Terminal, communication system, and communication method

Abstract

This terminal comprises a control unit which determines a channel access mechanism on the basis of a condition, a reception unit which performs sensing on the basis of the determined channel access mechanism, and a transmission unit which performs transmission on the basis of the sensing result, wherein the determined channel access mechanism is listen before talk (LBT) in which a sensing period is fixed.

Description

Terminal and communication method

[0001] The present invention relates to a terminal and a communication method in a wireless communication system.

[0002] For NR (New Radio) (also known as "5G"), the successor system to LTE (Long Term Evolution), technologies are being considered that satisfy the requirements of a large-capacity system, high-speed data transmission speed, low latency, simultaneous connection of a large number of terminals, low cost, and low power consumption (for example, Non-Patent Document 1).

[0003] NR Release 17 is considering the use of a higher frequency band than in previous releases (e.g., Non-Patent Document 2). For example, in the frequency band from 52.6 GHz to 71 GHz, applicable numerology including subcarrier spacing, channel bandwidth, etc., physical layer design, and expected interference in actual wireless communications are being considered.

[0004] 3GPP TS 38.300 V16.4.0 (2020-12) 3GPP TS 38.306 V16.3.0 (2020-12)

[0005] In newly operated frequency bands using higher frequencies than conventional ones, both channel access with LBT (Listen Before Talk) and channel access without LBT are supported. For example, it is necessary to determine the channel access mechanism to comply with regulations in each country. However, the conditions for determining the channel access mechanism and the detailed operation of sensing have not been clear.

[0006] The present invention has been made in view of the above points, and makes it possible to determine a channel access mechanism in a wireless communication system depending on communication conditions.

[0007] According to the disclosed technology, a terminal is provided which has a control unit that determines a channel access mechanism based on conditions, a receiving unit that performs sensing based on the determined channel access mechanism, and a transmitting unit that performs transmission based on the results of the sensing, wherein the determined channel access mechanism is LBT (Listen before talk) with a fixed sensing period.

[0008] According to the disclosed technique, in a wireless communication system, a channel access mechanism can be determined depending on communication conditions.

[0009] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a frequency range according to an embodiment of the present invention. FIG. 3 is a flowchart illustrating an example (1) of channel access according to an embodiment of the present invention. FIG. 4 is a flowchart illustrating an example (2) of channel access according to an embodiment of the present invention. FIG. 5 is a flowchart illustrating an example (3) of channel access according to an embodiment of the present invention. FIG. 6 is a flowchart illustrating an example (4) of channel access according to an embodiment of the present invention. FIG. 7 is a diagram illustrating an example of the functional configuration of a base station 10 according to an embodiment of the present invention. FIG. 8 is a diagram illustrating an example of the functional configuration of a terminal 20 according to an embodiment of the present invention. FIG. 9 is a diagram illustrating an example of the hardware configuration of a base station 10 or a terminal 20 according to an embodiment of the present invention.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0011] In the operation of the wireless communication system according to the embodiment of the present invention, existing technology is used as appropriate. However, the existing technology is, for example, the existing LTE, but is not limited to the existing LTE. Furthermore, the term "LTE" used in this specification has a broad meaning including LTE-Advanced and systems subsequent to LTE-Advanced (e.g., NR), unless otherwise specified.

[0012] In addition, in the embodiments of the present invention described below, terms such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel) used in existing LTE are used. This is for convenience of description, and similar signals, functions, etc. may be called by other names. In addition, the above-mentioned terms in NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, etc. However, even if a signal is used in NR, it is not necessarily stated as "NR-".

[0013] Furthermore, in the embodiment of the present invention, the duplex method may be a time division duplex (TDD) method, a frequency division duplex (FDD) method, or another method (for example, flexible duplex, etc.).

[0014] Furthermore, in the embodiments of the present invention, "configuring" radio parameters etc. may mean that predetermined values ​​are pre-configured, or that radio parameters notified from the base station 10 or the terminal 20 are set.

[0015] Fig. 1 is a diagram showing an example of the configuration of a wireless communication system according to an embodiment of the present invention. As shown in Fig. 1, the wireless communication system according to the embodiment of the present invention includes a base station 10 and a terminal 20. Although Fig. 1 shows one base station 10 and one terminal 20, this is an example, and there may be a plurality of each.

[0016] The base station 10 is a communication device that provides one or more cells and performs wireless communication with the terminal 20. The physical resources of a wireless signal are defined in the time domain and the frequency domain. The time domain may be defined by the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols, and the frequency domain may be defined by the number of subcarriers or the number of resource blocks. The base station 10 transmits a synchronization signal and system information to the terminal 20. The synchronization signal is, for example, NR-PSS and NR-SSS. The system information is, for example, transmitted via NR-PBCH and is also referred to as broadcast information. The synchronization signal and system information may also be referred to as SSB (SS / PBCH block). As shown in FIG. 1 , the base station 10 transmits control signals or data to the terminal 20 via DL (Downlink) and receives control signals or data from the terminal 20 via UL (Uplink). Both the base station 10 and the terminal 20 are capable of transmitting and receiving signals by performing beamforming. Furthermore, both the base station 10 and the terminal 20 can apply MIMO (Multiple Input Multiple Output) communication to DL or UL. Furthermore, both the base station 10 and the terminal 20 may communicate via a secondary cell (SCell: Secondary Cell) and a primary cell (PCell: Primary Cell) using CA (Carrier Aggregation). Furthermore, the terminal 20 may communicate via a primary cell of the base station 10 and a primary secondary cell group cell (PSCell: Primary SCG Cell) of another base station 10 using DC (Dual Connectivity).

[0017] The terminal 20 is a communication device equipped with a wireless communication function, such as a smartphone, a mobile phone, a tablet, a wearable terminal, or an M2M (Machine-to-Machine) communication module. As shown in Fig. 1, the terminal 20 receives control signals or data from the base station 10 via DL and transmits control signals or data to the base station 10 via UL, thereby utilizing various communication services provided by the wireless communication system. The terminal 20 also receives various reference signals transmitted from the base station 10 and measures propagation path quality based on the reception results of the reference signals.

[0018] FIG. 2 is a diagram showing an example of a frequency range in an embodiment of the present invention. In the NR specifications of 3GPP Release 15 and Release 16, for example, operation of a frequency band of 52.6 GHz or higher is being considered. As shown in FIG. 2, the currently specified frequency range (FR) 1 is a frequency band from 410 MHz to 7.125 GHz, with a subcarrier spacing (SCS) of 15, 30, or 60 kHz and a bandwidth of 5 MHz to 100 MHz. FR2 is a frequency band from 24.25 GHz to 52.6 GHz, with a SCS of 60, 120, or 240 kHz and a bandwidth of 50 MHz to 400 MHz. For example, the newly operated frequency band may be from 52.6 GHz to 71 GHz, or from 52.6 GHz to 114.25 GHz, or may include an unlicensed band.

[0019] As for regulations in the above-mentioned frequency bands, for example, CEPT (European Conference of Postal and Telecommunications Administrations) has regulations that make LBT (Listen before talk) mandatory. There are also regulations that require LBT not to be performed. Which regulation to use is determined by the mobility of the terminal 20, for example, whether the terminal 20 is a fixed terminal or a mobile terminal.

[0020] Furthermore, for example, the FCC (Federal Communications Commission) does not specify requirements for reducing interference in the 57-71 GHz band. Furthermore, for example, Japanese regulations require carrier sensing before starting transmission with a transmission power exceeding 10 mW. Note that carrier sensing has a mechanism similar to LBT, but the details have not yet been determined.

[0021] In addition, 3GPP is considering supporting both channel access with and without LBT when the base station 10 or the terminal 20 starts channel occupation. Regarding LBT mechanisms, omni-directional LBT, directional LBT, and receiver-executed LBT type mechanisms are also being considered.

[0022] In addition, it is being considered whether operational restrictions are necessary for channel access that does not perform LBT. For example, in order to satisfy regulations, it is being considered whether operational restrictions are necessary for channel access that does not perform LBT when Automatic Transmit Power Control (ATPC), Dynamic Frequency Selection (DFS), long-term sensing, or other interference reduction mechanisms are present.

[0023] In addition, mechanisms or conditions for switching between channel access that implements LBT and channel access that does not implement LBT (assuming that it is permitted by local regulations, for example) are being considered.

[0024] For example, in the 60 GHz band, support for two media access mechanisms, one that implements LBT and one that does not implement LBT, is under consideration.

[0025] For example, support for three types of channel access, including no LBT, long-term sensing, and short-term sensing, is being considered. For example, no LBT may be applied when the conditions for EIRP (Equivalent Isotopically Radiated Power), transmit power, channel occupancy duty cycle, spatial multiplexing characteristics, etc. are met. Furthermore, long-term sensing is an approach that enables beam reuse when many beam collisions occur. Short-term sensing is a type of LBT.

[0026] For example, there are three types of LBT: 1) to 3) shown below.

[0027] 1) LBT, in which the sensing period is determined randomly. For example, Type 1 LBT in Release 16NR-U (NR system using unlicensed bands) applies. Although the possibility of transmission collisions between multiple devices is low, transmission timing delays occur due to backoff.

[0028] 2) LBT with a fixed sensing period. For example, Type 2a / 2b LBT in Release 16NR-U. Although there is a high possibility of transmission collisions between multiple devices, there is little delay in transmission timing because there is no backoff.

[0029] 3) Transmit immediately without sensing, for example, Type 2c LBT in Release 16NR-U.

[0030] Here, LBT, in which the sensing period is fixed in length, has been studied in the 60 GHz band, but the conditions for determining the channel access mechanism and the detailed sensing operation have not been clear. Therefore, we propose determining the channel access mechanism in, for example, an unlicensed band in the 60 GHz band.

[0031] 3 is a flowchart for explaining an example (1) of channel access in an embodiment of the present invention. In step S11, the terminal 20 performs sensing. In the following step S12, the terminal 20 compares the sensing result with a certain threshold. In the following step S13, the terminal 20 may switch, change, determine, set, or report the channel access mechanism based on the comparison in step S12. Note that the sensing in step S11 may be long-term sensing.

[0032] The threshold used in step S12 may be set to a fixed value, such as X dB or a power density per band such as X dB / MHz. The threshold is variable and may be determined based on at least one of the sensing bandwidth, the sensing directionality, and the sensing periodicity, for example.

[0033] As an example of switching the channel access mechanism in step S13, if the sensing result exceeds a threshold, a transmitting device may perform directional LBT with random backoff, and if the sensing result does not exceed the threshold, the transmitting device may perform directional LBT without random backoff. The transmitting device may be a base station 10 or a terminal 20.

[0034] As an example of switching the channel access mechanism in step S13, if the sensing result exceeds a threshold, a receiving device may report to other devices that it will perform directional LBT with random backoff. If the sensing result does not exceed the threshold, a transmitting device may not report, or may perform directional LBT without random backoff. The receiving device may be a base station 10 and may send the report to the terminal 20, or the terminal 20 may send the report to the base station 10.

[0035] The sensing in step S11 shown in FIG. 3 may be performed as shown in 1)-4) below.

[0036] 1) Sensing Periodicity Sensing may be performed periodically. The period may be predefined in a specification, may be set by a Radio Resource Control (RRC) setting, or may be set by a Medium Access Control-Control Element (MAC-CE). Furthermore, sensing may be performed semi-persistently, and its enablement or disablement may be switched. The enablement or disablement may be switched according to a specific condition, an RRC setting, or a MAC-CE setting.

[0037] 2) Sensing Range Sensing may be performed omnidirectionally in the entire range around the target device. Sensing may also be directional. Sensing may be performed in a single direction around the target device. Sensing may also be performed in multiple directions around the target device, or by switching directions to sense the entire range around the target device.

[0038] 3) Sensing Threshold The threshold used for sensing may be set to a fixed value. For example, it may be X dB or a power density per band such as X dB / MHz. The threshold is variable and may be changed based on, for example, the sensing bandwidth, the sensing directionality, the sensing periodicity, etc.

[0039] 4) Sensing Mechanism Sensing may use the results of existing channel occupancy measurements or may use the results of other RRM (Radio Resource Management).

[0040] The channel access mechanism used in step S13 shown in FIG. 3 may be an LBT mechanism. For example, the target range of the LBT sensing may be performed in the entire range around the target device. The sensing may also be directional. The target device may be sensed in a single direction. The target device may also be sensed in multiple directions, or the entire range around the target device may be sensed by switching directions.

[0041] The timing to start sensing the LBT may be, for example, immediately before transmission as in LBE (Load Based Equipment), or may be, for example, periodic as in FBE (Frame Based Equipment).

[0042] A random backoff may be applied to the sensing period of the LBT. Alternatively, the sensing period of the LBT may be a fixed period without applying a random backoff.

[0043] The channel access mechanism used in step S13 shown in Fig. 3 may be a channel access mechanism other than LBT. For example, Automatic Transmit Power Control (ATPC) may be applied to transmit power control, and Dynamic Frequency Selection (DFS) may be applied to frequency resource switching. Here, the operations of ATPC, DFS, etc. may be specified in non-3GPP specifications, or may be described in 3GPP specifications as following the non-3GPP specifications.

[0044] 3, the channel access mechanism used in step S13 may be a non-LBT mechanism. That is, the LBT mechanism and the non-LBT mechanism may be switched between. The non-LBT mechanism may mean that no channel access mechanism is applied, or that a channel access mechanism other than LBT is used.

[0045] A plurality of types of channel access mechanisms, such as LBT or non-LBT, having different parameters as described above may be switched in step S13 shown in Fig. 3. Also, in step S13 shown in Fig. 3, a mode in which LBT is performed and a mode in which LBT is not performed may be switched.

[0046] 3, a period during which the determined or switched channel access mechanism is applicable may be set. The period may be a fixed period, may be determined based on the result of comparing the sensing result with a threshold value in step S12, may be determined based on the timing at which the sensing result is obtained in step S11, or may be the same period as the sensing in step S11.

[0047] Note that the result of sensing in step S11 shown in FIG. 3 may be utilized. For example, the sensing result may be periodically reported to another device. For example, an existing RRM may be reused. The existing RRM may be, for example, radio link monitoring (RLM), beam failure recovery (BFR), candidate beam detection (CBD), L1 measurement, intraband measurement, interband measurement, or channel occupancy measurement.

[0048] For example, based on the reported sensing result, the reporting device may configure a channel access mechanism to be used for the reporting device. For example, the reporting device may be the base station 10 and the reporting device may be the terminal 20.

[0049] For example, based on sensing results acquired by a certain device, the device may determine or set a channel access mechanism to be used by the device itself, or the device may determine or set a channel access mechanism to be used by a device located in the same cell or frequency band as the device. For example, the device may be a base station 10, and the device located in the same cell or frequency band as the device may be a terminal 20.

[0050] For example, the sensing period in a fixed-sensing LBT may be 5 microseconds. This corresponds to one sensing period in an LBT with random backoff, which is one of the requirements for the 60 GHz band. The sensing period in a fixed-sensing LBT may also be 5 x N microseconds. The sensing period can be flexibly determined in units of 5 microseconds. A different analog beam can be applied to sensing every 5 microseconds.

[0051] 4 is a flowchart for explaining an example (2) of channel access in an embodiment of the present invention. In step S21, the terminal 20 determines whether or not it is currently within the COT acquired by its own device or another device. If it is within the COT (YES in S21), the process proceeds to step S22. If it is not within the COT (NO in S21), the process proceeds to step S23. In step S22, the terminal 20 uses an LBT with a fixed sensing period. On the other hand, in step S23, the terminal 20 does not use an LBT with a fixed sensing period. In the following step S24, the terminal 20 uses an LBT with a random sensing period or does not use sensing. Note that step S24 may or may not be executed.

[0052] For example, before transmission starts within the COT acquired by the terminal 20 itself or another terminal, the terminal 20 may execute an LBT with a fixed sensing period. Also, if an LBT with a fixed sensing period is not set, the terminal 20 may select and execute an LBT with a random sensing period or an LBT without sensing.

[0053] 5 is a flowchart illustrating an example (3) of channel access according to an embodiment of the present invention. In step S31, the terminal 20 determines whether the measurement result satisfies a criterion. The measurement result may be, for example, a received signal strength indicator (RSSI) measurement result or a channel occupancy rate measurement result. The criterion may be that the measurement result exceeds a certain threshold value or falls below a certain threshold value. If the measurement result satisfies the criterion (YES in S31), the process proceeds to step S32. If the measurement result does not satisfy the criterion (NO in S31), the process proceeds to step S33.

[0054] In step S32, the terminal 20 uses an LBT with a fixed sensing period. On the other hand, in step S33, the terminal 20 does not use an LBT with a fixed sensing period. In the following step S34, the terminal 20 uses an LBT with a random sensing period or does not use sensing. Note that step S34 may or may not be executed.

[0055] Also, in step S13 shown in Figure 3, when switching between a mode in which LBT is executed and a mode in which LBT is not executed, if the mode in which LBT is executed is set, LBT with a fixed sensing period may be applied to a specific signal or channel, or the base station 10 may notify the terminal 20 that LBT with a fixed sensing period will be applied.

[0056] The specific signal or channel may be, for example, at least one of 1) to 3) shown below.

[0057] 1) SSB 2) PRACH 3) PUCCH (e.g., with periodic resources configured)

[0058] In addition, the terminal 20 may determine whether to use LBT with a fixed sensing period based on at least one of 1)-4) below.

[0059] 1) Definition by use 2) Configuration by RRC 3) Configuration by MAC-CE 4) Indication by DCI (the ChannelAccess-CPext-CAPC field included in DCI format 0_1 ​​may be reused)

[0060] Note that any combination of 1) to 4) above may be used. For example, whether or not to use an LBT with a fixed sensing period may be determined by a setting by RRC and an instruction by DCI. For example, the RRC may be configured to select whether or not to use an LBT with a fixed sensing period, and an instruction may be given as to whether or not to use an LBT with a fixed sensing period before a PUSCH transmission scheduled by an UL grant DCI. The RRC or the UL grant DCI may be replaced with a MAC-CE.

[0061] 6 is a flowchart illustrating an example (4) of channel access according to an embodiment of the present invention. In step S41, the terminal 20 determines a table to be used for channel access mechanism notification based on the band to be used. The band to be used may be, for example, a specific frequency band or an unlicensed band. The specific frequency band may be, for example, 52.6 GHz-71 GHz, or 52.6 GHz or higher, or a frequency band supported by FRx (x is 2 or greater).

[0062] In step S42, the terminal 20 receives a channel access mechanism notification by DCI with reference to the determined table. The table in which the entry designated by the DCI is defined may include, for example, a channel access type and parameters related to CP extension. The table in which the entry designated by the DCI is defined may be configured by reusing unused fields of a table in the existing technology, or a new table may be defined separately from the table in the existing technology. Whether to use the table in the existing technology or the newly defined table may be configured by RRC, may be configured by MAC-CE, may be notified by DCI, or may be configured by a combination of RRC, MAC-CE, and DCI.

[0063] The above-described channel access operation may be performed not only by the terminal 20 but also by the base station 10 in the same manner.

[0064] According to the above-described embodiment, the base station 10 and the terminal 20 can determine the channel access mechanism based on whether they are within the COT, the measurement results, the band to be used, and the like.

[0065] That is, in a wireless communication system, a channel access mechanism can be determined depending on the communication situation.

[0066] (Device Configuration) Next, a functional configuration example of the base station 10 and the terminal 20 that execute the processes and operations described above will be described. The base station 10 and the terminal 20 include functions for implementing the above-described embodiments. However, the base station 10 and the terminal 20 may each include only a part of the functions of the embodiments.

[0067] <Base Station 10> Figure 7 is a diagram showing an example of the functional configuration of the base station 10 according to an embodiment of the present invention. As shown in Figure 7, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Figure 7 is merely an example. The names of the functional divisions and functional units may be any as long as they can perform the operations according to the embodiment of the present invention.

[0068] The transmitter 110 has a function of generating a signal to be transmitted to the terminal 20 side and transmitting the signal wirelessly. The transmitter 110 also transmits inter-network node messages to other network nodes. The receiver 120 has a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of higher layers from the received signals. The transmitter 110 also has a function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, etc. to the terminal 20. The receiver 120 also receives inter-network node messages from other network nodes.

[0069] The setting unit 130 stores preset setting information and various setting information to be transmitted to the terminal 20. The setting information includes, for example, information relating to channel access settings.

[0070] As described in the embodiments, the control unit 140 controls the setting of channel access. The control unit 240 also controls LBT. The control unit 140 also executes scheduling. The function unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and the function unit related to signal reception in the control unit 140 may be included in the receiving unit 120.

[0071] <Terminal 20> Fig. 8 is a diagram showing an example of the functional configuration of terminal 20 in an embodiment of the present invention. As shown in Fig. 8, terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Fig. 8 is merely an example. The names of the functional divisions and functional units may be any as long as they can execute the operations related to the embodiment of the present invention.

[0072] The transmitter 210 creates a transmission signal from transmission data and transmits the transmission signal wirelessly. The receiver 220 wirelessly receives various signals and acquires higher layer signals from the received physical layer signals. The receiver 220 also has a function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL / SL control signals, and the like transmitted from the base station 10. For example, the transmitter 210 transmits a PSCCH (Physical Sidelink Control Channel), a PSSCH (Physical Sidelink Shared Channel), a PSDCH (Physical Sidelink Discovery Channel), a PSBCH (Physical Sidelink Broadcast Channel), and the like to another terminal 20 as D2D communication, and the receiver 220 receives the PSCCH, PSSCH, PSDCH, or PSBCH, and the like, from the other terminal 20.

[0073] The setting unit 230 stores various setting information received from the base station 10 by the receiving unit 220. The setting unit 230 also stores setting information that is set in advance. The setting information includes, for example, information related to channel access settings.

[0074] As described in the embodiment, the control unit 240 controls the setting of channel access. The control unit 240 also controls LBT. The function unit related to signal transmission in the control unit 240 may be included in the transmitting unit 210, and the function unit related to signal reception in the control unit 240 may be included in the receiving unit 220.

[0075] (Hardware Configuration) The block diagrams (FIGS. 7 and 8) used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and 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 directly or indirectly connected (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may also be realized by combining software with the single device or the multiple devices.

[0076] Functions include, but are not limited to, judgment, determination, assessment, 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 these functions are implemented.

[0077] For example, the base station 10, the terminal 20, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 9 is a diagram illustrating an example of the hardware configuration of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. The base station 10 and the terminal 20 described above may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0078] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the base station 10 and the terminal 20 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.

[0079] Each function in the base station 10 and the terminal 20 is realized by loading specified software (programs) onto hardware such as the processor 1001, the memory device 1002, etc., so that the processor 1001 performs calculations, controls communication by the communication device 1004, and controls at least one of reading and writing data in the memory device 1002 and the auxiliary memory device 1003.

[0080] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control unit 140, control unit 240, etc. may be realized by the processor 1001.

[0081] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002 and executes various processes in accordance with the programs. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 140 of the base station 10 shown in FIG. 7 may be implemented by a control program stored in the storage device 1002 and running on the processor 1001. For example, the control unit 240 of the terminal 20 shown in FIG. 8 may be implemented by a control program stored in the storage device 1002 and running on the processor 1001. While the above-described various processes have been described as being executed by one processor 1001, they may also 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 also be transmitted from a network via a telecommunications line.

[0082] The storage device 1002 is a computer-readable recording medium and may be configured, for example, by at least one of a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a random access memory (RAM), etc. The storage device 1002 may also be called a register, a cache, a main memory, etc. The storage device 1002 can store executable programs (program codes), software modules, etc. for implementing a communication method according to an embodiment of the present disclosure.

[0083] The secondary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. The above-mentioned storage medium may be, for example, a database, a server, or other appropriate medium including at least one of the storage device 1002 and the secondary storage device 1003.

[0084] 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 referred to as, for example, a network device, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, a transmission / reception antenna, an amplifier unit, a transmission / reception unit, a transmission path interface, etc. may be realized by the communication device 1004. The transmission / reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated.

[0085] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts 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).

[0086] Furthermore, each device such as the processor 1001 and the storage device 1002 is connected by 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.

[0087] Furthermore, the base station 10 and the terminal 20 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.

[0088] (Summary of the embodiment) As described above, according to the embodiment of the present invention, there is provided a terminal having a control unit that determines a channel access mechanism based on conditions, a receiving unit that performs sensing based on the determined channel access mechanism, and a transmitting unit that performs transmission based on the results of the sensing, wherein the determined channel access mechanism is LBT (Listen before talk) with a fixed sensing period.

[0089] With the above configuration, the base station 10 and the terminal 20 can determine the channel access mechanism based on whether they are within the COT, the measurement results, the band to be used, etc. In other words, in a wireless communication system, the channel access mechanism can be determined depending on the communication situation.

[0090] The fixed sensing period may be in units of 5 microseconds. This configuration allows the terminal 20 to flexibly determine the sensing period and apply different analog beams for sensing.

[0091] The condition may be that the current time is within a COT (Channel Occupancy Time) acquired by the base station 10 or another device. With this configuration, the base station 10 and the terminal 20 can determine a channel access mechanism based on whether or not they are within the COT.

[0092] The condition may be that a result of a received signal strength indicator (RSSI) measurement or a result of a channel utilization rate measurement is below a threshold. With this configuration, the base station 10 and the terminal 20 can determine a channel access mechanism based on the result of the RSSI measurement or the result of the channel utilization rate measurement.

[0093] The condition may be that an entry in a table specifying a channel access mechanism determined based on a band to be used is signaled by the DCI. With this configuration, the terminal 20 can determine the channel access mechanism using a table defined according to a band to be used.

[0094] Furthermore, according to an embodiment of the present invention, a communication method is provided in which a terminal executes a control procedure for determining a channel access mechanism based on conditions, a receiving procedure for performing sensing based on the determined channel access mechanism, and a transmitting procedure for performing transmission based on the results of the sensing, and the determined channel access mechanism is LBT (Listen before talk) with a fixed sensing period.

[0095] With the above configuration, the base station 10 and the terminal 20 can determine the channel access mechanism based on whether they are within the COT, the measurement results, the band to be used, etc. In other words, in a wireless communication system, the channel access mechanism can be determined depending on the communication situation.

[0096] (Supplementary Notes on the Embodiments) Although the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention; matters described in two or more items may be used in combination as needed, and matters described in one item may apply to matters described in another item (as long as there is no contradiction). Boundaries between functional units or processing units in functional block diagrams do not necessarily correspond to boundaries between physical components. The operations of multiple functional units may be performed by a single physical component, or the operations of a single functional unit may be performed by multiple physical components. The order of processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, the base station 10 and terminal 20 have been described using functional block diagrams, but such devices may be realized by hardware, software, or a combination thereof. The software operated by the processor of the base station 10 in accordance with an embodiment of the present invention and the software operated by the processor of the terminal 20 in accordance with an embodiment of the present invention may each be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or any other suitable storage medium.

[0097] 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) and Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB) and 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.

[0098] Each aspect / embodiment described in the present disclosure may be applied to at least one of systems using LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (New Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-Wide Band), Bluetooth (registered trademark), or other suitable systems, and next-generation systems enhanced based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G, etc.) may also be applied.

[0099] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described herein may be rearranged 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.

[0100] In this specification, a specific operation that is described as being performed by the base station 10 may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having the base station 10, it is clear that various operations performed for communication with the terminal 20 may be performed by at least one of the base station 10 and another network node other than the base station 10 (such as, 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 10, the other network node may be a combination of multiple other network nodes (such as an MME and an S-GW).

[0101] The information, signals, etc. described in the present disclosure 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.

[0102] Input and output information may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information may be overwritten, updated, or added to. Output information may be deleted. Input information may be transmitted to another device.

[0103] In the present disclosure, the determination may be made by a value represented by one bit (0 or 1), by a Boolean value (true or false), or by a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0109] 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.

[0110] 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.

[0111] In the present disclosure, terms such as "base station (BS)," "radio base station," "base station device," "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. A base station may also be referred to by terms such as a macrocell, a small cell, a femtocell, and a picocell.

[0112] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be partitioned into multiple smaller areas, and each smaller area can also be provided with communication services by a base station subsystem (e.g., a remote radio head (RRH)). The terms "cell" or "sector" refer to part or the entire coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0113] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," and the like may be used interchangeably.

[0114] 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.

[0115] 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 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 IoT (Internet of Things) device such as a sensor.

[0116] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple terminals 20 (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the terminal 20 may be configured to have the functions of the base station 10 described above. 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.

[0117] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station may be configured to have the functions of the user terminal described above.

[0118] 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.

[0119] 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.

[0120] The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0121] 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."

[0122] 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 or that the first element must in some way precede the second element.

[0123] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0124] 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.

[0125] 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.

[0126] 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, specific windowing operations performed by the transceiver in the time domain, etc.

[0127] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol) in the time domain. A slot may be a time unit based on numerology.

[0128] 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.

[0129] 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.

[0130] 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 (for example, 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.

[0131] 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 wireless resources (such as frequency bandwidth and transmission power that can be used by each terminal 20) to each terminal 20 in TTI units. Note that the definition of TTI is not limited to this.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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 greater than or equal to 1 ms.

[0136] A resource block (RB) is a resource allocation unit in the time domain and the 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 the numerology, for example, 12. The number of subcarriers included in an RB may be determined based on the numerology.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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 BWP and numbered within the BWP.

[0141] 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.

[0142] 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."

[0143] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples, and various changes may be made to 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.

[0144] 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.

[0145] 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."

[0146] 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).

[0147] 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.

[0148] This international patent application claims priority based on Japanese Patent Application No. 2021-011397, filed on January 27, 2021, the entire contents of which are incorporated herein by reference.

[0149] REFERENCE SIGNS LIST 10 Base station 110 Transmitter 120 Receiver 130 Setting unit 140 Controller 20 Terminal 210 Transmitter 220 Receiver 230 Setting unit 240 Controller 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device

Claims

[

1. ] A receiving unit that receives RRC (Radio Resource Control) signaling, A control unit that determines a set of entries for determining a channel access mechanism based on a specific frequency band and the RRC signaling, having The receiving unit receives DCI (Downlink Control Information) that designates an entry within the set of entries, The control unit determines a channel access mechanism using the parameters of the entry designated in the set of entries by the DCI, a terminal. [

2. ] The receiving unit performs sensing in a fixed period of 5 microseconds based on the channel access mechanism, The terminal according to claim 1. [

3. ] A communication system having a terminal and a base station, The terminal A receiving unit that receives RRC (Radio Resource Control) signaling from the base station, A control unit that determines a set of entries for determining a channel access mechanism based on a specific frequency band and the RRC signaling having The receiving unit receives DCI (Downlink Control Information) that designates an entry within the set of entries from the base station, The control unit determines a channel access mechanism using the parameters of the entry designated in the set of entries by the DCI, The base station having a transmitting unit that transmits the RRC signaling and the DCI to the terminal, a communication system. [

4. ] A procedure for receiving RRC (Radio Resource Control) signaling, A procedure for determining a set of entries for determining a channel access mechanism based on a specific frequency band and the RRC signaling, A procedure for receiving DCI (Downlink Control Information) that designates an entry within the set of entries, A procedure for determining a channel access mechanism using the parameters of the entry designated in the set of entries by the DCI, A communication method executed by a terminal.