Terminal, method, base station and communication system

Abstract

A terminal according to one aspect of the present disclosure comprising: a receiver; a transmitter configured to transmit an uplink wake-up signal (UL WUS); and a processor configured to: perform a listen-before-request (LBR) operation by using the receiver to monitor for at least one of an acknowledgment (ACK) for a UL WUS from another terminal or a System Information Block 1 (SIB1); and when the at least one of the ACK or the SIB1 is detected through the LBR operation, control the transmitter to not transmit a UL WUS. According to one aspect of the present disclosure, reducing inefficient use of radio resources and / or unnecessary signaling overhead 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 / 737,263, filed on December 20, 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 wake-up signal transmission for network energy saving.

[0003] To achieve network energy savings, on-demand transmission of a System Information Block 1 (SIB1) has been studied in Third Generation Partnership Project (3GPP) (Non Patent Literature 1). A user Equipment (UE) in an idle or inactive mode transmits a wake-up signal (WUS) to a base station to request the SIB1, and the base station transmits the SIB1 in response to the request.

[0004] 3GPP TR 38.864 V18.1.0 (2023-03), “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Study on network energy savings for NR (Release 18)”

[0005] However, a problem arises with studied approaches to date when multiple UEs in the same area attempt to acquire the SIB1 at around the same time. This situation can lead to redundant WUS transmissions from each of the UEs and independent acknowledgment (ACK) transmissions from the base station for each request, resulting in inefficient use of radio resources and unnecessary overhead.

[0006] Therefore, one object of the present disclosure is to provide a terminal, a method, a base station and a communication system that can solve the aforementioned problems, or can reduce inefficient use of radio resources and / or unnecessary signaling overhead.

[0007] A terminal according to one aspect of the present disclosure comprising: a receiver; a transmitter configured to transmit an uplink wake-up signal (UL WUS); and a processor configured to: perform a listen-before-request (LBR) operation by using the receiver to monitor for at least one of an acknowledgment (ACK) for a UL WUS from another terminal or a System Information Block 1 (SIB1); and when the at least one of the ACK or the SIB1 is detected through the LBR operation, control the transmitter to not transmit a UL WUS.

[0008] According to one aspect of the present disclosure, reducing inefficient use of radio resources and / or unnecessary signaling overhead can be achieved appropriately.

[0009] FIG. 1 is a schematic diagram illustrating a system for some embodiments of the present disclosure.

[0010] FIG. 2 is a schematic diagram illustrating an exemplary functional configuration of each device for some embodiments of the present disclosure.

[0011] FIG. 3 is a schematic diagram illustrating an exemplary hardware configuration of each device for some embodiments of the present disclosure.

[0012] FIG. 4 is a schematic diagram illustrating an exemplary cases of on-demand SIB1 discussed by working groups.

[0013] FIG. 5 is a conceptual flow diagram to enable on-demand SIB1 on NES Cell in 3GPP Rel-19.

[0014] FIG. 6 is a schematic diagram illustrating an exemplary timeline to determine SIB1 monitoring window.

[0015] FIG. 7 is a schematic diagram illustrating an exemplary time window for type 0 PDCCH monitoring.

[0016] FIG. 8 is a schematic diagram illustrating an exemplary timeline for obtaining OD-SIB1 in one embodiment in the present disclosure.

[0017] The present disclosure may introduce a method and apparatus for wake-up signal transmission for network energy saving.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] <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.

[0022] 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.

[0023] 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.

[0024] In the present disclosure, a UE, a mobile station, a mobile node and a terminal may be used interchangeably.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] Each BS 20 may form its cell. A cell may denote an area where the UE 10 can communicate with the BS 20. For example, in a cell, the UE 10 may receive downlink signal from the BS 20 that form the cell. The UE 10 may communicate with one or more BS 20 using one or more cells.

[0029] The core network 30 may include at least one of Evolved Packet Core (EPC), 5G Core Network (5GCN), and so on.

[0030] 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.

[0031] <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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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).

[0051] The network interface 940 may be, for example, a network adapter, which may be wired to an external network to send and receive signals.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] <On-demand system information block 1 (SIB1) transmissions> As mobile communication is advancing itself from 4G to 5G across many industries, denser networks, more antennas, larger bandwidths and more frequency bands are common solutions to support more advanced services and applications. However, all of these inevitably entails more energy consumption and operational cost, which collides with the well-accepted goal of environmental sustainability.

[0062] According to the report titled “5G energy efficiencies: Green is the new black” from GSMA, the energy cost on mobile networks accounts for ~23% of the total operator cost. Most of the energy consumption comes from the radio access network and in particular from the Active Antenna Unit (AAU). Therefore, improvements of network energy savings (NES) on radio access network are essential to get the energy consumption of mobile networks under control.

[0063] In a 3GPP Rel-18 study, such as 3GPP TR 38.864 V18.1.0, “Study on network energy savings for NR,” based on an agreed BS (base station) energy consumption model, and the evaluation methodology and assumptions, potential network energy saving techniques in various domains were evaluated with respect to the energy saving gains and the corresponding performance impact, while whether some specific KPIs such as UPT (User Perceived Throughput), access delay, UE (User Equipment) power consumption were also considered.

[0064] In the study, some techniques were found beneficial, primarily for RRC Connected UEs, user specific signals and channels, and low load scenarios; on the other hand, some other techniques also found to be beneficial were not yet specified in Rel-18, which includes on-demand SSB and on-demand SIB1 transmissions, as well as adaptation of common signal / channel transmissions.

[0065] The present disclosure may be aimed at on-demand SIB1 transmissions, especially for RRC IDLE / INACTIVE UEs, which have been in the scope of the work item on NES enhancements in 3GPP Rel-19.

[0066] In RP-242384, “Way forward on NES checkpoint (RAN1 Chair: Samsung)” in 3GPP RAN#105, it summarizes the contributions submitted to RAN#105 (September 2024) regarding the checkpoint for the approval of on-demand SIB1’s normative work as well as comments made during the first round of online discussions in RAN#105, where the cases discussed by working groups are illustrated in FIG. 4 and briefly explained as follows. FIG. 4 is a schematic diagram illustrating an exemplary cases of on-demand SIB1 discussed by working groups.

[0067] These cases are as follows: - Case 1: UE obtains UL WUS configuration from NES Cell, UE transmits UL WUS on NES Cell, UE receives on-demand SIB1 from NES Cell; - Case 2: UE obtains UL WUS configuration from Cell A, UE transmits UL WUS on NES Cell, UE receives on-demand SIB1 from NES Cell; - Case 3: UE obtains UL WUS configuration from Cell A, UE transmits UL WUS on Cell A, UE receives on-demand SIB1 from Cell A.

[0068] In the present disclosure, “UL WUS” denotes an uplink wake up signal, “Cell A” denotes a cell that is periodically transmitting at least its own SIB1, and “NES Cell” denotes a cell that may transmit SIB1 transmission in response to UL WUS from a UE.

[0069] In the present disclosure, Cell A may be a primary cell (PCell), a secondary cell (SCell), and any kind of cells. NES Cell may be a PCell, a SCell, and any kind of cells.

[0070] Finally in RAN#105, on-demand SIB1 was approved to enter normative phase from study phase with focus on case 2 only, with the following notes: - no modification of SSB will be discussed under this objective; - RAN1 strives to minimize impact to legacy UE; - RAN1 specification impact to support this feature should be minimized.

[0071] To follow the above guidelines, a conceptual flow among Cell A, NES Cell and R19 UE can be depicted in FIG. 5 to highlight possible enhancements to legacy procedures, by which on-demand SIB1 can be possibly provided in compliance with the agreements made in 3GPP Rel-19. FIG. 5 is a conceptual flow diagram to enable on-demand SIB1 on NES Cell in 3GPP Rel-19.

[0072] The UE receives SSB of Cell A, SIB1 of Cell A and WUS configuration of NES Cell (WUS Cfg(N)). WUS Cfg(N) may be included in the SIB1 of Cell A. The UE transmits UL WUS on the NES Cell based on WUS Cfg(N) and receives ACK of the UL WUS. After receiving the ACK, the UE receives on-demand SIB1 from the NES Cell.

[0073] These possible enhancements have strong connection with the on-demand SIB1 transmission behavior in time domain, where following 3 agreements have already been made: Agreement At least for Case-2: For further study of type 0 PDCCH monitoring occasions for on demand SIB1, on the starting time and duration of the time window of type 0 PDCCH monitoring occasions, RAN1 to down select from the following two options: Option 1: starting time and duration are indicated in RAR of the UL-WUS transmission; Option 2: starting time and duration are indicated in the UL WUS configuration. Agreement At least for Case-2: For further study of type 0 PDCCH monitoring occasions for on demand SIB1, on reference time point to determine the window starting time, RAN1 to down select from the following options: Option 1: The reference time point is defined based on the RAR reception time of the UL-WUS transmission; Option 2: The reference time point is defined based on the UL-WUS transmission time; Option 3: The reference time point is defined based on the RAR window of the UL-WUS transmission. Agreement For Case-2: For type 0 PDCCH monitoring occasions for on demand SIB1, on how the search space zero configuration is provided, RAN1 to down select from the following options: Option 1: searchSpaceZero for on-demand SIB1 is provided from MIB on NES cell; Option 2: searchSpaceZero for on-demand SIB1 is provided from UL WUS configuration Option 3: searchSpaceZero for on-demand SIB1 is provided from the RAR of UL WUS.

[0074] In R1-2408677 titled “On-demand SIB1 for idle / inactive mode UEs” by LG Electronics in 3GPP RAN1#118-bis, an “actual” starting time of SIB1 monitoring window is defined so that the “actual” starting time can be after “indicated” starting time of SIB1 monitoring window to allow for reception flexibility of on-demand SIB1 from an NES cell. This design is illustrated in FIG. 6. FIG. 6 is a schematic diagram illustrating an exemplary timeline to determine SIB1 monitoring window.

[0075] In so doing, it proposes that: - the timer (or duration of time window) or a value of SIB1 transmission cycle N can be pre-defined / configured, or one of the candidate values can be directly indicated via the gNB's response (e.g., RAR) to the UL WUS; - the reference time point is defined based on the RAR reception time of the UL-WUS transmission; - For Type0-PDCCH CSS set configuration, at least support: searchSpaceZero for on-demand SIB1 is provided from the RAR of UL WUS.

[0076] This design based on the above proposals of R1-2408677 has issues. This design may work for serving Rel-19 UEs one after another, but will need extra work for simultaneously dealing with multiple Rel-19 UEs, including the avoidance of redundant UL WUS requests.

[0077] In R1-2408818 titled “On-demand SIB1 for UEs in idle / inactive mode for NES” by Ericsson in 3GPP RAN1#118-bis, an example on how the time domain behavior can be specified is illustrated in FIG. 7, where UE can start monitoring for on-demand SIB1 transmission after X SFNs relative to the time when the RAR to a UL WUS is sent, and when the value is provided in the RAR, it can enable the network to coordinate the reception of SIB1 by multiple UEs.

[0078] In so doing, it proposes that: - starting time and duration indicated in RAR of the UL-WUS transmission is supported; - the reference time point defined based on the RAR reception time of the UL-WUS transmission is supported; - RAN1 consider searchSpaceZero and controlResourceSetZero for on-demand SIB1 provided from MIB on NES cell or from the UL WUS configuration.

[0079] This design based on the above proposals of R1-2408818 has issues. This design may work for simultaneously serving multiple Rel-19 UEs, but will need extra work to deal with the avoidance of and redundant UL WUS requests and multiple RARs.

[0080] For now, there are at least two issues that might bring overhead to the introduction of on-demand SIB1 based on legacy procedures: (1) redundant UL WUS requests from UEs; (2) independent ACK to each UL WUS request from UE.

[0081] Some embodiments in the present disclosure may provide the way to address one or both of the above two issues.

[0082] <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.

[0083] The present disclosure discloses a method and apparatus for on-demand SIB1 (OD-SIB1) for Network Energy Saving.

[0084] In the present disclosure, “Rel-19 UE” and “UE” may be used interchangeably. The UE may not be restricted with Rel-19 UE and may be later-release UE. In the present disclosure, “NES Cell” and a first BS may be used interchangeably. In the present disclosure, “Cell A” and a second BS may be used interchangeably. The first BS and the second BS may be different BSs or the same BS.

[0085] In the present disclosure, “UL WUS,” “UL WUS request” and “[OD-]SIB1 request” may be used interchangeably. UL WUS may be transmitted using random access (RA), RA preamble, PRACH, and the like.

[0086] In the present disclosure, wordings related to “initiate” and “transmit” may be used interchangeably. In the present disclosure, “SIB1,” “OD-SIB1,” and the other information, e.g., the other system information (MIB, SIBs) may be used interchangeably.

[0087] In one embodiment, if the UE has SIB1 request configuration of an NES Cell, the UE may perform at least one of the following: (1) the UE checks if SIB1 is currently being broadcasted or provided on demand for that cell before requesting SIB1 of that cell; and (2) the UE checks if ACK to UL WUS has been provided for that cell before requesting SIB1 of that cell.

[0088] Therefore, one embodiment may introduce at least one of the following features: (1) checking or listen-before-request (LBR) for ACK to UL WUS or SIB1 before any OD-SIB1 request, e.g., random access (RA); (2) modified (or extended) ACK, e.g., random access response (RAR), made known to other UEs ready to send their UL WUSes.

[0089] For example, the UE may perform LBR before UL-WUS transmission and may skip UL-WUS transmission upon receiving the modified ACK or SIB1.

[0090] In one embodiment, the LBR may mean reception, monitoring or detection of ACK to UL WUS and / or SIB1 before transmitting UL WUS.

[0091] In one embodiment, modified (or extended) ACK may be transmitted using RAR, PDSCH, PDCCH, reference signal, and the like. In the present disclosure, wordings related to “modified [N]ACK,” “extended [N]ACK,” “[N]ACK,” “RAR,” and “[BS’s] response” may be used interchangeably.

[0092] An illustration of one embodiment in the present disclosure is depicted in FIG. 8. In this example of FIG. 8, there are three UEs (UE1, UE2, UE3) on the NES Cell. The UE1 performs LBR for the duration of LBR1. The UE2 performs LBR for the duration of LBR2. The UE3 performs LBR for the duration of LBR3. Note that in this example the starting times of three LBRs are different but the starting times of two LBRs for different UEs may be the same.

[0093] The UEs may obtain the duration of their LBRs by configuration (e.g., UL-WUS configuration) or from SSB periodicity.

[0094] Before time t1, for there is no UL WUS request from any UEs, the NES Cell stays in NES state (No-WUS Period, with NACK indication), with only its SSBs regularly delivered.

[0095] At time t1, according to the WUS configuration information received from Cell A, when the UE1 learns from its LBR (LBR1) that it is the first UE sending UL WUS to the NES Cell (No-WUS Period, with NACK indication), the NES Cell will acknowledges with required information via RAR and indicate the ACK status in specified duration (entering WUS / ACK Period, still in NES state, but with ACK indication) until the starting time of OD-SIB1 Period (Non-NES) is reached, after which the UE1 starts to monitor OD-SIB1.

[0096] At time t2, if the UE2 learns from its LBR (LBR2) that a previous UL WUS has been accepted (WUS / ACK Period, with ACK indication), it will not send its UL WUS to the NES Cell (“X” in the FIG. 8 means “UE does not transmit / receive that signal) and wait until the starting time of OD-SIB1 Period (Non-NES) after which it starts to monitor OD-SIB1.

[0097] Note that once the UE1 / UE2 successfully receives RAR (ACK), they may skip receiving RAR (ACK) until the starting time of OD-SIB1 Period.

[0098] At time t3, when the NES Cell enters OD-SIB1 Period and starts to deliver OD-SIB1 with its state changed to Non-NES state, if the UE3 learns from its LBR (LBR3) that SIB1 is currently being broadcasted or provided on demand for the NES Cell (OD-SIB1 Period, in Non-NES state, with NACK indication), it can directly decode the SIB1 of NES Cell based on Type0-PDCCH CSS set configuration acquired, without the need to send its UL WUS nor to retrieve the ACK status. After the OD-SIB1 duration is expired, everything is reset to that of before [next] time t1.

[0099] In one embodiment, No-WUS Period, a period with NACK indication and the first period may be used interchangeably. In one embodiment, WUS / ACK Period, a period with ACK indication and the second period may be used interchangeably. In one embodiment, OD-SIB1 Period, a period with [OD-]SIB1 transmission and the third period may be used interchangeably.

[0100] In one embodiment, Type0-PDCCH CSS set and the other search space set may be used interchangeably.

[0101] As shown in FIG. 8, some embodiment in the present disclosure may proposes that: - the starting time and duration may be indicated in RAR of the UL-WUS transmission or in the UL WUS configuration; - the reference time point may be defined based on the RAR reception time of the UL-WUS transmission (if relative) or the same as the starting time (if absolute) in the UL WUS configuration; - Type0-PDCCH CSS set configuration may be provided from MIB on NES cell (at least), UL WUS configuration (at least) or the RAR of UL WUS.

[0102] They have compliance with various options currently being discussed, where a number of necessary operations on the NES Cell as well as the Rel-19 UE need to get involved, including operations for the NES Cell and operations for the Rel-19 UE.

[0103] For example, according to the information specified in the UL WUS configuration, the NES Cell may perform at least one of the following operations: (1) in WUS / ACK Period (NES), when a first OD-SIB1 request (UL WUS) is received from R19 UE, the NES Cell may acknowledge with required information via RAR and may indicate the ACK status in specified duration until the starting time of OD-SIB1 Period (Non-NES) is reached, (2) in OD-SIB1 Period (Non-NES), the NES Cell may enable Type0-PDCCH CSS set configuration by which camped on UEs can utilize to decode the SIB1 of the NES Cell, meanwhile changing its state to Non-NES, (3) when the stop time of OD-SIB1 Period (Non-NES) is reached, the NES Cell may disable Type0-PDCCH CSS set configuration, meanwhile changing its state back to NES.

[0104] In one embodiment, enabling Type0-PDCCH CSS set configuration and transmitting PDCCH scheduling OD-SIB1 on Type0-PDCCH CSS set corresponding to the Type0-PDCCH CSS set configuration may be used interchangeably.

[0105] In one embodiment, disabling Type0-PDCCH CSS set configuration and suspending transmission of PDCCH scheduling OD-SIB1 on Type0-PDCCH CSS set corresponding to the Type0-PDCCH CSS set configuration may be used interchangeably.

[0106] Moreover, for example, according to the information specified in the UL WUS configuration, the Rel-19 UE may perform listen-before-request (LBR) at different moments. Based on the result of LBR, the Rel-19 UE may perform at least one of the following operations: (1) if OD-SIB1 Period (Non-NES) is detected, then the UE may decode the SIB1 of NES Cell based on Type0-PDCCH CSS set configuration acquired, (2) if ACK to UL WUS is detected, then the UE may wait until the starting time of OD-SIB1 Period (Non-NES) is reached to acquire Type0-PDCCH CSS set configuration to decode the SIB1 of NES Cell, with no UL WUS re-initiated, (3) if ACK to UL WUS is not detected, then the UE may initiate (or transmit) UL WUS to the NES Cell.

[0107] As explained above, the present disclosure may disclose improvements that may reduce the overhead to the introduction of OD-SIB1 based on legacy procedures, i.e., redundant UL WUS requests and / or independent ACK to each UL WUS request. Most of all, the improvements may work in compliance with various options currently being discussed.

[0108] <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). ACK: Acknowledgement CSS: Common Search Space LBR: Listen-Before-Request MIB: Master Information Block NACK: Negative Acknowledgement PDCCH: Physical Downlink Control Channel PDSCH: Physical Downlink Shared Channel PRACH: Physical Random Access Channel RAR: Random Access Response SIB: System Information Block SFN: System Frame Number UE: User Equipment UL WUS: Uplink Wake-Up Signal

[0109] <Supplementary Notes> Regarding embodiments of the present disclosure, the following supplementary notes are given. <Supplementary Note 1> A terminal comprising: a receiver; a transmitter configured to transmit an uplink wake-up signal (UL WUS); and a processor configured to: perform a listen-before-request (LBR) operation by using the receiver to monitor for at least one of an acknowledgment (ACK) for a UL WUS from another terminal or a System Information Block 1 (SIB1); and when the at least one of the ACK or the SIB1 is detected through the LBR operation, control the transmitter to not transmit a UL WUS. <Supplementary Note 2> The terminal according to supplementary note 1, wherein the processor is further configured to, when neither the ACK nor the SIB1 is detected through the LBR operation, control the transmitter to transmit the UL WUS. <Supplementary Note 3> The terminal according to any one of supplementary notes 1 to 2, wherein the processor is further configured to, when the ACK is detected, wait for a start of a transmission period of the SIB1 without transmitting the UL WUS. <Supplementary Note 4> The terminal according to any one of supplementary notes 1 to 3, wherein the processor is further configured to, when the SIB1 is detected, control the receiver to decode the SIB1 without transmitting the UL WUS. <Supplementary Note 5> The terminal according to any one of supplementary notes 1 to 4, wherein the LBR operation is performed based on configuration information received from a second base station, the second base station being different from a first base station that transmits the SIB1 on demand. <Supplementary Note 6> The terminal according to any one of supplementary notes 1 to 5, wherein the acknowledgment is a Random Access Response (RAR). <Supplementary Note 7> The terminal according to any one of supplementary notes 1 to 6, wherein the RAR indicates at least one of a starting time or a duration of a SIB1 monitoring window. <Supplementary Note 8> The terminal according to any one of supplementary notes 1 to 7, wherein the starting time of the SIB1 monitoring window is determined based on a reception time of the RAR. <Supplementary Note 9> The terminal according to any one of supplementary notes 1 to 8, wherein a duration of the LBR operation is provided to the terminal by a UL WUS configuration. <Supplementary Note 10> The terminal according to any one of supplementary notes 1 to 9, wherein the LBR operation comprises monitoring for an ACK indication transmitted by a base station, wherein the ACK indication is transmitted during a period after the base station has received an UL WUS. <Supplementary Note 11> A method performed by a terminal, the method comprising: performing a listen-before-request (LBR) operation to monitor for at least one of an acknowledgment (ACK) for an uplink wake-up signal (UL WUS) from another terminal or a System Information Block 1 (SIB1); and when the at least one of the ACK or the SIB1 is detected, not transmitting a UL WUS. <Supplementary Note 12> A base station comprising: a receiver configured to receive a first uplink wake-up signal (UL WUS) from a first terminal; a transmitter; and a processor configured to: control the transmitter to transmit an acknowledgment (ACK) for the first UL WUS, wherein the ACK is detectable by the first terminal and other terminals; and after transmitting the ACK, control the transmitter to transmit a System Information Block 1 (SIB1) on demand. <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.

[0110] <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.

[0111] 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.

[0112] 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).

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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).

[0118] In the present disclosure, "of," "for," "regarding," "related to," "associated with," and the like may be used interchangeably.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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."

[0128] 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.

[0129] 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.

[0130] 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; a transmitter configured to transmit an uplink wake-up signal (UL WUS); and a processor configured to: perform a listen-before-request (LBR) operation by using the receiver to monitor for at least one of an acknowledgment (ACK) for a UL WUS from another terminal or a System Information Block 1 (SIB1); and when the at least one of the ACK or the SIB1 is detected through the LBR operation, control the transmitter to not transmit a UL WUS.

2. The terminal according to claim 1, wherein the processor is further configured to, when neither the ACK nor the SIB1 is detected through the LBR operation, control the transmitter to transmit the UL WUS.

3. The terminal according to claim 1, wherein the processor is further configured to, when the ACK is detected, wait for a start of a transmission period of the SIB1 without transmitting the UL WUS.

4. The terminal according to claim 1, wherein the processor is further configured to, when the SIB1 is detected, control the receiver to decode the SIB1 without transmitting the UL WUS.

5. The terminal according to claim 1, wherein the LBR operation is performed based on configuration information received from a second base station, the second base station being different from a first base station that transmits the SIB1 on demand.

6. The terminal according to claim 1, wherein the acknowledgment is a Random Access Response (RAR).

7. The terminal according to claim 6, wherein the RAR indicates at least one of a starting time or a duration of a SIB1 monitoring window.

8. The terminal according to claim 7, wherein the starting time of the SIB1 monitoring window is determined based on a reception time of the RAR.

9. The terminal according to claim 1, wherein a duration of the LBR operation is provided to the terminal by a UL WUS configuration.

10. The terminal according to claim 1, wherein the LBR operation comprises monitoring for an ACK indication transmitted by a base station, wherein the ACK indication is transmitted during a period after the base station has received an UL WUS.

11. A method performed by a terminal, the method comprising: performing a listen-before-request (LBR) operation to monitor for at least one of an acknowledgment (ACK) for an uplink wake-up signal (UL WUS) from another terminal or a System Information Block 1 (SIB1); and when the at least one of the ACK or the SIB1 is detected, not transmitting a UL WUS.

12. A base station comprising: a receiver configured to receive a first uplink wake-up signal (UL WUS) from a first terminal; a transmitter; and a processor configured to: control the transmitter to transmit an acknowledgment (ACK) for the first UL WUS, wherein the ACK is detectable by the first terminal and other terminals; and after transmitting the ACK, control the transmitter to transmit a System Information Block 1 (SIB1) on demand.

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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