Patent Publication Number: US-10764773-B2

Title: Apparatus including an acquirer to acquire a parameter for a user relating to interference cancellation and a controller to perform measurement reporting of a cell in accordance with the parameter

Description:
TECHNICAL FIELD 
     The present invention relates to an apparatus. 
     BACKGROUND ART 
     Non-orthogonal multiple access (NOMA) has been attracting attention as a radio access technology (RAT) for a fifth generation (5G) mobile communication system following Long Term Evolution (LTE)/LTE-Advanced (LTE-A). In orthogonal frequency-division multiple access (OFDMA) and single-carrier frequency-division multiple access (SC-FDMA), which are adopted in LTE, radio resources (e.g., resource blocks) are allocated to users without overlap. These schemes are called orthogonal multiple access. In contrast, in non-orthogonal multiple access, radio resources are allocated to users with overlap. In non-orthogonal multiple access, signals of users interfere with each other, but a signal for each user is taken out by a high-precision decoding process at the reception side. Non-orthogonal multiple access, in theory, achieves higher cell communication capability than orthogonal multiple access. 
     One of radio access technologies classified into non-orthogonal multiple access is superposition coding (SPC) multiplexing/multiple access. SPC is a scheme in which signals to which different powers are allocated are multiplexed on the same radio resources. At the reception side, reception process, such as interference cancellation and/or iterative detection, is performed for reception/decoding of signals multiplexed on the same radio resource. 
     For example, PTLs 1 and 2 disclose, as SPC or a technology equivalent to SPC, techniques for setting an amplitude (or power) that allows appropriate demodulation/decoding. Moreover, for example, PTL 3 discloses a technique for enhancing successive interference cancellation (SIC) for reception of multiplexed signals. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP2003-78419A 
     Patent Literature 2: JP2003-229835A 
     Patent Literature 3: JP2013-247513A 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     When interference cancellation is performed on a user side, more preferable communication quality can be obtained in comparison to when interference cancellation is not performed, regardless of whether non-stop multiplexing/multiple access or orthogonal multiplexing/multiple access is used. Thus, cells that can be used by the user can differ depending on whether interference cancellation is performed on the user side. However, in an existing mechanism, measurement or measurement reporting that is linked to selection of a cell (for example, selection of a cell for a handover, addition of a secondary cell, or the like) is performed regardless of whether interference cancellation is performed on the user side. 
     Thus, it is desirable to provide a mechanism in which measurement or measurement reporting can be performed in consideration of interference cancellation. 
     Solution to Problem 
     According to the present disclosure, there is provided a device including: an acquisition unit configured to acquire a parameter for a user relating to interference cancellation; and a control unit configured to perform measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     According to the present disclosure, there is provided a device including: an acquisition unit configured to acquire a parameter for a user relating to interference cancellation; and a control unit configured to notify the user of the parameter, the user performing measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     Advantageous Effects of Invention 
     According to the present disclosure described above, measurement reporting can be performed in consideration of interference cancellation. Note that the effects described above are not necessarily limitative. With or in the place of the above effects, there may be achieved any one of the effects described in this specification or other effects that may be grasped from this specification. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is the first explanatory diagram for explaining an example of a process in a transmission device that supports SPC. 
         FIG. 2  is the second explanatory diagram for explaining an example of a process in a transmission device that supports SPC. 
         FIG. 3  is the third explanatory diagram for explaining an example of a process in a transmission device that supports SPC. 
         FIG. 4  is an explanatory diagram illustrating an example of the schematic configuration of a system  1  according to an embodiment of the present disclosure. 
         FIG. 5  is an explanatory diagram for describing a case in which a base station according to the embodiment is a base station of a macrocell. 
         FIG. 6  is an explanatory diagram for describing a case in which the base station according to the embodiment is a base station of a small cell. 
         FIG. 7  is a block diagram illustrating an example of a configuration of a base station according to the embodiment. 
         FIG. 8  is a block diagram illustrating an example of a configuration of a terminal device according to the embodiment. 
         FIG. 9  is an explanatory diagram for describing an example of an event state. 
         FIG. 10  is a sequence diagram showing an example of a schematic flow of an overall process for measurement reporting in accordance with a user offset. 
         FIG. 11  is a sequence diagram showing an example of a schematic flow of a process of a terminal device for measurement reporting in accordance with a user offset. 
         FIG. 12  is a sequence diagram showing an example of a schematic flow of an overall process for a decision on a handover in accordance with a user offset. 
         FIG. 13  is a sequence diagram showing an example of a schematic flow of a process of a base station for a decision on a handover in accordance with a user offset. 
         FIG. 14  is an explanatory diagram for describing an example of a relationship between a capability of interference cancellation and communication quality. 
         FIG. 15  is a sequence diagram showing an example of a schematic flow of an overall process for measurement reporting in accordance with a timer value. 
         FIG. 16  is a sequence diagram showing a first example of a schematic flow of a process of the terminal device for measurement reporting in accordance with a user offset. 
         FIG. 17  is a sequence diagram showing a first example of a schematic flow of a process of the terminal device for measurement reporting in accordance with a user offset. 
         FIG. 18  is a sequence diagram showing a first example of a schematic flow of a process for measurement in accordance with a correction value. 
         FIG. 19  is a sequence diagram showing a second example of a schematic flow of a process for measurement in accordance with a correction value. 
         FIG. 20  is a sequence diagram showing a third example of a schematic flow of a process for measurement in accordance with a correction value. 
         FIG. 21  is a sequence diagram showing an example of a schematic flow of a process for deciding a set of cancellation target cells. 
         FIG. 22  is a sequence diagram showing a fourth example of a schematic flow of a process for measurement in accordance with a correction value. 
         FIG. 23  is a sequence diagram showing a fifth example of a schematic flow of a process for measurement in accordance with a correction value. 
         FIG. 24  is an explanatory diagram for describing an example of determination in a case in which a serving cell of a user is a macrocell. 
         FIG. 25  is an explanatory diagram for describing an example of determination in a case in which a serving cell of a user is a small cell. 
         FIG. 26  is an explanatory diagram for describing a first example of determination according to a modified example. 
         FIG. 27  is an explanatory diagram for describing a second example of determination according to a modified example. 
         FIG. 28  is an explanatory diagram for describing an example of information provided to a neighboring base station for ICIC. 
         FIG. 29  is an explanatory diagram for describing an example of information provided by a neighboring base station for ICIC. 
         FIG. 30  is a sequence diagram showing an example of a schematic flow of a process for inter-cell interference coordination (ICIC). 
         FIG. 31  is a block diagram illustrating a first example of a schematic configuration of an eNB. 
         FIG. 32  is a block diagram illustrating a second example of the schematic configuration of the eNB. 
         FIG. 33  is a block diagram illustrating an example of a schematic configuration of a smartphone. 
         FIG. 34  is a block diagram illustrating an example of a schematic configuration of a car navigation device. 
     
    
    
     MODE(S) FOR CARRYING OUT THE INVENTION 
     Hereinafter, (a) preferred embodiment(s) of the present disclosure will be described in detail with reference to the appended drawings. In this specification and the appended drawings, structural elements that have substantially the same function and structure are denoted with the same reference numerals, and repeated explanation of these structural elements is omitted. 
     Note that description will be provided in the following order.
     1. SPC   2. Schematic configuration of system   3. Configuration of each device   3.1. Configuration of base station   3.2. Configuration of terminal device   4. Process flow   4.1. Measurement/measurement reporting in accordance with user parameter   4.2. Inter-cell interference coordination   5. Application examples   5.1. Application example with regard to base station   5.2. Application example with regard to terminal device   6. Conclusion   

     1. SPC 
     Processes and signals with respect to SPC will be described with reference to  FIGS. 1 to 3 . 
     (1) Processes of Transmission Device and Reception Device 
     First, processes of a transmission device and a reception device will be described. 
     (a) Process in Transmission Device 
       FIGS. 1 and 2  are explanatory diagrams for explaining an example of a process in a transmission device that supports SPC. According to  FIG. 1 , for example, bit streams (e.g., transport blocks) of a user A, a user B, and a user C are processed. For each of these bit streams, some processes (e.g., cyclic redundancy check (CRC) encoding, forward error correction (FEC) encoding, rate matching, and scrambling/interleaving, as illustrated in  FIG. 2 ) are performed and then modulation is performed. Further, layer mapping, power allocation; precoding, SPC multiplexing, resource element mapping, inverse discrete Fourier transform (IDFT)/inverse fast Fourier transform (IFFT), cyclic prefix (CP) insertion, digital-to-analog and radio frequency (RF) conversion, and the like are performed. 
     In particular, in power allocation, power is allocated to signals of the user A, the user B, and the user C, and in SPC multiplexing, the signals of the user A, the user B, and the user C are multiplexed. 
     (b) Process in Reception Device 
       FIG. 3  is an explanatory diagram for explaining an example of a process in a reception device that performs interference cancellation. According to  FIG. 4 , for example, RF and analog-to-digital conversion, CP removal, discrete Fourier transform (DFT)/fast Fourier transform (FFT), joint interference cancellation, equalization, decoding, and the like are performed. This provides bit streams (e.g., transport blocks) of the user A, the user B, and the user C. 
     (2) Transmission Signals and Reception Signals 
     (a) Downlink 
     Next, downlink transmission signals and reception signals when SPC is adopted will be described. Assumed here is a multi-cell system of heterogeneous network (HetNet), small cell enhancement (SCE), or the like. 
     (a-1) Arbitrary Signal 
     An index of a cell to be in connection with a target user u is denoted by i, and the number of transmission antennas of a base station corresponding to the cell is denoted by N TX,i . Each of the transmission antennas may also be called a transmission antenna port. A transmission signal from the cell i to the user u can be expressed in a vector form as below. 
     
       
         
           
             
               
                 
                   
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     In the above expressions, N SS,u  denotes the number of spatial transmission streams for the user u. Basically, N SS,u  is a positive integer equal to or less than N TX,i . A vector x i,u  is a spatial stream signal to the user u. Elements of this vector basically correspond to digital modulation symbols of phase shift keying (PSK), quadrature amplitude modulation (QAM), or the like. A matrix W i,u  is a precoding matrix for the user u. An element in this matrix is basically a complex number, but may be a real number. 
     A matrix P i,u  is a power allocation coefficient matrix for the user u in the cell i. In this matrix, each element is preferably a positive real number. Note that this matrix may be a diagonal matrix (i.e., a matrix whose components excluding diagonal components are zero) as below. 
     
       
         
           
             
               
                 
                   
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     If adaptive power allocation for a spatial stream is not performed, a scalar value P i,u  may be used instead of the matrix P i,u . 
     As well as the user u, another user v is present in the cell i, and a signal s i,v  of the other user v is also transmitted on the same radio resource. These signals are multiplexed by SPC. A signal s i  from the cell i after multiplexing is expressed as below. 
     
       
         
           
             
               
                 
                   
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     In the above expression, U i  denotes a set of users for which multiplexing is performed in the cell i. Also in a cell j (a cell that serves as an interference source for the user u) other than a serving cell of the user u, a transmission signal s j  is generated similarly. Such a signal is received as interference at the user side. A reception signal r u  of the user w can be expressed as below. 
     
       
         
           
             
               
                 
                   
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     In the above expressions, a matrix H i,u  is a channel response matrix for the cell i and the user u. Each element of the matrix H u,i  is basically a complex number. A vector n u  is noise included in the reception signal r u  of the user u. For example, the noise includes thermal noise and interference from another system. The average power of the noise is expressed as below.
 
σ n,u   2   [Math. 10]
 
     The reception signal r u  can also be expressed by a desired signal and another signal as below. 
     
       
         
           
             
               
                 
                   
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     In the above expression, the first term of the right side denotes a desired signal of the user w, the second term, interference in the serving cell i of the user u (called intra-cell interference, multi-user interference, multi-access interference, or the like), and the third term, interference from a cell other than the cell i (called inter-cell interference). 
     When orthogonal multiple access (e.g., OFDMA or SC-FDMA) or the like is adopted, the reception signal can be expressed as below. 
     
       
         
           
             
               
                 
                   
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     In orthogonal multiple access, no intra-cell interference occurs, and moreover, in the other cell j, a signal of the other user v is not multiplexed on the same radio resource. 
     2. SCHEMATIC CONFIGURATION OF SYSTEM 
     Now, a schematic configuration of a system  1  according to an embodiment of the present disclosure will be described with reference to  FIGS. 4 to 6 .  FIG. 4  is an explanatory diagram illustrating an example of the schematic configuration of the system  1  according to an embodiment of the present disclosure. According to  FIG. 4 , the system  1  includes a base station  100  and a terminal device  200 . Here, the terminal device  200  is also called a user. The user may also be called a user equipment (UE). Here, the UE may be a UE in LTE or LTE-A, or may generally refer to communication equipment. 
     (1) Base Station  100   
     The base station  100  is a base station of a cellular system (or mobile communication system). The base station  100  performs radio communication with a terminal device (e.g., the terminal device  200 ) located in a cell  101  of the base station  100 . For example, the base station  100  transmits a downlink signal to the terminal device, and receives an uplink signal from the terminal device. 
     (2) Terminal Device  200   
     The terminal device  200  can perform communication in a cellular system (or mobile communication system). The terminal device  200  performs radio communication with a base station (e.g., the base station  100 ) of the cellular system. For example, the terminal device  200  receives a downlink signal from the base station, and transmits an uplink signal to the base station. 
     (3) HetNet 
     (a) Case of Macrocell 
     The base station  100  is, for example, a base station of a macrocell. That is, the cell  101  is a macrocell. A specific example of this subject will be described below with reference to  FIG. 5 . 
       FIG. 5  is an explanatory diagram for describing a case in which a base station according to the embodiment is a base station of a macrocell. Referring to  FIG. 5 , the base station  100  and the terminal device  200  are shown. In this example, the base station  100  is a base station of a macrocell, and the cell  101  is a macrocell superimposed by a small cell  21 . When positioned within the small cell  21 , for example, the terminal device  200  can perform radio communication with a base station  20  of the small cell  21 . 
     (b) Case of Small Cell 
     The base station  100  may be a base station of a small cell. That is, the cell  101  may be a small cell. A specific example of this subject will be described below with respect to  FIG. 6 . 
       FIG. 6  is an explanatory diagram for describing a case in which the base station  100  is a base station of a small cell. Referring to  FIG. 6 , the base station  100  and the terminal device  200  are shown. In this example, the base station  100  is a base station of a small cell. The cell  101  is a small cell superimposing a macrocell  31 . When placed within the macrocell  31 , for example, the terminal device  200  can perform radio communication with a base station  30  of the macrocell  31 . 
     (c) Frequency Band 
     The same frequency band (for example, the same component carrier) is used in, for example, a macrocell and a small cell. That is, the same frequency band is shared between the macrocell and the small cell. 
     Alternatively, different frequency bands (for example, different component earners) may be used in a macrocell and a small cell. 
     (4) Measurement and Measurement Reporting 
     (a) Measurement 
     The terminal device  200  performs measurement with respect to a cell. The cell may be a serving cell or a neighboring cell of the terminal device  200 . 
     (a-1) Reception Power 
     The measurement includes, for example, measurement of reception power of a cell. More specifically, the measurement includes, for example, measurement of reception power of a reference signal. As an example, the measurement includes measurement of reference signal received power (RSRP). The RSRP is computed, for example, as follows.
 
RSRP Cell   =E{|r   Cell ( f,t )| 2 }
 
 f∈F   RS,Cell  
 
 t∈T   RS,Cell   [Math. 13]
 
     r cell  (f,t) indicates a reception signal of a resource element of a frequency index f and a time index t. F RS,Cell  is a set of frequency indices, and T RS,Cell  indicates a set of time indices. E{ } indicates an averaging process. RSRP may be a linear value or a decibel value. However, it is desirable for the averaging process to be an averaging process for a linear value. 
     (a-2) Communication Quality 
     The measurement includes, for example, measurement of communication quality of a cell. More specifically, the measurement includes, for example, measurement of reception quality of a reference signal. As an example, the measurement includes measurement of reference signal received quality (RSRQ). The measurement may also include measurement of a signal-to-noise ratio (SNR), a signal-to-interference-plus-noise ratio (SINR), channel state information (CSI), and/or a channel quality indicator (CQI). The RSRQ is computed, for example, as follows. 
     
       
         
           
             
               
                 
                   
                     RSRQ 
                     Cell 
                   
                   = 
                   
                     E 
                     ⁢ 
                     
                       { 
                       
                         
                           RSRP 
                           Cell 
                         
                         
                           ( 
                           
                             RSSI 
                             ⁢ 
                             
                               / 
                             
                             ⁢ 
                             N 
                           
                           ) 
                         
                       
                       } 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     14 
                   
                   ] 
                 
               
             
           
         
       
     
     N is the number of target resource blocks. RSSI is power of a reception signal across a channel bandwidth, and is computed as follows.
 
RSSI Cell   =E{|r ( t )| 2 }  [Math. 15]
 
     r(t) is a reception signal at a time index t. E{ } indicates an averaging process. RSSI may be a linear value or a decibel value. However, it is desirable for the averaging process to be an averaging process for a linear value. 
     (a-3) Reference Signal 
     The reference signal is, for example, a cell-specific reference signal (CRS or CSRS). Alternatively, the reference signal may be a demodulation reference signal (DRS or DMRS), a channel state information reference signal (CSIRS) or a positioning reference signal (PRS). 
     (b) Measurement Reporting 
     The terminal device  200  performs measurement reporting with respect to a cell. That is, the terminal device  200  reports a measurement result (or feeds a measurement result back to) a base station. The base station is, for example, a base station of a serving cell for the terminal device  200  (for example, the base station  100 ). 
     When a condition for a predetermined event is satisfied, for example, the terminal device  200  performs measurement reporting. The predetermined event is, for example, one of Events A1 to A6, B1, and B2 that are defined in the Third Generation Partnership Project (3GPP). Alternatively, the predetermined event may be another type of event. 
     The terminal device  200  may report, for example, a value of a measurement result (for example, RSRP, RSRQ, or the like), or an index corresponding to the value of the measurement result. 
     (5) Selection of Cell 
     The base station  100  selects a cell for the terminal device  200  (i.e., a user). The base station  100  selects a cell on the basis of, for example, a measurement result reported by the terminal device  200 . 
     The base station  100  selects, for example, a handover target cell of the terminal device  200 . That is, the base station  100  decides a handover of the terminal device  200  to a target cell. The handover may be a handover between base stations, or a handover between frequencies. 
     The base station  100  selects, for example, a secondary cell (or a secondary component carrier) for the terminal device  200 . That is, the base station  100  decides addition or deletion of a secondary cell for the terminal device  200 . 
     (6) Multiple Access 
     The base station  100  performs radio communication with a plurality of terminal devices through, for example, orthogonal multiple access. As an example, the orthogonal multiple access is OFDMA. As another example, the orthogonal multiple access may be frequency division multiple access (FDMA), or time division multiple access (TDMA). 
     Alternatively, the base station  100  may perform radio communication with a plurality of terminal devices through non-orthogonal multiple access. As an example, the non-orthogonal multiple access may be SPG multiple access. 
     (7) Interference Cancellation 
     When having a capability of interference cancellation, for example, the terminal device  200  removes interference from a reception signal. More specifically, for example, the terminal device  200  removes inter-cell interference from a reception signal (i.e., interference from a neighboring cell). When non-orthogonal multiple access is used, the terminal device  200  may remove intra-cell interference from a reception signal. 
     The terminal device  200  does not remove interference from a reception signal when, for example, the device has no capability of interference cancellation. 
     Note that, in the present specification, “interference cancellation” may be a technique of generating a replication of an interfering signal of a desired signal and removing the replication (i.e., interference cancellation in a narrow sense), or a technique that further includes interference suppression in addition to the interference cancellation in the narrow sense (i.e., interference cancellation in a broad sense). 
     3. CONFIGURATION OF EACH DEVICE 
     Next, configurations of the base station  100  and the terminal device  200  according to an embodiment of the present disclosure will be described with reference to  FIGS. 7 and 8 . 
     3.1. Configuration of Base Station 
     First, an example of a configuration of the base station  100  according to an embodiment of the present disclosure will be described with reference to  FIG. 7 .  FIG. 7  is a block diagram illustrating an example of the configuration of the base station  100  according to an embodiment of the present disclosure: Referring to  FIG. 7 , the base station  100  includes an antenna unit  110 , a radio communication unit  120 , a network communication unit  130 , a storage unit  140 , and a processing unit  150 . 
     (1) Antenna Unit  110   
     The antenna unit  110  radiates signals output by the radio communication unit  120  out into space as radio waves. In addition, the antenna unit  110  converts radio waves in the space into signals, and outputs the signals to the radio communication unit  120 . 
     (2) Radio Communication Unit  120   
     The radio communication unit  120  transmits and receives signals. For example, the radio communication unit  120  transmits a downlink signal to a terminal device, and receives an uplink signal from a terminal device. 
     (3) Network Communication Unit  130   
     The network communication unit  130  transmits and receives information. For example, the network communication unit  130  transmits information to other nodes, and receives information from other nodes. For example, the other nodes include another base station and a core network node. 
     (4) Storage Unit  140   
     The storage unit  140  temporarily or permanently stores a program and various data for operation of the base station  100 . 
     (5) Processing Unit  150   
     The processing unit  150  provides various functions of the base station  100 . The processing unit  150  includes an information acquisition unit  151  and a control unit  153 . Note that the processing unit  150  may further include a structural element other than these structural elements. That is, the processing unit  150  may perform operation other than the operation of these structural elements. 
     The information acquisition, unit  151  and the control unit  153  will be described below in detail. 
     3.2. Configuration of Terminal Device 
     First, an example of the configuration of the terminal device  200  according to an embodiment of the present disclosure will be described with reference to  FIG. 8 .  FIG. 8  is a block diagram illustrating the example of the configuration of the terminal device  200  according to an embodiment of the present disclosure. According to  FIG. 8 , the terminal device  200  includes an antenna unit  210 , a radio communication unit  220 , a storage unit  230 , and a processing unit  240 . 
     (1) Antenna Unit  210   
     The antenna unit  210  radiates signals output by the radio communication unit  220  out into space as radio waves. In addition, the antenna unit  210  converts radio waves in the space into signals, and outputs the signals to the radio communication unit  220 . 
     (2) Radio Communication Unit  220   
     The radio communication unit  220  transmits and receives signals. For example, the radio communication unit  220  receives a downlink signal from a base station, and transmits an uplink signal to a base station. 
     (3) Storage Unit  230   
     The storage unit  230  temporarily or permanently stores a program and various data for operation of the terminal device  200 . 
     (4) Processing Unit  240   
     The processing unit  240  provides various functions of the terminal device  200 . The processing unit  240  includes an information acquisition unit  241  and a control unit  243 . Note that the processing unit  240  may further include a structural element other than these structural elements. That is, the processing unit  240  may perform operation other than the operation of these structural elements. 
     The information acquisition unit  241  and the control unit  243  will be described below in detail. 
     4. TECHNICAL FEATURES ACCORDING TO EMBODIMENT OF PRESENT DISCLOSURE 
     Next, technical features according to an embodiment of the present disclosure will be described with reference to  FIGS. 9 to 30 ; 
     4.1. Measurement/Measurement Reporting in Accordance with User Parameter 
     According to an embodiment of the present disclosure, the terminal device  200  (the information acquisition unit  241 ) acquires a parameter for a user (which will be referred to as a user parameter hereinbelow) relating to interference cancellation. In addition, the terminal device  200  (the control unit  243 ) performs measurement or measurement reporting with respect to a cell in accordance with the user parameter. Note that the user is the terminal device  200 . 
     (1) Cell 
     The cell may be a serving cell for the user (i.e., the terminal device  200 ) or a neighboring cell for the user (i.e., the terminal device  200 ). 
     (2) Parameter 
     (a) Value Corresponding to Capability of Interference Cancellation 
     The user parameter is, for example, a value corresponding to a capability of interference cancellation of the user (i.e., the terminal device  200 ). 
     Specifically, the user parameter is greater when, for example, the user has a capability of interference cancellation, and smaller when the user has no capability of interference cancellation. 
     (b) Value Corresponding to Cell/Type of Cell 
     The user parameter is, for example, a value corresponding to the cell or a type of cell. 
     Specifically, the user parameter is greater when, for example, the cell is a small cell, and smaller when the cell is a macrocell. 
     (c) Examples of Parameter 
     As a first example, the user parameter is an offset for the user (i.e., the terminal device  200 ) relating to interference cancellation (which will be referred to as a “user offset”). The user offset is included in a condition for an event that triggers measurement reporting. The terminal device  200  (the control unit  243 ) performs measurement reporting with respect to the cell in accordance with the user offset. 
     As a second example, the user parameter is a timer value for the user (i.e., the terminal device  200 ) relating to interference cancellation, and the timer value is set for a timer to be used for measurement reporting. The terminal device  200  (the control unit  243 ) performs measurement reporting with respect to the cell in accordance with the timer value. 
     As a third example, the user parameter is a correction value for the user (i.e., the terminal device  200 ) relating to interference cancellation, and the correction value is to be used in measurement of communication quality. The terminal device  200  (the control unit  243 ) performs measurement of communication quality of the cell in accordance with the correction value. 
     Each of the examples will be described below in detail. 
     (d) Notification of Parameter 
     The base station  100  (the information acquisition unit  151 ) acquires, for example, a parameter for a user (i.e., the terminal device  200 ) relating to interference cancellation (i.e., a user parameter). Then, the base station  100  (the control unit  153 ) notifies the user (i.e., the terminal device  200 ) that performs measurement or measurement reporting with respect to the cell in accordance with the user parameter of the parameter. 
     The terminal device  200  notifies the base station  100  of, for example, a capability of interference cancellation of the terminal device  200  (i.e., a user), and the base station  100  (the processing unit  150 ) decides on a user parameter on the basis of the capability. Then, the base station  100  (the information acquisition unit  151 ) acquires the user parameter, and then the base station  100  (the control unit  153 ) notifies the terminal device  200  (i.e., the user) of the user parameter. 
     The base station  100  notifies the terminal device  200  of the user parameter through, for example, individual signaling to the terminal device  200 . Specifically, the base station  100  transmits, for example, a message including the user parameter to the terminal device  200 . 
     Note that the base station  100  may broadcast two or more user parameter candidates. Specifically, the base station  100  may transmit system information including the two or more user parameter candidates. Then, the terminal device  200  may select one of the two or more user parameter candidates as its own user parameter (for example, on the basis of the capability of the interference cancellation of the terminal device  200 ). Alternatively, the terminal device  200  may be holding its own user parameter in advance, and in this case, the base station  100  may not inform the terminal device  200  of a user parameter. 
     (3) First Example (Measurement Reporting in Accordance with User Offset) 
     As the first example, the user parameter is an offset for the user (i.e., the terminal device  200 ) relating to interference cancellation (i.e., a user offset) as described above. The user offset is included in a condition for an event that triggers measurement reporting. The terminal device  200  (the control unit  243 ) performs measurement reporting with respect to the cell in accordance with the user offset. 
     (a) User Offset 
     The user offset is, for example, a value added to a measurement result in the condition. The measurement result is, for example, the reception power of a reference signal or the reception quality of a reference signal. 
     More specifically, the user offset is, for example, included in a condition for an event that triggers measurement reporting, and added to the RSRP or the RSRQ in the condition. 
     (b) Application of Offset to Existing Event 
     The event is, for example, one of Events A1 to A6, B1, and B2 that are defined in the 3GPP. In other words, the user offset is applied to one or more events among Events A1 to A6, B1, and B2. 
     Note that, although the same reference symbols are used in events in description provided below, attention should be paid to the fact that the same reference symbols can have different values in the events. 
     (b-1) Event A1 
     Event A1 is an event in which a measurement result with respect to a serving cell exceeds a threshold value. For example, when a user offset is applied to Event A1, a condition for Event A1 is expressed as below.
 
 Ms+Ou−Hys &gt;Thresh  [Math. 16]
 
     In the above-described expression, Ms indicates a measurement result with respect to a serving cell (for example, RSRQ, RSRP, or the like), Ou indicates a user offset, Hys indicates hysteresis for avoiding frequent occurrence of the event, and Thresh indicates a threshold value. 
     As the user offset Ou becomes greater, for example, Event A1 occurs more easily (i.e., the condition for Event A1 is easier to be satisfied). On the other hand, as the user offset Ou becomes smaller, Event A1 occurs with greater difficulty (i.e., the condition for Event A1 is more difficult to be satisfied). 
     Note that, although the above-described expression represents the condition for occurrence of Event A1, a condition for end of Event A1 can be expressed as below.
 
 Ms+Ou+Hys &lt;Thresh  [Math. 17]
 
     (b-2) Event A2 
     Event A2 is an event in which a measurement result with respect to a serving cell is smaller than the threshold value. For example, when a user offset is applied to Event A2, a condition for Event A2 is expressed as below.
 
 Ms+Ou+Hys &lt;Thresh  [Math. 18]
 
     Meanings of each of the reference symbols included in the above-described expression are as described for Event A1. 
     For example, as the user offset Ou becomes greater, Event A2 occurs with greater difficulty (i.e., the condition for Event A2 is more difficult to be satisfied). On the other hand, as the user offset Ou becomes smaller, Event A2 occurs more easily (i.e., the condition for Event A1 is easier to be satisfied). 
     Note that; although the above-described expression represents the condition for occurrence of Event A2, the condition for end of Event A2 can be expressed as below.
 
 Ms+Ou−Hys &gt;Thresh  [Math. 19]
 
     (b-3) Event A3 
     Event A3 is an event in which a measurement result with respect to a neighboring cell exceeds a measurement result with respect to a serving cell by an offset. For example, when a user offset is applied to Event A3, a condition for Event A3 is expressed as below.
 
 Mn+Ofn+Ocn+Oun−Hys&gt;Mp+Ojp+Ocp+Oup+Ojf   [Math. 20]
 
     In the above-described expression, Mn indicates a measurement result with respect to a neighboring cell (for example, RSRQ, RSRP, or the like), Ofn indicates a frequency offset with respect to a frequency of the neighboring cell, Ocn indicates a cell offset with respect to the neighboring cell, Oun indicates a user offset with respect to the neighboring cell, and Hys is hysteresis for avoiding frequent occurrence of the event. 
     In addition, in the above-described expression, Mp indicates a measurement result with respect to a primary cell (for example, RSRQ, RSRP, or the like), Ofp indicates a frequency offset with respect to a frequency of the primary cell, Ocp indicates a cell offset with respect to the primary cell, and Oup indicates a user offset with respect to the primary cell. Off is an offset of Event A3. Note that a primary cell is one of serving cells. 
     As the user offset Oun with respect to the neighboring cell becomes greater, for example, Event A3 occurs more easily (i.e., the condition for Event A3 is easier to be satisfied). On the other hand, as the user offset Oup with respect to the primary cell becomes greater, Event A3 occurs with greater difficulty (i.e., the condition for Event A3 is more difficult to be satisfied). 
     Note that, although the above-described expression represents the condition for occurrence of Event A3, a condition for end of Event A3 can be expressed as below.
 
 Mn+Ofn+Ocn+Qunp+Hys&lt;Mp+Ojp+Ocp+Oup+Off  
 
     (b-4) Event A4 
     Event A4 is an event in which a measurement result with respect to a neighboring cell exceeds a threshold value. When a user offset is applied to Event A4, for example, a condition for Event A4 is expressed as below.
 
 Mn+Ofn+Qcn+Oun−Hys &gt;Thresh  [Math. 22]
 
     Meanings of each of the reference symbols included in the above-described expression are as described for Event A3. 
     As the user offset Oun becomes greater, for example, Event A4 occurs more easily (i.e., the condition for Event A4 is easier to be satisfied). On the other hand, as the user offset Oun becomes smaller, Event A4 occurs with greater difficulty (i.e., the condition for Event A4 is more difficult to be satisfied). 
     Note that, although the above-described expression represents the condition for occurrence of Event A4, a condition for end of Event A4 can be expressed as below.
 
 Mn+Ofn+Ocn+Oun+Hys &lt;Thresh  [Math. 23]
 
     (b-5) Event A5 
     Event A5 is an event in which a measurement result with respect to a serving cell is smaller than a first threshold value, and a measurement result with respect to a neighboring cell exceeds a second threshold value. For example, when a user offset is applied to Event A5, a condition for Event A5 is expressed as below.
 
 Mp+Oup+Hys &lt;Thresh1
 
 Mn+Ofn+Ocn+Oun−Hys &gt;Thresh2  [Math. 24]
 
     Meanings of each of the reference symbols included in the above-described expression are as described for Event A3 except for Thresh1 and Thresh2. Thresh1 indicates the first threshold value, and Thresh2 indicates the second threshold value. 
     As the user offset Oup with respect to a primary cell becomes greater, for example, Event A5 occurs with greater difficulty (i.e., the condition for Event A5 is more difficult to be satisfied). On the other hand, as the user offset Oun with respect to a neighboring cell becomes greater, Event A5 occurs more easily (i.e., the condition for Event A5 is easier to be satisfied). 
     Note that, although the above-described expression represents the condition for occurrence of Event A5, a condition for end of Event A5 can be expressed as below.
 
 Mp+Oup+Hys &lt;Thresh1
 
 Mn+Ofn+Ocn+Oun−Hys &gt;Thresh2  [Math. 25]
 
     (b-6) Event A6 
     Event A6 is an event in which a measurement result with respect to a neighboring cell exceeds a measurement result with respect to a secondary cell by an offset. When a user offset is applied to Event A6, for example, a condition for Event A6 is expressed as below.
 
 Mn+Ocn+Oun−Hys&gt;Ms+Ocs+Ous+Off   [Math. 26]
 
     In the above-described expression, Mn indicates a measurement result with respect to a neighboring cell (for example, RSRQ, RSRP, or the like), Ofn indicates a frequency offset with respect to a frequency of the neighboring cell, Ocn indicates a cell offset with respect to the neighboring cell, Oun indicates a user offset with respect to the neighboring cell, and Hys indicates hysteresis for avoiding frequent occurrence of the event. 
     In addition, in the above-described expression, Ms indicates a measurement result with respect to a secondary cell (for example, RSRQ, RSRP, or the like), Ofs indicates a frequency offset with respect to a frequency of the secondary cell, Ocs indicates a cell offset with respect to the secondary cell, and Oup indicates a user offset with respect to the secondary cell. Off indicates an offset of Event A6. 
     As the user offset Oun with respect to the neighboring cell becomes greater, for example, Event A6 occurs more easily (i.e., the condition for Event A6 is easier to be satisfied). On the other hand, as the user offset Ous with respect to a primary cell becomes greater, Event A6 occurs with greater difficulty (i.e., the condition for Event A6 is more difficult to be satisfied). 
     Note that, although the above-described expression represents the condition for occurrence of Event A6, a condition for end of Event A6 can be expressed as below.
 
 Mn+Ocn+Oun+Hys&lt;Ms+Ocs+Ous+Off   [Math. 27]
 
     (b-7) Event B1 
     Event B1 is an event in which a measurement result with respect to a neighboring cell of a different radio access technology (RAT) exceeds a threshold value. When a user offset is applied to Event B1, for example, a condition for Event B1 is expressed as below.
 
 Mn+Ofn+Oun−Hys &gt;Thresh  [Math. 28]
 
     Meanings of each of the reference symbols included in the above-described expression are as described for Event A3. 
     As the user offset Oun becomes greater, for example, Event B1 occurs more easily (i.e., the condition for Event B1 is easier to be satisfied). On the other hand, as the user offset Oun becomes-smaller, Event B1 occurs with greater difficulty (i.e., the condition for Event B1 is more difficult to be satisfied). 
     Note that, although the above-described expression represents the condition for occurrence of Event B1, a condition for end of Event B1 can be expressed as below.
 
 Mn+Ofn+Oun+Hys &lt;Thresh  [Math. 29]
 
     (b-8) Event B2 
     Event B2 is an event in which a measurement result with respect to a primary cell is smaller than a first threshold value and a measurement result with respect to a neighboring cell of a different RAT exceeds a second threshold value. When a user offset is applied to Event B2, for example, a condition for Event B2 is expressed as below.
 
 Mp+Oup+Hys &lt;Thresh1
 
 Mn+Ofn+Oun−Hys &gt;Thresh2  [Math. 30]
 
     Meanings of each of the reference symbols included in the above-described expression are as described for Event A3 except for Thresh1 and Thresh2. Thresh1 indicates the first threshold value, and Thresh2 indicates the second threshold value. 
     As the user offset Oup with respect to a primary cell becomes greater, for example, Event B2 occurs with greater difficulty (i.e., the condition for Event B2 is more difficult to be satisfied). On the other hand, as the user offset Oun with respect to a neighboring cell becomes greater, Event B2 occurs more easily (i.e., the condition for Event B2 is easier to be satisfied). 
     (c) Application of Offset to New Event 
     The event may be a new event, rather than the above-described existing event. 
     In addition, the new event may be an application-subject event as long as a user has a capability of interference cancellation. 
     For example, a first new event and a second new event may be subject to application under the following conditions. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Relationship of reception power 
                 Application-subject event 
               
               
                   
                   
               
             
            
               
                   
                 Serving cell &gt; Neighboring cell 
                 First new event 
               
               
                   
                 Serving cell &lt; Neighboring cell 
                 Second new event 
               
               
                   
                   
               
            
           
         
       
     
     Note that one of the serving cell and the neighboring cell is, for example, a macrocell, and the other is a small cell. The serving cell is, for example, a primary cell. 
     (c-1) First New Event 
     Condition for First New Event 
     When reception power of a primary cell for a user is greater than reception power of a neighboring cell (or equal to or greater than the reception power), for example, the first new event is applied. A condition for the first new event is, for example, as follows.
 
 Mp 1* Ojp+Ocp+Oup+Hys&lt;Mn 1+ Mn 2+ Ofn+Ocn+Oun   [Math. 31]
 
     In the above-described expression, Mp1 indicates reception power (for example, RSRP) of a primary cell, Ofp indicates a frequency offset with respect to a frequency of the primary cell, Ocp indicates a cell offset with respect to the primary cell, and Oup indicates a user offset with respect to the primary cell. Hys indicates hysteresis for avoiding frequent occurrence of the event. 
     In the above-described expression, Mn1 indicates reception power (for example, RSRP) of a neighboring cell, Mn2 indicates communication quality (for example, RSRQ) of the neighboring cell, Ofn indicates a frequency offset with respect to a frequency of the neighboring cell, Ocn indicates a cell offset with respect to the neighboring cell, and Oun indicates a user offset with respect to the neighboring cell. 
     Although the above-described expression includes a sign of inequality without an equal sign, the expression may include a sign of inequality with an equal sign, instead of the sign of inequality without an equal sign. 
     As the user offset Oun with respect to the neighboring cell becomes greater, for example, the first new event occurs more easily (i.e., the condition therefor is easier to be satisfied). On the other hand, as the user offset Oup with respect to the primary cell becomes greater, the first new event occurs with greater difficulty (i.e., the condition therefor is more difficult to be satisfied). 
     Note that, although the above-described expression represents the condition for occurrence of the first new event, a condition for end of the first new event can be expressed as below.
 
 Mp 1+ Ofp+Ocp+Oup−Hys&gt;Mn 1+ Mn 2+ Ofn+Ocn+Oun   [Math. 32]
 
     Elicitation Process 
     Communication quality Q p  (for example, SINR) of a primary cell is generally expressed as below using reception power P p  of the primary cell, reception power P n  of a neighboring cell, and noise n. 
     
       
         
           
             
               
                 
                   
                     Q 
                     p 
                   
                   = 
                   
                     
                       P 
                       p 
                     
                     
                       
                         P 
                         n 
                       
                       + 
                       n 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     33 
                   
                   ] 
                 
               
             
           
         
       
     
     On the other hand, communication quality Q n  of the neighboring cell is generally expressed as below. 
     
       
         
           
             
               
                 
                   
                     Q 
                     n 
                   
                   = 
                   
                     
                       P 
                       n 
                     
                     
                       
                         P 
                         p 
                       
                       + 
                       n 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     34 
                   
                   ] 
                 
               
             
           
         
       
     
     When the reception power of another signal is greater than the reception power of a target signal, for example, the other signal can be removed as an interfering signal. Thus, when a user has a capability of interference cancellation and the reception power P p  of a signal of a primary cell (an interfering signal) is greater than the reception power P n  of a signal of a neighboring cell (a target signal), the communication quality Q n  of the neighboring cell as a result of interference cancellation can be expressed as below. 
     
       
         
           
             
               
                 
                   
                     Q 
                     n 
                   
                   = 
                   
                     
                       P 
                       n 
                     
                     n 
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     35 
                   
                   ] 
                 
               
             
           
         
       
     
     When the communication quality Q n  of the neighboring cell is better than the communication quality Q p  of the primary cell as shown below, for example, it is desirable to execute a handover (i.e., a change of the primary cell).
 
 Q   p   &lt;Q   n   [Math. 36]
 
     This expression can be developed as below with substitution for the communication quality Q p  and the communication quality Q n . 
     
       
         
           
             
               
                 
                   
                     
                       P 
                       p 
                     
                     
                       
                         P 
                         n 
                       
                       + 
                       n 
                     
                   
                   &lt; 
                   
                     
                       P 
                       n 
                     
                     n 
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     37 
                   
                   ] 
                 
               
             
             
               
                 
                   
                     
                       
                         P 
                         p 
                       
                       n 
                     
                     
                       
                         
                           P 
                           n 
                         
                         n 
                       
                       + 
                       1 
                     
                   
                   &lt; 
                   
                     
                       P 
                       n 
                     
                     n 
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     38 
                   
                   ] 
                 
               
             
             
               
                 
                   
                     
                       
                         P 
                         p 
                       
                       n 
                     
                     
                       
                         P 
                         n 
                       
                       n 
                     
                   
                   &lt; 
                   
                     
                       
                         P 
                         n 
                       
                       n 
                     
                     + 
                     1 
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     39 
                   
                   ] 
                 
               
             
             
               
                 
                   
                     
                       P 
                       p 
                     
                     
                       P 
                       n 
                     
                   
                   &lt; 
                   
                     
                       
                         P 
                         n 
                       
                       n 
                     
                     + 
                     1 
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     40 
                   
                   ] 
                 
               
             
             
               
                 
                   
                     
                       P 
                       p 
                     
                     
                       P 
                       n 
                     
                   
                   &lt; 
                   
                     
                       Q 
                       n 
                     
                     + 
                     1 
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     41 
                   
                   ] 
                 
               
             
           
         
       
     
     Note that, if 1 on the right side is ignored, the above-described expression can be expressed as below.
 
 P   p   &lt;P   n   Q   n   [Math. 42]
 
     Note that, since the reception power P p , the reception power P s , and the communication quality Q n  respectively correspond to Mp1, Mn1, and Mn2 of the condition for the first new event, the above-described condition for the first new event is elicited from the expressions through conversion into a decibel form. 
     (c-1) Second New Event 
     Condition for Second New Event 
     When the reception power of a primary cell for a user is smaller than the reception power of a neighboring cell (or equal to or smaller than the reception power), for example, a second new event is applied. A condition for the second new event is, for example, as below.
 
 Mp 1+ Mp 2+ Ofp+Ocp+Oup+Hys&lt;Mn 1+ Ofn+Ocn+Oun   [Math. 43]
 
     Mp1 indicates the reception power (for example, RSRP) of the primary cell, Mn2 indicates the communication quality (for example, RSRQ) of the primary cell, Ofp indicates a frequency offset with respect to a frequency of the primary cell, Ocp indicates a cell offset with respect to the primary cell, and Oup indicates a user offset with respect to the primary cell. Hys indicates hysteresis for avoiding frequent occurrence of the event. 
     In the above-described expression, Mn1 indicates the reception power (for example, RSRP) of the neighboring cell, Ofn indicates a frequency offset with respect to a frequency of the neighboring cell, Ocn indicates a cell offset with respect to the neighboring cell, and Oun indicates a user offset with respect to the neighboring cell. 
     Although the above-described expression includes a sign of inequality without an equal sign, the expression may include a sign of inequality with an equal sign, instead of the sign of inequality without an equal sigh. 
     As the user offset Oun with respect to the neighboring cell becomes greater, for example, the second new event occurs more easily (i.e., the condition therefor is easier to be satisfied). On the other hand, as the user offset Oup with respect to the primary cell becomes greater, the second new event occurs with greater difficulty (i.e., the condition therefor is more difficult to be satisfied). 
     Note that, although the above-described expression represents the condition for occurrence of the second new event, a condition for end of the second new event can be expressed as below.
 
 Mp 1+ Mp 2+ Ofp+Ocp+Oup&lt;Hys&gt;Mn 1+ Ofn+Ocn+Oun   [Math. 44]
 
     Elicitation Process 
     The communication quality Q p  (for example, SINR) of the primary cell is generally expressed as below using the reception power P p  of the primary cell, the reception power P n  of the neighboring cell, and the noise n. 
     
       
         
           
             
               
                 
                   
                     Q 
                     p 
                   
                   = 
                   
                     
                       P 
                       p 
                     
                     
                       
                         P 
                         n 
                       
                       + 
                       n 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     45 
                   
                   ] 
                 
               
             
           
         
       
     
     When the reception power of another signal is greater than the reception power of a target signal, for example, the other signal can be removed as an interfering signal. Thus, when a user has a capability of interference cancellation and the reception power P n  of a signal of the neighboring cell (an interfering signal) is greater than the reception power P p  of a signal of the primary cell (a target signal), the communication quality Q p  of the primary cell as a result of interference cancellation can be expressed as below. 
     
       
         
           
             
               
                 
                   
                     Q 
                     p 
                   
                   = 
                   
                     
                       P 
                       p 
                     
                     n 
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     46 
                   
                   ] 
                 
               
             
           
         
       
     
     On the other hand, the communication quality Q n  of the neighboring cell is generally expressed as below. 
     
       
         
           
             
               
                 
                   
                     Q 
                     n 
                   
                   = 
                   
                     
                       P 
                       n 
                     
                     
                       
                         P 
                         p 
                       
                       + 
                       n 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     47 
                   
                   ] 
                 
               
             
           
         
       
     
     When the communication quality Q n  of the neighboring cell is better than the communication quality Q p  of the primary cell as shown below, for example, it is desirable to execute a handover (i.e., a change of the primary cell).
 
 Q   p   &lt;Q   n   [Math. 48]
 
     This expression can be developed as below with substitution for the communication quality Q p  and the communication quality Q n . 
     
       
         
           
             
               
                 
                   
                     
                       P 
                       p 
                     
                     n 
                   
                   &lt; 
                   
                     
                       P 
                       n 
                     
                     
                       
                         P 
                         p 
                       
                       + 
                       n 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     49 
                   
                   ] 
                 
               
             
             
               
                 
                   
                     
                       P 
                       p 
                     
                     n 
                   
                   &lt; 
                   
                     
                       
                         P 
                         n 
                       
                       n 
                     
                     
                       
                         
                           P 
                           p 
                         
                         n 
                       
                       + 
                       1 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     50 
                   
                   ] 
                 
               
             
             
               
                 
                   
                     
                       
                         P 
                         p 
                       
                       n 
                     
                     + 
                     1 
                   
                   &lt; 
                   
                     
                       
                         P 
                         n 
                       
                       n 
                     
                     
                       
                         P 
                         p 
                       
                       n 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     51 
                   
                   ] 
                 
               
             
             
               
                 
                   
                     
                       
                         P 
                         p 
                       
                       n 
                     
                     + 
                     1 
                   
                   &lt; 
                   
                     
                       P 
                       n 
                     
                     
                       P 
                       p 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     52 
                   
                   ] 
                 
               
             
             
               
                 
                   
                     
                       Q 
                       p 
                     
                     + 
                     1 
                   
                   &lt; 
                   
                     
                       P 
                       n 
                     
                     
                       P 
                       p 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     53 
                   
                   ] 
                 
               
             
           
         
       
     
     Note that, if 1 on the left side is ignored, the above-described expression can be expressed as below.
 
 P   p   Q   p   &lt;P   n   [Math. 54]
 
     Note that, since the reception power P p , the communication quality Q p , and the reception power P n  respectively correspond to Mp1, Mp1, and Mn1 of the condition for the second new event, the above-described condition for the second new event is elicited from the expressions through conversion into a decibel form. 
     (d) State Transition of Event 
     A state of a user related to an event (which will be referred to as an “event state” below) is, for example, managed within the user. An example of the event state will be described below with reference to  FIG. 9 . 
       FIG. 9  is an explanatory diagram for describing an example of the event state. Referring to  FIG. 9 , an event state is one of “in-event” or “out-of-event” The event state transitions from “out-of-event” to “in-event” in accordance with, for example, occurrence of an event. In other words, a user gets in (enters) “in-event.” On the other hand, the event state transitions from “in-event” to “out-of-event” in accordance with an end of an event. In other words, a user gets out of (leaves) “in-event.” 
     (e) Examples of User Offset 
     (e-1) Value Corresponding to Capability of Interference Cancellation 
     The user offset is, for example, a value corresponding to a capability of interference cancellation of the user (i.e., the terminal device  200 ). 
     Specifically, the user offset is greater when the user has a capability of interference cancellation, for example, and is smaller when the user has no capability of interference cancellation. As an example, the user offset is a positive value when the user has a capability of interference cancellation, and 0 (or a value smaller than a positive value) when the user has no capability of interference cancellation. As another example, the user offset may take one among three values, rather than taking one of two values. In this case, the user offset may be a greater value when the user can execute interference cancellation with higher performance, or may be a smaller value when the user can execute interference cancellation with lower performance. 
     Accordingly, even if a measurement result with respect to a cell were a little poor, for example, a user having a capability of interference cancellation (i.e., a user that can reduce interference from a neighboring cell) could use the cell. That is, a user that can execute interference cancellation can use the cell even under severe conditions. 
     (e-2) Value Corresponding to Cell/Type of Cell 
     The user offset is, for example, a value corresponding to the cell or a type of the cell. 
     Specifically, for example, the user offset is greater when the cell is a small cell, and smaller when the cell is a macrocell. In other words, the user offset is greater in a case corresponding to a small cell, and smaller in a case corresponding to a macrocell. 
     Accordingly, for example, it is possible to cause a user having a capability of interference cancellation (i.e., a user that can reduce interference from a neighboring cell) to use the small cell, rather than the macrocell by priority. In other words, the user that can execute interference cancellation can use the small cell even under severe conditions. Thus, offloading onto the small cell can be promoted. 
     (e-3) Value Corresponding to Event State 
     The user offset may have different values for occurrence and end of an event. In other words, the user offset may have a value corresponding to an event state. 
     The user offset may have, for example, a first value for a condition for occurrence of an event, and a second value that is different from the first value for a condition for end of the event. In other words, the user offset has the first value when an event state is “out-of-event,” and the second value when an event state is “in-event.” 
     (e-4) Cell Range Extension (CRE) 
     CRE of each user is possible due to, for example, measurement reporting in accordance with a user offset. CRE is a technique of enabling selection of a specific cell to be easy (or enabling selection of a specific cell to be difficult) using an offset. CRE can also be said to be a technique of adjusting an extent of a specific cell using an offset. As an example, a small cell is easier to select for a user having a capability of interference cancellation. In other words, an extent of a small cell is adjusted to be greater. 
     (f) Process Flow 
     An example of a process for measurement reporting in accordance with a user offset will be described with reference to  FIGS. 10 and 11 . 
     (f-1) Overall Process 
       FIG. 10  is a sequence diagram showing an example of a schematic flow of an overall process for measurement reporting in accordance with a user offset. 
     The terminal device  200  notifies the base station  100  of a capability of Interference cancellation of the user (i.e., the terminal device  200 ) (S 401 ). 
     The base station  100  decides on an offset (i.e., a user offset) for the user (i.e., the terminal device  200 ) relating to interference cancellation on the basis of the capability (S 403 ). Then, the base station  100  notifies the terminal device  200  of the user offset (S 405 ). 
     The terminal device  200  performs measurement with respect to a cell (S 407 ). Then, the terminal device  200  determines a condition for an event that triggers measurement reporting with respect to the cell in accordance with the user offset (S 409 ). 
     When the event has occurred (i.e., when the condition therefor is satisfied), the terminal device  200  performs measurement reporting to the base station  100  (S 411 ). In other words, the terminal device  200  reports a measurement result to the base station  100 . 
     Note that the base station  100  may select a cell for the terminal device  200  on the basis of the measurement result. The cell may be a target cell for a handover of the terminal device  200 . In other words, the base station  100  may make a decision on a handover for the terminal device  200  on the basis of the measurement result. Alternatively, the cell may be a secondary cell for the terminal device  200 . The base station  100  may decide addition or deletion of a secondary cell (a secondary component carrier) for the terminal device  200  on the basis of the measurement result. 
     (f-2) Process of Terminal Device 
       FIG. 11  is a sequence diagram showing an example of a schematic flow of a process of the terminal device  200  for measurement reporting in accordance with a user offset. The process corresponds to Steps S 407  to S 411  described with reference to  FIG. 10 . 
     The terminal device  200  performs measurement with respect to the cell (S 421 ). The terminal device  200  may perform filtering on a measurement result when necessary. 
     When a timing at which a condition for an event that triggers measurement reporting is to be determined arrives (Yes in S 423 ), succeeding processes are executed. When it does not (No in S 423 ), the process ends. 
     The terminal device  200  determines a condition for an event that triggers measurement reporting in accordance with a user offset (S 425 ). The condition includes the user offset. The event is, for example, one of Event A1 to A6, B1, and B2. Note that, when the terminal device  200  has a capability of interference cancellation, the event may be the above-described first new event or second new event. 
     When the condition for the event is satisfied (Yes in S 427 ), the terminal device  200  performs measurement reporting with respect to the cell (S 429 ). When it is not (No in S 427 ), the process ends. 
     As described above, for example, measurement reporting is performed in accordance with the user parameter. Accordingly, measurement reporting can be performed in consideration of, for example, interference cancellation. More specifically, for example, a frequency of measurement reporting is adjusted in accordance with whether interference cancellation is performed. 
     (g) Modified Example 
     In the above-described example, the terminal device  200  performs measurement reporting with respect to a cell in accordance with a user offset. However, an embodiment of the present disclosure is not limited thereto. As a modified example, the base station  100  may select a cell for a user in accordance with a user offset. 
     (g-1) Handover 
     The selection may be, for example, selection of a target cell for handover of the user (i.e., the terminal device  200 ). In other words, the base station  100  may make a decision on a handover for the user (i.e., the terminal device  200 ) in accordance with a user offset. 
     The information acquisition unit  151  may acquire the user offset, and the control unit  153  may make a decision on a handover for the user in accordance with the user offset. 
     More specifically, the base station  100  (the control unit  153 ) may determine a condition for a handover in accordance with the user offset. As an example, the base station  100  (the control unit  153 ) may add the user offset to the measurement result, and determine the condition on the basis of the value obtained after the addition. Then, when the condition is satisfied, the base station  100  (the control unit  153 ) may decide a handover of the user (the terminal device  200 ) to the target cell. In other words, the base station  100  (the control unit  153 ) may select the target cell. 
     Overall Process 
       FIG. 12  is a sequence diagram showing an example of a schematic flow of an overall process for a decision on a handover in accordance with a user offset. 
     The terminal device  200  notifies the base station  100  of a capability of interference cancellation of the user (i.e., the terminal device  200 ) (S 441 ). 
     The base station  100  decides on an offset (i.e., a user offset) for the user (i.e., the terminal device  200 ) relating to interference cancellation on the basis of the capability (S 443 ). 
     The terminal device  200  performs measurement with respect to a cell (S 445 ). Then, the terminal device  200  determines a condition for an event that triggers measurement reporting with respect to the cell (S 447 ). 
     When the event has occurred (i.e., when the condition therefor is satisfied), the terminal device  200  performs measurement reporting to the base station  100  (S 449 ). In other words, the terminal device  200  reports a measurement result to the base station  100 . 
     The base station  100  (the control unit  153 ) determines a condition for a handover in accordance with the user offset (S 451 ). As an example, the base station  100  (the control unit  153 ) adds the user offset to the measurement result, and determines the condition on the basis of the value obtained after the addition. 
     When the condition is satisfied, the base station  100  (the control unit  153 ) decides a handover of the user (i.e., the terminal device  200 ) to a target cell (S 453 ). In other words, the base station  100  (the control unit  153 ) selects the target cell. Thereafter, the base station  100  (the control unit  153 ) performs a handover procedure (S 455 ). 
     Process of Base Station  100   
       FIG. 13  is a sequence diagram showing an example of a schematic flow of a process of the base station  100  for a decision on a handover in accordance with a user offset. The process corresponds to Steps S 451  and S 453  described with reference to  FIG. 12 . 
     The base station  100  acquires the measurement result with respect to the cell reported by the user (i.e., the terminal device  200 ) (S 461 ). The base station  100  may perform, filtering on the measurement result when necessary. 
     When a timing at which a condition for a handover of the user is to be determined arrives (Yes in S 463 ), succeeding processes are executed. When it does not (No in S 463 ), the process ends. 
     The base station  100  determines a condition for a handover of the user in accordance with the user offset (S 465 ). The condition includes the user offset. 
     When the condition for the handover is satisfied (Yes in S 467 ), the base station  100  decides a handover of the user (i.e., the terminal device  200 ) to the target cell (S 469 ). When it is not (No in S 467 ), the process ends. 
     (g-2) Addition/Deletion of Secondary Cell 
     The selection may be, for example, selection of a secondary cell for the user (i.e., the terminal device  200 ). In other words, the base station  100  may decide addition or deletion of a secondary cell for the user (i.e., the terminal device  200 ) in accordance with a user offset. 
     The information acquisition unit  151  acquires, for example, a user offset. In addition, the control unit  153  may decide addition or deletion of a secondary cell for the user in accordance with the user offset. 
     More specifically, the base station  100  (the control unit  153 ) may determine a condition for addition or deletion of a secondary cell in accordance with the user offset. As an example, the base station  100  (the control unit  153 ) may add the user offset to the measurement result and determine the condition on the basis of the value obtained after the addition. Then, when the condition is satisfied, the base station  100  (the control unit  153 ) may decide addition or deletion of a secondary cell for the user. In other words, the base station  100  (the control unit  153 ) may select the secondary cell. 
     Note that the flow of a “process for a decision on addition or deletion of a secondary cell in accordance with a user offset” is similar to the flow of the above-described “process for a decision on a handover in accordance with a user offset” except for the difference in targets that are “handover” and “addition or deletion of a secondary cell.” 
     A cell is selected in accordance with, for example, a user parameter as described above. Accordingly, it is possible to perform a handover or addition/deletion of a secondary cell in consideration of, for example, interference cancellation. 
     (4) Second Example (Measurement Reporting in Accordance with Timer Value for User 
     For the second example, the user parameter is a timer value for the user (i.e., the terminal device  200 ) relating to interference cancellation, and the timer value is set for a timer to be used for measurement reporting as described above. The terminal device  200  (the control unit  243 ) performs measurement reporting with respect to a cell in accordance with the timer value. 
     (a) Timer 
     The timer starts when, for example, a condition for an event that triggers measurement reporting is satisfied. Furthermore, the timer is reset when, for example, the condition is not satisfied. 
     The terminal device  200  (the control unit  243 ) performs measurement reporting with respect to the cell, for example, after the timer expires. 
     (b) Example of Timer Value 
     (b-1) Value Corresponding to Capability of Interference Cancellation 
     The timer value is, for example, a value, corresponding to a capability of interference cancellation of the user (i.e., the terminal device  200 ). 
     Specifically, the timer value is, for example, greater when the user has a capability of interference cancellation, and smaller when the user has no capability of interference cancellation. In other words, a timer value T IC  when the user has a capability of interference cancellation and a timer value T noIC  when the user has no capability of interference cancellation have the following relationship.
 
0≤ T   noIC   &lt;T   IC   [Math. 55]
 
     Accordingly, a frequency of handovers of the terminal device having the capability of interference cancellation can decrease. More specifically, the terminal device having the capability of interference cancellation performs measurement reporting under a condition that, for example, the condition for the event is continuously satisfied over a long period of time. Thus, when the event occurs but the event ends in a short period of time, the terminal device does not perform measurement reporting. Thus, a frequency of measurement reporting decreases, and as a result, a frequency of handovers can decrease accordingly. Since the terminal device having the capability of interference cancellation can maintain communication quality even in a slightly poor environment, the above-described technique can be used. 
       FIG. 14  is an explanatory diagram for describing an example of a relationship between a capability of interference cancellation and communication quality. Referring to  FIG. 14 , a relationship between a distance from a base station (for example, a base station of a small cell) and communication quality is shown. The communication quality of communication between a terminal device and a base station becomes lower as the terminal device becomes more distant from the base station. When the terminal device has a capability of interference cancellation, for example, the terminal device can remove interference from another cell (for example, a macrocell). Therefore, the communication quality more gently decreases in accordance with an increase in the distance from the base station when the terminal device has the capability of interference cancellation than when the terminal device has no capability of interference cancellation. 
     (b-2) Value Corresponding to Cell/Type of Cell 
     The timer value is, for example, a value corresponding to the cell/the type of cell. 
     Specifically, the timer value is, for example, greater when the serving cell of the user (i.e., the terminal device  200 ) is a small cell, and smaller when the serving cell is a macrocell. In other words, timer values T IC,Small  and T noIC,Small  when the serving cell of the user is a small cell and timer values T IC,Macro  and T noIC,Macro  when the serving cell of the user is a macrocell have the following relationships.
 
0≤ T   noIC,Macro   &lt;T   noIC,Small  
 
0≤ T   IC,Macro   &lt;T   IC,Small   [Math. 56]
 
     Accordingly, it is possible to cause, for example, the user having the capability of interference cancellation (i.e., a user that can make interference from a neighboring cell small) to use the small cell, rather than the macrocell by priority. In other words, the user that can execute interference cancellation can use the small cell even under severe conditions. Thus, offloading onto the small cell can be promoted. 
     (b-3) Decision on Value Using Scaling Factor 
     The timer value may be adjusted with a scaling factor. As an example, the following scaling factors may be provided. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Scaling Factor 
                 Value 
               
               
                   
                   
               
             
            
               
                   
                 Scaling Factor for User with Interference Cancellation 
                 α IC   
               
               
                   
                 Scaling Factor for User with no Interference Cancellation 
                 α noIC   
               
               
                   
                 Scaling Factor for Serving Cell 
                 β Cell   
               
               
                   
                   
               
            
           
         
       
     
     A timer value T IC  when the user has a capability of interference cancellation and a timer value T noIC  when the user has no capability of interference cancellation may be computed using the above-described scaling factors, and a baseline timer value T Base  as below.
 
 T   IC,Cello =α IC β Cell   T   Base &gt;0
 
 T   noIC,Cell =α noIC β Cell   T   Base ≥0  [Math. 57]
 
     Note that the scaling factors have, for example, the following relationships.
 
0≤α noIC &lt;α IC  
 
0≤β Macro &lt;β Small   [Math. 58]
 
     Note that the base station  100  may transmit the baseline timer value T Base  kid the scaling factors, instead of transmitting timer values. In addition, the terminal device  200  may compute a timer value from the baseline timer value T Base  and the scaling factors, and perform measurement reporting in accordance with the timer value. 
     (c) Process Flow 
     Examples of processes relating to measurement reporting, in accordance with a timer value will be described with reference to  FIGS. 15 to 17 . 
     (f-1) Overall Process 
       FIG. 15  is a sequence diagram showing an example of a schematic flow of an overall process for measurement reporting in accordance with a timer value. 
     The terminal device  200  notifies the base station  100  of a capability of interference cancellation of the user (i.e., the terminal device  200 ) (S 481 ). 
     The base station  100  decides on a timer value for the user (i.e., the terminal device  200 ) relating to interference cancellation on the basis of the capability (S 483 ). Then, the base station  100  notifies the terminal device  200  of the timer value (S 485 ). 
     The terminal device  200  performs measurement with respect to a cell (S 487 ). Then, the terminal device  200  determines a condition for an event that triggers measurement reporting with respect to the cell (S 489 ). 
     When the event has occurred (i.e., when the condition therefor is satisfied), the terminal device  200  performs measurement reporting to the base station  100  in accordance with the timer value (S 491 ). In other words, the terminal device  200  reports a measurement result to the base station  100  in accordance with the timer value. 
     Note that the base station  100  may select a cell for the terminal device  200  on the basis of the measurement result. The cell may be a target cell for a handover of the terminal device  200 . In other words, the base station  100  may make a decision on a handover of the terminal device  200  on the basis of the measurement result. Alternatively, the cell may be a secondary cell for the terminal device  200 . The base station  100  may decide addition or deletion of a secondary cell (a secondary component carrier) for the terminal device  200  on the basis of the measurement result. 
     (f-2) Process of Terminal Device 
     First Example 
       FIG. 16  is a sequence diagram showing a first example of a schematic flow of a process of the terminal device  200  for measurement reporting in accordance with a user offset. The process corresponds to Steps S 489  and S 491  described with reference to  FIG. 15 . 
     The terminal device  200  determines a condition for an event that triggers measurement reporting with respect to a cell (S 501 ). 
     When an event state has changed (Yes in S 503 ), the terminal device  200  (the control unit  243 ) restarts a timer (S 511 ), and stands by until the next determination timing (S 513 ). Thereafter, the process returns to Step S 501 . The change of the event state may be a change from “out-of-event” to “in-event,” or a change from “in-event” to “out-of-event.” Note that “restart a timer” means resetting of a timer and then starting of the timer. 
     When an event state has not changed (No in S 503 ), the terminal device  200  (the control unit  243 ) checks whether a timer has already started (S 505 ). 
     When the timer has not yet started (No in S 505 ), the timer is regarded as having an error, and thus the terminal device  200  (the control unit  243 ) restarts the timer (S 511 ), and stands by until the next determination timing (S 513 ). Thereafter, the process returns to Step S 501 . 
     When the timer has already started (Yes in S 505 ), the terminal device  200  (the control unit  243 ) checks whether the timer has expired (S 507 ). 
     When the timer has not yet expired (No in S 507 ), the terminal device  200  (the control unit  243 ) stands by until the next determination timing (S 513 ). Thereafter, the process returns to Step S 501 . 
     When the timer has expired (Yes in S 507 ), the terminal device  200  (the control unit  243 ) performs measurement reporting to the base station  100  (S 509 ). Thereafter, the terminal device  200  (the control unit  243 ) restarts the timer (S 511 ), and stands by until the next determination timing (S 513 ). Thereafter, the process returns to Step S 501 . 
     Second Example 
       FIG. 17  is a sequence diagram showing a second example of a schematic flow of a process of the terminal device  200  for measurement reporting in accordance with a user offset. The process corresponds to Steps S 489  and S 491  described with reference to  FIG. 15 . In particular, measurement reporting is performed in the second example when an event state changes from “out-of-event” to “in-event.” 
     The terminal device  200  determines a condition for an event that triggers measurement reporting with respect to a cell (S 521 ). 
     When an event state before the determination is “out-of-event” (Yes in S 523 ), and then the event state changes from “out-of-event” to “in-event” (Yes in S 525 ), the terminal device  200  (the control unit  243 ) starts a timer (S 527 ), and stands by until the next determination timing (S 529 ). Thereafter, the process returns to Step S 521 . 
     When the event stale remains “out-of-event” (No in S 525 ), the terminal device  200  (the control unit  243 ) stands by until the next determination timing (S 529 ). Thereafter, the process returns to Step S 521 . 
     When the event state before the determination is “in-event” (No in S 523 ), and then the event state changes from “in-event” to “out-of-event” (Yes in S 531 ), the terminal device  200  (the control unit  243 ) resets the timer (S 539 ), and stands by until the next determination timing (S 529 ). Thereafter, the process returns to Step S 521 . 
     When the event state remains “in-event” (No in S 531 ), the terminal device  200  (the control unit  243 ) checks whether the timer has already started (S 533 ). 
     When the timer has not yet started (No in S 533 ), the timer is regarded as having an error, and thus the terminal device  200  (the control unit  243 ) restarts the timer (S 541 ), and stands by until the next determination timing (S 529 ). Thereafter, the process returns to Step S 521 . 
     When the timer has already started (Yes in S 533 ), the terminal device  200  (the control unit  243 ) checks whether the timer has expired (S 535 ). 
     When the timer has not yet expired (No in S 535 ), the terminal device  200  (the control unit  243 ) stands by until the next determination timing (S 529 ). Thereafter, the process returns to Step S 521 . 
     When the timer has expired (Yes in S 535 ), the terminal device  200  (the control unit  243 ) performs measurement reporting to the base station  100  (S 537 ). Thereafter, the terminal device  200  (the control unit  243 ) resets the timer (S 539 ), and stands by until the next determination timing (S 529 ). Thereafter, the process returns to Step S 521 . 
     As described above, a cell is selected in accordance with, for example, a timer value for a user. Accordingly, it is possible to perform measurement reporting in consideration of, for example, interference cancellation. More specifically, a frequency of measurement reporting is adjusted in accordance with, for example, whether interference cancellation is performed. 
     (5) Third Example (Measurement in Accordance with Correction Value for User 
     As the third example, the user parameter is a correction value for the user (i.e., the terminal device  200 ) relating to interference cancellation, and the correction value is to be used in measurement of communication quality as described above. The terminal device  200  (the control unit  243 ) performs measurement of the communication quality of the cell in accordance with the correction value. 
     (a) Communication Quality 
     The communication quality is, for example, an SNR. Alternatively, the communication quality may be an SINR or RSRQ. 
     (b) Correction Value 
     The correction value is, for example, a correction value for subtracting interference components from the communication quality in accordance with a capability of interference cancellation of the user. 
     The correction value is, for example, a value corresponding to a capability of interference cancellation of the user (i.e., the terminal device  200 ). Specifically, the correction value is, for example, greater when the user has a capability of interference cancellation, and smaller when the user has no capability of interference cancellation. 
     (b-1) First Example 
     As a first example, the communication quality (for example, an SNR) of a cell can be computed using a correction value as below. 
     
       
         
           
             
               
                 
                   
                     SNR 
                     Cell 
                   
                   = 
                   
                     E 
                     ⁢ 
                     
                       { 
                       
                         
                           RSRP 
                           Cell 
                         
                         
                           ( 
                           
                             
                               RSSI 
                               ⁢ 
                               
                                 / 
                               
                               ⁢ 
                               N 
                             
                             - 
                             
                               C 
                               1 
                             
                           
                           ) 
                         
                       
                       } 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     59 
                   
                   ] 
                 
               
             
           
         
       
     
     In the above-described expression, the correction value C 1  is subtracted from RSSI/N that corresponds to interference and noise. When the terminal device  200  (i.e., a user) has a capability of interference cancellation, for example, the correction value C 1  is a positive value, and when the terminal device  200  has no capability of interference cancellation, the correction value C 1  is 0. In other words, when the terminal device  200  has a capability of interference cancellation, better communication quality obtained as a result of interference cancellation is computed. 
     Note that, although the example in which the left side of the above-described expression is an SNR has been described, the left side of the above-described expression may be an SINR or RSRQ, instead of an SNR. 
     (b-2) Second Example 
     As a second example, the communication quality (for example, an SNR) with respect to a cell can be computed using a correction value as below. 
     
       
         
           
             
               
                 
                   
                     SNR 
                     Cell 
                   
                   = 
                   
                     
                       E 
                       ⁢ 
                       
                         { 
                         
                           
                             RSRP 
                             Cell 
                           
                           
                             RSSI 
                             ⁢ 
                             
                               / 
                             
                             ⁢ 
                             N 
                           
                         
                         } 
                       
                     
                     + 
                     
                       C 
                       2 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     60 
                   
                   ] 
                 
               
             
           
         
       
     
     In the above-described expression, the correction value C 2  is added to a value that corresponds to general RSRQ (the first term on the right side). When, for example, the terminal device  200  (i.e., a user) has a capability of interference cancellation, the correction value C 2  is a positive value, and when the terminal device  200  has no capability of interference cancellation, the correction value C 2  is 0. In other words, when the terminal device  200  has a capability of interference cancellation, better communication quality obtained as a result of interference cancellation is computed. The correction value C 2  corresponds to an increment of a gain from interference cancellation. The above-described expression has an advantage that general RSRQ can be used. 
     Note that although the example in which the left side of the above-described expression is an SNR has been described, the left side of the above-described expression may be an SINR or RSRQ, instead of an SNR. 
     (b-3) Third Example 
     As a third example, the communication quality (for example, an SNR) of a cell can be computed using a correction value as below. 
     
       
         
           
             
               
                 
                   
                     SNR 
                     Cell 
                   
                   = 
                   
                     E 
                     ⁢ 
                     
                       { 
                       
                         
                           RSRP 
                           Cell 
                         
                         
                           [ 
                           
                             
                               ( 
                               
                                 RSSI 
                                 ⁢ 
                                 
                                   / 
                                 
                                 ⁢ 
                                 N 
                               
                               ) 
                             
                             - 
                             
                               C 
                               3 
                             
                           
                           ] 
                         
                       
                       } 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     61 
                   
                   ] 
                 
               
             
           
         
       
     
     In the above-described expression, the correction value C 3  is subtracted from RSSI/N that corresponds to interference and noise. In this example, in particular, the correction value C 3  is computed as below. 
     
       
         
           
             
               
                 
                   
                     C 
                     3 
                   
                   = 
                   
                     
                       N 
                       
                         RS 
                         , 
                         Cell 
                       
                     
                     ⁢ 
                     
                       
                         ∑ 
                         
                           
                             c 
                             ′ 
                           
                           ∈ 
                           
                             C 
                             Cell 
                           
                         
                       
                       ⁢ 
                       
                         RSRP 
                         
                           c 
                           ′ 
                         
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                     ⁢ 
                     62 
                   
                   ] 
                 
               
             
           
         
       
     
     In the above-described expression, N RS,Cell  is the number of resource elements on which a reference signal is transmitted within a channel bandwidth of a cell to be measured, and C cell  is a set of other cells that are subject to interference cancellation (which will be referred to as “removal target cells” below) during measurement of the cell. That is, the correction value C 3  is a value of interference that is expected to be actually removed. Thus, in the above-described expression for computing SNR cell , the value of interference that is expected to be actually removed (i.e., the correction value C 3 ) is subtracted from RSSI/N that corresponds to interference and noise. 
     The set C cell  depends on, for example, a capability of interference cancellation of the terminal device  200  (i.e., a user). Specifically, the maximum number of cells to be removed is decided on, for example, in accordance with the capability of interference cancellation of the terminal device  200 , and the set C cell  includes cells of which the number is equal to or smaller than the maximum number. Thus, as the terminal device  200  can remove interference from even more cells, better communication quality can be computed. Note that, when there are a greater number of cells than the maximum number, it is desirable that cells that bring greater reception power be included in the set C cell . This is because signals having greater reception power can be more easily removed. 
     Note that, although the example in which the left side of the above-described expression is an SNR has been described, the left side of the above-described expression may be an SINR or RSRQ, instead of an SNR. 
     In the third example, the correction value (i.e., a correction value for subtracting interference components from the communication quality in accordance with the capability of interference cancellation of the user) is, for example, a value computed from a measurement result with respect to one or more other cells selected in accordance with the capability of interference cancellation of the user as described above. The one or more other cells are, for example, a number of other cells corresponding to the capability. Thus, more substantive communication quality, for example, can be measured. 
     (c) Process Flow 
     Examples of processes for measurement in accordance with a correction value will be described with reference to  FIGS. 18 to 20 . 
     (c-1) First Example 
       FIG. 18  is a sequence diagram showing a first example of a schematic flow of a process for measurement in accordance with a correction value. This example is of a process when, for example, the above-described first example (C 1 ) or second example (C 2 ) of the correction value is used. 
     The terminal device  200  notifies the base station  100  of a capability of interference cancellation of the user (i.e., the terminal device  200 ) (S 561 ). 
     The base station  100  decides on a correction value for the user (i.e., the terminal device  200 ) relating to interference cancellation on the basis of the capability (S 563 ). Then, the base station  100  notifies the terminal device  200  of the correction value (S 565 ). 
     The terminal device  200  performs measurement with respect to a cell in accordance with the correction value (S 567 ). Then, the terminal device  200  determines a condition for an event that triggers measurement reporting with respect to the cell (S 569 ). 
     When the event has occurred (i.e., when the condition therefor is satisfied), the terminal device  200  performs measurement reporting to the base station  100  (S 571 ). In other words, the terminal device  200  reports a measurement result to the base station  100 . 
     Note that the base station  100  may select a cell for the terminal device  200  on the basis of the measurement result. The cell may be a target cell for a handover of the terminal device  200 . In other words, the base station  100  may make a decision on a handover for the terminal device  200  on the basis of the measurement result. Alternatively, the cell may be a secondary cell for the terminal device  200 . The base station  100  may decide addition or deletion of a secondary cell (a secondary component carrier) for the terminal device  200  on the basis of the measurement result. 
     (c-2) Second Example 
       FIG. 19  is a sequence diagram showing a second example of a schematic flow of a process for measurement in accordance with a correction value. This example is of a process when, for example, the above-described third example (C 3 ) of the correction value is used, in which the terminal device  200  decides on a set of removal target cells. 
     The terminal device  200  decides on a set of removal target cells on the basis of a capability of interference cancellation of a user (i.e., the terminal device  200 ) and a measurement result (S 581 ). Further, the terminal device  200  decides on a correction value for the user (i.e., the terminal device  200 ) relating to interference cancellation on the basis of the set (S 583 ). 
     The terminal device  200  performs measurement with respect to the cells in accordance with the correction value (S 585 ). Then, the terminal device  200  determines a condition for an event that triggers measurement reporting with respect to the cell (S 587 ). 
     When the event has occurred (i.e., when the condition therefor is satisfied), the terminal device  200  performs measurement reporting to the base station  100  (S 589 ). In other words, the terminal device  200  reports a measurement result to the base station  100 . 
     Note that the base station  100  may select a cell for the terminal device  200  on the basis of the measurement result. The cell may be a target cell for a handover of the terminal device  200 . In other words, the base station  100  may make a decision on a handover for the terminal device  200  on the basis of the measurement result. Alternatively, the cell may be a secondary cell for the terminal device  200 . The base station  100  may decide addition or deletion of a secondary cell (a secondary component carrier) for the terminal device  200  on the basis of the measurement result. 
     (c-3) Third Example 
       FIG. 20  is a sequence diagram showing a third example of a schematic flow of a process for measurement in accordance with a correction value. This example is of a process when, for example, the above-described third example (C 3 ) of the correction value is used, in which the base station  100  decides on a set of removal target cells. 
     The terminal device  200  notifies the base station  100  of a capability of interference cancellation of the user (i.e., the terminal device  200 ) (S 601 ). 
     The terminal device  200  performs measurement with respect to cells (S 603 ). Then, the terminal device  200  determines a condition for an event that triggers measurement reporting with respect to the cell (S 605 ). 
     When the event has occurred (i.e., when the condition therefor is satisfied), the terminal device  200  performs measurement reporting to the base station  100  (S 607 ). In other words, the terminal device  200  reports a measurement result to the base station  100 . 
     The base station  100  decides on a set of removal target cells on the basis of the capability and the measurement result (S 609 ). Then, the base station  100  notifies the terminal device  200  of the set (S 611 ). The base station  100  may also notify a base station in a neighboring cell of the set, or may share the set with cells. 
     The terminal device  200  decides on a correction value for the user (i.e., the terminal device  200 ) relating to interference cancellation on the basis of the set (S 613 ). 
     The terminal device  200  performs measurement with respect to the cells in accordance with the correction value (S 615 ). Then, the terminal device  200  determines a condition for an event that triggers measurement reporting with respect to the cells (S 617 ). 
     When the event has occurred (i.e., when the condition therefor is satisfied), the terminal device  200  performs measurement reporting to the base station  100  (S 619 ). In other words, the terminal device  200  reports a measurement result to the base station  100 . 
     Note that the base station  100  may select a cell for the terminal device  200  on the basis of the measurement result. The cell may be a target cell for a handover of the terminal device  200 . In other words, the base station  100  may make a decision on a handover for the terminal device  200  on the basis of the measurement result. Alternatively, the cell may be a secondary cell for the terminal device  200 . The base station  100  may decide addition or deletion of a secondary cell (a secondary component carrier) for the terminal device  200  on the basis of the measurement result. 
     The base station  100  may decide on, for example, a set of removal target cells as described above. Note that, instead of the base station  100 , another node (for example, a core network node, or the like) may decide on a set of removal target cells. 
     (c-4) Decision on Set of Removal Target Cells 
       FIG. 21  is a sequence diagram showing an example of a schematic flow of a process for deciding a set of cancellation target cells. The process is executed by the terminal device  200 , and corresponds to Step S 581  described with reference to  FIG. 19 . 
     The terminal device  200  acquires the RSRP of each cell (S 621 ). Then, the terminal device  200  selects M+1 cells that bring greater RSRP (S 623 ). M is the maximum number of removal target cells in accordance with a capability of interference cancellation of the terminal device  200 . 
     When a measurement target cell is included in the M+1 selected cells (Yes in S 625 ), the terminal device  200  decides on the cells other than the measurement target cell among M+1 selected cells as a set of removal target cells (S 627 ). Then, the process ends. 
     When no measurement target cell is included in the M1 selected cells (No in S 625 ), the terminal device  200  decides on cells other than the cell that brings minimum RSRP among the M+1 selected cells as a set of removal target cells (S 629 ). Then, the process ends. 
     Note that the process may be executed by the base station  100 , instead of the terminal device  200 . In this case, the process may correspond to the Step S 609  described with reference to  FIG. 20 . 
     (d) Modified Example 
     In the above-described examples, the terminal device  200  performs measurement with respect to a cell in accordance with a correction value. However, an embodiment of the present disclosure is not limited thereto. As a modified example, the base station  100  may perform measurement with respect to a cell in accordance with a correction value. 
     The information acquisition unit  151  acquires, for example, a correction value for the user (i.e., the terminal device  200 ) relating to interference cancellation, and the correction value is to be used in measurement of communication quality. In addition, the control unit  153  performs measurement of the communication quality of the cell in accordance with the correction value. 
     More specifically, the terminal device  200  notifies the base station  100  of, for example, a capability of interference cancellation of a user (i.e., the terminal device  200 ), and the base station  100  (the processing unit  150 ) decides on a correction value of the user relating to interference cancellation on the basis of the capability. Then, the base station  100  (the information acquisition unit  151 ) acquires the correction value, and the base station  100  (the control unit  153 ) computes a new measurement result from the correction value and a measurement result reported by the terminal device  200 . The base station  100 , for example, performs measurement of communication quality in this manner. 
     (d-1) Process Flow (Fourth Example) 
       FIG. 22  is a sequence diagram showing a fourth example of a schematic flow of a process for measurement in accordance with a correction value. This example is of a process when, for example, the above-described first example (C 1 ) or second example (C 2 ) of the correction value is used. 
     The terminal device  200  notifies the base station  100  of a capability of interference cancellation of the user (i.e., the terminal device  200 ) (S 641 ). 
     The base station  100  decides on a correction value for the user (i.e., the terminal device  200 ) relating to interference cancellation on the basis of the capability (S 643 ). 
     The terminal device  200  performs measurement with respect to a cell (S 645 ). Then, the terminal device  200  determines a condition for an event that triggers measurement reporting with respect to the cell (S 647 ). 
     When the event has occurred (i.e., when the condition therefor is satisfied), the terminal device  200  performs measurement reporting to the base station  100  (S 649 ). In other words, the terminal device  200  reports a measurement result to the base station  100 . 
     The base station  100  performs measurement with respect to the cell in accordance with the correction value (S 651 ). The base station  100  computes a new measurement result from, for example, the correction value and the aforementioned measurement result. 
     Note that the base station  100  may select a cell for the terminal device  200  on the basis of the new measurement result. The cell may be a target cell for a handover of the terminal device  200 . In other words, the base station  100  may make a decision on a handover for the terminal device  200  on the basis of the new measurement result. Alternatively, the cell may be a secondary cell for the terminal device  200 . The base station  100  may decide addition or deletion of a secondary cell (a secondary component carrier) for the terminal device  200  on the basis of the new measurement result. 
     (d-2) Process Flow (Fifth Example) 
       FIG. 23  is a sequence diagram showing a fifth example of a schematic flow of a process for measurement in accordance with a correction value. This example is of a process when, for example, the above-described third example (C 3 ) of the correction value is used. 
     The terminal device  200  notifies the base station  100  of a capability of interference cancellation of a user (i.e., the terminal device  200 ) (S 661 ). 
     The terminal device  200  performs measurement with respect to cells (S 663 ). Then, the terminal device  200  determines a condition for an event that triggers measurement reporting with respect to the cells (S 665 ). 
     When the event has occurred (i.e., when the condition therefor is satisfied), the terminal device  200  performs measurement reporting to the base station  100  (S 667 ). In other words, the terminal device  200  reports a measurement result to the base station  100 . 
     The base station  100  decides on a set of removal target cells on the basis of the capability and the measurement result (S 669 ). The base station  100  may notify the terminal device  200  and/or a base station in a neighboring cell of the set. 
     Further, the base station  100  decides on a correction value for the user (i.e., the terminal device  200 ) relating to interference cancellation on the basis of the set (S 671 ). 
     The base station  100  performs measurement with respect to the cells in accordance with the correction value (S 673 ). The base station  100  computes a new measurement result from, for example, the correction value and the aforementioned measurement result. 
     Note that the base station  100  may select a cell for the terminal device  200  on the basis of the new measurement result. The cell may be a target cell for a handover of the terminal device  200 . In other words, the base station  100  may make a decision on a handover for the terminal device  200  on the basis of the new measurement result. Alternatively, the cell may be a secondary cell for the terminal device  200 . The base station  100  may decide addition or deletion of a secondary cell (a secondary component carrier) for the terminal device  200  on the basis of the new measurement result. 
     The base station  100  may perform, for example, measurement with respect to the cells in accordance with the correction value as described above. Note that, instead of the base station  100 , another node (for example, a core network node, or the like) may perform measurement with respect to the cells in accordance with the correction value. 
     Measurement is performed in accordance with, for example, a correction value as described above. Thus, measurement can be performed in consideration of, for example, interference cancellation. More specifically, the communication quality is computed in accordance with, for example, whether interference cancellation is performed. Thus, measurement reporting, a handover, and/or addition/deletion of a secondary cell can be performed on the basis of more substantive communication quality. 
     4.2. Inter-Cell Interference Coordination 
     (1) Premise 
     When measurement or measurement reporting is performed in accordance with the above-described user parameter (for example, a user offset, a timer value, or a correction value), better communication quality can be obtained by performing inter-cell interference coordination (ICIC) in consideration of the user parameter. Better communication quality is considered to be obtained particularly in a case of HetNet. 
     Referring to  FIG. 5  again, the base station  100  is, for example, a base station of a macrocell, and a serving cell of the terminal device  200  is, for example, the cell  101  serving as the macrocell in this example. In the cell  101  serving as the macrocell and the small cell  21 , for example, the same frequency band (for example, a component carrier) is used. In this case, the terminal device  200  can receive a signal (i.e., an interfering signal) transmitted by the base station  20 , in addition to a desired signal transmitted by the base station  100  in downlink. 
     Referring to  FIG. 6  again, the base station  100  is, for example, a base station of a small cell, and a serving cell of the terminal device  200  is, for example, the cell  101  serving as the small cell in this example. In the cell  101  serving as the small cell and the macrocell  31 , for example, the same frequency band (for example, a component carrier) is used. In this case, the terminal device  200  can receive a signal (i.e., an interfering signal) transmitted by the base station  30  in addition to a desired signal transmitted by the base station  100  in downlink. 
     In the above-described HetNet, the reception power of a macrocell is greater than the reception power of a small cell. For this reason, it can be said that interference in the small cell from the macrocell is more serious than interference in the macrocell from the small cell. This applies not only to a user having a capability of interference cancellation but also to a user having no capability of interference cancellation. In order to reduce such interference, ICIC is necessary. ICIC is, for example, using different radio resources (for example, resource blocks, sub frames, component carriers, or the like) for cells, or adjusting the reception power of cells. 
     The terminal device  200  can remove a signal having great reception power as interference when the terminal device has a capability of interference cancellation. Thus, applying different strategies for ICIC to a user having a capability of interference cancellation and a user having no capability of interference cancellation is considered to be desirable. 
     Interference from a neighboring cell can depend on a cell selection technique. More specifically, interference from a neighboring cell can depend on, for example, a user offset. When a user offset with respect to a serving cell is great, for example, there is a possibility of a serving cell being easy to select and being selected even in a slightly poor environment. On the other hand, when a user offset with respect to a serving cell is small, a serving cell is more difficult to select and the serving cell is considered to be selected in a favorable environment. Therefore, applying different strategies for ICIC depending on a user offset is considered to be desirable. 
     (2) Determination of Inter-Cell Interference Coordination Based on User Offset 
     The base station  100  (the information acquisition unit  151 ) acquires, for example, an offset for a user (the terminal device  200 ) relating to interference-cancellation, and the offset (i.e., a user offset) is included in a condition for an event that triggers measurement reporting. In addition, the base station  100  (the control unit  153 ) determines whether to perform inter-cell interference coordination (ICIC) for the user on the basis of the offset. Note that, when inter-cell interference coordination for the user is determined, the base station  100  performs inter-cell interference coordination. 
     (a) Offset 
     Detailed description of the user offset is as described above. 
     The user offset in particular includes, for example, an offset with respect to a serving cell of the user (i.e., the terminal device  200 ) and an offset with respect to a neighboring cell. In other words, the base station  100  (the control unit  153 ) determines whether to perform inter-cell interference coordination for the user on the basis of the offset of the serving cell of the user and the offset of the neighboring cell. Note that the serving cell may be a primary cell of the user (i.e., the terminal device  200 ). 
     (b) Capability 
     The base station  100  (the control unit  153 ) also determines whether to perform inter-cell interference coordination (ICIC) for the user further on the basis of, for example, a capability of interference cancellation of the user (i.e., the terminal device  200 ). 
     (c) Example of Determination 
     (c-1) Case in which Serving Cell is Macrocell 
     As a first example, the base station  100  is abase station of a macrocell, and a serving cell of the terminal device  200  is the cell  101  serving as the macrocell as illustrated in the example of  FIG. 5 . An example of a determination in a case will be described below with reference to  FIG. 24 . 
       FIG. 24  is an explanatory diagram for describing an example of determination in the case in which a serving cell of a user is a macrocell. 
     When the serving cell of the user (i.e., the terminal device  200 ) is a macrocell, for example, interference (i.e., interference from the small cell) is small, thus ICIC is unnecessary, and therefore the base station  100  determines not to perform ICIC. 
     There is a case in which a user offset Oup with respect to the serving cell (for example, a primary cell) is greater than a user offset Oun with respect to a neighboring cell.
 
 Oun&lt;Oup   [Math. 63]
 
     In this case, there is a possibility of the reception power of a signal of the neighboring cell (an interfering signal) being greater than the reception power of a signal of the serving cell (a desired signal). Thus, when the terminal device  200  has a capability of interference cancellation, for example, interference cancellation can be performed on the user (i.e., the terminal device  200 ) side. 
     Note that, with regard to magnitude relationships of offsets, not only a user offset but also a frequency offset Of and a cell offset Oc may also be considered.
 
 Ofn+Ocn+Oun&lt;Ojp+Ocp+Oup   [Math. 64]
 
     In addition, the following hysteresis may also be considered.
 
 Ofn+Ocn+Oun−Hys&lt;Ofp+Ocp+Oup   [Math. 65]
 
     (c-2) Case in which Serving Cell is Small Cell 
     As a second example, the base station  100  is a base station of a small cell and a serving cell of the terminal device  200  is the cell  101  serving as the small cell, as illustrated in the example of  FIG. 6 . An example of determination in a case will be described below with reference to  FIG. 25 . 
       FIG. 25  is an explanatory diagram for describing an example of determination in the case in which a serving cell of a user is a small cell. 
     When a serving cell of a user (i.e., the terminal device  200 ) is a small cell, for example, there is a possibility of interference (i.e., interference from a macrocell) being great, and thus ICIC can be necessary. In particular, when, for example, a user offset Oup with respect to a serving cell (for example, a primary cell) is greater than a user offset Onp with respect to a neighboring cell, there is a possibility of the serving cell being selected even in a slightly poor environment. Thus, in this case, if the terminal device  200  has no capability of interference cancellation, the base station  100  determines to perform ICIC for the terminal device  200 . As a result, for example, ICIC is performed. As an example, radio resources (for example, resource blocks) that are not used in a neighboring cell are allocated to the terminal device  200 . As another example, transmission power of a serving cell and a neighboring cell for radio resources to be allocated to the terminal device  200  is adjusted. 
     Note that, when the terminal device  200  has a capability of interference cancellation, interference cancellation can be performed on the user (i.e., the terminal device  200 ) side. 
     (d) Modified Example 
     As a modified example, the base station  100  (the control unit  153 ) may determine whether to perform inter-cell interference coordination for the user (i.e., the terminal device  200 ) further on the basis of a measurement result reported by the user. 
     (d-1) Measurement Result 
     Reception Power 
     The measurement result may be a measurement result of the reception power. The reception power may be RSRP, or other types of power. 
     Measurement Results with Respect to Service Cell and Neighboring Cell 
     The measurement result may include a measurement result with respect to a service cell of the user and a measurement result with respect to a neighboring cell. In other words, the base station  100  may determine whether to perform inter-cell interference coordination for the user further on the basis of the measurement result with respect to the serving cell and the measurement result with respect to the neighboring cell. 
     More specifically, the base station  100  may determine whether to perform inter-cell interference coordination for the user on the basis of the difference between the measurement result with respect to the serving cell (for example, reception power) and the measurement result with respect to the neighboring cell (for example, reception power). 
     Received Power Difference 
     The difference between the reception power P s  with respect to a service cell and the reception power P n  with respect to a neighboring cell (which will be hereinafter referred to as a “reception power difference”) is expressed as P diff  as below.
 
 P   diff   =P   s   −P   N   [Math. 66]
 
     (d-2) Offset Difference 
     A total offset O p,total  with respect to a serving cell (for example, a primary cell) is expressed as below.
 
 O   p,total   =Ofp+Ocp+Oup   [Math. 67]
 
     A total offset O n,total  with respect to a neighboring cell is expressed as below (note that hysteresis need not be included).
 
 O   n,total   =Ofn+Ocn+Oun−Hys   [Math. 68]
 
     The difference between a total offset O p,total  with respect to a serving cell (for example a primary cell) and a total offset O n,total  with respect to a neighboring cell (which will be hereinbelow referred to as a “total offset difference”) is expressed as O diff .
 
 O   diff   =O   p,total   −O   n,total   [Math. 69]
 
     Note that, although the example in which the total offset difference O diff  is used has been described below, a modified example is not limited thereto. Instead of the total offset difference O diff , for example, the difference between a user offset Oup with respect to a serving cell (for example a primary cell) and a user offset Oun with respect to a neighboring cell may be used. 
     (e-3) Example of Determination 
     First Example 
       FIG. 26  is an explanatory diagram for describing a first example of determination according to a modified example. 
     When, for example, a total offset difference O diff  is smaller than a received power difference P diff , a serving cell is favorable to the extent that the serving cell is selected, rather than a neighboring cell even though there is no difference in offsets. Thus, in this case, the base station  100  may determine not to perform ICIC for the terminal device  200 . 
     On the other hand, when a total offset difference O diff  is greater than a received power difference P diff , a serving cell is selected, rather than a neighboring cell due to the difference in offsets. In other words, the serving cell can be said to be no better than the neighboring cell. Thus, when the terminal device  200  (i.e., a user) has no capability of interference cancellation, the base station  100  may determine to perform ICIC for the terminal device  200 . When the terminal device  200  (i.e., a user) has a capability of interference cancellation, interference cancellation is performed on the terminal device  200  side, and thus the base station  100  may determine not to perform ICIC for the terminal device  200 . 
     Second Example 
       FIG. 27  is an explanatory diagram for describing a second example of determination according to the modified example. In this example, only the received power difference is considered, rather than any total offset difference. 
     When the received power difference P diff  is greater than 0, for example, a serving cell is better than a neighboring cell. Thus, the base station  100  may determine not to perform ICIC for the terminal device  200  in this case. 
     On the other hand, when the received power difference P diff  is smaller than 0, a serving cell is no better than a neighboring cell, and it can be said that the serving cell is selected, rather than the neighboring cell due to a difference in offsets. Thus, when the terminal device  200  (i.e., a user) has no capability of interference cancellation, the base station  100  may determine to perform ICIC for the terminal device  200 . When the terminal device  200  (i.e., a user) has a capability of interference cancellation, interference cancellation is performed on the terminal device  200  side, and thus the base station  100  may determine not to perform ICIC for the terminal device  200 . 
     (e) Case in which it is not Possible to Remove Interference from all Neighboring Cells 
     Note that, in the examples of  FIGS. 24 to 27 , interference cancellation is performed on the terminal device  200  (i.e., a user) side without performing inter-cell interference coordination (ICIC), when the terminal device  200  has a capability of interference cancellation. However, an embodiment of the present disclosure is not limited thereto. 
     For example, a maximum number of cells from which interference can be removed by the terminal device  200  may be smaller than the number of neighboring cells from which interference needs to be removed. In this case, interference cancellation may be performed on the maximum number of neighboring cells, and ICIC may be performed on the remaining neighboring cells. In other words, even when the terminal device  200  has a capability of interference cancellation, the base station  100  may determine to perform ICIC for the terminal device  200 . 
     Determination on inter-cell interference coordination is performed as described above. Accordingly, interference between, for example, a serving cell and a neighboring cell of the terminal device  200  can be suppressed. 
     (3) Exchange of Information Between Base Stations 
     The base station  100  (the control unit  153 ) determines, for example, to perform ICIC for the terminal device  200  as described above. In this case, the base station  100  (the control unit  153 ) performs ICIC for the terminal device  200 . The base station  100  (the control unit  153 ) exchanges, for example, information with a base station of a neighboring cell as an operation of ICIC. 
     (a) Provision of Information to Neighboring Base Station 
     When having determined to perform ICIC for the terminal device  200  (i.e., a user), for example, the base station  100  provides information about the terminal device  200  to a base station of a neighboring cell (hereinafter referred to as a “neighboring base station”). The base station  100  requests, for example, ICIC from the neighboring base station, and provides information about the terminal device  200  at the time of request. 
     The information provided to the neighboring base station includes, for example, a user ID, a capability of interference cancellation (for example, presence or absence of a type of interference cancellation, the corresponding type, or the like), the difference in reception power between a serving cell (i.e., a cell  101 ) and the neighboring cell, the difference in offsets between the serving cell (i.e., the cell  101 ) and the neighboring cell, an ID of the serving cell, transmission power of the serving cell, and the like. A specific example of the information provided to a neighboring base station will be described below with reference to  FIG. 28 . 
       FIG. 28  is an explanatory diagram for describing an example of information provided to a neighboring base station for ICIC. Referring to  FIG. 28 , information provided by the base station  100  to the neighboring base station is shown. The base station  100  provides, for example, the number of users for ICIC and information about each user. The information about each user includes a user ID, a capability of interference cancellation, a received power difference, an offset difference, and an ID, and transmission power of a serving cell. 
     With the provision of such information, for example, a determination on execution of ICIC between the base station  100  and a base station of a neighboring cell and/or execution of the ICIC are possible. 
     (b) Response from Neighboring Base Station 
     The neighboring base station determines, for example, whether ICIC is possible in accordance with provision of information from the base station  100  (for example, a request for ICIC), and then responds to the base station  100 . At this time, the neighboring base station provides, for example, information indicating radio resources to be used and the transmission power of the radio resources to the base station  100 . A specific example of the information provided by a neighboring base station will be described below with reference to  FIG. 29 . 
       FIG. 29  is an explanatory diagram for describing an example of information provided by a neighboring base station for ICIC. Referring to  FIG. 29 , information provided by a neighboring base station is shown. The neighboring base station provides, for example, the number of component carriers and information about each component carrier. The information about each component carrier includes a cell ID and information about each sub frame. The information about each subframe indicates resource blocks to be used in the neighboring cell (for example, resource block IDs) and the transmission power of the resource blocks. 
     With the provision of such information, the base station  100  can, for example, allocate radio resources to the terminal device  200  while avoiding interference in the neighboring cell. In other words, ICIC is realized. 
     (4) Process Flow 
       FIG. 30  is a sequence diagram showing an example of a schematic flow of a process for inter-cell interference coordination (ICIC). 
     The terminal device  200  notifies the base station  100  of a capability of interference cancellation of a user (i.e., the terminal device  200 ) (S 681 ). 
     The base station  100  decides on an offset (i.e., a user offset) for the user (i.e., the terminal device  200 ) relating to interference cancellation on the basis of the capability (S 683 ). Then, the base station  100  notifies the terminal device  200  of the user offset (S 685 ). 
     The terminal device  200  performs measurement with respect to a cell (S 687 ). Then, the terminal device  200  determines a condition for an event that triggers measurement reporting with respect to the cell in accordance with the user offset (S 689 ). 
     When the event has occurred (i.e., when the condition therefor is satisfied), the terminal device  200  performs measurement reporting to the base station  100  (S 691 ). In other words, the terminal device  200  reports a measurement result to the base station  100 . 
     The base station  100  determines whether to perform inter-cell interference coordination (ICIC) for the user (i.e., the terminal device  200 ) on the basis of the user offset (and the measurement result) (S 693 ). 
     When ICIC is determined to be performed, the base station  100  requests ICIC from a neighboring base station (a base station of a neighboring cell) (S 695 ). 
     The neighboring base station determines whether to perform ICIC in accordance with the request of the base station  100  (S 697 ), and then responds to the base station  100  (S 699 ). 
     Thereafter, the base station  100  performs scheduling (S 701 ). In other words, the base station  100  allocates radio resources to the terminal device  200  such that interference in the neighboring cell is avoided. 
     5. APPLICATION EXAMPLE 
     The technology of the present disclosure can be applied to various products. The base station  100  may be realized as any type of evolved node B (eNB), for example, a macro eNB, a small eNB, or the like. A small eNB may be an eNB that covers a smaller cell than a macro cell, such as a pico eNB, a micro eNB, or a home (femto) eNB. Alternatively, the base station  100  may be realized as another type of base station such as a node B or a base transceiver station (BTS). The base station  100  may include a main body that controls radio communication (also referred to as a base station device) and one or more remote radio heads (RRHs) disposed in a different place from the main body. In addition, various types of terminals to be described below may operate as the base station  100  by temporarily or semi-permanently executing the base station function. Furthermore, at least some of constituent elements of the base station  100  may be realized in a base station device or a module for a base station device. 
     In addition, the terminal device  200  may be realized as, for example, a mobile terminal such as a smartphone, a tablet personal computer (PC), a notebook PC, a portable game terminal, a portable/dongle type mobile router, or a digital camera, or an in-vehicle terminal such as a car navigation device. In addition, the terminal device  200  may be realized as a terminal that performs machine-to-machine (M2M) communication (also referred to as a machine type communication (MTC) terminal). Furthermore, at least some of constituent elements of the terminal device  200  may be realized in a module mounted in such a terminal (for example, an integrated circuit module configured in one die). 
     5.1. Application Example with Regard to Base Station 
     First Application Example 
       FIG. 31  is a block diagram illustrating a first example of a schematic configuration of an eNB to which the technology of the present disclosure may be applied. An eNB  800  includes one or more antennas  810  and a base station device  820 . Each antenna  810  and the base station device  820  may be connected to each other via an RF cable. 
     Each of the antennas  810  includes a single or multiple antenna elements (such as multiple antenna elements included in an MIMO antenna), and is used for the base station device  820  to transmit and receive radio signals. The eNB  800  may include the multiple antennas  810 , as illustrated in  FIG. 31 . For example, the multiple antennas  810  may be compatible with multiple frequency bands used by the eNB  800 . Although  FIG. 31  illustrates the example in which the eNB  800  includes the multiple antennas  810 , the eNB  800  may also include a single antenna  810 . 
     The base station device  820  includes a controller  821 , a memory  822 , a network interface  823 , and a radio communication interface  825 . 
     The controller  821  may be, for example, a CPU or a DSP, and operates various functions of a higher layer of the base station device  820 . For example, the controller  821  generates a data packet from data in signals processed by the radio communication Interface  825 , and transfers the generated packet via the network interface  823 . The controller  821  may bundle data from multiple base band processors to generate the bundled packet, and transfer the generated bundled packet. The controller  821  may have logical functions of performing control such as radio resource control, radio bearer control, mobility management, admission control, and scheduling. The control may be performed in corporation with an eNB or a core network node in the vicinity. The memory  822  includes RAM and ROM, and stores a program that is executed by the controller  821 , and various types of control data (such as a terminal list, transmission power data, and scheduling data). 
     The network interface  823  is a communication interface for connecting the base station device  820  to a core network  824 . The controller  821  may communicate with a core network node or another eNB via the network interface  823 . In that case, the eNB  800 , and the core network node or the other eNB may be connected to each other through a logical interface (such as an S1 interface and an X2 interface). The network interface  823  may also be a wired communication interface or a radio communication interface for radio backhaul. If the network interface  823  is a radio communication-interface, the network interface  823  may use a higher frequency band for radio communication than a frequency band used by the radio communication interface  825 . 
     The radio communication interface  825  supports any cellular communication scheme such as Long Term Evolution (LTE) and LTE-Advanced, and provides radio connection to a terminal positioned in a cell of the eNB  800  via the antenna  810 . The radio communication interface  825  may typically include, for example, a baseband (BB) processor  826  and an RF circuit  827 . The BB processor  826  may perform, for example, encoding/decoding, modulating/demodulating, and multiplexing/demultiplexing, and performs Various types of signal processing of layers (such as L1, medium access control (MAC), radio link control (RLC), and a packet data convergence protocol (PDCP)). The BB processor  826  may have a part or all of the above-described logical functions instead of the controller  821 . The BB processor  826  may be a memory that stores a communication control program, or a module that includes a processor and a related circuit configured to execute the program. Updating the program may allow the functions of the BB processor  826  to be changed. The module may be a card or a blade that is inserted into a slot of the base station device  820 . Alternatively, the module may also be a chip that is mounted on the card or the blade. Meanwhile, the RF circuit  827  may include, for example, a mixer, a filter, and an amplifier, and transmits and receives radio signals via the antenna  810 . 
     The radio communication interface  825  may include the multiple BB processors  826 , as illustrated in  FIG. 31 . For example, the multiple BB processors  826  may be compatible with multiple frequency bands used by the eNB  800 . The radio communication interface  825  may include the multiple RF circuits  827 , as illustrated in  FIG. 31 . For example, the multiple RF circuits  827  may be compatible with multiple antenna elements. Although  FIG. 31  illustrates the example in which the radio communication interface  825  includes the multiple BB processors  826  and the multiple RF circuits  827 , the radio communication interface  825  may also include a single BB processor  826  or a single RF circuit  827 . 
     In the eNB  800  shown in  FIG. 31 , the information acquisition unit  151  and the control unit  153  described with reference to  FIG. 7  may be implemented by the radio communication interface  825 . Alternatively, at least some of these constituent elements may be implemented by the controller  821 . As an example, a module which includes a part (for example, the BB processor  826 ) or all of the radio communication interface  825  and/or the controller  821  may be mounted in eNB  800 , and the information acquisition unit  151  and the control unit  153  may be implemented by the module. In this case, the module may store a program for causing the processor to function as the information acquisition unit  151  and the control unit  153  (i.e., a program for causing the processor to execute operations of the information acquisition unit  151  and the control unit  153 ) and may execute the program. As another example, the program for causing the processor to function as the information acquisition unit  151  and the control unit  153  may be installed in the eNB  800 , and the radio communication interface  825  (for example, the BB processor  826 ) and/or the controller  821  may execute the program. As described above, the eNB  800 , the base station device  820 , or the module may be provided as a device which includes the information acquisition unit  151  and the control unit  153 , and the program for causing the processor to function as the information acquisition unit  151  and the control unit  153  may be provided. In addition, a readable recording medium in which the program is recorded may be provided. 
     In addition, in the eNB  800  shown in  FIG. 31 , the radio communication unit  120  described with reference to  FIG. 7  may be implemented by the radio communication interface  825  (for example, the RF circuit  827 ). Moreover, the antenna unit  110  may be implemented by the antenna  810 . In addition, the network communication unit  130  may be implemented by the controller  821  and/or the network interface  823 . 
     Second Application Example 
       FIG. 32  is a block diagram illustrating a second example of a schematic configuration of an eNB to which the technology of the present disclosure may be applied. An eNB  830  includes one or more antennas  840 , a base station device  850 , and an RRH  860 . Each antenna  840  and the RRH  860  may be connected to each other via an RF cable. The base station device  850  and the RRH  860  may be connected to each other via a high speed line such as an optical fiber cable. 
     Each of the antennas  840  includes a single or multiple antenna elements (such as multiple antenna elements included in an MIMO antenna), and is used for the RRH  860  to transmit and receive radio signals. The eNB  830  may include the multiple antennas  840 , as illustrated in  FIG. 32 . For example, the multiple antennas  840  may be compatible with multiple frequency bands used by the eNB  830 . Although  FIG. 32  illustrates the example in which the eNB  830  includes the multiple antennas  840 , the eNB  830  may also include a single antenna  840 . 
     The base station device  850  includes a controller  851 , a memory  852 , a network interface  853 , a radio communication interface  855 , and a connection interface  857 . The controller  851 , the memory  852 , and the network interface  853  are the same as the controller  821 , the memory  822 , and the network interface  823  described with reference to  FIG. 31 . 
     The radio communication interface  855  supports any cellular communication scheme such as LTE and LTE-Advanced, and provides radio communication to a terminal positioned in a sector corresponding to the RRH  860  via the RRH  860  and the antenna  840 . The radio communication interface  855  may typically include, for example, a BB processor  856 . The BB processor  856  is the same as the BB processor  826  described with reference to  FIG. 31 , except the BB processor  856  is connected to the RF circuit  864  of the RRH  860  via the connection interface  857 . The radio communication interface  855  may include the multiple BB processors  856 , as illustrated in  FIG. 32 . For example, the multiple BB processors  856  may be compatible with multiple frequency bands used by the eNB  830 . Although  FIG. 32  illustrates the example in which the radio communication interface  855  includes the multiple BB processors  856 , the radio communication interface  855  may also include a single BB processor  856 . 
     The connection interface  857  is an interface for connecting the base station device  850  (radio communication interface  855 ) to the RRH  860 . The connection interface  857  may also be a communication module for communication in the above-described high speed line that connects the base station device  850  (radio communication interface  855 ) to the RRH  860 . 
     The RRH  860  includes a connection interface  861  and a radio communication interface  863 . 
     The connection interface  861  is an interface for connecting the RRH  860  (radio communication interface  863 ) to the base station device  850 . The connection interface  861  may also be a communication module for communication in the above-described high speed line. 
     The radio communication interface  863  transmits and receives radio-signals via the antenna  840 . The radio communication interface  863  may typically include, for example, the RF circuit  864 . The RF circuit  864  may include, for example, a mixer, a filter, and an amplifier, and transmits and receives radio signals via the antenna  840 . The radio communication interface  863  may include multiple RF circuits  864 , as illustrated in  FIG. 32 . For example, the multiple RF circuits  864  may support multiple antenna elements. Although  FIG. 32  illustrates the example in which the radio communication interface  863  includes the multiple RF circuits  864 , the radio communication interface  863  may also include a single RF circuit  864 . 
     In the eNB  830  shown in  FIG. 30 , the information acquisition unit  151  and the control unit  153  described with reference to  FIG. 9  may be implemented by the radio communication interface  855  and/or the radio communication interface  863 . Alternatively, at least some of these constituent elements may be implemented by the controller  851 . As an example, a module which includes a part (for example, the BB processor  856 ) or all of the radio communication interface  855  and/or the controller  851  may be mounted in eNB  830 , and the information acquisition unit  151  and the control unit  153  may be implemented by the module. In this case, the module may store a program for causing the processor to function as the information acquisition unit  151  and the control unit  153  (i.e., a program for causing the processor to execute operations of the information acquisition unit  151  and the control unit  153 ) and may execute the program. As another example, the program for causing the processor to function as the information acquisition unit  151  and the control unit  153  may be installed in the eNB  830 , and the radio communication interface  855  (for example, the BB processor  856 ) and/or the controller  851  may execute the program. As described above, the eNB  830 ; the base station device  850 , or the module may be provided as a device which includes the information acquisition unit  151  and the control unit  153 , and the program for causing the processor to function as the information acquisition unit  151  and the control unit  153  may be provided. In addition, a readable recording medium in which the program is recorded may be provided. 
     In addition, in the eNB  830  shown in  FIG. 32 , the radio communication unit  120  described, for example, with reference to  FIG. 7  may be implemented by the radio communication interface  863  (for example, the RF circuit  864 ). Moreover, the antenna unit  110  may be implemented by the antenna  840 . In addition, the network communication unit  130  may be implemented by the controller  851  and/or the network interface  853 . 
     5.2. Application Example with Regard to Terminal Device 
     First Application Example 
       FIG. 33  is a block diagram illustrating an example of a schematic configuration of a smartphone  900  to which the technology of the present disclosure may be applied. The smartphone  900  includes a processor  901 , a memory  902 , a storage  903 , an external connection interface  904 , a camera  906 , a sensor  907 , a microphone  908 , an input device  909 , a display device  910 , a speaker  911 , a radio communication interface  912 , one or more antenna switches  915 , one or more antennas  916 , a bus  917 , a battery  918 , and an auxiliary controller  919 . 
     The processor  901  may be, for example, a CPU or a system on a chip (SoC), and controls functions of an application layer and another layer of the smartphone  900 . The memory  902  includes RAM and ROM, and stores a program that is executed by the processor  901 , and data. The storage  903  may include a storage medium such as a semiconductor memory and a hard disk. The external connection interface  904  is an interface for connecting an external device such as a memory card and a universal serial bus (USB) device to the smartphone  900 . 
     The camera  906  includes an image sensor such as a charge coupled device (CCD) and a complementary metal oxide semiconductor (CMOS), and generates a captured image. The sensor  907  may include a group of sensors such as a measurement sensor, a gyro sensor, a geomagnetic sensor, and an acceleration sensor. The microphone.  908  converts sounds that are input to the smartphone  900  to audio signals. The input device  909  includes, for example, a touch sensor configured to detect touch onto a screen of the display device  910 , a keypad, a keyboard, a button, or a switch, and receives an operation or an information input from a user. The display device  910  includes a screen such as a liquid crystal display (LCD) and an organic light-emitting diode (OLED) display, and displays an output image of the smartphone  900 . The speaker  911  converts audio signals that are output from the smartphone  900  to sounds. 
     The radio communication interface  912  supports any cellular communication scheme such as LTE and LTE-Advanced, and performs radio communication. The radio communication interface  912  may typically include, for example, a BB processor  913  and an RF circuit  914 . The BB processor  913  may perform, for example, encoding/decoding, modulating/demodulating, and multiplexing/demultiplexing, and performs various types of signal processing for radio communication. Meanwhile, the RF circuit  914  may include, for example, a mixer, a filter, and an amplifier, and transmits and receives radio signals via the antenna  916 . The radio communication interface  912  may also be a one chip module that has the BB processor  913  and the RF circuit  914  integrated thereon. The radio communication interface  912  may include the multiple BB processors  913  and the multiple RF circuits  914 , as illustrated in  FIG. 33 . Although  FIG. 33  illustrates the example in which the radio communication interface  912  includes the multiple BB processors  913  and the multiple RF circuits  914 , the radio communication interface  912  may also include a single BB processor  913  or a single RF circuit  914 . 
     Furthermore, in addition to a cellular communication scheme, the radio communication interface  912  may support another type of radio communication scheme such as a short-distance wireless communication scheme, a near field communication scheme, and a radio local area network (LAN) scheme. In that case, the radio communication interface  912  may include the BB processor  913  and the RF circuit  914  for each radio communication scheme. 
     Each of the antenna switches  915  switches connection destinations of the antennas  916  among multiple circuits (such as circuits for different radio communication schemes) included in the radio communication interface  912 . 
     Each of the antennas  916  includes a single or multiple antenna elements (such as multiple antenna elements included in an MIMO antenna), and is used for the radio communication interface  912  to transmit and receive radio signals. The smartphone  900  may include the multiple antennas  916 , as illustrated in  FIG. 33 . Although  FIG. 33  illustrates the example in which the smartphone  900  includes the multiple antennas  916 , the smartphone  900  may also include a single antenna  916 . 
     Furthermore, the smartphone  900  may include the antenna  916  for each radio communication scheme. In that case, the antenna switches  915  may be omitted from the configuration of the smartphone  900 . 
     The bus  917  connects the processor  901 , the memory  902 , the storage  903 , the external connection interface  904 , the camera  906 , the sensor  907 , the microphone  908 , the input device  909 , the display device  910 , the speaker  911 , the radio communication interface  912 , and the auxiliary controller  919  to each other. The battery  918  supplies power to blocks of the smartphone  900  illustrated in  FIG. 31  via feeder lines, which are partially shown as dashed lines in the figure. The auxiliary controller  919  operates a minimum necessary function of the smartphone  900 , for example, in a sleep mode. 
     In the smartphone  900  shown in  FIG. 33 , the information acquisition unit  241  and the control unit  243  described with reference to  FIG. 8  may be implemented by the radio communication interface  912 . Alternatively, at least some of these constituent elements may be implemented by the processor  901  or the auxiliary controller  919 : As an example, a module which includes a part (for example, the BB processor  913 ) or all of the radio communication interface  912 , the processor  901  and/or the auxiliary controller  919  may be mounted in the smartphone  900 , and the information acquisition unit  241  and the control unit  243  may be implemented by the module. In this case, the module may store a program for causing the processor to function as the information acquisition unit  241  and the control unit  243  (i.e., a program for causing the processor to execute operations of the information acquisition unit  241  and the control unit  243 ) and may execute the program. As another example, the program for causing the processor to function as the Information acquisition unit  241  and the control unit  243  may be installed in the smartphone  900 , and the radio communication interface  912  (for example, the BB processor  913 ), the processor  901  and/or the auxiliary controller  919  may execute the program. As described above, the smartphone  900  or the module may be provided as a device which includes the information acquisition unit  241  and the control unit  243 , and the program for causing the processor to function as the information acquisition unit  241  and the control unit  243  may be provided. In addition, a readable recording medium in which the program is recorded may be provided. 
     In addition, in the smartphone  900  shown in  FIG. 33 , the radio communication unit  220  described, for example, with reference to  FIG. 8  may be implemented by the radio communication interface  912  (for example, the RF circuit  914 ). Moreover, the antenna unit  210  may be implemented by the antenna  916 . 
     Second Application Example 
       FIG. 34  is a block diagram illustrating an example of a schematic configuration of a car navigation device  920  to which the technology of the present disclosure may be applied. The car navigation device  920  includes a processor  921 , a memory  922 , a global positioning system (GPS) module  924 , a sensor  925 , a data interface  926 , a content player  927 , a storage medium interface  928 , an input device  929 , a display device  930 , a speaker  931 , a radio communication interface  933 , one or more antenna switches  936 , one or more antennas  937 , and a battery  938 . 
     The processor  921  may be, for example, a CPU or a SoC, and controls a navigation function and another function of the car navigation device  920 . The memory  922  includes RAM and ROM, and stores a program that is executed by the processor  921 , and data. 
     The GPS module  924  uses GPS signals received from a GPS satellite to measure a position (such as latitude, longitude, and altitude) of the car navigation device  920 . The sensor  925  may include a group of sensors such as a gyro sensor, a geomagnetic sensor, and a barometric sensor. The data interface  926  is connected to, for example, an in-vehicle network  941  via a terminal that is not shown, and acquires data generated by the vehicle, such as vehicle speed data. 
     The content player  927  reproduces content stored in a storage medium (such as a CD and a DVD) that is inserted into the storage medium interface  928 . The input device  929  includes, for example, a touch sensor configured to detect touch onto a screen of the display device  930 , a button, or a switch, and receives an operation or an information input from a user. The display device  930  includes a screen such as a LCD or an OLED display, and displays an image of the navigation function or content that is reproduced. The speaker  931  outputs sounds of the navigation function or the content that is reproduced. 
     The radio communication interface  933  supports any cellular communication scheme such as LET and LTE-Advanced, and performs radio communication. The radio communication interface  933  may typically include, for example, a BB processor  934  and an RF circuit  935 . The BB processor  934  may perform, for example, encoding/decoding, modulating/demodulating, and multiplexing/demultiplexing, and performs various types of signal processing for radio communication. Meanwhile, the RF circuit  935  may include, for example, a mixer, a filter, and an amplifier, and transmits and receives radio signals via the antenna  937 . The radio communication interface  933  may be a one chip module having the BB processor  934  and the RF circuit  935  integrated thereon. The radio communication interface  933  may include the multiple BB processors  934  and the multiple RF circuits  935 , as illustrated in  FIG. 34 . Although  FIG. 34  illustrates the example in which the radio communication interface  933  includes the multiple BB processors  934  and the multiple RF circuits  935 , the radio communication interface  933  may also include a single BB processor  934  or a single RF circuit  935 . 
     Furthermore, in addition to a cellular communication scheme, the radio communication interface  933  may support another type of radio communication scheme such as a short-distance wireless communication scheme, a near field communication scheme, and a radio LAN scheme. In that case, the radio communication interface  933  may include the BB processor  934  and the RF circuit  935  for each radio communication scheme. 
     Each of the antenna switches  936  switches connection destinations of the antennas  937  among multiple circuits (such as circuits for different radio communication schemes) included in the radio communication interface  933 . 
     Each of the antennas  937  includes a single or multiple antenna elements (such as multiple antenna elements included in an MIMO antenna), and is used for the radio communication interface  933  to transmit and receive radio signals. The car navigation device  920  may include the multiple antennas  937 , as illustrated in  FIG. 34 . Although  FIG. 34  illustrates the example in which the car navigation device  920  includes the multiple antennas  937 , the car navigation device  920  may also include a single antenna  937 . 
     Furthermore, the car navigation device  920  may include the antenna  937  for each radio communication scheme. In that case, the antenna switches  936  may be omitted from the configuration of the car navigation device  920 . 
     The battery  938  supplies power to blocks of the car navigation device  920  illustrated in  FIG. 34  via feeder lines that are partially shown as dashed lines in the figure. The battery  938  accumulates power supplied form the vehicle. 
     In the car navigation device  920  shown in  FIG. 32 , the information acquisition unit  241  and the control unit  243  described with reference to  FIG. 10  may be implemented by the radio communication interface  933 . Alternatively, at least some of these constituent elements may be implemented by the processor  921 . As an example, a module which includes a part (for example, the BB processor  934 ) or all of the radio communication interface  933  and/or the processor  921  may be mounted in the car navigation device  920 , and the information acquisition unit  241  and the control unit  243  may be implemented by the module. In this case, the module may store a program for causing the processor to function as the information acquisition unit  241  and the control unit  243  (i.e., a program for causing the processor to execute operations of the information acquisition unit  241  and the control unit  243 ) and may execute the program. As another example, the program for causing the processor to function as the information acquisition unit  241  and the control unit  243  may be installed in the car navigation device  920 , and the radio communication interface  933  (for example, the BB processor  934 ) and/or the processor  921  may execute the program. As described above, the car navigation device  920  or the module may be provided as a device which includes the information acquisition unit  241  and the control unit  243 , and the program for causing the processor to function as the information acquisition unit  241  and the control unit  243  may be provided. In addition, a readable recording medium in which the program is recorded may be provided. 
     In addition, in the car navigation device  920  shown in  FIG. 32 , the radio communication unit  220  described, for example, with reference to  FIG. 10  may be implemented by the radio communication interface  933  (for example, the RF circuit  935 ). Moreover, the antenna unit  210  may be implemented by the antenna  937 . 
     The technology of the present disclosure may also be realized as an in-vehicle system (or a vehicle)  940  including one or more blocks of the car navigation device  920 , the in-vehicle network  941 , and a vehicle module  942 . In other words, the in-vehicle system (or a vehicle)  940  may be provided as a device which includes the information acquisition unit  241  and the control unit  243 . The vehicle module  942  generates vehicle data such as vehicle speed, engine speed, and trouble information, and outputs the generated data to the in-vehicle network  941 . 
     6. CONCLUSION 
     So far, communication devices and processes relating to embodiments of the present disclosure have been described with reference to  FIGS. 4 to 34 . 
     According to the embodiments of the present disclosure, the terminal device  200  includes the information acquisition unit  241  which acquires a parameter for a user relating to interference cancellation and the control unit  243  which performs measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     According to the embodiments of the present disclosure, the base station  100  includes, for example, the information acquisition unit  151  which acquires a parameter for a user relating to interference cancellation and the control unit  153  which notifies the user that performs measurement or measurement reporting with respect to a cell in accordance with the parameter of the parameter. 
     Thus, measurement reporting in consideration of, for example, interference cancellation is possible. 
     So far, exemplary embodiments of the present disclosure have been described with reference to accompanying diagrams, but it is a matter of course that the present disclosure is not limited thereto. It is obvious that a person skilled in the art can conceive various modified examples or altered examples within the scope described in the claims, and it is understood that such examples also belong to the technical scope of the present disclosure. 
     In addition, processing steps in processes of the present specification may not necessarily be executed in, for example, a time series manner in the order described in the flowcharts or sequence diagrams. The processing steps in the processes may also be executed in, for example, a different order from the order described in the flowcharts or sequence diagrams, or may be executed in parallel. 
     In addition, a computer program for causing a processor (for example, a CPU, a DSP, or the like) provided in a device of the present specification (for example, a base station, a base station device or a module for a base station device, or a terminal device or a module for a terminal device) to function as a constituent element of the device (for example, the information acquisition unit, the control unit and/or the like) (in other words, a computer program for causing the processor to execute operations of the constituent element of the device) can also be created. In addition, a recording medium in which the computer program is recorded may also be provided. Further, a device that includes a memory in which the computer program is stored and one or more processors that can execute the computer program (a base station, a base station device or a module for a base station device, or a terminal device or a module for a terminal device) may also be provided. In addition, a method including an operation of the constituent element of the device (for example, the information acquisition unit, the communication control unit, and/or the like) is also included in the technology of the present disclosure. 
     Further, the effects described in this specification are merely illustrative or exemplified effects, and are not limitative. That is, with or in the place of the above effects, the technology according to the present disclosure may achieve other effects that are clear to those skilled in the art based on the description of this specification. 
     Additionally, the present technology may also be configured as below. 
     (1) 
     A device including: 
     an acquisition unit configured to acquire a parameter for a user relating to interference cancellation; and 
     a control unit configured to perform measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     (2) 
     The device according to (1), wherein the parameter is a value corresponding to a capability of interference cancellation of the user. 
     (3) 
     The device according to (2), wherein the parameter is greater when the user has the capability of interference cancellation, and is smaller when the user does not have the capability of interference cancellation. 
     (4) 
     The device according to any one of (1) to (3), wherein the parameter is a value corresponding to the cell or a type of the cell. 
     (5) 
     The device according to (4), wherein the parameter is greater when the cell is a small cell, and is smaller when the cell is a macrocell. 
     (6) 
     The device according to any one of (1) to (5), 
     wherein the parameter is an offset for the user relating to interference cancellation, the offset being included in a condition for an event that triggers measurement reporting, and 
     the control unit performs the measurement reporting with respect to the cell in accordance with the offset. 
     (7) 
     The device according to (6), wherein the offset is a value added to a measurement result under the condition. 
     (8) 
     The device according to (7), wherein the measurement result is reception power of a reference signal or reception quality of a reference signal. 
     (9) 
     The device according to any one of (1) to (5), 
     wherein the parameter is a timer value for the user relating to interference cancellation, the timer value being set for a timer to be used for measurement reporting, and 
     the control unit performs the measurement reporting with respect to the cell in accordance with the timer value. 
     (10) 
     The device according to (9), 
     wherein the timer is a timer that starts when a condition for an event that triggers measurement reporting is satisfied, and 
     the control unit performs the measurement reporting with respect to the cell after the timer expires. 
     (11) 
     The device according to (10), wherein the timer is a timer that is reset when the condition is not satisfied. 
     (12) 
     The device according to any one of (9) to (11), wherein the timer value is greater when a serving cell of the user is a small cell and smaller when the serving cell is a macrocell. 
     (13) 
     The device according to any one of (1) to (5), 
     wherein the parameter is a correction value for the user relating to interference cancellation, the correction value being to be used in measurement of communication quality, 
     the control unit performs the measurement with respect to the cell in accordance with the correction value, and 
     the measurement with respect to the cell is measurement of communication quality of the cell. 
     (14) 
     The device according to (13), wherein the communication quality is a signal-to-noise ratio (SNR), a signal-to-interference-plus-noise ratio (SINR), or reference signal received quality (RSRQ). 
     (15) 
     The device according to (13) or (14), wherein the correction value is a correction value for subtracting an interference component from communication quality in accordance with a capability of interference cancellation of the user. 
     (16) 
     The device according to any one of (13) to (15), wherein the correction value is a value computed from a measurement result with respect to one or more other cells selected in accordance with a capability of interference cancellation of the user. 
     (17) 
     The device according to (16), wherein the one or more other cells are a number of other cells corresponding to the capability. 
     (18) 
     A device including: 
     an acquisition unit configured to acquire a parameter for a user relating to interference cancellation; and 
     a control unit configured to notify the user of the parameter, the user performing measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     (19) 
     The device according to (18), 
     wherein the parameter is an offset for the user relating to interference cancellation, the offset being included in a condition for an event that triggers measurement reporting, and 
     the control unit determines whether to perform inter-cell interference coordination for the user on the basis of the offset. 
     (20) 
     The device according to (19), wherein the offset includes an offset for a serving cell of the user and an offset for a neighboring cell. 
     (21) 
     The device according to (19) or (20), wherein the control unit determines whether to perform the inter-cell interference coordination for the user further on the basis of a capability of interference cancellation of the user. 
     (22) 
     The device according to any one of (19) to (21), wherein the control unit determines whether to perform the inter-cell interference coordination for the user further on the basis of a measurement result reported by the user. 
     (23) 
     The device according to (22), wherein the measurement result includes a measurement result with respect to a serving cell of the user and a measurement result with respect to a neighboring cell. 
     (24) 
     A method including, by a processor: 
     acquiring a parameter for a user relating to interference cancellation; and 
     performing measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     (25) 
     A program causing a processor to execute: 
     acquiring a parameter for a user relating to interference cancellation; and 
     performing measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     (26) 
     A readable recording medium having a program recorded thereon, the program causing a processor to execute: 
     acquiring a parameter for a user relating to interference cancellation; and 
     performing measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     (27) 
     A method including, by a processor: 
     acquiring a parameter for a user relating to interference cancellation; and 
     notifying the user of the parameter, the user performing measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     (28) 
     A program causing a processor to execute: 
     acquiring a parameter for a user relating to interference cancellation; and 
     notifying the user of the parameter, the user performing measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     (29) 
     A readable recording medium having a program recorded thereon, the program causing a processor to execute: 
     acquiring a parameter for a user relating to interference cancellation; and 
     notifying the user of the parameter, the user performing measurement or measurement reporting with respect to a cell in accordance with the parameter. 
     REFERENCE SIGNS LIST 
     
         
           1  system 
           100  base station 
           151  information acquisition unit 
           153  control unit 
           200  terminal device 
           241  information acquisition unit 
           243  control unit