Patent Publication Number: US-11050477-B2

Title: Base station apparatus, terminal apparatus, and wireless communication method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of U.S. application Ser. No. 16/191,747 filed on Nov. 15, 2018, now pending, which is a continuation application of International Application PCT/JP2016/078706 filed on Sep. 28, 2016 and designated the U.S., the entire contents of each are incorporated herein by reference. 
    
    
     FIELD 
     The present invention relates to a base station apparatus, a terminal apparatus, and a wireless communication method. 
     BACKGROUND 
     In a wireless communication system that uses Long Term Evolution (LTE), a base station apparatus performs allocation of a radio resource and determination of a Modulation and Coding Scheme (MCS), based on channel quality information of each terminal apparatus. Accordingly, when transmission in downlink is performed, in order to perform the allocation of a suitable radio resource and the determination of the MCS on each terminal apparatus, the base station apparatus acquires, in advance, feedback information relating to a channel from each terminal apparatus. 
     The feedback information relating to the channel is referred to as Channel State Information (CSI). For example, a Channel Quality Indicator (CQI), a Rank Indicator (RI), a Precoding Matrix Indicator (PMI), a Beam Indicator (BI), a CSI Reference signal resource Indicator (CRI), and the like are included in the CSI. For example, in a case where an error rate is set in advance to 0.1, the terminal apparatus feeds a maximum value of the CQI that does not exceed 0.1 which is an error rate that is set based on a result of channel measurement, as the CQI, back to the base station apparatus. 
     Furthermore, in the wireless communication system that uses LTE, two types of CQIs, a Wideband CQI and a Subband CQI are defined. The Wideband CQI is a CQI that is calculated with an entire band as a unit. Furthermore, the Subband CQI is a CQI that is calculated with contiguous frequency bands as a unit. 
     Moreover, in recent years, research and development of 5 Generation (G) systems as mobile communication systems have been actively conducted. In the 5G system, Ultra Reliable Low Latency Communications (URLLC), as a technology that is added to a normal broadband communication, are given attention. In the wireless communication system that uses the URLLC, for example, in order to cause an application that uses short-delay communication with high reliability to run, it is desirable that data transfer at a lower error rate than ever in a wireless section is realized. In this case, each of the reliability and the delay, which are obtained according to a type of service that is provided, varies, and an error rate also varies according to the type of service that is provided. As services that use the URLLC, for example, examples of dealing with malfunction of a substation and controlling the substation, controlling a power supply system that uses a smart grid technology, providing a virtual presence environment, executing an industrial control application, providing automatic operation or the tactile-sensing Internet, and so forth are considered. 
     It is noted that, in the related art, such as a technology for wireless communication, in the allocation of the radio resource, the terminal apparatus is notified whether non-contiguous radio resources are allocated or contiguous radio resources are allocated in a frequency domain. Furthermore, in the related art, in a case where contiguous carrier aggregation is performed, distribution of the radio resource is performed in a centralized way and in a case where non-contiguous carrier aggregation is performed, the distribution of the radio resource is performed in a distributed way. 
     Examples of the related art include PTL 1: Japanese Laid-open Patent Publication No. 2011-244472, PTL 2: Japanese National Publication of International Patent Application No. 2013-509120. 
     SUMMARY 
     According to an aspect of the invention, a base station apparatus includes: a memory; and processor circuitry coupled to the memory, wherein the processor circuitry is configured to: execute notification processing that comprises transmitting a notification signal of a first information associated with a reliability of data transmission, execute transmission processing that comprises transmitting a reference signal in two or more frequency bands, and execute reception processing that comprises receiving a measurement report that includes a channel quality information of the frequency bands, the channel quality information being derived in accordance with the reliability of the data transmission associated with the first information. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram of a base station apparatus according to an embodiment. 
         FIG. 2  is a block diagram of a terminal apparatus according to the embodiment. 
         FIG. 3  is a diagram for describing selection of a resource set. 
         FIG. 4  is a diagram for describing another example of the selection of the resource set. 
         FIG. 5  is a graph illustrating a relationship between a correlation value and an offset of an SINR. 
         FIG. 6  is a diagram illustrating an example of an MCS selection table. 
         FIG. 7  is a graph for describing a conversion function between the SINR and a CQI. 
         FIG. 8  is a sequence diagram for control of communication that uses URLLC in a wireless communication system according to the embodiment. 
         FIG. 9  is a diagram illustrating an example of data transmission that uses the resource set. 
         FIG. 10  is a diagram illustrating another example of the data transmission that uses the resource set. 
         FIG. 11  is a diagram for describing reliability in a case where data is transmitted using contiguous frequency bands. 
         FIG. 12  is a diagram for describing reliability in the case where data is transmitted using non-contiguous frequency bands. 
         FIG. 13  is a diagram illustrating a hardware configuration of a base station apparatus. 
         FIG. 14  is a diagram illustrating a hardware configuration of a terminal apparatus. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     However, a channel between the terminal apparatus and the base station apparatus changes with time, and reliability of scheduling based on the CSI decreases due to a delay between a timing at which the CSI is measured and a timing at which the base station apparatus actually transmit data to the terminal apparatus. For this reason, there is a concern that the error rate will increase. In a case where the error rate increases, in the wireless communication system, there is a concern that the URLLC which is obtained will be difficult to provide. 
     Particularly, in a short-delay communication such as the URLLC, there is a likelihood that retransmission will not be performed or will be allowed only in a limited manner, and there is a concern that the increase in the error rate will lead directly to a decrease in reliability of communication. 
     Furthermore, although a technology in the related art that notifies whether non-contiguous radio resources or contiguous radio resources in the frequency domain are allocated is used, it is difficult to keep the reliability of the scheduling based on the CSI from decreasing. Furthermore, although the technology of determining which one of the centralized way and the distributed way is used to distribute the radio resource according to a type of carrier aggregation is used in the related art, it is difficult to keep the reliability of the scheduling based on the CSI from decreasing. 
     An object of the technology in the disclosure, which is disclosed in view of the above-described problems, is to provide a base station apparatus, a terminal apparatus, a wireless communication system, and a wireless communication system control method, which efficiently realize high-reliability short-delay communication. 
     Embodiments of a base station apparatus, a terminal apparatus, a wireless communication system, and a wireless communication system control method, which are disclosed in the present application, will be described in detail below with reference to the drawings. It is noted that the base station apparatus, the terminal apparatus, the wireless communication system, and the wireless communication system control method are not limited by the following embodiments. 
     Embodiments 
       FIG. 1  is a block diagram of a base station apparatus according to an embodiment. Furthermore,  FIG. 2  is a block diagram of a terminal apparatus according to the embodiment. A base station apparatus  1  in  FIG. 1  and a terminal apparatus  2  in  FIG. 2  perform wireless communication. The base station apparatus  1  and the terminal apparatus  2  perform any one of data transmission in downlink from the base station apparatus  1  to the terminal apparatus  2  and data transmission in uplink from the terminal apparatus  2  to the base station apparatus  1 . However, in the following description, the data transmission in downlink that uses URLLC will be described below in an emphasized manner. 
     As illustrated in  FIG. 1 , the base station apparatus  1  according to the present embodiment includes a communication control unit  101 , a reception unit  102 , a transmission unit  103 , a signal processing unit  104 , a reliability determination unit  105 , a CSI feedback setting notification unit  106 , and an antenna  107 . 
     The reception unit  102  may receive a wireless signal from the terminal apparatus  2  via the antenna  107 . Then, the reception unit  102  may output the received signal to the signal processing unit  104 . 
     The communication control unit  101  may perform general control of transmission and reception of a signal to and from the terminal apparatus  2 , such as communication scheduling. The communication control unit  101  has a connection processing unit  111 , a resource set determination unit  112 , a radio resource allocation unit  113 , and an MCS selection unit  114 . The communication control unit  101  corresponds to an example of a “transmission setting determination unit.” 
     The connection processing unit  111  may receive input of a signal that is to be used for a call connection processing such as requesting of a call connection, from the signal processing unit  104 . Then, the connection processing unit  111  may perform the call connection processing, such as one that causes a call connection response to be transmitted to the signal processing unit  104 , according to the signal that is to be used for the call connection processing, and may establish a call between the terminal apparatus  2  and the base station apparatus  1 . Subsequently, the terminal apparatus  2  may make a connection to a communication partner via the base station apparatus  1  and an evolved packet core (EPC)  3  that is a core network. Thereafter, the connection processing unit  111  may acquire a data transmission request that is transmitted from a partner to the terminal apparatus  2  or the terminal apparatus  2 . At this point, information on a type of service that is provided to the terminal apparatus  2  may be included in the data transmission request. Then, the connection processing unit  111  may output the information on the type of service that is provided to the terminal apparatus  2 , to the resource set determination unit  112  and the reliability determination unit  105 . 
     The resource set determination unit  112  may store in advance non-contiguous frequency bands that result from division, which are a plurality of frequency bands that are used for communication that uses the URLLC. The resource set determination unit  112  may receive input of the information on the type of service that is provided to the terminal apparatus  2 , from the connection processing unit  111 . Then, the resource set determination unit  112  may determine a set of non-contiguous frequency bands, as a resource set, which is to be used for transmission of a signal to the terminal apparatus  2 , among the non-contiguous frequency bands that are stored, from a size of data that is transmitted for the service that is provided, or the like. 
       FIG. 3  is a diagram for describing selection of the resource set. An available frequency band  301  in  FIG. 3  is a frequency band that is available to the base station apparatus  1  for communication. For example, the resource set determination unit  112  stores in advance non-contiguity frequency bands  311  that are illustrated by an oblique line, of the available frequency band  301  which is illustrated in  FIG. 3 , as frequency bands that are to be used for the communication that uses the URLLC. Then, the resource set determination unit  112  selects a resource set  312  that is illustrated as gray areas in  FIG. 3 , as the set of non-contiguous frequency bands that is to be used for the transmission of the signal to the terminal apparatus  2 , from the non-contiguity frequency bands  311 . At this point, in  FIG. 3 , the resource set determination unit  112  secures, as the resource set  312 , leading areas of all the non-contiguous frequency bands that are included in the non-contiguity frequency bands  311 , respectively, but a method of securing the resource set  312  is not limited to this. For example, the resource set determination unit  112  may select several frequency bands from among non-contiguous frequency bands that are included in the non-contiguity frequency bands  311 , respectively, and may secure areas for the resource set  312  from the selected frequency bands. Furthermore, the resource set determination unit  112  may secure, as the resource set  312 , areas other than the leading areas, of the non-contiguous frequency bands that are included in the non-contiguity frequency bands  311 , respectively. However, it is desirable that a plurality of non-contiguous frequency bands that are included in the resource set  312  are separated by 5 MHz or more from each other. 
     Furthermore, in  FIG. 3 , non-contiguous frequency bands in one-time signal transmission are defined as the resource set, but as long as the frequency band is non-contiguous, the resource set determination unit  112  may determine the resource set using any other method. For example,  FIG. 4  is a diagram for describing another example of the selection of the resource set. As illustrated in  FIG. 4 , a frequency band that is available to the base station apparatus  1  for communication is also present in the time direction, and is expressed as an available frequency band  302 . In this case, the resource set determination unit  112  may define non-contiguous frequency bands  321  and  322  in different times, of the available frequency band  302 , as a resource set. 
     The description is continued with reference back to  FIG. 1 . The resource set determination unit  112  determines a resource set that is used for the transmission of the signal to the terminal apparatus  2 , and then outputs information on the determined resource set to the radio resource allocation unit  113 . 
     The radio resource allocation unit  113  may receive input of information on the resource set that is used for the transmission of the signal to the terminal apparatus  2 , from the resource set determination unit  112 . Then, the radio resource allocation unit  113  may perform allocation of a radio resource to a CSI measurement reference signal from the information on the resource set. Next, the radio resource allocation unit  113  outputs information on a radio resource that is allocated to the CSI measurement reference signal to the signal processing unit  104  and the CSI feedback setting notification unit  106 . Moreover, the radio resource allocation unit  113  determines a CSI transmission timing for the terminal apparatus  2 , and output the determined CSI transmission timing to the CSI feedback setting notification unit  106 . The CSI transmission timing is a timing at which the terminal apparatus  2  which transmits CSI to the base station apparatus  1 , and for example, is set in such a manner that the CSI is periodically transmitted. 
     Furthermore, the radio resource allocation unit  113  acquires the CSI that is transmitted from the terminal apparatus  2 , from the signal processing unit  104 . For example, a CQI, an RI, a PMI, a BI, a CRI, and the like are included in the CSI. Furthermore, either or both of the reception signal power S and the interference power (I+N) may be included. Then, the radio resource allocation unit  113  determines a radio resource that is used for the transmission of the signal to the terminal apparatus  2 , using the acquired CSI and the information on the resource set. Then, the radio resource allocation unit  113  notifies the signal processing unit  104  of the radio resource that is used for the transmission of the signal to the terminal apparatus  2 . 
     The MCS selection unit  114  acquires the CSI that is transmitted from the terminal apparatus  2 , from the signal processing unit  104 . In the present embodiment, in addition to the above-described information, information on a correlation value, and information on a time for measurement of channel information are included in the CSI. At this point, the correlation value is a value indicating whether a relationship among signals that are transmitted using non-contiguous frequency bands, respectively, which are determined as the resource set, is close or remote. Furthermore, the time for the measurement of the channel information is a time at which the terminal apparatus  2  performs the measurement of the channel information that may include a reception signal power, an interference power and a noise power. 
     The MCS selection unit  114  acquires the CQI from the CSI. Then, the MCS selection unit  114  converts the CQI into a Signal-to-Interference plus Noise power Ratio (SINR). The SINR is a value indicating a value indicating a ratio between a power of a desired signal and a power of a signal other than the desired signal, among reception signals. However, in a case where either or both of the reception signal power S and the interference power (I+N) are included instead of the CQI, the MCS selection unit  114  computes the SINR. For example, the SINR may be calculated from the interference power that is included in the CSI, and the reception signal power that is computed from uplink transmission from the terminal apparatus  2 . 
     Furthermore, the MCS selection unit  114  acquires the correlation value from the CSI. At this point, the MCS selection unit  114  may store in advance a function representing a relationship between the correlation value and an offset of the SINR, as on a graph  401  that is illustrated in  FIG. 5 .  FIG. 5  is a graph illustrating the relationship between the correlation value and the offset of the SINR. Then, the MCS selection unit  114  acquires the offset of the SINR that corresponds to the acquired correlation value, using a function of which a plot is the graph  401 . 
     Furthermore, the MCS selection unit  114  may store in advance a function representing a relationship between a delay time and the offset of the SIRN. Then, the MCS selection unit  114  acquires the time for the measurement of the channel information from the CSI. Next, the MCS selection unit  114  calculates an estimated time for data transmission. Then, the MCS selection unit  114  subtracts the time for the measurement of the channel information from the estimated time for data transmission, and calculates a delay time from when the channel information is measured to when the data transmission is performed. At this point, a function representing the relationship between the delay time and the offset of the SIRN is a function that corresponds to a graph representing the relationship between the delay time and the offset of the SIRN, which is the same as that on the graph  401  that is illustrated in  FIG. 5 . 
     At this point, the MCS selection unit  114 , for example, has an MCS selection table  402  that is illustrated in  FIG. 6 .  FIG. 6  is a diagram illustrating an example of the MCS selection table. As illustrated in  FIG. 6 , an MCS is represented by a five-bit value. Then, a modulation scheme and a coding rate are registered in the MCS selection table  402  in a manner that corresponds to each MCS. In the MCS selection table  402  according to the present embodiment, the smaller a number of the MCS, the lower an error occurrence rate and the smaller an amount of data transmission. That is, it may be said that the smaller the number of the MCS, the higher the reliability, but that it takes time to transmit all pieces of transmission target data, thereby increasing the delay. At this point, if channel communication quality is good, the error occurrence rate decreases. Because of this, much more of error occurrence due to modulation or coding may be allowed. Therefore, in a case where the channel communication quality is good, is desirable that the MCS selection unit  114  selects an MCS that has a higher number, thereby shortening the delay. 
     The MCS selection unit  114  may subtract an offset due to the correlation value and the delay time from the SINR that is obtained from the CQI, and calculates a value of the SINR for obtaining the MCS. Next, the MCS selection unit  114  converts the calculated value of the SINR into a five-bit value. Then, the MCS selection unit  114  specifies an MCS that corresponds to the five-bit value that results from the conversion of the value of the SINR, from the MCS selection table  402 . Thereafter, the MCS selection unit  114  notifies the signal processing unit  104  of a modulation scheme and a coding rate that corresponds to the specified MCS. The modulation scheme and the coding rate that are notified by the MCS selection unit  114 , and a radio resource that is used for the transmission of the signal to the terminal apparatus  2 , which is notified by the radio resource allocation unit  113 , are an example of “communication setting.” 
     The description is continued with reference back to  FIG. 1 . The transmission unit  103  receives input of various signals that are used for the call connection processing, such as the call connection response, from the signal processing unit  104 . Then, the transmission unit  103  transmits the various signals, which are used for the call connection processing, to the terminal apparatus  2  via the antenna  107 . Furthermore, the transmission unit  103  receives input of a data transmission signal from the signal processing unit  104  at the time of the data transmission. Then, the transmission unit  103  may transmit the acquired data transmission signal to the terminal apparatus  2  via the antenna  107 . 
     Furthermore, the transmission unit  103  receives input of a CSI feedback setting from the CSI feedback setting notification unit  106 . Then, the transmission unit  103  may transmit the acquired CSI feedback setting to the terminal apparatus  2  via the antenna  107 . 
     The signal processing unit  104  receives transmission instructions for various signals that are used for the call connection processing, such as a transmission instruction for a connection response, from the connection processing unit  111 . Then, according to the transmission instruction, the signal processing unit  104  outputs the various signals that are used for the call connection processing, to the transmission unit  103 . 
     Furthermore, the signal processing unit  104  may receive input of the CSI that is transmitted from the terminal apparatus  2 , from the reception unit  102 . Then, the signal processing unit  104  outputs the acquired CSI to the radio resource allocation unit  113  and the MCS selection unit  114 . 
     Furthermore, the signal processing unit  104  may receive a transmission signal from an EPC  3 . Furthermore, the signal processing unit  104  may receive input of the modulation scheme and the coding rate from the MCS selection unit  114 . Moreover, the signal processing unit  104  may receive a notification of the radio resource that is used for the transmission of the signal to the terminal apparatus  2 , from the radio resource allocation unit  113 . 
     Then, the signal processing unit  104  performs modulation processing and coding processing on the transmission signal that is received from the EPC  3 , using the designated modulation scheme and coding rate. Moreover, the signal processing unit  104  allocates the designated radio resource to the transmission signal. Thereafter, the signal processing unit  104  outputs the transmission signal to the transmission unit  103 . The modulation processing and the coding processing by the signal processing unit  104 , and the allocation of the radio resource are an example of performing “processing on a signal using a transmission setting.” 
     The reliability determination unit  105  may store in advance the reliability that is requested for every service. For example, in the case of a service of dealing with malfunction of a substation and providing control of the substation, the reliability determination unit  105  stores the reliability or the like that is such that an error rate is 10 −4  or less. 
     The reliability determination unit  105  receives input of the information on the type of service that is provided to the terminal apparatus  2 , from the connection processing unit  111 . Then, the reliability determination unit  105  outputs information on the reliability of the service that is provided to the terminal apparatus  2 , to the CSI feedback setting notification unit  106 . 
     The CSI feedback setting notification unit  106  receives input of the information on the radio resource that is allocated to the CSI measurement reference signal, from the radio resource allocation unit  113 . Moreover, the CSI feedback setting notification unit  106  receives input of information on a radio resource that is used by the terminal apparatus  2  for CSI transmission, from the radio resource allocation unit  113 . Furthermore, the CSI feedback setting notification unit  106  receives information on the reliability that is obtained in signal transmission to the terminal apparatus  2 , from the reliability determination unit  105 . 
     Then, the CSI feedback setting notification unit  106  notifies the transmission unit  103  of the CSI feedback setting that may include CSI measurement reference signal information, the CSI transmission timing, and a CSI computation condition, using the acquired information. At this point, a transmission timing, a frequency, a pattern, and the like of the CSI measurement reference signal are included in the CSI measurement reference signal information. Furthermore, the reliability that is to be satisfied for the signal transmission to the terminal apparatus  2  is included in the CSI computation condition. 
     Next, the terminal apparatus  2  will be described with reference to  FIG. 2 . The terminal apparatus  2 , as illustrated in  FIG. 2 , has a reception unit  201 , a signal processing unit  202 , a communication control unit  203 , a transmission unit  204 , a channel measurement unit  205 , a channel information calculation unit  206 , and an antenna  207 . 
     The reception unit  201  may receive a signal that is transmitted from the base station apparatus  1 , via the antenna  207 . Then, the reception unit  201  may output the received signal to the signal processing unit  202 . 
     The signal processing unit  202  receives inputs of the signal that is transmitted from the base station apparatus  1 , from the reception unit  201 . Then, the signal processing unit  202  performs decoding processing and demodulation processing, and the like on the acquired signal. Then, the signal processing unit  202  outputs the signal on which the processing is performed, to the communication control unit  203 . 
     Furthermore, the signal processing unit  202  receives input of data that is transmitted, from the communication control unit  203 . Then, the signal processing unit  202  performs the modulation processing, the coding processing, and the like on acquired data, and generates a transmission signal. Then, the signal processing unit  202  outputs the generated transmission signal to the transmission unit  204 . 
     Furthermore, the signal processing unit  202  outputs data that is included in the signal that is transmitted from the base station apparatus  1 , to the communication control unit  203 . 
     The communication control unit  203  receives input of the signal that is transmitted from the base station apparatus  1 , from the signal processing unit  202 . The communication control unit  203  performs the call connection processing. After a call connection is completed, the communication control unit  203  causes the signal processing unit  202  to transmit a service request to the base station apparatus  1 . 
     Thereafter, when receiving the CSI feedback setting, the communication control unit  203  notifies the channel measurement unit  205  of the CSI measurement reference signal information that is included in the CSI feedback setting. Furthermore, the CSI computation condition is output to the channel information calculation unit  206 . 
     Thereafter, the communication control unit  203  acquires a correlation value of a signal in the non-contiguous frequency bands in the resource set, from the channel information calculation unit  206 . Moreover, the CQI, the RI, the PMI, the BI, and the CRI, which result from systematizing all signals in the non-contiguous frequency bands, respectively, that are included in the resource set, are acquired from the channel information calculation unit  206 . Furthermore, the communication control unit  203  acquires channel information on a signal in each of the non-contiguous frequency bands that are included in the resource set, along with the time for measurement of the channel information, from the channel measurement unit  205 . Thereafter, the communication control unit  203  creates the CSI that may include the CQI, the RI, the PMI, the BI, and the CRI, which result from systematizing all the signals in the non-contiguous frequency bands, respectively, that are included in the resource set, the correlation value of the signal in each of the non-contiguous frequency bands that are included in the resource set, and the time for the measurement of the channel information. Then, the communication control unit  203  outputs the created CSI to the signal processing unit  202 , and causes the created CSI to be transmitted to the base station apparatus  1 . Thereafter, according to a transmission periodicity of the CSI, the communication control unit  203  outputs the CSI to the signal processing unit  202 , and causes the CSI to be transmitted to the base station apparatus  1 . 
     Furthermore, the communication control unit  203  provides data that is acquired from the signal processing unit  202 , in the form of audio, letters, an image, or the like, to an operator. 
     The channel measurement unit  205  receives input of the CSI measurement reference signal information from the communication control unit  203 . Next, the channel measurement unit  205  acquires the transmission timing for the reference signal in each of the non-contiguous frequency bands that are included in the resource set, the frequency, and the pattern, which are included in the CSI measurement reference signal information. Then, using the acquired information, the channel measurement unit  205  acquires the reception signal power, the interference power, and the noise power of the signal in each of the non-contiguous frequency bands that are included in the resource set, from the signal that is received by the reception unit  201 . The reception signal power, the interference power, and the noise power of the signal in each of the non-contiguous frequency bands that are included in the resource set are an example of “individual information.” 
     Moreover, the channel measurement unit  205  acquires a measurement time at which pieces of channel information, such as the reception signal power, the interference power, and the noise power, are measured. Thereafter, the channel measurement unit  205  outputs the reception signal power, the interference power, and the noise power of the signal in each of the non-contiguous frequency bands that are included in the acquired resource set, to the channel information calculation unit  206 . Furthermore, the channel measurement unit  205  outputs the time for the measurement of the channel information to the communication control unit  203 . The measurement time, for example, is expressed as a number of a subframe or a slot for stipulating the transmission time in the base station apparatus  1 . 
     The channel information calculation unit  206  calculates the SINR of the signal in each of the non-contiguous frequency bands that are included in the resource set. In the following, the SINR of the signal in each of the non-contiguous frequency bands that are included in the resource set refers to an “individual SINR.” 
     Next, the channel information calculation unit  206  calculates SINRs of all the non-contiguous frequency bands that are included in the resource set, using the individual SINR. In the following, overall SINR in the non-contiguous frequency bands that are included in the resource set refer to “overall SINR.” For example, the channel information calculation unit  206  may calculate the overall SINR by using a Shannon theorem for a communicational capacity in the individual SINR, or Exponential effective SINR Mapping or Mutual Information based Effective SINR Mapping. Furthermore, the channel information calculation unit  206  may define an average value of individual SINRs as the overall SINR. In this manner, as long as the overall SINR represent a state of reception quality that results from systematizing all the signals in the non-contiguous frequency bands that are included in the resource set, the overall SINR may be obtained in any way. The overall SINR may correspond to an example of the “total information.” 
     At this point, the channel information calculation unit  206  has a conversion function between the SINR and the CQI that are represented by a relationship that is illustrated in  FIG. 7 .  FIG. 7  is a graph for describing the conversion function between the SINR and the CQI. A graph  501  in  FIG. 7  is a graph representing a relationship between the SINR and the CQI for satisfying the reliability that is such that the error rate is 10 −1  or less. Furthermore, a graph  502  is a graph representing the relationship between the SINR and the CQI for satisfying the reliability that is such that the error rate is 10 −5  or less. The graphs  501  and  502  are graphs for converting the SINR into the CQI that has values of 0 to 15 which are expressed in four bits. As illustrated in  FIG. 7 , the higher the reliability, the higher value the SINR to which the CQI correspond has. That is, one that has a higher reliability, of the CQIs that has the same value, corresponds to a state where the reception quality is good. 
     The channel information calculation unit  206 , for example, has the conversion function in accordance with the reliability, in such a manner that a function in a case where the reliability is 10 −1  is plotted on the graph  501  and that a function in a case where the reliability is 10 −5  is plotted on the graph  502 . 
     The channel information calculation unit  206  acquires the reliability that is included in the CSI feedback setting. Next, the channel information calculation unit  206  selects the conversion function between the SINR and the CQI, which corresponds to the acquired reliability. Then, the channel information calculation unit  206  converts the all calculated SINRs into the CQI, using the selected conversion function. 
     Next, the channel information calculation unit  206  calculates the correlation value of each value, by using the correlation function with respect to each of the signals in the non-contiguous frequency bands that are included in the resource set or doing other things. At this point, the channel information calculation unit  206  may obtain a standard deviation as a correlation value. 
     Then, the channel information calculation unit  206  transmits the calculated CQI and correlation value to the communication control unit  203 . At this point, in the present embodiment, the terminal apparatus  2  converts the SINR into a CQI that is expressed in four bits, and notifies the base station apparatus  1  of the CQI as implicit information. However, in a case where transmission of a great amount of data to the base station apparatus  1  is allowable, the terminal apparatus  2  may notify the base station apparatus  1  the SINR as is, as explicit information. Furthermore, instead of the SINR, the terminal apparatus  2  may transmit either the reception signal power S or an interference power I explicitly or implicitly. 
     Next, a flow for control of the communication that uses the URLLC in the wireless communication system according to the present embodiment will be described with reference to  FIG. 8 .  FIG. 8  is a sequence diagram for the control of the communication that uses the URLLC in the wireless communication system according to the embodiment. 
     The connection processing unit  111  of the base station apparatus  1  and the communication control unit  203  of the terminal apparatus  2  may perform the call connection processing that performs mutual communication (Step S 1 ). 
     After call establishment, the communication control unit  203  of the terminal apparatus  2  may transmit the service request including the information on the type of service to the base station apparatus  1  (Step S 2 ). The connection processing unit  111  of the base station apparatus  1  may receive the service request. Then, the connection processing unit  111  outputs the information on the type of service to the resource set determination unit  112  and the reliability determination unit  105 . 
     The resource set determination unit  112  acquires the information on the type of service from the connection processing unit  111 . Then, the resource set determination unit  112  acquires a size of data or the like that is used for the service to be provided, from the size of service, and determines the resource set that has the non-contiguous frequency band (Step S 3 ). Then, the resource set determination unit  112  outputs the acquired reliability to the radio resource allocation unit  113 . The radio resource allocation unit  113  performs allocation of the radio resource to the CSI measurement reference signal from the information on the resource set. Next, the radio resource allocation unit  113  outputs information on the radio resource that is allocated to the CSI measurement reference signal to the signal processing unit  104  and the CSI feedback setting notification unit  106 . Moreover, the radio resource allocation unit  113  determines the CSI transmission timing for the terminal apparatus  2 , and output the determined CSI transmission timing to the CSI feedback setting notification unit  106 . 
     Furthermore, the reliability determination unit  105  acquires the information on the type of service from the connection processing unit  111 . Then, the reliability determination unit  105  determines the reliability that is requested for the service which is provided to the terminal apparatus  2 , for the reliability that is requested for every service that is determined in advance (Step S 4 ). Then, the reliability determination unit  105  outputs the acquired reliability to the CSI feedback setting notification unit  106 . 
     The CSI feedback setting notification unit  106  acquires the information on the radio resource that is allocated to the CSI measurement reference signal and information on the CSI transmission timing, from the radio resource allocation unit  113 . Moreover, the CSI feedback setting notification unit  106  acquires the reliability from the reliability determination unit  105 . Then, the CSI feedback setting notification unit  106  transmits the CSI feedback setting that may include the CSI measurement reference signal information, the CSI transmission timing, and the CSI computation condition, to the terminal apparatus  2 , using the acquired information (Step S 5 ). The communication control unit  203  of the terminal apparatus  2  may receive the CSI feedback setting. Then, the communication control unit  203  notifies the channel measurement unit  205  of the CSI measurement reference signal information. Furthermore, the communication control unit  203  notifies the reliability to the channel information calculation unit  206 . 
     Thereafter, the signal processing unit  104  may transmit the CSI measurement reference signal in each of the non-contiguous frequency bands that are included in the resource set, using the radio resource that is allocated by the radio resource allocation unit  113  (Step S 6 ). 
     The channel measurement unit  205  acquires the CSI measurement reference signal information from the communication control unit  203 . Then, the channel measurement unit  205  measures the channel information using the CSI measurement reference signal information. Moreover, the channel measurement unit  205  acquires the time for the measurement of the channel information (Step S 7 ). Then, the channel measurement unit  205  outputs the reception signal power, the interference power, and the noise power, which are included in the channel information, to the channel information calculation unit  206 . Furthermore, the channel measurement unit  205  outputs the channel information and the time for the measurement of the channel information to the communication control unit  203 . 
     The channel information calculation unit  206  receives input of the reception signal power, the interference power, and the noise power from the channel measurement unit  205 . Then, the channel information calculation unit  206  calculates an individual SINR using the reception signal power, the interference power, and the noise power (Step S 8 ). 
     Moreover, the channel information calculation unit  206  calculates the overall SINR using the calculated individual SINR (Step S 9 ). 
     Next, the channel information calculation unit  206  may acquire the CQI corresponding to the overall SINR, using a function representing the relationship between the SINR and the CQI in accordance with the reliability (Step S 10 ). 
     Moreover, the channel information calculation unit  206  calculates the correlation value between each of the signals in the non-contiguous frequency bands that are included in the resource set, using the correlation function (Step S 11 ). Then, the channel information calculation unit  206  outputs the acquired CQI and the information on the correlation value to the communication control unit  203 . 
     The communication control unit  203  acquires the CQI and the information on the correlation value from the channel information calculation unit  206 . Then, the communication control unit  203  generates the CSI that may include the CQI, the correlation value, and the time for the measurement of the channel information, and the communication control unit  203  may transmit the created CSI to the base station apparatus  1  (Step S 12 ). 
     The MCS selection unit  114  of the base station apparatus  1  acquires the CQI, the correlation value, and a transmission time for the channel information. Then, the CQI is converted into the SINR (Step S 13 ). 
     Next, the MCS selection unit  114  calculates an offset for a margin of the SINR from the correlation value (Step S 14 ). 
     Moreover, the MCS selection unit  114  calculates a delay time from the transmission time for the channel information to the transmission of data to the terminal apparatus  2 . Then, the MCS selection unit  114  calculates the offset for the margin of the SINR from the calculated delay time (Step S 15 ). 
     Then, the MCS selection unit  114  selects an MCS that corresponds to a value that results from subtracting the calculated offset from the SINR, from the MCS selection table  402  (Step S 16 ). Thereafter, the MCS selection unit  114  notifies the signal processing unit  104  of a modulation scheme and a coding rate that corresponds to the selected MCS. The signal processing unit  104  performs the modulation processing and the coding processing on the transmission signal for transmitting data to the terminal apparatus  2 , using the modulation scheme and the coding rate, which are notified from the MCS selection unit  114 . 
     Furthermore, the radio resource allocation unit  113  determines a resource block that is allocated to the data that is to be transmitted to the terminal apparatus  2 , using the resource set. The signal processing unit  104  allocates the resource block, which is designated by the radio resource allocation unit  113 , to the transmission signal (Step S 17 ). Thereafter, the signal processing unit  104  outputs the transmission signal to the transmission unit  103 . 
     Then, the transmission unit  103  may transmit data to the terminal apparatus  2  by using the transmission signal that is acquired from the signal processing unit  104  (Step S 18 ). 
     The signal processing unit  104  and the transmission unit  103  performs the data transmission while repeating selection of the MCS and resource block allocation according to the delay time using the CSI of which the acquisition is completed until a next CSI is sent from the terminal apparatus  2  (Step S 19 ). 
     Thereafter, when a transmission timing for the CIS comes, channel measurement unit  205 , the channel information calculation unit  206 , and the communication control unit  203  of the terminal apparatus  2  acquires the CSI that performs the same processing in each of Steps S 7  to S 11 . Then, the communication control unit  203  may transmit the acquired CSI to the base station apparatus  1  (Step S 20 ). 
     Subsequently, the terminal apparatus  2  periodically transmits the CSI to the base station apparatus  1 . Then, the base station apparatus  1  performs processing in each of Steps S 13  to S 17  using the received CSI, and then repeats the data transmission to the terminal apparatus  2 . 
     At this point, in the following description, the base station apparatus  1  obtains the margin of the SINR using the correlation function and the delay time from the time for the measurement of the channel information to the data transmission, and performs the selection of the MCS. However, if an error of the SINR may be allowed to some degree, the base station apparatus  1  may select the MCS that corresponds to the SINR which is obtained from the notified CQI without using the correlation function and the delay time. Furthermore, the base station apparatus  1  may perform the selection of the MCS using the offset of the SINR that is obtained from one of the correlation function and the delay time. 
     Moreover, a scheme for the data transmission that uses the resource set is described with reference to  FIGS. 9 and 10 .  FIG. 9  is a diagram illustrating an example of the data transmission that uses the resource set. Furthermore,  FIG. 10  is a diagram illustrating another example of the data transmission that uses the resource set. A case where resource blocks #1 and #2 in different non-contiguous frequency bands are set as the resource set is described here. 
       FIG. 9  is a diagram illustrating a configuration in which one transmission point  601  is present and the terminal apparatus  2  receives data from the one transmission point  601 . The transmission point  601  may be the base station apparatus  1  and may be a Remote Radio Head (RRH) that the base station apparatus  1  has. In this case, the transmission point  601  transmits data to the terminal apparatus  2  using the resource blocks #1 and #2. 
     On the other hand, in  FIG. 10 , two transmission points, transmission points  602  and  603 , are present. Then, a configuration is employed in which the terminal apparatus  2  receives data from both the transmission points  602  and  603 . The transmission points  602  and  603 , for example, are different RRHs that one base station apparatus  1  has. Furthermore, in a case where two base station apparatuses  1  perform coordinated communication, the transmission points  602  and  603  may be different base station apparatuses  1 . In this case, for example, the transmission point  602  transmits data to the terminal apparatus  2  using the resource block #1. Furthermore, the transmission point  603  transmits data to the terminal apparatus  2  using the resource block #2. 
     Next, an effect in a case where data is transmitted using the non-contiguous frequency bands will be described with reference to  FIGS. 11 and 12 .  FIG. 11  is a diagram for describing the reliability in a case where data is transmitted using the contiguous frequency bands. Furthermore,  FIG. 12  is a diagram for describing the reliability in the case where data is transmitted using the non-contiguous frequency bands. 
       FIG. 11  illustrates a case where data is transmitted using a plurality of contiguous frequency bands  331  within an available frequency band  330 . The frequency bands  331  are all 10 MHz. A Cumulative Distribution Function (CDF) in a case where data is transmitted using the frequency bands  331  is illustrated in the left portion of  FIG. 11 . On the left portion, an amount of change in reception signal power is plotted on the horizontal axis, and a value of a result of calculation that uses a cumulative distribution function that corresponds to amounts of change in the reception signal power is plotted on the vertical axis. Graphs  701  to  705  are plots of a cumulative distribution function in accordance with the delay time from the time of the measurement of the channel information to the data transmission. The graph  701  is a plot of a cumulative distribution function in a case where the delay time is 1 ms. The graph  702  is a plot of a cumulative distribution function in a case where the delay time is 2 ms. The graph  703  is a plot of a cumulative distribution function in a case where the delay time is 4 ms. The graph  704  is a plot of a cumulative distribution function in a case where the delay time is 8 ms. The graph  705  is a plot of a cumulative distribution function in a case where the delay time is 16 ms. 
     Furthermore,  FIG. 12  illustrates a case where data is transmitted using a plurality of non-contiguous frequency bands  341  within the available frequency band  340 . The frequency bands  341  are all 10 MHz. The Cumulative Distribution Function in the case where data is transmitted using the frequency bands  341  is illustrated in the left portion of  FIG. 12 . On the left portion, an amount of change in reception signal power is plotted on the horizontal axis, and a value of a result of calculation that uses a cumulative distribution function that corresponds to amounts of change in the reception signal power is plotted on the vertical axis. A graph  711  is a plot of the cumulative distribution function in the case where the delay time is 1 ms. A graph  712  is a plot of the cumulative distribution function in the case where the delay time is 2 ms. A graph  713  is a plot of the cumulative distribution function in the case where the delay time is 4 ms. A graph  714  is a plot of the cumulative distribution function in the case where the delay time is 8 ms. A graph  715  is a plot of the cumulative distribution function in the case where the delay time is 16 ms. 
     When the graphs  711  to  715  and the graphs  701  to  705  are compared, the graphs  711  to  715  have the same probability of occurrence as graphs  701  to  705 , respectively, in a state where an amount of change in power is smaller. That is, the amount of change in power is more suppressed in a case where data is transmitted using a plurality of non-contiguous frequency bands  341  than in a case where data is transmitted using a plurality of contiguous frequency bands  331 . In this manner, data is transmitted using the plurality of non-contiguous frequency bands  341 , and thus the amount of change in power in accordance with the delay and the reliability of the communication for which the radio resource that uses the CSI is allocated may be improved. 
     As described above, the wireless communication system according to the present embodiment determines the MCS and the radio resource that is to be allocated to the transmission signal in the resource set, using the channel information that results for systematizing all signals in the non-contiguous frequency bands that are included in the resource set. Accordingly, the MCS in which a large amount of data is transmitted by suppressing error occurrence as much as possible may be selected. Furthermore, data may be transmitted using the non-contiguous frequency bands. Therefore, the wireless communication system according to the present embodiment may efficiently realize high-reliability short-delay communication. 
     Moreover, the base station apparatus according to the present embodiment, provides a margin to the MCS, considering a correlation relationship between the signals in the non-contiguous frequency bands that are included in the resource set, and the delay time from the time for the measurement of the channel information to the data transmission. Accordingly, the base station apparatus according to the present embodiment may select a more suitable MCS, and may contribute to the high-reliability and short-delay of communication. 
     (Hardware Configuration) 
     Next, a hardware configuration of the base station apparatus  1  will be described with reference to  FIG. 13 .  FIG. 13  is a diagram of a hardware configuration of the base station apparatus. 
     As illustrated in  FIG. 13 , the base station apparatus  1  has the antenna  107 , a processor  91 , a memory  92 , a Radio Frequency (RF) circuit  93 , and a network interface  94 . The processor  91  is connected to the memory  92 , the RF circuit  93 , and the network interface  94  with a bus. 
     The network interface  94  is an interface for connecting the EPC  3  and any other base station apparatus  1 . Furthermore, the RF circuit  93  is connected to the antenna  107 . The RF circuit  93  realizes functions the reception unit  102  and the transmission unit  103  that are illustrated in  FIG. 1 . 
     Stored in the memory  92  are various programs that include a program for realizing functions of the communication control unit  101 , the signal processing unit  104 , the reliability determination unit  105 , and the CSI feedback setting notification unit  106 , which are illustrated in  FIG. 1 . 
     The processor  91  reads various programs that are stored in the memory  92  and loads the various programs onto the memory  92  for execution, and thus realizes the functions of the communication control unit  101 , the signal processing unit  104 , the reliability determination unit  105 , and the CSI feedback setting notification unit  106 , which are illustrated in  FIG. 1 . 
     Next, a hardware configuration of the terminal apparatus  2  will be described with reference to  FIG. 14 .  FIG. 14  is a diagram illustrating the hardware configuration of the terminal apparatus. 
     As illustrated in  FIG. 14 , the terminal apparatus  2  has the antenna  207 , a processor  95 , a memory  96 , and an RF circuit  97 . The processor  95  is connected to the memory  96  and the RF circuit  97  with a bus. The RF circuit  97  is connected to the antenna  207 . Then, the RF circuit  97  is realized functions of the reception unit  201  and the transmission unit  204  that are illustrated in  FIG. 2 . 
     Stored in the memory  96  are various programs that include a program for realizing functions of the signal processing unit  202 , the communication control unit  203 , the channel measurement unit  205 , and the channel information calculation unit  206 , which are illustrated in  FIG. 2 . 
     The processor  95  reads various programs that are stored in the memory  96  and loads the various programs onto the memory  96  for execution, and thus realizes the functions of the signal processing unit  202 , the communication control unit  203 , the channel measurement unit  205 , and the channel information calculation unit  206 , which are illustrated in  FIG. 2 . 
     All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.