JP6512371B2 - Fixed wireless communication device and mobile wireless communication device - Google Patents

Description

  The present invention relates to a wireless communication apparatus used in a system for selecting a device to be a reader from among a plurality of devices by wireless communication.

  When a plurality of devices belonging to a group operate in cooperation, selecting a leader from the devices in the group enables a smooth cooperation operation. For example, when one of a plurality of vehicles traveling automatically tries to change the relative position in the group, a vehicle serving as a leader is selected, and a collision or the like is performed by changing the position under the management of the leader. Can reduce the risk of

  As a method of autonomously selecting a leader, a method in which devices in a group vote as a response to a request for voting (transmission request) from a device of a leader candidate, and a device with support from a majority of devices is elected as a leader There is. Here, when the devices in the group are separated from one another, it is effective to use wireless communication for voting. For example, Patent Document 1 discloses a voting system in which test transmission is performed beforehand and different transmission timings are set for the respective terminal devices so that radio signals transmitted by the respective terminal devices do not collide, and then voting is performed. There is.

JP, 2011-19705, A

  In the case of performing reader selection by applying the above-described conventional voting method using wireless communication, it is necessary to perform test transmission in advance and set the transmission timing of each terminal device before the reader selection. However, in the case where the configuration of the group changes dynamically as in the case of the group configured by vehicles described above, it is desirable to be able to implement leader election with the test transmission overhead as small as possible. There is a CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) method as a known technique for collision avoidance in wireless communication, but the mere application of the CSMA / CA method results in concealment between devices which have received voting requests from candidate readers. Terminal problems can cause responses to collide.

  The present invention has been made to solve the above problems, and determines the transmission timing of responses to transmission requests with less overhead, thereby reducing the collision establishment of responses transmitted from the respective devices. An object of the present invention is to obtain a leader election system capable of improving the success probability of leader election.

  A reader is selected from the plurality of mobile bodies by wireless communication of a CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) system including a fixed radio communication device and a plurality of mobile radio communication devices respectively mounted on a plurality of mobile bodies. Message receiving section for receiving a periodic message periodically transmitted from the mobile wireless communication apparatus, a reception timing recording section for recording the reception timing of the periodic message, and reception of the periodic message Based on the timing, a transmission timing determination unit that allocates transmission timing to each mobile radio communication device, and movement as a leader candidate from among mobiles equipped with the mobile radio communication device that is a transmission source of the received periodic message A leader candidate determination unit that determines the body, the start of And a message transmitting unit for generating a voting request message for notifying the mobile radio communication apparatus of the mobile unit and the allocated transmission timing.

  A reader is selected from the plurality of mobile bodies by wireless communication of a CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) system including a fixed radio communication device and a plurality of mobile radio communication devices respectively mounted on a plurality of mobile bodies. A mobile radio communication device in a mobile communication system, the message reception unit receiving messages from the fixed radio communication device and another mobile radio communication device, the start of reader selection, and the transmission timing assigned to the mobile body of the reader candidate And a reader operation determination unit that determines whether or not the own device operates as a reader candidate based on the vote request message when a vote request message indicating the message is received from the fixed wireless communication device; When creating and transmitting a message and when the device itself operates as a reader candidate, another mobile radio communication device When the reader proposal message notifying that the device is a reader candidate is created and the device itself does not operate as a reader candidate, when receiving a reader proposal message from another mobile radio communication device, at most one mobile radio communication An acceptance response message for notifying the device that the mobile wireless communication device is accepted as a reader is prepared, and a message transmitting unit for transmitting the prepared message at the transmission timing indicated in the voting request message is provided. It is a thing.

  According to the fixed wireless communication device and the mobile wireless communication device of the present invention, the fixed wireless communication device determines the transmission timing of each mobile wireless communication device based on the reception timing of the periodic message transmitted from the mobile wireless communication device Each mobile radio communication device is notified of the transmission timing determined as the start of selection and each mobile radio communication device is notified of the start of leader selection, and transmits a message for reader selection at a designated transmission timing. Since it is possible to improve the success rate of communication by reducing the probability of message loss due to a hidden terminal problem with a small overhead when performing wireless communication of the CSMA / CA method, the leader is elected with high probability. It is possible to

It is a block diagram which shows one structural example of the reader | leader election system provided with the fixed wireless communication apparatus which concerns on Embodiment 1 of this invention, and a mobile wireless communication apparatus. FIG. 2 is a block diagram showing an example of a functional configuration of the fixed wireless communication device of the first embodiment. FIG. 1 is a block diagram showing an example of a hardware configuration of a fixed wireless communication device according to a first embodiment. FIG. 2 is a block diagram showing an example of a functional configuration of a mobile radio communication apparatus of Embodiment 1. FIG. 2 is a block diagram showing an example of a hardware configuration of a mobile radio communication apparatus of Embodiment 1. 5 is a flowchart showing an example of a process flow of the fixed wireless communication device of the first embodiment. 5 is a flowchart showing an example of the processing flow of the mobile radio communication apparatus of the first embodiment. 5 is a timing diagram for describing a specific example of transmission timing determination performed by the fixed wireless communication device of the first embodiment. 5 is a timing diagram for describing a specific example of transmission timing determination performed by the fixed wireless communication device of the first embodiment. FIG. 7 is a schematic view showing an operation example of the merging support system to which the leader and election system according to Embodiment 1 is applied. 15 is a timing diagram illustrating an example of transmission timing determination performed by the fixed wireless communication device of the second embodiment. FIG. 16 is a timing diagram illustrating an example of transmission timing determination performed by the fixed wireless communication device of the third embodiment.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings. In the drawings referred to in the following, the same or corresponding parts are denoted by the same reference numerals.

Embodiment 1
FIG. 1 is a block diagram showing an example of the configuration of a leader election system according to Embodiment 1 of the present invention. The reader selection system shown in FIG. 1 includes a fixed wireless communication device 100 and six mobile wireless communication devices 200 _{1 to} 200 ₆ which are communication devices mounted on a mobile unit. The mobile radio communication apparatuses 200 _{1 to} 200 ₆ are apparatuses having the same configuration, and are described as the mobile radio communication apparatus 200 when it is not necessary to distinguish the individual apparatuses in the following description. Further, although the number of mobile radio communication devices 200 shown in FIG. 1 is six, the present invention does not limit the number of mobile radio communication devices 200, and may be more or less than six.

  The leader selection system shown in FIG. 1 is a system in which mobiles corresponding to each of six mobile radio communication apparatuses 200 form a group and select one leader from mobiles in the group. In addition, since the mobile radio communication apparatus 200 mounted on the mobile object and the mobile object corresponds one to one, selecting a specific mobile object as a reader selects the corresponding mobile radio communication apparatus 200 as a reader. That is equivalent.

  FIG. 2 is a block diagram showing an example of a functional configuration of fixed wireless communication apparatus 100 according to this embodiment. The fixed wireless communication device 100 includes a wireless transmission / reception unit 101, a message reception unit 102, a message recording unit 103, a reception timing recording unit 104, a reader candidate determination unit 105, a transmission timing determination unit 106, a message transmission unit 107, and an antenna 109. There is.

  The wireless transmission and reception unit 101 transmits and receives a wireless signal including a periodic message exchanged with the surrounding mobile wireless communication device 200 via the antenna 109. Here, it is assumed that the wireless transmission / reception unit 101 performs wireless communication of the CSMA / CA system. As a known communication technology of the CSMA / CA system, there is a communication technology of the IEEE 802.11 standard. The message reception unit 102 performs reception processing of a periodic message included in the wireless signal received by the wireless transmission / reception unit 101. The message recording unit 103 records information contained in the received periodic message. Further, the reception timing recording unit 104 records the timing (reception timing) at which each periodic message is received.

  Based on the received periodic message, the reader candidate determination unit 105 determines the mobile radio communication apparatus 200 mounted on the mobile unit to be the reader candidate. As described above, selecting a reader from a mobile is equivalent to selecting a reader from the mobile radio communication apparatus 200. Therefore, in the following description, a mobile radio communication apparatus mounted on a mobile that is a candidate for a reader 200 may be referred to as a leader candidate. The same applies to devices that are not leader candidates. The transmission timing determination unit 106 determines the transmission timing at which each mobile radio communication apparatus 200 transmits a message. The message transmission unit 107 notifies transmission timing to each of the candidate reader device and the non-leader candidate device according to the notification of occurrence of an event (trigger event) serving as a trigger for reader selection input from the event detection unit 110. Create a message and output the created message. The message created by the message transmission unit 107 is converted to a wireless signal via the wireless transmission / reception unit 101 and the antenna 108 and transmitted.

  FIG. 3 is a block diagram showing an example of the hardware configuration of fixed wireless communication apparatus 100. As shown in FIG. The fixed wireless communication device 100 illustrated in FIG. 3 includes a processor 120, a storage 121, a memory 122, a wireless transceiver (transceiver) 123, and an antenna 108. Among the functional blocks shown in FIG. 2, the message reception unit 102, the message recording unit 103, the reception timing recording unit 104, the reader candidate determination unit 105, the transmission timing determination unit 106, and the message transmission unit 107 include software, firmware, Or realized by a combination of software and firmware. Software and firmware are described as a program and stored in the memory 122. Each function is realized by the processor 220 reading and executing the program stored in the memory 122. In addition, when the message recording unit 103 and the reception timing recording unit 104 record information while the program is being executed, the data may be held using the memory 122, or the data may be held using the storage 121. You may Further, the wireless transmission / reception unit 101 can be realized by the transceiver 123 compatible with the CSMA / CA method.

  The event detector 110 can use various sensors according to the actual application of the present invention. For example, if the fixed wireless communication device 100 is a device installed on the roadside that communicates with the mobile wireless communication device 200 mounted on a vehicle, and a trigger event is detected according to the condition of the vehicle on the road, As shown in FIG. 4, it is possible to use the image sensor 224 as the event detection unit 110, and it is also conceivable to use an ultrasonic sensor.

  FIG. 4 is a block diagram showing an example of a functional configuration of mobile radio communication apparatus 200 according to Embodiment 1 of the present invention. The mobile radio communication device 200 includes a radio transmission / reception unit 201, a message reception unit 202, a mode switching unit 203, a reader operation determination unit 204, a message transmission unit 205, and an antenna 209.

  The wireless transmission and reception unit 201 transmits and receives a wireless signal including a message exchanged between the fixed wireless communication device 100 and another mobile wireless communication device 200 in the vicinity via the antenna 209. Here, it is assumed that the wireless transmission / reception unit 201 performs wireless communication by the CSMA / CA method as in the fixed wireless communication device 100. The message receiving unit 202 receives messages from the fixed wireless communication device 100 and the other mobile wireless communication device 200 and performs analysis processing. The mode switching unit 203 switches the mode of the own apparatus based on the analysis result of the message receiving unit 202.

  The reader operation determination unit 204 has an interface with the mobile control unit 210, and determines whether or not the own device operates as a communication device of a mobile candidate as a reader candidate. The message transmission unit 205 creates a reader proposal message which is a voting request message for notifying the mobile communication apparatus 200 of the start of voting when the mobile unit mounting the own apparatus is a leader candidate, and when it is not a leader candidate. It generates an acceptance response message, which is a voting message, and transmits the created message at a designated transmission timing.

  FIG. 5 is a block diagram showing an example of the hardware configuration of the mobile radio communication device 200. As shown in FIG. The mobile radio communication apparatus 200 shown in FIG. 5 includes a processor 220, a storage 221, a memory 222, a transceiver 223, and an antenna 208. Among the functional blocks shown in FIG. 4, the message reception unit 202, the mode switching unit 203, the reader operation determination unit 204, and the message transmission unit 205 are realized by software, firmware, or a combination of software and firmware. Software and firmware are described as a program and stored in the memory 222. Each function is realized by the processor 220 reading and executing the program stored in the memory 222. Retention of data necessary for execution of the program of each function is performed using the memory 222 or storage 221. Also, the wireless transmission / reception unit 201 can be realized by the transceiver 223.

  The mobile control unit 210 is a block that controls a mobile mounted with the mobile wireless communication device 200. For example, when the mobile is an automatic traveling vehicle, the mobile control unit 210 controls the traveling of the vehicle as shown in FIG. Corresponding vehicle controller 224. The vehicle controller 224 can be realized by a processor, processor peripheral circuits, and a program executed on the processor. The connection between the vehicle controller 224 and the mobile radio communication device 200 may be made by applying an existing inter-device interface. If the vehicle controller 224 is realized using a processor, it may be considered to share the processor 220 with the mobile radio communication device 200. The mobile control unit 210 may not be configured using a processor, but may be realized by hardware such as a logic circuit.

  Next, the operation of the reader selection system according to the first embodiment will be described. First, the operation of fixed wireless communication apparatus 100 will be described. FIG. 6 is a flowchart showing an example of the processing flow of the fixed wireless communication device 100 of this embodiment. The flowchart shown in FIG. 6 is an example, and if necessary, the order of processing may be changed and parallelization may be performed. Also, the wireless transmitting / receiving unit 101 and the antenna 109 provide a wireless interface function according to the CSMA / CA method, and the operation is the same as the operation performed by a known wireless transmitting / receiving device. It is omitted in the flowchart. Also, it is conceivable that identification of the communication partner is performed using a known address used in the data link layer, the network layer, or other layers.

  The wireless transmitting / receiving unit 101 delivers the message received from the mobile wireless communication device 200 to the message receiving unit 102. The message receiving unit 102 of the fixed wireless communication device 100 checks whether the mobile wireless communication device 200 periodically receives a periodic message transmitted to the fixed wireless communication device 100 or by broadcast (S100). Here, the periodic message is a message including device information such as an identifier capable of identifying the mobile wireless communication device 200, the position of the mobile wireless communication device 200, the moving speed, the moving direction, and the like. When there is the received periodic message, the device information included in the message received by the message recording unit 103 is recorded for each mobile radio communication device 200 (S110). In this embodiment, a mobile corresponding to the mobile radio communication apparatus 200 in which the fixed radio communication apparatus 100 records the apparatus information constitutes a target selection group of readers. The device information may be deleted from the message recording unit 103 by aging or the like.

  Next, the reader candidate determination unit 105 refers to the device information of each mobile radio communication device 200 held by the message recording unit 103, and based on the information such as the position and speed of the mobile radio communication device 200, the mobile radio concerned. Mode determination is performed as to whether or not it is possible to make a mobile equipped with the communication device 200 a leader candidate (S120). Note that one or more mobile units may be selected as leader candidates. As an example of a specific determination method of this mode determination, the position of the mobile wireless communication device 200 is acquired from the periodic message, and the mobile wireless communication device 200 exists at a position where it can easily operate as a reader, or operates as a reader There is a method of discriminating by discriminating whether the mobile radio communication device 200 exists in a position where it is difficult to do. For example, in the case of cooperative operation of vehicles at the time of vehicle merging from a merging lane to a main line (traveling lane and overtaking lane) on a highway etc. shown in FIG. 10 described later, first travel on the traveling lane where merging vehicles merge It can be considered that the vehicle is easy to operate as a leader device, and the vehicle traveling in the overtaking lane is difficult to operate as a leader according to the position. Furthermore, when the vehicle speed is higher than that of other vehicles, it may be considered that the vehicle is determined to be unsuitable as a leader.

  Next, the reception timing recording unit 104 records the reception timing of the periodic message for each mobile radio communication apparatus 200 (S103). Then, the transmission timing determination unit 106 obtains the reception interval obtained from the reception timing of the periodic message held by the reception timing recording unit 104 (after receiving the periodic message from one mobile radio communication apparatus 200 last time, Based on the time until reception, the transmission timing to be assigned to each mobile radio communication apparatus 200 is determined (S140). As a specific example of the method of determining the transmission timing, for example, it is possible to use the maximum value of the reception interval of the periodic message from the mobile radio communication device 200 within a fixed time as the time length (transmission time length) that can be used for transmission There is a method of allocating time slots having a transmission time length defined in the communication apparatus 200 so as not to overlap one time slot at a time. Alternatively, a predetermined number of mobile wireless communication devices 200 can be provided such that a time slot length is predetermined and a transmission time length equal to or greater than the maximum value of the reception interval of periodic messages from each mobile wireless communication device 200 is given. One possible way is to allocate time slots. As a method of designating the allocated transmission timing to the mobile radio communication apparatus 200, a method of designating by using an absolute time shared in the device, a method of designating by using an elapsed time from the received timing, and the like can be considered.

  Next, the message transmission unit 107 determines whether the event detection unit 110 is notified of detection of an event serving as a trigger for starting reader selection (S160). When the periodic message is not received in the process of S100, the process of S160 is performed after the process of S100. When occurrence of an event is notified in the process of S160, the message creation unit 108 creates a leader selection start message (S170). Here, the reader selection start message includes mode information indicating whether each mobile radio communication apparatus 200 can be a reader candidate and a transmission timing assigned to each mobile radio communication apparatus 200. Then, the message creation unit 108 broadcasts the created leader selection start message (S180). A unicast message may be created and transmitted to each mobile radio communication apparatus 200 without using broadcast.

  Next, the operation of the mobile wireless communication device 200 will be described. FIG. 7 is a flow chart showing an example of the processing flow of the mobile radio communication apparatus 200 of this embodiment. The flowchart shown in FIG. 7 is an example, and if necessary, the order of processing may be changed and parallelization may be performed. Further, since the wireless transmission / reception unit 201 and the antenna 209 provide the wireless interface function by the CSMA / CA method as the wireless transmission / reception unit 101 and the antenna 109 of the fixed wireless communication device 100, they are omitted in the flowchart of FIG. ing.

  The message transmission unit 206 of the mobile radio communication device 200 transmits a periodic message each time the prescribed period expires (S210). As described above, the periodic message is a message including device information such as an identifier that can identify the mobile wireless communication device 200, the position of the mobile wireless communication device 200, the moving speed, and the moving direction. As an identifier capable of identifying the mobile radio communication apparatus 200, it is conceivable to use an identifier assigned to a mobile for individual identification or to use an identifier allocated to the mobile radio communication apparatus 200.

  After transmitting the periodic message, or if the prescribed period has not expired, the message reception unit 202 confirms whether or not the reader selection start message from the fixed wireless communication device 100 has been received, and selects the reader. If the start message has been received, the start of the leader selection process is determined (S220). If the leader selection process is not started, the process returns to step S210. When the start of the reader selection process is determined in the process of S220, the message reception unit 202 analyzes the content of the received reader selection start message, and the own apparatus (or a mobile unit mounting the own apparatus) is designated as a candidate reader. The mode information indicating the presence or absence and the transmission timing assigned by the fixed wireless communication apparatus 100 are extracted, and the mode switching unit 203 is notified of the mode information and the transmission timing is notified to the message transmission unit 205 (S230).

  Next, the mode switching unit 203 determines, based on the extracted mode information, whether or not the own device is designated as a reader candidate (S240). Hereinafter, the mobile wireless communication device 200 designated as the reader candidate is also referred to as a reader candidate device, and the mobile wireless communication device 200 not designated as the reader candidate is also referred to as a reception device.

  In the mobile wireless communication device 200 of the reader candidate device, after the process of S240, the reader operation determination unit 204 confirms with the mobile control unit 210 whether or not it can operate as a reader, and operates as a reader candidate It is determined whether to do or not (S250). Note that, as described above, the moving object control unit 210 is a device that controls automatic traveling if, for example, the moving object is an automatic traveling vehicle, and whether the moving object can operate as a leader of cooperative operation is the moving object control unit 210 However, it should be judged according to each adaptation form. The present invention does not limit the determination of the reader operation of the mobile unit to a specific determination method, and the operation may be performed according to the determination of the mobile unit controller 210.

  If it is determined in S250 that the device does not operate as a reader candidate, the reader operation determination unit 204 determines that the device is not a reader (S251). On the other hand, when it is determined to operate as a reader candidate in S250, the message transmission unit 205 creates a reader proposal message (S252) and broadcasts the created reader proposal message via the wireless transmission / reception unit 201 (S252). S253). The reader proposal message includes an identifier of a reader candidate device that transmits the message and a proposal identifier that indicates a reader proposal, and the other mobile wireless communication device indicates that the device (or a mobile including the device) is a reader candidate. Message to notify

  Next, the message reception unit 202 starts a timer (S254), and waits for an acceptance response message from the mobile radio communication device 200 which is the acceptance device. The acceptance response message includes an identifier of the reader candidate device that has sent the reader proposal message and a proposal identifier that indicates that the proposal agrees with the proposal, and the reader candidate device that has sent the reader proposal message the acceptance device that has sent the acceptance response message Indicates that you have agreed to become a leader. After activating the timer, the message receiving unit 202 determines whether the activated timer has expired (S255). If the timer has not expired, then the message reception unit 202 checks whether or not an acceptance response message has been received from another mobile radio communication device 200 (S256).

  If the acceptance response message has been received in the process of S256, it is next determined whether the number of acceptance response messages received by the mode switching unit 203 has become equal to or greater than a specified value (S257). Here, a majority of the number of mobile radio communication devices 200 of the reception device in the group is taken as the predetermined value as an example of the predetermined value. The number of mobile radio communication devices 200 of the reception device in the group can be acquired from the reader selection start message. If it is determined in the process of S257 that the number of acceptance response messages received is equal to or greater than the specified value, the reader operation determination unit 204 determines that the apparatus itself is a reader (S258).

  If it is determined in step S255 that the timer has expired, the process of step S251 is performed. If the acceptance response message is not received in the process of S256, and if the number of receptions is not equal to or more than the specified value in the process of S257, the process of S255 is performed.

  On the other hand, when it is determined in the process of S240 that the own device is not designated as a reader candidate, the message reception unit 202 starts a timer (S260), and the reader proposal from the mobile wireless communication device 200 of the reader candidate device is proposed. Listen for messages After activating the timer, the message receiving unit 202 determines whether the activated timer has expired (S261). If the timer has not expired, then the message reception unit 202 determines whether the reader proposal message transmitted from the mobile radio communication apparatus 200 of the reader candidate apparatus has been received (S262).

  Then, if the reader proposal message has been received, next, the message reception unit 202 determines whether the received reader proposal message is the first reader proposal message (S263). If the received reader proposal message is the first reader proposal message, then the message transmission unit 205 generates an acceptance response message. As described above, the acceptance response message is a message indicating that the reader candidate device that has transmitted the received reader proposal message has agreed to become a reader. Here, although the acceptance response message is generated in response to the reader proposal message received first, the method of determining the reader candidate device to which the acceptance response message is to be returned is not limited to this, and it may be determined based on another criterion. Good. Then, the message transmission unit 205 waits for the transmission timing notified in the process of S230 (S265), and transmits the created message (S266).

  After the process of S266, the process of S261 is performed again. If it is determined that the reader proposal message has not been received in S262, the process of S261 is performed again if it is determined that the reader proposal message received in S263 is not the first reader proposal message. When the expiration of the timer is determined in the process of S261, the reader operation determination unit 204 determines that the apparatus is not a leader (S267).

  When the mobile radio communication apparatus 200 operates as described above, the mobile radio of the reader candidate apparatus which receives an acceptance response message from a majority of the mobile radio communication apparatuses 200 among the mobile radio communication apparatuses 200 that are reception apparatuses in the group Since there is only one communication device 200, it is guaranteed that there is only one reader in the group.

FIG. 8 is a timing diagram showing a specific example of transmission timing determination performed by the fixed wireless communication device 100 in the process of S140. Here, it is assumed that the mobile wireless communication apparatus 200 ₁ and the mobile radio communication apparatus 200 ₂ shown in FIG. 1 was chosen reader candidate device. The numbers shown in each time slot in FIG. 8 correspond to the code of each mobile radio communication apparatus 200, and indicate which mobile radio communication apparatus 200 each time slot is assigned. In this example, after allocating a slot in the mobile radio communication device 200 _1, the leader candidate device, allocates a different slot each mobile wireless communication device 200 ₃ -200 ₆ is a receiving apparatus, a mobile radio and more reader candidate device after assigning time slots to the communication unit 200 _2, by assigning each mobile wireless communication device 200 ₃ -200 ₆ is a receiving apparatus different time slots, which specify the transmission timing of each mobile wireless communications device 200. In this way, it is possible to specify non-overlapping transmission timings for each mobile radio communication apparatus 200.

FIG. 9 is a timing diagram illustrating another example of transmission timing determination. 9 and the mobile radio communication apparatus in the same manner 200 ₁ and the mobile radio communication device 200 ₂ is assumed to have been selected as the reader candidate device. In this example, first specify the transmission timing assigned to successive time slots to the mobile radio communication apparatus 200 ₁ and the mobile radio communication device 200 _{and second} reader candidate device, mobile wireless communication device 200 ₃ -200 subsequent to receiving device _A time slot is assigned to ₆ to specify transmission timing.

  As described above, the transmission timing of each mobile radio communication apparatus 200 is specified based on the periodic message transmitted from the mobile radio communication apparatus 200 installed in the mobile unit of which the fixed radio communication apparatus 100 configures a group, Since the mobile radio communication apparatus 200 transmits the message at the transmission timing specified by the fixed radio communication apparatus 100, the determination of the transmission timing of the response to the transmission request can be made with a small overhead, and the CSMA / CA scheme In a reader selection system using wireless communication, it is possible to reduce the probability that a message is lost due to a packet collision due to a hidden terminal problem, and it is possible to select a reader with high probability.

  Furthermore, fixed radio communication apparatus 100 selects one or more reader candidate apparatuses from mobile radio communication apparatuses 200 in the group, and determines a reader by voting from another mobile radio communication apparatus 200 in the group. It becomes possible to determine only one reader by setting the reference as a reader candidate device obtained by voting from a majority of mobile wireless communication devices 200 that are not leader candidate devices in the group.

  Below, the specific example of application of the leader election system of this embodiment is explained. FIG. 10 is a schematic diagram showing an operation example in the case where the leader selection system according to this embodiment is applied to the selection of a vehicle serving as a leader in order to realize the coordinated operation required for an automatic traveling vehicle. FIG. 10 shows an example of securing a space for a merging vehicle by cooperative operation of the vehicles at a location where a vehicle traveling on the merging lane merges with the main line. The arrow in FIG. 10 indicates the traveling direction of the vehicle. The fixed wireless communication device 100 is a roadside device. The mobile radio communication device 200 is mounted on a vehicle, and transmits device information (vehicle information) including the identifier, the position, and the speed of the vehicle as a periodic message. The roadside apparatus (fixed wireless communication apparatus 100) receives the periodic message transmitted from the vehicle (mobile wireless communication apparatus 200), and records the vehicle information and the reception timing thereof.

Road device (fixed wireless communication device 100) detects that the merging vehicle from the event detection unit 110 (not shown in FIG. 10) (equipped with a mobile radio communication device 200 ₆₎ is approaching. The event detection unit 110 may install a sensor near the merging lane to detect that there is a merging vehicle. Alternatively, it may be detected by exchanging messages between the merging vehicle and the roadside apparatus. Merging vehicle (mobile radio communication device 200 ₆₎ detected roadside device (fixed wireless communication device 100), main line (the traveling lane and TsuiEtsu lane) equipped vehicle (each mobile wireless communication device 200 ₁ -200 ₅ that travels And determines whether each mobile radio communication apparatus 200 is to be a reader candidate apparatus, assigns a transmission timing, and transmits a reader selection start message. Examples of a method of determining the reader candidates from a plurality of vehicles (mobile communication apparatus 200), in the case of performing cooperatively the merging space ensuring operation as shown in FIG. 10, the travel of the merging vehicle 200 ₆ flows Since it is considered that smooth coordination can be achieved by using a vehicle traveling in a lane as a leader, a method of making a vehicle in a traveling lane a leader candidate can be considered. Criteria for selecting a leader candidate may be determined according to the application of the present invention.

Then, the mobile radio communication apparatus 200 that has received the reader selection start message carries out the processing of the processing flow of the above-mentioned mobile radio communication apparatus 200, and selects the reader's vehicle. By setting the leader, for example, the vehicle which has become the leader can secure a space, and the smooth space can be secured. In addition, it is not necessary to necessarily include a joining vehicle in a group, and you may make only the vehicle which drive | works a main line into the object of leader selection.
Second Embodiment

  In fixed wireless communication apparatus 100 and mobile wireless communication apparatus 200 shown in the first embodiment, when it is necessary to use the function of the wireless interface for applications other than reader selection, mobile wireless communication apparatus while changing the application. It can not be used as the transmission timing assigned to 200. In this embodiment, a fixed wireless communication device 100 that addresses this problem will be described.

  The configuration of fixed wireless communication apparatus 100 of this embodiment is the same as that of the first embodiment. When there is a time that can not be used for reader selection, fixed wireless communication apparatus 100 according to this embodiment assigns the transmission timing to each mobile wireless communication apparatus 200 in consideration of the time, and the fixed wireless communication according to the first embodiment Unlike the device 100, the same operation is performed in other points. Note that the time that can not be used for leader election may be determined in advance, or may be acquired by receiving a notification from the mobile radio communication device 200.

  FIG. 11 is a timing diagram showing an example of transmission timing assignment determined by the fixed wireless communication device 100 of this embodiment. As shown in FIG. 11, when there is time that can not be used for leader election, the time slot length is adjusted and transmission timing is allocated so that the time that can be used for transmission excluding the time that can not be used becomes a predetermined transmission time length. To be able to

  According to this embodiment, even when there is a time when the function of the wireless interface can not be used for leader election, transmission timing can be assigned to each mobile radio communication device 200, so that leader election is successful. The probability can be improved.

Third Embodiment
In this embodiment, an example in which the fixed wireless communication device 100 has an information distribution function for the mobile wireless communication device 200 will be described. Fixed wireless communication apparatus 100 according to this embodiment assigns a transmission timing to each mobile wireless communication apparatus 200 excluding the time for implementing information distribution as in the second embodiment. Then, the fixed wireless communication device 100 performs information distribution at the time excluded from the transmission timing assignment.

  FIG. 12 is a timing diagram showing an example of transmission timing determination performed by the fixed wireless communication device 100 of this embodiment. As shown in FIG. 12, when there is an information delivery time that can not be used for leader selection, the time slot length is adjusted so that the time that can be used for transmission excluding the unavailable time becomes a predetermined transmission time length and transmission timing To be assigned.

  In the present embodiment, the assignment of the transmission opportunity taking into consideration the information delivery time can improve the success probability of the leader selection and prevent the occurrence of a delay in the information delivery from the fixed wireless communication device 100. .

  According to the fixed wireless communication device and the mobile wireless communication device of the present invention, when the possibility of the collision of the wireless signal due to the hidden terminal problem of the CSMA / CA system is reduced and the leader is selected by voting using the wireless communication. This is useful for a leader election system using the CSMA / CA scheme because it can reduce the possibility of a leader election failure.

100 fixed wireless communication devices, 200, 200 ₁ , 200 ₂ , 200 ₃ , 200 ₄ , 200 ₅ , 200 ₆ mobile wireless communication devices, 101 wireless transmission / reception units, 102 message reception units, 103 message recording units, 104 reception timing recording units 105 reader candidate determination unit 106 transmission timing determination unit 107 message transmission unit 109 antenna 110 event detection unit 120 processor 121 storage 122 memory 123 transceiver 201 wireless transmission / reception unit 202 message reception unit 203 mode Switching unit, 204 reader operation determination unit, 205 message transmission unit, 209 antenna, 210 mobile unit control unit, 220 processor, 221 storage, 222 memory, 223 transceiver.

Claims (6)

A reader is selected from the plurality of mobile bodies by wireless communication of a CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) system including a fixed radio communication device and a plurality of mobile radio communication devices respectively mounted on a plurality of mobile bodies. Said fixed wireless communication device in a system
A message receiver for receiving a periodic message periodically transmitted from the mobile radio communication device;
A reception timing recording unit that records the reception timing of the periodic message;
A transmission timing determination unit that allocates transmission timing to each of the mobile radio communication devices based on the reception timing of the periodic message;
A leader candidate determination unit that determines the mobile unit to be a leader candidate from among the mobile units mounted with the mobile radio communication apparatus that is a transmission source of the received periodic message;
A message transmission unit for generating a vote request message for notifying the mobile radio communication apparatus of the start of voting for leader selection and the transmission timing allocated to the mobile unit of the leader candidate;
A fixed wireless communication device comprising:   The transmission timing determination unit determines a transmission time length that can be used for transmission based on the maximum value of the reception interval of consecutive periodic messages from the same mobile radio communication device in the allocation of the transmission timing, and the transmission time The fixed wireless communication device according to claim 1, wherein time slots having a length are assigned to each of the mobile wireless communication devices.   The transmission timing determination unit is configured such that, when there is a time that can not be used for reader selection radio communication in the transmission timing assignment, the time that can be used for transmission excluding the time that can not be used becomes the transmission time length. The fixed wireless communication apparatus according to claim 2, wherein the length of the time slot is adjusted.   The transmission timing determination unit transmits transmission timings to the mobile radio communication device of the mobile unit of one leader candidate next to the mobile unit that is not the leader candidate when there are a plurality of mobile units of leader candidates. A timing is allocated, and a transmission timing is allocated to the mobile radio communication device of the mobile unit of another leader candidate, and a transmission timing is further allocated to the mobile unit which is not the next leader candidate. Fixed wireless communication device.   The transmission timing determination unit transmits transmission timings to the mobile radio communication devices of the mobile units of the plurality of leader candidates next to the mobile unit that is not the leader candidate when there are a plurality of mobile units of the leader candidate. The fixed wireless communication device according to claim 1, wherein timing is assigned. A reader is selected from the plurality of mobile bodies by wireless communication of a CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) system including a fixed radio communication device and a plurality of mobile radio communication devices respectively mounted on a plurality of mobile bodies. Said mobile radio communication device in a system
A message receiving unit for receiving messages from the fixed wireless communication device and another mobile wireless communication device;
When a vote request message indicating the leader election voting start, the leader candidate mobile and the assigned transmission timing is received from the fixed wireless communication device, the own device operates as the leader candidate based on the vote request message. A reader operation determination unit that determines whether to
A periodic message is generated and transmitted in a predetermined cycle, and a reader proposal message is generated to notify another mobile wireless communication device that the own device is a reader candidate when the own device operates as a reader candidate. If the device itself does not operate as a reader candidate and receives a reader proposal message from another mobile radio communication device, the mobile radio communication device is accepted as a reader for at most one mobile radio communication device. A message sending unit that creates an acceptance response message that notifies the user, and sends the created message at the transmission timing indicated in the voting request message;
A mobile radio communication device comprising:

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