Patent Publication Number: US-2023146213-A1

Title: Communication device and communication method

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to a communication device and a communication method. 
     2. Description of the Background Art 
     In recent years, various systems have been developed for preventing collision that can occur between vehicles or between a vehicle and a pedestrian beforehand or reducing impact at the time of collision. In such systems, it is important to accurately and immediately detect an object as an obstacle to traveling of an own vehicle, such as another vehicle or a pedestrian present around the own vehicle. As detection means for obstacles, a camera, a radar sensor, and the like are provided to the vehicle, and an obstacle that might hamper traveling of the own vehicle is detected using image information, radar information, and the like. 
     However, due to a factor such as a sensor detection area or a blind spot from the own vehicle, there is limitation in obstacle detection by the own vehicle alone. Therefore, technology for mutually acquiring and sharing obstacle information from other vehicles, roadside devices, and the like using vehicle-to-vehicle communication, road-to-vehicle communication, and the like, is being considered. 
     In such a system for sharing obstacle information, own detected obstacle information is mutually transmitted/received to/from another vehicle having a communication device and traveling near the own vehicle, a roadside device provided on a roadside, and the like. Therefore, a wide communication band is needed at a place such as an intersection having a large traffic volume. 
     In a road condition detection system described in Patent Document 1, in order to solve the above problem, at the time of transmitting obstacle information to another vehicle or a roadside device, information about the obstacle detection area of the other vehicle or the roadside device is received, and information obtained by removing information about obstacles in the same detection area is transmitted to the other vehicle, the roadside device, or the like, whereby the whole transmission amount is reduced.
     Patent Document 1: Japanese Patent No. 4345832   

     In the road condition detection system described in Patent Document 1, when sharing obstacle information with another vehicle or a roadside device around the own vehicle, it is necessary to mutually communicate not only the detected obstacle information but also information of the obstacle detection area by separately using a dedicated communication message. Therefore, at a place such as an intersection having a large traffic volume, the communication message amount increases, leading to communication congestion. 
     SUMMARY OF THE INVENTION 
     The present disclosure has been made to solve the above problem, and an object of the present disclosure is to provide a communication device and a communication method that enable efficient communication. 
     A communication device according to one aspect of the present disclosure includes: a wireless receiving unit for receiving wireless information including first obstacle information of a first obstacle which is at least one obstacle, from outside; a first obstacle extraction unit for extracting the first obstacle information from the wireless information; a second obstacle detection unit for detecting second obstacle information of a second obstacle which is at least one obstacle present in an own surrounding area by a sensor; and an overlap information removing unit which, if there is overlap obstacle information between the first obstacle information and the second obstacle information, removes the overlap obstacle information from the second obstacle information, to generate difference obstacle information. 
     A communication method according to another aspect of the present disclosure includes: a wireless receiving step of receiving wireless information including first obstacle information of a first obstacle which is at least, one obstacle, from outside; a first obstacle extraction step of extracting the first obstacle information from the wireless information; a second obstacle detection step of detecting second obstacle information of a second obstacle which is at least one obstacle present in an own surrounding area by a sensor; and an overlap information removing step of, if there is overlap obstacle information between the first obstacle information and the second obstacle information, removing the overlap obstacle information from the second obstacle information, to generate difference obstacle information. 
     In the communication device and the communication method according to the present disclosure, information overlapping with first obstacle information transmitted from another communication device is removed from second obstacle information detected by the own communication device, to generate difference obstacle information, and the difference obstacle information is transmitted to be shared with communication devices of other vehicles and the like. Thus, effects of enabling reduction in the data communication amount and enabling efficient communication are provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram showing an example in which a communication device according to the first embodiment of the present disclosure is used; 
         FIG.  2    is a schematic diagram of a vehicle provided with the communication device according to the first embodiment; 
         FIG.  3    is a function block diagram showing the configuration of the communication device according to the first embodiment; 
         FIG.  4    is a flowchart illustrating a communication method according to the first embodiment; 
         FIG.  5    is a function block diagram showing the configuration of a communication device according to the second embodiment of the present disclosure; 
         FIG.  6    is a flowchart illustrating a communication method according to the second embodiment; 
         FIG.  7    is a function block diagram showing the configuration of a communication device according to the third embodiment of the present disclosure; 
         FIG.  8    is a flowchart illustrating a communication method according to the third embodiment; 
         FIG.  9    is a diagram showing a hardware configuration for implementing the communication device according to each of the first to third embodiments; and 
         FIG.  10    is a diagram showing a hardware configuration for implementing the communication device according to each of the first to third embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
     Hereinafter, to describe the present disclosure in more detail, embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the drawings for illustrating the embodiments of the present disclosure, components having the same function are denoted by the same reference character and description thereof will not be repeated. 
     First Embodiment 
       FIG.  1    is a schematic diagram snowing an example in which a communication device  100  according to the first embodiment is used. At an intersection in  FIG.  1   , a roadside device  1  including a roadside sensor  1   a  and a communication. unit  1   b  is provided, and detects an obstacle such as a pedestrian or a vehicle in a detection area  2  of the roadside sensor and transmits information about the obstacle, i.e., the kind, position, speed, orientation, detection accuracy, and the like about the obstacle, via wireless communication. Here, an obstacle as a transmission target by the roadside device  1  may be referred to as a first obstacle and information about the obstacle transmitted by the roadside device  1  may be referred to as first obstacle information. 
     Examples of the roadside sensor  1   a  provided to the roadside device  1  include a millimeter-wave radar, an image sensor, and a camera. The roadside sensor  1   a  detects, as first obstacle information, information such as the kind of a vehicle traveling on a road such as an intersection, the vehicle position, the vehicle speed, the vehicle advancing direction, and detection accuracy. In addition, the roadside sensor  1   a  similarly detects, as first obstacle information, information such as a pedestrian walking on a road, i.e., the pedestrian position, the pedestrian walking speed, the pedestrian walking direction, and detection accuracy. 
     Various kinds of information detected by the roadside sensor  1   a  are wirelessly transmitted as wireless information by the communication unit  1   b  in the roadside device  1  to a vehicle traveling near the roadside device  1 , and the like. Such various kinds of information detected by the roadside sensor  1   a  include first obstacle information. 
     As shown in a vehicle schematic diagram in  FIG.  2   , as in the roadside device  1 , an own vehicle  3  is provided with an on-vehicle sensor  40  and the communication device  100  according to the first embodiment. In a detection area  4  of the on-vehicle sensor, an obstacle such as a pedestrian or another vehicle  5  is detected by the on-vehicle sensor  40 . An obstacle as a detection target by the on-vehicle sensor  40  may be referred to as a second obstacle. In addition, information of the detected obstacle around the own vehicle  3  may be referred to as second obstacle information. 
     The communication device  100  transmits second obstacle information to the roadside device  1 , the other vehicle  5  traveling near the own vehicle  3 , and the like, via wireless communication, under a certain condition. 
     Configuration of Communication Device According to First Embodiment 
       FIG.  3    is a function block diagram showing the configuration of the communication device  100  according to the first embodiment, provided to the vehicle. The communication device  100  according so the first embodiment includes a second obstacle detection unit  101 , an overlap information removing unit  102 , a wireless transmission unit  103 , a first obstacle extraction unit  104 , and a wireless receiving unit  10 ′). 
     The wireless receiving unit  105  receives information transmitted from communication devices provided to the roadside device  1 , the other vehicle  5 , and the like. 
     The second obstacle detection unit  101  detects obstacles present around the own vehicle  3  by the on-vehicle sensor  40 . The on-vehicle sensor  40  may be, for example, a radar sensor. As shown in  FIG.  2   , the radar sensor is generally provided on the front side of the own vehicle  3  so that an area frontward of the own vehicle  3  can be detected. The radar sensor radiates radio waves frontward of the own vehicle  3  and detects a reflected wave based on the radiated radio waves, thereby detecting a second obstacle present around the own vehicle  3 . 
     As the on-vehicle sensor  40 , an image sensor may be used. On the basis of image information acquired by the image sensor provided on the front side of the own vehicle  3 , the second obstacle detection unit  101  detects information of a second obstacle present around the own vehicle  3 , such as the position, speed, and shape of the second obstacle. Further, if the image sensor is provided also on the lateral sides and the rear side in addition to the front side, the second obstacle detection unit  101  can also detect a second obstacle present therearound on the lateral sides and the rear side. Alternatively, the on-vehicle sensor  40  may be an ultrasonic sensor. 
     The first obstacle extraction unit  104  extracts first obstacle information detected by a sensor provided to a transmission source device, from wireless information received by the wireless receiving unit  105 . An example of the transmission source device is the roadside device  1  which is provided with the roadside sensor  1   a  and wirelessly transmits obstacle information detected by the roadside sensor  1   a,  i.e., first obstacle information, to the outside via the communication unit  1   b.    
     The overlap information removing unit  102  removes information of an overlap obstacle included in first obstacles extracted by the first obstacle extraction unit  104 , from among second obstacles detected by the second obstacle detection unit  101 , to generate difference obstacle information. 
     The wireless transmission unit  103  transmits the difference obstacle information generated by the overlap information removing unit  102 , to communication devices provided to the roadside device  1 , the other vehicle  5 , and the like present outside the communication device  100  according to the first embodiment. 
     Communication Method According to First Embodiment 
     A communication method according to the first embodiment will be described with reference to a flowchart in  FIG.  4   . The flowchart in  FIG.  4    is regularly started per wireless transmission cycle, e.g., 100 ms. 
     In step S 101 , the wireless receiving unit  105  of the communication device  100  provided to the own vehicle  3  receives wireless information transmitted from the communication unit  1   b  of the roadside device  1 . 
     In step S 102 , the communication device  100  extracts first obstacle information detected by the roadside sensor  1   a  of the roadside device  1  from the wireless information received from the roadside device  1 . 
     In step S 103 , whether or not first obstacle information detected by the roadside sensor  1   a  of the roadside device  1  has been successfully extracted in step S 102 , i.e., whether or not first obstacle information is present in the wireless information, is determined. If first obstacle information is present in the wireless information and thus has been successfully detected, i.e., in a case of YES in step S 103 , the process proceeds to step S 104 . On the other hand, if first obstacle information is not present in the wireless information and thus has not been detected, i.e., in a case of NO in step S 103 , the process is ended. 
     In step S 104 , the communication device  100  acquires second obstacle information about a second obstacle detected by the on-vehicle sensor  40 . 
     In step S 105 , the communication device  100  removes, from the second obstacle information acquired in step S 104 , obstacle information included in the first obstacle information extracted in step S 102 , i.e., overlap obstacle information, to generate difference obstacle information. 
     As an example of a method for identifying each obstacle, processing may be performed such that, if differences in the positions, speeds, orientations, and the like of detected obstacles fall within a predetermined range, such obstacles are determined as an identical obstacle. However, this processing method is merely an example and the identifying method is not limited thereto. 
     In step S 106 , whether or not there is difference obstacle information generated in step S 105  is determined The reason is that there can be a case where the second obstacle information detected by the on-vehicle sensor  40  provided to the own vehicle  3  completely coincides with she first obstacle information detected by the roadside sensor  1   a  of the roadside device  1 , and in this case, there is no difference obstacle information. 
     If there is difference obstacle information generated in step S 105 , i.e., in a case of YES in step S 106 , step S 107  is performed. On the other hand, if there is no difference obstacle information, i.e., in a case of NO in step S 106 , the process is ended. 
     In step S 107 , the communication device  100  wirelessly transmits the difference obstacle information generated in step S 105 , to the roadside device  1  outside the communication device  100 , the other vehicle  5  in the intersection, and the like. 
     In the above description, the communication method according to the first embodiment has been described. 
     An example of the communication method according to the first embodiment will be shown below. It is assumed that first obstacle information detected by the roadside sensor  1   a  of the roadside device  1  is represented by the following set S 1 . 
     S 1 ={a 1 , a 2 , a 3 , a 4 , a 5 , a 6 , a 7 , a 8 , a 9 , . . . } 
     Here a 1 , a 2 , a 3 , . . . are information of individual obstacles on a road, detected by the roadside sensor  1   a.    
     Meanwhile, it is assumed that second obstacle information which is information of obstacles present around the own vehicle  3 , detected by the on-vehicle sensor  40  provided to the own vehicle  3 , is represented by the following set S 2 . 
     S 2 ={b 1 , b 2 , b 3 , b 4 , b 5 , b 6 , b 7 , b 8 , b 9 , . . . } 
     Here, b 1 , b 2 , b 3 , . . . are information of individual obstacles present around the own vehicle  3 , detected by the on-vehicle sensor  40 . 
     Then, it is assumed that, between respective obstacle information pieces of the first obstacle information Si and the second obstacle information S 2 , the following information pieces coincide with each other. 
     a 2 =b 2 , a 4 =b 4 , a 6 =b 6 , a 9 =b 9 , . . . 
     That is, in the second obstacle information S 2 , there are b 2 , b 4 , b 6 , b 9 , . . . which are overlap obstacle information between the first obstacle information S 1  and the second obstacle information S 2 . 
     For identifying obstacles in the first obstacle information S 1  and the second obstacle information S 2 , as described above, processing may be performed such that, if differences in the positions, speeds, orientations, and the like of detected obstacles fall within a predetermined range, such obstacles are determined as an identical obstacle. 
     That is, if differences between the position, speed, and orientation of the obstacle a 2  which is one element of the first obstacle information S 1  and the position, speed, and orientation of the obstacle b 2  which is one element of the second obstacle information S 2  each fall within a predetermined range, the obstacle a 2  which is one element of the first obstacle information S 1  and the obstacle b 2  which is one element of the second obstacle information S 2  can be determined as identical obstacle information, i.e., overlap obstacle information. 
     By removing the obstacle information overlapping with the first obstacle information S 1  from the second obstacle information S 2,  the following difference obstacle information S d  is generated. 
     S d ={b 1 , b 3 , b 5 , b 7 , b 8 , . . . } 
     The difference obstacle information S d  is wirelessly transmitted to the outside of the own vehicle  3  from the wireless transmission unit  103  of the communication device  100  provided to the own vehicle  3 . 
     A case where another vehicle  5   a  traveling at the intersection shown in  FIG.  1    receives obstacle information will be described below. The other vehicle  5   a  is located in the detection area  2  of the roadside sensor of the roadside device  1  and at the same time, is located also in the detection area  4  of the on-vehicle sensor of the own vehicle 
     Therefore, information a t1  about the other vehicle  5   a  detected as an obstacle is included in the first obstacle information S 1  detected by the roadside sensor  1   a  of the roadside device  1 . In addition, information b t1  about the other vehicle  5   a  detected as an obstacle is included in the second obstacle information S 2  detected by the on-vehicle sensor  40  of the own vehicle  3 . The information a t1  and the information b t1  are information based on the other vehicle  5   a  that is the identical obstacle. Therefore, when the own vehicle  3  wirelessly transmits the second obstacle information S 2  to the outside via the wireless transmission unit  103 , the difference obstacle information obtained by removing the information b t1  which is the overlap information about the other vehicle  5   a  is wirelessly transmitted, and thus efficient communication can be achieved. 
     Next, a case where the other vehicle  5   a  receives obstacle information from the outside will be described below. As described above, the other vehicle  5   a  is located in an area where wireless information can be received from both of the roadside device  1  and the communication device  100  provided to the own vehicle  3 . 
     Supposing that the own vehicle  3  only has a function of merely transmitting information (second obstacle information) of an obstacle around the own vehicle  3  detected by the on-vehicle sensor  40 , in the above example, the other vehicle  5   a  receives combined obstacle information S s  obtained by merely combining the first obstacle information S 1  transmitted from the roadside device  1  and the second obstacle information S 2  transmitted from the own vehicle  3 . That is, the other vehicle  5   a  receives the following information. 
     S s =S 1 +S 2 ={a 1 , a 2 , a 3 , . . . , b 1 , b 2 , b 3 , . . . } 
     However, since overlap obstacle information is included in the combined obstacle information S s , the data communication amount increases, leading to communication congestion. 
     On the other hand, in a case where the own vehicle  3  is provided with the communication device  100  according to the first embodiment, corrected combined obstacle information S, obtained by combining the first obstacle information S 1  transmitted from the roadside device  1  and the difference obstacle information S d  transmitted from the own vehicle  3  no the other vehicle  5   a  is such information that overlap obstacle information therebetween has been removed, and therefore, in the above example, this information is represented as follows. 
     S u =S 1 +S d ={a 1 , a 2 , a 3 , . . . , b 1 , b 3 , b 5 , b 7 , b 8 , . . . } 
     That is, the other vehicle  5   a  receives the corrected combined obstacle information S u  that does not include overlap obstacle information at all. Thus, efficient communication not including unnecessary overlap information can be achieved. 
     Effects of First Embodiment 
     As described above, in the communication device  100  and the communication method according to the first embodiment, obstacle information overlapping with first obstacle information transmitted from another communication device, e.g., the roadside device  1 , is removed from second obstacle information detected by the on-vehicle sensor  40  of the own vehicle  3 , to generate difference obstacle information, and the difference obstacle information is transmitted to be shared with the communication device of another vehicle, and the like. Thus, it becomes possible to reduce the data communication amount, and in addition, since a communication message need not be separately transmitted, an effect of enabling efficient communication is also provided. 
     Second Embodiment 
       FIG.  5    is a function block diagram showing the configuration of a communication device  200  according to the second embodiment of the present disclosure. The communication device  200  shown in  FIG.  5    further includes a detection area estimation unit  201  in addition to the configuration of the communication device  100  according to the first embodiment. For the same components as those in the communication device  100  according to the first embodiment, description is omitted. 
     On the basis of first obstacle information extracted by the first obstacle extraction unit  104  from wireless information transmitted from another communication device, the detection area estimation unit  201  estimates a first obstacle detection area which is an area where the first obstacle has been detected by a sensor provided to the other communication device. As an example, in a case where the other communication device is the roadside device  1 , a detection area where the first obstacle has been detected by the roadside sensor  1   a  provided to the roadside device  1  is estimated as the first obstacle detection area. 
     Communication Method According to Second Embodiment 
     With reference to a flowchart in  FIG.  6   , a communication method according to the second embodiment will be described. It is noted that operations in steps S 201  to S 203  in the flowchart in  FIG.  6    are respectively the same as those in steps S 101  to S 103  in the flowchart in  FIG.  4    of the first embodiment, and operations in steps S 205 , S 207 , and S 208  in the flowchart in  FIG.  6    are respectively the same as those in steps S 104 , S 106 , and S 107  in the flowchart in  FIG.  4   , and therefore description thereof is omitted. 
     In step S 204 , on the basis of the first obstacle information extracted by the first obstacle extraction unit  104  from the wireless information transmitted from the other communication device, the detection area estimation unit  201  estimates the first obstacle detection area which is an area where the first obstacle has been detected by the sensor provided to the other communication device. 
     As an example of a method for estimating the first obstacle detection area by the detection area estimation unit  201 , processing may be performed such that the maximum and minimum latitudes and longitudes are calculated from position information of all the target obstacles and a rectangular area specified by the latitudes and the longitudes is estimated as the sensor detection area. However, this processing method is merely an example and the estimation method is not limited thereto. 
     In step S 206 , if there is an overlap detection area between the above first obstacle detection area and a second obstacle detection area which is an area where the second obstacle included in the second obstacle information has been detected, the overlap information removing unit  102  removes, as overlap obstacle information, obstacle information included in the overlap detection area, from the second obstacle information, to generate difference obstacle information. 
     In the above description, the communication method according to the second embodiment has been described. 
     In the above processing by the overlap information removing unit  102  in which obstacle information overlapping with the first obstacle information is removed from the second obstacle information, sameness between obstacle detection areas is used as a reference for determining overlap between obstacles included in both of the first obstacle information and the second obstacle information. Thus, it becomes possible to perform processing more simply and faster than determination based on differences in the positions, speeds, orientations, and the like of the detected obstacles. 
     Effects of Second Embodiment 
     As described above, in the communication device  200  and the communication method according to the second embodiment, obstacle information detected in an area overlapping with the first obstacle information of the roadside device  1  is removed from the second obstacle information detected by the on-vehicle sensor  40  of the own vehicle  3 , to generate difference obstacle information. Thus, in addition to the effect of reducing the data communication amount, since the first obstacle detection area is estimated on the basis of the first obstacle information, a communication message need not be separately transmitted, and therefore an effect that the overlap obstacle information removing process can be performed more simply and faster is also provided. 
     Third Embodiment 
       FIG.  7    is a function block diagram showing the configuration of a communication device  300  according to the third embodiment. The communication device  300  shown in  FIG.  7    further includes a detection accuracy extraction unit  301  in addition to the configuration of the communication device  100  according to the first embodiment. Description of the same components as those in the communication device  100  according to the first embodiment is omitted. 
     The detection accuracy extraction unit  301  extracts, from first obstacle information extracted by the first obstacle extraction unit  104  from wireless information transmitted from another communication device, first obstacle detection accuracy which is detection accuracy when the first obstacle has been detected by a sensor provided to the other communication device. As an example, in a case where the other communication device is the roadside device  1 , detection accuracy when the roadside sensor  1   a  provided to the roadside device  1  has detected the first obstacle is extracted as the first obstacle detection accuracy. 
     Communication Method According to Third Embodiment 
     With reference to a flowchart in  FIG.  8   , a communication method according to the third embodiment will be described. It is noted that operations in steps S 301  to S 303  in the flowchart in  FIG.  8    are respectively the same as those in steps S 101  to S 103  in the flowchart in  FIG.  4    of the first embodiment, and operations in steps S 307  and S 308  in the flowchart in  FIG.  8    are respectively the same as those in steps S 106  and S 107  in the flowchart in  FIG.  4   , and therefore description thereof is omitted. 
     In step S 304 , the detection accuracy extraction unit  301  extracts first obstacle detection accuracy when the first obstacle has been detected, from the first obstacle information extracted by the first obstacle extraction unit  104  from the wireless information transmitted from the other communication device. 
     In step S 305 , the second obstacle detection unit  101  acquires the second obstacle information detected by the on-vehicle sensor  40  of the own vehicle  3 . In the second obstacle information, information of second obstacle detection accuracy when the on-vehicle sensor  40  detects the second obstacle is included. 
     In step S 306 , if there is overlap obstacle information between the second obstacle information and the first obstacle information, and in the overlap obstacle information, the second obstacle detection accuracy is lower than the first obstacle detection accuracy, the overlap information removing unit  102  removes, as overlap obstacle information, the obstacle information having lower detection accuracy, from the second obstacle information, to generate difference obstacle information. 
     In the above description, the communication method according to the third embodiment has been described. 
     In the above processing by the overlap information removing unit  102  in which the obstacle information overlapping with the first obstacle information is removed from the second obstacle information, the obstacle information having higher detection accuracy is kept, thus providing an effect chat the obstacle information having higher detection accuracy can be shared with other communication devices. 
     Effects of Third Embodiment 
     As described above, in de communication device  300  and the communication method according to the third embodiment, if, in overlap obstacle information between second obstacle information detected by the on-vehicle sensor  40  of the own vehicle  3  and first obstacle information transmitted from another communication device, e.g., the roadside device  1 , the second obstacle detection accuracy is lower than the first obstacle detection accuracy, the overlap obstacle information is removed from the second obstacle information, to generate difference obstacle information. Thus, in addition to the effect of reducing the data communication amount, an effect that obstacle information having high detection accuracy can be shared with other communication devices is also provided. 
     In the above embodiments, the configuration in which the communication device  100 ,  200 ,  300  according so each embodiment is provided to a vehicle as shown in  FIG.  2    has been described as an example. However, the communication device  100 ,  200 ,  300  according to each embodiment may not necessarily be provided to a vehicle, and for example, may be provided in the roadside device  1  shown in  FIG.  1   . 
     The present disclosure is not limited to the above embodiments and various modifications may be made within the gist of the present disclosure. For example, the present disclosure is applicable to not only a communication device provided to a vehicle but also a pedestrian&#39;s communication device having a similar function (pedestrian-to-vehicle communication or pedestrian-to-roadside communication). 
     In the above description, the configuration in which the functions of components of the communication devices  100 ,  200 ,  300  according to the first to third embodiments are implemented by one of hardware and software, etc., has been described. However, without limitation thereto, some of the components of the communication devices  100 ,  200 ,  300  according to the first to third embodiments may be implemented by dedicated hardware, and the other components may be implemented by software, etc. 
     For example, as shown in  FIG.  9    and  FIG.  10   , for some components, the functions thereof may be implemented by a processing circuit  50  as dedicated hardware, and for the other components, the processing circuit  50  as the processor  51  may read and execute a program, stored in a memory  52 , for causing a computer or the like to execute the communication control method according to the first to third embodiments, thereby implementing the functions of the other components. 
     Further, as shown in  FIG.  10   , setting data to be used in the function units and the like of the communication devices  100 ,  200 ,  300  according to the first to third embodiments may be installed as a part of software to the memory  52  from a storage medium  53  storing a program  54  for causing a computer or the like to execute the communication control method according to the first to third embodiments. 
     As described above, the communication devices  100 ,  200 ,  300  according to the first to third embodiments can implement the above-described functions by hardware, software, etc., or a combination thereof. 
     Although the disclosure is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects, and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations to one or more of the embodiments of the disclosure. 
     It is therefore understood that numerous modifications which have not been exemplified can be devised without departing from the scope of the present disclosure. For example, at least one of the constituent components may be modified, added, or eliminated. At least one of the constituent components mentioned in at least one of the preferred embodiments may be selected and combined with the constituent components mentioned in another preferred embodiment. 
     DESCRIPTION OF THE REFERENCE CHARACTERS 
     
         
           1  roadside device 
           1   a  roadside sensor 
           1   b  communication unit 
           2  detection area of roadside sensor 
           3  own vehicle 
           4  detection area of on-vehicle sensor 
           5 ,  5   a  other vehicle 
           40  on-vehicle sensor 
           50  processing circuit 
           51  processor 
           52  memory 
           53  storage medium 
           54  program 
           100 ,  200 ,  300  communication device 
           101  second obstacle detection unit 
           102  overlap information removing unit 
           103  wireless transmission unit 
           104  first obstacle extraction unit 
           105  wireless receiving unit 
           201  detection area estimation unit 
           301  detection accuracy extraction unit