JP5842649B2 - Communication system, roadside communication device, and method of detecting abnormality in communication area - Google Patents

Description

  The present invention relates to a communication system, a roadside communication device, and a method for detecting an abnormality in a communication area.

In recent years, for the purpose of promoting traffic safety and preventing traffic accidents, advanced road traffic systems that improve the safety of vehicles by receiving information from infrastructure devices installed on the road and utilizing this information have been studied. (For example, refer to Patent Document 1).
A communication system forming a part of such an intelligent road traffic system includes a plurality of roadside communication devices that are wireless communication devices on the infrastructure side, and a plurality of in-vehicle communication devices that are wireless communication devices mounted on each vehicle. .

  In this case, a combination of communication performed between communication subjects includes road-to-road communication between road-side communication devices, road-to-vehicle (or vehicle-road) communication between road-side communication devices and vehicle-mounted communication devices, and vehicle-mounted communication. Vehicle-to-vehicle communication performed by the aircraft may be included.

Japanese Patent No. 2806801

  When communication areas (downlink areas) of a plurality of roadside communication devices that perform transmission at the same timing overlap, radio wave interference occurs in the overlapping range. Therefore, the communication areas of a plurality of roadside communication devices that perform transmission at the same timing should be set so as not to overlap as much as possible.

  Here, the communication area (downlink area) is a service area in which information such as traffic information is provided from the roadside communication device to the vehicle (onboard communication device). For example, the radius is 200 m centering on the roadside communication device. It is set to a size of about. And the magnitude | size of the transmission power of a roadside communication apparatus is set so that an electromagnetic wave may arrive in the set communication area.

Even if it is set so that the communication areas of multiple roadside communication devices do not overlap, in reality, due to changes in the radio wave propagation environment, radio waves transmitted from roadside communication devices are actually The reachable area (actual communication area) may expand and cause interference.
Conversely, due to changes in the radio wave propagation environment, the area where the radio waves transmitted from the roadside communication device actually reach (actual communication area) becomes smaller than the expected communication area, and the expected communication area Information may not be provided near the outer edge.

  Therefore, an object of the present invention is to provide a technique for detecting an abnormality in a communication area.

(1) The present invention is a communication system including a roadside communication device capable of transmitting information to an in-vehicle communication device and receiving transmission information transmitted by the in-vehicle communication device, wherein the roadside communication A roadside communication that is a transmission source of the information received by the in-vehicle communication device is included in the transmission information transmitted by the in-vehicle communication device. Information that can identify the machine is included, and in the determination process, the roadside communication device that is the transmission source of the information received by the in-vehicle communication device that has transmitted the transmission information is the roadside communication device that has received the transmission information. A reception determination process for determining whether or not there is based on the transmission information,
The said determination part is a communication system characterized by detecting abnormality of the communication area of the said roadside communication apparatus based on the said reception determination process.

  If the transmission information sent by the in-vehicle communication device contains information that can identify the roadside communication device that is the source of the information received by the in-vehicle communication device, the roadside communication device receives it if there is no abnormality in the communication area. The transmitted information should include information that can identify the roadside communication device. Therefore, an abnormality in the communication area is detected by determining whether or not the roadside communication device that is the transmission source of the information received by the in-vehicle communication device that has transmitted the transmission information is the roadside communication device that has received the transmission information. It becomes possible.

(2) The transmission information transmitted by the in-vehicle communication device includes information indicating the position of the in-vehicle communication device, and the determination process includes the position of the in-vehicle communication device that transmitted the transmission information in the transmission A position determination process is further included based on the transmission information to determine whether or not the communication area of the roadside communication apparatus that has received the information is received. It is preferable to perform the reception determination process when it is determined that the position is within the communication area of the roadside communication device that has received the transmission information.
By performing the position determination process, the vehicle-mounted communication device outside the communication area can be excluded from the abnormality detection target.

(3) In the reception determination process, when it is determined that the roadside communication device that is the transmission source of the information received by the in-vehicle communication device is not the roadside communication device that has received the transmission information, the in-vehicle communication device It is preferable to determine whether or not is in a state where it can be received from another roadside communication device other than the roadside communication device that has received the transmission information. The type or degree of the abnormality differs depending on whether the in-vehicle communication device can receive from other roadside communication devices other than the roadside communication device that received the transmission information. It is also possible to specify the type or degree.

(4) The transmission information transmitted by the in-vehicle communication device includes the time that the roadside communication device that is the transmission source of the information received by the in-vehicle communication device occupied the time slot used for communication for the transmission of information. In the reception determination process, the time indicated by the time information is the same as the time occupied by the roadside communication device that has received the transmission information used for communication to transmit the information. It is preferable that the determination is made based on whether or not.
In this case, the time information indicating the time occupied for the transmission of the time slot used for communication is used for identifying the roadside communication device, thereby directly identifying the roadside communication device (information of the roadside communication device). Even if the ID or the like is not included in the transmission information, the roadside communication device can be identified.

(5) The determination unit determines that the position of the in-vehicle communication device that has transmitted the transmission information is within a communication area of a roadside communication device that has received the transmission information by the position determination process, and the reception If the roadside communication device that is the transmission source of the information received by the in-vehicle communication device that has transmitted the transmission information is determined not to be the roadside communication device that has received the transmission information, the communication area is abnormal. It is preferable to detect this.

(6) An abnormality mitigation processing unit that performs a process of mitigating abnormality in the communication area is further provided, and the abnormality mitigation processing unit performs abnormality mitigation processing when the determination unit detects that the communication area is abnormal. Preferably it is performed. In this case, the abnormality in the communication area can be alleviated.

(7) It is preferable that the abnormality mitigation process includes a transmission power adjustment process of the roadside communication device.

(8) It is preferable that the abnormality mitigation process includes a process of changing a time slot assigned to the roadside communication device.

(9) The abnormality mitigation process includes a process for adjusting transmission power of a roadside communication device and a process for changing a time slot allocated to a roadside communication device, and the abnormality mitigation processing unit includes the abnormality in a communication area. After the adjustment process is executed as the mitigation process, it is preferable that the change process is still executed as the abnormality mitigation process when it is detected that the communication area is abnormal. In this case, it is possible to reduce the execution frequency of the time slot changing process that tends to be a complicated process.

(10) The present invention viewed from another viewpoint is a roadside communication device that transmits information to an in-vehicle communication device, the receiving unit receiving transmission information transmitted by the in-vehicle communication device, and the transmission information A determination unit that performs a determination process related to a communication area, and the transmission information transmitted by the in-vehicle communication device is information that can identify the roadside communication device that is the transmission source of the information received by the in-vehicle communication device In the determination process, whether or not the roadside communication device that is the transmission source of the information received by the in-vehicle communication device that transmitted the transmission information is its own device, A roadside communication device including a reception determination process for determining.

(11) The present invention viewed from another viewpoint is a method for detecting an abnormality in a communication area, and a roadside communication device capable of transmitting information to an in-vehicle communication device transmits transmission information transmitted by the in-vehicle communication device. And a step of performing a determination process on the communication area based on the transmission information received by the roadside communication device to detect an abnormality in the communication area of the roadside communication device, The transmission information transmitted by the machine includes information that can identify the roadside communication device that is the transmission source of the information received by the in-vehicle communication device, and the determination processing includes the in-vehicle communication device that has transmitted the transmission information. Includes a reception determination process for determining, based on the transmission information, whether or not the roadside communication device that is the transmission source of the received information is the roadside communication device that has received the transmission information. Is the method .

  According to the present invention, it is possible to detect an abnormality in a communication area.

It is a schematic perspective view which shows one Embodiment of an intelligent road traffic system. It is a figure which shows the structure and allocation method of a slot. It is a data structure figure of a vehicle-to-vehicle communication packet. It is a block diagram of a roadside communication apparatus and a central apparatus. It is a flowchart which shows the procedure regarding abnormality detection. (A) is a figure which shows a vehicle-to-vehicle communication packet when there is no abnormality, and (b) is a figure which shows a vehicle-to-vehicle communication packet when there is an abnormality. It is a flowchart of a determination process. (A) is a flowchart which shows the 1st example of abnormality relief processing, (b) is a flowchart which shows the 2nd example of abnormality relief processing. It is a flowchart which shows the 3rd example of abnormality mitigation processing.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[Overall system configuration]
FIG. 1 is a schematic perspective view showing an overall configuration of an intelligent road traffic system (ITS) according to an embodiment of the present invention. In this embodiment, as an example of the road structure, a grid structure in which a plurality of roads in the north-south direction and the east-west direction intersect with each other is assumed.
As shown in FIG. 1, the intelligent transportation system of this embodiment includes a traffic signal 1, a roadside communication device (radio device) 2, an in-vehicle communication device (radio device) 3 mounted on a vehicle 5, a central device 4, and A roadside sensor 6 composed of a vehicle sensor, a monitoring camera, or the like is included.

The traffic signal 1 and the roadside communication device 2 are installed at each of a plurality of intersections A1 to A5, B1 to B5, C1 to C5, and D1 to D5, and are connected to the router 8 via a wired communication line 7 such as a telephone line. It is connected. This router 8 is connected to the central device 4 in the traffic control center.
The central device 4 constitutes a local area network (LAN) with the traffic signal device 1 and the roadside communication device 2 in the area that the central device 4 has jurisdiction over. The central device 4 may be installed on the road instead of the traffic control center.

The roadside sensor 6 is installed in various places on the road in the jurisdiction area for the purpose of counting the number of vehicles flowing into each intersection. The roadside sensor 6 is composed of a vehicle sensor for ultrasonically sensing the vehicle 5 passing underneath, or a monitoring camera for photographing road traffic conditions in time series, and the sensing information and image data are transmitted via the communication line 7. To the central device 4.
In FIG. 1, for simplification of illustration, only one signal lamp is depicted at each intersection. However, at each actual intersection, at least four signal lamps are used for ascending and descending roads that intersect each other. Is installed.

In an intelligent road traffic system, a plurality of roadside communication devices (radio devices) 2 installed at each of a plurality of intersections constituting a wireless communication system are wirelessly communicated with an in-vehicle communication device 3 of a vehicle 5 that travels around the communication devices. Communication (road-to-vehicle communication) is possible.
An in-vehicle communication device (radio device) 3 that also constitutes a wireless communication system performs wireless communication with the roadside communication device 2 and also wirelessly communicates with other in-vehicle communication devices 3 using a carrier sense method (inter-vehicle communication). Is possible.

[Wireless communication systems, etc.]
FIG. 2 shows a radio frame used in the radio communication system. This radio frame has a length in the time axis direction set to 100 milliseconds, and includes a first slot SL1 and a second slot SL2.
The first slot SL1 is a time slot for road-to-vehicle communication assigned to the roadside communication device 2, and wireless transmission by the roadside communication device 2 is allowed in this time zone.
On the other hand, the second slot SL2 is a time slot for the in-vehicle communication device 3, and since this time period is opened for wireless transmission by the in-vehicle communication device 3, the roadside communication device 2 performs wireless transmission in the second slot SL2. Absent.

The first slots SL1 and the second slots SL2 included in the radio frame are alternately arranged in the time axis direction.
Each first slot SL1 is assigned a slot number i.

The roadside communication device 2 is assigned one of a plurality of first slots SL1 (for example, ten first slots) included in the radio frame. The roadside communication device 2 recognizes which slot is assigned to itself by the slot number i.
For example, the first slot SL1 with i = 1 is assigned to the roadside communication device 2 at the intersections A2, B5, C3, D1, and the first slot SL1 with i = 2 is assigned to the intersections A3, B1, C4, D2. Assigned to the roadside communication device 2 and assigned to the first slot SL1 of i = 3 is assigned to the roadside communication device 2 of the intersections A4, B2, C5 and D3, and the intersection A5 is assigned to the first slot SL1 of i = 4. It is assigned to the roadside communication devices 2 of B3, C1, and D4, and is assigned to the roadside communication device 2 of intersections A1, B4, C2, and D5 in the first slot SL1 of i = 5.

When the same first slot SL1 is assigned to the roadside communication device 2 at the adjacent intersection, the vehicle 5 between the adjacent intersections receives radio waves of road-to-vehicle communication from both roadside communication devices 2, Interference occurs. However, as shown in FIG. 2, by distributing and assigning the same first slots SL <b> 1, it becomes easy to prevent interference during road-to-vehicle communication by each roadside communication device 2.
In other words, the positional relationship between the roadside communication devices 2 to which the same first slot SL1 is assigned is set to a distance that is sufficiently distant from each other so that the transmission signals do not cause much interference. Are different from each other, different slots are assigned to each other.

  A plurality of the radio frames are arranged side by side in the time axis direction, and there is only one first slot SL1 of each slot number assigned to any roadside communication device 2 in each radio frame. The first slots SL1 of the respective slot numbers are periodically arranged with the radio frame length (100 milliseconds) as one cycle. Accordingly, each roadside communication device 2 performs transmission using the first slot SL1 every 100 milliseconds.

[Transmission by roadside communication device]
The first slot (road-to-vehicle communication time slot) SL1 has a maximum transmission time (for example, several milliseconds) assumed to be necessary for transmission (road-to-vehicle communication) by the roadside communication device 2, The time length of each first slot SL1 is constant.

On the other hand, in the first slot SL1, the data length (data amount) of the road-to-vehicle communication packet (data for road-to-vehicle communication) broadcast from the roadside communication device 2 to the vehicle 5 (the vehicle-mounted communication device 3) is roadside It depends on the communication device 2. For example, the roadside communication device 2 installed on the main road tends to increase the data amount of information to be provided to the in-vehicle communication device 3.
On the other hand, the roadside communication device 2 installed on a road with few passing vehicles reduces the data amount of information to be provided to the in-vehicle communication device 3.

Therefore, the roadside communication device 2 does not use the entire first slot SL1 assigned to the own device 2 for transmitting information (traffic information) to the vehicle 5, but uses only a part thereof. That is, the roadside communication device 2 transmits information (traffic information) that the own device 2 should transmit to the vehicle 5 in the road-to-vehicle communication packet in the time length of the first slot SL1 allocated to the own device 2. The remaining time is used as transmission time, and the remaining time is used for transmission. This idle time can be used for wireless transmission for other purposes (for example, transmission to other roadside communication devices (inter-road communication)).
Hereinafter, the time (occupation time) required to transmit information (traffic information) to be transmitted by the roadside communication device 2 in the road-to-vehicle communication packet is referred to as “data provision time”.

  In the present embodiment, the data provision times of the plurality of roadside communication devices 2 that use the same first slot SL1 are set differently. Thereby, it becomes possible to distinguish the roadside communication apparatus 2 which is the transmission source of the information which the vehicle-mounted communication apparatus 3 received by the difference in data provision time (it mentions later for details).

For example, the data provision times of a plurality of roadside communication devices 2 (roadside communication devices at intersections A2, B5, C3, and D1) using the slot number i = 1 are all set to be different. The same applies to the other slot numbers i = 2, 3, 4, 5,.
When a plurality of roadside communication devices 2 that use the same first slot SL1 are sufficiently separated from each other such that there is no possibility of occurrence of interference, data of each of the roadside communication devices 2 is used. The provision time may be the same. That is, although it is usually separated to such an extent that interference does not occur, depending on the propagation environment, the data providing time seems to be different for a plurality of roadside communication devices 2 that are likely to cause interference. Set to

  The roadside communication device 2 transmits information indicating the slot number i of the first slot SL1 assigned to the own device 2 and provision time information indicating the data provision time by the own device 2 in a road-to-vehicle communication packet. .

  The in-vehicle communication device 3 performs a process of synchronizing the radio frame transmitted by the roadside communication device 2. The vehicle-mounted communication device 3 that has received the road-to-vehicle communication packet once, based on the slot number i assigned to the road-side communication device 2 and the data provision time, the next road-to-vehicle communication packet that the road-side communication device 2 transmits. You can recognize when it starts and when it ends.

[Transmission via in-vehicle communication device]
The in-vehicle communication device 3 performs radio transmission by the CSMA method in the second slot SL2. FIG. 3 shows a vehicle communication packet (transmission information) that the in-vehicle communication device 3 transmits to another in-vehicle communication device 3. The inter-vehicle communication packet includes a header and a data body. The header includes FI information, and the FI information includes a slot number and provision time information. In addition to information such as the speed of the vehicle 5, the data body includes position information indicating the position of the vehicle 5 (for example, a position indicated by latitude and longitude).

The slot number included in the vehicle-to-vehicle communication packet is the roadside communication device 2 that transmitted the road-to-vehicle communication packet received by the in-vehicle communication device 3 that transmitted the vehicle-to-vehicle communication packet (hereinafter referred to as “transmission source roadside communication device 2”). Is the number of the slot assigned to.
The provision time information included in the inter-vehicle communication packet is information indicating the data provision time of the transmission source roadside communication device 2.

The vehicle-mounted communication device 3 that has received the vehicle-to-vehicle communication packet starts timing of the next road-to-vehicle communication packet that the roadside communication device 2 transmits next based on the slot number of the FI information and the provision time information included in the vehicle-to-vehicle communication packet. Can be recognized.
Since the destination of the vehicle-to-vehicle communication packet is not limited, the roadside communication device 2 can also receive the same as the vehicle-mounted communication device 3.

[Communication area error detection]
FIG. 4 shows the configuration of the roadside communication device 2 and the central device 4 according to this embodiment.
The roadside communication device 2 includes a wireless communication unit (transmitter / receiver) 21 to which an antenna 20 for wireless communication is connected, a wired communication unit 22 for communicating with the central device 4 through the wired communication line 7, and communication A processing unit 23 that performs processing such as control and a storage unit 24 that stores necessary information are provided.
The central device 4 includes a database 41 for accumulating acquired information, and an abnormality mitigation processing unit 42 that performs processing for mitigating abnormalities in the communication area. Note that any one or a plurality of roadside communication devices 2 may have the function of the central device 4.

FIG. 5 shows a processing procedure for detecting an abnormality in the communication area.
The roadside communication equipment 2, the first slot SL1 assigned to the own apparatus 2 (e.g., the slot number i = 2 slots), the transmits the road-vehicle communication packet data serving time ₌ T A [msec] (Step S1 -1).

  As shown in FIG. 6A, when there is no interference from other roadside communication, the in-vehicle communication device 3 in the communication area (downlink area) of the roadside communication device 2 in FIG. A road-vehicle communication packet transmitted from the communication device 2 can be received (step S2-1).

The in-vehicle communication device 3 that has received the road-to-vehicle communication packet transmitted from the roadside communication device 2 transmits the inter-vehicle communication packet to relay information to the other in-vehicle communication device 3 (step S2-2). Its inter-vehicle communication packet, the number of vehicle communication device 3 is allocated to the source roadside communication device 2 of the vehicle communication packet received slot (i = 2), information indicating the data providing time = T _A , And stored as FI information. The inter-vehicle communication packet stores position information indicating the position of the vehicle 5 equipped with the in-vehicle communication device 3 that has transmitted the inter-vehicle communication packet.

  The inter-vehicle communication packet is mainly information transmitted to another in-vehicle communication device 3. However, the roadside communication device 2 is monitoring the inter-vehicle communication packet transmitted in its own communication area, and can receive the inter-vehicle communication packet (step S1-2).

  The processing unit 23 of the roadside communication device 2 that has received the inter-vehicle communication packet recognizes the FI information and the vehicle position information (step S1-3). The determination unit 23a of the processing unit 23 performs a determination process regarding the communication area based on the recognized FI information and vehicle position information (step S1-4). Details of the determination process will be described later.

The roadside communication device 2 transmits the result of the determination process to the central device 4 as necessary (step S1-5).
When the central apparatus 4 receives the determination result (step S3-1), the central apparatus 4 accumulates the received determination result in the database 41 (step S3-2). The anomaly mitigation processing unit 42 of the central device 4 performs an anomaly mitigation process for mitigating anomalies in the communication area as needed based on the determination results accumulated in the database (step S3-3). Details of the abnormality mitigation process will also be described later.

As shown in FIG. 7, in the determination process (step S1-4), the position determination process (step S1-4-1) and the reception determination process (S1-4-1 to S1-4-6) are performed. Is called.
In the position determination process, determination is performed based on vehicle position information (information indicating the position of the in-vehicle communication device) included in the inter-vehicle communication packet (transmission information) received by the roadside communication device 2. In the position determination process, it is determined whether or not the position of the in-vehicle communication device 3 (vehicle 5) that has transmitted the inter-vehicle communication packet is within the communication area of the roadside communication device 2 based on the vehicle position information.

The communication area of the roadside communication device 2 is set, for example, as a range having a radius of 200 m centering on the roadside communication device 2. The transmission power of the roadside communication device 2 is set according to the size of the set communication area. However, even if the transmission power is the same, the reachable distance of the radio wave varies depending on the propagation path environment, so the set communication area and the actual communication area do not always match.
In the position determination process, it is determined whether or not the vehicle 5 exists in the communication area of the roadside communication device 2 by comparing the set communication area with the vehicle position information. The set communication area is stored in the storage unit 24. Therefore, the determination unit 23 a performs position determination by determining whether or not the vehicle position indicated by the vehicle position information is within the communication area stored in the storage unit 24.

  By performing the position determination process, the vehicle 5 (in-vehicle communication device 3) outside the set communication area (outside the service area) can be excluded from the objects to be considered for detecting the communication area abnormality. That is, for the roadside communication device 2, vehicles outside the set communication area (outside the service area) in the own device 2 are not subject to information provision, so the road-to-vehicle communication packet transmitted from the own device 2 arrives. There is no need to check whether or not.

When it is determined by the position determination process that the vehicle 5 is within the communication area of the roadside communication device 2, the determination unit 23a performs a reception determination process.
In the reception determination process, whether or not the transmission side roadside communication device of the road-to-vehicle communication packet received by the in-vehicle communication device 3 that has transmitted the vehicle-to-vehicle communication packet is the own device 2 is provided in the provided time information included in the FI information. It is determined by checking (step S1-4-2).

  That is, the determination unit 23a determines whether or not the provision time indicated by the provision time information included in the received inter-vehicle communication packet matches the provision time of the road-to-vehicle communication packet transmitted by the own device 2. If they match, the communication area abnormality is not detected (step S1-4-3). If they match, the road-to-vehicle communication packet transmitted by the roadside communication device 2 is correctly received by the in-vehicle communication device 3 existing in the communication area of the own device 2, as shown in FIG. There is no abnormality in the communication area.

On the other hand, if the data provision time indicated by the provision time information included in the received inter-vehicle communication packet is inconsistent with the provision time of the road-to-vehicle communication packet transmitted by the own device 2, there is an abnormality in the communication area. (Communication area abnormality detection).
That is, as shown in FIG. 6B, for the communication area of the first roadside communication device 2A, from the second roadside communication device 2B that uses the same time slot (for example, slot number i = 2). If there is a radio wave interference, even the in-vehicle communication device 3 located in the communication area of the first roadside communication device 2A may receive the road-to-vehicle communication packet transmitted from the second roadside communication device 2B. There is.

Here, the data providing time of the first roadside communication equipment 2A = a T _A, and a data providing time = T _B of the second roadside communication equipment 2B.
In this case, if the in-vehicle communication device 3 located in the communication area of the first roadside communication device 2A receives the road-to-vehicle communication packet transmitted from the second roadside communication device 2B that is the interference source, providing time information vehicle communication device 3 is included in the inter-vehicle communication packet to be transmitted is the T _a rather, the T _B (see Figure 6 (b)).

Therefore, the reception determination processing, provides the time information included in the inter-vehicle communication packet, by checking whether the provision time of the own device 2A (T _A), detecting an abnormality in the communication area of the own apparatus 2A can do.
In addition, if the vehicle-to-vehicle communication packet includes information (for example, the ID of the roadside communication device 2) that can directly identify the transmission source roadside communication device 2, the information matches the information of the own device 2. Depending on whether or not, an abnormality may be detected.

When providing the time information included in the inter-vehicle communication packet is not the provision time of the own device 2A (T _A), as the abnormality in the communication area, communication area actual communication area of another roadside communication device 2B has been set There is a case in which interference occurs so as to overlap with the communication area of the own device 2A. As another abnormality of the communication area, the actual communication area of the own device 2 may be smaller than the set communication area.

  In any case, the in-vehicle communication device 3 existing in the (set) communication area of the roadside communication device 2A cannot receive the road-vehicle communication packet from the roadside communication device 2A.

When there is an abnormality in the communication area, the provision time information included in the inter-vehicle communication packet indicates the provision time (T _B ) of the other roadside communication device 2B, and the provision time information may be missing. The provision time information is missing because, for example, the power of radio waves from both roadside communication devices 2A and 2B is substantially equal when viewed from the in-vehicle communication device 3, and the road-to-vehicle communication packet from any roadside communication device 2A or 2B cannot be received. Is the case. Also, when the transmission power of the own device 2A is too small and the radio wave does not reach the in-vehicle communication device 3, the provision time information is lost.

Therefore, in this embodiment, provision time information included in the inter-vehicle communication packet, if not provide time of its own 2A (T _A) is go further, missing provision time information included in the inter-vehicle communication packet Whether or not the provision time information of any other roadside communication device 2B is stored (step S1-4-4).

When the provision time information included in the inter-vehicle communication packet is provision time information (T _B ) of the other roadside communication device 2, the determination unit 23a detects a severe abnormality (first abnormality; interfered abnormality). (Step S1-4-5). When the provision time information included in the inter-vehicle communication packet is missing, the determination unit 23a detects a minor abnormality (second abnormality; insufficient communication area) (step S1-4-6).

  Note that step S1-4-4 can be omitted if it is not necessary to detect the type of abnormality and it is only necessary to detect whether there is an abnormality in the communication area.

  When the roadside communication device 2 detects an abnormality, the roadside communication device 2 transmits the abnormality to the central device 4 as a determination result of the determination process. The information included in the determination result to be transmitted can include information indicating the occurrence of abnormality, information indicating the type of abnormality, the position of the vehicle that transmitted the inter-vehicle communication packet that is the source of the abnormality detection, and the like. .

[Abnormality mitigation processing]
When the central apparatus 4 receives the determination result of the determination process transmitted from each of the plurality of roadside communication devices 2 (step S3-1), the determination result is stored in the database 41 for each roadside communication device 2. . Thereby, the traffic control center can analyze and grasp the state of occurrence of abnormality (abnormality occurrence position / abnormality occurrence frequency) in each communication area of the plurality of roadside communication devices 2.

In addition, the abnormality mitigation processing unit 42 of the central device 4 performs processing for mitigating the abnormality in the communication area on the roadside communication device 2 in which the abnormality is detected in the communication area (step S3-3).
8 and 9 show an example of the abnormality mitigation process.

  In the first example of the abnormality mitigation process shown in FIG. 8A, the adjustment process for transmitting the command for adjusting the transmission power of the roadside communication device 2 in which an abnormality is detected to the roadside communication device 2 is performed as the abnormality mitigation processing. (Step S3-3-1). The roadside communication device 2 that has received the transmission power adjustment command from the central device 4 adjusts the transmission power of the own device 2 based on the command. For example, in the roadside communication device 2 in which an abnormality is detected, information from the own device 2 does not reach the set communication area, so that the actual communication area is the same as the set communication area. Electric power can be increased.

  Further, the adjustment process may be a process of adjusting the transmission power of another roadside communication device 2 that has interfered with the communication area of the roadside communication device 2 in which an abnormality has been detected. For example, the abnormality mitigation processing unit 42 identifies the other roadside communication device 2 based on the abnormality occurrence position and the slot number, and reduces the transmission power of the other roadside communication device 2 so as not to cause interference. Can be made.

In the second example of the abnormality mitigation process shown in FIG. 8B, a change process for changing the time slot (first slot SL1) assigned to the roadside communication device 2 and / or another roadside communication device in which an abnormality is detected. Is performed as an abnormality mitigation process (step S3-3-2). The time slot is changed by transmitting a command for changing the time slot to be used (first slot SL1) from the central device 4 to the roadside communication device 2, and the time used by the roadside communication device 2 receiving the command. This is done by changing the slot.
Interfering with each other. If the time slots are not the same, no interference occurs in the first place. Therefore, the interference can be avoided by changing the time slot of the roadside communication device 2 in which the interference occurs.

In the third example of the abnormality mitigation process shown in FIG. 9, first, as the abnormality mitigation process, the same adjustment process as in step S3-3-1 is executed (steps S3-3-3, S3-3-5), and transmission is performed. If the abnormality still occurs after the power adjustment, the time slot changing process is performed (step S3-3-4).
When the time slot assigned to a certain roadside communication device 2 is changed, it is necessary to change the time slots around the roadside communication device 2 and the processing is complicated. Therefore, by executing the adjustment process that is relatively easy to execute in advance and performing the change process when the abnormality cannot be resolved by the adjustment process, the frequency of executing the complicated change process can be reduced.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is not meant to be described above, but is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Traffic signal device 2 Roadside communication device 3 In-vehicle communication device 4 Central apparatus 5 Vehicle 6 Roadside sensor 7 Wired communication line 8 Router 20 Antenna 21 Wireless communication unit 22 Wired communication unit 23 Processing unit 24 Storage unit 41 Database 42 Abnormality mitigation processing unit

Claims (11)

A communication system including a roadside communication device capable of transmitting information to an in-vehicle communication device and receiving transmission information transmitted by the in-vehicle communication device,
Based on the transmission information received by the roadside communication device, comprising a determination unit that performs a determination process related to a communication area,
The transmission information transmitted by the in-vehicle communication device includes information that can identify the roadside communication device that is the transmission source of the information received by the in-vehicle communication device,
In the determination process, whether or not the roadside communication device that is the transmission source of the information received by the in-vehicle communication device that has transmitted the transmission information is the roadside communication device that has received the transmission information in the transmission information. A reception determination process for determining based on,
The said determination part detects abnormality of the communication area of the said roadside communication apparatus based on the said reception determination process. The communication system characterized by the above-mentioned. The transmission information transmitted by the in-vehicle communication device includes information indicating the position of the in-vehicle communication device,
In the determination process, a position for determining whether the position of the in-vehicle communication device that has transmitted the transmission information is within the communication area of the roadside communication device that has received the transmission information, based on the transmission information. Further includes a determination process,
The determination unit performs the reception determination process when the position determination process determines that the position of the in-vehicle communication device is within a communication area of a roadside communication device that has received the transmission information. The communication system according to claim 1. In the reception determination process, when it is determined that the roadside communication device that is the transmission source of the information received by the in-vehicle communication device is not the roadside communication device that has received the transmission information, the in-vehicle communication device further transmits the transmission The communication system according to claim 1 or 2, wherein it is determined whether or not the information is received from a roadside communication device other than the roadside communication device that has received the information. The transmission information transmitted by the in-vehicle communication device includes time information indicating the time taken by the roadside communication device, which is the transmission source of the information received by the in-vehicle communication device, to occupy the time slot used for communication. Including
The reception determination process is performed by determining whether or not the time indicated by the time information is the same as the time occupied by the roadside communication device that has received the transmission information used for communication to transmit the information. The communication system according to any one of claims 1 to 3. The determination unit determines that the position of the in-vehicle communication device that has transmitted the transmission information is within the communication area of the roadside communication device that has received the transmission information by the position determination processing, and the reception determination processing The communication area is abnormal when it is determined that the roadside communication device that is the transmission source of the information received by the in-vehicle communication device that has transmitted the transmission information is not the roadside communication device that has received the transmission information. The communication system according to claim 2. It further includes an abnormality mitigation processing unit that performs processing to mitigate abnormality in the communication area
The communication system according to any one of claims 1 to 5, wherein the abnormality mitigation processing unit executes an abnormality mitigation process when the determination unit detects that a communication area is abnormal. The communication system according to claim 6, wherein the abnormality mitigation process includes a process for adjusting transmission power of a roadside communication device. The communication system according to claim 6 or 7, wherein the abnormality mitigation process includes a process of changing a time slot assigned to a roadside communication device. The abnormality mitigation process includes a process for adjusting the transmission power of the roadside communication device, and a time slot change process assigned to the roadside communication device,
The abnormality mitigation processing unit, after executing the adjustment process as the abnormality mitigation process of the communication area, still executes the change process as an abnormality mitigation process when it is detected that the communication area is abnormal. Item 7. The communication system according to Item 6. A roadside communication device that transmits information to an in-vehicle communication device,
A receiving unit for receiving transmission information transmitted by the in-vehicle communication device;
A determination unit that performs a determination process on a communication area based on the transmission information;
With
The transmission information transmitted by the in-vehicle communication device includes information that can identify the roadside communication device that is the transmission source of the information received by the in-vehicle communication device,
The determination process includes determining whether the roadside communication device that is the transmission source of the information received by the in-vehicle communication device that transmitted the transmission information is the own device based on the transmission information. A roadside communication device characterized in that it includes processing. A method for detecting an abnormality in a communication area,
A roadside communication device capable of transmitting information to the in-vehicle communication device receives the transmission information transmitted by the in-vehicle communication device; and
Based on the transmission information received by the roadside communication device, performing a determination process related to a communication area, and detecting an abnormality in the communication area of the roadside communication device;
Including
The transmission information transmitted by the in-vehicle communication device includes information that can identify the roadside communication device that is the transmission source of the information received by the in-vehicle communication device,
In the determination process, whether or not the roadside communication device that is the transmission source of the information received by the in-vehicle communication device that has transmitted the transmission information is the roadside communication device that has received the transmission information in the transmission information. And a reception determination process for determining based on the method.

Images