Patent Publication Number: US-11388745-B2

Title: User terminal and radio communication method

Description:
TECHNICAL FIELD 
     The present disclosure relates to a user terminal and a radio communication method in next-generation mobile communication systems. 
     BACKGROUND ART 
     In UMTS (Universal Mobile Telecommunications System) networks, the specifications of Long Term Evolution (LTE) have been drafted for the purpose of further increasing high speed data rates, providing lower latency, and so on (see Non-Patent Literature 1). For the purpose of achieving higher capacity, further advancement of LTE (LTE Rel. 8, Rel. 9), and so on, the specifications of LTE-A (LTE-Advanced, LTE Rel. 10, Rel. 11, Rel. 12, Rel. 13) have been drafted. 
     Successor systems of LTE (also referred to as, for example, “FRA (Future Radio Access),” “5G (5th generation mobile communication system),” “5G+(plus),” “NR (New Radio),” “NX (New radio access),” “FX (Future generation radio access),” “LTE Rel. 14,” “LTE Rel. 15” (or later versions), and so on) are also under study. 
     In existing LTE systems (for example, LTE Rel. 8 to Rel. 13), a user terminal (UE (User Equipment)) transmits uplink control information (UCI) by using a UL data channel (for example, a PUSCH (Physical Uplink Shared Channel) and/or a UL control channel (for example, a PUCCH (Physical Uplink Control Channel))). 
     When transmission timing of uplink data and transmission timing of uplink control information (UCI) overlap each other, the UE performs transmission of the uplink data and the UCI by using an uplink shared channel (PUSCH). Transmission of UCI by using a PUSCH is also referred to as “UCI on PUSCH” (“piggyback on PUSCH”), “PUSCH piggyback,” and so on. 
     For example, the UCI may include retransmission control information for DL data (also referred to as a “HARQ-ACK,” an “ACK/NACK,” an “A/N,” and so on), a scheduling request (SR), and CSI (for example, periodic CSI (P-CSI), aperiodic CSI (A-CSI), and so on). 
     CITATION LIST 
     Non-Patent Literature 
     
         
         Non-Patent Literature 1: 3GPP TS 36.300 V8.12.0 “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 8),” April, 2010 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     When the UE transmits UCI by using the PUSCH (by way of piggyback), the UE needs to determine the amount of resources necessary for the UCI. The UE may control the amount of resources for UCI to be transmitted on the PUSCH, based on information used to determine the amount of resources (also referred to as “UCI resource-related information,” “beta offset,” “β offset ,” and so on). 
     For future radio communication systems (for example, NR), configuration of a plurality of sets including beta offset values for the UE is under study. 
     However, a method for the UE to specify which set is to be used among a plurality of sets has not yet been studied. If an appropriate specification method is not used, communication throughput, spectral efficiency, and so on may be deteriorated. 
     In view of this, the present disclosure has one object to provide a user terminal and a radio communication method that can prevent reduction of communication throughput and so on in UCI on PUSCH. 
     Solution to Problem 
     A user terminal according to one aspect of the present disclosure includes a transmitting section that transmits uplink data and uplink control information on an uplink shared channel, and a control section that specifies one set among a plurality of sets of beta offset values, and controls an amount of resources for transmission of the uplink control information on the uplink shared channel, based on one of the beta offset values selected from the one set. 
     Advantageous Effects of Invention 
     According to one aspect of the present disclosure, reduction of communication throughput and so on can be prevented in UCI on PUSCH. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram to show an example of correspondence (mapping) between beta offset values and certain indices of a HARQ-ACK; 
         FIG. 2  is a diagram to show an example of four sets that are configured in a case of dynamic beta offset notification; 
         FIG. 3  is a diagram to show an example of correspondence between a set designation field and start/end timing and a set of beta offset values of a PUSCH according to a first embodiment; 
         FIG. 4  is a diagram to show an example of a schematic structure of a radio communication system according to one embodiment; 
         FIG. 5  is a diagram to show an example of an overall structure of a radio base station according to one embodiment; 
         FIG. 6  is a diagram to show an example of a functional structure of the radio base station according to one embodiment; 
         FIG. 7  is a diagram to show an example of an overall structure of a user terminal according to one embodiment; 
         FIG. 8  is a diagram to show an example of a functional structure of the user terminal according to one embodiment; and 
         FIG. 9  is a diagram to show an example of a hardware structure of the radio base station and the user terminal according to one embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     When a UE transmits UCI by using a PUSCH (by way of piggyback), the UE needs to know how many resources (for example, resource elements (REs)) are necessary for the UCI. 
     The UE may receive information used to determine the amount of resources (also referred to as “UCI resource-related information,” “beta offset,” “β offset ,” and so on), and based on the beta offset, the UE may control the amount of resources for UCI to be transmitted on the PUSCH. 
     For example, the number of symbols of a HARQ-ACK piggybacked on the PUSCH (the number of coded modulation symbols of each layer) is given by Q′ of Formula 1 (in a case of non-MIMO). 
                     Q   ′     =     min   ⁢           (       ⌈       O   ·     M   sc     PUSCH   ⁢     -     ⁢   initial       ·     N   symb     PUSCH   ⁢     -     ⁢   initial       ·     β   offset   PUSCH           ∑     r   =   0       C   -   1       ⁢           ⁢     K   r         ⌉     ,     4   ·     M   sc   PUSCH         )                 (     Formula   ⁢           ⁢   1     )               
Here, M sc   PUSCH  is a bandwidth scheduled for PUSCH transmission, and is represented by the number of subcarriers, for example.
 
     Note that, in NR, “4·M sc   PUSCH ” of Formula 1 may be given by a multiplication of a certain value (for example, 1, 2, 4, or the like) and the number of subcarriers of the PUSCH (for example, “12*number of RBs”). 
     The certain value may be a value such as:
         a value in proportion to the number of DMRS (DeModulation Reference Signal) symbols incorporated into the PUSCH;   a value in proportion to the number of times of frequency hopping (the number of hops), if frequency hopping of the PUSCH is performed;   a value in proportion to the number of slots used to transmit the PUSCH, if multi-slot scheduling (or repeated transmission, TTI bundling, and so on) of the PUSCH is performed; and   a value determined based on all or a part of parameters of the number of DMRS symbols, the number of times of frequency hopping, and the number of slots of multi-slot scheduling.       

     “4·M sc   PUSCH ” of Formula 1 may be interpreted as a value based on a function f(CR) related to a coding rate (CR) of UCI. The function may be a function f(CR, above-described certain value, the number of subcarriers of PUSCH), which has arguments of the above-described certain value, the number of subcarriers of the PUSCH, or the like. 
     Based on a beta offset value, transmission power of the PUSCH including the UCI is determined. 
     A set including one or a plurality of beta offset values may be configured for a UE, using higher layer signaling (for example, RRC signaling). Here, for example, the higher layer signaling may be any one or a combination of RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, broadcast information, and the like. 
     For example, the MAC signaling may use MAC control elements (MAC CEs), MAC PDUs (Protocol Data Units), and the like. For example, the broadcast information may be master information blocks (MIBs), system information blocks (SIBs), minimum system information (RMSI (Remaining Minimum System Information)), and the like. 
     The above set may be configured for each UCI type. Here, the UCI type may correspond to the detail of UCI. For example, the UCI type may be at least one of a HARQ-ACK, an SR, CSI, a CSI type, a CSI part, and so on. 
     For example, in PUSCH piggyback of a HARQ-ACK, three beta offset values may be defined for each set. These three values may correspond to respective cases where the number of bits of a HARQ-ACK O ACK  falls within certain values (for example, (1) O ACK ≤2, (2) [3]≤O ACK ≤[11], and (3) [11]&lt;O ACK ). 
     In PUSCH piggyback of CSI, four beta offset values may be defined for each set. These four values may correspond to respective cases where the number of bits of CSI part 1 O CSI_part1  or the number of bits of CSI part 2 O CSI_part2  fall within certain values, irrespective of whether the CSI type is 1 or 2 (for example, (A) O CSI_part1 ≤[11], (B) [11]&lt;O CSI_part1 , (C) O CSI_part2 ≤[11], and (D) [11]&lt;O CSI_part2 ). 
     Note that the UE may judge the beta offset values related to UCI, based on a certain index related to the UCI.  FIG. 1  is a diagram to show an example of correspondence (mapping) between beta offset values and certain indices of a HARQ-ACK. As shown in  FIG. 1 , different beta offset values may be configured depending on a value of each index (I HAQ-ACK   offset,i  (i=1 to 3) is associated with a corresponding one of the above-described cases (1) to (3)). Note that the correspondence of the present example is merely an example, and the beta offset values may include values different from the values shown in the figure. Further, the correspondence between the beta offset values and the indices may be different for each piece of UCI. 
     Note that, in this specification, the “beta offset value” may be interpreted as an “index corresponding to the beta offset value.” 
     Incidentally, in NR, as notification methods of the above-described beta offset, a semi-static notification and a dynamic notification are under study. 
     When dynamic beta offset notification is configured for the UE and assignment of UL transmission (UL assignment) is performed using non-fallback DCI, configuration of four sets of beta offset values for the UE for each UCI type (for example, for each of a HARQ-ACK and CSI) is under study. 
     Here, for example, the non-fallback DCI may be DCI transmitted in a UE-specific search space, and may be DCI whose configuration (contents, payload, and so on) is configurable by means of UE-specific higher layer signaling (RRC signaling). 
     In contrast, fallback DCI may be DCI transmitted in a common search space, and may be DCI whose configuration is not configurable by means of UE-specific higher layer signaling. Note that the configuration (contents, payload, and so on) of the fallback DCI may also be configurable by means of UE-common higher layer signaling (for example, broadcast information, system information, and so on). 
       FIG. 2  is a diagram to show an example of four sets that are configured in a case of dynamic beta offset notification. The present example shows sets for PUSCH piggyback of a HARQ-ACK, and shows β L   X , β M   X , and β H   X  associated with a corresponding one of the above-described cases (1) to (3) with respect to set X (X=1 to 4). 
     However, a method for the UE to specify which set is to be used among a plurality of sets has not yet been studied. If an appropriate specification method is not used, communication throughput, spectral efficiency, and so on may be deteriorated. 
     In view of this, the inventors of the present invention came up with the idea of a method for dynamically specifying a set of beta offset values. 
     Embodiments according to the present invention will be described in detail with reference to the drawings as follows. The radio communication method according to each embodiment may be employed independently or may be employed in combination. 
     The following description illustrates an example in which the number of sets of beta offset values to be configured is four. However, the number is not limited to four. Further, the non-fallback DCI may be interpreted as other DCI (for example, fallback DCI). 
     The following description mainly illustrates an example of HARQ-ACK piggyback. However, it may be understood by a person skilled in the art that the present disclosure is also applicable to other UCI on PUSCH. 
     Radio Communication Method 
     First Embodiment 
     In a first embodiment, the UE specifies a set of beta offset values, based on a certain field included in non-fallback DCI (for example, a UL grant). The certain field may be referred to as a set designation field for beta offset, a set designation field, a beta offset field, a beta offset index, and so on. 
     The set designation field may be used only for designation of a set of beta offset values. A specific value (for example, “00”) of the set designation field may indicate that there is no piggyback in a scheduled PUSCH. When the set designation field indicates the specific value, the UE may use the set designation field as virtual cyclic redundancy check (V-CRC) bits for enhancing performance of detecting the non-fallback DCI. 
     The UE may use other fields included in the DCI as the set designation field, or may judge a set in combination with the set designation field. For example, when the DCI includes a DAI (Downlink Assignment Indicator (Index)) (a UL DAI or a total DAI) and the DAI indicates “00,” the UE may judge that HARQ-ACK piggyback does not occur, may ignore the set designation field, or may use the set designation field for another purpose (for example, as the V-CRC). 
     Note that the UL DAI, the total DAI, and so on may mean a DL assignment or an index indicating the number of scheduling units used to schedule DL data based on the DL assignment among scheduling units including a certain number thereof (certain group) (for example, slots, mini-slots including one or a plurality of symbols, component carriers, partial bands (BWPs), and so on). 
     Further, the set designation field may be used for designation of other parameters, as well as designation of the set of beta offset values. For example, the set designation field may correspond to start timing (for example, a start symbol) and/or end timing (for example, an end symbol) of a scheduled PUSCH (or UCI included in the PUSCH). In other words, the set designation field may be coded by joint coding with a bit field that designates start/end timing of the PUSCH. 
       FIG. 3  is a diagram to show an example of correspondence between the set designation field and the start/end timing and the set of beta offset values of a PUSCH according to the first embodiment. As the sets of beta offset values, sets shown in  FIG. 2  are assumed. 
     In the present example, set designation fields=“00,” “01,” “10,” and “11” are associated with sets 1, 2, 3, and 4, respectively. Further, each of set designation fields=“00,” “01,” “10,” and “11” is associated with a different combination of start/end symbols of the PUSCH. Note that the set designation field is not limited to be 2 bits. 
     When data scheduled by the non-fallback DCI is short TTI data (for example, URLLC (Ultra Reliable and Low Latency Communications) data), it is assumed that a transmission period (a period from start timing to end timing) of the PUSCH is relatively short (for example, approximately one or a plurality of mini-slots). 
     When data transmitted on the PUSCH is short TTI data and UCI piggybacked on the PUSCH is related to long TTI data (for example, eMBB (enhanced Mobile Broad Band) data) (for example, in a case of a HARQ-ACK for long TTI data), it is preferable that a block error rate (BLER) of the PUSCH data be reduced. Therefore, in this case, it is preferable that the beta offset values be relatively small. 
     Further, when data transmitted on the PUSCH is short TTI data and UCI piggybacked on the PUSCH is related to short TTI data (for example, in a case of a HARQ-ACK for short TTI data), it is preferable that BLERs of both of the PUSCH data and the UCI be reduced. Therefore, in this case, the beta offset values may be relatively large. 
     When data scheduled by the non-fallback DCI is a long TTI (for example, eMBB data), it is assumed that a transmission period of the PUSCH is relatively long (for example, approximately one or a plurality of slots). 
     When data transmitted on the PUSCH is long TTI data and UCI piggybacked on the PUSCH is related to long TTI data (for example, in a case of a HARQ-ACK for long TTI data), BLERs of both of the PUSCH data and the UCI may be relatively high. Therefore, in this case, it is preferable that the beta offset values be relatively small. 
     When data transmitted on the PUSCH is long TTI data and UCI piggybacked on the PUSCH is related to short TTI data (for example, in a case of a HARQ-ACK for short TTI data), it is preferable that a BLER of the UCI be reduced. Therefore, in this case, the beta offset values may be relatively large. 
     As described above, the start/end timing and the beta offset values of the PUSCH vary depending on a transmission period length of the PUSCH data (either a long TTI or a short TTI) and a transmission period length associated with the UCI multiplexed on the data. Accordingly, by designating a set of beta offset values through the use of a bit field designating the start/end timing of the PUSCH, eMBB and URLLC data can be appropriately multiplexed, for example. 
     The UE may refer to a different table for correspondence between the set designation field and the set of beta offset values, based on at least one of a transmission period length or a service type of PUSCH data and a transmission period length or a service type of UCI piggybacked on the PUSCH data. 
     Here, the service type may be, for example, eMBB, URLLC, mMTC (massive Machine Type Communication), and so on assumed in NR. 
     Note that the set designation field may be coded by joint coding with another bit field. For example, the set designation field may be coded by joint coding with a TPC (Transmit Power Control) field. 
     When the non-fallback DCI is used to schedule code block group (CBG)-based transmission (including retransmission) instead of transport block (TB)-based transmission, the set designation field may be coded by joint coding with a field indicating a CBG index, a field indicating an MCS (Modulation and Coding Scheme), a field indicating a TBS (TB size), and so on. 
     According to the first embodiment described above, the UE can appropriately specify a set of beta offset values at the time of PUSCH piggyback, based on a field of non-fallback DCI. 
     Second Embodiment 
     A second embodiment relates to a method in which a UE specifies a set of beta offset values, based on information other than a bit field of DCI. In the second embodiment, the UE may autonomously select a set of beta offset values, based on a certain condition. 
     [Whether UL Grant-Based or Not] 
     The UE may specify a set of beta offset values, based on whether transmission of the PUSCH piggybacking UCI is UL grant-based transmission or UL grant-free transmission. 
     In UL grant-based transmission, the base station transmits a downlink control channel (UL grant) indicating assignment of UL data (PUSCH) to the UE, and the UE transmits UL data in accordance with the UL grant. 
     In contrast, in UL grant-free transmission, the UE transmits UL data without receiving a UL grant for scheduling data. The UL grant-free transmission may be referred to as “UL transmission without a UL grant,” and may be defined as a type of UL SPS (Semi-Persistent Scheduling). 
     Note that UL grant-free transmission means that there is no direct UL grant on the PDCCH for performing UL data transmission, and for example, it is possible to apply RRC signaling for configuring UL grant-free transmission or apply L1 signaling for activating UL grant-free transmission. “UL grant free” is hereinafter also simply expressed as “ULGF,” “GF PUSCH,” “GF,” and so on. 
     For example, the UE may perform control to use a set of relatively small beta offset values when UCI is piggybacked in UL grant-based transmission. This is because, in a case of UL grant-based transmission, adjustment of a BLER of PUSCH data and/or piggybacked UCI can be easily controlled by adjusting the amount of scheduled resources. 
     The UE may perform control to use a set of relatively large beta offset values when UCI is piggybacked in GF transmission. This is because GF transmission is typically used for URLLC data and thus reducing a BLER of UCI is preferred. 
     [Beam] 
     The UE may specify a set of beta offset values, based on a type of a beam applied to the PUSCH piggybacking UCI. For example, the UE may specify a set of beta offset values, based on information that is used for transmit power control of the PUSCH and that is related to a beam for the PUSCH. 
     The UE may specify a set of beta offset values, based on k of Formula 2 below. 
     
       
         
           
             
               
                 
                   
                     
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     Here, PL c (k) represents downlink path loss calculated by the UE, and k represents a resource index of a downlink reference signal used to measure path loss, for example. Correspondence between a beam index (beam indication) for the PUSCH and k may be configured by means of higher layer signaling. 
     Note that the beam index for the PUSCH may be reported to the UE by means of any one or a combination of higher layer signaling (for example, RRC signaling, MAC signaling, broadcast information, or the like) and physical layer signaling (for example, DCI). 
     Further, for example, P CMAX,c (i) represents maximum transmittable power (allowed maximum transmission power) of the UE, M PUSCH,c (i) represents a transmission bandwidth (for example, the number of resource blocks) of the PUSCH, j represents an index indicating a scheduling type of the PUSCH, P 0,c (j) represents a value corresponding to target received power of the PUSCH, α c (j) represents a coefficient to be multiplied to PL c , Δ TF,c (i) represents an offset value according to a transmission format, and f c (i, l) represents a correction value based on a transmit power control (TPC (Transmit Power Control)) command (for example, a cumulative value of TPC commands, an offset amount based on a TPC command, and so on). 
     The parameters (for example, j, l, P 0,c (j), and so on) of Formula 1 may be configured for the UE by the base station. i may represent any one of certain time units, such as a slot, a mini-slot, a subframe, and a symbol. 
     [CSI Request] 
     The UE may specify a set of beta offset values, based on whether or not CSI is piggybacked on the PUSCH. For example, when CSI is piggybacked on the PUSCH, the UE may use a fixed set of beta offset values. 
     When a CSI request field of a UL grant included in a random access response (RAR) (also referred to as “message 2”) is set to trigger CSI in non-contention-based random access, the UE may judge that a set of beta offset values for CSI piggyback of message 3 is a specific set of beta offset values. 
     Note that the specific set of beta offset values may be defined in a specification, or may be configured by higher layer signaling (for example, RMSI) and so on. 
     [Logical Channel] 
     When piggybacked UCI is a HARQ-ACK, the UE may select a set of beta offset values, according to a combination of a DL data logical channel (or a service type) of the PDSCH associated with the HARQ-ACK and a UL data logical channel (or a service type) of the PUSCH piggybacking the HARQ-ACK. 
     For example, when UL data is data for eMBB and DL data associated with the HARQ-ACK is also for eMBB, the UE can select relatively large values as the beta offset values, whereas when UL data is data for URLLC and DL data associated with the HARQ-ACK is also for eMBB, the UE can select relatively small values as the beta offset values. By using such a configuration, coding rates in consideration of a target error rate according to a use case can be configured for each of the HARQ-ACK and the UL data. 
     According to the second embodiment described above, the UE can appropriately determine a set of beta offset values even when a set of beta offset values are not explicitly specified by DCI. 
     (Radio Communication System) 
     Hereinafter, a structure of a radio communication system according to one embodiment of the present disclosure will be described. In this radio communication system, the radio communication method according to each embodiment of the present disclosure described above may be used alone or may be used in combination for communication. 
       FIG. 4  is a diagram to show an example of a schematic structure of the radio communication system according to one embodiment. A radio communication system  1  can adopt carrier aggregation (CA) and/or dual connectivity (DC) to group a plurality of fundamental frequency blocks (component carriers) into one, where the system bandwidth in an LTE system (for example, 20 MHz) constitutes one unit. 
     Note that the radio communication system  1  may be referred to as “LTE (Long Term Evolution),” “LTE-A (LTE-Advanced),” “LTE-B (LTE-Beyond),” “SUPER 3G,” “IMT-Advanced,” “4G (4th generation mobile communication system),” “5G (5th generation mobile communication system),” “NR (New Radio),” “FRA (Future Radio Access),” “New-RAT (Radio Access Technology),” and so on, or may be referred to as a system implementing these. 
     The radio communication system  1  includes a radio base station  11  that forms a macro cell C 1  of a relatively wide coverage, and radio base stations  12  ( 12   a  to  12   c ) that form small cells C 2 , which are placed within the macro cell C 1  and which are narrower than the macro cell C 1 . Also, user terminals  20  are placed in the macro cell C 1  and in each small cell C 2 . The arrangement, the number, and the like of each cell and user terminal  20  are by no means limited to the aspect shown in the diagram. 
     The user terminals  20  can connect with both the radio base station  11  and the radio base stations  12 . It is assumed that the user terminals  20  use the macro cell C 1  and the small cells C 2  at the same time by means of CA or DC. The user terminals  20  can execute CA or DC by using a plurality of cells (CCs). 
     Between the user terminals  20  and the radio base station  11 , communication can be carried out by using a carrier of a relatively low frequency band (for example, 2 GHz) and a narrow bandwidth (referred to as, for example, an “existing carrier,” a “legacy carrier” and so on). Meanwhile, between the user terminals  20  and the radio base stations  12 , a carrier of a relatively high frequency band (for example, 3.5 GHz, 5 GHz, and so on) and a wide bandwidth may be used, or the same carrier as that used between the user terminals  20  and the radio base station  11  may be used. Note that the structure of the frequency band for use in each radio base station is by no means limited to these. 
     The user terminals  20  can perform communication by using time division duplex (TDD) and/or frequency division duplex (FDD) in each cell. Furthermore, in each cell (carrier), a single numerology may be employed, or a plurality of different numerologies may be employed. 
     Numerologies may be communication parameters applied to transmission and/or reception of a certain signal and/or channel, and for example, may indicate at least one of a subcarrier spacing, a bandwidth, a symbol length, a cyclic prefix length, a subframe length, a TTI length, the number of symbols per TTI, a radio frame structure, a particular filter processing performed by a transceiver in a frequency domain, a particular windowing processing performed by a transceiver in a time domain, and so on. For example, if certain physical channels use different subcarrier spacings of the OFDM symbols constituted and/or different numbers of the OFDM symbols, it may be referred to as that the numerologies are different. 
     A wired connection (for example, means in compliance with the CPRI (Common Public Radio Interface) such as an optical fiber, an X2 interface and so on) or a wireless connection may be established between the radio base station  11  and the radio base stations  12  (or between two radio base stations  12 ). 
     The radio base station  11  and the radio base stations  12  are each connected with a higher station apparatus  30 , and are connected with a core network  40  via the higher station apparatus  30 . Note that the higher station apparatus  30  may be, for example, access gateway apparatus, a radio network controller (RNC), a mobility management entity (MME) and so on, but is by no means limited to these. Also, each radio base station  12  may be connected with the higher station apparatus  30  via the radio base station  11 . 
     Note that the radio base station  11  is a radio base station having a relatively wide coverage, and may be referred to as a “macro base station,” a “central node,” an “eNB (eNodeB),” a “transmitting/receiving point” and so on. The radio base stations  12  are radio base stations having local coverages, and may be referred to as “small base stations,” “micro base stations,” “pico base stations,” “femto base stations,” “HeNBs (Home eNodeBs),” “RRHs (Remote Radio Heads),” “transmitting/receiving points” and so on. Hereinafter, the radio base stations  11  and  12  will be collectively referred to as “radio base stations  10 ,” unless specified otherwise. 
     Each of the user terminals  20  is a terminal that supports various communication schemes such as LTE and LTE-A, and may include not only mobile communication terminals (mobile stations) but stationary communication terminals (fixed stations). 
     In the radio communication system  1 , as radio access schemes, orthogonal frequency division multiple access (OFDMA) is applied to the downlink, and single carrier frequency division multiple access (SC-FDMA) and/or OFDMA is applied to the uplink. 
     OFDMA is a multi-carrier communication scheme to perform communication by dividing a frequency band into a plurality of narrow frequency bands (subcarriers) and mapping data to each subcarrier. SC-FDMA is a single carrier communication scheme to mitigate interference between terminals by dividing the system bandwidth into bands formed with one or continuous resource blocks per terminal, and allowing a plurality of terminals to use mutually different bands. Note that the uplink and downlink radio access schemes are by no means limited to the combinations of these, and other radio access schemes may be used. 
     In the radio communication system  1 , a downlink shared channel (PDSCH (Physical Downlink Shared Channel), which is used by each user terminal  20  on a shared basis, a broadcast channel (PBCH (Physical Broadcast Channel)), downlink L1/L2 control channels and so on, are used as downlink channels. User data, higher layer control information, SIBs (System Information Blocks) and so on are communicated on the PDSCH. The MIBs (Master Information Blocks) are communicated on the PBCH. 
     The downlink L1/L2 control channels include a PDCCH (Physical Downlink Control Channel), an EPDCCH (Enhanced Physical Downlink Control Channel), a PCFICH (Physical Control Format Indicator Channel), a PHICH (Physical Hybrid-ARQ Indicator Channel) and so on. Downlink control information (DCI), including PDSCH and/or PUSCH scheduling information, and so on are communicated on the PDCCH. 
     Note that the scheduling information may be reported by the DCI. For example, the DCI scheduling DL data reception may be referred to as “DL assignment,” and the DCI scheduling UL data transmission may be referred to as “UL grant.” 
     The number of OFDM symbols to use for the PDCCH is communicated on the PCFICH. Transmission confirmation information (for example, also referred to as “retransmission control information,” “HARQ-ACK,” “ACK/NACK,” and so on) of HARQ (Hybrid Automatic Repeat reQuest) to a PUSCH is transmitted on the PHICH. The EPDCCH is frequency-division multiplexed with the PDSCH (downlink shared data channel) and used to communicate DCI and so on, like the PDCCH. 
     In the radio communication system  1 , an uplink shared channel (PUSCH (Physical Uplink Shared Channel)), which is used by each user terminal  20  on a shared basis, an uplink control channel (PUCCH (Physical Uplink Control Channel)), a random access channel (PRACH (Physical Random Access Channel)) and so on are used as uplink channels. User data, higher layer control information and so on are communicated on the PUSCH. In addition, radio quality information (CQI (Channel Quality Indicator)) of the downlink, transmission confirmation information, scheduling request (SR), and so on are transmitted on the PUCCH. By means of the PRACH, random access preambles for establishing connections with cells are communicated. 
     In the radio communication system  1 , a cell-specific reference signal (CRS), a channel state information-reference signal (CSI-RS), a demodulation reference signal (DMRS), a positioning reference signal (PRS), and so on are transmitted as downlink reference signals. In the radio communication system  1 , a measurement reference signal (SRS (Sounding Reference Signal)), a demodulation reference signal (DMRS), and so on are transmitted as uplink reference signals. Note that DMRS may be referred to as a “user terminal specific reference signal (UE-specific Reference Signal).” Transmitted reference signals are by no means limited to these. 
     (Radio Base Station) 
       FIG. 5  is a diagram to show an example of an overall structure of the radio base station according to one embodiment. A radio base station  10  includes a plurality of transmitting/receiving antennas  101 , amplifying sections  102 , transmitting/receiving sections  103 , a baseband signal processing section  104 , a call processing section  105  and a transmission line interface  106 . Note that the radio base station  10  may be configured to include one or more transmitting/receiving antennas  101 , one or more amplifying sections  102  and one or more transmitting/receiving sections  103 . 
     User data to be transmitted from the radio base station  10  to the user terminal  20  by the downlink is input from the higher station apparatus  30  to the baseband signal processing section  104 , via the transmission line interface  106 . 
     In the baseband signal processing section  104 , the user data is subjected to transmission processes, such as a PDCP (Packet Data Convergence Protocol) layer process, division and coupling of the user data, RLC (Radio Link Control) layer transmission processes such as RLC retransmission control, MAC (Medium Access Control) retransmission control (for example, an HARQ transmission process), scheduling, transport format selection, channel coding, an inverse fast Fourier transform (IFFT) process, and a precoding process, and the result is forwarded to each transmitting/receiving section  103 . Furthermore, downlink control signals are also subjected to transmission processes such as channel coding and inverse fast Fourier transform, and the result is forwarded to each transmitting/receiving section  103 . 
     The transmitting/receiving sections  103  convert baseband signals that are pre-coded and output from the baseband signal processing section  104  on a per antenna basis, to have radio frequency bands and transmit the result. The radio frequency signals having been subjected to frequency conversion in the transmitting/receiving sections  103  are amplified in the amplifying sections  102 , and transmitted from the transmitting/receiving antennas  101 . The transmitting/receiving sections  103  can be constituted with transmitters/receivers, transmitting/receiving circuits or transmitting/receiving apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. Note that each transmitting/receiving section  103  may be structured as a transmitting/receiving section in one entity, or may be constituted with a transmitting section and a receiving section. 
     Meanwhile, as for uplink signals, radio frequency signals that are received in the transmitting/receiving antennas  101  are amplified in the amplifying sections  102 . The transmitting/receiving sections  103  receive the uplink signals amplified in the amplifying sections  102 . The transmitting/receiving sections  103  convert the received signals into baseband signals through frequency conversion, and output the baseband signals to the baseband signal processing section  104 . 
     In the baseband signal processing section  104 , user data that is included in the uplink signals that are input is subjected to a fast Fourier transform (FFT) process, an inverse discrete Fourier transform (IDFT) process, error correction decoding, a MAC retransmission control receiving process, and RLC layer and PDCP layer receiving processes, and forwarded to the higher station apparatus  30  via the transmission line interface  106 . The call processing section  105  performs call processing (setting up, releasing and so on) for communication channels, manages the state of the radio base station  10 , manages the radio resources and so on. 
     The transmission line interface  106  transmits and/or receives signals to and/or from the higher station apparatus  30  via a certain interface. The transmission line interface  106  may transmit and/or receive signals (backhaul signaling) with other radio base stations  10  via an inter-base station interface (for example, an optical fiber in compliance with the CPRI (Common Public Radio Interface) and an X2 interface). 
     The transmitting/receiving sections  103  may receive UL data and uplink control information (UCI) on an uplink shared channel (for example, a PUSCH). 
     The transmitting/receiving sections  103  may transmit a transmission indication (UL grant) to the user terminal  20 . The UL grant may include a set designation field. The transmitting/receiving sections  203  may transmit information related to a beam for the PUSCH and so on to the user terminal  20 . 
       FIG. 6  is a diagram to show an example of a functional structure of the radio base station according to one embodiment of the present disclosure. Note that, the present example primarily shows functional blocks that pertain to characteristic parts of the present embodiment, and it is assumed that the radio base station  10  may include other functional blocks that are necessary for radio communication as well. 
     The baseband signal processing section  104  at least includes a control section (scheduler)  301 , a transmission signal generation section  302 , a mapping section  303 , a received signal processing section  304 , and a measurement section  305 . Note that these structures may be included in the radio base station  10 , and some or all of the structures do not need to be included in the baseband signal processing section  104 . 
     The control section (scheduler)  301  controls the whole of the radio base station  10 . The control section  301  can be constituted with a controller, a control circuit or control apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. 
     The control section  301 , for example, controls the generation of signals in the transmission signal generation section  302 , the mapping of signals by the mapping section  303 , and so on. The control section  301  controls the signal receiving processes in the received signal processing section  304 , the measurements of signals in the measurement section  305 , and so on. 
     The control section  301  controls scheduling (for example, resource allocation) of system information, a downlink data signal (for example, a signal transmitted on the PDSCH), a downlink control signal (for example, a signal transmitted on the PDCCH and/or the EPDCCH, transmission confirmation information, and so on). Based on the results of determining necessity or not of retransmission control to the uplink data signal, or the like, the control section  301  controls generation of a downlink control signal, a downlink data signal, and so on. 
     The control section  301  controls the scheduling of a synchronization signal (for example, PSS (Primary Synchronization Signal)/SSS (Secondary Synchronization Signal)), a downlink reference signal (for example, CRS, CSI-RS, DMRS), and so on. 
     The control section  301  controls scheduling of uplink data signals (for example, a signal transmitted on the PUSCH), uplink control signals (for example, a signal transmitted on the PUCCH and/or the PUSCH, transmission confirmation information, and so on), random access preambles (for example, a signal transmitted on the PRACH), uplink reference signals, and so on. 
     The control section  301  may perform control of reception of UL data on an uplink shared channel (for example, a PUSCH) and uplink control information (UCI) piggybacked on the uplink shared channel. For example, the control section  301  may specify one set among a plurality of sets of beta offset values configured for the user terminal  20 . Then, based on a beta offset value selected from the one set, the control section  301  may determine the amount of resources for UCI transmission on the PUSCH. 
     The control section  301  may perform control of transmitting a certain field included in DCI (UL grant), as the information for specifying the above one set among the above plurality of sets in the user terminal  20 . The control section  301  may associate the above certain field with start and/or end timing (symbol) of the PUSCH that is scheduled with a UL grant. 
     The transmission signal generation section  302  generates downlink signals (downlink control signals, downlink data signals, downlink reference signals and so on) based on commands from the control section  301  and outputs the downlink signals to the mapping section  303 . The transmission signal generation section  302  can be constituted with a signal generator, a signal generation circuit or signal generation apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. 
     For example, the transmission signal generation section  302  generates DL assignment to report assignment information of downlink data and/or UL grant to report assignment information of uplink data, based on commands from the control section  301 . The DL assignment and the UL grant are both DCI, and follow the DCI format. For a downlink data signal, encoding processing and modulation processing are performed in accordance with a coding rate, modulation scheme, or the like determined based on channel state information (CSI) from each user terminal  20 . 
     The mapping section  303  maps the downlink signals generated in the transmission signal generation section  302  to certain radio resources, based on commands from the control section  301 , and outputs these to the transmitting/receiving sections  103 . The mapping section  303  can be constituted with a mapper, a mapping circuit or mapping apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. 
     The received signal processing section  304  performs receiving processes (for example, demapping, demodulation, decoding and so on) of received signals that are input from the transmitting/receiving sections  103 . Here, the received signals are, for example, uplink signals that are transmitted from the user terminals  20  (uplink control signals, uplink data signals, uplink reference signals and so on). The received signal processing section  304  can be constituted with a signal processor, a signal processing circuit, or signal processing apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. 
     The received signal processing section  304  outputs the decoded information acquired through the receiving processes to the control section  301 . For example, if the received signal processing section  304  receives the PUCCH including HARQ-ACK, the received signal processing section  304  outputs the HARQ-ACK to the control section  301 . The received signal processing section  304  outputs the received signals and/or the signals after the receiving processes to the measurement section  305 . 
     The measurement section  305  conducts measurements with respect to the received signals. The measurement section  305  can be constituted with a measurer, a measurement circuit or measurement apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. 
     For example, the measurement section  305  may perform RRM (Radio Resource Management) measurement, CSI (Channel State Information) measurement, and so on, based on the received signal. The measurement section  305  may conduct measurements with respect to received power (for example, RSRP (Reference Signal Received Power)), reception quality (for example, RSRQ (Reference Signal Received Quality), SINR (Signal to Interference plus Noise Ratio), and SNR (Signal to Noise Ratio)), signal strength (for example, RSSI (Received Signal Strength Indicator)), channel information (for example, CSI), and so on. The measurement results may be output to the control section  301 . 
     (User Terminal) 
       FIG. 7  is a diagram to show an example of an overall structure of the user terminal according to one embodiment. A user terminal  20  includes a plurality of transmitting/receiving antennas  201 , amplifying sections  202 , transmitting/receiving sections  203 , a baseband signal processing section  204  and an application section  205 . Note that the user terminal  20  may be configured to include one or more transmitting/receiving antennas  201 , one or more amplifying sections  202  and one or more transmitting/receiving sections  203 . 
     Radio frequency signals that are received in the transmitting/receiving antennas  201  are amplified in the amplifying sections  202 . The transmitting/receiving sections  203  receive the downlink signals amplified in the amplifying sections  202 . The transmitting/receiving sections  203  convert the received signals into baseband signals through frequency conversion, and output the baseband signals to the baseband signal processing section  204 . The transmitting/receiving sections  203  can be constituted with transmitters/receivers, transmitting/receiving circuits or transmitting/receiving apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. Note that each transmitting/receiving section  203  may be structured as a transmitting/receiving section in one entity, or may be constituted with a transmitting section and a receiving section. 
     The baseband signal processing section  204  performs, on each input baseband signal, an FFT process, error correction decoding, a retransmission control receiving process, and so on. The downlink user data is forwarded to the application section  205 . The application section  205  performs processes related to higher layers above the physical layer and the MAC layer, and so on. In the downlink data, broadcast information may be also forwarded to the application section  205 . 
     Meanwhile, the uplink user data is input from the application section  205  to the baseband signal processing section  204 . The baseband signal processing section  204  performs a retransmission control transmission process (for example, an HARQ transmission process), channel coding, precoding, a discrete Fourier transform (DFT) process, an IFFT process and so on, and the result is forwarded to the transmitting/receiving section  203 . 
     The transmitting/receiving sections  203  convert the baseband signals output from the baseband signal processing section  204  to have radio frequency band and transmit the result. The radio frequency signals having been subjected to frequency conversion in the transmitting/receiving sections  203  are amplified in the amplifying sections  202 , and transmitted from the transmitting/receiving antennas  201 . 
     The transmitting/receiving sections  203  may transmit UL data and uplink control information (UCI) on an uplink shared channel (for example, a PUSCH). 
     The transmitting/receiving sections  203  may receive a transmission indication (UL grant) from the radio base station  10 . The UL grant may include a set designation field. The transmitting/receiving sections  203  may receive information related to a beam for the PUSCH and so on from the radio base station  10 . 
       FIG. 8  is a diagram to show an example of a functional structure of the user terminal according to one embodiment. Note that, the present example primarily shows functional blocks that pertain to characteristic parts of the present embodiment, and it is assumed that the user terminal  20  may include other functional blocks that are necessary for radio communication as well. 
     The baseband signal processing section  204  provided in the user terminal  20  at least includes a control section  401 , a transmission signal generation section  402 , a mapping section  403 , a received signal processing section  404  and a measurement section  405 . Note that these structures may be included in the user terminal  20 , and some or all of the structures do not need to be included in the baseband signal processing section  204 . 
     The control section  401  controls the whole of the user terminal  20 . The control section  401  can be constituted with a controller, a control circuit or control apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. 
     The control section  401 , for example, controls the generation of signals in the transmission signal generation section  402 , the mapping of signals by the mapping section  403 , and so on. The control section  401  controls the signal receiving processes in the received signal processing section  404 , the measurements of signals in the measurement section  405 , and so on. 
     The control section  401  acquires a downlink control signal and a downlink data signal transmitted from the radio base station  10 , from the received signal processing section  404 . The control section  401  controls generation of an uplink control signal and/or an uplink data signal, based on the results of determining necessity or not of retransmission control to a downlink control signal and/or a downlink data signal. 
     The control section  401  may perform control of transmission of UL data on an uplink shared channel (for example, a PUSCH) and uplink control information (UCI) piggybacked on the uplink shared channel. For example, the control section  401  may specify one set among a plurality of sets of beta offset values. Then, based on a beta offset value selected from the one set, the control section  401  may control the amount of resources for UCI transmission on the PUSCH. 
     The control section  401  may specify the one set among the plurality of sets, based on a certain field included in a transmission indication (a data transmission indication or a UL grant) of the PUSCH. The control section  401  may determine start and/or end timing (symbol) of the PUSCH that is scheduled with a UL grant, based on the above certain field. 
     The control section  401  may specify the one set among the plurality of sets, based on whether or not transmission of the PUSCH is performed according to the transmission indication (UL grant). 
     The control section  401  may specify the one set among the plurality of sets, based on information related to a beam for the PUSCH (for example, a beam index and/or k for transmit power control of the PUSCH). 
     If the control section  401  acquires a variety of information reported by the radio base station  10  from the received signal processing section  404 , the control section  401  may update parameters to use for control, based on the information. 
     The transmission signal generation section  402  generates uplink signals (uplink control signals, uplink data signals, uplink reference signals and so on) based on commands from the control section  401 , and outputs the uplink signals to the mapping section  403 . The transmission signal generation section  402  can be constituted with a signal generator, a signal generation circuit or signal generation apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. 
     For example, the transmission signal generation section  402  generates an uplink control signal about transmission confirmation information, the channel state information (CSI), and so on, based on commands from the control section  401 . The transmission signal generation section  402  generates uplink data signals, based on commands from the control section  401 . For example, when a UL grant is included in a downlink control signal that is reported from the radio base station  10 , the control section  401  commands the transmission signal generation section  402  to generate the uplink data signal. 
     The mapping section  403  maps the uplink signals generated in the transmission signal generation section  402  to radio resources, based on commands from the control section  401 , and outputs the result to the transmitting/receiving sections  203 . The mapping section  403  can be constituted with a mapper, a mapping circuit or mapping apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. 
     The received signal processing section  404  performs receiving processes (for example, demapping, demodulation, decoding and so on) of received signals that are input from the transmitting/receiving sections  203 . Here, the received signals are, for example, downlink signals transmitted from the radio base station  10  (downlink control signals, downlink data signals, downlink reference signals and so on). The received signal processing section  404  can be constituted with a signal processor, a signal processing circuit or signal processing apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. The received signal processing section  404  can constitute the receiving section according to the present disclosure. 
     The received signal processing section  404  outputs the decoded information acquired through the receiving processes to the control section  401 . The received signal processing section  404  outputs, for example, broadcast information, system information, RRC signaling, DCI and so on, to the control section  401 . The received signal processing section  404  outputs the received signals and/or the signals after the receiving processes to the measurement section  405 . 
     The measurement section  405  conducts measurements with respect to the received signals. The measurement section  405  can be constituted with a measurer, a measurement circuit or measurement apparatus that can be described based on general understanding of the technical field to which the present disclosure pertains. 
     For example, the measurement section  405  may perform RRM measurement, CSI measurement, and so on, based on the received signal. The measurement section  405  may conduct measurements with respect to received power (for example, RSRP), reception quality (for example, RSRQ, SINR, and SNR), signal strength (for example, RSSI), channel information (for example, CSI), and so on. The measurement results may be output to the control section  401 . 
     (Hardware Structure) 
     Note that the block diagrams that have been used to describe the above embodiments show blocks in functional units. These functional blocks (components) may be implemented in arbitrary combinations of hardware and/or software. Also, the method for implementing each functional block is not particularly limited. That is, each functional block may be realized by one piece of apparatus that is physically and/or logically aggregated, or may be realized by directly and/or indirectly connecting two or more physically and/or logically separate pieces of apparatus (via wire and/or wireless, for example) and using these plurality of pieces of apparatus. 
     For example, a radio base station, a user terminal, and so on according to one embodiment of the present disclosure may function as a computer that executes the processes of the radio communication method of the present disclosure.  FIG. 9  is a diagram to show an example of a hardware structure of the radio base station and the user terminal according to one embodiment. Physically, the above-described radio base station  10  and user terminals  20  may each be formed as computer apparatus that includes a processor  1001 , a memory  1002 , a storage  1003 , a communication apparatus  1004 , an input apparatus  1005 , an output apparatus  1006 , a bus  1007 , and so on. 
     Note that, in the following description, the word “apparatus” may be interpreted as “circuit,” “device,” “unit,” and so on. The hardware structure of the radio base station  10  and the user terminals  20  may be designed to include one or a plurality of apparatuses shown in the drawings, or may be designed not to include part of pieces of apparatus. 
     For example, although only one processor  1001  is shown, a plurality of processors may be provided. Furthermore, processes may be implemented with one processor or may be implemented at the same time, in sequence, or in different manners with one or more processors. Note that the processor  1001  may be implemented with one or more chips. 
     Each function of the radio base station  10  and the user terminals  20  is implemented, for example, by allowing certain software (programs) to be read on hardware such as the processor  1001  and the memory  1002 , and by allowing the processor  1001  to perform calculations to control communication via the communication apparatus  1004  and control reading and/or writing of data in the memory  1002  and the storage  1003 . 
     The processor  1001  controls the whole computer by, for example, running an operating system. The processor  1001  may be configured with a central processing unit (CPU), which includes interfaces with peripheral apparatus, control apparatus, computing apparatus, a register, and so on. For example, the above-described baseband signal processing section  104  ( 204 ), call processing section  105 , and so on may be implemented by the processor  1001 . 
     Furthermore, the processor  1001  reads programs (program codes), software modules, data, and so on from the storage  1003  and/or the communication apparatus  1004 , into the memory  1002 , and executes various processes according to these. As for the programs, programs to allow computers to execute at least part of the operations of the above-described embodiments are used. For example, the control section  401  of each user terminal  20  may be implemented by control programs that are stored in the memory  1002  and that operate on the processor  1001 , and other functional blocks may be implemented likewise. 
     The memory  1002  is a computer-readable recording medium, and may be constituted with, for example, at least one of a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electrically EPROM), a RAM (Random Access Memory), and other appropriate storage media. The memory  1002  may be referred to as a “register,” a “cache,” a “main memory (primary storage apparatus)” and so on. The memory  1002  can store executable programs (program codes), software modules, and/or the like for implementing a radio communication method according to one embodiment. 
     The storage  1003  is a computer-readable recording medium, and may be constituted with, for example, at least one of a flexible disk, a floppy (registered trademark) disk, a magneto-optical disk (for example, a compact disc (CD-ROM (Compact Disc ROM) and so on), a digital versatile disc, a Blu-ray (registered trademark) disk), a removable disk, a hard disk drive, a smart card, a flash memory device (for example, a card, a stick, and a key drive), a magnetic stripe, a database, a server, and other appropriate storage media. The storage  1003  may be referred to as “secondary storage apparatus.” 
     The communication apparatus  1004  is hardware (transmitting/receiving device) for allowing inter-computer communication via wired and/or wireless networks, and may be referred to as, for example, a “network device,” a “network controller,” a “network card,” a “communication module” and so on. The communication apparatus  1004  may be configured to include a high frequency switch, a duplexer, a filter, a frequency synthesizer, and so on in order to realize, for example, frequency division duplex (FDD) and/or time division duplex (TDD). For example, the above-described transmitting/receiving antennas  101  ( 201 ), amplifying sections  102  ( 202 ), transmitting/receiving sections  103  ( 203 ), transmission line interface  106 , and so on may be implemented by the communication apparatus  1004 . 
     The input apparatus  1005  is an input device that receives input from the outside (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, and so on). The output apparatus  1006  is an output device that allows sending output to the outside (for example, a display, a speaker, an LED (Light Emitting Diode) lamp, and so on). Note that the input apparatus  1005  and the output apparatus  1006  may be provided in an integrated structure (for example, a touch panel). 
     Furthermore, these types of apparatus, including the processor  1001 , the memory  1002 , and others, are connected by a bus  1007  for communicating information. The bus  1007  may be formed with a single bus, or may be formed with buses that vary between pieces of apparatus. 
     Also, the radio base station  10  and the user terminals  20  may be structured to include hardware such as a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), an FPGA (Field Programmable Gate Array), and so on, and part or all of the functional blocks may be implemented by the hardware. For example, the processor  1001  may be implemented with at least one of these pieces of hardware. 
     (Variations) 
     Note that the terminology used in this specification and/or the terminology that is needed to understand this specification may be replaced by other terms that convey the same or similar meanings. For example, “channels” and/or “symbols” may be replaced by “signals” (“signaling”). Also, “signals” may be “messages.” A reference signal may be abbreviated as an “RS,” and may be referred to as a “pilot,” a “pilot signal,” and so on, depending on which standard applies. Furthermore, a “component carrier (CC)” may be referred to as a “cell,” a “frequency carrier,” a “carrier frequency” and so on. 
     Furthermore, a radio frame may be constituted of one or a plurality of periods (frames) in the time domain. Each of one or a plurality of periods (frames) constituting a radio frame may be referred to as a “subframe.” Furthermore, a subframe may be constituted of one or a plurality of slots in the time domain. A subframe may have a fixed time length (for example, 1 ms) independent of numerology. 
     Furthermore, a slot may be constituted of one or a plurality of symbols in the time domain (OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, and so on). Furthermore, a slot may be a time unit based on numerology. A slot may include a plurality of mini-slots. Each mini-slot may be constituted of one or a plurality of symbols in the time domain. A mini-slot may be referred to as a “sub-slot.” 
     A radio frame, a subframe, a slot, a mini-slot, and a symbol all express time units in signal communication. A radio frame, a subframe, a slot, a mini-slot, and a symbol may each be called by other applicable terms. For example, one subframe may be referred to as a “transmission time interval (TTI),” a plurality of consecutive subframes may be referred to as a “TTI” or one slot or one mini-slot may be referred to as a “TTI.” That is, a subframe and/or a TTI may be a subframe (1 ms) in existing LTE, may be a shorter period than 1 ms (for example, 1 to 13 symbols), or may be a longer period than 1 ms. Note that a unit expressing TTI may be referred to as a “slot,” a “mini-slot,” and so on instead of a “subframe.” 
     Here, a TTI refers to the minimum time unit of scheduling in radio communication, for example. For example, in LTE systems, a radio base station schedules the allocation of radio resources (such as a frequency bandwidth and transmission power that are available for each user terminal) for the user terminal in TTI units. Note that the definition of TTIs is not limited to this. 
     TTIs may be transmission time units for channel-encoded data packets (transport blocks), code blocks, and/or codewords, or may be the unit of processing in scheduling, link adaptation, and so on. Note that, when TTIs are given, the time interval (for example, the number of symbols) to which transport blocks, code blocks and/or codewords are actually mapped may be shorter than the TTIs. 
     Note that, in the case where one slot or one mini-slot is referred to as a TTI, one or more TTIs (that is, one or more slots or one or more mini-slots) may be the minimum time unit of scheduling. Furthermore, the number of slots (the number of mini-slots) constituting the minimum time unit of the scheduling may be controlled. 
     A TTI having a time length of 1 ms may be referred to as a “normal TTI” (TTI in LTE Rel. 8 to Rel. 12), a “long TTI,” a “normal subframe,” a “long subframe” and so on. A TTI that is shorter than a normal TTI may be referred to as a “shortened TTI,” a “short TTI,” a “partial or fractional TTI,” a “shortened subframe,” a “short subframe,” a “mini-slot,” a “sub-slot” and so on. 
     Note that a long TTI (for example, a normal TTI, a subframe, and so on) may be interpreted as a TTI having a time length exceeding 1 ms, and a short TTI (for example, a shortened TTI and so on) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or longer than 1 ms. 
     A resource block (RB) is the unit of resource allocation in the time domain and the frequency domain, and may include one or a plurality of consecutive subcarriers in the frequency domain. Also, an RB may include one or a plurality of symbols in the time domain, and may be one slot, one mini-slot, one subframe, or one TTI in length. One TTI and one subframe each may be constituted of one or a plurality of resource blocks. Note that one or a plurality of RBs may be referred to as a “physical resource block (PRB (Physical RB)),” a “sub-carrier group (SCG),” a “resource element group (REG),” a “PRB pair,” an “RB pair” and so on. 
     Furthermore, a resource block may be constituted of one or a plurality of resource elements (REs). For example, one RE may correspond to a radio resource field of one subcarrier and one symbol. 
     Note that the above-described structures of radio frames, subframes, slots, mini-slots, symbols, and so on are merely examples. For example, structures such as the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of mini-slots included in a slot, the numbers of symbols and RBs included in a slot or a mini-slot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, and so on can be variously changed. 
     Also, the information, parameters, and so on described in this specification may be represented in absolute values or in relative values with respect to certain values, or may be represented in another corresponding information. For example, radio resources may be specified by certain indices. 
     The names used for parameters and so on in this specification are in no respect limiting. For example, since various channels (PUCCH (Physical Uplink Control Channel), PDCCH (Physical Downlink Control Channel), and so on) and information elements can be identified by any suitable names, the various names assigned to these individual channels and information elements are in no respect limiting. 
     The information, signals, and/or others described in this specification may be represented by using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, and so on, all of which may be referenced throughout the herein-contained description, may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or photons, or any combination of these. 
     Also, information, signals, and so on can be output from higher layers to lower layers and/or from lower layers to higher layers. Information, signals, and so on may be input and/or output via a plurality of network nodes. 
     The information, signals, and so on that are input and/or output may be stored in a specific location (for example, a memory) or may be managed by using a management table. The information, signals, and so on to be input and/or output can be overwritten, updated, or appended. The information, signals, and so on that are output may be deleted. The information, signals, and so on that are input may be transmitted to another apparatus. 
     Reporting of information is by no means limited to the aspects/embodiments described in this specification, and other methods may be used as well. For example, reporting of information may be implemented by using physical layer signaling (for example, downlink control information (DCI), uplink control information (UCI), higher layer signaling (for example, RRC (Radio Resource Control) signaling, broadcast information (master information block (MIB), system information blocks (SIBs), and so on), MAC (Medium Access Control) signaling and so on), and other signals and/or combinations of these. 
     Note that physical layer signaling may be referred to as “L1/L2 (Layer 1/Layer 2) control information (L1/L2 control signals),” “L1 control information (L1 control signal),” and so on. Also, RRC signaling may be referred to as an “RRC message,” and can be, for example, an RRC connection setup (RRCConnectionSetup) message, an RRC connection reconfiguration (RRCConnectionReconfiguration) message, and so on. Also, MAC signaling may be reported using, for example, MAC control elements (MAC CEs). 
     Also, reporting of certain information (for example, reporting of “X holds”) does not necessarily have to be reported explicitly, and can be reported implicitly (by, for example, not reporting this certain information or reporting another piece of information). 
     Determinations may be made in values represented by one bit (0 or 1), may be made in Boolean values that represent true or false, or may be made by comparing numerical values (for example, comparison against a certain value). 
     Software, whether referred to as “software,” “firmware,” “middleware,” “microcode,” or “hardware description language,” or called by other terms, should be interpreted broadly to mean instructions, instruction sets, code, code segments, program codes, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on. 
     Also, software, commands, information, and so on may be transmitted and received via communication media. For example, when software is transmitted from a website, a server, or other remote sources by using wired technologies (coaxial cables, optical fiber cables, twisted-pair cables, digital subscriber lines (DSL), and so on) and/or wireless technologies (infrared radiation, microwaves, and so on), these wired technologies and/or wireless technologies are also included in the definition of communication media. 
     The terms “system” and “network” as used in this specification are used interchangeably. 
     In the present specification, the terms “base station (BS),” “radio base station,” “eNB,” “gNB,” “cell,” “sector,” “cell group,” “carrier,” and “component carrier” may be used interchangeably. A base station may be referred to as a “fixed station,” “NodeB,” “eNodeB (eNB),” “access point,” “transmission point,” “receiving point,” “femto cell,” “small cell” and so on. 
     A base station can accommodate one or a plurality of (for example, three) cells (also referred to as “sectors”). When a base station accommodates a plurality of cells, the entire coverage area of the base station can be partitioned into multiple smaller areas, and each smaller area can provide communication services through base station subsystems (for example, indoor small base stations (RRHs (Remote Radio Heads))). The term “cell” or “sector” refers to part of or the entire coverage area of a base station and/or a base station subsystem that provides communication services within this coverage. 
     In the present specification, the terms “mobile station (MS),” “user terminal,” “user equipment (UE),” and “terminal” may be used interchangeably. 
     A mobile station may be referred to as, by a person skilled in the art, a “subscriber station,” “mobile unit,” “subscriber unit,” “wireless unit,” “remote unit,” “mobile device,” “wireless device,” “wireless communication device,” “remote device,” “mobile subscriber station,” “access terminal,” “mobile terminal,” “wireless terminal,” “remote terminal,” “handset,” “user agent,” “mobile client,” “client,” or some other appropriate terms in some cases. 
     Furthermore, the radio base stations in this specification may be interpreted as user terminals. For example, each aspect/embodiment of the present disclosure may be applied to a configuration in which communication between a radio base station and a user terminal is replaced with communication among a plurality of user terminals (D2D (Device-to-Device)). In this case, the user terminals  20  may have the functions of the radio base stations  10  described above. In addition, wording such as “uplink” and “downlink” may be interpreted as “side.” For example, an uplink channel may be interpreted as a side channel. 
     Likewise, the user terminals in this specification may be interpreted as radio base stations. In this case, the radio base stations  10  may have the functions of the user terminals  20  described above. 
     Actions which have been described in this specification to be performed by a base station may, in some cases, be performed by upper nodes. In a network including one or a plurality of network nodes with base stations, it is clear that various operations that are performed to communicate with terminals can be performed by base stations, one or more network nodes (for example, MMEs (Mobility Management Entities), S-GW (Serving-Gateways), and so on may be possible, but these are not limiting) other than base stations, or combinations of these. 
     The aspects/embodiments illustrated in this specification may be used individually or in combinations, which may be switched depending on the mode of implementation. The order of processes, sequences, flowcharts, and so on that have been used to describe the aspects/embodiments herein may be re-ordered as long as inconsistencies do not arise. For example, although various methods have been illustrated in this specification with various components of steps in exemplary orders, the specific orders that are illustrated herein are by no means limiting. 
     The aspects/embodiments illustrated in this specification may be applied to LTE (Long Term Evolution), LTE-A (LTE-Advanced), LTE-B (LTE-Beyond), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), New-RAT (Radio Access Technology), NR (New Radio), NX (New radio access), FX (Future generation radio access), GSM (registered trademark) (Global System for Mobile communications), CDMA 2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), systems that use other adequate radio communication methods and/or next-generation systems that are enhanced based on these. 
     The phrase “based on” (or “on the basis of”) as used in this specification does not mean “based only on” (or “only on the basis of”), unless otherwise specified. In other words, the phrase “based on” (or “on the basis of”) means both “based only on” and “based at least on” (“only on the basis of” and “at least on the basis of”). 
     Reference to elements with designations such as “first,” “second” and so on as used herein does not generally limit the quantity or order of these elements. These designations may be used herein only for convenience, as a method for distinguishing between two or more elements. Thus, reference to the first and second elements does not imply that only two elements may be employed, or that the first element must precede the second element in some way. 
     The term “judging (determining)” as used herein may encompass a wide variety of actions. For example, “judging (determining)” may be interpreted to mean making “judgments (determinations)” about calculating, computing, processing, deriving, investigating, looking up (for example, searching a table, a database, or some other data structures), ascertaining, and so on. Furthermore, “judging (determining)” may be interpreted to mean making “judgments (determinations)” about receiving (for example, receiving information), transmitting (for example, transmitting information), input, output, accessing (for example, accessing data in a memory), and so on. In addition, “judging (determining)” as used herein may be interpreted to mean making “judgments (determinations)” about resolving, selecting, choosing, establishing, comparing, and so on. In other words, “judging (determining)” may be interpreted to mean making “judgments (determinations)” about some action. 
     The terms “connected” and “coupled,” or any variation of these terms as used herein mean all direct or indirect connections or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are “connected” or “coupled” to each other. The coupling or connection between the elements may be physical, logical, or a combination thereof. For example, “connection” may be interpreted as “access.” 
     In this specification, when two elements are connected, the two elements may be considered “connected” or “coupled” to each other by using one or more electrical wires, cables and/or printed electrical connections, and, as some non-limiting and non-inclusive examples, by using electromagnetic energy having wavelengths in radio frequency regions, microwave regions, (both visible and invisible) optical regions, or the like. 
     In this specification, the phrase “A and B are different” may mean that “A and B are different from each other.” The terms “separate,” “be coupled” and so on may be interpreted similarly. 
     When terms such as “including,” “comprising,” and variations of these are used in this specification or in claims, these terms are intended to be inclusive, in a manner similar to the way the term “provide” is used. Furthermore, the term “or” as used in this specification or in claims is intended to be not an exclusive disjunction. 
     Now, although the invention according to the present disclosure has been described in detail above, it should be obvious to a person skilled in the art that the invention according to the present disclosure is by no means limited to the embodiments described in this specification. The invention according to the present disclosure can be implemented with various corrections and in various modifications, without departing from the spirit and scope of the invention defined by the recitations of claims. Consequently, the description in this specification is provided only for the purpose of explaining examples, and should by no means be construed to limit the invention according to the present disclosure in any way.