Patent Description:
A wireless access method and a wireless network 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)") are under discussion in the 3rd Generation Partnership Project (3GPP). Note that LTE includes LTE-A, LTE-A Pro, and EUTRA, and NR includes the fifth-generation mobile wireless communication (<NUM>), NRAT, and FEUTRA in the following description. In LTE and NR, a base station apparatus (base station) is also referred to as an evolved Node B (eNodeB), and a terminal apparatus (mobile station, mobile station apparatus, or terminal) is also referred to as user equipment (UE). LTE and NR are each a cellular communication system in which a plurality of areas covered by a base station apparatus is arranged in a cell-like manner. A single base station apparatus may manage a plurality of cells.

NR is a next-generation wireless access method to replace LTE, and is a radio access technology (RAT) different from LTE. NR is an access technology that can be applied to various use cases including enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra reliable and low latency communications (URLLC). NR is studied with a view to achieving a technology framework for dealing with usage scenarios, requirements, deployment scenarios, and the like in those use cases. Details of operation in an unlicensed band, which is one of the use cases, are disclosed in, for example, Non-Patent Document <NUM>.

In <CIT>, a wireless device capable of transmitting a plurality of frames in parallel over multiple frequency channels is described. A MAC controller of the device determines which frequency channels should be used for transmissions.

<CIT> describes a listen-before-talk method for transmission over aggregated carriers.

Document <CIT> describes a Clear Channel Assessment (CCA) method where one device performs CCA on behalf on another device.

In <CIT>, a listen before talk (LBT) scheme is described that starts LBT only if LBT is found to be necessary.

Incidentally, there are cases where NR requires communication with lower delay and higher reliability than LTE. In particular, NR is assumed to be used in various use cases. Therefore, there is a demand for providing a technique capable of allowing flexible design according to the use cases and thus enhancing transmission efficiency of the entire system.

Accordingly, the present disclosure proposes a technique capable of implementing low-delay and highly reliable communication in a more suitable manner.

According to the present disclosure, there is provided a communication apparatus, a communication method and a program as defined in the independent claims.

As described above, according to the present disclosure, there is provided a technique capable of implementing low-delay and highly reliable communication in a more suitable manner.

Note that the above-described effect is not necessarily restrictive, and any of the effects set forth in the present specification or another effect that can be derived from the present specification may be achieved together with or instead of the above-described effect.

The embodiments of <FIG> and <FIG> and their associated text are part of the invention and covered by the claims. All other exemplary embodiments disclosed below are merely explanatory, and are not part of the invention.

A preferred embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that in the present specification and the drawings, the same reference numerals are assigned to constituent elements having substantially the same functional configurations, and redundant description will be thus omitted.

Note that description will be provided in the following order.

First, an example of a schematic configuration of a system <NUM> according to an embodiment of the present disclosure will be described with reference to <FIG> is an explanatory diagram for describing the example of the schematic configuration of the system <NUM> according to the embodiment of the present disclosure. As shown in <FIG>, the system <NUM> includes a wireless communication apparatus <NUM> and a terminal apparatus <NUM>. Here, the terminal apparatus <NUM> is also referred to as a user. The user may also be referred to as a UE. A wireless communication apparatus 100C is also referred to as a UE-Relay. Here, the UE may be a UE defined in LTE or LTE-A. In addition, the UE-Relay may be a Prose UE to Network Relay which is under discussion in 3GPP, or may more generally refer to a communication device.

The wireless communication apparatus <NUM> is an apparatus that provides wireless communication services to subordinate devices. For example, a wireless communication apparatus 100A is a base station of a cellular system (or a mobile communication system). The base station 100A performs wireless communication with an apparatus (for example, a terminal apparatus 200A) located inside a cell 10A of the base station 100A. For example, the base station 100A transmits a downlink signal to the terminal apparatus 200A, and receives an uplink signal from the terminal apparatus 200A.

The base station 100A is logically connected to another base station through, for example, an X2 interface, and can transmit and receive control information and the like. Furthermore, the base station 100A is logically connected to a so-called core network (not shown) through, for example, an S1 interface, and can transmit and receive control information and the like. Note that communication between these apparatuses can be physically relayed by various devices.

Here, the wireless communication apparatus 100A shown in <FIG> is a macrocell base station. The cell 10A shown in <FIG> is a macrocell. Meanwhile, a wireless communication apparatus 100B and the wireless communication apparatus 100C are master devices that operate small cells 10B and 10C, respectively. As an example, the master device 100B is a small cell base station provided in such a manner as to be fixed. The small cell base station 100B establishes a wireless backhaul link with the macrocell base station 100A, and also establishes an access link with one or more terminal apparatuses (for example, terminal apparatuses 200B) in the small cell 10B. Note that the wireless communication apparatus 100B may be a relay node defined by 3GPP. The master device 100C is a dynamic access point (AP). The dynamic AP 100C is a mobile device that operates the small cell 10C dynamically. The dynamic AP 100C establishes a wireless backhaul link with the macrocell base station 100A, and also establishes an access link with one or more terminal apparatuses (for example, terminal apparatuses 200C) in the small cell 10C. The dynamic AP 100C may be a terminal apparatus equipped with hardware or software that can operate as, for example, a base station or a wireless access point. The small cell 10C in this case is a localized network (virtual cell) dynamically formed.

For example, the cell 10A may be operated according to any wireless communication system such as LTE, LTE-Advanced (LTE-A), LTE-ADVANCED PRO, GSM (registered trademark), UMTS, W-CDMA, CDMA2000, WiMAX, WiMAX <NUM>, or IEEE <NUM>.

Note that the small cell is a concept that may include various types of cell smaller than a macrocell (for example, femtocell, nanocell, picocell, microcell, and the like) to be arranged with an overlap or without an overlap with the macrocell. In one example, a small cell is operated by a dedicated base station. In another example, a terminal serving as a master device operates a small cell by temporarily operating as a small cell base station. A so-called relay node can also be regarded as a form of small cell base station. A wireless communication apparatus functioning as a master station of a relay node is also referred to as a donor base station. The donor base station may refer to a DeNB in LTE, or may more generally refer to the master station of a relay node.

The terminal apparatus <NUM> can communicate in the cellular system (or mobile communication system). The terminal apparatus <NUM> performs wireless communication with a wireless communication apparatus (for example, the base station 100A, or the master device 100B or 100C) of the cellular system. For example, the terminal apparatus 200A receives the downlink signal from the base station 100A, and transmits the uplink signal to the base station 100A.

Furthermore, not only so-called UEs but also, for example, so-called low cost UEs such as an MTC terminal, an enhanced MTC (eMTC) terminal, and an NB-IoT terminal, may be applied as the terminal apparatuses <NUM>.

The schematic configuration of the system <NUM> has been described above. However, the present technology is not limited to the example shown in <FIG>. For example, a configuration including no master device, Small Cell Enhancement (SCE), a Heterogeneous Network (HetNet), an MTC network, or the like may be adopted as a configuration of the system <NUM>. Furthermore, as another example of the configuration of the system <NUM>, a master device may be connected to a small cell such that a cell is constructed under the small cell.

Next, a configuration of the base station <NUM> according to the embodiment of the present disclosure will be described with reference to <FIG> is a block diagram showing an example of the configuration of the base station <NUM> according to the embodiment of the present disclosure. Referring to <FIG>, the base station <NUM> includes an antenna unit <NUM>, a wireless communication unit <NUM>, a network communication unit <NUM>, a storage unit <NUM>, and a processing unit <NUM>.

The antenna unit <NUM> emits a signal output from the wireless communication unit <NUM>, as radio waves in the air. Furthermore, the antenna unit <NUM> converts radio waves in the air into a signal, and outputs the signal to the wireless communication unit <NUM>.

The wireless communication unit <NUM> transmits and receives signals. For example, the wireless communication unit <NUM> transmits a downlink signal to a terminal apparatus, and receives an uplink signal from the terminal apparatus.

Furthermore, as described above, there are cases where a terminal apparatus operates as a relay terminal (the wireless communication apparatus 100C in <FIG>) to relay communication between a remote terminal (the terminal apparatus 200C in <FIG>) and the base station in the system <NUM> according to the present embodiment. In such a case, the wireless communication unit <NUM> in, for example, the wireless communication apparatus 100C corresponding to the relay terminal may transmit/receive sidelink signals to/from the remote terminal.

The network communication unit <NUM> transmits and receives information. For example, the network communication unit <NUM> transmits information to other nodes, and receives information from other nodes. Examples of the other nodes described above include another base station and a core network node.

Note that, as described above, there are cases where a terminal apparatus operates as a relay terminal to relay communication between a remote terminal and the base station in the system <NUM> according to the present embodiment. In such a case, for example, the wireless communication apparatus 100C corresponding to the relay terminal need not include the network communication unit <NUM>.

The storage unit <NUM> temporarily or permanently stores a program and various data for operation of the base station <NUM>.

The processing unit <NUM> provides various functions of the base station <NUM>. The processing unit <NUM> includes a communication control unit <NUM>, an information acquisition unit <NUM>, a determination unit <NUM>, and a notification unit <NUM>. Note that the processing unit <NUM> may further include a constituent element other than these constituent elements. In other words, the processing unit <NUM> can also perform operation other than the operation of these constituent elements.

The operation of the communication control unit <NUM>, the information acquisition unit <NUM>, the determination unit <NUM>, and the notification unit <NUM> will be described in detail later.

Next, an example of a configuration of the terminal apparatus <NUM> according to the embodiment of the present disclosure will be described with reference to <FIG> is a block diagram showing the example of the configuration of the terminal apparatus <NUM> according to the embodiment of the present disclosure. As shown in <FIG>, the terminal apparatus <NUM> includes an antenna unit <NUM>, a wireless communication unit <NUM>, a storage unit <NUM>, and a processing unit <NUM>.

The wireless communication unit <NUM> transmits and receives signals. For example, the wireless communication unit <NUM> receives a downlink signal from a base station, and transmits an uplink signal to the base station.

Furthermore, as described above, there are cases where a terminal apparatus operates as a relay terminal to relay communication between a remote terminal and the base station in the system <NUM> according to the present embodiment. In such a case, the wireless communication unit <NUM> in, for example, the terminal apparatus 200C operating as the remote terminal may transmit/receive sidelink signals to/from the relay terminal.

The storage unit <NUM> temporarily or permanently stores a program and various data for operation of the terminal apparatus <NUM>.

The processing unit <NUM> provides various functions of the terminal apparatus <NUM>. For example, the processing unit <NUM> includes a communication control unit <NUM>, an information acquisition unit <NUM>, a determination unit <NUM>, and a notification unit <NUM>. Note that the processing unit <NUM> may further include a constituent element other than these constituent elements. In other words, the processing unit <NUM> can also perform operation other than the operation of these constituent elements.

Next, the following describes technical features of the system according to the embodiment of the present disclosure.

In the present embodiment, the base station <NUM> and the terminal apparatus <NUM> each support one or more radio access technologies (RATs). For example, a RAT includes LTE and NR. A single RAT corresponds to a single cell (component carrier). In other words, in a case where a plurality of RATs is supported, the RATs correspond to respective different cells. In the present embodiment, a cell is a combination of a downlink resource, an uplink resource, and/or a sidelink. Furthermore, a cell corresponding to LTE is referred to as an LTE cell, and a cell corresponding to NR is referred to as an NR cell in the following description.

Downlink communication is communication from the base station <NUM> to the terminal apparatus <NUM>. Uplink communication is communication from the terminal apparatus <NUM> to the base station <NUM>. Sidelink communication is communication from the terminal apparatus <NUM> to another terminal apparatus <NUM>.

Sidelink communication is defined for proximity direct detection and proximity direct communication between terminal apparatuses. Sidelink communication can use a frame configuration similar to frame configurations of uplink communication and downlink communication. Furthermore, sidelink communication may be limited to a subset of uplink resources and/or downlink resources.

The base station <NUM> and the terminal apparatus <NUM> can support communication using a set of one or more cells in the downlink, uplink, and/or sidelink. A set of multiple cells is also referred to as carrier aggregation or dual connectivity. Details of carrier aggregation and dual connectivity will be described later. Furthermore, each cell uses a predetermined frequency bandwidth. It is possible to predefine a maximum value, a minimum value, and values that can be set in the predetermined frequency bandwidth.

<FIG> is a diagram showing an example of the setting of a component carrier in the present embodiment. A single LTE cell and two NR cells are set in the example of <FIG>. The single LTE cell is set as a primary cell. The two NR cells are set as a primary secondary cell and a secondary cell, respectively. The two NR cells are integrated by carrier aggregation. Furthermore, the LTE cell and the NR cells are integrated by dual connectivity. Note that the LTE cell and the NR cells may be integrated by carrier aggregation. In the example of <FIG>, the LTE cell which is the primary cell can assist NR in establishing connection. Therefore, it is not necessary to support some functions such as functions for communicating in a stand-alone state. The functions for communicating in a stand-alone state include a function necessary for initial connection.

<FIG> is a diagram showing an example of the setting of a component carrier in the present embodiment. Two NR cells are set in the example of <FIG>. The two NR cells are set as a primary cell and a secondary cell, respectively, and are integrated by carrier aggregation. In this case, since the NR cells support the functions for communicating in a stand-alone state, assistance of an LTE cell is not necessary. Note that the two NR cells may be integrated by dual connectivity.

In each of the NR cells, one or more predetermined parameters are used in a certain predetermined time length (for example, a subframe). In other words, a downlink signal and an uplink signal are each generated by use of one or more predetermined parameters in the predetermined time length in the NR cell. In other words, the terminal apparatus <NUM> is based on the assumption that a downlink signal to be transmitted from the base station <NUM> and an uplink signal to be transmitted to the base station <NUM> are each generated by use of one or more predetermined parameters in the predetermined time length. Furthermore, it is possible to configure the base station <NUM> such that the downlink signal to be transmitted to the terminal apparatus <NUM> and the uplink signal to be transmitted from the terminal apparatus <NUM> are each generated by use of one or more predetermined parameters in the predetermined time length. In a case where a plurality of predetermined parameters is used, signals generated by use of those predetermined parameters are multiplexed by a predetermined method. The predetermined method includes, for example, frequency division multiplexing (FDM), time division multiplexing (TDM), code division multiplexing (CDM), spatial division multiplexing (SDM), and/or the like.

Multiple types of combination of predetermined parameters to be set in the NR cell can be predefined as parameter sets.

<FIG> is a diagram showing examples of parameter sets related to transmission signals in the NR cell. In the examples of <FIG>, the parameter sets each include parameters related to transmission signals, that is, subframe spacing, the number of subcarriers per resource block in the NR cell, the number of symbols per subframe, and a CP-length type. The CP-length type is the type of CP length to be used in the NR cell. For example, CP-length type <NUM> corresponds to a normal CP in LTE, and CP-length type <NUM> corresponds to an extended CP in LTE.

The parameter sets related to transmission signals in the NR cell can be separately defined for the downlink and the uplink. Furthermore, the parameter sets related to transmission signals in the NR cell can be set independently for the downlink and the uplink.

<FIG> is a diagram showing an example of a downlink subframe of NR in the present embodiment. In the example of <FIG>, signals generated by use of parameter set <NUM>, parameter set <NUM>, and parameter set <NUM> are frequency-division multiplexed in a cell (system bandwidth). The diagram shown in <FIG> is also referred to as an NR downlink resource grid. The base station <NUM> can transmit an NR physical downlink channel and/or an NR physical downlink signal in a downlink subframe for downlink to the terminal apparatus <NUM>. The terminal apparatus <NUM> can receive the NR physical downlink channel and/or the NR physical downlink signal in the downlink subframe for downlink from the base station <NUM>.

<FIG> is a diagram showing an example of an uplink subframe of NR in the present embodiment. In the example of <FIG>, the signals generated by use of parameter set <NUM>, parameter set <NUM>, and parameter set <NUM> are frequency-division multiplexed in a cell (system bandwidth). The diagram shown in <FIG> is also referred to as an NR uplink resource grid. The base station <NUM> can transmit an NR physical uplink channel and/or an NR physical uplink signal in an uplink subframe for uplink to the terminal apparatus <NUM>. The terminal apparatus <NUM> can receive the NR physical uplink channel and/or the NR physical uplink signal in the uplink subframe for uplink from the base station <NUM>.

The base station <NUM> and the terminal apparatus <NUM> can each use various methods for signaling (notification, information, and setting) of control information. Signaling of control information can be performed at various layers. Examples of signaling of control information include physical layer signaling, RRC signaling, MAC signaling, and the like. Physical layer signaling is signaling through a physical layer (layer). RRC signaling is signaling through an RRC layer. MAC signaling is signaling through a MAC layer. RRC signaling is dedicated RRC signaling for notifying the terminal apparatus <NUM> of unique control information, or common RRC signaling for notifying the base station <NUM> of unique control information. Signaling to be used by layers higher than a physical layer, such as RRC signaling or MAC signaling, is also referred to as higher-layer signaling.

RRC signaling is implemented by signaling RRC parameters. MAC signaling is implemented by signaling a MAC control element. Physical layer signaling is implemented by signaling downlink control information (DCI) or uplink control information (UCI). The RRC parameters and the MAC control element are transmitted by use of PDSCH or PUSCH. The DCI is transmitted by use of PDCCH or EPDCCH. The UCI is transmitted by use of PUCCH or PUSCH. RRC signaling and MAC signaling are used to signal semi-static control information and also referred to as semi-static signaling. Physical layer signaling is used to signal dynamic control information and also referred to as dynamic signaling. The DCI is used for PDSCH scheduling, PUSCH scheduling, or the like. The UCI is used for CSI reporting, HARQ-ACK reporting, a scheduling request (SR), and/or the like.

The terminal apparatus <NUM> is configured with a plurality of cells, and can perform multicarrier transmission. Communication to be performed by the terminal apparatus <NUM> by use of the plurality of cells is referred to as carrier aggregation (CA) or dual connectivity (DC). Details described in the present embodiment can be applied to each or some of the plurality of cells set for the terminal apparatus <NUM>. The cells set for the terminal apparatus <NUM> are also referred to as serving cells.

In CA, the plurality of set serving cells includes a single primary cell (PCell) and one or more secondary cells (SCells). A single primary cell and one or more secondary cells can be set for the terminal apparatus <NUM> supporting CA.

The primary cell is a serving cell on which an initial connection establishment procedure has been performed, a serving cell on which a connection re-establishment procedure has been started, or a cell designated as a primary cell in a handover procedure. The primary cell operates at a primary frequency. The secondary cell can be set after the establishment or re-establishment of connection. The secondary cell operates at a secondary frequency. Note that the connection is also referred to as an RRC connection.

DC is an operation in which a predetermined terminal apparatus <NUM> consumes radio resources provided by at least two different network points. The network points are a master base station apparatus (Master eNB (MeNB)) and a secondary base station apparatus (Secondary eNB (SeNB)). Dual connectivity refers to establishment of RRC connections to at least two network points, to be performed by the terminal apparatus <NUM>. In dual connectivity, the two network points may be connected by a non-ideal backhaul.

In DC, the base station <NUM> connected to at least an S1-mobility management entity (MME) and serving as a mobility anchor in a core network is referred to as a master base station apparatus. Furthermore, the base station <NUM> that is not the master base station apparatus and provides an additional radio resource to the terminal apparatus <NUM> is referred to as a secondary base station apparatus. A group of serving cells associated with the master base station apparatus is also referred to as a master cell group (MCG). A group of serving cells associated with the secondary base station apparatus is also referred to as a secondary cell group (SCG).

A primary cell belongs to the MCG in DC. Furthermore, in the SCG, a secondary cell corresponding to a primary cell is referred to as a primary secondary cell (PSCell). A function (capability and performance) equivalent to that of a PCell (a base station apparatus included in the PCell) may be supported in a PSCell (a base station apparatus included in the pSCell). Furthermore, only some of the functions of the PCell may be supported in the PSCell. For example, the function of performing PDCCH transmission by use of a search space different from CSS or USS may be supported in the PSCell. Furthermore, the PSCell may be constantly in a state of activation. Moreover, the PSCell is a cell which can receive PUCCH.

In DC, radio bearers (date radio bearers (DRBs) and/or signaling radio bearers (SRBs)) may be allocated separately to the MeNB and the SeNB. A duplex mode may be set separately for the MCG (PCell) and the SCG (PSCell). The MCG (PCell) and the SCG (PSCell) need not be synchronized with each other. A plurality of parameters for timing adjustment (timing advance group (TAG)) may be set independently for the MCG (PCell) and the SCG (PSCell). In dual connectivity, the terminal apparatus <NUM> transmits UCI corresponding to a cell in the MCG by using only the MeNB (PCell), and transmits UCI corresponding to a cell in the SCG by using only the SeNB (pSCell). A transmission method using PUCCH and/or PUSCH is applied to transmission of each UCI in each cell group.

PUCCH and PBCH (MIB) are transmitted only on the PCell or PSCell. Furthermore, PRACH is transmitted only on the PCell or PSCell unless a plurality of timing advance groups (TAGs) is set between cells in a CG.

Semi-persistent scheduling (SPS) and discontinuous transmission (DRX) may be performed in the PCell or PSCell. The same DRX as that performed in the PCell or PSCell of the same cell group may be performed in the secondary cell.

In the secondary cell, information/parameters related to MAC configuration are basically shared with the PCell or PSCell of the same cell group. Some of the parameters may be set for each secondary cell. Some timers and counters may be applied only to the PCell or PSCell.

In CA, a cell to which the TDD system is applied and a cell to which the FDD system is applied may be aggregated. In a case where the cell to which TDD is applied and the cell to which FDD is applied are aggregated, the present disclosure can be applied to either the cell to which TDD is applied or the cell to which FDD is applied.

The terminal apparatus <NUM> transmits, to the base station <NUM>, information indicating combinations of bands for which CA is supported by the terminal apparatus <NUM>. The terminal apparatus <NUM> transmits, to the base station <NUM>, information indicating whether or not each of the combinations of bands supports simultaneous transmission and reception in the plurality of serving cells in a plurality of different bands.

In NR, physical channels and/or physical signals can be transmitted by self-contained transmission. <FIG> is a diagram showing an example of a frame configuration of self-contained transmission in the present embodiment. In self-contained transmission, a single transmission/reception includes continuous downlink transmission, GP, and continuous downlink transmission in order from the top. The continuous downlink transmission includes at least a single piece of downlink control information and DMRS. The downlink control information provides an instruction to receive a downlink physical channel included in the continuous downlink transmission or an instruction to transmit an uplink physical channel included in the continuous uplink transmission. In a case where the instruction to receive the downlink physical channel has been provided by the downlink control information, a terminal apparatus <NUM> attempts to receive the downlink physical channel on the basis of the downlink control information. Then, the terminal apparatus <NUM> transmits a result as to whether or not the downlink physical channel has been successfully received (successfully decoded), through an uplink control channel included in the uplink transmission allocated after the GP. Meanwhile, in a case where the instruction to transmit the uplink physical channel has been provided by the downlink control information, the uplink physical channel to be transmitted on the basis of the downlink control information is included in uplink transmission, and then transmitted. As described above, it is possible to immediately cope with an increase or decrease in uplink and downlink traffic rates by flexibly switching between uplink data transmission and downlink data transmission according to the downlink control information. Furthermore, it is possible to achieve low-delay downlink communication by providing notification of success or failure in downlink reception through uplink transmission immediately following the downlink reception.

A unit slot time is the smallest time unit defining downlink transmission, GP, or uplink transmission. The unit slot time is reserved for any of downlink transmission, GP, and uplink transmission. The unit slot time does not include both downlink transmission and uplink transmission. The unit slot time may be the minimum transmission time for a channel associated with DMRS included in the unit slot time. One unit slot time is defined by, for example, an NR sampling interval (Ts) or an integral multiple of a symbol length.

A unit frame time may be the minimum time specified in scheduling. The unit frame time may be the smallest unit in which a transport block is transmitted. The unit slot time may be the maximum transmission time for the channel associated with the DMRS included in the unit slot time. The unit frame time may be a unit time for uplink transmission power to be determined in the terminal apparatus <NUM>. The unit frame time may be referred to as a subframe. There are three types of unit frame time as follows: downlink transmission only, uplink transmission only, and a combination of uplink transmission and downlink transmission. One unit frame time is defined by, for example, the NR sampling interval (Ts), the symbol length, or an integral multiple of the unit slot time.

A transmission/reception time is a time required for a single transmission/reception. An interval between a single transmission/reception and another transmission/reception is occupied by a time (gap) in which none of physical channels and physical signals is transmitted. The terminal apparatus <NUM> should not average CSI measurements concerning different transmissions/receptions. The transmission/reception time may be referred to as TTI. One transmission/reception time is defined by, for example, the NR sampling interval (Ts), the symbol length, the unit slot time, or an integral multiple of the unit frame time.

A channel access procedure is performed to access an unlicensed channel (for example, an unlicensed band) when data transmission is performed at the base station <NUM> or the terminal apparatus <NUM>.

Channel sensing is performed once or multiple times in the channel access procedure. Determination (vacancy determination) as to whether a channel to be sensed is idle (unoccupied, available, or enable) or busy (occupied, unavailable, or disable) is made on the basis of a result of the sensing. For example, the power of the channel in a predetermined latency is sensed in the channel sensing.

Examples of the latency in the channel access procedure include a first latency, a second latency, a third latency, and a fourth latency. The first latency corresponds to a slot time. Furthermore, the third latency corresponds to a deferment time.

A slot is the unit of latency of a base station apparatus and a terminal apparatus in the channel access procedure. The slot is defined as, for example, <NUM> microseconds. In other words, the first latency corresponds to <NUM> microseconds.

A single slot is inserted at the beginning of the second latency. In other words, the second latency corresponds to a slot to which a predetermined blank time has been added. The second latency is defined as, for example, <NUM> microseconds.

A defer period defined as the third latency includes the second latency and a plurality of consecutive slots following the second latency. The number of the plurality of consecutive slots following the second latency is determined on the basis of a priority class to be used to satisfy QoS.

The fourth latency includes the second latency and a single slot following the second latency.

The base station <NUM> or the terminal apparatus <NUM> senses a predetermined channel during a period of a predetermined slot. The predetermined slot is considered idle in a case where the base station <NUM> or the terminal apparatus <NUM> detects power smaller than a predetermined power detection threshold for at least <NUM> microseconds in the period of the predetermined slot. Meanwhile, in a case where the detected power is larger than the predetermined power detection threshold, the predetermined slot is considered busy.

The channel access procedures include a first channel access procedure and a second channel access procedure. The first channel access procedure is performed by use of a plurality of slots and the defer period. Furthermore, the second channel access procedure is performed by use of the single fourth latency.

First, the first channel access procedure will be described. Steps set forth in (<NUM>) to (<NUM>) below are performed in the first channel access procedure.

Then, after step (<NUM>) is stopped in the above procedure, transmission including data is performed on the channel by use of PDSCH, PUSCH, or the like.

Note that transmission need not be performed on the channel after step (<NUM>) is stopped in the above procedure. In this case, it is possible to then perform transmission without performing the above procedure, in a case where the channel is idle in all of the slots and the defer periods immediately before transmission. Meanwhile, in a case where the channel is not idle in any of the slots and the defer periods, the process proceeds to step (<NUM>) of the above procedure after it is sensed that the channel is idle in all the slots in the added defer period.

Next, the second channel access procedure will be described. In the second channel access procedure, transmission may be performed immediately after the channel is considered idle as a result of sensing in at least the fourth latency. Meanwhile, in a case where the channel is not considered idle as a result of the sensing in at least the fourth latency, no transmission is performed.

Next, a contention window adaptive procedure will be described. A contention window CW to be used in the first channel access procedure is determined on the basis of the contention window adaptive procedure.

The value of the contention window CW is held for each priority class. Furthermore, the contention window CW takes a value between a minimum contention window and a maximum contention window. The minimum contention window and the maximum contention window are determined on the basis of the priority class.

Adjustment of the value of the contention window CW is performed prior to step (<NUM>) in the first channel access procedure. The value of the contention window CW is increased in a case where the rate of NACKs is higher than a threshold in at least a HARQ response corresponding to a reference subframe in the contention window adaptive procedure or a shared channel in a reference HARQ process. Otherwise, the value of the contention window CW is set to the minimum contention window.

The value of the contention window CW is increased on the basis of, for example, the following equation: CW = <NUM>·(CW + <NUM>) - <NUM>.

Next, a channel access procedure in downlink will be described. In a case of performing downlink transmission including PDSCH, PDCCH, and/or EPDCCH in an unlicensed channel, a base station accesses the channel to perform the downlink transmission on the basis of the first channel access procedure.

Meanwhile, in a case of performing downlink transmission not including PDSCH but including DRS in an unlicensed channel, the base station accesses the channel to perform the downlink transmission on the basis of the second channel access procedure. Note that it is preferable that the duration of the downlink transmission be smaller than <NUM> millisecond.

Next, a channel access procedure in uplink will be described. In a case where there is an instruction to perform the first channel access procedure in an uplink grant for scheduling PUSCH in an unlicensed channel, a terminal apparatus performs the first channel access procedure prior to uplink transmission including the PUSCH.

Furthermore, in a case where there is an instruction to perform the second channel access procedure in the uplink grant for scheduling PUSCH, the terminal apparatus performs the second channel access procedure prior to uplink transmission including the PUSCH.

In addition, the terminal apparatus performs the second channel access procedure for uplink transmission not including PUSCH but including SRS, prior to the uplink transmission.

Furthermore, in a case where the end of uplink transmission specified in the uplink grant is within uplink duration (UL duration), the terminal apparatus performs the second channel access procedure prior to the uplink transmission, regardless of the type of procedure specified in the uplink grant.

Moreover, in a case where uplink transmission is performed after the fourth latency following the completion of downlink transmission from the base station, the terminal apparatus performs the second channel access procedure prior to the uplink transmission.

Grant-free based transmission refers to transmission to be performed by the terminal apparatus <NUM> by use of resources divided by an appropriate frequency axis and time axis, without receiving a resource allocation (grant) from the base station <NUM>. Power saving of the terminal apparatus <NUM> and low-delay communication due to a reduction in signaling overhead can be cited as the main purposes of the grant-free based transmission. In the conventional grant based transmission, the base station <NUM> notifies the terminal apparatus <NUM> of a resource to be used in downlink/uplink. As a result, it is possible to perform communication without causing resource contention with another terminal apparatus <NUM>. Meanwhile, the conventional grant based transmission involves signaling overhead due to this notification.

<FIG> is a flowchart showing an example of grant based transmission. For example, in a case of grant based transmission as shown in <FIG>, when initial connection establishment or connection re-establishment is performed between the base station <NUM> and the terminal apparatus <NUM> (step S11), the terminal apparatus <NUM> transmits a scheduling request (SR) to the base station <NUM> (step S12). The base station <NUM> provides notification of (grants) resource allocation, MCS, and the like to the terminal apparatus <NUM> (step <NUM>). The terminal apparatus <NUM> transmits data to the base station <NUM> by using an allocated resource (step <NUM>). The base station <NUM> returns ACK or NACK to the terminal apparatus <NUM> (step <NUM>).

The terminal apparatus <NUM> transmits data by using the resource allocated by the base station <NUM>, the MCS, and the like. This generates signaling overhead corresponding to step S13 (and also signaling overhead corresponding to step S12 in some cases). Such signaling overhead is reduced in grant-free based transmission.

<FIG> is a flowchart showing an example of grant-free based transmission. For example, in a case of grant-free based transmission as shown in <FIG>, when initial connection establishment or connection re-establishment is performed between the base station <NUM> and the terminal apparatus <NUM> (step S21), the terminal apparatus <NUM> transmits data to the base station <NUM> by using an arbitrarily selected resource (step <NUM>). The base station <NUM> returns ACK or NACK to the terminal apparatus <NUM> (step <NUM>).

Grant-free based transmission as shown in <FIG> implements communication without the processes of steps S12 and S13 in <FIG>. Therefore, grant-free based transmission, which does not involve notification of resource allocation, is considered a major candidate technology in terms of power saving and low-delay communication required for next-generation communications. The terminal apparatus <NUM> may select a transmission resource in grant-free based transmission from among all available bands or from a predetermined resource pool. The resource pool may be statically determined as a specification. Furthermore, the resource pool may be specified when a connection between the base station <NUM> and the terminal apparatus <NUM> is established. In addition, the resource pool may be semi-statically or dynamically set by System Information, DCI, or the like.

Next, the following describes a practical example of data transmission and reception based on multichannel sensing according to the embodiment of the present disclosure. Note that, hereinafter, data transmission based on multichannel sensing is also referred to as "multichannel sensing transmission", and data reception based on multichannel sensing is also referred to as "multichannel sensing reception".

Multichannel sensing transmission is a method that implements data transmission as follows. Channel sensing is performed for each of different channels (including, for example, frequency resources, frequency bands, cells, beams, and the like). Then, data transmission is attempted by use of a channel that has become available earlier.

As an example, it is assumed that unlicensed bands of <NUM> and <NUM> are available. For example, assume that a plurality of channels, such as a <NUM> band and a <NUM> band, is available to a wireless communication apparatus. The conventional method allows the wireless communication apparatus to perform communication by using only one of the plurality of channels, or perform transmission/reception of different data in the respective bands. Therefore, in a case where a result of channel sensing of the unlicensed band of, for example, <NUM> shows that the unlicensed band of <NUM> remains occupied, it is necessary, in the conventional method, to suspend transmission of data to be transmitted in the <NUM> band. As a result, there are cases where transmission delay may occur in the conventional method.

Thus, in the system according to the embodiment of the present disclosure, channel sensing is simultaneously performed by use of, for example, the unlicensed band of <NUM> in addition to the unlicensed band of <NUM>, and transmission of the same data is attempted. In other words, it is possible to reduce a delay in starting transmission by performing channel sensing in both the <NUM> band and the <NUM> band, and attempting to transmit the same data on a channel that has become available earlier. This can be applied to all wireless communication links including the uplink, the downlink, and the sidelink.

Furthermore, assume that after data are transmitted on the channel that has become available earlier, the other channel becomes available. In such a case, the same or different data may be transmitted on the other channel. In addition, in a case where a plurality of channels has become available at the same time, the same or different data may be transmitted simultaneously by use of the plurality of channels. Note that in a case where the same data are transmitted on different channels, it is possible to expect improvement in error rate characteristics by applying selection diversity or combined diversity at the point of reception. Alternatively, in a case where different data are transmitted, the same data for which transmission has been attempted on the channel are discarded, and different data are to be transmitted. Furthermore, although the practical example intended for two channels has been described above, the present technology may also be applied to a case of three or more channels.

Here, a procedure in a case of data transmission based on channel sensing for a plurality of unlicensed bands will be described with reference to <FIG> is a diagram showing a flow of a series of processes in the system <NUM> according to the present embodiment. Note that <FIG> illustrates a case where channel sensing is performed in the base station <NUM> for a plurality of unlicensed bands. Furthermore, <FIG> illustrates a case where data are transmitted by use of a channel that has become available first and no data are transmitted on the other channel. Note that, as processes for controlling communication in the base station <NUM>, <FIG> individually illustrates processes of controlling communications using respective channels of a licensed band, an unlicensed band <NUM>, and an unlicensed band <NUM>.

Note that the licensed band corresponds to a band to be used in communication in which data are transmitted/received via a resource allocated by the base station <NUM> to the terminal apparatus <NUM>. In other words, some channels are occupied by the terminal apparatuses <NUM> to which these channels (in other words, resources) have been allocated in the licensed band. Meanwhile, in the unlicensed band, each channel (in other words, a resource) is shared among a plurality of the terminal apparatuses <NUM> in a range in which no contention occurs (in other words, each channel is shared under control for avoiding contention). Note that the licensed band corresponds to an example of a "second channel", and the unlicensed band corresponds to an example of a "first channel".

First, system information is transmitted from the base station <NUM> (notification unit <NUM>) to the terminal apparatus <NUM> in the cell by use of the licensed band (S101). Note that, at this time, the base station <NUM> may notify the terminal apparatus <NUM> of control information regarding data transmission using the unlicensed band. As a result, the terminal apparatus <NUM> (information acquisition unit <NUM>) can acquire, as the control information, various information for receiving data transmitted from the base station <NUM> by use of the unlicensed band.

Next, the terminal apparatus <NUM> (notification unit <NUM>) transmits an initial connection request to the base station <NUM> on the basis of the acquired system information (S103). Furthermore, as a response to the initial connection request, an initial connection response is transmitted from the base station <NUM> (notification unit <NUM>) to the terminal apparatus <NUM> (S105). Thus, a connection is established between the base station <NUM> and the terminal apparatus <NUM>.

Furthermore, in a case where the connection with the base station <NUM> is disconnected, the terminal apparatus <NUM> (notification unit <NUM>) may transmit a connection re-request to the base station <NUM> (S103). In this case, after a connection re-request response is transmitted from the base station <NUM> (notification unit <NUM>) to the terminal apparatus <NUM> (S105), a connection between the base station <NUM> and the terminal apparatus <NUM> is established again.

Note that the above-described procedure including a series of steps denoted by reference signs S101 to S105 is executed through, for example, the licensed band.

Next, the following describes a process to be performed in a case where the base station <NUM> transmits data by using either the unlicensed band <NUM> or the unlicensed band <NUM>. The base station <NUM> (determination unit <NUM>) individually performs channel sensing for the respective channels of the unlicensed band <NUM> and the unlicensed band <NUM> (S107a and S107b), and determines whether or not the channels are available for data transmission (S109a and S109b). Then, the base station <NUM> individually controls counters associated with the respective channels of the unlicensed band <NUM> and the unlicensed band <NUM> on the basis of determination results for the channels (S111a and S111b).

Specifically, in a case where the base station <NUM> determines that the unlicensed band <NUM> is available as a result of channel sensing for the unlicensed band <NUM> (S109a, YES), the base station <NUM> decrements the counter associated with the unlicensed band <NUM> (S111a). Furthermore, in a case where the base station <NUM> determines that the unlicensed band <NUM> is not available (S109a, NO), the base station <NUM> continues channel sensing until it is determined that the unlicensed band <NUM> is available (S107a).

Similarly, in a case where the base station <NUM> determines that the unlicensed band <NUM> is available as a result of channel sensing for the unlicensed band <NUM> (S109b, YES), the base station <NUM> decrements the counter associated with the unlicensed band <NUM> (S111b). Furthermore, in a case where the base station <NUM> determines that the unlicensed band <NUM> is not available (S109b, NO), the base station <NUM> continues channel sensing until it is determined that the unlicensed band <NUM> is available (S107b).

The base station <NUM> continues the above-described processes denoted by reference signs S107a to S111a and S107b to S111b until at least either of the counters associated with the unlicensed band <NUM> and the unlicensed band <NUM> indicates a value below a threshold (for example, until at least either of the counters indicates <NUM>). Then, the base station <NUM> uses, for data transmission to the terminal apparatus <NUM>, the channel associated with the counter indicating a value equal to or below the threshold (S113).

For instance, <FIG> illustrates a case where the value of the counter associated with the unlicensed band <NUM> has become equal to or below the threshold (in other words, has become <NUM>) earlier than the value of the counter associated with the unlicensed band <NUM>. In this case, the base station <NUM> (communication control unit <NUM>) transmits data to the terminal apparatus <NUM> by using the unlicensed band <NUM> (S115). Furthermore, in this case, the base station <NUM> discards data to be transmitted in the unlicensed band <NUM> (S117).

A of the procedure in the case of data transmission based on channel sensing for a plurality of unlicensed bands has been described above with reference to <FIG>.

Furthermore, multichannel sensing transmission can also be applied to grant-free transmission. As described above, grant-free transmission is a method in which the terminal apparatus <NUM> arbitrarily selects a resource from a resource pool specified by the base station <NUM>, and uses the selected resource for data transmission. Therefore, there is a possibility that resource contention between the terminal apparatus <NUM> and another terminal apparatus <NUM> may occur. Thus, it is conceivable that channel sensing is used as a means for avoiding or mitigating resource contention.

For instance, as shown in the above-described example of the case of using the unlicensed band, it is conceivable that channel sensing is performed for channels (for example, frequency resources or frequency bands) available for grant-free transmission, and grant-free transmission is performed when it becomes possible to perform transmission. The above-described multichannel sensing transmission is considered effective also in this case.

Furthermore, as another example, in a case where there is a plurality of transmission channels available to the terminal apparatus <NUM> for grant-free transmission in carrier aggregation (CA), dual connectivity, or the like, the terminal apparatus <NUM> attempts to transmit data by using the plurality of channels. Here, the terminal apparatus <NUM> performs channel sensing, and attempts to perform grant-free transmission of data on a channel that has become available earlier. This makes it possible to reduce a delay in starting transmission.

These can be applied to all the wireless communication links including the uplink and the sidelink.

Furthermore, assume that after data are transmitted on the channel that has become available earlier, the other channel becomes available. In such a case, data may be transmitted on the other channel. Note that in a case where the same data are transmitted on different channels, it is possible to expect improvement in error rate characteristics by applying selection diversity or combined diversity at the point of reception. Furthermore, although the practical example intended for two channels has been described above, the present technology may also be applied to a case of three or more channels.

Here, an example of a procedure in a case of performing grant-free transmission of data on the basis of channel sensing for a plurality of bands will be described with reference to <FIG> is a diagram showing another example of the flow of the series of processes in the system <NUM> according to the present embodiment. Note that the example shown in <FIG> illustrates a case where channel sensing is performed in the terminal apparatus <NUM> for a plurality of bands available for grant-free transmission. Furthermore, the example shown in <FIG> illustrates a case where data are transmitted by use of a channel that has become available first and no data are transmitted on the other channels. Note that, as processes for controlling communication in the terminal apparatus <NUM>, the example shown in <FIG> individually illustrates a process of establishing a connection with the base station <NUM> and respective processes of transmitting data via the plurality of bands available for grant-free transmission. Furthermore, portions related to connection establishment in the processes denoted by reference signs S201 to S205 in <FIG> are substantially similar to those in the processes denoted by reference signs S101 to S105 in <FIG>. Therefore, detailed description thereof will be omitted. In addition, the base station <NUM> may notify the terminal apparatus <NUM> of a resource pool for grant-free transmission in the process denoted by reference sign S205. Note that, hereinafter, a band available for grant-free transmission is also referred to as a "grant-free transmission band". Furthermore, in the example shown in <FIG>, the grant-free transmission band corresponds to an example of the "second channel".

For example, the terminal apparatus <NUM> (determination unit <NUM>) individually performs channel sensing for respective channels of a grant-free transmission band <NUM> and a grant-free transmission band <NUM> (S207a and S207b), and determines whether or not the channels are available for data transmission (S209a and S209b). Then, the terminal apparatus <NUM> individually controls counters associated with the respective channels of the grant-free transmission band <NUM> and the grant-free transmission band <NUM> on the basis of determination results for the channels (S211a and S211b).

Specifically, in a case where the terminal apparatus <NUM> determines that the grant-free transmission band <NUM> is available as a result of channel sensing for the grant-free transmission band <NUM> (S209a, YES), the terminal apparatus <NUM> decrements the counter associated with the grant-free transmission band <NUM> (S211a). Furthermore, in a case where the terminal apparatus <NUM> determines that the grant-free transmission band <NUM> is not available (S209a, NO), the terminal apparatus <NUM> continues channel sensing until it is determined that the grant-free transmission band <NUM> is available (S207a).

Similarly, in a case where the terminal apparatus <NUM> determines that the grant-free transmission band <NUM> is available as a result of channel sensing for the grant-free transmission band <NUM> (S209b, YES), the terminal apparatus <NUM> decrements the counter associated with the grant-free transmission band <NUM> (S211b). Furthermore, in a case where the terminal apparatus <NUM> determines that the grant-free transmission band <NUM> is not available (S209b, NO), the terminal apparatus <NUM> continues channel sensing until it is determined that the grant-free transmission band <NUM> is available (S207b).

The terminal apparatus <NUM> continues the above-described processes denoted by reference signs S107a to S111a and S107b to S111b until at least either of the counters associated with the grant-free transmission band <NUM> and the grant-free transmission band <NUM> indicates a value below a threshold (for example, until at least either of the counters indicates <NUM>). Then, the terminal apparatus <NUM> uses, for grant-free transmission of data to the base station <NUM>, the channel associated with the counter indicating a value equal to or below the threshold (S213).

For instance, the example shown in <FIG> illustrates a case where the value of the counter associated with the grant-free transmission band <NUM> has become equal to or below the threshold (in other words, has become <NUM>) earlier than the value of the counter associated with the grant-free transmission band <NUM>. In this case, the terminal apparatus <NUM> (communication control unit <NUM>) transmits data to the base station <NUM> by using the grant-free transmission band <NUM> (S215). Furthermore, in this case, the terminal apparatus <NUM> may discard data to be transmitted in the grant-free transmission band <NUM> (S217).

An example of the procedure in the case of performing grant-free transmission of data on the basis of channel sensing for a plurality of bands has been described above with reference to <FIG>.

Note that the above-described example of data transmission using unlicensed bands and example of grant-free transmission illustrate cases where channels are bands. However, the technology according to the present disclosure can similarly be applied to, for example, a case where cells or beams are different even in the same band. For instance, <FIG> shows an example of assuming dual connectivity between two base stations 100D and 100E and the single terminal apparatus <NUM>. Specifically, the example shown in <FIG> assumes as follows: a cell 10D includes the base station 100D, a cell 10E includes the base station 100E, and the same band or different bands are used in the cells 10D and 10E. In this case, a channel between the base station 100D and the terminal apparatus <NUM> and a channel between the base station 100E and the terminal apparatus <NUM> can be regarded as spatially separate channels. Therefore, even if, for example, the cell 10D and the cell 10E use the same band, there are cases where results of channel sensing may be different. In other words, channel sensing is performed for each of the channel between the base station 100D and the terminal apparatus <NUM> and the channel between the base station 100E and the terminal apparatus <NUM> both in downlink and uplink. Then, transmission is attempted on a channel that has become available earlier. As a result, it is possible to achieve communication with lower delay.

Furthermore, <FIG> shows an example of a case where data are transmitted by use of a plurality of beams. Specifically, <FIG> shows an example of a case where the base station <NUM> and the terminal apparatus <NUM> communicate by using a plurality of beams (for example, beams 20A and 20B). Here, it is assumed that the beams 20A and 20B use the same band. The beams 20A and 20B can be regarded as spatially separate channels also in this case. Therefore, there are cases where respective results of channel sensing for the beams 20A and 20B may be different. Thus, channel sensing is performed for each of the plurality of beams, and transmission is attempted on a channel that has become available earlier. As a result, it is possible to achieve communication with lower delay.

Furthermore, the present practical example can also be applied to sidelink communication such as so-called Device to Device (D2D) communication, communication via a relay (hereinafter also referred to as "relay communication"), and the like. Specifically, in a case where a plurality of channels is available both in D2D communication and relay communication, channel sensing is performed for the plurality of channels. As a result, it is possible to reduce delay as in the other practical examples described above.

For example, <FIG> shows an example of a case of assuming D2D communication between two terminal apparatuses <NUM>. In <FIG>, reference sign 20C denotes a schematic communication path in D2D communication between a terminal apparatus 200D and a terminal apparatus 200E. In other words, the terminal apparatus 200D and the terminal apparatus 200E implement D2D communication via a plurality of channels in the example shown in <FIG>. In this case, for example, channel sensing is performed for each of the plurality of channels, and transmission is attempted on a channel that has become available earlier. As a result, it is possible to achieve communication with lower delay.

Furthermore, <FIG> shows an example of a case where data are transmitted via a relay. The example corresponds to an example of a case where a relay node 100B mediates communication between the base station 100A and the terminal apparatus <NUM>. In <FIG>, reference sign 20D denotes a schematic communication path between the base station 100A and the relay node 100B. Furthermore, reference sign 20E denotes a schematic communication path between the relay node 100B and the terminal apparatus <NUM>. In other words, communication is performed via a plurality of channels on each of the communication paths 20D and 20E in the example shown in <FIG>. In this case, for example, channel sensing is performed for each of the plurality of channels, and transmission is attempted on a channel that has become available earlier, on each of the communication paths 20D and 20E. As a result, it is possible to achieve communication with lower delay.

Furthermore, <FIG> shows an example of a case where D2D communication and relay communication are combined. In <FIG>, reference sign 20F denotes a schematic communication path between the terminal apparatus 200D and the terminal apparatus 200E operating as a relay node (hereinafter also referred to as "relay terminal 200E"). Furthermore, reference sign <NUM> denotes a schematic communication path between the relay terminal 200E and a slave terminal apparatus 200F. In other words, communication is performed via a plurality of channels on each of the communication paths 20F and <NUM> in the example shown in <FIG>. In this case, for example, channel sensing is performed for each of the plurality of channels, and transmission is attempted on a channel that has become available earlier, on each of the communication paths 20F and <NUM>. As a result, it is possible to achieve communication with lower delay.

Note that it is considered that signaling for multichannel sensing transmission is required in the above practical examples. Signaling information may be provided in notification in either the licensed band or the unlicensed band. Described below is an example of signaling required for multichannel sensing transmission or reception. Examples of signaling information include control information set forth in (<NUM>) to (<NUM>) below.

Note that the following describes details of each piece of the above-described signaling information.

In a case where multichannel sensing transmission or reception is performed, it is necessary for the base station <NUM> and the terminal apparatus <NUM> to mutually recognize whether or not the base station <NUM> or the terminal apparatus <NUM> supports multichannel sensing transmission or reception. For example, the base station <NUM> notifies the terminal apparatus <NUM> whether or not the base station <NUM> supports multichannel sensing transmission or reception, on the basis of system information block (SIB), RRC signaling, or the like. Accordingly, the terminal apparatus <NUM> can recognize that the base station <NUM> supports multichannel sensing transmission or reception, by receiving the above-described control information.

Furthermore, the terminal apparatus <NUM> can notify the base station <NUM> that the terminal apparatus <NUM> supports multichannel sensing transmission or reception, on the basis of, for example, RRC signaling or the like. At this time, whether or not multichannel sensing transmission or reception can be supported may be provided in notification in association with, for example, a UE category. For example, multichannel sensing transmission or reception may be added as one of capabilities in the UE category. Alternatively, there may exist a separate UE category supporting multichannel sensing transmission or reception.

For example, in a case of assuming downlink, the base station <NUM> performs channel sensing for two or more channels, and attempts to perform multichannel sensing transmission on a channel that has become available first. At this time, in order to receive a signal transmitted from the base station <NUM>, the terminal apparatus <NUM> needs information regarding channels possibly to be used by the base station <NUM> for multichannel sensing transmission.

As a specific example, in a case where it is assumed that the base station <NUM> can attempt multichannel sensing transmission both in the <NUM> band and the <NUM> band, it is necessary for the terminal apparatus <NUM> to know that there is a possibility that the base station <NUM> may perform multichannel sensing transmission in the <NUM> band and the <NUM> band. Therefore, the base station <NUM> notifies the terminal apparatus <NUM> of information indicating that the <NUM> band and the <NUM> band may be used for multichannel sensing transmission.

Note that the means for notification is not particularly limited. As a specific example, notification may be provided semi-statically on the basis of RRC signaling, SIB, or the like, or may be provided dynamically on the basis of DCI or the like. Furthermore, as another example, the means for notification may be determined in advance as a static specification.

Examples of control information to be provided in notification include a numerical value directly indicating a frequency band, index information corresponding to a band, enable information for multichannel sensing transmission, and the like. The numerical value directly indicating a frequency band corresponds to control information indicating the numerical value of the frequency band simply as a numerical value. Furthermore, the index information corresponding to a band corresponds to control information that defines, for example, the <NUM> band as a Oth bit and the <NUM> band as a first bit in such a way as to enable switching between ON and OFF by specifying <NUM> or <NUM> in the bit. In addition, the enable information for multichannel sensing transmission is control information that defines, for example, whether multichannel sensing transmission is performed by use of all bands possibly to be used (multichannel sensing transmission is enabled) or transmission is performed in any one of the bands possibly to be used (multichannel sensing transmission is disabled) in a case where the bands possibly to be used are determined in advance statically or semi-statically. These pieces of control information can be similarly applied to uplink, sidelink, and the like. With these pieces of control information, for example, the base station <NUM> statically, semi-statically, or dynamically specifies a band that may be used for multichannel sensing transmission, and causes the terminal apparatus <NUM> to recognize the specified band. As a result, the terminal apparatus <NUM> can perform multichannel sensing transmission by using the specified band.

In a case where the base station <NUM> and the terminal apparatus <NUM> support multichannel sensing transmission or reception, multichannel sensing transmission or reception can be performed. However, the system may be configured such that whether or not to perform multichannel sensing transmission or reception can be selectively switched even if the capability supports multichannel sensing transmission or reception. For example, it is conceivable that the base station <NUM> semi-statically notifies the terminal apparatus <NUM> that the terminal apparatus <NUM> may perform multichannel sensing transmission or reception, on the basis of SIB or RRC signaling. Furthermore, the base station <NUM> may dynamically provide the above-described notification to the terminal apparatus <NUM> on the basis of DCI or the like.

In a case where the base station <NUM> permits the terminal apparatus <NUM> to perform multichannel sensing transmission in the uplink or sidelink, on the basis of these pieces of control information, the terminal apparatus <NUM> may perform multichannel sensing transmission.

Furthermore, as another example, in a case where the base station <NUM> notifies the terminal apparatus <NUM> of the possibility that multichannel sensing transmission may be performed in the downlink, the terminal apparatus <NUM> may constantly watch a plurality of bands.

Assume that data are transmitted by use of a band that has become available first in multichannel sensing transmission. At this time, whether or not the same data are transmitted by use of the remaining bands after transmission of the data is important information in multichannel sensing transmission. For example, in a case where the same data are not transmitted and are discarded, a process of diversity reception is not necessary. Note that information as to whether to transmit or discard the same data may be statically determined in advance in specifications or the like, or may be provided in notification by semi-static or dynamic signaling.

In a case where channel sensing is performed, for example, a counter is used as described above, and it becomes possible to transmit data when the value of the counter has become equal to or below a threshold (for example, when the value of the counter has become <NUM>). Therefore, it is necessary to set a counter initial value (in other words, information regarding a transmission waiting period). Possible cases of performing channel sensing in a plurality of bands include cases set forth in (A) and (B) below.

In the case of (A), the base station <NUM> notifies the terminal apparatus <NUM> of a single counter initial value. The terminal apparatus <NUM> applies the counter initial value provided in notification to all bands to be used in multichannel sensing transmission. Meanwhile, in the case of (B), a counter initial value is provided in notification separately for each band to be used in multichannel sensing transmission.

In a case of assuming uplink in grant-base transmission, the base station <NUM> notifies the terminal apparatus <NUM> of a transmission resource, and the terminal apparatus <NUM> performs uplink transmission by using the transmission resource provided in notification after channel sensing. At this time, the base station <NUM> may notify the terminal apparatus <NUM> of a single transmission resource common to a plurality of bands or different transmission resources (here, a transmission resource refers to logical arrangement). Note that in a case of applying a transmission resource common to a plurality of bands, it is possible to reduce signaling. Meanwhile, in a case of applying different transmission resources, it is possible to change the number of resource blocks (RBs) depending on the band. Therefore, it is possible to increase the number of RBs in a case of, for example, performing wider band transmission in a high-frequency band. Moreover, it is possible to change a modulation and coding scheme to a more highly reliable one and reduce a code rate and modulation order by increasing the number of RBs.

In a case where multichannel sensing transmission is performed, it is conceivable that priority information regarding a band or resource to be used is required as the case may be. For example, as described above, it is regarded, as an effective method, to perform transmission by using a band or resource associated with a counter that has indicated a value equal to or below a threshold (for example, a value equal to <NUM>) earlier.

Meanwhile, it is also conceivable that counters for a plurality of bands or a plurality of resources may simultaneously indicate values equal to or below the threshold (for example, indicate <NUM>). At this time, in a case where no priority has been set among the plurality of bands or the plurality of resources, it is conceivable that the following operation is performed: transmission is simultaneously performed by use of the plurality of bands or the plurality of resources, and combined diversity or selection diversity is performed at a receiving side.

Furthermore, as another example, in a case where priority has been set among the plurality of bands or the plurality of resources, it is conceivable that the following operation is performed: data are transmitted by use of only a band or resource having high priority, and the data are discarded without being transmitted in the other bands or resources. In this case, it is possible to maintain a state in which a counter indicates a value equal to or below a threshold (for example, a state in which the counter continues to indicate <NUM>) by discarding data without transmitting the data. Therefore, it is possible to, for example, immediately use the relevant bands or resources for the next transmission.

Moreover, even if the next transmission data exist, the next transmission data can be intentionally held as they are without being transmitted. In this case, in a case where, for example, an ACK of data previously transmitted in another band has not been received, or in a case where a NACK has been received, it is also possible to immediately perform retransmission by using a band kept in the state in which the counter indicates a value equal to or below the threshold (for example, the state in which the counter continues to indicate <NUM>). Furthermore, as another example, even if the next transmission data does not exist, it is also possible to maintain the state in which the counter indicates a value equal to or below the threshold (for example, the state in which the counter continues to indicate <NUM>) until the next transmission data are generated, and to perform transmission immediately after the next transmission data are generated.

Furthermore, practical examples based on two axes, that is, the frequency axis and the time axis have been cited in the above description. Meanwhile, the technology according to the present disclosure can also be applied to a practical example based on three or more axes, in which an axis of another factor is taken into consideration in addition to the frequency axis and the time axis. A case of considering non-orthogonal multiple access (NOMA) in addition to frequency and time can be cited as a specific example. Note that examples of non-orthogonal axes include an interleave pattern axis, a spreading pattern axis, a scrambling pattern axis, a codebook axis, a power axis, and the like. The index or pattern of these non-orthogonal axes may also be referred to as a multiple access (MA) signature.

Furthermore, the element referred to as a "resource" in each of the above-described practical examples may also be referred to as, for example, an "MA resource" or "MA physical resource".

The technology according to the present disclosure can be applied to various products. For example, the base station <NUM> may be implemented as any type of evolved Node B (eNB) such as a macro eNB or small eNB. The small eNB may be an eNB covering a cell smaller than a macrocell, such as a pico eNB, micro eNB, or home (femto) eNB. Instead, the base station <NUM> may be implemented as another type of base station such as a Node B or base transceiver station (BTS). The base station <NUM> may include a main body (also referred to as a base station apparatus) and one or more remote radio heads (RRHs). The main body controls wireless communication. The one or more RRHs are located separately from the main body. Furthermore, various types of terminals to be described later may operate as the base stations <NUM> by performing base station functions on a temporary or semipermanent basis. Moreover, at least some of the constituent elements of the base station <NUM> may be implemented in a base station apparatus or a module for the base station apparatus.

Furthermore, the terminal apparatus <NUM> may be implemented as, for example, a mobile terminal or on-board terminal. Examples of the mobile terminal include a smartphone, a tablet personal computer (PC), a notebook PC, a portable game terminal, a portable/dongle type mobile router, a digital camera, and the like. Examples of the on-board terminal include a car navigation apparatus and the like. In addition, the terminal apparatus <NUM> may be implemented as a terminal (also referred to as a machine type communication (MTC) terminal) that performs machine to machine (M2M) communication. Furthermore, the terminal apparatus <NUM> may be implemented as a so-called low cost UE such as an MTC terminal, eMTC terminal, or NB-IoT terminal. Moreover, at least some of the constituent elements of the terminal apparatus <NUM> may be implemented in a module (for example, an integrated circuit module including a single die) to be mounted on these terminals.

<FIG> 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. An eNB <NUM> includes one or more antennas <NUM> and a base station apparatus <NUM>. Each antenna <NUM> and the base station apparatus <NUM> can be connected to each other via an RF cable.

Each of the antennas <NUM> includes a single or a plurality of antenna elements (for example, a plurality of antenna elements forming a MIMO antenna), and is used by the base station apparatus <NUM> for transmitting and receiving wireless signals. The eNB <NUM> may include a plurality of the antennas <NUM> as shown in <FIG>. The plurality of antennas <NUM> may correspond to, for example, a plurality of frequency bands to be used by the eNB <NUM>. Note that although <FIG> shows an example in which the eNB <NUM> includes the plurality of antennas <NUM>, the eNB <NUM> may include the single antenna <NUM>.

The base station apparatus <NUM> includes a controller <NUM>, a memory <NUM>, a network interface <NUM>, and a wireless communication interface <NUM>.

The controller <NUM> may be, for example, a CPU or DSP. The controller <NUM> causes various upper-layer functions of the base station apparatus <NUM> to be performed. For example, the controller <NUM> generates a data packet from data in a signal processed by the wireless communication interface <NUM>, and transfers the generated packet via the network interface <NUM>. The controller <NUM> may generate a bundled packet by bundling data from a plurality of baseband processors, and transfer the bundled packet that has been generated. Furthermore, the controller <NUM> may have a logical function of performing control such as radio resource control, radio bearer control, mobility management, admission control, or scheduling. Furthermore, the control may be performed in cooperation with neighboring eNBs or core network nodes. The memory <NUM> includes a RAM and a ROM, and stores a program to be executed by the controller <NUM> and various control data (for example, a terminal list, transmission power data, scheduling data, and the like).

The network interface <NUM> is a communication interface for connecting the base station apparatus <NUM> to a core network <NUM>. The controller <NUM> may communicate with a core network node or another eNB via the network interface <NUM>. In that case, the eNB <NUM> and the core network node or another eNB may be connected to each other via a logical interface (for example, an S1 interface or X2 interface). The network interface <NUM> may be a wired communication interface or a wireless communication interface for a wireless backhaul. In a case where the network interface <NUM> is a wireless communication interface, the network interface <NUM> may use, for wireless communication, a frequency band higher than a frequency band to be used by the wireless communication interface <NUM>.

The wireless communication interface <NUM> supports any cellular communication system such as Long Term Evolution (LTE) or LTE-Advanced, and provides a wireless connection to a terminal located in a cell of the eNB <NUM> via the antenna <NUM>. The wireless communication interface <NUM> may typically include a baseband (BB) processor <NUM>, an RF circuit <NUM>, and the like. The BB processor <NUM> may perform, for example, coding/decoding, modulation/demodulation, multiplexing/demultiplexing, and the like. The BB processor <NUM> processes various signals in each layer (for example, L1, medium access control (MAC), radio link control (RLC), and Packet Data Convergence Protocol (PDCP)). In place of the controller <NUM>, the BB processor <NUM> may have some or all of the logical functions described above. The BB processor <NUM> may be a module including a memory that stores a communication control program, a processor that executes the program, and a related circuit. The BB processor <NUM> may be configured such that it is possible to change the function of the BB processor <NUM> by updating the above-described program. Furthermore, the above-described module may be a card or blade to be inserted into a slot of the base station apparatus <NUM>, or may be a chip to be mounted on the above-described card or blade. Meanwhile, the RF circuit <NUM> may include a mixer, a filter, an amplifier, and the like. The RF circuit <NUM> transmits and receives wireless signals via the antenna <NUM>.

The wireless communication interface <NUM> may include a plurality of the BB processors <NUM> as shown in <FIG>. The plurality of BB processors <NUM> may correspond to, for example, the plurality of frequency bands to be used by the eNB <NUM>. Furthermore, the wireless communication interface <NUM> may include a plurality of the RF circuits <NUM> as shown in <FIG>. The plurality of RF circuits <NUM> may correspond to, for example, a plurality of antenna elements. Note that although <FIG> shows an example in which the wireless communication interface <NUM> includes the plurality of BB processors <NUM> and the plurality of RF circuits <NUM>, the wireless communication interface <NUM> may include the single BB processor <NUM> or the single RF circuit <NUM>.

One or more constituent elements (at least any one of the communication control unit <NUM>, the information acquisition unit <NUM>, the determination unit <NUM>, or the notification unit <NUM>) included in the processing unit <NUM> described with reference to <FIG> may be implemented in the wireless communication interface <NUM> in the eNB <NUM> shown in <FIG>. Alternatively, at least some of these constituent elements may be implemented in the controller <NUM>. As an example, the eNB <NUM> may be equipped with a module including a part (for example, the BB processor <NUM>) or all of the wireless communication interface <NUM> and/or the controller <NUM>, so that the one or more constituent elements described above may be implemented in the module. In this case, the above-described module may store a program for causing a processor to function as the one or more constituent elements (in other words, a program for causing the processor to perform the operation of the one or more constituent elements), and may execute the program. As another example, a program for causing a processor to function as the one or more constituent elements may be installed in the eNB <NUM> and executed by the wireless communication interface <NUM> (for example, the BB processor <NUM>) and/or the controller <NUM>. As described above, the eNB <NUM>, the base station apparatus <NUM>, or the above-described module may be provided as an apparatus including the one or more constituent elements. Alternatively, a program for causing a processor to function as the one or more constituent elements may be provided. Moreover, a readable recording medium on which the above-described program has been recorded may be provided.

Furthermore, the wireless communication unit <NUM> described with reference to <FIG> may be implemented in the wireless communication interface <NUM> (for example, the RF circuit <NUM>) in the eNB <NUM> shown in <FIG>. In addition, the antenna unit <NUM> may be implemented on the antenna <NUM>. Moreover, the network communication unit <NUM> may be implemented in the controller <NUM> and/or the network interface <NUM>. Furthermore, the storage unit <NUM> may be implemented in the memory <NUM>.

<FIG> is a block diagram showing a second example of the schematic configuration of the eNB to which the technology according to the present disclosure can be applied. An eNB <NUM> includes one or more antennas <NUM>, a base station apparatus <NUM>, and an RRH <NUM>. Each antenna <NUM> and the RRH <NUM> can be connected to each other via an RF cable. Furthermore, the base station apparatus <NUM> and the RRH <NUM> can be connected to each other via a high-speed line such as an optical fiber cable.

Each of the antennas <NUM> includes a single or a plurality of antenna elements (for example, a plurality of antenna elements forming a MIMO antenna), and is used by the RRH <NUM> for transmitting and receiving wireless signals. The eNB <NUM> may include a plurality of the antennas <NUM> as shown in <FIG>. The plurality of antennas <NUM> may correspond to, for example, a plurality of frequency bands to be used by the eNB <NUM>. Note that although <FIG> shows an example in which the eNB <NUM> includes the plurality of antennas <NUM>, the eNB <NUM> may include the single antenna <NUM>.

The base station apparatus <NUM> includes a controller <NUM>, a memory <NUM>, a network interface <NUM>, a wireless communication interface <NUM>, and a connection interface <NUM>. The controller <NUM>, the memory <NUM>, and the network interface <NUM> are similar to the controller <NUM>, the memory <NUM>, and the network interface <NUM> described with reference to <FIG>.

The wireless communication interface <NUM> supports any cellular communication system such as LTE or LTE-Advanced, and provides a wireless connection to a terminal located in a sector corresponding to the RRH <NUM> via the RRH <NUM> and the antenna <NUM>. The wireless communication interface <NUM> may typically include a BB processor <NUM> and the like. The BB processor <NUM> is similar to the BB processor <NUM> described with reference to <FIG> except that the BB processor <NUM> is connected to an RF circuit <NUM> of the RRH <NUM> via the connection interface <NUM>. The wireless communication interface <NUM> may include a plurality of the BB processors <NUM> as shown in <FIG>. The plurality of BB processors <NUM> may correspond to, for example, the plurality of frequency bands to be used by the eNB <NUM>. Note that although <FIG> shows an example in which the wireless communication interface <NUM> includes the plurality of BB processors <NUM>, the wireless communication interface <NUM> may include the single BB processor <NUM>.

The connection interface <NUM> is an interface for connecting the base station apparatus <NUM> (wireless communication interface <NUM>) to the RRH <NUM>. The connection interface <NUM> may be a communication module for communication on the above-described high-speed line that connects the base station apparatus <NUM> (wireless communication interface <NUM>) and the RRH <NUM>.

Furthermore, the RRH <NUM> includes a connection interface <NUM> and a wireless communication interface <NUM>.

The connection interface <NUM> is an interface for connecting the RRH <NUM> (wireless communication interface <NUM>) to the base station apparatus <NUM>. The connection interface <NUM> may be a communication module for communication on the above-described high-speed line.

The wireless communication interface <NUM> transmits and receives wireless signals via the antenna <NUM>. The wireless communication interface <NUM> may typically include the RF circuit <NUM> and the like. The RF circuit <NUM> may include a mixer, a filter, an amplifier, and the like. The RF circuit <NUM> transmits and receives wireless signals via the antenna <NUM>. The wireless communication interface <NUM> may include a plurality of the RF circuits <NUM> as shown in <FIG>. The plurality of RF circuits <NUM> may correspond to, for example, a plurality of antenna elements. Note that although <FIG> shows an example in which the wireless communication interface <NUM> includes the plurality of RF circuits <NUM>, the wireless communication interface <NUM> may include the single RF circuit <NUM>.

One or more constituent elements (at least any one of the communication control unit <NUM>, the information acquisition unit <NUM>, the determination unit <NUM>, or the notification unit <NUM>) included in the processing unit <NUM> described with reference to <FIG> may be implemented in the wireless communication interface <NUM> and/or the wireless communication interface <NUM> in the eNB <NUM> shown in <FIG>. Alternatively, at least some of these constituent elements may be implemented in the controller <NUM>. As an example, the eNB <NUM> may be equipped with a module including a part (for example, the BB processor <NUM>) or all of the wireless communication interface <NUM> and/or the controller <NUM>, so that the one or more constituent elements described above may be implemented in the module. In this case, the above-described module may store a program for causing a processor to function as the one or more constituent elements (in other words, a program for causing the processor to perform the operation of the one or more constituent elements), and may execute the program. As another example, a program for causing a processor to function as the one or more constituent elements may be installed in the eNB <NUM> and executed by the wireless communication interface <NUM> (for example, the BB processor <NUM>) and/or the controller <NUM>. As described above, the eNB <NUM>, the base station apparatus <NUM>, or the above-described module may be provided as an apparatus including the one or more constituent elements. Alternatively, a program for causing a processor to function as the one or more constituent elements may be provided. Moreover, a readable recording medium on which the above-described program has been recorded may be provided.

Furthermore, for example, the wireless communication unit <NUM> described with reference to <FIG> may be implemented in the wireless communication interface <NUM> (for example, the RF circuit <NUM>) in the eNB <NUM> shown in <FIG>. In addition, the antenna unit <NUM> may be implemented on the antenna <NUM>. Moreover, the network communication unit <NUM> may be implemented in the controller <NUM> and/or the network interface <NUM>. Furthermore, the storage unit <NUM> may be implemented in the memory <NUM>.

<FIG> is a block diagram showing an example of a schematic configuration of a smartphone <NUM> to which the technology according to the present disclosure can be applied. The smartphone <NUM> includes a processor <NUM>, a memory <NUM>, a storage <NUM>, an external connection interface <NUM>, a camera <NUM>, a sensor <NUM>, a microphone <NUM>, an input device <NUM>, a display device <NUM>, a speaker <NUM>, a wireless communication interface <NUM>, one or more antenna switches <NUM>, one or more antennas <NUM>, a bus <NUM>, a battery <NUM>, and an auxiliary controller <NUM>.

The processor <NUM> may be, for example, a CPU or a system on chip (SoC). The processor <NUM> controls functions of an application layer and other layers of the smartphone <NUM>. The memory <NUM> includes a RAM and a ROM, and stores data and a program to be executed by the processor <NUM>. The storage <NUM> may include a storage medium such as a semiconductor memory or a hard disk. The external connection interface <NUM> is an interface for connecting an external device such as a memory card or a universal serial bus (USB) device to the smartphone <NUM>.

The camera <NUM> 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 <NUM> may include, for example, a group of sensors such as a positioning sensor, a gyro sensor, a geomagnetic sensor, and an acceleration sensor. The microphone <NUM> converts voice input to the smartphone <NUM> into a voice signal. The input device <NUM> includes, for example, a touch sensor for detecting a touch on a screen of the display device <NUM>, a keypad, a keyboard, a button or switch, and the like. The input device <NUM> accepts an operation or information input from a user. The display device <NUM> includes a screen such as a liquid crystal display (LCD) or an organic light emitting diode (OLED) display, and displays an output image for the smartphone <NUM>. The speaker <NUM> converts a voice signal to be output from the smartphone <NUM> into voice.

The wireless communication interface <NUM> supports any cellular communication system such as LTE or LTE-Advanced, and performs wireless communication. The wireless communication interface <NUM> may typically include a BB processor <NUM>, an RF circuit <NUM>, and the like. The BB processor <NUM> may perform, for example, coding/decoding, modulation/demodulation, multiplexing/demultiplexing, and the like. The BB processor <NUM> performs various signal processing for wireless communication. Meanwhile, the RF circuit <NUM> may include a mixer, a filter, an amplifier, and the like. The RF circuit <NUM> transmits and receives wireless signals via the antenna <NUM>. The wireless communication interface <NUM> may be a one-chip module in which the BB processor <NUM> and the RF circuit <NUM> are integrated. The wireless communication interface <NUM> may include a plurality of the BB processors <NUM> and a plurality of the RF circuits <NUM> as shown in <FIG>. Note that although <FIG> shows an example in which the wireless communication interface <NUM> includes the plurality of BB processors <NUM> and the plurality of RF circuits <NUM>, the wireless communication interface <NUM> may include the single BB processor <NUM> or the single RF circuit <NUM>.

Moreover, in addition to the cellular communication system, the wireless communication interface <NUM> may support another type of wireless communication system such as a near field communication system, a proximity wireless communication system, or a wireless local area network (LAN) system. In that case, the wireless communication interface <NUM> may include the BB processor <NUM> and the RF circuit <NUM> for each wireless communication system.

Each of the antenna switches <NUM> causes a connection destination of the antenna <NUM> to switch between a plurality of circuits (for example, circuits for different wireless communication systems) included in the wireless communication interface <NUM>.

Each of the antennas <NUM> includes a single or a plurality of antenna elements (for example, a plurality of antenna elements forming a MIMO antenna), and is used by the wireless communication interface <NUM> for transmitting and receiving wireless signals. The smartphone <NUM> may include a plurality of the antennas <NUM> as shown in <FIG>. Note that although <FIG> shows an example in which the smartphone <NUM> includes the plurality of antennas <NUM>, the smartphone <NUM> may include the single antenna <NUM>.

Moreover, the smartphone <NUM> may include the antenna <NUM> provided for each wireless communication system. In that case, the antenna switch <NUM> may be omitted from the configuration of the smartphone <NUM>.

The bus <NUM> connects the processor <NUM>, the memory <NUM>, the storage <NUM>, the external connection interface <NUM>, the camera <NUM>, the sensor <NUM>, the microphone <NUM>, the input device <NUM>, the display device <NUM>, the speaker <NUM>, the wireless communication interface <NUM>, and the auxiliary controller <NUM> to one another. The battery <NUM> supplies electric power to each block of the smartphone <NUM> shown in <FIG> via a feed line partially shown as a broken line in the drawing. For example, the auxiliary controller <NUM> causes a minimum necessary function of the smartphone <NUM> to be performed in a sleep mode.

One or more constituent elements (at least any one of the communication control unit <NUM>, the information acquisition unit <NUM>, the determination unit <NUM>, or the notification unit <NUM>) included in the processing unit <NUM> described with reference to <FIG> may be implemented in the wireless communication interface <NUM> in the smartphone <NUM> shown in <FIG>. Alternatively, at least some of these constituent elements may be implemented in the processor <NUM> or the auxiliary controller <NUM>. As an example, the smartphone <NUM> may be equipped with a module including a part (for example, the BB processor <NUM>) or all of the wireless communication interface <NUM>, the processor <NUM>, and/or the auxiliary controller <NUM>, so that the one or more constituent elements described above may be implemented in the module. In this case, the above-described module may store a program for causing a processor to function as the one or more constituent elements (in other words, a program for causing the processor to perform the operation of the one or more constituent elements), and may execute the program. As another example, a program for causing a processor to function as the one or more constituent elements may be installed in the smartphone <NUM> and executed by the wireless communication interface <NUM> (for example, the BB processor <NUM>), the processor <NUM>, and/or the auxiliary controller <NUM>. As described above, the smartphone <NUM> or the above-described module may be provided as an apparatus including the one or more constituent elements. Alternatively, a program for causing a processor to function as the one or more constituent elements may be provided. Moreover, a readable recording medium on which the above-described program has been recorded may be provided.

Furthermore, for example, the wireless communication unit <NUM> described with reference to <FIG> may be implemented in the wireless communication interface <NUM> (for example, the RF circuit <NUM>) in the smartphone <NUM> shown in <FIG>. In addition, the antenna unit <NUM> may be implemented on the antenna <NUM>. Furthermore, the storage unit <NUM> may be implemented in the memory <NUM>.

<FIG> is a block diagram showing an example of a schematic configuration of a car navigation apparatus <NUM> to which the technology according to the present disclosure can be applied. The car navigation apparatus <NUM> includes a processor <NUM>, a memory <NUM>, a global positioning system (GPS) module <NUM>, a sensor <NUM>, a data interface <NUM>, a content player <NUM>, a storage medium interface <NUM>, an input device <NUM>, a display device <NUM>, a speaker <NUM>, a wireless communication interface <NUM>, one or more antenna switches <NUM>, one or more antennas <NUM>, and a battery <NUM>.

The processor <NUM> may be, for example, a CPU or a SoC. The processor <NUM> controls a navigation function and other functions of the car navigation apparatus <NUM>. The memory <NUM> includes a RAM and a ROM, and stores data and a program to be executed by the processor <NUM>.

The GPS module <NUM> uses GPS signals received from GPS satellites to measure the position (for example, latitude, longitude, and altitude) of the car navigation apparatus <NUM>. The sensor <NUM> may include, for example, a group of sensors such as a gyro sensor, a geomagnetic sensor, and an atmospheric pressure sensor. The data interface <NUM> is connected to, for example, an onboard network <NUM> via a terminal (not shown), and acquires data such as vehicle speed data generated on the vehicle side.

The content player <NUM> reproduces content stored in a storage medium (for example, CD or DVD) inserted in the storage medium interface <NUM>. The input device <NUM> includes, for example, a touch sensor for detecting a touch on a screen of the display device <NUM>, and a button or switch, and accepts an operation or information input from a user. The display device <NUM> includes a screen such as an LCD or an OLED display, and displays a navigation image or an image of the content being reproduced. The speaker <NUM> outputs navigation sound or sound of the content being reproduced.

Moreover, in addition to the cellular communication system, the wireless communication interface <NUM> may support another type of wireless communication system such as a near field communication system, a proximity wireless communication system, or a wireless LAN system. In that case, the wireless communication interface <NUM> may include the BB processor <NUM> and the RF circuit <NUM> for each wireless communication system.

Each of the antennas <NUM> includes a single or a plurality of antenna elements (for example, a plurality of antenna elements forming a MIMO antenna), and is used by the wireless communication interface <NUM> for transmitting and receiving wireless signals. The car navigation apparatus <NUM> may include a plurality of the antennas <NUM> as shown in <FIG>. Note that although <FIG> shows an example in which the car navigation apparatus <NUM> includes the plurality of antennas <NUM>, the car navigation apparatus <NUM> may include the single antenna <NUM>.

Moreover, the car navigation apparatus <NUM> may include the antenna <NUM> provided for each wireless communication system. In that case, the antenna switch <NUM> may be omitted from the configuration of the car navigation apparatus <NUM>.

The battery <NUM> supplies electric power to each block of the car navigation apparatus <NUM> shown in <FIG> via a feed line partially shown as a broken line in the drawing. Furthermore, the battery <NUM> stores electric power supplied from the vehicle side.

One or more constituent elements (at least any one of the communication control unit <NUM>, the information acquisition unit <NUM>, the determination unit <NUM>, or the notification unit <NUM>) included in the processing unit <NUM> described with reference to <FIG> may be implemented in the wireless communication interface <NUM> in the car navigation apparatus <NUM> shown in <FIG>. Alternatively, at least some of these constituent elements may be implemented in the processor <NUM>. As an example, the car navigation apparatus <NUM> may be equipped with a module including a part (for example, the BB processor <NUM>) or all of the wireless communication interface <NUM> and/or the processor <NUM>, so that the one or more constituent elements described above may be implemented in the module. In this case, the above-described module may store a program for causing a processor to function as the one or more constituent elements (in other words, a program for causing the processor to perform the operation of the one or more constituent elements), and may execute the program. As another example, a program for causing a processor to function as the one or more constituent elements may be installed in the car navigation apparatus <NUM> and executed by the wireless communication interface <NUM> (for example, the BB processor <NUM>) and/or the processor <NUM>. As described above, the car navigation apparatus <NUM> or the above-described module may be provided as an apparatus including the one or more constituent elements. Alternatively, a program for causing a processor to function as the one or more constituent elements may be provided. Moreover, a readable recording medium on which the above-described program has been recorded may be provided.

Furthermore, for example, the wireless communication unit <NUM> described with reference to <FIG> may be implemented in the wireless communication interface <NUM> (for example, the RF circuit <NUM>) in the car navigation apparatus <NUM> shown in <FIG>. In addition, the antenna unit <NUM> may be implemented on the antenna <NUM>. Furthermore, the storage unit <NUM> may be implemented in the memory <NUM>.

Moreover, the technology according to the present disclosure may be implemented as an onboard system (or vehicle) <NUM> including one or more blocks of the car navigation apparatus <NUM> described above, the onboard network <NUM>, and a vehicle-side module <NUM>. In other words, the onboard system (or vehicle) <NUM> may be provided as an apparatus including at least any one of the communication control unit <NUM>, the information acquisition unit <NUM>, the determination unit <NUM>, or the notification unit <NUM>. The vehicle-side module <NUM> generates vehicle-side data such as vehicle speed, engine speed, or failure information, and outputs the generated data to the onboard network <NUM>.

As described above, in the system according to the embodiment of the present disclosure, the base station <NUM> and the terminal apparatus <NUM> perform control such that data are transmitted to a transmission destination via at least any one of a plurality of channels shared in communication with each of a plurality of apparatuses. Furthermore, the base station <NUM> and the terminal apparatus <NUM> determine whether or not the plurality of channels is available for transmission of the same data. Then, the base station <NUM> and the terminal apparatus <NUM> performs control such that in a case where at least one of the plurality of channels has continued to be available for data transmission beyond a period set for the channel, data are transmitted by use of the channel.

The configuration as described above enables the base station <NUM> and the terminal apparatus <NUM> to more efficiently use the second channel shared among a plurality of apparatuses when transmitting data to a transmission destination in the system according to the present embodiment. Therefore, in the communication system according to the present embodiment, it is possible to improve the transmission efficiency of the entire system, and thus possible to implement low-delay and highly reliable communication in a more suitable manner.

Note that an example of the following case has been described above. On the basis of counter control according to the result of channel sensing, in a case where a corresponding channel has continued to be available for data transmission beyond a period set for the channel, data are transmitted by use of the channel. Meanwhile, the method based on the counter control is just an example. The method is not particularly limited as long as it is possible to determine whether or not a target channel has continued to be available for data transmission beyond a set period.

Furthermore, each detail of the description of the base station according to each embodiment described above can be similarly applied to, for example, a gNodeB (or gNB).

Although the preferred embodiment of the present disclosure has been described above in detail with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to such an example. It will be apparent to a person having ordinary skill in the art of the present disclosure that various changes or modifications can be conceived within the scope of the technical idea described in the claims.

Claim 1:
A communication apparatus (<NUM>, <NUM>) comprising:
a control unit (<NUM>, <NUM>) configured to perform control such that data are transmitted to a transmission destination via at least any one of a plurality of channels shared in communication with each of a plurality of apparatuses; and
a determination unit (<NUM>, <NUM>) configured to perform (S107, S207), individually per channel, carrier sensing of the plurality of channels and determine (S109, S209), individually per channel, whether or not the plurality of channels is available for transmission of same data,
wherein the control unit (<NUM>, <NUM>) is further configured to
- perform control such that in a case where at least one of the plurality of channels has continued to be available for data transmission beyond a period set for the channel, data are transmitted by use of the channel,
- decrement (S111), individually per channel, a counter value set for each channel of the plurality of channels on a basis of the determining (S109, S209) whether or not the respective channel is available for transmission, and
- perform (S113, S213) control such that in a case where the decremented counter value corresponding to a channel among the plurality of channels has become equal to or below a threshold, data are transmitted (S115, S215) by use of the channel, and in a case where the decremented counter value corresponding to another channel among the plurality of channels has not become equal to or below the threshold, data to be transmitted on said another channel are discarded (S117, S217).