JP2013025526A - Communication tag for driving support and driving support system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication tag for driving support and a driving support system capable of suppressing consumption of a battery.SOLUTION: A communication tag 10 comprises a short-range radio communication unit 11, a GPS module 15, a middle-range radio communication unit 13, and a control unit 50. The control unit 50 includes a communication tag detection unit 53, and a transmission cycle adjustment unit 55. The short-range radio communication unit 11 transmits and receives short-range radio communication. The GPS module 15 acquires position information on the communication tag 10 (itself). The middle-range radio communication unit 13 transmits the position information on itself that is acquired by the GPS module 15 by middle-range radio communication. The communication tag detection unit 53 detects another communication tag having the same function as the tag itself through the short-range radio communication unit 11. The transmission cycle adjustment unit 55 adjusts a transmission cycle of middle-range radio communication on the basis of a detection result of another communication tag.

Description

  The present invention relates to a communication tag for driving support and a driving support system that can suppress battery consumption.

  As this type of conventional technology, for example, there is a technology described in Patent Document 1. In this technique, a pedestrian carries an approach warning device and a data carrier is attached to the vehicle. The approach warning device and the data carrier can communicate with each other by RFID (Radio Frequency IDentification). While the pedestrian is traveling on the road, the approach warning device carried by the pedestrian transmits an interrogation radio wave to a predetermined zone (range). When the vehicle enters this zone, the data carrier receives the interrogation radio wave and returns a response radio wave to the interrogation radio wave. The approach warning device receives this response radio wave, detects the approach of the vehicle, and notifies the pedestrian.

JP 2003-173499 A

  By the way, in the technique of said patent document 1, it is necessary for the approach warning apparatus which a pedestrian carries around to transmit a question radio wave repeatedly in preparation for approach of a vehicle. Considering the approach speed of the vehicle to the pedestrian and the like, the size of the zone where the interrogation radio wave reaches needs to be set to about several tens to several hundred meters, for example. For this reason, the approach warning device needs to transmit the interrogation radio wave at a high output so as to reach the above distance. In addition, the approach warning device needs to always drive (or frequently) the function of monitoring the response radio wave in order to detect the response radio wave returned from the vehicle. For this reason, there was a problem that the battery of the approach warning device was consumed.

  The present invention focuses on the above points, and an object of the present invention is to provide a driving support communication tag and a driving support system that can suppress battery consumption.

  In order to solve the above-described problem, the present invention includes a second wireless communication unit, a communication tag detection unit, and a transmission cycle adjustment unit. The second wireless communication means transmits the position information of the communication tag by the second wireless communication method having a communication distance longer than that of the first wireless communication method. The communication tag detecting means detects another communication tag having the same function as the communication tag. The transmission cycle adjusting means adjusts the transmission cycle of the second wireless communication system based on the detection result of the other communication tag.

  According to the present invention, when another communication tag having the same function as the communication tag (that is, the same type tag) is detected, the second wireless communication having a longer communication distance than the first wireless communication method. The transmission process can be shared with the same type tag. Thereby, since the transmission cycle of the second wireless communication method can be lengthened, the consumption of the communication tag battery can be suppressed.

It is a schematic diagram showing an example of composition of driving support system 100 concerning a 1st embodiment. 2 is a diagram illustrating a configuration example of a communication tag 10. FIG. 3 is a diagram illustrating a configuration example of a control unit 50. FIG. It is a flowchart which shows the process of the communication tag 10 which concerns on 1st Embodiment. It is a flowchart which shows the processing content of step (S) 15 of the communication tag 10 which concerns on 1st Embodiment. It is a flowchart which shows the processing content of step (S) 17 of the communication tag 10 which concerns on 1st Embodiment. It is a figure which shows an example of transmission period Ts, Ts 'and reception period Tr, Tr' of middle-range wireless communication. FIG. 3 is a diagram illustrating an example of a monitor screen 7 mounted on a vehicle 3. 2 is a diagram illustrating an example of an HMI terminal 30. FIG. It is a figure which shows an example of transmission cycle Ts' and reception cycle Tr (communication cycle at the time of standby) of middle-range wireless communication. It is the driving assistance system 100, Comprising: It is a schematic diagram which shows the case where there are four pedestrians in a short-range wireless communication area. It is a flowchart which shows the processing content of step (S) 15 of the communication tag 10 which concerns on 2nd Embodiment. It is a flowchart which shows the process of the communication tag 10 which concerns on 3rd Embodiment. It is a flowchart (the 1) which shows the processing content of step (S) 15 of the communication tag 10 which concerns on 4th Embodiment. It is a flowchart (the 2) which shows the processing content of step (S) 15 of the communication tag 10 which concerns on 4th Embodiment. It is a figure (the 1) which shows typically the exchange method of the information in the short distance wireless communication which concerns on 5th Embodiment. It is FIG. (2) which shows typically the exchange method of the information in the short distance wireless communication which concerns on 5th Embodiment. It is FIG. (The 3) which shows typically the exchange method of the information in the short distance wireless communication which concerns on 5th Embodiment. It is a figure which shows an example of the recording format of exchange information.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to the drawings.
(Constitution)
FIG. 1 is a schematic diagram illustrating a configuration example of a driving support system 100 according to the first embodiment. This driving support system 100 is a system for notifying the driver of a vehicle of the presence of a pedestrian carrying a communication tag. The driving support system 100 includes, for example, a communication tag 10, an HMI (Human Machine Interface) terminal 30 paired with the communication tag 10 (that is, a connection setting), and the in-vehicle transceiver 5. The HMI terminal 30 is a mobile terminal such as a mobile phone having a display function, for example.

  In FIG. 1, the communication tag 10 (hereinafter referred to as communication tag 10a) carried by the pedestrian 1a and the HMI terminal 30 (hereinafter referred to as HMI terminal 30a) paired with the communication tag 10a are carried. Is illustrated. In this example, another pedestrian 1b exists around the pedestrian 1a. The pedestrian 1b carries a communication tag 10 (hereinafter referred to as 10b) carried by the pedestrian 1b and an HMI terminal 30 (hereinafter referred to as HMI terminal 30b) paired with the communication tag 10b. Moreover, in FIG. 1, the case where the vehicle 3 is drive | working the place 100 meters-several hundred meters away from the pedestrian 1a is illustrated. The vehicle 3 is equipped with an in-vehicle transceiver 5 and the like. First, a configuration example of the communication tag 10 will be described.

  FIG. 2 is a block diagram illustrating a configuration example of the communication tag 10. As shown in FIG. 2, the communication tag 10 includes a terminal-to-terminal short-range wireless communication unit (hereinafter referred to as a short-range wireless communication unit) 11, a medium-range wireless communication unit (that is, a tag communication unit) 13, and a GPS (Global Positioning System) module 15, control unit 50, storage unit 17, count unit 19, power supply control circuit 21, battery 23, charge / discharge control circuit 25, indicator 27, main power switch 29, Have.

  The short-range wireless communication unit 11 transmits and receives data using a short-range wireless communication method (hereinafter referred to as short-range wireless communication) between terminals such as Bluetooth and Zigbee. An antenna 12 is connected to the short-range wireless communication unit 11. The communicable range (that is, communication distance) of the short-range wireless communication unit 11 is, for example, several meters to several tens of meters. The short-range wireless communication unit 11 is connected to another communication tag (hereinafter also referred to as the same type tag) having the same function as the communication tag (ie, self) by short-range wireless communication such as Bluetooth or Zigbee. be able to. The short-range wireless communication unit 11 can be connected to the HMI terminal 30 by short-range wireless communication such as Bluetooth or Zigbee.

  The mid-range wireless communication unit 13 transmits and receives data using a mid-range wireless communication method (hereinafter referred to as “medium-range wireless communication”) such as RFID (Radio Frequency IDentification). Medium-range wireless communication is also called tag communication. An antenna 14 is connected to the mid-range wireless communication unit 13. The communication distance of the mid-range wireless communication unit 13 is, for example, 100 meters to several hundred meters. The mid-range wireless communication unit 13 can be connected to the in-vehicle transmitter / receiver 5 mounted on the vehicle 3 by mid-range radio communication, for example.

  In the short-range wireless communication unit 11 and the medium-range wireless communication unit 13 described above, the power required for data transmission / reception is obtained from the battery 23 instead of the induced electromotive force. Thereby, the short-range wireless communication unit 11 and the medium-range wireless communication unit 13 can stably transmit and receive data without depending on the external magnetic field environment. In addition, the medium-range wireless communication unit 13 can achieve a communication distance of a relatively medium to long distance in tag communication, such as 100 meters to several hundred meters, by receiving power supply from the battery. Note that the mid-range radio communication by the mid-range radio communication unit 13 has a longer communication distance than the short-range radio communication by the short-range radio communication unit 11. For this reason, the mid-range wireless communication unit 13 consumes more energy (electric power) in the communication process than the short-range wireless communication unit 11.

The GPS module 15 periodically detects its current position using a satellite positioning system. Further, when the GPS module 15 is moving, the GPS module 15 periodically detects the moving speed and moving direction. An antenna 16 is connected to the GPS module 15 and receives a signal transmitted from a satellite.
The control unit 50 is connected to each of the short-range wireless communication unit 11, the medium-range wireless communication unit 13, the GPS module 15, the storage unit 17, the count unit 19, the indicator 27, the power supply control circuit 21, and the charge / discharge control circuit 25. . The control unit 50 acquires various types of information from the short-range wireless communication unit 11, the medium-range wireless communication unit 13, the GPS module 15, the charge / discharge control circuit 25, and the like. And based on this acquired information, the control part 50 performs various processes. In order to execute these various processes, the control unit 50, for example, as shown in FIG. 3, for example, the movement state detection unit 51, the communication tag detection unit 53, the transmission cycle adjustment unit 55, and the reception cycle adjustment unit 57. A vehicle detection unit 59, a vehicle approach determination unit 61, and an information exchange unit 63. The control unit 50 is configured by a logic circuit such as a CPU, for example.

The storage unit 17 stores (stores) information acquired by the control unit 50. The storage unit 17 is configured by, for example, a flash memory. The count unit 19 measures time. The count unit 19 is configured by a circuit in which flip-flops are connected in multiple stages, for example.
The power supply control circuit 21 supplies power to the short-range wireless communication unit 11, the medium-range wireless communication unit 13, and the GPS module 15. The battery 23 is a power source for the communication tag 10. The battery 23 is charged from an external power source via the charge / discharge control circuit 25. The charge / discharge control circuit 25 maintains the stored amount (voltage) of the battery 23 between a preset upper limit value and lower limit value, and prevents overcharge and overdischarge. The indicator 27 displays its own communication state and the remaining battery level on the outside. The main power switch 29 is a switch that is turned on and off by a pedestrian (user) operation. When the main power switch 29 is turned on, the charge / discharge control circuit 25 operates, and predetermined power is supplied from the battery 23 to the power control circuit 21.

Next, processing of the communication tag 10 according to the first embodiment will be described with reference to FIGS.
FIG. 4 is a flowchart (main routine) showing processing of the communication tag 10 according to the first embodiment. Here, a process executed by the communication tag 10a will be described.
In step (S) 11 of FIG. 4, the GPS module 15 acquires its current position based on a signal transmitted from a satellite. In addition, when the GPS module 15 is moving (that is, when the current position changes with time), the GPS module 15 acquires the moving speed and the moving direction together with the current position. In step (S) 12, information about the position measured in step (S) 11 (that is, positioning information) is output from the GPS module 15. The output positioning information is stored in the storage unit 17.

In step (S) 13, the movement state detection unit 51 shown in FIG. 3 reads the positioning information stored in the storage unit 17. And the movement state detection part 51 calculates the movement amount per preset time (for example, 1 minute) based on this read positioning information.
In step (S) 14, the movement state detection unit 51 determines whether or not the pedestrian 1a carrying the communication tag 10a is in a walking state based on the calculated movement amount. If an example is given, the movement state detection part 51 will determine with a walking state, when the movement amount computed by step (S) 13 exists in the range of 20 meters-200 meters per minute. Moreover, the movement state detection part 51 determines that it is not a walking state (namely, non-walking state), when the moving amount calculated by step (S) 13 is outside the range of 20 meters-200 meters per minute. .

If it is determined in step (S) 14 that the user is in the walking state, the process proceeds to step (S) 15. If it is determined in step (S) 14 that the vehicle is not walking, the process proceeds to step (S) 19. In step (S) 16, a search for the same type tag via the short-range wireless communication unit 11 and a setting process for medium-range wireless communication based on the search result are performed.
FIG. 5 is a flowchart (subroutine) showing the processing content of step (S) 15. In step (S) 31 of FIG. 5, the count unit 19 starts measuring time from zero (0). In step (S) 32, the short-range wireless communication unit 11 starts short-range wireless communication such as Bluetooth or Zigbee. In step (S) 33, the communication tag detection unit 53 searches for the same type tag via the short-range wireless communication unit 11. That is, under the control of the communication tag detection unit 53, the short-range wireless communication unit 11 attempts to receive short-range wireless communication transmitted from the same type tag. For example, when the same type tag 10b exists around the communication tag 10a (for example, within a range of several meters to several tens of meters), such as Bluetooth, Zigbee, etc. transmitted from the same type tag 10b. Short-range wireless communication is received by the short-range wireless communication unit 11 of the communication tag 10a.

  In step (S) 34, the communication tag detection unit 53 determines the presence or absence of the same type tag. For example, the communication tag detection unit 53 receives the same type tag 10b when short-range wireless communication transmitted from the same type tag 10b is received for a preset time (for example, 1 minute). Is determined to exist around. In addition, the communication tag detection unit 53 does not receive the short-range wireless communication transmitted from the same type tag 10b, or even when it is received, the period is shorter than a preset time (for example, 1 minute). In this case, it is determined that the same type tag 10b does not exist around.

  If it is determined that the same type tag exists in the surroundings, the process proceeds to step (S) 35, and if it is determined that the same type tag does not exist, the process proceeds to step (S) 38. If it is determined that the same type tag exists, information regarding the number of the same type tag is stored in the storage unit 17. For example, when the communication tag detection unit detects only the same type tag 10 b, the number “1” of the same type tag 10 b is stored in the storage unit 17.

In step (S) 35, the transmission cycle adjustment unit 55 reads information related to the number of same-type tags from the storage unit 17. Then, the transmission cycle adjustment unit 55 adjusts the transmission cycle of the medium distance wireless communication by the medium distance wireless communication unit 13 based on the read information. This adjustment can be performed based on the following formula (1), for example.
n <Ts ′ ≦ n × Ts (1)
Ts is a transmission cycle when the same type tag is not detected (hereinafter also referred to as normal time), Ts ′ is a transmission cycle after adjustment, and n is a number obtained by adding self to the number of detected same type tags. is there. In the example shown in FIG. 1, since n = 2 (communication tags 10a and 10b), the transmission cycle Ts' is twice as long as Ts (see FIGS. 7A and 7B described later). ).

Further, in this step (S) 35, the reception cycle of the medium distance wireless communication by the medium distance wireless communication unit 13 is adjusted. In other words, the reception cycle adjustment unit 57 reads information on the number of identical tags from the storage unit 17. Then, the reception cycle adjustment unit 57 adjusts the reception cycle of the medium distance wireless communication by the medium distance wireless communication unit 13 based on the read information. This adjustment can be performed based on the following formula (2), for example.
Tr <Tr ′ ≦ n × Tr (2)
Tr is the normal reception period, Tr ′ is the adjusted reception period, and n is the number of the same type tags detected plus the self. In the example shown in FIG. 1, since n = 2 (communication tags 10a, 10b), the reception cycle Tr ′ is twice as long as Tr (see FIGS. 7A and 7B described later). ).

  In step (S) 36, the mid-range radio communication unit 13 starts mid-range radio communication at the adjusted communication cycle (transmission cycle, reception cycle) Ts ′, Tr ′. In step (S) 37, the count unit 19 stops measuring time. The count value of the count unit 19 is returned to zero. After step (S) 37, the process returns to FIG. In step (S) 38, the mid-range radio communication unit 13 starts mid-range radio communication with the normal communication cycles Ts and Tr.

  In step (S) 16 of FIG. 4, the medium-range wireless communication unit 13 uses the latest positioning information acquired by the GPS module 15 and its own ID information in the transmission cycle Ts ′ set in step (S) 15. And send. This information can be received by the in-vehicle transmitter / receiver 5 of the vehicle 3 that is traveling within the communicable range of the mid-range wireless communication unit 13. In step (S) 17, a reception process in the medium-range wireless communication unit 13 and a transmission / reception process in the short-range wireless communication unit 11 are performed.

  FIG. 6 is a flowchart (subroutine) showing the processing content of step (S) 17. In step (S) 51 of FIG. 6, the vehicle detection unit 59 is measured by the ID information of the vehicle 3 and the GPS information of the vehicle 3 (that is, the GPS module mounted on the vehicle) via the medium-range wireless communication unit 13. In addition, it is determined whether or not the position information of the vehicle 3 has been received. When it is determined that the ID information and GPS information of the vehicle 3 have been received, the process proceeds to step (S) 52, and when it is determined that the vehicle has not received the ID information and GPS information, the process proceeds to step (S) 56. In addition, when it determines with having received ID information and GPS information of the vehicle 3, those information is stored in the memory | storage part 17. FIG.

In step (S) 52, the vehicle approach determination unit 61 determines whether or not the vehicle 3 is approaching itself from its own positioning information and the GPS information of the vehicle 3. When it is determined that the vehicle 3 is approaching itself, the process proceeds to step (S) 53, and when it is determined that the vehicle 3 is not approaching, the process proceeds to step (S) 56.
In step (S) 53, the vehicle approach determination unit 61 determines whether or not the expected arrival time until the vehicle 3 reaches itself is equal to or less than a preset time (for example, 10 seconds). Or the vehicle approach determination part 61 determines whether the distance between a vehicle and self is below a preset distance (for example, 100 meters). If it is determined that the time or distance is 10 seconds or 100 meters or less, for example, the process proceeds to step (S) 54, and if it is determined that the value exceeds 10 seconds or 100 meters, step (S ) Go to 56.

  In step (S) 54, the information exchanging unit 63 provides the approach information of the vehicle 3 to the same type tag 10b existing in the vicinity via the short-range wireless communication unit 11. In step (S) 55, the short-range wireless communication unit 11 notifies the approach of the vehicle 3 to the pedestrian 1a through the HMI terminal 30a paired with the communication tag 10a (that is, set for connection). After step (S) 55, the process returns to FIG.

In step (S) 56, the vehicle approach determination unit 61 determines whether or not the approach information of the vehicle 3 has been received from the surrounding same type tag via the short-range wireless communication unit 11. If it is determined that it has been received, the process proceeds to step (S) 55. On the other hand, if it is determined that it has not been received, the process returns to FIG.
In step (S) 18 of FIG. 4, it is determined whether the main power switch 29 is on or off.
If the main power switch 29 is kept on, the process returns to step (S) 11. Further, when the main power switch 29 is turned off by the operation of the pedestrian 1a or the like, the processing of the communication tag 10 shown in FIG. 4 is ended.

  FIGS. 7A to 7C are diagrams illustrating an example of transmission periods Ts and Ts ′ and reception periods Tr and Tr ′ of medium-range wireless communication. As shown in FIG. 7, by adjusting the transmission cycle Ts of the medium-range wireless communication to Ts ′ or adjusting the reception cycle Tr of the medium-range wireless communication to Tr ′, Power consumption can be reduced.

(Operation)
Next, an operation example of the first embodiment will be described. Here, the case shown in FIG. 1 is assumed for easy understanding of the operation example. That is, the pedestrian 1a carries the communication tag 10a and the HMI terminal 30a. There is another pedestrian 1b around the pedestrian 1a. Furthermore, the case where the vehicle 3 equipped with the vehicle-mounted transceiver 5 is traveling in a place that is a hundred meters to several hundred meters away from the pedestrians 1a and 1b.
First, the GPS module 15 of the communication tag 10a repeatedly acquires its current position after a certain period of time. Information on the current position is read to the control unit 50 via the storage unit 17. Based on the read information, the control unit 50 determines whether or not its own moving state corresponds to a walking state.

When the movement state of the user corresponds to the walking state, the control unit 50 repeatedly searches for the same type tag after a certain period of time via the short-range wireless communication unit 11. When the same type tag is detected by this search, the transmission cycle and the reception cycle of the medium distance wireless communication by the medium distance wireless communication unit 13 are adjusted. For example, when the detected same type tag is only the communication tag 10b, since the number of detection is one, as shown in FIGS. 7A and 7B, the transmission cycle Ts and the reception cycle Tr are set respectively. Adjustment is made to Ts ′ and Tr ′ corresponding to twice the period. In the medium-range wireless communication unit 13, the length of the transmission mode (that is, the transmission time per time) and the length of the reception mode (that is, the reception time per time) are the same before and after the adjustment. The value shall be maintained. The length of the reception mode is sufficiently longer than the length of the transmission mode.
Thus, after the communication cycle of the medium distance wireless communication is adjusted, the medium distance wireless communication unit 13 transmits its own ID information and positioning information. The transmitted ID information and positioning information of the communication tag 10a are received by the in-vehicle transceiver 5 on which the vehicle 3 is mounted.

  FIG. 8 is a diagram illustrating an example of the monitor screen 7 mounted on the vehicle 3. A monitor screen 7 shown in FIG. 8 is a part of a car navigation system mounted on the vehicle 3, for example, and displays the position of the pedestrian 1a together with a map. In addition, this car navigation system may notify the driver of the presence of a pedestrian by voice from a speaker in combination with the display on the monitor screen 7 (or separately from the display on the monitor screen 7). The notification content includes, for example, a predicted arrival time until the vehicle 3 reaches the pedestrian 1a, a distance between the pedestrian 1a and the vehicle 3, and the like. As a result, the driver of the vehicle 3 indicates that the pedestrian 1a is present in the traveling direction of the vehicle 3 (for example, when going straight or straight, when turning right, when turning right, when turning left, when turning left). I can know.

On the other hand, the mid-range wireless communication unit 13 acquires the ID information of the vehicle 3 and the GPS information of the vehicle 3 transmitted from the in-vehicle transceiver 5. The control unit 50 determines whether or not the vehicle 3 is approaching itself based on the GPS information of the vehicle 3 and its own GPS information.
When the vehicle 3 is approaching, an expected arrival time until the vehicle 3 reaches itself (or a distance between the vehicle 3 and itself) is calculated. When this time (or distance) is equal to or less than a preset value, the short-range wireless communication unit 11 transmits approach information of the vehicle 3 to the same type tag 10b existing around. The short-range wireless communication unit 11 notifies the pedestrian 1a of the approach of the vehicle 3 through the HMI terminal 30a paired with the communication tag 10a. The notification content includes, for example, a predicted arrival time until the vehicle 3 reaches the pedestrian 1a, a distance between the pedestrian 1a and the vehicle 3, and the like.

The same type tag 10b notified of the approach information of the vehicle 3 notifies the pedestrian 1b of the approach of the vehicle 3 through the HMI terminal 30b paired with the same type tag 10b.
FIG. 9 is a diagram illustrating an example of the HMI terminal 30. As shown in FIG. 9, the HMI terminal 30 may display on which screen the vehicle 3 is approaching. Furthermore, the HMI terminal 30 may sound a buzzer from a built-in speaker, vibrate the terminal itself, or blink an indicator such as an LED (light emitting diode) as the vehicle 3 approaches. In this case, the HMI terminal 30a may gradually increase the volume, gradually vibrate strongly, or gradually shorten the blinking interval according to the distance to the vehicle 3 and the estimated arrival time. Thereby, the pedestrian 1a can know the approach of the vehicle 3 via the HMI terminal 30a even when the vehicle 3 approaches the scale from the rear.

  In the first embodiment and the second to fifth embodiments described later, the short-range wireless communication corresponds to the first wireless communication method, and the short-range wireless communication unit 11 corresponds to the first wireless communication means. Yes. The GPS module 15 corresponds to position information acquisition means. The medium distance wireless communication corresponds to the second wireless communication method, and the medium distance wireless communication unit 13 corresponds to the second wireless communication means. Moreover, the communication tag detection part 53 respond | corresponds to a communication tag detection means. The transmission cycle adjustment unit 55 corresponds to transmission cycle adjustment means. The reception cycle adjustment unit 57 corresponds to reception cycle adjustment means. The vehicle detection unit 59 corresponds to vehicle detection means. The vehicle approach determination unit 61 corresponds to a vehicle approach determination unit. The information exchange unit 63 corresponds to information exchange means. Furthermore, the in-vehicle transceiver 5 corresponds to the receiving means of the in-vehicle device. The monitor screen 7 corresponds to the display means of the in-vehicle device. Further, the transmission cycle Ts corresponds to the first transmission cycle, and the adjusted transmission cycle Ts ′ corresponds to the second transmission cycle. The reception cycle Tr corresponds to the first reception cycle, and the adjusted reception cycle Tr ′ corresponds to the second reception cycle.

(Effect of 1st Embodiment)
The first embodiment has the following effects.
(1) The transmission cycle adjustment unit 55 of the communication tag 10 adjusts the transmission cycle of the medium-range wireless communication based on the detection result of another communication tag (that is, the same type tag) having the same function as itself (step) (S) 35). When the communication tag 10a detects the same type tag, the transmission period Ts of the communication tag 10a is adjusted to a longer period Ts ′. For this reason, the communication tag 10a can suppress battery consumption.
(2) The reception cycle adjustment unit 57 of the communication tag 10 adjusts the reception cycle of the medium-range wireless communication based on the detection result of the same type tag (step (S) 35). When the communication tag 10a detects the same type tag, the reception cycle Tr of the communication tag 10a is adjusted to a longer cycle Tr ′. For this reason, the communication tag 10a can suppress battery consumption.
(3) As shown in FIGS. 7B and 7C, when the communication tag 10a transmits its own position information by medium-range wireless communication, the communication tag 10b, which is the same type tag, also has its own position information. Is transmitted by mid-range wireless communication.
Here, when the communication tags 10a and 10b exist in a narrow range (several meters to several tens of meters) in which short-range wireless communication can be performed, the vehicle 3 far away from the communication tags 10a and 10b. From the driver, the communication tags 10a and 10b seem to be present at substantially the same position. Accordingly, the communication tags 10a and 10b can share the position information transmission process for the vehicle. The communication tags 10a and 10b can share the transmission processing of the medium distance wireless communication so as to suppress the battery consumption.

(4) The mid-range wireless communication unit 13 acquires, for example, position information of the vehicle 3 traveling 100 meters to several hundred meters ahead (step (S) 51). The vehicle detection unit 59 determines whether or not the vehicle 3 is approaching to itself based on the position information of the vehicle 3 and its own position information (step (S) 52). And when it determines with the vehicle 3 approaching, the short distance radio | wireless communication part 11 transmits the approach information of the vehicle 3 by short distance radio | wireless communication, such as Bluetooth and Zigbee (step (S) 54). Moreover, the communication tag 10 can also receive the approach information of the vehicle 3 from the same type tag by short-range wireless communication (step (S) 56).
For example, the approach information of the vehicle 3 can be provided to each other by short-range wireless communication between the communication tag 10a and the same type tag 10b. For this reason, it is possible to share the reception process of the mid-range wireless communication for acquiring the ID information and GPS information of the vehicle 3 between the communication tag 10a and the same type tag 10b.

(5) The transmission cycle adjustment unit 55 and the reception cycle adjustment unit 57 adjust the transmission cycle and the reception cycle of the mid-range wireless communication when the same type tag is detected for a predetermined time (steps (S) 14 and 15). ). Thereby, the communication tag 10 shares the transmission process and the reception process of the medium-distance wireless communication with the same type tag that stays within a predetermined distance range (for example, within a range of several tens of meters) from the self for a predetermined time or more. Can do.
(6) The transmission cycle adjustment unit 55 and the reception cycle adjustment unit 57 adjust the transmission cycle and the reception cycle of medium-range wireless communication based on the number of the same type tags detected by the communication tag detection unit 53, respectively (step) (S) 35). As the detected number of the same type tag is larger, the transmission process and the reception process of the mid-range wireless communication can be shared more widely and shallowly. Thereby, the communication tag 10 can further suppress battery consumption.

(7) The movement state detection unit 51 detects its own movement state based on its own positioning information acquired by the GPS module 15 (steps (S) 13, 14). The medium distance wireless communication unit 13 stops the medium distance wireless communication when the detected movement state of the self does not correspond to the walking state (step (S) 19). That is, the communication tag 10 stops the middle-range wireless communication when it is estimated that the pedestrian is not walking. Thereby, battery consumption can be further suppressed.
(8) After stopping the medium distance wireless communication, the medium distance wireless communication unit 13 starts the medium distance wireless communication when the movement state of the medium distance wireless communication unit 13 corresponds to the walking state (step (S)). 14). That is, the communication tag 10 resumes the mid-range wireless communication when it is estimated that the pedestrian has resumed walking. Thereby, the communication tag 10 can notify the driver of the vehicle 3 again of the presence of a pedestrian.

(Modification)
(1) In said 1st Embodiment, as shown to Fig.7 (a) and (b), the case where the transmission period and reception period of medium distance radio | wireless communication were each adjusted was illustrated. However, in the present embodiment, it is possible to adjust only the cycle of the transmission process in which the battery consumption is relatively large even in the middle-range wireless communication.
That is, in step (S) 35 in FIG. 5, only the transmission cycle of the medium-range wireless communication may be adjusted. For example, as shown in FIG. 10, only the transmission cycle Ts is changed to Ts ′ without changing the reception cycle Tr. Even in such a case, the communication tag 10 can share the transmission processing of the mid-range wireless communication with the same type tag, and can suppress battery consumption.

(2) In the first embodiment, as illustrated in FIG. 1, the case where the communication tag 10 b exists as the same type tag in the short-range wireless communication area of the communication tag 10 a is illustrated. However, in the present embodiment, the same type tag existing in the short-range wireless communication area is not limited to the communication tag 10b. For example, as shown in FIG. 11, the same type tags 10b to 10d may exist as the same type tags in the short-range wireless communication area.
That is, other pedestrians 1b to 1d may exist around the pedestrian 1a. These pedestrians 1b to 1d may carry the same type tags 10b to 10d and the HMI terminals 30b to 30d paired with the same type tags 10b to 10d, respectively. In such a case, n = 4 in the above equation (1). For this reason, the transmission cycle Ts ′ after the adjustment of the communication tag 10a can be set to a length that is four times the maximum of the normal transmission cycle Ts. Further, the reception cycle Tr ′ after adjustment of the communication tag 10a can be set to a length that is four times the maximum of the normal reception cycle Tr.

(3) Further, the communication tag 10a described above may search the timing at which the same type tags 10b to 10d are not transmitting information in its own reception mode. And the communication tag 10a may be made to transmit own positional information by medium distance radio | wireless communication at the timing which the same type tags 10b-10d are not transmitting information. For example, in the CSMA (Carrier Sense Multiple Access / Collision Detection) method, the communication tags 10a to 10d may transmit the respective position information by medium-range wireless communication.
As a result, the communication tags 10a to 10d can transmit their own position information through medium-range wireless communication while preventing collision of transmission data and interference with each other.

(4) Alternatively, the communication tags 10a to 10d may temporarily extend (or shorten) the length of the transmission mode or the length of the reception mode at an arbitrary timing. For example, the reception mode having a normal length of 10 seconds is temporarily extended to 15 seconds at an arbitrary timing. Thereby, since the timing of the transmission mode is randomly shifted, it is possible to prevent the collision of transmission data and interference between the communication tags 10a to 10d.
(5) Moreover, in said 1st Embodiment, the case where a pedestrian carries the communication tag 10 and the presence of a pedestrian is notified to a vehicle via this communication tag 10 illustrated. However, in this embodiment, the communication tag 10 is not limited to being carried by a pedestrian. For example, the communication tag 10 may be attached to an obstacle or luggage on a road. In such a case, the vehicle is notified of the presence of obstacles, luggage, etc. on the road via the communication tag 10.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings. In the second embodiment, parts having the same configuration as in the first embodiment will be described with the same reference numerals. In the first embodiment, an example has been described in which the communication cycle of medium-range wireless communication is adjusted based on the number of detected same-type tags. In the second embodiment, an example will be described in which the communication cycle of medium-range wireless communication is adjusted based on information related to the remaining battery level (that is, remaining battery level information).
(Constitution)
FIG. 12 is a flowchart (subroutine) showing the processing content of step (S) 15 of the communication tag 10 according to the second embodiment. In the second embodiment, part of the processing content of step (S) 15 is different from that of the first embodiment. The other configuration is the same between the first embodiment and the second embodiment. Therefore, here, the processing content of step (S) 15 will be described.

Steps (S) 31 to 34 in FIG. 5 are the same as those in the first embodiment. If it is determined in step (S) 34 that the same type tag exists in the vicinity, the process proceeds to step (S) 41.
In step (S) 41, the information exchange unit 63 exchanges the same type tag and battery remaining amount information via the short-range wireless communication unit 11. That is, the information exchange unit 63 acquires the remaining amount information of the same type tag via the short-range wireless communication unit 11. Further, the information exchange unit 63 provides battery remaining amount information of the communication tag 10 (self) via the short-range wireless communication unit 11. The remaining amount information of the same type tag acquired by the communication tag detection unit 53 and its own battery information are stored in the storage unit 17.

In step (S) 42, the transmission cycle adjustment unit 55 reads out the remaining battery information from the storage unit 17. Then, the transmission cycle adjustment unit 55 adjusts the transmission cycle of the medium distance wireless communication by the medium distance wireless communication unit 13 based on the read information. This adjustment can be performed based on the following formula (3), for example.
Ts <Ts ′ ≦ (Qa + ΣQn) / Qa × Ts (3)
Qa is a remaining battery level value of the communication tag 10a, and ΣQn is a sum of detected remaining battery level values of the same type tag.

In the example shown in FIG. 1, the same type tag that exists around the communication tag 10a is only the communication tag 10b. For this reason, in the example shown in FIG. 1, Formula (3) is represented by Formula (3) ′.
Ts <Ts ′ ≦ (Qa + Qb) / Qa × Ts (3) ′
Qb is a remaining battery value of the same type tag 10b. As an example, when the battery remaining value Qb of the same type tag 10b is twice the own battery remaining value Qa, the expression (3) ′ is calculated as follows.
Ts ′ ≦ (Qa + Qb) / Qa × Ts
≦ (Qa + 2Qa) / Qa × Ts
≦ 3 × Ts
In other words, the adjusted transmission cycle Ts ′ is three times as much as the pre-adjustment transmission cycle Ts.

Similarly, the reception cycle adjustment unit 57 reads battery remaining amount information from the storage unit 17. Then, the reception cycle adjustment unit 57 adjusts the reception cycle of the medium distance wireless communication by the medium distance wireless communication unit 13 based on the read information. This adjustment can be performed based on the following formula (4), for example.
Tr <Tr ′ ≦ (Qa + ΣQn) / Qa × Tr (4)
Qa is a remaining battery level value of the communication tag 10a, and ΣQn is a sum of detected remaining battery level values of the same type tag.

In the example shown in FIG. 1, the same type tag that exists around the communication tag 10a is only the communication tag 10b. For this reason, in the example shown in FIG. 1, Formula (4) is represented by Formula (4) ′.
Tr <Tr ′ ≦ (Qa + Qb) / Qa × Tr (4) ′
Qb is a remaining battery value of the same type tag 10b. As an example, when the remaining battery level value Qb of the same type tag 10b is twice the own remaining battery level value Qa, the equation (4) ′ is calculated as follows.
Tr ′ ≦ (Qa + Qb) / Qa × Tr
≦ (Qa + 2Qa) / Qa × Tr
≦ 3 × Tr
That is, the adjusted reception cycle Tr ′ is three times the maximum of the reception cycle Tr before adjustment.
The subsequent processing is the same as in the first embodiment. That is, in step (S) 36, the mid-range radio communication unit 13 starts mid-range radio communication at the adjusted communication cycles Ts ′ and Tr ′. In step (S) 37, the count unit 19 stops measuring time. Thereafter, the process returns to FIG. Other configurations are the same as those in the first embodiment.

(Operation)
Next, an operation example of the second embodiment will be described. As in the first embodiment, the case shown in FIG. 1 is assumed for easy understanding of the operation example.
First, the GPS module 15 of the communication tag 10a repeatedly acquires its current position after a certain period of time. Information on the current position is read to the control unit 50 via the storage unit 17. Based on the read information, the control unit 50 determines whether or not its own moving state corresponds to a walking state.

When the movement state of the user corresponds to the walking state, the control unit 50 repeatedly searches for the same type tag after a certain period of time via the short-range wireless communication unit 11. When the same type tag is detected by this search, the transmission cycle and the reception cycle of the medium distance wireless communication by the medium distance wireless communication unit 13 are adjusted.
When the detected same type tag is only the communication tag 10b, battery information is exchanged with the same type tag 10b. Then, as shown in the equations (3) ′ and (4) ′, based on the ratio of the own battery remaining amount value Qa and the remaining battery amount value Qb of the same type tag 10b, the own transmission cycle Ts and The reception cycle Tr is adjusted. For example, in the case of Qa: Qb = 1: 2, as calculated above, the transmission cycle Ts and the reception cycle Tr are adjusted to Ts ′ and Tr ′ corresponding to three times the cycle, respectively. The subsequent operations are the same as those in the first embodiment.

(Effect of 2nd Embodiment)
The second embodiment has the following effects in addition to the effects of the first embodiment.
The transmission cycle adjustment unit 55 and the reception cycle adjustment unit 57 respectively adjust the transmission cycle and the reception cycle of the medium-range wireless communication based on the battery remaining amount information of the same type tag detected by the communication tag detection unit 53 (step) (S) 41, 42). As the remaining battery level is lower, the transmission cycle and the reception cycle can be lengthened, and the burden of communication processing can be reduced. Thereby, the communication tag 10 can reduce the possibility of running out of battery before charging.

(Modification)
Also in the second embodiment, as shown in FIG. 11, for example, more same-type tags 10b to 10d may exist in the short-range wireless communication area of the communication tag 10a. When the same type tags 10b to 10d are detected in the short-range wireless communication area of the communication tag 10a, the above equation (3) is expressed by equation (3) ″.
Ts <Ts ′ ≦ (Qa + Qb + Qc + Qd) / Qa × Ts (3) ″
Qc is the remaining battery level value of the communication tag 10c, Qd is the remaining battery level value of the communication tag 10d, and Qe is the remaining battery level value of the communication tag 10e. As an example, the battery remaining value Qb of the communication tag 10b is twice the own battery remaining value Qa, and the battery remaining value Qc of the communication tag 10c is 0.5 times the own battery remaining value Qa. When the remaining battery level value Qd of the communication tag 10d is 1.5 times its own remaining battery level value Qa, equation (3) ′ is calculated as follows.
Ts ′ ≦ (Qa + Qb + Qc + Qd) / Qa × Ts
≦ (Qa + 2Qa + 0.5Qa + 1.5Qa) / Qa × Ts
≦ 5 × Tr
That is, the reception cycle Tr ′ can be set to 5 times the reception cycle Tr at the maximum.

Similarly, the above equation (4) is expressed by equation (4) ″.
Tr <Tr ′ ≦ (Qa + Qb + Qc + Qd) / Qa × Tr (4) ″
When Qb is 2 times, Qc is 0.5 times, and Qd is 1.5 times compared to Qa, Equation (4) ″ is calculated as follows.
Tr ′ ≦ (Qa + Qb + Qc + Qd) / Qa × Tr
≦ (Qa + 2Qa + 0.5Qa + 1.5Qa) / Qa × Tr
≦ 5 × Tr
That is, the reception cycle Tr ′ can be set to 5 times the reception cycle Tr at the maximum.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to the drawings. In the third embodiment, parts having the same configurations as those in the above embodiments will be described with the same reference numerals.
1st Embodiment demonstrated the case where the movement state detection part 51 determined whether the pedestrian 1a carrying the communication tag 10a was in a walking state based on the positioning information by the GPS module 15 ( Step (S) 14). In the third embodiment, an example in which the moving state detection unit 51 determines whether or not the pedestrian 1a carrying the communication tag 10a is in the vehicle after step (S) 14 will be described. To do.

(Constitution)
FIG. 13 is a flowchart (main routine) showing processing of the communication tag 10 according to the third embodiment. In the third embodiment, a step (S) 21 is newly provided between step (S) 14 and step (S) 15 as compared with the first embodiment. Other configurations are the same as those in FIG. 4 described in the first embodiment. Therefore, here, the processing content of step (S) 21 will be described.
In step (S) 21 of FIG. 13, the movement state detection unit 51 determines whether or not short-range wireless communication (for example, a signal from the in-vehicle Bluetooth device) output from the in-vehicle device is detected. This detection is performed for a preset time (for example, 1 minute) via the short-range wireless communication unit 11. Note that it is possible to determine whether or not the detected Bluetooth signal is a signal output from the in-vehicle device based on profile information included in this signal. For example, if the profile of the detected Bluetooth signal is HFP, it can be determined that this signal is a signal output from the in-vehicle device.

  If it is determined in step (S) 21 that the in-vehicle Bluetooth signal is detected, it is determined that the pedestrian 1a is in the vehicle 3 or in a vehicle other than the vehicle 3. In this case, the process proceeds to step (S) 19 and the operation of the intermediate-range wireless communication unit 13 is stopped. On the other hand, if it is determined in step (S) 21 that a signal from the in-vehicle Bluetooth device is not detected, the process proceeds to step (S) 15. Other configurations are the same as those in the first embodiment.

(Operation)
Next, an operation example of the third embodiment will be described. As in the first embodiment, the case shown in FIG. 1 is assumed for easy understanding of the operation example.
First, the GPS module 15 of the communication tag 10a repeatedly acquires its current position after a certain period of time. Information on the current position is read to the control unit 50 via the storage unit 17. Based on the read information, the control unit 50 determines whether or not its own moving state corresponds to a walking state.
When the own movement state corresponds to the walking state, the control unit 50 tries to detect the in-vehicle Bluetooth signal via the short-range wireless communication unit 11. For example, when the in-vehicle Bluetooth signal is detected for one minute, it is determined that the pedestrian 1a is in the vehicle 3 or in another vehicle other than the vehicle 3. In that case, the operation of the mid-range wireless communication unit 13 is stopped. On the other hand, if the in-vehicle Bluetooth signal is not detected, or even if it is detected, the period is less than 1 minute, for example, the control unit 50 searches for the same type tag via the short-range wireless communication unit 11 for a certain period of time. Repeat this step. The subsequent operations are the same as those in the first embodiment or the second embodiment.

(Effect of the third embodiment)
The third embodiment has the following effects in addition to the effects of the first embodiment or the second embodiment.
(1) If the in-vehicle Bluetooth signal is received for a preset time (for example, 1 minute), the intermediate distance wireless communication unit 13 stops the intermediate distance wireless communication (steps (S) 21 and 19). ). When the in-vehicle Bluetooth signal is received, it is estimated that the pedestrian 1a carrying the communication tag 10a is on the vehicle. For this reason, the mid-range wireless communication unit 13 can stop the communication process and suppress battery consumption.
(2) The intermediate-range wireless communication unit 13 starts the stopped intermediate-range wireless communication according to the reception status of the in-vehicle Bluetooth signal. That is, if the in-vehicle Bluetooth signal is not received, for example, for one minute after stopping the intermediate distance wireless communication, the intermediate distance wireless communication unit 13 starts the intermediate distance wireless communication (steps (S) 21, 15, 16). When the in-vehicle Bluetooth signal is not received, it can be estimated that the pedestrian 1a carrying the communication tag 10a has got off the vehicle. For this reason, the mid-range wireless communication unit 13 starts the communication process.

(Modification)
In said 3rd Embodiment, the case where the movement state detection part 51 determined whether the pedestrian 1a exists in a vehicle based on the vehicle-mounted Bluetooth signal was illustrated. However, in the present embodiment, the movement state detection unit 51 takes into account the positioning information acquired by the GPS module 15 (for example, detection of high-speed movement or no signal reception at all) in the in-vehicle Bluetooth signal. Thus, it may be determined whether or not the pedestrian 1a is in the vehicle. Thereby, the determination precision by the movement state detection part 51 can further be improved.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to the drawings. In addition, in this 4th Embodiment, the same code | symbol is attached | subjected and demonstrated to the part which has the structure similar to said each embodiment.
In the first embodiment, the communication tag 10a has detected the same type tag, and then explained an example in which the communication periods Ts and Tr of the mid-range wireless communication unit 13 are adjusted based on the detected number (step (S)). 35). In the fourth embodiment, after this step (S) 35, the communication tag detection unit 53 checks whether or not the link (connection) between the communication tag 10a and the same type tag is maintained. explain.

(Constitution)
FIG. 14 is a flowchart (subroutine) showing the processing content of step (S) 15 of the communication tag 10 according to the fourth embodiment. In the fourth embodiment, compared with the first embodiment, steps (S) 43 to 46 are newly provided between step (S) 35 and step (S) 36. Other configurations are the same as those in FIG. 5 described in the first embodiment. Therefore, here, the processing contents of steps (S) 43 to 46 will be described.
In step (S) 43 of FIG. 14, the communication tag detection unit 53 checks whether or not the connection by the short-range wireless communication between the communication tag 10a (self) and the same type tag is maintained. Specifically, the short-range wireless communication unit 11 transmits a search (scan) signal. The communication tag detection unit 53 checks whether or not the same type tag transmits a response signal in response to the search signal. If a response signal is transmitted from the same type tag, since the connection is maintained, the process proceeds to step (S) 36.

  On the other hand, when the response signal is not transmitted from the same type tag, the connection is not maintained. That is, the so-called link is broken between the communication tag 10a and the same type tag. In this case, the process proceeds to step (S) 44. In step (S) 44, the medium-range wireless communication unit 13 changes the reception cycle from Tr ′ to Tr while maintaining the adjusted transmission cycle Ts ′ as shown in FIG. 10, for example. That is, the mid-range wireless communication unit 13 maintains the sharing with the same type tag for the transmission cycle and cancels the sharing with the same type tag for the reception cycle and changes it at the normal time. The mid-range wireless communication unit 13 starts operation at the standby communication cycles Ts ′ and Tr adjusted as described above. As a result, the communication tag 10a can be prepared for reconnection with the same type tag while saving power in the mid-range wireless communication unit 13.

  In step 45, the short-range wireless communication unit 11 tries to reconnect with the same type tag. This trial is repeated for a preset time (for example, 1 minute). In step 46, the communication tag detection unit 53 confirms whether or not the connection with the same type tag has been recovered. If the connection is recovered, the process proceeds to step 36, and if the connection is not recovered, the process proceeds to step (S) 38. Other configurations are the same as those in the first embodiment.

(Operation)
Next, an operation example of the fourth embodiment will be described. As in the first embodiment, the case shown in FIG. 1 is assumed for easy understanding of the operation example.
First, the GPS module 15 of the communication tag 10a repeatedly acquires its current position after a certain period of time. Information on the current position is read to the control unit 50 via the storage unit 17. Based on the read information, the control unit 50 determines whether or not its own moving state corresponds to a walking state.
When the movement state of the user corresponds to the walking state, the control unit 50 repeatedly searches for the same type tag after a certain period of time via the short-range wireless communication unit 11. When the same type tag is detected by this search, the transmission cycle and the reception cycle of the medium distance wireless communication by the medium distance wireless communication unit 13 are adjusted.

After this adjustment, the control unit 50 checks whether or not the connection by the short-range wireless communication between the communication tag 10a (self) and the same type tag is maintained. When this connection is disconnected, the control unit 50 changes the reception cycle to the normal reception cycle Tr while maintaining the transmission cycle of the medium-range wireless communication at the adjusted transmission cycle Ts ′. The mid-range wireless communication unit 13 starts operation in the standby communication periods Ts ′ and Tr adjusted as described above.
After that, when the connection between the communication tag 10a and the same type tag is not recovered, the control unit 50 changes the transmission cycle of the medium-range wireless communication to the normal transmission cycle Ts. On the other hand, when the connection between the communication tag 10a and the same type tag is recovered, the control unit 50 changes the reception cycle of the medium-range wireless communication to the adjusted reception cycle Tr ′. The subsequent operations are the same as those in the first embodiment.

(Effect of 4th Embodiment)
In addition to the effects of the first to third embodiments, the fourth embodiment has the following effects.
When the same type tag is detected, the transmission cycle adjustment unit 55 changes the transmission cycle from Ts to Ts ′. The reception cycle adjustment unit 57 changes the reception cycle from Tr to Tr ′. Ts <Ts ′ and Tr <Tr ′ (step (S) 35).

Next, when the same type tag is no longer detected, the transmission cycle adjustment unit 55 maintains the transmission cycle at Ts ′. The reception cycle adjustment unit 57 changes the reception cycle from Tr ′ to Tr (steps (S) 43 and 44). In this state, the communication tag detection unit 53 tries to detect the same type tag via the short-range wireless communication unit 11 (step (S) 45). If the same type tag is detected again as a result of this trial, the reception cycle adjustment unit 57 changes the reception cycle from Tr to Tr ′ (step (S) 46). On the other hand, when the same type tag is not detected as a result of this trial, the transmission cycle adjusting unit 55 changes the transmission cycle from Ts ′ to Tr (step (S) 46).
As a result, even when the connection with the same type tag is temporarily interrupted, the communication tag 10a can prepare for reconnection with the same type tag while saving power in the mid-range wireless communication unit 13.

(Modification)
Note that the content described in the fourth embodiment may be applied to the second embodiment. That is, as shown in FIG. 15, steps (S) 43 to 46 may be added after step (S) 42. Also in this case, the communication tag 10a can be prepared for reconnection with the same type tag while saving power in the intermediate-range wireless communication unit 13.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to the drawings. In addition, in this 5th Embodiment, the same code | symbol is attached | subjected and demonstrated to the part which has the structure similar to said each embodiment.
In the embodiment of the present invention, the communication tag 10a may exchange information with the same type tag via short-range wireless communication. As this exchange information, information on the ID of the communication tag, information on the number (number) of detected communication tags, remaining battery information, information on the communication cycle, information on the transmission mode time (timing), position information between communication tags Etc.

  For example, the communication distance of short-range wireless communication is normally about 10 meters. However, the communication distance is not necessarily constant due to the influence of the surrounding environment (radio wave reflecting structure or shielding object), and there is a possibility that the radio wave may reach unexpectedly far (for example, 100 meters or more). . However, if the inter-communication tag position information is included in the exchange information, the communication tag 10a determines that the medium-distance wireless communication partner is the same type tag existing within a range of several tens of meters based on the exchange information. It can be limited.

  In addition to the above, pedestrian type information can be given as exchange information. For example, information such as “infant”, “children (elementary school students)”, “elderly people”, “handicapped (hearing, visual impairment, etc.)” is recorded in the communication tag. Thereby, the communication tag 10a can transmit its pedestrian type information and the pedestrian type information of the other party of the medium distance wireless communication to the vehicle 3 by the medium distance wireless communication. The driver of the vehicle 3 can know the transmitted pedestrian type information by, for example, sound from the monitor screen 7 or a speaker. In the fifth embodiment, a procedure for exchanging such exchange information between communication tags will be described.

(Constitution)
FIGS. 16 to 18B are diagrams schematically illustrating an information exchange method in short-range wireless communication according to the fifth embodiment.
As shown in FIG. 16, each communication tag repeats a parent communication period Tm and a child communication period Tn on each time axis. The parent communication period Tm is divided into a search period Tm1, a connection establishment period Tm2, and an information exchange period Tm3.
In the search period Tm1, the communication tag transmits a search signal by short-range wireless communication. For example, the communication tags 10a and 10g in the parent communication period each transmit a search signal at least once during the search period. As shown in FIG. 17A, when the same type tags 10b, 10c, and 10d exist in the short-distance communication area of the communication tag 10a, the same type tags 10b, 10c, and 10d respond to the search signal. Send. By receiving this response signal, the communication tag 10a recognizes that the same type tags 10b, 10c, and 10d exist in its own short-range communication area.

  Similarly, when the same type tags 10d, 10e, and 10f exist in the short-distance communication area of the communication tag 10g, the same type tags 10d, 10e, and 10f transmit a response signal to the search signal transmitted by the communication tag 10g. To do. By receiving this response signal, the communication tag 10g recognizes that the same type tags 10d, 10e, and 10f exist in its own short-range communication area.

  In the connection establishment period Tm2, the communication tag transmits a signal requesting connection by short-range wireless communication to the same type tag that has transmitted the response signal. For example, the communication tags 10a and 10g in the parent communication period each transmit a connection request signal at least once during the search period. As shown in FIG. 17B, the communication tag 10a transmits a connection request signal to the same type tags 10b, 10c, and 10d that have transmitted the response signal. When the connection is established, the information exchange period Tm3 is reached. In the information exchange period Tm3, information exchange (ie, exchange information transmission / reception) is performed between the communication tag 10a and the same type tags 10b and 10c by short-range wireless communication. As a result, the exchange information can be shared between the communication tag 10a and the same type tags 10b and 10c.

Similarly, the communication tag 10g transmits a connection request signal to the same type tags 10d, 10e, and 10f. When the connection is established, an information exchange period Tm3 is reached, and information is exchanged between the communication tag 10g and the same type tags 10d, 10e, and 10f.
In the example shown in FIGS. 17A and 17B, the communication tag 10d exists near the boundary between the short-range wireless communication area of the communication tag 10a and the short-range wireless communication area of the communication tag 10g. In such a case, the communication tag 10d transmits a response signal to both of the communication tags 10a and 10g. Further, the communication tag 10d is connected to one of the communication tags 10a and 10g, which is a transmission destination of the response signal, and exchanges information. For example, if the communication tag 10d recognizes that the communication tag 10g is closer to the communication tag 10a (or if the connection is established earlier with the communication tag 10g), the communication tag 10d is connected to the communication tag 10g. Exchange information.

  As shown in FIG. 16, when the communication tag 10e in the child communication period is connected to the communication tag 10g in the parent communication period, the communication tag 10e delays (shifts) the time when the parent communication period starts. It may be. That is, the parent communication period of the communication tag 10e may be started after a margin time (+ α) has elapsed since the parent communication period Tm of the communication tag 10g has ended. Thereby, communication tags 10e and 10g can prevent that parent communication time overlaps.

The parent communication period Tm of the communication tag 10g ends, and then a margin time (+ α) elapses, and the parent communication period of the communication tag 10e starts. Then, as shown in FIGS. 18A and 18B, this communication tag 10e also exchanges information with the same type tags 10d, 10f, and 10h existing in its own short-range wireless communication area.
In the communication tags 10a to 10i shown in FIGS. 17 (a) to 18 (b), each information exchange unit 63 transmits and receives a search signal, transmits and receives a connection request signal, and transmits and receives exchange information. This is performed via the communication unit 11. The exchanged information is stored in each storage unit 17.

  FIGS. 19A to 19C are diagrams showing an example of the exchange information recording format. FIG. 19A is an exchange record stored in the storage unit 17 of the communication tag 10a. FIG. 19B is an exchange record stored in the storage unit 17 of the communication tag 10b. FIG. 19C is an exchange record stored in the storage unit 17 of the communication tag 10c. As shown in FIGS. 19A to 19C, each storage unit 17 of the communication tags 10a to 10c stores the ID of the communication tag that has exchanged information, the time when the information exchange is completed, and the contents of the exchange information. Is stored. The information stored in the storage unit 17 is updated every time information is exchanged. The information stored in the storage unit 17 is held for a certain period for each ID of the communication tag. Other configurations are the same as those in the first embodiment.

(Operation)
Next, an operation example according to the fifth embodiment will be described. As in the first embodiment, the case shown in FIG. 1 is assumed for easy understanding of the operation example.
The communication tag 10a carried by the pedestrian 1a becomes the parent communication period Tm. At this time, the communication tag 10a transmits a search signal by short-range wireless communication. When the same type tag 10b exists in the short-range wireless communication area of the communication tag 10a, the same-type tag 10b transmits a response signal by short-range wireless communication. Upon receiving this response signal, the communication tag 10a transmits a connection request signal to the same type tag 10b. Thereby, the same type tag 10b as the communication tag 10a mutually transmits / receives the exchange information which each has by short-distance wireless communication. As a result, the exchange information is shared between the communication tag 10a and the same type tag 10d.

  The shared information is transmitted to the vehicle 3 by the communication tags 10a and 10b through medium-range wireless communication. At this time, the transmission cycle of the medium-range wireless communication is, for example, the adjusted transmission cycle Ts ′ in any of the communication tags 10a and 10b. That is, the shared information is transmitted to the vehicle 3 by the communication tags 10a and 10b sharing the transmission cycle. The shared information is transmitted in, for example, step (S) 16 in FIG. That is, the shared information is transmitted together with its own ID information and GPS positioning information.

  The in-vehicle transceiver 5 receives the transmitted information. The driver of the vehicle 3 can know the received information by, for example, sound from the monitor screen 7 or a speaker. When the information received by the in-vehicle transceiver 5 includes the pedestrian type information of the communication tags 10a and 10b, the information such as “infant”, “child”, “elderly”, and “handicapped” It is displayed as information on the pedestrians 1a and 1b.

(Effect of 5th Embodiment)
In addition to the effects of the first to fourth embodiments, the fifth embodiment has the following effects.
(1) The information exchange unit 63 exchanges information with the same type tag existing in the short-range wireless communication area via the short-range wireless communication unit 11. Thereby, information can be shared among a plurality of communication tags existing in the short-range wireless communication area.
(2) Information exchange by the information exchange unit 63 is performed via the short-range wireless communication unit 11 instead of the medium-range wireless communication unit 13. Thereby, battery consumption can be suppressed.
(3) The mid-range wireless communication unit 13 transmits information (that is, exchange information) obtained by the information exchange unit 63 by mid-range radio communication. Thereby, the exchange information can be provided to the driver of the vehicle 3. For example, the exchange information may include pedestrian type information (for example, information such as “infant”, “children”, “elderly”, and “handicapped”) of the communication tags 10a and 10b. In this case, the driver of the vehicle 3 can know the types of the pedestrians 1a and 1b. When the pedestrians 1a and 1b are infants and children, the driver can pay attention to the possibility that the pedestrians 1a and 1b suddenly start or jump out onto the roadway.

1a to 1d Pedestrian 3 Vehicle 5 Vehicle-mounted transceiver 7 Monitor screen 10 (10a to 10i) Communication tag 11 Short-range wireless communication unit 12, 14, 16 Antenna 13 Medium-range wireless communication unit 15 GPS module 17 Storage unit 19 Count unit 21 Power supply control circuit 23 Battery 25 Charge / discharge control circuit 27 Indicator 29 Main power switch 30b-30d HMI terminal 50 Control unit 51 Movement state detection unit 51 Movement state detection unit 53 Communication tag detection unit 55 Transmission cycle adjustment unit 59 Vehicle detection unit 61 Vehicle Approach determining unit 63 Information exchanging unit 100 Driving support system Tm Parent communication period Tm1 Search period Tm2 Connection establishment period Tm3 Information exchange period Tn Child communication period Tr Reception period Tr 'Reception period Ts after adjustment Transmission period Ts' Transmission period after adjustment

Claims (13)

A communication tag for driving assistance to notify the vehicle of the presence of the vehicle,
First wireless communication means for communicating by a first wireless communication method;
Position information acquisition means for acquiring position information of the communication tag;
Second wireless communication means for transmitting the position information of the communication tag acquired by the position information acquisition means by a second wireless communication method having a communication distance longer than that of the first wireless communication method;
A communication tag detecting means for detecting another communication tag having the same function as the communication tag via the first wireless communication means;
A communication tag for driving assistance, comprising: a transmission period adjusting unit that adjusts a transmission period of the second wireless communication system based on a detection result of the other communication tag. Vehicle detection means for detecting the vehicle via the second wireless communication means;
Whether the vehicle is approaching the communication tag is determined based on the position information of the vehicle detected by the vehicle detection means and the position information of the communication tag acquired by the position information acquisition means. Vehicle approach determining means for
The first wireless communication means includes
2. The driving support device according to claim 1, wherein when the vehicle approach determining unit determines that the vehicle is approaching, the approach information of the vehicle is transmitted by the first wireless communication method. Communication tag. The transmission cycle adjusting means includes
The transmission cycle of the second wireless communication method is adjusted when a time longer than a preset length has elapsed since the detection of the other communication tag. Item 3. A communication tag for driving support according to Item 2. The transmission cycle adjusting means includes
4. The transmission period of the second wireless communication method is adjusted based on the number of the other communication tags detected by the communication tag detection unit. 5. The communication tag for driving support described in 1. The transmission cycle adjusting means includes
The transmission period of the second wireless communication method is adjusted based on the remaining battery level information of the communication tag and the remaining battery level information of the other communication tag detected by the communication tag detection unit. The communication tag for driving assistance according to any one of claims 1 to 3. Based on the position information of the communication tag acquired by the position information acquisition means, further comprising a movement amount detection means for detecting the movement amount of the communication tag per time,
The second wireless communication means includes
The driving assistance according to any one of claims 1 to 5, wherein the second wireless communication method is stopped when the movement amount is out of a preset numerical range. Communication tag. The second wireless communication means includes
The driving support according to claim 6, wherein after the second wireless communication method is stopped, the second wireless communication method is started when the movement amount is within the numerical range. Communication tag for. The second wireless communication means includes
6. The second wireless communication method is stopped when the in-vehicle wireless communication is received by the first wireless communication means for a preset time. The communication tag for driving assistance described. The second wireless communication means includes
The second wireless communication system is started when the in-vehicle wireless communication is not received for a preset time after stopping the second wireless communication system. 8. A communication tag for driving support according to 8.   10. The reception cycle adjustment unit according to claim 1, further comprising: a reception cycle adjustment unit configured to adjust a reception cycle of the second wireless communication scheme based on a detection result of the other communication tag. Communication tag for driving assistance. When the other communication tag is detected,
The transmission cycle adjusting unit changes the transmission cycle from the first transmission cycle to a second transmission cycle having a cycle longer than the first transmission cycle, and the reception cycle adjusting unit sets the reception cycle to the first transmission cycle. Change from one reception cycle to a second transmission cycle that is longer than the first reception cycle,
When the other communication tag is not detected after the transmission period is changed to the second transmission period and the reception period is changed to the second reception period,
While the transmission cycle adjusting means maintains the transmission cycle at the second transmission cycle, the reception cycle adjusting means changes the reception cycle from the second reception cycle to the first reception cycle, and this state Then, the communication tag detection means tries to detect the other communication tag via the first wireless communication means,
As a result of the trial, when the other communication tag is detected again, the reception cycle adjustment means changes the reception cycle from the first reception cycle to the second reception cycle,
On the other hand, when the other communication tag is not detected as a result of the trial, the transmission cycle adjusting means changes the transmission cycle from the second transmission cycle to the first transmission cycle. Item 11. The communication tag for driving support according to Item 10. Further comprising information exchange means for exchanging information with the other communication tag detected by the communication tag detection means and the first wireless communication means,
The said 2nd radio | wireless communication means transmits the said information exchanged by the said information exchange means by a said 2nd radio | wireless communication system, The Claim 1 characterized by the above-mentioned. Communication tag for driving support. A driving support system for notifying a vehicle of the presence of a communication tag,
Including the communication tag and an in-vehicle device mounted on the vehicle,
The communication tag is
First wireless communication means for communicating by a first wireless communication method;
Position information acquisition means for acquiring position information of the communication tag;
Second wireless communication means for transmitting the position information of the communication tag acquired by the position information acquisition means by a second wireless communication method having a communication distance longer than that of the first wireless communication method;
A communication tag detecting means for detecting another communication tag having the same function as the communication tag via the first wireless communication means;
A transmission period adjusting means for adjusting a transmission period of the second wireless communication system based on a detection result of the other communication tag,
The in-vehicle device is
Receiving means for receiving position information of the communication tag transmitted from the communication tag by the second wireless communication method;
And a display means for displaying position information of the communication tag received by the receiving means in at least one of sound and image.

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