Terminal device, communication method and base station device

Abstract

To provide a technique related to a terminal device and a communication method which can reduce complexity of protocol processing and efficiently perform communication.SOLUTION: A terminal device according to one embodiment of the present invention receives an RRC re-setting message including DRB setting, performs the first determination for determining that all of conditions that a DRB identifier included in the DRB setting does not exist in the current setting of the terminal device, SDAP setting is included in the DRB setting and an SDAP entity corresponding to a PDU session indicated by a PDU session information element included in the SDAP setting does not exist are satisfied when processing an RRC message, establishes the SDAP entity on the basis of the first determination, and notifies that a user-place resource to the PDU session information element is established in the upper layer on the basis of the second determination for determining that the first determination and the SDAP entity do not exist before receiving the RRC re-setting message.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a terminal device, a communication method, and a base station device. [Background technology]

[0002] A radio access method and radio network for cellular mobile communications (hereinafter referred to as "Long Term Evolution (LTE: registered trademark)" or "Evolved Universal Terrestrial Radio Access: EUTRA"), and a core network (hereinafter referred to as "Evolved Packet Core: EPC") are being considered in the 3rd Generation Partnership Project (3GPP: registered trademark).

[0003] In addition, 3GPP (registered trademark) is currently studying and formulating standards for LTE-Advanced Pro, an extension of LTE, and NR (New Radio technology), a new radio access technology, as radio access methods and radio network technologies for the fifth generation cellular system (Non-Patent Document 1). Also, 5GC (5th Generation Core Network), a core network for the fifth generation cellular system, is being studied (Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP RP-170855, “Work Item on New Radio (NR) Access Technology” [Non-Patent Document 2] 3GPP TS 23.501, “System Architecture for the 5G System; Stage 2” [Non-Patent Document 3] 3GPP TS 36.300, “Evolved Universal Terestrial Radio Access (E-UTRA) and Evolved Universal Terestrial Radio Access Network (E-UTRAN);Overall description; Stage 2”

Non-licensed Document 4

Non-licensed Document 5

Non-licensed Document 6

Non-licensed Document 7

Non-licensed literature 9

[0005] As part of the technical studies for NR, a radio access layer protocol is being considered that will manage QoS (Quality of Service) between the IP (Internet Protocol) layer and higher layers and the NR radio access layer.

[0006] However, if QoS management is not performed correctly between the upper layer and the radio access layer, there is a problem that communication between the base station apparatus and the terminal apparatus cannot be performed efficiently.

[0007] One aspect of the present invention has been made in consideration of the above-mentioned circumstances, and one of its objects is to provide a terminal device, a communication method, and a base station device that can efficiently communicate with a base station device. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, one aspect of the present invention is a terminal device that communicates with a base station device, comprising: a receiving unit that receives an RRC (Radio Resource Control) reconfiguration message including a DRB (Data Radio Bearer) setting from the base station device; and a processing unit, wherein, when processing the RRC reconfiguration message received by the receiving unit, (a) determines that a DRB identifier included in the DRB setting is not present in the current setting of the terminal device, (b) determines that the DRB setting includes an SDAP (Service Data Adaptation Protocol) setting, and (c) determines that an SDAP entity corresponding to a PDU session indicated by a PDU (Protocol Data Unit) session information element included in the SDAP setting does not exist, and if it determines that (a), (b), and (c) are satisfied, establishes an SDAP entity, and further, if the SDAP entity corresponding to the PDU session indicated by the PDU session information element did not exist before receiving the RRC reconfiguration message, notifies a higher layer that user-plane resources for the PDU session information element have been established.

[0009] One aspect of the present invention is a communication method of a terminal device communicating with a base station device, which receives an RRC (Radio Resource Control) reconfiguration message including a DRB (Data Radio Bearer) setting from the base station device, and when processing the received RRC reconfiguration message, (a) determines that a DRB identifier included in the DRB setting does not exist in the current setting of the terminal device, (b) determines that the DRB setting includes an SDAP (Service Data Adaptation Protocol) setting, and (c) determines that an SDAP entity corresponding to a PDU session indicated by a PDU (Protocol Data Unit) session information element included in the SDAP setting does not exist, and if it is determined that (a), (b), and (c) are satisfied, establishes an SDAP entity, and further, if the SDAP entity corresponding to the PDU session indicated by the PDU session information element did not exist before receiving the RRC reconfiguration message, notifies a higher layer that user-plane resources for the PDU session information element have been established.

[0010] According to one aspect of the present invention, a base station device that communicates with a terminal device includes a transmitter that transmits an RRC (Radio Resource Control) reconfiguration message including a DRB (Data Radio Bearer) setting to the terminal device, and a processor that causes the terminal device to perform processing by including the DRB setting in the RRC reconfiguration message, the processor including, when processing the RRC reconfiguration message received by the terminal device, (a) determining that a DRB identifier included in the DRB setting does not exist in a current setting of the terminal device, (b) determining that a Service Data Adaptation Protocol (SDAP) setting is included in the DRB setting, and (c) determining that a Protocol Data Unit (PDU) included in the SDAP setting is included in the DRB setting. a SDAP entity corresponding to the PDU session indicated by the PDU session information element does not exist, and if it is determined that (a), (b), and (c) are satisfied, establishes an SDAP entity; and if the SDAP entity corresponding to the PDU session indicated by the PDU session information element did not exist before receiving the RRC reconfiguration message, notifies a higher layer that user-plane resources for the PDU session information element have been established.

[0011] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. Effect of the Invention

[0012] According to one aspect of the present invention, a terminal device can reduce the complexity of protocol processing and perform communication efficiently. [Brief description of the drawings]

[0013] [Figure 1]1 is a schematic diagram of a communication system according to each embodiment of the present invention. [Diagram 2] FIG. 2 is a protocol stack diagram of the UP and CP of a terminal device and a base station device in E-UTRA in each embodiment of the present invention. [Diagram 3] A protocol stack diagram of UP and CP of a terminal device and a base station device in NR in each embodiment of the present invention. [Figure 4] FIG. 2 is a diagram showing an example of a flow of an RRC reconfiguration procedure in each embodiment of the present invention. [Diagram 5] FIG. 2 is a block diagram showing a configuration of a terminal device in each embodiment of the present invention. [Figure 6] FIG. 2 is a block diagram showing a configuration of a base station device in each embodiment of the present invention. [Figure 7] 1A to 1C are diagrams showing examples of information relating to radio bearer setting and ASN.1 (Abstract Syntax Notation One) description of the information in each embodiment of the present invention. [Figure 8] 3 shows an example of a processing method according to an embodiment of the present invention. [Figure 9] 6 shows another example of a processing method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0015] LTE (and LTE-A Pro) and NR may be defined as different RATs. NR may be defined as a technology included in LTE. LTE may be defined as a technology included in NR. LTE, which is connectable to NR by Multi RAT Dual connectivity (MR-DC) as described in Non-Patent Document 7, may be distinguished from conventional LTE. This embodiment may be applied to NR, LTE, and other RATs. In the following description, terms related to LTE and NR are used, but the present embodiment may be applied to other technologies using other terms. The term E-UTRA in this embodiment may be replaced with the term LTE, and the term LTE may be replaced with the term E-UTRA.

[0016] FIG. 1 is a schematic diagram of a communication system according to each embodiment of the present invention.

[0017] E-UTRA 100 is a radio access technology described in Non-Patent Document 3 and the like, and is composed of cell groups (CGs) consisting of one or more frequency bands. eNB (E-UTRAN Node B) 102 is a base station device of E-UTRA. EPC (Evolved Packet Core) 104 is a core network described in Non-Patent Document 14 and the like, and was designed as a core network for E-UTRA. Interface 112 is an interface between eNB 102 and EPC 104, and includes a control plane (CP) through which control signals pass, and a user plane (UP) through which user data passes.

[0018] NR 106 is a radio access technology described in Non-Patent Document 9 and the like, and is composed of cell groups (CGs) consisting of one or more frequency bands. gNB (g Node B) 108 is a base station device for NR. 5GC 110 is a core network described in Non-Patent Document 2 and the like, and is designed as a core network for NR, but may also be used as an E-UTRA core network with a function of connecting to 5CG. Hereinafter, E-UTRA may include E-UTRA with a function of connecting to 5CG.

[0019] The interface 114 is an interface between the eNB 102 and the 5GC 110, the interface 116 is an interface between the gNB 108 and the 5GC 110, the interface 118 is an interface between the gNB 108 and the EPC 104, the interface 120 is an interface between the eNB 102 and the gNB 108, and the interface 124 is an interface between the EPC 104 and the 5GC 110. The interfaces 114, 116, 118, 120, and 124 are interfaces that pass only a CP, only a UP, or both a CP and an UP. Also, the interfaces 114, 116, 118, 120, and 124 may not exist depending on the communication system provided by the communication carrier.

[0020] The UE 122 is a terminal device that supports NR or supports both E-UTRA and NR.

[0021] FIG. 2 is a diagram showing protocol stacks of UP and CP of a terminal device and a base station device in an E-UTRA radio access layer in each embodiment of the present invention.

[0022] FIG. 2A is a protocol stack diagram of the UP used when the UE 122 communicates with the eNB 102 in the E-UTRA 100.

[0023] The PHY (Physical layer) 200 is a wireless physical layer, and provides a transmission service to an upper layer by using a physical channel. The PHY 200 is connected to a higher-level MAC (Medium Access Control layer) 202 (described later) by a transport channel. Data moves between the MAC 202 and the PHY 200 via the transport channel. Data is transmitted and received between the PHYs of the UE 122 and the eNB 102 via a wireless physical channel.

[0024] The MAC 202 is a medium access control layer that maps various logical channels to various transport channels. The MAC 202 is connected to a higher-level RLC (Radio Link Control layer) 204 (described later) via a logical channel. The logical channels are broadly classified according to the type of information to be transmitted, and are divided into control channels that transmit control information and traffic channels that transmit user information. The MAC 202 has functions such as controlling the PHY 200 to perform discontinuous transmission and reception (DRX / DTX), executing a random access procedure, notifying information on transmission power, and performing HARQ control (Non-Patent Document 7).

[0025] The RLC 204 is a radio link control layer that segments data received from the higher-level PDCP (Packet Data Convergence Protocol Layer) 206 (described later) and adjusts the data size so that the lower layer can transmit the data appropriately. The RLC 200 also has a function to guarantee the Quality of Service (QoS) required by each data. In other words, the RLC 204 has a function such as data retransmission control (Non-Patent Document 6).

[0026] The PDCP 206 is a packet data convergence protocol layer for efficiently transmitting IP packets, which are user data, over wireless sections. The PDCP 206 may have a header compression function for compressing unnecessary control information. The PDCP 206 may also have a data encryption function (see Non-Patent Document 5).

[0027] The data processed in the MAC 202, RLC 204, and PDCP 206 are called MAC PDU (Protocol Data Unit), RLC PDU, and PDCP PDU, respectively. Moreover, the data passed to the MAC 202, RLC 204, and PDCP 206 from a higher layer or passed to a higher layer are called MAC SDU (Service Data Unit), RLC SDU, and PDCP SDU, respectively.

[0028] FIG. 2B is a protocol stack diagram of the CP used when the UE 122 communicates with the eNB 102 in the E-UTRA 100.

[0029] The protocol stack of the CP includes a PHY 200, a MAC 202, an RLC 204, a PDCP 206, and an RRC (Radio Resource Control layer) 208. The RRC 208 is a radio link control layer that performs setting and re-setting of radio bearers (RBs) and controls logical channels, transport channels, and physical channels. The RBs may be divided into signaling radio bearers (SRBs) and data radio bearers (DRBs), and the SRBs may be used as a path for transmitting RRC messages, which are control information. The DRBs may be used as a path for transmitting user data. Setting of each RB may be performed between the eNB 102 and the RRC 208 of the UE 122 (Non-Patent Document 4).

[0030] The above-mentioned functional classification of the MAC 202, the RLC 204, the PDCP 206, and the RRC 208 is an example, and some or all of the functions may not be implemented. Also, some or all of the functions of each layer may be included in another layer.

[0031] The IP layer, and layers above the IP layer such as the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and application layer are upper layers of the PDCP layer (not shown). The RRC layer and the NAS (non-access strarum) layer are also upper layers of the SDAP layer (not shown). In other words, the PDCP layer is a lower layer than the RRC layer, the NAS layer, the IP layer, and layers above the IP layer such as the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and application layer.

[0032] FIG. 3 is a protocol stack diagram of the UP and CP of a terminal device and a base station device in the NR radio access layer in each embodiment of the present invention.

[0033] FIG. 3(A) is a protocol stack diagram of the UP used when a UE 122 communicates with a gNB 108 in an NR 106.

[0034] The PHY (Physical layer) 300 is a radio physical layer of NR and may provide a transmission service to a higher layer using a physical channel. The PHY 300 may be connected to a higher MAC (Medium Access Control layer) 302 (described later) via a transport channel. Data may be transferred between the MAC 302 and the PHY 300 via the transport channel. Data may be transmitted and received between the PHYs of the UE 122 and the gNB 108 via a radio physical channel.

[0035] The MAC 302 is a medium access control layer that maps various logical channels to various transport channels. The MAC 302 may be connected to a higher-level RLC (Radio Link Control layer) 304 (described later) via a logical channel. The logical channels are broadly classified according to the type of information to be transmitted, and may be classified into a control channel that transmits control information and a traffic channel that transmits user information. The MAC 302 may have a function to control the PHY 300 in order to perform discontinuous transmission and reception (DRX / DTX), a function to execute a random access procedure, a function to notify information on transmission power, a function to perform HARQ control, and the like (Non-Patent Document 13).

[0036] The RLC 304 is a radio link control layer that segments data received from the higher-level PDCP (Packet Data Convergence Protocol Layer) 206 (described later) and adjusts the data size so that the lower layers can transmit the data appropriately. The RLC 304 may also have a function for guaranteeing the Quality of Service (QoS) required by each piece of data. In other words, the RLC 304 may have a function for controlling retransmission of data, etc. (Non-Patent Document 12).

[0037] The PDCP 306 is a packet data convergence protocol layer that efficiently transmits IP packets, which are user data, over wireless sections. The PDCP 306 may have a header compression function that compresses unnecessary control information. The PDCP 306 may also have a data encryption function (Non-Patent Document 11).

[0038] The SDAP (Service Data Adaptation Protocol) 310 is a service data adaptation protocol layer that has a function of mapping the downlink QoS flow sent from the core network to the terminal device via the base station device with the DRB, and mapping the uplink QoS flow sent from the terminal device to the core network via the base station device with the DRB, and storing mapping rule information (Non-Patent Document 16). When the terminal device receives the SDAP SDU together with the QoS flow information from the upper layer, the SDAP SDU is assigned to the corresponding DRB based on the stored mapping rule between the QoS flow and the DRB. If the mapping rule between the QoS flow and the DRB is not stored, the SDAP SDU may be assigned to a default radio bearer (default DRB). The QoS flow consists of one or more service data flows (SDFs) that are processed by the same QoS policy (Non-Patent Document 2). The SDAP may also have a function of reflective QoS that maps the uplink QoS flow to the DRB based on the information of the downlink QoS flow. In addition, if the correspondence rules between QoS flows and DRBs are changed, an End Marker DPU can be created and sent to the previous DRB to ensure in-sequence delivery of SDAP SDUs (Non-Patent Document 2, Non-Patent Document 16).

[0039] The end marker PDU is an SDAP control PDU described in non-patent document 16, which is used by the SDAP entity of the UE to notify that the mapping between the QoS flow corresponding to the QoS flow identifier contained in the QoS flow identifier field of this end marker PDU and the radio bearer through which this end marker PDU was transmitted has ended.

[0040] The IP layer, and layers above the IP layer such as the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and application layer are upper layers of the SDAP layer (not shown). The RRC layer and the NAS (non-access strarum) layer are also upper layers of the SDAP layer (not shown). The NAS layer associates service data flows with QoS flows. In other words, the SDAP layer is a lower layer than the RRC layer, the NAS layer, the IP layer, and layers above the IP layer such as the TCP (Transmission Control Protocol) layer, UDP (User Datagram Protocol) layer, and application layer.

[0041] The data processed in the MAC 302, the RLC 304, the PDCP 306, and the SDAP 310 may be called a MAC PDU (Protocol Data Unit), an RLC PDU, a PDCP PDU, and an SDAP PDU, respectively. Moreover, the data passed to the MAC 202, the RLC 204, and the PDCP 206 from a higher layer or passed to a higher layer may be called a MAC SDU (Service Data Unit), an RLC SDU, a PDCP SDU, and an SDAP SDU, respectively.

[0042] Figure 3(B) is a protocol stack diagram of the CP used when UE 122 communicates with gNB 108 in NR 106.

[0043] The protocol stack of the CP includes PHY 300, MAC 302, RLC 304, PDCP 306, and RRC (Radio Resource Control layer) 308. RRC 308 is a radio link control layer that performs setting and re-setting of radio bearers (RBs) and controls logical channels, transport channels, and physical channels. RBs may be divided into signaling radio bearers (SRBs) and data radio bearers (DRBs), and SRBs may be used as paths for transmitting RRC messages, which are control information. DRBs may be used as paths for transmitting user data. Setting of each RB may be performed between gNB 108 and RRC 308 of UE 122. A part of the RBs that is composed of RLC 304 and MAC 302 may be called an RLC bearer (Non-Patent Document 10).

[0044] The above-mentioned functional classification of MAC 302, RLC 304, PDCP 306, SDAP 310, and RRC 308 is an example, and some or all of the functions may not be implemented. Also, some or all of the functions of each layer may be included in another layer.

[0045] In each embodiment of the present invention, in order to distinguish between the E-UTRA protocol and the NR protocol, the MAC 202, the RLC 204, the PDCP 206, and the RRC 208 may be referred to as the MAC for E-UTRA or the MAC for LTE, the RLC for E-UTRA or the RLC for LTE, the PDCP for E-UTRA or the PDCP for LTE, and the RRC for E-UTRA or the RRC for LTE, respectively. The MAC 302, the RLC 304, the PDCP 306, and the RRC 308 may be referred to as the MAC for NR, the RLC for NR, the RLC for NR, and the RRC for NR, respectively. Alternatively, they may be written with spaces, such as E-UTRA PDCP or LTE PDCP, NR PDCP, etc.

[0046] Also, as shown in FIG. 1, the eNB 102, the gNB 108, the EPC 104, and the 5GC 110 may be connected via an interface 112, an interface 116, an interface 118, an interface 120, and an interface 114. Therefore, in order to support various communication systems, the RRC 208 in FIG. 2 may be replaced with the RRC 308 in FIG. 3. The PDCP 206 in FIG. 2 may be replaced with the PDCP 306 in FIG. 3. The RRC 308 in FIG. 3 may include the function of the RRC 208 in FIG. 2. The PDCP 306 in FIG. 3 may be the PDCP 206 in FIG. 2. In the E-UTRA 100, even when the UE 122 communicates with the eNB 102, the NR PDCP may be used as the PDCP.

[0047] (Embodiment) An embodiment of the present invention will be described with reference to Figures 1 to 9. In the embodiment of the present invention, when an SDAP entity is established, the fact that user plane resources for a PDU session have been established or configured is notified to upper layers when a new PDU session is established.

[0048] 4 is a diagram showing an example of a flow of an RRC reconfiguration procedure in each embodiment of the present invention. Note that the RRC reconfiguration procedure may be an RRC connection reconfiguration procedure.

[0049] The RRC connection reconfiguration procedure is a procedure used for the establishment, change, release, and secondary cell change and release of a radio bearer (RB) in LTE, as described in Non-Patent Document 4, as well as for the setting of handover and measurement. On the other hand, the RRC reconfiguration procedure is a procedure used for the establishment, change, release, and secondary cell change and release of an RB in NR, as described in Non-Patent Document 10, as well as for the setting of handover (reconfiguration involving synchronization) and measurement. In the embodiment of the present invention, information included in each message in the RRC connection reconfiguration procedure for setting the above-mentioned RB establishment, change, release, secondary cell change, release, handover, measurement, etc. is called setting information. In addition, the setting information is not limited to the above-mentioned setting, and may be other setting, and may be included in each message in another procedure, not limited to the RRC connection reconfiguration procedure.

[0050] The RRC connection reconfiguration procedure may also be used in MR-DC (Multi-RAT Dual Connectivity) described in Non-Patent Document 8, particularly in EN-DC (E-UTRA-NR Dual Connectivity) (options 3 and 3a described in Non-Patent Document 17), which is MR-DC when the core network is EPC104 and the master node is eNB102 (also referred to as enhanced eNB102), NGEN-DC (NG-RAN E-UTRA-NR Dual Connectivity) (options 7 and 7a described in Non-Patent Document 17), which is MR-DC when the core network is 5GC110 and the master node is eNB102, and E-UTRA / 5GC (option 5 described in Non-Patent Document 17), in which eNB102 (enhanced eNB) uses 5GC as the core network. In this case, the RRC connection reconfiguration procedure may include not only LTE (E-UTRA) configuration information but also NR configuration information described in Non-Patent Document 10. In this case, the RRC connection reconfiguration message may be transmitted from eNB 102 to UE 122 via gNB 108.

[0051] The RRC reconfiguration procedure may also be used in NE-DC (NR-E-UTRA Dual Connectivity) (option 4 and option 4a described in non-patent document 17), which is an MR-DC in which the core network is 5GC 110 and the master node is gNB 108, and in this case, the RRC reconfiguration procedure may include not only NR configuration information but also LTE (E-UTRA) configuration information described in non-patent document 10. In this case, the RRC reconfiguration message may also be transmitted from gNB 108 to UE 122 via eNB 102.

[0052] In each embodiment of the present invention, in order to avoid complicating the explanation, the explanation will be given using the name of the RRC reconfiguration procedure, and the explanation will be given using the gNB 108 as the base station device. Note that the names of architectures such as EN-DC, NGEN-DC, E-UTRA / 5GC, and NE-DC may be other names instead of the above.

[0053] In the RRC reconfiguration procedure, the UE 122 receives an RRC reconfiguration message (RRCReconfiguration) from the gNB 108 (step S400), and performs various settings, such as setting a radio bearer and setting an SDAP, in accordance with information included in the RRC reconfiguration message (step S402). After step S402, the UE 122 may send an RRC reconfiguration complete message (RRCReconfigurationComplete) to the gNB 108 (not shown). Note that the RRC reconfiguration message may be rephrased as RRC reconfiguration, and the RRC reconfiguration complete message may be rephrased as RRC reconfiguration completion.

[0054] Fig. 5 is a block diagram showing the configuration of a terminal device (UE 122) in each embodiment of the present invention. In order to avoid complicating the explanation, Fig. 5 shows only main components closely related to the present invention.

[0055] The UE 122 shown in Figure 5 comprises a receiver 500 that receives an RRC reconfiguration message, etc. from the gNB 108, and a processor 502 that performs processing according to configuration information, such as various information elements (IEs) and / or various fields and / or various conditions, contained in the received message.

[0056] Fig. 6 is a block diagram showing the configuration of a base station device (gNB 108) in each embodiment of the present invention. In order to avoid complicating the explanation, Fig. 6 shows only main components closely related to the present invention.

[0057] The gNB 108 shown in Fig. 6 includes a transmitter 600 that transmits an RRC reconfiguration message or the like to the UE 122, and a processor 602 that creates an RRC reconfiguration message including configuration information such as various information elements (IEs), various fields, and / or various conditions, and transmits the message to the UE 122, thereby causing the processor 502 of the UE 122 to perform processing. Note that the configuration shown in Fig. 6 may be applied to the eNB 102. When applied to the eNB 102, the message transmitted from the transmitter 600 to the UE 122 may be an RRC connection reconfiguration message.

[0058] FIG. 7 is an example of an ASN.1 (Abstract Syntax Notation One) description representing information elements included in the RRC reconfiguration message in FIG. 4 in the first embodiment of the present invention. In 3GPP (registered trademark), specifications related to RRC (Non-Patent Document 4, Non-Patent Document 10) describe messages and information elements (Information Elements: IEs) related to RRC using ASN.1. In the example of ASN.1 in FIG. 7, <Omitted> and <Omitted> are not part of the notation of ASN.1, and indicate that other information is omitted. Note that information elements may be omitted even in places where <Omitted> or <Omitted> is not written. Note that the example of ASN.1 in FIG. 7 does not exactly follow the ASN.1 notation method, but describes an example of parameters of RRC reconfiguration in the present invention, and other names and other notations may be used. In addition, the example of ASN.1 in FIG. 7 shows only an example of main information closely related to the present invention in order to avoid complicated explanation.

[0059] In Figure 7, the information element represented by DRB-ToAddModList or DRBToAddMod may be a list of information indicating the setting of a DRB (data radio bearer) to be added or changed, and in an embodiment of the present invention, it may be referred to as a radio bearer setting information element or a data radio bearer information element.

[0060] Among the radio bearer configuration information elements, an information element represented by DRB-Identity is information on the DRB identifier of the DRB to be added or changed, and in the embodiment of the present invention, it may be referred to as a radio bearer identifier information element or a data radio bearer identifier information element. In the example of Fig. 7, it is an integer value from 1 to 32, but it may take another value. In the case of DC, the DRB identifier is unique within the scope of the UE 122.

[0061] The information element represented by cnAssociation in the radio bearer configuration information element may be an information element indicating whether to use EPC 104 or 5GC 110 as the core network, and may be referred to as a core network association information element in the embodiment of the present invention. That is, when UE 122 connects to EPC, the DRB may be associated with the EPS bearer identifier information element (eps-BearerIdentity) in cnAssociation or the EPS bearer identifier that is the value of the EPS bearer identifier information element, and when UE 122 connects to 5GC 110, the DRB may be associated with an SDAP entity that is configured according to a later-described SDAP configuration information element (sdap-Config), or a later-described PDU session information element included in the SDAP configuration information element, or a PDU session identifier that is the value of the PDU session information element, or a PDU session indicated by the PDU session information element. In other words, the information represented by cnAssociation may include an EPS bearer identifier information element (eps-BearerIdentity) when EPC104 is used in the core network, such as when EN-DC is used, and may also include an information element (sdap-Config) indicating SDAP settings when core network 5GC110 is used, i.e., when EN-DC is not used.

[0062] The information element represented by sdap-Config may be information regarding the configuration or reconfiguration of an SDAP entity that determines how QoS flows and DRBs are mapped when the core network is 5GC110, and in embodiments of the present invention, it may be referred to as an SDAP configuration information element.

[0063] The field or information element indicated by pdu-session or PDU-SessionID included in the SDAP configuration information element may be the identifier of the PDU session described in Non-Patent Document 2 to which the QoS flow that is associated (mapped) with the radio bearer corresponding to the value of the radio bearer identifier information element included in the radio bearer configuration information element including this SDAP configuration information element belongs, and may be referred to as the PDU session information element in the embodiments of the present invention. The value of the PDU session information element may be a non-negative integer.

[0064] The information element indicated by mappedQoS-FlowsToAdd included in the SDAP configuration information element may be information indicating a list of QoS flow identity (QFI) information elements (to be described later) of the QoS flows to be mapped to the radio bearer corresponding to the value of the radio bearer identifier information element included in the radio bearer configuration information element including this SDAP configuration information element, or to be additionally mapped, and may be referred to as an additional QoS flow information element in the embodiment of the present invention. The above-mentioned QoS flow may be the QoS flow of the PDU session indicated by the PDU session information element included in this SDAP configuration information element.

[0065] Furthermore, the information element indicated by mappedQoS-FlowsToRelease included in the SDAP configuration information element may be information indicating a list of QoS flow identity (QFI) information elements (to be described later) of the QoS flows to be released from among the QoS flows that correspond (map) to the radio bearer corresponding to the value of the radio bearer identifier information element included in the radio bearer configuration information element including this SDAP configuration information element, and may be rephrased as the QoS flow information element to be released in the embodiment of the present invention. The above-mentioned QoS flow may be the QoS flow of the PDU session indicated by the PDU session information element included in this SDAP configuration information element.

[0066] The information element indicated by QFI may be a QoS flow identifier that uniquely identifies a QoS flow, as described in Non-Patent Document 2, and may be referred to as a QoS flow identifier information element in the embodiments of the present invention. The value of the QoS flow identifier information element may be a non-negative integer. The value of the QoS flow identifier information element may also be unique to a PDU session.

[0067] In addition, the SDAP setting information element may also include an uplink header information element indicating whether or not an uplink SDAP header is present in the uplink data transmitted via the set DRB, a downlink header information element indicating whether or not a downlink SDAP header is present in the downlink data received via the set DRB, and a default bearer information element indicating whether or not the set DRB is a default radio bearer (default DRB).

[0068] Furthermore, the information element represented by pdcp-Config or PDCP-Config in the radio bearer configuration information element may be information related to the configuration of the NR PDCP entity for establishing or changing the PDCP 306 for the SRB or DRB, and may be referred to as a PDCP configuration information element in the embodiment of the present invention. The information related to the configuration of the NR PDCP entity may include information indicating the size of the uplink sequence number, information indicating the size of the downlink sequence number, information indicating the profile of the header compression (RoHC: RObust Header Compression), re-ordering timer information, and the like.

[0069] In addition, the information element represented by DRB-ToReleaseList in the radio bearer setting information element may be list information of the DRB identifiers of the DRBs to be released, and in an embodiment of the present invention, it may be rephrased as the radio bearer information element to be released or the data radio bearer information element to be released.

[0070] Also, some or all of the information elements shown in Fig. 7 may be optional, i.e., the information elements shown in Fig. 7 may be included in the RRC reconfiguration message according to necessity or conditions.

[0071] An example of a processing method of the UE 122 in the embodiment of the present invention will be described with reference to FIG.

[0072] The processing unit 602 of the gNB 108 creates an RRC reconfiguration message including a radio bearer configuration information element for causing the UE 122 to perform processing, and transmits the message to the UE 122 from the transmission unit 600 (not shown). The reception unit 500 of the UE 122 receives the RRC reconfiguration message from the gNB 108 (step S800). The UE 122 may receive an RRC message including the above-mentioned radio bearer configuration information element from the eNB 102.

[0073] Next, the processing unit 502 of the UE 122 determines whether or not the value of the radio bearer identifier information element included in the above-mentioned radio bearer setting information element is set in the UE 122 and whether or not the above-mentioned radio bearer setting information element includes an SDAP setting information element, and performs processing of step S804 described below based on the fact that the value of the radio bearer identifier information element included in the above-mentioned radio bearer setting information element is not set in the UE 122 and / or the fact that the above-mentioned radio bearer setting information element includes an SDAP setting information element (step S802).

[0074] The processing unit 502 of UE 122 determines whether or not an SDAP entity corresponding to the PDU session indicated by the PDU session information element included in the above-mentioned SDAP setting information element exists, and performs processing of step S806 and / or step S808 based on the fact that an SDAP entity corresponding to the PDU session indicated by the PDU session information element included in the above-mentioned SDAP setting information element does not exist (step S804).

[0075] The processing unit 502 of the UE 122 establishes an SDAP entity (step S806). Note that before establishing the above-mentioned SDAP entity, a DRB corresponding to the value of the above-mentioned radio bearer identifier information element may be established by establishing a PDCP entity or the like. Note that after establishing the above-mentioned SDAP entity, the SDAP entity may be further configured or reconfigured. Furthermore, when the SDAP entity is configured or reconfigured, the above-mentioned established DRB may be associated with the above-mentioned SDAP entity.

[0076] The processing unit 502 of the UE 122 determines whether or not an SDAP entity corresponding to the above-mentioned PDU session existed before receiving the above-mentioned RRC reconfiguration message, and notifies the upper layer that "user-plane resources for the above-mentioned PDU session have been established" based on the fact that an SDAP entity corresponding to the above-mentioned PDU session did not exist before receiving the above-mentioned RRC reconfiguration message (step S808). Note that "user-plane resources for the above-mentioned PDU session have been established" may be expressed in other ways, such as "user-plane resources for the above-mentioned PDU session have been set."

[0077] "User plane resources for the above-mentioned PDU session have been established" can also be rephrased as "the QoS flow identifier information element included in the QoS flow information element to be added included in the above-mentioned SDAP configuration information element, or the correspondence rule between the QoS flow and the radio bearer corresponding to the value of the QoS flow identifier information element, has been stored."

[0078] The notification of "the establishment of user plane resources for the above-mentioned PDU session" may be, for example, notification of the above-mentioned PDU session identifier information element or the value of the PDU session identifier information element to the upper layer. In this case, the above-mentioned QoS flow identifier information element or the value of the QoS flow identifier information element may be notified to the upper layer at the same time, or instead of notifying the above-mentioned PDU session identifier information element or the value of the above-mentioned PDU session identifier information element to the upper layer, the value of the above-mentioned QoS flow identifier information element or the QoS identifier information element may be notified to the upper layer.

[0079] Also, "determine whether or not an SDAP entity corresponding to the above-mentioned PDU session existed before receiving the above-mentioned RRC reconfiguration message" may be rephrased or supplemented as "determine whether or not the establishment of the above-mentioned SDAP entity (in step S806) is the result of full configuration." Also, "based on the fact that an SDAP entity corresponding to the above-mentioned PDU session did not exist before receiving the above-mentioned RRC reconfiguration message" may be rephrased or supplemented as "based on the fact that the establishment of the above-mentioned SDAP entity (in step S806) is not the result of full configuration."

[0080] In step S808, "before receiving the RRC reconfiguration message, an SDAP entity corresponding to the PDU session did not exist" may be rephrased as another condition (else) of "before receiving the RRC reconfiguration message, an SDAP entity corresponding to the PDU session existed". In addition, "the establishment of the SDAP entity (in step S806) is not the result of full configuration" may be rephrased as another condition (else) of "the establishment of the SDAP entity (in step S806) is the result of full configuration".

[0081] Next, another example of the processing method of the UE 122 in the embodiment of the present invention will be described with reference to FIG.

[0082] The processing unit 602 of the gNB 108 creates an RRC reconfiguration message including a radio bearer configuration information element for causing the UE 122 to perform processing, and transmits the message to the UE 122 from the transmission unit 600 (not shown). The reception unit 500 of the UE 122 receives the RRC reconfiguration message from the gNB 108 (step S900). The UE 122 may receive an RRC message including the above-mentioned radio bearer configuration information element from the eNB 102.

[0083] Next, the processing unit 502 of the UE 122 determines whether or not the value of the radio bearer identifier information element included in the above-mentioned radio bearer setting information element is set in the UE 122 and whether or not the above-mentioned radio bearer setting information element includes an SDAP setting information element, and performs processing of step S904 described below based on the fact that the value of the radio bearer identifier information element included in the above-mentioned radio bearer setting information element is not set in the UE 122 and / or the fact that the above-mentioned radio bearer setting information element includes an SDAP setting information element (step S902).

[0084] The processing unit 502 of the UE 122 determines whether or not an SDAP entity corresponding to the PDU session indicated by the PDU session information element included in the above-mentioned SDAP setting information element exists, and performs processing of step S906 (to be described later) and / or step S908 (to be described later) based on the fact that an SDAP entity corresponding to the PDU session indicated by the PDU session information element included in the above-mentioned SDAP setting information element does not exist (step S904).

[0085] The processing unit 502 of the UE 122 establishes an SDAP entity (step S806). Note that before establishing the above-mentioned SDAP entity, a DRB corresponding to the value of the above-mentioned radio bearer identifier information element may be established by establishing a PDCP entity or the like. Note that after establishing the above-mentioned SDAP entity, the SDAP entity may be further configured or reconfigured. Furthermore, when the SDAP entity is configured or reconfigured, the above-mentioned established DRB may be associated with the above-mentioned SDAP entity.

[0086] The processing unit 502 of the UE 122 determines whether or not an SDAP entity corresponding to the above-mentioned PDU session existed before receiving the above-mentioned RRC reconfiguration message, and associates the above-mentioned SDAP entity established (in step S906) with the above-mentioned PDU session based on the fact that an SDAP entity corresponding to the above-mentioned PDU session existed before receiving the above-mentioned RRC reconfiguration message (step S908).

[0087] Also, "determine whether or not an SDAP entity corresponding to the above-mentioned PDU session existed before receiving the above-mentioned RRC reconfiguration message" may be rephrased or supplemented as "determine whether or not the establishment of the above-mentioned SDAP entity (in step S906) is the result of full configuration." Also, "based on the fact that an SDAP entity corresponding to the above-mentioned PDU session existed before receiving the above-mentioned RRC reconfiguration message" may be rephrased or supplemented as "based on the fact that the establishment of the above-mentioned SDAP entity (in step S906) is the result of full configuration."

[0088] In step S908, "before receiving the RRC reconfiguration message, an SDAP entity corresponding to the PDU session existed" may be rephrased as another condition (else) of "before receiving the RRC reconfiguration message, an SDAP entity corresponding to the PDU session did not exist". In addition, "the establishment of the SDAP entity (in step S906) is the result of full configuration" may be rephrased as another condition (else) of "the establishment of the SDAP entity (in step S806) is not the result of full configuration".

[0089] In the embodiment of the present invention, the process of notifying the upper layer that "user-plane resources for the PDU session corresponding to the above-mentioned PDU session information element have been established or configured" may be performed by RRC308 or RRC208, or may be performed by SDAP310. The upper layer that notifies "that user-plane resources for the PDU session corresponding to the above-mentioned PDU session information element have been established or configured" may be the NAS layer. The notification of "that user-plane resources for the PDU session corresponding to the above-mentioned PDU session information element have been established or configured" to the upper layer may be performed after RRC308 or RRC208 confirms that the QoS flow identifier information element included in the QoS flow information element to be added, or the QoS flow corresponding to the value of the QoS flow identifier information element, included in the above-mentioned radio bearer configuration information element, has been stored, and the notification may be performed. A method of confirming that the above-mentioned association rule has been stored may be a notification from the SDAP 310 to the RRC 308 or the RRC 208 indicating that the association rule has been stored.

[0090] In this manner, in the embodiment of the present invention, when an SDAP entity is established, the fact that user plane resources for a PDU session have been established or configured is notified to a higher layer when a new PDU session is established, so that the higher layer can detect that user plane resources for a PDU session have been established in a lower layer, and can transmit user data at optimal timing. In other words, the terminal device can reduce the complexity of protocol processing and perform communication efficiently.

[0091] In addition, the radio bearer setup in each embodiment of the present invention may be included not only in the RRC connection re-establishment procedure but also in the RRC establishment procedure or the RRC re-establishment procedure. Also, the radio bearer in each embodiment of the present invention may be a DRB or an SRB.

[0092] In addition, the "information element" in each embodiment of the present invention may be called a "field."

[0093] Furthermore, in each embodiment of the present invention, the notification to the upper layer that "user plane resources for the PDU session corresponding to the PDU session information element have been established" and / or "user-plane resources for the PDU session corresponding to the PDU session information element have been established or configured" may be other information other than the rephrased examples in each embodiment of the present invention, as long as it indicates that "user plane resources for the PDU session corresponding to the PDU session information element have been established" and / or "user-plane resources for the PDU session corresponding to the PDU session information element have been established or configured."

[0094] In addition, in each embodiment of the present invention, "the radio bearer establishment information element includes an SDAP establishment information element" may mean that EN-DC is not used, that is, the opposite of using EN-DC, because, as explained in Non-Patent Document 8 and Non-Patent Document 9, in NR (New Radio technology), EPC is used as a core network only in the case of EN-DC.

[0095] Moreover, the processes and methods of the terminal device and base station device described in each embodiment of the present invention can be summarized, for example, as follows.

[0096] That is, the terminal device communicates with a base station device, and includes a receiving unit that receives an RRC reconfiguration message including a radio bearer configuration information element from the base station device, and a processing unit that, if an SDAP entity for a PDU session information element included in the SDAP configuration information element does not exist based on the fact that a value of a radio bearer identifier information element included in the radio bearer configuration information element does not exist in the configuration of the terminal device and that an SDAP configuration information element is included in the radio bearer configuration information element, establishes an SDAP entity, and further determines whether an SDAP entity for the PDU session information element existed before receiving the RRC reconfiguration message, and, based on the fact that an SDAP entity for the PDU session information element did not exist before receiving the RRC reconfiguration message, notifies a higher layer that user plane resources for a PDU session corresponding to the value of the PDU session information element have been configured, and, based on the fact that an SDAP entity for the PDU session information element existed before receiving the RRC reconfiguration message, associates the established SDAP entity with the PDU session.

[0097] Also, a base station device that communicates with a terminal device has a transmitting unit that transmits an RRC reconfiguration message including a radio bearer configuration information element to the terminal device, and a processing unit that includes a radio bearer configuration information element in the RRC reconfiguration message and causes the terminal device to perform processing, wherein the processing is a processing of establishing an SDAP entity if an SDAP entity for a PDU session information element included in the SDAP configuration information element does not exist based on the fact that a value of a radio bearer identifier information element included in the radio bearer configuration information element does not exist in the configuration of the terminal device and that an SDAP configuration information element is included in the radio bearer configuration information element, and further notifying a higher layer that a user plane resource for a PDU session corresponding to the value of the PDU session information element has been configured based on the fact that an SDAP entity for the PDU session information element did not exist before receiving the RRC reconfiguration message, and associating the established SDAP entity with the PDU session based on the fact that an SDAP entity for the PDU session information element existed before receiving the RRC reconfiguration message.

[0098] Also, a method for a terminal device communicating with a base station device, comprising: receiving an RRC reconfiguration message including a radio bearer configuration information element from the base station device; and, based on the fact that a value of a radio bearer identifier information element included in the radio bearer configuration information element does not exist in the configuration of the terminal device and that the radio bearer configuration information element includes an SDAP configuration information element, establishing an SDAP entity if an SDAP entity for a PDU session information element included in the SDAP configuration information element does not exist; further, determining whether an SDAP entity for the PDU session information element existed before receiving the RRC reconfiguration message; and, based on the fact that an SDAP entity for the PDU session information element did not exist before receiving the RRC reconfiguration message, notifying a higher layer that user plane resources for a PDU session corresponding to the value of the PDU session information element have been configured; and, based on the fact that an SDAP entity for the PDU session information element existed before receiving the RRC reconfiguration message, associating the established SDAP entity with the PDU session.

[0099] Also, a method of a base station device communicating with a terminal device includes transmitting an RRC reconfiguration message including a radio bearer configuration information element to the terminal device, including the radio bearer configuration information element in the RRC reconfiguration message, causing the terminal device to perform processing, the processing including, based on the fact that a value of a radio bearer identifier information element included in the radio bearer configuration information element does not exist in the configuration of the terminal device and that the radio bearer configuration information element includes an SDAP configuration information element, establishing an SDAP entity if an SDAP entity for a PDU session information element included in the SDAP configuration information element does not exist, and further, This process determines whether an SDAP entity for the PDU session information element existed before receiving the RRC reconfiguration message, notifies a higher layer that user plane resources have been configured for a PDU session corresponding to the value of the PDU session information element based on the fact that an SDAP entity for the PDU session information element did not exist before receiving the RRC reconfiguration message, and associates the established SDAP entity with the PDU session based on the fact that an SDAP entity for the PDU session information element existed before receiving the RRC reconfiguration message.

[0100] The program that runs on the device according to the present invention may be a program that controls a Central Processing Unit (CPU) or the like to make a computer function so as to realize the functions of the above-mentioned embodiments according to the present invention. The program or information handled by the program is temporarily loaded into a volatile memory such as a Random Access Memory (RAM) during processing, or is stored in a non-volatile memory such as a flash memory or a Hard Disk Drive (HDD), and is read, modified, and written by the CPU as necessary.

[0101] It should be noted that a part of the device in the above-mentioned embodiment may be realized by a computer. In that case, a program for realizing this control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed to realize the control function. The "computer system" here refers to a computer system built into the device, and includes hardware such as an operating system and peripheral devices. The "computer-readable recording medium" may be any of a semiconductor recording medium, an optical recording medium, a magnetic recording medium, and the like.

[0102] Furthermore, the term "computer-readable recording medium" may include a medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and a medium that stores a program for a certain period of time, such as a volatile memory in a computer system that serves as a server or client in such a case. The above program may be one that realizes part of the above-mentioned functions, or one that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0103] Also, each functional block or feature of the device used in the above-mentioned embodiment may be implemented or executed by an electric circuit, i.e., typically an integrated circuit or a plurality of integrated circuits. The electric circuit designed to execute the functions described herein may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or a combination thereof. The general-purpose processor may be a microprocessor, or alternatively, the processor may be a conventional processor, controller, microcontroller, or state machine. The general-purpose processor or each of the aforementioned circuits may be composed of digital circuits or analog circuits. Also, when an integrated circuit technology that replaces the current integrated circuits appears due to the progress of semiconductor technology, it is possible to use an integrated circuit based on that technology.

[0104] The present invention is not limited to the above-described embodiment. In the embodiment, an example of a device is described, but the present invention is not limited to this, and can be applied to stationary or non-movable electronic devices installed indoors or outdoors, such as terminal devices or communication devices of AV equipment, kitchen equipment, cleaning / washing equipment, air conditioners, office equipment, vending machines, and other household appliances.

[0105] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes within the scope of the gist of the present invention are also included. Furthermore, the present invention can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, configurations in which elements described in the above embodiment are replaced with elements that have the same effect are also included. [Explanation of symbols]

[0106] 100 E-UTRA 102 eNB 104 EPC 106 NR 108 gNB 110 5GC 112, 114, 116, 118, 120, 124 Interface 122UE 200, 300 PHY 202, 302 MAC 204, 304 RLC 206, 306 PDCP 208, 308 RRC 310SDAP 500 Receiver 502, 602 Processing section 600 Transmitter

Claims

1. A terminal device that communicates with a base station device, A receiving unit that receives a Radio Resource Control (RRC) reconfiguration message including a Data Radio Bearer (DRB) configuration from the base station device; A processing unit, When processing the RRC reconfiguration message received by the receiving unit, the processing unit: (a) determines that a DRB identifier included in the DRB configuration does not exist in the current configuration of the terminal device; (b) determines that the DRB configuration includes a Service Data Adaptation Protocol (SDAP) configuration; and (c) determines that an SDAP entity corresponding to a PDU session indicated by a Protocol Data Unit (PDU) session information element included in the SDAP configuration does not exist. if it is determined that (a), (b), and (c) are satisfied, establishing an SDAP entity; Further, if the SDAP entity corresponding to the PDU session indicated by the PDU session information element did not exist before receiving the RRC reconfiguration message, the terminal device notifies an upper layer that user plane resources for the PDU session information element have been established.

2. A communication method for a terminal device communicating with a base station device, comprising: receiving a Radio Resource Control (RRC) reconfiguration message including a Data Radio Bearer (DRB) configuration from the base station device; When processing the received RRC reconfiguration message, (a) determine that a DRB identifier included in the DRB configuration does not exist in the current configuration of the terminal device, (b) determine that the DRB configuration includes a Service Data Adaptation Protocol (SDAP) configuration, and (c) determine that an SDAP entity corresponding to a PDU session indicated by a Protocol Data Unit (PDU) session information element included in the SDAP configuration does not exist; establishing an SDAP entity if it is determined that (a), (b), and (c) are satisfied; and notifying a higher layer that user plane resources for the PDU session information element have been established if the SDAP entity corresponding to the PDU session indicated by the PDU session information element did not exist before receiving the RRC reconfiguration message.

3. A base station device that communicates with a terminal device, A transmission unit that transmits a radio resource control (RRC) reconfiguration message including a data radio bearer (DRB) configuration to the terminal device; A processing unit that causes the terminal device to perform processing by including the DRB configuration in the RRC reconfiguration message, The process comprises: When the terminal device processes the RRC reconfiguration message received, (a) it determines that a DRB identifier included in the DRB configuration does not exist in the current configuration of the terminal device, (b) it determines that the DRB configuration includes a Service Data Adaptation Protocol (SDAP) configuration, and (c) it determines that an SDAP entity corresponding to a PDU session indicated by a Protocol Data Unit (PDU) session information element included in the SDAP configuration does not exist; establishing an SDAP entity if it is determined that (a), (b), and (c) are satisfied; Further, if the SDAP entity corresponding to the PDU session indicated by the PDU session information element does not exist before receiving the RRC reconfiguration message, notifying an upper layer that user plane resources for the PDU session information element have been established. Base station equipment.

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