Communication device, communication method, and program

Abstract

A communication device includes: a communication unit that performs radio communication; and a control unit that performs carrier sensing with a base station and performs control so that a radio signal is transmitted via a carrier designated by the base station according to a sensing result, wherein the control unit performs control so that information related to transmission of uplink control information is acquired from the base station when transmission of the uplink control information via the carrier is suppressed.

Description

Technical Field

[0001] The present disclosure relates to a communication device, a communication method, and a program. Background Art

[0002] Radio access systems and radio networks for cellular mobile communication (hereinafter also referred to as “Long Term Evolution (LTE)”, “LTE-Advanced (LTE-A)”, “LTE-Advanced Pro (LTE-A Pro)”, “New Radio (NR)”, “New Radio Access Technology (NRAT)”, “Evolved Universal Terrestrial Radio Access (EUTRA)”, or “Further EUTRA (FEUTRA)”) have been studied for the 3rd Generation Partnership Project (3GPP). Note that, in the following description, LTE includes LTE-A, LTE-A Pro, and EUTRA, and NR includes NRAT and FEUTRA. In the case of LTE, a base station device (base station) is also referred to as an evolved Node B (eNodeB); in the case of NR, a base station device (base station) is also referred to as a gNodeB; and, in the case of LTE and NR, a terminal device (mobile station, mobile station device, and terminal) is also referred to as a user equipment (UE). LTE and NR are cellular communication systems in which a plurality of regions covered by a base station device are arranged in the form of cells. A single base station device can also manage a plurality of cells.

[0003] NR is a radio access technology (RAT) that is different from LTE and represents the next-generation radio access system with respect to LTE. NR is an access technology that enables compatibility with various use cases, including enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC). NR is being studied with the goal of establishing a technical framework to handle usage scenarios, requirements, and layout scenarios for such use cases.

[0004] The application of a radio access system based on cellular communication is being examined for unlicensed bands and licensed shared bands. In such unlicensed bands, coexistence with other nodes and radio systems is considered important, and for LTE, NR, and other such radio access systems, functions such as listen-before-talk (LBT) in which channel sensing is performed before transmission and discontinuous transmission are required. Details of an NR-based radio access system in an unlicensed band are disclosed in Non-Patent Document 1. Note that unlicensed bands are, for example, the 2.4-GHz band, the 5-GHz band, and the 6-GHz band. Licensed shared bands are, for example, the 3.5-GHz band and the 37-GHz band. Non-Patent Document 2 also discloses examples of technologies related to the application of a radio access system in an unlicensed band.

[0005] Citation List

[0006] Non-Patent Literature

[0007] Non-Patent Literature 1: RP-172021, "Study on NR-based Access to Unlicensed Spectrum", 3GPP TSG RAN Meeting #77, Sapporo, Japan, September 11 - 14, 2017.

[0008] Non-Patent Literature 2: "MulteFire Release 1.0 Technical Paper", [Online], MulteFire Alliance, [Searched on December 13, 2018], Internet <https: / / www.multefire.org / wp-content / uploads / MulteFire-Release-1.0-whitepaper_FINAL.pdf> Summary of the Invention

[0009] Technical Problem

[0010] For the fifth-generation mobile communication system (5G), implementations of NR-based radio communication using unlicensed frequency bands are also being considered. This NR-based radio communication using unlicensed frequency bands is also referred to as "NR-U". To support various use cases assumed for NR-U, for example, mechanisms involving using unlicensed frequency bands to perform synchronization signal (SS) transmission and physical channels and physical signals (such as PRACH or PUCCH) transmitted in the primary cell (PCell, PSCell) have been considered.

[0011] However, when using unlicensed frequency bands, the communication device determines whether the channel is available by performing channel sensing (LBT) before information transmission, and performs information transmission when the channel is available. In other words, in the case of using unlicensed frequency bands, depending on the LBT result, it may be difficult for the communication device to perform information transmission (and thus information transmission can be suppressed). Therefore, in the case of NR-U, it can be expected that there will be cases where uplink control information (for example, uplink control information (UCI)) is not sent from the terminal device to the base station according to channel availability. In such cases, it is also expected that radio communication resources will be unnecessarily consumed, for example, due to data retransmission, etc., and the utilization rate of the entire system resources is reduced.

[0012] Therefore, the present disclosure proposes a technology that enables radio communication using unlicensed frequency bands to be implemented in a more preferable manner.

[0013] Solution to the Problem

[0014] According to the present disclosure, there is provided a communication device including: a communication unit that performs radio communication; and a control unit that performs carrier sensing with a base station and performs control to transmit a radio signal via a carrier designated by the base station according to a sensing result, wherein the control unit performs control to obtain information related to transmission of uplink control information from the base station when transmission of the uplink control information via the carrier is suppressed.

[0015] Moreover, according to the present disclosure, there is provided a communication device including: a communication unit that performs radio communication; and a control unit that performs control to transmit a radio signal via a carrier designated for a terminal device according to a result of carrier sensing with the terminal device, wherein the control unit performs control to transmit information related to transmission of uplink control information to the terminal device when transmission of the uplink control information via the carrier by the terminal device is suppressed.

[0016] Moreover, according to the present disclosure, there is provided a communication method executed by a computer, the method including: performing radio communication; and performing carrier sensing with a base station and performing control to transmit a radio signal via a carrier designated by the base station according to a sensing result, wherein control is performed to obtain information related to transmission of uplink control information from the base station when transmission of the uplink control information via the carrier is suppressed.

[0017] Moreover, according to the present disclosure, there is provided a communication method executed by a computer, the method including: performing radio communication; and performing control to transmit a radio signal via a carrier designated for a terminal device according to a result of carrier sensing with the terminal device, wherein control is performed to transmit information related to transmission of uplink control information to the terminal device when transmission of the uplink control information via the carrier by the terminal device is suppressed.

[0018] Moreover, according to the present disclosure, there is provided a program that causes a computer to perform the following operations: performing radio communication; and performing carrier sensing with a base station and performing control to transmit a radio signal via a carrier designated by the base station according to a sensing result, wherein control is performed to obtain information related to transmission of uplink control information from the base station when transmission of the uplink control information via the carrier is suppressed.

[0019] In addition, according to the present disclosure, a program is provided that causes a computer to perform the following operations: perform radio communication; and perform control so as to transmit a radio signal via a carrier designated for a terminal device according to a result of carrier sensing with the terminal device, wherein the control is performed so that information related to transmission of uplink control information is transmitted to the terminal device in a case where transmission of the uplink control information via the carrier by the terminal device is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is an explanatory diagram illustrating an example of a schematic configuration of a system according to an embodiment of the present disclosure.

[0021] Figure 2 is a block diagram illustrating an example of a configuration of a base station according to an embodiment.

[0022] Figure 3 is a block diagram illustrating an example of a configuration of a terminal device according to an embodiment.

[0023] Figure 4 is an explanatory diagram schematically illustrating an example of a case of LBT failure.

[0024] Figure 5 is an explanatory diagram illustrating an example of a communication sequence in communication using an unlicensed band.

[0025] Figure 6 is an explanatory diagram illustrating an example of resource scheduling in a system according to an embodiment.

[0026] Figure 7 is an explanatory diagram schematically illustrating an example of a case where it is difficult to transmit information using a control channel.

[0027] Figure 8 is a block diagram illustrating a first example of a schematic configuration of an eNB.

[0028] Figure 9 is a block diagram illustrating a second example of a schematic configuration of an eNB.

[0029] Figure 10 is a block diagram illustrating an example of a schematic configuration of a smart phone.

[0030] Figure 11 is a block diagram illustrating an example of a schematic configuration of a car navigation device. DETAILED DESCRIPTION OF THE INVENTION

[0031] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that in this specification and the drawings, redundant descriptions of components having substantially the same functional configurations are omitted by assigning the same reference numerals.

[0032] Note that the description will be provided in the following order.

[0033] 1. Configuration Example

[0034] 1.1 System Configuration Example

[0035] 1.2 Base Station Configuration Example

[0036] 1.3 Terminal Device Configuration Example

[0037] 2. Research on NR-U Implementation Modes

[0038] 3. Technical Features

[0039] 4. Application Examples

[0040] 4.1 Application Examples Related to Base Stations

[0041] 4.2 Application Examples Related to Terminal Devices

[0042] 5. Conclusion

[0043] <<1. Configuration Example>>

[0044] <1.1 System Configuration Example>

[0045] First, an example of the schematic configuration of System 1 according to an embodiment of the present disclosure will be described with reference to Figure 1 FIG. Figure 1 FIG. is an explanatory diagram illustrating an example of the schematic configuration of System 1 according to an embodiment of the present disclosure. As Figure 1 shown, System 1 includes a radio communication device 100 and a terminal device 200. Herein, the terminal device 200 is also referred to as a user. The user may also be referred to as a UE. The radio communication device 100C is also referred to as a UE repeater. Herein, the UE may be a UE defined under LTE or LTE-A, and the UE repeater may be a Prose UE to network repeater according to 3GPP, but more generally, it may refer to a communication device.

[0046] (1) Radio Communication Device 100

[0047] The radio communication device 100 is a device that provides radio communication services to subordinate devices. For example, the radio communication device 100A is a base station of a cellular system (or a mobile communication system). The base station 100A performs radio communication with devices (e.g., the terminal device 200A) located within the cell 10A of the base station 100A. For example, the base station 100A sends a downlink signal to the terminal device 200A and receives an uplink signal from the terminal device 200A.

[0048] Base station 100A is logically connected to another base station using, for example, the X2 interface, and is capable of transmitting and receiving control information and the like. In addition, base station 100A is logically connected to a so-called core network (its illustration is omitted) using, for example, the S1 interface, and is capable of transmitting and receiving control information and the like. Note that the communication between these devices can be physically relayed by various devices.

[0049] Herein, Figure 1 the radio communication device 100A shown in is a macro cell base station, and cell 10A is a macro cell. Meanwhile, radio communication devices 100B and 100C are master devices that respectively operate small cells 10B and 10C. As an example, the master device 100B is a small cell base station installed as fixed. The small cell base station 100B establishes a radio backhaul link with the macro cell base station 100A, and establishes an access link with one or more terminal devices (e.g., terminal device 200B) in small cell 10B. Note that the radio communication device 100B can be a relay node defined under 3GPP. The master device 100C is a dynamic AP (access point). The dynamic AP 100C is a mobile device that dynamically operates small cell 10C. The dynamic AP 100C establishes a wireless backhaul link with the macro cell base station 100A, and establishes an access link with one or more terminal devices (e.g., terminal device 200C) in small cell 10C. The dynamic AP 100C can be, for example, a terminal device in which hardware or software capable of operating as a base station or a radio access point is installed. Small cell 10C in this case is a dynamically formed local area network (localized network / virtual cell).

[0050] Cell 10A can operate according to any radio communication system such as, for example, LTE, LTE-Advanced (LTE-A), LTE-ADVANCED PRO, GSM (registered trademark), UMTS, W-CDMA, CDMA2000, WiMAX, WiMAX2, or IEEE 802.16.

[0051] Note that a small cell is a concept that can include various types of cells smaller than a macro cell (e.g., femto cell, nano cell, pico cell, and micro cell, etc.), which are arranged to overlap or not overlap with the macro cell. In some examples, a small cell is operated by a dedicated base station. In another example, a small cell is operated because a terminal constituting the master device temporarily operates as a small cell base station. A so-called relay node can also be regarded as a form of small cell base station. The radio communication device serving as the parent station of the relay node is also called a donor base station. The donor base station can refer to a DeNB in LTE, or more generally to the parent station of a relay node.

[0052] (2) Terminal device 200

[0053] The terminal device 200 is capable of communicating in a cellular system (or a mobile communication system). The terminal device 200 performs radio communication with radio communication devices (e.g., base station 100A and master device 100B or 100C) in the cellular system. For example, the terminal device 200A receives a downlink signal from the base station 100A and transmits an uplink signal to the base station 100A.

[0054] In addition, the terminal device 200 is not limited to the so-called UE, but may also adopt so-called low-cost terminals (low-cost UEs) such as MTC terminals, enhanced MTC (eMTC) terminals, and NB-IoT terminals. In addition, infrastructure terminals such as roadside units (RSUs) and terminals such as customer premise equipment (CPE) may also be adopted.

[0055] (3) Supplementary information

[0056] Although the schematic configuration of system 1 has been described above, this technology is not limited to Figure 1 the example shown. For example, as the configuration of system 1, a configuration that does not include a master device, small cell enhancement (SCE), heterogeneous network (HetNet), MTC network, etc. may be adopted. In addition, as another example of the configuration of system 1, the master device may be connected to a small cell, and a cell subordinate to the small cell may be constructed.

[0057] <1.2 Example of base station configuration>

[0058] Next, the configuration of the base station 100 according to an embodiment of the present disclosure will be described with reference to Figure 2 FIG. is a block diagram illustrating an example of the configuration of the base station 100 according to an embodiment of the present disclosure. Referring to Figure 2 FIG., the base station 100 includes an antenna unit 110, a radio communication unit 120, a network communication unit 130, a storage unit 140, and a control unit 150. Figure 2

[0059] (1) Antenna unit 110

[0060] The antenna unit 110 radiates the signal output by the radio communication unit 120 into space as radio waves. In addition, the antenna unit 110 converts the radio waves in space into a signal and outputs the signal to the radio communication unit 120.

[0061] (2) Radio communication unit 120

[0062] The radio communication unit 120 transmits and receives signals. For example, the radio communication unit 120 transmits a downlink signal to the terminal device and receives an uplink signal from the terminal device.

[0063] (3) Network communication unit 130

[0064] The network communication unit 130 transmits and receives information. For example, the network communication unit 130 sends information to other nodes and receives information from other nodes. For example, other nodes include other base stations and core network nodes.

[0065] Note that, as mentioned previously, in the case of the system 1 according to this embodiment, the terminal device sometimes operates as a relay terminal to relay communication between a remote terminal and a base station. In this case, for example, the radio communication device 100C equivalent to the relay terminal does not need to be equipped with the network communication unit 130.

[0066] (4) Storage unit 140

[0067] The storage unit 140 temporarily or permanently stores various data and programs for operating the base station 100.

[0068] (5) Control unit 150

[0069] The control unit 150 provides various functions of the base station 100. The control unit 150 includes a communication control unit 151, an information acquisition unit 153, a determination unit 155, and a notification unit 157. Note that the control unit 150 may further include other components in addition to these components. That is, the control unit 150 may further perform other operations in addition to the operations of these components.

[0070] The communication control unit 151 performs various processes related to the control of radio communication with the terminal device 200 via the radio communication unit 120. For example, the communication control unit 151 may control the transmission of various information and data to the terminal device 200 based on the determination result of the determination unit 155 (described later) regarding whether the desired channel is available. More specifically, when it is difficult to use the target channel, the communication control unit 151 may suppress the transmission of various information and data to the terminal device 200. In addition, the communication control unit 151 may control the allocation of resources that enable the terminal device 200 to send various information and data to the base station 100. In addition, the communication control unit 151 performs various processes related to controlling communication with other nodes (such as other base stations, core network nodes, etc.) via the network communication unit 130.

[0071] The information acquisition unit 153 acquires various information from the terminal device 200 and other nodes. For example, the acquired information can be used for control such as the control of radio communication with the terminal device or the control related to connection with other nodes.

[0072] The determination unit 155 performs various determinations related to the control of radio communication with the terminal device 200 via the radio communication unit 120. For example, the determination unit 155 may determine whether the channel can be used to transmit various information and data by performing channel sensing (e.g., LBT).

[0073] The notification unit 157 notifies various information to the terminal device 200 and other nodes. As a specific example, the notification unit 157 may notify the terminal device 200 of various information that enables the terminal device 200 in the cell to perform radio communication with the base station 100. As a specific example, the notification unit 157 may notify the terminal device 200 of information related to the individual transmission and retransmission of various information and data (e.g., resource information, etc.), thereby suppressing the transmission to the base station 100 according to various conditions such as the result of channel sensing performed by the terminal device 200. In addition, as another example, the notification unit 157 may also notify the information obtained from the terminal device 200 in the cell to another node (e.g., another base station). In addition, the notification unit 157 may notify the terminal device 200 in the cell of information that enables the terminal device 200 to perform inter-terminal communication (e.g., sidelink communication) with another terminal device 200.

[0074] <1.3 Terminal Device Configuration Example>

[0075] Next, an example of the configuration of the terminal device 200 according to an embodiment of the present disclosure will be described with reference to Figure 3 FIG. is a block diagram illustrating an example of the configuration of the terminal device 200 according to an embodiment of the present disclosure. As shown in Figure 3 FIG., the terminal device 200 includes an antenna unit 210, a radio communication unit 220, a storage unit 230, and a control unit 240. Figure 3 As shown in FIG., the terminal device 200 includes an antenna unit 210, a radio communication unit 220, a storage unit 230, and a control unit 240.

[0076] (1) Antenna Unit 210

[0077] The antenna unit 210 radiates the signal output by the radio communication unit 220 into space as radio waves. In addition, the antenna unit 210 converts the radio waves in space into a signal and outputs the signal to the radio communication unit 220.

[0078] (2) Radio Communication Unit 220

[0079] The radio communication unit 220 transmits and receives signals. For example, the radio communication unit 220 receives a downlink signal from the base station and transmits an uplink signal to the base station.

[0080] In addition, in the case of the system 1 according to the present embodiment, the terminal device 200 sometimes directly communicates with another terminal device 200 without going through the base station 100. In this case, the radio communication unit 220 can send to / receive from another terminal device 200 a sidelink signal.

[0081] (3) Storage unit 230

[0082] The storage unit 230 temporarily or permanently stores programs and various data for operating the terminal device 200.

[0083] (4) Control unit 240

[0084] The control unit 240 provides various functions of the terminal device 200. For example, the control unit 240 includes a communication control unit 241, an information acquisition unit 243, a determination unit 245, and a notification unit 247. Note that the control unit 240 may further include other components in addition to these components. That is, the control unit 240 may further perform other operations in addition to the operations of these components.

[0085] The communication control unit 241 performs various processes related to the control of radio communication with the base station 100 and other terminal devices 200 via the radio communication unit 220. For example, the communication control unit 241 can control the transmission of various information and data to the base station 100 according to the determination result of the determination unit 245 (described later) on whether the desired channel is available. More specifically, when it is difficult to use the target channel, the communication control unit 241 can suppress the transmission of various information and data to the base station 100. In addition, the communication control unit 241 can suppress the scheduled transmission of various information and data to the base station 100 according to an instruction from the base station 100. In this case, the communication control unit 241 can perform control to separately transmit the suppressed various information and data at different timings.

[0086] The information acquisition unit 243 acquires various information from the base station 100 and another terminal device 200. As a specific example, in the case of suppressing the transmission of various information and data to the base station 100, the information acquisition unit 243 can acquire information related to the separate transmission and retransmission of various information and data from the base station 100.

[0087] The determination unit 245 performs various determinations related to the control of radio communication with the base station 100 via the radio communication unit 220. For example, the determination unit 245 can determine whether a channel can be used to transmit various information and data by performing channel sensing (e.g., LBT).

[0088] The notification unit 247 notifies various information to the base station 100 and another terminal device 200. As a specific example, the notification unit 247 may notify the base station 100 of information that can be used by the base station 100 to control radio communication with the terminal device 200, such as the measurement result of channel congestion degree.

[0089] <<2. Research on NR-U Implementation Modes>>

[0090] Next, after providing an overview of New Radio-Unlicensed (NR-U), technical issues of NR-U implementation modes will be examined. As mentioned above, NR-based radio communication using unlicensed bands (i.e., NR-U) is also being considered for the fifth-generation mobile communication system (5G).

[0091] With NR-U, it is assumed to support various use cases, such as not only supporting Licensed-Assisted Access (LAA) using the carrier aggregation mechanism, but also supporting dual connectivity, independent operation only on unlicensed bands, and operation combining licensed bands and unlicensed bands. Examples of the operation combining licensed bands and unlicensed bands include, for example, the following use cases: where the licensed band is used for one of the downlink (DL) carrier and the uplink (UL) carrier, and the unlicensed band is used for the other carrier (e.g., a combination of licensed DL and unlicensed UL).

[0092] To support the foregoing use cases, mechanisms for transmitting physical channels and physical signals using unlicensed bands are examined, where the physical channels and physical signals are transmitted in a primary cell (PCell, PSCell) (such as, for example, a synchronization signal (SS), a physical random access channel (PRACH), and a physical uplink control channel (PUCCH)).

[0093] Generally, when using unlicensed bands, a communication device performs Carrier Sense (LBT) before transmitting a radio signal (physical channel and / or physical signal) via a carrier (band, bandwidth, channel), and determines whether the carrier is available (e.g., makes a decision of idle or busy). When the target carrier is available (idle) (i.e., when LBT is successful), the communication device can transmit a radio signal (physical channel and / or physical signal) via the carrier. On the other hand, when it is difficult to utilize the target carrier (busy) (i.e., when LBT fails), the communication device has difficulty transmitting a radio signal via the carrier. In other words, in this case, for example, the communication device suppresses transmitting a radio signal via the carrier.

[0094] LAA can be cited as an example of a technique that utilizes an unlicensed frequency band. With LAA, since the licensed frequency band is used for communication in the primary cell, there is no need to perform carrier sensing (such as LBT) when transmitting the Physical Uplink Control Channel (PUCCH). However, in use cases such as dual connectivity and stand alone, the unlicensed frequency band can be used for primary cell uplink communication. In the case where the unlicensed frequency band is used for uplink communication in the primary cell, the following situation can be envisaged: due to LBT failure, information (such as PUCCH) that the base station 100 can use for communication control is not sent from the terminal device 200 to the base station 100.

[0095] For example, Figure 4 is an explanatory diagram outlining an example of a situation where LBT fails, and schematically illustrates a situation where the so-called hidden terminal problem may occur. More specifically, in Figure 4 the example shown, the terminal device 200 is located in cell 10A of the base station 100. An access point 100D is also installed near the terminal device 200, and the terminal device 200 is also within the communication range 10D of the access point 100D. In such a situation, for example, when the terminal device 200 performs LBT to send a PUCCH to the base station 100, LBT fails when the carrier scheduled to be used is being used by the access point 100D to send a PUCCH. In other words, in this case, the terminal device 200 determines that the carrier is busy and suppresses the transmission of the PUCCH scheduled for the base station 100.

[0096] The PUCCH is used, for example, to send acknowledgments (HARQ-ACK, HARQ bits, ACK / NACK, or A / N) corresponding to the Physical Downlink Shared Channel (PDSCH). When an acknowledgment is not sent back from the terminal device 200 using the resources specified by the base station 100, the base station 100 retransmits the PDSCH even if the PDSCH has been successfully decoded on the terminal device 200 side.

[0097] Here, reference will be made to Figures 5 to 7 an outline of an example of the processing in the case where the unlicensed frequency band is used for communication in the primary cell.

[0098] Figure 5 is an explanatory diagram illustrating an example of a communication sequence when communicating using the unlicensed frequency band, and an explanatory diagram illustrating an example of the case where the unlicensed frequency band is used for communication in the primary cell. More specifically, Figure 5 illustrates a communication sequence in the case where the base station 100 sends data to the terminal device 200 and the terminal device 200 sends back an acknowledgment (ACK) or negative acknowledgment (NACK) to the base station 100 based on the result of decoding the data. In addition, Figure 6This is an explanatory diagram showing an example of resource scheduling in the system according to this embodiment, and shows an example of the resource scheduling result in the case of implementing HARQ assuming the use of an unlicensed band. In Figure 6 In the example shown, the horizontal axis represents time, and the vertical axis represents frequency.

[0099] When the base station 100 (determination unit 155) transmits data to the terminal device 200 using an unlicensed band, it determines whether the carrier is available for data transmission by performing carrier sensing (LBT) (S101). In addition, after determining that the carrier is available, the base station 100 (communication control unit 151) transmits the target data to the terminal device 200 via the carrier (S103). As Figure 6 shown, the PDSCH is used for data transmission, for example. In addition, at this time, the base station 100 (communication control unit 151) allocates resources for the terminal device 200 to send an acknowledgment (HARQ-ACK) corresponding to the data decoding result back to the base station 100, and issues an instruction regarding the resources to the terminal device 200. For example, the physical downlink control channel (PDCCH) is used for the resource instruction.

[0100] After receiving the data from the base station 100, the terminal device 200 (communication control unit 241) decodes the data (S105). Then, the terminal device 200 (communication control unit 241) sends an acknowledgment corresponding to the data decoding result to the base station 100 that is the data transmission source. More specifically, by performing sensing (LBT) of the carrier corresponding to the resources indicated by the base station 100, the terminal device 200 (determination unit 245) determines whether the carrier can be used to send an acknowledgment to the base station 100 (S107). In addition, after determining that the carrier is available, the terminal device 200 (communication control unit 241) sends an acknowledgment (HARQ-ACK) corresponding to the data decoding result to the base station 100 via the carrier (S109). As mentioned above, for example, the PUCCH is used to send the acknowledgment.

[0101] However, when using an unlicensed band for communication in the primary cell according to NR-U, depending on the LBT result, it is sometimes difficult to send physical control channels such as PDCCH or PUCCH. For example, Figure 7 This is an explanatory diagram showing an example of a situation where it is difficult to send information using a physical control channel. More specifically, in Figure 7 the example shown, similar to Figure 6 the example shown, the resources for sending an acknowledgment (HARQ-ACK) corresponding to the data decoding result back to the base station 100 are allocated by the base station 100 to the terminal device 200. However, in Figure 7In the example shown, the LBT result of the terminal device 200 is busy, and it is difficult for the terminal device 200 to use the PUCCH to send a HARQ-ACK corresponding to the data decoding result to the base station 100. That is, in Figure 7 In the example shown, the terminal device 200 suppresses sending the HARQ-ACK back to the base station 100. In addition, since the HARQ-ACK is not sent back from the terminal device 200, it is difficult for the base station 100 to determine whether the data has been decoded by the terminal device 200, so the base station 100 retransmits the target data. Due to such retransmission of data (PDSCH), radio communication resources are consumed unnecessarily, resulting in a reduction in the utilization rate of the overall system resources.

[0102] Moreover, "MulteFire" can be cited as an example of a technology that enables the use of unlicensed bands. MulteFire makes it possible to retransmit HARQ bits corresponding to all HARQ processes, and a favorable effect of improving the overall system utilization rate can also be expected compared to the case of retransmitting the PDSCH. However, it can be foreseen that there are cases where basically unnecessary information is also sent, so it is sometimes difficult to expect to improve resource utilization in HARQ feedback.

[0103] In view of the foregoing, the present disclosure describes a technology that can use a more appropriate method to implement radio communication using unlicensed bands, particularly focusing on the case of transmitting radio signals (in other words, various information and data) using unlicensed bands according to NR-U.

[0104] <<3. Technical Features>>

[0105] Next, the technical features of the system according to an embodiment of the present disclosure will be described below. Note that although the description below focuses mainly on the example of HARQ-ACK transmission via the PUCCH as a case of communicating using an unlicensed band in the primary cell, the purpose of the application of the technology of the present disclosure is not necessarily limited. That is, the present disclosure is not limited to or restricted by the case of sending HARQ-ACK, but the technology of the present disclosure can be applied as long as it involves the case of sending information via the physical uplink control channel (PUCCH).

[0106] (Setting of Resources Related to Transmission of Suppressed HARQ Bits)

[0107] In the system according to an embodiment of the present disclosure, resources (e.g., resources for retransmission) have been set for separately transmitting HARQ bits that have not been transmitted due to LBT failure or the like (e.g., HARQ bits whose transmission has been suppressed). Therefore, by improving the utilization rate of resources by enabling HARQ bits to be transmitted separately, a favorable effect of further improving the overall system resource utilization rate can be expected. In this case, for example, the base station 100 can take the lead in performing various controls.

[0108] For example, a trigger (UCI grant) for transmitting HARQ-ACK can be sent from the base station 100 to the terminal device 200. For example, the trigger can be sent to the terminal device 200 by using downlink control information (DCI). As a specific example, the base station 100 can notify the terminal device 200 of the fact that HARQ has not been received yet. The received terminal device 200 can transmit HARQ bits that have not been transmitted previously (in other words, HARQ bits whose transmission has been suppressed previously) in addition to, for example, HARQ bits transmitted at the next HARQ feedback opportunity.

[0109] Furthermore, as another example, the base station 100 can notify the terminal device 200 of information related to resources available for HARQ feedback by associating the information with the aforementioned trigger. In this case, the terminal device 200 can use the aforementioned resources notified by the base station 100 to transmit HARQ bits that have not been transmitted previously (in other words, HARQ bits whose transmission has been suppressed previously).

[0110] Furthermore, in this case, in order to prevent discontinuous transmission (DTX) from being erroneously detected as ACK (DTX-to-ACK error detection), it is recommended to add codes related to error detection (e.g., cyclic redundancy check (CRC) of HARQ bits). For reference, in the prior art, for example, the processing is switched according to whether the number of bits of the data to be transmitted is greater than or equal to a predetermined threshold (e.g., eleven bits). As a specific example, when the number of bits of the data to be transmitted is greater than or equal to the threshold, a polar code is used. On the contrary, when the number of bits of the data to be transmitted is less than the threshold, a repetition code or a simplex code is used.

[0111] Furthermore, this is attributed to the fact that in the licensed band, when the decoding of the PDCCH on which the PUCCH is scheduled fails, DTX of the PUCCH can be generated. On the contrary, in the unlicensed band, it may be necessary to perform LBT when transmitting data. Therefore, in addition to the failure of PDCCH decoding, since the cases of non-transmission of PUCCH and LBT failure can also be expected, the frequency of DTX generation tends to be higher than that in the licensed band. Therefore, when using the unlicensed band, an improved DTX detection accuracy is expected.

[0112] Particularly, in the case where PUCCH is used to transmit HARQ bits, when the number of bits is less than a threshold (e.g., less than eleven bits in the case of NR), no CRC is added. This is due to the fact that when the number of bits is less than a predetermined number of information bits (e.g., less than eleven bits in the case of NR), the error correction capability of other coding is often higher than the error detection capability using CRC.

[0113] In view of the foregoing, as an example of a method for improving the DTX detection ability by adding CRC to HARQ bits (i.e., target data), for example, a method of adding CRC to the data even when the number of HARQ bits is less than the threshold can be cited. That is, even when the HARQ codebook size is less than eleven bits, CRC can be added to the HARQ bits. Obviously, when the number of HARQ bits is less than the threshold, it is not necessary to add CRC to the data.

[0114] In addition, as another example, when the number of HARQ bits (e.g., the HARQ codebook size of the HARQ bits) is less than the threshold, the number of bits of the data can be controlled to be greater than or equal to the threshold.

[0115] As a specific example, the terminal device 200 can also insert dummy bits into the data so that the number of HARQ bits is greater than or equal to the threshold. For example, 0, 1, or NULL (which can be 0 or 1) can be used as the dummy bits. Note that when the data has been received from the terminal device 200, the base station 100 can also ignore the dummy bits. Note that as long as the base station 100 can identify the dummy bits, there is no particular limitation on the position where the dummy bits are inserted relative to the HARQ bits. As a specific example, the dummy bits can be inserted before or after the HARQ bits.

[0116] In addition, as another example, the terminal device 200 can also perform control by making the HARQ bits redundant so that the number of bits of the data is greater than or equal to the threshold. More specifically, at least some of the HARQ bits can be made redundant by defining them in a quantity corresponding to a plurality of bits. Therefore, the beneficial effects of increasing the number of bits and improving the reliability of the HARQ bits can also be expected.

[0117] In addition, as another example, by associating additional information with the HARQ bits, the terminal device 200 can perform control so that the number of bits in a series of data including the data is greater than or equal to the threshold. For example, by associating the HARQ bits with information other than HARQ information (such as CSI information (CQI, PMI, RI, CRI, L1-RSRP, etc.)), the terminal device 200 can perform control so that the number of bits in a series of data is greater than or equal to the threshold.

[0118] Information related to the channel congestion level can also be associated with information other than HARQ information. Examples of information related to channel congestion include, for example, information such as layer 1 received signal strength indicator (L1-RSSI), channel occupancy rate, and LBT success frequency. Note that L1-RSSI indicates the RSSI measured over a short period of time. Due to such control, for example, it is possible to easily detect at the base station 100 side hidden terminals that are generally difficult to detect for the base station 100 and may affect the system. In addition, the base station 100 is also capable of selecting a channel to be used according to the channel congestion level. Moreover, improved user scheduling accuracy can also be expected.

[0119] In addition, as another example of a method that can be cited for improving the DTX detection ability, there is a method of transmitting an additional orthogonal sequence on a physical channel including HARQ bits. Possible examples of the orthogonal sequence include, for example, a physical random access channel (PRACH), a demodulation reference signal (DMRS), etc.

[0120] In addition, the terminal device 200 can take the lead in performing control for separately transmitting the untransmitted HARQ bits. In this case, for example, the terminal device 200 can transmit the untransmitted HARQ bits (in other words, the HARQ bits whose transmission has been suppressed) in association with the separately indicated uplink. In this case, for example, the PUCCH or PUSCH can be used as a resource. It is desirable for the base station 100 to preset the resource by using RRC signaling or the like.

[0121] (HARQ Codebook Size Determination)

[0122] Next, a control example related to the determination (HARQ codebook size determination) of the number of HARQ bits transmitted in the system according to an embodiment of the present disclosure (i.e., the bit size related to PUCCH transmission) will be described. Note that in the following description, for convenience, the number of HARQ bits transmitted is also referred to as the "HARQ codebook size".

[0123] For example, the HARQ codebook size can also be determined to be a fixed size. In this case, for example, the number of bits corresponding to the HARQ processing count can be ensured. A processing similar to that of MulteFire mentioned above can also be applied.

[0124] As another example, the HARQ codebook size can also be determined semi-statically (semi-static codebook size determination). In this case, the HARQ codebook size is preset. Note that, for example, the size of the HARQ codebook can also be set using RRC signaling.

[0125] As another example, the HARQ codebook size can also be determined dynamically (dynamic codebook size determination). More specifically, since it is conceivable to include multiple HARQs, the HARQ codebook size can be modified dynamically according to the situation at that time.

[0126] For example, the HARQ codebook size can be modified dynamically according to an instruction from the base station 100. In this case, the number of HARQ bits transmitted from the terminal device 200 to the base station 100 is controlled to be equal to the HARQ codebook size indicated by the base station 100. Note that possible methods for the HARQ codebook size instruction from the base station 100 include an explicit method and an implicit method.

[0127] Possible explicit methods include methods using a DL downlink allocation index (DAI) or a UL DAI. The DL DAI is the DAI included in the DCI for scheduling the PDSCH. The DL DAI can be used to map HARQ bits to HARQ processes. The UL DAI is the DAI included in the DCI for scheduling the PUSCH or PUCCH. The UL DAI is used to determine the maximum number of HARQ codebook sizes. Note that information for the extended size can also be transmitted separately from the DAI.

[0128] In the implicit method, the terminal device 200 modifies the size of the HARQ codebook after receiving a notification of other HARQ-related information. As a specific example, when the terminal device 200 has not received a notification of HARQ from the base station 100, it can extend the size of the HARQ codebook. At this time, for example, the terminal device 200 can double the size of the HARQ codebook to the size of all HARQ processes. In addition, as another example, the terminal device 200 can double the bit size to handle unreceived HARQ processes. Of course, the foregoing are merely examples, and the bit size control target and control amount can be appropriately set according to the use case.

[0129] In addition, the terminal device 200 can take the lead in dynamically modifying the HARQ codebook size. In this case, for example, the terminal device 200 is capable of determining the modified HARQ codebook size. When modifying the HARQ codebook size, for example, the terminal device 200 associates the information related to the HARQ codebook size with the HARQ bits and sends it to the base station 100. As a specific example, the terminal device 200 can use a dedicated uplink channel to perform the notification of the HARQ codebook size. More specifically, the information related to the HARQ codebook size can be notified by the terminal device 200 to the base station 100 by using the bits included in the physical channel. In addition, the terminal device 200 can perform the notification of the HARQ codebook size, for example, by associating the HARQ codebook size with a sequence related to the communication with the base station 100. As a specific example, the terminal device 200 can perform the notification of the HARQ codebook size by associating the HARQ codebook size with a channel scrambling sequence. In this case, for example, the sequence and the HARQ codebook size information are associated one-to-one. In addition, as another example, the terminal device 200 can also perform the notification of the HARQ codebook size by associating the HARQ codebook size with the DMRS sequence. In this case, for example, the sequence and the HARQ codebook size information are associated one-to-one.

[0130] (Mapping of HARQ bits to HARQ processes)

[0131] Next, the mapping of HARQ bits to HARQ processes will be described.

[0132] In the system according to an embodiment of the present disclosure, for example, the HARQ bits Figure 1 are pre-mapped one-to-one to the HARQ processes. According to the LTE and NR cases, for example, DL-DAI can also be used for the mapping. In addition, as another example, the layout of the bitmap can also be pre-associated with the HARQ processes. In this case, for example, RRC signaling can be used to establish the association rule, or the relationship between the order of the bits and the HARQ processes can be predefined in a fixed manner.

[0133] As another example, the terminal device 200 can also send both the HARQ bits and the information related to the HARQ processes to the base station 100. In other words, the terminal device 200 can send the bits indicating ACK / NACK (e.g., 1 bit) and the HARQ process index to the base station 100.

[0134] (Application to CSI feedback)

[0135] In addition, as mentioned above, the possible applications of the technology according to embodiments of the present disclosure are not limited to HARQ. As a specific example, the mechanisms mentioned above can also be applied to scheduling requests (SRs), CSI feedback, etc. In particular, the mechanisms described above can be applied to aperiodic CSI feedback.

[0136] (Scheduling Request)

[0137] In the case of NR-U, PUCCH can be used to send SRs. After the SR is sent, the terminal device 200 can start an SR prohibition timer. While the SR prohibition timer is running (in other words, until the SR prohibition timer expires), the SR transmission is suppressed. On the other hand, when the SR transmission is suppressed due to LBT failure, it is not necessary to start the SR prohibition timer. In this case, the terminal device 200 attempts to send an SR on the SR transmission resource (PUCCH resource) in the next cycle.

[0138] In addition, when the base station 100 has not performed PUSCH scheduling although the SR has been sent, the terminal device 200 can consider that an SR conflict has occurred.

[0139] After considering that an SR conflict has occurred, the terminal device 200 expects to increase the conflict window size, which is used to determine the random backoff of LBT performed before sending the next SR.

[0140] Alternatively, after considering that an SR conflict has occurred, the terminal device 200 can also apply an SR prohibition timer, which is used for the next SR transmission. The value of the SR prohibition timer can be a fixed value, a value set by the base station 100, or a value determined by the terminal device 200. In the case of a value determined by the terminal device 200, similar to the random backoff determination, a variable conflict window and a random number can also be used to make the determination. That is, the conflict window size increases according to the SR transmission count. Therefore, SR transmission conflicts can be avoided.

[0141] When the base station 100 has not performed PUSCH scheduling although the SR has been sent a predetermined number of times, the terminal device 200 initializes the random access procedure.

[0142] (Disable HARQ Transmission)

[0143] Next, the disabling of HARQ transmission will be described. Disabling HARQ transmission is a mechanism for performing control to ensure that HARQ-ACK is not sent only in a period other than COT (Channel Occupancy Time, that is, carrier dedicated time) when HARQ feedback is performed.

[0144] More specifically, during non-COT periods, since Category 4 LBT (LBT that requires random backoff using a variable-sized contention window) or Category 2 LBT (LBT that does not require random backoff) is used, the likelihood of LBT failure is high. Therefore, by applying the disabling of HARQ transmission, it is possible to expect a beneficial effect of further reducing the probability of LBT failure through execution control, such that HARQ feedback is performed only during COT periods.

[0145] Possible triggers for applying the disabling of HARQ transmission include application based on an instruction from the base station 100 to the terminal device 200 and application based on a determination by the terminal device 200.

[0146] First, an example of control in the case of applying the disabling of HARQ transmission based on an instruction from the base station 100 to the terminal device 200 will be described. In this case, a dynamic notification method and a semi-static notification method can be conceived as methods for notifying the above-mentioned instruction from the base station 100 to the terminal device 200.

[0147] Possible dynamic notification methods include an explicit notification method and an implicit notification method.

[0148] A possible explicit notification method includes a method in which, for example, a bit indicating not to transmit HARQ bits is included in the DL DCI. As a specific example, control can be performed such that when a predetermined switching bit is 1, HARQ bits are transmitted according to HARQ feedback timing information, and when the bit is 0, the HARQ feedback timing information is not utilized (e.g., ignored). Note that the relationship between the bit value and the process can also be different from the foregoing setting.

[0149] In addition, as another example, a bit for switching the state represented by information related to the timing of HARQ feedback (PDSCH to HARQ feedback timing indicator) can also be defined. As a specific example, when a predetermined switching bit is 1, the actual slot index can be used to indicate the timing, and when the bit is 0, a virtual slot index can be used to indicate the timing. Note that the virtual slot index represents a slot index in which only the slots occupied by the channel are numbered. Furthermore, the relationship between the bit value and the process can also be different from the foregoing setting.

[0150] As an implicit notification method, for example, information indicating that HARQ feedback will not be transmitted can also be included in information related to the timing of HARQ feedback (PDSCH to HARQ feedback timing indicator). As a specific example, the state of the information related to HARQ feedback timing can also be defined as a state indicating that HARQ will not be transmitted. In this case, states other than the above-mentioned state among the states of the information related to HARQ feedback timing can also indicate the slots for transmitting HARQ.

[0151] In addition, as another example, a combination of information related to HARQ feedback timing and COT length information can be used to notify information indicating that HARQ feedback will not be sent. As a specific example, if the HARQ feedback timing is within the COT period, HARQ can be sent, while if the HARQ feedback timing falls outside the COT period, HARQ transmission can be suppressed. Moreover, when the HARQ feedback timing falls outside the COT period, HARQ transmission can be performed by using the next COT.

[0152] Here, the COT length information will be described. Information related to the COT of the channel acquired by the base station 100 is notified to the terminal device 200. The base station 100 notifies information related to the COT to the terminal device 200 in a predetermined time period (e.g., all or some of the COT). Note that the information related to the COT can also be overwritten with information sent at a subsequent timing. The information related to the COT can be information shared by a terminal group. In this case, it is desirable to use a PDCCH shared by the terminal group to send information related to the COT. In addition, a bit string pattern of an orthogonal sequence of a predetermined physical signal (e.g., an initial signal) can also be used to notify information related to the COT.

[0153] In addition, possible semi-static notification methods include, for example, a method using RRC signaling. In other words, RRC signaling can be used for setting so that HARQ is not sent to the terminal device 200 in a period other than the COT period. Note that, for example, the period falling within or outside the COT period can be determined by notifying the COT length.

[0154] Next, an example of control in the case of applying HARQ transmission disabling based on the determination of the terminal device 200 will be described. More specifically, the terminal device 200 is capable of performing control so that HARQ is not sent under a predetermined condition (in other words, HARQ transmission is suppressed). For example, possible conditions when HARQ is not sent include conditions related to channel congestion. As a specific example, when the RSSI or channel occupancy rate exceeds a predetermined threshold, the terminal device 200 can suppress HARQ transmission. Accordingly, since the transmission frequency can be reduced, for example, in the case of channel congestion, the possibility of a collision occurring between transmissions from the terminal device can be reduced.

[0155] Note that HARQ that has not been transmitted (in other words, HARQ whose transmission has been suppressed) can be transmitted (retransmitted) separately by applying the same method as that for HARQ that has not been transmitted due to LBT failure.

[0156] (Supplementary information)

[0157] Examples of uplink physical channels available for HARQ feedback include msg.A in two-step RACH in addition to PUCCH and PUSCH. Msg.A is a message sent from the terminal device 200 to the base station 100 in the initial step of two-step RACH. In this case, HARQ bits are desirably transmitted in association with msg.PUSCH.

[0158] <<4. Application Examples>>

[0159] The technology according to the present disclosure can be applied to various products. For example, the base station 100 can be implemented as any type of evolved Node B (eNB) such as a macro eNB or a small eNB. A small eNB can be an eNB that covers a cell smaller than a macro cell, such as a pico eNB, a femto eNB, or a home (femto) eNB. Alternatively, the base station 100 can be implemented as another type of base station, such as a NodeB or a base transceiver station (BTS). The base station 100 can include a main entity (also referred to as base station equipment) that controls radio communication, and one or more remote radio heads (RRHs) deployed at locations different from the main entity. Additionally, various types of terminals described subsequently can be used as the base station 100 by temporarily or semi-permanently performing base station functions. Furthermore, at least some of the constituent elements of the base station 100 can be implemented in the base station equipment or a module for the base station equipment.

[0160] In addition, for example, the terminal device 2 can be implemented as a mobile terminal such as a smart phone, a tablet personal computer (PC), a notebook PC, a portable game terminal, a portable / dongle mobile router, or a digital camera, or a vehicle-mounted terminal such as a car navigation device. Furthermore, the terminal device 2 can be implemented as a terminal that performs machine-to-machine (M2M) communication (also referred to as a machine type communication (MTC) terminal). Additionally, at least some of the constituent elements of the terminal device 2 can be implemented in a module (e.g., an integrated circuit module composed of one die) built into these terminals.

[0161] <4.1 Application Examples Related to Base Stations>

[0162] (First Application Example)

[0163] Figure 8 is a block diagram showing a first example of a schematic configuration of an eNB to which the technology according to the present disclosure can be applied. The eNB 800 includes one or more antennas 810 and base station equipment 820. Each of the antennas 810 and the base station equipment 820 can be interconnected via an RF cable.

[0164] Each antenna 810 includes one or more antenna elements (e.g., multiple antenna elements constituting a MIMO antenna), and is used by the base station device 820 to transmit and receive radio signals. The eNB 800 includes multiple antennas 810 as shown in Figure 8 , and for example, the multiple antennas 810 can respectively correspond to multiple frequency bands used by the eNB 800. Note that although Figure 8 illustrates an example in which the eNB 800 includes multiple antennas 810, the eNB 800 can also include a single antenna 810.

[0165] The base station device 820 includes a controller 821, a memory 822, a network interface 823, and a radio communication interface 825.

[0166] The controller 821 can be, for example, a CPU or a DSP, and operates various functions of the host layer of the base station device 820. For example, the controller 821 generates data packets based on the data in the signals processed by the radio communication interface 825, and transmits the generated packets via the network interface 823. The controller 821 can generate bundled packets by bundling data from multiple baseband processors, and transmit the generated bundled packets. In addition, the controller 821 can also have logical functions to perform controls such as radio resource control, radio bearer control, mobility management, admission control, or scheduling. The control can also be performed in cooperation with a peripheral eNB or a core network node. The memory 822 includes RAM and ROM, and stores programs executed by the controller 821 and various control data (such as, for example, a terminal list, transmission power data, and scheduling data).

[0167] The network interface 823 is a communication interface for connecting the base station device 820 to the core network 824. The controller 821 can communicate with a core network node or another eNB via the network interface 823. In this case, the eNB 800 and the core network node or another eNB can be interconnected through a logical interface (e.g., an S1 interface or an X2 interface). The network interface 823 can be a wired communication interface or a radio communication interface for radio backhaul. In the case where the network interface 823 is a radio communication interface, the network interface 823 can use a frequency band for radio communication that is higher than the frequency band used by the radio communication interface 825.

[0168] The radio communication interface 825 supports cellular communication systems such as Long Term Evolution (LTE) or LTE-Advanced, and provides a radio connection to terminals located within the cell of the eNB 800 via the antenna 810. The radio communication interface 825 generally may include a baseband (BB) processor 826, an RF circuit 827, etc. The BB processor 826 may perform, for example, encoding / decoding, modulation / demodulation, multiplexing / demultiplexing, etc., and perform various signal processing on each layer (e.g., L1, Media Access Control (MAC), Radio Link Control (RLC), and Packet Data Convergence Protocol (PDCP)). The BB processor 826 may have some or all of the foregoing logical functions to replace the controller 821. The BB processor 826 may be a module including a memory for storing a communication control program, a processor for executing the program, and related circuits, and the functions of the BB processor 826 may be changed by updating the program. Additionally, the module may be a card or blade inserted into a slot of the base station device 820, or a chip mounted on the card or blade. Meanwhile, the RF circuit 827 may include mixers, filters, amplifiers, etc., and transmit and receive radio signals via the antenna 810.

[0169] The radio communication interface 825 includes a plurality of BB processors 826 as shown in Figure 8 and, for example, the plurality of BB processors 826 may respectively correspond to a plurality of frequency bands used by the eNB 800. Additionally, the radio communication interface 825 may include a plurality of RF circuits 827 as shown in Figure 8 and, for example, the plurality of RF circuits 827 may respectively correspond to a plurality of antenna elements. Note that although Figure 8 illustrates an example in which the radio communication interface 825 includes a plurality of BB processors 826 and a plurality of RF circuits 827, the radio communication interface 825 may include a single BB processor 826 or a single RF circuit 827.

[0170] In Figure 8 the eNB 800 shown, included in the reference Figure 2One or more of the described constituent elements in the base station 100 (e.g., at least one of the communication control unit 151, the information acquisition unit 153, the determination unit 155, and the notification unit 157) may also be installed in the radio communication interface 825. Alternatively, at least some of the constituent elements may be installed in the controller 821. As an example, the eNB 800 may incorporate a part (e.g., the BB processor 826) or all of the radio communication interface 825 and / or a module of the controller 821. One or more of the foregoing constituent elements may also be installed in a module. In this case, the module may store a program for causing a processor to function as one or more of the constituent elements (in other words, a program for causing the processor to execute the operations of the one or more constituent elements) and may execute the program. As another example, a program for causing a processor to function as one or more of the constituent elements may be installed in the eNB 800, and the radio communication interface 825 (e.g., the BB processor 826) and / or the controller 821 may execute the program. In this way, the eNB 800, the base station device 820, or the module may be provided as a device including one or more constituent elements, and a program for causing a processor to function as one or more of the constituent elements may be provided. Further, a readable recording medium on which the program is recorded may be provided.

[0171] In addition, in Figure 8 the eNB 800 shown, referring to Figure 2 the radio communication unit 120 described may also be installed in the radio communication interface 825 (e.g., the RF circuit 827). Additionally, the antenna unit 110 may be installed in the antenna 810. Further, the network communication unit 130 may be installed in the controller 821 and / or the network interface 823. Additionally, the storage unit 140 may be installed in the memory 822.

[0172] (Second application example)

[0173] Figure 9 is a block diagram showing a second example of a schematic configuration of an eNB to which the technology according to the present disclosure can be applied. The eNB 830 includes one or more antennas 840, a base station device 850, and an RRH 860. Each of the antenna 840 and the RRH 860 may be interconnected via an RF cable. Additionally, the base station device 850 and the RRH 860 may be interconnected by a high-speed line such as an optical fiber cable.

[0174] Each of the antennas 840 includes one or more antenna elements (e.g., a plurality of antenna elements constituting a MIMO antenna) and is used to transmit and receive radio signals using the RRH 860. The eNB 830 includes as Figure 9The multiple antennas 840 shown, and for example, the multiple antennas 840 may correspond to multiple frequency bands used by the eNB 830 respectively. Note that although Figure 9 An example in which the eNB 830 includes multiple antennas 840 is shown, but the eNB 830 may also include a single antenna 840.

[0175] The base station device 850 includes a controller 851, a memory 852, a network interface 853, a radio communication interface 855, and a connection interface 857. The controller 851, the memory 852, and the network interface 853 are the same as the controller 821, the memory 822, and the network interface 823 described with reference to Figure 8 the description.

[0176] The radio communication interface 855 supports any cellular communication system, such as LTE or LTE-Advanced, and provides a radio connection to a terminal located in a sector corresponding to the RRH 860 via the RRH 860 and the antenna 840. The radio communication interface 855 generally may include a BB processor 856 and the like. Except for the RF circuit 864 connected to the RRH 860 via the connection interface 857, the BB processor 856 is the same as the BB processor 826 described with reference to Figure 8 the description. The radio communication interface 855 includes multiple BB processors 856 as Figure 8 shown, and for example, the multiple BB processors 856 may correspond to multiple frequency bands used by the eNB 830 respectively. Note that although Figure 9 An example in which the radio communication interface 855 includes multiple BB processors 856 is illustrated, but the radio communication interface 855 may include a single BB processor 856.

[0177] The connection interface 857 is an interface for connecting the base station device 850 (radio communication interface 855) to the RRH 860. The connection interface 857 may be a communication module for communicating on a high-speed line connecting the base station device 850 (radio communication interface 855) to the RRH 860.

[0178] In addition, the RRH 860 includes a connection interface 861 and a radio communication interface 863.

[0179] The connection interface 861 is an interface for connecting the RRH 860 (radio communication interface 863) to the base station device 850. The connection interface 861 may be a communication module for communicating on a high-speed line.

[0180] The radio communication interface 863 transmits and receives radio signals via the antenna 840. The radio communication interface 863 generally may include an RF circuit 864, etc. The RF circuit 864 may include mixers, filters, amplifiers, etc., and transmits and receives radio signals via the antenna 840. The radio communication interface 863 may include multiple RF circuits 864 as shown in Figure 9 and, for example, the multiple RF circuits 864 may respectively correspond to multiple antenna elements. Note that although Figure 9 illustrates an example in which the radio communication interface 863 includes multiple RF circuits 864, for example, the radio communication interface 863 may include a single RF circuit 864.

[0181] In Figure 9 the eNB 830 shown, one or more constituent elements (e.g., at least one of the communication control unit 151, the information acquisition unit 153, the determination unit 155, and the notification unit 157) included in the base station 100 described in the reference Figure 2 may also be installed in the radio communication interface 855 and / or the radio communication interface 863. Alternatively, at least some of the constituent elements may be installed in the controller 851. As an example, the eNB 830 may incorporate a portion (e.g., the BB processor 856) or all of the radio communication interface 855 and / or a module of the controller 851. One or more of the foregoing constituent elements may also be installed in a module. In this case, the module may store a program for causing a processor to function as one or more constituent elements (in other words, a program for causing a processor to execute the operations of one or more constituent elements) and may execute the program. As another example, a program for causing a processor to function as one or more constituent elements may be installed in the eNB830, and the radio communication interface 855 (e.g., the BB processor 856) and / or the controller 851 may execute the program. In this way, the eNB 830, the base station device 850, or the module may be provided as a device including one or more constituent elements, and a program for causing a processor to function as one or more constituent elements may be provided. Further, a readable recording medium on which the program is recorded may be provided.

[0182] In addition, in Figure 9 the eNB 830 shown, for example, the radio communication unit 120 described in the reference Figure 2 may also be installed in the radio communication interface 863 (e.g., the RF circuit 864). Additionally, the antenna unit 110 may be installed in the antenna 840. Further, the network communication unit 130 may be installed in the controller 851 and / or the network interface 853. Additionally, the storage unit 140 may be installed in the memory 852.

[0183] <4.2 Application Examples Related to Terminal Devices>

[0184] (First Application Example)

[0185] Figure 10 It is a block diagram showing an example of a schematic configuration of a smart phone 900 to which the technology according to the present disclosure can be applied. The smart phone 900 includes a processor 901, a memory 902, a storage device 903, an external connection interface 904, a camera 906, a sensor 907, a microphone 908, an input device 909, a display device 910, a speaker 911, a radio communication interface 912, one or more antenna switches 915, one or more antennas 916, a bus 917, a battery 918, and an auxiliary controller 919.

[0186] The processor 901 can be, for example, a CPU or a system-on-chip (SoC), and controls the functions of the application layer and other layers of the smart phone 900. The memory 902 includes RAM and ROM, and stores programs and data executed by the processor 901. The storage device 903 can include a storage medium such as a semiconductor memory or a hard disk. The external connection interface 904 is an interface for connecting an externally attached device such as a memory card or a universal serial bus (USB) device to the smart phone 900.

[0187] The camera 906 includes, for example, an imaging element such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), and generates a captured image. The sensor 907 can include a sensor group that includes, for example, a positioning sensor, a gyro sensor, a geomagnetic sensor, an acceleration sensor, etc. The microphone 908 converts the sound input to the smart phone 900 into an audio signal. The input device 909 includes, for example, a touch sensor that detects touches on the screen of the display device 910, a keypad, a keyboard, buttons, switches, etc., and accepts operations or information input from the user. The display device 910 includes a screen such as a liquid crystal display (LCD) or an organic light emitting diode (OLED) display, and displays the output image of the smart phone 900. The speaker 911 converts the audio signal output from the smart phone 900 into audio.

[0188] The radio communication interface 912 supports any cellular communication system such as LTE or LTE-Advanced and performs radio communication. The radio communication interface 912 generally may include a BB processor 913, an RF circuit 914, etc. The BB processor 913 may perform, for example, encoding / decoding, modulation / demodulation, multiplexing / demultiplexing, etc., and perform various types of signal processing for radio communication. On the other hand, the RF circuit 914 may include mixers, filters, amplifiers, etc., and transmit and receive radio signals via an antenna 916. The radio communication interface 912 may be a single-chip module in which the BB processor 913 and the RF circuit 914 are integrated. The radio communication interface 912 may include multiple BB processors 913 and multiple RF circuits 914, as Figure 10 shown. Note that although Figure 10 the figure shows an example in which the radio communication interface 912 includes multiple BB processors 913 and multiple RF circuits 914, the radio communication interface 912 may include a single BB processor 913 or a single RF circuit 914.

[0189] In addition, in addition to the cellular communication system, the radio communication interface 912 may also support other types of radio communication systems, such as short-range radio communication systems, near-field communication systems, or wireless local area network (LAN) systems, and in this case, the radio communication interface 912 may include a BB processor 913 and an RF circuit 914 for each radio communication system.

[0190] Each antenna switch 915 switches the connection destination of the antenna 916 among a plurality of circuits (for example, circuits for different radio communication systems) included in the radio communication interface 912.

[0191] Each of the antennas 916 includes one or more antenna elements (for example, a plurality of antenna elements constituting a MIMO antenna), and is used for transmitting and receiving radio signals via the radio communication interface 912. As Figure 10 shown, the smart phone 900 may include a plurality of antennas 916. Note that although Figure 10 the figure shows an example in which the smart phone 900 includes a plurality of antennas 916, the smart phone 900 may also include a single antenna 916.

[0192] In addition, the smart phone 900 may be provided with an antenna 916 for each radio communication system. In this case, the antenna switch 915 may be omitted from the configuration of the smart phone 900.

[0193] The bus 917 interconnects the processor 901, the memory 902, the storage device 903, the external connection interface 904, the camera 906, the sensor 907, the microphone 908, the input device 909, the display device 910, the speaker 911, the wireless communication interface 912, and the auxiliary controller 919. The battery 918 supplies power to each block of the smart phone 900 shown in Figure 10 via a power supply line, which is partially shown by a broken line in the figure. The auxiliary controller 919 operates, for example, the minimally necessary functions of the smart phone 900 in the sleep mode.

[0194] In Figure 10 the smart phone 900 shown, one or more constituent elements (for example, at least one of the communication control unit 241, the information acquisition unit 243, the determination unit 245, and the notification unit 247) included in the terminal device 200 described in the reference Figure 3 can also be installed in the radio communication interface 912. Alternatively, at least some of these constituent elements can be installed in the processor 901 or the auxiliary controller 919. As an example, the smart phone 900 can incorporate a module including a part (for example, the BB processor 913) or all of the wireless communication interface 912, the processor 901, and / or the auxiliary controller 919. One or more of the foregoing constituent elements can also be installed in the module. In this case, the module can store a program for causing the processor to function as one or more constituent elements (in other words, a program for causing the processor to execute the operations of one or more constituent elements) and can execute the program. As another example, a program for causing the processor to function as one or more constituent elements can be installed in the smart phone 900, and the radio communication interface 912 (for example, the BB processor 913), the processor 901, and / or the auxiliary controller 919 can execute the program. In this way, the smart phone 900 or the module can be provided as a device including one or more constituent elements, and a program for causing the processor to function as one or more constituent elements can be provided. In addition, a readable recording medium on which the program is recorded can be provided.

[0195] In addition, in Figure 10 the smart phone 900 shown, for example, the radio communication unit 220 described in the reference Figure 3 can also be installed in the radio communication interface 912 (for example, the RF circuit 914). In addition, the antenna unit 210 can be installed in the antenna 916. In addition, the storage unit 230 can be installed in the memory 902.

[0196] (Second application example)

[0197] Figure 11FIG. is a block diagram showing an example of a schematic configuration of an in-vehicle navigation device 920 to which the technology according to the present disclosure can be applied. The in-vehicle navigation device 920 includes a processor 921, a memory 922, a Global Positioning System (GPS) module 924, a sensor 925, a data interface 926, a content player 927, a storage medium interface 928, an input device 929, a display device 930, a speaker 931, a radio communication interface 933, one or more antenna switches 936, one or more antennas 937, and a battery 938.

[0198] The processor 921 may be, for example, a CPU or an SoC, and controls the navigation function and other functions of the in-vehicle navigation device 920. The memory 922 includes a RAM and a ROM, and stores programs and data executed by the processor 921.

[0199] The GPS module 924 uses GPS signals received from GPS satellites to measure the position (e.g., latitude, longitude, and altitude) of the in-vehicle navigation device 920. The sensor 925 may include a sensor group that includes, for example, a gyro sensor, a geomagnetic sensor, a barometric pressure sensor, etc. The data interface 926 is connected to the in-vehicle network 941 via a terminal (not shown), for example, and acquires data generated on the vehicle side (such as vehicle speed data).

[0200] The content player 927 plays back content stored in a storage medium (e.g., a CD or a DVD) inserted into the storage medium interface 928. The input device 929 includes, for example, a touch sensor that detects touches on the screen, buttons, switches, etc. of the display device 930, and accepts operations or information input from the user. The display device 930 includes a screen such as an LCD or an OLED display, and displays images of the navigation function or the played-back content. The speaker 931 outputs audio of the navigation function or the played-back content.

[0201] The radio communication interface 933 supports any cellular communication system such as LTE or LTE-Advanced, and performs radio communication. The radio communication interface 933 generally may include a BB processor 934, an RF circuit 935, etc. The BB processor 934 may, for example, perform encoding / decoding, modulation / demodulation, multiplexing / demultiplexing, etc., and perform various types of signal processing for radio communication. On the other hand, the RF circuit 935 may include a mixer, a filter, an amplifier, etc., and transmits and receives radio signals via the antenna 937. The radio communication interface 933 may be a single-chip module in which the BB processor 934 and the RF circuit 935 are integrated. The radio communication interface 933 may include multiple BB processors 934 and multiple RF circuits 935, as Figure 11 shown. Note that, although Figure 11Illustrated is an example in which the radio communication interface 933 includes a plurality of BB processors 934 and a plurality of RF circuits 935, but the radio communication interface 933 may include a single BB processor 934 or a single RF circuit 935.

[0202] In addition to the cellular communication system, the radio communication interface 933 may also support other types of radio communication systems, such as short-range radio communication systems, near-field communication systems, or wireless LAN systems. In this case, the radio communication interface 933 may include a BB processor 934 and an RF circuit 935 for each radio communication system.

[0203] Each antenna switch 936 switches the connection destination of the antenna 937 among a plurality of circuits (e.g., circuits for different radio communication systems) included in the radio communication interface 933.

[0204] Each of the antennas 937 includes one or more antenna elements (e.g., a plurality of antenna elements constituting a MIMO antenna) and is used for transmitting and receiving radio signals via the radio communication interface 933. As Figure 11 shown, the car navigation device 920 may include a plurality of antennas 937. Note that although Figure 11 an example in which the car navigation device 920 includes a plurality of antennas 937 is illustrated, the car navigation device 920 may also include a single antenna 937.

[0205] In addition, the car navigation device 920 may include an antenna 937 for each radio communication system. In this case, the antenna switch 936 may be omitted from the configuration of the car navigation device 920.

[0206] The battery 938 supplies power to each block of the car navigation device 920 shown in Figure 11 via a power supply line, which is partially shown as a broken line in the figure. In addition, the battery 938 stores the power supplied from the vehicle side.

[0207] In Figure 11 the car navigation device 920 shown, included in the reference Figure 3One or more constituent elements in the described terminal device 200 (e.g., at least one of the communication control unit 241, the information acquisition unit 243, the determination unit 245, and the notification unit 247) may also be installed in the radio communication interface 933. Alternatively, at least some of these constituent elements may be installed in the processor 921. As an example, the car navigation device 920 may incorporate a part (e.g., the BB processor 934) or all of the radio communication interface 933 and / or a module of the processor 921. One or more of the foregoing constituent elements may also be installed in a module. In this case, the module may store a program for causing the processor to function as one or more constituent elements (in other words, a program for causing the processor to execute the operations of one or more constituent elements) and may execute the program. As another example, a program for causing the processor to function as one or more constituent elements may be installed in the car navigation device 920, and the radio communication interface 933 (e.g., the BB processor 934) and / or the processor 921 may execute the program. In this way, the car navigation device 920 or the module may be provided as a device including one or more constituent elements, and a program for causing the processor to function as one or more constituent elements may be provided. Further, a readable recording medium having the program recorded thereon may be provided.

[0208] In addition, in Figure 11 the car navigation device 920 shown, for example, with reference to Figure 3 the radio communication unit 220 described may also be installed in the radio communication interface 933 (e.g., the RF circuit 935). Additionally, the antenna unit 210 may be installed in the antenna 937. Further, the storage unit 230 may be installed in the memory 922.

[0209] The technology of the present disclosure may also be implemented as a vehicle system (or vehicle) 940 including one or more blocks of the above-mentioned car navigation device 920, the in-vehicle network 941, and the vehicle-side module 942. The vehicle-side module 942 generates vehicle data such as vehicle speed, engine speed, and fault information and outputs the generated data to the in-vehicle network 941.

[0210] <<5. Conclusion>>

[0211] As described above, in the system according to an embodiment of the present disclosure, the terminal device includes: a communication unit that performs radio communication; and a control unit that performs carrier sensing with a base station and performs control to transmit a radio signal via a carrier specified by the base station according to the sensing result. The foregoing control unit performs control such that information related to the transmission of uplink control information is acquired from the base station when the transmission of uplink control information via the carrier is suppressed.

[0212] According to the foregoing configuration, even when the transmission of control information (e.g., uplink control information) is suppressed in a case where an unlicensed frequency band is used for communication in a primary cell according to NR-U, unnecessary retransmission of information and data can be prevented. Therefore, since a situation where radio communication resources are unnecessarily consumed can be prevented, the utilization rate of the overall system resources can be further improved. Therefore, the technology according to an embodiment of the present disclosure can implement radio communication using an unlicensed frequency band in a more preferable manner.

[0213] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to or restricted by these examples. It will be apparent to those of ordinary skill in the technical field of the present disclosure that various modification examples or revision examples can be conceived within the scope of the technical concept set forth in the claims, and it is naturally understood that these modification examples or revision examples fall within the technical scope of the present disclosure.

[0214] In addition, the advantageous effects described in this specification are merely illustrative or exemplary and not restrictive. That is, the technology according to the present invention can provide other advantageous effects that are apparent to those skilled in the art from the description of this specification in addition to or in place of the foregoing advantageous effects.

[0215] Note that the following configurations also fall within the technical scope of the present disclosure.

[0216] (1) A communication device, comprising:

[0217] a communication unit that performs radio communication; and

[0218] a control unit that performs carrier sensing with a base station and performs control to transmit a radio signal via a carrier designated by the base station according to the sensing result,

[0219] wherein the control unit performs control such that information related to the transmission of uplink control information is acquired from the base station when the transmission of uplink control information via the carrier is suppressed.

[0220] (2) The communication device according to (1), wherein the control unit suppresses the transmission of uplink control information based on the sensing result.

[0221] (3) The communication device according to (1), wherein the control unit suppresses the transmission of uplink control information based on an instruction from the base station.

[0222] (4) The communication device according to (3), wherein the control unit suppresses the transmission of uplink control information according to the base station's control of the transmission timing of uplink control information.

[0223] (5) The communication device according to (1), wherein the control unit suppresses the transmission of uplink control information according to the channel congestion degree.

[0224] (6) The communication device according to any one of (1) to (5), wherein the control unit acquires information related to the uplink control information to be transmitted to the base station as information related to the transmission of the uplink control information.

[0225] (7) The communication device according to (6), wherein the control unit performs control such that after associating a code related to error detection with the uplink control information, the uplink control information is transmitted to the base station.

[0226] (8) The communication device according to (7), wherein after performing control such that the number of bits of the uplink control information is greater than or equal to a threshold value, the control unit associates a code related to error detection with the controlled uplink control information.

[0227] (9) The communication device according to (8), wherein the control unit performs control such that the number of bits of the uplink control information is greater than or equal to the threshold value by associating other control information with the uplink control information.

[0228] (10) The communication device according to (9), wherein the other control information includes information related to the channel congestion degree.

[0229] (11) The communication device according to any one of (1) to (5),

[0230] wherein the control unit:

[0231] acquires information related to the uplink resources available for the transmission of the uplink control information as information related to the transmission of the uplink control information, and

[0232] performs control such that when suppressing the transmission of the uplink control information, the uplink control information is transmitted by using the uplink resources.

[0233] (12) The communication device according to any one of (1) to (11), wherein the control unit controls the bit size related to the transmission of the uplink control information suppressed from being transmitted according to a predetermined condition.

[0234] (13) The communication device according to (12), wherein the control unit controls the bit size according to an instruction from the base station.

[0235] (14) The communication device according to (12), wherein the control unit extends the bit size related to the transmission of uplink control information in response to not having received a notification related to the uplink control information from the base station.

[0236] (15) The communication device according to (12), wherein when the bit size has been controlled, the control unit performs control such that information related to the controlled bit size is notified to the base station.

[0237] (16) The communication device according to (15), wherein the control unit performs control such that information related to the bit size is notified to the base station by associating the information with a sequence related to communication with the base station.

[0238] (17) The communication device according to (16), wherein the control unit associates information related to the bit size with a channel scrambling sequence.

[0239] (18) A communication device, comprising:

[0240] a communication unit that performs radio communication; and

[0241] a control unit that performs control such that a radio signal is transmitted via a carrier specified for a terminal device according to a result of carrier sensing with the terminal device,

[0242] wherein the control unit performs control such that information related to the transmission of uplink control information is transmitted to the terminal device in a case where transmission of uplink control information via the carrier by the terminal device is suppressed.

[0243] (19) A communication method executed by a computer, the method comprising:

[0244] performing radio communication; and

[0245] performing carrier sensing with a base station and performing control such that a radio signal is transmitted via a carrier specified by the base station according to the sensed result,

[0246] wherein control is performed such that information related to the transmission of uplink control information is acquired from the base station in a case where transmission of uplink control information via the carrier is suppressed.

[0247] (20) A communication method executed by a computer, the method comprising:

[0248] performing radio communication; and

[0249] performing control such that a radio signal is transmitted via a carrier specified for a terminal device according to a result of carrier sensing with the terminal device,

[0250] Execute control so that information related to the transmission of uplink control information is transmitted to the terminal device when the transmission of uplink control information via a carrier by the terminal device is suppressed.

[0251] (21) A program that causes a computer to perform the following operations:

[0252] Perform radio communication; and

[0253] Perform carrier sensing with a base station and execute control so that a radio signal is transmitted via a carrier designated by the base station according to the result of the sensing,

[0254] wherein control is executed so that information related to the transmission of uplink control information is obtained from the base station when the transmission of uplink control information via a carrier is suppressed.

[0255] (22) A program that causes a computer to perform the following operations:

[0256] Perform radio communication; and

[0257] Execute control so that a radio signal via a carrier designated for the terminal device is transmitted according to the result of carrier sensing with the terminal device,

[0258] wherein control is executed so that information related to the transmission of uplink control information is transmitted to the terminal device when the transmission of uplink control information via a carrier by the terminal device is suppressed.

[0259] List of reference numerals

[0260] 1 System

[0261] 100 Base station

[0262] 110 Antenna unit

[0263] 120 Radio communication unit

[0264] 130 Network communication unit

[0265] 140 Storage unit

[0266] 150 Control unit

[0267] 151 Communication control unit

[0268] 153 Information acquisition unit

[0269] 155 Determination unit

[0270] 157 Notification unit

[0271] 200 Terminal device

[0272] 210 Antenna unit

[0273] 220 Radio communication unit

[0274] 230 Storage unit

[0275] 240 Control unit

[0276] 241 Communication control unit

[0277] 243 Information acquisition unit

[0278] 245 Determination unit

[0279] 247 Notification unit

Claims

1. A communication device, comprising: a communication unit that performs radio communication; and a control unit that performs carrier sensing with a base station and performs control to transmit a radio signal via a carrier designated by the base station according to a result of the sensing, wherein the control unit performs control to obtain information related to transmission of the uplink control information in a case where transmission of the uplink control information via a carrier is suppressed from the base station, wherein the control unit obtains information related to the uplink control information that is an object of transmission to the base station as information related to transmission of the uplink control information, wherein the control unit performs control to transmit the uplink control information to the base station after associating a code related to error detection with the uplink control information, and wherein after performing control to make the number of bits of the uplink control information greater than or equal to a threshold, the control unit associates a code related to error detection with the uplink control information after the control.

2. The communication device according to claim 1, wherein the control unit suppresses transmission of the uplink control information based on the result of the sensing.

3. The communication device according to claim 1, wherein the control unit suppresses transmission of the uplink control information based on an instruction from the base station.

4. The communication device according to claim 3, wherein the control unit suppresses transmission of the uplink control information according to control by the base station of a transmission timing of the uplink control information.

5. The communication device according to claim 1, wherein the control unit suppresses transmission of the uplink control information according to a channel congestion degree.

6. The communication device according to claim 1, wherein the control unit performs control to make the number of bits of the uplink control information greater than or equal to the threshold by associating other control information with the uplink control information.

7. The communication device according to claim 6, wherein the other control information includes information related to a channel congestion degree.

8. The communication device according to claim 1, wherein the control unit: obtains information related to an uplink resource available for transmission of the uplink control information as information related to transmission of the uplink control information, and performs control to transmit the uplink control information by using the uplink resource when suppressing transmission of the uplink control information.

9. The communication device according to claim 1, wherein the control unit controls a bit size related to transmission of the uplink control information whose transmission is suppressed according to a predetermined condition.

10. The communication device according to claim 9, wherein the control unit controls the bit size based on an instruction from the base station.

11. The communication device according to claim 9, wherein the control unit extends a bit size related to transmission of the uplink control information in response to not having received a notification related to the uplink control information from the base station.

12. The communication device according to claim 9, wherein, when the bit size has been controlled, the control unit performs control such that information related to the controlled bit size is notified to the base station.

13. The communication device according to claim 12, wherein the control unit performs control such that information related to the bit size is notified to the base station by associating the information with a sequence related to communication with the base station.

14. The communication device according to claim 13, wherein the control unit associates information related to the bit size with a channel scrambling sequence.

15. A communication device, comprising: a communication unit that performs radio communication; and a control unit that performs control such that a radio signal is transmitted via a carrier specified for the terminal device according to a result of carrier sensing with the terminal device, wherein the control unit performs control such that information related to transmission of the uplink control information is transmitted to the terminal device in a case where transmission of the uplink control information via the carrier by the terminal device is suppressed, wherein a bit size related to transmission of the uplink control information whose transmission is suppressed is controlled by the terminal device according to a predetermined condition, wherein information related to the controlled bit size is acquired from the terminal device when the terminal device has controlled the bit size, and wherein information related to the bit size is acquired from the terminal device by association of the information related to the bit size with a sequence related to communication with the terminal device.

16. A communication method executed by a computer, the method comprising: performing radio communication; and performing carrier sensing with a base station and performing control such that a radio signal is transmitted via a carrier specified by the base station according to a result of the sensing, wherein control is performed such that information related to transmission of the uplink control information is acquired from the base station in a case where transmission of the uplink control information via the carrier is suppressed, wherein information related to the uplink control information that is an object of transmission to the base station is acquired as information related to transmission of the uplink control information, wherein control is performed such that after associating a code related to error detection with the uplink control information, the uplink control information is transmitted to the base station, and wherein after performing control such that the number of bits of the uplink control information is greater than or equal to a threshold, a code related to error detection is associated with the controlled uplink control information.

17. A communication method executed by a computer, the method comprising: performing radio communication; and performing control such that a radio signal is transmitted via a carrier specified for the terminal device according to a result of carrier sensing with the terminal device, Execute control so that information related to the transmission of uplink control information is sent to the terminal device when the transmission of uplink control information by the terminal device via a carrier is suppressed. The bit size related to the transmission of the suppressed uplink control information is controlled by the terminal device according to a predetermined condition. When the terminal device has controlled the bit size, obtain information related to the controlled bit size from the terminal device, and Obtain information related to the bit size from the terminal device by associating the information related to the bit size with a sequence related to the communication with the terminal device.

18. A readable recording medium having a program recorded thereon, which when executed by a computer causes the computer to execute the communication method according to claim 16.

19. A readable recording medium having a program recorded thereon, which when executed by a computer causes the computer to execute the communication method according to claim 17.

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