JP5194296B2 - WIRELESS NETWORK, WIRELESS DEVICE USED FOR THE SAME, AND MOBILE BODY WITH THE WIRELESS DEVICE - Google Patents

Description

  The present invention relates to a wireless network, a wireless device used therefor, and a mobile body including the wireless device, and more particularly to a wireless network used for vehicle-to-vehicle communication, a wireless device used therefor, and a mobile body including the wireless device. It is.

  In a wireless network that performs wireless communication between vehicles, position information is used in several places. Each wireless device in the wireless network needs position information of surrounding wireless devices for a routing protocol for performing a route search based on the location information or for safe driving of the vehicle.

  Conventionally, a method for distributing position information of each vehicle on a wireless network at a cycle according to the speed of the vehicle has been proposed (Non-Patent Document 1). By using this method, it is possible to reduce location information distribution overhead in a multi-hop wireless network.

  In addition, a routing protocol that does not require location exchange of peripheral terminals has been proposed (Non-Patent Document 2). This protocol employs a technique in which positional information between a transmitting terminal and a receiving terminal is included in the head of the packet and the packet is transferred without transmitting a Hello message, and is effective for unicast communication.

Further, in Non-Patent Document 2, it is proposed to significantly reduce overhead when a broadcast packet is transferred using a technique called MPR (Multi-Point-Relay).
S. Basagni, I. Chlamtac, VR Syrotiuk, and BA Woodward, “A distance routing effect algorithm for mobility (DREAM),” MobiCom'98, pp.76-84, 1998. Holger Fusler, Jorg Widmer, Michael Kasemann, Martin Mauve, and Hannes Hartenstein, “Beaconless position-based routing for mobile ad-hoc networks, Ad Hoc Networks,” Vol. No.1, pp.351-369, 2003.

  However, the conventional method of exchanging location information mainly considers multi-hop transfer efficiency and does not assume application to safe driving etc. in inter-vehicle communication. There is a problem that it is difficult to efficiently exchange position information.

  Further, the conventional method has a problem that it is difficult to control overhead when exchanging position information and to ensure the accuracy of position information.

  Accordingly, the present invention has been made to solve such a problem, and an object thereof is to provide a wireless network in which each wireless device can efficiently exchange position information with a peripheral terminal.

  Another object of the present invention is to provide a wireless network that can control overhead and exchange position information with high accuracy.

  Furthermore, another object of the present invention is to provide a wireless device used in a wireless network in which each wireless device can efficiently exchange position information with a peripheral terminal.

  Furthermore, another object of the present invention is to provide a wireless device used in a wireless network that can control overhead and exchange position information with high accuracy.

  Furthermore, another object of the present invention is to provide a mobile unit including a wireless device used in a wireless network in which each wireless device can efficiently exchange position information with a peripheral terminal.

  Furthermore, another object of the present invention is to provide a mobile unit including a wireless device used in a wireless network that controls overhead and can exchange highly accurate position information.

  According to the present invention, the wireless network is a wireless network that performs wireless communication between moving bodies, and includes the first and second wireless devices. The first wireless device is mounted on the first moving body, and when the error between the actual position and the predicted position of the first moving body is equal to or less than a threshold value, the position information of the first moving body is transmitted in the wireless network. The transmission is performed with a second transmission cycle longer than the first transmission cycle, which is a transmission cycle of a periodically transmitted message. The second radio apparatus is mounted on a second mobile body adjacent to the first mobile body, and receives position information transmitted from the first radio apparatus.

  Preferably, the first radio apparatus predicts the position of the first moving body for each first transmission period based on the position information of the first moving body acquired at the first transmission timing, and the prediction When the error between the predicted position and the actual position of the first moving body acquired at each first transmission cycle is equal to or less than the threshold, the first position information indicating the actual position of the first moving body Transmission at each transmission cycle is stopped, and position information indicating the actual position of the first moving body is transmitted at a second transmission timing after the second transmission cycle has elapsed from the first transmission timing.

  Preferably, the second radio apparatus has the first mobile unit for each first transmission period based on the position information of the first mobile unit transmitted from the first radio apparatus at the first transmission timing. Predict location.

  Preferably, the first wireless device transmits position information indicating an actual position of the first moving body in the first transmission cycle when the error is larger than the threshold value.

  Preferably, the threshold is determined by the speed of the first moving body.

  Preferably, when the second wireless device receives the position information from the first wireless device, the second wireless device sets a timer period longer than the second transmission cycle, and the position from the first wireless device is within the set timer period. When no information is received, a transmission request for position information is transmitted to the first wireless device. In response to the transmission request, the first wireless device transmits the position information to the second wireless device at a timing with relatively little interference.

  Preferably, when the speed of the first moving body is slower than the reference speed, the first wireless device sets the second transmission cycle to be relatively long and transmits the position information of the first moving body, When the speed of the first moving body is equal to or higher than the reference speed, the second transmission cycle is relatively shortened in a range longer than the first transmission cycle, and the position information of the first moving body is transmitted.

  Preferably, the first radio apparatus transmits an adjustment parameter for adjusting the length of the second transmission cycle together with the position information, and the second radio apparatus receives the adjustment parameter and receives the received adjustment parameter. Is used to adjust the timer period for requesting transmission of position information.

  Preferably, the second radio apparatus transmits the position information of the first moving body received from the first radio apparatus together with the position information of the second moving body while avoiding redundant transmission.

  Preferably, the second wireless device includes the first mobile body and the second mobile device based on the position information of the second mobile body and the position information of the first mobile body received from the first wireless device. The distance to the moving object is calculated, and when the calculated distance is less than the safe distance, a danger forecast message is created and transmitted to the first wireless device.

  According to the present invention, the wireless device includes any one of the first and second wireless devices according to any one of claims 1 to 10.

  Furthermore, according to the present invention, the moving body includes the second wireless device and the speed reducer. The second wireless device is mounted on another mobile unit with a second transmission cycle that is longer than the first transmission cycle, which is a transmission cycle of messages periodically transmitted in a wireless network that performs wireless communication between the mobile units. The position information of the other moving body is received from the first wireless device that has been acquired, the position information of the moving body is acquired, and the other information is obtained based on the position information of the other moving body and the position information of the moving body The distance between the moving body and the moving body is calculated, and a brake signal is output when the calculated distance falls below the safety distance. When the deceleration device receives a brake signal from the second wireless device, the deceleration device executes deceleration processing.

  In the present invention, the first wireless device transmits the position information of the first mobile unit at a transmission cycle longer than a transmission cycle of a message periodically transmitted in the wireless network, and the second wireless device The position information transmitted from the first wireless device is received.

  Therefore, according to the present invention, it is possible to exchange the position information more efficiently than when the position information is included in a message periodically transmitted in the wireless network.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic diagram of a wireless network according to an embodiment of the present invention. The radio network 100 according to the embodiment of the present invention is a network that performs route search according to, for example, OLSR (Optimized Link State Routing), and performs radio communication according to a CDMA (Code Division Multiple Access) system. The wireless network 100 includes wireless devices M1 to M30. Wireless devices M1 to M30 are mounted on vehicles C1 to C30, respectively, and autonomously configure a wireless network.

  Each of the wireless devices M1 to M30 efficiently exchanges position information of the vehicle (any one of the vehicles C1 to C30) on which the wireless device M1 to M30 is mounted. In addition, the wireless devices M1 to M30 exchange accurate position information of the vehicle (any one of the vehicles C1 to C30) on which the wireless devices M1 to M30 are mounted by controlling overhead.

  FIG. 2 is a schematic block diagram showing the configuration of the wireless device M1 shown in FIG. The wireless device M1 includes an antenna 1, a communication control unit 2, a GPS (Global Positioning System) receiver 3, and an INS (Internal Navigation System) device 4.

  The antenna 1 receives a packet from another wireless device via the wireless communication space, and outputs the received packet to the communication control unit 2. Further, the antenna 1 transmits the packet received from the communication control unit 2 to another wireless device via the wireless communication space.

  The communication control unit 2 receives a GPS signal from the GPS receiver 3, and acquires the position of the vehicle on which the wireless device M1 is mounted by a known method based on the received GPS signal. Further, the communication control unit 2 receives the INS signal from the INS device 4 and acquires the speed and moving direction of the vehicle on which the wireless device M1 is mounted based on the received INS signal.

  In the wireless network 100, when the transmission period of the Hello message used for exchanging route information is T, the communication control unit 2 has a case where the error between the actual position of the vehicle on which it is mounted and the predicted position is less than or equal to the threshold value. The acquired position, speed, and moving direction are transmitted to another wireless device at a transmission cycle of N × T (N is, for example, 4) via the antenna 1, and the vehicle on which the other wireless device is mounted is transmitted. The position, speed, and direction of movement are received at a cycle of N × T. In this way, the communication control unit 2 exchanges the position, speed, and moving direction of different vehicles.

  And the communication control part 2 manages the information of the position, speed | velocity | rate, and moving direction which communicated with the other radio | wireless apparatus by the method mentioned later, Based on the information of the managed position, speed | velocity | rate, and moving direction, The distance between the vehicle C1 on which the vehicle is mounted and the vehicle adjacent to the vehicle C1 is calculated, and when the calculated distance is less than the safety distance, a danger forecast message is created and transmitted.

  In addition, when the communication control unit 2 receives the danger forecast message from another wireless device, the communication control unit 2 outputs the danger forecast message to the deceleration device of the vehicle on which the wireless device M1 is mounted.

  The GPS receiver 3 receives a GPS signal from a GPS satellite and outputs the received GPS signal to the communication control unit 2.

  The INS device 4 detects the INS signal and outputs the detected INS signal to the communication control unit 2.

  The communication control unit 2 includes a wireless interface module 21, an IP module 22, a GPS module 23, and an INS module 24. The wireless interface module 21 belongs to the physical layer. The wireless interface module 21 transmits a packet to another wireless device via the antenna 1 and receives a packet from the other wireless device via the antenna 1.

The IP module 22 belongs to the network layer, receives the position of the vehicle on which the wireless device M1 is mounted from the GPS module 23, and receives the moving direction and speed of the vehicle on which the wireless device M1 is mounted from the INS module 24. Then, the IP module 22 stores the position information P _Self consisting of the received position, speed and moving direction in a position information table described later.

The IP module 22 receives position information P _{Other including} the position, speed, and moving direction of the vehicle on which the other wireless device is mounted via the antenna 1 and the wireless interface module 21 from the other wireless device. Then, the IP module 22 stores the received position information P _Other in the position information table.

Furthermore, the IP module 22 transmits the position information P _Self and P _Other stored in the position information table to other wireless devices via the wireless interface module 21 and the antenna 1 with a transmission cycle of N × T or more.

The IP module 22 calculates the distance between the vehicle C1 on which the wireless device M1 is mounted and the vehicle adjacent to the vehicle C1 based on the exchanged position information P _Self and P _Other , and the calculated distance is safe. Create and send a danger forecast message when below the distance.

  Furthermore, when receiving the danger forecast message from another wireless device, the IP module 22 generates a brake signal for decelerating the speed of the vehicle C1 and outputs the brake signal to the deceleration device of the vehicle C1.

  The GPS module 23 receives a GPS signal from the GPS receiver 3, detects the position of the vehicle on which the wireless device M1 is mounted by a known method based on the received GPS signal, and the detected position is the IP module. 22 to output.

  The INS module 24 detects the moving direction and speed of the vehicle C1 on which the wireless device M1 is mounted based on the INS signal received from the INS device 4, and outputs the detected moving direction and speed to the IP module 22.

  Note that each of the wireless devices M2 to M30 illustrated in FIG. 1 has the same configuration as the wireless device M1 illustrated in FIG.

  FIG. 3 is a functional block diagram of the IP module 22 shown in FIG. The IP module 22 includes a storage unit 221, a calculation unit 222, a control unit 223, and an information generation unit 224.

  The storage unit 221 stores a position information table that stores the position information of the vehicle on which the vehicle is mounted and the vehicles existing around the vehicle.

  The computing means 222 computes the distance L between the vehicle C1 on which the wireless device M1 is mounted and the vehicle adjacent to the vehicle C1 in response to the instruction signal INST1 from the control means 223, and the computed distance L is calculated. Output to the control means 223.

Control means 223 receives from the GPS module 23 at the position _{P C1 = <x C1, y} C1> the time _{T 1} of the vehicle C1 to the wireless device M1 is mounted, the time the moving direction alpha _C1 and velocity _{V C1} of the vehicle C1 It received from the INS module 24 at T _1. Then, the control means 223 stores the position information <P _C1 , V _C1 , α _C1 , T ₁ > composed of the received position P _C1 , moving direction α _C1 and speed V _C1 in the position information table.

Further, the control means 223 obtains the position information <P _Cj , V _Cj , α _Cj , T ₂ > of the vehicle Cj from the wireless device Mj mounted on the vehicle Cj (j = any of C2 to C30) other than the vehicle C1. The received position information <P _Cj , V _Cj , α _Cj , T ₂ > is stored in the position information table.

  The control means 223 has a built-in timer (not shown). When the transmission period T is measured by the timer, the control means 223 refers to the position information table based on the position information of the vehicle C1 acquired at the timing T1. The position of the vehicle C1 at the timing T2 (timing after a period KT (K is an integer satisfying 0 <K <N) from the timing T1) is predicted by a method described later.

  Then, the control unit 223 calculates an error ΔPS between the position information of the vehicle C1 actually measured at the timing T2 and the predicted position information, and the calculated error ΔPS is smaller than a threshold value (= 0.1 V × T). It is determined whether or not. As described above, the control unit 223 determines whether or not the error ΔPS is smaller than the threshold value (= 0.1V × T) determined by the vehicle speed V.

  Then, when the error ΔPS is equal to or greater than the threshold value (= 0.1 V × T), the control unit 223 generates an instruction signal INST2 for instructing transmission of the position information message and outputs the instruction signal INST2 to the information generation unit 224.

  On the other hand, the control unit 223 does not output the instruction signal INST2 to the information generation unit 224 when the error ΔPS is smaller than the threshold value (= 0.1 V × T).

  Note that the control means 223 predicts the position of the vehicle C1 and determines whether or not the error ΔPS is smaller than a threshold value (= 0.1 V × T) every transmission cycle T.

  Further, the control means 223 generates an instruction signal INST2 and outputs the instruction signal INST2 to the information generation means 224 at the timing T3 when the cycle N × T has elapsed from the timing T1 when the position information of the vehicle C1 is transmitted.

Further, when receiving the position information <P _Cj , V _Cj , α _Cj , T ₂ > from another wireless device, the control unit 223 sets a timer period of (N + 0.5) × T and sets the set timer When new position information is not received from another wireless device within the period, an instruction signal INST3 for transmitting the position information transmission request message ARQ is generated and output to the information generating means 224.

  Further, when the control means 223 refers to the position information table stored in the storage means 221 and detects a vehicle traveling before and after the vehicle C1 on which the control means 221 is mounted, the control means 223 determines the relationship between the detected vehicle and the vehicle C1. An instruction signal INST1 for calculating the distance between them is generated and output to the calculation means 222. When the control unit 223 receives the distance L from the calculation unit 222, the control unit 223 determines whether or not the received distance L is shorter than the safe distance. When the control unit 223 determines that the distance L is shorter than the safe distance, An instruction signal INST4 for instructing generation of a message is generated and output to the information generation means 224. The control unit 223 does not output the instruction signal INST4 to the information generation unit 224 when the distance L is equal to or greater than the safe distance.

  Furthermore, when receiving the danger forecast message from another wireless device, the control means 223 generates a brake signal for reducing the speed of the vehicle C1 on which the wireless device M1 is mounted, and outputs the brake signal to the reduction device.

  When receiving the instruction signal INST2 from the control unit 223, the information generation unit 224 generates and broadcasts a location information message by a method described later.

  Further, upon receiving the instruction signal INST3 from the control unit 223, the information generation unit 224 generates and transmits a transmission request message ARQ.

  Further, when the situation generation unit 224 receives the instruction signal INST4 from the control unit 223, the situation generation unit 224 generates and transmits a danger forecast message.

  FIG. 4 is a configuration diagram of a position information table stored in the storage unit 221 shown in FIG. The location information table TBL includes a terminal number, terminal location information, a transmission terminal number, transmission completion, and peripheral terminals. The terminal number, terminal location information, transmission terminal number, transmitted, and peripheral terminal are associated with each other.

  A terminal number consists of the number of the radio | wireless apparatus mounted in the vehicle which has terminal position information. The terminal position information includes position information of a vehicle on which a wireless device represented by a terminal number is mounted.

  The transmission terminal number consists of the number of the wireless device that transmitted the terminal location information. “Transmitted” includes either “YES” indicating that the terminal position information has been transmitted or “NO” indicating that the terminal position information has not been transmitted.

  When the wireless device represented by the transmitting terminal number directly transmits the terminal location information to the wireless device holding the location information table TBL, the peripheral terminal stores “YES” and the wireless device represented by the transmitting terminal number When terminal location information of a wireless device other than itself is transmitted to a wireless device that holds the location information table TBL, “NO” is stored. That is, the peripheral terminal stores “YES” when the terminal number and the transmitting terminal number match, and stores “NO” when the terminal number and the transmitting terminal number do not match.

  FIG. 5 is a diagram showing a format of the location information message. The location information message PSM includes a header HED and messages MS1 and MS2. The header HED includes a transmission source SRC of the location information message PSM and a transmission destination DST. The transmission source SRC is composed of the identification number Self ID of the wireless device that creates the location information message PSM. The transmission destination DST is composed of BROADCAST indicating that the position information message PSM is broadcast.

  The message MS1 includes position information Self position of a vehicle on which a wireless device that generates the position information message PSM is mounted, and a transmission interval. The position information Self position includes an identification number ID of a wireless device that generates the position information message PSM and position information <P, V, α, T> of the vehicle on which the wireless device that generates the position information message PSM is mounted. . The position information <P, V, α, T> is associated with the identification number ID of the wireless device. The transmission interval is N × T.

The message MS2 includes the number # neighbor = M of wireless devices adjacent to the wireless device that generates the location information message PSM, the identification numbers ID ₁ and ID _{2 of} the wireless devices adjacent to the wireless device that generates the location information message PSM, From the position information <P ₁ , V ₁ , α ₁ , T ₁ >, <P ₂ , V ₂ , α ₂ , T ₂ > of the vehicle adjacent to the vehicle on which the wireless device for creating the position information message PSM is mounted. Become. Note that the message MS2 is optional, and is included in the position information message PSM when the wireless device M1 that creates the position information message PSM has the position information of the vehicle C1 and the position information of the vehicle adjacent to the vehicle C1. .

  A method for transmitting the position information message PSM of each vehicle will be described in detail. FIG. 6 is a diagram for explaining a transmission method of the location information message PSM. FIG. 7 is a diagram illustrating an example of the position information table TBL.

The vehicles C1 to C3 are traveling in the same direction, the vehicle C2 is a succeeding vehicle of the vehicle C1, and the vehicle C3 is a succeeding vehicle of the vehicle C2 (see (a) of FIG. 6). In such a situation, the wireless devices M1 to M3 mounted on the vehicles C1 to C3 respectively have the positional information of the vehicles C1 to C3 <P _M1 , V _M1 , α at the timing T1 (= t1) by the method described above. _{M1, T 1>, <P} M2, V M2, α M2, T 1>, <P M3, V M3, acquires α _{M3, T 1>,} the acquired position information _{<P M1, V M1, α M1, T 1>, <P} M2, V M2, α M2, T 1>, the _{<P M3, V M3, α} M3, T 1 respectively> position information table TBL-M1-1~TBL-M3-1 Store (see FIG. 7).

  FIG. 8 is a diagram illustrating an example of the location information message PSM. FIG. 9 is a diagram showing another example of the position information table TBL.

In the situation where the position information tables TBL-M1-1 to TBL-M3-1 are created in the wireless devices M1 to M3, respectively, the control means 223 of the wireless device M2 receives the instruction signal INST2 for generating the position information message PSM. The information is generated and output to the information generation means 224. Then, the information generation unit 224 of the wireless device M2 stores the terminal number M2 of the wireless device M2 and the transmission destination DST = BROADCAST in the header HED in response to the instruction signal INST2 from the control unit 223, and is stored in the storage unit 221. Message of location information <P _M2 , V _M2 , α _M2 , T ₁ >, terminal number M2 and transmission interval N × T (= 4T) in the location information table TBL-M2-1 (see FIG. 7B) The location information message PSM-1 stored in the MS 1 is generated (see FIG. 8).

  Then, the information generation unit 224 of the wireless device M2 broadcasts the location information message PSM-1 via the wireless interface module 21 and the antenna 1. Thereafter, the control unit 223 of the wireless device M2 changes “NO” in the position information table TBL-M2-1 to “YES” and changes the position information table TBL-M2-1 to the position information table TBL-M2-2. (Refer to (b) of FIG. 9).

  The wireless device M1 mounted on the vehicle C1 traveling immediately before the vehicle C2 and the wireless device M3 mounted on the vehicle C3 traveling immediately after the vehicle C2 receive the position information message PSM-1 transmitted from the wireless device M2. To do.

Then, the control means 223 of the wireless device M1 detects SRC = M2 stored in the header HED of the location information message PSM-1 and detects that the location information message PSM-1 is transmitted from the radio device M2. Further, the control means 223 of the wireless device M1 transmits the terminal number M2, the position information <P _M2 , V _M2 , α _M2 , T ₁ > and the transmission interval NT (= 4T) stored in the message MS1 of the position information message PSM-1. ) Is detected.

Then, the control unit 223 of the wireless device M1 reads the position information table TBL-M1-1 (see (a) of FIG. 7) stored in the storage unit 221 and stores the read position information table TBL-M1-1. storing the _{ID M2} in the column of the terminal number, and stores the position information _{<P M2, V M2, α} M2, T 1> to the column of the terminal position information, and stores the _{ID M2} in the column of the transmission terminal number, sent “NO” is stored in the column of “No.”, and the terminal number ID _M2 and the transmission terminal number ID _M2 match, so “YES” is stored in the column of the peripheral terminal, and the position information table TBL-M1-1 is stored in the position information table TBL. Update to M1-2 (see FIG. 9A).

  The control unit 223 of the wireless device M3 also performs the same operation as the control unit 223 of the wireless device M1, and based on the position information message PSM-1, the position information table TBL-M3-1 (in FIG. 7) stored in the storage unit 221. (See (c)) is updated to the position information table TBL-M3-2 (see (c) in FIG. 9).

  FIG. 10 is a diagram showing still another example of the position information table TBL. FIG. 11 is a diagram illustrating another example of the position information message PSM.

When the period T has elapsed from the timing T1 when the wireless device M2 transmits the position information message PSM-1, the vehicles C1 to C3 move to the positions shown in FIG. And the control means 223 of the radio | wireless apparatuses M1-M3 in timing T2 (= t2), respectively, positional information <P _M1 , V _M1 , α _M1 , T ₂ >, <P _M2 , V _{M2 of the} vehicles C1-C3. , Α _M2 , T ₂ >, <P _M3 , V _M3 , α _M3 , T ₂ >.

Then, the control unit 223 of the wireless device M2 obtains the position information <P _M2 , V _M2 , α _M2 , T ₁ > acquired at the timing T1 from the position information table TBL-M2-2 (see (b) of FIG. 9). Based on the read position information <P _M2 , V _M2 , α _M2 , T ₁ >, the position of the vehicle C2 at the timing T2 is predicted.

More specifically, the control unit 223 of the wireless device M2 substitutes P _M2 = (x _T1 , y _T1 ), α _M2 = α _T1 , V _M2 = V _T1 into the following equations (1) and (2). _Thus , the position ( _{xT2_P} , _{yT2_P} ) of the vehicle C2 at the timing T2 is predicted.

_{x T2_P = x T1 + V T1} cos (α T1) (T 2 -T 1) ··· (1)
_{y T2_P = y T1 + V T1} sin (α T1) (T 2 -T 1) ··· (2)

The control unit 223 of the wireless device M2 then predicts the predicted position P _{M2_P} = (x _{T2_P} , y _{T2_P} ) of the predicted vehicle C2 and the actual position P _M2 = (x _T2 , y of the vehicle C2 acquired at the timing T2. _T2) error between DerutaPS ₌ calculates the _{(x T2_P -x T2, y T2_P} -y T2). Thereafter, the control unit 223 of the wireless device M2 determines whether or not the calculated error ΔPS is equal to or less than a threshold value (= 0.1 V _T2 ) × T.

Then, when the error ΔPS is larger than the threshold value (= 0.1 V _T2 ) × T, the control unit 223 of the wireless device M2 obtains the position information <P _M2 , V _M2 , α _M2 , T ₂ > acquired at the timing T2. The information is stored in the position information table TBL-M2-2 (see FIG. 9B) and the position information table TBL-M2-2 is updated to the position information table TBL-M2-3 (see FIG. 10B). . Thereafter, the control unit 223 of the wireless device M2 generates an instruction signal INST2 for transmitting the position information <P _M2 , V _M2 , α _M2 , T ₂ > and outputs the instruction signal INST ₂ to the information generation unit 224.

The information generation unit 224 of the wireless device M2 reads the position information table TBL-M2-3 stored in the storage unit 221 in response to the instruction signal INST2 from the control unit 223, and the read position information table TBL-M2- 3, a position information message PSM-2 (see FIG. 11) for transmitting the position information <P _M2 , V _M2 , α _M2 , T ₂ > is generated. Then, the information generation means 224 of the wireless device M2 broadcasts the generated location information message PSM-2.

Then, the wireless devices M1 and M3 receive the location information message PSM-2 broadcast from the wireless device M2. And the control means 223 of the radio | wireless apparatus M1 uses the positional information table TBL-M1-2 for the positional information <P _M2 , V _M2 , α _M2 , T ₂ > of the vehicle C2 included in the received positional information message PSM-2. (See (a) of FIG. 9) and the position information table TBL-M1-2 is updated to the position information table TBL-M1-3 (see (a) of FIG. 10). Similarly, the control unit 223 of the wireless device M3 updates the position information table TBL-M3-2 (see (c) of FIG. 9) to the position information table TBL-M3-3 ((c of FIG. 10). )reference).

The control unit 223 of the wireless device M2 does not output the instruction signal INST2 to the information generation unit 224 when the error ΔPS is equal to or less than the threshold value (= 0.1 V _T2 ) × T. Accordingly, when the error ΔPS is equal to or less than the threshold value (= 0.1 V _T2 ) × T, the wireless device M2 transmits the position information <P _M2 , V _M2 , α _M2 , T ₂ > acquired at the timing T2. do not do.

  And the control means 223 of the radio | wireless apparatus M2 maintains position information table TBL-M2-2 (refer (b) of FIG. 9).

Further, since the control unit 223 of the wireless devices M1 and M3 does not receive the position information message PSM from the wireless device M2 at the timing T2, the position information received from the wireless device M2 at the timing T1 <P _M2 , V _M2 , α _M2 , Based on T ₁ >, the position of the vehicle C2 at the timing T2 is predicted using the equations (1) and (2), and the predicted position P _{M2_P} = (x _{T2_P} , y _{T2_P} ) is acquired.

Then, the control unit 223 of the wireless device M2 determines whether or not the error ΔPS is larger than the threshold value (= 0.1V × T) at the timing T3 when the period T further passes from the timing T2, and the error ΔPS is the threshold value. When larger than (= 0.1 V × T), the positional information <P _M2 , V _M2 , α _M2 , T ₃ > acquired at the timing T3 is transmitted. In addition, when the error ΔPS is equal to or less than the threshold value (= 0.1 V × T) at the timing T3, the wireless device M2 does not transmit the position information <P _M2 , V _M2 , α _M2 , T ₃ > and already holds it. Maintaining the position information table TBL-M2.

As described above, the wireless device M2 transmits the position information <P _M2 , V _M2 , α _M2 , T _n−k > at the timing Tn−k (n is an integer greater than or equal to 2 and k is a positive integer). Thereafter, the predicted position of the vehicle C2 at the timing Tn predicted based on the position information <P _M2 , VM ₂ , α _M2 , T _n−k > and the actual position of the vehicle C 2 at the timing Tn (position information <P _M2 , It is determined whether or not an error ΔPS with respect to V _M2 , α _M2 , T _n > is greater than a threshold value (= 0.1 V × T), and the error ΔPS is a threshold value (= 0.1 V × T). Is larger than the position information <P _M2 , VM ₂ , α _M2 , T _n > acquired at the timing Tn, and the position information table TBL-M2 held by the self is stored in the position information <P _M2 , V _M2 , α _M2, updated by _n>.

In addition, when the error ΔPS is equal to or less than the threshold value (= 0.1 V × T), the wireless device M2 already holds the position information <P _M2 , V _M2 , α _M2 , T _n > without transmitting it. The position information table TBL-M2 is maintained.

The wireless device M2 repeats the above-described operation every cycle T from the timing T1 (= t1) at which the position information <P _M2 , V _M2 , α _M2 , T ₁ > is transmitted.

And when it becomes the timing T5 (= t5) which passed only the period NT from timing T1 (= t1), the radio | wireless apparatus M2 will acquire the positional information <P _M2 , V _M2 , α _M2 , T ₅ > of the vehicle C2, The acquired position information <P _M2 , VM ₂ , α _M2 , T ₅ > is stored and transmitted in the position information message PSM (see (c) of FIG. 6), and the position information <P _M2 , V _M2 , α _M2, and updates the location information table TBL-M2 by _{T 5>.} That is, when only the period NT elapses from the timing at which the position information indicating the position of the vehicle C2 is transmitted, the wireless device M2 performs prediction of the position of the vehicle C2 and determination of whether or not the error ΔPS is greater than the threshold value. The acquired position information <P _M2 , VM ₂ , α _M2 , T _NT > is transmitted. That is, the wireless device M2 always transmits the actually measured position information <P _M2 , V _M2 , α _M2 , T _nNT > every period NT.

  When (N + 0.5) × T has elapsed from the timing T1 (= t1), the vehicles C1 to C3 have moved to the positions shown in FIG.

  When receiving the position information message PSM-1 (see FIG. 8) from the wireless device M2 at the timing T1, the control means 223 of the wireless devices M1 and M3 receives a timer having a built-in timer period (N + 0.5) × T (see FIG. 8). It is determined whether or not a new location information message PSM is received from the wireless device M2 within the set timer period (= (N + 0.5) × T).

  When the control unit 223 of the wireless devices M1 and M3 determines that the new location information message PSM has not been received from the wireless device M2 within the timer period (= (N + 0.5) × T), It detects that a packet loss has occurred in the transmitted packet, generates an instruction signal INST3, and outputs it to the information generation means 224.

  Then, the information generation unit 224 of the radio apparatuses M1 and M3 generates a transmission request message ARQ for requesting transmission of the location information message PSM in response to the instruction signal INST3 from the control unit 223, and transmits the transmission request message ARQ to the radio apparatus M2. To do. In this case, the information generation unit 224 of the wireless device M1 generates a transmission request message ARQ composed of ARQ1 = [IPaddM2 / IPaddM1 / position information transmission request], and the information generation unit 224 of the wireless device M3 generates ARQ2 = [IPaddM2 / IPaddM3 / position information transmission request] is generated. Then, the information generation means 224 of the wireless devices M1 and M3 respectively measure the interference amount in the wireless devices M1 and M3, and when the measured interference amount is the smallest, the transmission request messages ARQ1 and ARQ2 are respectively transmitted to the wireless devices. Send to M2.

  The control means 223 of the wireless device M2 receives the transmission request messages ARQ1 and ARQ2 transmitted from the wireless devices M1 and M3, respectively, generates an instruction signal INST2 according to the received transmission request messages ARQ1 and ARQ2, and generates information The data is output to the generation unit 224.

Further, when receiving the transmission request messages ARQ1 and ARQ2, the control unit 223 of the wireless apparatus M2 detects the reception power PWr when the transmission request messages ARQ1 and ARQ2 are received, and sets the transmission power PWt with the detected reception power PWr. dividing to calculates the channel gain G _C. The transmission power PWt is a transmission power used in the wireless network 100 and is known. Accordingly, the control means of the radio device M2 223 can be easily computed channel gain _{G C.}

The processing gain of the CDMA system is a communication system incorporated in a wireless network 100 and _{G P,} the amount of interference in a radio apparatus M2 and _{P I,} the noise and _{P N,} the control unit 223 of the radio device M2, the following The transmission power P is determined so as to satisfy the equation.

P / G _C > (P _I + P _N ) / _GP (3)

  Then, the control unit 223 of the radio apparatus M2 outputs the determined transmission power P to the information generation unit 224.

Then, the information generation means 224 of the wireless device M2 responds to the instruction signal INST2 from the control means 223, and the method described above for the position information message PSM including the position information <P _M2 , V _M2 , α _M2 , n × NT>. And the generated position information message PSM is broadcast with the transmission power P.

  As a result, the wireless devices M1 and M3 can accurately receive the location information message PSM from the wireless device M2.

FIG. 12 is a diagram for explaining in detail the method of transmitting the location information message. For example, the wireless device M2 transmits the position information <P _M2 , V _M2 , α _M2 , T1> at timing T1 (= t1) (see (a) in FIG. 12), and the position information <P _M2 , V _M2 , α _M2 , T2> is not transmitted (see (b) of FIG. 12), and position information <P _M2 , V _M2 , α _M2 , T3> is transmitted at timing T3 (= t3) (FIG. 12). (See (c)).

In this case, since the wireless devices M1 and M3 do not receive the position information <P _M2 , V _M2 , α _M2 , T2> from the wireless device M2 at the timing T2 (= t2), the wireless device M2 at the timing T1 (= t1). Based on the position information <P _M2 , VM ₂ , α _M2 , T1> received from the vehicle, the position at the timing T2 (= t2) of the vehicle C2 on which the wireless device M2 is mounted is predicted by the method described above, and the prediction is made Using the position, the distances between the vehicles C1, C3 and the vehicle C2 are calculated, respectively.

The wireless device M2 determines the position of the vehicle C2 at the timing T2 (= t2) based on the position information <P _M2 , _VM2 , _αM2 , T1> acquired at the timing T1 (= t1) by the method described above. Predict and calculate the distance between the vehicle C2 and the vehicles C1, C3 using the predicted position.

Note that the wireless device M2 also acquires the actual position of the vehicle C2 using the GPS receiver 3 and the INS device 4 at the timing T2 (= t2). The reason why the distance between the vehicles C1 and C3 is not calculated is that the wireless devices M1 and M3 mounted on the vehicles C1 and C3 respectively receive the actual position of the vehicle C2 at the timing T2 (= t2) from the wireless device M2. Vehicles C1, C3 using the predicted position of the vehicle C2 at the timing T2 (= t2) predicted based on the position information <P _M2 , V _M2 , α _M2 , T1> at the timing T1 (= t1). Between the vehicle C2 and the vehicles C1 and C3 using the actual position of the vehicle C2 at the timing T2 (= t2). When the distance is calculated, the distance between the vehicles C1, C3 and the vehicle C2 calculated in the wireless devices M1 and M3 deviates from the distance between the vehicle C2 and the vehicles C1 and C3 calculated in the wireless device M2. is there.

As described above, when the wireless device M2 does not transmit the position information <P _M2 , V _M2 , α _M2 , T2> at the timing T2 (= t2), the wireless devices M1 to M3 are positioned at the timing T1 (= t1). The distance between the vehicle C2 and the vehicles C1 and C3 is calculated using the predicted position of the vehicle C2 predicted using the information <P _M2 , V _M2 , α _M2 , T1>. That is, the wireless devices M1 to M3 calculate the distance between the vehicle C2 and the vehicles C1 and C3 using the same position information.

Since the wireless device M2 transmits the position information <P _M2 , V _M2 , α _M2 , T3> at the timing T3 (= t3) after the timing T2 (= t2), the wireless devices M1 to M3 have the positional information < The distance between the vehicle C2 and the vehicles C1 and C3 is calculated using P _M2 , V _M2 , α _M2 , T3>.

As another transmission pattern of the position information, the wireless device M2 transmits the position information <P _M2 , V _M2 , α _M2 , T1> at the timing T1 (= t1) (see (a) in FIG. 12), and the timing T2 Position information <P _M2 , V _M2 , α _M2 , T2> is not transmitted (see (b) of FIG. 12), and position information <P _M2 , V _M2 , α _M2 , T3> is also received at timing T3 (= t3) Is not transmitted (see (d) of FIG. 12).

In this case, the wireless devices M1 and M3 wirelessly transmit positional information < _PM2 , _VM2 , _αM2 , T2>, < _PM2 , _VM2 , _αM2 , T3> indicating the position of the vehicle C2 at the timings T2 and T3. Since the position is not received from the device M2, the position of the vehicle C2 at the timings T2 and T3 is predicted using the position information <P _M2 , V _M2 , α _M2 , T1> received from the wireless device M2 at the timing T1, and the predicted position Is used to calculate the distance between the vehicles C1, C3 and the vehicle C2.

The wireless device M2 also predicts the position of the vehicle C2 at the timings T2 and T3 using the position information <P _M2 , V _M2 , α _M2 , T1> acquired at the timing T1, and uses the predicted position to The distance between C2 and vehicles C1, C3 is calculated.

  Thus, when the radio | wireless apparatus M2 does not transmit position information twice continuously, the radio | wireless apparatuses M1-M3 are vehicles C2 for every period T based on the position information which the radio | wireless apparatus M2 transmitted at the start of the period NT. Is calculated, and the distance between the vehicle C2 and the vehicles C1 and C3 is calculated using the predicted position.

Note that even when the wireless device M2 does not transmit the position information three times after the timing T1 (= t1), the wireless devices M1 to M3 still have position information <the position information indicating the actual position of the vehicle C2 at the timing T1 < Using P _M2 , V _M2 , α _M2 , T1>, the position of the vehicle C2 is predicted for each period T, and the distance between the vehicle C2 and the vehicles C1, C3 is calculated using the predicted position.

As described above, the radio apparatus M2 determines whether or not the error ΔPS is larger than the threshold value (= 0.1 V × T) every transmission cycle T, and the error ΔPS is larger than the threshold value (= 0.1 V × T). Is larger than the transmission period T, the position information <P _M2 , V _M2 , α _M2 , n × T> is transmitted every transmission cycle T, and the error ΔPS is less than or equal to the threshold value (= 0.1 V × T). The position information <P _M2 , V _M2 , α _M2 , n × T> is transmitted at a long interval. Then, when the error ΔPS is larger than the threshold value (= 0.1 V × T), the wireless devices M1 and M3 send the position information <P _M2 , V _M2 , α _M2 , n × T> for each transmission cycle T. When the error ΔPS is received from M2 and the error ΔPS is equal to or less than the threshold value (= 0.1 V × T), the position information <P _M2 , V _M2 , α _M2 , n × T> is transmitted at an interval longer than the transmission cycle T. Receive from.

As a result, the position information <P _M2 , V _M2 , α _M2 , n × T> is transmitted / received at a transmission interval T or more of the Hello message.

Therefore, according to the present invention, the position information <P _M2 , V _M2 , α _M2 , n × T> can be exchanged efficiently.

Also, the wireless devices M1 and M3 adjacent to the wireless device M2 that is the transmission source of the positional information <P _M2 , V _M2 , α _M2 , n × T> are transmitted from the wireless device M2 to the positional information <P _M2 , V _M2 , α. _{When M2} , nxT> is not received, the positional information < _PM2 , _VM2 , _αM2 , (nk) × received from the wireless device M2 at timing Tn-k (= (nk) * T) Based on T>, the position of the vehicle C2 at the timing Tn (= n × T) is predicted, and the predicted position P _{M2_P} , is determined based on the actually measured position P _M2 and the threshold (= 0.1 V × T). Only an error ΔPS less than.

Therefore, according to the present invention, even when the source wireless device M2 does not transmit the position information <P _M2 , V _M2 , α _M2 , n × T>, the wireless devices M1 and M3 adjacent to the wireless device M2 accurate position information _{<P M2_P, V M2, α} M2, n × T> can be acquired.

Further, the wireless devices M1 and M3 determine whether or not the position information message PSM is received from the wireless device M2 within the timer period of (N + 0.5) × T, and the position information from the wireless device M2 within the timer period. When the message PSM is not received, the transmission request message ARQ is transmitted to the wireless device M2, and the position information <P _M2 , _VM2 , α _M2 , n × NT> is received from the wireless device M2. Location information can be acquired for each NT.

  FIG. 13 is a diagram showing still another example of the location information message PSM. 14 and 15 are diagrams showing still another example of the position information table TBL.

  Based on the position information table TBL-M3-3 (see (c) of FIG. 10), the control unit 223 of the wireless device M3 has an error between the predicted position and the actual position of the vehicle C3 on which the wireless device M3 is mounted. When the threshold value is exceeded, an instruction signal for updating the first row of the position information table TBL-M3-5 shown in FIG. 14 using the actual position information of the vehicle C3 acquired at the timing T2 and generating the position information message PSM INST2 is generated and output to the information generation means 224.

Then, the information generation unit 224 of the wireless device M3 stores the terminal number M3 of the wireless device M3 and the transmission destination DST = BROADCAST in the header HED in response to the instruction signal INST2 from the control unit 223, and is stored in the storage unit 221. Message of location information <P _M3 , V _M3 , α _M3 , T ₂ >, terminal number M3 and transmission interval N × T (= 4T) in the location information table TBL-M3-3 (see (c) of FIG. 10). It is stored in the MS 1 and is adjacent to the position information <P _M2 , V _M2 , α _M2 , T ₂ > and the terminal number M2 of the position information table TBL-M3-3 (see (c) of FIG. 10) and the radio apparatus M3. A position information message PSM-3 (see FIG. 13) in which the number of wireless devices # neighbor = 1 is stored in the message MS2 is generated.

  Then, the information generation unit 224 of the wireless device M3 broadcasts the location information message PSM-3 via the wireless interface module 21 and the antenna 1.

  Thereafter, the control unit 223 of the wireless device M3 changes the transmitted field of the position information table TBL-M3-3 from “NO” to “YES”, and changes the position information table TBL-M3-3 to the position information table TBL-M3. Update to -5 (see FIG. 14).

  Before receiving the position information message PSM-3 from the wireless apparatus M3, the wireless apparatus M4 mounted on the vehicle C4 that is a succeeding vehicle of the vehicle C3 receives the position information table TBL-M4-1 (see FIG. 15A). Is stored in the storage means 221.

Then, when receiving the location information message PSM-3 from the radio device M3, the control means 223 of the radio device M4 detects SRC = M3 stored in the header HED of the received location information message PSM-3 and detects the location information. It is detected that the message PSM-3 is transmitted from the wireless device M3. The control means 223 of the wireless device M4 also transmits the terminal number M3, the position information <P _M3 , V _M3 , α _M3 , T ₂ > and the transmission interval NT (= 4T) stored in the message MS1 of the position information message PSM-3. ) Is detected. Further, the control means 223 of the wireless device M4 detects the terminal number M2 and the position information <P _M2 , V _M2 , α _M2 , T ₂ > stored in the message MS2 of the position information message PSM-3.

Then, the control unit 223 of the wireless device M4 reads the position information table TBL-M4-1 (see (a) of FIG. 15) stored in the storage unit 221 and stores the read position information table TBL-M4-1. storing the _{ID M3} in the column of the terminal number, and stores the position information _{<P M3, V M3, α} M3, T 2> to the column of the terminal position information, and stores the _{ID M3} in the column of the transmission terminal number, sent “NO” is stored in the column of “No.”, and since the terminal number ID _M3 and the transmission terminal number ID _M3 match, “YES” is stored in the column of the peripheral terminal.

Further, the control means 223 of the wireless device M4 stores ID _M2 in the terminal number column, stores position information <P _M2 , V _M2 , α _M2 , T ₂ > in the terminal position information column, and transmits the transmission terminal number. ID _M3 is stored in the field “No.”, “NO” is stored in the transmitted field, and “NO” is stored in the field of the peripheral terminal because the terminal number ID _M2 does not match the transmission terminal number ID _M3 . As a result, the position information table TBL-M4-1 is updated to the position information table TBL-M4-2 (see FIG. 15B).

The control means 223 of the wireless device M4 stores “NO” in the column of the peripheral terminal corresponding to the terminal number ID _M2 in the position information table TBL-M4-2, so the terminal position information corresponding to the terminal number ID _M2 <P _M2 , V _M2 , α _M2 , T ₂ > detects that it is the transferred position information.

The control unit 223 of the wireless device M4 updates the position information table TBL-M4-1 to the position information table TBL-M4-2, and then transmits the position information <P _M3 , V _M3 , α _M3 , T from the wireless device M3. Upon receiving the _3>, the position information _{<P M3, V M3,} position _{information T 3} is stored in the position information table TBL-M4-2 of _{α M3, T 3><P} M3, V M3, α M3, T is greater than _{T 2} of the _2>, the position information _{<P M3, V M3, α} M3, T 2> position information _{<P M3, V M3,} updates the alpha _{M3, T 3>.}

In addition, when the wireless device M2 receives the same position information from the wireless devices M1 and M3 mounted on the vehicles C1 and C3 traveling before and after the vehicle C2 on which the wireless device M2 is mounted, the wireless device M2 further transfers the received position information. Never do. For example, when the wireless device M1 broadcasts the positional information <P _M1 , V _M1 , α _M1 , T ₁ > of the vehicle C1, the wireless devices M2 and M3 receive the positional information <P _M1 , V _M1 , α _M1 , T _1. > Is received. Then, the wireless device M3 receives the position information <P _M3 , V _M3 , α _M3 , T ₁ > of the vehicle C3 and the position information <P _M1 , V _M1 , α _M1 , T ₁ > received from the wireless device M1. The wireless device M2 receives the location information <P _M3 , V _M3 , α _M3 , T ₁ > and the location information <P _M1 , V _M1 , α _M1 , T ₁ > from the radio device M3.

Then, since the wireless device M2 has received the position information <P _M1 , V _M1 , α _M1 , T ₁ > from the wireless device M1 and the wireless device M3, the position information <P _M1 , V _M1 , α _M1 , T ₁ > Is not forwarded further.

Even if the position information <P _M1 , V _M1 , α _M1 , T ₁ > is further transferred, the vehicle traveling around the vehicle C2 (the vehicle traveling in front of the vehicle C1 and the vehicle traveling behind the vehicle C3) The vehicle C4 and the like that have received the position information <P _M1 , V _M1 , α _M1 , T ₁ > is unnecessary position information.

  Therefore, when each wireless device receives the same position information from a wireless device mounted on a vehicle traveling before and after the vehicle on which it is mounted, the wireless device does not transfer the received position information, The overhead when exchanging information is reduced. In other words, when each wireless device receives the same position information from a wireless device mounted on a vehicle traveling in front of and behind the vehicle on which it is mounted, when the position information is exchanged while avoiding duplicate transmission The overhead is reduced.

In the above, it has been described that the wireless device M2 transmits the position information <P _M2 , V _M2 , α _M2 , n × NT> in the transmission cycle NT. However, in the present invention, the wireless device M2 is not limited thereto. The position information <P _M2 , V _M2 , α _M2 , n × NT> may be transmitted in the transmission cycle NT adjusted according to the speed V _M2 .

More specifically, the control unit 223 of the radio device M2, the reference speed _{V M2} speed (= e.g., 10 km / h) below the, set N to twice (N = 8), the speed _{V M2} is When the reference speed is equal to or higher than 10 km / h, N is set to the original value (N = 4), the transmission cycle NT is adjusted, and the adjusted transmission cycle NT is output to the information generation unit 224. . Then, the information generation unit 224 of the wireless device M2 receives the adjusted transmission cycle NT from the control unit 223, and transmits the position information message PSM generated by the above-described method with the adjusted transmission cycle NT.

  Since there are relatively many vehicles in a congested corps train or at an intersection, if each of the wireless devices M1 to M30 transmits position information in the transmission cycle NT in such a situation, the communication amount of the position information exceeds the channel capacity. there is a possibility.

  Therefore, as described above, the transmission cycle NT is adjusted according to the speed V of each vehicle, and the position information is transmitted in the adjusted transmission cycle NT.

  In the above, the wireless device M2 transmits the position information of the vehicle C2 at the transmission cycle T or more, the wireless devices M1 and M3 receive the position information from the wireless device M2, and the wireless device M3 receives the position information from the wireless device M2. However, each of the wireless devices M1 to M30 constituting the wireless network 100 exchanges the position information by transmitting / receiving and transferring the position information at the transmission cycle T or more by the method described above. Further, when each of the wireless devices M1 to M30 constituting the wireless network 100 cannot receive the position information message PSM transmitted from the adjacent wireless device due to the packet loss, the wireless device M1 to M30 transmits the transmission request message ARQ and transmits the position information message PSM. Is received again. Further, each of the wireless devices M1 to M30 configuring the wireless network 100 adjusts the transmission cycle NT according to the speed of the vehicle on which the wireless device 100 is mounted, and transmits the position information at the adjusted transmission cycle NT.

  Therefore, according to this invention, each radio | wireless apparatus M1-M30 can exchange position information efficiently and correctly.

  Each of the wireless devices M1 to M30 efficiently exchanges position information with the adjacent wireless devices by the above-described method, and acquires the position information of the vehicles existing around the vehicle on which the wireless devices M1 to M30 are mounted.

Then, the control unit 223 of the wireless device M1~M30, based on the obtained position information, and the vehicle itself is mounted _{C Self,} vehicle _{C Front} that travels immediately before or after the vehicle _{C Self, Back} Is calculated, and it is determined whether or not the calculated distance L is less than the safety distance. When the distance L is less than the safety distance, the instruction signal INST4 is generated and output to the information generation means 224.

The information generating means 224 of each of the wireless devices M1 to M30 generates a danger forecast message in response to the instruction signal INST4 received from the control means 223, and the generated danger forecast message is wirelessly mounted on the vehicles C _{Front and Back.} Transmit to the device M _{Front, Back} .

When the control unit 223 of the wireless device M _{Front, Back} receives the danger forecast message from each of the wireless devices M1 to M30, it generates a brake signal and outputs it to the speed reducer. The speed reducer decelerates according to the brake signal.

  FIG. 16 is a flowchart for explaining an operation of transmitting and receiving position information between adjacent wireless devices. In FIG. 16, an operation of transmitting / receiving position information between adjacent wireless devices when the wireless device M <b> 2 is a location information transmission source and the wireless device M <b> 1 is a location information transmission destination will be described. Further, the flowchart shown in FIG. 16 is a flowchart for explaining a position information transmission / reception operation in a time period equal to the transmission cycle NT (for example, a time period from timing t1 to timing t5).

When a series of operations is started, the wireless device M2 sets n = 1 (step S1). Then, the wireless device M2 acquires the position information P _Self n (= <P _M2 , V _M2 , α _M2 , Tn>) of the vehicle C2 on which the wireless device M2 is mounted by the GPS receiver 3 and the INS device 4 at the timing Tn. The acquired position information P _Self n is registered in the position information table TBL-M2, and a position information message PSM-n including the position information P _Self n is generated and transmitted (step S2).

  The wireless device M1 receives the location information message PSM-n from the wireless device M2, and updates the location information table TBL-M1 with the received location information message PSM-n (step S3).

  Thereafter, the wireless device M1 sets a timer period (= (N + 0.5) T) (step S4).

Then, the wireless device M2 determines whether or not the timing has reached Tn + k (step S5). When the timing has reached Tn + k, the position information P _{Self of} the vehicle C2 on which the radio device M2 is mounted by the GPS receiver 3 and the INS device 4 is determined. n + k (= <P _M2 , V _M2 , α _M2 , Tn + k>) is acquired at timing Tn + k (step S6).

Thereafter, the wireless device M2 predicts the position of the vehicle C2 at the timing Tn + k based on the position information P _Self n by the above-described method, and the predicted position P _{M2_P} and the position P _M2 included in the position information P _Self n + k. Is calculated (step S7).

  Then, the wireless device M2 determines whether or not the error ΔPS is larger than a threshold value (= 0.1 VT) (step S8).

When it is determined in step S8 that the error ΔPS is larger than the threshold value (= 0.1 VT), the wireless device M2 updates the position information table TBL-M2 with the position information P _Self n + k acquired at the timing Tn + k. The position information message PSM-n + k including the position information P _Self n + k is generated by the above-described method, and the generated position information message PSM-n + k is transmitted (step S9).

  The wireless device M1 receives the location information message PSM-n + k transmitted from the wireless device M2, and updates the location information table TBL-M1 with the received location information message PSM-n + k (step S10).

On the other hand, when it is determined in step S8 that the error ΔPS is equal to or less than the threshold value (= 0.1 VT), the wireless device M2 stops transmitting the position information P _Self n + k (step S11).

  After step S10 or step S11, the wireless apparatus M2 determines whether or not NT has elapsed from the timing T1 (step S12), and sets n = n + 1 when NT has not elapsed from the timing T1 (step S12). S13). Thereafter, the series of operations proceeds to step S5. Then, in step S12, the above-described steps S5 to S13 are repeatedly executed until it is determined that NT has elapsed from the timing T1.

If it is determined in step S12 that only NT has elapsed from the timing T1, the wireless device M2 uses the GPS receiver 3 and the INS device 4 to indicate position information indicating the position of the vehicle C2 on which the wireless device M2 is mounted at the timing T1 + NT. P _Self 1 + NT is acquired, and a position information message PSM-1 + NT including the acquired position information P _Self 1 + NT is generated and transmitted (step S14).

  Thereafter, the wireless device M1 determines whether or not position information has been received within the timer period (= (N + 0.5) T) (step S15), and is positioned within the timer period (= (N + 0.5) T). When it is determined that the information is not received, a position information transmission request message ARQ is generated, and the generated transmission request message ARQ is transmitted to the radio apparatus M2 (step S16).

  Then, the wireless device M2 receives the transmission request message ARQ from the wireless device M2, and retransmits the location information message PSM-1 + NT according to the received transmission request message ARQ (step S17).

  In step S15, when it is determined that the position information is received within the timer period (= (N + 0.5) T), or after step S17, the wireless device M1 uses the position information message PSM-1 + NT to transmit the position information table TBL. -M1 is updated (step S18). As a result, a series of operations is completed.

The wireless device M2 repeatedly executes the above-described steps S1, S2, S5, S6 to S9, S11 to S14, and S17, and the position information of the vehicle C2 on which the wireless device M2 is mounted <P _M2 , V _M2 , α _M2 , Tn. > Is transmitted at the transmission cycle T or more, and the position information table TBL-M2 is created and updated, and the wireless device M1 repeatedly executes the above-described steps S3, S4, S10, S15, S16, and S18, and The position information <P _M2 , VM ₂ , α _M2 , Tn> is received from the wireless device M2 at a period T or more, and the position information table TBL− is received according to the received position information <P _M2 , VM ₂ , α _M2 , Tn>. Update M1.

The radio apparatuses M1 and M2 transmit and receive the position information <P _M2 , V _M2 , α _M2 , Tn> at a transmission period T or more of the Hello message by executing the flowchart shown in FIG. Therefore, the position information can be exchanged more efficiently than when the position information is exchanged by including it in the Hello message.

In addition, by executing the flowchart shown in FIG. 16, the radio apparatus M2 determines whether or not the error ΔPS is larger than the threshold value (= 0.1V × T) determined by the vehicle speed V (step). When the error ΔPS is equal to or smaller than the threshold value (= 0.1 V × T), the wireless device M2 does not transmit the position information (see step S11). In this case, the radio apparatuses M1 and M2 predict the position of the vehicle C2 at the timing Tn + k based on the position information P _Self n at the timing Tn, and set the predicted position as the position of the vehicle C2 at the timing Tn + k. Therefore, the radio apparatuses M1 and M2 can acquire a position close to the actual position P _M2 as the predicted position P _{M2_P} without exchanging position information. As a result, the wireless device M1 adjacent to the wireless device M2 can acquire the position of the vehicle C2 with high accuracy.

  FIG. 17 is a flowchart for explaining another operation of transmitting / receiving position information between adjacent wireless devices. In FIG. 17 as well, an operation of transmitting / receiving position information between adjacent wireless devices when the wireless device M2 is a transmission source of positional information and the wireless device M1 is a transmission destination of positional information will be described.

When a series of operation is started, the wireless device M2 determines whether the velocity V _M2 of the vehicle C2 that is stored in the position information table TBL-M2 falls below the reference speed (step S21).

In step S21, when the speed _{V M2} is determined to be less than the reference speed, the wireless device M2 adjusts the transmission cycle to 2NT (step S22).

On the other hand, when it is determined in step S21 that the speed _VM2 is equal to or higher than the reference speed, the wireless device M2 adjusts the transmission cycle to NT (= original transmission cycle) (step S23).

  Then, after step S22 or step S23, the position information is transmitted from the wireless device M2 to the wireless device M1 according to the flowchart shown in FIG. 16 described above (step S24). Thereafter, the series of operations ends.

  In FIG. 17, when step S24 is executed after step S22, it is determined in step S12 of the flowchart shown in FIG. 16 whether or not 2NT has elapsed from the timing T1.

The wireless device M2 repeatedly executes the above-described steps S1, S2, S5, S6 to S9, S11 to S14, S17, S21 to S23, and the positional information of the vehicle C2 on which the wireless device M2 is mounted <P _M2 , V _M2 , α _M2 , Tn> is transmitted at a transmission cycle (2NT or NT) adjusted according to the speed of the vehicle C2, and the position information table TBL-M2 is created and updated. The wireless device M1 performs steps S3, S4 described above. S10, S15, S16, S18 repeatedly running, position information _{<P M2, V M2, α} M2, Tn> was received in the period 2NT or periodic NT from the wireless device M2, the received location information of the vehicle C2 < The position information table TBL-M1 is updated based on P _M2 , V _M2 , α _M2 , Tn>.

The wireless devices M1 and M2 execute the flowchart shown in FIG. 17, so that the positional information <P _M2 , V _M2 , and the transmission cycle NT or 2NT according to the speed of the vehicle C2 on which the wireless device M2 as the transmission source is mounted. α _M2 , Tn> is transmitted and received. Therefore, the position information <P _M2 , V _M2 , α _M2 , Tn> can be transmitted and received by automatically adjusting the transmission cycle. As a result, even if the vehicle is present in a traffic jam platoon or at a point where there are relatively many vehicles, such as an intersection, the traffic information is set to be equal to or less than the channel capacity, and the position information <P _M2 , V _M2 , α _M2 , Tn> Can be sent and received. Further, automatically adjusting the transmission cycle automatically adjusts the overhead of the position information, so that the overhead information can be controlled to transmit / receive the position information <P _M2 , V _M2 , α _M2 , Tn>. .

  When the flowchart shown in FIG. 17 is executed, wireless device M1 receives the position information transmission interval (= 2NT or NT) together with the position information of vehicle C2 from wireless device M2. Accordingly, the wireless device M1 sets a timer period (= ARQ timer) longer than the transmission interval (= 2NT or NT) based on the received transmission interval (= 2NT or NT).

Wireless devices M1, M2 other wireless devices M3~M30 also according to the flowchart shown in any of FIGS. 16 and 17 described above, the vehicle _{C neighbor} adjacent to the position information of the vehicle _{C Self} itself are mounted and a vehicle _{C Self} Get location information.

  FIG. 18 is a perspective view showing an automobile according to the present invention. In the present invention, each of vehicles C1 to C30 includes automobile 200 shown in FIG. The automobile 200 includes a main body 210, a wireless device 220, and a speed reducer 230.

  The wireless device 220 and the speed reducer 230 are mounted on the main body 210. The wireless device 220 includes the wireless devices M1 to M30 described above, and acquires the position information of the automobile 200 and the position information of the automobile adjacent to the automobile 200 according to the flowchart shown in FIG. 16 and FIG. A position information table TBL is created.

  And the radio | wireless apparatus 220 calculates the distance L of the motor vehicle 200 and the motor vehicle adjacent to the motor vehicle 200 based on the created position information table TBL, and determines whether the calculated distance L is less than the safety distance. judge.

  When the wireless device 220 determines that the distance L is less than the safety distance, the wireless device 220 determines whether the vehicle adjacent to the vehicle 200 is a vehicle that is traveling immediately before the vehicle 200.

  Then, when the vehicle adjacent to the vehicle 200 is a vehicle that is traveling immediately before the vehicle 200, the wireless device 220 generates a brake signal and outputs the brake signal to the reduction device 230.

  On the other hand, when the car adjacent to the car 200 is a car that is running immediately after the car 200, the wireless device 220 generates and transmits a danger forecast message.

  In addition, when the radio apparatus 220 receives a danger forecast message from another radio apparatus, the radio apparatus 220 generates a brake signal and outputs the brake signal to the speed reducer 230.

  When receiving a brake signal from wireless device 220, reduction device 230 reduces the speed of automobile 200.

  FIG. 19 is a flowchart for explaining vehicle safety control using position information. In addition, the flowchart shown in FIG. 19 is a flowchart for demonstrating the safety control of the vehicle in the transmission source of a positional information.

According to the flowchart shown in any of FIGS. 16 and 17 described above, each wireless device M1~M30 acquires the position information of the vehicle _{C neighbor} adjacent to the position information and the vehicle _{C Self} vehicle _{C Self} itself are mounted Registered in the position information table TBL.

  And each radio | wireless apparatus M1-M30 determines whether the positional information was transmitted (step S31).

When it is determined in step S31 that the position information has been transmitted, each of the wireless devices M1 to M30, based on the position information table TBL held by itself, the vehicle C _Self and the vehicle C _Self mounted on the wireless device M1 to M30. The distance L between the vehicle C adjacent to and the vehicle C _neighbor is calculated (step S32).

On the other hand, when it is determined in step S31 that the position information has not been transmitted, each of the wireless devices M1 to M30 predicts the position of the vehicle C _{Self at} the timing Tn using the position information at the timing Tn-k (step S33). ) Based on the predicted position and the position information table TBL, the distance L between the vehicle C _Self on which the vehicle is mounted and the vehicle C _neighbor adjacent to the vehicle C _Self is calculated (step S34).

  And after step S32 or step S34, each radio | wireless apparatus M1-M30 determines whether the calculated distance L is less than a safe distance (step S35).

  When it is determined in step S35 that the distance L is not less than the safe distance, the series of operations returns to step S31, and the above-described steps S31 to S35 are repeatedly executed.

When it is determined in step S35 that the distance L is less than the safety distance, each of the wireless devices M1 to M30 further determines whether or not the vehicle C _neighbor is a front vehicle of the vehicle C _Self (step S36). .

When it is determined in step S36 that the vehicle C _neighbor is not the front vehicle of the vehicle C _Self (that is, when the vehicle C _neighbor is determined to be a vehicle following the vehicle C _Self ), the wireless devices M1 to M30 are: A danger forecast message is generated, and the generated danger forecast message is transmitted to the wireless device mounted on the vehicle C _neighbor (step S37).

On the other hand, when it is determined in step S36 that the vehicle C _neighbor is the front vehicle of the vehicle C _Self , each of the wireless devices M1 to M30 outputs a brake signal to the speed reduction device 230 of the vehicle C _Self in which the vehicle C self is mounted. (Step S38).

  And a series of operation | movement is complete | finished after step S37 or step S38.

  FIG. 20 is a flowchart for explaining another safety control of the vehicle using the position information. In addition, the flowchart shown in FIG. 20 is a flowchart for demonstrating the safety control of the vehicle in the transmission destination of a positional information.

  The flowchart shown in FIG. 20 is the same as the flowchart shown in FIG. 19 except that steps S31, S33, and S34 in the flowchart shown in FIG. 19 are replaced with steps S31A, S33A, and S34A, respectively.

  When a series of operations starts, each of the wireless devices M1 to M30 determines whether or not position information has been received (step S31A).

  When it is determined in step S31A that the position information has been received, step S32 described above is executed.

On the other hand, when it is determined in step S31A that the position information has not been received, each of the radio apparatuses M1 to M30 predicts the position of the vehicle C _{neighbor at} the timing Tn using the position information at the timing Tn-k (step S33A). ) Based on the predicted position and the position information table TBL, the distance L between the vehicle C _Self on which the vehicle is mounted and the vehicle C _neighbor adjacent to the vehicle C _Self is calculated (step S34A).

  And after step S32 or step S34A, a series of operation | movement transfers to step S35 mentioned above, and step S35-step S38 are performed. Thereby, a series of operation | movement is complete | finished.

In the above, the wireless device M2 when the velocity V _M2 of the vehicle C2 is less than the reference speed, adjusts the transmission period of location information 2NT, when the speed V _M2 of the vehicle C2 is the reference speed or higher, the position Although it has been described that the transmission cycle of information is adjusted to the original transmission cycle NT, in the present invention, the speed V of the vehicles C1 to C30 on which the wireless devices M1 to M30 are mounted is not limited to this. If the vehicle speed is lower than, the position information transmission cycle is adjusted to a relatively long transmission cycle. If the speed V of the vehicles C1 to C30 on which the vehicle is mounted is equal to or higher than the reference speed, the position information transmission cycle is relatively short. What is necessary is just to adjust to a transmission period.

  In the above description, the wireless devices M1 to M30 are described as being mounted on a vehicle. However, in the present invention, the wireless devices M1 to M30 may be mounted on a motorcycle. Generally, it only has to be mounted on a moving body.

  In the present invention, the transmission interval included in the position information message PSM constitutes an “adjustment parameter” for adjusting the transmission cycle.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a wireless network in which each wireless device can efficiently exchange position information with a peripheral terminal. In addition, the present invention is applied to a wireless network that can control overhead and exchange position information with high accuracy. Furthermore, the present invention is applied to a wireless device used in a wireless network in which each wireless device can efficiently exchange position information with a peripheral terminal. Furthermore, the present invention is applied to a wireless device used in a wireless network that can control overhead and exchange highly accurate position information. Furthermore, the present invention is applied to a moving body including a wireless device used in a wireless network in which each wireless device can efficiently exchange position information with a peripheral terminal. Furthermore, the present invention is applied to a mobile body including a wireless device used in a wireless network that can control overhead and exchange highly accurate position information.

1 is a schematic diagram of a wireless network according to an embodiment of the present invention. It is a schematic block diagram which shows the structure of the radio | wireless apparatus shown in FIG. It is a functional block diagram of the IP module shown in FIG. It is a block diagram of the positional information table which the memory | storage means shown in FIG. 3 stores. It is a figure which shows the format of a positional info message. It is a figure for demonstrating the transmission method of a positional info message. It is a figure which shows the example of a position information table. It is a figure which shows the example of a positional info message. It is a figure which shows the other example of a position information table. It is a figure which shows the further another example of a position information table. It is a figure which shows the other example of a positional info message. It is a figure for demonstrating in detail the transmission method of a positional info message. It is a figure which shows the further another example of a positional info message. It is a figure which shows the further another example of a position information table. It is a figure which shows the further another example of a position information table. It is a flowchart for demonstrating the operation | movement which transmits / receives positional information between adjacent radio | wireless apparatuses. It is a flowchart for demonstrating the other operation | movement which transmits / receives positional information between adjacent radio | wireless apparatuses. It is a perspective view which shows the motor vehicle by this invention. It is a flowchart for demonstrating the safety control of the vehicle using a positional information. It is a flowchart for demonstrating the other safety control of the vehicle using a positional information.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Antenna, 2 Communication control part, 3 GPS receiver, 4 INS apparatus, 21 Wireless interface module, 22 IP module, 23 GPS module, 24 INS module, 100 Wireless network, 221 Storage means, 222 Calculation means, 223 Control means, 224 Information generating means, 200 automobile, 210 main body, 220, M1-M30 wireless device, 230 speed reducer, C1-C30 vehicle.

Claims (12)

A wireless network for performing wireless communication between mobile objects,
A first transmission period of a message that is mounted on the first mobile body and is periodically transmitted in the wireless network when an error between the actual position and the predicted position of the first mobile body is equal to or less than a threshold value. A first wireless device that transmits position information of the first moving body in a second transmission cycle longer than the transmission cycle of
A second wireless device mounted on a second mobile body adjacent to the first mobile body and receiving position information transmitted from the first wireless device ;
The first wireless device has the error at the second transmission timing after the second transmission cycle has elapsed since the transmission of the position information of the first moving body acquired at the first transmission timing. A wireless network that transmits position information indicating an actual position of the first moving body without determining whether or not it is equal to or less than a threshold value . It said first wireless device, based on the first position information acquired in the first mobile at the transmission timing, predicts the position of the first movable body for each of the first transmission period, When an error between the predicted position predicted and the actual position of the first moving body acquired at each first transmission cycle is equal to or less than the threshold, the actual position of the first moving body is indicated. transmission of each of the first transmission period of location information is stopped, before Symbol actual of the first moving body without determining the error of or less than the threshold value in the second transmission timing The wireless network according to claim 1, wherein location information indicating a location is transmitted.   The second wireless device performs the first transmission at each first transmission period based on the position information of the first moving body transmitted from the first wireless device at the first transmission timing. The wireless network according to claim 2, wherein the position of the moving body is predicted.   The radio according to claim 2, wherein when the error is larger than the threshold, the first radio device transmits position information indicating an actual position of the first moving body in the first transmission cycle. network.   The wireless network according to any one of claims 2 to 4, wherein the threshold is determined by a speed of the first moving body. When the second wireless device receives position information from the first wireless device, the second wireless device sets a timer period longer than the second transmission cycle, and within the set timer period, from the first wireless device. When the location information is not received, the location information transmission request is transmitted to the first wireless device,
The wireless network according to claim 1, wherein the first wireless device transmits the position information to the second wireless device at a timing with relatively little interference in response to the transmission request.   When the speed of the first moving body is slower than a reference speed, the first wireless device transmits the position information of the first moving body by setting the second transmission cycle to be relatively long. When the speed of the first moving body is equal to or higher than the reference speed, the position of the first moving body is set by relatively shortening the second transmission cycle in a range longer than the first transmission cycle. The wireless network of claim 1, wherein the information is transmitted. The first wireless device transmits an adjustment parameter for adjusting the length of the second transmission cycle together with the position information,
The wireless network according to claim 7, wherein the second wireless device receives the adjustment parameter, and adjusts a timer period for requesting transmission of the position information using the received adjustment parameter.   The said 2nd radio | wireless apparatus avoids duplication transmission and transmits the positional information on the said 1st mobile body received from the said 1st radio | wireless apparatus with the positional information on the said 2nd mobile body. The described wireless network.   The second wireless device is configured to detect the first moving body and the first moving body based on the position information of the second moving body and the position information of the first moving body received from the first wireless device. The wireless network according to claim 1, wherein a distance to the second moving body is calculated, and when the calculated distance is less than a safety distance, a danger forecast message is generated and transmitted to the first wireless device.   A radio apparatus comprising any one of the first and second radio apparatuses according to any one of claims 1 to 10. When the first radio apparatus according to claim 1 receives the position information of the first moving body transmitted in the second transmission cycle when the error is equal to or less than the threshold , the moving body acquiring position information of the distance the first on the basis of the positional information of the movable body and the position information of the mobile calculates the distance between the first mobile body and the mobile body, which is the calculated A second wireless device that outputs a brake signal when the safety distance is below a safe distance;
A moving body comprising: a speed reduction device that executes a speed reduction process when receiving the brake signal from the second wireless device.

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