inactive state involving the user equipment, the first device, and the second device.

[0022] The independent claims provide the subject matter for several aspects. Additional aspects are defined in the dependent claims. Attached Figure Description

[0023] Some exemplary embodiments will now be described with reference to the accompanying drawings.

[0024] Figure 1 This is a diagram illustrating an example embodiment of wireless networking between a network system and a user equipment (UE) according to one aspect of this disclosure; Figure 2 This is a diagram illustrating an example component of a network system according to an aspect of this disclosure; Figure 3 This is an illustration of an example embodiment of signals and operations between the UE, the receiving gNB, the anchor gNB, and the UPF, according to one aspect of this disclosure; and Figure 4 This is a diagram illustrating an example embodiment of a component of a UE or network device according to one aspect of this disclosure. Detailed Implementation

[0025] In the following description, certain specific details are set forth in order to provide a thorough understanding of the disclosed aspects. However, those skilled in the art will recognize that the aspects can be practiced without one or more of these specific details or using other methods, components, materials, etc. In other instances, well-known structures associated with transmitters, receivers, or transceivers have not been shown or described in detail to avoid unnecessarily obscuring the description of the aspects.

[0026] Throughout this specification, the reference to "an aspect" or "aspect" means that a particular feature, structure, or characteristic described in connection with that aspect is included in at least one aspect. Therefore, the phrases "in an aspect" or "in one respect" appearing in various places throughout this specification do not necessarily refer to the same aspect. Furthermore, a particular feature, structure, or characteristic may be combined in one or more aspects in any suitable manner.

[0027] The embodiments described in this disclosure can be implemented in wireless networking devices, such as, but not limited to, devices utilizing: Global Microwave Access Interoperability (WiMAX), Global System for Mobile Communications (GSM, 2G), GSM EDGE Radio Access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunications System based on Basic Wideband Code Division Multiple Access (W-CDMA) (UMTS, 3G), High-Speed ​​Packet Access (HSPA), Long Term Evolution (LTE), Advanced LTE, Enhanced LTE (eLTE), 5G New Radio (5G NR), 5G Advanced, 6G (and above), and 802.11ax (Wi-Fi 6), and other wireless networking systems. The term "eLTE" here refers to LTE evolution connected to a 5G core. LTE is also referred to as Evolved UMTS Terrestrial Radio Access (EUTRA) or Evolved UMTS Terrestrial Radio Access Network (EUTRAN).

[0028] This disclosure may use the term "serving network device" to refer to a network node or network device (or part thereof) serving a UE. As used herein, the terms "send to," "receive from," and "cooperate with" (and variations thereof) include communication that may or may not involve communication through one or more intermediate devices or nodes. The term "acquire" (and variations thereof) includes acquiring in a first instance or reacquiring after a first instance. The term "connection" may refer to a physical connection or a logical connection.

[0029] This disclosure uses 5G NR as an example of a wireless network, and may use smartphones and / or extended reality headsets as examples of UEs. It is intended and should be understood that such examples are merely illustrative, and this disclosure applies to other wireless networks and user equipment.

[0030] Figure 1 This is a diagram illustrating an example of wireless networking between network system 100 and user equipment (UE) 150. Network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network devices 130 (e.g., test equipment). Network node 120 will be described in more detail below. As used herein, the term "network apparatus" may refer to any component of network system 100, such as server 110, network node 120, network device 130, any of the foregoing components, and / or any other component of network system 100. Examples of network apparatus include, but are not limited to, apparatuses for implementing various aspects of 5G NR. This disclosure describes embodiments related to 5G NR and embodiments relating to aspects defined by the 3rd Generation Partnership Project (3GPP). However, it is contemplated that embodiments related to other wireless networking technologies are included within the scope of this disclosure.

[0031] The following description provides further details of examples of network nodes. In a 5G NR network, a gNodeB (also known as a gNB) may include, for example, a node that provides the UE with New Radio (NR) user plane and control plane protocol termination and connects to the 5G core (5GC) via an NG interface, as exemplified by Section 3.2 of 3GPP TS 38.300 V16.6.0 (2021-06), which is incorporated herein by reference.

[0032] gNB supports various protocol layers, such as Layer 1 (L1) - the physical layer, Layer 2 (L2) and Layer 3 (L3).

[0033] NR's Layer 2 (L2) is divided into the following sublayers: Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and Service Data Adaptation Protocol (SDAP), among which, for example: ○ The physical layer provides a transmission channel to the MAC sublayer; ○ The MAC sublayer provides logical channels to the RLC sublayer; ○ The RLC sublayer provides RLC channels to the PDCP sublayer; ○ The PDCP sublayer provides radio bearers to the SDAP sublayer; ○ The SDAP sublayer provides Quality of Service (QoS) flows to 5GC; ○ The control channels include the Broadcast Control Channel (BCCH) and the Physical Control Channel (PCCH).

[0034] Layer 3 (L3) includes, for example, Radio Resource Control (RRC) according to Section 6 of 3GPP TS 38.300 V16.6.0 (2021-06), which is incorporated herein by reference.

[0035] The gNB Central Unit (gNB-CU) comprises logical nodes that host the gNB's Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) protocols, or the en-gNB's RRC and PDCP protocols, and controls the operation of one or more gNB Distributed Units (gNB-DUs). The gNB-CU terminates the F1 interface connected to the gNB-DU. The gNB-CU may also be referred to herein as a CU, Central Unit, Centralized Unit, or Control Unit.

[0036] A gNB Distributed Unit (gNB-DU) comprises, for example, a logical node hosting a gNB or en-gNB at the Radio Link Control (RLC), Media Access Control (MAC), and Physical (PHY) layers, and its operation is partially controlled by the gNB-CU. A gNB-DU supports one or more cells. A cell is supported by only one gNB-DU. The gNB-DU terminates the F1 interface connected to the gNB-CU. The gNB-DU may also be referred to herein as a DU or Distributed Unit.

[0037] As used herein, the term "network node" can refer to any one or any combination of gNB, gNB-CU, or gNB-DU. RAN (Radio Access Network) nodes or network nodes (such as gNB, gNB-CU, or gNB-DU, or portions thereof) can be implemented using means having, for example, at least one processor and / or at least one memory having processor-readable instructions ("programs") configured to support and / or provide and / or process CU and / or DU-related functionalities and / or features, and / or at least one protocol (sub) layer (e.g., layer 2 and / or layer 3) of the RAN (Radio Access Network). Different functional divisions between central and distributed units are possible. The following will combine... Figure 4 Examples describing such devices and components.

[0038] The gNB-CU and gNB-DU portions can be co-located or physically separated, for example. The gNB-DU can even be further divided into, for example, two parts, one including processing equipment and the other including an antenna. The Central Unit (CU) can also be referred to as a Baseband Unit / Radio Equipment Controller / Cloud RAN / Virtual RAN (BBU / REC / C-RAN / V-RAN), Open RAN (O-RAN), or a portion thereof. The Distributed Unit (DU) can also be referred to as a Remote Radio Head / Remote Radio Unit / Radio Equipment / Radio Unit (RRH / RRU / RE / RU), or a portion thereof. In the various exemplary embodiments of this disclosure below, a network node supporting at least one of the Central Unit functions or Layer 3 protocols of a radio access network can be, for example, a gNB-CU. Similarly, a network node supporting at least one of the Distributed Unit functions or Layer 2 protocols of a radio access network can be, for example, a gNB-DU.

[0039] A gNB-CU can support one or more gNB-DUs. A gNB-DU can support one or more cells, thus supporting the serving cell for user equipment (UE) or candidate cells for handover, dual connectivity and / or carrier aggregation and other procedures.

[0040] User equipment (UE) 150 may be or include wireless or mobile devices, devices having a radio interface for interacting with a RAN (Radio Access Network), smartphones, in-vehicle devices, IoT devices, or M2M devices, and other types of user equipment. Such a UE 150 may include: at least one processor; and at least one memory including program code; wherein the at least one memory and the computer program code are configured, together with the at least one processor, to enable the device to perform at least certain operations, such as an RRC connection to the RAN. Figure 4 Examples of components describing a UE are provided below. In an embodiment, UE 150 may be configured to generate messages to be transmitted to the RAN via radio (e.g., including a cell ID) (e.g., to reach and communicate with the serving cell). In an embodiment, UE 150 may generate, transmit, and receive RRC messages containing one or more RRC PDUs (Packet Data Units). Those skilled in the art will understand the RRC protocol and other processes that the UE may perform.

[0041] Continue to refer to Figure 1In an example of a 5G NR network, network system 100 provides one or more cells that define the coverage area of ​​network system 100. As described above, network system 100 may include a gNB of the 5G NR network, or may include any other means configured to control radio communications and manage radio resources within the cells. As used herein, the term "resource" may refer to radio resources such as resource blocks (RBs), physical resource blocks (PRBs), radio frames, subframes, time slots, subbands, frequency regions, subcarriers, beams, etc. In embodiments, network node 120 may be referred to as a base station.

[0042] Figure 1 Examples are provided, and only network system 100 and UE 150 are shown. Those skilled in the art will understand that network system 100 includes... Figure 1 Components not shown in the diagram, and it will be understood that other user equipment can communicate with network system 100.

[0043] Figure 2 yes Figure 1 A block diagram of example components of network system 100. A 5G NR network can be described as an example of network system 100, and the aspects described below should also be applicable to other types of network systems. The network system can be configured according to... Figure 1 The signals and connections shown operate to enable UE 150 to communicate with network system 100 via radio access network 225. Additionally, the network system can be divided into user plane components and functions and control plane components and functions, as shown and described herein. Unless otherwise stated, the terms “component,” “function,” and “service” are used interchangeably herein and can refer to instructions executed by and implemented by one or more processors.

[0044] The following describes example functionality of the components. This example functionality is merely illustrative, and it should be understood that additional operations and functions can be performed by the components described herein. Furthermore, connections between components can be virtual connections based on service interfaces, allowing any component to communicate with any other component. In this way, any component can act as a service "producer" for any other component acting as a service "consumer," providing services for network functions.

[0045] For example, a core network 210 is described in the control plane of the network system. The core network 210 may include an Authentication Server Function (AUSF) 211, an Access and Mobility Function (AMF) 212, and a Session Management Function (SMF) 213. The core network 210 may also include a Network Slice Selection Function (NSSF) 214, a Network Open Function (NEF) 215, a Network Repository Function (NRF) 216, and a Unified Data Management Function (UDM) 217, which may include a Unified Data Repository (UDR) 224.

[0046] Additional components and functions of the core network 210 may include application functions 218, policy control functions (PCF) 219, network data analysis functions (NWDAF) 220, analytical data repository functions (ADRF) 221, management data analysis functions (MDAF) 222, and operation and management functions (OAM) 223.

[0047] The user plane includes UE 150, Radio Access Network (RAN) 225, User Plane Function (UPF) 226, and Data Network (DN) 227. RAN 225 may include a combination of Figure 1 The RAN 225 describes one or more components, such as one or more network nodes. However, the RAN 225 may not be limited to such components. The UPF 226 provides connectivity for data transmitted through the RAN 225. For example, the DN 226 identifies services from service providers, internet access, and third-party services.

[0048] AMF 212 handles connectivity and mobility tasks. AUSF 211 receives authentication requests from AMF 212 and interacts with UDM 217 to authenticate and verify network responses to determine successful authentication. SMF 213 performs Packet Data Unit (PDU) session management and manages session context with UPF 226.

[0049] NSSF 214 can select a Network Slice Instance (NSI) and determine the allowed Network Slice Selection Auxiliary Information (NSSAI). This selection and determination are used to set up AMF 212 to provide services to UE 150. NEF 215 ensures third-party access to network services to create private network services. NRF 216 acts as a repository for storing network functions to allow functions to register and discover each other.

[0050] UDM 217 generates authentication vectors for use by AUSF 211 and ADM 212 and provides user identity processing. UDM 217 can connect to UDR 224, which stores data associated with authentication, applications, etc. AF 218 provides application services (e.g., streaming services) to users. PCF 219 provides policy control functions. For example, PCF 219 can assist in network slicing and mobility management, as well as provide Quality of Service (QoS) and accounting functions.

[0051] NWDAF 220 collects data (e.g., from UE 150 and network systems) to perform network analytics and provide insights into the capabilities that leverage analytics when providing services. ADRF 221 allows consumers to store, retrieve, and remove data and analytics. MDAF 222 provides additional data analytics services for network functions. OAM 223 provides provisioning and management processing capabilities to manage elements in or connected to the network (e.g., UE 150, network nodes, etc.).

[0052] Figure 2 These are merely examples of components of a network system, and variations are contemplated within the scope of this disclosure. In embodiments, the network system may include... Figure 2 Other components not shown. In embodiments, the network system may not include... Figure 2 Each component is shown. In embodiments, components and connections can utilize [the following]. Figure 2 The connections shown are implemented using different connections. These and other embodiments are considered to be within the scope of this disclosure.

[0053] Although further details are provided below, as described above, in various embodiments, when operating in a Radio Resource Control (RRC) inactive state, a UE may use a Small Data Transmission (SDT) procedure or multiple SDT procedures to transmit services. A UE operating in an RRC inactive state according to an SDT procedure may transmit data on one or more radio bearers configured for SDT communication.

[0054] As described above, SDT is a process of maintaining an RRC inactive state without transitioning to an RRC connected state while allowing data and / or signaling transmission. In various embodiments, SDT can be enabled on a radio bearer basis and can be initiated by the UE in the case of Mobile Station Initiated SDT (MO-SDT) or by the network in the case of Mobile Station Termination SDT (MT-SDT). In various embodiments, MO-SDT is initiated by the UE if less than a configured amount of UL data awaits transmission across all radio bearers with SDT enabled, the Downlink Reference Signal Received Power (DL RSRP) is higher than a configured threshold, and / or valid SDT resources are available. In various example embodiments, valid SDT resources can be understood as those specified in Clause 5.27.1 of TS 38.321. In various embodiments, MT-SDT can be initiated by the network in a paging message using an indication to the UE while DL data awaits transmission across radio bearers configured for SDT. Based on this indication, the UE can initiate MT-SDT only if the DL RSRP is higher than the configured threshold.

[0055] In various embodiments, the UE may communicate with a serving gNB (e.g., an anchor gNB) that provides SDT communication capabilities to the UE. In various embodiments, the anchor gNB may be the last serving gNB for the UE. In various embodiments, the UE may move and communicate with another gNB (e.g., a receiving gNB). In this case, the anchor gNB may transfer control of the UE to the receiving gNB and provide the receiving gNB with complete context information about the UE. In various embodiments, this may be referred to as "SDT with UE context relocation" according to Section 18.2 of TS 38.300. In various embodiments, the anchor gNB may retain control of the UE and only perform a partial transfer of context information about the UE. In various embodiments, this may be referred to as "SDT without UE context relocation" according to Section 18.3 of TS 38.300.

[0056] In various example embodiments, the UE may need to transition from an RRC inactive state to an RRC connected state. For example, in various embodiments, the anchor gNB may receive non-SDT downlink data to be transmitted (i.e., on a radio bearer not configured for SDT). In various embodiments, the anchor gNB may detect in its buffer a large amount of downlink SDT data to be transmitted that may exceed a threshold for SDT communication (e.g., the amount of downlink data to be sent to the UE exceeds a threshold for SDT communication). In various embodiments, the anchor gNB may receive from the UE an indication that non-SDT uplink data will be transmitted by the UE. In various embodiments, the anchor gNB may receive an indication that a large amount of uplink SDT data is to be transmitted by the UE (e.g., the amount of uplink data to be transmitted by the UE exceeds a threshold for SDT communication).

[0057] Therefore, although further details are provided below, this document provides a procedure for a UE to switch from an RRC inactive state to an RRC connected state during an ongoing SDT request. That is, an SDT procedure may be in progress for a UE that is in an RRC inactive state. In various embodiments, the procedure described herein may involve a UE receiving gNB services with partial context, where the anchor gNB retains control over the UE (referred to as SDT without UE context relocation).

[0058] As used herein, communication with the Radio Access Network (RAN) can refer to and indicate communication with a portion of the RAN (such as with network nodes (e.g., DU and / or CU)) or another portion of the RAN. As used herein, communication with the Core Network can refer to and indicate communication with one or more services / applications of the Core Network (such as AMF or another service of the Core Network).

[0059] As used herein, in various embodiments, the term "receiving gNB" can refer to a gNB currently providing communication to the UE, while the term "anchor gNB" can refer to a gNB acting as a serving gNB communicating with the receiving gNB. In various example embodiments, the terms "apparatus," "first apparatus," "second apparatus," etc., can refer to any apparatus that performs the function of communicating with the UE or another apparatus. In various example embodiments, the term "first apparatus" can refer to the receiving gNB, and the term "second apparatus" can refer to the anchor gNB, and vice versa. In various embodiments, the term "UE" can be used interchangeably with the terms "mobile station" or "MS." For example, in various embodiments, the terms "user equipment" or UE can be used to identify a mobile station or MS connected to the network, or the terms "mobile station" or MS can be used to identify a user equipment or UE connected to the network.

[0060] Based on the brief description, Figure 3This is a diagram illustrating an example embodiment of signals and operations between the UE, receiving gNB, anchor gNB, and UPF, according to one aspect of this disclosure. The following paragraphs will describe various signals and operations. It should be understood that the described signals may have associated operations, and the described operations may have associated signals.

[0061] like Figure 3 As shown, the UE may include, for example: Figure 1 The UE 150 described herein may include network node 120 (in Figure 3 The UPF may include 120a for receiving gNB and 120b for anchoring gNB, and may include Figure 2 UPF226 as described in [the document / reference].

[0062] At operation 301, the UE is in an RRC inactive state. In various exemplary embodiments, the UE may participate in SDT transactions (i.e., SDT procedures involving multiple SDT transmissions), where data is transmitted between the UE and a gNB (e.g., an anchor gNB), as described above. In various embodiments, the SDT procedure may be underway. In various example embodiments, the UE communicates with the receiving gNB, while the anchor gNB maintains control (e.g., service) over the UE.

[0063] Therefore, at operation 302, in order to participate in the SDT procedure, the receiving gNB has previously sent an Xn UE context retrieval request message to the anchor gNB, and the anchor gNB has received the Xn UE context retrieval request message. Upon receiving the Xn UE context retrieval request, at operation 303, the anchor gNB, which expects (e.g., needs) to maintain control over the UE, has sent an Xn partial UE context transfer message to the receiving gNB, and the receiving gNB has received the Xn partial transfer message.

[0064] The Xn partial transfer message includes partial context information relating to communication with the UE. Upon receiving the Xn partial transfer message, at operation 304, the receiving gNB has already sent the Xn partial UE context transfer acknowledgment message to the anchor gNB, and the anchor gNB has already received the Xn partial UE context transfer acknowledgment message. Those skilled in the art will understand that, according to Section 18.3 of TS 38.300, the content of the messages sent at operations 302-304 is used to participate in the SDT procedure known as “No UE Context Relocation”. In various embodiments, operations 302-304 may have already been performed during UE movement, enabling the UE to communicate with the receiving gNB, where the anchor gNB wishes to maintain control and service over the UE.

[0065] Therefore, at operation 305, the UE that has already participated in the SDT process with the anchor gNB as described above continues to communicate with the receiving gNB.

[0066] As described above, the anchor gNB may need to request the UE to switch from an RRC inactive state to an RRC connected state. For example, the anchor gNB may determine that it is requesting the UE to switch from an RRC inactive state to an RRC connected state. For example, in various embodiments, the anchor gNB may receive non-SDT downlink data to be transmitted (i.e., on a radio bearer not configured for SDT). In various embodiments, the anchor gNB may detect that a large amount of downlink SDT data to be transmitted in its buffer may exceed a threshold for SDT communication. In various embodiments, the anchor gNB may receive an indication from the UE that non-SDT uplink data will be transmitted by the UE. In various embodiments, the anchor gNB may receive an indication that a large amount of uplink SDT data will be transmitted by the UE. The anchor gNB may be configured to determine the need for a handover request based on one or more of the above-described triggers (e.g., based on receiving non-SDT downlink data to be transmitted).

[0067] like Figure 3 As shown, in the example embodiment, at operation 306, the UPF sends non-SDT data to the UE's anchor gNB, and the anchor gNB receives the non-SDT data. The reception of the non-SDT data triggers the anchor gNB to request the UE to switch from the RRC inactive state to the RRC connected state. The operation depicted at operation 306 is exemplary, and other conditions may occur that would cause the anchor gNB to request the UE to switch to the RRC connected state. As mentioned above, the anchor gNB may detect that a large amount of downlink SDT data to be transmitted in its buffer may exceed the threshold for SDT communication. In various embodiments, the anchor gNB may receive an indication from the UE that non-SDT uplink data will be transmitted by the UE. In various embodiments, the anchor gNB may receive an indication that a large amount of uplink SDT data will be transmitted by the UE. Therefore, those skilled in the art will understand that operation 306 includes an example of triggering a switch to the RRC connected state, but other conditions may also trigger a switch.

[0068] At operation 307, the anchor gNB sends an Xn Retrieve UE Context Response message (e.g., an Xn Application Protocol (XnAP) Retrieve UE Context Response message) to the receiving gNB, and the receiving gNB receives the Xn Retrieve UE Context Response message. In various embodiments, the Xn Retrieve UE Context Response message includes one or more of the following indications: the end of the SDT procedure, the downlink data size in the buffer exceeds the data size used for SDT transmission (e.g., exceeding a threshold for SDT transmission), a non-SDT transmission will be sent, or a request / expectation to switch to RRC connected state. The Xn Retrieve UE Context Response message may be an example of a first message used in this disclosure.

[0069] Based on a message received from the anchor gNB (e.g., an Xn UE Context Response), the receiving gNB generates an RRC establishment message to be sent to the UE. For example, generating the RRC establishment message may be based on one or more indications included in the message received from the anchor gNB. Typically, the receiving gNB may generate the RRC establishment message based on determining that the UE will switch from an RRC inactive state to an RRC connected state. As an example, upon receiving (or in response to receiving) the Xn UE Context Response message at operation 307, the receiving gNB generates the RRC establishment message at operation 308 based on the indications included in the Xn UE Context Response message. That is, for example, the receiving gNB generates (constructs) an RRC establishment message to send to the UE, and this will cause the UE to switch / transition from an RRC inactive state to an RRC connected state for communication.

[0070] In various embodiments, the anchor gNB can send an RRC release message to the receiving gNB, and the gNB can determine to terminate the SDT transaction process and send an RRC release message to the UE. In various embodiments, the receiving gNB can determine to switch the UE to RRC connected state, and generate an RRC establishment message and send it to the UE.

[0071] Therefore, in various embodiments, at operation 309, the receiving gNB sends an RRC establishment message to the UE, and the UE receives the RRC establishment message. As discussed, the UE may be in an RRC inactive state when it receives the RRC establishment message. Upon receiving the RRC establishment message, at operation 310, the UE sends an RRC establishment complete message to the receiving gNB, and the receiving gNB receives the RRC establishment complete message.

[0072] Therefore, at operation 311, the UE operates in RRC connected mode. Those skilled in the art will understand the procedure for a UE operating in RRC connected mode. That is, an RRC establishment message can switch the UE from RRC inactive mode to RRC connected mode.

[0073] Figure 3 The operations described are merely illustrative and variations are expected within the scope of this disclosure. In embodiments, the operations may include... Figure 3 Other operations not shown. In embodiments, operations may not include... Figure 3 Each operation is shown. In an embodiment, the operation can be in conjunction with... Figure 3 The different sequences shown are implemented. These and other embodiments are considered to be within the scope of this disclosure. Those skilled in the art will understand that although the various example components are described as performing various functions, other components may perform the functions described in method 300.

[0074] The operation is described below from the perspective of the receiving gNB. From this perspective, the method includes: a first device (e.g., the receiving gNB) receiving a first message from a second device (e.g., the anchor gNB), the first message indicating that the UE is requested to switch to an RRC connected state, for which an SDT process is underway in an RRC inactive state involving the user equipment, the first device, and the second device. The first device generates an RRC establishment message based on the indication that the UE is requested to switch to the RRC connected state and sends the RRC establishment message to the UE in the RRC inactive state.

[0075] The operation is described below from the perspective of the anchor gNB. From this perspective, the method includes: receiving an indication from the user equipment in an RRC message or from a first device (e.g., the receiving gNB) in an XnAP message, the indication indicating that the amount of uplink SDT data exceeds a threshold or that uplink non-SDT data will be transmitted by the user equipment; determining, based on the received message, to switch the user equipment from an RRC inactive state to an RRC connected state; and sending a first message to the first device indicating that the user equipment is requested to switch to the RRC connected state, for which an SDT process is underway in an RRC inactive state involving the user equipment, the first device, and the second device (e.g., the anchor gNB).

[0076] According to an embodiment, the first message (from the anchor gNB to the receiving gNB) includes (or is represented as) an RRC release message. In this case, the receiving gNB may determine to perform at least one of the following operations: terminate the SDT transaction and send the RRC release message to the UE, or switch the UE to RRC connected state and generate an RRC establishment message and send the RRC establishment message to the UE. In the embodiment, the receiving gNB sends the received RRC release message or RRC establishment message based on this determination. For example, the former may be a simpler solution because it may not be necessary to generate an RRC establishment message, while the latter may allow the UE to switch from RRC inactive state to RRC connected state more quickly.

[0077] Now for reference Figure 4This diagram illustrates a block diagram of example components of a UE or (e.g., RAN or core network) network device. The device includes an electronic storage device 410, a processor 420, a network interface 440, and a memory 450. The various components can be communicatively coupled to each other. The processor 420 can be and include any type of processor, such as a single-core central processing unit (CPU), a multi-core CPU, a microprocessor, a digital signal processor (DSP), a system-on-a-chip (SoC), or any other type of processor. The memory 450 can be a volatile type of memory, such as RAM, or a non-volatile type of memory, such as NAND flash memory. The memory 450 includes processor-readable instructions executable by the processor 420 to cause the device to perform various operations, including those mentioned herein, such as... Figure 3 The operation.

[0078] Electronic storage device 410 can be and includes any type of electronic storage device for storing data, such as hard disk drives, solid-state drives, optical discs and / or other non-transitory computer-readable media, as well as other types of electronic storage devices. Electronic storage device 410 stores processor-readable instructions for causing or configuring a device to perform its operations, and also stores data associated with such operations, such as data related to the 5G NR standard and other data. Network interface 440 can implement wireless networking technologies, such as 5G NR and / or other wireless networking technologies.

[0079] Figure 4 The components shown are merely examples, and those skilled in the art will understand that the apparatus includes other components not shown, and may include multiples of any of the components shown. These and other embodiments are considered to be within the scope of this disclosure.

[0080] Other embodiments of this disclosure include the following examples.

[0081] Example 1.1. A first device comprising: A component for receiving a first message from a second device, the first message indicating that a user equipment (UE) has been requested to switch to an RRC connected state, for which a small data transmission (SDT) process is in progress in a radio resource control (RRC) inactive state involving the user equipment, the first device, and the second device; A component for generating an RRC establishment message based on an indication that the UE has been requested to switch to RRC connected state; and A component used to send RRC establishment messages to UEs that are in an RRC inactive state.

[0082] Example 1.2. According to the first device of Example 1.1, the first message is an Xn Application Protocol (XnAP) UE context retrieval response message.

[0083] Example 1.3. According to the first apparatus of Example 1.1, indicating that the UE is requested to switch to the RRC connected state includes at least one of the following: indicating the end of the SDT procedure, indicating that the downlink data size in the buffer exceeds the data size used for SDT transmission, indicating that a non-SDT transmission will be sent, or indicating a request or need to switch to the RRC connected state.

[0084] Example 1.4. A first apparatus according to any one of Examples 1.1 to 1.3, wherein the first message is received based on the following: the amount of uplink SDT data exceeds a threshold, or non-SDT data is to be sent.

[0085] Example 1.5. A first device according to any one of Examples 1.1 to 1.4, wherein the first message is received based on an RRC message from a user equipment to a second device, the RRC message indicating that the amount of uplink SDT data exceeds a threshold or that uplink non-SDT data will be sent.

[0086] Example 1.6. A first apparatus according to any one of Examples 1.4 to 1.5, wherein non-SDT transmission is used for transmission on a radio bearer not configured for SDT transmission.

[0087] Example 1.7. A first apparatus according to any one of Examples 1.3 to 1.6, wherein the first apparatus is configured to generate an RRC establishment message including an indication received from a second apparatus.

[0088] Example 1.8. A first means according to any one of Examples 1.1 to 1.7, wherein the first means is a receiving gNodeB involved in the SDT process.

[0089] Example 1.9. A first device according to any one of Examples 1.1 to 1.8, wherein the second device is the anchor gNodeB involved in the SDT process.

[0090] Example 1.10. According to the first device of Example 1.1, wherein the first device is configured to receive a third message from the UE after sending an RRC establishment message to the UE.

[0091] Example 1.11. According to the first device of Example 1.10, the third message is an RRC establishment complete message.

[0092] Example 1.12. A first apparatus according to Example 1.1, wherein the first apparatus is configured to: receive an RRC release message included in a first message, and determine at least one of the following: terminate the SDT transaction and send the RRC release message to the UE, or switch the UE to the RRC connection state and generate an RRC establishment message and send the RRC establishment message to the UE.

[0093] Example 1.13. According to the first device of Example 1.1, the RRC establishment message causes the UE to move to the RRC connected state.

[0094] Example 2.1. A second device comprising: A component for receiving an indication from a user equipment in an RRC message or from a first device in an XnAP message, the indication being used to indicate that the amount of uplink small data transmission (SDT) data exceeds a threshold or that uplink non-SDT data will be sent by the user equipment. Components for determining, based on received messages, whether to switch a user equipment from an RRC inactive state to an RRC connected state; and A component for sending a first message to a first device, the first message indicating that the user equipment is requested to switch to an RRC connected state, for which an SDT process is in progress in an RRC inactive state involving the user equipment, the first device, and the second device.

[0095] Example 3.1. A first device (e.g., receiving a gNB) includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first device to perform at least the following: A first message is received from the second device, which indicates that the user equipment (UE) is requested to switch to the RRC connected state, for which a small data transmission (SDT) process is in progress in the radio resource control (RRC) inactive state involving the user equipment, the first device and the second device; An RRC establishment message is generated based on the indication that the UE has been requested to switch to RRC connected state; and Send an RRC establishment message to the UE that is in an RRC inactive state.

[0096] Example 4.1. A second device (e.g., an anchor gNB) includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second device to at least: receive an indication from a user equipment in an RRC message or from a first device in an XnAP message, the indication indicating that the amount of uplink small data transfer (SDT) data exceeds a threshold or that uplink non-SDT data will be transmitted by the user equipment; determine, based on the received message, to switch the user equipment from an RRC inactive state to an RRC connected state; and send a first message to the first device indicating that the user equipment is requested to switch to an RRC connected state, for which an SDT process is in progress in an RRC inactive state involving the user equipment, the first device, and the second device.

[0097] The embodiments and aspects disclosed herein are examples of this disclosure and may be embodied in various forms. For example, although some embodiments herein are described as separate embodiments, each embodiment herein may be combined with one or more other embodiments herein. The specific structural and functional details disclosed herein should not be construed as limiting, but rather serve as the basis for the claims and as a representative basis for teaching those skilled in the art to employ this disclosure differently with virtually any suitable detailed structure. Throughout the description of the accompanying drawings, the same reference numerals may refer to similar or identical elements.

[0098] For example, in various embodiments, the anchor gNB involved in the SDT process can be divided into a central unit control plane (gNB-CU CP) and a central unit user plane (gNB-CU UP). The gNB-CU UP can detect that the downlink data size in the buffer exceeds the data size used for SDT transmission and notify the gNB-CU CP that the downlink data size in the buffer exceeds the data size used for SDT transmission. The gNB-CU CP can trigger the transmission of a first message (e.g., Xn retrieves the UE context message) and instruct the UE to switch to RRC connected state.

[0099] In various embodiments, the anchor gNodeB involved in the SDT process is split into gNB-CU CP and gNB-CU UP, which may include gNB-CU UP detecting downlink non-SDT data or downlink data to be transmitted, and notifying gNB-CU CP of downlink non-SDT data or downlink data to be transmitted. gNB-CU CP may trigger the transmission of a first message (e.g., Xn retrieves the UE context message) and instruct the UE to switch to RRC connected state.

[0100] The phrases “in one respect,” “in all respects,” “in all aspects,” “in some respects,” or “in other respects” may each refer to one or more of the same or different respects under this disclosure. The phrase “multiple” may refer to two or more.

[0101] The phrases “in an embodiment,” “in multiple embodiments,” “in various embodiments,” “in some embodiments,” or “in other embodiments” may each refer to one or more of the same or different embodiments according to this disclosure. The phrase “A or B” means “(A), (B), or (A and B).” The phrase “at least one of A, B, or C” means “(A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C).”

[0102] Any method, program, algorithm, or code described herein can be translated into or expressed in a programming language or computer program. As used herein, the terms "programming language" and "computer program" each include any language used to specify instructions to a computer, and include (but are not limited to) the following languages ​​and their derivatives: assembly language, Basic, batch files, BCPL, C, C++, Delphi, Fortran, Java, JavaScript, machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, Visual Basic, meta-languages ​​that specify their own programs, and all first-, second-, third-, fourth-, fifth-, and higher-generation computer languages. Databases and other data schemas, and any other meta-languages, are also included. There is no distinction between languages ​​that are interpreted, compiled, or use compiled and interpreted methods. There is no distinction between compiled and source versions of a program. Therefore, a reference to a program in which a programming language may exist in more than one state (such as source, compiled, object, or linked) is a reference to any and all such states. A reference to a program may encompass the actual instructions and / or the intent of those instructions.

[0103] While various aspects of this disclosure have been shown in the accompanying drawings, they are not intended to be limited thereto, as the scope of this disclosure is intended to be as broad as would be permitted in the art, and the specification is read in the same manner. Therefore, the above description should not be construed as restrictive, but merely as an example of particular aspects. Other modifications within the scope and spirit of the appended claims will be contemplated by those skilled in the art.

Claims

1. A method comprising: The first device receives a first message from the second device, the first message indicating that the user equipment (UE) is requested to switch to the RRC connected state, for which a small data transmission (SDT) process is in progress in the radio resource control (RRC) inactive state involving the user equipment, the first device and the second device; The first device generates an RRC establishment message based on an indication that the UE is requested to switch to the RRC connection state; as well as The first device sends the RRC establishment message to the UE that is in the RRC inactive state.

2. The method according to claim 1, wherein the first message is an Xn Application Protocol (XnAP) UE Context Retrieval Response Message.

3. The method of claim 1, wherein instructing the UE to be requested to switch to the RRC connected state comprises at least one of the following: instructing the end of the SDT process, instructing that the downlink data size in the buffer exceeds the data size for SDT transmission, instructing that non-SDT transmission will be sent, or instructing a request or need to switch to the RRC connected state.

4. The method according to any one of the preceding claims, wherein the first message is received based on the following: the amount of uplink SDT data exceeds a threshold, or non-SDT data is to be sent.

5. The method according to any one of the preceding claims, wherein the first message is received based on an RRC message from the user equipment to the second device, the RRC message indicating that the amount of uplink SDT data exceeds a threshold or that uplink non-SDT data will be sent.

6. The method according to any one of claims 4 to 5, wherein the non-SDT transmission is used for transmission on a radio bearer not configured for SDT transmission.

7. The method according to any one of claims 3 to 6, wherein the first device generates the RRC establishment message including the instruction received from the second device.

8. The method according to any one of the preceding claims, wherein the first device is a receiving gNodeB involved in the SDT process.

9. The method according to any one of the preceding claims, wherein the second device is the anchor gNodeB involved in the SDT process.

10. The method according to claim 1, further comprising: After sending the RRC establishment message to the UE, the first device receives a third message from the UE.

11. The method of claim 10, wherein the third message is an RRC establishment completion message.

12. The method according to claim 1, further comprising: The first device receives the RRC release message included in the first message and determines at least one of the following: terminates the SDT transaction and sends the RRC release message to the UE, or switches the UE to RRC connection state and generates an RRC establishment message and sends the RRC establishment message to the UE.

13. The method according to claim 1, wherein the RRC establishment message causes the UE to move to the RRC connected state.

14. A method comprising: The second device receives an indication from the user equipment in an RRC message or from the first device in an XnAP message, the indication being used to indicate that the amount of uplink small data transmission (SDT) data exceeds a threshold or that uplink non-SDT data will be sent by the user equipment; The second device determines, based on the received message, whether to switch the user equipment from the RRC inactive state to the RRC connected state; as well as The second device sends a first message to the first device, the first message indicating that the user equipment is requested to switch to the RRC connected state, for which an SDT process is in progress in the RRC inactive state involving the user equipment, the first device and the second device.

15. A first device, comprising: At least one processor; as well as At least one memory storing instructions that, when executed by the at least one processor, cause the first device to perform at least the method according to any one of claims 1 to 13.

16. A processor-readable medium storing instructions that, when executed by at least one processor of a first device, cause the first device to perform at least the method according to any one of claims 1 to 13.

17. A second device, comprising: At least one processor; as well as At least one memory storing instructions that, when executed by the at least one processor, cause the second device to perform at least the method according to claim 14.

18. A processor-readable medium storing instructions that, when executed by at least one processor of a second device, cause the second device to perform at least the method according to claim 14.

19. A first device, comprising: Memory; as well as A processor, operatively coupled to and communicating with the memory, is configured to: A first message is received from the second device, indicating that the user equipment (UE) is requested to switch to the RRC connected state, wherein a small data transmission (SDT) process is in progress in the radio resource control (RRC) inactive state involving the user equipment, the first device, and the second device; An RRC establishment message is generated based on an instruction that the UE is requested to switch to the RRC connected state; and the RRC establishment message is sent to the UE that is in the RRC inactive state.

20. A second device, comprising: Memory; as well as A processor, operatively coupled to and communicating with the memory, is configured to: The user equipment receives an indication in an RRC message or in an XnAP message from a first device, the indication indicating that the amount of uplink small data transmission (SDT) data exceeds a threshold or that uplink non-SDT data will be sent by the user equipment; based on the received message, the user equipment is switched from RRC inactive state to RRC connected state. And send a first message to the first device, the first message indicating that the user equipment is requested to switch to the RRC connected state, for which an SDT process is in progress in the RRC inactive state involving the user equipment, the first device and the second device.

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