Terminal devices and communication systems

Abstract

Enables rapid network connectivity. [Solution] The terminal device has multiple SIMs (Subscriber Identity Modules) and is configured to connect to multiple networks using the multiple SIMs. The multiple networks include a first network including an AMF (Access and Mobility Management Function) and a second network, and the terminal device is configured to receive information from the AMF related to avoiding paging collisions between the multiple networks.

Description

Technical Field

[0001] This disclosure relates to wireless communication technology.

Background Art

[0002] In the 3GPP (3rd Generation Partnership Project), which is a standardization organization for mobile communication systems, the radio section is called Long Term Evolution (LTE), and a communication method called System Architecture Evolution (SAE) is being studied for the overall system configuration including the core network and the radio access network (hereinafter collectively referred to as the network) (for example, Non-Patent Documents 1 to 5). This communication method is also called the 3.9G (3.9 Generation) system.

[0003] As the access method of LTE, OFDM (Orthogonal Frequency Division Multiplexing) is used in the downlink direction, and SC-FDMA (Single Carrier Frequency Division Multiple Access) is used in the uplink direction. Also, different from W-CDMA (Wideband Code Division Multiple Access), LTE does not include circuit switching and is only a packet communication method.

[0004] The decisions made by 3GPP regarding the frame structure in LTE systems, as described in Non-Patent Document 1 (Chapter 5), will be explained using Figure 1. Figure 1 is an explanatory diagram showing the structure of a radio frame used in an LTE communication system. In Figure 1, one radio frame is 10ms. A radio frame is divided into 10 subframes of equal size. Each subframe is divided into two slots of equal size. Downlink synchronization signals are included in the 1st and 6th subframes of each radio frame. The synchronization signals consist of a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS).

[0005] The 3GPP's decisions regarding channel configuration in LTE systems are described in Non-Patent Document 1 (Chapter 5). It is assumed that the same channel configuration as non-CSG cells will be used in CSG (Closed Subscriber Group) cells.

[0006] The Physical Broadcast Channel (PBCH) is a channel used for downlink transmission from base station equipment (hereinafter sometimes simply referred to as "base station") to communication terminal equipment (hereinafter sometimes simply referred to as "mobile terminal") and other such devices. A PBCH transport block is mapped to four subframes within a 40ms interval. There is no explicit signaling at 40ms timing.

[0007] The Physical Control Format Indicator Channel (PCFICH) is a channel used for downlink transmission from the base station to the communication terminal. The PCFICH notifies the communication terminal of the number of OFDM (Orthogonal Frequency Division Multiplexing) symbols to be used for PDCCHs. The PCFICH is transmitted for each subframe.

[0008] The Physical Downlink Control Channel (PDCCH) is the channel used for downlink transmission from the base station to the communication terminal. The PDCCH notifies resource allocation information for the Downlink Shared Channel (DL-SCH), one of the transport channels described later, resource allocation information for the Paging Channel (PCH), another transport channel described later, and HARQ (Hybrid Automatic Repeat reQuest) information related to the DL-SCH. The PDCCH carries the Uplink Scheduling Grant. The PDCCH also carries Ack (Acknowledgement) / Nack (Negative Acknowledgement), which are response signals to uplink transmissions. The PDCCH is also called the L1 / L2 control signal.

[0009] The Physical Downlink Shared Channel (PDSCH) is a channel used for downlink transmission from a base station to a communication terminal. The PDSCH is mapped to the Downlink Shared Channel (DL-SCH), which is a transport channel, and the PCH, which is also a transport channel.

[0010] A physical multicast channel (PMCH) is a channel used for downlink transmission from a base station to a communication terminal. A multicast channel (MCH), which is a transport channel, is mapped to the PMCH.

[0011] The Physical Uplink Control Channel (PUCCH) is the channel used for uplink transmission from the communication terminal to the base station. The PUCCH carries the Ack / Nack response signal for downlink transmission. The PUCCH also carries Channel State Information (CSI). The CSI consists of the Rank Indicator (RI), Precoding Matrix Indicator (PMI), and Channel Quality Indicator (CQI) report. RI is the rank information of the channel matrix in MIMO. PMI is information of the precoding weight matrix used in MIMO. CQI is quality information indicating the quality of the received data or the quality of the communication channel. The PUCCH also carries a Scheduling Request (SR).

[0012] The Physical Uplink Shared Channel (PUSCH) is a channel used for uplink transmission from a communication terminal to a base station. The Uplink Shared Channel (UL-SCH), which is one of the transport channels, is mapped to the PUSCH.

[0013] The Physical Hybrid ARQ Indicator Channel (PHICH) is the channel used for downlink transmission from the base station to the communication terminal. PHICH carries the Ack / Nack, which is the response signal to uplink transmissions. The Physical Random Access Channel (PRACH) is the channel used for uplink transmission from the communication terminal to the base station. PRACH carries the random access preamble.

[0014] The downlink reference signal (RS) is a well-known symbol in LTE communication systems. Five types of downlink reference signals are defined: Cell-specific Reference Signal (CRS), MBSFN Reference Signal, UE-specific Reference Signal (UE-specific), Demodulation Reference Signal (DM-RS), Positioning Reference Signal (PRS), and Channel State Information Reference Signal (CSI-RS). One measurement of the physical layer of a communication terminal is the Reference Signal Received Power (RSRP).

[0015] Similarly, the uplink reference signals are also known symbols for LTE communication systems. Two types of uplink reference signals are defined: the Demodulation Reference Signal (DM-RS) and the Sounding Reference Signal (SRS).

[0016] This section explains the transport channel described in Non-Patent Document 1 (Chapter 5). Of the downlink transport channels, the Broadcast Channel (BCH) broadcasts to the entire coverage of the base station (cell). The BCH is mapped to the Physical Broadcast Channel (PBCH).

[0017] Downlink Shared Channels (DL-SCH) are subject to retransmission control using HARQ (Hybrid ARQ). DL-SCH can broadcast to the entire coverage of a base station (cell). DL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also called persistent scheduling. DL-SCH supports discontinuous reception (DRX) for communication terminals to reduce power consumption. DL-SCH is mapped to Physical Downlink Shared Channels (PDSCH).

[0018] Paging Channels (PCHs) support DRX for communication terminals to enable low power consumption for those terminals. PCHs are required to broadcast across the entire coverage of a base station (cell). PCHs are mapped to physical resources, such as Physical Downlink Shared Channels (PDSCHs), which are dynamically available for traffic.

[0019] Multicast channels (MCHs) are used for broadcasting across the entire coverage of a base station (cell). MCHs support SFN synthesis of MBMS (Multimedia Broadcast Multicast Service) services (MTCH and MCCH) in multi-cell transmission. MCHs support quasi-static resource allocation. MCHs are mapped to PMCHs.

[0020] Among the uplink transport channels, the Uplink Shared Channel (UL-SCH) is subject to retransmission control using HARQ (Hybrid ARQ). UL-SCH supports dynamic or semi-static resource allocation. UL-SCH is mapped to the Physical Uplink Shared Channel (PUSCH).

[0021] Random Access Channels (RACHs) are limited to control information. RACHs carry a risk of collisions. RACHs are mapped to Physical Random Access Channels (PRACHs).

[0022] This section explains HARQ. HARQ is a technology that improves the communication quality of a transmission path by combining Automatic Repeat reQuest (ARQ) and Forward Error Correction. HARQ has the advantage that error correction works effectively through retransmission even on transmission paths where the communication quality changes. In particular, it is possible to achieve further quality improvement by combining the reception results of the initial transmission and the retransmission during retransmission.

[0023] Here is an example of how to retransmit data. If the receiving side is unable to correctly decode the received data, in other words, if a CRC (Cyclic Redundancy Check) error occurs (CRC=NG), the receiving side sends "Nack" to the sending side. Upon receiving "Nack," the sending side retransmits the data. If the receiving side is able to correctly decode the received data, in other words, if no CRC error occurs (CRC=OK), the receiving side sends "Ack" to the sending side. Upon receiving "Ack," the sending side sends the next data.

[0024] This section explains the logical channel described in Non-Patent Document 1 (Chapter 6). The Broadcast Control Channel (BCCH) is a downstream channel for broadcast system control information. The BCCH, being a logical channel, is mapped to the broadcast channel (BCH), which is a transport channel, or to the downstream shared channel (DL-SCH).

[0025] The Paging Control Channel (PCCH) is a downlink channel used to transmit changes to paging information and system information. The PCCH is used when the network does not know the cell location of a communication terminal. As a logical channel, the PCCH is mapped to the Paging Channel (PCH), which is a transport channel.

[0026] The Common Control Channel (CCCH) is a channel for transmit control information between a communication terminal and a base station. The CCCH is used when a communication terminal does not have an RRC connection with the network. In the downlink direction, the CCCH is mapped to the downlink common channel (DL-SCH), which is a transport channel. In the uplink direction, the CCCH is mapped to the uplink common channel (UL-SCH), which is a transport channel.

[0027] A Multicast Control Channel (MCCH) is a downlink channel for one-to-many transmission. MCCHs are used to transmit MBMS control information for one or more MCCHs from the network to communication terminals. MCCHs are only used by communication terminals receiving MBMS. MCCHs are mapped to the Multicast Channel (MCH), which is the transport channel.

[0028] The Dedicated Control Channel (DCCH) is a channel that transmits dedicated control information between a communication terminal and a network on a one-to-one basis. The DCCH is used when the communication terminal is in an RRC connection. The DCCH is mapped to the UL-SCH in the uplink and to the DL-SCH in the downlink.

[0029] The Dedicated Traffic Channel (DTCH) is a channel for one-to-one communication to an individual communication terminal for the transmission of user information. The DTCH exists in both the uplink and the downlink. The DTCH is mapped to the UL-SCH in the uplink and to the DL-SCH in the downlink.

[0030] The Multicast Traffic Channel (MTCH) is a downlink channel for the transmission of traffic data from the network to the communication terminal. The MTCH is a channel used only by communication terminals during MBMS reception. The MTCH is mapped to the Multicast Channel (MCH).

[0031] CGI refers to the Cell Global Identifier. ECGI refers to the E-UTRAN Cell Global Identifier. In LTE, the later LTE-A (Long Term Evolution Advanced), and UMTS (Universal Mobile Telecommunication System), Closed Subscriber Group (CSG) cells are introduced.

[0032] Location tracking of communication terminals is performed in units of areas consisting of one or more cells. Location tracking is performed to track the location of communication terminals even when they are in standby mode, and to enable them to be called, in other words, to allow them to receive calls. This area used for location tracking of communication terminals is called the tracking area.

[0033] Furthermore, 3GPP is working on the Long Term Evolution Advanced (LTE-A) standard as Release 10 (see Non-Patent Documents 3 and 4). LTE-A is based on the LTE wireless communication method and incorporates several new technologies.

[0034] In LTE-A systems, carrier aggregation (CA), which involves aggregating two or more component carriers (CCs) to support wider transmission bandwidths up to 100 MHz, is being considered. CA is described in Non-Patent Document 1.

[0035] When a CA is configured, the UE has a single RRC connection to the network (NW). In the RRC connection, one serving cell provides NAS mobility information and security inputs. This cell is called the Primary Cell (PCell). On the downlink, the carrier corresponding to the PCell is the Downlink Primary Component Carrier (DL PCC). On the uplink, the carrier corresponding to the PCell is the Uplink Primary Component Carrier (UL PCC).

[0036] Depending on the capabilities of the UE, secondary cells (SCells) are configured to form a set of serving cells together with PCells. On the downlink, the carrier corresponding to the SCell is the Downlink Secondary Component Carrier (DL SCC). On the uplink, the carrier corresponding to the SCell is the Uplink Secondary Component Carrier (UL SCC).

[0037] A set of serving cells consisting of one PCell and one or more SCells is configured for a single UE.

[0038] Furthermore, new technologies in LTE-A include technologies that support wider bandwidths (Wider bandwidth extension) and technologies such as Coordinated Multiple Point transmission and reception (CoMP). The CoMP technology being considered by 3GPP for LTE-A is described in Non-Patent Document 1.

[0039] Furthermore, 3GPP is considering using small eNBs (sometimes referred to as "small-scale base station equipment") that constitute small cells to cope with the enormous traffic of the future. For example, technologies are being considered to increase communication capacity by improving frequency utilization efficiency by installing a large number of small eNBs to constitute a large number of small cells. Specifically, this includes dual connectivity (DC), in which a UE connects to and communicates with two eNBs. DC is described in Non-Patent Document 1.

[0040] In some cases, among eNBs that perform dual connectivity (DC), one is called the "master eNB (abbreviated as MeNB)" and the other is called the "secondary eNB (abbreviated as SeNB)".

[0041] Mobile network traffic is on the rise, and communication speeds are also increasing. Further speed increases are expected once LTE and LTE-A are fully operational.

[0042] Furthermore, in response to the increasing sophistication of mobile communications, a fifth-generation (sometimes referred to as "5G") wireless access system is being considered, with the goal of launching services after 2020. For example, in Europe, the METIS organization has compiled the requirements for 5G (see Non-Patent Document 5).

[0043] In 5G wireless access systems, the requirements include achieving 1000 times the system capacity, 100 times the data transmission speed, one-tenth (1 / 10) the data processing delay, and 100 times the number of simultaneous connections for communication terminals compared to LTE systems, while also achieving further reductions in power consumption and equipment costs.

[0044] To meet these requirements, 3GPP is working on the 5G standard as Release 15 (see Non-Patent Documents 6-18). The technology for the wireless portion of 5G is called "New Radio Access Technology" ("New Radio" is abbreviated as "NR").

[0045] The NR system is being developed based on the LTE system and LTE-A system, but the following changes and additions have been made compared to the LTE system and LTE-A system.

[0046] For NR access, OFDM is used for the downstream direction, and OFDM and DFT-s-OFDM (DFT-spread-OFDM) are used for the upstream direction.

[0047] NR allows for the use of higher frequencies compared to LTE, in order to improve transmission speed and reduce processing delays.

[0048] In NR (Noise Reduction), cell coverage is ensured by forming a narrow beam-shaped transmission and reception range (beamforming) and changing the direction of the beam (beam sweeping).

[0049] In NR's frame configuration, various subcarrier intervals, i.e., various numerologies, are supported. In NR, regardless of the numerology, one subframe is 1 millisecond, and one slot consists of 14 symbols. Furthermore, the number of slots contained in one subframe is one for a numerology with a subcarrier interval of 15 kHz, and increases proportionally with the subcarrier interval for other numerologies (see Non-Patent Document 13 (TS38.211 V16.0.0)).

[0050] In NR, the downlink synchronization signal is transmitted from the base station as a synchronization signal burst (SS burst) at a predetermined period and for a predetermined duration. The SS burst consists of a synchronization signal block (SS block) for each beam of the base station. The base station transmits the SS block for each beam, changing beams within the duration of the SS burst. The SS block consists of P-SS, S-SS, and PBCH.

[0051] In noise reduction (NR), the effect of phase noise is reduced by adding a Phase Tracking Reference Signal (PTRS) as the downstream reference signal. Similarly, a PTRS is also added to the upstream reference signal.

[0052] In NR, Slot Format Indication (SFI) information has been added to the PDCCH to allow for flexible switching between DL / UL within a slot.

[0053] Furthermore, in NR, a portion of the carrier frequency band (sometimes referred to as the Bandwidth Part (BWP)) is pre-configured by the base station for the UE, and the UE performs transmission and reception with the base station in the BWP, thereby reducing the power consumption of the UE.

[0054] 3GPP is considering several data center configurations, including a data center with LTE and NR base stations connected to an EPC, a data center with NR base stations connected to a 5G core system, and a data center with LTE and NR base stations connected to a 5G core system (see Non-Patent Documents 12, 16, and 19).

[0055] Furthermore, 3GPP is considering several new technologies. For example, they are exploring the operation of terminals using multiple SIMs (Subscriber Identity Modules) (see Non-Patent Document 20). [Prior art documents] [Non-patent literature]

[0056] [Non-Patent Document 1] 3GPP TS 36.300 V16.0.0 [Non-Patent Document 2] 3GPP S1-083461 [Non-Patent Document 3] 3GPP TR 36.814 V9.2.0 [Non-Patent Document 4] 3GPP TR 36.912 V15.0.0 [Non-Patent Document 5] “Scenarios, requirements and KPIs for 5G mobile and wireless system”, ICT-317669-METIS / D1.1

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[0057] 3GPP is considering the operation of UEs using multiple SIMs. For example, measures are being considered for cases where the timing of paging to the UE from two networks overlaps, and for methods of notifying the type of data related to paging (see Non-Patent Document 20). However, a specific method for determining which network's paging to receive has not been disclosed. Therefore, for example, if the conflicting paging includes paging for emergency communications such as ETWS (Earthquake and Tsunami Warning System) or CMAS (Commercial Mobile Alert System), the UE may not be able to receive the paging for the emergency communications. As a result, the UE may not be able to receive the emergency communications quickly.

[0058] In view of the above issues, one of the objectives of this disclosure is to provide a technology that enables rapid network connectivity. [Means for solving the problem]

[0059] The terminal device relating to this disclosure is a terminal device having a plurality of SIMs (Subscriber Identity Modules) and configured to connect to a plurality of networks using the plurality of SIMs, wherein the plurality of networks include a first network including an AMF (Access and Mobility Management Function) and a second network, and the terminal device is configured to receive information from the AMF related to avoiding paging collisions between the plurality of networks. The communication system relating to this disclosure is a communication system including a terminal device having a plurality of SIMs (Subscriber Identity Modules) and configured to connect to a plurality of networks using the plurality of SIMs, wherein the plurality of networks include a first network including an AMF (Access and Mobility Management Function) and a second network, and the terminal device is configured to receive information from the AMF related to avoiding paging collisions between the plurality of networks. [Effects of the Invention]

[0060] According to this disclosure, rapid network connectivity will be possible.

[0061] The purpose, features, aspects, and advantages of this disclosure will become clearer from the following detailed description and accompanying drawings. [Brief explanation of the drawing]

[0062] [Figure 1] This is an explanatory diagram showing the configuration of wireless frames used in LTE communication systems. [Figure 2]This block diagram shows the overall configuration of the LTE communication system 200 as discussed in 3GPP. [Figure 3] This is a block diagram showing the overall configuration of the NR communication system 210 as discussed in 3GPP. [Figure 4] This is a diagram illustrating the configuration of a data center using eNBs and gNBs connected to the EPC. [Figure 5] This is a diagram showing the configuration of the DC using gNB connected to the NG core. [Figure 6] This is a diagram showing the configuration of the DC with eNBs and gNBs connected to the NG core. [Figure 7] This is a diagram showing the configuration of the DC with eNBs and gNBs connected to the NG core. [Figure 8] Figure 2 is a block diagram showing the configuration of the mobile terminal 202. [Figure 9] Figure 2 is a block diagram showing the configuration of base station 203. [Figure 10] This block diagram shows the configuration of MME. [Figure 11] This is a block diagram showing the configuration of 5GC. [Figure 12] This is a flowchart illustrating the general process from cell search to standby operation performed by a communication terminal (UE) in an LTE communication system. [Figure 13] This figure shows an example of a cell configuration in an NR system. [Figure 14] This is an architecture diagram showing an example of the connection between a multi-SIM equipped UE and multiple networks in Embodiment 1. [Figure 15] This figure shows a first example of the assignment of timing priorities for paging from multiple networks and the paging received by the UE, according to Embodiment 1. [Figure 16] This figure shows a second example of the assignment of timing priorities for paging from multiple networks and the paging received by the UE, according to Embodiment 1. [Figure 17]This sequence diagram shows an example of the stopping and restarting operation of RLF timers associated with switching the UE's transmission and reception destination in Embodiment 2. [Figure 18] This figure illustrates a modified example of Embodiment 3, specifically the assignment of a priority offset in a logical channel having a survival time requirement. [Figure 19] This figure illustrates a modified example of Embodiment 3, specifically the implicit control of the number of packet copies in a logical channel with a survival time requirement. [Modes for carrying out the invention]

[0063] Embodiment 1. Figure 2 is a block diagram showing the overall configuration of the LTE communication system 200 being discussed in 3GPP. Figure 2 will be explained below. The radio access network is called E-UTRAN (Evolved Universal Terrestrial Radio Access Network) 201. The mobile terminal equipment (hereinafter referred to as "User Equipment: UE") 202, which is a communication terminal device, can communicate wirelessly with the base station equipment (hereinafter referred to as "Base Station (E-UTRAN NodeB: eNB)") 203 and transmits and receives signals wirelessly.

[0064] Here, "communication terminal equipment" includes not only mobile terminal equipment such as portable mobile phone terminals, but also stationary devices such as sensors. In the following explanation, "communication terminal equipment" may sometimes be simply referred to as "communication terminal."

[0065] If the control protocol for the mobile terminal 202, such as RRC (Radio Resource Control), and the user plane (hereinafter sometimes referred to as U-Plane), such as PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer), are terminated at base station 203, then E-UTRAN is composed of one or more base stations 203.

[0066] The control protocol RRC (Radio Resource Control) between the mobile terminal 202 and the base station 203 performs functions such as broadcasting, paging, and RRC connection management. The states of the base station 203 and the mobile terminal 202 in RRC are RRC_IDLE and RRC_CONNECTED.

[0067] In RRC_IDLE mode, tasks such as PLMN (Public Land Mobile Network) selection, System Information (SI) notification, paging, cell re-selection, and mobility are performed. In RRC_CONNECTED mode, mobile terminals have an RRC connection and can send and receive data with the network. In RRC_CONNECTED mode, tasks such as handover (HO) and neighbor cell measurement are also performed.

[0068] Base station 203 consists of one or more eNB207 units. The system, comprising the core network EPC (Evolved Packet Core) and the wireless access network E-UTRAN201, is called EPS (Evolved Packet System). The EPC and E-UTRAN201 are sometimes collectively referred to as the "network."

[0069] The eNB207 is connected via an S1 interface to a Mobility Management Entity (MME), or a Serving Gateway (S-GW), or an MME / S-GW unit (hereinafter sometimes referred to as "MME unit") 204 that includes both an MME and an S-GW, and control information is communicated between the eNB207 and the MME unit 204. Multiple MME units 204 may be connected to a single eNB207. The eNB207s are connected to each other via an X2 interface, and control information is communicated between the eNB207s.

[0070] The MME unit 204 controls the connection between the higher-level device, specifically the higher-level node, which is the base station eNB 207, and the mobile terminal (UE) 202. The MME unit 204 constitutes the core network EPC. The base station 203 constitutes the E-UTRAN 201.

[0071] The base station 203 may constitute one cell or multiple cells. Each cell has a predetermined range called coverage, which is the range within which it can communicate with the mobile terminal 202, and wireless communication is performed with the mobile terminal 202 within that coverage. When one base station 203 constitutes multiple cells, each cell is configured to communicate with the mobile terminal 202.

[0072] Figure 3 is a block diagram showing the overall configuration of the 5G communication system 210 being discussed in 3GPP. Figure 3 will now be explained. The radio access network is called NG-RAN (Next Generation Radio Access Network) 211. UE 202 can communicate wirelessly with NR base station equipment (hereinafter referred to as "NR base station (NG-RAN NodeB: gNB)") 213 and transmits and receives signals wirelessly. The core network is called the 5G Core (5GC).

[0073] If the control protocol for UE202, such as RRC (Radio Resource Control), and the user plane (hereinafter sometimes referred to as U-Plane), such as SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer), are terminated at the NR base station 213, then the NG-RAN is composed of one or more NR base stations 213.

[0074] The functionality of the Radio Resource Control (RRC) control protocol between UE202 and NR base station 213 is the same as in LTE. The states of NR base station 213 and UE202 in RRC are RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE.

[0075] RRC_IDLE and RRC_CONNECTED are the same as in the LTE system. RRC_INACTIVE means that the connection between the 5G core and NR base station 213 is maintained while system information (SI) broadcasting, paging, cell re-selection, and mobility are performed.

[0076] The gNB217 is connected via an NG interface to an Access and Mobility Management Function (AMF), a Session Management Function (SMF), or a User Plane Function (UPF), or an AMF / SMF / UPF unit (hereinafter sometimes referred to as the "5GC unit") 214 that includes AMF, SMF, and UPF. Control information and / or user data are communicated between the gNB217 and the 5GC unit 214. The NG interface is a collective term for the N2 interface between the gNB217 and AMF, the N3 interface between the gNB217 and UPF, the N11 interface between AMF and SMF, and the N4 interface between UPF and SMF. Multiple 5GC units 214 may be connected to a single gNB217. The gNB217s are connected to each other via an Xn interface, and control information and / or user data are communicated between them.

[0077] Like base station 203, NR base station 213 may also consist of one or more cells. When one NR base station 213 consists of multiple cells, each cell is configured to communicate with UE 202.

[0078] The gNB217 may be divided into a Central Unit (CU) 218 ​​and a Distributed Unit (DU) 219. One CU218 is configured within the gNB217. One or more DU219s are configured within the gNB217. The CU218 is connected to the DU219 via an F1 interface, and control information and / or user data are communicated between the CU218 and the DU219.

[0079] In a 5G communication system, the Unified Data Management (UDM) function and Policy Control Function (PCF) described in Non-Patent Document 27 (3GPP TS23.501 V16.3.0) may be included. The UDM and / or PCF may be included in the 5GC section in Figure 3.

[0080] In a 5G communication system, the Non-3GPP Interworking Function (N3IWF) described in Non-Patent Document 27 (3GPP TS23.501 V16.3.0) may be included. In non-3GPP access with the UE, the N3IWF may terminate the Access Network (AN) with the UE.

[0081] Figure 4 shows the configuration of a DC with eNBs and gNBs connected to the EPC. In Figure 4, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 4, eNB223-1 acts as the master base station, and gNB224-2 acts as the secondary base station (this DC configuration is sometimes referred to as EN-DC). Figure 4 shows an example where the U-Plane connection between the MME unit 204 and gNB224-2 is made via eNB223-1, but it may also be made directly between the MME unit 204 and gNB224-2.

[0082] Figure 5 shows the configuration of a DC with gNBs connected to the NG core. In Figure 5, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 5, gNB224-1 acts as the master base station, and gNB224-2 acts as the secondary base station (this DC configuration is sometimes referred to as NR-DC). Figure 5 shows an example where the U-Plane connection between 5GC unit 214 and gNB224-2 is made via gNB224-1, but it may also be made directly between 5GC unit 214 and gNB224-2.

[0083] Figure 6 shows the configuration of a DC with eNBs and gNBs connected to the NG core. In Figure 6, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 6, eNB226-1 acts as the master base station, and gNB224-2 acts as the secondary base station (this DC configuration is sometimes referred to as NG-EN-DC). Figure 6 shows an example where the U-Plane connection between 5GC unit 214 and gNB224-2 is made via eNB226-1, but it may also be made directly between 5GC unit 214 and gNB224-2.

[0084] Figure 7 shows another configuration of a DC with eNBs and gNBs connected to the NG core. In Figure 7, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 7, gNB224-1 acts as the master base station, and eNB226-2 acts as the secondary base station (this DC configuration is sometimes referred to as NE-DC). Figure 7 shows an example where the U-Plane connection between 5GC unit 214 and eNB226-2 is made via gNB224-1, but it may also be made directly between 5GC unit 214 and eNB226-2.

[0085] Figure 8 is a block diagram showing the configuration of the mobile terminal 202 shown in Figure 2. The transmission process of the mobile terminal 202 shown in Figure 8 will now be explained. First, control data from the protocol processing unit 301 and user data from the application unit 302 are stored in the transmission data buffer unit 303. The data stored in the transmission data buffer unit 303 is passed to the encoder unit 304, where encoding processing such as error correction is performed. There may be data that is output directly from the transmission data buffer unit 303 to the modulation unit 305 without undergoing encoding processing. The data encoded by the encoder unit 304 is then modulated in the modulation unit 305. Precoding in MIMO may be performed in the modulation unit 305. The modulated data is converted into a baseband signal, then output to the frequency conversion unit 306, where it is converted to a wireless transmission frequency. After that, the transmission signal is sent from antennas 307-1 to 307-4 to the base station 203. Figure 8 illustrates the case where there are four antennas, but the number of antennas is not limited to four.

[0086] Furthermore, the reception processing of the mobile terminal 202 is performed as follows: A radio signal from the base station 203 is received by antennas 307-1 to 307-4. The received signal is converted from the radio reception frequency to a baseband signal by the frequency conversion unit 306, and demodulation processing is performed by the demodulation unit 308. Weight calculation and multiplication processing may also be performed in the demodulation unit 308. The demodulated data is passed to the decoder unit 309, where decoding processing such as error correction is performed. Of the decoded data, the control data is passed to the protocol processing unit 301, and the user data is passed to the application unit 302. The series of processes of the mobile terminal 202 are controlled by the control unit 310. Therefore, although the control unit 310 is omitted in Figure 8, it is connected to each of the units 301 to 309. In Figure 8, the number of antennas used by the mobile terminal 202 for transmission and the number of antennas used for reception may be the same or different.

[0087] Figure 9 is a block diagram showing the configuration of the base station 203 shown in Figure 2. The transmission process of the base station 203 shown in Figure 9 will now be explained. The EPC communication unit 401 transmits and receives data between the base station 203 and the EPC (MME unit 204, etc.). The 5GC communication unit 412 transmits and receives data between the base station 203 and the 5GC (5GC unit 214, etc.). The other base station communication unit 402 transmits and receives data with other base stations. The EPC communication unit 401, the 5GC communication unit 412, and the other base station communication unit 402 each exchange information with the protocol processing unit 403. Control data from the protocol processing unit 403, as well as user data and control data from the EPC communication unit 401, the 5GC communication unit 412, and the other base station communication unit 402, are stored in the transmission data buffer unit 404.

[0088] The data stored in the transmission data buffer unit 404 is passed to the encoder unit 405, where it undergoes encoding processing such as error correction. Some data may be output directly from the transmission data buffer unit 404 to the modulation unit 406 without undergoing encoding processing. The encoded data is then modulated in the modulation unit 406. Precoding in MIMO may be performed in the modulation unit 406. The modulated data is converted to a baseband signal, then output to the frequency conversion unit 407, where it is converted to a wireless transmission frequency. Subsequently, the transmission signal is sent from antennas 408-1 to 408-4 to one or more mobile terminals 202. Figure 9 illustrates the case with four antennas, but the number of antennas is not limited to four.

[0089] Furthermore, the reception processing of the base station 203 is performed as follows: A radio signal from one or more mobile terminals 202 is received by the antenna 408. The received signal is converted from the radio reception frequency to a baseband signal by the frequency conversion unit 407, and demodulation processing is performed by the demodulation unit 409. The demodulated data is passed to the decoder unit 410, where decoding processing such as error correction is performed. Of the decoded data, the control data is passed to the protocol processing unit 403, the 5GC communication unit 412, the EPC communication unit 401, or the other base station communication unit 402, while the user data is passed to the 5GC communication unit 412, the EPC communication unit 401, and the other base station communication unit 402. The series of processes of the base station 203 are controlled by the control unit 411. Therefore, although the control unit 411 is omitted in Figure 9, it is connected to each of the units 401 to 410. In Figure 9, the number of antennas used by the base station 203 for transmission and the number of antennas used for reception may be the same or different.

[0090] Figure 9 is a block diagram showing the configuration of base station 203, but base station 213 may have a similar configuration. Also, in Figures 8 and 9, the number of antennas on mobile terminal 202 and base station 203 may be the same or different.

[0091] Figure 10 is a block diagram showing the configuration of the MME. Figure 10 shows the configuration of the MME204a included in the MME unit 204 shown in Figure 2 above. The PDN GW communication unit 501 transmits and receives data between the MME204a and the PDN GW. The base station communication unit 502 transmits and receives data between the MME204a and the base station 203 via the S1 interface. If the data received from the PDN GW is user data, the user data is passed from the PDN GW communication unit 501 to the base station communication unit 502 via the user-plane communication unit 503 and transmitted to one or more base stations 203. If the data received from the base station 203 is user data, the user data is passed from the base station communication unit 502 to the PDN GW communication unit 501 via the user-plane communication unit 503 and transmitted to the PDN GW.

[0092] If the data received from the PDN GW is control data, the control data is passed from the PDN GW communication unit 501 to the control plane control unit 505. If the data received from the base station 203 is control data, the control data is passed from the base station communication unit 502 to the control plane control unit 505.

[0093] The control plane control unit 505 includes the NAS security unit 505-1, the SAE bearer control unit 505-2, and the idle state mobility management unit 505-3, and performs all processing for the control plane (hereinafter sometimes referred to as C-Plane). The NAS security unit 505-1 performs security for NAS (Non-Access Stratum) messages, etc. The SAE bearer control unit 505-2 performs management of SAE (System Architecture Evolution) bearers, etc. The idle state mobility management unit 505-3 performs mobility management in the standby state (also referred to as LTE-IDLE state or simply idle), generation and control of paging signals in the standby state, addition, deletion, updating, searching, and tracking area list management for one or more mobile terminals 202 under its umbrella.

[0094] The MME204a distributes paging signals to one or more base stations 203. The MME204a also performs mobility control in the idle state. The MME204a manages the tracking area list when the mobile terminal is in the idle state and when it is in the active state. The MME204a initiates the paging protocol by sending paging messages to cells belonging to the registered tracking area of ​​the UE. The management of the CSG, CSG ID, and whitelist of the eNB207 connected to the MME204a may be performed by the idle state mobility management unit 505-3.

[0095] Figure 11 is a block diagram showing the configuration of the 5GC. Figure 11 shows the configuration of the 5GC unit 214 shown in Figure 3. Figure 11 shows the case where the 5GC unit 214 shown in Figure 5 includes the configurations of AMF, SMF, and UPF. The Data Network communication unit 521 transmits and receives data between the 5GC unit 214 and the Data Network. The base station communication unit 522 transmits and receives data via the S1 interface between the 5GC unit 214 and the base station 203, and / or the NG interface between the 5GC unit 214 and the base station 213. If the data received from the Data Network is user data, the user data is passed from the Data Network communication unit 521 to the base station communication unit 522 via the user-plane communication unit 523, and transmitted to one or more base stations 203 and / or base station 213. If the data received from base station 203 and / or base station 213 is user data, the user data is passed from base station communication unit 522 to Data Network communication unit 521 via user plane communication unit 523 and transmitted to the Data Network.

[0096] If the data received from the Data Network is control data, the control data is passed from the Data Network communication unit 521 to the session management unit 527 via the user-plane communication unit 523. The session management unit 527 passes the control data to the control-plane control unit 525. If the data received from base station 203 and / or base station 213 is control data, the control data is passed from base station communication unit 522 to the control-plane control unit 525. The control-plane control unit 525 passes the control data to the session management unit 527.

[0097] The control plane control unit 525 includes the NAS security unit 525-1, the PDU session control unit 525-2, and the idle state mobility management unit 525-3, and performs all processing for the control plane (hereinafter sometimes referred to as C-Plane). The NAS security unit 525-1 performs security for NAS (Non-Access Stratum) messages, etc. The PDU session control unit 525-2 manages PDU sessions between the mobile terminal 202 and the 5GC unit 214, etc. The idle state mobility management unit 525-3 performs mobility management in the standby state (also referred to as RRC_IDLE state or simply idle), generation and control of paging signals in the standby state, addition, deletion, updating, searching, and tracking area list management for one or more mobile terminals 202 under its umbrella.

[0098] The 5GC unit 214 distributes paging signals to one or more base stations 203 and / or base station 213. The 5GC unit 214 also performs mobility control in the idle state. The 5GC unit 214 manages the tracking area list when the mobile terminal is in the idle state, inactive state, and active state. The 5GC unit 214 initiates the paging protocol by sending a paging message to a cell belonging to the tracking area where the UE is registered.

[0099] Next, an example of a cell search method in a communication system is shown. Figure 12 is a flowchart illustrating the process from cell search to standby operation performed by a communication terminal (UE) in an LTE communication system. When the communication terminal starts a cell search, in step ST601, it synchronizes the slot timing and frame timing using the first synchronization signal (P-SS) and the second synchronization signal (S-SS) transmitted from the surrounding base station.

[0100] P-SS and S-SS together are called the Synchronization Signal (SS). Each PCI assigned to a cell has a synchronization code that corresponds one-to-one with that PCI. 504 different PCI combinations are being considered. These 504 PCI combinations are used for synchronization, and the PCI of the synchronized cell is detected (identified).

[0101] Next, for the synchronized cell, step ST602 detects the cell-specific reference signal (CRS), which is a reference signal (RS) transmitted from the base station to each cell, and measures the received power (RSRP) of the RS. The reference signal (RS) uses a code that corresponds one-to-one with the PCI. By correlating with this code, it is possible to isolate it from other cells. By deriving the code for the RS of the cell from the PCI identified in step ST601, it becomes possible to detect the RS and measure the received power of the RS.

[0102] Next, in step ST603, from among the one or more cells detected up to step ST602, the cell with the best RS reception quality, for example, the cell with the highest RS reception power, i.e., the best cell, is selected.

[0103] Next, in step ST604, the PBCH of the best cell is received to obtain the broadcast information, which is the BCCH. The BCCH on the PBCH is mapped to the MIB (Master Information Block), which contains cell configuration information. Therefore, by receiving the PBCH and obtaining the BCCH, the MIB can be obtained. MIB information includes, for example, the DL (downlink) system bandwidth (also called transmission bandwidth configuration: dl-bandwidth), the number of transmitting antennas, and the SFN (System Frame Number).

[0104] Next, in step ST605, the DL-SCH of the cell is received based on the cell configuration information of the MIB, and SIB (System Information Block) 1 is obtained from the broadcast information BCCH. SIB1 contains information about accessing the cell, information about cell selection, and scheduling information for other SIBs (SIBk; an integer k ≥ 2). SIB1 also contains the Tracking Area Code (TAC).

[0105] Next, in step ST606, the communication terminal compares the TAC of the SIB1 received in step ST605 with the TAC portion of the Tracking Area Identity (TAI) in the Tracking Area List already held by the communication terminal. The Tracking Area List is also called the TAI list. TAI is identification information for identifying a tracking area and consists of MCC (Mobile Country Code), MNC (Mobile Network Code), and TAC (Tracking Area Code). MCC is the country code. MNC is the network code. TAC is the code number of the tracking area.

[0106] If, as a result of the comparison in step ST606, the TAC received in step ST605 is the same as a TAC included in the tracking area list, the communication terminal enters a waiting state in that cell. If, after comparison, the TAC received in step ST605 is not included in the tracking area list, the communication terminal requests a change in the tracking area through that cell to the Core Network (EPC), which includes the MME, etc., in order to perform a Tracking Area Update (TAU).

[0107] In the example shown in Figure 12, an example of the operation from cell search to standby in the LTE system is shown. However, in the NR system, in step ST603, the best beam may be selected in addition to the best cell. Also in the NR system, in step ST604, beam information, such as a beam identifier, may be obtained. Also in the NR system, in step ST604, scheduling information for the Remaining Minimum SI (RMSI) may be obtained. In the NR system, in step ST605, the RMSI may be received.

[0108] The devices constituting the core network (sometimes referred to as "core network devices") update the tracking area list based on the identification number (UE-ID, etc.) of the communication terminal sent from the communication terminal along with the TAU request signal. The core network devices send the updated tracking area list to the communication terminal. The communication terminal rewrites (updates) its TAC list based on the received tracking area list. After that, the communication terminal enters a waiting state in that cell.

[0109] The proliferation of smartphones and tablet devices has led to an explosive increase in cellular wireless communication traffic, raising concerns about a shortage of wireless resources worldwide. To address this, efforts are being made to improve frequency utilization efficiency by reducing the number of cells and promoting spatial separation.

[0110] In conventional cell configurations, cells composed of eNBs have relatively wide coverage. Traditionally, cells are configured to cover a certain area through the relatively wide coverage of multiple cells composed of multiple eNBs.

[0111] When subdivided into smaller cells, the cells composed of eNBs have narrower coverage than cells composed of conventional eNBs. Therefore, as before, a larger number of subdivided eNBs are needed to cover a given area compared to conventional eNBs.

[0112] In the following explanation, cells with relatively high coverage, such as those composed of conventional eNBs, will be referred to as "macrocells," and the eNBs that make up macrocells will be referred to as "macro eNBs." Similarly, cells with relatively low coverage, such as those that have been resized into smaller cells, will be referred to as "small cells," and the eNBs that make up small cells will be referred to as "small eNBs."

[0113] Macro eNB may be, for example, a "Wide Area Base Station" as described in Non-Patent Document 7.

[0114] A small eNB may be, for example, a low-power node, a local area node, or a hotspot. Alternatively, a small eNB may be a pico eNB constituting a picocell, a femto eNB constituting a femtocell, a HeNB, an RRH (Remote Radio Head), an RRU (Remote Radio Unit), an RRE (Remote Radio Equipment), or an RN (Relay Node). Furthermore, a small eNB may be a "Local Area Base Station" or "Home Base Station" as described in Non-Patent Document 7.

[0115] Figure 13 shows an example of a cell configuration in NR. In an NR cell, a narrow beam is formed and transmitted by changing its direction. In the example shown in Figure 13, base station 750 uses beam 751-1 to transmit and receive with a mobile terminal at a certain time. At other times, base station 750 uses beam 751-2 to transmit and receive with a mobile terminal. Similarly, base station 750 uses one or more of beams 751-3 to 751-8 to transmit and receive with a mobile terminal. In this way, base station 750 configures a wide-area cell.

[0116] Figure 13 shows an example where the base station 750 uses eight beams, but the number of beams may be different from eight. Also, in the example shown in Figure 13, the base station 750 uses one beam simultaneously, but it may use multiple beams.

[0117] A UE may be connected to or capable of connecting to multiple networks. Hereinafter, "connected" may include not only an actually connected state but also a state of being capable of connecting. A UE may connect to these multiple networks using multiple SIMs. A UE may have only one set of transceivers or multiple sets of transceivers. These multiple networks may be PLMNs, non-public networks (NPNs), or private networks. Connections to these multiple networks may be made in parallel.

[0118] Regarding the connection between the UE and each NW, the UE's RRC state may be RRC_CONNECTED, RRC_INACTIVE, or RRC_IDLE. The UE's CM state may be CM-IDLE or CM-CONNECTED. The UE may be in the RRC_CONNECTED state or the CM-CONNECTED state for two or more of the multiple NWs it connects to. As another example, the UE may be in the RRC_CONNECTED state or the CM-CONNECTED state for only one of the multiple NWs it connects to.

[0119] Figure 14 is an architecture diagram showing an example of a connection between a UE that uses multiple SIMs (hereinafter sometimes referred to as a Multi-SIM UE) and multiple networks. In Figure 14, the Multi-SIM UE is connected in parallel to NW#1 and NW#2.

[0120] In the example shown in Figure 14, UE1400 connects to gNB1401 on NW#1. UE1400 also connects to gNB1411 on NW#2. gNB1401 connects to AMF1402 and UPF1403 on NW#1. SMF1404 on NW#1 connects to AMF1402 and UPF1403. gNB1411 connects to AMF1412 and UPF1413 on NW#2. SMF1414 on NW#2 connects to AMF1412 and UPF1413.

[0121] Figure 14 shows an example where the UE1400 is connected to two networks, but the UE1400 may be connected to three or more networks. Furthermore, one or more of the two networks to which the UE1400 is connected may be NPN (Non-Pronunciation Network). The same applies when the UE1400 is connected to three or more networks.

[0122] In a UE connected in parallel to multiple networks, overlapping paging timings may occur (hereinafter sometimes referred to as paging collisions). A UE experiencing a paging collision may have only one set of transceivers. In this case, the UE can only receive paging from one of the networks. Therefore, for example, if the conflicting paging includes paging for emergency communications such as ETWS or CMAS, the UE may not be able to receive the paging for those emergency communications. As a result, the UE may not be able to receive the emergency communications quickly.

[0123] This first embodiment discloses a method for solving the aforementioned problems.

[0124] Priorities are assigned to the timing at which paging may be sent. These priorities may hereafter be referred to as timing priorities. Priorities are also assigned to the type of paging. These priorities may hereafter be referred to as type priorities.

[0125] The timing priority may be, for example, two levels or three or more levels. Parameters related to the timing priority may also be provided.

[0126] The type priority may be, for example, two levels or three or more levels. Parameters related to type priority may also be provided.

[0127] A mapping is made between timing priority and type priority. For example, if both timing priority and type priority consist of two levels, a higher timing priority may be mapped to a higher type priority, and a lower timing priority may be mapped to a lower type priority. At a paging timing of a predetermined timing priority, a paging of a predetermined type priority may be made available for transmission. For example, at a certain paging transmission timing, a paging with a type priority equal to or lower than that of the timing priority may be transmitted. When the timing of paging from base stations of multiple networks conflict, the UE may receive the paging with the higher timing priority among the conflicting pagings. When receiving a paging with a high timing priority, the UE may switch the transmitting and receiving network. The connection between the UE and the base stations of the transmitting and receiving network may be RRC_CONNECTED, RRC_INACTIVE, or RRC_IDLE. This allows the UE to receive paging related to emergency communications with priority over other paging.

[0128] As another example, a high type priority may be sent with a low timing priority. The aforementioned operation may be applied, for example, when a paging with a predetermined timing priority cannot be received due to a timing conflict with a paging with an even higher timing priority from another network. This allows for the rapid reception of the paging with the predetermined timing priority in the aforementioned case.

[0129] The UE may expect that paging with a type priority equal to or lower than the timing priority at the time of paging will be sent. In other words, the UE may expect that no paging with a type priority greater than the timing priority at the time of paging will be sent. In the foregoing, a type priority equal to or lower than the timing priority may be a type priority less than the timing priority, and a paging with a type priority greater than the timing priority may be a paging with a type priority equal to or higher than the timing priority.

[0130] As an example of timing priority assignment, when timing priority is divided into two levels, the higher and lower timing priorities may be assigned alternately for each PF (Paging Frame). The higher and lower timing priorities may be assigned alternately for each PO (Paging Occasion). The higher and lower timing priorities may be assigned alternately for each PDCCH monitoring occasion used for paging reception.

[0131] The paging for which type priority is assigned may be downlink data paging or voice call paging. The voice call paging may be normal incoming call paging or callback voice call paging from an emergency call. Other examples of paging for which type priority is assigned may be SI update paging or emergency communication paging. The emergency communication may be, for example, a PWS (Public Warning System). The emergency communication may be, for example, an ETWS (Earthquake and Tsunami Warning System), a CMAS (Commercial Mobile Alert System), an EU-ALERT (European Public Warning System), a KPAS (Korean Public Alert System), or other emergency communication.

[0132] Emergency communications for private networks (or non-public networks) may be provided. Emergency communications for private networks may be included in the aforementioned emergency communications. This would enable, for example, rapid notification to the UE of problems within a premises where a private network is applied.

[0133] As an example of assigning priority levels by type, if there are two levels of priority, emergency communications and SI updates may be assigned a higher priority, while other types of paging may be assigned a lower priority. As another example, if there are three levels of priority by type, emergency communications may be assigned a higher priority, SI updates and voice calls may be assigned a medium priority, and other types of paging may be assigned a lower priority.

[0134] The number of levels for timing priority and type priority may be the same. This allows for, for example, avoiding complexity in the mapping between timing priority and type priority. Alternatively, the number of levels for timing priority and type priority may be different. This allows for, for example, increased flexibility in the mapping between timing priority and type priority.

[0135] Timing priorities may be assigned to each Paging Frame (PF). This allows network equipment to perform timing priority assignment with less processing effort. Another example is that timing priorities may be assigned to each Paging Occasion (PO). This allows for increased flexibility in timing priority assignment. Yet another example is that timing priorities may be assigned to each PDCCH monitoring occasion used for paging reception. This allows for even greater flexibility in timing priority assignment.

[0136] As another example, timing priorities may be assigned for each DRX cycle. This can, for example, reduce the amount of processing required for timing priority assignment.

[0137] The assignment of timing priorities may be determined by the standard. This can, for example, avoid design complexity in communication systems.

[0138] As another example, the core network may determine the timing priority assignment. This allows for increased flexibility regarding the timing priority assignment, for example. The core network may be, for example, an AMF or a PCF. The core network may notify base stations of the determined assignment. Base stations may individually notify or broadcast the assignment information to UEs. As another example of notifying the assignment information, the core network may notify the UE directly. For example, an AMF may notify the UE of the information using NAS signaling.

[0139] Another example of timing priority allocation is that the base station may determine the allocation. This would, for example, allow for greater flexibility in timing priority allocation. The base station may individually notify or broadcast information regarding the allocation to the UE.

[0140] Parameters may be provided for determining timing priority. These parameters may, for example, use UE identifiers, or they may be parameters similar to the PCCH configuration information (PCCH-Config) disclosed in Non-Patent Document 22 (TS38.331). A method for determining timing priority from these parameters may be defined in the standard. This may, for example, reduce the size of notifications for the information necessary to determine timing priority.

[0141] Each network may determine the value of the parameter and notify the UE. This notification may be made via a base station. Alternatively, the base station may determine the value of the parameter and notify or broadcast it to the UE. Alternatively, the value of the parameter may be determined on a per-cell basis.

[0142] An average value for timing priority may be established. This average value may be the same across networks, for example, or the same across base stations. This prevents, for example, the UE's paging receiving partners from being biased towards a particular network.

[0143] As another example, the average value may differ between networks. This allows for adjustments between networks regarding, for example, the ease of receiving paging for the UE. As yet another example, the average value may differ between base stations. This allows for adjustments between base stations regarding the ease of receiving paging for the UE.

[0144] The average value of the timing priority can also be determined by the standard, the core network, or the base station, similar to the timing priority assignment.

[0145] Examples of information regarding timing priority assignments that the core network and / or base stations notify or broadcast to the UE are disclosed below, including (1) to (8).

[0146] (1) Information regarding the number of stages in timing priority.

[0147] (2) The value of the timing priority.

[0148] (3) Information regarding paging timing.

[0149] (4) Information regarding the timing priority assignment pattern.

[0150] (5) Information regarding the timing priority assignment cycle.

[0151] (6) Standard paging timing.

[0152] (7) Information that determines the paging timing for each timing priority.

[0153] (8) A combination of the above (1) to (7).

[0154] The number of stages in (1) above may be, for example, 2, or 3 or more. For example, if no timing priority is assigned, the number of stages in (1) above may be 1. The UE may use the information in (1) above to obtain the number of timing priority stages. This makes it possible to reduce the amount of processing required for the UE to understand the timing priority assignment.

[0155] The information in (2) above may, for example, be information indicating high or low priority when the number of stages in (1) above is 2. The UE may use the information in (2) above to obtain the timing priority. This makes it possible to reduce the amount of processing required for the UE to understand the timing priority assignment.

[0156] The information in (3) above may, for example, indicate which PF it is among the PFs within the DRX period. Alternatively, the information in (3) above may, for example, indicate which PO it is among the POs within the PF. Alternatively, the information in (3) above may, for example, indicate which paging PDCCH monitoring occasion it is among the paging PDCCH monitoring occasions within the PO. Another example is that the information may indicate which PO or paging PDCCH monitoring occasion it is among the PO or paging PDCCH monitoring occasions within the DRX period. The information in (3) above allows the UE to quickly determine the paging timing to which a predetermined timing priority is assigned.

[0157] The information in (3) above may also include, as another example, parameters used to determine paging timing. These parameters may include some or all of the broadcast information from the base station of the network, for example, the PCCH configuration information (PCCH-Config) disclosed in Non-Patent Document 22 (TS38.331). This makes it possible to reduce the processing load on the base station in notifications from the base station to the UE, for example.

[0158] The information in (4) above may, for example, indicate a pattern in the case of a two-stage timing priority system where high timing priority and low timing priority are alternately assigned to each PF. Alternatively, the information in (4) above may indicate a pattern where high timing priority is assigned twice in a row, followed by low timing priority being assigned twice in a row, and so on. The PF mentioned above may be a PO or a PDCCH monitoring occasion for paging. The information in (4) above allows the UE to quickly grasp the timing priority assignment.

[0159] The information in (5) above may, for example, be information relating to the period of the pattern in (4) above. The information in (5) above may be given at a period different from the DRX period. For example, the period of the timing priority assignment pattern may span multiple DRX periods. This makes it possible to avoid situations such as when paging at a predetermined paging timing in one network has a lower timing priority than paging timing in another network and is always unable to be received.

[0160] The information in (6) above may, for example, be information about the paging timing to which a high timing priority is assigned when high and low timing priorities are alternately assigned to each PF. The information in (6) above may also include information about the timing priority at the reference paging timing. This makes it possible to prevent discrepancies in understanding regarding the assignment of timing priorities between the base station and the UE. As a result, it becomes possible to improve the stability of operation in the communication system.

[0161] The information in (7) above may, for example, indicate which PF, PO, or PDCCH monitoring occasion for paging is assigned within the DRX period for each timing priority. The aforementioned DRX period may be a PF or a PO. The information in (7) above allows the UE to quickly determine the paging timing to which a given timing priority is assigned.

[0162] The information in (7) above may, as another example, include parameters used to determine the paging timing for each timing priority. These parameters may include some or all of the broadcast information from the base stations of the network, for example, the PCCH configuration information (PCCH-Config) disclosed in Non-Patent Document 22 (TS38.331). This makes it possible to improve the flexibility of paging timing settings in a communication system, for example.

[0163] The correspondence between timing priority and type priority may be determined by a standard. In determining this correspondence, for example, the message identifier disclosed in section 9.4.1.2.2 of Non-Patent Document 21 (TS23.041 V16.2.0) may be used. This makes it possible to avoid design complexity in communication systems, for example.

[0164] As another example, the core network may determine the correspondence between timing priority and type priority. This allows for increased flexibility in the mapping between the two priorities, for example. The core network may be, for example, an AMF or a PCF. The core network may notify base stations of the information regarding the determined correspondence. Base stations may individually notify or broadcast the information regarding the correspondence to UEs. As yet another example, the core network may notify the UE directly of the information. For example, an AMF may notify the UE of the information using NAS signaling.

[0165] As another example, the base station may determine the correspondence between timing priority and type priority. This would, for example, allow for greater flexibility in the mapping between the two priorities. The base station may individually notify or broadcast information regarding this mapping to the UE.

[0166] Another example of the mapping between timing priority and type priority is the combination described above. For example, the standard may define a predetermined range for the type priority to be associated with each timing priority, and the core network may determine the mapping using the predetermined range defined in the standard. This would allow for flexible implementation of the mapping in, for example, a communication system.

[0167] The assignment of type priority may be determined by a standard. For example, the Message Identifier disclosed in section 9.4.1.2.2 of Non-Patent Document 21 (TS23.041 V16.2.0) may be used for this assignment. This makes it possible to avoid design complexity in communication systems, for example.

[0168] As another example, the core network may determine the assignment of type priority. This allows for increased flexibility regarding the assignment of type priority, for example. The core network may be, for example, an AMF or a PCF. The core network may notify base stations of the information regarding the determined assignment. Base stations may individually notify or broadcast the information regarding the assignment to UEs. As another example of notifying information regarding the assignment, the core network may notify the UE directly. For example, an AMF may notify the UE of the information using NAS signaling.

[0169] Another example of type priority assignment is that the base station may determine the assignment. This would, for example, allow for greater flexibility in type priority assignment. The base station may individually notify or broadcast information regarding the assignment to the UE.

[0170] As another example of assigning type priority, the aforementioned combination may be used. For example, the standard may define a predetermined range for the type priority assigned to each type of paging, and the core network may determine the type priority using the predetermined range defined in the standard. This would allow for flexible assignment of paging type priority in a communication system, for example.

[0171] The UE receives the paging with the higher timing priority from among multiple pagings from networks with conflicting timings. The UE may perform this operation even if it has a single receiver. The UE may switch the receiving network when receiving the paging with the higher timing priority. This allows the UE to receive the paging with the higher priority from among multiple pagings with conflicting timings.

[0172] The UE may choose to completely ignore all paging from multiple network paging systems where some timing conflicts occur, except for the one with the highest timing priority. This can, for example, reduce the UE's power consumption.

[0173] The UE may notify the base station of paging that does not perform a receive operation (hereinafter sometimes referred to as non-received paging). This information may also include information about paging from other networks (hereinafter sometimes referred to as conflicting networks) that conflict with the non-received paging (hereinafter sometimes referred to as conflicting network paging).

[0174] Examples of information regarding non-received paging include (1) to (15) below.

[0175] (1) Information regarding the timing of non-received paging.

[0176] (2) Information regarding the timing priority of non-received paging.

[0177] (3) Information regarding the identifier of the collision network.

[0178] (4) Information regarding the timing of collision network paging.

[0179] (5) Information regarding numerology in collision networks.

[0180] (6) Information regarding frame timing in collision networks.

[0181] (7) Information used to derive the timing of collision network paging.

[0182] (8) Information regarding the beam used for communication with the colliding network.

[0183] (9) Information regarding the synchronization signal of the collision network.

[0184] (10) Information regarding Radio Access Technology (RAT) in collision networks.

[0185] (11) Information regarding the timing priority of paging in a collision network.

[0186] (12) Information regarding the operation of multiple SIMs within the UE.

[0187] (13) Information indicating a request for a change in settings regarding non-received paging.

[0188] (14) Information regarding type priority.

[0189] (15) A combination of the above (1) to (14).

[0190] The information in (1) above may also indicate which PF, PO, or PDCCH monitoring occasion for paging within the DRX period is a non-received paging. The information in (1) above may also include information using the frame number, subframe number, slot number, and symbol number of the non-received paging. This allows for rapid notification from the UE to the base station, for example.

[0191] The information in (2) above may be the same as the information in (2) disclosed as information regarding timing priority assignment that the core network and / or base station notifies or broadcasts to the UE. The information in (2) above makes it possible, for example, to reduce the processing load when the base station reassigns timing priority.

[0192] The information in (3) above may, for example, be the PLMN-ID of the other network, or it may include the NPN-ID disclosed in Non-Patent Document 25 (TR23.734), or it may include the CAG-ID. This allows, for example, the base station to identify the network that should avoid paging collisions, and as a result, the complexity of the avoidance process can be avoided.

[0193] Another example of the information described in (3) above is an identifier that uniquely identifies the UE. This identifier may be, for example, a 5G-GUTI (5G Globally Unique Temporary Identifier). The base station may extract the PLMN-ID of the other network from the 5G-GUTI. This allows the base station to obtain, for example, the identifier of the other network and the identifier of the UE simultaneously. As a result, the base station can obtain information used to derive paging timing in the other network with less signaling.

[0194] The information in (4) above may be, for example, a Paging Frame (PF), a Paging Occasion (PO), a PDCCH monitoring occasion used for paging reception, or a combination of several of the above. This makes it possible to reduce the processing load on the base station in avoiding paging collisions, for example.

[0195] The information in (4) above may also include, as another example, information regarding the time of paging timing in other networks. This time information may include, for example, the time at the start of the paging timing, the time at the end of the paging timing, information regarding the duration of the paging timing, or a combination of the above. The paging timing may be a PF (Paging Frame), a PO (Paging Occasion), a PDCCH monitoring occasion used for paging reception, or a combination of the above in other networks. This makes it possible to reduce the processing load on the base station in avoiding paging collisions, for example.

[0196] The information in (5) above may be, for example, the subcarrier spacing, slot length, or symbol length used by the UE when receiving paging from another NW. The information in (5) above may also be the parameter μ disclosed in Section 4.2 of Non-Patent Document 13 (TS38.211). This makes it possible to improve, for example, the reliability of paging collision avoidance by the base station.

[0197] The information in (6) above may be, for example, the difference in frame timing between the notification base station and a base station of another network, given in SFN units, subframe units, slot units, symbol units, or the smallest unit on the communication system (e.g., Ts units), or a combination thereof. The slots mentioned above may be slots at the notification base station or slots in the other network. This makes it possible to reduce the processing load on the base station in avoiding paging collisions, for example.

[0198] The information in (6) above may, as another example, be a predetermined point in time in another network, for example, the time at the boundary of a predetermined SFN. The boundary may be the beginning or the end of the SFN. The information in (6) above may, as another example, be the time at a predetermined subframe boundary, a predetermined slot boundary, or a predetermined symbol boundary. The UE may obtain this information by cell search on the other network, or from broadcast information from the other network. This makes it possible to reduce, for example, the amount of processing required for the UE to make such a notification.

[0199] The information in (7) above may include, for example, the identifier of the UE in another network, or parameters used to determine the paging timing in that other network. These parameters may include some or all of the broadcast information from the base station of the network, for example, the PCCH configuration information (PCCH-Config) disclosed in Non-Patent Document 22 (TS38.331). This makes it possible to reduce the amount of processing required for the notification from the UE, for example.

[0200] The aforementioned identifier relating to the information in (7) above may be, for example, a UE_ID disclosed in section 7.1 of Non-Patent Literature 26 (TS38.304), or a 5G-S-TMSI (5G S-Temporary Mobile Subscription Identifier), 5G-TMSI (5G Temporary Mobile Subscription Identifier), or 5G-GUTI disclosed in Non-Patent Literature 27 (TS23.501).

[0201] The aforementioned parameters relating to the information in (7) above may include the Discontinuous Reception (DRX) period (T) of the UE, the total number of paging frames (N) in the period, the number of paging occasions (Ns) in the PF, the offset (PF_offset) used in the PF determination, or the first PDCCH monitoring occasion (first-PDCCH-MonitoringOccasionOfPO) in the PO.

[0202] The information in (8) above may be information about the beam that the UE is using to receive from the notifying base station. The beam may be information about the beam that the UE is using to receive SS blocks from the base station. The beam may be information about the beam that the UE is using to receive broadcast information from the base station, such as SIB1 or RMSI (Remaining Minimum System Information). The base station may use the information in (8) above to change the paging timing in the beam in which the UE is located. The base station may change the broadcast information in the beam. This allows the base station to flexibly change the paging timing, for example.

[0203] The information in (9) above may be, for example, information about the SS burst period, or the duration of SS block transmission in one SS burst period. The base station may use the information in (9) above to set the paging timing to avoid multiple SS burst periods transmitted from base stations of other networks, or to set the paging timing to avoid the duration of SS block transmission. The UE may use this information to receive a synchronization signal from a base station of another network. The UE may receive the paging after receiving the synchronization signal. This makes it possible to prevent, for example, timing discrepancies in the UE's paging reception.

[0204] The information in (10) above may, for example, be information indicating that the base station of another network is an NR base station or information indicating that it is an LTE base station. The base station may use this information to change the paging timing. For example, if the base station of another network is an LTE base station and the paging timing at the LTE base station is fixed, the base station may change the period of the paging timing. This can reduce, for example, the possibility of failure to avoid paging collisions in the communication system.

[0205] The information in (11) above may be, for example, the timing priority value of a paging that is in conflict with an unreceived paging, or it may be information regarding the timing priority assigned to paging from a base station of another network. A base station may use the information in (11) above to change the timing priority of an unreceived paging, or to change the timing priority assignment to its own paging. This can reduce, for example, the likelihood of failure to avoid paging collisions in a communication system.

[0206] The information in (12) above may, for example, be information indicating whether the UE is a multi-SIM equipped UE, or it may be information regarding operation using multiple SIMs. Information regarding operation using multiple SIMs may, for example, include the number of transmitters and / or receivers in the UE, the number of networks that the UE can connect to, or the number of RRCs that the UE can hold. Information regarding operation using multiple SIMs may also be information regarding combinations of RRC states in the UE, for example, information indicating whether it can be RRC_CONNECTED simultaneously with multiple base stations among the base stations of multiple networks. The UE may, for example, include this information in its UE capabilities and notify the base station of it. The base station may use this information for sending and receiving data with the UE. This can, for example, improve the efficiency of the communication system.

[0207] The information in (13) above may be, for example, information requesting a change in the paging timing at the base station, information requesting a change in the assignment of paging timing priorities at the base station, information requesting a change in the correspondence between paging timing priorities and type priorities, or a combination of several of the above. The base station may use this information to change the paging timing, change the assignment of paging timing priorities, or change the assignment of paging timing priorities and type priorities. This makes it possible, for example, to reduce the amount of processing required at the base station for changing the above-mentioned settings.

[0208] The information in (14) above may, for example, be information showing the correspondence between paging timing priority and type priority in a collision network, or it may be similar information in the own network. The base station may use the information in (14) above to change the paging timing, change the assignment of paging timing priority, or change the assignment of paging timing priority and type priority. This makes it possible, for example, for the base station to reduce the amount of processing required to change the above-mentioned settings.

[0209] The UE may use RRC signaling to notify the base station of information regarding unreceived paging. For example, the UE may use an RRC Setup Request in the notification. The UE may use the RRC Setup Request signaling in the notification when the RRC state regarding the connection with the base station is RRC_IDLE. This allows the UE to quickly notify the base station. As another example, the UE may use an RRC Setup Complete in the notification. The UE may use the RRC Setup Complete signaling in the notification when the RRC state regarding the connection with the base station transitions from RRC_IDLE to RRC_CONNECTED. This allows the UE to notify the base station with more information.

[0210] As another example, the UE may use an RRC Resumption Request in the notification. The UE may use the RRC Resumption Request signaling in the notification when the RRC state for the connection with the base station is RRC_INACTIVE. This allows the UE to send the notification to the base station more quickly, for example. As yet another example, the UE may use an RRC Resumption Complete in the notification. The UE may use the RRC Resumption Complete signaling in the notification when the RRC state for the connection with the base station transitions from RRC_INACTIVE to RRC_CONNECTED. This allows the UE to notify the base station with more information, for example.

[0211] As another example, the UE may use "RRCReconfigurationComplete" in the notification. This allows the UE to notify the base station with more information.

[0212] As another example, new RRC signaling may be provided. For instance, a signaling called RRCReconfigurationRequest may be provided and used, or a signaling called PagingConfigurationInformationNotification may be provided and used.

[0213] Another example of notification from the UE to the base station is the use of MAC signaling. This allows the UE to quickly notify of paging collisions, for example. Another example is the use of L1 / L2 signaling. This allows the UE to even more quickly notify of paging collisions, for example.

[0214] The base station may use the non-received paging information obtained from the UE to change the timing priority assignment, change the paging timing, change the correspondence between timing priority and type priority, or change the type priority assignment to each paging type.

[0215] The base station may change the paging timing using the notification from the UE. The base station may change the parameters used to determine the paging timing. These parameters may be, for example, the PCCH configuration information (PCCH-Config) disclosed in Non-Patent Document 22 (TS38.331).

[0216] The base station may uniformly assign timing priorities, establish the correspondence between timing priorities and type priorities, assign type priorities to each paging type, and / or change the timing of paging to the UEs under the cell. The base station may also notify the UEs under the cell of information regarding such changes. The UEs under the cell may use the information regarding such changes to update settings related to paging timing priorities, settings related to paging timing, settings related to the correspondence between timing priorities and type priorities, and settings related to the assignment of type priorities to each paging type.

[0217] For example, the base station may notify its subordinate UEs of the changed parameter. For example, the base station may include the changed parameter in the SIB1 and notify it. The UE may use this notification to change the timing at which it receives paging (hereinafter sometimes referred to as the paging reception timing).

[0218] As another example, the base station may change the parameter for each beam. The broadcast information from the base station may also differ for each beam. This can, for example, improve the flexibility of parameter settings in a communication system.

[0219] As another example, a base station may individually configure timing priorities, the correspondence between timing priorities and type priorities, the assignment of type priorities to each paging type, and / or changes to the timing of paging on a UE-by-UE basis. The base station may individually notify the UEs under its cell of information regarding such changes. For example, RRC individual signaling may be used for such notification. The UEs may use information regarding such changes to update settings for paging timing priorities, settings for paging timing, settings for the correspondence between timing priorities and type priorities, and settings for the assignment of type priorities to each paging type.

[0220] For example, a base station may individually change the parameters used to determine the paging timing for each UE. The base station may individually notify the UE of the changed parameters. The base station may also individually notify the UE of the changed parameters by including them in RRC signaling, for example, RRC Reconfiguration. The UE may use this individual notification to change the paging reception timing. This makes it possible to avoid the complexity of processing related to changes in paging timing in, for example, a communication system.

[0221] As another example, the base station may set or change the parameter for multiple UEs collectively. For example, the base station may set and / or change the parameter for multiple multi-SIM UEs collectively. For example, the aforementioned multiple multi-SIM UEs may be all multi-SIM UEs under the base station's umbrella. For example, the aforementioned multiple multi-SIM UEs may have the same or different network destinations other than the base station. The multiple multi-SIM UEs may be treated as a UE group. The base station sets and / or changes the parameter for the UE group.

[0222] The base station may collectively notify the multiple UEs of the parameters it has set and / or modified for them. For example, RRC signaling may be used for this notification. A specific UE-ID, such as a multicast UE-ID, may be included in the collective notification. The multiple UEs may use the collective notification to set and / or modify the parameters. This can, for example, reduce the amount of signaling between the base station and the multiple UEs.

[0223] The aforementioned collective notification from the base station to multiple UEs may also be performed in other RRC signaling. This would, for example, further reduce the amount of signaling between the base station and multiple UEs.

[0224] The UE may notify base stations in other networks of the modified parameter notified by the base station. The UE may include information about the UE's identifier in the notification to the base stations in other networks. This identifier may be an identifier assigned in the network of the base station that modified the parameter. The base stations in other networks may or may not use the parameter to change the paging timing in their networks. This allows, for example, the paging timing in the other networks to be changed while avoiding the notified parameter. As a result, paging collisions after the paging timing change can be prevented.

[0225] A base station may request the AMF to change the identifier of a UE. The base station may make such a request only when it is not possible to avoid a paging collision by changing only the parameters used to determine the paging timing (e.g., PCCH configuration information (PCCH-Config)). The base station may not make such a request to the AMF when a paging collision is possible by changing the parameters. This prevents unnecessary changes to the identifier when, for example, a paging collision can be avoided by changing only the PCCH configuration information. The request may include one or more UE identifiers to be changed. Signaling on the N2 interface may be used for the request. New signaling, such as an N2 UE configuration update request signaling, may be provided and used. The identifier of the UE may be, for example, a UE_ID disclosed in section 7.1 of Non-Patent Document 26 (TS38.304), or a 5G-S-TMSI (5G S-Temporary Mobile Subscription Identifier), 5G-TMSI (5G Temporary Mobile Subscription Identifier), or 5G-GUTI disclosed in Non-Patent Document 27 (TS23.501). The AMF may use the signaling to modify the identifier of the UE.

[0226] The base station may notify the AMF of information used to avoid paging collisions. The base station may include this information in the request for the UE identifier. This information may include the information described in (1) to (15) above. The base station may translate the information described in (1) to (15) above, notified by the UE, into signaling on the N2 interface and notify the AMF. This information may further include information about its own network. This information may be the same as the information described in (1) to (15) above, but with other networks replaced by the AMF's own network. The AMF may use this information about its own network to change the UE identifier. This makes it possible, for example, to prevent paging collisions in the changed UE identifier.

[0227] The AMF may notify the UE of the changed identifier. This notification may use NAS signaling, for example, a Configuration Update Command disclosed in Non-Patent Document 32 (TS24.501). The identifier may be, for example, a 5G-S-TMSI (5G S-Temporary Mobile Subscription Identifier) ​​disclosed in Non-Patent Document 27 (TS23.501). The UE may use this notification to update its UE-ID.

[0228] The UE may notify the AMF that it has completed updating its identifier. This notification may be made using NAS signaling, such as the Configuration Update Complete notification disclosed in Non-Patent Document 32 (TS24.501).

[0229] The AMF may notify the base station of the changed identifier. This notification may be made using signaling on the N2 interface. The base station may use this notification to change the paging timing of the UE. For example, the base station may use the changed identifier of the UE to change the parameters used to determine the paging timing. This can, for example, improve the flexibility of changing the paging timing in the UE. The notification of the changed parameters from the base station to the UE may be in the same manner as described above.

[0230] Figure 15 shows a first example of the assignment of timing priorities for paging from multiple networks and the paging received by the UE. In the example shown in Figure 15, timing priorities are assigned in two stages: high and low. In the example shown in Figure 15, arrow 1500 indicates the DRX period of the UE at network #1, and arrow 1501 indicates the DRX period of the UE at network #2. In the example shown in Figure 15, the paging timing of network #1 is shown in areas 1505-1507, and the paging timing of network #2 is shown in areas 1510-1512. In the example shown in Figure 15, areas 1505, 1507, and 1511, indicated by white squares, are paging timings assigned low timing priority, and areas 1506, 1510, and 1512, indicated by black squares, are paging timings assigned high timing priority.

[0231] In the example shown in Figure 15, the paging timings indicated in regions 1505 and 1510 overlap. In this case, the UE receives paging from NW#2, which has been assigned a higher timing priority, in region 1515. Similarly, the UE receives paging from NW#1 in region 1516 and paging from NW#2 in region 1517.

[0232] Another example of timing priority assignment is that paging timings may be set for each timing priority. For example, each parameter of the PCCH configuration information (PCCH-Config) disclosed in Non-Patent Literature 22 may be determined for each timing priority. A UE may have multiple paging timings in a single paging cycle. In a single UE, if the paging timing of one timing priority overlaps with that of another timing priority, the paging with the higher timing priority may take precedence.

[0233] Figure 16 shows a second example of the assignment of timing priorities for paging from multiple networks and the paging received by the UE. In the example shown in Figure 16, timing priorities are assigned in two stages: high and low. In Figure 16, the UE is configured with high-priority and low-priority paging timings from both Network #1 and Network #2. In Figure 16, elements common to Figure 15 are given the same element numbers, and common explanations are omitted.

[0234] In the example shown in Figure 16, the paging timings with high timing priority allocated by NW#1 are set as areas 1606, 1608, and 1610, while the paging timings with low timing priority allocated by NW#1 are set as areas 1605, 1607, and 1609. In the example shown in Figure 16, the paging timings with high timing priority allocated by NW#2 are set as areas 1615, 1617, and 1619, while the paging timings with low timing priority allocated by NW#2 are set as areas 1616, 1618, and 1620.

[0235] In the example shown in Figure 16, the paging timings shown in regions 1605 and 1615 overlap. In this case, the UE receives paging from NW#2, which is assigned a higher timing priority, in region 1625. Since the paging timings shown in regions 1606 and 1616 do not overlap with any other paging timings, the UE receives paging from NW#1 in region 1626 and paging from NW#2 in region 1627. Similarly, the UE receives paging from NW#2, which is assigned a higher timing priority, in region 1628, receives paging from NW#1 in region 1629, and receives paging from NW#2 in region 1630. Similarly, the UE receives paging from NW#2, which is assigned a higher timing priority, in region 1631, receives paging from NW#1 in region 1632, and receives paging from NW#2 in region 1633.

[0236] The UE may associate timing priorities assigned to one network with timing priorities assigned to other networks. This association may be performed, for example, when the number of timing priority levels in one network differs from the number of timing priority levels in other networks. This allows the UE to compare timing priorities among multiple networks, even when the number of timing priority levels differs among multiple networks.

[0237] The method of this mapping may be defined in the standard. This mapping may be performed, for example, from timing priorities with fewer stages to timing priorities with more stages. For example, in the case of two-stage and three-stage timing priorities, high and low in the two-stage timing priority may be mapped to high and low in the three-stage timing priority, respectively. This makes it possible to avoid complexity in the mapping, for example.

[0238] As another example, this mapping may be performed from timing priorities with more stages to timing priorities with fewer stages. For example, in cases with two or three stages, the high, medium, and low stages in the three-stage timing priority system may be mapped to the high, high, and low stages in the two-stage timing priority system, respectively. This allows for increased flexibility in the mapping, for example.

[0239] Other solutions are disclosed. Assign the types of paging that can be transmitted to each timing priority. For example, if there are two timing priority levels, all types of paging may be transmitted for high timing priority paging, and all types of paging except emergency communication may be transmitted for low timing priority paging. Another example is if there are three timing priority levels: high, medium, and low. All types of paging may be transmitted for high timing priority paging, all types of paging except emergency communication may be transmitted for medium timing priority paging, and all types of paging except emergency communication, voice calls, and SI updates may be transmitted for low timing priority paging. The method disclosed in Embodiment 1 may be used for assigning timing priorities. The operation of the UE may be the same as the operation disclosed in Embodiment 1. This eliminates the need to assign type priorities, and as a result, the processing load on the NW-side equipment of the communication system can be reduced.

[0240] As another example, all paging types may be made transmittable regardless of timing priority. This allows for, for example, the rapid reception of paging with a predetermined timing priority if paging with a predetermined timing priority cannot be received due to a timing conflict with paging with an even higher timing priority from another network.

[0241] Other solutions are disclosed. A transmission timing priority may be set for each paging type. If there are two timing priority levels, emergency communications may be transmitted only on high-priority paging, while other types of paging may be transmitted on both high and low-priority paging. As another example, if there are three timing priority levels (high, medium, and low), emergency communications may be transmitted only on high-priority paging, voice calls and SI updates may be transmitted on high or medium-priority paging, while other types of paging may be transmitted on any of the high, medium, or low-priority paging. The method disclosed in Embodiment 1 may be used for assigning timing priorities. The operation of the UE may be the same as the operation disclosed in Embodiment 1. This eliminates the need for assigning type priorities, and as a result, the processing load on the NW-side equipment of the communication system can be reduced.

[0242] As another example, all types of paging may be made transmittable at all timing priorities. This allows for, for example, the rapid reception of a given type of paging when a paging with a given timing priority cannot be received due to a timing conflict with a paging with an even higher timing priority from another network.

[0243] The method disclosed in Embodiment 1 may be used when connections to multiple networks are active, for example, when the RRC state between the base stations of multiple networks is RRC_CONNECTED. The method disclosed in Embodiment 1 may be used when only one network is active and connections to other networks are inactive, for example, when the RRC state between the base station of one network is RRC_CONNECTED and the RRC state between the base stations of other networks is RRC_INACTIVE or RRC_IDLE. The method disclosed in Embodiment 1 may be used when connections to multiple networks are inactive, for example, when the RRC state between the base stations of multiple networks is RRC_INACTIVE or RRC_IDLE. The UE may switch the network to which it is connected when receiving paging. By doing so, the UE may notify the base station of the source network of information regarding the connection switch. The base station of the source network may use this information to stop scheduling for the UE. This allows for, for example, more efficient use of wireless resources at the base station of the source network.

[0244] This embodiment 1 makes it possible to reduce the possibility that the UE will not receive emergency communication paging due to a conflict between the timing of emergency communication paging and the timing of paging of other networks.

[0245] Modification 1 of Embodiment 1. Embodiment 1 disclosed a method by which the UE prioritizes receiving paging with a higher timing priority. This Modification 1 discloses a method relating to the UE's receiving behavior when the timings of paging with the same timing priority conflict.

[0246] The UE may receive paging from a base station with good communication quality. This can, for example, improve the reliability of paging reception.

[0247] The UE may use the synchronization signal transmitted from the base station, CSI-RS, PDCCH, or DM-RS to determine the communication quality. The DM-RS may be the DM-RS of PDCCH, the DM-RS of PDSCH, or the DM-RS of PBCH.

[0248] As another example, the UE may prioritize receiving paging from the base station with the less frequent paging timing. In determining which base station has the less frequent paging timing, the UE may use the DRX period, the number of PFs in the DRX cycle, the number of POs in the PF, or the number of PDCCH monitoring occasions in the PO. A combination of several of the above may also be used. As yet another example, the UE may prioritize receiving paging from the base station with the longer time until the next paging timing. This can, for example, reduce latency in paging reception.

[0249] As another example, the UE may receive paging from a different network than the one from which it previously received paging. For example, if paging with the same timing priority conflicts, the UE may sequentially switch the network from which it receives paging. That is, the network from which the UE receives paging may be determined using round-robin. The method described above may be used, for example, when paging from multiple networks conflicts at the same time. This prevents a situation where, for example, paging from a particular network cannot be received for an extended period.

[0250] As another example, the UE may use the fact that paging occurred at the time of the receiving paging operation to switch the receiving paging network. This switching may, for example, involve sequentially switching between multiple networks. For example, the aforementioned round-robin method may be used for this switching. This allows the UE to receive paging from multiple networks even if, for example, the timing of actual paging transmissions from multiple networks overlap.

[0251] As another example, a UE may have parameters related to receiving paging from multiple networks. These parameters may be set for each network to which the UE is connected, for each paging timing from the same network, or a combination of both. The parameters may, for example, have a value that increases over time. The parameters may be decremented or initialized when the UE performs a paging reception operation from a network. The parameters may be decremented or initialized when the UE actually receives paging from a network. The decremented value may be a constant value, may differ for each timing priority, may differ for each type of paging actually received, or may differ between when the UE performs a reception operation and when the UE actually receives the paging. The UE may perform a paging reception operation from the network with the highest value of the parameter. When the value of the parameter is the same across multiple networks, it may be predetermined which network's paging reception operation the UE will perform. This allows for improved flexibility in paging reception from multiple networks within a UE, for example.

[0252] As another example, a UE may have a timer for receiving paging from multiple networks. This timer may be set for each network to which the UE is connected, for each paging timing from the same network, or a combination of both. The timer may start, for example, when the UE registers with the network (e.g., when RM_REGISTERED is reached). The timer may stop or be initialized when the UE performs a paging reception operation from the network. The parameter may stop or be initialized when the UE actually receives paging from the network. The UE may perform a paging reception operation from the network with the shortest remaining time on the timer, or from the network whose timer expires first. The initial value of the timer may be constant across multiple networks or may differ for each network. The initial value of the timer may be determined by a standard, or it may be determined and notified to the UE by the equipment in each network (e.g., AMF, PCF, UPF, SMF, base station). This, for example, yields the same effect as described above.

[0253] The UE may notify the base station of the aforementioned parameters or the aforementioned timers. The base station may use this information to decide whether or not to transmit paging at a predetermined paging timing, or to decide the type of paging at a predetermined paging timing. For example, the base station may decide not to transmit paging at a given paging timing if the value of the parameter for its own network is the second highest or lower among the networks. This can, for example, reduce power consumption in the communication system.

[0254] As another example, the UE may receive paging from a preceding paging timing. The UE may perform this action, for example, when some of the paging timings from multiple networks overlap. This allows for, for example, rapid paging reception by the UE.

[0255] As another example, the UE may make the determination using the type of NW. The type of NW may be, for example, a PLMN or a private NW (or a non-public NW). The UE may, for example, preferentially receive paging from the base station on the PLMN side. As a result, for example, the UE can quickly receive an emergency notification from the PLMN. As another example, the UE may preferentially receive paging from the base station on the private NW side. As a result, for example, the UE can quickly receive downlink data generated within the private NW.

[0256] A primary NW and a secondary NW may be provided. The multi-SIM UE may set the primary NW or the secondary NW. The UE may make the setting regarding the primary NW and / or the secondary NW to the base station of the primary NW and / or the AMF, or to the base station of the secondary NW and / or the AMF. As a result, in the design of the communication system, it is possible to avoid the complexity of the process for notifying information regarding paging collision.

[0257] A person may set the primary NW and / or the secondary NW for the UE. For example, the primary NW and the secondary NW are set according to the person's preference. As a result, it is possible to implement paging collision avoidance for the NW preferred by the person. The UE may store the setting of the primary NW and / or the secondary NW in advance. The UE can use the setting of the primary NW and / or the secondary NW at any time.

[0258] The UE may receive paging from the base station of the primary NW. As a result, for example, it is possible to reduce the processing amount in the UE.

[0259] For each timing priority disclosed in Embodiment 1, it may be determined which paging from which NW is preferentially received. For example, when two levels of timing priority are provided, for paging with a high timing priority, paging from the base station on the PLMN side may be preferentially received, and for paging with a low timing priority, paging from the base station on the private NW side may be preferentially received. As a result, for example, the UE can quickly receive an emergency notification from the PLMN and can also quickly receive downlink data generated within the private NW.

[0260] The UE may determine the NW from which to preferentially receive paging in a manner different from the above. As a result, for example, flexible execution of the paging reception operation in the UE becomes possible.

[0261] The UE may notify the base station of which base station's paging from which NW is to be preferentially received. As another example, the UE may notify the base station that it will not receive paging from the base station. The notified base station may be the base station from which the UE does not receive paging. The base station may use this notification to change the assignment of timing priority or change the paging timing. The base station may notify the UE of the changed timing priority assignment or the changed paging timing. The notification from the base station to the UE may be performed, for example, using the method disclosed in Embodiment 1. As a result, for example, it is possible to prevent the paging received by the UE from being biased towards the base station of a specific NW. As another example, the notified base station may be the base station from which the UE receives paging. The UE may notify the base station from which it receives paging that it will receive paging. The base station may use this notification to determine the paging assignment at each paging timing. As a result, for example, it is possible to improve the efficiency of paging notification in the communication system.

[0262] The UE may notify the base stations after obtaining information regarding paging timing from each base station of the connected network. Alternatively, the UE may notify the base stations after obtaining information regarding timing priority for paging timing from each base station of the connected network. Alternatively, the UE may notify the base stations after obtaining both of the aforementioned pieces of information.

[0263] As another example, a UE may notify a base station if it switches which network base station it prioritizes receiving paging from, for example, if the communication quality with the base station that is not receiving exceeds the communication quality with the base station that is receiving. This communication quality may be, for example, the synchronization signal from the base station and / or the RSRP, RSRQ, SINR, or received power of the CSI-RS. In the aforementioned case, the UE may include this notification to the base station in the measurement report. This allows, for example, a base station with degraded communication quality to use the paging timing for communication with other UEs, thereby improving communication efficiency.

[0264] The information provided by the UE to the base station regarding which network base station's paging should be prioritized for reception may be similar to the information disclosed in Embodiment 1 as examples of information regarding unreceived paging, such as (1) to (15). This information may also include information regarding collisions with the same timing priority.

[0265] The aforementioned notification from the UE to the base station may include a request for a change in paging timing. The base station may use this request to change the paging timing. The change in paging timing at the base station, the notification or broadcast of the paging timing change from the base station to the UE, and / or the actions at the UE may be similar to, for example, the method disclosed in Embodiment 1.

[0266] As another example, a base station may decide which network base station the UE will prioritize receiving paging from. The base station may make this decision, for example, using measurement reports from the UE, using the network type (e.g., PLMN, private network), or by prioritizing the base station on the primary network side.

[0267] The base station making the decision may, for example, be a base station on the primary network side. This allows for, for example, avoidance of control complexity in the communication system. As another example, the base station making the decision may be a base station with good communication quality with the UE. This allows for, for example, improvement of the quality of control from the base station to the UE. As yet another example, the base station making the decision may be a base station whose RRC connection state with the UE is RRC_CONNECTED. This allows for, for example, avoidance of control complexity in the communication system.

[0268] The base station may notify the UE which network base station's paging should be given priority. The UE may use this notification to process overlapping paging receptions.

[0269] The notification from the base station to the UE may be made using RRC signaling, for example, signaling for RRC connection reconfiguration. This allows the base station to notify the UE of more information, for example. As another example, the notification from the base station to the UE may be made using MAC signaling. This allows the base station to notify the UE of the information more quickly, for example. As yet another example, the notification from the base station to the UE may be made using L1 / L2 signaling. This allows the base station to notify the UE of the information even more quickly, for example.

[0270] As another example, the core network may determine which network base station the UE will prioritize receiving paging from. The core network may be, for example, an AMF, an SMF, or a PCF. The core network device may make this determination using, for example, the network type (e.g., PLMN, private network), or it may prioritize base stations on the primary network side.

[0271] The core network device making the decision may, for example, be a device on the primary network side. This makes it possible to avoid control complexity in the communication system, for example. As another example, the core network device making the decision may be the core network device of a network at a base station with good communication quality with the UE. This makes it possible to improve the quality of control from the base station to the UE, for example. As yet another example, the core network device making the decision may be the core network device of a network at a base station where the RRC connection state with the UE is RRC_CONNECTED. This makes it possible to avoid control complexity in the communication system, for example. As yet another example, the core network device making the decision may be the core network device of a network where the connection state with the UE is CM_CONNECTED. This makes it possible to avoid control complexity in the communication system, for example.

[0272] The core network device may notify the UE which network base station's paging should be given priority. The UE may use this notification to process overlapping paging receptions.

[0273] The notification from the core network device to the UE may be made using NAS signaling. This allows the core network device to notify the UE of a large amount of information. As another example, the notification from the core network device to the UE may be made via a base station. The notification from the base station to the UE may be made using RRC signaling, for example, RRC connection reconfiguration signaling. This allows the core network device to notify the UE of a large amount of information. As yet another example, the notification from the base station to the UE may be made using MAC signaling. This allows the base station to notify the UE of the information more quickly. As yet another example, the notification from the base station to the UE may be made using L1 / L2 signaling. This allows the base station to notify the UE of the information even more quickly.

[0274] The method disclosed in this modified example 1 may be applied even when timing priorities are not set. This allows the UE to quickly determine which network is receiving paging, for example, even when no timing priorities are set for paging.

[0275] This modified version 1 allows the base station and / or core network equipment to know which network the UE will prioritize receiving paging from. As a result, malfunctions in the communication system can be prevented.

[0276] Modification 2 of Embodiment 1. A UE equipped with multiple SIMs transmits and receives data with multiple networks. Therefore, for example, if all of the UE's connections are to PLMNs, the UE may receive the same emergency communication from multiple PLMNs. This can lead to a problem where the UE's memory size becomes strained.

[0277] This modified example 2 discloses a method for solving the aforementioned problem.

[0278] The UE deletes paging of the same type. The UE may keep only the first paging it receives. The UE may delete paging that is received later. For example, the UE may delete the data related to later received paging, or it may not receive such data at all.

[0279] The operation in the UE may be applied only to a predetermined type of paging. For example, the operation in the UE may be applied to emergency communications. Such emergency communications may be, for example, a PWS (Public Warning System), an ETWS (Earthquake and Tsunami Warning System), a CMAS (Commercial Mobile Alert System), an EU-ALERT (European Public Warning System), or a KPAS (Korean Public Alert System). Such emergency communications may be, for example, emergency communications for private networks disclosed in Embodiment 1. Such emergency communications may be other types of emergency communications. This makes it possible, for example, to prevent the UE from mistakenly deleting data with different contents as if it were the same data.

[0280] The UE may use information regarding the paging type to determine whether there is a duplicate. This information may be, for example, information included in the paging or information included in the data related to the paging. This information may be, for example, a Message Identifier disclosed in section 9.4.1.2.2 of Non-Patent Document 21 (TS23.041 V16.2.0).

[0281] Paging may include information about the source. For example, paging for an emergency communication may include information about the source of the emergency communication. The information about the source may be uniquely assigned regardless of the PLMN, or may be assigned by each PLMN. When each PLMN assigns information about the source, each PLMN may notify the UE of the information about the assignment to the source. This notification to the UE may be performed, for example, by the AMF. The UE may use the information about the source to determine whether there is a duplication. This can prevent, for example, accidentally detecting duplication of data from different sources.

[0282] Paging may include information about a serial number. The serial number may be unique, for example, among the aforementioned sources. The UE may use the information about the serial number to determine whether there is a duplication. This can prevent, for example, accidentally detecting duplication of different data from the same source.

[0283] The UE may determine that paging of a predetermined type received within a predetermined time difference is paging related to the same data. For example, when the UE receives paging for an emergency communication from base stations of a plurality of NWs within a predetermined time difference, the UE may determine that the emergency communications have the same content. This enables the UE to determine that the emergency communications have the same content even when the UE receives emergency communications of the same content from a plurality of NWs at different timings.

[0284] The predetermined time difference may be defined in advance, or may be determined by the core NW and notified to the UE, or may be determined by the base station and notified to the UE.

[0285] The base station making the decision may be, for example, a base station on the primary network side, similar to Modification 1 of Embodiment 1. This makes it possible to avoid control complexity in the communication system, for example. As another example, the base station making the decision may be a base station with good communication quality with the UE. This makes it possible to improve the quality of control from the base station to the UE, for example. As yet another example, the base station making the decision may be a base station whose RRC connection state with the UE is RRC_CONNECTED. This makes it possible to avoid control complexity in the communication system, for example.

[0286] Similar to Modification 1 of Embodiment 1, the core network may be, for example, an AMF, an SMF, or a PCF. The core network device may make the decision using, for example, the network type (e.g., PLMN, private network), or it may prioritize the base station on the primary network side.

[0287] The core NW device that makes the decision may be, for example, a device on the primary NW side, similar to Modification 1 of Embodiment 1. This makes it possible to avoid control complexity in the communication system, for example. As another example, the core NW device that makes the decision may be the core NW device of a base station NW with good communication quality with the UE. This makes it possible to improve the quality of control from the base station to the UE, for example. As yet another example, the core NW device that makes the decision may be the core NW device of a base station NW where the RRC connection state with the UE is RRC_CONNECTED. This makes it possible to avoid control complexity in the communication system, for example. As yet another example, the core NW device that makes the decision may be the core NW device of a NW where the connection state with the UE is CM_CONNECTED. This makes it possible to avoid control complexity in the communication system, for example.

[0288] The predetermined time difference may be determined by multiple networks, for example, multiple core network devices. Alternatively, the predetermined time difference may be determined by multiple base stations. The predetermined time difference may differ among multiple networks, or among multiple base stations. The UE may use the shorter of the different times among the multiple networks and / or base stations. This prevents, for example, the UE from mistakenly deleting different data as the same data. As another example, the UE may use the longer of the different times among the multiple networks and / or base stations. This prevents, for example, the UE from mistakenly detecting the same data as different data, and as a result, the processing load on the UE can be reduced.

[0289] The predetermined time difference may be set for each type of paging. This can, for example, improve the flexibility of a communication system.

[0290] The operation in the UE may be applied when the same PLMN is used. That is, the operation in the UE may not be applied when the UEs are connected to different PLMNs. This prevents the UE from mistakenly detecting different paging types as the same paging type when different paging types are set for the same message identifier (see Non-Patent Document 21 (TS23.041 V16.2.0)) in each NW.

[0291] This operation in the UE may also be applied to the private network. This allows the UE to detect duplicate emergency communications for the private network with the same content, thereby reducing the processing load on the UE.

[0292] As another example, this operation in the UE may apply when it is the same private network. This prevents the UE from mistakenly identifying different paging types as the same paging type when different paging types are set for the same message identifier (see Non-Patent Document 21 (TS23.041 V16.2.0)) in each network.

[0293] Information regarding the assignment of message identifiers to paging types (see Non-Patent Literature 21 (TS23.041 V16.2.0)) in each network may be notified to the UE. For example, NAS signaling may be used for this notification. The UE may use this notification to detect paging of the same content. This allows the UE to detect paging of the same type even if different message identifiers are assigned to the same paging type in different networks.

[0294] This modified version 2 makes it possible to avoid receiving duplicate paging, and as a result, it is possible to reduce the amount of processing load in the UE.

[0295] Embodiment 2. A UE equipped with multiple SIMs may maintain RRC connections with base stations of multiple networks. The UE may also perform time-division multiplexing transmission and reception with each of the base stations of the multiple networks.

[0296] The following problem arises in the aforementioned operation. For example, when the UE switches the transmission / reception destination from the original network base station (sometimes referred to as base station #1) to another network base station (sometimes referred to as base station #2), and transmits and receives data with base station #2, the UE maintains the RRC state with base station #1 as RRC_CONNECTED, but is unable to receive signals from base station #1. In this case, if the UE detects a loss of synchronization with base station #1, and as a result detects an RLF (Relational Limit Failure) with base station #1, the UE will need to reconnect with base station #1.

[0297] This second embodiment discloses a method for solving the aforementioned problems.

[0298] The UE stops the timers and / or counters (hereinafter sometimes referred to as RLF timers) used for RLF detection with base station #1. The stopping of the RLF timers in the UE may occur when the UE switches the transmission / reception destination from base station #1 to base station #2. The RLF timers may be, for example, T310, N310, N311, or a combination of several of the above disclosed in Non-Patent Document 22 (TS38.331).

[0299] The UE may notify base station #1 to switch the transmission / reception destination, or to stop the RLF timers for base station #1. Base station #1 may use this notification to refrain from scheduling for the UE. This can, for example, improve the communication efficiency at base station #1.

[0300] The base station may have a timer. This timer may be, for example, a timer that manages the activity of the UE (hereinafter sometimes referred to as an inactivity timer). For example, this timer may advance while no transmission or reception is taking place between the base station and the UE. This timer may stop or reset when transmission or reception takes place between the base station and the UE. When the timer expires, the base station may instruct the UE to release the RRC connection or to interrupt the RRC connection.

[0301] Base station #1 may use the notification from the UE to stop the inactivity timer. This prevents the timer from running, for example, when the UE's connection destination switches from base station #1 to base station #2. As a result, it prevents the base station from deciding to interrupt the UE's RRC connection while the switchover is taking place.

[0302] The stopping of RLF timers in the UE may be performed before, after, or simultaneously with the notification to base station #1. For example, stopping the RLF timers before the notification can reduce the amount of memory used by the UE when switching between transmit and receive destinations. Alternatively, stopping the RLF timers after the notification can reduce the amount of processing required when the UE sends a notification to base station #1. Furthermore, stopping the RLF timers simultaneously with the notification can avoid complexity in managing these timers in the UE.

[0303] The notification from the UE to base station #1 may be made dynamically. For example, L1 / L2 signaling may be used for the notification. This allows for rapid switching of the transmission / reception destination, for example, when uplink data is generated from the UE to base station #2. As another example, MAC signaling may be used for the notification. This allows for the notification of more information through uplink transmission of higher modulation orders, and improves reliability through retransmission control.

[0304] As another example, the notification from the UE to base station #1 may be made quasi-statically. For example, RRC signaling may be used for the notification. New RRC signaling may be established for the notification. This eliminates the need for the UE to make the notification each time the destination is switched. As a result, the amount of signaling between the UE and the base station can be reduced.

[0305] As another example, the destination switching at the UE may be predetermined by the base station and notified to the UE. The UE may use this notification to determine the destination base station. The base station that sends this notification to the UE may be predetermined, for example. For example, this information may be included in the UE's SIM. This makes it possible to reduce the amount of signaling between the UE and the base station, for example.

[0306] The UE may establish downlink synchronization with base station #2. The UE may establish downlink synchronization using a synchronization signal from base station #2 (e.g., an SS block), or using another signal, such as CSI-RS from base station #2. The establishment of downlink synchronization with base station #2 by the UE may be performed, for example, after the RLF timers for base station #1 have been stopped. This prevents, for example, the RLF timers for base station #1 from expiring while the UE is receiving downlink signals from base station #2. As another example, the establishment of downlink synchronization with base station #2 by the UE may be performed after notifying base station #1 of the destination switch. This eliminates the need for scheduling from base station #1 to the UE while the UE is performing the downlink synchronization establishment operation, resulting in improved communication efficiency at base station #1.

[0307] As another example, the UE may maintain information regarding frame timing at both base stations #1 and #2. For example, the UE may maintain information regarding the frame offset between base station #1 and base station #2. The UE may acquire each of the aforementioned pieces of information when establishing an RRC connection with base stations #1 and #2, respectively. The UE may update each of the aforementioned pieces of information. The UE may perform such updates at predetermined intervals or when some event occurs. When the UE maintains each of the aforementioned pieces of information, it may choose not to perform a downlink synchronization establishment operation with base station #2. This allows for, for example, rapid transmission and reception switching between base stations #1 and #2.

[0308] The UE starts or restarts timers and / or counters (hereinafter sometimes referred to as RLF timers) used for RLF detection between it and base station #2. The UE may start or restart the RLF timers after it has switched its transmission / reception destination from base station #1 to base station #2, for example, after the random access process between the UE and base station #2 is completed.

[0309] The random access may consist of two steps, for example, a PRACH transmission from the UE to the base station and an RA response from the base station to the UE, or it may consist of four steps. The UE may start or restart RLF timers after receiving the RA response from the base station, or after receiving the fourth step response from the base station. After the random access is complete, the base station may start a timer for the UE, such as an inactivity timer, or restart it without initialization. This avoids complexity related to the control of RLF timers in the UE and / or inactivity timers in the base station.

[0310] The UE may choose not to perform random access processing with base station #2. The UE may choose not to perform the aforementioned random access processing if, for example, it is able to maintain uplink synchronization with base station #2. The UE being able to maintain uplink synchronization with base station #2 may, for example, mean that a predetermined amount of time has not elapsed since transmission and reception between the UE and base station #2 stopped, or that the UE's position is within a predetermined range, or that the UE's speed is within a predetermined range. This allows, for example, a rapid resumption of transmission and reception between the UE and base station #2.

[0311] The UE may notify base station #2 that the transmission / reception destination has switched to base station #2, or it may notify base station #2 of the restart of RLF timers. This notification from the UE to base station #2 may occur, for example, when no random access is performed between the UE and base station #2. This notification may be made using L1 / L2 signaling. This allows the UE to quickly notify base station #2 of the transmission / reception destination switch. As another example, this notification may be made using MAC signaling. This allows for improved reliability through retransmission control, for example. As yet another example, this notification may be made using RRC signaling. This allows the UE to notify the base station of more information, for example. The base station may use this notification to start an inactivity timer for the UE, or restart it without initialization. This allows for avoidance of complexity related to the control of inactivity timers at the base station, for example.

[0312] When restarting RLF timers, the RLF timers may be initialized. This avoids complexity in the UE design. Alternatively, the RLF timers may not be initialized, i.e., they may be restarted from their values ​​at the time of the stop. This allows the UE to quickly detect an RLF, for example, if an actual out-of-sync event occurs between the UE and base station #2, and as a result, enables a rapid recovery from the RLF.

[0313] Figure 17 is a sequence diagram showing an example of the stopping and restarting of RLF timers when the UE switches its transmit / receive destination. In Figure 17, the UE is connected to base station #1 under NW#1 and base station #2 under NW#2.

[0314] In step ST1703 shown in Figure 17, the UE is in the RRC_CONNECTED state for the connection between gNB#1 and gNB#2. In step ST1705, data is transmitted and received between the UE and gNB#1.

[0315] In step ST1707 shown in Figure 17, data is generated from the UE for gNB#2. In step ST1709, the UE notifies gNB#1 that it will switch its connection destination to gNB#2. The notification in step ST1709 may be made by L1 / L2 signaling, MAC signaling, or RRC signaling. gNB#1 uses the notification in step ST1709 to stop scheduling for the UE. In step ST1711, the UE stops the RLF timers for gNB#1. The RLF timers may be, for example, T310, N310, or N311 as disclosed in Non-Patent Literature 22 (TS38.331), or a combination of several of the above.

[0316] In step ST1713 shown in Figure 17, gNB#2 sends an SS block to the UE. In step ST1715, the UE establishes downlink synchronization with gNB#2 upon receiving the SS block from step ST1713.

[0317] In step ST1717 shown in Figure 17, random access processing is performed between the UE and gNB#2. The random access processing in step ST1717 may consist of two steps: a PRACH transmission from the UE to gNB#2 and an RA response from gNB#2 to the UE. This allows for, for example, rapid completion of the random access processing between the UE and gNB#2. In step ST1719, the UE restarts the RLF timers for gNB#2. In this restart, the RLF timers for gNB#2 may be initialized. Step ST1719 may be performed upon completion of step ST1717. The RLF timers for gNB#2 may be the same as those for gNB#1 that were stopped in step ST1711. In step ST1721, data transmission and reception occur between the UE and gNB#2.

[0318] In Figure 17, after step ST1721 is completed, the UE's connection destination switches from gNB#2 to gNB#1. In step ST1723, the UE notifies gNB#2 that it will switch its UE's connection destination to gNB#1. The same signaling as in step ST1709 may be used for the notification in step ST1723. In step ST1731, the UE stops the RLF timers for gNB#2. In step ST1733, gNB#1 sends an SS block to the UE. In step ST1735, upon receiving the SS block in step ST1733, the UE establishes downlink synchronization with gNB#1.

[0319] In step ST1737 shown in Figure 17, random access processing is performed between the UE and gNB#1. The random access processing in step ST1737 may be the same as that in step ST1717. In step ST1739, the UE restarts the RLF timers for gNB#1. The RLF timers for gNB#1 may be initialized during this restart. In step ST1741, data is transmitted and received between the UE and gNB#1.

[0320] Figure 17 shows the case where the random access in steps ST1717 and ST1737 consists of two steps, but a four-step random access process may also be used. When a four-step random access is used, the base station may reset the RRC parameters to the UE. This allows for, for example, improved flexibility in the communication system.

[0321] Other solutions are disclosed. The UE may choose not to stop the RLF timers for base station #1. The UE may choose not to perform RLF processing after the RLF timers for base station #1 have expired. This RLF processing may be, for example, a transition to RRC_IDLE, or the processing disclosed in section 5.3.10.3 of Non-Patent Literature 22 (TS38.331), or a combination of both. This allows for, for example, avoidance of complexity in the control of RLF timers in the UE.

[0322] In the aforementioned case, after the UE's transmission and reception destination switches back to base station #1, the UE should initialize the timers related to base station #1. This prevents, for example, false detection of the RLF when the UE's transmission and reception destination switches back to base station #1.

[0323] Other solutions are disclosed. The UE may detect RLF with base station #1 when the transmission / reception destination switches from base station #1 to base station #2. Some RLF processing with base station #1 may be omitted. For example, the UE may not transition to RRC_IDLE. In the RRC re-establishment operation disclosed in section 5.3.7 of Non-Patent Literature 22 (TS38.331), the radio bearer may not be stopped. The MAC may not be reset. The SCell of the MCG (Master Cell Group) may not be released. spCellcConfig may not be released. DC may not be released. p-NR-FR1 may not be released. p-UE-FR1 may not be released. delayBudgetReportingConfig may not be released. T342 may not be stopped. overheatingAssistanceConfig may not be released. T345 may not be stopped.

[0324] The UE may perform cell selection. A timer related to cell selection (e.g., T311) disclosed in Non-Patent Literature 22 (TS38.331) may be started. This allows for, for example, avoidance of complexity in the cell selection process. Alternatively, the UE may choose not to start T311. This prevents, for example, the RRC_IDLE transition that occurs upon the expiration of T311.

[0325] The UE may maintain the RRC parameters. This maintenance action in the UE may be applied, for example, when the UE selects the same cell as before RLF detection. This can reduce the processing load associated with re-establishing the RRC connection, for example. Alternatively, the UE may release the RRC parameters. This release action in the UE may be applied, for example, when the UE selects a different cell than the one before RLF detection. This can improve the flexibility of the communication system, for example.

[0326] The method disclosed in this second embodiment may also be applied to beam failures. For example, the timer and / or counter associated with the number of beam failure instance indications and / or beam failure instance indications, as disclosed in section 9.2.8 of Non-Patent Document 16 (TS38.300), may be stopped and restarted when the UE switches between transmit and receive destinations. The timer and / or counter may be, for example, the beamFailureRecoveryTimer disclosed in Non-Patent Document 17 (TS38.321), the beamFailureDetectionTimer, or the BFI_COUNTER. This makes it possible to prevent false detection of beam failures when the UE switches between transmit and receive destinations.

[0327] In applying the method disclosed in Embodiment 2, the switching of the transmission / reception destination may not occur until the random access response is received. As another example, the switching of the transmission / reception destination may not occur until message 4 is received in the random access processing. The above operation may be applied, for example, when the UE transmits PRACH to the base station. This makes it possible to prevent, for example, the failure of the random access processing.

[0328] In applying the method disclosed in Embodiment 2, the connection between the UE and the base station's network before destination switching (e.g., NAS connection) may be maintained. This allows, for example, rapid reconnection with the base station's network. Alternatively, the connection between the UE and the network may be released. This allows, for example, a reduction in memory usage in the UE.

[0329] The method disclosed in Embodiment 2 may be applied to beam management and / or beam measurement. For example, the UE may include information indicating that the beam could not be measured in the measurement report to the base station. This notification from the UE to the base station may occur, for example, when the UE switches the transmission / reception destination to a base station on another network. The UE may include information in the notification regarding the reason why the measurement could not be performed. This reason may be, for example, a switch in the transmission / reception destination. The base station may use this information for beam control to the UE. This prevents, for example, the base station from mistakenly determining that the quality of the beam used with the UE is poor.

[0330] The method disclosed in this second embodiment may also be used in random access processing. For example, when the destination base station of a UE switches from gNB#1 to gNB#2, the collision resolution timer for gNB#1, such as the ra-ContentionResolutionTimer disclosed in Non-Patent Literature 17 (TS38.321), may be stopped. This makes it possible to prevent false detection of collisions in random access processing after the destination base station has switched.

[0331] When the destination base station of a UE switches from gNB#1 to gNB#2, the collision resolution timer for gNB#1 may be started or restarted. The aforementioned start or restart may be performed from an initial value. This allows for, for example, avoidance of complexity in the UE's management of the timer. As another example, the collision resolution timer may be restarted from a value after it was stopped. This allows, for example, the UE to quickly detect random access collisions.

[0332] In this second embodiment, the case where the UE is connected to base stations #1 and #2 was disclosed, but the number of base stations to which the UE is connected may be three or more. For example, the method disclosed in this second embodiment may be used to switch the transmission / reception destination from base station #1 to base station #3. Also, for example, the method disclosed in this second embodiment may be used to switch the transmission / reception destination from base station #3 to base station #4. This allows for flexible execution of switching between transmission / reception destination base stations by the UE.

[0333] The method disclosed in this second embodiment may be used in MAC processing. For example, when the destination base station of the UE switches from gNB#1 to gNB#2, a timer that manages the operating state of the SCell for gNB#1 (e.g., the SCellDeactivationTimer disclosed in Non-Patent Literature 17 (TS38.321)) may be stopped. The timer may be restarted when the destination base station of the UE switches back to gNB#1. This makes it possible to prevent the timer from expiring after the destination base station of the UE switches from gNB#1 to gNB#2. As a result, the amount of processing required for the reactivation of the SCell in the UE can be reduced.

[0334] The aforementioned operation may also be applied to a timer that manages the operating state of the BandWidth Part (BWP) for gNB#1 (for example, the bwp-InactivityTimer disclosed in Non-Patent Document 17 (TS38.321)). This makes it possible to reduce the amount of processing required for the reactivation of the BWP in the UE, for example, as described above.

[0335] The aforementioned operation may also be applied to a timer that manages data conduction activity for gNB#1 (e.g., the dataInactivitiTimer disclosed in Non-Patent Document 17 (TS38.321)). This makes it possible to prevent the UE from transitioning to RRC_IDLE, for example, as described above.

[0336] The method disclosed in this second embodiment may also be used in RLC processing. For example, the above operation may be applied to a timer used for the reassembly process of the RLC PDU for gNB#1 (e.g., t-Reassembly disclosed in Non-Patent Literature 29 (TS38.322)). This makes it possible to reduce the number of status checks in RLC (e.g., RLC STATUS PDU transmission) as described above.

[0337] The method disclosed in Embodiment 2 may be used in PDCP processing. For example, the above operation may be applied to a timer used to manage the discarding of PDCP SDUs for gNB#1 (e.g., the discardTimer disclosed in Non-Patent Document 30 (TS38.323)). This makes it possible to prevent the discarding of PDCP SDUs, as described above. As a result, packet loss in the communication system can be prevented.

[0338] The aforementioned operation may also be applied to the timer used for PDCP reordering control (for example, t-Reordering disclosed in Non-Patent Document 30 (TS38.323)). This makes it possible to prevent the transmission of received data in the middle of reordering to a higher layer, as described above. As a result, the reordering process in the higher layer can be reduced.

[0339] This second embodiment makes it possible to prevent the RLF timers related to the connection with the original network base station from expiring while a UE with multiple SIMs is transmitting and receiving data with a base station of another network. As a result, it becomes unnecessary to re-establish the RRC connection with the original network base station.

[0340] Embodiment 3. A survival time (see Non-Patent Document 23 (TR22.832 V17.1.0)), which indicates the allowable communication interruption time until the application layer is interrupted when a communication failure occurs, may be used for QoS control in a network.

[0341] However, the method for QoS control using survival time has not been disclosed. As a result, the network cannot control communication using survival time, and thus the network cannot perform communication that meets the requirements of the application layer.

[0342] This third embodiment discloses a method for solving the aforementioned problems.

[0343] QoS parameters related to survival time are established. The network-side device may notify the UE of the QoS parameters related to survival time. The QoS parameters notified by the network-side device to the UE may be QoS parameters related to survival time in downlink communication. The UE may notify the network-side device of the QoS parameters related to survival time. The QoS parameters notified by the UE to the network-side device may be QoS parameters related to survival time in uplink communication.

[0344] Examples of QoS parameters related to survival time are disclosed below (1) to (16).

[0345] (1) Survival time value.

[0346] (2) MTBF (Mean Time Between Failure).

[0347] (3) MTTR (Mean Time To Repair).

[0348] (4) MUT (Mean Up Time).

[0349] (5) MDT (Mean Down Time).

[0350] (6) Intrinsic availability.

[0351] (7) Operational availability.

[0352] (8) Allowable latency.

[0353] (9) The number of times latency is allowed to exceed the limit.

[0354] (10) The number of consecutive times latency is allowed.

[0355] (11) The number of times communication failures are permitted.

[0356] (12) The number of consecutive times communication failures are permitted.

[0357] (13) The period of communication.

[0358] (14) RLC layer retention volume.

[0359] (15) PDCP layer retention amount.

[0360] (16) A combination of the above (1) to (15).

[0361] Regarding (1) above, for example, core network equipment, base stations, and / or UEs may use the survival time value itself for QoS control. For example, the survival time requirement may be added to the 5QI table described in Non-Patent Document 27 (TS23.501). This would, for example, allow for the avoidance of complexity in QoS control using survival time.

[0362] The value in (2) above may be calculated, for example, by treating the expiration of the survival time timer as a failure. The core network equipment, base stations, and / or UEs may use the value in (2) above to configure the communication path between the base station and the UE. This makes it possible to avoid complexity in controlling the reliability of communication, for example.

[0363] The aforementioned (3) may be, for example, the time from the moment the survival time requirement is not met until the communication channel is restored. The core network equipment, base station, and / or UE may use the value of (3) above to configure the communication channel between the base station and the UE. This will produce, for example, the same effect as described in (2) above.

[0364] The aforementioned (4) may, for example, be the average amount of time the application operates while meeting the survival time requirements. The core network equipment, base stations, and / or UEs may use the value of (4) above to configure the communication path between the base station and the UE. This can achieve, for example, the same effect as described in (2) above.

[0365] The aforementioned (5) may, for example, be the average amount of time the application is down without meeting the survival time requirements. The core network equipment, base stations, and / or UEs may use the value of (5) above to configure the communication path between the base station and the UE. This will, for example, have the same effect as (2) above.

[0366] The aforementioned (6) may be a parameter given as MTBF / (MTBF+MTTR) using the aforementioned (2) and (3). The core network equipment, base stations, and / or UEs may use the value of the aforementioned (6) to configure the communication path between the base station and the UE. This will produce the same effect as, for example, the aforementioned (2).

[0367] The aforementioned (7) may be a parameter given as MUT / (MUT+MDT) using the aforementioned (4) and (5). The core network equipment, base station, and / or UE may use the value of the aforementioned (7) to configure the communication path between the base station and the UE. This will produce the same effect as, for example, the aforementioned (2).

[0368] As the information in (8) above, for example, the packet delay budget disclosed in section 5.7.3.4 of Non-Patent Document 27 (TS23.501) may be used. The information in (8) above may be used when communication occurs periodically in the communication channel, or it may be used for non-periodic communication. The core network equipment, base stations, and / or UEs may use the value in (8) above to assign QoS to the data to be transmitted and received, or to schedule it. This makes it possible to prevent adverse effects on applications due to data latency exceeding the communication channel, for example.

[0369] The aforementioned (9) may be used, for example, when communication occurs periodically in a communication channel. The aforementioned (9) may be, for example, a value derived using the survival time value and the allowable latency, for example, the value obtained by dividing the survival time value by the allowable latency. Core network equipment, base stations, and / or UEs may use the aforementioned value of (9) to assign QoS to the data to be transmitted and received, or to perform scheduling. This can be used to obtain, for example, the same effect as the aforementioned (8).

[0370] The aforementioned (10) may be used, for example, when communication occurs periodically. The aforementioned (10) may be a value obtained in the same way as the aforementioned (9). By using the aforementioned (10), it becomes possible to prevent, for example, in a communication system, from falsely detecting scattered latency overloads as survival time overloads.

[0371] The aforementioned (11) may be used, for example, when data is not discarded after latency is exceeded. This makes it possible to prevent applications from being interrupted due to latency exceeding, for example, in communication systems where latency exceeding is not fatal.

[0372] The aforementioned (12) may be used, for example, when data is not discarded after latency is exceeded. By using the aforementioned (12), it becomes possible to prevent, for example, in a communication system, from falsely detecting scattered communication failures as exceeding the survival time.

[0373] The aforementioned (13) may be used, for example, when periodic communication occurs in a communication channel. The core network equipment, base station, and / or UE may use the value of (13) above to assign or schedule QoS for the data to be transmitted and received. This can achieve, for example, the same effect as in (8) above.

[0374] The aforementioned (14) may be used, for example, when communication occurs periodically in a communication channel. The aforementioned (14) may be determined, for example, using the survival time value, the communication period, and the size of the data transmitted and received in one period. The aforementioned (14) may also be the amount of data lingering in the RLC entity of the receiving device. This allows, for example, the receiving status of the receiving device to be quickly reflected in QoS control. As another example, the value of the aforementioned (14) may also be the amount of data lingering in the RLC entity of the transmitting device. This allows, for example, only data for which delivery confirmation has been obtained to be reflected in QoS control, and as a result, QoS control that is closer to the control status of the higher layer becomes possible.

[0375] The aforementioned (15) may be determined using, for example, the survival time value, the communication cycle, and the size of the data transmitted and received in one cycle. The aforementioned (15) may be the amount of data lingering in the PDCP entity of the receiving device, or it may be the amount of data lingering in the PDCP entity of the transmitting device, similar to the aforementioned (14). By using the amount of data lingering in the PDCP layer, for example, QoS control that is closer to the control status of the higher layer becomes possible.

[0376] Regarding (16) mentioned above, for example, survival time may be used as the product of the number of consecutive communication failures allowed and the communication cycle.

[0377] The aforementioned (1) to (16) may be used in combination with existing QoS parameters, such as those disclosed in Section 5.7.2 of Non-Patent Document 27 (TS23.501). This allows for flexible QoS control, for example.

[0378] Information regarding the survival time (e.g., the survival time value) may be notified by the AF. Such notification may, for example, require the 5G system to meet the survival time. Such notification may include information regarding communications that should meet the survival time. Information regarding communications that should meet the survival time may include, for example, information regarding the sending and receiving hosts (e.g., source IP address, destination IP address, source port number, and / or destination port number), and information regarding the transmitted data (e.g., information indicating whether it is TCP or UDP).

[0379] The AF may notify the core NW device of the information. The core NW device may be, for example, a PCF, a UDM, an SMF, an AMF, a UPF, or an NWDAF (Network Data Analytics Function; see Non-Patent Literature 31 (TS23.288)). The core NW device may use the information to perform QoS control in the communication system. For example, the core NW device may use the information to convert to (2) to (16) disclosed as examples of QoS parameters related to survival time, convert to existing QoS parameters, or convert to both of the above. As an example of the above conversion, the survival time value and the allowable latency may be used to derive the number of consecutive allowable latency exceedances by, for example, dividing the survival time value by the allowable latency value.

[0380] For example, the NWDAF may use the information from the AF to convert it into QoS parameters used in the communication system. The NWDAF may also use information acquired by the NWDAF (for example, input data disclosed in section 6.4.2 of Non-Patent Document 31 (TS23.288)) to convert it into QoS parameters. Information regarding shielding frequency disclosed in Modification 3 of Embodiment 3 may also be used. This makes it possible to perform QoS control that reflects the status of the communication system, and to reduce the amount of signaling in the derivation of the QoS parameters.

[0381] As another example, the AF may notify the core NW device of (1) to (16) disclosed as examples of QoS parameters related to survival time. The core NW device may be a PCF, UDM, SMF, AMF, UPF, or NWDAF (Network Data Analytics Function; see Non-Patent Literature 31 (TS23.288)), as described above. The core NW device may use this information to perform QoS control in the communication system. This makes it possible to reduce the processing load of QoS control in the core NW device, for example.

[0382] Information regarding survival time may be changed (e.g., updated, modified). The network-side device may notify the UE of changes to QoS parameters related to survival time. The AF may notify the core network device of such changes. The aforementioned notification may include (1) to (16) disclosed as examples of QoS parameters related to survival time. As another example, the aforementioned notification may include information regarding the reason for the change. The reason for the change may be, for example, a change in the environment in the application (e.g., a change in the time of day, season, etc., when the application is used), or it may be for other reasons.

[0383] The core network device may request the AF to change information regarding survival time. This request may include information regarding the reason for the change. This reason may include, for example, that there are too many requests for survival time from the AF, or that the AF is in a situation where it may not be able to meet the requests for survival time from the AF. The AF may use this request to change the QoS parameters related to survival time. This allows for, for example, more flexible operation of the communication system.

[0384] As another example, a base station may request the AF to change the information regarding survival time. The base station may make this request to the AF via the core network equipment. As yet another example, the UE may make this request. The UE may make this request via the base station or the core network equipment. The AF may use this request to change the information regarding survival time. This makes it possible, for example, to prevent application outages caused by the communication system no longer being able to meet survival time requirements.

[0385] Multiple pieces of information regarding survival time may be set for a single UE. For example, multiple applications may set information regarding survival time for a single UE. These multiple pieces of information may include, for example, multiple combinations of (1) to (16) and / or existing QoS parameters disclosed as examples of QoS parameters regarding survival time. The UE may use this information to communicate with the base station. This allows for flexible QoS control for different applications, for example.

[0386] Multiple such settings for a single UE may be applied to the core network equipment or to the base station. The core network equipment and / or base station may use these settings to perform QoS control and scheduling for the UE. This enables efficient scheduling, for example, in a communication system.

[0387] An application may configure multiple pieces of information related to survival time. For example, different information may be configured for the application's control purposes and for actual data. This configuration from the application may be made to the core network device or to the UE. This can, for example, improve the efficiency of QoS control in the application.

[0388] The information relating to survival time may include information regarding the validity period. For example, if survival time varies over time, a validity period may be set. This allows for flexible QoS control, for example, in a communication system.

[0389] A default value may be set for the information regarding survival time. The default value may be defined by a standard, determined by the core network equipment, determined by the AF, or determined by the base station. Each device in the communication system may use the default value to communicate if the information regarding survival time is not set. The default value may also be used when the aforementioned validity period expires. This can, for example, prevent malfunctions in the communication system.

[0390] QoS control using survival time may be performed at the data center (DC). Alternatively, QoS control using survival time may be performed at the base station on the mobile cluster (MCG) side within the DC. This allows for the avoidance of complexity in QoS control at the DC, for example. Another example is that the Secondary Cell Group (SCG) may perform QoS control. This allows for a reduction in the processing load at the MCG, for example. Another example is that both the MCG and SCG may perform QoS control. This allows for improved flexibility in QoS control.

[0391] As another example, QoS control may be performed within the cell group through which the QoS flow subject to QoS control passes. For example, if the QoS flow passes through an MCG bearer, the MCG may perform QoS control. If the QoS flow passes through a split bearer, the MCG and SCG may each perform QoS control. This allows for, for example, improved flexibility in QoS control. As yet another example, if the QoS flow passes through a split bearer, the MCG may perform QoS control. This allows for, for example, avoidance of complexity in QoS control.

[0392] As another example, a cell group performing SDAP processing may also perform QoS control. This cell group may be an MCG or an SCG. This allows the same cell group to perform both QoS flow mapping and QoS control, resulting in a reduction in the processing load for both QoS flow mapping and QoS control.

[0393] As another example, the cell group performing the PDCP processing may also perform QoS control. This QoS control may be applied, for example, when performing the processing of Modification 2 of Embodiment 3. This makes it possible to reduce the processing load of the communication system in the processing of Modification 2 of Embodiment 3, for example.

[0394] As another example, the cell group performing RLC processing may also perform QoS control. This would enable flexible QoS control that takes RLC ARQ into consideration, for example.

[0395] As another example, the cell group performing MAC processing may also perform QoS control. This QoS control may be applied, for example, when performing the processing of Modification 1 of Embodiment 3. This makes it possible to reduce the processing load of the communication system in the processing of Modification 1 of Embodiment 3, for example.

[0396] The MCG may notify the SCG of information regarding survival time. This information may be, for example, (1) to (16) disclosed above as examples of QoS parameters related to survival time. This makes it possible to prevent discrepancies in QoS control of survival time between the MCG and the SCG, and as a result, improve the stability of operation in the communication system.

[0397] Information regarding survival time may be acquired (or monitored). The information monitored may be, for example, (1) to (16) disclosed as examples of QoS parameters related to survival time. For example, with respect to (1) above, a survival time timer may be provided.

[0398] The aforementioned monitoring may be performed by the UE. The layer performing the aforementioned monitoring in the UE may be RRC, SDAP, PDCP, RLC, or MAC. As another example, the V2X layer in the sidelink (see Non-Patent Document 28 (TS23.287)) may perform the aforementioned monitoring. In the layer performing the aforementioned monitoring, for example, a survival time timer may be provided. For example, the timer may be activated when a HARQ NACK or a DCI for retransmission is received. This allows the UE to quickly reflect transmission failures in the HARQ layer in the survival time timer.

[0399] The UE may notify the base station of the information it has monitored as described above. RRC signaling may be used for this notification. This allows the UE to send more information to the base station, for example. As another example, MAC signaling may be used for this notification. This allows the UE to notify the base station more quickly, for example. As yet another example, L1 / L2 signaling may be used for this notification. This allows the UE to notify the base station even more quickly, for example. The base station may use this information to control the communication system. For example, the base station may change the coding rate in scheduling for the UE based on the number of consecutive communication failures exceeding a predetermined value. This allows, for example, to prevent the expiration of the survival time.

[0400] As another example, the UE may notify the AMF of the information. NAS signaling may be used for this notification. The AMF may use the information to control the communication system.

[0401] Another example of the aforementioned monitoring is that it may be performed by a base station. For example, it may be performed by a CU or a DU. The layer at which the aforementioned monitoring is performed at the base station may be RRC, SDAP, PDCP, RLC, or MAC. At the layer where the aforementioned monitoring is performed, for example, a survival time timer may be provided. For example, the timer may be activated when a HARQ NACK or a DCI for retransmission is received. This allows the base station to quickly reflect transmission failures at the HARQ layer in the survival time timer.

[0402] The base station may notify the UE of the information it has monitored as described above. Alternatively, the base station may notify the AMF of the same information. The AMF may use the information to control the communication system.

[0403] As another example of the aforementioned monitoring, the monitoring may be performed by a core network device. The aforementioned core network device may be a UPF, an AMF, or an SMF. For example, a UPF may perform the monitoring on U-plane data, an AMF may perform the monitoring on C-plane data, and an AMF may perform the monitoring on small data.

[0404] This third embodiment enables QoS control using survival time for both the network device and the UE, resulting in communication that meets the requirements of the application layer.

[0405] Modification 1 of Embodiment 3. QoS control using survival time may be used in the MAC. The MAC layer of the UE and / or base station may have a survival time timer. In the communication system, for example, data transmissions with a short time remaining until the survival time timer expires may be scheduled preferentially.

[0406] A survival time timer may be provided for each logical channel. This would, for example, improve the flexibility of the communication system.

[0407] In MAC scheduling, the parameter indicating priority (see Non-Patent Document 17 (3GPPTS38.321 V15.8.0)) may be dynamically variable. For example, a value obtained by subtracting a predetermined value (hereinafter sometimes referred to as the priority offset) from the priority value in Non-Patent Document 17 using the time remaining until the survival timer expires may be used in scheduling. The parameter indicating priority may be a parameter in which a lower value indicates a higher priority.

[0408] The reduced priority value may be kept from falling below a predetermined threshold. If the reduced priority value would fall below a predetermined threshold, the UE may set the reduced priority value to the same value as the predetermined threshold. The predetermined threshold may be defined in the standard, or it may be determined by the base station and notified to the UE. This prevents, for example, the reduced priority value from falling outside the range defined in the standard, thereby preventing malfunctions in LCP. In addition, as another example, it prevents the priority from being set excessively high in the priority offset.

[0409] The priority offset may be a uniform value within the survival time tolerance. This can, for example, avoid the design complexity in LCP.

[0410] As another example, the priority offset may be made variable within the survival time tolerance. For example, the priority offset may be increased when there is little time remaining until the survival time timer expires. This allows, for example, HARQ retransmissions to be sent preferentially even when they occur, and as a result, the retransmission can be sent before the survival time timer expires.

[0411] Priority offsets may be assigned to each time unit that constitutes a scheduling unit. For example, within the time range until the survival time timer expires, priority offsets may be set to have higher values ​​for later time intervals. This allows for more flexible allocation of logical channels in LCP, in addition to the effects described above. The time unit that constitutes a scheduling unit may be a subframe, a slot, a minislot, or a symbol.

[0412] Figure 18 illustrates the assignment of priority offsets in a logical channel with a survival time requirement. Figure 18 shows an example where, after the survival time timer is activated, the priority offset is set to increase as the remaining time of the timer decreases.

[0413] Figure 18 shows an example where the time it takes for the priority offset value to remain constant differs for each offset value. In contrast, the time it takes for the priority offset value to remain constant may be considered constant regardless of the offset value. This allows for, for example, avoiding design complexity in the LCP processing of the UE.

[0414] Priority offsets may be predetermined by the standard. For example, a uniform offset amount may be defined. Alternatively, an offset amount may be defined for each scheduling timing. Alternatively, the offset amount may be defined in correspondence with the range of remaining time until the survival time timer expires. As an example of the correspondence between the remaining time range and the offset amount, the time range from the start to the end of the survival time timer may be divided, and an offset amount may be defined for each divided range. For example, an offset amount may be defined for the range from the start of the survival time timer to the halfway point remaining until the end of the timer, and an offset amount may be defined for the range from the halfway point remaining until the end of the timer.

[0415] The logical channels to which the priority offset applies may be predetermined by the standard. For example, the priority offset may be applied to logical channels to which survival time requirements are set. This would allow, for example, the priority of such logical channels to be higher than other logical channels, thereby satisfying the survival time requirements.

[0416] As another example, the base station may determine the priority offset and notify the UE. For example, RRC signaling may be used for this notification. The notification may include information about the logical channel. This information may include information about the offset amount. The UE may apply the offset included in the notification to the logical channel included in the notification. The information about the offset amount may be similar to the offset amount predetermined by the standard. This allows the base station to notify the UE of more information, for example, thereby improving the flexibility in setting the priority offset.

[0417] Another example of such notification may be MAC signaling. The notification may include information about logical channels and information about offsets. The offset information may be similar to the offset amounts predetermined by the standard. The UE may apply the offsets included in the notification to the logical channels included in the notification. This allows the UE to apply the offsets quickly, for example.

[0418] Another example of such notification may be the use of L1 / L2 signaling. The notification may include information about the logical channel, or information about the offset. The notification may be included in a DCI containing a scheduling grant, in a different DCI, or transmitted via different L1 / L2 signaling. The offset information may be similar to an offset amount predetermined by the standard, or it may be the offset amount applied in the aforementioned grant. This allows, for example, the UE to apply the offset more quickly.

[0419] Multiple pieces of information regarding the offset amount may be provided. These multiple pieces of information may be defined by a standard, determined and notified to the UE by the base station, or determined and notified to the UE via the base station by the higher-level network equipment. The base station may notify the UE of the identifier of the information to be used from among the multiple pieces of information. RRC signaling, MAC signaling, or L1 / L2 signaling may be used to notify the identifier. The notification may include information about the logical channel to which the offset is applied. The UE may use the identifier to derive the information to be used. The base station may determine the information to be used using settings from the higher-level network equipment, for example, QoS parameters. Alternatively, the base station may determine the information to be used using information about network slicing. This can, for example, reduce the amount of signaling from the base station to the UE.

[0420] The following (1) to (6) are disclosed as examples of information regarding the priority offset amount that a base station notifies the UE of.

[0421] (1) Survival time value.

[0422] (2) Information about the logical channel to which the priority offset is applied.

[0423] (3) The number of priority offset patterns to assign.

[0424] (4) The value of the priority offset.

[0425] (5) The remaining time on the survival time timer to which the priority offset is applied.

[0426] (6) A combination of the above (1) to (5).

[0427] The information in (1) above may be the value of the survival time timer. The information in (1) above may also include, for example, the number of consecutive transmission failures allowed and the transmission cycle. For example, the information in (1) above may be the initial value of the survival time timer. This makes it possible to avoid complexity in setting the priority offset in the UE, for example.

[0428] The information in (2) above may be, for example, a Logical Channel ID (LCID). This allows, for example, the MAC layer of the UE to quickly determine which logical channel to assign a priority offset to.

[0429] The information in (3) above may also be the number of priority offset levels given in the logical channel. The number of levels may or may not include the case where there is no priority offset. For example, if a certain priority offset is assigned from when the remaining time of the survival time timer falls below half until the timer expires, the value in (3) above may be 1. This allows, for example, the MAC layer of the UE to quickly determine the number of priority offset levels. As a result, processing speed in the UE can be improved.

[0430] The information in (4) above may be the value of the priority offset given to the logical channel. As another example, the information in (4) above may be the increment of the priority offset value. This allows the UE to appropriately assign a priority offset to the logical channel, for example. As a result, the stability of the communication system can be improved.

[0431] The information in (5) above may be, for example, the value of the timer at which the assignment of the offset in (4) above begins. This allows the UE to appropriately assign a priority offset to the logical channel, for example. As a result, the stability of the communication system can be improved.

[0432] The information described in (4) and (5) above may be provided in multiple quantities, for example, the same number as the value in (3) above. This allows the UE to appropriately assign a priority offset to the logical channel, for example. As a result, the stability of the communication system can be improved.

[0433] The UE may use the information notified by the base station to assign an offset to the priority value. This offset may be assigned per logical channel or per HARQ process ID.

[0434] The UE may start the survival time timer upon receiving a HARQ NACK, or upon receiving scheduling information for HARQ retransmission. The base station may start the survival time timer when sending a HARQ NACK to the UE, or when sending scheduling information for HARQ retransmission. This prevents discrepancies in survival time timer values ​​between the UE and the base station, thereby preventing malfunctions in the communication system.

[0435] The method disclosed in this modified example 1 may be used after the survival time timer has expired. For example, a predetermined priority offset may be given after the survival time timer has expired. Alternatively, for example, a predetermined priority offset may be given in the Application Recovery Time described in Non-Patent Document 23 (TR22.832). The setting of the priority offset after the survival time timer has expired may be done in the same way as the setting of the priority offset before the timer has expired. The UE may use this setting to assign the priority offset after the survival time timer has expired. This makes it possible to quickly recover from the application outage caused by the expiration of the survival time timer, for example.

[0436] This modified version 1 allows the UE to prioritize data transmission when there is little time remaining until the survival time timer expires. As a result, it becomes possible to prevent the survival time timer from expiring.

[0437] Modification 2 of Embodiment 3. A survival time may be used in controlling packet replication. For example, packet replication may be performed automatically when the survival time timer starts. For example, a UE may automatically initiate packet replication when it receives scheduling information for HARQ retransmission. This scheduling information may include scheduling information used for transmitting the packets to be replicated.

[0438] As described above, the following problems arise. It has been discussed that the number of copies in packet duplication should be limited to a maximum of four (see Non-Patent Document 24 (3GPP RP-192590)). In this case, since the number of copies in automatic packet duplication is not disclosed, a discrepancy in operation occurs between the UE and the base station. For example, even though the base station expects four copies, the UE may duplicate the packet to two and send it. In that case, the base station's use of receiving resources becomes inefficient.

[0439] This modified example 2 discloses a method for resolving the aforementioned problems.

[0440] The number of packet duplicates is controlled using survival time. The UE implicitly changes the number of packet duplicates using survival time. For example, the UE may make the number of packet duplicates variable using the time remaining until the survival timer expires. The base station implicitly controls the number of packet duplicates using the survival time timer. For example, the base station may schedule the transmission resources used by the UE using the time remaining until the survival timer expires. The number of packet duplicates may increase as the survival time timer expires, for example.

[0441] Implicit packet replication may involve implicit control over the activation / deactivation of the legs used in packet replication.

[0442] A CA may be used for implicit packet replication. The base station may notify the UE of information about the cell used for implicit packet replication. The UE may use this information to send and receive data to and from the base station using that cell in implicit packet replication. This allows for the benefit of frequency diversity in implicit packet replication, for example. As a result, reliability in implicit packet replication can be improved.

[0443] A DC may be used for implicit packet replication. The base station may notify the UE of information about the cells used for implicit packet replication. This notification from the base station to the UE may include information about MCG cells or SCG cells. The UE may notify a cell group added in the DC of information indicating that implicit packet replication should be initiated. This cell group may be an SCG or an MCG. The cell group may use this notification from the UE to begin receiving or transmitting replicated packets. This allows for the benefits of frequency diversity and spatial diversity in implicit packet replication, resulting in improved reliability.

[0444] A CA and a DC may be used in combination for implicit packet replication. In packet replication using a CA and DC combination, the UE may notify cell groups added in the DC of information indicating that implicit packet replication should be initiated.

[0445] Figure 19 illustrates the implicit control of the number of packet copies in a logical channel with a survival time requirement. Figure 19 shows an example where, after the survival time timer is activated, the number of packet copies is set to increase as the remaining time on the timer decreases.

[0446] Figure 19 shows an example where the time it takes for the number of packet copies to become constant differs for each copy. In contrast, the time it takes for the number of packet copies to become constant may be considered constant regardless of the number of copies. This would, for example, allow for the avoidance of complexity in the design of packet replication processing by the UE.

[0447] The number of packet copies may be predetermined by the standard. For example, a uniform number of copies may be set. Alternatively, the number of packet copies may be set for each scheduling timing. Alternatively, the number of packet copies may be set in correspondence with the range of remaining time until the survival time timer expires. As an example of the correspondence between the range of remaining time and the number of packet copies, the time range from the start to the end of the survival time timer may be divided, and the number of packet copies may be set for each divided range. For example, the number of packet copies may be set for the range from the start of the survival time timer to the halfway point remaining until the end of the timer, and the number of packet copies may be set for the range from the halfway point remaining until the end of the timer.

[0448] The logical channels to which implicit control of packet replication is applied may be predetermined by the standard. For example, implicit control of packet replication may be applied to logical channels to which survival time requirements are set. This would allow packet replication to be automatically applied to such logical channels, thereby improving the reliability of those channels.

[0449] As another example, the base station may determine the packet replication count and notify the UE. For example, RRC signaling may be used for this notification. The notification may include information about logical channels. This information may include information about the packet replication count, or information about the remaining time on the survival time timer. The UE may apply the packet replication count included in the notification to the logical channels included in the notification. This information about the packet replication count may be the same as the packet replication count predetermined by the standard. This allows the base station to notify the UE of more information, for example, thereby improving the flexibility in implicit control of the packet replication count.

[0450] Another example of such notification may be MAC signaling. The notification may include information about a logical channel, information about the remaining time on a survival time timer, or information about the packet replication count. The packet replication count information may be similar to the packet replication count predetermined by the standard. The UE may apply the packet replication count included in the notification to the logical channel included in the notification. This allows the UE to quickly implement control over the packet replication count, for example.

[0451] Another example of such notification may involve L1 / L2 signaling. The notification may include information about the logical channel, information about the remaining time on the survival time timer, or information about the packet replication count. The notification may be included in a DCI containing a scheduling grant, in a different DCI, or transmitted via different L1 / L2 signaling. The packet replication count information may be similar to a packet replication count predetermined by the standard, or it may be the packet replication count applied in the aforementioned grant. This allows, for example, the UE to apply control over the packet replication count more quickly.

[0452] Multiple pieces of information regarding the packet replication count may be provided. These multiple pieces of information may be defined by a standard, determined and notified to the UE by the base station, or determined and notified to the UE via the base station by upstream network equipment. The base station may notify the UE of the identifier of the information to be used from among the multiple pieces of information. RRC signaling, MAC signaling, or L1 / L2 signaling may be used to notify the identifier. The notification may include information about the logical channel to which the packet replication count applies. The UE may use the identifier to derive the information to be used. The base station may determine the information to be used using settings from upstream network equipment, such as QoS parameters. Alternatively, the base station may determine the information to be used using information about network slicing. This can, for example, reduce the amount of signaling from the base station to the UE.

[0453] The following (1) to (8) are disclosed as examples of information regarding implicit control over the number of packet duplicates that a base station notifies the UE of.

[0454] (1) Survival time value.

[0455] (2) Information regarding wireless bearers to which implicit control of packet duplication is applied.

[0456] (3) The number of patterns for packet duplication.

[0457] (4) Number of packet copies.

[0458] (5) Whether DC is applicable.

[0459] (6) Information about the cells used for packet duplication.

[0460] (7) The remaining time on the survival time timer to which the packet duplication count applies.

[0461] (8) A combination of the above (1) to (7).

[0462] The information in (1) above may be the initial value of the survival time timer, or it may be information including, for example, the number of consecutive transmission failures allowed and the transmission cycle. This makes it possible to avoid complexity in packet duplication control in the UE, for example.

[0463] The information in (2) above may be, for example, the data radio bearer identifier (DRB-ID) before packet replication occurs. This allows, for example, the UE's PDCP layer to quickly identify the radio bearer on which implicit packet replication control is performed.

[0464] The information in (3) above may also be the number of packet replication patterns provided by the wireless bearer. The number of stages may or may not include the case where there is no packet replication. For example, if packet replication with a replication count of 4 occurs between the time the survival time timer is less than half remaining and the timer expires, the value in (3) above may be 1. This allows, for example, the UE's PDCP layer to quickly determine the number of packet replication stages. As a result, the processing speed at the UE can be improved.

[0465] The information in (4) above may also be the number of packet duplicates in the wireless bearer. As another example, the information in (4) above may be the increase in the number of packet duplicates. This allows the UE to appropriately control packet duplication in the wireless bearer, for example. As a result, the stability of the communication system can be improved.

[0466] Another example of the information described in (4) above may include information regarding the number of packet copies in the MCG and SCG, respectively. This information may be included, for example, when a DC is used in implicit packet replication. This allows for improved flexibility in implicit packet replication, for example.

[0467] The information in (5) above may, for example, indicate whether a DC is used for implicit packet replication at the timing in (7) above. The UE may use the information in (5) above to start or stop packet replication using the DC. This allows for, for example, improved flexibility in implicit packet replication.

[0468] The information in (6) above may be, for example, a cell identifier. The information in (6) above may include information about MCG cells used in implicit packet duplication, or information about SCG cells, or both. The UE may use the cells indicated in the information in (6) above to send and receive data with the base station. This makes it possible, for example, to reduce the amount of processing required for implicit packet duplication at the UE.

[0469] The information in (7) above may be, for example, the number of copies in (4) above and / or the value of the timer when DC is started in (5) above. This allows, for example, the UE to appropriately control packet duplication in the wireless bearer. As a result, the stability of the communication system can be improved.

[0470] The information described in (4) to (7) above may be set in multiple quantities, for example, the number of items may be equal to the value in (3) above. This allows the UE to appropriately control packet duplication of the wireless bearer, and as a result, improves the stability of the communication system.

[0471] A base station may change the implicit packet replication settings. The base station may change the implicit packet replication settings, for example, using measurement reports from the UE. The base station may notify the UE of the changed settings. Notification of the changed settings may include, for example, the information (1) to (8) disclosed as information regarding the implicit control of the number of packet replicas. This allows the base station to select an appropriate cell or cell group depending on the quality of communication with the UE, thereby improving the reliability of communication.

[0472] Similar to Modification 1 of Embodiment 3, the UE may start the survival time timer upon receiving a HARQ NACK, or upon receiving scheduling information for HARQ retransmission. The base station may start the survival time timer when transmitting a HARQ NACK to the UE, or when transmitting scheduling information for HARQ retransmission. This prevents discrepancies in survival time timer values ​​between the UE and the base station, and as a result, prevents malfunctions in the communication system.

[0473] The notification from the UE to the cell group may be made using L1 / L2 signaling, MAC signaling, or RRC signaling. The L1 / L2 signaling may be, for example, an SR. By using L1 / L2 signaling for the notification, the UE can, for example, provide rapid notification to the cell group.

[0474] The UE may notify the cell group of information indicating that implicit packet duplication will be stopped. This notification may be given, for example, when the survival time timer is stopped or initialized. The cell group may use this notification from the UE to stop receiving or not transmit duplicated packets. This allows for, for example, more efficient use of frequency and time resources within the cell group. The notification from the UE to the cell group indicating the cessation of implicit packet duplication may be given in the same way as the notification indicating the start of implicit packet duplication.

[0475] The UE may request the base station to change the settings regarding implicit packet replication. Such a request for change may be, for example, a request to increase the number of replications, a request to decrease the number of replications, a request to use DC for packet replication, a request to disable DC for packet replication, or a combination of several of the above. The base station may use the request to change the settings regarding implicit packet replication. The base station may notify the UE of the changed settings. The notification of the changed settings may include, for example, the information (1) to (8) disclosed as information regarding implicit control of the number of packet replications. This makes it possible, for example, to improve the reliability of implicit packet replication.

[0476] For example, RRC signaling may be used for the request. The RRC signaling may be, for example, a signaling requesting RRC reconfiguration. A new signaling may be established. This allows, for example, the UE to transmit more information to the base station. As another example, MAC signaling may be used for the request. This allows, for example, the UE to notify the base station of the request quickly. As yet another example, L1 / L2 signaling may be used for the request. This allows, for example, the UE to notify the base station of the request even more quickly.

[0477] The method disclosed in Modification 2 may be used after the expiration of the survival time timer. For example, implicit packet replication may be performed after the expiration of the survival time timer, or implicit packet replication may be performed during the application recovery time described in Non-Patent Document 23 (TR22.832). The setting for implicit packet replication after the expiration of the survival time timer may be performed in the same way as the setting for implicit packet replication before the expiration of the timer. The UE may use this setting to perform implicit packet replication after the expiration of the survival time timer. This makes it possible to quickly recover from an application outage caused by the expiration of the survival time timer, for example.

[0478] This modified version 2 allows the UE to improve the reliability of data transmission when there is little time remaining until the survival time timer expires. As a result, it becomes possible to prevent the survival time timer from expiring.

[0479] Modification 3 of Embodiment 3. Scheduling may be performed using survival time. For example, the scheduling for a UE may be automatically modified using the remaining time on the survival time timer. The UE may use information about the remaining time on the survival time timer to modify its own scheduling.

[0480] As an example of automatic scheduling changes using survival time, the following (1) to (7) are disclosed.

[0481] (1) Configured Grant.

[0482] (2) Information regarding the cells used for sending and receiving data.

[0483] (3) Information regarding the beams and / or antenna panels used by the UE.

[0484] (4) Information regarding the beams, antenna panels, and / or TRPs used by the base station.

[0485] (5) Information about the base station that will be the destination for the UE's transmission and reception.

[0486] (6) Information regarding the UE that will send and receive data.

[0487] (7) A combination of the above (1) to (6).

[0488] The pre-configured grants mentioned in (1) above may, for example, be allocated larger frequency resources when the remaining time on the survival time timer reaches a predetermined time. This allows the UE to transmit uplink data at a lower coding rate, thereby improving the reliability of communication.

[0489] In (2) above, for example, when the remaining time on the survival time timer reaches a predetermined time, a cell with a lower frequency may be used. This makes it possible to select a cell with a frequency that is less prone to interference when there is little time remaining until the survival time timer expires. As a result, the reliability of communication can be improved.

[0490] In (3) above, for example, when the remaining time on the survival time timer reaches a predetermined time, the beam and / or antenna panel to be used by the UE may be specified. The beam used by the UE may be, for example, the SRS beam, or it may be specified by information about the DMRS antenna port (for example, the DMRS antenna port number). (3) above may also be applied, for example, to uplink communications. This makes it possible to improve reliability in uplink communications, for example.

[0491] A base station may measure the uplink signal from the UE to each antenna panel and / or TRP of its base station. The uplink signal measured by the base station may be SRS or DMRS. The base station may also measure the frequency of shielding. The base station may retain the uplink measurement results. For example, the base station may retain information (e.g., a database) regarding the reliability of the uplink signal. This allows the base station to quickly select a highly reliable beam, antenna panel, and / or TRP.

[0492] In (4) above, for example, when the remaining time on the survival time timer reaches a predetermined time, the beam and / or antenna panel to be used by the base station may be specified. (4) above may also be applied, for example, to downlink communications. This makes it possible to improve reliability in downlink communications, for example.

[0493] The UE may measure the downlink signals from each antenna panel and / or TRP of the base station. The UE may, for example, measure the CSI-RS from the base station or measure the SS block. The UE may measure information regarding the frequency of shielding of the downlink signals. The UE may report information regarding the measurement results of the downlink signals to the base station. The UE may, for example, report measurement results regarding the frequency of shielding of the downlink signals to the base station. Information regarding the frequency of shielding may, for example, be the number of times the received strength of the downlink signal falls below a predetermined threshold within a predetermined time, or the time for which the received strength of the downlink signal falls below a predetermined threshold. The base station may use this information to determine the beam, antenna panel, and / or TRP to be used for downlink communication with the UE. This makes it possible to avoid beams that are prone to shielding in downlink communication between the base station and the UE. As a result, the reliability of downlink communication can be improved.

[0494] With respect to (3) and / or (4) above, the base station may notify the NWDAF (Network Data Analytics Function; see Non-Patent Document 31 (TS23.288)) of the measurement results of the uplink and / or downlink signals. The measurement results may include, for example, information on the frequency of shielding. An interface may be provided between the base station and the NWDAF. The NWDAF may use the measurement results to generate and maintain information (e.g., a database) on the reliability of the uplink and / or downlink signals. The NWDAF may notify the base station of this reliability information. The base station may use this reliability information to determine the beam and / or antenna panel to be used by the UE, or to determine the beam and / or antenna panel to be used by its own base station. This can reduce the processing load on the base station with respect to (3) and (4) above, for example.

[0495] The UE may notify the NWDAF of the measurement results of the downlink signal. An interface may be provided between the UE and the NWDAF. The NWDAF may use this information from the UE to generate and maintain information regarding the reliability of the downlink signal. This can, for example, reduce the processing load on the base station.

[0496] As another example, the Operations, Administration and Maintenance (OAM) may notify the NWDAF of information regarding shielding frequency. The OAM may derive the shielding frequency using measurement results from the UE. The OAM may include the notification of shielding frequency information to the NWDAF in notifications regarding RSRP, notifications regarding RSRQ, or notifications regarding SINR. This can, for example, reduce the amount of signaling in the communication system.

[0497] As another example, the NWDAF may derive information regarding shielding frequency. The NWDAF may derive information regarding shielding frequency using, for example, information regarding RSRP, RSRQ, and / or SINR that has been notified to the NWDAF by the OAM (Operations, Administration and Maintenance). The NWDAF may notify the OAM, the base station, the AMF, the SMF, the UPF, the PCF, or the AF (Application Function) of this information regarding shielding frequency. For example, the base station may use this information regarding shielding frequency to determine the information described in (3) and / or (4) above. This can, for example, reduce the amount of signaling in the communication system and improve the reliability of communication between the base station and the UE.

[0498] The aforementioned (5) may be, for example, an identifier of the base station to which the UE transmits and receives data (e.g., gNB-ID), an identifier indicating whether it is a master base station or a secondary base station, or a serial number assigned to the base station to which the UE connects. Each of the aforementioned identifiers may be applied, for example, when the UE is using a DC configuration, or when multi-connectivity is used (e.g., when the UE is connected to three or more base stations). This can, for example, provide the effect of spatial diversity, which in turn can improve reliability.

[0499] The aforementioned (6) may be, for example, an identifier for the UE (e.g., UE-ID), or an identifier assigned to each UE within the application device. The aforementioned (6) may also apply, for example, when multiple UEs are installed in a single application device. This will produce, for example, the same effect as the aforementioned (5).

[0500] The base station may notify the UE of scheduling information. The UE may use this information to send and receive data with the base station.

[0501] Examples of scheduling information that a base station notifies a UE of include the following (1) to (5).

[0502] (1) Survival time value.

[0503] (2) The number of automatic scheduling patterns.

[0504] (3) Information regarding automatic scheduling.

[0505] (4) The remaining time on the survival time timer to which automatic scheduling is applied.

[0506] (5) A combination of (1) to (4) above.

[0507] The information in (1) described above may be the same as the information in (1) disclosed as information regarding the priority offset amount in Modification 1 of Embodiment 3. This makes it possible to avoid complexity in setting up automatic scheduling in the UE, for example.

[0508] The information in (2) above may be the same as the information in (3) disclosed as information regarding the priority offset amount in Modification 1 of Embodiment 3. This allows the UE to quickly grasp the number of stages in automatic scheduling, and as a result, improve the processing speed in the UE.

[0509] The information in (3) above may be the information in (1) to (7) disclosed in this modified example 3 as an example of automatic scheduling change using survival time. This enables, for example, appropriate scheduling from the base station to the UE, and as a result, improves the stability of the communication system.

[0510] The information in (4) above may be the same as the information in (5) disclosed as information regarding the priority offset amount in the modified example 1 of Embodiment 3. This enables, for example, appropriate scheduling from the base station to the UE, and as a result, improves the stability of the communication system.

[0511] The information described in (3) and (4) above may be provided in multiple quantities, for example, the number of items may be equal to the value in (2) above. This makes it possible, for example, to schedule appropriate events from the base station to the UE, and as a result, improve the stability of the communication system.

[0512] This modified version 3 enables the base station to reliably schedule data transmission for the UE when there is little time remaining until the survival time timer expires. As a result, it becomes possible to prevent the survival time timer from expiring.

[0513] The embodiments and their variations described above are merely illustrative, and these embodiments and their variations can be freely combined. Furthermore, any component of each embodiment and its variations can be modified or omitted as appropriate.

[0514] For example, in the embodiments and their modifications described above, a subframe is an example of a time unit for communication in a fifth-generation base station communication system. It may also be a scheduling unit. In the embodiments and their modifications described above, the processing described as being performed in subframe units may also be performed in TTI units, slot units, sub-slot units, or mini-slot units.

[0515] For example, the methods disclosed in each of the embodiments and their modifications described above may be applied not only to V2X (Vehicle-to-everything) services but also to services that use SL communication. SL communication is used in a variety of services, such as proximity-based services, public safety, communication between wearable devices, and communication between machines in factories. The methods disclosed in each of the embodiments and their modifications described above may be applied to SL communication used in such a variety of services.

[0516] Although this disclosure has been described in detail, the above description is illustrative in all respects and the disclosure is not limited thereto. It is understood that countless variations not illustrated may be conceivable without falling outside the scope of this disclosure. [Explanation of Symbols]

[0517] 200, 210 Communication systems, 202 Communication terminal equipment, 203 Base station equipment.

Claims

1. A terminal device having multiple SIMs (Subscriber Identity Modules) and configured to connect to multiple networks using the multiple SIMs, The aforementioned plurality of networks include a first network including an AMF (Access and Mobility Management Function) and a second network, The terminal device is configured to receive information from the AMF related to avoiding paging collisions between the multiple networks. Terminal device.

2. The aforementioned information includes the modified identification information of the terminal device, The terminal device is configured to receive NAS (Non-Access Stream) signaling containing the modified identification information from the AMF. The terminal device according to claim 1.

3. The modified identification information is the 5G-GUTI (5G Globally Unique Temporary Identifier) ​​modified by the AMF. The terminal device according to claim 2.

4. Based on the modified 5G-GUI, the timing of paging by the first network is changed. The terminal device is configured to receive paging from the first network at the modified paging timing. The terminal device according to claim 3.

5. The terminal device is configured to transmit the NAS signaling to the AMF to notify it of the completion of the 5G-GUI update. The terminal device according to claim 3.

6. Priority is assigned to paging by the aforementioned AMF. The terminal device is configured to receive the paging to which the priority has been assigned. The terminal device according to claim 1.

7. When the terminal device switches from the first network to the second network, the terminal device is configured to transmit RRC (Radio Resource Control) signaling, which includes information regarding the switch, to the first network. The terminal device according to claim 1.

8. A communication system including a terminal device having multiple SIMs (Subscriber Identity Modules) and configured to connect to multiple networks using the multiple SIMs, The aforementioned plurality of networks include a first network including an AMF (Access and Mobility Management Function) and a second network, The terminal device is configured to receive information from the AMF related to avoiding paging collisions between the multiple networks. Communication system.

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