JP2010258887A - Access control apparatus, terminal device and wireless communication system utilizing them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for suppressing a packet signal collision probability from increasing even when the number of wireless apparatuses is increased. <P>SOLUTION: An extraction section 164 receives packet signals from a plurality of terminal devices, respectively, during a first term, wherein first-type terminal devices mounted in vehicles and second-type terminal devices carried with pedestrians are mixed as notification sources of a plurality of packet signals received. A summarization section 168 summarizes positional information included in each of the packet signals received. A modulation/demodulation section 154, an RF section 152 and an antenna 150 report the packet signal including the positional information summarized during a second term different from the first term. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication technique, and more particularly, to an access control device and a terminal device that transmit a packet signal including position information, and a wireless communication system using them.

  In order to prevent collision accidents such as encounters at intersections, it is effective to make the driver of another vehicle recognize the position of the own vehicle and to make the driver of the own vehicle recognize the position of the other vehicle. Specifically, a wireless device is mounted on each vehicle, and packet signals including current position information detected by a GPS (Global Positioning System) are exchanged between the wireless devices. Based on the position information included in the packet signal, the driver recognizes that another vehicle will enter the intersection. Further, the wireless device carried by the pedestrian can also recognize the presence of the pedestrian by transmitting the packet signal including the position information (see, for example, Patent Document 1).

JP 2008-217429 A

  If the wireless device is not only mounted on the vehicle but also carried by the driver, the number of wireless devices existing near the intersection increases. Therefore, the traffic volume increases and the packet signal collision probability also increases. As a result, data included in the packet signal is not transmitted to other wireless devices. If such a situation occurs, the objective of preventing a collision accident at the intersection encounter will not be achieved. Even when the number of wireless devices increases, it is desirable to suppress an increase in the collision probability of packet signals.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for suppressing an increase in the collision probability of packet signals even when the number of radio apparatuses increases.

  In order to solve the above-described problem, an access control device according to an aspect of the present invention includes a receiving unit that receives a packet signal from each of a plurality of terminal devices and a packet signal received by the receiving unit in a first period. An aggregating unit for aggregating the included position information, and a notifying unit for informing the packet signal including the position information aggregated in the aggregating unit in a second period different from the first period. The notification source of the plurality of packet signals received by the receiving unit is a mixture of the first type terminal device mounted on the vehicle and the second type terminal device carried by the pedestrian.

  Another aspect of the present invention is a terminal device. The apparatus includes an acquisition unit that acquires position information, a notification unit that notifies a packet signal including the position information acquired by the acquisition unit in a first period, and an access control that receives the packet signal notified by the notification unit A packet including position information aggregated in the access control apparatus in a second period different from the first period from the access control apparatus that has received the packet signal from the other terminal apparatus A receiving unit that receives a signal and a processing unit that processes a packet signal received by the receiving unit. The processing unit is configured to extract a plurality of pieces of position information included in the packet signal received by the receiving unit, and a plurality of pieces of position information extracted by the extracting unit from the position information acquired by the acquiring unit within a predetermined range An instructing unit that causes the notifying unit to stop informing the packet signal when the position information is present.

  Yet another aspect of the present invention is a wireless communication system. The wireless communication system includes a plurality of first type terminal devices corresponding to the first wireless communication system and a plurality of second type corresponding to a second wireless communication system different from the first wireless communication system. A terminal device, and a first type access control device that receives a packet signal from each of a plurality of first type terminal devices and including position information of each first type terminal device; And a second type access control device for receiving a packet signal from each of the plurality of second type terminal devices and including the position information of each second type terminal device. The first type access control device notifies the aggregation result of the position information included in each packet signal received by the second type access control device by the packet signal, and the second type access control device An aggregation result of position information included in each packet signal received by one type of access control device is notified by a packet signal, and a plurality of first type terminal devices receive packets from the first type access control device. The plurality of second type terminal apparatuses receive the packet signal from the second type access control apparatus.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, an increase in the collision probability of packet signals can be suppressed even if the number of wireless devices increases.

It is a figure which shows the structure of the communication system which concerns on the Example of this invention. It is a figure which shows the structure of the access control apparatus of FIG. FIGS. 3A and 3B are diagrams illustrating the format of a frame generated by the frame generation unit of FIG. It is a figure which shows the structure of the terminal device which concerns on the Example of this invention. It is a sequence diagram which shows the alerting | reporting procedure of the packet signal in the communication system of FIG. It is a flowchart which shows the determination procedure of the notification stop of the packet signal in the terminal device of FIG. It is a flowchart which shows another determination procedure of the notification stop of the packet signal in the terminal device of FIG. 6 is a flowchart showing yet another determination procedure for stopping the notification of packet signals in the terminal device of FIG. 4. It is a sequence diagram which shows the notification procedure of the stop command in the communication system of FIG. It is a figure which shows the structure of the communication system which concerns on the modification of this invention. It is a figure which shows the structure of the 1st type access control apparatus of FIG. It is a sequence diagram which shows the alerting | reporting procedure of the packet signal in the communication system of FIG. It is a figure which shows the structure of the communication system which concerns on another modification of this invention. It is a figure which shows the structure of the 1st type access control apparatus of FIG. It is a sequence diagram which shows the alerting | reporting procedure of the packet signal in the communication system of FIG.

  Before describing the present invention in detail, an outline will be described. Embodiments of the present invention relate to a communication system that performs data communication between a terminal device mounted on a vehicle and a terminal device carried by a pedestrian. The terminal device broadcasts and transmits a packet signal storing information such as a moving speed and a position (hereinafter referred to as “data”) (hereinafter, the packet signal storing the data may be referred to as “data”). On the other hand, the terminal device receives a packet signal broadcast by another terminal device and recognizes the approach of another vehicle or other pedestrian in which the other terminal device is mounted based on the data. . When the pedestrian carries the terminal device, the number of terminal devices at the intersection increases as compared with the case where the terminal device is mounted only on the vehicle. As a result, the collision probability of the packet signal increases, and it becomes difficult for the terminal device to receive the packet signal. In order to cope with this, the following processing is executed in the present embodiment.

  The communication system according to the present embodiment includes an access control device in addition to a plurality of terminal devices, and the access control device is installed at an intersection, for example. The access control apparatus repeatedly defines a frame including a plurality of slots. Further, the access control apparatus reserves a predetermined slot as a control slot, and broadcasts a packet signal storing control information (hereinafter also referred to as “control information”) in the control slot. The control information includes information for identifying the access control device (hereinafter referred to as “identification information”). The terminal device generates a frame corresponding to the control information by receiving the control information. The terminal device identifies a control slot and a slot other than the control slot among a plurality of slots included in the frame. In the following description of the terminal device, a slot may indicate a slot excluding a control slot.

  The terminal apparatus estimates a slot (hereinafter referred to as “empty slot”) that is not used by another terminal apparatus by performing carrier sense for each of the plurality of slots. The terminal device selects one slot to be used for transmitting data from the empty slots using a predetermined algorithm. The terminal device broadcasts data in the selected slot. The access control device receives data from each of the plurality of terminal devices and aggregates position information included in each data. The access control apparatus stores the aggregated position information in the control information and broadcasts it. Each terminal device can receive position information from other terminal devices only by receiving control information.

  FIG. 1 shows a configuration of a communication system 100 according to an embodiment of the present invention. This corresponds to a case where one intersection is viewed from above. The communication system 100 includes a first vehicle 12a, a second vehicle 12b, a third vehicle 12c, a fourth vehicle 12d, a fifth vehicle 12e, a sixth vehicle 12f, and a seventh vehicle 12g, which are collectively referred to as the access control device 10 and the vehicle 12. The eighth vehicle 12h, the first pedestrian 16a, the second pedestrian 16b, the third pedestrian 16c, the fourth pedestrian 16d, the fifth pedestrian 16e, the sixth pedestrian 16f, 7 pedestrians 16g, 8th pedestrian 16h, and 9th pedestrian 16i are included. Each vehicle 12 is equipped with a terminal device (not shown), and each pedestrian 16 carries a terminal device (not shown). Further, an area 200 is formed by the access control device 10.

  As shown in the drawing, the road that goes in the horizontal direction of the drawing, that is, the left and right direction, intersects the vertical direction of the drawing, that is, the road that goes in the up and down direction, at the center. Here, the upper side of the drawing corresponds to the direction “north”, the left side corresponds to the direction “west”, the lower side corresponds to the direction “south”, and the right side corresponds to the direction “east”. The intersection of the two roads is an “intersection”. The first vehicle 12a and the second vehicle 12b are traveling from left to right, and the third vehicle 12c and the fourth vehicle 12d are traveling from right to left. Further, the fifth vehicle 12e and the sixth vehicle 12f are traveling from the top to the bottom, and the seventh vehicle 12g and the eighth vehicle 12h are traveling from the bottom to the top. The first pedestrian 16a to the ninth pedestrian 16i exist near the intersection.

  A terminal device mounted on each vehicle 12 or a terminal device carried by each pedestrian 16 acquires data and broadcasts a packet signal in which the data is stored. Here, before explaining a modified example of the present invention, an operation when the terminal device is compatible with a known wireless LAN, that is, when CSMA / CA is supported will be described. Each terminal device broadcasts and transmits data when it is determined that transmission is possible by executing carrier sense. Therefore, data from a plurality of terminal devices may collide. Moreover, the probability of occurrence of a collision increases as the number of terminal devices increases. In particular, in places such as intersections, where collisions between the vehicles 12 and between the vehicles 12 and the pedestrians 16 are likely to occur, data collisions are likely to occur and data is required. In this case, data will not be used. In addition, data is not received even if a shielding object exists between the terminal devices.

  Therefore, the communication system 100 arranges the access control device 10 at a high place such as a traffic light at an intersection. The high place means a place higher than the height of the vehicle 12. The access control device 10 generates a frame including a plurality of slots so as to be repeated based on a signal received from a GPS satellite (not shown). Here, some of the plurality of slots are used as control slots. The access control device 10 broadcasts control information in the control slot. The plurality of terminal apparatuses receive the control information notified by the access control apparatus 10 and generate a frame based on the control information. As a result, the frame generated in each of the plurality of terminal devices is synchronized with the frame generated in the access control device 10.

  In addition, slots generated in each of the plurality of terminal devices are synchronized with each other. The terminal device performs carrier sense in each of the plurality of slots and estimates an empty slot. Further, the terminal device selects one slot from the empty slots using a predetermined algorithm. Further, the terminal device broadcasts data in the selected slot. The access control device 10 aggregates the position information included in each data, includes the aggregated position information in the control information, and notifies the control information. The terminal device continues to select slots having the same relative timing within the frame over a plurality of frames. In addition, even if it is a case where control information is not received, a terminal device may alert | report data. This corresponds to a case where the terminal device does not exist in the area 200 formed by the access control device 10. At that time, the terminal apparatus executes CSMA / CA. Even if the terminal device cannot receive data from another terminal device, if the terminal device can receive control information from the access control device 10, it recognizes the position information of the vehicle 12 or the pedestrian 16 in which the other terminal device is mounted. .

  FIG. 2 shows the configuration of the access control apparatus 10. The access control device 10 includes an antenna 150, an RF unit 152, a modem unit 154, a processing unit 156, a GPS positioning unit 158, a frame generation unit 160, and a control unit 162. The processing unit 156 includes an extraction unit 164, a classification unit 166, and an aggregation unit 168. The GPS positioning unit 158 receives a signal from a GPS satellite (not shown), and acquires time information based on the received signal. In addition, since a well-known technique should just be used for acquisition of the information of time, description is abbreviate | omitted here. The GPS positioning unit 158 outputs time information to the frame generation unit 160.

  The frame generation unit 160 acquires time information from the GPS positioning unit 158. The frame generation unit 160 generates a plurality of frames based on the time information. For example, the frame generation unit 160 generates 10 frames of “100 msec” by dividing the period of “1 sec” into 10 with reference to the timing of “0 msec”. By repeating such processing, the frame is defined to be repeated. The frame generation unit 160 generates a plurality of slots by dividing each frame into a plurality of frames. For example, by dividing each frame into 200, 200 “500 μsec” slots are generated.

  Here, some of the plurality of slots included in the frame are reserved as “control slots”. For example, of the 200 slots included in one frame, the two slots from the beginning are set as control slots. The control slot is a slot used for the access control apparatus 10 to broadcast control information. Further, the remainder of the plurality of slots included in the frame is secured for a terminal device (not shown) to transmit data to the access control device 10. Note that such a control slot arrangement is known to the terminal device.

  FIGS. 3A to 3B show the format of a frame generated by the frame generation unit 160. FIG. FIG. 3A shows the structure of the frame. As shown in the figure, it is defined that a plurality of frames are repeated such as the i-th frame to the (i + 2) -th frame. The period of each frame is “100 msec”, for example. FIG. 3B shows the configuration of one frame. As shown in the figure, one frame is composed of M slots. For example, M is “200”, and the period of each slot is “500 μsec”. A slot arranged at the head portion of the frame corresponds to a control slot. Here, two slots, the first slot and the second slot, are defined as the aforementioned control slots. Returning to FIG.

  As reception processing, the RF unit 152 receives a packet signal from another terminal device (not shown) by the antenna 150 in each slot. Here, when it is stipulated that a frame including a plurality of slots as shown in FIG. 3 (a) is repeated, data is transmitted at a frame period in a slot selected from the plurality of slots. Informed. Further, the data includes the identification number of the terminal device that is the notification source. Therefore, the RF unit 152 receives data from the terminal device at a frame period. The RF unit 152 performs frequency conversion on a radio frequency packet signal received via the antenna 150 to generate a baseband packet signal. Further, the RF unit 152 outputs a baseband packet signal to the modem unit 154. In general, baseband packet signals are formed by in-phase and quadrature components, so two signal lines should be shown, but here only one signal line is shown for clarity. Shall be shown.

  The RF unit 152 also includes an LNA (Low Noise Amplifier), a mixer, an AGC, and an A / D conversion unit. As a transmission process, the RF unit 152 performs frequency conversion on the baseband packet signal input from the modem unit 154 in each slot to generate a radio frequency packet signal. Further, the RF unit 152 transmits a radio frequency packet signal from the antenna 150. The RF unit 152 also includes a PA (Power Amplifier), a mixer, and a D / A conversion unit.

  The modem unit 154 performs demodulation on the baseband packet signal from the RF unit 152 as reception processing. Further, the modem unit 154 outputs the demodulated result to the processing unit 156. Further, the modem unit 154 performs modulation on the data from the processing unit 156 as a transmission process. Further, the modem unit 154 outputs the modulated result to the RF unit 152 as a baseband packet signal. Here, when the communication system 100 is compatible with the OFDM modulation scheme, the modem unit 154 also executes FFT (Fast Fourier Transform) as a reception process and IFFT (Inverse Fast Fourier Transform) as a transmission process.

  The processing unit 156 receives information about the timing of the frame and the timing of the slot included in the frame from the frame generation unit 160. The processing unit 156 identifies the timing of the control slot among the plurality of slots included in the frame. In the case of FIG. 3B, two control slots, the first slot and the second slot, are specified. As a result of specifying the control slot, slots other than the control slot included in the frame are also specified. The processing unit 156 receives a packet signal from each terminal device in each slot other than the control slot in the frame. The notification source of the plurality of packet signals received by the processing unit 156 includes a terminal device mounted on the vehicle 12 (hereinafter referred to as “first type terminal device”) and a terminal device carried by the pedestrian 16 (hereinafter referred to as “terminal device”). "Type 2 terminal device").

  The extraction unit 164 extracts position information, type information, and speed information from the received packet signal. Here, the type information is information for identifying the first type terminal device and the second type terminal device. The extraction unit 164 outputs the extracted combination of information to the classification unit 166. The classification unit 166 receives a combination of information extracted by the extraction unit 164. Here, as many combinations as the number of terminal devices are input. The classification unit 166 classifies the position information about the first type terminal device and the position information about the second type terminal device based on the type information included in each combination. That is, the classification unit 166 generates one combination (hereinafter referred to as “first combination”) from the position information for the first type terminal device, and another combination (hereinafter referred to as “first type” from the position information for the second type terminal device. 2 combinations ”). The classification unit 166 outputs the first combination and the second combination to the aggregation unit 168.

  The aggregation unit 168 receives the first combination and the second combination from the extraction unit 164. In addition, the aggregation unit 168 stores the first combination and the second combination in separate packet signals. The aggregating unit 168 assigns the packet signal storing the first combination to the control slot arranged at the head of the frame. In addition, the aggregation unit 168 assigns a packet signal storing the second combination to the control slot arranged second in the frame. This corresponds to assigning the position information from the terminal device mounted on the vehicle 12 and the position information of the terminal device carried by the pedestrian 16 to the packet signals arranged in different control slots.

  The modem unit 154 and the RF unit 152 broadcast-transmit the packet signal storing the first combination from the antenna 150 in the first control slot. In addition, the modem unit 154 and the processing unit 156 broadcast the packet signal storing the second combination from the antenna 150 in the second control slot. This is equivalent to separately reporting the packet signal in which the position information about the type 1 terminal apparatus is aggregated and the packet signal in which the position information about the type 2 terminal apparatus is aggregated in the control slot period. . These packet signals correspond to the control information described above.

  The destination of the control information is the first type terminal device and the second terminal device. The terminal device that has received the control information recognizes the timing of each slot, and uses at least one of the slots reserved for communication between the terminal devices. Further, when the terminal apparatus broadcasts data over a plurality of frames, the terminal apparatus may use slots having the same relative timing within the frame. The control unit 162 controls processing of the access control apparatus 10 as a whole.

  If the quality of the data received by the modem 154 is worse than the threshold value, and the predetermined number or more of the deteriorated data is included in the frame, the processing unit 156 has too much traffic. Is determined. At this time, the processing unit 156 includes in the control information a command for stopping transmission to the terminal device (hereinafter referred to as “stop command”). The modem 154, the RF unit 152, and the antenna 150 broadcast control information including a stop command (hereinafter also referred to as “stop command”). The terminal device that has received the stop command stops data broadcast transmission. The stop period may be determined in advance or may be indicated by control information.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it can be realized by a program loaded in the memory, but here it is realized by their cooperation. Draw functional blocks. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  FIG. 4 shows a configuration of the terminal device 14 according to the embodiment of the present invention. The terminal device 14 includes an antenna 50, an RF unit 52, a modem unit 54, a processing unit 56, and a control unit 58. The processing unit 56 includes a timing specifying unit 60, an acquiring unit 62, a generating unit 64, a notification unit 70, a receiving unit 72, and an instruction unit 74. The timing specifying unit 60 includes a control information extracting unit 66 and a slot determining unit 68. including. The terminal device 14 corresponds to the above-described first type terminal device and second type terminal device. The antenna 50, the RF unit 52, and the modem unit 54 perform the same processing as the antenna 150, the RF unit 152, and the modem unit 154 in FIG. Therefore, these descriptions are omitted here.

  The acquisition unit 62 includes a GPS receiver (not shown), a gyroscope, a vehicle speed sensor, and the like, and acquires the location, traveling direction, moving speed, and the like of the vehicle 12 and the pedestrian 16 (not shown) based on data supplied from them. To do. The existence position is indicated by latitude and longitude. Here, the presence position of the vehicle 12 is acquired in the case of the first terminal device, and the presence position of the pedestrian 16 is acquired in the case of the second type terminal device. Since a known technique may be used for these acquisitions, description thereof is omitted here. The acquisition unit 62 outputs the acquired information to the generation unit 64.

  The control information extraction unit 66 receives the demodulation result from the modem unit 54. Further, the control information extraction unit 66 recognizes that the slot containing the control information, that is, the control slot is received by monitoring the demodulation result. For example, the control information includes a predetermined unique word, and the control information extraction unit 66 recognizes reception of the control slot when the unique word is detected by the correlation process. Further, the control information extraction unit 66 establishes frame and slot synchronization with reference to the timing at which the slot including the control information is received.

  More specifically, the control information extraction unit 66 generates a frame based on the detected control slot. Since the control slot corresponds to, for example, the first slot in FIG. 3B, the control information extraction unit 66 generates a frame with reference to the first slot. That is, the control information extraction unit 66 generates a frame including a plurality of slots so as to synchronize with the frame corresponding to the control slot. This corresponds to the control information extraction unit 66 extracting information regarding the timing of the frame and the timing of the slot included in the frame from the control information. The control information extraction unit 66 outputs information regarding the generated frame to the slot determination unit 68.

  The slot determination unit 68 measures the interference power for each of the plurality of slots included in the frame generated by the control information extraction unit 66 by carrier sense. Carrier sense is performed in slots other than the control slot in the frame. Further, the slot determination unit 68 estimates an empty slot based on the interference power. More specifically, the slot determination unit 68 stores a predetermined threshold value in advance, and compares the interference power in each slot with the threshold value. Further, the slot determination unit 68 estimates a slot having interference power smaller than the threshold as an empty slot, and randomly identifies one of them. Note that the slot determination unit 68 may identify a slot with the smallest interference power. As a result, the slot determination unit 68 determines a slot that is synchronized with the control slot information and arrives at the frame period. If control information is not extracted by the control information extraction unit 66, the slot determination unit 68 determines the transmission timing by executing CSMA / CA. The slot determination unit 68 notifies the generation unit 64 of the identified slot and the determined transmission timing.

  The generation unit 64 generates data so as to include the information acquired by the acquisition unit 62. In other words, the generation unit 64 generates data including the measured presence position. The generation unit 64 also includes type information in the data. The generation unit 64 broadcasts data through the modulation / demodulation unit 54, the RF unit 52, and the antenna 50 in the slot specified by the slot determination unit 68. This corresponds to data being broadcasted at a timing based on the control information when the control information is received. On the other hand, when the control information is not received, the data is broadcasted at the transmission timing determined by the slot determination unit 68.

  The receiving unit 72 receives the packet signal via the antenna 50, the RF unit 52, and the modem unit 54. Here, the packet signal corresponds to control information and data. When the packet signal is control information, the notification source is the access control device 10 and is received in the control slot. On the other hand, the packet signal is data, and the notification source is another terminal device 14, which is received in a slot other than the control slot. The receiving unit 72 extracts position information and the like from the received packet signal. As described above, since the control information includes position information and the like aggregated in the access control apparatus 10, when the packet signal is control information, the reception unit 72 includes a plurality of positions included in the packet signal. Extract information. The receiving unit 72 outputs position information and the like to the notification unit 70 and the instruction unit 74.

  Note that the receiving unit 72 of the second type terminal device may not receive the control information arranged in the second control slot. The control signal includes position information about the second type terminal device. This position information corresponds to the position information of the pedestrian 16 in FIG. In general, even if the pedestrian 16 is not notified by the terminal device 14, the approach of other pedestrians 16 can be sufficiently confirmed with the eyes, so that reception of control information arranged in the second control slot can be omitted. It is.

  The notification unit 70 receives position information and the like from the reception unit 72 and receives current position information from the acquisition unit 62. The notification unit 70 compares the received position information and notifies the approach of another vehicle 12 or another pedestrian 16 (not shown) via a monitor or a speaker. For example, when the distance between the position information received from the reception unit 72 and the position information received from the acquisition unit 62 becomes smaller than a threshold value, the notification unit 70 notifies the approach. The driver or the pedestrian 16 notified of such information is alerted. When notifying the approach of another vehicle 12 or another pedestrian 16 on the monitor, the notification unit 70 displays an image of the other vehicle 12 or other pedestrian 16 on the map image displayed by the car navigation device. May be synthesized.

  The instruction unit 74 is included only in the second type terminal device. The instructing unit 74 receives a plurality of pieces of position information from the accepting unit 72, and selects position information of other second type terminal devices from among them. Further, the instruction unit 74 receives the current position information from the acquisition unit 62 and derives the distance between the received position information and the selected position information. This distance is derived for each other type 2 terminal device. Moreover, the instruction | indication part 74 makes the production | generation part 64 stop alerting | reporting of data, when the distance smaller than a threshold value exists, ie, when the other pedestrian 16 exists in the predetermined range from the present position. This is because, when the pedestrians 16 are densely packed, the group of the pedestrians 16 is recognized by the first type terminal device if someone performs data.

  As described above, the accepting unit 72 accepts not only control information but also data. When the instruction unit 74 continues to receive packet signals from the same second type terminal device for a predetermined period, the instruction unit 74 determines that the terminal device 14 continues to exist in the vicinity of the second type terminal device. The instruction unit 74 may cause the generation unit 64 to stop reporting the data when making such a determination. Further, the instruction unit 74 determines whether or not it is moving based on the position information from the acquisition unit 62. More specifically, the instruction unit 74 calculates a difference between position information acquired at different timings, and determines that the movement is not performed if the magnitude of the difference is included in the error range. If it has not moved for a predetermined period, the instructing unit 74 may cause the generating unit 64 to stop reporting data. The control unit 58 controls the operation of the entire terminal device 14.

  The operation of the communication system 100 configured as above will be described. FIG. 5 is a sequence diagram illustrating a packet signal notification procedure in the communication system 100. The terminal device 14 in FIG. 4 is shown as a first type terminal device 142 and a second type terminal device 144, and the first type terminal device 142 is a first type 1 terminal device 142a and a second type 1 terminal device 142b. The second type terminal device 144 is a generic term for the first type 2 terminal device 144a and the second type 2 terminal device 144b. The first type 2 terminal device 144a broadcasts a packet signal including data (S10). The first type 1 terminal device 142a broadcasts a packet signal including data (S12). The second type 2 terminal device 144b broadcasts a packet signal including data (S14).

  The second type 1 terminal device 142b broadcasts a packet signal including data (S16). The access control device 10 classifies the position information and the like into the first combination and the second combination according to the notification source of the packet signal (S18). Moreover, the access control apparatus 10 collects location information by storing the first combination in the first packet signal and storing the second combination in the second packet signal (S20). The access control apparatus 10 notifies the first packet signal (S22, S24, S26, S28) and notifies the second packet signal (S30, S32, S34, S36). Here, steps 22 to 28 are a single operation, and steps 30 to 36 are also a single operation.

  FIG. 6 is a flowchart showing a determination procedure for stopping the notification of the packet signal in the terminal device 14. The instruction unit 74 acquires position information included in the packet signal (S50). The instruction unit 74 acquires the current position information from the acquisition unit 62 (S52). The instruction unit 74 calculates the distance (S54). If the distance is within the predetermined range (Y in S56), the instruction unit 74 causes the generation unit 64 to stop the notification (S58). On the other hand, if the distance is not within the predetermined range (N in S56), the process is terminated. This corresponds to the generation unit 64 notifying the packet signal.

  FIG. 7 is a flowchart showing another determination procedure for stopping the notification of the packet signal in the terminal device 14. If the instruction unit 74 has received a packet signal from the same second type terminal device for a certain period (Y in S70), the instruction unit 74 causes the generation unit 64 to stop the notification (S72). On the other hand, when the instruction unit 74 has not received a packet signal from the same second type terminal device for a certain period (N in S70), the instruction unit 74 ends the process.

  FIG. 8 is a flowchart showing still another determination procedure for stopping the notification of the packet signal in the terminal device 14. The instruction unit 74 acquires the current position information from the acquisition unit 62 (S80), and determines whether or not it is moving (S82). If it has not moved for a certain period (Y in S84), the instruction unit 74 causes the generation unit 64 to stop notification (S86). On the other hand, when it has moved (N of S84), processing is ended.

  FIG. 9 is a sequence diagram illustrating a stop instruction notification procedure in the communication system 100. The first type 2 terminal device 144a broadcasts a packet signal including data (S100). The first type 1 terminal apparatus 142a broadcasts a packet signal including data (S102). The second type 2 terminal device 144b broadcasts a packet signal including data (S104). The second type 1 terminal apparatus 142b broadcasts a packet signal including data (S106). The access control apparatus 10 determines to stop reporting data (S108). The access control device 10 notifies a stop command (S110, S112, S114, S116).

  Next, a modification of the present invention will be described. The modification of this invention is related with the communication system containing the access control apparatus and the some terminal device similarly to the Example of this invention. In the embodiment, the terminal device includes the first type terminal device and the second type terminal device, both of which can communicate with the access control device. On the other hand, in the modification, the access control device also includes the first type access control device and the second access control device, and the first type access control device can communicate with only the first type terminal device, The second access control device can communicate only with the second type terminal device. Therefore, the first type access control apparatus collects position information about the first type terminal apparatus, and the second type access control apparatus collects position information about the second type terminal apparatus. The first type access control device and the second type access control device exchange the collected information with each other. Each of the first type access control device and the second type access control device notifies the control information as described above.

  FIG. 10 shows a configuration of a communication system 100 according to a modification of the present invention. The communication system 100 includes a first type access control device 102, a second type access control device 104, a first type terminal device 142, and a second type terminal device 144. Note that a plurality of first type access control devices 102, second type access control devices 104, first type terminal devices 142, and second type terminal devices 144 may be included, but here, in order to simplify the description , One for each.

  The first type terminal device 142 is a terminal device 14 mounted on the vehicle 12 (not shown), and the first type terminal device 142 corresponds to a predetermined wireless communication system (hereinafter referred to as “first type wireless communication system”). To do. Here, the wireless communication system includes the communication system 100, the wireless LAN system, the mobile phone system, and the like in the embodiments. The second type terminal device 144 is a terminal device 14 carried by a pedestrian 16 (not shown). The second type terminal device 144 is a radio communication system (hereinafter referred to as “second type”) different from the first type radio communication system. Corresponding to a "seed radio communication system"). The second type wireless communication system is the same wireless communication system as the first type wireless communication system, and the frequency may be different. That is, the first type wireless communication system and the second type wireless communication system may operate independently of each other.

  The first type access control apparatus 102 corresponds to the first type radio communication system, is a packet signal from each of a plurality of first type terminal apparatuses 142, and includes position information of each first type terminal apparatus 142 The received packet signal is received. The packet signal corresponds to the aforementioned data. Similar to the embodiment, the first type access control apparatus 102 aggregates position information and the like included in the packet signal, that is, position information and the like regarding the first type terminal apparatus 142. This aggregation result corresponds to the aforementioned “first combination”. The type 2 access control device 104 corresponds to the type 2 wireless communication system, is a packet signal from each of the plurality of type 2 terminal devices 144, and includes position information of each type 2 terminal device 144. The received packet signal is received. The packet signal also corresponds to the aforementioned data. Similar to the embodiment, the second type access control apparatus 104 aggregates position information and the like included in the packet signal, that is, position information and the like regarding the second type terminal apparatus 144. This aggregation result corresponds to the aforementioned “second combination”.

  The first type access control apparatus 102 and the second type access control apparatus 104 are connected by a wired network, and both exchange the aggregation results with each other. That is, the first type access control apparatus 102 outputs the first combination to the second type access control apparatus 104, and the second type access control apparatus 104 outputs the second aggregation result to the first type access control apparatus 102. . The first type access control apparatus 102 broadcasts the input second combination using a packet signal. Also, the first type access control apparatus 102 may broadcast the first combination using a packet signal. On the other hand, the second type access control apparatus 104 broadcasts the first combination using a packet signal. Also, the second type access control apparatus 104 may broadcast the second combination using a packet signal.

  Each first type terminal apparatus 142 receives a packet signal from the first type access control apparatus 102 in the first type wireless communication system. The first type terminal device 142 recognizes the positions of the vehicle 12 and the pedestrian 16 (not shown) based on the position information included in the packet signal. The type 2 terminal device 144 receives the packet signal from the type 2 access control device 104 in the type 2 wireless communication system. The second type terminal device 144 also recognizes the position of the vehicle 12 (not shown) based on the position information included in the packet signal.

  FIG. 11 shows the configuration of the first type access control apparatus 102. The first type access control apparatus 102 includes an antenna 150, an RF unit 152, a modem unit 154, a processing unit 156, a GPS positioning unit 158, a frame generation unit 160, a control unit 162, and an IF unit 170. The processing unit 156 includes an extraction unit 164 and an aggregation unit 168. The antenna 150, the RF unit 152, the GPS positioning unit 158, and the frame generation unit 160 are the same as those in FIG. Note that the antenna 150, the RF unit 152, and the modem unit 154 correspond to the first type wireless communication system and cannot communicate with the second type terminal device 144 (not shown). For the sake of brevity, it is assumed that the second type wireless communication system differs from the first type wireless communication system only in frequency. Therefore, the second type access control device 104 (not shown) is the same type as the first type access control device 102 shown in FIG.

  Similarly to FIG. 1, the extraction unit 164 extracts position information, type information, and speed information from the received packet signal. The notification source of the packet signal is the first type terminal device 142 (not shown). The extraction unit 164 outputs the combination of the extracted information to the classification unit 166. The aggregation unit 168 receives the combination of information extracted by the extraction unit 164. The aggregating unit 168 generates one combination from the position information for the first type terminal device. The generated combination corresponds to the aforementioned “first combination”. The aggregation unit 168 outputs the first combination to the IF unit 170. The IF unit 170 has a wired network interface, and is connected to the second type access control apparatus 104 (not shown) via the wired network. The IF unit 170 receives the first combination from the aggregation unit 168 and outputs the first combination to the second type access control apparatus 104. The IF unit 170 receives the second combination from the second type access control apparatus 104 and outputs the second combination to the aggregation unit 168.

  As a result, the aggregation unit 168 holds the first combination and the second combination. In addition, the aggregation unit 168 stores the first combination and the second combination in separate packet signals. The aggregating unit 168 assigns the packet signal storing the first combination to the control slot arranged at the head of the frame. In addition, the aggregation unit 168 assigns a packet signal storing the second combination to the control slot arranged second in the frame. The modem unit 154 and the RF unit 152 broadcast-transmit the packet signal storing the first combination from the antenna 150 in the first control slot. In addition, the modem unit 154 and the processing unit 156 broadcast the packet signal storing the second combination from the antenna 150 in the second control slot. The destination of the control information is the first type terminal device 142.

  The operation of the communication system 100 configured as above will be described. FIG. 12 is a sequence diagram illustrating a packet signal notification procedure in the communication system 100. The first type 2 terminal device 144a broadcasts a packet signal including data in the type 2 wireless communication system (S130). The second type 2 terminal apparatus 144b broadcasts a packet signal including data in the type 2 wireless communication system (S132). The second type access control apparatus 104 receives the packet signals from the first second type terminal apparatus 144a and the second second type terminal apparatus 144b, and aggregates the position information and the like into the second combination (S134). The first type 1 terminal apparatus 142a broadcasts a packet signal including data in the first type wireless communication system (S136). The second type 1 terminal apparatus 142b broadcasts a packet signal including data in the type 1 wireless communication system (S138). The first type access control apparatus 102 receives the packet signals from the first first type terminal apparatus 142a and the second first type terminal apparatus 142b, and aggregates position information and the like into the first combination (S140).

  The second type access control apparatus 104 notifies the first type access control apparatus 102 of the second combination (S142). The first type access control apparatus 102 notifies the second type access control apparatus 104 of the first combination (S144). The second type access control apparatus 104 notifies the first combination and the second combination by a packet signal (S146, S148). The first type access control apparatus 102 notifies the first combination and the second combination by packet signals (S150, S152). Here, Step 146 and Step 148 are single operations, and Step 150 and Step 152 are also single operations.

  Next, another modification of the present invention will be described. Another modified example of the present invention relates to a communication system including an access control device and a plurality of terminal devices, as in the embodiments and modified examples of the present invention. Moreover, another modification uses a 1st type | mold radio | wireless communications system and a 2nd type | mold radio | wireless communications system similarly to the modification of this invention. However, the section in which the first type wireless communication system and the second type wireless communication system are to be used in another modified example is different from the modified example. In another modification, the first type wireless communication system is used between the first type terminal apparatus and the first type access control apparatus and also in the section from the first type access control apparatus to the second type terminal apparatus. Is done. On the other hand, the type 2 wireless communication system is used in the section from the type 2 terminal device to the type 2 access control device.

  FIG. 13 shows a configuration of a communication system 100 according to another modification of the present invention. Similar to FIG. 10, the communication system 100 includes a first type access control apparatus 102, a second type access control apparatus 104, a first type terminal apparatus 142, and a second type terminal apparatus 144. Note that a plurality of first type access control devices 102, second type access control devices 104, first type terminal devices 142, and second type terminal devices 144 may be included, but here, in order to simplify the description , One for each.

  Since the first type terminal device 142 is the same as that of FIG. 10, the description thereof is omitted here. The second type terminal device 144 is a terminal device 14 carried by a pedestrian 16 (not shown), and the second type terminal device 144 transmits data to the second type access control device 104 and also performs the first type access control. Control information from the device 102 is received. That is, control information is received by the first type wireless communication system, and data is broadcast by the second type wireless communication system. This is because the access control device 10 to be transmitted is different from the access control device 10 to be received, and the radio communication system used for transmission is different from the radio communication system used for reception. It corresponds to that.

  The type 2 access control device 104 corresponds to the type 2 wireless communication system, is a packet signal from each of the plurality of type 2 terminal devices 144, and includes position information of each type 2 terminal device 144. The received packet signal is received. The second type access control apparatus 104 generates the second combination described above by aggregating position information and the like included in the packet signal, as in the embodiment. The second type access control device 104 outputs the second combination to the first type access control device 102. The first type access control apparatus 102 corresponds to the first type wireless communication system, and performs communication by a packet signal with a plurality of first type terminal apparatuses 142 and transmits packets to a plurality of second type terminal apparatuses 144. Send a signal. That is, for the first type access control apparatus 102, the terminal device 14 that is a reception target is different from the terminal device 14 that is a transmission target. The first type access control apparatus 102 generates the first combination described above by aggregating position information and the like included in the packet signal, as in the embodiment. Further, the first type access control apparatus 102 receives the second combination from the second type access control apparatus 104.

  The first type access control apparatus 102 broadcasts the first combination and the second combination using different packet signals. Each type 1 terminal device 142 and each type 2 terminal device 144 receive the packet signal from the type 1 access control apparatus 102 in the type 1 wireless communication system. The first type terminal device 142 and the second type terminal device 144 recognize the positions of the vehicle 12 and the pedestrian 16 (not shown) based on the position information included in the packet signal.

  FIG. 14 shows the configuration of the first type access control apparatus 102. The first type access control apparatus 102 includes an antenna 150, an RF unit 152, a modem unit 154, a processing unit 156, a GPS positioning unit 158, a frame generation unit 160, and a control unit 162. The processing unit 156 includes an extraction unit 164, an aggregation unit 168, and an input unit 172. The antenna 150, the RF unit 152, the GPS positioning unit 158, the frame generation unit 160, and the extraction unit 164 are the same as those in FIG. The antenna 150, the RF unit 152, and the modem unit 154 are compatible with the first type wireless communication system and cannot receive a packet signal from the second type terminal device 144 (not shown). The second type access control apparatus 104 (not shown) is the same type as the first type access control apparatus 102 shown in FIG. 14, but has only a reception function.

  The aggregation unit 168 receives the combination of information extracted by the extraction unit 164. The aggregating unit 168 generates one combination from the position information for the first type terminal device. The generated combination corresponds to the aforementioned “first combination”. The input unit 172 has a wired network interface, and is connected to the second type access control apparatus 104 (not shown) via the wired network. The input unit 172 receives the second combination from the second type access control apparatus 104 and outputs the second combination to the aggregation unit 168.

  As a result, the aggregation unit 168 holds the first combination and the second combination. In addition, the aggregation unit 168 stores the first combination and the second combination in separate packet signals. The aggregating unit 168 assigns the packet signal storing the first combination to the control slot arranged at the head of the frame. In addition, the aggregation unit 168 assigns a packet signal storing the second combination to the control slot arranged second in the frame. The modem unit 154 and the RF unit 152 broadcast-transmit the packet signal storing the first combination from the antenna 150 in the first control slot. In addition, the modem unit 154 and the processing unit 156 broadcast the packet signal storing the second combination from the antenna 150 in the second control slot. The destination of the control information is the first type terminal device 142 and the second type terminal device 144.

  The operation of the communication system 100 configured as above will be described. FIG. 15 is a sequence diagram illustrating a packet signal notification procedure in the communication system 100. The first type 2 terminal device 144a broadcasts a packet signal including data in the type 2 wireless communication system (S170). The second type 2 terminal apparatus 144b broadcasts a packet signal including data in the type 2 wireless communication system (S172). The first type 1 terminal apparatus 142a broadcasts a packet signal including data in the first type wireless communication system (S174). The second type 1 terminal apparatus 142b broadcasts a packet signal including data in the type 1 wireless communication system (S176). The second type access control device 104 receives the packet signals from the first second type terminal device 144a and the second second type terminal device 144b, aggregates the positional information and the like as the second combination, and sets the second combination to the second type. The type 1 access control apparatus 102 is notified (S178).

  The first type access control apparatus 102 receives the packet signals from the first first type terminal apparatus 142a and the second first type terminal apparatus 142b, aggregates the positional information and the like as the first combination, and also performs the second type access. The second combination from the control device 104 is received. As a result, the first type access control apparatus 102 aggregates position information and the like into the first combination and the second combination (S180). The first type access control apparatus 102 notifies the first combination and the second combination by packet signals (S182, S184, S186, S188). Here, steps 182 to 188 are a single operation.

  According to the embodiment of the present invention, the packet signals from the access control apparatus to the terminal apparatus are aggregated in a predetermined slot, so that an increase in the collision probability of packet signals can be suppressed even if the number of radio apparatuses increases. Further, since the packet signals from the access control apparatus to the terminal apparatus are aggregated in a predetermined slot, the position information of the other terminal apparatuses can be acquired if the packet signals from the access control apparatus are received. Further, since it is only necessary to receive a packet signal from the access control apparatus, the position information of the other terminal apparatus can be acquired without receiving a packet signal from the other terminal apparatus. In addition, even if no packet signal is received from another terminal device, the position information of the other terminal device is acquired, so that the acquisition probability of the position information can be improved.

  In addition, since the packet signal including the first combination and the packet signal including the second combination are separately notified, the vehicle position and the pedestrian position can be efficiently recognized. In addition, since the packet signal including the first combination and the packet signal including the second combination are separately notified, if the second type terminal device receives only the first combination, the presence of the vehicle The position can be recognized. Further, since the second type terminal device only needs to receive the first combination, the power consumption can be reduced. In addition, since the type 2 terminal device does not notify the packet signal when another type 2 terminal device exists, the increase in traffic can be suppressed. Further, since the type 2 terminal device does not notify the packet signal when another type 2 terminal device exists, the power consumption can be suppressed.

  Moreover, since another radio | wireless communications system is used with respect to a 1st type terminal device and a 2nd type terminal device, even when a 2nd type terminal device increases, the influence which it has on a 1st type terminal device can be reduced. In addition, since another wireless communication system is used for the line from the second type terminal device to the second type access control device and the first type access control device, even if the number of second type terminal devices increases, The influence on the first type terminal device can be reduced.

  Since data is reported in the slot generated according to the control information from the access control device, synchronization between a plurality of terminal devices can be established. In addition, since synchronization between a plurality of terminal devices is established, the data collision probability can be reduced. In addition, since the data is notified in the slot, it is possible to reduce the occurrence of a situation in which a part of a plurality of data overlaps and collides. Further, since data is broadcast in the slot, the frame utilization efficiency can be improved. Also, since the empty slot is estimated and any one of the empty slots is selected, the collision probability of the packet signal can be reduced even when the traffic is increased. Moreover, since the empty slot is estimated based on the result of carrier sense, it is possible to estimate the empty slot according to the situation around the terminal device.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

  In another modification of the present invention, the frame generator 160 defines a frame formed by a plurality of slots. However, the present invention is not limited to this. For example, the frame generation unit 160 may provide periods other than a plurality of slots in the frame. Specifically, a plurality of slots may be arranged in a partial period of the frame, and CSMA / CA may be performed between the plurality of terminal apparatuses 14 in the remaining period. At this time, the access control apparatus does not detect an empty slot or a collision slot during the CSMA / CA period. According to this modification, since the terminal device 14 can select communication by slot and communication by CSMA / CA, the degree of freedom of communication can be improved. That is, the frame only needs to include at least a plurality of slots.

  In the modification of the present invention or another modification, the control information notified from the access control apparatus 10 and the data notified from one terminal apparatus 14 are allocated to one slot. However, the present invention is not limited to this. For example, control information and data may be assigned to two or more slots. According to this modification, the communication speed of control information and data can be improved.

  In the embodiment of the present invention, the processing unit 156 classifies the position information about the plurality of terminal devices 14 into the first combination and the second combination. However, the present invention is not limited to this. For example, the processing unit 156 may aggregate the position information and store the packet information in the packet signal without performing classification. According to this modification, the process of the access control device 10 can be simplified.

  10 access control device, 14 terminal device, 50 antenna, 52 RF unit, 54 modulation / demodulation unit, 56 processing unit, 58 control unit, 60 timing specifying unit, 62 acquisition unit, 64 generation unit, 66 control information extraction unit, 68 slot determination Unit, 70 notification unit, 72 reception unit, 74 instruction unit, 100 communication system, 150 antenna, 152 RF unit, 154 modulation / demodulation unit, 156 processing unit, 158 GPS positioning unit, 160 frame generation unit, 162 control unit, 164 extraction unit , 166 classification unit, 168 aggregation unit.

Claims (4)

A receiving unit that receives a packet signal from each of the plurality of terminal devices in the first period;
An aggregating unit for aggregating position information included in each packet signal received by the receiving unit;
A notification unit that notifies the packet signal including the position information aggregated in the aggregation unit in a second period different from the first period;
The notification source of the plurality of packet signals received by the receiving unit is a mixture of a first type terminal device mounted on a vehicle and a second type terminal device carried by a pedestrian. Access control device. The aggregation unit separately collects position information about the first type terminal device and position information about the second type terminal device,
The notification unit separately notifies the packet signal in which the position information about the first type terminal device is aggregated and the packet signal in which the position information about the second type terminal device is aggregated in the second period. The access control apparatus according to claim 1. An acquisition unit for acquiring position information;
A notification unit for reporting in a first period a packet signal including the position information acquired in the acquisition unit;
In the second period different from the first period, the access control apparatus receives the packet signal notified by the notification unit and also receives the packet signal from another terminal apparatus. A receiving unit for receiving a packet signal including position information aggregated in the access control device;
A processing unit for processing the packet signal received in the receiving unit,
The processor is
An extraction unit that extracts a plurality of pieces of position information included in the packet signal received by the reception unit;
An instruction unit that, when position information within a predetermined range from position information acquired by the acquisition unit is present in the plurality of position information extracted by the extraction unit, causes the notification unit to stop reporting a packet signal; A terminal device comprising the terminal device. A plurality of first type terminal devices corresponding to the first wireless communication system;
A plurality of second type terminal devices corresponding to a second wireless communication system different from the first wireless communication system;
A first type access control device that receives a packet signal from each of the plurality of first type terminal devices and includes position information of each first type terminal device;
A second type access control device that receives a packet signal from each of the plurality of second type terminal devices and that includes position information of each second type terminal device;
The first type access control device notifies the packet signal of an aggregation result of the position information included in each packet signal received by the second type access control device,
The second type access control device notifies the aggregation result of the location information included in each packet signal received by the first type access control device by a packet signal,
The plurality of first type terminal devices receive packet signals from the first type access control device,
The plurality of second type terminal apparatuses receive a packet signal from the second type access control apparatus.

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