Terminal, method, base station and communication system

Abstract

A terminal according to one aspect of the present disclosure comprising: a receiver configured to monitor paging; and a processor configured to control the receiver to stop monitoring of the paging after a specific timing, when a condition for stopping monitoring of the paging is met. According to one aspect of the present disclosure, at least one of UE power saving and resource / service efficiency can be achieved appropriately.

Description

TERMINAL, METHOD, BASE STATION AND COMMUNICATION SYSTEMCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims priority to U.S. Provisional Application No. 63 / 717,992, filed on November 8, 2024, the contents of which are incorporated herein by reference in their entirety.

[0002] Apparatuses and methods consistent with the present disclosure relate generally to communications, more specifically, methods, systems, and devices for efficient power and resource savings.

[0003] Modern mobile communication services utilize both terrestrial and non-terrestrial networks (NTN). Third Generation Partnership Project (3GPP) radio interfaces incorporate NTN features (Non Patent Literature 1).

[0004] For NTNs, the 3GPP starts considering a Store & Forward (S&F) mode, allowing satellites to collect data from users when feeder links are unavailable and sending it to ground stations once feeder link connections are restored.

[0005] In NTN systems, particularly those using the S&F mode, techniques have been proposed for User Equipment (UE) power saving. For example, it is known that a UE can stop monitoring for paging when a satellite, acting as a base station, indicates that it does not have any buffered mobile terminated (MT) data intended for the UE.

[0006] 3GPP TS 38.300 V18.3.0, “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; NR and NG-RAN Overall Description; Stage 2 (Release 18)”

[0007] However, a problem with this technique arises from the significant propagation delay in the feeder link between the satellite and the ground network. A paging message sent from the core network just before the feeder link becomes unavailable may still be in transit. If the UE stops monitoring immediately, it risks missing this late-arriving paging message, which can lead to data loss, delayed data reception, and inefficient use of network resources for repeated paging attempts.

[0008] Therefore, one object of the present disclosure is to provide a terminal, a method, a base station and a communication system that can achieve a balance between UE power saving and resource / service efficiency. It is another object of the present disclosure to provide a solution that prevents the loss of MT data by mitigating the risk of a UE missing a paging message due to propagation delays, while still allowing the UE to save power by stopping paging monitoring.

[0009] A terminal according to one aspect of the present disclosure comprising: a receiver configured to monitor paging; and a processor configured to control the receiver to stop monitoring of the paging after a specific timing, when a condition for stopping monitoring of the paging is met.

[0010] According to one aspect of the present disclosure, at least one of UE power saving and resource / service efficiency can be achieved appropriately.

[0011] FIG. 1 is a schematic diagram illustrating a system for some embodiments of the present disclosure.

[0012] FIG. 2 is a schematic diagram illustrating an exemplary functional configuration of each device for some embodiments of the present disclosure.

[0013] FIG. 3 is a schematic diagram illustrating an exemplary hardware configuration of each device for some embodiments of the present disclosure.

[0014] FIG. 4 is a schematic diagram illustrating Non-Terrestrial Network (NTN) for LTE.

[0015] FIG. 5 is a schematic diagram illustrating an exemplary flow chart of a procedure for stopping monitoring Paging in one embodiment in the present disclosure.

[0016] The present disclosure may introduce a method and apparatus for efficient power and resource savings in a radio communication system.

[0017] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elements unless otherwise represented. The implementations set forth in the following description of exemplary embodiments do not represent all implementations consistent with the present disclosure. Instead, they are merely examples of systems, apparatuses, and methods consistent with aspects related to the present disclosure as recited in the appended claims.

[0018] In the present disclosure, "A / B," “A and / or B” and "at least one of A and B" may be used interchangeably. In the present disclosure, "A / B / C," “A and / or B and / or C” and "at least one of A, B and C" may be used interchangeably.

[0019] In the present disclosure, a word / phrase surrounded by "()" in a sentence may indicate an explanation (e.g. spelling explanation), paraphrase, concrete example or supplementary explanation of an immediately preceding word / phrase. In the present disclosure, regarding a phrase enclosed by "[]" in a sentence, the meaning of the entire sentence including the phrase may be interpreted with including the phrase, or may be interpreted without including the phrase (ignoring it). Note that ‘()’ and ‘[]’ may be used for other purposes / meanings.

[0020] <System> FIG. 1 is a schematic diagram illustrating a system for some embodiments of the present disclosure. The system 1 may be a system implementing a communication using Long Term Evolution (LTE), 5th generation mobile communication system New Radio (5G NR) and so on the specifications of which have been drafted by Third Generation Partnership Project (3GPP). The system 1 may include at least one of Evolved Packet System (EPS), 5G system (5GS), and so on. The system 1 may include one or more user equipment (UE) 10, one or more base stations (BS) 20, one or more core networks (CN) 30.

[0021] In the present disclosure, terms “system,” “radio system,” “radio communication system,” “radio interface,” and “network (NW)” are used as general terms which include one or both of terrestrial network systems and non-terrestrial network (NTN) systems such as satellite systems. In the present disclosure, these terms may be used interchangeably.

[0022] The UE 10 may be a terminal supporting at least one of communication schemes such as LTE, 5G NR, and so on. The UE 10 may be connected to at least one of plurality of BS 20. The UE 10 may take any form, including but not limited to, a vehicle, a component mounted in a vehicle, a road-side unit, a laptop computer, a wireless terminal including a mobile phone, a wireless handheld device, or wireless personal device.

[0023] In the present disclosure, a UE, a mobile station, a mobile node and a terminal may be used interchangeably.

[0024] The plurality of base stations 10 may be connected each other by a wired connection (for example, optical fiber) or a wireless connection (for example, an NR communication). The base station 10 may be connected to a core network 30 through another base station 10 or directly.

[0025] In the present disclosure, a BS may be referred to as the terms such as a NodeB, an eNodeB (eNB), a gNodeB (gNB), a radio access network (RAN), a carrier, a component carrier, a sector, a cell, a cell group, a super cell, a macro cell, a small cell, a femto cell, a pico cell, and so on. In the present disclosure, a network may mean an apparatus (for example, a BS) included in the network.

[0026] In the present disclosure, a term “node” is used as a general term which includes user equipment (UE), a relay node, a vehicle mounted module, a station, a network infrastructure node such as a base station (BS), a roadside unit, a repeater, a transponder, a wireless router, a controller, an access point, a transmission point (TP), a reception point (RP), a transmission / reception point (TRP), a panel, and sub-systems thereof. In the present disclosure, these entities (apparatuses, devices) may be used interchangeably.

[0027] The communication between UE 10 and BS 20 may be transferred via one or more apparatuses for NTN, e.g., a Geostationary Earth Orbit (GEO) satellite, a Medium-Earth Orbit (MEO), a Low Earth Orbit (LEO) satellite, a High Altitude Platform Station (HAPS), an NTN payload and an NTN gateway. In the present disclosure, the BS 20 may include a BS in a terrestrial network and / or a BS in NTN (or the BS on / within the above one or more apparatuses for NTN). In the present disclosure, the BS and the above one or more apparatuses for NTN may be used interchangeably.

[0028] The NTN (or the system 1) may provide a non-terrestrial NR access to the UE 10 by means of the NTN payload and the NTN Gateway. A wireless link between the NTN payload and the UE 10 may be called as a service link, and a wireless link between the NTN Gateway and the NTN payload may be called as a feeder link.

[0029] A satellite, such as GEO, MEO, LEO and HAPS, may be a space-borne vehicle orbiting the Earth embarking the NTN payload. The NTN payload may be a network node, embarked on board the satellite, providing connectivity functions, between the service link and the feeder link. The NTN Gateway may be an earth station (also referred to as a ground station) located at the surface of the earth, providing connectivity to the NTN payload using the feeder link.

[0030] The NTN payload may transparently forward the radio protocol received from the UE 10 (via the service link) to the NTN Gateway (via the feeder link) and vice-versa.

[0031] A satellite may directly communicate with another satellite via inter-satellite link (ISL). The ISL may work as a satellite backhaul.

[0032] The core network 30 may include at least one of Evolved Packet Core (EPC), 5G Core Network (5GCN), and so on.

[0033] In the system 1, an orthogonal frequency division multiplexing (OFDM)-based wireless access scheme may be used. For example, in at least one of the downlink (DL) communication and the uplink (UL) communication, Cyclic Prefix OFDM (CP-OFDM), Discrete Fourier Transform Spread OFDM (DFT-s-OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), and the like may be used.

[0034] <Functional / Hardware Configuration of Device> FIG. 2 is a schematic diagram illustrating an exemplary functional configuration of each device for some embodiments of the present disclosure. For example, the UE 10 may have a control unit 110, a communication unit 120, an input / output unit 130, and a storage unit 140.

[0035] The BS 20 may have similar functional configurations. For this reason, in this exemplary functional configuration, the sign of the functional block corresponding to each device is also shown with the largest digit of the sign indicating each device (e.g., the largest digit "2" of "20" for BS 20) replaced with "1". In the following, the functional blocks relating to the UE 10 will be explained, but it is understood that the same explanation applies to other devices as well.

[0036] In this example, the functional blocks of the characteristic parts of the system are mainly shown, and each device may also have other functional blocks necessary for other processes. The configuration may also not include some of the functional blocks.

[0037] Note that in the present disclosure, the words such as an apparatus, a circuit, a device, a section, a unit, and so on may be interchangeably interpreted.

[0038] The control unit 110 implements control of the UE 10 and provides various functions. For example, the control unit 110 may control communication with other devices via the communication unit 120. The control unit 110 may also obtain information necessary for processing based on information received via the communication unit 120. The control unit 110 may be referred to as a processing unit.

[0039] The communication unit 120 communicates (transmits / receives) with other devices via wired / wireless communication. The communication unit 120 may obtain information from the received signal and output it to the control unit 110, or it may convert information input from the control unit 110 into a signal and transmit it. The communication unit 120 may perform measurement on the received signal and output the measurement result to the control unit 110. The communication unit 120 may be referred to as a transmitter, receiver, or transmitter / receiver. The communication unit 120 may be referred to as a measurement unit.

[0040] The input / output unit 130 may include an input unit that accepts input from a person. The input unit may be connected to a predetermined device, storage medium, etc., and may accept data input. The input unit may output input results to, for example, the control unit 110.

[0041] The input / output unit 130 may also include an output unit that outputs data, content, etc. in a format that can be perceived by humans. The output unit may comprise a display unit that displays images, an audio output unit that outputs sound, and the like.

[0042] The storage unit 140 stores (holds) various information used by the management unit 10 for processing. The control unit 110 may instruct the storage unit 140 to read and write data.

[0043] The functional blocks (components) in FIG. 2 may be implemented in arbitrary combinations of at least one of hardware and software. Each functional block may be realized by one apparatus that is physically or logically coupled, or may be realized by directly or indirectly connecting two or more physically or logically separate apparatuses (for example, via wire, wireless, or the like) and using these apparatuses. The functional blocks may be implemented by combining softwares into the apparatus described above or the plurality of apparatuses described above.

[0044] FIG. 3 is a schematic diagram illustrating an exemplary hardware configuration of each device for some embodiments of the present disclosure. For example, the UE 10, the BS 20, and the other devices in the present disclosure may function as a computer that executes the processes of the radio communication method(s) in the present disclosure. Each device may have an antenna 910, a Radio Frequency (RF) circuit 920, a processor 930, a network interface 940, an input device / output device 950, a memory 960, and a storage 970.

[0045] For example, the above control unit X10 (e.g., X = 1, 2; same below) described above may be implemented by the processor 930. The communication unit X20 may be implemented by the antenna 910 / RF circuit 920 / network interface 940. The input / output unit X30 may be implemented by the input device / output device 950. The storage unit X40 may be implemented by the memory 960 / storage 970.

[0046] The hardware configuration of each device may be configured to include one or more of the elements shown in this exemplary hardware configuration, or may be configured without some of the elements. For example, the UE 10 may not have a network interface 940.

[0047] The antenna 910 converts signals into radio waves and radiates said radio waves into space. The antenna 910 also receives radio waves in space and converts said radio waves into signals. The antenna 910 may be mounted in plurality, may include a transmitting antenna and a receiving antenna, or may include a single antenna for transmitting and receiving. The antenna 910 may include a directional antenna or may include multiple antenna elements. The antenna 910 may include one or more antenna elements and may enable different input-output antenna configurations.

[0048] The RF circuit 920 performs analog processing of signals transmitted and received via antenna 910. The RF circuit 920 may include filters (e.g., high frequency filters, low pass filters), amplifiers, modulators, frequency synthesizers, analog-to-digital conversion circuit, digital-analog conversion circuit, Fast Fourier Transform (FFT) / Inverse Fast Fourier Transform (IFFT) processing circuit, etc.

[0049] The RF circuit 920 may perform amplification, filter processing, demodulation to a baseband signal, etc. on the received radio frequency band signal and output to processor 930 RF circuit 920 may perform modulation to a radio frequency band, filter processing, amplification and transmit the radio frequency band signals via the transmitter / receiver antenna 910. The RF circuit 920 may perform physical layer processing (e.g., processing of lower functions of the physical layer), and may perform beamforming processing such as analog beamforming and digital beamforming processing.

[0050] The processor 930 may control the entire device. The processor 930 may read programs (program code), software (software modules), data, and the like from the storage 970 to the memory 960 and perform various processes according to these. For example, the processor 930 may execute and control an operating system (OS) program that is loaded into the memory 960. The programs are used to allow computers to execute at least part of methods (operations) shown in embodiments of the present disclosure. For example, the control unit 110 (210) may be implemented by control programs that are stored in the memory 960 and that operate on the processor 930, and other functional blocks may be implemented likewise.

[0051] The processor 930 may be configured by a central processing unit (CPU), which may include interfaces to peripheral devices, control units, arithmetic units, registers, and the like. The processor 930 may also be a microprocessor, Digital Signal Processor (DSP), Application Specific Integrated Circuit (ASIC), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), Graphics Processing Unit (GPU), Neural Processing Unit (NPU), etc.

[0052] The processor 930 may perform digital processing of signals transmitted and received via the antenna 910 and the RF circuit 920. Said digital processing may include physical layer processing (e.g., processing of higher functions of the physical layer), processing of layers above the Medium Access Control (MAC) layer, modulation, demodulation, coding, decoding, scrambling, etc. The processor 930 also processes signals sent and received via network interface 940.

[0053] The processor 930 may include a plurality of processors or may be a single processor. The multiple processors may include a baseband processor that performs the digital processing described above and one or more processors that perform other processing (e.g., overall control).

[0054] The network interface 940 may be, for example, a network adapter, which may be wired to an external network to send and receive signals.

[0055] The RF circuit 920 / baseband processor / network interface 940 may be an integral part of the RF circuit 920 / baseband processor / network interface 940. The network interface 940 may be referred to as a network controller, network card, communication module, etc.

[0056] The input device / output device 950 may comprise an input device that accepts external input (e.g., keyboard, mouse, microphone, switches, buttons, sensors, etc.), an output device that performs external output (e.g., display, speaker, Light Emitting Diode (LED) lamp etc.), and a device (e.g., a touch panel) that integrates these devices. The sensors may include a locator (e.g., a receiver corresponding to Global Navigation Satellite System (GNSS)) to obtain position information.

[0057] The memory 960 is a computer-readable, non-transitory storage medium that stores a program to be executed by the processor 930, parameters related to said program, and various other information. The memory 960 is at least one of Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically EPROM (EEPROM), Random Access Memory (RAM), and flash memory. All or part of the memory 960 may be contained within processor 930. Memory 960 may be referred to as a register, cache, main memory (main storage), etc.

[0058] The storage 970 is a computer-readable, non-transitory storage medium that stores a variety of information. The storage 970 may include, for example, flexible disks, floppy (registered trademark) disks, magneto-optical disks (e.g., compact disc (Compact Disc ROM (CD-ROM), digital versatile disk, Blu-ray (registered trademark) disk), a removable disk, a hard disk drive (Hard Disc Drive (HDD)), a smart card, a flash memory device (e.g., Solid State Drive (SSD)), or at least one other. The storage 970 may be referred to as an auxiliary storage device.

[0059] The processor 930, memory 960, and other devices may be connected by a bus for communicating information. A single bus may be used within a device, or different buses may be used between devices.

[0060] The BS 20 may be separated into three elements: the Radio Unit (RU), the Distributed Unit (DU), and the Central Unit (CU). The RU implements RF processing and lower functions of the physical layer. The DU implements the upper functions of the physical layer, the functions of the MAC layer, and the functions of the Radio Link Control (RLC) layer. The CU realizes the functions of the Packet Data Convergence Protocol (PDCP) layer, the Service Data Adaptation Protocol (SDAP), and the Radio Resource Control (RRC) layer.

[0061] In this disclosure, BS 20 may include one device that realizes all the functions of RU, DU and CU, or may include multiple devices that each realize some of the functions of RU, DU and CU.

[0062] Other devices in the present disclosure may also be implemented by multiple devices that are physically located apart from each other. Conversely, a plurality of different devices in this disclosure may be implemented as a single device.

[0063] Some or all of the devices in this disclosure may also mean logical devices realized by virtual machines, containers, Docker, etc., or physical devices that operate such logical devices.

[0064] <Store & Forward (S&F) mode for Non-Terrestrial Network (NTN)> Non terrestrial networks (NTN) can be used instead of terrestrial networks, for example because NTN can reach areas on earth where deploying terrestrial network nodes may be costly or almost impossible. NTN started to be standardized for the 3GPP Release 17. 3GPP TS 36.304 defines NTN as the following, for the example of LTE: “Non-Terrestrial Network: An E-UTRAN consisting of eNBs, which provide non-terrestrial LTE access to UEs by means of an NTN payload embarked on a space-borne NTN vehicle and an NTN Gateway.”

[0065] A Non-Terrestrial Network (NTN) provides non-terrestrial access by means of an NTN payload and an NTN Gateway, depicting a service link between the NTN payload and a UE, and a feeder link between the NTN Gateway and the NTN payload.

[0066] In 3GPP Rel-17 and Rel-18, The NTN payload transparently forwards the radio protocol received from the UE (via the service link) to the NTN Gateway (via the feeder link) and vice-versa. An overall illustration of Rel-17 / Rel-18 Non-Terrestrial Network (NTN) for LTE is depicted in FIG. 4.

[0067] At the 3GPP RAN#102 meeting, a new WID for Release 19 further enhancements on Non-Terrestrial Networks (NTN) for Internet of Things (IoT) was approved, and in RAN#103 meeting, the Work Item Description (WID) was further revised and approved in RP-240776; “Revised WID on Non-Terrestrial Networks (NTN) for Internet of Things (IoT) Phase 3.” The main objectives related to support of Store&Forward (S&F) satellite operation are as follows: The aim of this WI is enhancement of IoT-NTN with the following objectives: Support of Store&Forward (S&F) satellite operation with full eNB as regenerative payload, therefore: Define the necessary enhancements into E-UTRAN (network & UE) to support S&F operation for delay-tolerant services [RAN3, RAN2] At least specify necessary enhancements e.g. related to S1 protocol, especially to address the feeder link switch over as needed [RAN3] Note: Strive to minimise UE impact. Note: Coordination with SA2 (Rel-19 SA2 led Sat-Arch ph3 SI) is needed on the detail requirements (e.g. traffic type, or QoS parameters for S&F), network architecture (e.g. whether consider (partial) core network on satellite) etc.; further coordination with CT1 might be required

[0068] S&F operation allows satellites to collect data from users when feeder links are unavailable, and to send it to ground stations once feeder link connections are restored.

[0069] S&F operation allows for delay-tolerant, non-real-time IoT NTN services to be offered in areas visited by the satellites but with no need to have NTN gateway infrastructure (e.g., mid-sea, remote areas). The intention may be to facilitate cost-effective deployment of IoT NTN services and enable an immediate operational service with sparse Low Earth Orbit (LEO) constellations and reduced ground segment infrastructure.

[0070] S&F makes use of a regenerative payload architecture. In the scenario of S&F, the Core Network, Access and Mobility Management Function (AMF) or Mobility Management Entity (MME) on ground, sends Mobile Terminated (MT) data to the satellite when the feeder link is available. The satellite receives the MT data and stores it. When the service link is available, the satellite pages the UE, or the UE initiates RRC connection, and then the satellite sends MT data to the UE.

[0071] <Paging> 3GPP TS 36.304 describes paging-related operations for LTE as follows: - The UE may use Discontinuous Reception (DRX) in idle mode in order to reduce power consumption. One Paging Occasion (PO) is a subframe where there may be P-RNTI transmitted on PDCCH or MPDCCH or, for NB-IoT on NPDCCH addressing the paging message. In P-RNTI transmitted on MPDCCH case, PO refers to the starting subframe of MPDCCH repetitions. In case of P-RNTI transmitted on NPDCCH, PO refers to the starting subframe of NPDCCH repetitions unless subframe determined by PO is not a valid NB-IoT downlink subframe then the first valid NB-IoT downlink subframe after PO is the starting subframe of the NPDCCH repetitions. The paging message is same for both RAN initiated paging and CN initiated paging. - The UE initiates RRC Connection Resume procedure upon receiving RAN paging. If the UE receives a CN initiated paging in RRC_INACTIVE state, the UE moves to RRC_IDLE and informs NAS. - One Paging Frame (PF) is one Radio Frame, which may contain one or multiple Paging Occasion(s). When DRX is used the UE needs only to monitor one PO per DRX cycle.

[0072] Moreover, 3GPP TS 38.304 describes paging-related operations for 5G / NR as follows: - The UE may use Discontinuous Reception (DRX) in RRC_IDLE and RRC_INACTIVE state in order to reduce power consumption. The UE monitors one paging occasion (PO) per DRX cycle. A PO is a set of PDCCH monitoring occasions and can consist of multiple time slots (e.g. subframe or OFDM symbol) where paging DCI can be sent (TS 38.213 [4]). One Paging Frame (PF) is one Radio Frame and may contain one or multiple PO(s) or starting point of a PO. A L2 U2N Relay UE monitors the paging occasions of its PC5-RRC connected L2 U2N Remote UEs. In this case, the DRX cycle and UE ID mentioned in this clause refer to those of the L2 U2N Remote UE. - In multi-beam operations, the UE assumes that the same paging message and the same Short Message are repeated in all transmitted beams and thus the selection of the beam(s) for the reception of the paging message and Short Message is up to UE implementation. The paging message is same for both RAN initiated paging and CN initiated paging. - The UE initiates RRC Connection Resume procedure upon receiving RAN initiated paging. If the UE receives a CN initiated paging in RRC_INACTIVE state, the UE moves to RRC_IDLE and informs NAS. However, if a L2 U2N Relay UE in RRC_INACTIVE state receives a CN initiated paging for a L2 U2N Remote UE, the L2 U2N Relay UE does not move to RRC_IDLE state. - The UE may be configured by upper layers and / or RRC with an extended DRX (eDRX) cycle TeDRX, CN and / or TeDRX, RAN. - For CN paging, the UE operates in eDRX in RRC_IDLE or RRC_INACTIVE states if the UE is configured for eDRX by upper layers and eDRX-AllowedIdle is signalled in SIB1; otherwise, the UE does not operate in eDRX. - For RAN paging, the UE in RRC_INACTIVE state: - if the UE is configured for eDRX by ran-ExtendedPagingCycleConfig-r18 and eDRX-AllowedInactive-r18 is signalled in SIB1: - operates in eDRX with an eDRX cycle TeDRX, RAN configured by extendedPagingCycle-r18; - else if the UE is configured for eDRX by ran-ExtendedPagingCycle-r17 and eDRX-AllowedInactive-r17 is signalled in SIB1: - operates in eDRX with an eDRX cycle TeDRX, RAN configured by ran-ExtendedPagingCycle-r17; - else: - does not operate in eDRX. - If the UE operates in eDRX with an eDRX cycle no longer than 1024 radio frames, it monitors POs as defined in 7.1 with configured eDRX cycle. Otherwise, a UE operating in eDRX monitors POs as defined in 7.1 during a periodic Paging Time Window (PTW) configured for the UE. The PTW is UE-specific and is determined by a Paging Hyperframe (PH), a starting position within the PH (PTW_start) and an ending position (PTW_end).

[0073] At the 3GPP RAN#127bis meeting, regarding paging, the following contributions were submitted, including the following extracts: R2-2408108, Huawei, HiSilicon, Turkcell, China Southern Power Grid: “If the satellite does not receive any MT data when feeder link is available, the satellite does not need to page UE when service link is available. And the UE doesn’t needs to monitor paging or initiate RRC connection in this case. Therefore, if UE is informed when the NW does not have any MT data buffered for an area, the UE does not need to monitor the paging or initiate RRC connection, which saves UE power.”. R2-2408282, Honor: “For CN-initiated paging, the MME-ground sends paging message to the satellites that are going to visit the UE’s tracking areas, when the feeder link becomes available. But for UE, before starting to monitor paging, the UE needs to decide whether there is a need to monitor paging. Since the last time the UE monitored paging, if the satellite has never connected to MME-ground, the UE can skip paging monitoring. Therefore, the information about the last time the feeder link was available should be provided for UE to decide whether to monitor paging”.

[0074] One issue with the above proposals in the contributions is that, while it may be beneficial for the UE to stop monitoring paging messages in some scenarios, it is also possible that due to propagation delay in the feeder link, a paging message that was initiated from the Core Network before the feeder link became unavailable still reaches the UE. In this case, there would be unnecessary resources lost as the eNB / gNB would try to page the UE again in the future and send any pending MT data for transmission. This would also create unnecessary delays for the UE to receive the MT data. In case the UE moves from one cell to another during S&F operation, the MT data would be lost due to the absence of inter-satellite links in S&F deployments.

[0075] To the knowledge of the present inventors, existing solutions to solve the conflicting issues above have not been discussed in 3GPP. The existing techniques are based on transfer of MT data from one eNB / gNB to another but upon absence of inter-satellite links this is not possible.

[0076] One key idea of embodiments in the present disclosure is that if the UE assesses a trigger that leads to stop monitoring paging, it still monitors paging for one or more additional paging occasion(s), after which it stops monitoring paging.

[0077] The embodiments in the present disclosure may allow a trade-off between saving battery in the UE, and resource and service efficiency. It may also prevent from losing MT data that is stored in the satellite’s transmitter buffer while it transitions to S&F operating mode.

[0078] Note that, in the present disclosure, “user,” “user segment,” “UE,” and the like may be used interchangeably. In the present disclosure, “S&F mode,” “non-real-time mode,” “delay-tolerant mode,” “regenerative mode,” “barred mode,” “first mode,” and the like may be used interchangeably. In the present disclosure, “real-time mode,” “non-S&F mode,” “transparent mode,” “non-barred mode,” “second mode,” and the like may be used interchangeably.

[0079] <Method> The methods (wireless (or radio) communication methods, control methods) described below may be applied in the system 1 described above. A transmitter (or receiver) in the methods may be the UE 10 and may be considered as a UE. A receiver (or transmitter) in the methods may be the BS 20 and may be considered as a BS.

[0080] The present disclosure may disclose a method and apparatus for efficient power and resource savings in a radio communication system.

[0081] The method can be applied to any wireless communication system but, in the rest of the disclosure, the method is exemplified with, but not limited to, non-terrestrial mobile radio communication systems, such as 3GPP LTE and / or NR radio access technology.

[0082] In one embodiment, the UE may determine, on the basis of a condition, whether the UE stops monitoring Paging after a specific timing. FIG. 5 shows a schematic diagram illustrating an exemplary flow chart of a procedure for stopping monitoring Paging in one embodiment in the present disclosure.

[0083] In step S101, the UE checks whether the condition becomes valid.

[0084] If the condition becomes valid (step S101-Yes), the UE stop monitoring Paging after a specific timing in step S102. If the condition does not become valid (step S101-No), the UE keeps monitoring Paging, i.e., the UE does not stop monitoring Paging after a specific timing in step S103. Note that the UE may stop monitoring Paging immediately in the step S103.

[0085] In one embodiment, monitoring Paging may be defined by monitoring one or more of: paging channel(s) (e.g., PCH, PDSCH conveying PCH (or paging message)) and control channel(s) [for paging [DCI]] (e.g., PDCCH, MPDCCH, NPDCCH).

[0086] In one embodiment, monitoring Paging may be defined by monitoring [reception of] one or more of: paging message, paging DCI, paging indication (e.g., Early Paging Indication (EPI)), and paging notification.

[0087] In one embodiment, if the condition becomes valid (the condition is met), the UE may stop monitoring Paging after having monitored N paging occasion(s). In this case, the specific timing may be the time when the UE has monitored N paging occasion(s) after the condition becomes valid.

[0088] In the present disclosure, N may be a positive integer. The value of N from the embodiments in the present disclosure may be provided from another node to the UE, for example from a network node, or a UE. The value of N may be pre-configured in the UE, for example via Subscriber Identity Module (SIM) toolkit.

[0089] In one embodiment, if the condition becomes valid, the UE may stop monitoring Paging after having monitored N paging frame(s) or N paging hyperframe(s).

[0090] In one embodiment, if the condition becomes valid, the UE may stop monitoring Paging after having monitored N paging subframe(s).

[0091] In one embodiment, if the condition becomes valid, the UE may stop monitoring Paging after having monitored N paging slot(s).

[0092] In one embodiment, if the condition becomes valid, the UE may stop monitoring Paging after having monitored N DRX cycles(s) or N extended DRX (eDRX) cycles(s).

[0093] In one embodiment, if the condition becomes valid, the UE may stop monitoring Paging after [at least one of] radio bearers are released.

[0094] In one embodiment, if the condition becomes valid, the UE may start a timer (or second timer) and stop monitoring Paging after the timer expires. The timer may be a timer regarding stopping monitoring Paging. The timer value may be configurable, pre-configurable, or hard coded in the specification.

[0095] In one embodiment, the condition [from above] may be the [re-]start or the expiry of a timer (or first timer). The timer may be a timer regarding DRX or eDRX (e.g., drx-onDurationTimer). The timer value may be configurable, pre-configurable, or hard coded in the specification.

[0096] In one embodiment, the condition [from above] may be the reception of a message. The message may be a specific system information broadcast message (e.g., MIB, SIB1, SIBX (X is an integer)) or a specific message such as RRC reconfiguration message. The information on the value of above N, the first timer value and / or the second timer value may be included in the message or transmitted along with the message.

[0097] In one embodiment, the condition [from above] may be [the reception of] an indication that the BS (e.g., eNB / gNB) does not have [enough] MT data. The information on the value of above N, the first timer value and / or the second timer value may be included in the indication or transmitted along with the indication.

[0098] In one embodiment, the condition [from above] may be [the reception of] an indication that the satellite, or BS (e.g., eNB / gNB), has not been connected to the Core Network, or MME, since the last time the UE monitored paging. The information on the value of above N, the first timer value and / or the second timer value may be included in the indication or transmitted along with the indication.

[0099] In one embodiment, the condition [from above] may make use of information about the last time when the feeder link was available. For example, the condition [from above] may be the current time is M frame / subframe / slot / second larger than the last time when the feeder link was available. In the present disclosure, M may be a positive integer. The value of M may be derived / obtained as mentioned previously regarding the value of N.

[0100] In one embodiment, the condition [from above] may be [the reception of] an indication of stopping monitoring Paging. The information on the value of above N, the first timer value and / or the second timer value may be included in the indication or transmitted along with the indication.

[0101] While the example embodiments in the present disclosure relate to the UE, embodiments in the present disclosure may be implemented by any node.

[0102] While the example embodiments in the present disclosure relate to the Core Network example of MME, other Core Network nodes are possible, for example AMF.

[0103] While the example embodiments in the present disclosure relate to the example S&F mode, embodiments in the present disclosure are not limited to the S&F mode and may be implemented for any scenario.

[0104] The features and result of some embodiments in the present disclosure include radio and software installed in a node (e.g., vehicle, road-side unit, base station, smartphone, mobile device). Also, methods and apparatus in this invention may be used for future radio access technologies using similar mechanisms (e.g., 6G).

[0105] <Abbreviations> At least some of the following abbreviations may be used in the present disclosure. If there is an inconsistency between abbreviations, preference should be given to how it is used in the present disclosure. If listed multiple times below, the first listing may be preferred over any subsequent listing(s). AMF: Access and Mobility Management Function DCI: Downlink Control Information DRX: Discontinuous Reception MME: Mobility Management Entity MPDCCH: MTC Physical Downlink Control Channel MTC: Machine Type Communication NPDCCH: Narrowband Physical Downlink Control channel NTN: Non-Terrestrial Network PCH: Paging Channel PDCCH: Physical Downlink Control Channel PDSCH: Physical Downlink Shared Channel PF: Paging Frame PO: Paging Occasion P-RNTI: Paging RNTI RNTI: Radio Network Temporary Identifier UE: User Equipment

[0106] <Supplementary Notes> Regarding embodiments of the present disclosure, the following supplementary notes are given. <Supplementary Note 1> A terminal comprising: a receiver configured to monitor paging; and a processor configured to control the receiver to stop monitoring of the paging after a specific timing, when a condition for stopping monitoring of the paging is met. <Supplementary Note 2> The terminal according to supplementary note 1, wherein the specific timing is a time after monitoring one or more paging occasions. <Supplementary Note 3> The terminal according to any one of supplementary notes 1 to 2, wherein the specific timing is a time after a timer expires, the timer being started when the condition is met. <Supplementary Note 4> The terminal according to any one of supplementary notes 1 to 3, wherein the specific timing is a time after monitoring one or more Discontinuous Reception (DRX) cycles. <Supplementary Note 5> The terminal according to any one of supplementary notes 1 to 4, wherein the specific timing is a time after at least one of radio bearers is released. <Supplementary Note 6> The terminal according to any one of supplementary notes 1 to 5, wherein the condition is met upon reception of a specific message. <Supplementary Note 7> The terminal according to any one of supplementary notes 1 to 6, wherein the condition is met upon reception of an indication that a base station does not have mobile terminated (MT) data for the terminal. <Supplementary Note 8> The terminal according to any one of supplementary notes 1 to 7, wherein the condition is met upon reception of an indication that a base station has not been connected to a core network since a last time the terminal monitored the paging. <Supplementary Note 9> The terminal according to any one of supplementary notes 1 to 8, wherein the condition is based on information about a last time a feeder link was available. <Supplementary Note 10> The terminal according to any one of supplementary notes 1 to 9, wherein the paging includes a paging channel or a paging message. <Supplementary Note 11> A method performed by a terminal, the method comprising: monitoring paging; and stopping the monitoring of the paging after a specific timing, when a condition for stopping monitoring of the paging is met. <Supplementary Note 12> A base station comprising: a processor configured to generate information for controlling a timing at which a terminal stops monitoring of paging; and a transmitter configured to transmit the information to the terminal, wherein the information causes the terminal to stop monitoring of the paging after a specific timing, when a condition for stopping the monitoring of the paging is met at the terminal. <Supplementary Note 13> A communication system comprising a terminal according to any one of supplementary notes 1 to 10 and a base station according to supplementary note 12.

[0107] <Variations> Embodiments in the present disclosure may be used for any 3GPP radio access technologies, for example, 3GPP 4G technology referred to as Long Term Evolution (LTE), 3GPP 5G technology referred to as New Radio (NR) or future 3GPP radio technology generations such as 6G or 7G. While the examples in the present disclosure relate to 3GPP technologies, embodiments in the present disclosure could be used for non-3GPP technologies, for example, Bluetooth, Institute of Electrical and Electronics Engineers (IEEE) and its 802.11 variants, Wi-Fi, Worldwide Interoperability for Microwave Access (WiMAX), etc.

[0108] In the present disclosure, any signals (e.g., for indication, configuration and notification of some information) from a node to another node may be transmitted using any one or combinations of Radio Resource Control (RRC) layer signaling, Medium Access Control (MAC) layer signaling, and physical (PHY) layer signaling, even if not explicitly stated.

[0109] The RRC layer signaling may be an RRC message or an RRC information element. The MAC layer signaling may be a MAC control element (MAC CE) or a MAC Protocol Data Unit (PDU). The PHY layer signaling may be downlink control information (DCI), uplink control information (UCI), or sidelink control information (SCI).

[0110] Furthermore, a BS in the present disclosure may be interpreted as a UE. For example, each embodiment of the present disclosure may be applied to the case where a communication between a BS and a UE is replaced with a communication between a plurality of UEs. In the case, the UE may have the functions of the BS described above. In the case, "uplink" and "downlink" may be interpreted as a UE-to-UE link (for example, "sidelink"). For example, an uplink channel, a downlink channel and so on may be interpreted as a sidelink channel.

[0111] Any parameters, values and information in the present disclosure may be indicated from a node to another node, even if not explicitly stated. In the present disclosure, “X” and “information on X” may be used interchangeably.

[0112] In the present disclosure, a time unit for radio communication may be replaced with (or interchangeably used as) another time unit for radio communication. For example, a radio frame (frame), a hyper frame, a subframe, a slot, a sub-slot, and a symbol all express time units for radio communication.

[0113] In the present disclosure, the terms “notify,” “report,” “indicate,” “designate,” “activate,” “deactivate,” “select,” “configure,” “pre-configure,” “update,” “determine,” and any variation of the terms may be read interchangeably.

[0114] In the present disclosure, "equal to or smaller than," "smaller than," "equal to or larger than," "larger than," "equal to," and the like may be interchangeably used. In the present disclosure, words such as "good," "bad," "much," "little," "large," "small," "high," "low," "early," "late," "wide," "narrow," and the like may be interchangeably used irrespective of positive degree, comparative degree, and superlative degree. In the present disclosure, the words (such as "good," "bad," ...) and expressions obtained by adding "i-th" (i is any integer) to the words may be interchangeably used irrespective of positive degree, comparative degree, and superlative degree (for example, "best" may be interpreted as "i-th best," and vice versa).

[0115] In the present disclosure, "of," "for," "regarding," "related to," "associated with," and the like may be used interchangeably.

[0116] As used in the present disclosure, use of the term “or” in a list of items indicates an inclusive list. The list of items may be prefaced by a phrase such as “at least one of” or “one or more of.” For example, a list of at least one of A, B, or C includes A or B or C or AB (i.e., A and B) or AC or BC or ABC (i.e., A and B and C). Also, as used in the present disclosure, prefacing a list of conditions with the phrase “based on” shall not be construed as “based only on” the set of conditions and rather shall be construed as “based at least in part on” the set of conditions. For example, an outcome described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure.

[0117] In the present disclosure, the terms “comprise,” “include,” or “contain” may be used interchangeably and have the same meaning and are to be construed as inclusive and open-ended. The terms “comprise,” “include,” or “contain” may be used before a list of elements and indicate that at least all of the listed elements within the list exist but other elements that are not in the list may also be present. For example, if A comprises B and C, both {B, C} and {B, C, D} are within the scope of A.

[0118] The present disclosure, in connection with the accompanied drawings, describes example configurations that are not representative of all the examples that may be implemented or all configurations that are within the scope of the present disclosure. The term “exemplary” should not be construed as “preferred” or “advantageous compared to other examples” but rather “an illustration, an instance or an example.” By reading the present disclosure, including the description of the embodiments and the drawings, it will be appreciated by a person of ordinary skills in the art that the technology disclosed herein may be implemented using alternative embodiments. The person of ordinary skill in the art would appreciate that the embodiments, or certain features of the embodiments described herein, may be combined to arrive at yet other embodiments for practicing the technology described in the present disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

[0119] The flowcharts and block diagrams in the figures illustrate examples of the architecture, functionality, and operation of possible implementations of systems, methods, and devices according to various embodiments. It should be noted that, in some alternative implementations, the functions noted in blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Likewise, additional steps may be included in such methods, and certain steps may be omitted or combined, in methods consistent with various embodiments.

[0120] It is understood that the described embodiments are not mutually exclusive, and elements, components, materials, or steps described in connection with one example embodiment may be combined with, or eliminated from, other embodiments in suitable ways to accomplish desired design objectives. Any embodiment (two or more) used in the present disclosure may be used in combination.

[0121] Reference herein to “some embodiments” or “some exemplary embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment. The appearance of the phrases “one embodiment,” “some embodiments” or “another embodiment” in various places in the present disclosure do not all necessarily refer to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive of other embodiments. In the present disclosure, “an / one embodiment,” “(some) embodiments” and “another embodiment” may be used interchangeably.

[0122] The articles “a” and “an” as used in the present disclosure and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form.

[0123] Unless explicitly stated otherwise, each numerical value and range in the present disclosure may be interpreted as being approximate as if the word “about” or “approximately” preceded the value of the value or range.

[0124] The term "connected" or any variation of the term as used in the present disclosure mean all direct or indirect connections between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" to each other. The connection between the elements may be physical, logical, or a combination thereof. For example, "connection" may be interpreted as "access."

[0125] Although the elements in the following method claims, if any, are recited in a particular sequence, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.

[0126] It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the present disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment of the present disclosure. Certain features described in the context of various embodiments are not essential features of those embodiments, unless noted as such.

[0127] It will be further understood that various modifications, alternatives, and variations in the details, materials, and arrangements of the parts which have been described and illustrated in order to explain the nature of described embodiments may be made by those skilled in the art without departing from the scope. Accordingly, the following claims embrace all such alternatives, modifications, and variations that fall within the terms of the claims.

Claims

1. A terminal comprising: a receiver configured to monitor paging; and a processor configured to control the receiver to stop monitoring of the paging after a specific timing, when a condition for stopping monitoring of the paging is met.

2. The terminal according to claim 1, wherein the specific timing is a time after monitoring one or more paging occasions.

3. The terminal according to claim 1, wherein the specific timing is a time after a timer expires, the timer being started when the condition is met.

4. The terminal according to claim 1, wherein the specific timing is a time after monitoring one or more Discontinuous Reception (DRX) cycles.

5. The terminal according to claim 1, wherein the specific timing is a time after at least one of radio bearers is released.

6. The terminal according to claim 1, wherein the condition is met upon reception of a specific message.

7. The terminal according to claim 1, wherein the condition is met upon reception of an indication that a base station does not have mobile terminated (MT) data for the terminal.

8. The terminal according to claim 1, wherein the condition is met upon reception of an indication that a base station has not been connected to a core network since a last time the terminal monitored the paging.

9. The terminal according to claim 1, wherein the condition is based on information about a last time a feeder link was available.

10. The terminal according to claim 1, wherein the paging includes a paging channel or a paging message.

11. A method performed by a terminal, the method comprising: monitoring paging; and stopping the monitoring of the paging after a specific timing, when a condition for stopping monitoring of the paging is met.

12. A base station comprising: a processor configured to generate information for controlling a timing at which a terminal stops monitoring of paging; and a transmitter configured to transmit the information to the terminal, wherein the information causes the terminal to stop monitoring of the paging after a specific timing, when a condition for stopping the monitoring of the paging is met at the terminal.

13. A communication system comprising a terminal according to any one of claims 1 to 10 and a base station according to claim 12.

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