Wireless base station and terminal

Abstract

This wireless base station receives a measurement report from a terminal, and sets, on the basis of the measurement report, a plurality of candidate secondary cells to the terminal that the terminal can autonomously select.

Description

Wireless base station and terminal

[0001] The present disclosure relates to a radio base station and a terminal that contribute to reducing energy consumption in a network.

[0002] The 3rd Generation Partnership Project (3GPP: registered trademark) is developing specifications for the 5th generation mobile communication system (5G, also known as New Radio (NR) or Next Generation (NG)), and is also developing specifications for the next generation, known as Beyond 5G, 5G Evolution, or 6G.

[0003] For example, 3GPP Release 18 is studying a technology (NES: Network Energy Saving) to reduce the energy consumption of networks including radio base stations (gNBs) (Non-Patent Document 1). Specifically, studies are being conducted on transitioning cells formed by gNBs to a sleep state or applying DTX / DRX (Discontinuous Transmission / Discontinuous Reception), which performs intermittent transmission and reception by gNBs (Non-Patent Documents 2 and 3).

[0004] "New WID: Network energy savings for NR", RP-223540, 3GPP TSG RAN Meeting #98-e, 3GPP, December 2022"Report of 3GPP TSG RAN WG2 meeting #123, Toulouse, France",3GPP, August 2023"Status Report to TSG", RP-231926, 3GPP TSG RAN meeting #101, 3GPP, September 2023

[0005] Incidentally, a change of an existing secondary cell (SCell) (SCell change) is performed by sending SCell addition or SCell release from a gNB to a terminal (User Equipment, UE) through RRC signaling based on a measurement report from the UE. In other words, the UE cannot autonomously change the SCell.

[0006] Furthermore, when an SCell is an NES cell, it is desirable that normal UEs under the control of the cell be changed to another normal SCell when the NES mode of the SCell is activated. However, in the existing 3GPP specifications, it is necessary to execute a procedure to delete the NES mode SCell and add another normal SCell by RRC signaling from the gNB. In other words, the UE cannot autonomously change the NES SCell to another normal SCell.

[0007] Furthermore, when a primary / secondary cell (PSCell) in dual connectivity is an NES cell, it is desirable that normal UEs under the cell change (transition) to another normal PSCell when the NES mode of the PSCell is activated. In this case, a conditional PSCell addition change (CPAC) can be performed, but a specific method that takes into account the NES cell has not yet been developed.

[0008] Therefore, the following disclosure has been made in consideration of this situation, and aims to provide a radio base station and a terminal that can realize appropriate cell addition or modification, even when a technology for reducing network energy consumption (NES) is introduced.

[0009] One aspect of the present disclosure is a terminal (UE200) comprising a control unit (control unit 270) that controls cell transition of the terminal in accordance with mobility control by a lower layer, and a receiving unit (control signal / reference signal processing unit 240) that receives a message including an execution condition for the cell transition from a network, wherein the control unit executes the cell transition when a dormant execution condition that is applied when a source cell at the transition source or a candidate cell at the transition destination transitions to a dormant state is satisfied.

[0010] One aspect of the present disclosure is a radio base station (gNB100) comprising a receiving unit (control signal / reference signal processing unit 240) that receives measurement reports from a terminal (UE200), and a control unit (control unit 270) that configures the terminal with multiple secondary cell candidates that the terminal can autonomously select based on the measurement reports.

[0011] One aspect of the present disclosure is a terminal (UE200) that includes a receiving unit (control signal / reference signal processing unit 240) that receives lower layer signaling indicating that a secondary cell transitions to a dormant state due to a reduction in energy consumption, and a control unit (control unit 270) that deletes or deactivates the secondary cell when the signaling is received.

[0012] One aspect of the present disclosure is a radio base station (gNB100) comprising a communication unit (radio signal transceiver unit 210) that performs radio communication with a terminal via a secondary cell, and a control unit (control unit 270) that sets a priority for the secondary cell when setting a candidate for the secondary cell, wherein the control unit sets the priority based on at least one of the energy consumption cost in the secondary cell, the required communication quality, and the capabilities of the terminal.

[0013] FIG. 1 is a diagram showing an overall schematic configuration of a wireless communication system 10. FIG. 2 is a diagram showing an example configuration of a radio frame, a subframe, and a slot used in the wireless communication system 10. FIG. 3 is a functional block configuration diagram of a gNB 100 and a UE 200. FIG. 4 is a diagram showing an example configuration of a primary cell and a secondary cell. FIG. 5 is a diagram showing an example configuration sequence of an SCell according to an operation example 1. FIG. 6 is a diagram showing an example configuration sequence of an SCell according to an operation example 2. FIG. 7 is a diagram showing an example hardware configuration of a gNB 100 and a UE 200. FIG. 8 is a diagram showing an example configuration of a vehicle 2001.

[0014] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0015] (1) Overall Schematic Configuration of Wireless Communication System Fig. 1 is a diagram showing the overall schematic configuration of a wireless communication system 10 according to this embodiment. The wireless communication system 10 is a wireless communication system conforming to 5G New Radio (NR) and includes a Next Generation-Radio Access Network 20 (hereinafter, NG-RAN 20) and a terminal 200 (User Equipment 200, hereinafter, UE 200).

[0016] The wireless communication system 10 may be a wireless communication system conforming to a method called Beyond 5G, 5G Evolution, or 6G, or may include a wireless communication system conforming to a method called Long Term Evolution (LTE) or 4G. The wireless communication system 10 may support functions related to the Industrial Internet of Things (IIoT) and Ultra-Reliable and Low Latency Communications (URLLC).

[0017] The NG-RAN 20 includes a radio base station 100 (hereinafter, gNB 100). Note that the specific configuration of the radio communication system 10, including the number of gNBs (or eNBs, etc.) and UEs, is not limited to the example shown in FIG. 1 .

[0018] The gNB 100 may also employ a fronthaul (FH) interface defined by the Open Radio Access Network Alliance (O-RAN). The gNB 100 may include an O-RAN Distributed Unit (O-DU) and an O-RAN Radio Unit (O-RU). The gNB 100 can function as a type of NG-RAN node.

[0019] The NG-RAN 20 actually includes multiple NG-RAN nodes, specifically, gNBs (or ng-eNBs), and is connected to a 5G core network (5GC, not shown). The NG-RAN 20 and the 5GC may be simply referred to as a "network." The 5GC may introduce the concept of CUPS (Control and User Plane Separation), which clearly separates the functions of the user plane and the control plane.

[0020] The gNB100 is a radio base station conforming to NR and performs radio communication with the UE200 conforming to NR. The gNB100 may be configured to include a CU (Central Unit) and a DU (Distributed Unit), and the DU may be separated from the CU and installed in a different geographical location. One or more DUs may be connected to the CU. The gNB100 (gNB-CU) may be connected to each other via an Xn interface, and the CU and DU may be connected to each other via an F1 interface (such as an F1-AP).

[0021] The gNB100 and UE200 are capable of supporting Massive MIMO, which generates more directional beams by controlling radio signals transmitted from multiple antenna elements; Carrier Aggregation (CA), which aggregates and uses multiple component carriers (CCs); and Dual Connectivity (DC), which enables simultaneous communication between the UE and multiple NG-RAN nodes.

[0022] The type of DC may be Multi-RAT Dual Connectivity (MR-DC) that uses multiple radio access technologies, or NR-NR Dual Connectivity (NR-DC) that uses only NR. For example, one gNB may constitute a master node (MN), and one or more other gNBs may constitute secondary nodes (SNs).

[0023] The wireless communication system 10 may also support multiple frequency ranges (FR) as follows:

[0024] ・FR1: 410 MHz to 7.125 GHz ・FR2-1: 24.25 GHz to 52.6 GHz FR1 may use a sub-carrier spacing (SCS) of 15, 30, or 60 kHz and a bandwidth (BW) of 5 to 100 MHz. FR2-1 is a higher frequency than FR1 and may use a sub-carrier spacing (SCS) of 60 or 120 kHz (including 240 kHz) and a bandwidth (BW) of 50 to 400 MHz.

[0025] Note that SCS may be interpreted as numerology, which is defined in 3GPP TS38.300 and corresponds to one subcarrier spacing in the frequency domain.

[0026] Furthermore, the wireless communication system 10 also supports a frequency band higher than the FR2-1 frequency band. Specifically, the wireless communication system 10 supports a frequency band exceeding 52.6 GHz up to 71 GHz. Such a high frequency band may be referred to as FR2-2.

[0027] When using bands above 52.6 GHz, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) / Discrete Fourier Transform - Spread (DFT-S-OFDM) with larger Sub-Carrier Spacing (SCS) may be applied.

[0028] Additionally, as mentioned above, in high frequency bands such as FR2-2, increased inter-carrier phase noise becomes an issue, which may necessitate the application of a larger (wider) SCS or a single-carrier waveform.

[0029] The larger the SCS, the shorter the symbol / cyclic prefix (CP) period and slot period (assuming a 14 symbol / slot configuration is maintained). Figure 2 shows an example of the configuration of radio frames, subframes, and slots used in the wireless communication system 10.

[0030] If the 14-symbol / slot configuration is maintained, the larger (wider) the SCS, the shorter the symbol period (and slot period). The symbol period may also be called the symbol length, time direction, or time domain. The frequency direction may also be called the frequency domain, resource block, subcarrier, BWP (Bandwidth part), etc.

[0031] The frequency resources may include component carriers (CCs), subcarriers, resource blocks (RBs), resource block groups (RBGs), bandwidth parts (BWPs), etc. The time resources may include symbols, slots, minislots, subframes, radio frames, discontinuous reception (DRX) periods, etc.

[0032] The number of symbols constituting one slot does not necessarily have to be 14 (for example, 28 or 56 symbols). Also, the number of slots per subframe may differ depending on the SCS.

[0033] Furthermore, the wireless communication system 10 may support a conditional handover (CHO). In the CHO, a candidate cell for handover and a condition for executing a handover (which may also be called a transition) to the candidate cell are set in advance for the UE 200.

[0034] This allows the UE 200 to perform handover to the target radio base station (which may also be referred to as the target cell) without waiting for a handover instruction from the network.

[0035] CHO may be interpreted as a handover that is executed by the UE 200 when one or more execution conditions are satisfied. The UE 200 may start evaluating the execution conditions when it receives the CHO configuration and may stop evaluating the execution conditions when a handover (legacy handover or conditional handover) is executed.

[0036] A candidate gNB or a potential target gNB may provide a CHO configuration to the UE 200. The source gNB may provide execution conditions, such as the timing for triggering the CHO, to the UE 200. The execution conditions may consist of one or more trigger conditions.

[0037] In addition, two or more different triggers, such as RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), and SINR (Signal-to-Interference plus Noise power Ratio), may be set simultaneously to evaluate the CHO execution conditions of a candidate cell.

[0038] It should be noted that if CHO is configured in UE200 and UE200 receives another handover (HO) command from the gNB before the CHO execution condition is met, UE200 may trigger handover based on the received HO command and may not wait for the CHO condition to be met. In other words, the legacy HO configuration may take precedence over the CHO configuration (if configured).

[0039] In addition, in the wireless communication system 10, in addition to mobility management of the UE 200 at layer 3 (which may include, for example, a radio resource control layer (RRC)) (which may be called L3 mobility), mobility management at layer 1 / layer 2 (which may include, for example, a medium access control layer (MAC)) (which may be called LTM or L1 / L2 mobility) may be applied.

[0040] L3 Mobility may be interpreted as mobility control at the Radio Resource Control layer (RRC), while LTM may be interpreted as mobility control at the Physical layer (PHY), Medium Access Control layer (MAC), Radio Link Control layer (RLC), and Packet Data Convergence Protocol layer (PDCP).

[0041] In addition, in UE-based LTM, like conditional handover (CHO), the UE receives a specific execution condition from the radio base station (gNB), monitors the status according to the execution condition, and if the execution condition is satisfied, it may execute LTM.

[0042] In a broad sense, the mobility of UE200 may mean the ease of movement and maneuverability of UE200, but in this embodiment, it may also mean minimizing call drops, radio link (including beam) failures, unnecessary handovers, ping-pong states, etc.

[0043] The wireless communication system 10 may use an SSB (SS / PBCH Block) that is configured from a synchronization signal (SS) and a downlink physical broadcast channel (PBCH).

[0044] SSBs are transmitted periodically from the network mainly to allow UE 200 to detect cell IDs and reception timings when starting communication. In NR, SSBs are also used to measure the reception quality of each cell. The SSB transmission periodicity may be specified as 5, 10, 20, 40, 80, 160 milliseconds, etc. Note that the initial access UE 200 may assume a transmission period of 20 milliseconds.

[0045] The UE 200 transmits a measurement report (hereinafter, referred to as a Measurement report) including reception qualities for cells including a serving cell and neighboring cells to the network. The procedure by which the UE 200 transmits the Measurement report may be referred to as Measurement reporting. The reception qualities for the cells may include reception qualities of beams from the cells, or may include reception qualities of cells based on beams from the cells.

[0046] The UE 200 may perform measurement reporting periodically. The UE 200 may perform measurement reporting for each event. An entering condition for starting measurement reporting and a leaving condition for ending measurement reporting may be defined for each event. Existing events may include the following events (see 3GPP TS38.331):

[0047] (i) Event A1 Event A1 is an event in which the reception quality of the serving cell becomes better than a threshold. For example, the entering condition is Ms - Hys > Thresh, and the leaving condition is Ms + Hys < Thresh.

[0048] Here, Ms is the reception quality of the serving cell, Hys is a hysteresis parameter, and Thresh is a threshold value.

[0049] (ii) Event A2 Event A2 is an event in which the reception quality of the serving cell becomes worse than a threshold. For example, the entering condition is Ms + Hys < Thresh, and the leaving condition is Ms - Hys > Thresh.

[0050] Here, Ms is the reception quality of the serving cell, Hys is a hysteresis parameter, and Thresh is a threshold value.

[0051] (iii) Event A3 Event A3 is an event in which the reception quality of a neighboring cell is better than the reception quality of the serving cell by an offset. For example, the entering condition is Mn + Ofn + Ocn - Hys > Mp + Ofp + Ocp + Off, and the leaving condition is Mn + Ofn + Ocn + Hys < Mp + Ofp + Ocp + Off.

[0052] where Mn is the reception quality of the neighboring cell, Ofn is the offset specific to the measurement object, and Ocn is the offset specific to the cell. Mp is the reception quality of the serving cell, Ofp is the offset specific to the measurement object, and Ocp is the offset specific to the cell. Hys is the hysteresis parameter, and Off is the parameter used in Event A3.

[0053] (iv) Event A4 Event A4 is an event in which the reception quality of a neighboring cell becomes better than a threshold. For example, the entering condition is Mn + Ofn + Ocn - Hys > Thresh, and the leaving condition is Mn + Ofn + Ocn + Hys < Thresh.

[0054] where Mn is the reception quality of the neighboring cell, Ofn is an offset specific to the measurement object, Ocn is an offset specific to the cell, Hys is a hysteresis parameter, and Thresh is a threshold value.

[0055] (v) Event A5 Event A5 is an event in which the reception quality of the serving cell becomes worse than a threshold and the reception quality of a neighboring cell becomes better than a threshold. For example, the entering condition is Mp + Hys < Thresh1 and Mn + Ofn + Ocn - Hys > Thresh2, and the leaving condition is Mp - Hys > Thresh1 and Mn + Ofn + Ocn + Hys < Thresh2.

[0056] where Ms is the receiving quality of the serving cell, Hys is a hysteresis parameter, Thresh1 is a threshold, Mn is the receiving quality of the neighboring cell, Ofn is a measurement object-specific offset, and Ocn is a cell-specific offset, Hys is a hysteresis parameter, and Thresh2 is a threshold.

[0057] (vi) Event A6 Event A6 is an event in which the reception quality of a neighboring cell is better than the reception quality of a SCell (Secondary Cell) by an offset. For example, the entering condition is Mn + Ocn - Hys > Ms + Ocs + Off, and the leaving condition is Mn + Ocn + Hys < Ms + Ocs + Off.

[0058] In addition to the events described above, events related to RATs (Radio Access technologies) (e.g., B1 (Inter RAT neighbor becomes better than threshold), B2 (Serving becomes worse than threshold1 and inter RAT neighbor becomes better than threshold2)) may be included.

[0059] Here, Mn is the reception quality of the neighboring cell, Ocn is a cell-specific offset, Ms is the reception quality of the SCell, Ocs is a cell-specific offset, Hys is a hysteresis parameter, and Off is a parameter used in Event A6.

[0060] Furthermore, a technology (NES: Network Energy Saving) for reducing energy consumption of a network including a gNB may be introduced in the wireless communication system 10. The method of reducing energy consumption by NES is not particularly limited, but may typically include transitioning a cell to a sleep state, transitioning a cell formed by the gNB to a sleep state, DTX / DRX (Discontinuous Transmission / Discontinuous Reception) for intermittently transmitting and receiving data by the gNB 100, and the like.

[0061] The sleep state of a cell may mean that at least one of downlink (DL) transmission and uplink (UL) reception is not performed for a certain period of time, and the cell is in a dormant state. The DTX state may be interpreted as DL transmission by the gNB 100 being performed discontinuously at regular intervals, and the DRX state may be interpreted as UL reception by the gNB 100 being performed discontinuously at regular intervals. DTX / DRX may be activated or deactivated by downlink control information (DCI).

[0062] The sleep state and DTX / DRX state of the cell may be interpreted as the dormant state of the cell. The NES may also be applied to the cases of CHO and LTM.

[0063] (2) Functional Block Configuration of Wireless Communication System Next, a functional block configuration of the wireless communication system 10 will be described. Specifically, a functional block configuration of the UE 200 will be described. Fig. 3 is a functional block configuration diagram of the gNB 100 and the UE 200.

[0064] As shown in FIG. 3 , the UE 200 includes a radio signal transmitting / receiving unit 210, an amplifier unit 220, a modulation / demodulation unit 230, a control signal / reference signal processing unit 240, an encoding / decoding unit 250, a data transmitting / receiving unit 260, and a control unit 270.

[0065] It should be noted that Fig. 3 shows only the main functional blocks relevant to the description of the embodiment, and that the UE 200 (gNB 100) has other functional blocks (e.g., a power supply unit, etc.). Fig. 3 shows the functional block configuration of the UE 200, and for the hardware configuration, please refer to Fig. 7.

[0066] The radio signal transmitting and receiving unit 210 transmits and receives radio signals conforming to NR. The radio signal transmitting and receiving unit 210 can support Massive MIMO, which generates a more directional beam by controlling radio (RF) signals transmitted from multiple antenna elements, Carrier Aggregation (CA), which aggregates and uses multiple component carriers (CCs), and Dual Connectivity (DC), which simultaneously communicates between a UE and two NG-RAN nodes.

[0067] The amplifier unit 220 is configured by a PA (Power Amplifier) / LNA (Low Noise Amplifier), etc. The amplifier unit 220 amplifies the signal output from the modulation / demodulation unit 230 to a predetermined power level. The amplifier unit 220 also amplifies the RF signal output from the radio signal transmission / reception unit 210.

[0068] The modem unit 230 performs data modulation / demodulation, transmission power setting, resource block allocation, etc. for each predetermined communication destination (e.g., gNB 100). The modem unit 230 may apply Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) / Discrete Fourier Transform - Spread (DFT-S-OFDM). Furthermore, DFT-S-OFDM may be used not only for the uplink (UL) but also for the downlink (DL).

[0069] The control signal and reference signal processor 240 executes processing related to various control signals transmitted and received by the UE 200 and processing related to various reference signals transmitted and received by the UE 200 .

[0070] Specifically, the control signal / reference signal processing unit 240 receives various control signals, for example, control signals of a radio resource control layer (RRC), transmitted via a predetermined control channel from the gNB 100. In addition, the control signal / reference signal processing unit 240 transmits various control signals to the gNB 100 via a predetermined control channel.

[0071] The control signal and reference signal processor 240 performs processing using reference signals (RS) such as a Demodulation Reference Signal (DMRS) and a Tracking Reference Signal (TRS).

[0072] The DMRS is a reference signal (pilot signal) known between the base station and the terminal for estimating the fading channel used for data demodulation, while the TRS is a reference signal used to track time and frequency fluctuations in the downlink.

[0073] In addition to DMRS and TRS, the reference signals may also include Channel State Information-Reference Signal (CSI-RS), Sounding Reference Signal (SRS), and Positioning Reference Signal (PRS) for position information.

[0074] The channels include a control channel and a data channel. The control channels may include a Physical Downlink Control Channel (PDCCH), a Physical Uplink Control Channel (PUCCH), a Random Access Channel (RACH, Downlink Control Information (DCI) including a Random Access Radio Network Temporary Identifier (RA-RNTI)), a Physical Broadcast Channel (PBCH), etc.

[0075] Furthermore, the data channel includes a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH), etc. Data may refer to data transmitted via a data channel.

[0076] Furthermore, the control signal and reference signal processor 240 may perform processing related to transmission and reception of messages and commands related to CHO, LTM, and NES. Specifically, the control signal and reference signal processor 240 may receive a message including an execution condition for cell transition (handover) according to LTM from the network. In this embodiment, the control signal and reference signal processor 240 may constitute a receiver.

[0077] More specifically, the control signal / reference signal processing unit 240 may receive an RRC Reconfiguration from the network (gNB100) that includes at least one of an execution condition associated with when NES is not applied (which may also be called a normal LTM execution condition) and an execution condition associated with when NES is applied (which may also be called an NES execution condition).

[0078] The NES execution condition may be interpreted as a sleep execution condition that is applied when a source cell or a candidate cell transitions to a sleep state according to the NES. The control signal / reference signal processor 240 can receive a message including such a sleep execution condition.

[0079] The control signal and reference signal processor 240 may receive a lower layer message indicating a transition of the cell (gNB 100) to a dormant state in accordance with the NES. For example, the control signal and reference signal processor 240 may receive Layer 1 signaling (which may include DCI) or MAC-CE (Control Element) indicating that the source cell (which may include the target cell) will transition to the dormant state.

[0080] Furthermore, the control signal and reference signal processing unit 240 may receive a cell switch command including information indicating the transition to the dormant state. Specifically, the control signal and reference signal processing unit 240 may receive a cell switch command including an NES mode activation trigger from the gNB 100. In this case, the control signal and reference signal processing unit 240 may report to the gNB 100 in advance by L1 measurement reporting that a trigger condition (which may be interpreted as an event) for L1 measurement according to the NES has been satisfied.

[0081] The control signal and reference signal processor 240 can receive an RRC Reconfiguration including the configuration of a candidate cell (which may include a cell targeted for NES). In this case, considering that the cell targeted for NES is included, the information elements (IEs) constituting the RRC Reconfiguration may include an information element (additional information element) indicating whether the candidate cell is in a dormant state, separate from the information element indicating the candidate cell configuration (Candidate target cell config). The control signal and reference signal processor 240 may receive an RRC Reconfiguration including an additional information element (NES cell or Non-NES cell) indicating whether the candidate cell is in a dormant state.

[0082] The control signal and reference signal processor 240 may receive a request for transmitting terminal information (UEInformationRequest) from the network. Furthermore, the control signal and reference signal processor 240 may transmit terminal information (UEInformationResponse) including information about the cell to the network based on the state of the radio link and handover in a cell in a dormant state according to the NES (which may also be referred to as an NES cell). In this embodiment, the control signal and reference signal processor 240 may constitute a transmitter.

[0083] Specifically, the control signal / reference signal processing unit 240 may send a UEInformationResponse to the gNB 100 indicating the state of the NES cell when a radio link failure (RLF) or handover failure (HOF) occurs.

[0084] More specifically, when a radio link failure (RLF) occurs, the transmitter may transmit a UEInformationResponse including at least one of an indication indicating that the cell is in a dormant state, a type of the dormant state, cell identification information, a discontinuous transmission / discontinuous reception (DTX / DRX) format of the cell, location information of the terminal, and information on the time when the failure occurred. Note that the time when the failure occurred may be the time when the UE 200 detected the RLF, or may include the duration of the RLF, the time when the RLF was recovered, etc.

[0085] Furthermore, if the handover fails (HOF), the control signal / reference signal processing unit 240 may transmit a UEInformationResponse that includes at least any of the identification information of the source cell from which the handover originates, the identification information of the target cell to which the handover is to be performed, the reception quality (RSRP, RSRQ, SINR) of the source cell, the reception quality of the target cell, an indication that the source cell is in a dormant state, an indication that the target cell is in a dormant state, an indication that the candidate cell to which the handover is to be performed is in a dormant state, the format of discontinuous transmission / discontinuous reception (DTX / DRX) of the source cell, the format of discontinuous transmission / discontinuous reception of the target cell, location information of the UE 200, and information on the time when the failure occurred.

[0086] When transmitting such a UEInformationResponse, the control signal / reference signal processor 240 may include at least one of an offset and a hysteresis parameter for measurement associated with the dormant state. That is, the control signal / reference signal processor 240 may transmit a UEInformationResponse including an offset and a hysteresis parameter applied at the time of NES as the offset (O) and the hysteresis parameter (Hys) applied to the above-mentioned Measurement reporting event.

[0087] The network can configure measurement reporting to cause the UE to report measurement results for each SS / PBCH block. The network may configure measurement reporting to cause the UE to report measurement results for each SS / PBCH block(s), or may configure measurement reporting to cause the UE to report measurement results for each cell based on the SS / PBCH block(s). The network may configure measurement reporting to cause the UE to report measurement results for each CSI-RS resource, or may configure measurement reporting to cause the UE to report measurement results for each cell based on the CSI-RS resource.

[0088] Furthermore, control signal / reference signal processing unit 240 may transmit UEInformationResponse including at least one of identification information of a cell related to cell transition of UE200 by CHO or LTM and an indication that the related cell is in a dormant state. Note that LTM may include LTM fast failure recovery. LTM fast failure recovery is a mechanism in which, in the event of an LTM failure, UE200 performs cell selection and, if the selected cell is an LTM candidate cell, directly applies the configuration of the candidate cell without transmitting an RRCReestablishmentRequest to gNB100.

[0089] Furthermore, when transmitting such a UEInformationResponse, the control signal / reference signal processing unit 240 may transmit a UEInformationResponse that includes the time from when the cell receives an instruction to transition to a dormant state (NES mode activation trigger) to when the handover starts, is completed, or fails.

[0090] Specifically, the control signal / reference signal processing unit 240 may transmit a UEInformationResponse that includes the time required from receiving the NES mode activation trigger from the source cell side until the handover is successful or unsuccessful, and the time required from receiving the NES mode activation trigger from the source cell side until the handover is executed (regardless of whether it is successful or unsuccessful).

[0091] The control signal and reference signal processor 240 may transmit to the network capability information of the UE 200. For example, the control signal and reference signal processor 240 may transmit to the gNB 100 UE Capability Information regarding trigger conditions for measurement reports, support for NES, and the like.

[0092] Furthermore, the control signal and reference signal processing unit 240 may receive lower layer signaling instructing the secondary cell to transition to a dormant state (NES mode) in order to reduce energy consumption. In this embodiment, the control signal and reference signal processing unit 240 may constitute a receiving unit that receives lower layer signaling.

[0093] The encoding / decoding unit 250 performs data division / concatenation and channel coding / decoding for each predetermined communication destination (gNB 100 or another gNB).

[0094] Specifically, the encoding / decoding unit 250 divides the data output from the data transmitting / receiving unit 260 into pieces of a predetermined size, performs channel coding on the divided data, decodes the data output from the modem unit 230, and concatenates the decoded data.

[0095] The data transmitter / receiver 260 transmits and receives Protocol Data Units (PDUs) and Service Data Units (SDUs). Specifically, the data transmitter / receiver 260 assembles and disassembles PDUs / SDUs in multiple layers (such as a Medium Access Control layer (MAC), a Radio Link Control layer (RLC), and a Packet Data Convergence Protocol layer (PDCP)). The data transmitter / receiver 260 also performs data error correction and retransmission control based on Hybrid Automatic Repeat Request (Hybrid ARQ).

[0096] The control unit 270 controls each functional block constituting the UE 200. In particular, in this embodiment, the control unit 270 executes control related to CHO, LTM, and NES.

[0097] Specifically, the control unit 270 controls the cell transition (handover) of the UE 200 according to LTM (lower layer mobility control). Also, the control unit 270 controls the cell transition (handover) according to conditional handover (CHO). In both LTM and CHO, an execution condition may be applied, which is used to determine whether or not to execute the cell transition (handover).

[0098] As described above, LTM may be interpreted as cell transition due to processing in the lower layer (L1 / L2), and CHO may be interpreted as cell transition due to processing in the upper layer (L3).

[0099] The control unit 270 may execute cell transition when the source cell or the candidate cell satisfies an execution condition (execution condition for dormancy) that is applied when transitioning to a dormant state according to the NES. The execution condition may be for LTM or for CHO. As described above, a unique measurement offset or hysteresis parameter different from that of the normal LTM (CHO) may be applied to the execution condition.

[0100] That is, the control unit 270 may execute a cell transition when at least one of a specific measurement offset and a specific measurement hysteresis parameter associated with the cell's dormant state according to the NES (which may include the DTX / DRX state, as described above) satisfies the applied dormant execution condition.

[0101] The control unit 270 may execute a cell transition (handover) according to the LTM (or CHO) when the execution condition for dormancy received by the control signal / reference signal processing unit 240 is satisfied. Note that the execution condition for dormancy does not necessarily need to be transmitted from the network, and may be pre-configured in the UE 200.

[0102] Furthermore, when the control signal / reference signal processor 240 receives a lower layer message indicating transition to a dormant state in accordance with the NES and the dormant execution condition is satisfied, the controller 270 may execute a cell transition. The lower layer message may be Layer 1 signaling or MAC-CE, as described above.

[0103] Alternatively, the control unit 270 may execute the cell change based on a cell switch command. Specifically, the control unit 270 may execute the cell change based on a Cell switch command including an NES mode activation trigger.

[0104] The control unit 270 may refer to an additional information element (NES cell or Non-NES cell) included in the candidate cell configuration (Candidate target cell config) to determine whether the cell is in a dormant state according to the NES. That is, the control unit 270 may refer to the additional information element to determine whether the candidate cell is in a dormant state. By referring to only the additional information element, the control unit 270 can quickly determine whether the candidate cell is in a dormant state without referring to (decoding) the Candidate target cell config.

[0105] Furthermore, when the control signal / reference signal processing unit 240 receives lower layer signaling indicating that the gNB 100 (or a cell) transitions to the NES mode, the control unit 270 may delete or deactivate the secondary cell. When the control unit 270 receives the signaling, the control unit 270 may start monitoring the execution conditions for deleting or changing the secondary cell.

[0106] Furthermore, the gNB 100 may have the following functions: Specifically, the gNB 100 may have a control signal / reference signal processing unit 240 (receiving unit) that receives a measurement report from the UE 200, and a control unit 270 that configures the UE 200 with multiple secondary cell candidates that the UE 200 can autonomously select based on the measurement report.

[0107] The control unit 270 of the gNB100 may set execution conditions for adding, deleting, or modifying secondary cells.

[0108] In addition, the gNB100 may include a radio signal transceiver unit 210 (communication unit) that performs radio communication with the UE200 via a secondary cell, and a control unit 270 that sets a priority for the secondary cell when setting a candidate secondary cell.

[0109] The control unit 270 of the gNB100 may set the priority based on at least one of the energy consumption cost in the secondary cell, the required communication quality, and the capabilities of the UE200.

[0110] In addition, the control unit 270 of the gNB 100 may set a priority for each secondary cell candidate when at least one of conditional handover (CHO), conditional cell change (CPC), and lower layer mobility control (LTM) is applied.

[0111] In addition, the control unit 270 of the gNB 100 may set the priority based on at least one of the congestion level of the secondary cell and whether or not it is in a dormant state.

[0112] (3) Operation of the Wireless Communication System Next, a description will be given of the operation of the wireless communication system 10. Specifically, a description will be given of an example of operation relating to addition, modification, or deletion of a secondary cell (SCell) when NES is applied.

[0113] (3.1) Operation Example 1 Figure 4 shows an example of the configuration of a primary cell and a secondary cell. In the existing SCell change, SCell addition and SCell release are transmitted by RRC signaling from the gNB to the UE based on a measurement report from the UE. In other words, the UE cannot autonomously change the SCell.

[0114] 5 shows an example of an SCell configuration sequence according to operation example 1. In this operation example, the gNB may configure multiple candidate SCell(s) in the UE in advance based on a measurement report from the UE.

[0115] The gNB may configure an execution condition for the UE to autonomously delete or deactivate the SCell. The execution condition may be that the quality of the SCell falls below a predetermined threshold.

[0116] The gNB may configure an execution condition for autonomously adding or activating an SCell in a UE. The execution condition may be that the quality of the SCell is above a predetermined threshold.

[0117] The gNB may configure an execution condition for changing or adding an SCell to the UE. The execution condition may be that the quality of a neighbor cell is higher than the quality of the SCell by an offset.

[0118] Furthermore, the UE may monitor the above-described execution condition, and when the execution condition is satisfied, may autonomously perform deactivation, activation, or change of the SCell.

[0119] The UE may maintain a candidate SCell list and execution conditions for further SCell deletion (deactivation), SCell addition (activation), and SCell modification.

[0120] If the UE receives RRC signaling from the gNB to change or modify the candidate SCell list, the UE can change or delete the listed candidate SCells.

[0121] According to this operation example, the gNB can configure multiple candidate SCell(s) in the UE in advance based on a measurement report from the UE, and can configure an execution condition for the UE to autonomously delete or deactivate the SCell. Therefore, even when NES is applied, the UE can autonomously add, change, or delete an appropriate SCell. This can realize appropriate cell change, etc., even when NES is introduced.

[0122] (3.2) Operation Example 2 When an SCell is an NES cell, it is desirable that a normal UE under the control of the cell transition to another normal SCell when the NES mode of the SCell is activated. However, in the existing 3GPP specifications, it is necessary to execute a procedure to delete the NES mode SCell and add another normal SCell by RRC signaling from the gNB. In other words, the UE cannot autonomously change the NES SCell to another normal SCell.

[0123] In addition, NES mode may mean that the cell transitions to a sleep state or cell DTX / DRX state, is changed to an SSB-less cell, or is changed to a cell that does not broadcast SIB (system information), thereby achieving energy reduction effects.

[0124] In addition, when a primary / secondary cell (PSCell) in dual connectivity is an NES cell, it is desirable that normal UEs under the cell change (transition) to another normal PSCell when the NES mode of the PSCell is activated. In this case, a conditional PSCell addition change (CPAC) can be performed, but a specific method that takes into account the NES cell has not yet been developed.

[0125] (3.2.1) Operation Example 2-1 When a UE receives L1 group signaling that transitions to the NES mode (for example, Cell DTX / DRX) in an SCell, the UE may autonomously delete (or deactivate) the SCell.

[0126] Fig. 6 shows an example of an SCell configuration sequence according to Operation Example 2. As shown in Fig. 6, when the UE receives L1 group signaling indicating transition to the NES mode (e.g., Cell DTX / DRX) in the SCell, the UE may start monitoring the execution condition of SCell delete (deactivation) or SCell change, similarly to Operation Example 1. When the execution condition is satisfied, the UE may execute SCell delete (deactivation) / SCell change.

[0127] When the UE receives L1 group signaling indicating transition to NES mode (e.g., Cell DTX / DRX) in the SCell, and when the execution conditions for SCell delete (deactivation) and SCell change are satisfied as in Operation Example 1, the UE may execute SCell delete (deactivation) / SCell change.

[0128] Other than the L1 group signaling for transitioning to the NES mode (for example, Cell DTX / DRX) in the SCell, MAC CE indicating NES mode activation or RRC signaling may be used.

[0129] (3.2.2) Operation Example 2-2 The execution condition of CPAC may include an NES-specific hysteresis, an NES-specific offset, or an NES-specific timeToTrigger. The NES-specific offset may be for each cell or for each measObject / frequency.

[0130] The execution condition of CPAC may refer to conditional events condEventA3, condEventA4, and condEventA5 (see 3GPP TS38.331).

[0131] For example, if the source PSCell is an NES cell, a low NES offset value may be set to make it easier to perform a PSCell change, or if the candidate target cell is an NES cell, a high NES offset value may be set to make it harder to perform a PSCell change than other normal candidate cells.

[0132] As the execution condition of the CPAC, a normal execution condition and an NES execution condition may be pre-configured by the RRC. The normal execution condition may be used as a default (when there is no particular instruction from the gNB).

[0133] Alternatively, the NES execution condition may be used as a default, or an instruction to switch from the normal execution condition to the NES execution condition may be transmitted to the UE from the source gNB / PSCell via L1 group signaling, L1 signaling, or MAC CE.

[0134] Upon receiving the instruction, the UE may apply the parameters of the NES execution condition (e.g., hysteresis, offset, and timeToTrigger for NES) and monitor the execution condition.

[0135] The UE may trigger CPAC when it receives L1 group signaling or MAC CE (e.g., including an NES mode activation trigger) from a source PSCell and an execution condition (e.g., neighbor cell's quality becomes better than serving cell's quality) is satisfied.

[0136] Furthermore, the UE may start monitoring the execution condition in response to receiving L1 group signaling or MAC CE from the source PSCell.

[0137] According to this operation example, the UE performs autonomous deletion of the SCell based on signaling from the network, etc. Therefore, even when NES is applied, the UE can autonomously perform appropriate addition, change, deletion, etc. of the SCell. This makes it possible to realize appropriate cell change, etc. even when NES is introduced.

[0138] (3.3) Operation Example 3 In the existing 3GPP specifications, when a UE autonomously adds or modifies an SCell, the UE determines whether or not to add or modify the SCell based only on the reception quality of the cell. In other words, the UE cannot autonomously add or modify the SCell while taking into account factors such as the congestion level of the SCell and the NES cell.

[0139] Furthermore, when performing CHO, CPAC, or LTM, the UE monitors only the quality of the candidate target cell to determine whether to perform cell transfer, and cannot perform CHO, CPAC, or LTM taking into account factors such as the congestion level of the candidate target cell and the NES cell.

[0140] (3.3.1) Operation Example 3-1 When configuring candidate SCells, the gNB may apply weighting or priority (weight / priority) to each SCell. The weight / priority may take into consideration the cell congestion level, the NES cell, the URLLC (Ultra-Reliable and Low Latency Communications) function, the redCap (Reduced UE Capability) function, etc.

[0141] For example, if SCell#1 (see FIG. 4) is congested, the weight / priority may be set to "1." If SCell#2 is less congested, the weight / priority may be set to "2."

[0142] Here, if both SCell#1 and SCell#2 satisfy the quality condition, SCell#2 may be preferentially accessed. Alternatively, the congestion level for each SCell may be directly indicated. For example, SCell#1: 70, SCell#2: 30, etc. may be indicated (100 may mean full capacity). The congestion level may be a future congestion level predicted by an artificial intelligence / machine learning model (AI / ML model).

[0143] Furthermore, if the UE is a normal UE and SCell#1 is an NES cell, the weight / priority may be set to "1". If SCell#2 is a normal cell, the weight / priority may be set to "2". In this case, if both SCell#1 and SCell#2 satisfy the quality conditions, access to SCell#2 may be prioritized. Furthermore, it may be directly indicated that the SCell is an NES cell or a non-NES cell. The NES cell indication may be a predicted value that the cell will transition to the NES mode at a specific time in the future predicted by AI / ML.

[0144] As with the above-described NES cell, weight / priority may be determined depending on whether the SCell supports URLLC, RedCap, etc., according to the UE capability. Specifically, if the UE has URLLC capability and SCell#1 does not support the URLLC function, weight / priority may be set to "1." If SCell#2 supports the URLLC function, weight / priority may be set to "2." In this case, if SCell#1 and SCell#2 simultaneously satisfy the quality conditions, SCell#2 may be preferentially accessed.

[0145] The UE may preferentially access a cell with a higher weight / priority (same below).

[0146] (3.3.2) Operation Example 3-2 In the case of CHO, CPC, or LTM, when Gnb configures candidate target cells, weight / priority may be assigned to each candidate target cell.

[0147] The weight / priority may take into consideration factors such as congestion level or NES cell factors.

[0148] For example, if candidate target cell #1 is congested, weight / priority may be set to "1." If candidate target cell #2 is less congested, weight / priority may be set to "2."

[0149] In this case, if the quality conditions of both candidate target cell #1 and candidate target cell #2 are satisfied, candidate target cell #2 may be preferentially accessed. Alternatively, the congestion level may be directly indicated for each candidate target cell. For example, candidate target cell #1 may be indicated as 70, candidate target cell #2 as 30, etc. (100 may indicate full capacity). The congestion level may be a future congestion level predicted by AI / ML. The UE may preferentially access an empty cell.

[0150] Furthermore, if candidate target cell #1 is an NES cell, the weight / priority may be set to "1." If candidate target cell #2 is a normal cell, the weight / priority may be set to "2."

[0151] In this case, if both candidate target cell #1 and candidate target cell #2 satisfy the quality condition, the UE may preferentially access candidate target cell #2. Alternatively, the SCell may be directly indicated as an NES cell or a non-NES cell. The NES cell indication may be a predicted value that the cell will transition to the NES mode at a specific time in the future predicted by AI / ML. The UE may preferentially access a non-NES cell.

[0152] As with the above-described NES cell, the weight / priority may be determined depending on whether the SCell supports URLLC, RedCap, etc., according to the UE capability. Specifically, if the UE has URLLC capability and candidate target cell #1 does not support the URLLC function, the weight / priority may be set to "1." If candidate target cell #2 supports the URLLC function, the weight / priority may be set to "2." In this case, if candidate target cell #1 and candidate target cell #2 simultaneously satisfy the quality conditions, candidate target cell #2 may be preferentially accessed.

[0153] According to this operation example, weighting or priority (weight / priority) is applied to the SCell or candidate target cell based on factors such as congestion level or NES cell. Therefore, even when NES is applied, the UE can autonomously perform appropriate addition, change, or deletion of the SCell. This makes it possible to realize appropriate cell change, etc., even when NES is introduced.

[0154] (4) Other Embodiments The contents of the present proposal have been explained above using examples, but it will be obvious to those skilled in the art that the present proposal is not limited to these descriptions and that various modifications and improvements are possible.

[0155] Although the embodiments have been described above, it will be obvious to those skilled in the art that the present invention is not limited to the description of the embodiments and that various modifications and improvements are possible.

[0156] For example, in the above-described embodiment, the name NES was used, but the technology for reducing energy consumption of a network as described above may be referred to by another name having a similar meaning.

[0157] Also, in the above description, configure, activate, update, indicate, enable, specify, and select may be interchangeable. Similarly, link, associate, correspond, and map may be interchangeable, and allocate, assign, monitor, and map may be interchangeable.

[0158] Furthermore, specific, dedicated, UE-specific, and UE-dedicated may be interchangeable. Similarly, common, shared, group-common, UE-common, and UE-shared may be interchangeable.

[0159] In this disclosure, terms such as "precoding," "precoder," "weight (precoding weight)," "Quasi-Co-Location (QCL)," "Transmission Configuration Indication state (TCI state)," "spatial relation," "spatial domain filter," "transmit power," "phase rotation," "antenna port," "antenna port group," "layer," "number of layers," "rank," "resource," "resource set," "resource group," "beam," "beam width," "beam angle," "antenna," "antenna element," "panel," etc. may be used interchangeably.

[0160] The block diagram ( FIG. 3 ) used to explain the above-described embodiment shows functional blocks. These functional blocks (components) are realized by any combination of hardware and / or software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are connected directly or indirectly (e.g., via wire, wireless, etc.) and these multiple devices. The functional block may be realized by combining the single device or multiple devices with software.

[0161] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how each is implemented.

[0162] Furthermore, the above-described gNB100 and UE200 (the devices) may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 7 is a diagram showing an example of the hardware configuration of the devices. As shown in Figure 7, the devices may be configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0163] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the apparatus may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0164] Each functional block of the device (see FIG. 3) is realized by any hardware element of the computer device or a combination of the hardware elements.

[0165] In addition, each function of the device is realized by loading specified software (programs) onto hardware such as processor 1001 and memory 1002, causing processor 1001 to perform calculations, control communication via communication device 1004, and control at least one of reading and writing data in memory 1002 and storage 1003.

[0166] The processor 1001 controls the entire computer by running, for example, an operating system, and may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control unit, an arithmetic unit, and registers.

[0167] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. Furthermore, the various processes described above may be executed by a single processor 1001, or may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0168] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 may store a program (program code), a software module, etc., capable of executing a method according to an embodiment of the present disclosure.

[0169] Storage 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned recording medium may be, for example, a database, a server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0170] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0171] The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize, for example, at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD).

[0172] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0173] Furthermore, each device such as the processor 1001 and the memory 1002 is connected to a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0174] Furthermore, the device may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0175] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0176] Each aspect / embodiment described in the present disclosure may be applied to at least one of a system using Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, a 4th generation mobile communication system (4G), a 5th generation mobile communication system (5G), a 6th generation mobile communication system (6G), an xth generation mobile communication system (xG) (where x is, for example, an integer or a decimal), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable system, and a next-generation system extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G) may also be applied.

[0177] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0178] In the present disclosure, a specific operation described as being performed by a base station may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal may be performed by at least one of the base station and another network node other than the base station (e.g., MME or S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, a combination of multiple other network nodes (e.g., MME and S-GW) may also be used.

[0179] Information, signals (information, etc.) may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input and output via multiple network nodes.

[0180] The input and output information may be stored in a specific location (for example, a memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added. The output information may be deleted. The input information may be transmitted to another device.

[0181] The determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0182] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0183] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0184] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0185] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0186] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0187] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0188] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0189] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0190] In this disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0191] A base station can accommodate one or more (e.g., three) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0192] The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0193] In the present disclosure, the base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control or operate based on the information.

[0194] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0195] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0196] At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, etc. The mobile object refers to a movable object, and may move at any speed. Naturally, this also includes cases where the mobile object is stationary. Examples of the mobile object include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcars, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and objects mounted thereon. The mobile object may also be a mobile object that moves autonomously based on an operational command. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may be a device that does not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0197] Furthermore, a base station in the present disclosure may be read as a mobile station (user terminal, the same applies hereinafter). For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a mobile station is replaced with communication between multiple mobile stations (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the mobile station may be configured to have the functions of a base station. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel (or sidelink).

[0198] Similarly, a mobile station in the present disclosure may be interpreted as a base station, in which case the base station may have the functions of a mobile station.

[0199] A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0200] Numerology may be communication parameters that apply to the transmission and / or reception of a signal or channel, such as subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0201] A slot may consist of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol, etc.) A slot may be a numerology-based time unit.

[0202] A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0203] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0204] For example, one subframe may be referred to as a transmission time interval (TTI), multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0205] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station schedules each user terminal to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) in TTI units. Note that the definition of TTI is not limited to this.

[0206] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0207] In addition, when one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling, and the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0208] A TTI having a time length of 1 ms may be referred to as a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be referred to as a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0209] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0210] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and may include one or more consecutive subcarriers in the frequency domain.

[0211] The number of subcarriers included in an RB may be the same regardless of the numerology, and may be, for example, 12. The number of subcarriers included in an RB may also be determined based on the numerology.

[0212] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI, each of which may consist of one or more resource blocks.

[0213] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0214] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0215] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0216] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0217] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0218] The above-described structures of the radio frame, subframe, slot, minislot, and symbol are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, and other configurations may be changed in various ways.

[0219] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0220] The reference signal may also be abbreviated as Reference Signal (RS) and may be called a pilot depending on the applicable standard.

[0221] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0222] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0223] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way.

[0224] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0225] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0226] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0227] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0228] Fig. 8 shows an example of the configuration of a vehicle 2001. As shown in Fig. 8, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013.

[0229] The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor.

[0230] The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user.

[0231] The electronic control unit 2010 is composed of a microprocessor 2031, a memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals are input to the electronic control unit 2010 from various sensors 2021 to 2027 provided in the vehicle. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0232] The signals from the various sensors 2021 to 2028 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0233] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing (outputting) various types of information, such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 uses information acquired from external devices via the communication module 2013, etc., to provide various types of multimedia information and multimedia services to the occupants of the vehicle 1.

[0234] The information service unit 2012 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

[0235] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driver's driving burden, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS, etc.), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. The driving assistance system unit 2030 also transmits and receives various information via the communication module 2013 to realize driving assistance functions or autonomous driving functions.

[0236] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 1 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from a driving unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, a microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 2028, which are provided in the vehicle 2001.

[0237] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

[0238] The communication module 2013 may transmit at least one of signals from the above-mentioned various sensors 2021 to 2028 input to the electronic control unit 2010, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 2012 to an external device via wireless communication. The electronic control unit 2010, the various sensors 2021 to 2028, the information service unit 2012, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above-mentioned input.

[0239] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on an information service unit 2012 provided in the vehicle. The information service unit 2012 may also be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores the various information received from external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axles 2009, sensors 2021 to 2028, and the like provided in the vehicle 2001.

[0240] (Additional Note) The above disclosure may be expressed as follows: A first feature is a radio base station including: a receiver that receives a measurement report from a terminal; and a controller that configures, for the terminal, a plurality of secondary cell candidates that the terminal can autonomously select, based on the measurement report.

[0241] In a second feature based on the first feature, the control unit sets an execution condition for adding, deleting, or changing the secondary cell.

[0242] A third feature is a terminal that includes a receiving unit that receives lower layer signaling indicating that a secondary cell transitions to a dormant state due to a reduction in energy consumption, and a control unit that deletes or deactivates the secondary cell when the signaling is received.

[0243] A fourth feature based on the third feature is that, when the control unit receives the signaling, the control unit starts monitoring an execution condition for deleting or changing the secondary cell.

[0244] A fifth feature is a radio base station comprising: a communication unit that performs wireless communication with a terminal via a secondary cell; and a control unit that sets a priority for the secondary cell when setting a candidate for the secondary cell, wherein the control unit sets the priority based on at least one of the energy consumption cost in the secondary cell, the required communication quality, and the capability of the terminal.

[0245] A sixth feature is the fifth feature, wherein the control unit sets the priority for each of the secondary cell candidates when at least one of a conditional handover, a conditional cell change, and mobility control by a lower layer is applied.

[0246] A seventh feature based on the fifth or sixth feature is that the control unit sets the priority based on at least one of a congestion level of the secondary cell and whether or not the secondary cell is in a dormant state.

[0247] 10 Wireless communication system 20 NG-RAN 100 gNB 200 UE 210 Wireless signal transceiver 220 Amplifier 230 Modulation / demodulation unit 240 Control signal / reference signal processing unit 250 Encoding / decoding unit 260 Data transceiver 270 Control unit 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Left and right front wheels 2008 Left and right rear wheels 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 RPM sensor 2023 Air pressure sensor 2024 Vehicle speed sensor 2025 Acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object detection sensor 2029 Accelerator pedal sensor 2030 Driving assistance system section 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port

Claims

1. A radio base station comprising: a receiving unit that receives a measurement report from a terminal; and a control unit that sets, for the terminal, a plurality of secondary cell candidates that the terminal can autonomously select based on the measurement report.

2. The radio base station according to claim 1, wherein the control unit sets execution conditions for adding, deleting or modifying the secondary cell.

3. A terminal comprising: a receiving unit that receives lower layer signaling indicating that a secondary cell transitions to a dormant state in order to reduce energy consumption; and a control unit that deletes or deactivates the secondary cell when the signaling is received.

4. The terminal according to claim 3, wherein the control unit starts monitoring execution conditions for deleting or changing the secondary cell when the signaling is received.