terminal

Abstract

To provide a terminal that appropriately executes processing related to conditional reconfiguration of a terminal (UE) mounted on an unmanned aerial vehicle (UAV).SOLUTION: In a wireless communication system 10 including radio base stations 100A to 100D having cells C1 to C4 respectively, UE 200 includes a control unit that selects a target cell from two or more candidate cells in conditional reconfiguration, and a transmission unit that transmits a message for connecting to the target cell in the conditional reconfiguration. The control unit selects the target cell based on a condition related to the number of beams of each of the two or more candidate cells. The condition related to the number of beams includes at least one of a condition that the number of beams satisfying a specific quality is the maximum and a condition that the number of beams satisfying the specific quality exceeds a specific number.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a base station and a terminal that perform processing related to conditional reconfiguration of a terminal mounted on an unmanned aerial vehicle or the like. [Background technology]

[0002] The 3rd Generation Partnership Project (3GPP) has developed 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] 3GPP Release 15 is considering services and use cases using small unmanned aerial vehicles (UAVs), such as drones equipped with wireless communication modules similar to UEs (see Non-Patent Document 1).

[0004] 3GPP Release 16 introduces conditional reconfiguration, which executes connection to a target cell without sending a re-establishment request message to the target cell. Conditional reconfiguration may include Conditional Handover (CHO), Conditional PSCell (Primary Secondary Cell) Change (CPC), and Conditional PSCell Addition. In conditional reconfiguration, the UE autonomously connects to a cell that satisfies the execution condition (CHO execution condition). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] 3GPP TR 36.777 V15.0.0, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Study on Enhanced LTE Support for Aerial Vehicles (Release 15), 3GPP, December 2017 Summary of the Invention

[0006] Unlike ordinary UEs, UEs mounted on unmanned aerial vehicles (UAVs) fly above base stations, making them less susceptible to obstructions such as buildings and offering good visibility of the propagation environment.

[0007] Under these circumstances, the inventors, after thorough investigation, have found that, since it is necessary to reserve radio resources of the target cell in conditional reconfiguration, it may be impossible to effectively utilize the radio resources of the target cell. Furthermore, the inventors, after thorough investigation, have found that, since the outlook for the propagation environment is good, it is assumed that two or more candidate cells satisfy the execution conditions, and therefore connection to an appropriate cell may not be realized.

[0008] As described above, the inventors have found that there is room for various improvements in the conditional reconfiguration of UEs mounted on UAVs.

[0009] Therefore, the present disclosure has been made in consideration of such circumstances, and aims to provide a base station and a terminal that can appropriately perform processing related to conditional reconfiguration of a UE mounted on a UAV.

[0010] One aspect of the disclosure is a base station comprising a transmitter that transmits a message regarding conditional reconfiguration of a terminal to a neighboring cell based on a flight path of the terminal.

[0011] One aspect of the disclosure is a base station comprising: a receiving unit that receives a message regarding conditional reconfiguration of a terminal from a neighboring cell; and a control unit that releases radio resources related to the conditional reconfiguration when information elements included in the message satisfy specific conditions, wherein the information elements include at least one of an information element for identifying a flight path of the terminal and an information element for identifying reachability to the base station.

[0012] One aspect of the disclosure is a terminal comprising: a control unit that selects a target cell from two or more candidate cells in a conditional reconfiguration; and a transmission unit that transmits a message to connect to the target cell in the conditional reconfiguration, wherein the control unit selects the target cell based on a condition regarding the number of beams of each of the two or more candidate cells. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing the overall schematic configuration of a wireless communication system 10. As shown in FIG. [Figure 2] FIG. 2 is a diagram showing frequency ranges used in the wireless communication system 10. As shown in FIG. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of a radio frame, a subframe, and a slot used in the radio communication system 10. As shown in FIG. [Figure 4] FIG. 4 is a functional block diagram of the UE 200. [Figure 5] Figure 5 is a functional block diagram of gNB100. [Figure 6] FIG. 6 is a diagram illustrating an example of the operation of gNB100. [Figure 7] FIG. 7 is a diagram illustrating an example of the operation of gNB100. [Figure 8] FIG. 8 is a diagram illustrating an example of the operation of the UE 200. In FIG. [Figure 9] FIG. 9 is a diagram showing an example of the hardware configuration of gNB100 and UE200. DETAILED DESCRIPTION OF THE INVENTION

[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] [Embodiment] (1) Overall configuration of the wireless communication system 1 is a schematic diagram of an overall configuration of a wireless communication system 10 according to an 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 (hereinafter, UE 200).

[0016] The wireless communication system 10 may be a wireless communication system conforming to a system called Beyond 5G, 5G Evolution, or 6G.

[0017] The NG-RAN 20 includes radio base station 100A (hereinafter, gNB100A) to radio base station 100D (hereinafter, gNB100D). The gNBs 100A to 100D have cells C1 to C4, respectively. Note that the specific configuration of the radio communication system 10, including the number of gNBs and UEs, is not limited to the example shown in FIG. 1.

[0018] The NG-RAN 20 actually includes a plurality of NG-RAN nodes, specifically, gNBs (or ng-eNBs), and is connected to a 5G-compliant core network (5GC, not shown). The NG-RAN 20 and the 5GC may be simply referred to as a "network."

[0019] The gNB100A to gNB100D are radio base stations conforming to 5G, and perform 5G radio communication with the UE 200. The gNB100A to gNB100D and the UE 200 are capable of supporting Massive MIMO (Multiple-Input Multiple-Output), which generates a more directional beam BM 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 simultaneously communicates on two or more transport blocks between the UE and each of two NG-RAN nodes.

[0020] The UE 200 may be a UE mounted on a small unmanned aerial vehicle (UAV). The UE 200 mounted on a UAV or a UAV may be referred to as an NR drone. The UE 200 may also be referred to as a normal UE, a vehicle UE, an IAB (Integrated Access and Backhaul) UE (including an airborne IAB UE), a HAPS (High Altitude Platform Station) UE, an NTN (Non Terrestrial Network) UE, or the like.

[0021] The wireless communication system 10 also supports a plurality of frequency ranges (FR).

[0022] 2, the wireless communication system 10 supports FR1 and FR2. The frequency bands of each FR are as follows:

[0023] FR1: 410 MHz to 7.125 GHz FR2: 24.25 GHz~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 is a higher frequency than FR1, and may use an SCS of 60 or 120 kHz (including 240 kHz) and a bandwidth (BW) of 50 to 400 MHz.

[0024] 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.

[0025] Furthermore, the wireless communication system 10 also supports frequency bands higher than the FR2 frequency band. Specifically, the wireless communication system 10 supports frequency bands above 52.6 GHz up to 71 GHz or 114.25 GHz. For convenience, such high frequency bands may be referred to as "FR2x."

[0026] To solve the problem of increased phase noise in high frequency bands, 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.

[0027] FIG. 3 shows an example of the configuration of a radio frame, a subframe, and a slot used in the radio communication system 10. In FIG.

[0028] As shown in Figure 3, one slot consists of 14 symbols, and the larger (wider) the SCS, the shorter the symbol period (and slot period). The SCS is not limited to the interval (frequency) shown in Figure 3. For example, 480 kHz, 960 kHz, etc. may be used.

[0029] Also, the number of symbols constituting one slot does not necessarily have to be 14 (for example, 28 or 56 symbols). Furthermore, the number of slots per subframe may differ depending on the SCS.

[0030] The time direction (t) shown in Fig. 3 may be called a time domain, a symbol period, or a symbol time, etc. The frequency direction may be called a frequency domain, a resource block, a subcarrier, a bandwidth part (BWP), etc.

[0031] DMRS is a type of reference signal and is prepared for various channels. Here, unless otherwise specified, it may refer to a downlink data channel, specifically, a DMRS for a PDSCH (Physical Downlink Shared Channel). However, a DMRS for an uplink data channel, specifically, a PUSCH (Physical Uplink Shared Channel), may be interpreted as being the same as a DMRS for a PDSCH.

[0032] The DMRS may be used for channel estimation at the device, for example, as part of coherent demodulation at the UE 200. The DMRS may only be present in resource blocks (RBs) used for PDSCH transmission.

[0033] A DMRS may have multiple mapping types. Specifically, a DMRS has mapping type A and mapping type B. In mapping type A, the first DMRS is placed in the second or third symbol of a slot. In mapping type A, the DMRS may be mapped based on the slot boundary, regardless of where in the slot actual data transmission starts. The reason why the first DMRS is placed in the second or third symbol of a slot may be interpreted as being to place the first DMRS after a control resource set (CORESET).

[0034] In mapping type B, the first DMRS may be placed in the first symbol of the data allocation, i.e., the position of the DMRS may be given relative to where the data is placed, rather than relative to the slot boundary.

[0035] Furthermore, DMRS may have multiple types. Specifically, DMRS has Type 1 and Type 2. Type 1 and Type 2 differ in frequency domain mapping and the maximum number of orthogonal reference signals. Type 1 is a single-symbol DMRS that can output up to four orthogonal signals, while Type 2 is a double-symbol DMRS that can output up to eight orthogonal signals.

[0036] The wireless communication system 10 can support coverage enhancement (CE) that expands the coverage of a cell (or a physical channel) formed by the gNB 100. In coverage enhancement, a mechanism for increasing the success rate of reception of various physical channels may be provided.

[0037] For example, gNB100 can support repeated transmission of PDSCH (Physical Downlink Shared Channel), and UE200 can support repeated transmission of PUSCH (Physical Uplink Shared Channel).

[0038] A slot configuration pattern of time division duplex (TDD) may be set in the wireless communication system 10. For example, DDDSU (D: downlink (DL) symbol, S: DL / uplink (UL) or guard symbol, U: UL symbol) may be specified (see 3GPP TS38.101-4).

[0039] "D" indicates a slot containing all DL symbols, "S" indicates a slot containing a mixture of DL, UL, and guard symbols (G), and "U" indicates a slot containing all UL symbols.

[0040] Furthermore, in the wireless communication system 10, a demodulation reference signal (DMRS) can be used for each slot to perform channel estimation of the PUSCH (or PUCCH (Physical Uplink Control Channel)), and further, a DMRS allocated to each of multiple slots can be used to perform channel estimation of the PUSCH (or PUCCH). Such channel estimation may be called joint channel estimation, or may be called by another name such as cross-slot channel estimation.

[0041] UE200 can transmit DMRS allocated to (spanning) multiple slots so that gNB100 can perform joint channel estimation using DMRS.

[0042] Furthermore, in the wireless communication system 10, for coverage extension, TB processing over multi-slot PUSCH (TBoMS) may be applied, which processes a transport block (TB) via a PUSCH allocated to multiple slots.

[0043] In TBoMS, the number of allocated symbols may be the same in each slot, as in Time Domain Resource Allocation (TDRA) with PUSCH Repetition type A, or the number of allocated symbols may be different in each slot, as in TDRA with PUSCH Repetition type B.

[0044] The TDRA may be interpreted as a resource allocation in the time domain of the PUSCH as specified in 3GPP TS38.214. The TDRA of the PUSCH may be interpreted as being specified by an information element (IE) of the radio resource control layer (RRC), specifically, PDSCH-Config or PDSCH-ConfigCommon.

[0045] TDRA may also be interpreted as a time domain resource allocation for PUSCH specified by Downlink Control Information (DCI).

[0046] (2) Functional block configuration of wireless communication system Next, the functional block configuration of the wireless communication system 10 will be described.

[0047] First, the functional block configuration of the UE 200 will be described.

[0048] Fig. 4 is a functional block diagram of UE 200. As shown in Fig. 4, UE 200 includes radio signal transmitting / receiving unit 210, amplifier unit 220, modem unit 230, control signal / reference signal processing unit 240, encoding / decoding unit 250, data transmitting / receiving unit 260, and control unit 270.

[0049] The radio signal transmitting / receiving unit 210 transmits and receives radio signals conforming to NR. The radio signal transmitting / receiving unit 210 supports Massive MIMO, CA that uses a bundle of multiple CCs, and DC that simultaneously communicates between a UE and two NG-RAN nodes.

[0050] Here, the radio signal transceiver 210 may transmit an uplink channel (hereinafter referred to as an UL channel). In an embodiment, the radio signal transceiver 210 may constitute a transmitter.

[0051] Specifically, the radio signal transceiver 210 may transmit a PUSCH to the network (gNB 100). The radio signal transceiver 210 may support repeated transmission of the PUSCH. The UL channel may include a physical uplink shared channel (PUSCH) and a physical uplink control channel (PUCCH). The shared channel may be referred to as a data channel.

[0052] A plurality of types of repeated transmission of the PUSCH may be defined. Specifically, Repetition type A and Repetition type B may be defined. Repetition type A may be interpreted as a form in which the PUSCH allocated within a slot is repeatedly transmitted. In other words, the PUSCH is 14 symbols or less and is not likely to be allocated across multiple slots (adjacent slots).

[0053] On the other hand, Repetition type B may be interpreted as repeated transmission of a PUSCH in which a PUSCH of 15 or more symbols may be allocated. In an embodiment, such a PUSCH may be allowed to be allocated across a specific period including two or more slots.

[0054] The specific period including two or more slots may be interpreted as a period related to PUSCH (or PUCCH) repetition. For example, the specific period may be indicated by the number of repetitions, or may be a time period during which a specified number of repetitions are performed. In an embodiment, the specific period may be interpreted as a period during which joint channel estimation is applied. During the specific period, the UE 200 may not be able to receive a downlink channel (DL channel).

[0055] Alternatively, the radio signal transmitting and receiving unit 210 may repeatedly transmit the UL channel a specific number of times. Specifically, the radio signal transmitting and receiving unit 210 may repeatedly transmit the PUSCH (or PUCCH) a plurality of times.

[0056] The specific period and / or the specific number of times may be instructed by signaling from the network (which may be a higher layer of RRC or a lower layer such as DCI, the same applies below), or may be preset in UE200.

[0057] 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.

[0058] The modem unit 230 performs data modulation / demodulation, transmission power setting, resource block allocation, etc. for each predetermined communication destination (gNB 100 or another gNB). 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).

[0059] The control signal / reference signal processor 240 performs 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 .

[0060] Specifically, the control signal / reference signal processor 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. The control signal / reference signal processor 240 also transmits various control signals to the gNB 100 via a predetermined control channel.

[0061] The control signal / reference signal processor 240 performs processing using reference signals (RS) such as a Demodulation Reference Signal (DMRS) and a Phase Tracking Reference Signal (PTRS).

[0062] DMRS is a reference signal (pilot signal) known between the base station and the terminal for estimating the fading channel used for data demodulation. PTRS is a terminal-specific reference signal for estimating phase noise, which is an issue in high frequency bands.

[0063] In addition to the DMRS and PTRS, the reference signals may include a Channel State Information-Reference Signal (CSI-RS), a Sounding Reference Signal (SRS), and a Positioning Reference Signal (PRS) for position information.

[0064] The channels include control channels and data channels, such as a PDCCH (Physical Downlink Control Channel), a PUCCH (Physical Uplink Control Channel), a RACH (Random Access Channel), Downlink Control Information (DCI) including a Random Access Radio Network Temporary Identifier (RA-RNTI), and a Physical Broadcast Channel (PBCH).

[0065] Furthermore, the data channel includes a PDSCH (Physical Downlink Shared Channel) and a PUSCH (Physical Uplink Shared Channel). Data refers to data transmitted via the data channel. The data channel may be interpreted as a shared channel.

[0066] Here, the control signal and reference signal processor 240 may receive downlink control information (DCI). The DCI includes existing fields for storing DCI Formats, Carrier indicator (CI), BWP indicator, Frequency Domain Resource Allocation (FDRA), Time Domain Resource Allocation (TDRA), Modulation and Coding Scheme (MCS), HARQ Process Number (HPN), New Data Indicator (NDI), Redundancy Version (RV), etc.

[0067] The value stored in the DCI Format field is an information element that specifies the format of the DCI. The value stored in the CI field is an information element that specifies the CC to which the DCI applies. The value stored in the BWP indicator field is an information element that specifies the BWP to which the DCI applies. The BWP that can be specified by the BWP indicator is set by an information element (BandwidthPart-Config) included in the RRC message. The value stored in the FDRA field is an information element that specifies the frequency domain resource to which the DCI applies. The frequency domain resource is identified by the value stored in the FDRA field and an information element (RA Type) included in the RRC message. The value stored in the TDRA field is an information element that specifies the time domain resource to which the DCI applies. The time domain resource is identified by the value stored in the TDRA field and information elements (pdsch-TimeDomainAllocationList, pusch-TimeDomainAllocationList) included in the RRC message. The time domain resource may be identified by the value stored in the TDRA field and a default table. The value stored in the MCS field is an information element that specifies the MCS to which the DCI applies. The MCS is identified by the value stored in the MCS and an MCS table. The MCS table may be specified by an RRC message or may be determined by RNTI scrambling. The value stored in the HPN field is an information element that specifies the HARQ process to which the DCI is applied. The value stored in the NDI field is an information element for specifying whether the data to which the DCI is applied is initial transmission data. The value stored in the RV field is an information element that specifies the redundancy of the data to which the DCI is applied.

[0068] The encoding / decoding unit 250 performs data division / concatenation and channel coding / decoding for each predetermined communication destination (gNB100 or another gNB).

[0069] 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.

[0070] 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 HARQ (Hybrid Automatic Repeat Request).

[0071] The control unit 270 controls each functional block constituting the UE 200. In an embodiment, the control unit 270 may execute control related to conditional reconfiguration. The conditional reconfiguration is a procedure in which, under the premise that reconfiguration of two or more candidate cells is configured in the UE 200 in advance, the UE 200 monitors conditions related to each candidate cell and autonomously connects to a candidate cell for which the conditions are satisfied. The conditional reconfiguration may include conditional handover (CHO). The CHO is a procedure in which, under the premise that reconfiguration of two or more candidate cells (target cells) is configured in the UE 200 in advance, the UE 200 monitors execution conditions related to each candidate cell and autonomously connects to a candidate cell for which the execution conditions are satisfied. The UE 200 executes cell reselection when the CHO fails, and, if the cell selected in the cell reselection is a candidate cell, executes connection to the candidate cell without transmitting an RRC re-establishment request to the network. The conditional reconfiguration may include a Conditional PSCell Change (CPC) that realizes a change of a PSCell (Primary Secondary Cell) and a Conditional PSCell Addition that realizes an addition of a PSCell. The PSCell Change / Addition is a procedure in which, on the premise that the reconfiguration of a plurality of candidate cells (candidate secondary cells (PSCells)) is configured in the UE 200 in advance, the UE 200 monitors the change condition / addition condition for each candidate cell and autonomously connects to a candidate cell for which the change condition / addition condition is satisfied.

[0072] In the conditional resetting, when a candidate cell satisfies a condition (execution condition, change condition, or additional condition, the same applies below), the control unit 270 autonomously executes a procedure (random access procedure) for connecting to the candidate cell.

[0073] For example, the execution conditions for CHO may include CondEventA3 and CondEventA5.

[0074] CondEvent A3 is an event where the reception quality of the neighboring cell is better than the reception quality of the serving cell by an offset. For example, CondEvent A3 may be Mn + Ofn + Ocn - Hys > Mp + Ofp + Ocp + Off.

[0075] 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.

[0076] CondEvent A5 is an event in which the reception quality of the serving cell becomes worse than a threshold and the reception quality of the neighboring cell becomes better than a threshold, for example, CondEvent A5 may be Mp + Hys < Thresh1 and Mn + Ofn + Ocn - Hys > Thresh2.

[0077] Here, Mp is the reception quality of the SpCell (Special Cell), Hys is a hysteresis parameter, and Thresh1 is a threshold. Mn is the reception quality of the neighboring cell, Ofn is an offset specific to the measurement object, and Ocn is an offset specific to the cell. Hys is a hysteresis parameter, and Thresh2 is a threshold.

[0078] For example, the change condition / addition condition for the Conditional PSCell Change / Addition may include Event B1 and Event B2.

[0079] Event B1 may be an event in which the reception quality of the neighboring cell becomes better than a threshold, for example, Event B1 may be Mn + Ofn + Ocn - Hys > Thresh.

[0080] 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.

[0081] Event B2 is an event in which the reception quality of the PCell becomes worse than a threshold and the reception quality of a neighboring cell becomes better than a threshold. For example, Event B2 may be Mp + Hys < Thresh1 and Mn + Ofn + Ocn - Hys > Thresh2.

[0082] Here, Mp is the reception quality of the PCell, Hys is a hysteresis parameter, and Thresh1 is a threshold value. Mn is the reception quality of a neighboring cell, Ofn is an offset specific to the measurement object, and Ocn is an offset specific to the cell. Hys is a hysteresis parameter, and Thresh2 is a threshold value.

[0083] In this context, the control unit 270 may select a target cell from two or more candidate cells. The selection of the target cell may be performed when two or more candidate cells simultaneously satisfy a condition within a certain period of time. In such a case, the control unit 270 may select the target cell based on a condition regarding the number of beams of each of the two or more candidate cells.

[0084] The condition regarding the number of beams may include at least one of a condition that the number of beams satisfying a specific quality is the maximum and a condition that the number of beams satisfying the specific quality exceeds a specific number.

[0085] As the parameter defining the specific quality, an existing parameter (e.g., absThreshSS-BlocksConsolidation, absThreshCSI-RS-Consolidation, etc.) may be used. As the parameter defining the specific quality, a new parameter may be introduced. The parameter defining the specific number may be referred to as NumberOfGoodBeam. These parameters may be set by an RRC message.

[0086] Here, the specific quality may be set based on altitude information of UE200, or may be adjusted by UE200 based on the altitude information of UE200. For example, the higher the altitude of UE200, the higher the quality set as the specific quality or the specific quality may be adjusted to a higher quality. The specific number may be set based on altitude information of UE200, or may be adjusted by UE200 based on the altitude information of UE200. For example, the higher the altitude of UE200, the higher the number set as the specific number or the specific number may be adjusted to a higher number.

[0087] The condition regarding the number of beams may be incorporated into the above-mentioned conditions (CondEventA3, CondEventA5, EventB1, EventB2, etc.) For example, a new condition may be defined that incorporates a condition regarding the number of beams.

[0088] Control unit 270 controls control signal and reference signal processing unit 240 to transmit a message (RACH) for connecting to the target cell. In other words, control signal and reference signal processing unit 240 constitutes a transmission unit that transmits a message for connecting to the target cell in conditional reconfiguration.

[0089] Furthermore, the control unit 270 may measure the reception quality of neighboring cells when transmitting a measurement report to the network. For example, the control unit 270 measures the average of the reception qualities of beams related to the neighboring cells as the reception quality of the neighboring cells. In such a case, a minimum number of beams to be used for measuring the reception quality of the neighboring cells may be defined. The minimum number may be referred to as minimumNrofSS-BlocksToAverage. minimumNrofSS-BlocksToAverage may be set by an RRC message (e.g., MeasObjectNR).

[0090] Specifically, the control unit 270 may measure the reception quality of neighboring cells having the minimum number of beams that satisfy the specific quality or more, without measuring the reception quality of neighboring cells having less than the minimum number of beams that satisfy the specific quality.The control unit 270 may report the reception quality of neighboring cells having the minimum number of beams or more, without reporting the reception quality of neighboring cells having less than the minimum number of beams.

[0091] Secondly, we will explain the functional block configuration of gNB100.

[0092] Fig. 5 is a functional block diagram of the gNB 100. As shown in Fig. 5, the gNB 100 includes a receiving unit 110, a transmitting unit 120, and a control unit 130.

[0093] The receiving unit 110 receives various signals from the UE 200. The receiving unit 110 may receive the UL signal via an UL channel such as a PUCCH or a PUSCH. For example, when a cell of the gNB 100 functions as a candidate cell (or a target cell), the receiving unit 110 may receive a message related to conditional reconfiguration of the UE 200 from a neighboring cell. The message may be a message related to CHO (Handover Request) or a message related to Conditional PSCell Change / Addition (SN Modification Request / SN Addition Request).

[0094] In such a case, the message may include an information element for specifying the flight path of UE 200. The flight path of UE 200 may be specified by an information element (e.g., flightPathInfoReport) included in a message (e.g., UEInformationResponse) received from UE 200. The message may include an information element (e.g., Estimated Arrival Probability) for specifying reachability to a neighboring cell. The Estimated Arrival Probability may be an information element that is not based on the flight path of UE 200, or may be an information element based on the flight path of UE 200.

[0095] The transmitter 120 transmits various signals to the UE 200. The transmitter 120 may transmit the DL signal via a DL channel such as a PDCCH or a PDSCH. For example, when a cell of the gNB 100 functions as a serving cell (or a source cell), the transmitter 120 may transmit a message regarding conditional reconfiguration of the UE 200 to a neighboring cell based on the flight path of the UE 200. The message may be a message regarding CHO (Handover Request) or a message regarding Conditional PSCell Change / Addition (SN Modification Request / SN Addition Request).

[0096] In such a case, the message may include an information element for specifying a flight path of the UE 200. The flight path of the UE 200 may be specified by an information element (e.g., flightPathInfoReport) included in a message (e.g., UEInformationResponse) received from the UE 200. The message may include an information element (e.g., Estimated Arrival Probability) for specifying reachability to a neighboring cell based on the flight path of the UE 200.

[0097] The control unit 130 controls the gNB 100. The control unit 130 executes control related to the conditional reconfiguration of the UE 200.

[0098] For example, when the cell of the gNB 100 functions as a serving cell (or a source cell), the control unit 130 may determine a neighboring cell that is the destination of a message based on a flightPathInfoReport received from the UE 200. Specifically, the control unit 130 may estimate a flight path (waypoint) of the UE 200 based on the flightPathInfoReport, and may determine not to transmit a message to neighboring cells whose physical distance from the estimated flight path is farther than a threshold, but to transmit a message to neighboring cells whose physical distance from the estimated flight path is closer than a threshold. The control unit 130 may estimate a flight path (waypoint) of the UE 200 based on the flightPathInfoReport, and may determine an estimated arrival probability based on the estimated flight path.

[0099] For example, when the cell of the gNB 100 functions as a candidate cell (or a target cell), the control unit 130 may release radio resources related to the conditional reconfiguration when an information element included in the message satisfies a specific condition. Note that the release of radio resources may include not reserving radio resources in the first place, in addition to releasing reserved radio resources.

[0100] Specifically, in a case where the information element included in the message is Estimated Arrival Probability, the control unit 130 may release radio resources related to conditional reconfiguration when the Estimated Arrival Probability is smaller than a threshold, and may secure radio resources related to conditional reconfiguration when the Estimated Arrival Probability is larger than the threshold. That is, the specific condition may include a condition (hereinafter, a first condition) in which the Estimated Arrival Probability is smaller than a threshold.

[0101] In a case where the information element included in the message is the flight path of UE 200, control unit 130 may release radio resources related to conditional reconfiguration when the physical distance from the flight path is farther than a threshold, and may secure radio resources related to conditional reconfiguration when the physical distance from the flight path is closer than the threshold. That is, the specific condition may include a condition (hereinafter, second condition) that the physical distance from the flight path is farther than a threshold.

[0102] The control unit 130 may release the radio resources related to the conditional reconfiguration when there is no access from the UE 200 within a certain period of time. The certain period of time may be specified by an existing parameter (e.g., TXnRELOCprep) or a newly defined parameter. That is, the specific condition may include a condition (third condition) that there is no access from the UE 200 within a certain period of time.

[0103] Here, the specific condition may be a combination of two or more conditions selected from the first to third conditions. For example, the specific condition may be a combination of the first condition and the second condition, or a combination of the first condition and the third condition.

[0104] (3) Example of base station operation An example of the operation of a base station regarding conditional reconfiguration will be described below. As shown in Fig. 6, a case will be illustrated in which gNB100#1 to gNB100#7 exist and the cell of gNB100#1 is the serving cell (or source cell) of UE200. The cells of gNB100#1 to gNB100#5 may be considered to be neighboring cells.

[0105] (3.1) Issues In an environment where the quality of the gNB 100 beam (which may also be referred to as the NR beam) changes drastically, there is a possibility that handover failures of UE 200 flying in the air may increase. On the other hand, since conditional reconfiguration requires securing radio resources of candidate cells (neighboring cells) in advance, improving the utilization efficiency of radio resources is a challenge.

[0106] (3.2) Example of operation In order to improve the utilization efficiency of radio resources, gNB100#1 to gNB10#7 perform the following operations.

[0107] For example, the gNB 100#1 having the serving cell (or source cell) of the UE 200 may transmit a message regarding conditional reconfiguration of the UE 200 to a neighboring cell based on the flight path of the UE 200. The message may be a message regarding CHO (Handover Request) or a message regarding Conditional PSCell Change / Addition (SN Modification Request / SN Addition Request).

[0108] Specifically, gNB100#1 may determine the neighboring cells that are the destination of the message based on the flightPathInfoReport received from UE200. For example, gNB100#1 may transmit the message to neighboring cells (gNB100#2 and gNB100#3) that are closer in physical distance from the flight path of UE200 than a threshold, without transmitting the message to neighboring cells (gNB100#4 and gNB100#5) that are farther in physical distance from the flight path (waypoint) of UE200 than a threshold.

[0109] The gNB100#1 may transmit to neighboring cells (gNB100#2 to gNB100#5) a message including an information element for identifying the flight path of the UE200. The gNB100#1 may transmit to neighboring cells (gNB100#2 to gNB100#5) a message including an information element for identifying the reachability to the neighboring cell based on the flight path of the UE200 (e.g., Estimated Arrival Probability).

[0110] For example, gNB100#2 to gNB100#5 having a candidate cell (or target cell) may release radio resources related to conditional reconfiguration when an information element included in a message satisfies a specific condition. The message may be a message related to CHO (Handover Request) or a message related to Conditional PSCell Change / Addition (SN Modification Request / SN Addition Request).

[0111] Specifically, in a case where the information element included in the message is Estimated Arrival Probability, gNB100#4 and gNB100#5 may determine that the Estimated Arrival Probability is smaller than a threshold and autonomously release the radio resources related to the conditional reconfiguration. gNB100#4 and gNB100#5 may autonomously release the radio resources related to the conditional reconfiguration when there is no access from UE200 within a certain period of time and they determine that the Estimated Arrival Probability is smaller than a threshold.

[0112] Alternatively, in a case where the information element included in the message is the flight path of UE200, gNB100#4 and gNB100#5 may determine that the physical distance from the flight path is farther than a threshold and autonomously release the radio resources related to the conditional reconfiguration. gNB100#4 and gNB100#5 may autonomously release the radio resources related to the conditional reconfiguration when there is no access from UE200 within a certain period of time and they determine that the physical distance from the flight path is farther than a threshold.

[0113] For example, in the case of CHO, as shown in Fig. 7, in step S11, the UE 200 transmits a flightPathInfoReport to the gNB 100#1. The flightPathInfoReport may be included in a UEInformationResponse.

[0114] In step S12, gNB100#1 transmits a Handover Request to neighboring cells (gNB100#2 to gNB100#5). gNB100#1 does not need to transmit a Handover Request to neighboring cells (gNB100#4 and gNB100#5) whose physical distance from the flight path (waypoint) of UE200 is farther than a threshold.

[0115] In step S13, gNB100#2 to gNB100#5 reserve radio resources for CHO. If gNB100#4 and gNB100#5 do not receive a Handover Request, they do not need to reserve radio resources for CHO.

[0116] In step S14, gNB100#4 and gNB100#5 determine that the Estimated Arrival Probability is smaller than the threshold, or that the physical distance from the flight path is farther than the threshold, and autonomously release the radio resources related to the conditional reconfiguration. Note that gNB100#2 and gNB100#3 may determine that the Estimated Arrival Probability is larger than the threshold, or that the physical distance from the flight path is closer than the threshold, and may not need to release the radio resources related to the conditional reconfiguration.

[0117] Although FIG. 7 illustrates CHO as an example of conditional reconfiguration, the conditional reconfiguration may be Conditional PSCell Change or Conditional PSCell Addition.

[0118] (4) Example of UE operation An example of UE operation regarding conditional reconfiguration will be described below. As shown in Fig. 8, an example will be given of a case where gNB100#1 to gNB100#4 exist and cell C#1 of gNB100#1 is the serving cell (or source cell) of UE200. Cells C#2 to C#4 of gNB100#1 to gNB100#5 may be considered as candidate cells.

[0119] (4.1) Issues Since the propagation environment of UE 200 is clear, it is expected that many cells and / or beams will be observed. Therefore, there is a possibility that two or more candidate cells may simultaneously satisfy the conditions, and it is not possible to connect to an appropriate candidate cell.

[0120] (4.2) Example of operation In order to connect to an appropriate candidate cell, UE200 performs the following operation. Fig. 8 illustrates a case where the number of beams satisfying the specific quality in cell C#2 is 7, the number of beams satisfying the specific quality in cell C#3 is 5, and the number of beams satisfying the specific quality in cell C#4 is 3. As described above, existing parameters (e.g., absThreshSS-BlocksConsolidation, absThreshCSI-RS-Consolidation, etc.) may be used as the parameters defining the specific quality. A new parameter may be introduced as the parameter defining the specific quality. The parameter defining the specific number may be referred to as NumberOfGoodBeam.

[0121] The UE 200 may select a target cell to connect to through conditional reconfiguration based on a condition regarding the number of beams of each of two or more candidate cells. As described above, the condition regarding the number of beams may include at least one of a condition that the number of beams satisfying a specific quality is the maximum and a condition that the number of beams satisfying the specific quality exceeds a specific number. The parameter defining the specific number may be referred to as NumberOfGoodBeam.

[0122] For example, when the reception qualities of cells C#2 to C#4 are the same, UE200 may select cell C#2, which has the largest number of beams that satisfy a specific quality, as the target cell. However, UE200 may select the target cell by prioritizing the condition related to the reception quality over the condition related to the number of beams. Therefore, when the reception quality of cell C#4 is higher than the reception quality of cell C#2, UE200 may select cell C#4 as the target cell.

[0123] Alternatively, when the specific number is set to 5, the UE 200 may exclude cell C#4, which has fewer beams satisfying the specific quality than the specific number, from the target cells. In such a case, when the reception qualities of cells C#2 and C#3 are the same, the UE 200 may select cell C#2, which has the largest number of beams satisfying the specific quality, as the target cell. Note that even if the reception quality of cell C#4 is higher than the reception quality of cell C#2, the UE 200 may select the target cell from cell C#2 and cell C#3 without selecting cell C#4 as the target cell.

[0124] Furthermore, a minimum number of beams to be used for measuring the reception quality of neighboring cells may be defined. This minimum number may be referred to as minimumNrofSS-BlocksToAverage. minimumNrofSS-BlocksToAverage may be set by an RRC message (e.g., MeasObjectNR).

[0125] For example, when the minimum number is set to 5, UE200 may not measure the reception quality of cell C#4, which has fewer beams satisfying the specific quality than the minimum number, and may exclude cell C#4 from the measurement report. In other words, UE200 measures the reception quality of cells C#2 and C#3, which have more beams satisfying the specific quality than the minimum number. The reception quality of cell C#2 may be the average of the reception qualities of the seven beams, and the reception quality of cell C#3 may be the average of the reception qualities of the five beams.

[0126] In addition, a maximum number of beams used for measuring the reception quality of neighboring cells may be defined. This maximum number may be referred to as maxNrofSS-BlocksToAverage. maxNrofSS-BlocksToAverage may be set by an RRC message (e.g., MeasObjectNR). maxNrofSS-BlocksToAverage may be a known parameter.

[0127] (5) Actions and Effects In an embodiment, the gNB100 having the serving cell (or source cell) transmits a message regarding conditional reconfiguration of the UE200 to a neighboring cell based on the flight path of the UE200.

[0128] For example, the gNB 100 may determine the neighboring cell that is the destination of the message based on the flightPathInfoReport received from the UE 200. Such a configuration eliminates the need to reserve radio resources for neighboring cells to which the UE 200 is unlikely to connect in conditional reconfiguration, thereby improving the utilization efficiency of radio resources.

[0129] Alternatively, the gNB 100 transmits to the neighboring cell a message including at least one of an information element for specifying the flight path of the UE 200 and an information element for specifying reachability to the neighboring cell based on the flight path of the UE 200. With this configuration, the neighboring cell can appropriately determine whether to reserve or release radio resources based on the information element included in the message.

[0130] In the embodiment, the gNB 100 having the candidate cell (or the target cell) releases radio resources related to the conditional reconfiguration when an information element included in the message satisfies a specific condition. With this configuration, the radio resources of a neighboring cell to which the UE 200 is unlikely to connect through the conditional reconfiguration are released, thereby improving the utilization efficiency of the radio resources.

[0131] In the embodiment, the UE 200 may select a target cell based on a condition regarding the number of beams of each of two or more candidate cells. With this configuration, when a case is assumed in which two or more candidate cells simultaneously satisfy the condition, the UE 200 can appropriately select a target cell to which the UE 200 is connected by conditional reconfiguration.

[0132] (6) Other embodiments The present invention has been described above in accordance with the embodiments, but it will be obvious to those skilled in the art that the present invention is not limited to these descriptions and that various modifications and improvements are possible.

[0133] Although the above disclosure mainly describes NR, the above disclosure is not limited thereto. The above disclosure may be applied to LTE. In such a case, NG-RAN may be read as E-UTRAN, and gNB may be read as eNB. The above disclosure may be applied to a case where NR and LTE are mixed.

[0134] The block diagrams (FIGS. 4 and 5) used in the description of the above-described embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of 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 (for example, by wire, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining the single device or the multiple devices with software.

[0135] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, regard, 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.

[0136] Furthermore, the above-described gNB100 and UE200 (the device) may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 9 is a diagram showing an example of the hardware configuration of the device. As shown in Figure 9, the device 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.

[0137] 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.

[0138] Each functional block of the device (see FIG. 4) is realized by any hardware element of the computer device or a combination of the hardware elements.

[0139] 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.

[0140] 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, a register, and the like.

[0141] 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-mentioned embodiments. Furthermore, the various processes described above may be executed by one 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.

[0142] The memory 1002 is a computer-readable recording medium and may be configured by, for example, at least one of 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 can store a program (program code), a software module, etc., that can execute a method according to an embodiment of the present disclosure.

[0143] 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 appropriate medium including at least one of memory 1002 and storage 1003.

[0144] 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.

[0145] 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).

[0146] The input device 1005 is an input device (for example, 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 (for example, a display, a speaker, an LED lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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), 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 and 5G) may also be applied.

[0151] 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.

[0152] In the present disclosure, a specific operation described as being performed by a base station may 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 (for example, but not limited to, an MME or an S-GW). 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 (for example, an MME and an S-GW) may also be used.

[0153] 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 / output via multiple network nodes.

[0154] The input and output information may be stored in a specific location (for example, 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 sent to another device.

[0155] 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).

[0156] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, notification of predetermined information (e.g., notification that "X is true") is not limited to being done explicitly, but may be done implicitly (e.g., by not notifying the predetermined information).

[0157] 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.

[0158] 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.

[0159] 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.

[0160] Note that terms explained 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.

[0161] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0162] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, relative values ​​from a predetermined value, or other corresponding information. For example, a radio resource may be indicated by an index.

[0163] 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.

[0164] 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.

[0165] 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 service by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0166] 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.

[0167] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0168] 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.

[0169] At least one of the base station and the mobile station may be called 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 body, the mobile body itself, etc. The mobile body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (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 also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0170] 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 communication between terminals (for example, "side"). For example, terms such as uplink channel and downlink channel may be read as side channel.

[0171] 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.

[0172] A radio frame may be composed of one or more frames in the time domain, each of which may be called a subframe.

[0173] A subframe may further be composed of one or more slots in the time domain, and may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0174] Numerology may be a communication parameter applied to at least one of transmission and 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 a transceiver in the frequency domain, and specific windowing operations performed by a transceiver in the time domain.

[0175] A slot may consist of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol). A slot may be a time unit based on numerology.

[0176] A slot may include multiple minislots. Each minislot may consist of one or multiple 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.

[0177] 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.

[0178] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called 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.

[0179] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) to each user terminal in TTI units. However, the definition of TTI is not limited to this.

[0180] 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.

[0181] 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. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0182] A TTI having a time length of 1 ms may be called 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 called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0183] 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.

[0184] 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. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may also be determined based on numerology.

[0185] 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. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0186] 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, or the like.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] 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."

[0191] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. 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, etc. may be changed in various ways.

[0192] 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.

[0193] The reference signal may also be abbreviated as Reference Signal (RS), and may also be called a pilot depending on the applicable standard.

[0194] 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."

[0195] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0196] 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.

[0197] When used in this disclosure, the terms "include," "including," and variations thereof are intended to be inclusive, similar to the term "comprising." Furthermore, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0198] 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.

[0199] 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.

[0200] 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."

[0201] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure. [Explanation of symbols]

[0202] 10. Wireless communication systems 20 NG-RAN 100 gNB 110 Receiving unit 120 Transmitter 130 control section 200 UE 210 Radio signal transmitter / receiver 220 Amplifier section 230 Modulation and Demodulation Unit 240 Control signal / reference signal processing section 250 Encoding / Decoding Unit 260 Data transmission and reception unit 270 Control Unit 1001 processor 1002 memory 1003 Storage 1004 Communication equipment 1005 Input Device 1006 Output Device 1007 Bus

Claims

1. a control unit that selects a target cell from two or more candidate cells in conditional reconfiguration; a transmitter that transmits a message for connecting to the target cell in the conditional reconfiguration, The control unit selects the target cell based on a condition regarding the number of beams of each of the two or more candidate cells. Terminal.

2. The condition regarding the number of beams includes at least one of a condition that the number of beams satisfying a specific quality is the maximum and a condition that the number of beams satisfying the specific quality exceeds a specific number. The terminal according to claim 1 .

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