Patent Publication Number: US-2017374673-A1

Title: Radio device, base station, and terminal device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2016-126048, filed on Jun. 24, 2016, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiment discussed herein is related to a radio device, a base station, and a terminal device. 
     BACKGROUND 
     In recent years, for automated driving of vehicles, there is a proposed assist function in which various kinds of sensors are installed in vehicles and driving of the vehicles is assisted based on the information acquired by the sensors. As the assist function, for example, there is an automatic brake system, or the like. Furthermore, there is a proposed technology that makes good use of driving by collecting information on each of the vehicles, such as driving information acquired by the sensors, or the like, in a data server via a radio communication network and by feeding back information that is used to assist the driving to each of the vehicles. An example of information that is used to assist the driving includes, for example, congestion information on the road on which a vehicle is running, construction information, or the like. 
     Furthermore, it is possible to perform control of selecting the route of the destination based on a global positioning system (GPS) signal or map information and control of, during the vehicle being moving, not only an automatic brake but also a steering wheel operation or an accelerator movement based on the information from sensors mounted on the vehicles. In this way, researches and developments have been promoted in order to implement automated operation in a single vehicle. However, in order for a single vehicle to perform a complete automated operation efficiently, it is preferable to perform analysis and determination including information, such as information on other vehicles or traffic situations of the surroundings, in addition to the information that can be collected by the single vehicle using various kinds of sensors. A lot of communication methods of communication between vehicles and road-to-vehicle communication are proposed. However, for the complete automated operation, in order to share information and to feed back the information to the vehicles, it is desirable to perform communication in real time to share information on a large number of vehicles. 
     Conventionally, if information from a certain terminal device belonging to a radio communication system is shared and used with the other terminal devices, in general, data is collected to a dedicated data server and the information is distributed to each of the terminal devices. Furthermore, as another method of sharing information, there is a method that implements broadcasting between terminal devices by repeating one-to-one direct communication between the terminal devices without using a radio communication system network. Prior art examples are disclosed in International Publication Pamphlet No. WO 2015/046155 and Japanese Laid-open Patent Publication No. 2015-50529. 
     However, when information is shared among a plurality of terminal devices via the data server, a transmission delay is increased because the information is transmitted via a plurality of devices included in the communication network. Thus, if information that is output from a terminal device to another vehicle via the data server, it is difficult to improve the performance of the automated operation of the vehicle. Furthermore, because a communication range is small in one-to-one direct communication between the terminal devices, in order to transmit the information to a distant vehicle, a transmission delay becomes large because one-to-one direct communication is repeated. Consequently, even if one-to-one direct communication is used between the terminal devices, it is also difficult to improve the performance of the automated operation. In this way, in a case of passing through the data server or repeating one-to-one direct communication, it is difficult to transmit information having high urgency, such as information that is used to the automated operation of the vehicle, in a low delay. 
     SUMMARY 
     According to an aspect of an embodiment, a radio device used in a base station that includes the radio device and a radio control device, the radio device includes an extracting unit, an urgent information processing unit, and an inserting unit. The extracting unit extracts a resource block, from among resource blocks included in a signal received from a terminal device, that is previously allocated for transmission of urgent information. The urgent information processing unit that creates, when the urgent information is included in the resource block extracted by the extracting unit, report information including the urgent information that is included in the resource block extracted by the extracting unit. The inserting unit that inserts the report information including the urgent information created by the urgent information processing unit into a resource block that is previously allocated for a report of the urgent 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, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram illustrating an example of a radio communication system; 
         FIG. 2  is a block diagram illustrating an example of a base band unit (BBU); 
         FIG. 3  is a block diagram illustrating an example of a remote radio head (RRH); 
         FIG. 4  is a schematic diagram illustrating an example of arrangement of a physical channel in the uplink; 
         FIG. 5  is a schematic diagram illustrating an example of a reservation area in detail; 
         FIG. 6  is a schematic diagram illustrating an example of urgent information; 
         FIG. 7  is a schematic diagram illustrating an example of arrangement of a physical channel in the downlink; 
         FIG. 8  is a block diagram illustrating an example of a terminal device; 
         FIG. 9  is a sequence diagram illustrating an example of a process performed in the radio communication system; 
         FIG. 10  is a sequence diagram illustrating an example of a process performed in the terminal device when the urgent information is transmitted; 
         FIG. 11  is a sequence diagram illustrating an example of a process performed in the terminal device when the urgent information is received; 
         FIG. 12  is a sequence diagram illustrating an example of a process performed in the radio communication system when a collision occurs in urgent information; 
         FIG. 13  is a schematic diagram illustrating an example of hardware of the BBU; 
         FIG. 14  is a schematic diagram illustrating an example of hardware of the RRH; and 
         FIG. 15  is a schematic diagram illustrating an example of hardware of the terminal device. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Preferred embodiments of the present invention will be explained with reference to accompanying drawings. Furthermore, the radio device, the base station, and the terminal device disclosed in the present application are not limited to the embodiments below. 
     Configuration of a Radio Communication System  1   
       FIG. 1  is a schematic diagram illustrating an example of a radio communication system  1 . The radio communication system  1  according to the embodiment includes an evolved packet core (EPC)  3 , a communication network  4 , a data server  5 , and a base station  6 . The base station  6  includes a BBU  10  and a plurality of RRHs  20   a  and  20   b . The base station  6  provides a service of voice communication or data communication based on the communication standard, such as Long Term Evolution (LTE), or the like. The BBU  10  is connected to the communication network  4 , such as the Internet, or the like, via the EPC  3 . Each of the plurality of the RRHs  20   a  and  20   b  is connected to the BBU  10  via a cable, such as optical fibers, or the like. 
     Furthermore, in a description below, if there is no need to distinguish among each of the plurality of the RRHs  20   a  and  20   b , the RRHs  20   a  and  20   b  are simply referred to as a RRH  20 . Furthermore, in  FIG. 1 , the single base station  6  is connected to the EPC  3 ; however, two or more of the base stations  6  may also be connected to the EPC  3 . Furthermore, in  FIG. 1 , the two RRHs  20  are connected to the single BBU  10 ; however, the single RRH  20  may also be connected to the single BBU  10  or three or more of the RRHs  20  may also be connected. The BBU  10  is an example of a radio control device and each of the RRHs  20  is an example of radio device. 
     The EPC  3  has a role of an interface with the BBU  10  in a core network. Furthermore, the EPC  3  is connected to the communication network  4  and performs communication with the data server  5  via the communication network  4 . The EPC  3  includes, for example, Mobility Management Entity (MME), S-GW (Serving Gateway), Packet Data Network Gateway (P-GW), Policy and Charging Rules Function (PCRF), or the like. 
     The RRH  20   a  performs radio communication with a terminal device  30  mounted on each of vehicles  2   a  to  2   d  that are present in a cell. The RRH  20   b  performs radio communication with the terminal device  30  mounted on each of the vehicles  2   e  to  2   f  that are present in a cell. Furthermore, in a description below, if there is no need to distinguish among each of the vehicles  2   a  to  2   f , the vehicles  2   a  to  2   f  are simply referred to as a vehicle  2 . Furthermore, the number of the vehicles  2  present in the cell of each of the RRHs  20  is not limited to the number illustrated in  FIG. 1 . 
     The BBU  10  performs communication, via each of the RRHs  20 , with the terminal devices  30  mounted on the vehicles  2  present in the cells of the RRH  20  and performs communication with the data server  5  via both the EPC  3  and the communication network  4 . Furthermore, the BBU  10  may also perform communication with the other BBU  10  via the EPC  3  or via an intra-base station communication interface provided in the BBU  10 . 
     The terminal device  30  is mounted on each of the vehicles  2 . The terminal devices  30  mounted on the vehicles  2  perform, in the cells of the respective RRHs  20 , radio communication with the RRHs  20  and perform communication with the BBU  10  via the respective RRHs  20 . Then, each of the terminal devices  30  performs communication with the other terminal device  30  or the data server  5  via the BBU  10 . 
     Here, if the terminal device  30  mounted on the vehicle  2  (for example, vehicle  2   a ) included in the cell detects the occurrence of information having high urgency (hereinafter, referred to as “urgent information”), such as information used for autonomous control of the vehicle  2 , or the like, the terminal device  30  conveys the urgent information to the terminal devices  30  mounted on the other vehicles  2  (for example, the vehicles  2   b  to  2   d ). For example, if the urgent information is conveyed via the data server  5  that is connected to the communication network  4 , a transmission delay or fluctuation of transfer time occurs in both the EPC  3  and the communication network  4 . Furthermore, if the urgent information is conveyed due to the repetition of one-to-one direct communication, the urgent information transmitted from the terminal device  30  mounted on, for example, the vehicle  2   a  is transferred by each of the terminal devices  30  mounted on the vehicles  2   b  and  2   c  and delivered to the terminal device  30  mounted on the vehicle  2   d . In this case, a delay occurs due to transfers performed twice. 
     In contrast, in the embodiment, the RRH  20  detects the urgent information sent from the terminal device  30  mounted on the vehicle  2  in the cell; reloads, in the RRH  20 , the detected urgent information to a downlink transmission signal; and reports to the terminal device  30  mounted on each of the vehicles  2  included in the cells. Consequently, the urgent information transmitted from the terminal device  30  mounted on the vehicle  2  in the cell is conveyed to all of the terminal devices  30  mounted on the vehicles  2  in the cells at a single transfer. Consequently, the RRH  20  according to the embodiment can convey the information that has high urgency and that is transmitted from the certain terminal device  30  to the other terminal devices  30  in a low delay. 
     Furthermore, the RRH  20  according to the embodiment can be implemented by adding functions to the RRHs that are arranged in a wide area in a distributed manner in order to provide a service of voice communication or a service of data communication based on, for example, the communication standard, such as LTE, or the like. Thus, if the RRHs  20  according to the embodiment are used, it is possible to provide a low delay transmission service of urgent information to a wider area at lower cost when compared in a case of newly arranging a dedicated base station in order to transmit the urgent information in a low delay. 
     BBU  10   
       FIG. 2  is a block diagram illustrating an example of the BBU  10 . The BBU  10  according to the embodiment includes, for example, as illustrated in  FIG. 2 , a RRH interface unit  11 , a communication control unit  12 , and a network interface unit  13 . 
     The RRH interface unit  11  is an interface for performing wired communication with each of the RRHs  20 . The RRH interface unit  11  performs communication with each of the RRHs  20  via a cable, such as optical fibers, or the like, by using an optical signal based on, for example, the communication standard, such as the Common Public Radio Interface (CPRI), or the like. The network interface unit  13  is an interface for performing wired communication with the EPC  3 . 
     The communication control unit  12  includes a call control unit  120  and a protocol management unit  121 . The call control unit  120  performs, by using previously set call setting, overall control of a call process related to radio communication or voice communication, such as control of the communication resources that are used for the communication with the terminal devices  30 . For example, the call control unit  120  performs a process to be performed in a layer  1  to a layer  3  between the terminal devices  30  via each of the RRHs  20 . An example of the process performed in the layer  1  includes, for example, demodulation or decoding of the signal received from the terminal device  30 , encoding or modulation of the signal transmitted to the terminal device  30 , mapping of resource blocks, or the like. Furthermore, an example of the process performed in a layer  2  includes, for example, control of retransmission, data compression, or the like. Furthermore, an example of the process performed in the layer  3  includes, for example, a process related to a handover of the terminal devices  30 , a process related to a measurement report from the terminal device  30 , management of a Radio Resource Control (RRC) connection, or the like. 
     The call control unit  120  performs the processes to be performed in the layer  1  to the layer  3  on the signal transmitted from the terminal device  30  via the RRH interface unit  11  and then outputs the processed signal to the network interface unit  13 . Furthermore, the call control unit  120  performs the processes to be performed in the layer  1  to the layer  3  on the signal transmitted from the data server  5 , the other BBU  10 , or the like via the EPC  3  and then outputs the processed signal to the RRH interface unit  11 . 
     Furthermore, the call control unit  120  manages, for each of the RRHs  20 , the information on the terminal devices  30  that are included in the cell of the respective RRHs  20 . Then, the call control unit  120  allocates, for each of the RRHs  20 , each of the plurality of the resource blocks that are previously allocated, in the uplink, for transmission of the urgent information to each of the terminal devices  30  in the cell of the respective RRHs  20 . The resource block is the radio resource specified for each combination of the time zone and the frequency band. In the embodiment, for each uplink subframe, a plurality of resource blocks that are to be used for transmission of urgent information is previously allocated. 
     The call control unit  120  allocates, in each of the subframes, for each of the RRHs  20 , the resource blocks that are used for transmission of urgent information by the terminal devices  30  included in the cell of the respective RRHs  20  to each of the terminal devices  30  such that the number of terminal devices  30  allocated to the same resource block can be reduced. Consequently, it is possible to prevent the same resource block from being used for the transmission of the urgent information by the plurality of the terminal devices  30 . The information related to the allocation of the resource blocks is sent, as a notification, to each of the terminal devices  30  by using a downlink control channel. 
     When establishing a connection between the terminal devices  30 , the protocol management unit  121  determines the content of the signal received from the terminal device  30 . Then, the protocol management unit  121  performs a process of generating a signal or the like in accordance with the protocol corresponding to the content of the determined signal. For example, in response to the signal transmitted from the terminal device  30 , the protocol management unit  121  generates, in a random access procedure, a signal of RACH response, RRC connection setup, or the like and then outputs the generated signal to the call control unit  120 . 
     RRH  20   
       FIG. 3  is a block diagram illustrating an example of the RRH  20 . The RRH  20  includes, for example, as illustrated in  FIG. 3 , an antenna  21 , a radio processing unit  22 , a communication control unit  23 , and a BBU interface unit  24 . The BBU interface unit  24  is an interface for performing wired communication with the BBU  10 . The BBU interface unit  24  performs communication with the BBU  10  via a cable, such as optical fibers, or the like, by using an optical signal based on the communication standard, such as CPRI, or the like. 
     The radio processing unit  22  includes a receiving unit  220  and a transmitting unit  221 . The receiving unit  220  receives the radio signal output from the terminal device  30  via the antenna  21 . Then, the receiving unit  220  generates a baseband reception signal by performing a process of amplification, down-conversion, and the like on the received signal. Then, the receiving unit  220  outputs the generated baseband reception signal to the communication control unit  23 . 
     The transmitting unit  221  generates a signal having a radio frequency (RF) band by performing a process of up-conversion, amplification, and the like on the baseband transmission signal that is output from the communication control unit  23 . Then, the transmitting unit  221  transmits the generated signal having the RF band to the terminal device  30  via the antenna  21 . 
     The communication control unit  23  includes a protocol management unit  230  and an urgent information processing unit  233 . The protocol management unit  230  includes an extracting unit  231  and an inserting unit  232 . The extracting unit  231  performs Fourier transformation on the signal received from the terminal device  30 . Then, the extracting unit  231  extracts a resource block that is previously allocated for transmission of urgent information from among the resource blocks included in the signal that has been subjected to Fourier transformation. Then, the extracting unit  231  outputs the extracted resource block for the transmission of the urgent information to the urgent information processing unit  233 . 
     In the following, an uplink physical channel transmitted from the terminal device  30  will be described.  FIG. 4  is a schematic diagram illustrating an example of arrangement of a physical channel in the uplink. In the uplink, for example, as illustrated in  FIG. 4 , a single frame is constituted by a plurality of subframes in the time direction. In the embodiment, 10 subframes with the frame numbers of #0 to #9 are included in a single frame. The length of the single frame is, for example, 10 milliseconds and the length of each of the subframes is, for example, 1 millisecond. 
     In the frame, for example, as illustrated in  FIG. 4 , resources, such as PUCCH, PRACH, SRS, PUSCH, and the like are provided. PUCCH is the abbreviation of a physical uplink control channel, PRACH is the abbreviation of a physical random access channel, SRS is the abbreviation of a sounding reference signal, and PUSCH is the abbreviation of a physical uplink shared channel. In the embodiment, in each of the subframes, the resource that is used for transmission of the urgent information sent from the terminal device  30  is previously allocated in the PUSCH resource. The resource that is previously allocated for the transmission of the urgent information sent from the terminal device  30  is indicated, in  FIG. 4 , by a reservation area  40  for each of the subframes. 
     The detail of the reservation area  40  in each of the subframes is such as that illustrated in, for example,  FIG. 5 .  FIG. 5  is a schematic diagram illustrating an example of the reservation area  40  in detail. The reservation area  40  in each of the subframe is, for example, as illustrated in  FIG. 5 , divided into a plurality of division areas  41 - 1  to  41 - n  in the frequency direction. Furthermore, in the following, if there is no need to distinguish among each of the plurality of the division areas  41 - 1  to  41 - n , the division areas  41 - 1  to  41 - n  are simply referred to as division area  41 . 
     In the embodiment, each of the division areas  41  is the radio resource that has the time corresponding to several symbols in the time direction and that has the frequency band corresponding to several subcarriers in the frequency direction. In the embodiment, in each of the subframes, a plurality of the division areas  41  that are present in the same time zone is allocated in the frequency; however, as another example, the plurality of the division areas  41  may also be allocated in the frequency direction and the time direction. Each of the division areas  41  is an example of the resource block. 
     Each of the division areas  41  is allocated to each of the terminal devices  30  in the cell of the RRH  20  for the transmission of the urgent information. Each of the division areas  41  stores therein, for example, data on the urgent information including the information illustrated in  FIG. 6 .  FIG. 6  is a schematic diagram illustrating an example of the urgent information. In the embodiment, the urgent information includes therein, for example, as illustrated in  FIG. 6 , the information, such as the “notification type”, the “state”, the “movement state of a vehicle”, the “location of occurrence”, and the “time of occurrence”. The “notification type” is information indicating the type of, for example, sudden braking, sudden acceleration, abrupt steering operation, detection of driver&#39;s drowsiness, unintentional engine stop, stop on an expressway, or the like. The “state” is information indicating the degree of the type associated with, for example, the “notification type”. The “movement state of a vehicle” is information indicating the movement state of the vehicle when urgent information is generated. The “location of occurrence” is information indicating the location of the vehicle when the urgent information is generated. The “time of occurrence” is the time at which the urgent information occurs. 
     In the embodiment, the data size of each of the items in the urgent information is about 20 bytes in total at most. Thus, in the embodiment, as each of the division areas  41 , the resource with the size that can store therein the data with about at least 20 bytes is secured in the PUSCH resource. 
     A description will be continued by referring back to  FIG. 3 . The urgent information processing unit  233  determines whether, regarding each of the resource blocks output from the extracting unit  231 , urgent information is included in the resource blocks. If the urgent information is included, the urgent information processing unit  233  creates report information including the urgent information for each resource block. Then, the urgent information processing unit  233  outputs the created report information to the inserting unit  232 . Furthermore, if the plurality of the terminal devices  30  transmits urgent information by using the same resource block, the data in the resource block is destroyed due to collision. Consequently, the urgent information processing unit  233  fails to decode the data in the subject resource block. In also a case in which the urgent information processing unit  233  fails to decode the data in the resource block, the urgent information processing unit  233  determines that the urgent information is not included in the resource block. 
     The inserting unit  232  inserts the report information including the urgent information created by the urgent information processing unit  233  into the resource block that is previously allocated for a report of the urgent information. At this time, the inserting unit  232  inserts the report information including the urgent information that is included in the resource block extracted by the extracting unit  231  into the resource block that is used for the report and that is reported first. Then, the extracting unit  231  performs inverse Fourier transformation on the signal in which the urgent information is inserted in the resource block that is used for the report of the urgent information. Then, the inserting unit  232  outputs the signal that has been subjected to inverse Fourier transformation to the transmitting unit  221 . The signal output from the inserting unit  232  is transmitted to the terminal device  30  in the cell by the transmitting unit  221 . 
     In the following, the downlink physical channel transmitted to the terminal device  30  will be described.  FIG. 7  is a schematic diagram illustrating an example of arrangement of a physical channel in the downlink. In the downlink, for example, as illustrated in  FIG. 7 , a single frame is constituted by a plurality of subframes in the time direction. In the embodiment, 10 subframes with the frame numbers of #0 to #9 are included in a single frame. The length of the single frame is, for example, 10 milliseconds and the length of each of the subframes is, for example, 1 millisecond. 
     In the frame, for example, as illustrated in  FIG. 7 , resources, such as PBCH, P-SCH/S-SCH, PDCCH, and PDSCH are contained. PBCH is the abbreviation of a physical broadcast channel and P-SCH/S-SCH is the abbreviation of a primary-synchronization channel/secondary-synchronization channel. Furthermore, PDCCH is the abbreviation of a physical downlink control channel and PDSCH is the abbreviation of a physical downlink shared channel. 
     In the embodiment, in the PDSCH resources in each of the subframes, the resource that is used to report the urgent information to the terminal device  30  in the cell is previously allocated. The resource that is previously allocated for a report of the urgent information to be sent to the plurality of the terminal devices  30  is indicated, in  FIG. 7 , by a reservation area  42  for each subframe. For example, similarly to the reservation area  40  illustrated in  FIG. 5 , the reservation area  42  in each of the subframes is divided into the plurality of the division areas  41 - 1  to  41 - n  in the frequency direction. 
     In the embodiment, each of the terminal devices  30  present in the cell of the RRH  20  monitors, in each of the subframes, all of the division areas  41  in the reservation area  42 . Consequently, if the inserting unit  232  stores the urgent information in one of the division areas  41 , the terminal devices  30  in the cell can acquire the urgent information. 
     Furthermore, in the RRH  20 , the process of identifying and extracting a predetermined resource block from among the resource blocks that are included in the signal transmitted from the terminal device  30  and the process of inserting a predetermined signal into a predetermined resource block in the signal to be transmitted to the terminal device  30  is one of the processes performed in the layer  1 . Namely, in the embodiment, the RRH  20  performs the process in the layer  1 . 
     Terminal Device  30   
       FIG. 8  is a block diagram illustrating an example of the terminal device. The terminal device  30  according to the embodiment acquires the state of the vehicle  2  on which the terminal device  30  is mounted, performs operation control of the subject vehicle  2 , notifies the RRH  20  of urgent information, and acquires the urgent information from the RRH  20 . The terminal device  30  includes, for example, as illustrated in  FIG. 8 , a communication management unit  32 , a vehicle body control unit  36 , and an antenna  31 . 
     The vehicle body control unit  36  acquires the state of the vehicle  2  on which the terminal device  30  is mounted and performs operation control of the vehicle  2 . The vehicle body control unit  36  includes a control unit  360  and a sensor unit  361 . 
     The sensor unit  361  monitors the operation state of the vehicle  2 , such as the operation of a brake, the speed of the vehicle  2 , or the like and acquires the operation information on the vehicle  2 . Then, the sensor unit  361  outputs the operation information on the vehicle  2  to the control unit  360 . For example, the sensor unit  361  outputs, to the control unit  360 , the information on the location, the time, the traveling direction, the speed, the level of the brake, and the like of the vehicle  2  as the operation information on the vehicle  2 . 
     If the operation information on the vehicle  2  is output from the sensor unit  361 , the control unit  360  determines, based on the subject operation information, whether autonomous control of the vehicle  2  is performed. If it is determined that autonomous control is performed, the control unit  360  performs autonomous control that controls each of the units in the vehicle  2  in accordance with the operation information on the vehicle  2 . 
     For example, the control unit  360  acquires, from the sensor unit  361 , the operation information that includes therein both information on the distance between the vehicle  2  having mounted thereon the terminal device  30  and the other vehicle  2  and speed. Then, if the distance between the vehicles is smaller than a predetermined distance and the speed thereof is equal to or greater than a predetermined speed, the control unit  360  decides to perform control such that a brake is applied. Then, the control unit  360  controls the member that is included in the vehicle  2  and that is related to the brake such that the brake is applied. 
     Furthermore, if the control unit  360  performs autonomous control, the control unit  360  notifies an urgent information processing unit  342  of the notification of the autonomous control. The control unit  360  may also notify the urgent information processing unit  342  by adding the information acquired from the sensor unit  361  to the operation information on autonomous control. 
     At this point, in the embodiment, every time the control unit  360  performs the autonomous control, the control unit  360  sends a notification to the urgent information processing unit  342  and allows the urgent information processing unit  342  to start notifying the urgent information; however, the control unit  360  may also determines the notification of the urgent information, in addition to the execution of the autonomous control. For example, the control unit  360  may also determine whether a notification of the urgent information is sent based on the control of the vehicle  2  and may also notify the urgent information processing unit  342  of the urgent information based on the subject determination result. For example, if a brake with the intensity equal to or greater than that previously defined based on the autonomous control is applied to the vehicle  2 , the control unit  360  may also notify the urgent information processing unit  342  of the notification of the urgent information. 
     Furthermore, for example, the control unit  360  may also decide to perform notification of the urgent information by using the acquired operation information on the vehicle  2  independent of the execution of the autonomous control. For example, if the speed of the vehicle  2  acquired from the sensor unit  361  exceeds a predetermined speed and if the level of the brake exceeds a predetermined intensity of the brake, the control unit  360  may also notify the urgent information processing unit  342  of the urgent information. 
     Furthermore, if the information on the autonomous control is output from the urgent information processing unit  342 , the control unit  360  controls each of the units in the vehicle  2  based on the information on the subject autonomous control. 
     The communication management unit  32  transmits and receives the urgent information. The communication management unit  32  includes a radio processing unit  33 , a communication control unit  34 , and a user interface unit  35 . 
     The user interface unit  35  includes an output device, such as a liquid crystal monitor, or the like, and includes an input device, such as a touch panel, or the like. The user interface unit  35  outputs, to the communication control unit  34 , the information that is input from a user via the input device. Furthermore, the user interface unit  35  outputs the information output from the communication control unit  34  to the output device. 
     The radio processing unit  33  is an interface for radio communication with the RRH  20 . The radio processing unit  33  includes a receiving unit  330  and a transmitting unit  331 . 
     The receiving unit  330  receives a radio signal that is output from the RRH  20  via the antenna  31 . Then, the receiving unit  330  generates a baseband reception signal by performing a process of amplification, down-conversion, and the like on the received signal. Then, the receiving unit  330  outputs the generated baseband reception signal to the communication control unit  34 . 
     The transmitting unit  331  generates a signal having the RF band by performing the process of up-conversion, amplification, and the like on the baseband signal output from the communication control unit  34 . Then, the transmitting unit  331  transmits the generated signal having the RF band to the RRH  20  via the antenna  31 . 
     The communication control unit  34  includes a call control unit  340 , a protocol management unit  341 , and the urgent information processing unit  342 . The call control unit  340  performs a process in the layer  1  to the layer  3  in communication with the BBU  10  via the RRH  20 . For example, by using previously set call setting, the call control unit  340  performs overall control of a call process related to radio communication, such as control of communication resource, that is used for communication with the BBU  10  via the RRH  20 . 
     Furthermore, the call control unit  340  extracts, from among the resource blocks included in the signal received from the RRH  20 , both the resource block that is previously allocated for a report of the urgent information and a resource block that stores therein the data that is addressed to the own device and that is other than the urgent information. The call control unit  340  outputs, to the urgent information processing unit  342 , the extracted resource block that is used for the report of the urgent information. The resource block used, in a downlink, for the report of the urgent information is arranged in, for example, as described with reference to  FIG. 7 , the reservation area  42  in each of the subframes. Furthermore, the call control unit  340  performs a process based on the data in the resource block that stores therein the data that is addressed to the own device and that is other than the urgent information and then outputs the execution result to the user interface unit  35 . 
     Furthermore, the call control unit  340  performs a predetermined process on the information from a user via the user interface unit  35  and inserts the processed data into the resource block that is allocated to the own device and that is used to transmit data other than the urgent information. Furthermore, if the urgent information is output from the urgent information processing unit  342 , the call control unit  340  inserts the subject urgent information into the resource block that is allocated to the own device and that is used to transmit the urgent information. The signal in which the urgent information and data other than the urgent information are inserted into the predetermined resource blocks by the call control unit  340  is output to the transmitting unit  331  and is transmitted to the RRH  20  by the transmitting unit  331 . The resource block, in the uplink, that is used to transmit the urgent information is provided in, for example, as described with reference to  FIG. 4 , the reservation area  40  in each of the subframes. In the reservation area  40  in each of the subframes, the information in the division areas  41  that are allocated to the own device is notified from the BBU  10  via the RRH  20 . 
     When the protocol management unit  341  establishes a connection with the BBU  10  via the RRH  20 , the protocol management unit  341  determines the content of the signal received from the BBU  10  via the RRH  20 . Then, the protocol management unit  341  performs a process, such as generating a signal, or the like, in accordance with the protocol corresponding to the content of the determined signal. For example, the protocol management unit  341  generates, in the procedure of the random access, a signal, such as a RACH preamble, an RRC connection request, or the like, and then outputs the generated signal to the call control unit  340 . 
     The urgent information processing unit  342  receives a notification of the autonomous control from the control unit  360 . In the notification of the autonomous control, information on, for example, the time of sudden braking, the traveling direction, the speed, the level of the braking, and the like are included. The urgent information processing unit  342  creates urgent information from the information that is included in the notification of the autonomous control acquired from the control unit  360 . The urgent information processing unit  342  contains, in the created urgent information, as the identification information on the terminal device  30  that is the transmission source, the identification information on the own device. Then, the urgent information processing unit  342  transmits the created urgent information to the base station  6  by using the resource block that is previously allocated to the own device and that is used to transmit the urgent information. Specifically, the urgent information processing unit  342  outputs the created urgent information to the call control unit  340 . The call control unit  340  inserts the urgent information output from the urgent information processing unit  342  into the resource block that is allocated to the own device used for transmission of the urgent information. The signal in which the data on the urgent information is inserted into the predetermined resource block by the call control unit  340  is output to the transmitting unit  331  and is transmitted to the base station  6  by the transmitting unit  331 . 
     Furthermore, if the data in the resource block for a report of the urgent information is output from the call control unit  340 , the urgent information processing unit  342  determines, for each resource block, whether the urgent information is included in the data in the resource block. If the urgent information is included in the data in the resource block, the urgent information processing unit  342  refers to the identification information that is related to the terminal device  30  functioning as the transmission source and that is included in the urgent information and determines whether the subject urgent information is the urgent information that has transmitted from the own device. If the urgent information is the urgent information transmitted from the own device, the urgent information processing unit  342  discards the urgent information. In contrast, if the urgent information is not the urgent information transmitted from the own device, the urgent information processing unit  342  decides the autonomous control that is performed in response to the urgent information. Then, the urgent information processing unit  342  outputs the information on the decided autonomous control to the control unit  360 . 
     Process Performed in the Radio Communication System  1   
     In the following, the flow of the distribution of the urgent information performed by the radio communication system  1  will be described with reference to  FIG. 9 .  FIG. 9  is a sequence diagram illustrating an example of a process performed in the radio communication system  1 . 
     First, in the vehicle  2  on which a terminal device  30 - 2  is mounted, autonomous control is operated and the urgent information is transmitted (Step S 100 ). The receiving unit  220  in the RRH  20  performs a predetermined process, such as amplification, down-conversion, or the like, on the signal received from the terminal device  30 - 2  and then outputs the processed signal to the extracting unit  231  (Step S 101 ). 
     The extracting unit  231  extracts, from among the resource blocks included in the signal output from the receiving unit  220 , the resource block (RB) allocated for transmission of the urgent information (Step S 102 ). Then, the extracting unit  231  outputs the extracted RB used for the transmission of the urgent information to the urgent information processing unit  233  (Step S 103 ). 
     Regarding each of the RBs output from the extracting unit  231 , the urgent information processing unit  233  determines whether the urgent information is included in the RB (Step S 104 ). If the urgent information is not included in any of the RBs (No at Step S 104 ), the urgent information processing unit  233  discards the data in the RB. 
     In contrast, if the urgent information is included in the RB (Yes at Step S 104 ), the urgent information processing unit  233  creates report information that includes therein the urgent information. Then, the urgent information processing unit  233  outputs the created report information to the inserting unit  232  (Step S 105 ). The inserting unit  232  inserts the report information that includes therein the urgent information created by the urgent information processing unit  233  into the RB that is previously allocated for a report of the urgent information (Step S 106 ). Then, the inserting unit  232  outputs, to the transmitting unit  221 , the signal in which the report information including the urgent information is inserted into the RB that is used to report the urgent information (Step S 107 ). The transmitting unit  221  reports, to the terminal device  30  in the cell, the signal in which the report information that includes therein the urgent information is inserted into the RB by the inserting unit  232  (Step S 108 ). 
     A terminal device  30 - 1  and the terminal device  30 - 2  monitor, in the downlink, the resource for a report of the urgent information and then acquire the urgent information reported from the RRH  20  (Steps S 109  and S 110 ). The terminal device  30 - 1  performs autonomous control on the vehicle  2  based on the acquired urgent information (Step S 111 ). In contrast, the terminal device  30 - 2  does not perform autonomous control based on the acquired urgent information because the identification information on the own device is included in the acquired urgent information, the terminal device  30 - 2  discards the subject urgent information (Step S 112 ). 
     Process Performed in the Terminal Device  30  when Urgent Information is Transmitted 
       FIG. 10  is a sequence diagram illustrating an example of a process performed in the terminal device  30  when the urgent information is transmitted 
     The sensor unit  361  detects the operation state of the vehicle  2  on which the terminal device  30  is mounted (Step S 200 ). Then, the sensor unit  361  notifies the control unit  360  of the operation information on the vehicle  2  as detection information (Step S 201 ). The control unit  360  determines, based on the detection information notified from the sensor unit  361 , whether autonomous control is performed on the vehicle  2  (Step S 202 ). If autonomous control is not performed (No at Step S 202 ), the terminal device  30  ends the process of transmitting the urgent information. 
     In contrast, if autonomous control is performed (Yes at Step S 202 ), the control unit  360  performs autonomous control on the vehicle  2  (Step S 203 ). Then, the control unit  360  outputs a notification of autonomous control to the urgent information processing unit  342  (Step S 204 ). 
     The urgent information processing unit  342  creates, based on the notification of the autonomous control output from the control unit  360 , the urgent information that includes therein the identification information on the terminal device  30  that is the transmission source (Step S 205 ). Then, the urgent information processing unit  342  outputs the created urgent information to the call control unit  340  (Step S 206 ). The call control unit  340  inserts the urgent information output from the urgent information processing unit  342  into the RB that is allocated to the own device and that is used to transmit the urgent information (Step S 207 ). The call control unit  340  outputs, to the transmitting unit  331 , the signal in which the urgent information is inserted into the predetermined RB (Step S 208 ). The transmitting unit  331  transmits the signal output from the call control unit  340  to the RRH  20  via the antenna  31  (Step S 209 ). 
     Process Performed in the Terminal Device  30  when the Urgent Information is Received 
       FIG. 11  is a sequence diagram illustrating an example of a process performed in the terminal device  30  when the urgent information is received. 
     The receiving unit  330  receives the signal output from the RRH  20  via the antenna  31 ; performs a process, such as amplification, down-conversion, and the like; and outputs the processed signal to the call control unit  340  (Step S 300 ). The call control unit  340  extracts, from among the resource blocks included in the signal received from the RRH  20 , the RB that is previously allocated for a report of the urgent information (Step S 301 ). Then, the call control unit  340  outputs, to the urgent information processing unit  342 , the extracted RB that is used to report the urgent information (Step S 302 ). 
     The urgent information processing unit  342  determines whether the urgent information is included in the RB that is output from the call control unit  340  (Step S 303 ). If the urgent information is not included (No at Step S 303 ), the urgent information processing unit  342  performs the process indicated at Step S 308 . In contrast, if the urgent information is included (Yes at Step S 303 ), the urgent information processing unit  342  refers to the identification information that is related to the terminal device  30  corresponding to the transmission source and that is included in the urgent information and then determines whether the subject urgent information is the urgent information transmitted from the own device (Step S 304 ). If the urgent information is the urgent information transmitted from the own device (Yes at Step S 304 ), the urgent information processing unit  342  discards the urgent information (Step S 305 ) and ends the process. 
     In contrast, if the urgent information is not the urgent information transmitted from the own device (No at Step S 304 ), the urgent information processing unit  342  decides autonomous control that is performed in response to the urgent information. Then, the urgent information processing unit  342  outputs the information on the decided autonomous control to the control unit  360  (Step S 306 ). The control unit  360  performs, based on the information on the autonomous control notified from the urgent information processing unit  342 , autonomous control that controls each of the units in the vehicle  2  (Step S 307 ). 
     Then, the urgent information processing unit  342  determines whether the urgent information that is not reported is present in the urgent information that has been transmitted by the own device (Step S 308 ). If the urgent information that has not been reported is not present (No at Step S 308 ), the urgent information processing unit  342  ends the process. 
     In contrast, if the urgent information that has not been reported is present (Yes at Step S 308 ), the urgent information processing unit  342  outputs, to the call control unit  340 , the urgent information that has not been reported (Step S 309 ). The call control unit  340  inserts the urgent information output from the urgent information processing unit  342  into the RB that is allocated to the own device and that is used to transmit the urgent information (Step S 310 ). The call control unit  340  outputs, to the transmitting unit  331 , the signal in which the urgent information is inserted into the predetermined RB (Step S 311 ). The transmitting unit  331  transmits the signal output from the call control unit  340  to the RRH  20  via the antenna  31  (Step S 312 ). 
     Process Performed when a Collision Occurs in Urgent Information 
       FIG. 12  is a sequence diagram illustrating an example of a process performed in the radio communication system  1  when a collision occurs in urgent information. In  FIG. 12 , it is assumed of a case in which, in the terminal devices  30 - 1  to  30 - 3  mounted on the plurality of respective vehicles  2 , the terminal device  30 - 2  and the terminal device  30 - 3  have sent the urgent information by using the same resource block. The terminal devices  30 - 1  to  30 - 3  are present in the cell in the RRH  20 . 
     First, The terminal device  30 - 2  and the terminal device  30 - 3  detect that the urgent information has been generated (Steps S 400  and S 401 ). Then, the terminal device  30 - 2  and the terminal device  30 - 3  transmit the urgent information to the RRH  20  by using the same RB that is allocated, in the uplink, for a report of the urgent information (Steps S 402  and S 403 ). A collision occurs, in the same RB, in each of the pieces of the urgent information transmitted by the respective terminal device  30 - 2  and the terminal device  30 - 3  and thus the data is destroyed. Thus, in the RRH  20 , the pieces of the urgent information transmitted from the terminal device  30 - 2  and the terminal device  30 - 3  are not properly received. Consequently, in the RB that is used to report the urgent information in the downlink, both the urgent information transmitted from the terminal device  30 - 2  and the urgent information transmitted from the terminal device  30 - 3  are not stored (Step S 404 ). 
     The terminal device  30 - 2  and the terminal device  30 - 3  detect that transmission of the urgent information has failed by referring to the RB used for the report of the urgent information in the downlink and by detecting that the urgent information transmitted from the own device is not reported (Steps S 405  and S 406 ). Each of the terminal device  30 - 2  and the terminal device  30 - 3  retransmits the urgent information after elapse of random time since the transmission of the urgent information. 
     For example, the terminal device  30 - 3  retransmits, in the uplink, the urgent information by using the RB allocated for the report of the urgent information after elapse of random time Δt 1  since the transmission of the urgent information performed at Step S 402  (Step S 407 ). The RRH  20  detects the urgent information transmitted from the terminal device  30 - 3  (Step S 408 ). Then, the RRH  20  reloads the detected urgent information to the RB used for the report of the urgent information in the downlink and then reports to the terminal devices  30 - 1  to  30 - 3  located in the cell (Step S 409 ). 
     The terminal devices  30 - 1  to  30 - 3  refer to the RB used for the report of the urgent information in the downlink and acquire the urgent information (Steps S 410 , S 411 , and S 412 ). The terminal devices  30 - 1  and  30 - 2  detect that the reported urgent information is not the urgent information transmitted from the respective own devices and perform autonomous control on the respective vehicles  2  based on the urgent information (Steps S 413  and S 414 ). In contrast, the terminal device  30 - 3  detects that the reported urgent information is the urgent information transmitted from the own device and discards the acquired urgent information (Step S 415 ). 
     Furthermore, for example, the terminal device  30 - 2  retransmits the urgent information by using the RB that is allocated for the report of the urgent information in the uplink after elapse of random time Δt 2  since the transmission of the urgent information performed at Step S 403  (Step S 416 ). The RRH  20  detects the urgent information transmitted from the terminal device  30 - 2  (Step S 417 ). Then, the RRH  20  reloads the detected urgent information to the RB used for reporting the urgent information in the downlink and reports to the terminal devices  30 - 1  to  30 - 3  in the cell (Step S 418 ). 
     The terminal devices  30 - 1  to  30 - 3  refer to the RB used for the report of the urgent information in the downlink and then acquire the urgent information (Steps S 419 , S 420 , and S 421 ). The terminal devices  30 - 1  and  30 - 3  detect that the detected urgent information is not the urgent information transmitted from the own device and perform autonomous control on each of the vehicles  2  based on the urgent information (Steps S 422  and S 423 ). In contrast, the terminal device  30 - 2  detects that the reported urgent information is the urgent information transmitted from the device and discards the acquired urgent information (Step S 424 ). 
     Hardware 
       FIG. 13  is a schematic diagram illustrating an example of hardware of the BBU  10 . The BBU  10  includes, for example, as illustrated in  FIG. 13 , a RRH interface circuit  100 , a network interface circuit  101 , a central processing unit (CPU)  102 , a digital signal processor (DSP)  103 , and a memory  104 . 
     The CPU  102  and the DSP  103  are connected to the RRH interface circuit  100 , the network interface circuit  101 , and the memory  104  via a bus. The RRH interface circuit  100  implements the function of, for example, the RRH interface unit  11  illustrated in  FIG. 2 . Furthermore, the network interface circuit  101  implements the function of, for example, the network interface unit  13  illustrated in  FIG. 2 . 
     The memory  104  stores therein programs for implementing the function of, for example, the communication control unit  12  illustrated in  FIG. 2 . By reading the programs stored in the memory  104  from the memory  104  and executing the read programs, the CPU  102  cooperates with the DSP  103  and implements the function of, for example, the communication control unit  12  illustrated in  FIG. 2 , i.e., the function of the call control unit  120  and the protocol management unit  121 . 
       FIG. 14  is a schematic diagram illustrating an example of hardware of the RRH  20 . The RRH  20  includes, for example, as illustrated in  FIG. 14 , an RF circuit  200 , a BBU interface circuit  201 , a CPU  202 , a DSP  203 , a memory  204 , and the antenna  21 . 
     The CPU  202  and the DSP  203  are connected to the RF circuit  200 , the BBU interface circuit  201 , and the memory  204  via a bus. The RF circuit  200  implements the function of, for example, the radio processing unit  22  illustrated in  FIG. 3 . Furthermore, the BBU interface circuit  201  implements the function of, for example, the BBU interface unit  24  illustrated in  FIG. 3 . 
     The memory  204  stores therein programs for implementing the function of, for example, the communication control unit  23  illustrated in  FIG. 3 . By reading the programs stored in the memory  204  from the memory  204  and executing the read programs, the CPU  202  cooperates with the memory  204  and implements the function of, for example, the communication control unit  23  illustrated in  FIG. 3 , i.e., the function of the extracting unit  231 , the inserting unit  232 , and the urgent information processing unit  233 . 
       FIG. 15  is a schematic diagram illustrating an example of hardware of the terminal device  30 . The terminal device  30  includes, for example, as illustrated in  FIG. 15 , a communication device  300 , a vehicle body control device  305 , and the antenna  31 . The communication device  300  implements, for example, the function of the communication management unit  32  illustrated in  FIG. 8 . Furthermore, the vehicle body control device  305  implements the function of, for example, the vehicle body control unit  36  illustrated in  FIG. 8 . 
     The communication device  300  includes, for example, as illustrated in  FIG. 15 , an RF circuit  301 , a user interface circuit  302 , a CPU  303 , and a memory  304 . The RF circuit  301  implements the function of, for example, the radio processing unit  33  illustrated in  FIG. 8 , i.e., the function of the receiving unit  330  and the transmitting unit  331 . The user interface circuit  302  is, for example, an input device, such as a touch panel, or the like or an output device, such as a liquid crystal monitor, or the like and implements the function of, for example, the user interface unit  35  illustrated in  FIG. 8 . 
     The memory  304  stores therein programs for implementing the function of, for example, the communication control unit  34  illustrated in  FIG. 8 . By reading the programs stored in the memory  304  from the memory  304 , the CPU  303  implements the function of, for example, the communication control unit  34  illustrated in  FIG. 8 , i.e., the function of the call control unit  340 , the protocol management unit  341 , and the urgent information processing unit  342 . 
     The vehicle body control device  305  includes, for example, as illustrated in  FIG. 15 , a sensor  306 , a vehicle body interface circuit  307 , a CPU  308 , and a memory  309 . The sensor  306  includes, for example, a velocity sensor, a distance sensor, a GPS sensor, or the like. The sensor  306  implements, for example, the function of the sensor unit  361  illustrated in  FIG. 8 . The vehicle body interface circuit  307  is an interface for connecting each of the unit in the vehicle  2  to the CPU  308 . 
     The memory  309  stores therein programs for implementing the function of, for example, the control unit  360  illustrated in  FIG. 8 . By reading the programs stored in the memory  309  from the memory  309 , the CPU  308  implements the function of, for example, the control unit  360  illustrated in  FIG. 8 . 
     Effect of the Embodiment 
     As described above, the RRH  20  according to the embodiment includes the extracting unit  231 , the urgent information processing unit  233 , and the inserting unit  232 . The extracting unit  231  extracts, from among the resource blocks included in the signal received from the terminal device  30 , the resource block that is previously allocated for transmission of urgent information. The urgent information processing unit  233  determines whether the urgent information is included in the resource block extracted by the extracting unit  231 . If the urgent information is included in the resource block extracted by the extracting unit  231 , the urgent information processing unit  233  creates report information that includes therein the urgent information included in the resource block extracted by the extracting unit  231 . The inserting unit  232  inserts the report information that includes therein the urgent information and that is created by the urgent information processing unit  233  into the resource block that is previously allocated for the transmission of the urgent information. Consequently, the RRH  20  can convey the information that has high urgency and that has been sent from the certain terminal device  30  to the other terminal device  30  in a low delay. 
     For example, if the vehicle  2  is traveling at 40 km per hour, the vehicle  2  moves forward about 11 m per second. Thus, the distance between before and after the plurality of the vehicles  2  traveling at 40 km per hour is, for example, 3 to 5 m, the reaction velocity equal to or less than 500 ms is needed to avoid a collision due to autonomous control. If the terminal device  30  mounted on the vehicle  2  performs communication with the data server  5  via the communication network  4 , such as the Internet, or the like, in general, it is conceivable that a response is sent back in the order close to in units of seconds. Furthermore, if congestion occurs in the communication network  4 , the delay time thereof varies and it is difficult to guarantee a response in a short period. Thus, if information is reported via the data server  5 , it is difficult to avoid the collision due to the autonomous control under the condition described above. 
     Furthermore, regarding the autonomous control performed based on the operation detection of the sensor mounted on the vehicle  2 , it is conceivable that time is needed in the order of 100 milliseconds. Here, with the radio communication system  1  according to the embodiment, the transmission period of the report information between the radio sections is performed in units of subframes (for example, in units of 1 millisecond). Thus, even if the time period of the process of reloading the signal performed by the RRH  20  is added, the RRH  20  can report the information to the other terminal devices  30  in the order of several tens of milliseconds. Consequently, even if the processing time that is in the order of 100 milliseconds due to the autonomous control described above is added to the transmission period of the report information in the radio communication system  1  according to the embodiment, the processing time is sufficiently within the reaction velocity described above. Furthermore, because the urgent information is turned back at the RRH  20 , a delay factor due to congestion or the like in the communication network  4  is not present and fluctuation of delay time is not also present, whereby it is possible to securely report the information in a short period of time and it is possible to implement highly reliable automated operation. 
     Furthermore, in the embodiment described above, a plurality of resource blocks each having a different frequency band is allocated, in the same time zone, for the transmission of the urgent information sent from the terminal device  30 . Furthermore, a plurality of the resource blocks each having a different frequency band is previously allocated, in the same time zone, for a report of the urgent information. Consequently, it is possible to prevent a collision of the urgent information transmitted by the plurality of the terminal devices  30  in a short period of time. 
     Furthermore, in the embodiment described above, if the urgent information is included in the resource block that is extracted by the extracting unit  231 , the inserting unit  232  inserts the report information that includes therein the urgent information included in the resource block extracted by the extracting unit  231  into the resource block used for a report that is reported first. Consequently, the RRH  20  can convey the information that has high urgency and that is transmitted from the certain terminal device  30  by using the other terminal device  30  in a low delay. 
     Furthermore, in the embodiment described above, a plurality of resource blocks is allocated, in each of the subframes, for each combination of the time zone and the frequency band, in order to use for transmission of the urgent information received from the terminal device  30 . Furthermore, the BBU  10  allocates, in each of the subframes, the resource block that is used for transmission of the urgent information and that is allocated to each of the terminal devices  30  located within the range of the RRH  20  to each of the terminal devices  30  such that the number of terminal devices  30  that uses the same resource block becomes small. Consequently, it is possible to prevent a collision of the urgent information transmitted in a short time period by the plurality of the terminal devices  30 . 
     Others 
     The technology disclosed in the present application is not limited to the embodiments described above and various modifications are possible as long as they do not depart from the spirit of the present application. 
     For example, in the embodiment described above, information used for autonomous control of the vehicle  2  has been described as the urgent information; however, the disclosed technology is not limited to this. For example, the information is not used for autonomous control of the vehicle  2  as long as the information is used, based on the information transmitted from the certain terminal device  30 , by the other terminal device  30  for a system that performs a process in a short period of time. 
     Furthermore, in the embodiment described above, the RRH  20  turns back the urgent information transmitted from the terminal device  30 , whereby the information is conveyed to the plurality of the terminal devices  30  in the cell in the RRH  20  in a short period of time; however, the disclosed technology is not limited to this. For example, in addition to turning back the urgent information transmitted from the terminal device  30  at the RRH  20 , the subject information may also be transferred to the other RRH  20  via the BBU  10 . Consequently, the urgent information transmitted from the terminal device  30  that is located in the cell in the certain RRH  20  is also conveyed to the terminal device  30  located in the cell in the other RRH  20 . Consequently, it is possible to convey the urgent information transmitted from the certain terminal device  30  to the terminal device  30  located in a wider area. 
     Furthermore, in the embodiment described above, the execution of autonomous control performed by the vehicle  2  has been described as an example of a trigger for the generation of the urgent information; however, the disclosed technology is not limited to this. In addition to the execution of autonomous control, for example, the urgent information may also be transmitted to the base station  6  by the terminal device  30  in each of the vehicles  2  as a trigger when the sensor  306  detects an excessive brake operation performed by humans. 
     Furthermore, for example, in addition to turning the urgent information transmitted from the terminal device  30  back at the RRH  20 , it may also be possible to transfer, via the data server  5 , the subject urgent information to each of the RRHs  20  connected to the other BBU  10  and convey the subject urgent information to the terminal devices  30  located in the cell in each of the RRHs  20 . Consequently, the urgent information transmitted from the terminal device  30  is also conveyed to the other terminal device  30  that is away from the subject terminal device  30 . In the terminal device  30  located away from the terminal device  30  that is the transmission source of the urgent information, there is little need to perform control based on the urgent information in a short period of time. However, this type of terminal device  30  can efficiently use the conveyed urgent information for the movement of the vehicle  2  in accordance with the content of the urgent information, such as selecting an alternate routing of the location of the generation of the urgent information. 
     Furthermore, in the embodiment described above, the BBU  10  allocates the resource block for transmission of the urgent information in the uplink to each of the terminal devices  30  located in the cell in the RRH  20 ; however, the disclosed technology is not limited to this. For example, each of the terminal devices  30  may also randomly select, based on the identification information or the like allocated to the own device, the resource block that is used by the own device to transmit the urgent information from among the resource blocks used for the transmission of the urgent information in the uplink. Consequently, the processing load of the BBU  10  can be reduced. 
     According to an aspect of an embodiment of the radio device, the base station, and the terminal device disclosed in the present application, it is possible to transmit information having high urgency and being transmitted from a certain terminal device to another terminal device in a low delay. 
     All examples and conditional language recited herein are intended for 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 the embodiment of the present invention has 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.