Apparatus and method for determining whether a user equipment is located within a registered area

Abstract

A user equipment (UE), a base station, and an AMF (Access and Mobility Management Function) system, as well as a corresponding method and integrated circuit, are provided, in which the UE determines whether it is located in a registration area indicated to the UE by the AMF and in which the UE is paged by the base station based on a combination of signal strength measurements or location and either a list of cell IDs of terrestrial mobile cells and timing or a stored mapping between geographical areas and tracking areas.

Description

Technical Field

[0001] The present disclosure relates to signal transmission and reception in a communication system. More particularly, the present disclosure relates to methods and apparatuses for such transmission and reception.

Background Art

[0002] The 3rd Generation Partnership Project (3GPP) is working on the technical specifications of the next-generation cellular technology, also known as the fifth generation (5G), which includes the "New Radio" (NR) radio access technology (RAT) operating in a frequency range up to 100 GHz. NR is a successor to the technologies represented by Long Term Evolution (LTE) and LTE Advanced (LTE-A).

[0003] In systems such as LTE, LTE-A, and NR, further improvements and options can promote the efficient operation of the communication system and specific devices related to the system.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Non-Patent Document 6

[0005] One non-limiting and exemplary embodiment facilitates efficient paging for an NTN communication system having an earth moving cell.

[0006] In one embodiment, the technology disclosed herein is a user equipment (UE) that, in operation, sends a registration request that includes at least one of: · an indication of a first location of the UE, or · a cell ID of the last cell visited by the UE and a timestamp indicating a first time instant when the UE was located within the last cell, and Receive a registration acceptance message including a notification of a registration area, the registration area including the first position of the UE, a transceiver, in operation, · Based on a list of cell IDs of a plurality of terrestrial cells or cell sections of the terrestrial cells, a notification of a second time when the plurality of terrestrial cells form the registration area, for each of the plurality of terrestrial cells, coverage area information indicating a coverage area of the cell or cell section relative to a satellite position of a satellite generating the cell, ephemeris data of the satellite, and a measurement value of a second position of the UE, wherein the list of the plurality of terrestrial cells and the notification of the second time are included in the notification of the registration area, or, · Based on the list of the cell IDs, a notification of a time interval during which the plurality of terrestrial cells or cell sections form the registration area, the second position of the UE, and a cell ID of a newly visited cell or cell section different from the last cell, wherein the list of the cell IDs and the notification of the time interval are included in the notification of the registration area, or, · Based on the measurement value of the second position, a mapping between a geographical area and a tracking area, and a list of one or more tracking areas forming the registration area, wherein the mapping is read from storage and the list of the one or more tracking areas is included in the notification of the registration area, a circuit that determines whether the UE is located within the registration area at the second position, characterized by a user equipment.

[0007] Note that general or specific embodiments may be implemented as a system, method, integrated circuit, computer program, storage medium, or any optional combination thereof.

[0008] Further benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. Benefits and / or advantages may be individually obtained by various embodiments and features of the specification and drawings, and all of them are not necessarily provided to obtain one or more of such benefits and / or advantages.

[0009] Hereinafter, exemplary embodiments will be described in more detail with reference to the accompanying figures and drawings.

Brief Description of the Drawings

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Best Mode for Carrying Out the Invention

[0011] 5G NR System Architecture and Protocol Stack

[0012] 3GPP is working on the next release of 5G cellular technology, simply called 5G, which includes the development of a new radio access technology (NR) operating at frequencies up to 100 GHz. The first version of the 5G standard was completed at the end of 2017, enabling the progress of tests and commercial deployment of smartphones compliant with the 5G NR standard.

[0013] In particular, the overall system architecture assumes an NG-RAN (Next Generation - Radio Access Network) that includes a gNB (gNodeB) that provides NG radio access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC, Radio Resource Control) protocol terminations to the UE. The gNBs are interconnected by the Xn interface. The gNB is also connected to the NGC (Next Generation Core) by the Next Generation (NG) interface, and more specifically, is connected to the AMF (Access and Mobility Management Function) (e.g., a specific core entity that executes the AMF) by the NG-C interface, and is also connected to the UPF (User Plane Function) (e.g., a specific core entity that executes the UPF) by the NG-U interface. The NG-RAN architecture is shown in FIG. 1 (see, for example, section 4 of Non-Patent Document 1).

[0014] The user plane protocol stack of NR (see, e.g., section 4.4.1 of Non-Patent Document 1) includes PDCP (Packet Data Convergence Protocol, see section 6.4 of Non-Patent Document 1), RLC (Radio Link Control, see section 6.3 of Non-Patent Document 1), and MAC (Medium Access Control, see section 6.2 of Non-Patent Document 1) sublayers, which are terminated at the gNB on the network side. In addition, a new access stratum (AS) sublayer (SDAP, Service Data Adaptation Protocol) has been introduced on top of PDCP (see, e.g., sub-clause 6.5 of Non-Patent Document 1). A control plane protocol stack is also defined for NR (see, e.g., section 4.4.2 of Non-Patent Document 1). An overview of the layer 2 functions is given in sub-clause 6 of Non-Patent Document 1. The functions of the PDCP, RLC, and MAC sublayers are listed in sections 6.4, 6.3, and 6.2 of Non-Patent Document 1, respectively. The functions of the RRC layer are listed in sub-clause 7 of Non-Patent Document 1.

[0015] For example, the medium access control layer handles scheduling and scheduling-related functions including logical channel multiplexing and handling of various numerologies.

[0016] The physical layer (PHY) is responsible for, for example, encoding, PHY HARQ processing, modulation, multi-antenna processing, and mapping of signals to appropriate physical time-frequency resources. It also handles the mapping of transport channels to physical channels. The physical layer provides services to the MAC layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used for the transmission of a specific transport channel, and each transport channel is mapped to a corresponding physical channel. For example, physical channels include the PRACH (Physical Random Access Channel) for uplink, PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel), as well as the PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), and PBCH (Physical Broadcast Channel) for downlink.

[0017] The use cases / deployment scenarios of NR may include enhanced mobile broadband (eMBB), ultra-reliable and low-latency communication (URLLC), and massive machine type communication (mMTC), which have diverse requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps for downlink and 10 Gbps for uplink) and data rates experienced by users that are about three times the data rates provided by IMT-Advanced. On the other hand, in the case of URLLC, ultra-low latency (user plane latency of 0.5 ms for both UL and DL) and high reliability (1 to 10 within 1 ms) -5More stringent requirements are imposed on 2 ). Finally, mMTC may preferably require a high connection density (1,000,000 devices / km in an urban environment

[0018] ), wide coverage in harsh environments, and extremely long-lived batteries (15 years) for low-cost devices. Therefore, an OFDM numerology suitable for a certain use case (e.g., subcarrier spacing, OFDM symbol duration, cyclic prefix (CP) duration, number of symbols per scheduling interval) may not function well in other use cases. For example, low-latency services may preferably require a shorter symbol duration (and thus a larger subcarrier spacing) than mMTC services, and / or fewer symbols per scheduling interval (also known as TTI). Furthermore, in deployment scenarios with a large channel delay spread, a longer CP duration may preferably be required than in scenarios with a short delay spread. The subcarrier spacing needs to be appropriately optimized to maintain a similar CP overhead. NR may support subcarrier spacings of two or more values. Correspondingly, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz,... are currently under consideration. The symbol duration T u and the subcarrier spacing Δf are directly related by the formula Δf = 1 / T u . Similar to the LTE system, the term "resource element" can be used to represent the smallest resource unit composed of one subcarrier over the length of one OFDM / SC-FDMA symbol.

[0019] In the new radio system 5G-NR, for each numerology and carrier, a resource grid of subcarriers and OFDM symbols is defined for each of the uplink and downlink. Each element in the resource grid is called a resource element and is identified based on the frequency index in the frequency domain and the symbol position in the time domain (see Non-Patent Document 2).

[0020] 5G NR Functional Split between NG-RAN and 5GC

[0021] Figure 2 shows the functional split between the NG-RAN and the 5GC. The logical nodes of the NG-RAN are the gNB or the ng-eNB (next-generation eNB). The 5GC has the logical nodes AMF, UPF, and SMF.

[0022] Specifically, the gNB and ng-eNB host the following main functions. - Functions for radio resource management, such as radio bearer control, radio admission control, connection mobility control, and dynamic allocation (scheduling) of resources to the UE for both uplink and downlink - Compression, encryption, and integrity protection of IP headers - Selection of the AMF at UE connection when the routing to the AMF from the information provided by the UE cannot be determined - Routing of user plane data to the UPF(s) - Routing of control plane information to the AMF - Setup and release of connections - Scheduling and transmission of paging messages - Scheduling and transmission of system broadcast information (sent from the AMF or OAM) - Configuration of measurements and measurement reports for mobility and scheduling - Transport-level packet marking on the uplink - Session management - Support for network slicing - QoS flow management and mapping to data radio bearers - Support for UEs in the RRC_INACTIVE state - Delivery function for NAS (Non-access stratum) messages - Radio access network sharing - Dual connectivity - Tight cooperation between NR and E-UTRA

[0023] The Access and Mobility Management Function (AMF) hosts the following main functions. - Non-Access Stratum NAS signaling termination - NAS signaling security - Access Stratum AS security management - Core Network CN node - to - CN node signaling for mobility between 3GPP access networks - Reachability of idle mode UEs (including control and execution of paging re - transmission) - Registration area management - Support for mobility within and between systems - Access authentication - Access authorization including roaming right check - Mobility management control (subscription and policy) - Support for network slicing - Selection of the Session Management Function (SMF)

[0024] Furthermore, the User Plane Function (UPF) hosts the following main functions. - Anchor point for RAT - in / RAT - between mobility (if applicable) - External PDU session point of interconnection to the data network - Packet routing & forwarding - User plane part of packet inspection and policy rule enforcement - Reporting of traffic usage - Uplink classifier to support routing of traffic flows to the data network - Branch point to support multi - home PDU sessions - QoS handling in the user plane, e.g., packet filtering, gating, UL / DL speed enforcement - Uplink traffic verification (mapping from SDF to QoS flow) - Downlink packet buffering and triggering of downlink data notifications

[0025] Finally, the Session Management Function SMF hosts the following main functions. - Session management - Allocation and management of the UE's IP address - Selection and control of the UP function - Configuration of traffic steering in the User Plane Function UPF for routing traffic to the appropriate destination - Policy enforcement and the QoS control part - Downlink data notification

[0026] RRC Connection Setup and Reconfiguration Procedures

[0027] Figure 3 shows some interactions between the UE, gNB, and AMF (5GC entity) in the context of the UE transitioning from RRC_IDLE to RRC_CONNECTED with respect to the NAS part (see Non-Patent Document 1).

[0028] RRC is the upper layer signaling (protocol) used for the configuration of the UE and the gNB. Specifically, this transition involves the AMF preparing UE context data (including, for example, PDU session context, security keys, UE radio capabilities, and UE security capabilities), and transmitting this to the gNB using an Initial Context Setup Request. The gNB then activates AS security with the UE, which is performed by the gNB sending a SecurityModeCommand message to the UE and the UE responding with a SecurityModeComplete message to the gNB. Thereafter, the gNB performs reconfiguration and sends an RRCReconfiguration message to the UE, and in response, the gNB receives an RRCReconfigurationComplete from the UE to set up Signaling Radio Bearer 2 (SRB2) and one or more Data Radio Bearers (DRBs). In the case of a signaling-only connection, the steps related to RRCReconfiguration are skipped as SRB2 and DRB are not set up. Finally, the gNB notifies the AMF using an Initial Context Setup Response that the setup procedure is complete.

[0029] Therefore, in the present disclosure, in operation, an entity (such as an AMF, SMF, etc.) of a 5th Generation Core (5GC) is provided that includes a control circuit for establishing a Next Generation (NG) connection with a gNodeB, and a transmitter for transmitting an Initial Context Setup message to the gNodeB via the NG connection to cause the gNodeB to set up a signaling radio bearer between the gNodeB and a User Equipment (UE). Specifically, the gNodeB transmits Radio Resource Control (RRC) signaling including a resource allocation configuration information element to the UE via the signaling radio bearer. The UE then performs uplink transmission or downlink reception based on the resource allocation configuration.

[0030] IMT Usage Scenarios after 2020

[0031] Figure 4 shows some of the use cases of 5G NR. In the new radio of the 3rd generation partnership project (3GPP NR), three use cases are being considered that are expected to support a wide variety of services and applications by IMT-2020. The specifications for Phase 1 of enhanced mobile broadband (eMBB) have been finalized. In addition to further expanding eMBB support, current and future work will include the standardization of ultra-reliable and low-latency communications (URLLC) and massive machine type communications. Figure 4 shows some examples of the usage scenarios assumed in IMT after 2020 (see, for example, Fig. 2 of Non-Patent Document 3).

[0032] The use cases of URLLC have strict requirements for capabilities such as throughput, latency, and availability, and are assumed to be one of the enablers for future vertical applications such as wireless control of industrial manufacturing or production processes, remote medical surgery, power distribution automation in smart grids, and transportation safety. The ultra-reliability of URLLC is supported by identifying technologies that meet the requirements set in Non-Patent Document 4. For NR URLLC in Release 15, the main requirements include a target user plane latency of 0.5 ms for UL (uplink) and 0.5 ms for DL (downlink). The general URLLC requirement for a single transmission of a packet is a BLER (block error rate) of 1E-5 for a packet size of 32 bytes with a user plane latency of 1 ms.

[0033] From the perspective of the physical layer, reliability can be improved in several conceivable ways. The current scope for improving reliability includes defining individual CQI tables for URLLC, more compact DCI (Downlink Control Information) formats, repetition of PDCCH, etc. However, as NR develops more steadily (with respect to the main requirements of NR URLLC), this scope can expand to achieve ultra-high reliability. Specific use cases of NR URLLC in Release 15 include Augmented Reality / Virtual Reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0034] Also, the technical extensions targeted at NR URLLC aim to improve latency and reliability. Technical extensions for improving latency include configurable numerology, non-slot-based scheduling using flexible mapping, grant-free (configured grant) uplink, slot-level repetition for data channels, and downlink preemption. Preemption means that a transmission for which resources have already been allocated is stopped and the resources already allocated to another transmission that was requested later but has lower latency requirements / higher priority requirements are used. Thus, a transmission that has already been granted is pre-empted by a later transmission. Preemption is applicable regardless of the specific service type. For example, a transmission of service type A (URLLC) can be pre-empted by a transmission of service type B (such as eMBB). Technical extensions for improving reliability include dedicated CQI / MCS tables for a target BLER of 1E-5.

[0035] The use cases of mMTC (Massive Machine Type Communication) are typically characterized by a very large number of connected devices that transmit relatively small amounts of data that are not latency-sensitive. The devices need to be inexpensive and have a very long battery life. From the perspective of NR, utilizing very narrow bandwidth parts is one possible solution to save power from the UE perspective and achieve a long battery life.

[0036] As described above, the scope of NR reliability is expected to be broader. One major requirement for all cases, especially those necessary for URLLC and mMTC, is high reliability or ultra-high reliability. Several mechanisms can be considered to improve reliability from both the radio and network perspectives. Generally, there are several major potential areas that can help improve reliability. Among these areas are compact control channel information, repetition of data / control channels, and diversity in the frequency, time, and / or spatial domains. These areas are generally applicable to reliability and are independent of specific communication scenarios.

[0037] For NR URLLC, additional use cases with more stringent requirements have been identified, including factory automation, the transportation industry, and power distribution. The more stringent requirements, depending on the use case, are higher reliability (up to a level of 10 -6 ), higher availability, a packet size of up to 256 bytes, time synchronization on the order of a few μs that can be 1 μs or a few μs depending on the frequency range, and a short latency on the order of 0.5 - 1 ms, especially a target user plane latency of 0.5 ms.

[0038] Also, in the case of NR URLLC, several technical extensions from the perspective of the physical layer have been identified. Among these are compact DCI, repetition of PDCCH, and extensions of PDCCH (Physical Downlink Control Channel) related to enhanced PDCCH monitoring. Also, the extension of UCI (Uplink Control Information) is related to the extension of enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback. Also, an extension of PUSCH related to hopping and retransmission / repetition extensions at the mini-slot level has been identified. The term "mini-slot" refers to a transmission time interval (TTI: Transmission Time Interval) that contains a smaller number of symbols than a slot (a slot containing 14 symbols).

[0039] In slot-based scheduling or allocation, a slot corresponds to the granularity of the timing of the scheduling allocation (TTI: transmission time interval). Generally, the TTI determines the granularity of the timing of the scheduling allocation. One TTI is the time interval during which a given signal is mapped to the physical layer. For example, conventionally, the TTI length can vary from 14 symbols (slot-based scheduling) to 2 symbols (non-slot-based scheduling). Downlink (DL: downlink) and up (UL: uplink) link transmissions are defined to be organized into frames (10 ms duration) consisting of 10 subframes (1 ms duration). In slot-based transmission, a subframe is further divided into slots, and the number of those slots is defined by the numerology / subcarrier spacing. The defined values range from 10 slots per frame (1 slot per subframe) when the subcarrier spacing is 15 kHz to 80 slots per frame (8 slots per subframe) when the subcarrier spacing is 120 kHz. The number of OFDM symbols per slot is 14 in the case of a normal cyclic prefix and 12 in the case of an extended cyclic prefix (see Physical channels and modulation, September 2018, Sections 4.1 (general frame structure), 4.2 (Numerologies), 4.3.1 (frames and subframes), and 4.3.2 (slots) of Non-Patent Document 5). However, the time resource allocation for transmission may also be non-slot-based. Specifically, the TTI for non-slot-based allocation may correspond to a mini-slot instead of a slot. That is, one or more mini-slots may be allocated for the transmission of the requested data / control signaling. In non-slot-based allocation, the minimum TTI length can be, for example, 1 or 2 OFDM symbols.

[0040] QoS Control

[0041] The 5G QoS (Quality of Service) model is based on QoS flows and supports both QoS flows that require a guaranteed flow bit rate (GBR: guaranteed bit rate QoS flows) and QoS flows that do not require a guaranteed flow bit rate (non-GBR QoS flows). Therefore, at the NAS level, a QoS flow is the finest granularity of QoS differentiation in a PDU session. A QoS flow is identified within a PDU session by a QoS flow ID (QFI: QoS flow ID) that is carried in a capsule header via the NG-U interface.

[0042] For each UE, the 5GC establishes one or more PDU sessions. For each UE, the NG-RAN establishes at least one data radio bearer (DRB) along with the PDU session and can later set additional DRBs (if any) for the QoS flows (if any) of that PDU session, as shown above with reference to Figure 3 (when to do so is up to the NG-RAN). The NG-RAN maps packets belonging to different PDU sessions to different DRBs. NAS-level packet filters in the UE and 5GC associate UL and DL packets with QoS flows, and AS-level mapping rules in the UE and NG-RAN associate UL and DL QoS flows with DRBs.

[0043] Figure 5 shows a 5G NR non-roaming reference architecture (see Section 4.23 of Non-Patent Document 6). An application function (AF), for example, an external application server that hosts the 5G services exemplarily shown in Figure 4, communicates with the 3GPP core network to provide services, for example, supports interaction with the policy framework for policy control such as the influence of the application on traffic routing, access to the network exposure function (NEF), or QoS control (see the policy control function PCF (Policy Control Function)). Based on the operator's arrangement, an application function regarded as trusted by the operator can be permitted to directly communicate with the relevant network functions. An application function not permitted by the operator to directly access the network functions uses the external exposure framework via the NEF to communicate with the relevant network functions.

[0044] Figure 5 shows further functional units of the 5G architecture, namely, the network slice selection function (NSSF), the network repository function (NRF), the unified data management (UDM), the authentication server function (AUSF), the access and mobility management function (AMF), the session management function (SMF), and the data network (DN), for example, operator services, Internet access, or third-party services, etc. All or part of the core network functions and application services can be deployed and executed in a cloud computing environment.

[0045] Therefore, in the present disclosure, during operation, a request including QoS requirements for at least one of URLLC, eMMB, and mMTC services is transmitted to at least one of the functions of the 5GC (for example, NEF, AMF, SMF, PCF, UPF, etc.), and a transmitter for establishing a PDU session including a radio bearer between the gNodeB and the UE in accordance with the QoS requirements, and during operation, a control circuit for executing a service using the established PDU session are provided, and an application server (for example, AF of the 5G architecture) including the above is provided.

[0046] In LTE and NR, the terminal is called a user equipment (UE). This can be a mobile device or a communication device such as a wireless phone, smartphone, tablet computer, or USB (Universal Serial Bus) stick having the functions of a user equipment. However, the term mobile device is not limited to this, and generally, a repeater may also have the functions of such a mobile device, and the mobile device may function as a repeater.

[0047] The base station is a network node or a scheduling node that forms a part of the network for providing services to the terminal, for example. The base station is a network node that provides wireless access to the terminal.

[0048] Figures 6 to 9 show some additional examples of the interaction between the AMF and the UE and the NG-RAN node (for example, gNB) for the example of Figure 3.

[0049] Specifically, Figure 6 shows the registration procedure. A registration request is transmitted from the UE to the AMF, and in response, a registration acceptance message is transmitted by the AMF. For example, the UE starts the registration procedure for initial registration, mobility registration update, or periodic registration update, etc.

[0050] On one hand, for example, when the AMF wants to update the UE configuration related to access and mobility related parameters, as shown in FIG. 7, the AMF may start the UE configuration update procedure. As shown in FIG. 7, the AMF sends a configuration update command, and in response, the UE sends a configuration update completion message.

[0051] The NG setup procedure between the NG-RAN node and the AMF is shown in FIG. 8. Specifically, the NG-RAN node (e.g., gNB) sends an NG setup request to the AMF and receives an NG setup response from the AMF. The NG setup procedure can be used to exchange application-level data (e.g., configuration data) required for the NG-RAN node and the AMF to interoperate correctly on the NG interface.

[0052] Furthermore, the RAN configuration update procedure can be used to update the application-level configuration data required for the NG-RAN node and the AMF to interoperate correctly on the NG interface. As shown in FIG. 9, the RAN configuration update procedure may include the NG-RAN node sending a RAN configuration update and receiving a RAN configuration update positive response in response.

[0053] RRC States

[0054] In a wireless communication system including NR, a device or communication apparatus (e.g., UE) can be in different states according to traffic activities. In NR, a device can be in one of three RRC states: RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE. The first two RRC states, namely RRC_IDLE and RRC_CONNECTED, are the same as their counterparts in LTE, and RRC_INACTIVE is newly introduced in NR and does not exist in the original LTE design. There are also core network states called CN_IDLE and CN_CONNECTED, which depend on whether the device has established a connection with the core network.

[0055] In RRC_IDLE, the RRC context, i.e., the parameters necessary for communication between the device and the network, does not exist in the radio access network, and the device does not belong to a specific cell. From the perspective of the core network, the device is in the CN_IDLE state. Since the device sleeps most of the time to reduce battery consumption, data transfer may not occur. In the downlink, an idle device wakes up periodically to receive paging messages from the network if there are any. Mobility is handled by the device through cell reselection. Uplink synchronization is not maintained, and thus the only uplink transmission activity that can occur is random access, for example, to transition to the connected state. As part of the transition to the connected state, the RRC context is established in both the device and the network.

[0056] In the RRC_CONNECTED state, the RRC context is established, and all the parameters necessary for communication between the device and the radio access network are known to both entities. From the perspective of the core network, the device is in the CN_CONNECTED state. The cell to which the device belongs is known, and a Cell Radio-Network Temporary Identifier (C-RNTI), which is the identification information of the device used for signaling between the device and the network, is set. The connected state aims at data transfer between the device, and discontinuous reception (DRX) can be set to reduce the power consumption of the device. Since the RRC context is established at the gNB in the connected state, starting data transmission and reception away from DRX is relatively fast because connection setup by the associated signaling is not required. Mobility is managed by the radio access network, that is, the device provides the network with measurement values of neighboring cells, and the network issues commands to the device to perform handover when relevant. Uplink time alignment may or may not exist, but it needs to be established and maintained using random access for data transmission to occur.

[0057] In LTE, only the idle state and the connected state are supported. In the actual general case, the idle state is used as the primary sleep state to reduce the power consumption of the device. However, frequent transmission of small packets is common in many smartphone applications, and as a result, a significant amount of transition from idle to active occurs in the core network. These transitions involve sacrifices in terms of signaling load and related delays. Therefore, in NR, the RRC_INACTIVE state, which is the third state, is defined to reduce the signaling load and generally reduce the delay.

[0058] In RRC_INACTIVE, the RRC context is maintained at both the device and the gNB. The core network connection is also maintained, i.e., the device is CN_CONNECTED from the perspective of the core network. Therefore, the transition to the connected state for data transfer is fast. Core network signaling is not required. The RRC context is already in place within the network and can handle the transition from idle to active within the radio access network. At the same time, the device can sleep in a similar manner to the idle state, and mobility is handled through cell reselection, i.e., without network involvement. Therefore, the mobility of the communication device or device is device-controlled rather than network-controlled, and the communication device can contact the network via random access. Therefore, RRC_INACTIVE can be regarded as a mixture of the idle state and the connected state (for details, refer to Sections 6.5.1 to 6.5.3 of Non-Patent Document 7).

[0059] Paging Procedures in 5G NR

[0060] An exemplary implementation of the paging function in 5G NR including PDCCH monitoring, compliant with the currently standardized version, will be described in a simplified abbreviated form below.

[0061] There are two different paging procedures in 5G NR, the RAN-based paging procedure (e.g., based on the RAN-based notification area), and the core network-based paging procedure (for which reference should be made to Non-Patent Document 1, Non-Patent Document 8, and Non-Patent Document 9, which mention RAN paging and CN paging in some of their sections, such as Section 9.2.5 "Paging" of Non-Patent Document 1).

[0062] Through paging, the network can reach UEs in the RRC_IDLE and RRC_INACTIVE states via paging messages, and can notify UEs in the RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED states of system information changes and public warning information (e.g., ETWS / CMAS, Earthquake and Tsunami Warning System / Commercial Mobile Alert System) notifications via short messages. Both paging messages and short messages are addressed with the P-RNTI on the PDCCH monitored by the UE. However, the actual paging message (e.g., including the paging record) is then transmitted on the PCCH (as indicated by the PDCCH), while the short message can be directly transmitted via the PDCCH.

[0063] In RRC_IDLE, the UE monitors the paging channel for paging initiated by the CN, while in RRC_INACTIVE, the UE also monitors the paging channel for paging initiated by the RAN. However, the UE does not need to continuously monitor the paging channel, and paging DRX is defined. A UE in RRC_IDLE or RRC_INACTIVE only needs to monitor the paging channel during one paging occasion (PO) per DRX cycle (see Non-Patent Document 10, e.g., Sections 6.1 and 7.1). The paging DRX cycle is set by the network.

[0064] The Paging Opportunities (POs) of a UE in CN-initiated paging and RAN-initiated paging are based on the same UE ID, so both POs overlap. The number of different POs within a DRX cycle can be configured via system information, and the network can distribute UEs to those POs based on the ID. A PO is a set of PDCCH monitoring occasions and can consist of multiple time slots (e.g., subframes or OFDM symbols) in which paging DCI can be transmitted. One paging frame (PF) is one radio frame and can include one or more POs (multiple allowed) or the starting points of POs.

[0065] In the case of RRC_CONNECTED, the UE monitors the paging channel for system information change notifications and / or PWS (Public Warning System) notifications at the POs signaled in the system information. In the case of bandwidth adaptation (BA) (see Section 6.10 of Non-Patent Document 1), an RRC_CONNECTED UE monitors only the paging channel on the active BWP where the common search space is configured.

[0066] When the UE receives a paging message, PDCCH monitoring can be stopped by the UE. Depending on the cause of the paging, the UE can continue, for example, to acquire system information or establish an RRC connection with the base station to receive traffic / commands from the network.

[0067] Tracking Area and Tracking Area Code

[0068] Since the location of the UE is typically known at the cell level, paging messages are typically sent across multiple cells within a so-called tracking area (TA) that can be controlled by the AMF / MME (Mobility Management Entity).

[0069] A group of neighboring gNBs can be defined as a TA. This definition can be executed, for example, during the initial deployment of the network, and the TA can be set for each gNB. The Tracking Area Code (TAC) is a unique code assigned to each TA.

[0070] Since the network needs to have updated location information about the UE in RRC_IDLE in order to find out which TA a particular UE is located in, the UE can notify the network of its current location by sending a tracking area update (TAU) message each time it moves between TAs.

[0071] For this purpose, when the UE connects to the network, a list indicating the TA that the network considers the UE to be located in is obtained. When moving within the TA indicated by the above list, there is no need to execute the TAU procedure. However, when the UE moves to a TA not indicated by the above list, the TAU procedure is started.

[0072] Furthermore, a UE in RRC_IDLE can send TAU messages in a regular and periodic manner even when the UE remains in the same TA. By regularly providing TAU messages, the network can be notified that the UE is still available and can receive data.

[0073] The tracking area code associated with the cell can be broadcast in the system information by each gNB.

[0074] Registration Area

[0075] As described above, in order to efficiently page a UE when the UE is in the idle state, the tracking area (TA) is used to track UE mobility at the core network level (e.g., by the AMF). Each UE is assigned a list of TAI (tracking area identifier) (e.g., as the TA list described above) Registration Area (RA) by the core network. Generally, the registration area is UE-specific and can be different for different UEs even in similar locations (e.g., for load distribution).

[0076] When the core network needs to page a UE (e.g., when there is downlink data to be sent to the UE), it sends a paging message to one or more gNBs, and one or more gNBs perform paging of the UE in all cells belonging to the registration area.

[0077] The relationship between the registration area, the tracking area, and the cell is shown in FIG. 10, and both tracking areas TAI1 and TAI2 include a plurality of cells. For example, the registration area assigned to a UE may be registration area = {TAI1, TAI2}. In this example, the gNB provides service to a single cell. However, the present disclosure is not limited to a specific relationship between the gNB (or base station) and the cell, and the gNB may also provide service to a plurality of cells.

[0078] When the UE moves to a cell outside the area defined by the RA, it needs to access the network and execute a mobility registration update procedure. In the mobility update procedure, if the registration procedure shown in FIG. 6 can be used, the UE reports the TAI to the network via a registration request message. Then, the core network provides the UE with a new TA list including the new TAI in a registration acceptance message. In this way, a new registration area is assigned to the UE.

[0079] Therefore, when moving to a new cell, the UE needs to determine whether it is within the same RA. To know whether it is still within the same RA, the UE considers the TAC associated with the cell. Each cell broadcasts in the system information (e.g., SIB1, i.e., system information block 1) the TAC associated with it (tracking area code of the TA to which the cell belongs) and the PLMN ID (public land mobile network identity). When the UE visits or camps on a new cell, the UE reads the system information and derives the TAI by cascading the TAC with the PLMN ID or by adding the TAC to the PLMN ID (TAI = PLMN ID + TAC). Then, the UE compares the derived TAI with the list of TAIs within the RA. Here, "camping" on a cell includes at least one of starting to monitor paging, reading SIBs from the cell, and performing measurements using the RS from the cell.

[0080] Non-Terrestrial Network (NTN)

[0081] In 3GPP, NR-based operation in non-terrestrial networks (NTN) has been studied and described (see, for example, Non-Patent Document 11 and Non-Patent Document 12).

[0082] Thanks to its wide service coverage capabilities and the reduced vulnerability of spacecraft / aircraft to physical attacks and natural disasters, NTN can facilitate the introduction of NR services to service-unserved areas that cannot be covered by terrestrial NR networks (e.g., isolated areas or remote locations, inside aircraft or ships) and where services are not provided (e.g., suburbs and rural areas). Furthermore, NTN can enhance the reliability of NR services by providing service continuity to passengers on moving platforms or enabling service availability anywhere, especially for critical communications.

[0083] The advantages are related to either a non-terrestrial network operating independently or an integrated terrestrial and non-terrestrial network, which can affect coverage, user bandwidth, system capacity, service reliability or availability.

[0084] A non-terrestrial network refers to, for example, a network or a segment of a network that uses RF resources mounted on satellites. NTN typically features the following system elements, namely, NTN terminals that can refer to 3GPP UEs or, when the satellite does not directly provide services to 3GPP UEs, terminals specific to the satellite system, service links that refer to the radio links between user equipment and space / air platforms, space / air platforms carrying payloads, gateways that connect space / air platforms to the core network, and feeder links that refer to the radio links between gateways and space / air platforms.

[0085] FIG. 11 shows a scenario of a non-terrestrial network in which transmission between a terminal (UE) is performed via a remote radio unit including a satellite and an NTN gateway. The gNB is arranged at the gateway as a scheduling device. The satellite payload implements frequency conversion and radio frequency amplifiers in both the uplink and downlink directions. Thus, the satellite repeats the NR radio interface from the feeder link (between the NTN gateway and the satellite) to the service link (between the satellite and the UE), and vice versa. The satellite of this configuration is called a transparent satellite.

[0086] FIG. 12 shows a scenario of a non-terrestrial network in which transmission between a terminal (UE) is performed via a satellite including a gNB as a scheduling device. The satellite of this configuration is called a regenerative satellite.

[0087] In NTN, there can be various types of platforms including satellites and UAS (Unmanned Aerial System) platforms, and examples thereof are listed in Table 1 (which is the corresponding Table 4.1-1 in Non-Patent Document 12, see also Non-Terrestrial Networks overview in Section 4.1 of Non-Patent Document 12).

[0088]

Table 1

[0089] In the case of LEO, MEO, and HEO satellites that do not keep their positions fixed with respect to a given point on the Earth, the satellite beam corresponding to a cell or PCI (Physical Cell ID) or SSB (Synchronization Signal Block) beam of the NR wireless system can move on the Earth.

[0090] Regarding the mapping between satellite beams, NR cells, and NR SSB beams, different deployment options, such as options a and b shown in FIGS. 13 and 14, can be considered. According to deployment option a shown in FIG. 13, one cell (corresponding to PCI) has multiple satellite beams (e.g., the same PCI for multiple satellite beams), and according to deployment option b shown in FIG. 14, one cell corresponds to one satellite beam (one PCI exists for each satellite beam).

[0091] A satellite beam can consist of one or more SSB beams. For example, one satellite beam can be mapped to one SSB beam, e.g., there is a one-to-one correspondence between the satellite beam and the SSB beam. Here, the beam used to transmit the NR synchronization signal block is called the SSB beam. One NR cell (PCI) can have a maximum of L SSB beams, where L can be 4, 8, or 64 depending on the bandwidth. The SSB beam can be used as a reference beam for beam management in NR.

[0092] The NTN scenario that provides a cell that continuously moves on the earth (e.g., LEO, MEO, or HEO-based NTN) is called the earth-mobile cell scenario. The earth-mobile cell scenario is shown in FIG. 15. The continuous movement of the cell on the earth is due to the operation in which the satellite beam is fixed to the NTN platform. Therefore, the footprint of the cell that can correspond to several satellite beams or one satellite beam according to the above-described deployment options a and b slides on the earth's surface as the NTN platform (e.g., the LEO satellite shown in FIG. 15) moves.

[0093] Information regarding the orbital trajectories of satellites is included in ephemeris data (or "satellite ephemeris data"). There are various possible representations of ephemeris data, and one possibility is to use orbital parameters such as, for example, semi-major axis, eccentricity, inclination angle, right ascension of the ascending node, argument of perigee, mean anomaly at a reference time, and epoch. The first five parameters can determine the orbital plane (orbital plane parameters), and the other two parameters are used to determine the exact position of a satellite at a certain time (satellite level parameters). The orbital plane parameters and satellite level parameters are listed in Table 2 and shown in Figure 16 (see also Representation of Complete Ephemeris Data in Section 7.3.6.1 of Non-Patent Document 12). Another possible option is to provide the coordinates (x, y, z) of the satellite position, the velocity vector (vx, vy, vz), and the reference time.

[0094]

Table 2

[0095] Therefore, the representation of ephemeris data may require seven parameters (e.g., double-precision floating-point numbers) and possibly some overhead. In an NTN system, several satellites may share a common orbital plane. In such a case, to reduce the data volume, some ephemeris data can be provided with respect to the orbital plane rather than a single satellite. The ephemeris data for each orbital plane can be stored in the UE or the UE's Subscriber Identity Module (SIM).

[0096] However, in the case of a network with many satellites, the size of the ephemeris data can become quite large. Therefore, instead of storing the ephemeris data, the ephemeris data can be transmitted at least partially from the gNB.

[0097] For example, the satellite-level orbit parameters of all satellites that can provide services to the UE can be stored in the UE or the SIM, and the ephemeris data of each satellite is linked to a satellite ID or index. Then, the satellite ID or index of the service-providing satellite can be broadcast in the system information, and as a result, the UE can find the corresponding ephemeris data in the UE's SIM or storage.

[0098] Alternatively, the satellite-level orbit parameters of the service-providing satellite can be broadcast in the system information, and the UE derives the position coordinates of the service-providing satellite. The ephemeris data of neighboring satellites can also be provided to the UE via system information or dedicated RRC signaling. If the baseline orbital plane parameters are provisioned in the UE or the SIM, it may be sufficient to only broadcast the mean anomaly at a reference time, and since the epoch does not need to be broadcast to the UE, the overhead can be reduced.

[0099] As described above with reference to FIG. 15, the earth-moving cell scenario is an NTN scenario that provides cells that continuously move on the earth. This is due to an operation in which the satellite beam is fixed to the NTN platform. Therefore, the footprint of the satellite beam slides on the earth's surface as the NTN platform (e.g., a LEO satellite) moves.

[0100] As also described above, there is an association between a cell and a tracking area. However, in the earth-moving cell scenario, if the TAC broadcast by the cell does not change, this means that the TA sweeps the ground as the cell moves. In the case of such a moving tracking area, even a stationary UE needs to continuously perform frequent registration updates, which results in additional overhead and power consumption.

[0101] For these reasons, instead of a tracking area that moves, a fixed tracking area for NTN can be considered. Thus, the tracking area corresponds to a fixed geographical location on the earth. In the case of a moving cell, the fixed TA can be realized in the following two ways. According to one approach, the TAC broadcast by the (moving) cell changes when the cell covers different geographical areas. According to another approach, the TAC is not broadcast, and the UE derives the registration area in other ways, for example, from its own location information.

[0102] Regarding the mapping between the cell and the tracking area, the options of "hard switch" and "soft switch" can be considered. A hard switch means that one cell broadcasts only one TAC for each PLMN. When the new TAC of the cell replaces the old one, some fluctuations may occur in the boundary area between TAs. On the other hand, in the "soft switch" option, one cell can broadcast two or more TACs for each PLMN. The cell adds the new TAC to the system information in addition to the old one and deletes the old one a little later. However, the overhead may increase by signaling more TACs (see also Section 7.3.1.3.1 of Non-Patent Document 12 for hard switches and soft switches).

[0103] In the following, some details regarding location-based TA determination will be described. Specifically, it can be considered to divide the earth into a plurality of geographical areas corresponding to TAs. The mapping rules between the geographical areas and the associated TAC values can be maintained both in the UE and the network.

[0104] For example, during initial registration, the UE derives a TAC based on its location information and mapping rules, and then forms a TAI from the derived TAC and the broadcast PLMN ID. The UE then reports the TAI to the AMF via a registration request message. The AMF then provides the UE with a TAI list that includes the TAI reported via the registration acceptance message.

[0105] When the UE moves to a new geographical area, the UE derives a TAC based on its location information and mapping rules, and then forms a TAI from the TAC and the broadcast PLMN ID. If the formed TAI is not in the TAI list, a mobility registration update procedure is triggered. At this time, the UE reports the TAI to the AMF via a registration request message. The AMF provides the UE with a TAI list that includes the reported TAI via the registration acceptance message. The UE then replaces the old TAI list with the new one that includes the reported TAI (see also Section 7.3.1.3.2 of Non-Patent Document 12).

[0106] Regarding the above TA determination mechanism, it is generally unclear how the mapping rules between the geographical area and the TAC become available to the UE. Furthermore, as a specific example, when cell selection or reselection is based on radio signal strength and the TAC is not broadcast, for example, when the positioning function is unavailable, it is unclear how the UE determines that it is still within the RA.

[0107] Furthermore, due to the moving cell, there is no fixed relationship between the cell and the registration area. When the core network needs to page the UE, it is unclear what information is required for the AMF to select the gNB(s) to deliver the paging message and how such information is obtained for the gNB to select the cell(s) to page the UE.

[0108] The present disclosure is directed to determining a tracking area and handling paging for a non-terrestrial network.

[0109] In the present disclosure, scheduling nodes such as UEs and base stations, and corresponding methods are described. These are for a new radio access technology assumed for 5G mobile communication systems such as 3GPP NR, but can also be used in LTE mobile communication systems.

[0110] Accordingly, a communication device (or user terminal or communication terminal) is referred to as a UE (user equipment), and a scheduling node such as a base station may correspond to a gNodeB (gNB).

[0111] Also, some of the terms such as procedures, entities, layers, etc. used below are closely related to the terms used in the LTE / LTE-A system or the current 3GPP 5G standardization. However, specific terms used in the context of the new radio (NR) access technology of the next 3GPP 5G communication system have not yet been fully determined or may ultimately be changed. For this reason, the terms may be changed in the future without affecting the functions of the embodiments. Accordingly, those skilled in the art will recognize that the embodiments and their scope of protection should not be limited to the specific terms exemplified herein due to the lack of newer or finally agreed terms.

[0112] Communication devices or apparatuses such as a UE, and a scheduling node or a base station may include circuits such as a transceiver and a processing circuit. In turn, the transceiver may include and / or function as a receiver and a transmitter. The processing circuit may be one or more processors or one or more hardware such as any LSI (Large Scale Integration). There is an input / output point (or node) between the transceiver and the processing circuit, through which the processing circuit can control the transceiver during operation, that is, control the receiver and / or the transmitter, and exchange receive / transmit data. The transceiver may include an RF (radio frequency) front end including one or more antennas, amplifiers, RF modulators / demodulators, etc. as the transmitter and the receiver. The processing circuit may perform control tasks such as controlling the transceiver to transmit user data and control data provided by the processing circuit and / or receive user data and control data to be further processed by the processing circuit. The processing circuit may also be responsible for performing other processes such as determining, deciding, calculating, measuring, etc. The transmitter may be responsible for performing transmission processing and other related processes. The receiver may be responsible for performing reception processing and other related processes, such as monitoring a channel.

[0113] Communication devices such as a UE and a base station, and core network entities such as an AMF system may include circuits, which may include a processing circuit and a control circuit.

[0114] A user equipment (UE) 1770 is provided. As shown in FIG. 17, the UE includes a transceiver 1780, which transmits a registration request during operation. The registration request (or "registration request message") is · a notification of the first position of the UE, or · the cell ID of the last cell visited by the UE and a timestamp indicating the first time when the UE was located within the last cell, includes at least one of them.

[0115] The transceiver 1780 (or "UE transceiver") of UE 1770 receives a registration acceptance message including a notification of a registration area (RA), and the registration area includes a first position of the UE.

[0116] UE 1770 further includes a circuit 1790 (or "UE circuit"), and the circuit 1790 determines, during operation, whether the UE is located within the registration area at a second position. The determination as to whether the UE exists within the registration area is made based on at least one of the following. · A list of cell IDs of a plurality of terrestrial cells or cell sections of terrestrial cells, a notification of a second time when the plurality of terrestrial cells form a registration area, for each of the plurality of terrestrial cells, coverage area information indicating a coverage area of the cell or cell section relative to the satellite position of the satellite generating the cell, and ephemeris data of the satellite, and a measurement value of the second position of the UE. The list of the plurality of terrestrial cells and the notification of the second time are included in the notification of the registration area. Or, · A list of cell IDs, a notification of a time interval during which a plurality of terrestrial cells or cell sections form a registration area, and the second position of the UE, and a cell ID of a newly visited cell or cell section different from the last cell. The list of cell IDs and the notification of the time interval are included in the notification of the registration area. Or, · A measurement value of the second position, a mapping between a geographical area and a tracking area, and a list of one or more tracking areas forming a registration area. The mapping is read from storage, and the list of one or more tracking areas is included in the notification of the registration area.

[0117] The user equipment 1770 is a mobile device, a communication device, or a mobile terminal of a wireless communication system.

[0118] For example, UE circuit 1790 may include an RA positioning circuit 1795. An exemplary RA positioning circuit 1795 is shown in FIG. 18, which includes an RA determination circuitry 1896 and an RA decision circuitry 1897.

[0119] A base station 1740 is further provided and is also shown in FIG. 17. The base station 1740 includes an interface 1755 (also referred to as a "base station interface"), and the interface 1755 receives a paging request for paging the UE during operation. The paging request includes a notification of the registration area. The base station further includes a circuit 1760 (a "base station circuit"), and the circuit 1760, during operation, · Based on a list of cell IDs of a first plurality of terrestrial mobile cells or cell sections of a terrestrial mobile cell, a notification of a second time when the first plurality of terrestrial mobile cells form a registration area, and for each of the first plurality of terrestrial mobile cells, coverage area information indicating a coverage area of the cell or cell section relative to the satellite position of the satellite generating the cell and ephemeris data of the satellite (the list of the first plurality of terrestrial mobile cells and the time notification are included in the registration area notification), or, · Based on a list of cell IDs and a notification of a time interval during which a first plurality of terrestrial mobile cells or cell sections form a registration area (the list of cell IDs and the time interval notification are included in the registration area notification), or, · Based on a mapping between a geographical area and a tracking area and a list of one or more tracking areas forming a registration area (the mapping is read from storage and the list of one or more tracking areas is included in the registration area notification), determine a second plurality of terrestrial mobile cells. The second plurality of terrestrial mobile cells are a plurality of cells currently mapped to the registration area. The base station 1740 further includes a transceiver 1750 that transmits a paging message for paging the UE within the second plurality of cells during operation.

[0120] For example, the base station circuit 1760 includes an RA determination circuit 1765.

[0121] The base station 1740 is a scheduling node or a scheduling device of a wireless communication system such as a gNB of 3GPP NR in which a non-terrestrial network is implemented. Therefore, the terrestrial mobile cell is serviced by a satellite (e.g., LEO) or other non-terrestrial platform such as an airship or a balloon. For example, the communication system is an NR-NTN communication system. The communication system may include the terrestrial mobile cell alone, or in combination with, or supplemented by, for example, a fixed cell generated by a terrestrial base station. The UE 1770 and the base station 1740 communicate via a wireless channel. The present disclosure is not limited to a specific relationship between the base station and the satellite, and a communication system implementing both a regenerative satellite and a transparent satellite shown in FIGS. 11 and 12, or both regenerative and transparent satellites, is possible.

[0122] Furthermore, the base station communicates with a core network entity or system such as the AMF via the interface 1755.

[0123] In the above description of the base station, the "first plurality of cells" refers to terrestrial mobile cells that define a registration area in association with information regarding the time (time or time interval) during which the first plurality of cells constitute the registration area. On the other hand, the "second plurality of cells" is the cell in which the UE is paged. As will be further described, the second plurality of cells is determined based on the first plurality of cells.

[0124] The base station may service one cell or a number of two or more cells. Also, the registration area may be larger than the number of cells serviced by the base station 1740. Therefore, the "second plurality of cells" determined by the base station to page the UE may cover the entire registration area or a sub-area of the registration area.

[0125] As also shown in FIG. 17, an Access Mobility and Management Function (AMF) system 1710 is disclosed. The AMF system 1710 includes an interface 1720 (“AMF interface”) and a circuit 1730 (AMF circuit). When operating, the AMF interface 1720 receives a registration request from a UE, and the registration request includes · notification of the UE's first location, or · the cell ID of the last cell visited by the UE and a timestamp indicating the first time the UE was located within the last cell, and includes.

[0126] The AMF circuit 1730 generates a notification of a registration area that includes the UE's first location. The notification of the registration area includes · a list of cell IDs of a plurality of terrestrial cells or cell sections of a terrestrial cell and a notification of a second time at which the plurality of terrestrial cells form a registration area (the registration area is determined based on coverage area information and satellite ephemeris data of the cell or cell section relative to the satellite position of the satellite generating the cell for each of the plurality of terrestrial cells or cell sections), or · a list of cell IDs and a notification of a time interval during which a plurality of terrestrial cells or cell sections form a registration area, or · a list of one or more tracking areas that form a registration area (the list of one or more tracking areas is determined based on a mapping between a geographical area and the tracking area, and the mapping is read from storage).

[0127] When operating, the AMF interface 1720 transmits a registration acceptance message that includes a notification of the registration area.

[0128] The AMF system 1710 is an AMF entity of a core network such as the 5G core. For example, the AMF system can be implemented as a server or within a server hosting additional core network entities, or can be distributed among multiple nodes.

[0129] The AMF system 1710 and the base station 1740 perform communication via interfaces 1720 and 1755. For example, interfaces 1720 and 1755 form an NG interface. The AMF system 1710 and the base station 1740 can perform communication by means of a wired connection (which may include an optical fiber cable) or a wireless connection (such as in a regenerative satellite scenario) via interfaces 1720 and 1755. The base station interface 1755 can be included in the base station transceiver 1750 or can be separate from the base station transceiver 1750.

[0130] For example, as shown in FIG. 17, the AMF circuit 1730 includes an RA determination circuit 1735.

[0131] As described above, the UE 1770 and the AMF 1710 exchange a registration request message and a registration acceptance message. This exchange can be performed via the base station 1740, and the base station 1740 can transfer these control messages of the registration procedure. At this time, when operating, the base station transceiver 1750 can receive a registration request message from the UE and transmit a registration acceptance message to the UE. Similarly, the base station interface 1755 can transmit a registration request message to the AMF and receive a registration acceptance message from the AMF.

[0132] Corresponding to the user equipment described above, a communication method for a user equipment (UE) is provided. As shown in FIG. 19, this method includes a step S1910 of transmitting a registration request, and the registration request is · notification of the first location of the UE, or · the cell ID of the last cell visited by the UE and a timestamp indicating the first time when the UE was located within the last cell, includes at least one of them.

[0133] This method includes step S1920 of receiving a registration acceptance message including a notification of a registration area, where the registration area includes the first position of the UE. Also, this method includes step S1930 of determining, and step S1930 of determining is · Based on a list of cell IDs of a plurality of terrestrial cells or cell sections of a terrestrial cell, a notification of a second time when the plurality of terrestrial cells form a registration area, for each of the plurality of terrestrial cells, coverage area information indicating a coverage area of the cell or cell section relative to the satellite position of the satellite generating the cell, ephemeris data of the satellite, and a measurement value of the second position of the UE (the list of the plurality of terrestrial cells and the notification of the second time are included in the notification of the registration area), or · Based on a list of cell IDs, a notification of a time interval when a plurality of terrestrial cells or cell sections form a registration area, including the second position of the UE, and the cell ID of a newly visited cell or cell section different from the last cell (the list of cell IDs and the notification of the time interval are included in the notification of the registration area), or · Based on a measurement value of the second position, a mapping between a geographical area and a tracking area, and a list of one or more tracking areas forming the registration area (the mapping is read from storage and the list of one or more tracking areas is included in the notification of the registration area), determines whether the UE is located within the registration area at the second position.

[0134] Corresponding to the above base station, a communication method for the base station is further disclosed. This method shown in FIG. 20 includes step S2010 of receiving a paging request for paging a user equipment (UE) including a notification of a registration area. This method further includes step S2020 of determining, and step S2020 of determining is · A list of cell IDs of the first plurality of terrestrial cells or cell sections of a terrestrial cell, a notification of a second time at which the first plurality of terrestrial cells form a registration area, and for each of the first plurality of terrestrial cells, based on coverage area information indicating the coverage area of the cell or cell section relative to the satellite position of the satellite generating the cell and the ephemeris data of the satellite (the list of the first plurality of terrestrial cells and the notification of the time are included in the notification of the registration area), or, · Based on a list of cell IDs and a notification of a time interval during which the first plurality of terrestrial cells or cell sections form a registration area (the list of cell IDs and the notification of the time interval are included in the notification of the registration area), or, · Based on the mapping between the geographical area and the tracking area and a list of one or more tracking areas forming the registration area (the mapping is read from storage and the list of one or more tracking areas is included in the notification of the registration area), Determine a second plurality of terrestrial cells currently mapped to the registration area. This method further includes step S2030 of sending a paging message for paging the UE within the second plurality of cells.

[0135] Also, corresponding to the AMF system disclosed above, provide a communication method for the AMF system. As shown in FIG. 21, this method for the AMF system includes step S2110 of receiving a registration request from a user equipment (UE), and the registration request includes · A notification of the first position of the UE, or, · The cell ID of the last cell visited by the UE and a timestamp indicating the first time at which the UE was located within the last cell, and includes.

[0136] This method for the AMF system includes generating a notification of a registration area including the first position of the UE. The notification of the registration area is · A list of cell IDs of a plurality of terrestrial mobile cells or cell sections of terrestrial mobile cells, and a notification of a second time when the plurality of terrestrial mobile cells form a registration area (the registration area is determined for each of the plurality of terrestrial mobile cells or cell sections based on coverage area information indicating the coverage area of the cell or cell section relative to the satellite position of the satellite generating the cell and the ephemeris data of the satellite), or, · A list of cell IDs and a notification of a time interval during which a plurality of terrestrial mobile cells or cell sections form a registration area, or, · A list of one or more tracking areas forming a registration area (the list of one or more tracking areas is determined based on a mapping between a geographical area and the tracking area, and the mapping is read from storage).

[0137] Furthermore, this method for the AMF includes sending a registration acceptance message including a notification of the registration area.

[0138] In the present disclosure, unless otherwise indicated in the context, any description and example are to be construed as applicable to each of the UE, the base station, and the AMF system, and are to be applied to both the apparatus and the method.

[0139] Stored Mapping between TAC and Geographic Area

[0140] In some embodiments, the mapping between the TAC and the geographical area is predefined as a fixed relationship and installed in the UE's memory. The memory can be a memory device, a SIM (Subscriber Identity Module), an embedded memory, or other memory devices. The UE determines its location, for example, using GNSS (Global Navigation Satellite System), derives the TAI based on its location information, and transmits the derived TAI to the AMF as a notification of its location. The UE then receives, in a registration acceptance message from the AMF, a list of one or more tracking areas (which can be indicated by the TAC) as a notification of the registration area. When the UE needs to determine whether it is still within the registration area at a certain location (the "second location") (for example, for periodic updates, or when camping or visiting a new cell), the UE circuit 1790 reads the mapping between the tracking area or TAC and the geographical area from storage. Thus, the UE may further include a storage interface for reading the mapping from storage. The UE determines whether it is within the registration area composed of the TAC(s) in the list based on the second location (specifically, the TAC formed based on the second location and thereby indicating the second location), the received list of TAC(s), and the stored mapping.

[0141] For example, in the mapping between the TAC and the geographical area, one TAC can be assigned to one country (for example, TAC1 = Germany, TAC2 = Austria, TAC3 = Switzerland, etc.). For a country with a larger area, multiple TACs can be defined and these can be assigned to states, federal states, etc. The boundaries of the geographical area can be stored in a storage device such as the UE or the SIM, or can be derivable from map information such as a digital map stored in the UE or the storage device. Thus, the UE can know in which area it is located based on the location measurement value.

[0142] Embodiments that use the stored mapping between the TAC and the geographical area provide backward compatibility in that one or more TACs can be used to signal the registration area to the UE as in the prior art. However, if the mapping is stored in a storage device such as the UE or the SIM, it may be difficult to update the TA definition (the mapping from one TAC to a specific area).

[0143] Cell Coverage Area by Time

[0144] In some embodiments, the registration area (or tracking area) is defined by the combination of the (terrestrial mobile) cell coverage areas at a particular time.

[0145] At this time, the cell coverage area can be defined by one of the following information, which can be included in the coverage area information for each of the plurality of terrestrial mobile cells and thus can be made available to the UE, as shown in FIGS. 22 to 24.

[0146] In the first example, as shown in FIG. 22, the cell area is defined by the satellite beam direction of each beam forming the cell (as described with reference to FIGS. 13 and 14, a cell can consist of one beam or include a plurality of beams) and the terrestrial beam radius or diameter, such as the radius or diameter of the cell or the beam footprint on the earth. In this case, the cells can overlap.

[0147] In the second example, as shown in FIG. 23, the cell area of the terrestrial mobile cell is defined by a polygon that defines the coverage area so as not to overlap. For example, the cell area is defined by the vertices of a non-overlapping shape such as a rectangle or a hexagon.

[0148] For example, a polygon can be indicated using a reference point (e.g., a corner or a center) that can be a relative position with respect to the current satellite position available from ephemeris data, and another indication of the length of the sides of the polygon or the size of the polygon. As another example, a polygon can be indicated using the coordinates of all the corners of the polygon relative to the satellite position.

[0149] In a third example shown in FIG. 24, a cell can be defined by a cell center and a coverage-in distance (e.g., a coverage-in radius) from the center. In this example, the signaling can be the same as in the first example.

[0150] The above definitions of the coverage area information according to the first to third options can be provided relative to the satellite position (e.g., the satellite position of the satellite (or satellites) generating the satellite beam(s)), which changes over time and can be derived from the ephemeris data for a given point in time. As the satellite moves over time, the coverage area, e.g., its size, can also change over time. For example, the size of the satellite beam area can be adjusted according to the UE density or population density of the area covered by the satellite beam. Thus, when the satellite is moving over a more populated area of the earth, the coverage area, such as the beam footprint or the terrestrial cell / beam area, can be reduced to provide smaller cells to cope with the increased demand caused by more UEs that need to be served.

[0151] A tracking area or a registration area is defined by a combination of cell areas associated with a timestamp, as shown in FIG. 25 (e.g., TA1 = {cell 1, cell 2, cell 3, cell 4, t = 13:01}, and TA2 = {cell 5, cell 6, cell 7, cell 8, t = 13:01}).

[0152] In the case of the definition of the cell coverage area of the mobile cells according to the above examples of FIGS. 22 to 24 associated with a given timestamp, the user equipment can calculate the area on the earth covered by these cells at the indicated time using the cell coverage area information, the timestamp, and the satellite ephemeris data. Then, the registration area and / or the tracking area can be determined as the area covered by a plurality of cells at a specific time. Therefore, the tracking area and / or the registration area can be considered to be defined by the "frozen cell" that covered or would cover the registration area at the indicated time.

[0153] For example, the UE receives the coverage area information within the system information. For example, the cell coverage area is signaled from the gNB to the UE via broadcast RRC signaling such as SIB. In addition to the cell coverage area, the UE may further receive the satellite ephemeris data or a part of the ephemeris data in the system information, and then the UE can use this (optionally using a further part of the ephemeris data that may have been previously stored in a storage device) to calculate the movement of the satellite relative to the earth's surface.

[0154] The registration area is signaled from the AMF to the UE via NAS signaling such as the registration acceptance message or the configuration update command message shown in FIGS. 6 and 7. At this time, it is sufficient to signal only the TAs in which the UE is registered to the UE. Specifically, these TAs can be signaled by signaling a "frozen cell", that is, a list of cell IDs and a timestamp of the time when the cells in the list form the registration area. For example, the registration area = {cell 1, cell 2, cell 3, cell 4, cell 5, cell 6, cell 7, cell 8, t = 13:01}, which corresponds to TAC1 and TAC2 in FIG. 25. These cell IDs can be signaled instead of the TA code, and the TA code is not required to determine the registration area in the UE. Nevertheless, the concept of the tracking area can still be used on the AMF or base station side. For example, the AMF may include a plurality of cells for forming the registration area assigned to the UE.

[0155] Therefore, the UE knows the mapping between the registration area and the geographical location. Based on this, the UE can determine whether it has exited the registration area from its own location information such as GNSS position measurements.

[0156] For example, to determine whether the UE is still within the registration area, the UE can test whether it is within each cell coverage area of the "frozen cells" that make up the registration area at a given time, for example, by comparing the distance from the UE to the cell center with the cell radius. When the UE identifies the coverage area of a frozen cell whose distance to the center is smaller than the radius, the UE knows that it is within the registration area and can stop the calculation. Alternatively, based on multiple cell coverage areas, the UE can calculate the range or boundary of the registration area and determine whether the UE is located within these boundaries for the entire registration area.

[0157] Cell coverage area information may further be preconfigured in both the AMF system and the gNB during the cell planning phase or, alternatively, may be signaled from the gNB to the AMF via NGAP signaling, e.g., an NG Setup Request message, or a RAN Setup Update message (see FIGS. 8 and 9). Further, the mapping between the cell and the gNB may be preconfigured in the AMF. The UE reports to the AMF via a Registration Request message, with a timestamp, the cell ID of the last visited cell, or, alternatively, reports a notification of the UE location.

[0158] Accordingly, the AMF knows which gNB(s) cover the registration area at any given time and can determine which gNB or gNB(s) should deliver paging messages.

[0159] Further, the definition of the tracking area and the registration area in the form of the cell ID and timestamp corresponding to the "frozen cell" is signaled from the AMF to the gNB, e.g., in a paging message. Accordingly, the gNB knows which cell(s) cover the registration area and can determine in which cell(s) to broadcast paging.

[0160] An example of a possible registration and paging call flow is shown in FIG. 26. As shown, the gNB transmits to the UE a System Information Block (SIB) containing cell coverage information including a notification of the cell coverage area relative to the satellite position. The SIB may further include a notification of satellite ephemeris data, except when the ephemeris data is fully stored on the UE side. Further, the gNB may transmit to the AMF the cell coverage area information included in the NG Setup Request message (e.g., when the cell coverage information is not preconfigured in the AMF as well).

[0161] At the initial registration time t, the UE sends a registration request message to the AMF that includes UE location information or includes the cell ID of the last visited cell together with a timestamp. In response, the AMF sends a registration acceptance message to the UE that includes, as a notification of the registration area, a list of cell IDs and a timestamp of the time when the cells indicated by the list form the registration area. As shown in FIG. 26, the registration request and the registration acceptance may be forwarded by the gNB.

[0162] At time t+1, while the UE is in the idle state, the AMF receives downlink data for the UE. Then, the AMF system determines the gNB(s) that are currently mapped to the registration area and that serve the cells currently mapped to the registration area. To these gNBs, the AMF system sends a paging message (or a paging request message) that includes a list of cells and a timestamp of the time when these cells form the registration area. Using the list, the timestamp, and the ephemeris data held by the gNB, the gNB determines which of the cells it serves are currently included in the registration area and performs paging of the UE across these cells included in the registration area.

[0163] Paging is initiated by the AMF when the UE is in the RRC idle mode. Thus, the AMF sends a paging message to the base station(s), and the base station broadcasts the paging message to the cells of the registration area to page the UE. In the present disclosure, the term "paging request" or "paging request message" is used for a message from the AMF to the base station that may include a notification of the registration area and may include a paging message for paging the UE.

[0164] At time t+2, the UE may detect that its position is outside the registered area based on the position measurement value. Then, the UE sends a new registration request including its current position and receives, in the registration acceptance message, a list of new cell IDs and a timestamp indicating that these cells form the UE's new registered area. Thereafter, the UE replaces the previous registered area with the new one.

[0165] If the cell coverage area information is in the SIB together with the ephemeris data, this data may further facilitate the UE to perform cell selection without measuring the radio signal strength, because otherwise, the radio signal strength may be frequently measured due to the movement of the cell. Therefore, the cell coverage area information can be used by the UE for cell selection and reselection, and to determine whether the UE is within the registered area.

[0166] Furthermore, if the cell coverage area is already available via the SIB, only a limited amount of signaling overhead (cell ID + timestamp) is required to indicate the registered area based on the cell coverage area information.

[0167] Cells with Their Respective Timings

[0168] In some embodiments, the registered area or tracking area is defined by listing all cells associated with the respective timing (or time interval) during which the cell covers a given geographical location or area on the Earth. As a notification of the registered area, the UE is provided with a list of cell IDs of the terrestrial mobile cells and a notification of the time interval during which the terrestrial mobile cells form the registered area.

[0169] In addition, the notification of the registered area included in the registration acceptance message from the AMF may include a list of a plurality of cell IDs of terrestrial mobile cells (or cell sections), and for each list of the plurality of cell ID lists, a plurality of time intervals indicating when the terrestrial mobile cells (or cell sections) respectively indicated by the cell ID list form the registered area.

[0170] Therefore, by notifying the UE of the cells within the registered area for a plurality of time intervals, it is not necessary to signal the registered area every time the cells constituting the registered area change.

[0171] FIG. 27 shows an example in which two tracking areas TA1 and TA2 change as follows within two time intervals of 13:01 to 13:10 and 13:11 to 13:20 (like the example in FIG. 25, this example is merely illustrative, and the present disclosure is not limited to any specific length of time interval or the number of cell IDs within the registered area or tracking area). · TA1 = {13:01 to 13:10 cells 1, 2, 3; 13:11 to 13:20 cells 2, 3, 4; ...} · TA2 = {13:01 to 13:10 cells 4, 5, 6; 13:11 to 13:20 cells 5, 6, 7; ...}

[0172] As can be seen from FIG. 27, the set of cells included in the TA remains the same during a certain period or time interval (10 minutes in the above example). Therefore, furthermore, because the cells are always moving, the resulting TA (and thus the registered area).

[0173] In an embodiment where one or more lists of such cell IDs and corresponding time intervals are signaled to the UE as a notification of the registration area, the tracking area code is not required on the UE side. Nevertheless, the tracking area can be used to determine the registration area to be assigned to the UE on the AMF side. The present disclosure is not limited to a specific method of how the tracking area is determined on the AMF side.

[0174] For example, considering the example of FIG. 27, a registration area {TA1; TA2} may be assigned to the UE.

[0175] Therefore, the UE may be shown the registration area in two subsequent time intervals as follows. RA = {13:01~13:10 Cell 1, Cell 2, Cell 3, Cell 4, Cell5, Cell 6; 13:11~13:20 Cell 2, Cell 3, Cell 4, Cell 5, Cell 6, Cell 7}

[0176] The registration area is signaled from the AMF to the UE in the form of a set of multiple cells (corresponding to a list of multiple cell IDs) associated with a timing (e.g., each time interval in which one of the sets of cells forms the registration area) via NAS signaling, e.g., a registration acceptance message or a configuration update command message.

[0177] There is no need to notify the UE of the coverage area of each cell. Legacy cell (re)selection based on radio signal strength can be reused. As a result, when the UE performs legacy cell (re)selection based on radio signal strength, the UE can determine whether it has exited the registration area without determining its location from the cell ID of the newly visited or camped cell and the timing of visiting that cell.

[0178] In addition, cell coverage area information can be pre-configured in the AMF (and optionally the gNB) during the cell planning phase, for example, based on the estimation of the cell coverage of terrestrial mobile cells. Also, the mapping between the cell and the gNB can be pre-configured in the AMF. Therefore, since the AMF knows which gNB(s) cover the registered area at any time or times, it can determine which gNB(s) should be sent the paging message.

[0179] Furthermore, the UE signals to the AMF in the registration request message the cell ID of the last visited cell and the timestamp (e.g., the timestamp of the signal strength measurement) when the UE was located within that cell.

[0180] Also, the registered area (and / or tracking area) is signaled to the gNB, for example, in a paging message (or a paging request including the paging message), in the form of a set of multiple cells (corresponding to a list of multiple cell IDs) associated with a timing (e.g., each time interval during which one of the sets of cells forms the registered area). As a result, the gNB knows which cell(s) cover the registered area and can determine which cell(s) to broadcast the paging to.

[0181] An exemplary registration and paging call flow is shown in FIG. 28. At time t, for example, when the initial registration of the UE is performed, the UE sends a registration request to the AMF indicating the last visited cell with a timestamp. Then, the UE receives a registration acceptance message from the AMF, which includes, as a notification of the registered area, a set of multiple cells (e.g., a list of multiple cell IDs) and an associated timing which is the timing during which one set of cells forms the registered area.

[0182] At time t+1, if the UE is paged by the core network, the AMF that has received the DL data for the UE determines the gNB(s) currently mapped to the registration area and sends a paging message (or a paging request message containing the paging message) including a set of a plurality of cells whose timing is associated as the registration area to these gNBs. In principle, it is sufficient for the gNB to simply receive the cell IDs of the cells served by each gNB. The gNB determines the cells currently mapped to the registration area and performs paging of the UE.

[0183] At time t+2, if the UE camps on a new cell outside the registration area, a registration request including the cell ID of the newly visited cell and a registration acceptance message including a new set of a plurality of cells indicating the new registration area are exchanged between the UE and the AMF in the same way as at the initial registration at time t.

[0184] If the registration area is shown to the UE as a plurality of lists of cell IDs of sets of cells and their associated timing that form the registration area, the UE does not need to be able to determine its own position and can reuse legacy cell selection based on radio strength. Nevertheless, instead of the cell ID and timestamp of the last visited cell, the UE may transmit location information in the registration request.

[0185] Furthermore, the TAC does not need to be broadcast by the mobile cell. Therefore, problems related to the broadcast of the TAC do not necessarily occur. Such problems may include variations in the TAC due to "hard switches" or overheads due to soft switches.

[0186] Geographic Zones and Radio Signal Coverage

[0187] In some embodiments, the TA and / or the registered area RA are defined by a cell area or a "restricted cell area" (corresponding to a cell section) associated with a timing, where the "restricted cell area" is defined by an intersection of a geographical zone and a radio signal coverage.

[0188] The geographical zones can be pre-installed in the UE (e.g., stored in a SIM or other memory device) and pre-defined in the network (gNB and core network). These geographical zones can be used, for example, to define the boundaries of an authorization area.

[0189] For example, a satellite beam can broadcast multiple cell IDs (the cell ID can correspond not only to a cell but also to a cell section or a "restricted cell area") associated with different cells belonging to different countries or authorization areas in some cases. In this case, when performing cell (re)-selection using signal strength, the UE may receive the same signal strength from multiple cells or cell sections because they are generated by the same satellite beam. However, the sections corresponding to multiple cells or "restricted cell areas" can be associated with different authorization areas. For example, the satellite beam moves across the earth along the border of two countries and broadcasts two cell IDs of the two countries respectively. In the present disclosure, the "restricted cell ID", which can have its own cell ID, refers to a cell section of a cell within one of the pre-defined geographical areas. The UE then selects the cell with the strongest radio strength that is permitted (or authorized) at a given location.

[0190] For example, if the UE determines that it is not located within the registered area (e.g., by location measurement or by comparing the cell ID (or signal strength from multiple cell IDs) of a newly camped or visited cell with a list of cell IDs that define the previous registered area at a given time interval), the UE performs signal strength measurements for cell (re)selection and may receive the same or similar signal strengths from multiple cells, and thus these are candidates for the newly visited cell.

[0191] Next, the UE may determine the geographical area in which the UE is located from the stored or pre-installed geographical areas based on the location measurement value and the definition of the geographical area that can be read from storage or memory.

[0192] Next, the UE selects one of the candidates included in the geographical area in which the UE is located as the newly visited cell or cell section. This selection is performed based on the association between each cell ID among the multiple candidates and one of the stored geographical areas.

[0193] This association between the cell ID and the geographical area (e.g., the mapping between the cell ID and the geographical zone information) may be signaled to the UE cell by cell from the gNB within the system information (e.g., SIB) received by the UE.

[0194] Also, for example, if the list of cell IDs indicated by the AMF exceeds the restricted geographical area, the installed or stored geographical area may be used by the UE to determine which of the cells included in the list of cell IDs or the list of multiple cell IDs are present within the geographical area. Next, the UE circuit 1790 may determine the registered area formed by the cell or cell section from the list(s) of cell IDs associated with the geographical area in which the UE is located.

[0195] An example of a plurality of cell sections or "restricted cell areas" divided into different geographical areas or zones is shown in FIG. 29. At this time, it can be assumed that one satellite beam transmits a plurality of (for example, two or more) cell IDs. For example, beam 1 covers both cell 1 and cell 2. Since both cells or restricted cell areas are within the same radio coverage, the UE detects similar (for example, substantially the same) radio signal strengths from both cells associated with the same radio satellite beam. The UE may select a restricted cell area (RCA: restricted cell area) 1 or RCA2 based on location information regarding whether the UE is located in zone A or zone B, where RCA1 = common part {cell 1, zone A}, and RCA2 = common part {cell 2, zone B}. Different tracking areas or registration areas can be indicated by signaling a list of a plurality of cell IDs (or RCA IDs or cell section IDs) and the associated timing or time interval. · TA1 (or RA1) = {13:01~13:10 RCA1, RCA3, RCA5; 13:11~13:20 RCA3, RCA5, RCA7}; · TA2 (or RA2) = {13:01~13:10 RCA2, RCA4, RCA6; 13:11~13:20 RCA4, RCA6, RCA8}

[0196] As described above, the definition of a geographical zone or area can be stored or installed in the UE or a memory device. Further, the association between the cell ID (or RCA ID) and the geographical zone can be broadcast by the gNB, for example, via the SIB. The registration area in the form of a set of a plurality of cells associated with timing is signaled from the AMF to the UE via NAS signaling (for example, a registration acceptance message) in the same manner as the above description of the embodiment entitled "cells with respective timings".

[0197] As a result, the UE can perform cell (re)selection based on both location information and radio wave intensity, and can determine whether the UE has left the registered area from the cell ID and timing of camping.

[0198] The manner of signaling to the AMF system and the gNB can be the same as the above description in the section "Cells with respective timings". Cell coverage area information (including mapping to the gNB) can be set or pre-set in the AMF (and gNB) during the cell planning phase. The UE signals to the AMF in the registration request message either the last visited cell with a timestamp or the location information. Also, the definition of the TA and / or the registered area is signaled to the gNB in the form of a set of a plurality of cells associated with timings (a list of cell IDs / RCA IDs), for example, in a paging message or a paging request message including the paging message sent to the UE.

[0199] As a result, the AMF knows which gNBs cover the registered area at any given time and can determine which gNBs need to be delivered the paging message (or paging request message). Also, since the gNB knows which cells (multiple possible) cover the registered area, it can determine which cells should broadcast the paging.

[0200] The registration and paging call flows among the UE, gNB, and AMF are shown in FIG. 30. As described above, the UE receives the SIB sent from the gNB, which includes the mapping between the cell ID (RCA ID) and the zone information. Further, although the UE is shown to send location information in the registration request (steps 1 and 6), the UE may also send the cell ID and the associated timing. Also, at timing t+2, the UE camps on a new cell outside the registration area, which is selected or determined based on the radio strength and the UE location (e.g., to determine in which zone or geographical area the UE is located). The further flows shown in FIG. 30 are the same as the above description of the flow shown in FIG. 28.

[0201] As described in this section, the cell accessibility is controlled using additional location information in addition to the received signal strength. When multiple cells or cell sections are transmitted by the same satellite, by thus additionally using location information to control the cell accessibility, the reduction of the number of cells within the registration area can be promoted, and the paging overhead can be reduced.

[0202] As described above, the UE may perform cell (re)selection, e.g., selection of newly visited cells inside and outside the registration area, based on either location information (e.g., location measurements such as GNSS) or signal strength measurements. For example, when location information is used to determine whether the UE is still within the registration area, the cell selection may also be location-based, which can promote the reduction of signal strength measurements. On the other hand, the determination of whether the UE is within the registration area using the signal strength may be practical for UEs where positioning is impossible or the positioning function is turned off.

[0203] Further, as shown in FIGS. 26, 28, and 30, when the circuit determines that the UE is not located within the registration area, the circuit transmits a registration request including at least one of a notification of the UE's location, or the cell ID of the newly visited cell and a timestamp indicating the time when the UE is located within the newly visited cell (e.g., when the signal strength was measured).

[0204] On the other hand, when the UE is within the registration area and DL data for the UE is available, the UE receives paging (e.g., one or both of paging DCI and a paging message) transmitted by the gNB (or gNBs) within the registration area.

[0205] One or more base stations (e.g., gNBs) that perform paging of the UE are determined by the AMF system. Specifically, in some embodiments, the AMF determines the base stations currently mapped to the registration area (which has already been indicated to the UE via registration acceptance) and transmits a paging request message to one or more base stations. The paging request message includes · a list of cell IDs of a plurality of terrestrial cells or cell sections, and a notification of a second time, or · a list of cell IDs, and a notification of the time interval during which a plurality of terrestrial cells or cell sections form the registration area, or · a list of tracking areas that form the registration area, and the like.

[0206] For example, the paging request message may further include a paging message.

[0207] As described above, it can be seen from the embodiments of the present disclosure that it is not necessary to broadcast the TA code (TAC: TA code) in the cell system information in order to enable the UE to indicate the registration area. Therefore, problems related to moving tracking areas, such as those related to "hard switches" and "soft switches", can be reduced or avoided. Specifically, in the embodiments described with reference to FIGS. 22 to 30, the TA code may not be required at all.

[0208] Also, each of the above-described embodiments shown in FIGS. 22 to 30 includes timing information (e.g., the time when a "frozen" cell is defined, or the time interval during which each cell covers the registration area) for defining the tracking area and the registration area. Such timing information enables the movement of the cell to be recognized by the gNB and the core network in a predictable manner. Further, in the embodiments described in the section entitled "Cell Coverage Area over Time", ephemeris data is also available at the UE, and the UE can use this for the determination of the registration area and, in some cases, for cell (re)-selection.

[0209] As described above, the examples and embodiments of the present disclosure have been presented using registration area management for RRC idle UEs as an example. However, the present disclosure can also be applied to RAN notification area (RNA: RAN Notification Area) management for inactive UEs. The RAN notification area is the basis for device tracking at the RAN level. Updates to the RAN notification area are managed by RRC RAN notification area updates sent from the UE to the gNB. Since a change in the tracking area implies a change in the RNA, an RRC RAN notification area update is implicitly executed every time the UE performs a registration update as described above.

[0210] The present disclosure can be implemented by software, hardware, or software that cooperates with hardware. Each functional block used in the description of each of the above embodiments can be partially or fully implemented by LSI (Large Scale Integration) such as an integrated circuit (IC), and each process described in each embodiment can be partially or fully controlled by the same LSI or a combination of LSIs. The LSI can be individually formed as a chip, or one chip can be formed to include part or all of the functional blocks. The LSI can include data inputs and outputs coupled thereto. In this specification, the LSI can be called an IC, a system LSI, a super LSI, or an ultra LSI depending on the degree of integration. However, the technology for implementing the integrated circuit is not limited to the LSI and can be realized using an application specific circuit, a general-purpose processor, or a dedicated processor. Also, an FPGA (Field Programmable Gate Array) that can be programmed after the manufacture of the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells arranged in the LSI can be used. The present disclosure can be realized as digital processing or analog processing. If future integrated circuit technology replaces the LSI as a result of the progress of semiconductor technology or other derivative technologies, the functional blocks can be integrated using the future integrated circuit technology. Biotechnology can also be applied.

[0211] The present disclosure can be implemented by any type of device, apparatus, or system having a communication function, referred to as a communication device.

[0212] The communication device can include a transceiver and a processing / control circuit. The transceiver can include and / or function as a receiver and a transmitter. The transceiver as a transmitter and a receiver can include an RF (radio frequency) module including an amplifier, an RF modulator / demodulator, etc., and one or more antennas.

[0213] Some non-limiting examples of such communication devices include telephones (e.g., cellular (cell) phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine (remote health and medicine) devices, and vehicles that provide communication capabilities (e.g., automobiles, airplanes, ships), as well as various combinations thereof.

[0214] The communication device is not limited to being portable or mobile and can include any type of non-portable or stationary device, apparatus, or system, such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines, and any other "things" within the network of the "Internet of Things (IoT)".

[0215] Communication can include data exchange via, for example, cellular systems, wireless LAN systems, satellite systems, etc., and various combinations thereof.

[0216] The communication device can include devices such as a controller or sensor coupled to a communication device that performs the communication functions described in this disclosure. For example, the communication device can include a controller or sensor that generates control signals or data signals used by a communication device that performs the communication functions of the communication device.

[0217] The communication device can also include infrastructure facilities such as base stations, access points, and any other device, apparatus, or system that communicates with or controls a device as in the above non-limiting examples.

[0218] In summary, in the first embodiment, a user equipment (UE) transmits a registration request during operation, and the registration request includes · notification of a first position of the UE, or · a cell ID of the last cell visited by the UE and a timestamp indicating a first time when the UE was located within the last cell, receives a registration acceptance message including notification of a registration area, where the registration area includes the first position of the UE, and a transceiver that, during operation, · based on a list of cell IDs of a plurality of terrestrial cells or cell sections of the terrestrial cells, notification of a second time when the plurality of terrestrial cells form the registration area, for each of the plurality of terrestrial cells, coverage area information indicating a coverage area of the cell or cell section relative to a satellite position of a satellite that generates the cell and ephemeris data of the satellite, and a measurement value of a second position of the UE, where the list of the plurality of terrestrial cells and the notification of the second time are included in the notification of the registration area, or · based on a list of the cell IDs, notification of a time interval during which the plurality of terrestrial cells or cell sections form the registration area, including the second position of the UE, and a cell ID of a newly visited cell or cell section different from the last cell, where the list of the cell IDs and the notification of the time interval are included in the notification of the registration area, or · based on the measurement value of the second position, a mapping between a geographical area and a tracking area, and a list of one or more tracking areas forming the registration area, where the mapping is read from storage and the list of the one or more tracking areas is included in the notification of the registration area, A user equipment is provided that includes a circuit that determines whether the UE is located within the registration area at the second position.

[0219] In the second embodiment, in addition to the first embodiment, when operating, the transceiver receives the coverage area information within the system information.

[0220] In the third embodiment, in addition to the first or second embodiment, for each of the plurality of terrestrial cells, the coverage area information · includes the satellite beam direction of each beam forming the cell and the radius or diameter of the coverage area, or · includes a polygon that defines the coverage area so as not to overlap, or · includes the center and radius of the coverage area. is included.

[0221] In the fourth embodiment, in addition to the first embodiment, the notification of the registration area includes a list of cell IDs of terrestrial cells or cell sections of terrestrial cells including the list of cell IDs, and for each of the lists of the plurality of cell IDs, a plurality of notifications of time intervals including the time intervals respectively indicating the time intervals during which the terrestrial cells or cell sections respectively indicated by the list of cell IDs form the registration area.

[0222] In the fifth embodiment, in addition to the first or fourth embodiment, when the circuit determines that the UE is not located within the registration area at the second position and the received signal strengths of a plurality of candidates of the newly visited cell or cell section are substantially the same, when operating, the circuit determines the geographical area where the UE is located from among the geographical areas based on the measurement value at the second position and the definition of the geographical area read from the storage, and selects, as the newly visited cell or cell section, a candidate included in the geographical area where the UE is located based on the association between each cell ID among the plurality of candidates included in the system information and one of the geographical areas.

[0223] In the sixth embodiment, in addition to any of the first to fifth embodiments, when operating, the circuit selects the newly accessed cell based on the second position.

[0224] In the seventh embodiment, in addition to the first, fourth, or fifth embodiment, when operating, the circuit selects the newly accessed cell based on the signal strength measurement value.

[0225] In the eighth embodiment, in addition to any of the first to seventh embodiments, when operating, the transceiver receives a paging message within the registered area.

[0226] In the ninth embodiment, in addition to any of the first to eighth embodiments, when the circuit determines that the UE is not located within the registered area at the second position, when operating, the transceiver transmits a second registration request, and the second registration request includes · notification of the second position of the UE, or · the cell ID of the newly accessed cell and a timestamp indicating the third time when the UE was located within the newly accessed cell, including at least one of the above.

[0227] In the tenth embodiment, a base station, when operating, an interface that receives a paging request message for paging a user equipment (UE) including notification of a registered area, and when operating, · a list of cell IDs of a first plurality of terrestrial mobile cells or cell sections of the terrestrial mobile cells, notification of a second time when the first plurality of terrestrial mobile cells form the registered area, and for each of the first plurality of terrestrial mobile cells, based on coverage area information indicating the coverage area of the cell or cell section relative to the satellite position of the satellite generating the cell and the ephemeris data of the satellite, where the list of the first plurality of terrestrial mobile cells and the notification of the time are included in the notification of the registered area, or · Based on the list of the cell IDs and the notification of the time interval during which the first plurality of terrestrial cells or cell sections form the registration area, where the list of the cell IDs and the notification of the time interval are included in the notification of the registration area, or · Based on the mapping between the geographical area and the tracking area and the list of one or more tracking areas that form the registration area, where the mapping is read from storage and the list of the one or more tracking areas is included in the notification of the registration area A base station is provided that includes a circuit for determining a second plurality of terrestrial cells currently mapped to the registration area, and a transceiver that, in operation, transmits a paging message for paging the UE within the second plurality of cells.

[0228] In an eleventh embodiment, an access and mobility management function (AMF) system, which, in operation, is an interface for receiving a registration request of a user equipment (UE), where the registration request · Notification of a first position of the UE, or · The cell ID of the last cell visited by the UE and a timestamp indicating a first time when the UE was located within the last cell The interface including the above, and a circuit that, in operation, generates a notification of a registration area including the first position of the UE, where the notification of the registration area · Includes a list of cell IDs of a plurality of terrestrial cells or cell sections of the terrestrial cells and a notification of a second time when the plurality of terrestrial cells form the registration area, where the registration area is determined for each of the plurality of terrestrial cells or cell sections based on coverage area information indicating a coverage area of the cell or cell section relative to the satellite position of the satellite that generates the cell and ephemeris data of the satellite, or · including a list of the cell IDs and a notification of a time interval during which the plurality of terrestrial cells or cell sections form the registration area, or, · including a list of one or more tracking areas that form the registration area, wherein the list of the one or more tracking areas is determined based on a mapping between a geographical area and the tracking area, and the mapping is read from storage, An AMF system is provided, comprising the circuit, wherein the interface, during operation, transmits a registration acceptance message including the notification of the registration area.

[0229] In a twelfth embodiment, in addition to the eleventh embodiment, the circuit, during operation, determines one or more base stations currently mapped to the registration area, and the interface, during operation, transmits a paging request message to the one or more base stations, and the paging request message · a list of the cell IDs of the plurality of terrestrial cells or cell sections and the notification of the second time, or, · the list of the cell IDs, and the notification of the time interval during which the plurality of terrestrial cells or cell sections form the registration area, or, · the list of the tracking areas that form the registration area, including.

[0230] In a thirteenth embodiment, a communication method for a user equipment (UE), comprising the step of transmitting a registration request, wherein the registration request · notifying a first position of the UE, or, · the cell ID of the last cell visited by the UE and a timestamp indicating a first time when the UE was located within the last cell, including at least one of; the step of receiving a registration acceptance message including a notification of a registration area, wherein the registration area includes the first position of the UE; and the step of determining, · A list of cell IDs of a plurality of terrestrial mobile cells or cell sections of the terrestrial mobile cells, a notification of a second time at which the plurality of terrestrial mobile cells form the registration area, for each of the plurality of terrestrial mobile cells, coverage area information indicating a coverage area of the cell or cell section relative to a satellite position of a satellite that generates the cell, ephemeris data of the satellite, and a measurement value of a second position of the UE, wherein the list of the plurality of terrestrial mobile cells and the notification of the second time are included in the notification of the registration area, or, · Based on the list of the cell IDs, a notification of a time interval during which the plurality of terrestrial mobile cells or cell sections form the registration area, the second position of the UE, and a cell ID of a newly visited cell or cell section different from the last cell, wherein the list of the cell IDs and the notification of the time interval are included in the notification of the registration area, or, · Based on the measurement value of the second position, a mapping between a geographical area and a tracking area, and a list of one or more tracking areas that form the registration area, wherein the mapping is read from storage and the list of the one or more tracking areas is included in the notification of the registration area, Determining whether the UE is located within the registration area at the second position, and a communication method including the above steps is provided.

[0231] In a fourteenth embodiment, a communication method for a base station includes receiving a paging request message for paging a user equipment (UE) including a notification of a registration area, and a determining step, · A list of cell IDs of the first plurality of terrestrial cells or cell sections of the terrestrial cell, a notification of a second time at which the first plurality of terrestrial cells form the registration area, and for each of the first plurality of terrestrial cells, based on coverage area information indicating a coverage area of the cell or cell section relative to a satellite position of a satellite that generates the cell and ephemeris data of the satellite, wherein the list of the first plurality of terrestrial cells and the notification of the time are included in the notification of the registration area, or, · Based on the list of the cell IDs and a notification of a time interval during which the first plurality of terrestrial cells or cell sections form the registration area, wherein the list of the cell IDs and the notification of the time interval are included in the notification of the registration area, or, · Based on a mapping between a geographical area and a tracking area and a list of one or more tracking areas that form the registration area, wherein the mapping is read from storage and the list of the one or more tracking areas is included in the notification of the registration area, Determining a second plurality of terrestrial cells currently mapped to the registration area; and transmitting a paging message for paging the UE within the second plurality of cells. A communication method is provided.

[0232] In a 15th embodiment, a communication method for an access mobility function (AMF) system, the method comprising receiving a registration request of a user equipment (UE), the registration request comprising · A notification of a first position of the UE, or, · A cell ID of a last cell visited by the UE and a timestamp indicating a first time at which the UE was located within the last cell, Generating a notification of a registration area including the first position of the UE, the notification of the registration area comprising · A list of cell IDs of a plurality of terrestrial mobile cells or cell sections of the terrestrial mobile cells, and a notification of a second time when the plurality of terrestrial mobile cells form the registration area, where the registration area is determined for each of the plurality of terrestrial mobile cells or cell sections based on coverage area information indicating a coverage area of the cell or cell section relative to a satellite position of a satellite that generates the cell and ephemeris data of the satellite, or, · The list of cell IDs and a notification of a time interval during which the plurality of terrestrial mobile cells or cell sections form the registration area, or, · A list of one or more tracking areas that form the registration area, where the list of one or more tracking areas is determined based on a mapping between a geographical area and the tracking area, and the mapping is read from storage, steps, and a step of transmitting a registration acceptance message including the notification of the registration area. A communication method is provided.

[0233] It should be noted that the second to ninth embodiments are applicable in a form corresponding to the base station of the tenth embodiment and the AMF system of the eleventh embodiment, and the twelfth embodiment is applicable in a form corresponding to the base station of the tenth embodiment. Also, the steps executed during operation by a circuit, the steps executed during operation by a transceiver, and the steps executed during operation by an interface mentioned in the above embodiments of the UE, base station, and AMF correspond to the respective methods.

[0234] Also, a non-transitory medium is provided that stores program instructions for causing a processing circuit, such as a general-purpose processor, to execute all steps of the above method embodiments when executed.

[0235] Furthermore, there is provided an integrated circuit for a communication device, such as a UE, a base station, or an AMF system, that controls the communication device to execute all steps of the above-described method embodiments.

[0236] In summary, there is provided a user equipment (UE), a base station, an AMF (Access and Mobility Management Function) system, and a corresponding method. The UE is indicated to the UE by the AMF based on a combination of a signal strength measurement or a location and either a list of cell IDs of terrestrial cells and a stored mapping between timings or geographical areas and tracking areas, and determines whether the UE is located in a registration area where the UE is paged by the base station.

Claims

1. A user equipment (UE), comprising: a transceiver that transmits a registration request and receives a registration acceptance message including a list of one or more tracking areas that form a registration area, wherein the registration request includes a notification of a first position of the UE, the list of the one or more tracking areas includes the notification of the first position of the UE, and the notification of the first position is held by the UE; and a circuit that determines whether the UE is located within the registration area at the second position based on a notification of a second position of the UE and the list of the one or more tracking areas corresponding to a geographical area, wherein the tracking area corresponds to a cell ID of a plurality of terrestrial mobile cells associated with a time interval for forming the registration area; The user equipment is provided with.

2. The registration request includes a cell ID of the last cell visited by the UE and a timestamp indicating a first time when the UE was located within the last cell; The circuit - based on a list of cell IDs of a plurality of terrestrial mobile cells or cell sections of the terrestrial mobile cells, a notification of a second time when the plurality of terrestrial mobile cells form the registration area, coverage area information indicating a coverage area of the cell or cell section relative to a satellite position of a satellite that generates the cell, ephemeris data of the satellite, and a measurement of the second position of the UE for each of the plurality of terrestrial mobile cells, wherein the list of the plurality of terrestrial mobile cells and the notification of the second time are included in the notification of the registration area, or - based on the measurement of the second position of the UE, a mapping between a geographical area and a tracking area, and the list of the one or more tracking areas that form the registration area, wherein the mapping is read from storage, determines whether the UE is located within the registration area at the second position; The user equipment according to Claim 1.

3. The user equipment according to Claim 2, wherein the transceiver receives the coverage area information in system information during operation.

4. The coverage area information is for each of the plurality of terrestrial mobile cells, ・ The satellite beam direction of each beam forming the cell, and the radius or diameter of the coverage area, or, ・ A polygon that defines the coverage areas so as not to overlap, or, ・ The center and radius of the coverage area, The user equipment according to claim 2, comprising.

5. The notification of the registration area is A list of cell IDs of a plurality of terrestrial mobile cells or cell sections of terrestrial mobile cells including the list of the cell IDs, and For each of the lists of the plurality of cell IDs, a plurality of notifications of time intervals including the time intervals respectively indicating the time intervals during which the terrestrial mobile cells or cell sections respectively indicated by the list of the cell IDs form the registration area, The user equipment according to claim 2, comprising.

6. When the circuit determines that the UE is not located within the registration area at the second position, and the received signal strengths of a plurality of candidates of a newly visited cell or cell section different from the last cell are substantially the same, during operation, the circuit Determines the geographical area in which the UE is located from among the geographical areas based on the measurement value at the second position and the definition of the geographical area read from the storage, Based on the association between each cell ID of the plurality of candidates included in the system information and one of the geographical areas, selects a candidate included in the geographical area in which the UE is located as the newly visited cell or cell section, The user equipment according to claim 2.

7. During operation, the circuit selects a newly visited cell different from the last cell based on the second position, the user equipment according to claim 2.

8. During operation, the circuit selects a newly visited cell different from the last cell based on the signal strength measurement value, the user equipment according to claim 2.

9. During operation, the transceiver receives a paging message within the registration area, the user equipment according to claim 2.

10. When the circuit determines that the UE is not located within the registration area at the second position, during operation, the transceiver transmits a second registration request, and the second registration request is ・ Notification of the second position of the UE, or, ・The cell ID of a newly visited cell different from the last cell, and a timestamp indicating a third time when the UE was located within the newly visited cell The user equipment according to claim 2, comprising at least one of the above.

11. A communication method for a user equipment (UE), comprising: Sending a registration request, the registration request including a notification of a first position of the UE; Receiving a registration acceptance message including a list of one or more tracking areas forming a registration area, the one or more tracking areas including a notification of the first position of the UE, the notification of the first position being held by the UE; Determining whether the UE is located within the registration area at the second position based on a notification of a second position of the UE and the list of the one or more tracking areas corresponding to a geographical area, the tracking area corresponding to cell IDs of a plurality of terrestrial mobile cells associated with a time interval forming the registration area; A communication method comprising the above.

12. An integrated circuit for controlling processing of a user equipment (UE), the processing comprising: Sending a registration request, the registration request including a notification of a first position of the UE; Receiving a registration acceptance message including a list of one or more tracking areas forming a registration area, the one or more tracking areas including a notification of the first position of the UE, the notification of the first position being held by the UE; Determining whether the UE is located within the registration area at the second position based on a notification of a second position of the UE and the list of the one or more tracking areas corresponding to a geographical area, the tracking area corresponding to cell IDs of a plurality of terrestrial mobile cells associated with a time interval forming the registration area; An integrated circuit comprising the above.

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