Transmitting node and communication method

Abstract

This transmission node comprises: a reception unit that executes listen before talk (LBT) in a time section immediately before a signal is transmitted; a transmission unit that transmits the signal if reception power is less than a threshold value in the time section; and a control unit that changes, when a plurality of signals are to be transmitted, between control regarding LBT for a signal to be transmitted at the initial time and control regarding LBT for signals to be transmitted at times other than the initial time.

Description

[Technical Field]

[0001] The present invention relates to a transmitting node and a communication method in a wireless communication system. [Background technology]

[0002] The 3GPP (3rd Generation Partnership Project) is currently studying a wireless communication system called 5G or NR (New Radio) (hereinafter, this wireless communication system will be referred to as "NR") in order to achieve a larger system capacity, a higher data transmission speed, and a lower latency in wireless sections. In 5G, various wireless technologies and network architectures are being studied to meet the requirements of achieving a throughput of 10 Gbps or more while keeping the latency in wireless sections to 1 ms or less (for example, Non-Patent Document 1).

[0003] Furthermore, studies on 6G have begun as the next-generation wireless communication system after 5G, and it is expected to achieve wireless quality that exceeds that of 5G. For example, studies are underway for 6G to achieve even higher capacity, the use of new frequency bands, even lower latency, even higher reliability, and the expansion of coverage to new areas (high altitude, sea, and space) (for example, Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.300 V16.3.0 (2020-09) [Non-patent document 2] NTT Docomo White Paper: 5G Advancements and 6G (2020-01) Summary of the Invention [Problem to be solved by the invention]

[0005] 6G is expected to use even higher frequencies than conventional ones in order to further improve communication speed, capacity, reliability, and latency performance. When using such high frequencies, a wider bandwidth is available, and radio waves have the characteristics of high directivity and low frequency selectivity. In addition, it has the characteristics of large Doppler shift and path loss.

[0006] Due to the characteristics of the frequency bands that utilize these high frequencies, control rules that differ from conventional cell design or base station scheduling techniques may be more desirable from the perspective of network performance.

[0007] The present invention has been made in view of the above points, and an object of the present invention is to improve network performance in a wireless communication system. [Means for solving the problem]

[0008] According to the disclosed technology, a receiver performs LBT (Listen Before Talk) in a time interval immediately before transmitting a signal, a transmitter transmits a signal if the received power in the time interval is less than a threshold, and a controller changes the control of the LBT for the signal to be transmitted initially and the control of the LBT for signals to be transmitted other than the first when transmitting multiple signals, and the controller changes the control of the LBT for the signal to be transmitted again after the LBT has failed and is successful, and transmits a transmission signal different from the one used when the LBT failed. When the LBT is successful, the transmitter adds a preamble signal to the transmission signal if there is no frame synchronization and transmits the signal, and when there is frame synchronization, transmits the signal without adding a preamble. A sending node is provided. [Effects of the Invention]

[0009] The disclosed technology provides a technology for improving reliability when repeated transmission is performed in a wireless communication system. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example (1) of a wireless communication system according to an embodiment of the present invention. [Figure 2]FIG. 2 is a diagram illustrating an example (2) of a wireless communication system according to an embodiment of the present invention. [Figure 3] FIG. 10 is a diagram illustrating an example of scheduling. [Figure 4] FIG. 1 is a diagram showing an example (1) of transmission and reception in an embodiment of the present invention. [Figure 5] FIG. 10 is a diagram showing an example (2) of transmission and reception in the embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing an example (3) of transmission and reception in the embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing an example (4) of transmission and reception in the embodiment of the present invention. [Figure 8] 2 is a diagram illustrating an example of a functional configuration of a base station 10 according to an embodiment of the present invention. [Figure 9] FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal 20 according to the embodiment of the present invention. [Figure 10] 2 is a diagram illustrating an example of a hardware configuration of a base station 10 or a terminal 20 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] In operation of the wireless communication system according to the embodiment of the present invention, an existing technology may be used as appropriate, such as, but not limited to, the existing NR or LTE.

[0013] Fig. 1 is a diagram illustrating an example (1) 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.

[0014] 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, and the time domain may be defined by the number of OFDM symbols, and the frequency domain may be defined by the number of subcarriers or the number of resource blocks. Furthermore, a TTI (Transmission Time Interval) in the time domain may be a slot, or a TTI may be a subframe.

[0015] Base station 10 is capable of performing carrier aggregation, which aggregates multiple cells (multiple CCs (component carriers)) to communicate with terminal 20. In carrier aggregation, one PCell (primary cell) and one or more SCells (secondary cells) are used.

[0016] The base station 10 transmits a synchronization signal, system information, and the like to the terminal 20. The synchronization signal is, for example, NR-PSS and NR-SSS. The system information is transmitted, for example, on the NR-PBCH or PDSCH, and is also called broadcast information. As shown in FIG. 1 , the base station 10 transmits control signals or data to the terminal 20 on the DL (Downlink) and receives control signals or data from the terminal 20 on the UL (Uplink). Note that, here, what is transmitted on a control channel such as the PUCCH or PDCCH is called a control signal, and what is transmitted on a shared channel such as the PUSCH or PDSCH is called data, but these names are merely examples.

[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 may be referred to as a UE, and the base station 10 may be referred to as a gNB.

[0018] Terminal 20 is capable of performing carrier aggregation, which aggregates multiple cells (multiple CCs (component carriers)) to communicate with base station 10. In carrier aggregation, one PCell (primary cell) and one or more SCells (secondary cells) are used. Also, a PUCCH-SCell having a PUCCH may be used.

[0019] Fig. 2 is a diagram illustrating an example (2) of a wireless communication system according to an embodiment of the present invention. Fig. 2 shows a configuration example of a wireless communication system in which DC (Dual connectivity) is implemented. As shown in Fig. 2, a base station 10A serving as an MN (Master Node) and a base station 10B serving as an SN (Secondary Node) are provided. The base station 10A and the base station 10B are each connected to a core network. The terminal 20 can communicate with both the base station 10A and the base station 10B.

[0020] A cell group provided by base station 10A, which is an MN, is called an MCG (Master Cell Group), and a cell group provided by base station 10B, which is an SN, is called an SCG (Secondary Cell Group). In addition, in a DC, an MCG is composed of one PCell and one or more SCells, and an SCG is composed of one PSCell (Primary SCG Cell) and one or more SCells.

[0021] DC may be a communication method using two communication standards, and any combination of communication standards may be used. For example, the combination may be NR and 6G standards, or LTE and 6G standards. DC may also be a communication method using three or more communication standards, and may be called by a name other than DC.

[0022] The processing operations in this embodiment may be performed in the system configuration shown in FIG. 1, in the system configuration shown in FIG. 2, or in a system configuration other than these.

[0023] 6G is expected to use even higher frequencies than conventional ones in order to further improve communication speed, capacity, reliability, and latency performance. When using such high frequencies, a wide bandwidth is available, and radio waves have the characteristics of high directivity and low frequency selectivity. In addition, 6G is characterized by large Doppler shift and path loss.

[0024] Due to the characteristics of the frequency bands using these higher frequencies, control rules different from conventional cell design or base station scheduling techniques may be more desirable from the perspective of network performance. For example, it is assumed that collision avoidance and inter-cell interference reduction between DL-DL, DL-UL, and UL-UL are less necessary than in conventional lower frequencies.

[0025] FIG. 3 is a diagram illustrating an example of scheduling. In the example illustrated in FIG. 3, beamforming by the base station 10 is realized in an analog manner, and scheduling is performed for each beam using time division multiplexing (TDM). As illustrated in FIG. 3, beam #1 and beam #2 are multiplexed using TDM. In the example illustrated in FIG. 3, the base station 10 performs scheduling using TDM for terminals 20A and 20B that use beam #1 and terminal 20C that use beam #2. If the base station 10 explicitly or implicitly notifies the terminal 20 of the timing at which DL transmission and UL reception will be performed using each beam, the terminal 20 may perform DL reception and UL transmission only at the timing when the beam used by the terminal 20 is used. Furthermore, if the base station 10 explicitly or implicitly notifies the terminal 20 of the timing at which DL reception and UL transmission will be performed by the terminal 20, the base station 10 may perform DL transmission and UL reception using the beam used for communication with the terminal 20 only at the timing.

[0026] As control rules that do not depend on scheduling, for example, the following control rules A) and B) can be considered.

[0027] Control rule A) The transmitting device transmits signals at any timing free from both the base station 10 and the terminal 20. The receiving device must detect signals at all timings at which both the base station 10 and the terminal 20 can receive the signals. If a collision of resources used for transmission occurs, the collision is treated as equivalent to a decoding error, and retransmission by feedback may be performed. In frequency bands that use higher frequencies than conventional, the beams are very narrow and the area is small, so the number of terminals 20 present within a certain beam is very small, and even if scheduling is not performed by the base station 10, the probability of collision of resources used for transmission is expected to be low.

[0028] Control rule B) The transmitting device acquires the right to transmit from both the base station 10 and the terminal 20 and transmits a signal. That is, the base station 10 and the terminal 20 transmit a signal after performing intra-system LBT (Listen before talk). The receiving device must detect signals at all times when they can be received by both the base station 10 and the terminal 20. Collisions of resources used for transmission are avoided by intra-system LBT. In frequency bands that use higher frequencies than conventional ones, the probability of resource collisions is low. In addition, control rule B can detect resource collisions that rarely occur within the same beam or due to inter-cell interference in advance and operate to avoid collisions.

[0029] Cases with and without frame synchronization are possible for both control rule A and control rule B. Hereinafter, the control rule with frame synchronization will be referred to as control rule A1 or control rule B1, and the control rule without frame synchronization will be referred to as control rule A2 or control rule B2.

[0030] For the above control rules A1, A2, B1, and B2, it is necessary to consider the transmission procedures and signal detection procedures. Also, for the above control rules B1 and B2, it is necessary to consider intra-system LBT. As elements of intra-system LBT, it is necessary to consider the transmittable time, semi-static transmission without LBT, and avoidance of frequency resource collisions. Also, for the above control rules A2 and B2, it is necessary to consider the preamble. Also, for the above control rules A1 and B1, it is necessary to consider blind detection of control signals.

[0031] Fig. 4 is a diagram showing an example (1) of transmission and reception in an embodiment of the present invention. The procedure according to the control rule A1 will be described with reference to Fig. 4. In the control rule A1, the following operations 1)-4) may be executed.

[0032] 1) A transmitting node may transmit a signal at a predetermined transmission timing. The transmission signal may be composed of at least one of a data signal, a control signal, and a reference signal. The predetermined transmission timing may be determined by the transmitting node based on a frame synchronized between the transmitting and receiving nodes.

[0033] 2) When transmitting multiple signals consecutively, the transmitting node may determine the timing of transmissions other than the first transmission based on the signal transmitted immediately before. For example, the transmission timing and transmission duration of transmissions other than the first transmission may be instructed by the receiving node to the transmitting node or may be set in advance, or may be notified to the receiving node or may be set in advance. For example, the transmission timing of transmissions other than the first transmission may be x symbols after the end of the immediately previous transmitted signal, y slots after the end of the immediately previous transmitted signal, z frames after the end of the immediately previous transmitted signal, or a combination of x, y, and z. For example, the transmission duration of transmissions other than the first transmission may be L symbols long starting from the xth symbol per slot.

[0034] In Figure 4, assuming that the first transmission is performed in slot #0, the transmission in slot #1 is performed one symbol after the end of the signal transmitted immediately before, and the transmission timing and transmission time length are 7 symbols long from the 0th symbol of the slot.

[0035] 3) The receiving node may perform blind detection of the control signal. The resources or detection opportunities of the control signal (e.g., CORESET (Control resource set) or search space) may be specified in the specifications, or may be set or notified by the transmitting node. For example, in FIG. 4, the receiving node performs blind detection on the control signal transmitted in the first two symbols of the slot.

[0036] 4) When the receiving node detects a control signal, the receiving node may demodulate the data signal. The receiving node may identify resources for the data and / or reference signal based on the detection result of the control signal. For example, in FIG. 4, when the receiving node detects a control signal transmitted in the first two symbols of a slot, the receiving node may demodulate the subsequent data signal and / or reference signal.

[0037] The correspondence between transmitting and receiving nodes is as follows: In the downlink, the transmitting node is the base station 10 and the receiving node is the terminal 20. In the uplink, the transmitting node is the terminal 20 and the receiving node is the base station 10. In the sidelink, the transmitting node is the terminal 20 and the receiving node is the terminal 20.

[0038] Fig. 5 is a diagram showing an example (2) of transmission and reception in an embodiment of the present invention. The procedure according to the control rule A2 will be described with reference to Fig. 5. In the control rule A2, the following operations 1)-4) may be executed.

[0039] 1) As shown in Fig. 5, a transmitting node may add a preamble signal to a transmission signal and transmit the signal. The transmission signal may be composed of at least one of a data signal, a control signal, and a reference signal. The transmitting node may start transmission at any timing.

[0040] 2) When a transmitting node transmits multiple signals consecutively, if the gap between the transmitted signals is equal to or less than a predetermined value, the transmitting node may not add a preamble signal to the signals other than the first transmission. The predetermined value may be a threshold value. The timing of transmitting a signal other than the first transmission may be determined based on the immediately preceding transmitted signal. For example, the transmission of the next signal may start X milliseconds after the end of the immediately preceding transmitted signal.

[0041] 3) The receiving node may perform detection of the preamble signal, and may determine that the preamble has been detected when the received power of the preamble signal is equal to or exceeds a predetermined value.

[0042] 4) When the receiving node detects the preamble signal, it may perform demodulation of the transmitted signal. The receiving node may identify resources for the transmitted signal based on the detection result of the preamble signal. The receiving node may identify resources or detection opportunities (e.g., CORESET or search space) for the control signal based on the detection result of the preamble signal, and perform blind detection of the control signal. Furthermore, when the receiving node detects the control signal, it may perform demodulation of the data signal. The receiving node may identify resources for the data and / or reference signals from the detection result of the control signal.

[0043] Fig. 6 is a diagram showing an example (3) of transmission and reception in an embodiment of the present invention. The procedure according to the control rule B1 will be described with reference to Fig. 6. In the control rule B1, the following operations 1)-4) may be executed.

[0044] 1) A transmitting node may transmit a transmission signal when the LBT is successful at a predetermined transmission timing. For example, as shown in FIG. 6, the LBT may be performed immediately before the slot in which the signal is transmitted. The transmission signal may consist of at least one of a data signal, a control signal, and a reference signal. The predetermined transmission timing may be determined based on a frame synchronized between the transmitting and receiving nodes. The LBT may perform power detection in a predetermined time interval immediately before transmitting the transmission signal, and determine that the LBT is successful when the received power is equal to or less than a predetermined value. The predetermined value may be a threshold value. If the LBT fails, the LBT may be performed again immediately before the predetermined transmission timing. Alternatively, the timing for repeatedly performing the LBT until the LBT is successful may be specified in the specifications, or may be set or notified in advance by the receiving node. Note that if the transmitting node performs the LBT again and is successful, it may transmit the same transmission signal as when the LBT failed, or it may transmit a transmission signal different from the transmission signal when the LBT failed.

[0045] 2) When continuously transmitting multiple transmission signals, the transmitting node may not perform LBT on transmissions other than the initial transmission if the gap between the transmission signals is equal to or less than a predetermined value. In other words, if the gap between a transmitted signal and a next transmitted signal is equal to or less than a predetermined value, the transmitting node may transmit the next transmitted signal without performing LBT. The predetermined value may be a threshold. When continuously transmitting multiple transmission signals, if the LBT is successful, the transmitting node may transmit the next transmitted signal without performing LBT for a predetermined period. When continuously transmitting multiple transmission signals, the transmission timing of signals other than the initial transmission may be determined based on the immediately preceding transmission signal. When continuously transmitting multiple transmission signals, the transmission timing and transmission time of signals other than the initial transmission may be instructed to the transmitting node or may be set in advance, or may be notified to the receiving node or may be set in advance. For example, the transmission timing of transmissions other than the initial transmission may be x symbols after the end of the immediately preceding transmission signal, y slots after the end of the immediately preceding transmission signal, z frames after the end of the immediately preceding transmission signal, or a combination of x, y, and z. For example, the transmission time length of a transmission other than the initial transmission may be L symbol lengths from the xth symbol per slot.

[0046] 3) The receiving node may perform blind detection of the control signal. The resource or detection opportunity (e.g., CORESET or search space) of the control signal may be specified in the specification, or may be set or notified by the transmitting node. For example, in FIG. 6, the receiving node performs blind detection on the control signal transmitted in the first two symbols of the slot.

[0047] 4) When the receiving node detects a control signal, the receiving node may demodulate the data signal. The receiving node may identify resources for the data and / or reference signal based on the detection result of the control signal. For example, in FIG. 6, when the receiving node detects a control signal transmitted in the first two symbols of a slot, the receiving node may demodulate the subsequent data signal and / or reference signal.

[0048] Fig. 7 is a diagram showing an example (4) of transmission and reception in an embodiment of the present invention. The procedure according to the control rule B2 will be described with reference to Fig. 7. In the control rule B2, the following operations 1)-4) may be executed.

[0049] 1) When the LBT is successful, the transmitting node may add a preamble signal to the transmission signal and perform transmission. For example, as shown in FIG. 7, the LBT may be performed immediately before transmitting the preamble signal. The transmission signal may consist of at least one of a data signal, a control signal, and a reference signal. The transmitting node may start the LBT and transmission at any timing. The LBT may perform power detection in a predetermined time interval immediately before transmitting the preamble signal and determine that the LBT is successful when the received power is equal to or less than a predetermined value. The predetermined value may be a threshold value. If the LBT fails, the LBT may be performed again immediately before any transmission timing. Alternatively, the timing for repeatedly performing the LBT until the LBT is successful may be specified in the specifications, or may be set or notified in advance by the receiving node. Note that, if the transmitting node performs the LBT again and is successful, it may transmit the same transmission signal as when the LBT failed, or it may transmit a transmission signal different from the transmission signal when the LBT failed.

[0050] 2) When continuously transmitting multiple signals, if the gap between the transmission signals is equal to or less than a predetermined value, the transmitting node may not add a preamble signal to transmissions other than the first transmission. The predetermined value may be a threshold. When continuously transmitting multiple signals, if the gap between the transmission signals is equal to or less than a predetermined value, the transmitting node may not perform LBT on transmissions other than the first transmission. The predetermined value may be a threshold. When continuously transmitting multiple transmission signals, if the LBT is successful, the transmitting node may continue transmission without performing LBT for a predetermined period. When continuously transmitting multiple transmission signals, the transmission timing of signals other than the first transmission may be determined based on the immediately preceding transmission signal. For example, transmission of the next signal may start X milliseconds after the end of the immediately preceding transmission signal.

[0051] 3) The receiving node may perform detection of the preamble signal, and may determine that the preamble has been detected when the received power of the preamble signal is equal to or exceeds a predetermined value.

[0052] 4) When the receiving node detects the preamble signal, it may perform demodulation of the transmitted signal. The receiving node may identify resources for the transmitted signal based on the detection result of the preamble signal. The receiving node may identify resources or detection opportunities (e.g., CORESET or search space) for the control signal based on the detection result of the preamble signal, and perform blind detection of the control signal. Furthermore, when the receiving node detects the control signal, it may perform demodulation of the data signal. The receiving node may identify resources for the data and / or reference signals from the detection result of the control signal.

[0053] According to the above-described embodiment, when collision avoidance between DL-DL, DL-UL, and UL-UL and interference reduction between cells are not as necessary as in the conventional low frequencies, the base station 10 or the terminal 20 can start signal transmission at any timing or at the timing when the transmission right is acquired by LBT, regardless of scheduling by the base station 10.

[0054] That is, in a wireless communication system, network performance can be improved.

[0055] (Device configuration) Next, a description will be given of an example of the functional configuration of the base station 10 and the terminal 20 that execute the processes and operations described above. The base station 10 and the terminal 20 include functions for executing the above-described embodiments. However, the base station 10 and the terminal 20 may each include only the functions proposed in any of the embodiments.

[0056] <Base station 10> Fig. 8 is a diagram showing an example of the functional configuration of the base station 10. As shown in Fig. 8, 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 Fig. 8 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. The transmitting unit 110 and the receiving unit 120 may be called a communication unit.

[0057] The transmitter 110 has a function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The receiver 120 has a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of a higher layer from the received signal. The transmitter 110 also has a function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, DL data, etc. to the terminal 20. The transmitter 110 also transmits the setting information, etc., described in the embodiments.

[0058] The setting unit 130 stores preset setting information and various setting information to be transmitted to the terminal 20 in a storage device, and reads out the information from the storage device as needed. The control unit 140 controls the entire base station 10, including, for example, control related to signal transmission and reception and control related to LBT. Note that the functional unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and the functional unit related to signal reception in the control unit 140 may be included in the receiving unit 120. Furthermore, the transmitting unit 110 and the receiving unit 120 may be called a transmitter and a receiver, respectively.

[0059] <Terminal 20> Fig. 9 is a diagram showing an example of the functional configuration of the terminal 20. As shown in Fig. 9, the 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. 9 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. The transmitting unit 210 and the receiving unit 220 may be called a communication unit.

[0060] The transmitter 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiver 220 receives various signals wirelessly and acquires higher layer signals from the received physical layer signals. The transmitter 210 also transmits HARQ-ACK, and the receiver 220 receives the setting information and the like described in the embodiments.

[0061] The setting unit 230 stores various setting information received from the base station 10 by the receiving unit 220 in a storage device, and reads it out from the storage device as needed. The setting unit 230 also stores setting information that is set in advance. The control unit 240 performs overall control of the terminal 20, including control related to signal transmission and reception and control related to LBT. Note that 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. The transmitting unit 210 and the receiving unit 220 may also be called a transmitter and a receiver, respectively.

[0062] (Hardware configuration) The block diagrams (FIGS. 8 and 9) 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 connected directly or indirectly (for example, by wire, wirelessly, etc.) and these multiple devices. The functional block may also be realized by combining the single device or the multiple devices with software.

[0063] 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, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocation, 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.

[0064] 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. 10 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.

[0065] In the following description, the term "apparatus" can be read 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.

[0066] Each function in the base station 10 and the terminal 20 is realized by loading predetermined 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.

[0067] 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.

[0068] Furthermore, the processor 1001 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. 8 may be implemented by a control program stored in the storage device 1002 and executed by the processor 1001. Furthermore, for example, the control unit 240 of the terminal 20 shown in FIG. 9 may be implemented by a control program stored in the storage device 1002 and executed by 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 be transmitted from a network via a telecommunications line.

[0069] 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 ROM (EPROM), an electrically erasable programmable ROM (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.

[0070] 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 disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. The above-mentioned storage medium may be, for example, a database, a server, or other suitable medium including at least one of the storage device 1002 and the secondary storage device 1003.

[0071] 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, or a communication module. 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.

[0072] 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 performs output to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0073] 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.

[0074] Furthermore, base station 10 and 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, processor 1001 may be implemented using at least one of these pieces of hardware.

[0075] (Summary of the embodiment) As described above, according to an embodiment of the present invention, a transmitting node is provided that has a receiving unit that performs LBT (Listen before talk) in a time interval immediately before transmitting a signal, a transmitting unit that transmits a signal if the received power in that time interval is below a threshold, and a control unit that, when transmitting multiple signals, changes the control related to the LBT for the signal that is transmitted for the first time and the control related to the LBT for signals that are transmitted other than the first time.

[0076] With the above configuration, when collision avoidance between DL-DL, DL-UL, and UL-UL and interference reduction between cells are not as necessary as in the conventional low frequencies, the base station 10 or the terminal 20 can start signal transmission at any timing or at the timing when the transmission right is acquired by LBT, regardless of scheduling by the base station 10. That is, in the wireless communication system, it is possible to improve the network performance.

[0077] When transmitting multiple signals, if the received power of one of the multiple signals is below a threshold in a time interval immediately before transmitting the other signal, the control unit may control the transmission of the multiple signals without performing LBT for a certain period of time. With this configuration, the base station 10 or the terminal 20 can start transmitting signals for a certain period of time after acquiring the transmission right through LBT.

[0078] When transmitting multiple signals, if the gap between a transmitted signal and the next signal to be transmitted is less than a threshold, the control unit may control the transmission of the next signal to be transmitted without performing LBT. With this configuration, the base station 10 or the terminal 20 can start transmitting the next signal if the transmission of the signal following the signal for which the transmission right was obtained by LBT is imminent.

[0079] When transmitting multiple signals, if the gap between a transmitted signal and the next signal to be transmitted among the multiple signals is less than a threshold, the transmitter may transmit the next signal to be transmitted without transmitting a preamble. With this configuration, the base station 10 or the terminal 20 can save power by not transmitting a preamble for the next signal if the transmission of the next signal following the signal for which the transmission right was obtained by LBT is imminent.

[0080] The receiver may repeatedly execute the LBT at a predetermined timing when the received power exceeds a threshold during the time period. With this configuration, the base station 10 or the terminal 20 can acquire the right to transmit by repeating the LBT at a specified timing even if the LBT fails.

[0081] Furthermore, according to an embodiment of the present invention, a communication method is provided in which a transmitting node executes a receiving procedure in which LBT (Listen before talk) is performed in a time interval immediately before transmitting a signal, a transmitting procedure in which a signal is transmitted if the received power in the time interval is less than a threshold, and a control procedure in which, when transmitting multiple signals, the control related to the LBT for the signal transmitted for the first time and the control related to the LBT for signals transmitted other than the first time are changed.

[0082] With the above configuration, when collision avoidance between DL-DL, DL-UL, and UL-UL and interference reduction between cells are not as necessary as in the conventional low frequencies, the base station 10 or the terminal 20 can start signal transmission at any timing or at the timing when the transmission right is acquired by LBT, regardless of scheduling by the base station 10. That is, in the wireless communication system, it is possible to improve the network performance.

[0083] (Supplementary explanation of the embodiment) 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; two or more items may be combined as needed, and items described in one item may apply to items described in another item (unless inconsistent). The boundaries between functional units or processing units in the functional block diagram do not necessarily correspond to the 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 the 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. However, such devices may be implemented using 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, registers, hard disk (HDD), removable disk, CD-ROM, database, server or any other suitable storage medium.

[0084] 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., Radio Resource Control (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.

[0085] 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-Wideband), Bluetooth (registered trademark), or other appropriate systems, and next-generation systems extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G, etc.) may also be applied.

[0086] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described herein 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.

[0087] 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).

[0088] The information or signals 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.

[0089] 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 sent to another device.

[0090] In the present disclosure, 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).

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0096] 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.

[0097] 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.

[0098] In this disclosure, terms such as "base station (BS)," "radio base station," "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.

[0099] 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 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 (RRH: Remote Radio Head)). The term "cell" or "sector" refers to a part or the entire coverage area of a base station and / or base station subsystem that provides communication service within this coverage.

[0100] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0101] 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.

[0102] 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, or the mobile body itself. 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.

[0103] 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 a plurality of terminals 20 (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0108] 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."

[0109] 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.

[0110] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0111] 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.

[0112] 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.

[0113] Numerology may be communication parameters that apply 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 the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] The BWP may include a BWP for UL (UL BWP) and a BWP for DL (DL BWP). One or more BWPs may be set for the terminal 20 within one carrier.

[0129] At least one of the configured BWPs may be active, and the terminal 20 may not expect to transmit or receive a predetermined signal / channel outside the active BWP. Note that the terms "cell," "carrier," and the like in this disclosure may be read as "BWP."

[0130] 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.

[0131] 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.

[0132] 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."

[0133] 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).

[0134] In the present disclosure, the base station 10 and the terminal 20 are examples of a transmitting node.

[0135] 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]

[0136] 10 base station 110 Transmitter 120 Receiver 130 Setting section 140 Control Unit 20 terminals 210 Transmitter 220 Receiving unit 230 Setting Section 240 Control Unit 30 Core Network 1001 processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication equipment 1005 Input Device 1006 Output Device

Claims

1. a receiving unit that executes LBT (Listen before talk) in a time interval immediately before transmitting a signal; a transmitter that transmits a signal when the received power is less than a threshold value in the time interval; When transmitting a plurality of signals, a control unit is provided which changes the control relating to the LBT for the signal to be transmitted for the first time and the control relating to the LBT for the signals to be transmitted other than the first time, The control unit transmits a transmission signal different from that transmitted when the LBT failed if the LBT is performed again and succeeds after the LBT failed, A transmitting node in which, when LBT is successful, the transmitting unit adds a preamble signal to the transmission signal if there is no frame synchronization and transmits it, and when there is frame synchronization, the transmitting signal is transmitted without adding a preamble.

2. The control unit controls the transmitting node of claim 1 to transmit multiple signals without performing LBT for a certain period of time if the received power is less than a threshold in the time period immediately before transmitting one of the multiple signals.

3. The control unit controls the transmitting node of claim 1 to transmit the next signal without performing LBT when transmitting multiple signals and the gap between a transmitted signal and the next signal to be transmitted is less than a threshold value.

4. The transmitting node according to claim 1, wherein when transmitting a plurality of signals, if a gap between a transmitted signal among the plurality of signals and a next signal to be transmitted is less than a threshold, the transmitting unit transmits the next signal to be transmitted without transmitting a preamble.

5. The transmitting node according to claim 1 , wherein the receiving unit repeatedly executes LBT at a predetermined timing when the received power exceeds a threshold in the time period.

6. a receiving procedure in which LBT (Listen before talk) is performed in a time interval immediately before transmitting a signal; a transmission step of transmitting a signal if the received power is less than a threshold value in the time interval; When transmitting multiple signals, a control procedure for changing the control related to LBT for the signal to be transmitted initially and the control related to LBT for signals to be transmitted other than the initial signal; A procedure for transmitting a different transmission signal than that used when the LBT failed if the LBT was attempted again and succeeded; A communication method in which, when LBT is successful, the transmitting node executes a procedure of adding a preamble signal to the transmission signal if frame synchronization is not performed, and transmitting the transmission signal without adding a preamble if frame synchronization is performed.

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