Enabling paging subgrouping for user devices

Abstract

A radio access network (RAN), a core network (CN), and a user equipment (UE) may implement a method for managing paging subgrouping for a UE when the UE operates in an inactive or idle state. The method includes transmitting and / or receiving a paging subgroup configuration, determining whether the configuration should be used in paging and monitoring procedures, and monitoring or paging the UE according to the determination. The method may further include transitioning between base stations for the UE and suspending all monitoring using the paging subgroup configuration during the emergency PDU session.

Description

[Technical Field]

[0001] The present disclosure relates generally to wireless communications, and more particularly to paging user equipment (UE) when the UE operates in an inactive or idle state associated with a protocol for controlling radio resources. [Background technology]

[0002] This background discussion is provided for the purpose of generally presenting the context for the present disclosure. The work of the named inventors to the extent described in this background section, and aspects of the discussion that may not otherwise qualify as prior art at the time of filing, are not admitted, expressly or implicitly, as prior art to the present disclosure.

[0003] A user equipment (UE) can belong to a specific paging group. The Third Generation Partnership Project (3GPP) recently proposed certain paging enhancements to save power in the UE, such as dividing the paging group into subgroups and supporting subgroup paging. Further paging enhancements include using a downlink control indicator (DCI) to indicate the UE's subgroup, either in same-slot scheduling or cross-slot scheduling, using a paging early indication (PEI) or wake-up signal (WUS) to indicate the UE's subgroup, using multiple paging radio network temporary identifiers (P-RNTIs) for different subgroups, and using different time / frequency resources for different subgroups.

[0004] A UE can receive a paging request while in several states of the RRC sublayer. In particular, the RRC sublayer defines an RRC_IDLE state in which the UE does not have an active radio connection with a base station, an RRC_CONNECTED state in which the UE has an active radio connection with a base station, and an RRC_INACTIVE state to allow the UE to more quickly return to the RRC_CONNECTED state due to Radio Access Network (RAN) level base station coordination and RAN paging procedures.

[0005] In some scenarios, a UE may operate in an idle or inactive state (e.g., an RRC_IDLE or RRC_INACTIVE state) and then transition to a connected state. Generally, in the idle or inactive state, the radio connection between the UE and a radio access network (RAN) is suspended. The UE may transition to the connected state when the UE is ready to transmit uplink data (e.g., for an outgoing call or upon browser launch) or receives a paging request from a base station. To perform the transition, the UE may request the base station to establish a radio connection (e.g., by sending an RRC Setup Request message to the base station) or request the base station to resume a suspended radio connection (e.g., by sending an RRC Resume Request message to the base station), so that the base station can configure the UE to operate in the connected state.

[0006] The Packet Data Convergence Protocol (PDCP) sublayer of the radio protocol stack provides services such as user plane data transport, encryption, and integrity protection. For example, the PDCP layer defined for the Evolved Universal Terrestrial Radio Access (EUTRA) and New Radio (NR) air interfaces provides protocol data unit (PDU) sequencing in the uplink direction (from the user device, also known as the user equipment (UE), to the base station) and the downlink direction (from the base station to the UE). The PDCP sublayer also provides signaling radio bearer (SRB) services to the Radio Resource Control (RRC) sublayer. The PDCP sublayer also provides data radio bearer (DRB) services to the Service Data Adaptation Protocol (SDAP) sublayer or other protocol layers, such as the Internet Protocol (IP), Ethernet, and Internet Control Message Protocol (ICMP) layers. Generally, a UE and a base station may exchange RRC messages and non-access stratum (NAS) messages using SRBs, and may transfer data on the user plane using DRBs.

[0007] In some scenarios, different capabilities of the UE and base station related to paging subgrouping can cause the UE to miss paging requests. Furthermore, current use of paging subgrouping does not take into account the different PDU sessions that the UE can establish before paging. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] 3GPP Specification 38.413 [Non-patent document 2] 3GPP Specification 36.413 [Non-patent document 3] 3GPP Specification 38.331 [Non-patent document 4] 3GPP Specification 38.423 [Non-patent document 5] 3GPP Specification 36.423 [Non-patent document 6] 3GPP Specification 38.321 [Non-Patent Document 7] 3GPP Specification 38.213 Summary of the Invention [Means for solving the problem]

[0009] A core network (CN) configures a specific paging subgroup for a UE via a RAN including one or more base stations. Each base station may support one cell or multiple cells. The UE may camp on a cell of a base station that supports paging subgrouping for the cell. The base station may indicate to the UE in a system information block or using a suitable RRC message that the base station supports paging subgrouping for the cell, so that the UE can monitor paging DCI and / or PEI according to the paging subgroup configuration (e.g., paging subgroup configuration). Otherwise, when the base station does not indicate support for paging subgrouping for the cell, the UE monitors paging without using paging enhancements, i.e., using legacy techniques.

[0010] One exemplary embodiment of these techniques is a method implemented in a user equipment (UE) operating in a cell of a radio access network (RAN), the method including receiving, by processing hardware, a configuration of paging subgroups from the RAN, determining, by the processing hardware, whether the UE should use the configuration to monitor paging in the cell based on at least whether the cell supports paging subgrouping, and monitoring, by the processing hardware, for paging in the cell according to the determination.

[0011] Another example embodiment of these techniques is a method, implemented in a RAN, for managing paging subgrouping for a UE, the method including receiving, by processing hardware from a core network (CN), a configuration of paging subgroups for the UE, determining, by the processing hardware, that a cell in which the UE operates supports paging subgrouping, and, in response to the determination, paging, by the processing hardware, the UE according to the configuration.

[0012] Yet another exemplary embodiment of these techniques is a method, implemented in a CN, for managing paging subgrouping for a UE, the method including: sending, by processing hardware, a paging subgroup configuration to the UE via the RAN; determining, by the processing hardware, whether a message associated with the UE, destined for a base station in the RAN, should include the configuration based at least in part on whether the base station supports paging subgrouping; and sending, by the processing hardware, the message to the base station. [Brief explanation of the drawings]

[0013] [Figure 1A] FIG. 1 is a block diagram of an example system in which a base station and / or user equipment (UE) can implement the techniques of this disclosure to manage paging subgrouping between the UE and a radio access network (RAN). [Figure 1B] 1B is a block diagram of an exemplary base station including a central unit (CU) and distributed units (DU) that may operate within the system of FIG. 1A. [Figure 2] FIG. 1C is a block diagram of an example protocol stack by which the UE of FIGS. 1A-1B can communicate with a base station. [Figure 3] FIG. 10 illustrates an example scenario in which a UE determines whether to use a paging subgroup configuration from the RAN based on whether the base station's cell supports paging subgrouping. [Figure 4A] FIG. 1 illustrates a scenario in which a UE selects (or reselects) a new cell of a second base station of the RAN and the base station determines whether the new cell belongs to the same RAN notification area as cells that support paging subgrouping. [Figure 4B] FIG. 4B illustrates a scenario similar to that of FIG. 4A, but in which the UE further determines whether to use the configuration to monitor paging subgroups based on whether the UE receives a configuration from a cell. [Figure 5] FIG. 4 illustrates a scenario similar to that of FIG. 3, but in which the UE monitors paging in an inactive state. [Figure 6A] FIG. 4B illustrates a scenario similar to that of FIG. 4A, but in which the UE monitors paging in an inactive state. [Figure 6B] FIG. 6B illustrates a scenario similar to that of FIG. 6A, but in which the UE further determines whether to use the configuration to monitor paging subgroups based on whether the UE receives a configuration from a cell. [Figure 6C] 6B illustrates a scenario similar to that of FIG. 6A, but in which the UE performs a resumption procedure with a second base station, and the second base station retrieves the paging subgroup configuration from the first base station. [Figure 7A]FIG. 10 illustrates a scenario in which a UE establishes an emergency PDU session and accordingly refrains from using a paging subgroup configuration. [Figure 7B] 7B illustrates a scenario similar to that of FIG. 7A, but in which the RAN and UE release the paging subgroup configuration in response to the establishment of an emergency PDU session by the UE. [Figure 7C] 7B illustrates a scenario similar to that of FIG. 7A, but in which the UE further selects or reselects a new cell while the emergency PDU session is active. [Figure 7D] 7B illustrates a scenario similar to that of FIG. 7A, but in which the UE uses a paging subgroup configuration after the emergency PDU session ends. [Figure 8] 10 is a flow diagram of an example method implemented in a UE for determining whether to monitor for paging using a paging subgroup configuration. [Figure 9A] 1 is a flow diagram of an example method implemented in a UE for determining whether to indicate support for paging subgrouping in an uplink message based on whether the UE enables support for paging subgrouping for a cell's public land mobile network (PLMN). [Figure 9B] 9B is a flow chart of an example method for a UE to determine whether to indicate support based on whether a cell supports paging subgrouping, similar to FIG. 9A. [Figure 10] 1 is a flow chart of an example method implemented in a UE for obtaining first and second paging subgroup configurations from a CN via first and second cells, respectively; [Figure 11] 10 is a flow diagram of an example method, implemented in a UE, for determining whether the UE should update or release a first paging subgroup configuration with a second paging subgroup configuration. [Figure 12A] 10 is a flow diagram of an example method implemented in a RAN for determining whether to page a UE according to a paging subgroup configuration based on whether a cell supports paging subgrouping. [Figure 12B] 12B is a flow chart of an example method implemented in the RAN, similar to FIG. 12A, but in which the RAN further determines whether the UE has established an emergency PDU session. [Figure 13A] 10 is a flow diagram of an example method implemented in a CU for determining whether to include paging subgroup configuration in a message from a CU to a DU based on whether the DU supports paging subgroup configuration. [Figure 13B] 13B is a flowchart of an example method implemented in a CU, similar to FIG. 13A, but in which the CU further determines whether the UE has established an emergency PDU session. [Figure 13C] 13B is a flowchart of an exemplary method implemented in a CU, similar to FIG. 13A, but in which the CU further determines whether the CU supports paging subgroup configuration. [Figure 14A] 10 is a flow diagram of an example method implemented in a CN for determining whether to send a paging subgroup configuration to a base station based on whether the base station supports paging subgroups. [Figure 14B] 14B is a flowchart of an exemplary method implemented in a CN, similar to FIG. 14A, but in which the CN further determines whether the UE has established an emergency PDU session. [Figure 15] FIG. 10 is a flow diagram of an example method implemented in a CN for determining whether to send a second paging subgroup configuration to a UE via a RAN based on whether a registration request from the UE indicates support for paging subgrouping. [Figure 16] 10 is a flow diagram of an example method implemented in a CN for suspending and then resuming application of a paging subgroup configuration. [Figure 17] 10 is a flow diagram of an example method implemented in a CN for releasing a paging subgroup configuration. [Figure 18] 10 is a flow diagram of an example method for managing paging subgrouping that may be implemented in a UE. [Figure 19] 1 is a flow diagram of an example method for managing paging subgrouping that may be implemented in a RAN. [Figure 20] 1 is a flow diagram of an example method for managing paging subgrouping that may be implemented in a CN. DETAILED DESCRIPTION OF THE INVENTION

[0014] The UE, the base station, and / or the core network implement the techniques of this disclosure to utilize this feature when the UE and the base station support paging subgrouping in the cell the UE is currently operating in. When the UE or the base station does not support paging subgrouping in the cell, the UE and the base station utilize paging without paging subgrouping, e.g., legacy paging.

[0015] 1A , an exemplary wireless communication system 100 includes a UE 102, a base station (BS) 104, a base station 106, and a core network (CN) 110. The base stations 104 and 106 may operate within a RAN 105 connected to the core network (CN) 110. The CN 110 may be implemented, for example, as an evolved packet core (EPC) 111 or a fifth generation (5G) core (5GC) 160. The CN 110 may also be implemented as a sixth generation (6G) core in another example.

[0016] The base station 104 covers cell 124, and the base station 106 covers cell 126. If the base station 104 is a gNB, the cell 124 is an NR cell. If the base station 124 is an ng-eNB, the cell 124 is an Evolved Universal Terrestrial Radio Access (E-UTRA) cell. Similarly, if the base station 106 is a gNB, the cell 126 is an NR cell, and if the base station 126 is an ng-eNB, the cell 126 is an E-UTRA cell. The cells 124 and 126 can be in the same Radio Access Network Notification Area (RNA) or different RNAs. In general, the RAN 105 can include any number of base stations, each of which can cover one, two, three, or any other suitable number of cells. The UE 102 can support at least a 5G NR (or simply “NR”) or E-UTRA air interface to communicate with the base stations 104 and 106. Each of the base stations 104, 106 may be connected to the CN 110 via an interface (e.g., an S1 or NG interface). The base stations 104 and 106 may also be connected to each other via an interface (e.g., an X2 or Xn interface) for connecting NG RAN nodes to each other.

[0017] Among other components, the EPC 111 may include a Serving Gateway (SGW) 112, a Mobility Management Entity (MME) 114, and a Packet Data Network Gateway (PGW) 116. The SGW 112 is generally configured to forward user plane packets related to voice calls, video calls, Internet traffic, etc., and the MME 114 is configured to manage authentication, registration, paging, and other related functions. The PGW 116 provides connectivity from the UE to one or more external packet data networks, e.g., an Internet network and / or an Internet Protocol (IP) Multimedia Subsystem (IMS) network. The 5GC 160 includes a User Plane Function (UPF) 162, and an Access and Mobility Management Function (AMF) 164 and / or a Session Management Function (SMF) 166. Generally, the UPF 162 is configured to forward user plane packets related to voice calls, video calls, Internet traffic, etc., the AMF 164 is configured to manage authentication, registration, paging, and other related functions, and the SMF 166 is configured to manage PDU sessions.

[0018] 1 , base station 104 supports cell 124, and base station 106 supports cell 126. Cells 124 and 126 may partially overlap, such that UE 102 may select, reselect, or handover from one of cells 124 and 126 to the other. To directly exchange messages or information, base station 104 and base station 106 may support an X2 or Xn interface. In general, CN 110 may connect to any suitable number of base stations supporting NR and / or EUTRA cells.

[0019] The CN 110 may receive DL data for the UE 102. When the UE operates in an idle state (e.g., RRC_IDLE or CM-IDLE), the CN 110 determines to page the UE 102 to transmit DL data to the UE 102. In response to the determination, the CN 110 may perform a paging operation with the RAN 105 to page the UE 102 operating in the idle state. More specifically, the CN 110 may send a CN-to-BS paging message (e.g., an NG Application Protocol (NGAP) Paging message defined in 3GPP specification 38.413 or an S1 Application Protocol (S1AP) Paging message defined in 3GPP specification 36.413) to the RAN 105 to trigger the RAN 105 to send a UE paging message to the UE 102. The CN 110 includes the CN ID of the UE 102 in the NGAP paging message. For example, the CN ID may be an S-TMSI or a 5G-S-TMSI. In response to the paging message from the CN to the BS, the base station 104 of the RAN 105 generates a UE paging message (e.g., an RRC paging message defined in 3GPP specification 38.331) including the CN ID and transmits the UE paging message via the cell 124 to page the UE 102. If the base station 104 has additional cells, the base station 104 may also transmit the UE paging message via the additional cells to page the UE 102. In response to or after receiving the UE paging message from the base station 104 (e.g., via the cell 124), the idle UE 102 may perform an RRC connection establishment procedure with the base station 104 to establish an RRC connection (i.e., SRB1 and / or SRB2) with the base station 104 and transmit a Service Request message to the CN 110 via the base station 104 and the RRC connection (i.e., either SRB1 or SRB2).After receiving the Service Request message, the CN 110 may send a CN-to-BS message (e.g., a PDU Session Resources Setup Request message, a PDU Session Resources Modification Request message, or an Initial Context Setup Request message) to the base station 104 to request the base station 104 to allocate resources for the UE 102 to receive DL data. The CN 110 may include a PDU session ID and / or a quality of service (QoS) flow ID of the UE 102 in the CN-to-BS message to request the base station 104 to allocate resources for the PDU session and / or QoS flow identified by the PDU session ID and / or QoS flow ID, respectively. In response to or after receiving the CN-to-BS message, the base station 104 activates security protection for the UE 102 and performs setup for the DRB for the PDU session and / or QoS flow. The base station 104 may send a security mode command message to the UE 102 to activate security protection, and the UE 102 may respond by sending a security mode complete message to the base station 104. The base station 104 may send an RRC reconfiguration message to the UE 102 to configure DRBs for PDU sessions and / or QoS flows, and the UE 102 may respond by sending an RRC reconfiguration complete message to the base station 104.

[0020] When the UE 102 operates in an inactive state (e.g., an RRC_INACTIVE state), the CN 110 transmits DL data to the RAN 105, for example, via an NG-U connection or interface, without transmitting a CN-to-BS paging message (e.g., an NGAP paging message defined in 3GPP specification 38.413 or an S1AP paging message defined in 3GPP specification 36.413) for the UE 102 to the RAN 105. After receiving or in response to receiving the DL data, the base station 104 of the RAN 105 generates a UE paging message (e.g., an RRC paging message defined in 3GPP specification 38.331) including the RAN ID of the UE 102 and transmits the UE paging message via the cell 124 to page the UE 102. If the base station 104 has additional cells, the base station 104 can also transmit the UE paging message via the additional cells to page the UE 102. For example, the RAN ID may be an inactive radio network temporary identifier (I-RNTI). In some scenarios and implementations, the base station 104 may send a BS-to-BS paging message (e.g., an Xn Paging message defined in 3GPP specification 38.423 or an X2 Paging message defined in 3GPP specification 36.423) including the RAN ID to the base station 106 to trigger the base station 106 to page the UE 102. In response to or in accordance with the BS-to-BS paging message, the base station 106 generates a UE paging message (e.g., an RRC paging message defined in 3GPP specification 38.331) including the RAN ID and transmits the UE paging message via the cell 126. If the base station 106 has additional cells, the base station 106 may also transmit the UE paging message via the additional cells to page the UE 102.In response to or after receiving a UE paging message from the base station 104, the UE 102 can perform an RRC connection resumption procedure with the base station 104 to transition from an inactive state to a connected state (e.g., an RRC_CONNECTED state). If the UE 102 is enabled for early data communication (also called small data transmission) by the RAN 105 and the UE paging message indicates that the UE 102 should perform early data communication (e.g., mobile terminating early data transmission (EDT)), the UE 102 in the inactive state performs early data communication with the base station 104 without a state transition. During early data communication, the UE 102 can send a UL RRC message (e.g., an RRC Resume Request message) including a message authentication code for integrity (MAC-I) to the base station 104 in response to the UE paging message. In the UL RRC message, the UE 102 may include an indication to indicate EDT or may have a value indicating EDT to prevent the base station 104 from transitioning the UE 102 to a connected state. After receiving the UL RRC message, the base station 104 may transmit DL data to the UE 102 operating in an inactive state.

[0021] The base station 104 comprises processing hardware 130, which may include one or more general-purpose processors (e.g., CPUs) and non-transitory computer-readable memory that stores instructions executed by the one or more general-purpose processors. Additionally or alternatively, the processing hardware 130 may include a dedicated processing unit. The processing hardware 130 of an exemplary implementation includes a medium access control (MAC) controller 132 configured to perform random access procedures with one or more user devices, receive uplink (UL) MAC protocol data units (PDUs) from one or more user devices, and transmit downlink (DL) MAC PDUs to one or more user devices. The processing hardware 130 may also include a packet data convergence protocol (PDCP) controller 134, configured to transmit PDCP PDUs according to which the base station 104 can transmit data in the downlink direction in some scenarios and receive PDCP PDUs according to which the base station 104 can receive data in the uplink direction in other scenarios. The processing hardware may further include an RRC controller 136 for implementing procedures and messaging at the RRC sublayer of a protocol communication stack. The processing hardware 130 of the exemplary implementation includes a paging controller 138 configured to manage paging operations with one or more UEs operating in an RRC_INACTIVE state or an RRC_IDLE state. The base station 106 may include generally similar components. In particular, components 142, 144, 146, and 148 may be similar to components 132, 134, 136, and 138, respectively.

[0022] The UE 102 comprises processing hardware 150, which may include one or more general-purpose processors, such as a CPU, non-transitory computer-readable memory that stores machine-readable instructions executable on the one or more general-purpose processors, and / or dedicated processing units. The processing hardware 150 of an exemplary implementation includes a paging controller 158 configured to manage paging operations when the UE 102 operates in an RRC_IDLE state or an RRC_INACTIVE state. The processing hardware 150 of an exemplary implementation includes a medium access control (MAC) controller 152 configured to perform random access procedures with base stations, transmit uplink MAC protocol data units (PDUs) to base stations, and receive downlink MAC PDUs from base stations. The processing hardware 150 may also include a PDCP controller 154 configured to transmit PDCP PDUs according to which the UE 102 can transmit data in the uplink direction in some scenarios and receive PDCP PDUs according to which the UE 102 can receive data in the downlink direction in other scenarios. The processing hardware may further include an RRC controller 156 for implementing procedures and messaging at the RRC sublayer of the protocol communications stack.

[0023] 1B depicts an exemplary distributed or disaggregated implementation of any one or more of the base stations 104, 106. In this implementation, the base station 104A, 104B, 106A, or 106B includes a central unit (CU) 172 and one or more DUs 174. The CU 172 includes processing hardware, such as one or more general-purpose processors (e.g., CPUs), computer-readable memory that stores machine-readable instructions executable on the general-purpose processors, and / or dedicated processing units. For example, the CU 172 may include a PDCP controller, an RRC controller, and / or a paging controller, such as the PDCP controllers 134, 144, the RRC controllers 136, 146, and / or the paging controllers 138, 148. In some implementations, the CU 172 may include a radio link control (RLC) controller configured to manage or control one or more RLC operations or procedures. In other implementations, the CU 172 does not include an RLC controller.

[0024] Each of the DUs 174 also includes processing hardware, which may include one or more general-purpose processors (e.g., CPUs) and computer-readable memory that stores machine-readable instructions executable on the one or more general-purpose processors, and / or special-purpose processing units. For example, the processing hardware may include a MAC controller (e.g., MAC controllers 132, 142) configured to manage or control one or more MAC operations or procedures (e.g., random access procedures) and / or an RLC controller configured to manage or control one or more RLC operations or procedures. The processing hardware may also include a physical layer controller configured to manage or control one or more physical layer operations or procedures.

[0025] In some implementations, the CU 172 may include a logical node CU-CP 172A that hosts the control plane portion of the PDCP protocol for the CU 172. The CU 172 may also include a logical node CU-UP 172B that hosts the user plane portion of the PDCP protocol and / or the Service Data Adaptation Protocol (SDAP) protocol for the CU 172. The CU-CP 172A may transmit control information (e.g., RRC messages, F1 application protocol messages), and the CU-UP 172B may transmit data packets (e.g., SDAP PDUs or Internet Protocol packets).

[0026] The CU-CP 172A may be connected to multiple CU-UPs 172B through an E1 interface. The CU-CP 172A selects an appropriate CU-UP 172B for a requested service for the UE 102. In some implementations, a single CU-UP 172B may be connected to multiple CU-CPs 172A through an E1 interface. If the CU-CP and DU belong to a gNB, the CU-CP 172A may be connected to one or more DUs 174 through an F1-C interface and / or an F1-U interface. If the CU-CP and DU belong to an ng-eNB, the CU-CP 172A may be connected to one or more DUs 174 through a W1-C interface and / or a W1-U interface. In some implementations, one DU 174 may be connected to multiple CU-UPs 172B under the control of the same CU-CP 172A. In such an implementation, connectivity between the CU-UP 172B and the DU 174 is established by the CU-CP 172A using Bearer Context Management functionality.

[0027] FIG. 2A illustrates a simplified example protocol stack 200 by which a UE 102 may communicate with an eNB / ng-eNB or gNB (e.g., one or more of the base stations 104, 106).

[0028] In the example stack 200, a EUTRA physical layer (PHY) 202A provides transport channels to a EUTRA MAC sublayer 204A, which in turn provides logical channels to a EUTRA RLC sublayer 206A. Furthermore, the EUTRA RLC sublayer 206A provides RLC channels to a EUTRA PDCP sublayer 208 and, possibly, to a NR PDCP sublayer 210. Similarly, a NR PHY 202B provides transport channels to a NR MAC sublayer 204B, which in turn provides logical channels to a NR RLC sublayer 206B. Furthermore, the NR RLC sublayer 206B provides data transfer services to a NR PDCP sublayer 210. The NR PDCP sublayer 210, in turn, can provide data transfer services to a service data adaptation protocol (SDAP) 212 or a radio resource control (RRC) sublayer (not shown in FIG. 2A ). In some implementations, the UE 102 supports both the EUTRA stack and the NR stack, as shown in Figure 2A, to support handover between EUTRA and NR base stations and / or to support DC on the EUTRA and NR interfaces. Additionally, as shown in Figure 2A, the UE 102 can support layering of the NR PDCP 210 on the EUTRA RLC 206A and the SDAP sublayer 212 on the NR PDCP sublayer 210.

[0029] The EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 receive packets that may be referred to as service data units (SDUs) (e.g., from an Internet Protocol (IP) layer layered directly or indirectly on the PDCP layer 208 or 210) and output packets that may be referred to as protocol data units (PDUs) (e.g., to the RLC layer 206A or 206B). For simplicity, this disclosure will refer to both SDUs and PDUs as "packets" unless the distinction between SDUs and PDUs is important.

[0030] In the control plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 can provide, for example, a signaling radio bearer (SRB) or an RRC sublayer (not shown in FIG. 2) for exchanging RRC messages or non-access stratum (NAS) messages. In the user plane, the EUTRA PDCP sublayer 208 and the NR PDCP sublayer 210 can provide a data radio bearer (DRB) for supporting the exchange of data. The data exchanged over the NR PDCP sublayer 210 can be SDAP PDUs, Internet Protocol (IP) packets, or Ethernet packets.

[0031] 2B , the radio protocol stack can be functionally divided. The CU of any IAB donor 108A, 108B, or 108C can retain all control and upper layer functions (e.g., RRC 214, SDAP 212, NR PDCP 210), while lower layer operations (e.g., NR RLC 206B, NR MAC 204B, and NR PHY 202B) are delegated to the DU at the IAB node 104. To support connectivity to 5GC, the NR PDCP 210 provides SRBs to the RRC 214, which in turn provides DRBs to the SDAP 212 and provides SRBs to the RRC 214.

[0032] 3-7D are message sequences for an example scenario in which a UE determines whether to monitor paging using a paging subgroup configuration. Generally, events in FIGS. 3-7D that are similar are labeled with similar reference numbers (e.g., event 392 in FIG. 3 is similar to events 491 / 492 in FIGS. 4A-4B and event 592 in FIG. 5; event 394 in FIG. 3 is similar to event 494 in FIGS. 4A-4B, event 594 in FIG. 5, event 694 in FIGS. 6A-6C, and event 794 in FIGS. 7A-7D), and differences are discussed below, where appropriate. Except for the differences shown in the figures and discussed below, any of the alternative implementations discussed in connection with particular events (e.g., with respect to messaging and processing) may also apply to events labeled with similar reference numbers in the other figures.

[0033] 3, in a scenario 300, the UE 102 initially operates in a connected state (e.g., RRC_CONNECTED) with the base station 104 via the cell 124 (304). The UE 102 may receive (302) system information (e.g., one or more system information blocks (SIBs)) regarding the cell 124 from the base station 104 before or after entering the connected state (304). In some implementations, the UE 102 receives (302) the SIB that includes an indication of whether a particular cell supports paging subgrouping and / or other or additional paging enhancements.

[0034] While the UE 102 is operating in a connected state, the UE 102 transmits a Registration Request message to the base station 104 including information indicating support for paging subgrouping (306). The base station 104, in turn, transmits a BS-to-CN message including the Registration Request message to the CN 110 (e.g., to the AMF 164 or the MME 114) (308). After the CN 110 receives the information indicating support for paging subgrouping, the CN 110 may determine to configure a first configuration of paging subgroups (or simply a “paging subgroup configuration”) in response to or according to the information. In some implementations, the first configuration of paging subgroups includes a first paging subgroup ID that configures the UE 102 to belong to the first paging subgroup. In response to the determination, the CN 110 generates a Registration Accept message including the first configuration of paging subgroups and transmits a first CN-to-BS message including the Registration Accept message to the base station 104 (310). The base station 104 then in turn sends (312) a Registration Accept message to the UE 102. In response, the UE 102 may send (314) a Registration Complete message to the base station 104, which in turn sends (316) a Registration Complete message to the CN 110.

[0035] After a period of data inactivity for the UE 102, the base station 104 may determine that neither the base station 104 nor the UE 102 transmitted any data in the downlink or uplink direction, respectively, during the period. In response to the determination, the base station 104 transmits an RRC release message (e.g., an RRCRelease message) to the UE 102 (318). The UE 102 transitions to an idle state (e.g., an RRC_IDLE state) in response to receiving the RRC release message and operates in the idle state (320). In some implementations (not shown), the CN 110 transmits an additional CN-to-BS message to the base station 104 indicating to the base station 104 that it is transitioning the UE 102 to the idle state (e.g., an RRC_IDLE state). In such a case, the base station 104 transmits an RRC release message to the UE 102 in response to the additional CN-to-BS message. In some implementations, the UE 102 may receive 302 system information regarding the cell 124 after transitioning to the idle state.

[0036] Events 304, 306, 308, 310, 312, 314, 316, and 318 are collectively referred to as a registration procedure 392 in FIG. 3. In some implementations, other UEs (e.g., UE 101 and / or UE 103) may receive system information about cell 124, perform registration procedures with CN 110 via base station 104, and enter idle states, similar to events 302, 392, and 320. For example, CN 110 may send a first configuration of paging subgroups to UE 101 during the registration procedure with UE 101. That is, UE 101 and UE 102 belong to the same paging subgroup (i.e., the first paging subgroup) identified by a first paging subgroup ID. In another example, CN 110 may send a second configuration of paging subgroups to UE 103 during the registration procedure with UE 103, the second configuration including a second paging subgroup ID. In other words, the UE 103 belongs to a second paging subgroup identified by a second paging subgroup ID and different from the first paging subgroup. Furthermore, the CN 110 may transmit a third paging subgroup configuration including a third paging subgroup ID to the UE 101 during the registration procedure with the UE 101. That is, the UE 101 belongs to a third paging subgroup identified by the third paging subgroup ID and different from the first and second paging subgroups. Alternatively, the CN 110 does not transmit a paging subgroup configuration to the UE 101 during the registration procedure with the UE 101. In this case, the UE 101 does not belong to a paging subgroup.

[0037] In some implementations, the BS-to-CN message and the first CN-to-BS message are NG Application Protocol (NGAP) messages. For example, the BS-to-CN message is an Initial UE Message or an Uplink NAS Transport message. In another example, the first CN-to-BS message is an Initial Context Setup Request message or a Downlink NAS Transport message. In some implementations, the additional CN-to-BS message is an NGAP message. For example, the additional CN-to-BS message is a UE Context Release Command message.

[0038] After transitioning from the connected state to the idle state, the idle UE 102 monitors for paging. The idle UE 102 determines whether the cell 124 (or base station 104) supports paging subgrouping (328). If the idle UE 102 determines that the cell 124 (or base station 104) supports paging subgrouping, the UE 102 uses the first paging subgroup configuration to monitor for paging (330).

[0039] In some implementations, the UE 102 receives the first paging DCI and a cyclic redundancy check (CRC) of the first paging DCI on a physical downlink control channel (PDCCH) on the cell 124, regardless of whether the cell 124 (or base station 104) supports paging subgrouping (338). The UE 102 verifies whether the CRC is valid using the P-RNTI. If the UE 102 determines that the CRC is not valid, the UE 102 may discard the first paging DCI. If the cell 124 (or base station 104) supports paging subgrouping and the UE 102 determines that the CRC is valid (similar to FIGS. 8 and 9B below), the UE 102 determines whether the first paging DCI indicates a first paging subgroup ID. If the first paging DCI indicates the first paging subgroup ID, the UE 102 attempts to receive a physical downlink shared channel (PDSCH) transmission in accordance with the first paging DCI. If the UE 102 receives the PDSCH transmission, the UE 102 decodes the PDSCH transmission to obtain a paging message (340). If the cell 124 (or base station 104) supports paging subgrouping and the first paging DCI does not indicate the first paging subgroup ID, the UE 102 may refrain from receiving or attempting to receive the PDSCH transmission in accordance with the first paging DCI. Alternatively, if the first paging DCI does not indicate the first paging subgroup ID, the UE 102 may (attempt to) receive the PDSCH transmission in accordance with the first paging DCI and then discard the PDSCH transmission.

[0040] In some implementations, if the cell 124 (or base station 104) supports paging subgrouping, the base station 104 may include a subgroup field in the first paging DCI to indicate a paging subgroup ID for paging UEs associated with the paging subgroup (similar to FIGS. 8 and 9B below). For example, the base station 104 may indicate a first paging subgroup ID, a second paging subgroup ID, and / or a third paging subgroup ID in the first paging DCI. In some implementations, the first paging subgroup configuration may configure a P-RNTI (value) (i.e., a P-RNTI specific to the subgroup). Similarly, each of the second / third paging subgroup configurations may configure a specific P-RNTI (value) that is different from each other and from the P-RNTI (value) of the first paging subgroup configuration. In other implementations, the UE 102 may determine or derive the P-RNTI (value) from the first paging subgroup ID. If UE 101 receives the first paging subgroup configuration, UE 101 may determine or derive the same P-RNTI(value) as UE 102. If UE 101 receives the third paging subgroup configuration, UE 101 may determine or derive a second P-RNTI value from the second paging subgroup ID. Similarly, UE 103 may determine or derive a third P-RNTI(value) from the second paging subgroup ID. The P-RNTI(value), second P-RNTI(value), and third P-RNTI(value) of UE 102 are different. In other implementations, the P-RNTI (value) is predefined in a 3GPP specification (e.g., 3GPP specification 38.321), and the UEs (e.g., UE 101, UE 102, and UE 103) receive the paging DCI using the predefined P-RNTI (value).

[0041] In a further implementation, the base station 104 may include an indication in the system information (see event 302) to indicate that the cell 124 (or base station 104) supports paging subgrouping. If the cell 124 does not support paging subgrouping, the base station 104 does not include an indication in the system information. Thus, the UE 102 may determine that the cell 124 (or base station 104) supports paging subgrouping if the system information includes the indication. In other implementations, the base station 104 may include an indication in the RRC release message (see event 318) to indicate that the cell 124 (or base station 104) supports paging subgrouping. If the cell 124 does not support paging subgrouping, the base station 104 does not include an indication in the RRC release message. Thus, the UE 102 may determine that the cell 124 (or base station 104) supports paging subgrouping if the RRC release message includes the indication.

[0042] In other implementations, if the cell 124 (or base station 104) supports paging subgrouping, the UE 102 attempts to receive or detect a PEI (not shown) before attempting to receive the paging DCI. In some implementations, the PEI may be associated with a first paging subgroup ID. In some implementations, the UE 102 may determine or derive (a sequence or signal of) the PEI from the first paging subgroup ID. If the UE 102 receives or detects the PEI, the UE 102 may receive (or attempt to receive) a second paging DCI and a CRC of the second paging DCI on the PDCCH on the cell 124, similar to event 338. In some implementations, the second paging DCI includes one or more paging subgroup IDs, similar to the first paging DCI. The UE 102 receives the second paging DCI in a manner similar to receiving the first paging DCI, as described above. In other implementations, the base station 104 may not include a subgroup field in the second paging DCI, which is similar to the first paging DCI. The UE 102 uses the P-RNTI to verify whether the CRC is valid. If the UE 102 determines that the CRC is valid, the UE 102 attempts to receive a PDSCH transmission according to the second paging DCI. If the UE 102 receives the PDSCH transmission, the UE 102 decodes the PDSCH transmission to obtain a paging message, similar to event 340. If the UE 102 determines that the CRC is not valid, the UE 102 discards the second paging DCI. In some implementations, the PEI signal may be a wake-up signal for paging (WUS).

[0043] In yet other implementations, if the cell 124 (or base station 104) supports paging subgrouping, the UE 102 attempts to receive or detect a paging DCI or PEI on time and / or frequency resources specific to a first paging subgroup ID. The UE 102 determines the time and / or frequency resources according to the first paging subgroup configuration. For example, the first paging subgroup configuration may include configuration parameters that configure the time and / or frequency resources for the UE 102 to receive the paging DCI or PEI (including the first / second paging DCI). In another example, the UE 102 may derive the time and / or frequency resources for receiving the paging DCI and / or PEI (including the first / second paging DCI) from the first paging subgroup configuration. In some implementations, the time and / or frequency resources may be paging occasions (POs) specific to a subgroup that are a subset of the POs monitored by the UE 102, as described below. Similarly, if the UE 101 receives the first paging subgroup configuration, the UE 101 attempts to receive or detect a paging DCI or PEI on the time and / or frequency resources specific to the first paging subgroup ID. If the UE 101 receives the third paging subgroup configuration, the UE 101 attempts to receive or detect a paging DCI or PEI on the time and / or frequency resources specific to the third paging subgroup ID. Similarly, the UE 103 attempts to receive or detect a paging DCI or PEI on the time and / or frequency resources specific to the second paging subgroup ID.

[0044] Alternatively, the UE 102 attempts to receive or detect the first / second paging DCI or PEI on a time and / or frequency resource (i.e., PO) that is not specific to a subgroup. The UE monitors the PO every DRX cycle. A PO is a set of PDCCH monitoring opportunities and may consist of multiple time slots (e.g., subframes or OFDM symbols) in which paging DCI is transmitted (3GPP Specification 38.213). A paging frame (PF) is a radio frame and may include one or more POs or the start of a PO. In some implementations, the UE 102 may determine the paging occasion (PO) and paging frame (PF) according to the formula below. Then, the UE 102 determines a PO specific to a subgroup. The base station 104 may also determine the PO and PF according to the formula below. SFN of PF is (SFN + PF_offset) mod T = (T div N)*(UE_ID mod N) is determined by. The index (i_s) indicating the index of PO is i_s = floor (UE_ID / N) mod Ns is determined by.

[0045] The PDCCH monitoring occasions for paging are determined according to the pagingSearchSpace specified in 3GPP specification 38.213, and firstPDCCH-MonitoringOccasionOfPO and nrofPDCCH-MonitoringOccasionPerSSB-InPO when configured as specified in 3GPP specification 38.331. When SearchSpaceId = 0 is configured for the pagingSearchSpace, the PDCCH monitoring occasions for paging are the same as those for RMSI, as defined in clause 13 of 3GPP specification 38.213.

[0046] When SearchSpaceId = 0 is configured for pagingSearchSpace, Ns is either 1 or 2. For Ns = 1, there is only one PO starting from the first PDCCH monitoring opportunity for paging in the PF. For Ns = 2, the PO is either in the first frame (i_s = 0) or in the second frame (i_s = 1) of the PF.

[0047] When a non-zero SearchSpaceId is configured for pagingSearchSpace, the UE monitors the (i_s + 1)th PO. PO is a set of "S*X" consecutive PDCCH monitoring opportunities, where "S" is the number of actually transmitted SSBs determined according to ssb-PositionsInBurst in SIB1, and X is nrofPDCCH-MonitoringOccasionPerSSB-InPO, if configured, or equal to 1 otherwise. The [x*S+K]th PDCCH monitoring opportunity for paging in PO corresponds to the Kth transmitted SSB, where x=0, 1,...X-1, and K=1, 2,...,S. PDCCH monitoring opportunities for paging that do not overlap with UL symbols (determined according to tdd-UL-DL-ConfigurationCommon) are numbered sequentially starting from 0, starting with the first PDCCH monitoring opportunity for paging in the PF. When firstPDCCH-MonitoringOccasionOfPO exists, the starting PDCCH monitoring opportunity number of the (i_s + 1)th PO is the (i_s + 1)th value of the firstPDCCH-MonitoringOccasionOfPO parameter; otherwise, the starting PDCCH monitoring opportunity number of the (i_s + 1)th PO is equal to i_s * S * X. If X > 1, when the UE detects a PDCCH transmission addressed to P-RNTI within that PO, the UE does not need to monitor subsequent PDCCH monitoring occasions of this PO.

[0048] In some implementations, a PO associated with a PF may start within or after the PF. In some implementations, a PDCCH monitoring opportunity for a PO may span multiple radio frames. When a non-zero SearchSpaceId is configured for paging-SearchSpace, a PDCCH monitoring opportunity for a PO may span multiple periods of the paging search space.

[0049] For the calculation of the above PF and i_s, the following parameters are used: (i) T refers to the UE's DRX cycle (T is determined by the shortest value between the UE-specific DRX value, if configured by RRC and / or higher layers, and the default DRX value broadcast in the system information. In RRC_IDLE state, if no UE-specific DRX is configured by higher layers, the default value is applied); (ii) N refers to the number of total paging frames within T; (iii) Ns refers to the number of paging occasions in the PF; (iv) PF_offset refers to the offset used to determine the PF; and (v) UE_ID refers to the 5G-S-TMSI (e.g., the 5G-S-TMSI of the UE 102) mod 1024.

[0050] The parameters Ns, nAndPagingFrameOffset, nrofPDCCH-MonitoringOccasionPerSSB-InPO and the length of the default DRX cycle are signaled in SIB1. The values ​​of N and PF_offset are derived from the parameter nAndPagingFrameOffset defined in 3GPP specification 38.331. The parameter first-PDCCH-MonitoringOccasionOfPO is signaled in SIB1 for paging in the initial downlink bandwidth part (BWP). For paging in a downlink BWP other than the initial downlink BWP, the parameter first-PDCCH-MonitoringOccasionOfPO is signaled in the corresponding BWP configuration.

[0051] If the UE 102 determines that the cell 124 does not support paging subgrouping, the UE 102 refrains from using the first paging subgroup configuration to monitor paging (332) and monitors paging using a technique without paging subgrouping. In some implementations, the UE 102 may monitor the PO on the cell 124 according to the above equation. In some scenarios or implementations, the UE 102 may receive a third paging DCI and a CRC of the third paging DCI on the PDCCH of the PO on the cell 124 (342). The UE 102 verifies whether the CRC is valid using the P-RNTI. The third paging DCI does not include a subgroup field. If the UE 102 determines that the CRC is valid, the UE 102 attempts to receive a PDSCH transmission according to the third paging DCI. If the UE 102 receives the PDSCH transmission, the UE 102 decodes the PDSCH transmission to obtain the paging message (344).

[0052] Later, the CN 110 determines to page the UE 102, for example, for a mobile terminated call or to send DL data to the UE 102. In response to the determination, the CN 110 transmits a second CN-to-BS message to the base station 104 including a first configuration of paging subgroups (334). In the second CN-to-BS message, the CN 110 of some implementations includes the NAS ID of the UE 102, one or more capabilities of the UE 102 for paging, and / or paging assistance information to page the UE 102. In some implementations, the NAS ID may be an S-TMSI or a 5G-S-TMSI. In one implementation, the CN 110 includes the NAS ID in the Registration Accept message 310. In another implementation, the CN 110 may transmit a DL NAS message including the NAS ID to the UE 102 via the RAN 105 before the registration procedure 392.

[0053] In some implementations, a UE paging capability IE (e.g., a UE Radio Paging Information IE) includes one or more capabilities for paging, and the CN 110 includes the UE paging capability IE in a message from the second CN to the BS. In some implementations, a UE full capability IE (e.g., a UE-NR-Capability IE) of the UE 102 includes one or more capabilities. The UE full capability IE includes one or more capabilities of the UE paging capability IE as well as other capabilities. In some implementations, the CN 110 may receive the UE paging capability IE and / or the UE full capability IE from the RAN 105 (e.g., a base station 104 or a base station 106). In other implementations, the CN 110 may pre-store the UE full capability IE. In such implementations, the CN 110 either pre-stores the UE paging capability IE or dynamically generates the UE paging capability IE from the UE full capability IE. In some implementations, the CN 110 may associate a capability ID with the UE overall capability IE and / or the UE paging capability.

[0054] In some implementations, the one or more capabilities include a frequency band list for paging (e.g., a supportedBandListNRForPaging field) that includes frequency bands supported by the UE 102. In some implementations, the UE full capabilities IE includes a full frequency band list (e.g., a supportedBandListNR field) that includes all frequency bands supported by the UE 102. In some implementations, the UE 102 may predetermine or preconfigure the full frequency bands according to a public land mobile network (PLMN) ID. The PLMN ID may be the PLMN ID of the serving cell (e.g., cell 124) or the home PLMN ID of the universal subscriber identity module (USIM) in the UE 102. In other implementations, the UE 102 may predetermine or preconfigure the full frequency bands according to the hardware capabilities of the UE 102. The RAN 105 or the CN 110 generates the frequency band list for paging from the full frequency band list. In some implementations, the RAN 105 or the CN 110 may include a subset of all frequency bands in the frequency band list for paging. For example, the RAN 105 or the CN 110 may select from the all frequency bands the frequency bands supported by the RAN 105. In other implementations, the RAN 105 or the CN 110 may include all frequency bands in the frequency band list for paging.

[0055] In other implementations, the one or more capabilities include one or more downlink scheduling slot offset capabilities (e.g., dl-SchedulingOffset-PDSCH-TypeA-FDD-FR1-r15, dl-SchedulingOffset-PDSCH-TypeA-TDD-FR1-r15, dl-SchedulingOffset-PDSCH-TypeB-FDD-FR1-r15, and / or dl-SchedulingOffset-PDSCH-TypeB-FDD-FR1-r15) to indicate that the UE 102 supports cross-slot scheduling. In yet other implementations, the one or more capabilities include a single capability field / IE to indicate support for PEI signaling while the UE 102 operates in an idle or inactive state (e.g., RRC_INACTIVE). Alternatively, the one or more capabilities include a first capability field / IE and a second capability field / IE for indicating support for PEI signaling while the UE 102 operates in an idle state and support for PEI signaling while the UE 102 operates in an inactive state, respectively.

[0056] In some implementations, the paging assistance information includes a paging discontinuous reception (DRX) configuration, a paging priority, a paging origination, and / or a tracking area identity (TAI) list for paging. The paging DRX information includes a paging DRX cycle value. The paging DRX configuration may be paging discontinuous reception (DRX) information (e.g., a Paging DRX IE) or paging extended DRX (eDRX) information (e.g., a Paging eDRX Information IE). In some implementations, the paging eDRX information includes a paging eDRX cycle value and / or a paging time window value.

[0057] In some implementations, the message from the second CN to the BS is an NGAP Paging message as described in 3GPP specification 38.413. In some implementations, the CN 110 includes the paging DRX information or paging eDRX information in one of the Registration Accept message 310 or the DL NAS message.

[0058] In response to or after receiving the message from the second CN to the BS, the base station 104 may determine (336) to page the UE 102 according to the first paging subgroup configuration if the cell 124 (or base station 104) supports paging subgrouping. In response to the determination, the base station 104 transmits (338) a PEI and / or the first / second paging DCI and a CRC of the first / second paging DCI on the PDCCH, as described above. After transmitting the first / second paging DCI, the base station 104 transmits (340) a Paging message that is received by the UE 102, as described above.

[0059] In response to or after receiving the message from the second CN to the BS, the base station 104 may determine (337) to page the UE 102 without using the first paging subgroup configuration if the cell 124 (or base station 104) does not support paging subgrouping. In response to the determination, the base station 104 transmits (342) a third paging DCI and a CRC of the third paging DCI on the PDCCH, as described above. After transmitting the third paging DCI, the base station 104 transmits (344) a paging message that is received by the UE 102, as described above.

[0060] In some implementations, the UE 102 indicates support for a paging DCI indicating a paging subgroup (e.g., support for a paging DCI including a subgroup field) in the UE overall capabilities IE. In some implementations, the CN 110 includes an indication of support in the paging capabilities IE. In such implementations, the base station 104 may indicate the first paging subgroup in the paging DCI (e.g., the first / second paging DCI described above) according to the indication of support. If the base station 104 does not receive an indication of support, the base station 104 may not indicate the first paging subgroup ID in the first paging DCI.

[0061] In some implementations, the UE 102 indicates support for the PEI in the UE Capabilities IE. In some implementations, the CN 110 includes an indication of support in the Paging Capabilities IE. In such implementations, the base station 104 may transmit a PEI corresponding to the first paging subgroup ID according to the indication of support, as described above. If the base station 104 does not receive an indication of support, the base station 104 does not transmit a PEI for the UE 102.

[0062] In some implementations, the UE 102 indicates support for the subgroup-specific P-RNTI in the UE Overall Capabilities IE. In some implementations, the CN 110 includes an indication of support in the Paging Capabilities IE. In such implementations, the base station 104 may generate a paging DCI (e.g., the first / second paging DCI described above) and a CRC for the paging DCI, scramble the CRC with the subgroup-specific P-RNTI, and transmit the paging DCI and CRC on the PDCCH as described above.

[0063] Events 336, 337, 338, 340, 342, and 344 are collectively referred to in Figure 3 as enhanced or legacy paging procedures 396. Events 336, 338, and 340 are collectively referred to in Figure 3 as enhanced paging procedures 398, and events 337, 342, and 344 are collectively referred to in Figure 3 as legacy paging procedures 399.

[0064] When the UE 102 receives (340, 344) the paging message via the cell 124, the UE 102 confirms that the NAS ID addresses the UE 102. In response to the confirmation, the UE 102 may initiate a paging response procedure (e.g., a service request procedure) to respond to the paging message. In response to the initiation, the UE 102 performs an RRC connection establishment procedure with the base station 104 via the cell 124 (not shown). To perform the RRC connection establishment procedure, the UE 102 transmits an RRC request message (e.g., an RRCConnectionRequest or RRCSetupRequest message) to the base station 104 via the cell 124. In response, the base station 104 may transmit an RRC response message (e.g., an RRCConnectionSetup or RRCSetup message) to the UE 102 via the cell 124. The UE 102 may send an RRC completion message (e.g., an RRCConnectionSetupComplete or RRCSetupComplete message) to the base station 104 via the cell 124. The UE 102 transitions to a connected state (e.g., an RRC_CONNECTED state) in response to the RRC response message. After the UE 102 transitions to the connected state, the base station 104 may perform a security mode procedure with the UE 102 via the cell 124 to activate security (e.g., integrity protection and / or ciphering) for data communication between the UE 102 and the base station 104. After activating security, the base station 104 may perform at least one RRC reconfiguration procedure with the UE 102 via the cell 124 to configure a signaling radio bearer (SRB) and / or a data radio bearer (DRB). The UE 102 may then communicate (e.g., transmit and / or receive) data with the CN 110 via the base station 104. The data may include user plane data packets (e.g., IP packets) and / or control plane messages (e.g., NAS messages).In some implementations, the UE 102 communicates user plane data packets over DRBs with the base station 104, and the base station 104 conveys the user plane data packets to the CN 110. In other implementations, the UE 102 communicates control plane messages over SRBs with the base station 104, and the base station 104 conveys the control plane messages to the CN 110.

[0065] 4A , the UE 102 in scenario 400A determines whether to use a paging subgroup configuration when operating in a cell of a base station 106 (e.g., cell 126) before the UE 102 selects (or reselects) a cell of a base station 104 (e.g., cell 124). The UE 102 then determines whether the base station 104 supports paging subgrouping in cell 124 based on the relationship between cell 124 and cell 126, e.g., whether these cells belong to a tracking area.

[0066] The UE 102 initially performs a registration procedure 491 with the base station 106 and the core network 110. The registration procedure 491 may be similar or identical to the registration procedure 392 of Figure 3. As in Figure 3, the UE 102 may initially operate in a connected state (e.g., RRC_CONNECTED) within the cell 126 of the base station 106. In some implementations, the UE 102 receives 402 system information in the cell 126 from the base station 106 before or after entering the connected state.

[0067] After performing the registration procedure 491, the UE 102 may operate 420 in an idle state (e.g., RRC_IDLE). In some implementations, the UE 102 and the base station 106 perform an enhanced or legacy paging procedure 494, for example, in response to receiving 403 a CN-to-BS message from the CN 110. In some implementations, the enhanced or legacy paging procedure 494 is similar to the paging procedure 396 of FIG. 3. More specifically, the enhanced paging procedure is similar to the paging procedure 398, and the legacy paging procedure is similar to the paging procedure 399.

[0068] The UE 102 then selects (or reselects) 422 the cell 124 of the base station 104. The UE may receive 424 system information regarding the cell 124 from the base station 104, similar to event 302.

[0069] The UE 102 determines (428) whether to use (430) or refrain from using (432) the paging subgroup configuration to monitor paging. In some implementations, the UE 102 makes the determination based on whether the cell 124 belongs to the same tracking area as the cell 126. The UE 102 may determine from the system information 402 and 424 that the cells 124 and 126 belong to the same tracking area. If the UE 102 determines that the cells 124 and 126 are in the same tracking area, the UE 102 may determine that the cell 124 supports paging subgrouping. Thus, in this case, the UE 102 determines (428) whether the same MME or AMF controls the cells 124 and 126 and accordingly uses (or does not use) the enhanced paging technique in all controlled cells. In other implementations, the UE 102 makes (428) the determination based on the system information the UE 102 received at event 424, similar to event 328.

[0070] In some implementations, the base station 106 performs an enhanced or legacy paging procedure 494 with the UE 102 in response to receiving a downlink data packet from the CN 110 instead of a CN-to-BS message, such as when the UE 102 operates in an idle state with the RRC connection suspended. The downlink data packet may be a user plane data packet. In some implementations, the UE 102 makes the determination based on whether the cell 124 belongs to the same RAN Notification Area (RNA) as the cell 126. If the UE 102 determines that the cells 124 and 126 are in the same RNA, the UE 102 may determine that the cell 124 supports paging subgrouping. Thus, in this case, the UE 102 determines 428 whether the same MME or AMF controls the cells 124 and 126 and uses the enhanced paging technique in all cells accordingly. In some implementations, the base station 104 may receive a tunnel packet from the CN 110 (e.g., the UPF 162) that includes a downlink data packet and a tunnel endpoint ID (TEID) that the base station 104 assigned for the UE 102. The base station 104 may determine from the TEID that the downlink data packet addresses the UE 102 and, in response to the determination, determine to page the UE 102.

[0071] If the UE 102 determines (428) that the cell 124 does not support paging subgrouping, the UE 102 refrains from using the paging subgroup configuration to monitor paging (432). If the UE 102 determines (428) that the cell 124 does support paging subgrouping, the UE 102 uses (430) the paging subgroup configuration to monitor paging.

[0072] The base station 104 receives (434) a message from the CN 110 including the paging subgroup configuration. Depending on implementation, the message may be a CN-to-BS message. The base station 104 may then perform an enhanced paging procedure using the paging subgroup configuration in paging procedure 496, similar to paging procedure 494, or may forgo using the paging subgroup configuration and perform a legacy paging procedure. Similar to event 494, the base station 106 may perform the enhanced or legacy paging procedure 496 with the UE 102 in response to receiving a downlink data packet from the CN 110 instead of a CN-to-BS message, such as when the UE 102 operates in an idle state with the RRC connection suspended.

[0073] In some implementations, the UE 102 receives the paging subgroup configuration from the base station 106 during the registration procedure 491. The UE 102 may then retain the paging subgroup configuration after selecting (or reselecting) 422 a new cell.

[0074] 4B, scenario 400B is similar to 400A and similarly involves UE 102 selecting (or reselecting) a cell 124 and then using a paging subgroup configuration to determine whether to monitor for paging. However, unlike scenario 400A, UE 102 performs an additional registration procedure with CN 110 to complete mobility and further bases the determination on whether the UE receives a paging subgroup configuration in cell 124.

[0075] After selecting (or reselecting) the cell 124, the UE 102 performs a registration procedure 492 with the base station 104, similar to the registration procedure 491 described in FIG. 4A above. The cells 124 and 126 may not belong to the same tracking area, unlike the scenario in FIG. 4A . The UE 102 may determine from the system information 402 and 424 that the cells 124 and 126 belong to different tracking areas. After completing the registration procedure 492, the UE 102 determines (426) whether the UE 102 received a paging subgroup configuration as part of the registration procedure 492. The UE 102 then determines (428) whether to use (430) or refrain from using (432) the paging subgroup configuration based at least in part on whether the cell 124 of the base station 104 supports paging subgrouping.

[0076] 5, in a scenario 500, the CN 110 communicates with the UE 102 via the base station 104 and provides the paging subgroup configuration to the UE 102 before the UE 102 transitions to an inactive state (e.g., RRC_INACTIVE) and begins monitoring for paging. FIG. 5 is similar to FIGS. 3, 4A, and 4B, except that the UE transitions to an inactive state instead of an idle state.

[0077] The UE 102 may receive system information in the cell 124 from the base station 104 (502), may perform a registration procedure (592), and may operate in a connected state (e.g., RRC_CONNECTED) within the cell 124 (504). The UE 102 may communicate data with the CN 110 via the base station 104 (505) until the base station 104 sends an RRC release message to the UE 102 (518). The base station 104 may send the RRC release message to the UE 102 (518) in response to detecting data inactivity of the UE 102. Prior to sending the RRC release message to the UE 102 (518), the base station 104 may receive a CN-to-BS message from the CN 110 (e.g., AMF 164) with a paging subgroup configuration for the UE 102 (517). For example, the message from the CN to the BS may be an NGAP message or an S1AP message. In another example, the message from the CN to the BS may be a Path Switch Request Acknowledge message, a Downlink NAS Transport message, a Handover Request message, a PDU Session Resources Setup Request message, a PDU Session Resources Modification Request message, or an Initial Context Setup Request message. In other scenarios, the base station 104 may receive a paging subgroup configuration from another base station other than the CN 110, for example, in a handover request message. The UE 102 then transitions to an inactive state (521). The procedure 590 for transitioning to an inactive state collectively includes events 592, 504, 505, 517, 518, and 521.

[0078] After the UE 102 begins operating in the inactive state 521, the UE 102 determines 528 whether the cell 124 supports paging subgrouping. If the UE 102 determines 528 that the cell 124 supports paging subgrouping, the UE 102 uses 530 the paging subgroup configuration to monitor paging. Otherwise, the UE 102 refrains from using 532 the paging subgroup configuration to monitor paging. The base station 104 may then determine to perform one of the enhanced or legacy paging procedures 596, as discussed in scenario 300 above (e.g., in response to receiving 533 a downlink data packet for the UE 102 from the CN 110). The downlink data packet may be a user plane data packet.

[0079] In this scenario, because the UE 102 did not transition to the RRC_IDLE state, the CN 110 can simply transmit a downlink data packet for the UE 102 (533) without sending a message from the CN to the BS with a paging subgroup configuration as in event 434 of scenarios 400A and 400B. In some implementations, the base station 104 may receive a tunnel packet from the CN 110 (e.g., the UPF 162) that includes the downlink data packet and a TEID that the base station 104 assigned for the UE 102. The base station 104 can determine from the TEID that the downlink data packet addresses the UE 102 and determine to page the UE 102 in response to the determination.

[0080] 6A , in scenario 600A, the UE 102 determines whether to use a paging subgroup configuration before the UE 102 selects (or reselects) a new cell 124 of the base station 104. After selecting the new cell 124, the UE 102 continues to operate in an inactive state. Similar to the scenario of FIG. 4A , the UE 102 determines whether to use paging subgrouping based on the system information of the cell 124 or whether the previous cell 126 and the new cell 124 belong to the same RNA, and can accordingly determine whether a previous decision regarding support for paging subgrouping in cell 126 also applies to cell 124.

[0081] The UE 102 may perform a procedure 690 to transition to an inactive state with the CN 110 via the base station 106 and may receive 602 system information about the cell 124 from the base station 104 before performing the procedure 690. In some implementations, the UE 102 and the base station 106 then perform an enhanced or legacy paging procedure 694 similar to the procedure 494 discussed above.

[0082] The UE 102 then selects (or reselects) 622 a new cell 124. In some implementations, after selecting the new cell 124, the UE 102 continues communicating in the same RNA. In some implementations, the UE 102 receives 624 system information from the base station 104. The UE 102 then determines 630 whether to use or refrain from using 632 a paging subgroup configuration to monitor paging. In some implementations, the UE 102 makes the determination based on 628 whether the cell 124 supports paging subgrouping, which in turn is based on whether the cells 124 and 126 belong to the same RNA. In other implementations, the UE 102 makes 628 the determination based on the system information the UE 102 received in event 624. If the base station 106 and the base station 104 are within the same RNA, the base station 106 transmits 646 the paging subgroup configuration to the base station 104. In some implementations, the base station 106 transmits 646 the configuration via a BS-to-BS paging message. In some implementations, the base station 106 receives 635 downlink data from the CN 110, similar to event 533. In some implementations, the base station 106 transmits 639 / 641 the downlink data to the base station 104. In some implementations, the base station 106 determines that the UE 102 does not successfully receive a page 639 / 641 after a predetermined period of time has elapsed without receiving an indication (e.g., an RRC resume request message) from the UE 102. In response to or after receiving 646 the BS-to-BS paging message or downlink data, the base station 104 determines to perform one of an enhanced or legacy paging procedure 696, as discussed in scenario 300 above.

[0083] Referring now to FIG. 6B, scenario 600B is similar to scenario 600A, except that UE 102 and base station 104 perform a registration procedure (692), and UE 102 determines whether to monitor paging using a paging subgroup configuration based further on whether UE 102 received a configuration during registration procedure 692 that the UE performs for mobility from base station 106 to base station 104.

[0084] Referring now to FIG. 6C, scenario 600C is generally similar to 600A, except that UE 102 performs a resumption procedure with base station 104 after transitioning to an inactive state (e.g., RRC_INACTIVE), and base station 104 retrieves the paging subgroup configuration for UE 102 from base station 106 during or in response to the resumption procedure.

[0085] In particular, after selecting (or reselecting) (622) the new cell 124, the UE 102 sends (650) a resume request message (e.g., an RRCResumeRequest message) to the base station 104 to resume its radio connection with the RAN 105 or to perform an RNA update. In some implementations, the cells 124 and 126 are in the same RNA. In other implementations, the cell 124 is in a new RNA compared to the cell 126. The base station 104 then sends (652) a request (e.g., a Retrieve UE Context Request message) to the base station 106 to retrieve the UE context for the UE 102. The base station 106 sends (654) a UE context response (e.g., a Retrieve UE Context Response message) to the base station 104 that includes the paging subgroup configuration. After receiving the configuration, the base station 104 may send (658) a resume message (e.g., an RRCResume message) to the UE 102 in response to the resume request message. In response to receiving 658 the resume message, the UE 102 begins operating 660 in a connected state (e.g., RRC_CONNECTED) and sends 662 a resume complete message (e.g., an RRCResumeComplete message) to the base station 104. After sending 654 the paging subgroup configuration to the base station 104, the base station 106 may release 656 the configuration.

[0086] Then, after receiving (662) the resume complete message from the UE 102, the base station 104 sends (664) an RRC release message to the UE 102 with an indication to suspend the radio resources, causing (621) the UE 102 to operate in an inactive state. The resume procedure 686 collectively includes steps 650, 652, 654, 656, 658, 660, 662, 664, and 621.

[0087] After performing the resume procedure 686, the base station 104 may transmit (647) a paging subgroup configuration to the base station 106, similar to event 646, and the base station 106 may attempt (639 / 641) to page the UE 102. In some implementations, the base station 104 transmits the configuration after deciding to do so based on downlink data received (633) from the CN 110. Similarly, the base station 106 may stop attempting to page the UE 102 after failing to transmit (639 / 641) the paging DCI and / or paging message. The base station 104 may identify from the TEID that the downlink data packet addresses the UE 102, similar to event 533. In response to the identification, the base station 104 may decide to page (696) the UE 102 and transmit (647) the configuration to the base station 106.

[0088] 7A, the UE 102 in scenario 700A establishes an emergency PDU session and refrains from using a paging subgroup configuration until the emergency PDU session is released. Because there are generally fewer paging occasions associated with a paging subgroup compared to a paging group, the UE 102 can prioritize speed over power savings by forgoing the paging subgroup configuration, even when the serving base station supports this paging enhancement. Similarly, the base station 104 refrains from using the paging subgroup configuration. However, after the UE 102 releases the emergency PDU session, the UE 102 can use the configuration to monitor paging.

[0089] 7A, the UE 102 performs a procedure 790 to transition to an inactive state similar to procedures 590 and 690 discussed above. The base station 106 can perform an enhanced or legacy paging procedure 794 with the UE 102 in response to a downlink data packet for the UE 102 from the CN 110 (event 703), similar to event 533. The UE 102 then establishes an emergency PDU session with the CN 110 (782).

[0090] After the UE 102 establishes (782) the emergency PDU session, the base station 104 sends (718) an RRC release message to the UE 102, similar to event 518. If the UE 102 operating in a connected state receives (718) the RRC release message, the UE 102 transitions (721) to an inactive state. If the UE 102 operating in an inactive state receives (718) the RRC release message, the UE 102 remains in the inactive state. Before the base station 104 sends the RRC release message or during establishment of the emergency PDU session, the CN 110 may send (727) a CN-to-BS message (e.g., a Downlink NAS Transport message, a PDU Session Resources Setup Request message, or a PDU Session Resources Modification Request message) to the base station 104. In some implementations, the CN 110 refrains from including a paging subgroup configuration in the CN-to-BS message (727). Accordingly, the base station 104 refrains from using the configuration (763) in response to receiving 727 the CN-to-BS message. In other implementations, the CN 110 includes a flag or field in the CN-to-BS message to explicitly indicate to the base station 104 that the base station 104 should not use any paging subgroup configuration that the base station 104 may have stored for the UE 102. Accordingly, the base station 104 refrains from using the configuration (763) in response to receiving 727 the flag or field. In other implementations, the base station 104 determines that the UE 102 has established an emergency PDU session (782) and refrains from using the paging subgroup configuration (763), regardless of whether the CN 110 provides such a flag or field. The base station 104 may determine that the UE 102 has established (782) an emergency PDU session based on a message from the CN to the BS that includes at least one of (i) an ID of the PDU session, (ii) QoS parameters associated with the PDU session, or (iii) an ID of a QoS flow associated with the PDU session.

[0091] In some implementations (not shown), the UE 102 in an inactive state performs a procedure to resume its radio connection with the base station 104 to establish (782) an emergency PDU session. To perform this procedure (782), the UE 102 transmits an RRC Resume Request message to the base station 104, the RRC Resume Request message including an emergency cause value. In response to the RRC Resume Request message, the base station 104 transmits an RRC Resume message to the UE 102. In response to the RRC Resume message, the UE 102 transitions to a Connected state and transmits an RRC Resume Complete message. To perform (782) the emergency PDU establishment procedure, the UE 102 in the Connected state transmits a PDU Session Establishment Request message to the CN 110 via the base station 104. In response, the CN 110 transmits a PDU Session Establishment Accept message to the UE 102 via the base station 104.

[0092] After establishing 782 the emergency PDU session, the inactive UE 102 refrains from using the paging subgroup configuration to monitor paging 732. In some implementations, during the emergency PDU session, the UE 102 and the base station 104 perform legacy paging procedures 799 for paging rather than enhanced paging procedures.

[0093] Eventually, the UE 102 may release the emergency PDU session with the CN 110 (784). The UE 102 may perform an emergency PDU session release procedure with the CN 110 to release the emergency PDU session (784). After releasing the emergency PDU session (784), the inactive UE 102 uses the paging subgroup configuration to monitor paging (730) and performs an enhanced paging procedure (798). In some implementations, the UE 102 performs a second procedure to resume its radio connection with the base station 104 to perform the emergency PDU session release procedure. In such implementations, the UE 102 transmits a second RRC resumption request message to the base station 104, the second RRC resumption request message including a non-emergency cause. In some implementations, the non-emergency cause may be mobile-originated signaling. The base station 104 may then transmit a second RRC resumption message in response to the second RRC resumption request message. In response to the second RRC resumption message, the UE 102 transitions to a connected state and sends a second RRC resumption complete message. To perform an emergency PDU session release procedure (784), the UE 102 in the connected state sends a PDU Session Release Request message to the CN 110 via the base station 104. In response, the CN 110 sends a PDU Session Release Command message to the UE 102 via the base station 104. In response to the PDU Session Release Command message, the UE 102 may send a PDU Session Release Complete message to the CN 110 via the base station 104. After completing the second resumption procedure or the emergency PDU session release procedure, the base station 104 may send an RRC release message to the UE 102 to transition the UE 102 to an inactive state (740).

[0094] After the UE 102 releases the emergency PDU session (784), or while the UE 102 is releasing the emergency PDU session (784), the CN 110 may send a CN-to-BS message (e.g., a Downlink NAS Transport message, a PDU Session Resources Release Command message, or an Initial Context Setup Request message) to the base station 104 (729). In some implementations, the CN 110 may indicate to the base station 104 to use a paging subgroup configuration (i.e., a first paging subgroup configuration) in the CN-to-BS message 729. For example, the CN 110 may include in the CN-to-BS message a paging subgroup configuration, or a field or IE to indicate to the base station 104 that a paging subgroup configuration is to be used. Thus, the base station 104 pages the UE 102 using the paging subgroup configuration in response to receiving the CN-to-BS message 729.

[0095] After receiving the indication, the base station 104 receives (735) downlink data packets for the UE 102 and performs (798) an enhanced paging procedure with the UE 102 using the paging subgroup configuration. After the inactive UE 102 releases (784) the emergency PDU session, it uses (730) the first paging subgroup configuration to monitor paging. In other implementations, the base station 104 determines (784) that the UE 102 releases (784) the emergency PDU session regardless of whether the CN 110 provides such an indication that it uses a paging subgroup configuration. The base station 104 may determine (784) that the UE 102 releases (784) the emergency PDU session based on (i) the ID of the PDU session, (ii) the QoS parameters associated with the PDU session, or (iii) the ID of the QoS flow associated with the PDU session in the CN-to-BS message 729. In response to the determination, the base station 104 pages the UE 102 using the paging subgroup configuration. After determining that the UE 102 releases the emergency PDU session, the base station 104 receives (735) downlink data packets for the UE 102 and performs (798) an enhanced paging procedure with the UE 102 using the paging subgroup configuration. After the UE 102 releases (784) the emergency PDU session, the inactive UE 102 uses (730) the first paging subgroup configuration to monitor paging.

[0096] In yet other implementations, the CN 110 includes the second paging subgroup configuration in the CN-to-BS message of event 729. The base station 104 then uses the second paging subgroup configuration to page the UE 102. In such a case, upon receiving (735) downlink data packets for the UE 102, the base station 104 performs (798) the enhanced paging procedure with the UE 102 using the second paging subgroup configuration. Depending on the implementation, the second paging subgroup configuration may be different or the same as the first paging subgroup configuration.

[0097] In some implementations, the CN 110 transmits a NAS message including the second paging subgroup configuration for the UE 102 during or after the emergency PDU session release procedure 784. In further implementations, the base station 104 transmits the second paging subgroup configuration to the UE 102 while transmitting the release command (740). Upon receiving the NAS message, the UE 102 in an inactive state uses the second paging subgroup configuration to monitor paging (730).

[0098] In some implementations, the UE 102 in the inactive state moves from the base station 104 to a new base station (e.g., base station 106) after releasing (784) the emergency PDU session. In some implementations, the base stations 104 and 106 belong to the same RNA. Therefore, the UE 102 in the inactive state avoids performing a resumption procedure similar to 686 in FIG. 6C . Upon receiving (733) the downlink data packet, the base station 104 determines to send a BS-to-BS paging message to page the UE 102 operating in the inactive state. In such implementations, the base station 104 determines not to include a paging subgroup configuration in the BS-to-BS paging message due to the emergency PDU session. In response to the determination, the base station 104 generates a BS-to-BS paging message that does not include a paging subgroup configuration and transmits the BS-to-BS paging message to the base station 106. Thus, the base station 106 uses legacy paging procedures to page the UE after or in response to receiving a BS-to-BS paging message that does not include a paging subgroup configuration.

[0099] In some implementations, the base station 104 can include an indication to the UE 102 to transition to the idle state in the RRC release message 718 / 740, and the UE 102 transitions to the idle state in response to the RRC release message. The idle UE 102 can perform an RRC connection procedure to release (784) the emergency PDU session. The UE 102 operating in the idle state with the emergency PDU session refrains from using (732) the paging subgroup configuration and performs (799) the legacy paging procedure. The UE 102 operating in the idle state without the emergency PDU session can use (730) the paging subgroup configuration and performs (798) the enhanced paging procedure. The example implementations described above may apply to the UE 102 operating in the idle state.

[0100] 7B, scenario 700B is generally similar to scenario 700A, except that here, the RAN 105 and the UE 102 release the paging subgroup configuration in response to the establishment of an emergency PDU session by the UE 102.

[0101] After the UE 102 establishes (782) the emergency PDU session, or while the UE 102 establishes (782) the emergency PDU session, the CN 110 may send (727) an indication to the base station 104 to release (753) the paging subgroup configuration. In some implementations, the CN 110 may send the indication by sending (727) a CN-to-BS message to the base station 104. In other implementations, the base station 104 instead determines that the UE 102 has an emergency PDU session according to information related to the PDU session, as described in scenario 700A above. At that time, the base station 104 releases the paging subgroup configuration. The UE 102 also releases (752) the paging subgroup configuration after or in response to the establishment (782) of the emergency PDU session.

[0102] Eventually, the UE 102 may release the emergency PDU session (784). After the UE 102 releases 784 the session, or in response to the release 784, the CN 110 may send a CN-to-BS message to the base station 104 (754). In some implementations, the CN-to-BS message includes a downlink NAS message. The downlink NAS message may include a second paging subgroup configuration. The base station 104 may send a downlink NAS message including the second paging subgroup configuration to the UE 102 (756). Depending on the implementation, the second paging subgroup configuration may be the same as or different from the first paging subgroup configuration. In a further implementation, the CN 110 sends a second CN-to-BS message including the second paging subgroup configuration to the base station 104 (731). In some implementations, the CN to BS message 754 may instead include the second paging subgroup configuration for the base station 104, and the CN to BS message 731 may be omitted. In some implementations, the second paging subgroup configuration may be different or the same as the first paging subgroup configuration. After sending the DL NAS message, the base station 104 may send 740 an RRC release message to the UE 102 to transition the UE 102 to an inactive or idle state.

[0103] 7C, scenario 700C is also generally similar to scenario 700A, except that in this scenario, UE 102 also selects (or reselects) a new cell 126 while the emergency PDU session is active.

[0104] After establishing 782 the emergency PDU session, the UE 102 may select (or reselect) 722 a new cell 126. In some implementations, the UE 102 performs the selection (or reselection) due to a change in location. Thus, the UE 102 performs a resumption procedure 786 with the base station 104 and the base station 106, as described in scenarios 500 and 600C above. After performing the resumption procedure 786, the base station 106 refrains from using 788 the paging subgroup configuration to page the UE 102. In some implementations, the base station 106 refrains from using 788 the paging subgroup configuration in response to the base station 104 sending an indication to suspend application of the configuration to the base station 106 during the resumption procedure 786. For example, the base station may include the indication in a Retrieve UE Context Response message during the resumption procedure 786. In other implementations, the base station 106 refrains from using the configuration (788) in response to the inclusion of information related to the emergency PDU session in the base station 104's transmission to the base station 106 during the resume procedure 786. In such implementations, the base station 106 may determine (782) that the UE 102 has established an emergency PDU session based on the information. For example, the information may include (i) an ID of the emergency PDU session, (ii) QoS parameters associated with the emergency PDU session, or (iii) an ID of a QoS flow associated with the emergency PDU session. In yet other implementations, the base station 104 refrains from sending the paging subgroup configuration to the base station 106 in the resume procedure. For example, the base station 104 may refrain from including the paging subgroup configuration in a Retrieve UE Context Response message.

[0105] 7D, scenario 700D is generally similar to scenario 700A, except that here, UE 102 retains the paging subgroup configuration for use after the emergency session ends when base station 104 releases the configuration and receives a configuration from CN 110.

[0106] After the UE 102 establishes (782) the emergency PDU session, the CN 110 sends (729) a UE context release message (e.g., a UE Context Release Command message) to the base station 104. In response to receiving (729) the UE context release message, the base station 104 releases (756) the paging subgroup configuration. However, after establishing (782) the emergency PDU session, the UE 102 retains (732) the paging subgroup configuration and refrains from using the configuration to monitor paging. After releasing (756) the configuration, the base station 104 sends (718) an RRC release message to the UE 102 to release radio resources and transition the UE 102 to an idle state. In response to the RRC release message, the UE 102 releases (720) the radio resources, retains the paging subgroup configuration, and begins operating (720) in the idle state. In some implementations, the UE 102 refrains from using the paging subgroup configuration after initiating idle operation 720 (732). The CN 110 sends a CN-to-BS message (e.g., an S1AP paging message or an NGAP paging message) to the base station 104 to page the UE 102 (734). In some implementations, the CN 110 may send the message (734) while the emergency session is ongoing and exclude the paging subgroup configuration. In response to or after receiving the CN-to-BS message, the base station 104 performs a legacy paging procedure with the UE 102 (799), as described above. The CN 110 may send a second CN-to-BS message (e.g., an S1AP paging message or an NGAP paging message) including the paging subgroup configuration to page the UE 102 after the UE 102 releases the emergency session (784) (731). In response to or after receiving the message from the second CN to the BS, the base station 104 performs (798) an enhanced paging procedure with the UE 102 as described above.

[0107] Several example methods that may be implemented in a UE, RAN, CU, or CN will now be discussed with reference to Figures 8-20. Each of these methods may be implemented using processing hardware, such as one or more processors, to execute instructions stored on a non-transitory computer-readable medium, such as a computer memory.

[0108] 8, a method 800 may be implemented in a suitable UE and includes determining whether to monitor for paging using a paging subgroup configuration based on support for paging subgrouping from a first cell and a second cell. For clarity, method 800 will be discussed with particular reference to cell 124, cell 126, and UE 102.

[0109] At block 802, the UE 102 receives a paging subgroup configuration via the first cell 126 (e.g., events 312, 491, 505, 690, and 790 of FIGS. 3-7D). At block 804, the UE 102 determines whether the first cell 126 supports paging subgrouping (e.g., events 328, 428, 528, and 628 of FIGS. 3-6C). If the cell 126 supports paging subgrouping, flow proceeds to block 806, where the UE 102 monitors paging via the cell 126 in accordance with the configuration (e.g., events 330, 430, 530, 630, and 730 of FIGS. 3-7D). If the cell 126 does not support paging subgrouping, the flow proceeds to block 808, where the UE 102 monitors for paging via the cell 126 without using the configuration (e.g., events 332, 432, 532, 632, 732, and 752 in Figures 3-7D).

[0110] At block 810, the UE 102 selects (or reselects) a new cell 124 (422, 622, and 722 in FIGS. 4A-4B, 6A-6D, and 7C). At block 812, the UE 102 determines whether the new cell 124 supports paging subgrouping (e.g., events 428 and 628 in FIGS. 4A-4B and 6A-6D). As discussed above, the determination may be based on, for example, whether the previous cell and the cell belong to the same RNA or a configuration the UE receives regarding the new cell. If the cell 124 supports paging subgrouping, flow continues to block 814, where the UE 102 monitors paging via the cell 124 according to the configuration (e.g., events 430 and 630 in FIGS. 4A-4B and 6A-6D). If the cell 124 does not support paging subgrouping, the flow continues to block 816, where the UE 102 monitors for paging via the cell 124 without using the configuration (e.g., events 432 and 632 in Figures 4A-4B and 6A-6D).

[0111] 9A, a method 900A may be implemented in a suitable UE and includes determining whether to indicate support for paging subgrouping in an uplink message based on whether the UE enables support for paging subgrouping for a public land mobile network (PLMN) of a cell. For clarity, the method 900A will be discussed specifically with reference to the UE 102 and the cell 124.

[0112] At block 902, the UE 102 selects (or reselects) a cell 124 (e.g., events 422 and 622 in FIGS. 4A-4B and 6A-6C). At block 904, the UE 102 determines to transmit an uplink message via the cell 124 (e.g., events 492 and 650 / 692 in FIGS. 4B and 6B-6C). In some implementations, the uplink message is an uplink NAS message, and the UE 102 transmits the uplink NAS message to the CN via the cell 124. In some implementations, the uplink NAS message is a registration request message. In other implementations, the uplink message is an uplink RRC message, and the UE 102 transmits the uplink RRC message to the RAN via the cell. In some implementations, the uplink RRC message is a UE capability information message.

[0113] At block 906, the UE 102 determines whether the UE 102 enables support for paging subgrouping for the PLMN of the cell 124. In some implementations, the UE 102 stores different configurations for different network operators. In one implementation, the UE 102 may determine to use the configuration for the network operator of the cell 124. In another implementation, the UE 102 may determine to use the configuration for the network operator of the USIM in the UE 102. If the UE 102 uses the configuration for a network operator that supports paging subgrouping, the UE 102 may determine that the UE 102 enables support for paging subgrouping. If the UE 102 enables support, flow continues to block 908, where the UE 102 indicates support for paging subgrouping in an uplink message. If the UE 102 does not enable support, flow continues to block 910, where the UE 102 refrains from indicating support for paging subgrouping in the uplink message. The UE 102 then transmits the uplink message via the cell 124 in block 912 (e.g., events 492 and 650 / 692 in FIGS. 4B and 6B-6C).

[0114] 9B, method 900B is generally similar to method 900A, except that here the UE determines whether to indicate support based on whether the cell supports paging subgrouping. More specifically, the differences between the methods of FIG. 9A and FIG. 9B are discussed below.

[0115] After the UE 102 determines in block 904 to transmit an uplink message via the cell 124, the UE 102 determines in block 907 whether the cell 124 supports paging subgrouping. If the cell 124 does support paging subgrouping, flow continues to blocks 908 and 912 described in the method 900A above (e.g., events 492 and 650 / 692 in FIGS. 4B and 6B-6C). If the cell does not support paging subgrouping, flow continues to blocks 910 and 912 described in the method 900A above (e.g., events 492 and 650 / 692 in FIGS. 4B and 6B-6C).

[0116] 10, a method 1000 may be implemented in a suitable UE and includes obtaining a first configuration and a second configuration of paging subgroups from a CN via a first cell and a second cell, respectively, belonging to a PLMN. For clarity, the method 1000 will be discussed with particular reference to the UE 102 and the CN 110.

[0117] In block 1002, the UE 102 sends a first uplink NAS message to the CN 110 via a first cell belonging to a first tracking area (TA) of the PLMN to request configuration of paging subgroups (e.g., events 306, 491, 592, 690, and 790 in FIGS. 3-7D ). In some implementations, the flow continues to block 1004, where the UE 102 receives a first downlink NAS message from the CN 110, the message including a first configuration of paging subgroups via the first cell (e.g., events 312, 491, 592, 690, and 790 in FIGS. 3-7D ). In some implementations, the UE 102 includes an indication in the first uplink NAS message to indicate support for paging subgroups.

[0118] In block 1006, the UE 102 then selects (or reselects) a second cell belonging to a second TA of the PLMN (e.g., events 422 and 622 in FIGS. 4A-4B and 6A-6C). In block 1008, the UE 102 transmits a second uplink NAS message to the CN 110 via the second cell to request configuration of paging subgroups (e.g., events 492 and 692 / 650 in FIGS. 4B and 6B-6C). In some implementations, the UE 102 indicates support for paging subgroups through the configuration request. In a further implementation, flow continues to block 1010, where the UE 102 receives a second downlink NAS message from the CN 110 via the second cell, the message including a second configuration of paging subgroups (e.g., events 492 and 692 / 650 in FIGS. 4B and 6B-6C). In some implementations, the UE 102 includes an indication to indicate support for paging subgrouping in the uplink NAS message. In some implementations, the UE 102 determines whether to continue to enable support for paging subgrouping after selecting (or reselecting) the second cell in block 1006. If the UE 102 determines to continue to enable support, the UE 102 sends an indication of support in the second uplink NAS message in block 1008. If the UE 102 decides to stop enabling support, the UE 102 does not include an indication of support in the second uplink NAS message. In some implementations, the first configuration and the second configuration can be the same or different.

[0119] 11, a method 1100 may be implemented in a suitable UE and includes the UE determining whether to update or release a first configuration of paging subgroups with a second configuration of paging subgroups. For clarity, the method 1100 will be discussed with particular reference to the UE 102, the CN 110, and the RAN 105.

[0120] In block 1102, the UE 102 receives a first downlink NAS message from the CN 110 via the RAN 105, the message including a first configuration of paging subgroups (e.g., events 312, 491, 505, 690, and 790 in FIGS. 3-7D). In block 1104, the UE 102 receives a second downlink NAS message from the CN 110 via the RAN 105 after receiving the first configuration (e.g., events 492 and 692 in FIGS. 4B and 6B). In block 1106, the UE 102 determines whether the second downlink NAS message includes a second configuration of paging subgroups (e.g., events 426 and 626 in FIGS. 4B and 6B-6C). If the second downlink NAS message includes the second configuration, flow continues to block 1108, where the UE 102 updates the first configuration with the second configuration of the paging subgroup. If the second downlink NAS message does not include the second configuration, flow continues to block 1110, where the UE 102 releases the first configuration of the paging subgroup. In some implementations, the UE 102 instead retains the first configuration in block 1110. Depending on the implementation, the first configuration may be the same as the second configuration, or the two configurations may be different. In some implementations, the second downlink NAS message also does not include an explicit indication to the UE 102 to release the first configuration if the second downlink NAS message does not include the second configuration.

[0121] 12A, a method 1200A may be implemented in a preferred RAN and includes determining whether to page a UE according to a paging subgroup configuration based on whether a cell supports paging subgrouping. For clarity, the method 1200A will be discussed with particular reference to the UE 102, the CN 110, and the RAN 105.

[0122] In block 1202, the RAN 105 receives a paging subgroup configuration for the UE 102 from the CN 110 (e.g., events 310, 491, 505, 690, and 790 in FIGS. 3-7D ). In some implementations, the CN 110 transmits a downlink NAS message to the UE 102 via the RAN 105 simultaneously with or after the RAN 105 receives the configuration. Depending on the implementation, the configuration that the CN 110 transmits to the UE 102 may be the same as the configuration that the RAN 105 receives. In block 1204, the RAN 105 determines to page the UE 102 via the cell (e.g., events 336 / 337, 494 / 496, 596, 694 / 696, and 794 / 796 in FIGS. 3-7D ). In block 1206, the RAN 105 determines whether the cell supports paging subgrouping. If the cell does support paging subgrouping, flow continues to block 1208, where the RAN 105 pages the UE 102 via the cell according to the configuration (e.g., events 336, 494 / 496, 596, 694 / 696, and 794 / 796 in FIGS. 3-7D). If the cell does not support paging subgrouping, flow continues to block 1210, where the RAN 105 refrains from using the configuration to page the UE 102 (e.g., events 337, 494 / 496, 596, 694 / 696, and 794 / 796 in FIGS. 3-7D). In block 1212, the RAN 105 pages the UE 102 via the cell without using a paging subgroup configuration (e.g., events 342 / 344, 494 / 496, 596, 694 / 696, and 794 / 796 in Figures 3-7D).

[0123] 12B, method 1200B is generally similar to method 1200A, except that the RAN further determines whether the UE has established an emergency PDU session. More specifically, the differences between the methods of FIG. 12A and FIG. 12B are discussed below.

[0124] After the RAN 105 determines to page the UE 102 via the cell in block 1204, flow continues to block 1207, where the RAN 105 determines whether the UE 102 has an emergency PDU session (e.g., event 782 in FIGS. 7A-7D ). In some implementations, the RAN 105 determines whether the UE 102 has an emergency PDU session, as described in FIGS. 7A and 7B above. If the UE 102 does not have an emergency PDU session, flow continues to block 1208 described in method 1200A. If the UE 102 does have an emergency PDU session, flow continues to blocks 1210 and 1212 described in method 1200A (e.g., events 763 / 753 / 756 and 799 in FIGS. 7A-7D ).

[0125] 13A, a method 1300A may be implemented in a preferred CU and includes determining whether to include a paging subgroup configuration in a message from the CU to the DU based on whether the DU supports paging subgroup configuration. For clarity, the method 1300A will be discussed with particular reference to the DU 174, the CU 172, the CN 110, and the UE 102.

[0126] In block 1302, the CU 172 receives a paging subgroup configuration for the UE 102 from the CN 110 (e.g., events 310, 491, 505 / 517, 690, 790 in FIGS. 3-7D). In block 1304, the CU 172 determines whether the DU 174 supports paging subgroup configuration. If the DU 174 supports the configuration, flow continues to block 1306, where the CU 172 sends a CU-to-DU message to the DU 174 that includes the configuration. If the DU 174 does not support the configuration, flow continues to block 1308, where the CU 172 sends a CU-to-DU message to the DU 174 that does not include the configuration.

[0127] 13B, method 1300B is generally similar to method 1300A, except that the CU further determines whether the UE has established an emergency PDU session. More specifically, the differences between the methods of FIG. 13A and FIG. 13B are discussed below.

[0128] After receiving the paging subgroup configuration in block 1302, the CU 172 determines whether the UE 102 has an emergency PDU session in block 1305. If the UE 102 does not have an emergency PDU session, flow continues to block 1306 described in method 1300A. If the UE 102 does have an emergency PDU session, flow continues to block 1308 described in method 1300A. In some implementations, the CU 172 performs block 1304 described in method 1300A in addition to block 1305 and sends a CU-to-DU message including the configuration only if the UE 102 does not have an emergency session and the DU 174 supports the configuration.

[0129] 13C, method 1300C is generally similar to method 1300A, except that the CU further determines whether the CU supports paging subgroup configuration. More specifically, the differences between the methods of FIG. 13A and FIG. 13C are discussed below.

[0130] After receiving the paging subgroup configuration in block 1302, the CU 172 determines in block 1303 whether the CU 172 supports the configuration. If the CU 172 supports the configuration, flow continues to block 1306, described in method 1300A. If the CU 172 does not support the configuration, flow continues to block 1308, described in method 1300A. In some implementations, if the CU 172 does not support the configuration, the CU 172 sends the configuration to the CN 110. Depending on the implementation, the CU 172 may determine that it does not recognize the configuration and forward a message including all unrecognized data to the CN 110, or the CU 172 may determine that it recognizes the configuration but cannot support it and forward only the configuration to the CN 110. In some implementations, the CU 172 performs one or both of blocks 1304 and 1305 described in methods 1300A and 1300B in addition to block 1303. In some implementations, the CU 172 may send a CU-to-DU message containing a configuration only when the UE 102 does not have an emergency session, the DU 174 supports the configuration, and the CU 172 supports the configuration. In some implementations, the CU 172 may send a CU-to-DU message containing a configuration when some subset of the conditions of blocks 1303, 1304, and 1305 are met.

[0131] 14A, a method 1400A may be implemented in a preferred CN and includes determining whether to send a paging subgroup configuration to a base station based on whether the base station supports paging subgrouping. For clarity, the method 1400A will be discussed with particular reference to the CN 110, the RAN 105, the base station 104, and the UE 102.

[0132] In block 1402, the CN 110 sends a paging subgroup configuration to the UE 102 via the RAN 105 (e.g., events 310 / 310, 491, 505 / 517, 690, and 790 in FIGS. 3-7D). In block 1404, the CN 110 decides to send a CN-to-BS message for the UE 102 to the base station 104 of the RAN 105. In block 1406, the CN 110 determines whether the base station 104 supports paging subgroup configuration. If the CN 110 determines that the base station 104 supports the configuration, flow continues to block 1408, where the CN 110 includes the configuration in a CN-to-BS message. If the CN 110 determines that the base station 104 does not support the configuration, flow continues to block 1410, where the CN refrains from including the configuration in the CN-to-BS message. After either block 1408 or 1410, flow continues to block 1412, where the CN 110 sends a CN-to-BS message to the base station 104 (e.g., events 334, 434, 517, 690, and 797 / 727 / 729 / 754 / 731 / 734 in FIGS. 3-7D).

[0133] 14B, method 1400B is generally similar to method 1400A, except that the CN further determines whether the UE has established an emergency PDU session. More specifically, the differences between the methods of FIG. 14A and FIG. 14B are discussed below.

[0134] After the CN 110 determines in block 1404 to send a CN-to-BS message for the UE 102 to a base station 104 of the RAN 105, flow proceeds to block 1407, where the CN 110 determines whether the UE 102 has an emergency PDU session (e.g., event 782 in FIGS. 7A-7D ). If the UE 102 does not have an emergency PDU session, flow continues to blocks 1408 and 1412 described in method 1400A (e.g., events 797, 727, 729, 754, 731, or 734 in FIGS. 7A-7D ). If the UE 102 has an emergency PDU session, flow continues to blocks 1410 and 1412 described in method 1400A (e.g., events 797, 727, 729, 754, 731, or 734 in FIGS. 7A-7D ).

[0135] 15, a method 1500 may be implemented in a preferred CN and includes determining whether to send a second configuration of paging subgroups to the UE via the RAN based on whether a registration request from the UE indicates support for paging subgrouping. For clarity, the method 1500 will be discussed with particular reference to the CN 110, the RAN 105, and the UE 102.

[0136] In block 1502, the CN 110 performs an initial registration procedure with the UE 102 via the RAN 105 (e.g., events 392, 491, 505, 690 / 686, and 790 in FIGS. 3-7D). In block 1504, the CN 110 transmits a first configuration of paging subgroups to the UE 102 (e.g., events 310 / 312, 491, 505, 690, and 790 in FIGS. 3-7D). In some implementations, the CN 110 transmits the configuration during the initial registration procedure. In other implementations, the CN 110 transmits the configuration after the initial registration procedure is completed. In block 1506, the CN 110 receives a subsequent registration request from the UE 102 via the RAN 105 (e.g., events 492 and 692 in FIGS. 4B and 6B). The CN 110 then determines, in block 1508, whether a message from the UE 102 containing a subsequent registration request further includes an indication of support for paging subgrouping. If the message includes an indication of support, flow continues to block 1510, where the CN 110 includes a second configuration of paging subgroups in a subsequent registration accept message (e.g., events 492 and 692 in FIGS. 4B and 6B). If the message does not include an indication of support, flow continues to block 1512, where the CN 110 refrains from including the configuration in a subsequent registration accept message (e.g., events 492 and 692 in FIGS. 4B and 6B). In some implementations, the CN 110 releases the first paging subgroup configuration if the message does not include an indication of support. After either block 1510 or 1512, flow continues to block 1514, where the CN 110 sends a subsequent registration accept message to the UE 102 via the RAN 105 (e.g., events 492 and 692 in FIGS. 4B and 6B). In some implementations, the first configuration of paging subgroups and the second configuration of paging subgroups may be the same or different.In a further implementation, the UE 102 updates the first configuration with the second configuration.

[0137] 16, a method 1600 may be implemented in a preferred CN and includes suspending and then resuming application of a paging subgroup configuration. For clarity, the method 1600 will be discussed with particular reference to the CN 110, the UE 102, and the RAN 105.

[0138] In block 1602, the CN 110 sends a first downlink NAS message to the UE 102 via the RAN 105, the message including the paging subgroup configuration (e.g., events 310 / 312, 491, 505 / 517, 690, and 790 in FIGS. 3-7D). In block 1604, the CN 110 then sends a first CN-to-BS message to the RAN 105, the CN-to-BS message including the configuration (e.g., events 334, 434, 517, 690, and 797 / 727 / 729 / 754 / 731 / 734 in FIGS. 3-7D). In block 1606, the CN 110 decides to suspend application of the paging subgroup configuration. In block 1608, the CN 110 sends a second CN-to-BS message to the RAN 105 to configure the RAN 105 to suspend application of the configuration (e.g., events 727 / 729 in FIGS. 7A-7D ). In some implementations, the CN 110 decides to configure the RAN to suspend application of the configuration in response to an event known between the UE 102 and the CN 110. In such implementations, the CN 110 may not send a downlink NAS message to configure the UE to suspend application of the configuration. Instead, the UE 102 may suspend application of the configuration and monitor paging without using the configuration. In some implementations, the event known to the UE 102 and the CN 110 is the UE 102 establishing an emergency PDU session with the CN 110.

[0139] In block 1610, the CN 110 may decide to resume application of the paging subgroup configuration. In block 1612, the CN 110 may send a third CN-to-BS message to resume application of the configuration (e.g., events 729, 731, 734, or 754 in FIGS. 7A-7D). In some implementations, the CN 110 sends the third CN-to-BS message after an event known to the UE 102 and the CN 110 ends.

[0140] 17, a method 1700 may be implemented in a preferred CN and includes determining to release a paging subgroup configuration and then sending a command to the UE to release the paging subgroup configuration. For clarity, the method 1700 will be discussed with particular reference to the CN 110, the UE 102, and the RAN 105.

[0141] In block 1702, the CN 110 sends a first downlink NAS message to the UE 102 via the RAN 105, the message including a paging subgroup configuration (e.g., events 310 / 312, 491, 505 / 517, 690, and 790 in FIGS. 3-7D). In block 1704, the CN 110 sends a first CN-to-BS message including the configuration to the RAN 105 (e.g., events 334, 434, 517, 690, and 797 / 727 / 729 / 754 / 731 / 734 in FIGS. 3-7D). In block 1706, the CN 110 decides to release the configuration. In some implementations, the CN 110 decides to release the configuration in response to an event known between the UE 102 and the CN 110. Depending on the implementation, the event may be the UE 102 establishing an emergency PDU session with the CN 110 .

[0142] In block 1708, the CN 110 sends a second CN-to-BS message to the RAN 105 to release the paging subgroup configuration. In block 1710, the CN 110 may send a second downlink NAS message to the UE 102 via the RAN 105 to release the configuration (e.g., events 727 / 729 in FIGS. 7A-7D ). In such implementations, the UE 102 releases the configuration in response to the event, as described above. In some implementations, the CN 110 refrains from sending a downlink NAS message to release the paging subgroup configuration. In such implementations, the UE 102 refrains from using the configuration in response to the event, as described above.

[0143] Referring now to FIG. 18, method 1800 is a method in UE 102 or another suitable UE for managing paging subgrouping.

[0144] In block 1802, the UE 102 receives a paging subgroup configuration from the RAN 105 (e.g., events 312, 491, 505, 690, 790, 802, 1004, 1102, 1402, 1504, 1602, and 1702 of FIGS. 3-8, 10-11, and 14-17). In block 1804, the UE 102 determines whether the UE 102 should use the configuration to monitor paging in the cell based on at least whether the cell supports paging subgrouping (e.g., events 328 / 330 / 332, 428 / 430 / 432, 528 / 530 / 532, 628 / 630 / 632, 794, 804, and 907 of FIGS. 3-8 and 9B). In block 1806, the UE 102 monitors paging in the cell according to the determination (eg, events 330 / 332, 430 / 432, 530 / 532, 630 / 632, 794, and 806 / 808 in FIGS. 3-8).

[0145] Referring now to FIG. 19, method 1900 is a method in RAN 105 or another suitable RAN for managing paging subgrouping.

[0146] In block 1902, the RAN 105 receives from the core network a configuration of paging subgroups for the UE 102 (e.g., events 310, 491, 505 / 517, 690, 790, 802, 1102, 1202, 1302, 1402, 1504, 1602, and 1702 in FIGS. 3-8 and 11-17). In block 1904, the RAN 105 determines that the cell in which the UE 102 operates supports paging subgrouping (e.g., events 328, 428, 528, 628, and 1206 in FIGS. 3-6C and 12A). In block 1906, the RAN 105 pages the UE 102 according to the configuration in response to determining that the cell in which the UE 102 operates supports paging subgrouping (e.g., events 336 / 338 / 340, 496, 596, 696, 798, and 1208 of Figures 3-7D and 12A).

[0147] Referring now to FIG. 20, method 2000 is a method in CN 110 or another suitable CN for managing paging subgrouping.

[0148] In block 2002, the CN 110 transmits the paging subgroup configuration to the UE 102 via the RAN 105 (e.g., events 310 / 312, 491, 505 / 517, 690, 790, 802, 1102, 1202, 1302, 1402, 1504, 1602, and 1702 of FIGS. 3-8 and 11-17). In block 2004, the CN 110 then determines whether a message associated with the UE 102, destined for the base station 104 in the RAN 105, should include the configuration (e.g., event 1406 of FIG. 14A), based at least in part on whether the base station 104 supports paging subgrouping. In block 2006, the CN 110 then transmits a message to the base station 104 that is destined for the base station 104 and that is related to the UE 102 (eg, event 1412 in FIG. 14A).

[0149] The following list of examples reflects various embodiments expressly contemplated by this disclosure.

[0150] Example 1. A method for managing paging subgrouping implemented in a user equipment (UE) operating within a cell of a radio access network (RAN), the method comprising: receiving, by processing hardware, a configuration of paging subgroups from the RAN; determining, by the processing hardware, whether the UE should use the configuration to monitor paging in the cell based on at least whether the cell supports paging subgrouping; and monitoring, by the processing hardware, paging in the cell in accordance with the determination.

[0151] Example 2. The method of Example 1, further comprising receiving, by processing hardware, system information from the RAN, the system information including an indication that the cell supports paging subgrouping.

[0152] Example 3. The method of Example 1 further comprising receiving, by the processing hardware, from the RAN, a message associated with a protocol for controlling radio resources, the message (i) indicating that the UE should transition to an idle or inactive state associated with the protocol, and (ii) including a list of cells that support paging subgrouping.

[0153] Example 4. The method of Example 1, further comprising determining, by the processing hardware, in response to receiving the configuration, that the cell supports paging subgrouping.

[0154] Example 5. The method of example 4 including receiving the configuration in a registration acceptance message.

[0155] Example 6. The method of any of Examples 1 to 5, further comprising the steps of selecting or reselecting a new cell after determining that the cell supports paging subgrouping, and determining that the new cell supports paging subgrouping in response to determining that the cell and the new cell belong to the same RAN notification area.

[0156] Example 7. The method of any of Examples 1 to 5, further comprising the steps of selecting or reselecting a new cell after determining that the cell supports paging subgrouping, and receiving, by processing hardware, in the new cell, a new configuration of paging subgroups.

[0157] Example 8. The method of any of Examples 1 to 7, further comprising the step of sending, by the processing hardware to the RAN, a request for configuration to the cell, wherein receiving the configuration is responsive to the request.

[0158] Example 9. The method of Example 8, further comprising, after the monitoring step, selecting or reselecting a new cell, sending, by the processing hardware to the RAN, a request for configuring a paging subgroup to the new cell.

[0159] Example 10. The method of any of Examples 1 to 9, further comprising transmitting, by processing hardware to the RAN, an indication that the UE supports paging subgrouping.

[0160] Example 11. The method of example 10, wherein the step of transmitting the indication includes transmitting the indication in an uplink non-access stratum message.

[0161] Example 12. The method of example 11, wherein the non-access stratum message is a registration request.

[0162] Example 13. The method of example 10, wherein the step of transmitting the indication includes transmitting the indication in an uplink message associated with a protocol for controlling radio resources.

[0163] Example 14. The method of example 13, wherein the uplink message is a capability information message.

[0164] Example 15. The method of any of Examples 10 to 14, including sending an indication before transitioning from a connected state associated with a protocol for controlling radio resources to an idle or inactive state associated with the protocol.

[0165] Example 16. The method of any of Examples 10-14 including transmitting an indication in response to a cell selection or reselection.

[0166] Example 17. The method of any of Examples 10-16, including transmitting an indication in response to determining that the UE is configured to support paging subgrouping for a public land mobile network (PLMN) with which the cell is associated.

[0167] Example 18. The method of any of Examples 10-16, including transmitting an indication in response to determining that the cell supports paging subgrouping.

[0168] Example 19. The method of any of the preceding examples, wherein the monitoring step includes monitoring for paging in the cell in an idle state according to a configuration associated with a protocol for controlling radio resources.

[0169] Example 20. The method of any of the preceding examples, wherein the monitoring step includes monitoring paging in the cell according to a configuration in an inactive state associated with a protocol for controlling radio resources.

[0170] Example 21. The method of Example 1, further comprising determining, by the processing hardware, in response to determining that the UE has established an emergency PDU session, that the UE should refrain from using the configuration to monitor paging.

[0171] Example 22. The method of Example 21, further comprising determining, by processing hardware, in response to determining that the emergency PDU session is released, that the UE should use the configuration to monitor paging.

[0172] Example 23. The method of Example 1, further comprising, in response to determining that the UE has established an emergency PDU session, releasing the configuration by the processing hardware.

[0173] Example 24. The method of any of the above examples, further including, by the processing hardware, after the monitoring step, receiving a second configuration of the paging subgroups, and updating the configuration of the paging subgroups using the second configuration of the paging subgroups.

[0174] Example 25. User equipment (UE) including processing hardware and configured to perform a method according to any of Examples 1 to 24.

[0175] Example 26. A method for managing paging subgrouping for a UE, the method being implemented in a radio access network (RAN) and comprising: receiving, by processing hardware, a configuration of paging subgroups for the UE from a core network (CN); determining, by the processing hardware, that a cell in which the UE operates supports paging subgrouping; and, in response to the determination, paging, by the processing hardware, the UE in accordance with the configuration.

[0176] Example 27. The method of Example 26, wherein the determining step further includes determining that the UE is not currently engaged in an emergency PDU session.

[0177] Example 28. The method of Example 26, comprising receiving a configuration at a centralized unit (CU) of the distributed base station, and transmitting, by processing hardware, the configuration to a distributed unit (DU) of the distributed base station.

[0178] Example 29. The method of Example 28, including sending a configuration to the DU in response to determining that the UE is not currently engaged in an emergency PDU session.

[0179] Example 30. The method of either example 28 or 29, including sending a configuration to the DU in response to determining that the CU supports paging subgrouping.

[0180] Example 31. The method of any of Examples 26 to 30, further comprising transmitting, by processing hardware to the UE, system information including an indication that the cell supports paging subgrouping.

[0181] Example 32. The method of any of Examples 26 to 30, further comprising the step of transmitting, by processing hardware, to the UE, a message associated with a protocol for controlling radio resources, the message (i) indicating that the UE should transition to an idle or inactive state associated with the protocol, and (ii) including a list of cells that support paging subgrouping.

[0182] Example 33. The method of any of Examples 26 to 32, further comprising receiving, by the processing hardware, a request for a configuration for a cell from the UE, and transmitting, by the processing hardware to the UE, the configuration in response to the request.

[0183] Example 34. A radio access network (RAN) including one or more network nodes and configured to implement a method according to any of Examples 26 to 33.

[0184] Example 35. A method for managing paging subgrouping for a UE, the method being implemented in a core network (CN) and comprising: transmitting, by processing hardware, a paging subgroup configuration to a user equipment (UE) via a radio access network (RAN); determining, by the processing hardware, whether a message relevant to the UE, destined for a base station in the RAN, should include the configuration based at least in part on whether the base station supports paging subgrouping; and transmitting, by the processing hardware, the message relevant to the UE, destined for the base station, to the base station.

[0185] Example 36. The method of example 35, wherein the determining step includes refraining from including the configuration in the message in response to determining that the base station does not support paging subgrouping.

[0186] Example 37. The method of example 35, wherein the determining step includes including a configuration in the message in response to determining that the base station supports paging subgrouping.

[0187] Example 38. The method of example 35, wherein determining whether the message should include a configuration is further based on whether the UE is currently engaged in an emergency PDU session.

[0188] Example 39. The method of example 35, wherein the message is a message from the CN to the BS.

[0189] Example 40. A core network (CN) including processing hardware and configured to perform a method according to any of Examples 35 to 39.

[0190] The following explanation may apply to the above explanation.

[0191] In some implementations, "message" is used and may be replaced by "information element (IE)". In some implementations, "IE" is used and may be replaced by "field". In some implementations, "configuration" may be replaced by "configurations" or configuration parameters. In some implementations, "early data communication" may be replaced by "small data communication" and "early data transmission" may be replaced by "small data transmission".

[0192] When a cell is operated in a time division duplex (TDD) mode or on a TDD carrier frequency, the DL BWP and UL BWP (i.e., associated with the DL BWP) of the cell may be the same BWP. When a cell is operated in a frequency division duplex (FDD) mode or on a pair of FDD carrier frequencies (i.e., a UL carrier frequency and a DL carrier frequency), the DL BWP and UL BWP (i.e., associated with the DL BWP) of the cell may be different BWPs. In this case, the DL BWP is the BWP of the DL carrier frequency, and the UL BWP is the BWP of the UL carrier frequency. In some implementations, one of the UL BWPs of a cell may partially overlap with another UL BWP or not overlap at all with the other UL BWP. In other implementations, one of the UL BWPs may be completely within another UL BWP. In some implementations, one of the DL BWPs of a cell may partially overlap with another UL BWP or not overlap at all with the other UL BWP. In other implementations, one of the DL BWPs may be completely within another UL BWP.

[0193] A user device (e.g., UE 102) in which the techniques of this disclosure may be implemented can be any suitable device capable of wireless communication, such as a smartphone, tablet computer, laptop computer, mobile game console, point-of-sale (POS) terminal, health monitoring device, drone, camera, media streaming dongle or another personal media device, wearable device such as a smart watch, wireless hotspot, femtocell, or broadband router. Furthermore, in some cases, the user device may be integrated into an electronic system such as a vehicle head unit or an advanced driver assistance system (ADAS). Furthermore, the user device may operate as an Internet of Things (IoT) device or a mobile internet device (MID). Depending on the type, the user device may include one or more general-purpose processors, computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0194] Certain embodiments are described in this disclosure as including logic or several components or modules. The modules may be software modules (e.g., code or machine-readable instructions stored on a non-transitory machine-readable medium) or hardware modules. A hardware module is a tangible unit capable of performing specific operations and may be configured or arranged in a specific way. A hardware module may include dedicated circuitry or logic that is permanently configured to perform specific operations (e.g., as a field programmable gate array (FPGA) or application-specific integrated circuit (ASIC), dedicated processor such as a digital signal processor (DSP)) or the like. A hardware module may also include programmable logic or circuitry that is temporarily configured by software to perform specific operations (e.g., as contained within a general-purpose processor or other programmable processor). The decision to implement a hardware module in dedicated, permanently configured circuitry or temporarily configured circuitry (e.g., configured by software) may be driven by cost and time considerations.

[0195] When implemented in software, the techniques may be provided as part of an operating system, a library used by multiple applications, a specific software application, etc. The software may be executed by one or more general-purpose processors or one or more special-purpose processors. [Explanation of symbols]

[0196] 100 Wireless Communication System 101UE 103UE 102UE 104 Base station (BS) 104A base station 104B base station 105 RAN 106 Base Station 106A base station 106B base station 110 Core Network (CN) 111 Evolved Packet Core (EPC) 112 Serving Gateway (SGW) 114 Mobility Management Entity (MME) 116 Packet Data Network Gateway (PGW) 124 cells 126 cells 130 Processing Hardware 132 Component, Medium Access Control (MAC) Controller 134 Component, Packet Data Convergence Protocol (PDCP) Controller 136 Components, RRC Controller 138 Component, Paging Controller 142 Component, MAC Controller 144 Components, PDCP Controller 146 Components, RRC Controller 148 Component, Paging Controller 150 Processing Hardware 152 Medium Access Control (MAC) Controller 154 PDCP Controller 156 RRC Controller 158 Paging Controller 160 5th Generation (5G) Core (5GC) 162 User Plane Function (UPF) 164 Access and Mobility Management Function (AMF) 166 Session Management Facility (SMF) 172 Central Unit (CU) 172A CU-CP 172B CU-UP 174 DU 200 Protocol Stack 202A EUTRA Physical Layer (PHY) 202B NR PHY 204A EUTRA MAC Sublayer 204B NR MAC sublayer 206A EUTRA RLC Sublayer 206B NR RLC sublayer 208 EUTRA PDCP Sublayer 210 NR PDCP Sublayer 212 Service Data Adaptation Protocol (SDAP) 214 RRC 250 Wireless Protocol Stack 300 Scenarios 304 Events 306 Events 308 Events 310 Event, Registration Accept Message 312 Events 314 Events 316 Events 318 Events 328 Events 330 Events 332 Events 334 Events 336 Events 337 Events 338 Events 340 Events 342 Events 344 Events 392 Events, Registration Procedures 394 Events 396 Enhanced or Legacy Paging Procedures 398 Enhanced Paging Procedures 399 Legacy Paging Procedures 400A Scenario 400B Scenario 422 Events 426 Events 428 Events 430 Events 432 Events 434 Events 491 Events, Registration Procedures 492 Events, Registration Procedures 494 Events, Enhanced or Legacy Paging Procedures 496 Events, Paging Procedures 500 Scenarios 504 Events 505 Events 517 Events 518 Events 521 Events 528 Events 530 Events 532 Events 533 Events 590 Procedure for transitioning to inactive state 592 Events 594 Events 596 Events, Enhanced or Legacy Paging Procedures 600A Scenario 600B Scenario 600C Scenario 602 System Information 621 steps 622 Events 624 Events 626 Events 628 Events 630 Events 632 Events 639 Paging 641 Paging 650 events, steps 652 steps 654 steps 656 steps 658 steps 660 steps 662 steps 664 steps 686 Event, Resumption Procedures 690 Event, Procedure for Transitioning to Inactive State 692 Events, Registration Procedures 694 Events, Enhanced or Legacy Paging Procedures 696 Event, Enhanced or Legacy Paging Procedures 700A Scenario 700B Scenario 700C Scenario 700D Scenario 703 Events 718 RRC Release Message 727 Events 729 Event, Message from CN to BS 730 Events 731 Event, Message from CN to BS 732 Events 734 Events 740 RRC Release Message 752 Events 753 Events 754 Event, Message from CN to BS 756 Events 763 Events 782 Events 784 Emergency PDU Session Release Procedure 786 Restart Procedure 790 Event, Procedure for Transitioning to Inactive State 794 Events, Enhanced or Legacy Paging Procedures 796 Events 797 Events 798 Event, Enhanced Paging Procedures 799 Events, Legacy Paging Procedures 800 ways 802 Events 804 Events 806 Events 808 Events 900A Method 900B method 907 Events 1000 ways 1004 Events 1100 methods 1102 Event 1200A method 1200B Method 1202 Events 1206 Events 1208 Event 1300A method 1300B Method 1300C method 1302 Events 1400A method 1400B Method 1402 Events 1406 Events 1412 Events 1500 ways 1504 Events 1600 methods 1602 Events 1700 methods 1702 Events 1800 methods 1900 method 2000 methods

Claims

1. 1. A computer-implemented method for managing paging subgrouping implemented in a user equipment (UE) operating in communication with a core network (CN) via a cell of a radio access network (RAN), comprising: sending a support message from the UE to the CN indicating support for paging subgrouping; receiving, at the UE, a configuration of a paging subgroup from the CN; receiving, at the UE, from the RAN, configuration parameters indicating resources for the UE to receive PEI signals corresponding to the paging subgroup; and receiving, at the UE, the PEI signal based on at least the configuration parameters.

2. 2. The computer-implemented method of claim 1, further comprising receiving, at the UE, from the RAN, a message associated with a protocol for controlling radio resources, the message (i) indicating that the UE should transition to an idle or inactive state associated with the protocol, and (ii) including a list of cells supporting paging subgrouping.

3. 10. The computer-implemented method of claim 1, wherein receiving the configuration of the paging subgroups comprises receiving the configuration of the paging subgroups in a registration accept message.

4. selecting or reselecting a new cell after receiving said configuration parameters; 10. The computer-implemented method of claim 1, further comprising: in response to determining that the cell and the new cell belong to the same RAN notification area, determining that the new cell supports paging subgrouping.

5. The step of receiving a PEI signal, receiving, at the UE, a paging indication from the RAN; The computer-implemented method of claim 1 , wherein receiving the PEI signal is further based on the paging indication.

6. 2. The computer-implemented method of claim 1, wherein transmitting the support message comprises transmitting the support message within an uplink non-access stratum message.

7. 2. The computer-implemented method of claim 1, comprising sending the support message before transitioning from a connected state associated with a protocol for controlling radio resources to an idle or inactive state associated with the protocol.

8. 2. The computer-implemented method of claim 1, comprising sending the support message in response to at least one of: (i) a determination that the UE is configured to support paging subgrouping for a public land mobile network (PLMN) with which the cell is associated; (ii) a determination that the cell supports paging subgrouping; or (iii) a selection or reselection of the cell.

9. The method of claim 8, wherein the step of receiving a PEI signal comprises:

2. The computer-implemented method of claim 1, comprising receiving the PEI signal in accordance with the configuration parameters in at least one of (i) an idle state associated with a protocol for controlling radio resources, or (ii) an inactive state associated with a protocol for controlling radio resources.

10. 2. The computer-implemented method of claim 1, further comprising: determining at the UE to cease using the configuration parameters to monitor paging in response to determining that the UE has established an emergency PDU session.

11. 1. A computer-implemented method for managing paging subgrouping for a user equipment (UE), the method being implemented in a core network (CN), comprising: receiving, at the CN, a UE support message indicating support for paging subgrouping; sending a paging subgroup configuration from the CN to the UE; sending configuration parameters from the CN to a Radio Access Network (RAN) associated with the CN indicating resources for the UE to receive PEI signals corresponding to the paging subgroup; and sending, by the CN to the RAN, a message to be paged to the UE according to the configuration of the paging subgroups.

12. 12. The computer-implemented method of claim 11, further comprising determining whether a message associated with the UE, destined for the base station in a RAN associated with the CN, should include the configuration of the paging subgroups based at least in part on whether the base station supports paging subgrouping.

13. 13. The computer-implemented method of claim 12, wherein determining whether the message should include the configuration of the paging subgroup is further based on whether the UE does not have an emergency PDU session.

14. 14. Apparatus comprising processing hardware and configured to perform the method of any one of claims 1 to 13.

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