JP6022926B2 - Terminal apparatus and radio communication system - Google Patents

Description

  The present invention relates to a terminal device that wirelessly transmits data corresponding to a request signal when receiving a request signal transmitted from a roadside device arranged on the roadside, and a wireless communication system.

  As the wireless communication system, there is known a terminal device configured to transmit data only when a request signal is received from a roadside device (see, for example, Patent Document 1).

Japanese Patent Application No. 2007-42009

  However, in a wireless communication system, data transmission from a terminal device is limited to when a request signal is received. Therefore, when data transmission is performed from a terminal device, depending on the positional relationship with the receiving device and radio wave conditions, There is a problem in that the data on the terminal device cannot be received normally. In order to solve such a problem, the terminal device may continuously perform data transmission, but this configuration cannot be adopted when there is a limit on the power consumption of the terminal device. .

  Therefore, in view of such a problem, when a request signal transmitted from a roadside device arranged on the roadside is received, in a configuration including a terminal device that wirelessly transmits data corresponding to the request signal, An object of the present invention is to improve the reliability with which data can be received and to save power consumption in the terminal device.

  In the terminal device of the present invention configured to achieve such an object, the request signal receiving means receives the request signal, and the priority acquisition means is the priority included in the request signal or the environment where the terminal device is placed. At least one of the priorities generated in response is acquired. Then, the transmission parameter setting means sets a transmission parameter indicating a parameter relating to radio wave transmission according to the acquired priority, and the location information transmitting means transmits location information including data indicating its own presence according to the transmission parameter.

  According to such a terminal device, since the transmission parameter is set according to the priority, only when the priority is high, the setting at the time of transmitting the location information is changed, such as increasing the transmission frequency and the number of times of transmission. be able to. Therefore, the location information can be reliably transmitted to the device that receives the location information, and the power consumption in the terminal device can be saved.

  In order to achieve the above object, the computer may be a program for realizing each unit constituting the terminal device, or may be configured as a system including the terminal device. Further, the descriptions in the claims can be arbitrarily combined as much as possible. At this time, a part of the configuration may be excluded within a range in which the object of the invention can be achieved.

1 is a block diagram showing a schematic configuration of a notification system 1 to which the present invention is applied. It is a bird's-eye view which shows the outline | summary of the alerting | reporting system 1 of 1st Embodiment. In 1st Embodiment, it is a flowchart which shows the terminal process which the terminal control part 21 of the terminal device 20 performs. It is explanatory drawing (the 1) which shows the structure of the data exchanged in the alerting | reporting system. It is a bird's-eye view which shows the outline | summary of the alerting | reporting system of 2nd Embodiment. It is a flowchart which shows the terminal process of 2nd Embodiment. It is explanatory drawing (the 2) which shows the structure of the data exchanged in the alerting | reporting system. In 2nd Embodiment, it is a flowchart which shows the speed estimation process which the terminal control part 21 of the terminal device 20 performs.

Embodiments according to the present invention will be described below with reference to the drawings.
[Configuration of this embodiment]
The notification system 1 to which the present invention is applied is a system for reporting the presence of a moving object to the surroundings. Specifically, as shown in FIG. 1, the roadside device 10, the terminal device 20, and the notification device 40 are provided. In the present embodiment, a plurality of roadside devices 10 are provided. Since these roadside devices 10 have the same configuration, FIG. 1 shows one roadside device 10.

  As shown in FIG. 1, the roadside device 10 includes a roadside control unit 11, an HF band transmission unit 12, and a position detection unit 13. The roadside control unit 11 is configured as a known computer including a CPU, a ROM, a RAM, and the like, and performs processing according to a predetermined program.

  The HF band transmission unit 12 is configured as a communication module capable of transmitting HF band radio waves used for extremely short distance communication. The HF band transmission unit 12 transmits a request signal for requesting data transmission in response to a command from the roadside control unit 11.

  The position detection unit 13 is configured as, for example, a well-known GPS receiver, and sends a position detection result to the roadside control unit 11. The position detection unit 13 may send any information to the roadside control unit 11 as long as it is position specifying information that can specify the position of the roadside device 10. For example, when the receiving device (the terminal device 20 or the device that has received the signal transmitted from the terminal device 20) includes a map that associates the identification information and the position of the road device 10, the road device 10 The identification information may be sent.

  Here, as shown in FIG. 2, the plurality of roadside devices 10 are arranged around the road near the intersection. More specifically, the roadside device 10 is arranged on a structure arranged on a road such as a guardrail or a traffic signal, and is required within a preset target area (for example, within a radius of about 3 m from itself). A signal and position specifying information are periodically transmitted.

  These roadside devices 10 are respectively arranged at different distances from the intersection, and the terminal device 20 is set to sequentially receive request signals from a plurality of roadside devices 10 as the terminal device 20 moves. . And the terminal device 20 is comprised so that the distance to an intersection can be recognized by which roadside apparatus 10 received the signal.

  As shown in FIG. 2, the terminal device 20 is possessed or mounted on a moving object that is a traffic weak when viewed from a vehicle such as a pedestrian or bicycle. As illustrated in FIG. 1, the terminal device 20 includes a terminal control unit 21, an HF band receiving unit 22, and a UHF band transmitting unit 23.

The HF band receiving unit 22 is configured to be able to receive HF band radio waves, and in particular has a function of receiving HF band radio waves transmitted from the roadside device 10.
The UHF band transmission unit 23 is configured as a communication module capable of transmitting UHF band radio waves having a communication range within the line-of-sight range. The UHF band transmission unit 23 transmits data in response to a command from the terminal control unit 21.

  Similar to the roadside control unit 11, the terminal control unit 21 is configured as a known computer including a CPU, a ROM, a RAM, and the like, and performs processing according to a predetermined program. In particular, when the terminal control unit 21 receives the request signal and the position specifying information via the HF band receiving unit 22, the terminal control unit 21 transmits the identification information (ID) of the terminal device 20 and the received position specifying information via the UHF band transmitting unit 23. To send without specifying the communication partner.

  As illustrated in FIG. 2, the notification device 40 is capable of receiving radio waves from the terminal device 20 and is mounted on a moving body such as a vehicle that is different from the moving body related to the terminal device 20. And the notification apparatus 40 is provided with the notification control part 41, the UHF zone | band receiving part 42, and the notification part 43, as shown in FIG.

  The UHF band receiving unit 42 is configured to be able to receive UHF band radio waves, and in particular has a function of receiving UHF band radio waves transmitted from the communication device 20. The notification unit 43 includes a display, a speaker, and the like, and performs a notification such as an alarm using a display, a speaker, or the like in response to a command from the notification control unit 41.

  The notification control unit 41 is configured as a well-known computer including a CPU, a ROM, a RAM, and the like, similarly to the roadside control unit 11 and the like, and performs processing according to a predetermined program. In particular, when a UHF band radio wave transmitted from the roadside device 30 is received, an alarm is issued via the notification unit 43.

[Process of this embodiment]
In such a notification system 1, the terminal device 20 performs the terminal processing shown in FIG. The terminal process is, for example, a process that is started when the terminal device 20 is turned on and then repeatedly executed.

  As for the details of the terminal processing, as shown in FIG. 3, first, it is determined whether or not the HF signal (request signal) transmitted from the roadside device 10 has been received via the HF band receiving unit 22 (S110). If the HF signal is not received (S110: NO), the process of S110 is repeated.

  If the HF signal is received (S110: YES), the position information included in the HF signal is written in the RAM (storage unit) of the terminal control unit 21 (S120). Here, as shown in FIG. 4A, the HF signal includes transmission time, position information, infrastructure ID, and priority information.

  The infrastructure ID indicates a unique ID (identifier) that identifies the roadside device 10. The priority information is information indicating a part of transmission parameters, and indicates the degree of certainty required when information from the terminal device 20 is transmitted to the notification device 40. This priority information is set according to the situation of the intersection, such as the visibility of the intersection, the gradient, and the like, and is set to be higher as the distance from the intersection of the roadside device 10 becomes shorter.

  Subsequently, transmission parameters representing parameters relating to various settings when radio waves are transmitted from the terminal device 20 are set (S130). Here, the transmission parameter is set according to the acquired priority. Specifically, as shown in FIG. 4B, for example, in the ROM of the terminal device 20, for example, the packet transmission interval Td, the radio wave intensity TxP, the number of transmissions Nmax, the speed threshold value Vth, and the vibration frequency threshold value. It has a table in which αn_th and a vibration magnitude threshold value αm_th are associated with each other.

  In the example shown in FIG. 4B, the priority is set in three stages of 1 to 3, with priority 3 being set to the highest priority and priority 1 being set to the lowest priority. As the priority increases, the location information is transmitted more frequently, the location information transmission cycle is shorter, and the radio wave intensity at the time of transmitting the location information is increased.

  In the transmission parameter table, a large number of transmission parameters can be set, and any transmission parameter can be set. That is, it is not essential to use all transmission parameters. In this processing, the packet transmission interval Td, the number of transmissions Nmax, the speed threshold value Vth, and the vibration frequency threshold value αn_th are set as transmission parameters, and the radio wave intensity TxP and the vibration magnitude threshold value αm_th are not used.

  Subsequently, the speed of the moving object is compared with a reference speed (speed threshold Vth) set as a transmission parameter (S310). Here, the speed of the moving object may be estimated from, for example, a position detection history by a well-known GPS receiver, may be estimated from a well-known speed sensor, or other configurations such as a configuration shown in a modified example to be described later. It is good also as a structure.

  If the speed of the moving object is equal to or lower than the reference speed (S310: NO), the process returns to S110. If the speed of the moving object is larger than the reference speed (S310: YES), the vibration frequency per unit time of the moving object is compared with the reference frequency (frequency threshold value αn_th) (S320). Here, the vibration frequency of the moving object may be obtained from a known acceleration sensor or the like.

  If the frequency of the moving object is equal to or lower than the reference frequency (S320: NO), the process returns to S110. If the frequency of the moving object is greater than the reference frequency (S320: YES), the set transmission parameter is read, and the transmission timing and output are set according to the transmission parameter (S140).

  Then, data is transmitted according to this setting (S150). Here, the data transmitted from the terminal device 20 includes information of transmission time, position information, infrastructure ID, priority, and tag ID, as shown in FIG. 4C, for example.

  In this process, it can be set as the structure which transmits the data which added tag ID with respect to the data received from the roadside apparatus 10, and in this way, the process which produces | generates data in the terminal device 20 can be simplified. it can. When a packet is transmitted in the process of S150, the timer is started and the timer time T is started.

  Subsequently, the number N of packet transmissions from the terminal device 20 is compared with the number Nmax of transmissions set as a transmission parameter (S160). If the number of transmissions N is less than the number of transmissions Nmax (S160: YES), it is determined whether or not the HF signal (request signal) transmitted from the roadside device 10 has been received via the HF band receiver 22 (S170). ).

  If the HF signal has not been received (S170: NO), the number of transmissions N is incremented, the system waits for the transmission interval Td set as the transmission parameter (S190), and the process returns to S140. If the HF signal is received (S170: YES), the timer time T and the number of transmissions N are reset, and the process returns to S120.

If the number of transmissions N is greater than or equal to the number of transmissions Nmax in the process of S160 (S160: NO), the terminal process is terminated.
[Effects of this embodiment]
In the notification system 1 described in detail above, the roadside device 10 (roadside control unit 11) transmits a request signal within a preset area via the HF band transmission unit 12, and the terminal device 20 (terminal control). The unit 21) receives the request signal and obtains at least one of the priority included in the request signal or the priority generated according to the environment where the terminal device 20 is placed. And the terminal device 20 sets the transmission parameter showing the parameter regarding radio wave transmission according to the acquired priority, and transmits the location information including the data indicating its own presence according to the transmission parameter.

  According to such a notification system 1, since the transmission parameter is set according to the priority, only when the priority is high, the setting for transmitting the location information is changed, such as increasing the transmission frequency and the number of transmissions. can do. Therefore, the location information can be reliably transmitted to the device that receives the location information, and the power consumption in the terminal device 20 can be saved.

  In the notification system 1, the terminal device 20 compares the moving speed of the terminal device 20 with a preset speed reference value, and if the moving speed of the terminal device 20 is equal to or higher than the speed reference value, the location information Send.

According to such a notification system 1, the location information can be transmitted when the moving speed of the terminal device 20 is high and the priority for transmitting the location information is high.
Further, in the notification system 1, the terminal device 20 compares the magnitude or vibration cycle of the vibration applied to the terminal device 20 with a preset vibration reference value, and the magnitude or vibration cycle of the vibration applied to the terminal device 20. If is greater than or equal to the vibration reference value, the location information is transmitted.

  According to such a notification system 1, when the vibration of the terminal device 20 is intense and it can be estimated that the terminal device 20 is moving, the location information can be transmitted with high priority for transmitting the location information. it can.

  Furthermore, in the notification system 1, the terminal device 20 sets the number of times location information is transmitted more frequently, shortens the location information transmission cycle, or transmits the location information as the priority increases. At least one of setting of increasing the strength is set.

According to such a notification system 1, it is possible to increase the accuracy with which a device that receives location information can receive location information as priority increases.
Further, in the notification system 1, the roadside device 10 (roadside control unit 11) transmits a request signal including information related to the priority.

According to such a notification system 1, the transmission parameter in the terminal device 20 can be set by transmitting the priority by the roadside device 10.
In the notification system 1, the roadside includes a plurality of roadside devices 10, and the terminal device 20 is set to sequentially receive request signals from the plurality of roadside devices 10 as the terminal device 20 moves. At the same time, the priority included in the request signal is set to be higher as the distance from the intersection of the roadside device 10 becomes shorter.

  According to such a notification system 1, the priority can be set higher as the terminal device 20 approaches the intersection. For example, when a speed threshold value is set as a transmission parameter from FIG. 4B, a terminal with a higher moving speed transmits a packet from a position farther from the intersection, while a terminal with a lower moving speed transmits a packet at a position far from the intersection. Is not transmitted, so that power consumption of the terminal can be saved.

[First Modification]
Embodiments of the present invention are not limited to the above-described embodiments, and can take various forms as long as they belong to the technical scope of the present invention.

  For example, in the said embodiment, although it was set as the structure provided with the several roadside apparatus 10 in a certain intersection, as shown in FIG. 5, you may provide only one roadside apparatus 10. As shown in FIG. If it does in this way, since the number of the roadside apparatuses 10 can be suppressed, a system can be simplified.

[Second Modification]
Further, in the above embodiment, in the terminal processing, when the moving speed of the terminal device 20 is equal to or higher than the speed reference value, and when the magnitude or vibration period of the vibration applied to the terminal device 20 is equal to or higher than the vibration reference value, Although the data is transmitted from the terminal device 20, as shown in FIG. 6, these processes (S310, S320) may be omitted. Any one of these processes may be omitted.

[Third Modification]
Moreover, in the said embodiment, although the roadside apparatus 10 transmitted the request signal containing a priority, the parameter which the terminal device 20 should set as transmission parameters, such as transmission interval Td, speed threshold Vth, or transmission frequency, is transmitted. Also good. In this case, the terminal device 20 may not include the transmission parameter, or may preferentially adopt one of the plurality of transmission parameters.

  Thus, when transmitting the transmission parameter from the roadside device 10, as shown in FIG. 7, the request signal transmitted from the roadside device 10 includes information on the transmission time, location information, infrastructure ID, and transmission parameter. It only has to be included.

  According to such a notification system 1, since the terminal device 20 acquires parameters related to radio wave transmission from the roadside device 10, it is possible to easily set transmission parameters. And if the acquired parameter itself is set as a transmission parameter, the process at the time of setting a transmission parameter can be simplified.

[Fourth Modification]
In the above embodiment, the configuration in which the terminal device 20 detects the moving speed of the moving object is not particularly specified. However, the terminal device 20 moves according to the number of packets received from the roadside device 10 and information on the contents. You may implement the process which estimates the moving speed and moving direction of an object. Moreover, you may set whether to alert | report according to a moving speed etc. (for example, whether to transmit data from the terminal device 20).

  As a process for estimating the moving speed of such a moving object or setting whether or not to perform notification, for example, a speed estimation process shown in FIG. 8 may be executed. In addition, about the process which estimates the speed of a moving object, apparatuses which can receive the electromagnetic wave from the terminal device 20, such as the notification apparatus 40, may implement.

  In the notification system 1, the speed estimation process is performed according to the number of times (the number of packets) that the roadside control unit 11 periodically transmits a request signal via the HF band transmission unit 12 and the terminal device 20 receives the request signal. This is a process for estimating the moving speed of the moving object.

  In addition, the speed estimation process is a process that is started at each cycle in which a request signal is transmitted from the roadside device 10 as illustrated in FIG. 8. In the speed estimation process, first, it is determined whether or not a request signal has been received (S410).

  If a response is received (S410: YES), the ID of the roadside apparatus 10 is specified (S420), the counter related to this ID is incremented (S430), and the speed estimation process is terminated. If no response has been received (S410: NO), it is determined whether or not a standby time for receiving the response has elapsed (S440).

  If the standby time has not elapsed (S440: NO), the process returns to S410. If the standby time has elapsed (S440: YES), the moving speed of the moving object is estimated according to the counter value (the number of times data for the request signal has been received) (S450). In this process, for example, the moving speed is estimated from the size of a range in which a request signal from the roadside device 10 is transmitted (for example, a formation area having a radius of about 3 m) and the number of times data is received.

  More specifically, for example, the moving speed V can be calculated by the following mathematical formula.

また、報知システム１では、複数の路側装置１０を備えているので、端末装置２０が路側装置１０から送信される位置情報を順次取得し、その変化を検出することで、端末装置２０は移動物の移動方向を特定することができる。

In addition, since the notification system 1 includes a plurality of roadside devices 10, the terminal device 20 sequentially acquires position information transmitted from the roadside device 10 and detects the change thereof, whereby the terminal device 20 is moved. Can be specified.

  And it is determined whether the priority which performs alerting | reporting is high according to a moving speed, a moving direction, or the position where the terminal device 20 was detected (S460). When the priority to perform notification is high and notification is necessary, a signal instructing notification by the notification unit 43 or the like is transmitted (S470). Then, the counter is cleared (S480), and the speed estimation process is terminated. Even if the counter is reset, the notification may be continued for a certain time.

  According to such a notification system 1, the moving speed of the moving object can be estimated according to the number of times data is received, and therefore it is not necessary to acquire speed information from the outside of the terminal device 20 (speed sensor or the like). . Therefore, communication can be simplified and the configuration of the terminal device 20 can be simplified.

[Fifth Modification]
In the above-described embodiment, the terminal device 20 acquires information on the priority from the roadside device 10, but the terminal device 20 may set the priority. For example, the priority may be set according to the magnitude or direction of movement of the terminal device 20 or the magnitude of vibration. In this case, the priority may be set higher as the moving vector moves in the direction of the intersection, the moving speed increases, or the magnitude of vibration increases.

According to such a wireless communication system, the terminal device 20 itself can set the priority according to the environment.
Note that when the terminal device 20 generates the priority, it may be generated based only on the information obtained by the terminal device 20 itself, or may be generated taking into account the information acquired from the roadside device 10. Good.

[Relationship Between Configuration of the Present Invention and Embodiment]
In the said embodiment, the roadside control part 11 is corresponded to the request transmission means said by this invention. Further, the processing of S120 and S130 in the above embodiment corresponds to the priority acquisition means referred to in the present invention, and the processing of S130 corresponds to the transmission parameter setting means referred to in the present invention.

  Further, the process of S150 corresponds to the location information transmission means referred to in the present invention, and the process of S310 corresponds to the speed comparison means referred to in the present invention. Further, the process of S320 corresponds to the vibration comparing means referred to in the present invention, and the processes of S410 to S450 correspond to the moving speed detecting means referred to in the present invention.

DESCRIPTION OF SYMBOLS 1 ... Notification system, 10 ... Roadside device, 11 ... Roadside control unit, 12 ... HF band transmission unit, 13 ... Position detection unit, 20 ... Terminal device, 21 ... Terminal control unit, 22 ... HF band reception unit, 23 ... UHF Belt transmission unit, 40 ... notification device, 41 ... notification control unit, 41 ... road road control unit, 42 ... UHF band reception unit, 43 ... notification unit.

Claims (9)

When receiving a request signal transmitted from a roadside device (10) arranged on the roadside, the terminal device (20) wirelessly transmits data corresponding to the request signal,
Request signal receiving means (S110) for receiving the request signal;
Priority acquisition means (S120, S130) for acquiring at least one of the priority included in the request signal or the priority generated according to the environment in which the terminal device is placed;
Transmission parameter setting means (S130) for setting a transmission parameter representing a parameter relating to radio wave transmission according to the acquired priority;
Comparison means (S310, S320) for comparing the transmission parameter with a threshold value for a preset transmission parameter;
Location information transmission means for receiving location information including data indicating the presence of the request signal according to the transmission parameter when the request signal is received and a comparison result between the transmission parameter and the threshold satisfies a preset condition (S150),
A terminal device comprising: The terminal device according to claim 1,
The comparison means is a speed comparison means (S310) for comparing the moving speed of the terminal device with a preset speed reference value,
With
The location information transmitting means transmits the location information when the request signal is received and the moving speed of the terminal device is equal to or higher than the speed reference value. In the terminal device according to claim 1 or 2,
The comparison means is a vibration comparison means (S320) for comparing the magnitude or vibration period of vibration applied to the terminal device with a preset vibration reference value.
With
The location information transmitting means receives the request signal and transmits the location information when the magnitude or vibration period of vibration applied to the terminal device is equal to or greater than a vibration reference value. In the terminal device according to any one of claims 1 to 3,
As the priority increases, the transmission parameter setting means sets the number of times location information is transmitted, shortens the location information transmission cycle, or increases the radio wave intensity when transmitting location information. Or at least one of the settings is performed. In the terminal device according to any one of claims 1 to 4,
The priority acquisition means acquires information including a parameter relating to radio wave transmission as a priority included in the request signal,
The transmission parameter setting means sets the transmission parameter in consideration of the acquired parameter. A wireless communication system (1) comprising a roadside device arranged on the roadside and a terminal device movable on the road,
The roadside device includes request transmission means (11) for transmitting a request signal within a preset area,
With
The wireless communication system, wherein the terminal device is configured as the terminal device according to any one of claims 1 to 5. The wireless communication system according to claim 6.
The wireless communication system, wherein the request transmitting means transmits a request signal including information on the priority. The wireless communication system according to claim 7,
The roadside includes a plurality of roadside devices provided with the request transmission means,
The request signal receiving means is set to sequentially receive request signals from a plurality of roadside devices as the terminal device moves.
The wireless communication system, wherein the priority included in the request signal is set to be higher as the distance from the intersection of the roadside device is closer. In the radio | wireless communications system of any one of Claims 6-8,
The terminal device
A moving speed detecting means (S410 to S450) for calculating the moving speed based on the number of packets received per unit time from each roadside device;
A wireless communication system comprising:

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