JP2014014039A - Communication device, mobile station, radio communication system, and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a mobile station that received a communication packet from unnecessarily reading application data, when the mobile station cannot determine from the destination address of the communication packet whether the type of a destination communication device of the communication packet is a base station or a mobile station.SOLUTION: A communication packet transmitted by communication devices 2 and 3 includes information indicating a type of a destination communication device. The information indicating the type of the destination communication device is provided in a control field that is to be read by a layer higher than a MAC layer or a processing section accessed by the higher layer on the receiving side of the communication packet.

Description

  The present invention relates to, for example, a communication device suitable as a component of an intelligent transport system (ITS), a wireless communication system having a base station and a mobile station, and a computer program for the communication device. is there.

Conventionally, as a part of ITS, a wireless communication system having a base station installed on a roadside and a mobile station (such as an in-vehicle communication device mounted on a vehicle) has been studied.
Non-Patent Document 1 and Non-Patent Document 2 describe wireless communication systems for ITS.

  In a wireless communication system for ITS, a base station (roadside communication device) installed on the roadside transmits information to a mobile station (mobile communication device) mounted on the vehicle, Vehicle-to-vehicle communication for transmitting information between mounted mobile stations is performed.

By performing inter-vehicle communication, a mobile station mounted on a vehicle can transmit a communication packet storing application data including information such as the position and speed of the vehicle to another mobile station. It can be used for safe driving support that avoids collision with the vehicle.
Further, by performing road-to-vehicle communication, a base station installed on the roadside can transmit a communication packet storing application data such as the vehicle information or traffic signal information to the mobile station.

The Japan Radio Industry Association, "700MHz band Intelligent Transport System ARIB-STDT109 1.0 Edition", [online], February 14, 2012, [Search June 6, 2012], Internet <http: //www.arib.or.jp/tyosakenkyu/kikaku_tushin/tsushin_kikaku_number.html> ITS Information Communication System Promotion Conference, “700 MHz Band Intelligent Transportation System Extended Function Guidelines ITS FORUM RC-010 1.0 Edition”, [online], March 26, 2012, [Search June 6, 2012], Internet <http://www.itsforum.gr.jp/>

In a wireless communication system for ITS, it is required to receive as many communication packets as possible transmitted from a base station and a large number of mobile stations one after another.
Accordingly, connectionless communication is performed instead of connection-type communication in which a connection channel is established by exchanging ACK or the like between the transmission side and the reception side. Therefore, the receiving side needs to receive a communication packet unilaterally transmitted from the transmitting side, and even if reception fails, retransmission processing is not performed.

  Assuming only the above-mentioned road-to-vehicle communication and vehicle-to-vehicle communication as the communication performed in the wireless communication system, all the transmitted communication packets are directed to the vehicle (mobile station) as a mobile station (vehicle communication device etc.). Therefore, there is no problem in receiving a large amount of transmitted communication packets as much as possible.

However, in a wireless communication system for ITS, it is also considered to perform roadside communication for transmitting information between base stations (roadside communication devices) installed on the roadside.
When inter-road communication is performed, the mobile station should avoid receiving inter-road communication packets (inter-road communication packets) among communication packets from base stations installed on the roadside. is there.

  However, as described above, the mobile station is required to receive as much of a large number of transmitted communication packets as possible. Therefore, for example, in Non-Patent Document 1, only the broadcast address is defined as the destination address stored in the MAC control field of the communication packet. That is, the communication packet is used only for broadcast communication.

  If the communication packet is broadcast, the destination cannot be distinguished by the destination address. Even if the transmission source address can be specified, it is not easy to distinguish whether the transmission source communication device is a base station or a mobile station from only the address. Therefore, even if the mobile station refers to the address, it cannot distinguish whether the communication packet is for road-to-vehicle communication or road-to-road communication.

  Then, the mobile station reads the application data stored in the received communication packet and uses the application data if it is necessary for the mobile station. If the application data is data for the base station, It will be discarded without using it.

  As a result, when the mobile station receives the road-to-road communication packet, the mobile station wastes processing for reading unnecessary application data from the road-to-road communication packet. For this reason, the processing delay of the road-vehicle communication packet or the vehicle-vehicle communication packet which should be processed originally becomes large.

Such a problem may occur in common when the destination address of a communication packet cannot distinguish whether the type of communication device that is the destination of the communication packet is a base station or a mobile station.
The above problem also occurs when, for example, a mobile station transmits a communication packet (inter-road communication packet) for a base station.

  Therefore, the present invention provides that the mobile station that received the communication packet receives application data when the destination address of the communication packet cannot distinguish whether the type of communication device that is the destination of the communication packet is a base station or a mobile station. It is an object of the present invention to prevent the processing for reading out from being performed wastefully.

(1) The present invention is a communication device capable of transmitting a communication packet for a base station, and the communication packet transmitted by the communication device includes type information having information indicating a destination communication device type, The type information is a control field of the communication packet, and is provided in a control field read by a higher layer than the MAC layer or a processing unit accessed by the upper layer on the receiving side of the communication packet. Is a communication device.

According to the present invention, information indicating the destination communication device type is included in the communication packet transmitted by the communication device. Therefore, the mobile station which is the communication packet receiving side, even when the destination address itself is regarded as addressed to itself, as in the case where the destination address of the communication packet is a broadcast address, information indicating the type of communication device of the destination Based on the above, it is possible to determine whether or not the communication packet is to be acquired in the own station.
As a result, the mobile station can determine whether the received communication packet is necessary.

In addition, since the information is provided in a control field that is read in a higher layer than the MAC layer or a processing unit accessed by the upper layer on the receiving side of the communication packet, the information of the received communication packet is read before reading the application data. It is possible to determine necessity.
Therefore, it is possible to prevent the mobile station that has received the communication packet from wastefully performing the process for reading the application data.

(2) It is preferable that the information is information that can identify whether the communication device is a base station or a mobile station. In this case, whether the destination communication device is a base station or a mobile station can be identified by information indicating the communication device type.

(3) The communication device is used in a wireless communication system that can include a mobile station that complies with a standard in which only a broadcast address is defined as a destination address of a communication packet, and transmits a communication packet for a base station. In this case, it is preferable to set a non-broadcast address that is the destination of the base station as the destination address in the MAC control field of the communication packet.
In this case, the communication packet reaches the destination base station. On the other hand, a non-broadcast address is stored for a mobile station that complies with a standard in which only a broadcast address is defined as a destination address of a communication packet because the destination address of the communication packet is a broadcast address. The communication packet is expected to be discarded by the mobile station.

(4) The information is preferably provided in at least one of the following a) to d).
a) IR control field defined in 700 MHz band intelligent road traffic system standard (ARIB STD-T109) b) Layer 7 header defined in 700 MHz band intelligent road traffic system standard (ARIB STD-T109) c) 700 MHz band intelligent road EL header specified in the Transport System Extended Function Guidelines (ITS FORM RC-010) d) Field for security management of application data stored in communication packets

(5) The information is provided in a control field that is read before performing processing for converting secure application data subjected to security processing to unsecure application data on the receiving side of the communication packet. preferable. In this case, the information can be read before the process for converting the secure application data to the unsecure application data, and the process for converting the secure application data to the unsecure application data is wasted. Can be prevented.

(6) It is preferable that the communication packet is further provided with information indicating a communication device type of a transmission source as the type information. In this case, the receiving side of the communication packet can also grasp the communication device type of the transmission source.

(7) The present invention from another viewpoint is a communication device used in a wireless communication system that can include a mobile station that complies with a standard in which only a broadcast address is defined as a destination address of a communication packet. When transmitting the communication packet, the base station is characterized in that, as a destination address in the MAC control field of the communication packet, a non-broadcast address and a destination addressed by the other base station is set. .

In this case, a non-broadcast address is stored because the destination address of the communication packet is assumed to be a broadcast address for a mobile station conforming to a standard in which only the broadcast address is defined as the destination address of the communication packet. The communication packet is expected to be discarded by the mobile station.
Therefore, it is possible to prevent the mobile station that has received the communication packet from wastefully performing the process for reading the application data.

(8) The communication device can be used as a base station.
(9) The communication device can be used as a mobile station.

(10) From another viewpoint, the present invention is a mobile station that performs wireless communication between a base station and another mobile station, and reads information indicating a destination communication device type from the received communication packet. The communication packet is identified as to whether or not the communication packet is a communication packet transmitted to a base station. If the communication packet is a communication packet transmitted to a base station, the communication packet is discarded. The information is provided in a control field of the communication packet, which is provided in a control field read by a higher layer than the MAC layer in the mobile station or a processing unit accessed by the higher layer. It is a featured mobile station.

(11) Another aspect of the present invention is a wireless communication system including a base station and a mobile station that perform wireless communication, and the base station or the base station includes communication that includes information indicating a destination communication device type. The mobile station is configured to transmit a packet, and the mobile station reads the information from the received communication packet to identify whether the communication packet is a communication packet transmitted to a base station, and When the communication packet is a communication packet transmitted to a base station, the communication packet is configured to be discarded, and the information is a control field of the communication packet, and the receiving side of the communication packet In a control field read by a higher layer than the MAC layer or a processing unit accessed by the higher layer. It is a non.

(12) The present invention from another viewpoint is a computer program executed by a computer provided in a communication device capable of transmitting a communication packet for a base station, and includes information indicating a destination communication device type. The computer is configured to cause the computer to execute processing for generating a communication packet, and the information is a control field of the communication packet, and is accessed by a higher layer than the MAC layer or the higher layer on the communication packet receiving side A computer program provided in a control field read by a processing unit.

(13) The present invention viewed from another viewpoint is a computer program executed by a computer provided in a mobile station that performs wireless communication between a base station and another mobile station, from a received communication packet, A process for identifying whether the communication packet is a communication packet transmitted to a base station by reading information indicating a destination communication device type, and the communication packet is transmitted to the base station If the received packet is a communication packet, the computer is configured to execute processing for discarding the communication packet, and the information is a control field of the communication packet, and is higher than the MAC layer in the mobile station. Is provided in a control field that is read by a layer or a processing unit accessed by the upper layer. A gram.

  According to the present invention, even when the destination address of a communication packet cannot distinguish whether the type of communication device that is the destination of the communication packet is a base station or a mobile station, the mobile station that has received the communication packet can It is possible to suppress wasteful processing for reading data.

1 is a schematic perspective view showing an overall configuration of an intelligent road traffic system including a roadside communication device according to an embodiment of the present invention. It is a road top view which shows a part of jurisdiction area of the said intelligent road traffic system. It is a block diagram which shows the internal structure of a roadside communication apparatus and a vehicle-mounted communication apparatus. It is a conceptual diagram which shows an example of a time slot. It is a figure which shows a communication protocol stack. It is a block diagram of a communication frame. (A) shows a MAC control field, (b) shows an LLC control field, (c) shows an IR control field, and (d) shows an L7 header. It is a figure which shows the protocol stack which has an extended layer. It is a block diagram of the communication frame which has EL header. It is a figure which shows EL header. It is explanatory drawing of individual information and common information. It is explanatory drawing, such as destination communication apparatus classification information. It is explanatory drawing, such as destination communication apparatus classification information. It is explanatory drawing, such as destination communication apparatus classification information. It is explanatory drawing, such as destination communication apparatus classification information.

[Overall system configuration]
FIG. 1 is a schematic perspective view showing an overall configuration of an intelligent road traffic system (ITS). In FIG. 1, 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, an intelligent road traffic system includes a traffic signal 1, a base station 2 installed on the roadside, a mobile station 3 (see FIGS. 2 and 3) mounted on a vehicle, a central device 4, and a mobile station. It includes a mounted vehicle 5 and a roadside sensor 6 composed of various vehicle detectors. Hereinafter, the base station 2 installed on the roadside is referred to as “roadside communication device”, and the mobile station 3 mounted on the vehicle is referred to as “vehicle communication device”.
Note that the intelligent transportation system according to the present embodiment complies with the standards shown in Non-Patent Document 1 and the guidelines shown in Non-Patent Document 2.

The traffic signal 1 and the roadside communication device 2 are installed at each of a plurality of intersections Ji (i = 1 to 12 in the example), and are connected to the router 8 via a communication line 7 such as a telephone line. . 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 at each intersection Ji included in the area under its control. Therefore, the central device 4 can perform bidirectional communication with each traffic signal 1 and each roadside communication device 2. The central device 4 may be installed on the road instead of the traffic control center.

  In FIG. 1 and FIG. 2, only one signal lamp is depicted at each intersection Ji, which is a crossroad intersection, to simplify the illustration, but at each actual intersection Ji, up and down roads intersecting each other There are at least four signal lamps installed.

The roadside sensor 6 is composed of various vehicle detectors installed at appropriate places in the jurisdiction area for the purpose of counting the number of vehicles flowing into each intersection Ji and detecting the end of a traffic jam.
Examples of the vehicle detector include an ultrasonic vehicle detector, a microwave vehicle detector, an optical vehicle detector (light beacon), an “image type vehicle detector”, and a “travel time measurement sensor”. Can be adopted.

[Central equipment]
The central device 4 has a control unit including a workstation (WS), a personal computer (PC), and the like. This control unit collectively collects, processes (calculates) and records various types of traffic information from the roadside communication device 2 and the roadside sensor 6, performs signal control, and provides information.
Specifically, the control unit of the central device 4 performs system control for adjusting the traffic signal group 1 on the same road for the traffic signal 1 at the intersection Ji belonging to its own network, and this system control is applied to the road network. Extended wide area control (surface control) can be performed.

In addition, the central device 4 has a communication unit that is a communication interface connected to the LAN side via the communication line 7. This communication unit transmits a signal control command S1 relating to the color switching timing of the signal lamp and traffic information S2 including traffic jam information to the traffic signal 1 and the roadside communication device 2 every predetermined time (see FIG. 1). .
The signal control command S1 is transmitted every calculation period (for example, 1.0 to 2.5 minutes) of the signal control parameter when performing the system control and the wide area control, and the traffic information S2 is transmitted every 5 minutes, for example. Is done.

Further, the communication unit of the central device 4 receives vehicle information (application data) including the position and speed of the vehicle 5 received from the in-vehicle communication device 3 by the roadside communication device 2 from the roadside communication device 2 corresponding to each intersection Ji. S3 is received, and the sensing information S4 is received from the roadside sensor 6 installed on each road.
The control unit of the central device 4 can execute the system control and the wide area control based on the vehicle information S3 and the sensing information S4 acquired by the communication unit from the roadside communication device 2 and the roadside sensor 6 in the jurisdiction area. .

[Wireless communication systems, etc.]
FIG. 2 is a road plan view showing a part of the jurisdiction area of the above intelligent road traffic system.
In FIG. 2, each of two roads intersecting each other is illustrated as one lane on one side in the up and down directions, but the road structure is not limited to this.
As shown in FIG. 2, the intelligent road traffic system of this embodiment includes a plurality of roadside communication devices 2 capable of wireless communication with the in-vehicle communication device 3 and a mobile wireless transceiver that performs wireless communication using the CSMA method. A wireless communication system having a plurality of in-vehicle communication devices 3 that are a kind of

The roadside communication device 2 is installed at each roadside intersection Ji, and is attached to, for example, a column of the traffic signal 1 as illustrated in FIGS. 1 and 2. The in-vehicle communication device 3 is mounted on a vehicle 5 traveling on a road.
When the roadside communication device 2 can receive a radio signal from the in-vehicle communication device 3 in its own reception area Ar and the reception area Ar reaches the antenna of another roadside communication device 2, A radio signal from the other roadside communication device 2 can also be received.

In the roadside communication device 2 according to the present embodiment, a plurality of antennas 20a and 20b (see FIGS. 3 and 7) having directivity along the road extending direction are employed, so that the reception area Ar extends from the intersection J2 to the road. It is the shape extended along the extending direction.
In FIG. 2, only the reception area Ar of the roadside communication device 2 installed at the intersection J2 is illustrated, but the reception area Ar of the roadside communication device 2 installed at the other intersection Ji is also the intersection Ji. It has a shape that extends along the road extension direction.

In the intelligent transportation system of the present embodiment, wireless communication is used for communication between roadside communication devices 2 (roadside communication), and communication between the roadside communication device 2 and the in-vehicle communication device 3 (“road” Wireless communication is also used between the vehicle-to-vehicle communication devices 3 and the vehicle-mounted communication devices 3 (vehicle-to-vehicle communication). ing.
As described above, the central device 4 provided in the traffic control center is capable of two-way communication with each roadside communication device 2 by wire, but wireless communication may be performed between these devices.

The roadside communication device 2 is assigned a dedicated time slot (first slot T1 in FIG. 4) for wireless transmission by itself in the TDMA system, and a time slot other than this time slot (second slot in FIG. 4). No wireless transmission is performed in T2). Therefore, the time zone other than the time slot dedicated to the roadside is opened as the transmission time by the CSMA method for the in-vehicle communication device 3.
Further, the roadside communication device 2 has a time synchronization function with other roadside communication devices 2 in order to control its own transmission timing. The time synchronization of the roadside communication device 2 is performed by, for example, GPS synchronization that adjusts its own clock to the GPS time, air synchronization that adjusts its own clock to a transmission signal from another roadside communication device 2, or the like.

[Roadside communication equipment (base station)]
FIG. 3 is a block diagram showing the internal configuration of the roadside communication device 2 and the in-vehicle communication device 3.
The roadside communication device 2 includes a wireless communication unit (transmission / reception unit) 21 having antennas 20a and 20b for wireless communication, a wired communication unit 22 that performs bidirectional communication with the central device 4, and a processor (CPU) that performs communication control thereof. A central processing unit) and a storage unit 24 connected to the control unit 23, such as a ROM or a RAM.

  The storage unit 24 stores a computer program for communication control processing executed by the control unit (computer) 23, communication device IDs of the communication devices 2 and 3, and the like. The processing executed by the control unit 23 is performed by executing a computer program by the control unit 23.

  The wireless communication unit 21 includes two antennas 20a and 20b having directivity along the road direction of the intersection Ji, and a selection for selecting any one of the two antennas 20a and 20b as a reception antenna. The reception method is adopted. The specific configuration (FIG. 6) of the wireless communication unit 21 that employs the selective reception method will be described later.

The control unit 23 has a communication control function that comprehensively controls ITS application data transmitted and received by the wireless communication unit 21 and the wired communication unit 22.
For example, the control unit 23 temporarily stores the vehicle information (application data) S3 received by the wireless communication unit 21 from the in-vehicle communication device 3 in the storage unit 24 and transfers the vehicle information (application data) S3 to the central device 4 through the wired communication unit 22. Further, the control unit 23 temporarily stores traffic information (application data) S2 and the like received by the wired communication unit 22 from the central device 4 in the storage unit 24, and transmits a communication packet including the traffic information S2 to the wireless communication unit. 21 is broadcast.

In addition, the control unit 23 broadcasts a communication packet including time slot allocation information (application data) S <b> 5 stored in the storage unit 24 via the wireless communication unit 21. This allocation information S5 is information for notifying the in-vehicle communication device 3 of the transmission time of the roadside communication device 2 (first slot T1 in FIG. 4).
The in-vehicle communication device 3 of the vehicle 5 that has acquired the allocation information S5 from the roadside communication device 2 receives the carrier in a time zone (second slot T2 in FIG. 4) in which the roadside communication device 2 that transmitted the allocation information S5 does not transmit. Wireless transmission by sense method.

[Time slot allocation information]
FIG. 4 is a conceptual diagram showing an example of a time slot included in the allocation information S5.
As shown in FIG. 4, the time slot includes a first slot T1 and a second slot T2, and these slots T1 and T2 are a predetermined number of times within a predetermined length C (for example, 100 milliseconds). It is supposed to repeat.
The first slot T1 is a time slot for the roadside communication device 2, and wireless transmission by the roadside communication device 2 is permitted in this time zone. A slot number i is assigned to the first slot T1, and the slot number i is periodically incremented or decremented.

The second slot T2 is a time slot for the in-vehicle communication device 3. Since this time zone is opened for wireless transmission by the in-vehicle communication device 3, the roadside communication device 2 does not perform wireless transmission in the second slot T2.
In the time slot shown in FIG. 4, the dots ● marked in the first slot T1 of each slot number i = 1 to 3 indicate that the transmission times of the plurality of roadside communication devices 2 are assigned to the first slot T1. Show.

  That is, in the example shown in FIG. 4, the transmission times of the two roadside communication devices 2 at the intersections J1 and J5 (see FIG. 1) are allocated to the first slot T1 of the slot number (1), and the slot number (2 ) Is assigned to the transmission times of the three roadside communication devices 2 at the intersections J2, J6 and J8, and the first slot T1 of the slot number (3) is assigned to one roadside at the intersection J3. The transmission time of the communication device 2 is assigned.

Thus, the transmission time of each roadside communication device 2 is not assigned to the first slot T1 in a one-to-one correspondence, but for the roadside communication devices 2 installed at the intersection Ji where no radio wave interference occurs. The same slot number i can be assigned in duplicate.
Such slot allocation can be performed collectively by the central device 4, or each roadside communication device 2 can autonomously perform using the installation position and slot information acquired from other devices.
In addition, one parent device is selected in advance from a plurality of roadside communication devices 2, 2..., And this parent device has a transmission timing at which radio interference does not occur between the child devices that are the other roadside communication devices 2. As can be seen, slot allocation can also be performed.

[In-vehicle communication device]
Returning to FIG. 3, the in-vehicle communication device 3 includes a communication unit (transmission / reception unit) 31 having an antenna 30 for wireless communication, a control unit 32 including a processor that performs communication control on the communication unit 31, and the control unit. And a storage unit 33 including a storage device such as a ROM or a RAM connected to the storage unit 32.
The storage unit 33 stores a computer program for communication control processing executed by the control unit (computer) 32, communication device IDs of the communication devices 2 and 3, and the like. The processing executed by the control unit 23 is performed by executing a computer program by the control unit 32.

The control unit 32 of the in-vehicle communication device 3 causes the communication unit 31 to perform wireless communication by a carrier sense method for inter-vehicle communication, and a communication control function in a time division multiplexing method with the roadside communication device 2. Does not have.
Accordingly, the communication unit 31 of the in-vehicle communication device 3 always senses the reception level of a predetermined carrier frequency, and when the value is equal to or greater than a certain threshold, wireless transmission is not performed, and when the value is less than the threshold Only intended to perform wireless transmission.

The control unit 32 of the in-vehicle communication device 3 sends a communication packet including vehicle information (application data) S3 including the current position, direction, speed, and the like of the vehicle 5 (in-vehicle communication device 3) via the communication unit 31. Wireless transmission by broadcasting to the outside.
In addition, the control unit 32 of the in-vehicle communication device 3 has the position, speed, and direction included in the vehicle information S3 received directly from the other vehicle 5 or the vehicle information S3 of the other vehicle 5 received from the roadside communication device 2. Based on this, it is possible to perform safe driving support control for avoiding a right-handed collision or a head-on collision.

Further, when the communication unit 31 receives the time slot allocation information (application data) S5 broadcasted by the roadside communication device 2, the control unit 32 of the in-vehicle communication device 3 generates a communication frame including the allocation information S5. The wireless signal of this communication frame is broadcasted and the allocation information S5 is transferred to the other in-vehicle communication device 3.
Accordingly, the radio signal transmitted by the roadside communication device 2 in the downlink and the radio signal broadcasted by the vehicle-mounted communication device 3 outside the transmission area of the roadside communication device 2 are connected to the vehicle-mounted communication in the transmission area of the roadside communication device 2. It does not reach the machine 3 at the same time.

[Communication protocol stack]
FIG. 5 shows a communication protocol stack described in Non-Patent Document 1 to which the roadside communication device 2 and the in-vehicle communication device 3 comply.
The processing based on the function shown in FIG. 5 is executed by the control unit 23 of the roadside communication device 2 and the control unit 32 of the in-vehicle communication device 3.

  The protocol stack shown in FIG. 5 is defined with reference to the OSI reference model. Layer 1 (L1, Physical Layer), Layer 2 (L2, Data Link Layer), and inter-vehicle -It has a road-to-vehicle shared communication control information layer (IVC-RVC layer: Inter-Vehicle Communication-Road to Vehicle Communication Layer) and layer 7 (L7, application layer: Application Layer).

Layer 1 operates in accordance with a physical layer defined in IEEE 802.11.
Layer 2 includes a MAC sublayer (Medium Access Control sublayer) and an LLC sublayer (Logical Link Control sublayer). The MAC sublayer is also simply referred to as a MAC layer (Medium Access Control layer), and the LLC sublayer (Logical Link Control sublayer) is also simply referred to as an LLC layer (Logical Link Control layer).

The MAC layer uses the CSMA / CA method as communication control between the in-vehicle communication devices 3. The MAC layer performs frame control and broadcast communication (broadcast) as wireless channel communication management.
The LLC layer provides a connectionless communication service without confirmation in order to perform packet transmission between higher-layer entities.

  The inter-vehicle / road-vehicle shared communication control information layer (IVC-RVC layer) generates and manages information necessary for inter-vehicle / road-vehicle shared communication control. In Non-Patent Document 1, road-to-road communication is not defined, but when performing road-to-road communication as in this embodiment, in the vehicle-to-vehicle / road-vehicle shared communication control information layer (IVC-RVC layer), It is possible to generate and manage information necessary for communication control of road-to-road communication.

  Layer 7 is for providing communication control means to the application AP. The application AP gives the application data (traffic information, vehicle information, etc.) stored in the transmitted communication packet to the layer 7 and acquires the application data stored in the received communication packet from the layer 7.

Here, as an application of the roadside communication device (base station) 2, acquisition / generation of application data (traffic information, vehicle information, etc.) provided to the in-vehicle communication device 3 or other roadside communication device 2, An application that transmits the application data by communication control means provided by layer 7 is included.
As an application of the roadside communication device 2, application data (traffic information, vehicle information, etc.) received from the in-vehicle communication device 3 or another roadside communication device 2 by the communication control means provided by the layer 7 is acquired and processed. Or an application to transfer is included.

Further, as an application of the in-vehicle communication device 3, application data (traffic information, vehicle information, etc.) provided to other in-vehicle communication device 3 or roadside communication device 2 is acquired and generated, and the application data is layered. 7 includes an application for transmitting by the communication control means provided by 7.
As an application of the in-vehicle communication device 3, application data (traffic information, vehicle information, etc.) received from another in-vehicle communication device 3 or the roadside communication device 2 by the communication control means provided by the layer 7 is acquired and processed. Or an application to transfer is included.

The processes in the layers L1, L2, IVC-RVC, L7 and the process in the application AP are executed by the control unit 23 and the control unit 32.
Further, the control unit 23 and the control unit 32 also execute a security management (SEC) process and a system management (SME) process in FIG.

  Security management (SEC) exchanges information with the layer 7 for security processing via a security service access point (SEC-SAP). Specifically, in security management, the process of securing unsecure application data acquired from layer 7 and returning it to layer 7 and the process of returning secure application data acquired from layer 7 to layer 7 after unsecured Is done.

  System management (SME) exchanges information regarding system management with each of the layers L1, L2, IVC-RVC, and L7 via the layer management entity (LME).

[Configuration of communication packet described in Non-Patent Document 1]
FIG. 6 shows a configuration of communication packets transmitted by the roadside communication device 2 and the in-vehicle communication device 2. The configuration of the communication packet shown in FIG. 6 is basically compliant with Non-Patent Document 1.

The communication packet has a PHY header (physical header) at the head. The PHY header is added before a MAC frame (MPDU; MAC Protocol Data Unit) acquired from the MAC layer by layer 1 (physical layer) of the communication devices 2 and 3 on the transmission side.
The PHY header is read in layer 1 (physical layer) in the communication devices 2 and 3 on the reception side and used for communication control processing in layer 1 on the reception side. Note that the entire communication packet including the PHY header is a PPDU (PHY Protocol Data Unit). A MAC frame (MPDU (MAC Protocol Data Unit)) on the rear side of the PHY header is also a PSDU (PHY Service Data Unit).

  The configuration of the PHY header conforms to IEEE 802.11. Therefore, the PHY header includes a preamble and the like.

Subsequent to the PHY header, a MAC control field (MAC header) and an LLC control field (LLC header) are provided. The MAC control field is added before the LLC frame (LPDU; LLC Protocol Data Unit) acquired from the LLC layer by the MAC layer of the layer 2 of the communication devices 2 and 3 on the transmission side.
The MAC control field is read by the MAC layer of the layer 2 of the communication devices 2 and 3 on the reception side and used for communication control processing in the MAC layer on the reception side.
The LLC frame (LPDU; LLC Protocol Data Unit) behind the MAC control field is also an MSDU (MAC Service Data Unit).

  As shown in FIG. 7A, the MAC control field has a frame control field, a holding period field, a destination address field, a transmission source address field, a radio station identification code field, and a transmission count value field.

  Among the above-mentioned fields included in the MAC control field, the MAC address of the communication devices 2 and 3 as the transmission source is stored in the transmission source address field. The MAC addresses of the communication devices 2 and 3 are mere addresses and do not indicate the type of the communication devices 2 and 3.

  Of the above fields included in the MAC control field, the destination address field stores the destination address. However, in Non-Patent Document 1, only the broadcast address is defined as the destination address. In Non-Patent Document 1, the destination address must be interpreted by all base stations (roadside communication devices) 2 and mobile stations (vehicle communication devices) 3.

Therefore, all the roadside communication devices 2 and in-vehicle communication devices 3 that have detected that the communication packet shown in FIG. 6 is transmitted as a radio signal are used as communication packets addressed to their own devices (own stations) 2 and 3. Will receive as.
However, in the MAC layers of the communication packet receiving side 2 and 3, it is not possible to distinguish whether the received communication packet is a vehicle-to-vehicle communication packet, a road-to-road communication packet, or a road-to-vehicle communication packet.

Of the above fields included in the MAC control field, a wireless station identification code can be stored in the wireless station identification code field. However, according to Non-Patent Document 1, the wireless station identification code is stored in the MAC control field. It will be ignored in the field.
Therefore, the information stored in each field included in the MAC control field does not indicate the type of the communication devices 2 and 3.

  The MAC layers on the receiving side 2 and 3 of the communication packet give the LLC layer an LLC frame (LPDU; MSDU) obtained by removing the MAC control field and the like from the MAC frame (MPDU) of the communication packet that has been successfully received.

Returning to FIG. 6, the LLC control field subsequent to the MAC control field is a field before the IR frame (IPDU; IR Protocol Data Unit) acquired from the IVC-RVC layer by the LLC layer of the layer 2 of the communication devices 2 and 3 on the transmission side. To be added.
The LLC control field is read by the LLC layer of the layer 2 of the communication devices 2 and 3 on the reception side, and used for communication control processing in the LLC layer on the reception side.
An IR frame (IPDU; IR Protocol Data Unit) on the rear side of the LLC control field is also an LSDU (LLC Service Data Unit).

As shown in FIG. 7B, the LLC control field includes a DSAP (Destination Service Access Point) address field, a SSAP (Source Service Access Point) address field, a control field, and a protocol identifier field.
In Non-Patent Document 1, information stored in each field in the LLC control field does not indicate the type of the communication devices 2 and 3.

  The LLC layers on the receiving side 2 and 3 of the communication packet give the IVC-RVC layer an IR frame (IPDU; LSDU) obtained by removing the LLC control field from the LLC frame (LPDU) of the received communication packet.

Returning to FIG. 6, an IR control field (IR header) is provided following the LLC control field. The IR control field is added before the AP frame (APDU; Application Protocol Data Unit) by the IVC-RVC layer of the communication devices 2 and 3 on the transmission side.
The IR control field is read in the IVC-RVC layer of the receiving side communication devices 2 and 3 and used for the communication control processing in the receiving side IVC-RVC layer.
An AP frame (APDU; Application Protocol Data Unit) behind the IR control field is also an ISDU (IR Service Data Unit).

  As shown in FIG. 7C, the IR control field includes a version field, an identification information field, a synchronization information field, a reservation field, a transmission time field, a road-to-vehicle communication period information field, and an extended area field.

The identification information stored in the identification information field is used for identifying the transmission source. The identification information field is a 4-bit field. Of the 4 bits, the first bit is used for identifying the transmission source, and “1” is stored if the transmission source is a base station, and “0” is stored if the transmission source is a mobile station. Therefore, the identification information stored in the identification information field indicates the type of the communication device 2 or 3 as the transmission source.
Of the 4-bit identification information field, bits other than the first bit are reserved for future use in Non-Patent Document 1, and are undefined.

The reserved field (1 bit) in the IR control field is reserved for future use.
Further, the extension field (16 bits) in the IR control field is also reserved for future use.

  According to Non-Patent Document 1, the information stored in each field other than the identification information field in the IR control field does not indicate the type of the communication devices 2 and 3.

  The IVC-RVC layer on the receiving side 2 and 3 of the communication packet gives the layer 7 an AP frame (APDU; ISDU) obtained by removing the IR control field from the IR frame (IPDU) of the received communication packet.

Returning to FIG. 6, following the IR control field, an L7 header is provided. The L7 header is added before the ASDU (Application Service Data Unit) by the layer 7 of the communication devices 2 and 3 on the transmission side.
The layer 7 header is read by the layer 7 of the communication devices 2 and 3 on the reception side and used for communication control processing in the layer 7 on the reception side.

  As shown in FIG. 7D, the layer 7 header has a version field, a security classification information field, a reservation field, and an application related information field.

  Security classification information is stored in the security classification information field (1 bit) of the layer 7 header. The security classification information is information indicating whether or not to pass through the security management SEC when processing the application data. If “0”, it indicates that the security management SEC is not passed. Indicates that it goes through the security management SEC.

The application related information field (8 bits) of the layer 7 header stores application related information that the application AP transmits to the layer 7 on the transmission side, or application related information that the layer 7 transmits to the application on the reception side.
In Non-Patent Document 1, details of application-related information are not defined.

  The reserved field (3 bits) in the layer 7 header is reserved for future use.

  According to Non-Patent Document 1, the information stored in each field of the layer 7 header does not indicate the type of the communication devices 2 and 3.

  When receiving the application data from the application AP, the layer 7 of the transmission side communication devices 2 and 3 receives the application data (unsecured) received from the application AP when receiving an instruction not to pass through the security management SEC. Application data) is handled as ASDU. That is, the layer 7 header is added before the unsecure application data. In this case, “0” indicating that the security management SEC is not passed is stored in the security classification information field of the layer 7 header.

  In the layer 7 of the communication devices 2 and 3 on the receiving side, if “0” indicating that the security management SEC is not passed is stored in the security classification information of the layer 7 header of the received communication packet, the layer 7 from the APDU The part excluding the header is handled as ASDU (unsecure application data). That is, this ASDU (unsecure application data) is given to the application AP.

  On the other hand, when receiving the application data from the application AP, the layer 7 of the communication devices 2 and 3 on the transmitting side receives the instruction to go through the security management SEC and receives the application data ( (Unsecured application data) is passed to the security management SEC via the security service access point SEC-SAP.

In security management SEC, security processing is performed on unsecured application data received from layer 7 to generate secure application data.
The ASDU shown in FIG. 6 indicates secure application data that has been subjected to security processing by the security management SEC. Non-Patent Document 1 does not stipulate the details of secure application data, but secure application data can be composed of a security management header (field for security management) and an application data body.
Information related to security management is stored in the security management header by the security management SEC.
When the application data is secure, the security management header is regarded as a control field in the information included in the ASDU.

The security management SEC returns the secure application data subjected to the security processing to the layer 7 via the security service access point SEC-SAP.
The layer 7 handles secure application data given from the security management SEC as an ASDU. That is, a layer 7 header is added before secure application data (ASDU). In this case, “1” indicating passing through the security management SEC is stored in the security classification information field of the layer 7 header.

  When the layer 7 of the communication devices 2 and 3 on the receiving side stores “1” indicating that the security management SEC is passed in the security classification information of the layer 7 header of the received communication packet, the layer 7 from the APDU The part excluding the header is handled as secure application data. In this case, layer 7 passes secure application data to the security management SEC.

In the security management SEC, processing for converting secure application data given from the layer 7 into unsecure application data is performed.
The security management SEC returns the unsecured application data to the layer 7.
Layer 7 handles the unsecured application data returned from the security management SEC as an ASDU. That is, this ASDU (unsecure application data) is given to the application AP.

Note that in security management SEC, processing (security processing) for converting unsecured application data to secure application data includes processing such as encryption processing and signature processing (provided in Non-Patent Document 1). Absent).
In the security management SEC, the process of converting secure application data to unsecure application data includes processes such as decryption of a cipher and signature verification process (provided in Non-Patent Document 1). Absent).

  Note that the encryption processing for the application data is performed when it is desired to keep the application data secret. For example, the application data for road-to-road communication includes information that is desired to be kept secret from the in-vehicle communication device (mobile station) 3 or a part of the roadside communication devices (base station) 2 such as device maintenance related information. May be. In such a case, application data is encrypted on the transmission side and decrypted on the reception side.

[Enhancement layer and communication packet configuration of Non-Patent Document 2]
FIG. 8 shows an enhancement layer EL that extends the communication function between the application AP and the layer 7 of FIG. This extension layer EL is compliant with the guidelines of Non-Patent Document 2. In the case of the roadside communication device 2 and the in-vehicle communication device 3 that also comply with the guidelines of the nonpatent literature 2 in addition to the standard of the nonpatent literature 1, the processing based on the enhancement layer EL This is executed by the control unit 32 of the in-vehicle communication device 3.
Note that the roadside communication device 2 and the in-vehicle communication device 3 according to the present embodiment basically comply with the guidelines of Non-Patent Document 2 in addition to the standard of Non-Patent Document 1.

  The enhancement layer EL provides a data transmission service to the application AP. The application AP gives application data (traffic information, vehicle information, etc.) stored in the transmitted communication packet to the enhancement layer EL. In order to provide the data transmission service, the enhancement layer EL issues a data transmission request to the lower layer below the layer 7.

Further, the extension layer EL can exchange information for security processing with the security management SEC via the security service access point SEC-SAP, as in the case of the layer 7.
That is, the security management SEC can exchange information with both the layer 7 and the enhancement layer EL.

  FIG. 9 shows a communication packet configuration corresponding to the enhancement layer EL shown in FIG. The communication packet in FIG. 9 corresponds to a packet in which an EL header (EL base station header, EL mobile station header) is added after the L7 header shown in FIG.

The EL header is added before an EL-SDU (EL Service Data Unit) by the enhancement layer EL of the communication devices 2 and 3 on the transmission side.
The EL header is read by the enhancement layer EL of the receiving side communication devices 2 and 3 and used for processing in the receiving side enhancement layer EL.

As shown in FIG. 10A, the EL header (EL base station header) added by the base station (roadside communication device) 2 includes a version field, an EL header type field, an EL security classification information field, and a data related information field. , A division number field, and a reservation field.
As shown in FIG. 10B, the EL header (EL mobile station header) added by the mobile station (vehicle communication device) 3 has a version field, an EL header type field, and an EL security classification information field. .

  The EL header type field is a field in which information for distinguishing between the EL base station header and the EL mobile station header is stored. Therefore, the information stored in the EL header type field indicates the type of the communication device 2 or 3 as the transmission source.

The security classification information field of the EL header is the same as the security classification information field of the layer 7 header.
The extension layer EL is similar to the layer 7 in that it causes the security management SEC to execute processing for converting unsecure application data to secure application data and processing for converting secure application data to unsecure application data. Operate.

Application related information (Data Associated Information) is stored in the data related information field (18 bits) of the EL header.
The reserved field (4 bits) in the EL header (EL base station header) is reserved for future use.

As shown in FIGS. 10C and 10D, BaseStationID (base station ID information), DataSequence (data order information), and DataTotalNumber (data total number information) are provided as application data related information (Data Associated Information). ing.
The base station of the transmission source can be individually identified by BaseStationID (base station ID information).

  According to Non-Patent Document 2, information stored in each field other than the EL header type field in the EL header does not indicate the type of the communication devices 2 and 3.

[Communication Packet of Embodiment]
When the communication packet transmitted by the roadside communication device 2 and the in-vehicle communication device 3 according to the present embodiment conforms only to the standard of Non-Patent Document 1, it basically has the same configuration as the configuration shown in FIG. When conforming to the guideline of Non-Patent Document 2 in addition to the standard of Non-Patent Document 1, it basically has the same configuration as that shown in FIG.

The differences between the communication packets transmitted by the roadside communication device 2 and the in-vehicle communication device 3 of this embodiment described in Non-Patent Documents 1 and 2 are as shown in the following differences 1 and 2.
In the wireless communication system, the roadside communication device 2 and the vehicle-mounted communication device 3 (the roadside communication device 2 and the vehicle-mounted device according to the embodiment) that can transmit communication packets having the differences shown in the following differences 1 and 2 are used. Not only the communication device 3) but also the roadside communication device 2 and the in-vehicle communication device 3 based only on Non-Patent Documents 1 and 2 can be included.

  Since the communication packet transmitted by the roadside communication device 2 and the in-vehicle communication device 3 of the present embodiment basically conforms to Non-Patent Documents 1 and 2, the in-vehicle device conforms only to Non-Patent Documents 1 and 2. Even the communication device 3 (mobile station) and the roadside communication device 2 can receive signals. That is, the in-vehicle communication device 3 (mobile station) and the roadside communication device 2 that comply only with the standards shown in Non-Patent Documents 1 and 2 can also function in the wireless communication system according to the present embodiment.

[Difference 1: Destination address in road-to-road communication]
According to Non-Patent Document 1, only the broadcast address is stored in the destination address field of the MAC control field. However, the control unit 23 of the roadside communication device 2 according to the present embodiment uses the communication packet for the roadside communication device 2. When (roadside road communication packet or roadside road communication packet) is transmitted, a non-broadcast address is set in the destination address field of the MAC control field.

  Specifically, when the control unit 23 (MAC layer) of the roadside communication device 2 or the control unit 32 of the in-vehicle communication device 3 of the present embodiment transmits a communication packet for the roadside communication device, the roadside communication that is the destination A unicast address that specifies the address of the device 2 or a multicast address that specifies a plurality of roadside communication devices 2 as destinations is stored in the destination address field of the MAC control field.

  In this case, the roadside communication device 2 which is the destination determines that the transmitted communication packet is addressed to the own device (own station) because the own device (own station) is designated by the unicast address or the multicast address. Can be received without problems.

On the other hand, even if the roadside communication device 2 and the in-vehicle communication device 3 that are not designated as destinations receive a communication packet, the communication packet can be discarded before processing at a higher layer than the MAC layer. Therefore, the processing load of the in-vehicle communication device 3 that is not designated as the destination can be reduced.
Note that, even if the communication devices 2 and 3 are not designated as destinations, the application data included in the communication packet may be acquired by performing processing in a higher layer than the MAC layer as necessary.

Moreover, in the in-vehicle communication device 3 (the in-vehicle communication device 3 on the premise that all communication packets are transmitted with a broadcast address) based only on Non-Patent Document 1 (and 2), it is transmitted with a non-broadcast address. It is expected that the received communication packet will be rejected as an irregular one storing nonstandard information.
Therefore, the in-vehicle communication device 3 (the in-vehicle communication device 3 on the assumption that all communication packets are transmitted with a broadcast address) based only on Non-Patent Document 1 (and 2) and the road-to-road communication packet are An in-vehicle communication device 3) that is premised on transmission by a cast address or a multicast address can coexist in the same wireless communication system.

  Unicast road-to-road communication can be used, for example, for transmission of individual information (application data) shown in FIG. The individual information refers to information to be transmitted to one specific roadside communication device 2, for example, information detected by the vehicle sensor 6 installed in the vicinity of the first roadside communication device 2. It can be. In this case, the information detected by the vehicle detector 6 is unicasted as individual information from the first roadside communication device 2A to the second roadside communication device 2B located in the vehicle traveling direction.

  Multi-path communication by multicast can be used, for example, for transmission of common information (application data) shown in FIG. The common information refers to information that should be transmitted in common to a plurality of roadside communication devices 2, for example, information indicating the operation of the traffic signal 1 installed in the vicinity of the first roadside communication device 2 is common information. It can be. In this case, information indicating the operation of the traffic signal device 1 is multicast-transmitted as common information from the first roadside communication device 2A to a plurality of roadside communication devices located in four directions.

  In addition, when the control part 23 (MAC layer) of the roadside communication apparatus 2 of this embodiment transmits communication packets (road-to-vehicle communication packets) other than road-to-road communication packets, as shown in Non-Patent Document 1, A broadcast address is set in the destination address field of the MAC control field. In addition, when the communication unit 32 (MAC layer) of the in-vehicle communication device 2 of the present embodiment transmits a communication packet (an inter-vehicle communication packet) other than an inter-vehicle communication packet, as shown in Non-Patent Document 1, A broadcast address is set in the destination address field of the MAC control field.

[Difference 2: Type information of destination communication device]
According to Non-Patent Documents 1 and 2, the information stored in the identification information field of the IR control field (see FIG. 7C) and the EL header type field of the EL header (see FIGS. 10A and 10B). Can be used as information (type information; first information) indicating the types of the communication devices 2 and 3 that are the transmission sources. However, information indicating the type of the destination communication device 2 or 3 is not included.

Therefore, in the communication packet of this embodiment, information (type information; second information) indicating the type of the destination communication devices 2 and 3 is added to a field (control field) other than the application data body.
Since the information indicating the type of the destination communication devices 2 and 3 is included in the communication packet, the communication devices 2 and 3 on the receiving side can transmit the packets transmitted from the road side communication device 2 to other roadside communication devices 2. It is possible to discriminate whether the packet is for the vehicle (road-to-road communication packet or vehicle-to-vehicle communication packet) or the packet for the in-vehicle communication device 3 (road-to-vehicle communication packet or vehicle-to-vehicle communication packet).

  Therefore, even if the vehicle-mounted communication device 2 receives a road-to-road communication packet or a road-to-vehicle communication packet (particularly even when a road-to-road communication packet or a road-to-vehicle communication packet is broadcast). When the communication device type is a roadside communication device (base station) with reference to the second information indicating the type of the destination communication device 2 or 3, before the application data body is read, the inter-road communication packet Can be destroyed.

As described above, the information (second information) indicating the types of the destination communication devices 2 and 3 is the control field (PHY header, MAC control field, LLC control field, IR control field, L7) in the communication packet shown in FIG. Header or security management header).
More specifically, the second information is a field (LC control field, IR control field, or L7 header) read in a layer higher than the MAC layer in the control field, or a processing unit accessed by the higher layer It is provided in a field read in (security management SEC).

By providing the second information in a control field that is read by a higher layer than the MAC layer or a processing unit accessed by the higher layer, the communication devices 2 and 3 on the receiving side discard the received communication packet at the MAC layer. Even if it is not possible (for example, when the destination address of the MAC control field is a broadcast address), it is possible to discard it at a higher layer than the MAC layer.
Specifically, for example, the in-vehicle communication device 3 includes information (first information) indicating the type of the communication device 2 or 3 that is the transmission source of the received communication packet and information indicating the type of the destination communication device 2 or 3 ( 2), if the transmission source is the roadside communication device 2 and the destination is also the roadside communication device 2, it is determined that the received communication packet is an inter-road communication packet. Inter-path communication packets can be discarded.
The in-vehicle communication device 3 also includes information (first information) indicating the type of the communication devices 2 and 3 as the transmission source of the received communication packet, and information (second information) indicating the type of the communication devices 2 and 3 as the destination. When the transmission source is the in-vehicle communication device 3 and the destination is the roadside communication device 2, it is determined that the received communication packet is an inter-road communication packet, and the inter-road communication packet is Can be discarded.
Note that it may be determined whether or not to discard the communication packet in consideration of only the destination communication device type without considering the transmission device type.

Moreover, since the first information and the second information are provided in the control field, the application AP of the receiving side communication devices 2 and 3 reads the received communication packet before reading the application data (application data body). Can be discarded.
Accordingly, application data of communication packets that do not need to be read (for example, application data of road-to-road communication packets or road-to-vehicle communication packets for the vehicle-mounted communication device 3) is read by the application AP of the communication devices 2 and 3 on the receiving side. The processing load caused by processing can be avoided.

More preferably, the second information is provided in at least one of an IR control field, an L7 header, an EL header, and a security management header.
In the IR control field, the L7 header, and the EL header, a field reserved for future use (empty field) is secured in Non-Patent Documents 1 and 2, so the second information is stored in the empty field. Thus, the second information can be added while maintaining consistency with the standards of Non-Patent Documents 1 and 2.
In addition, since the security management header is not defined in Non-Patent Documents 1 and 2, the second information is stored in the security management header, while maintaining consistency with the standards of Non-Patent Documents 1 and 2, Two pieces of information can be added.

When providing the second information in the IR control field, since the extension field (16 bits) and the reserved field (1 bit) of the IR control field are reserved fields, the second information is stored in the extension field or the like. Is preferable (see FIG. 7).
In the identification information field (first bit) of the IR control field, identification information (first information indicating the type of communication device) for identifying whether the transmission source is a base station or a mobile station is stored. Therefore, the IVC-RVC layer on the receiving side reads the first information and the second information, determines whether the received communication packet is an inter-road communication packet or an inter-road communication packet, and Any communication packet or inter-road communication packet can be discarded.
Note that information identifying the transmission source in more detail may be stored in 3 bits other than the first bit of the identification information field.

When the second information is provided in the L7 header, the second information is stored in at least one of the reserved field (3 bits) of the L7 header and the application related information field (8 bits) which is also a reserved field. It is preferable (see FIG. 7). Note that the application-related information field is more preferable because it has a larger area.
The first information may also be provided in at least one of the reserved field (3 bits) and the application-related information field (8 bits) of the L7 header, and the layer 7 is the first from the IVC-RVC layer. Information (identification information of the IR control field) may be acquired. In any case, the layer 7 on the receiving side determines whether the received communication packet is an inter-road communication packet or an inter-road communication packet. If you can, you can discard it.

  Thus, the first information and the second information may be provided in a control field (header) read in the same layer, or may be provided in a control field (header) read in a different layer. .

When the second information is provided in the EL header, it is preferable to store the second information in a reserved field (4 bits) of the EL header.
When the EL header type stored in the EL header type field of the EL header is used as the first information, the reception-side enhancement layer EL refers to the second information stored in the EL header type and reserved field (4 bits). Thus, it is determined whether or not the received communication packet is a road-to-road communication packet or a road-to-vehicle communication packet, and can be discarded if it is a road-to-road communication packet or a road-to-vehicle communication packet.

Further, in the enhancement layer EL, the transmission source base station can be individually identified by BaseStationID (base station ID information).
In road-to-road communication, there is a case in which the roadside communication device 2 on the receiving side only processes application data from a specific roadside communication device 2 and does not want to process application data from other roadside communication devices 2. is there. In this case, the receiving side roadside communication device 2 (the enhancement layer EL thereof) determines whether the received communication packet is a roadside communication packet from a specific roadside communication device 2, BaseStationID (base station ID information). If it is not an inter-road communication packet from a specific roadside communication device 2, it can be discarded.

  When the second information is provided in the security management header, the second information can be stored in an arbitrary field of the security management header. The first information may also be provided in the security management header, or the security management SEC may acquire the first information from the layer 7 or the enhancement layer EL. In any case, the security management SEC on the receiving side can determine whether the received communication packet is an inter-road communication packet or an inter-road communication packet. In addition, when security management determines that it is a road-to-road communication packet or a road-to-vehicle communication packet, the fact is notified to the layer 7 and the road-to-road communication packet in the layer 7 discards the road-to-vehicle communication packet. Can do.

If it is determined in the security management SEC whether or not the received communication packet is a road-to-road communication packet or a vehicle-to-vehicle communication packet, the process shifts to the security management SEC, and inevitably, the security management Processing to convert secure application data to unsecure application data is also performed in SEC.
Therefore, in order to avoid the processing load in the security management SEC, the layer 7 or the extension layer EL on the receiving side is the road-to-road communication packet or the road-to-vehicle communication packet before passing the secure application data to the security management SEC. It is better to determine whether or not.
In other words, in order to avoid the processing load in the security management SEC on the receiving side, it is determined whether the packet is a road-to-road communication packet or a road-to-vehicle communication packet in the enhancement layer, layer 7 or lower layer. It is better to be called.

  From this point of view, it is preferable that the first information and the second information are provided in a control field (LLC control field, IR control field, L7 header, EL header) ahead of the security management header. In this case, the first information and the second information are read in the LLC layer, IVC-RVC layer, layer 7 or enhancement layer EL on the receiving side. Therefore, the packet can be discarded before the security management SEC unsecures the secure application data.

FIG. 12 shows an example of information (including second information) used to distinguish between roadside communication or roadside road communication and other communication.
The information illustrated in FIG. 12 includes destination communication device type (4 bits), which is second information, and information type / destination ID information (4 bits).
Since the information shown in FIG. 12 has a total of 8 bits, it is suitable as information provided in the application related information field (8 bits) of the layer 7 or the extended area field (16 bits) of the IR control field. Further, the information shown in FIG. 12 may be provided in the security management header.

  The destination communication device type has a “road” bit, a “car” bit, a “walk” bit, and a “reservation” bit. The “road” bit indicates whether or not the destination communication device type is a roadside communication device (base station) 2, and the “car” bit indicates that the destination communication device type is an in-vehicle communication device among mobile stations. The “walk” bit indicates whether the destination communication device type is a pedestrian communication device carried by a pedestrian among mobile stations, and the “reservation” bit is for future use. Are reserved bits.

When “1” is stored in each bit, it indicates that the communication device indicated by the bit is included as the destination. When “0” is stored, the communication device indicated by the bit is included in the destination. Indicates no.
Note that the second information is not 4 bits as shown in FIG. 12, but is 1 bit if it is information only for distinguishing between the base station (roadside communication device) and the mobile station (vehicle communication device). If there is enough.

  Information such as the information type / destination ID shown in FIG. 12 is the ID of the roadside communication device 2 that is the destination in the case of road-to-road communication or road-to-vehicle communication, or a communication mode other than road-to-road communication and road-to-road communication. Indicates the information type of application data (or other data) transmitted in (road-to-vehicle communication, road-to-vehicle communication, vehicle-to-vehicle communication, vehicle-to-vehicle communication, vehicle-to-vehicle communication).

The information such as the information type / destination ID has a “type / ID” bit and content bits (b2, b1, b0). The “type / ID” bit is a flag indicating whether the content bit indicates the information type or the ID of the destination roadside communication device 2.
In the content bits (b2 to b0), the ID of the roadside communication device 2 as the destination or information indicating the information type is stored.

  For example, when the ID of the roadside communication device 2 that is the destination is stored in the application-related information field of the L7 header or the extension area field of the IR control field, the layer 7 or IVC-RVC layer on the receiving side becomes the destination. The destination roadside communication device can be individually identified by the ID of the roadside communication device 2.

As the information type stored in the content bits (b2 to b0), as shown in FIG. 12, for example, information for security information update guidance, information for informing that an emergency vehicle is being activated, tsunami generation It is information which notifies disaster information.
The information stored in the content bits (b2 to b0) may be information processed by the reception side separately from the application data, or may be information indicating the type of application data.

  When the information type is stored in, for example, the application related information field of the L7 header or the extension field of the IR control field, the layer 7 or IVC-RVC can be obtained on the receiving side even if the application AP does not acquire the application data. In the layer, the information type can be grasped quickly.

FIG. 13 shows another example of information used for distinguishing between road-to-road communication or road-to-vehicle communication and other communications.
The information shown in FIG. 13 includes a source communication device type (2 bits) that is first information, a destination communication device type (4 bits) that is second information, and a data type (2 bits). Yes.
Since the information shown in FIG. 13 is 8 bits in total, it is suitable as information provided in the application-related information field (8 bits) of the layer 7 or the extended area field (16 bits) of the IR control field. Further, the information shown in FIG. 13 may be provided in the security management header.

When the source communication device type shown in FIG. 13 is “00”, it indicates that the communication device type of the transmission source is the roadside communication device (base station) 2, and when “01”, the communication device type of the transmission source Indicates that it is the in-vehicle communication device 3, and when it is "10", it indicates that the communication device type of the transmission source is a pedestrian communication device. “11” is a reservation for the future.
The destination communication device type shown in FIG. 13 is the same as the destination communication device type shown in FIG.

  The data type shown in FIG. 13 indicates whether it is normal information or emergency information (high priority information). If the data type is “00”, it indicates normal information, and if it is “01”, it indicates emergency information.

FIG. 14 shows another example of information used for distinguishing between road-to-road communication or road-to-vehicle communication and other communications.
The information shown in FIG. 14 includes a source communication device type (2 bits) that is first information, a destination communication device type (3 bits) that is second information, and a data type (3 bits). Yes.
Since the information shown in FIG. 14 is 8 bits in total, it is suitable as information provided in the application related information field (8 bits) of the layer 7 or the extension area field (16 bits) of the IR control field. Further, the information shown in FIG. 14 may be provided in the security management header.

The source communication device type shown in FIG. 14 is the same as the transmission source communication device type shown in FIG.
The destination communication device information illustrated in FIG. 14 includes a “route” bit, an “all terminals” bit, and a “reservation” bit. The “road” bit indicates whether or not the destination communication device type is the roadside communication device (base station) 2. If “1” is stored in the “road” bit, the roadside communication device 2 is set as the destination. included. If “1” is stored in the “all terminals” bit, all terminals including roadside communication devices, in-vehicle communication devices, and pedestrian communication devices become destinations. The “reserved” bit is a reserved bit for the future.

  The data type shown in FIG. 14 indicates whether it is normal information or emergency information (high priority information). If the data type is “000”, it indicates normal information, and if it is “001”, it indicates emergency information.

FIG. 15 shows another example of information used for distinguishing between road-to-road communication or road-to-vehicle communication and other communications.
The information shown in FIG. 15 includes a source communication device type (2 bits) that is first information, a destination communication device type (3 bits) that is second information, and a data type (3 bits). Yes.
Since the information shown in FIG. 14 is 8 bits in total, it is suitable as information provided in the application related information field (8 bits) of the layer 7 or the extension area field (16 bits) of the IR control field. Further, the information shown in FIG. 15 may be provided in the security management header.

  The source communication device type and the destination communication device type shown in FIG. 15 are the same as the transmission source communication device type and the destination communication device type shown in FIG.

  The data type shown in FIG. 15 indicates the type of information transmitted as application data. The types of data (information) include “safe driving support” information, “vehicle information”, “maintenance information”, “security information update guidance” information, “emergency driving” information, “walking” Information on "person information" and "tsunami occurrence".

With respect to the present invention, the embodiments disclosed this time should be considered as illustrative in all points and not restrictive. 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.
For example, the first information and the second information do not need to be provided as distinguishable as information, and, for example, a plurality of communication forms including a road-to-road communication, a road-to-vehicle communication, and a vehicle-to-vehicle communication (transmission source type and If the information for distinguishing the type of the communication form distinguished by the destination type) is provided, this corresponds to the provision of both the first information and the second information.

1 Traffic signal 2 Roadside communication equipment (base station)
3 In-vehicle communication device (mobile station)
4 Central Device 5 Vehicle 6 Roadside Sensor 7 Wired Communication Line 23 Control Unit 24 Storage Unit 32 Control Unit 33 Storage Unit

Claims (13)

A communication device capable of transmitting communication packets for a base station,
The communication packet transmitted by the communication device includes type information including information indicating a destination communication device type,
The type information is a control field of the communication packet, and is provided in a control field read by a higher layer than the MAC layer or a processing unit accessed by the upper layer on the communication packet receiving side. A communication device. The communication device according to claim 1, wherein the type information is information capable of identifying whether the communication device is a base station or a mobile station. The communication device is used in a wireless communication system that can include a mobile station compliant with a standard in which only a broadcast address is defined as a destination address of a communication packet.
The communication according to claim 1 or 2, wherein when transmitting a communication packet for a base station, an address that is a non-broadcast address and is destined for the base station is set as a destination address in a MAC control field of the communication packet. Machine. The communication device according to any one of claims 1 to 3, wherein the type information is provided in at least one of the following a) to d).
a) IR control field defined in 700 MHz band intelligent road traffic system standard (ARIB STD-T109) b) Layer 7 header defined in 700 MHz band intelligent road traffic system standard (ARIB STD-T109) c) 700 MHz band intelligent road EL header specified in the Transport System Extended Function Guidelines (ITS FORM RC-010) d) Field for security management of application data stored in communication packets The type information is provided in a control field that is read before performing processing for converting secure application data subjected to security processing to unsecure application data on the receiving side of the communication packet. 5. The communication device according to any one of 4. The communication device according to any one of claims 1 to 5, wherein the communication packet is further provided with information indicating a communication device type of a transmission source as the type information. A communication device used in a wireless communication system that can include a mobile station compliant with a standard in which only a broadcast address is defined as a destination address of a communication packet,
When transmitting a communication packet for a base station, a communication device that sets a non-broadcast address and an address to which the base station is a destination as a destination address in a MAC control field of the communication packet. The communication device according to claim 1, wherein the communication device is a base station. The communication device according to any one of claims 1 to 7, wherein the communication device is a mobile station. A mobile station that performs wireless communication with a base station and another mobile station,
By reading information indicating the destination communication device type from the received communication packet, it is determined whether or not the communication packet is a communication packet transmitted to the base station. Is configured to discard the communication packet,
The information is a control field of the communication packet, and is provided in a control field read by a higher layer than the MAC layer or a processing unit accessed by the upper layer in the mobile station. . A wireless communication system including a base station and a mobile station that perform wireless communication,
The base station or the mobile station is configured to transmit a communication packet including information indicating a destination communication device type,
The mobile station reads the information from the received communication packet to identify whether the communication packet is a communication packet transmitted to the base station, and the communication packet is transmitted to the base station. If it is a transmitted communication packet, the communication packet is configured to be discarded,
The information is a control field of the communication packet, and is provided in a control field read by a higher layer than the MAC layer or a processing unit accessed by the upper layer on the receiving side of the communication packet. Wireless communication system. A computer program executed by a computer provided in a communication device capable of transmitting a communication packet for a base station,
Configured to cause the computer to execute a process of generating a communication packet including information indicating a destination communication device type,
The information is a control field of the communication packet, and is provided in a control field read by a higher layer than the MAC layer or a processing unit accessed by the upper layer on the receiving side of the communication packet. Computer program. A computer program executed by a computer provided in a mobile station that performs wireless communication with a base station and another mobile station,
A process of identifying whether the communication packet is a communication packet transmitted to a base station by reading information indicating a destination communication device type from the received communication packet; and
When the communication packet is a communication packet transmitted to a base station, a process of discarding the communication packet;
Configured to cause the computer to execute
The information is provided in a control field of the communication packet, which is provided in a control field read by a higher layer than the MAC layer or a processing unit accessed by the upper layer in the mobile station. .

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