JP5482502B2 - PROCESSING DEVICE, PROCESS STARTING METHOD, CONTROL PROGRAM, AND RECORDING MEDIUM - Google Patents

Description

  The present invention relates to a processing device used in a communication (VICS communication: Vehicle Information Communication System) system when a mobile station moves at high speed, an ETC system (Electronic Toll Collection System) that handles toll collection, etc., and a process start The present invention relates to a method, a control program, and a recording medium, and more particularly to a processing device, a processing start method, a control program, and a recording medium that start processing in consideration of a delay time that occurs in the communication.

  An ETC system that collects tolls for toll roads by exchanging necessary messages between a vehicle-mounted device mounted on an automobile and a roadside radio device at a toll gate using wireless communication is becoming widespread. As for the ETC system, for example, Patent Document 1 discloses the technology. Moreover, as a standard regarding an ETC system, there exists a narrow band communication (DSRC: Dedicated Short-Range Communication) system ARIB STD-T75 (nonpatent literature 1), for example.

  FIG. 9 shows a schematic configuration diagram of the ETC system. In FIG. 9, the ETC system is installed on the roadside with mobile devices (mobile stations) 810, 820, etc. mounted on a vehicle, and detects that the vehicle-mounted device has entered the communication range and transmits and receives messages. A device (base station) 910. When the on-vehicle devices 810 and 820 and the roadside wireless device 910 transmit and receive various messages, the roadside wireless device 910 collects toll road charges from the on-vehicle devices 810 and 820.

  The roadside apparatus 910 includes an antenna unit 920, an optical fiber unit 930, and a control unit 940. The antenna unit 920 performs wireless communication with the vehicle-mounted devices 810 and 820. The optical fiber unit 930 transmits various messages between the antenna unit 920 and the control unit 940. The optical fiber unit 930 transmits various messages by multiplexing slots in a communication frame using different frequencies in the uplink channel and the downlink channel (full duplex communication). The control unit 940 performs various controls. For example, the control unit 940 generates a communication frame to be transmitted to the vehicle-mounted device, and transmits the communication frame to the plurality of vehicle-mounted devices 810, 820, ... via the downlink channel. Further, the control unit 940 extracts and processes various messages from the communication frames received from the vehicle-mounted devices 810, 820, ... via the uplink channel.

  Next, a communication frame transmitted and received between the roadside apparatus 910 and the vehicle-mounted devices 810 and 820 will be briefly described. FIG. 10 shows an example of a communication frame. The communication frame in FIG. 10 is based on synchronous adaptive slotted aloha communication control. The communication control of the synchronous adaptive slotted aloha system is a communication control system applied to bidirectional communication of full duplex communication within a short time of point-to-point. The communication frame includes a plurality of slots having the same time length. Each slot is used in both downlink and uplink directions. In the downlink, the roadside wireless device 910 includes the message in the slot, and in the uplink, the vehicle-mounted devices 810 and 820 include the message in the slot. The functions of the slots of the communication frame shown in FIG. 10 are summarized in FIG.

  In FIG. 10, an FCMS (Frame Control Message Slot) including slot allocation information, frame control information, and the like is arranged at the head of the communication frame. When the vehicle-mounted devices 810 and 820 receive an MDS (Message Data Slot) designated by FCMS, they return an ACK channel (hereinafter referred to as ACKC) using the same slot. Further, the vehicle-mounted devices 810 and 820 transmit various messages to the roadside apparatus 910 using slots designated by the roadside apparatus 910 using FCMS.

  For example, the vehicle-mounted device 810 receives MDC (Message Data Channels) (1) by the second slot (MDS (1)) next to FCMS (1), and receives ACKC in the same slot (second slot). ) To reply (II). Further, the vehicle-mounted device 810 transmits MDC (3) to the roadside apparatus 910 using the fourth slot (MDS (3)) of the uplink channel (V). When the roadside apparatus 910 receives the MDC (3) using the fourth slot, the roadside apparatus 910 returns an ACKC indicating that it has been received normally using the same slot (fourth slot) (VI).

  Similarly, the vehicle-mounted device 820 receives MDC (2) (III), and returns ACKC (IV). Furthermore, the vehicle-mounted device 820 transmits MDC (4) to the roadside apparatus 910 using the fifth slot of the uplink channel (VII), and an ACCC is returned from the roadside apparatus 910 (VIII).

  Note that the on-vehicle devices 810 and 820 return an ACKC including an ACK signal when the MDC can be normally received. On the other hand, if the MDC cannot be received normally, the NACK signal is returned in the ACCC. If MDS is not received, ACKC itself is not returned.

  On the other hand, the control unit 940 of the roadside apparatus 910 outputs an MDC to the vehicle-mounted device and then receives and processes an ACKC for the MDC from the vehicle-mounted device. When the NACK signal is included as a result of processing the ACKC, the control unit 940 outputs the MDC again.

  Here, after outputting the MDC, a predetermined delay time is generated until an ACCC is returned. The delay time is mainly the time required for processing the communication frame and the time required for transmission of the optical fiber unit 930. The time required for processing the communication frame can be calculated from the design value of the device used or the vehicle-mounted device. On the other hand, the transmission time by the optical fiber unit 930 depends on the length of the optical fiber unit 930. The delay time resulting from the transmission of the optical fiber unit 930 is disclosed in Patent Document 2, for example. In the roadside apparatus 910, a delay time calculated based on the design values of the apparatus and the vehicle-mounted device, the length of the optical fiber unit 930, and the like is registered in advance. The roadside apparatus 910 starts the ACCC process when the set delay time has elapsed after outputting the MDC.

JP 2000-298746 A JP 2002-359629 A

Narrowband Communication (DSRC) System ARIB STD-T75

  FIG. 12 shows an example of a block diagram of the roadside apparatus 910. In the delay counter 941 of the roadside apparatus 910, a delay time calculated based on the design values of the apparatus and the vehicle-mounted device and the length of the optical fiber unit 930 is registered in advance. After the signal processing circuit 943 generates and outputs a communication frame, the delay counter 941 counts a preset delay time and outputs it to the retiming circuit 942. The retiming circuit 942 determines the retiming position of the communication frame received from the vehicle-mounted device based on the delay time counted by the delay counter 941 and outputs it to the signal processing circuit 943. The signal processing circuit 943 recognizes the retiming position determined by the retiming circuit 942 as the head of ACKC received from the vehicle-mounted device, and starts ACKC processing.

  The roadside apparatus 910 described above needs to set in advance the delay time calculated based on the design values of the apparatus and the vehicle-mounted device, the length of the optical fiber unit 930, and the like in the delay counter 941. In this case, it takes time to measure the length of the optical fiber portion 930, and the number of field setting items increases. Furthermore, if an incorrect delay time is set in the delay counter 941, a communication error occurs between the roadside apparatus 910 and the vehicle-mounted devices 810 and 820, and problems such as inability to charge correctly occur.

  The present invention has been made in view of the above-described problem, and starts the ACCC process by appropriately retiming the returned communication frame without calculating the delay time in advance and setting it in the roadside apparatus. It is an object of the present invention to provide a processing device, a processing start method, a control program, and a recording medium that can be used.

In order to achieve the above object, the processing device according to the present invention outputs a first communication frame to a communication partner and receives a second communication frame including a response result for the first communication frame from the communication partner. Generating a pulse when a predetermined signal is detected from the second communication frame, writing the pulse into the buffer, a first communication frame, and a second communication frame. And processing means for reading out pulses from the buffer means. Here, the processing means sets, as a predetermined period, a period longer than a period obtained by adding a delay time to the reception estimation time of the response result and shorter than a period until a new first communication frame is generated, and is read If the pulse is included in a predetermined period, the read position of the pulse is determined as the processing start position of the response result.

In order to achieve the above object, a process start method according to the present invention is a process start method using a buffer means in which a pulse is written, and after generating and outputting a first communication frame, the first communication frame When the second communication frame including the response result is received and a predetermined signal is detected from the second communication frame, a pulse is generated and written to the buffer, and a delay time is added to the estimated reception time of the response result When a predetermined period is set as a predetermined period that is longer than the predetermined period and shorter than a period until a new first communication frame is generated, and the read pulse is included in the set predetermined period, the reading of the pulse is performed. The position is recognized as the processing start position of the response result.

In order to achieve the above object, a control program according to the present invention is a control program that can be executed by a computer of an apparatus having a buffer means in which pulses are written, and after generating and outputting a first communication frame, A function of receiving a second communication frame including a response result for one communication frame, a function of generating a pulse and writing to a buffer means when a predetermined signal is detected from the second communication frame, and a response result Is set as a predetermined period that is longer than the period obtained by adding the delay time to the estimated reception time and shorter than the period until a new first communication frame is generated, and within the predetermined period set by the read pulse Included in the apparatus, the function of recognizing the read position of the pulse as the processing start position of the response result is executed by the computer of the apparatus.

In order to achieve the above object, a recording medium according to the present invention generates a first communication frame and outputs it to a computer of a device having a buffer means to which pulses are written, and then a response result for the first communication frame. A procedure for receiving a second communication frame including a signal, a procedure for generating a pulse when a predetermined signal is detected from the second communication frame and writing it to the buffer means, and a delay time in the estimated reception time of the response result. If a period longer than the added period and shorter than a period until a new first communication frame is generated is set as the predetermined period, and the read pulse is included in the set predetermined period, This is a recording medium readable by the computer of the apparatus, in which a control program for executing a procedure for recognizing a reading position as a processing start position of a response result is recorded.

  With the above-described configuration, it is possible to appropriately retiming the returned second communication frame and start processing the response result without calculating delay time in advance and setting it in the processing device. A processing device, a processing start method, a control program, and a recording medium can be provided.

It is an example of the block diagram of the processing apparatus 1 which concerns on the 1st Embodiment of this invention. It is an example of the block diagram of the roadside apparatus 10 which concerns on the 2nd Embodiment of this invention. It is an example of the frame structure of the communication frame which the roadside apparatus 10 which concerns on the 2nd Embodiment of this invention handles. It is an example of the frame structure of the communication frame (uplink channel) which concerns on the 2nd Embodiment of this invention. It is an example of the block diagram of the roadside apparatus 20 which concerns on the 3rd Embodiment of this invention. It is an example of the circuit diagram of the pulse generation circuit 24 which concerns on the 3rd Embodiment of this invention. It is an example of the structure of the communication frame which the roadside apparatus 20 which concerns on the 3rd Embodiment of this invention handles. It is an example of the structure of the slot which the roadside apparatus 20 which concerns on the 3rd Embodiment of this invention handles. It is a schematic block diagram of the ETC system of related technology. It is an example of the structure of the communication frame which the roadside apparatus 910 of related technology handles. 11 is a list of slot functions used in the communication frame shown in FIG. 10. It is an example of the block diagram of the roadside apparatus 910 of related technology.

(First embodiment)
A first embodiment according to the present invention will be described. FIG. 1 shows an example of a block diagram of a processing apparatus according to this embodiment. In FIG. 1, the processing apparatus 1 includes a communication unit 2, a pulse generation unit 3, a buffer unit 4, and a processing unit 5.

  The communication means 2 outputs the first communication frame to the communication partner and receives the second communication frame including the response result for the first communication frame from the communication partner.

  The pulse generation unit 3 generates a pulse when a predetermined signal is detected from the second communication frame received by the communication unit 2 and writes the generated pulse in the buffer unit 4.

  A pulse generated by the pulse generation unit 3 is written in the buffer unit 4. The written pulse is read from the processing means 5.

  The processing unit 5 generates a first communication frame and outputs it to the communication unit 2. Further, the second communication frame including the response result received from the communication partner is received from the communication unit 2. Further, the processing means 5 reads the pulse from the buffer means 4. Then, when a pulse is read from the buffer means 4 within a predetermined period, the processing means 5 uses the position (timing) corresponding to the position (timing) from which the pulse is read as the processing start position of the response result. judge.

  Here, the processing means 5 remembers the time related to the generation of the first communication frame, and sets a period during which a response result is expected to be returned based on the time related to the generation of the first communication frame. Period. Then, when a pulse is read out within the predetermined period, the processing unit 5 sets a position corresponding to the position of the pulse as a processing start position of the response result.

  With the above configuration, the processing means 5 appropriately performs retiming processing on the second communication frame received from the communication partner without knowing the time (delay time) required for transmission / reception of information with the communication partner. Thus, processing of the response result can be started. That is, the processing device 1 according to the present embodiment appropriately performs retiming processing on the second communication frame transmitted from the communication partner without setting a delay time in the processing device 1 in advance, and processes the response result. Can start.

(Second Embodiment)
A second embodiment according to the present invention will be described. In the present embodiment, as a communication partner, a vehicle-mounted device mounted on an automobile (moving body) is installed as a processing device on the roadside, and a roadside wireless device that performs wireless communication with the vehicle-mounted device is applied.

  FIG. 2 shows an example of a block diagram of the roadside apparatus according to the present embodiment. In FIG. 2, the roadside apparatus 10 includes an antenna unit 11, an optical fiber unit 12, and a control unit 13. In the present embodiment, the control unit 13 includes a pulse generation circuit 14, a FIFO (First-In / First-out) memory 15, and a signal processing circuit 16.

  The antenna unit 11 performs wireless communication with a vehicle-mounted device mounted on a vehicle (not shown). In the present embodiment, the antenna unit 11 transmits the communication frame generated by the control unit 13 to the vehicle-mounted device, and outputs the communication frame received from the vehicle-mounted device to the control unit 13 via the optical fiber unit 12.

  The optical fiber unit 12 transmits a downlink communication frame from the control unit 13 to the antenna unit 11 as an optical signal. The optical fiber unit 12 transmits an uplink communication frame from the antenna unit 11 to the control unit 13 as an optical signal.

  The control unit 13 controls each unit and each circuit of the roadside apparatus 10. In addition, various messages are exchanged with the vehicle-mounted device using a communication frame.

  The pulse generation circuit 14 of the control unit 13 is arranged at the subsequent stage of the optical fiber unit 12 on the uplink channel side of the control unit 13. The pulse generation circuit 14 returns from the vehicle-mounted device via the optical fiber unit 12 and writes the communication frame in the FIFO memory 15 together with the write clock. When the pulse generation circuit 14 detects a predetermined signal from the input communication frame, the pulse generation circuit 14 generates a pulse and writes the generated pulse in the FIFO memory 15 together with the communication frame. The generation of the pulse will be described later.

  In the FIFO memory 15, the communication frame received from the vehicle-mounted device and the pulse generated by the pulse generation circuit 14 are written together with the write clock. The communication frame written in the FIFO memory 15 is read from the signal processing circuit 16 using a read clock.

  The signal processing circuit 16 generates a communication frame and outputs it to the vehicle-mounted device via the optical fiber unit 12 and the antenna unit 11. Further, the signal processing circuit 16 reads the communication frame from the FIFO memory 15 using the read clock. Further, when a pulse is read out within a predetermined period, the signal processing circuit 16 recognizes the timing at which the pulse is output as the head of the ACKC, and starts the ACKC processing.

  Here, the downlink communication frame corresponds to the first communication frame of the claims, the uplink communication frame corresponds to the second communication frame of the claims, and ACKC corresponds to the response result of the claims. Further, the antenna unit 11 corresponds to a communication unit, the optical fiber unit 12 corresponds to a transmission unit, the FIFO 15 corresponds to a buffer unit, and the signal processing circuit 16 corresponds to a processing unit.

  Next, communication frames transmitted and received between the roadside apparatus 10 and the vehicle-mounted device will be described. FIG. 3 shows an example of a downlink communication frame, and FIG. 4 shows an example of an uplink communication frame. In this embodiment, one frame is composed of three slots.

  In FIG. 3, the first slot of the downlink communication frame includes FCMC. The FCMC includes frame information such as the type of subsequent slot and the number of subsequent slots included in the communication frame, and a preamble (PR) and a unique word 1 (UW1) are arranged at the head of the FCMC. The second slot and the third slot following the first slot include MDC1 and MDC2 used for transmitting various messages from the roadside apparatus 10. A preamble (PR) and a unique word 2 (UW2) are arranged at the head of the MDC.

  The vehicle-mounted device exchanges various messages with the roadside apparatus 10 using the slot allocated from the roadside apparatus 10 based on the frame information included in the FCMC. When the on-vehicle device receives the MDC in the assigned slot, it returns an ACKC. In FIG. 3, ACKC is indicated by a dotted line. Preamble (PR) and unique word 2 (UW2) are arranged at the head of ACKC.

  On the other hand, in FIG. 4, the uplink communication frame includes ACTC which is an MDC response and ACTC (Activation Channels) used for connection to the roadside apparatus 10. In FIG. 4, MDC1 and MDC2 are indicated by dotted lines. Here, the preamble (PR) and the unique word 2 (UW2) are arranged at the head of the ACCC and ACTC.

  In this embodiment, when the pulse generation circuit 14 detects the unique word 2 (UW2) following the preamble (PR), it generates a pulse and writes it in the FIFO memory 15 together with the communication frame. FIG. 4 also shows the pulses generated by the pulse generation circuit 14. In the example of FIG. 4, the pulse generation circuit 14 generates three pulses 17a to 17c and writes them in the FIFO memory 15 together with the communication frame. “PR + UW2” is one aspect of the “predetermined signal” in the claims.

  On the other hand, the signal processing circuit 16 reads the communication frame from the FIFO memory 15 using the read clock. In the example of FIG. 4, the signal processing circuit 16 reads out three pulses 17 a to 17 c from the FIFO memory 15. Here, since the signal processing circuit 16 remembers the output timing of the MDC, it can extract only the pulse at the subsequent stage of the MDC. The signal processing circuit 16 extracts the pulses 17a and 17c as the subsequent pulse of the MDC, recognizes the timing when the pulses 17a and 17c are read out as the head of the ACKC, and starts the ACKC processing.

  As described above, the roadside apparatus 10 according to the present embodiment once writes the communication frame returned from the radio apparatus in the FIFO memory 15, and the signal processing circuit 16 reads the communication frame from the FIFO memory 15. Further, when the unique word 2 (UW2) is detected following the preamble (PR), the pulse generation circuit 14 generates a pulse and writes it in the FIFO memory 15 together with the communication frame. The signal processing circuit 16 extracts a pulse at the latter stage of the MDC and starts ACKC processing.

  Since the delay time from the MDC output until the ACCC is returned is absorbed by the FIFO memory 15, it is not necessary to calculate the delay time and register it in the roadside apparatus 10 in advance. Therefore, the roadside apparatus 10 according to the present embodiment appropriately performs retiming processing on the communication frame returned from the vehicle-mounted device without calculating the delay time and setting it in the roadside apparatus 10, and performs the ACCC process. Can start.

  In this embodiment, the pulse and the communication frame are written in the FIFO memory 15, but the present invention is not limited to this. For example, only the pulse can be written in the FIFO memory 15, and the communication frame can be directly input to the signal processing circuit 16 without being written in the FIFO memory 15. In this case, the signal processing circuit 16 starts ACKC processing in the input communication frame when the subsequent pulse of the MDC is read.

  In this embodiment, the pulse generation circuit 14 generates a pulse when the unique word 2 (UW2) is detected following the preamble (PR). However, the unique words 2 and 3 are generated following the preamble (PR). A pulse may be generated when (UW2, UW3) is detected. When extracting a pulse generated by detecting the unique word 3, for example, the signal processing circuit 16 sets the receivable period of WCNC (Wireless Call Number Channels) shown in FIG. Set as.

(Third embodiment)
A third embodiment will be described. In the present embodiment, a roadside wireless device installed on the roadside in the ETC system is used as the processing device, and an in-vehicle device mounted on an automobile (moving body) is applied as the wireless device.

  FIG. 5 shows an example of a block diagram of the roadside apparatus according to the present embodiment. In FIG. 5, the roadside apparatus 20 includes an antenna unit 21, optical fiber units 22 a and 22 b, and a control unit 23. The control unit 23 includes a pulse generation circuit 24, a FIFO memory 25, a signal processing circuit 26, parallel / serial conversion circuits 28a and 28b, and E / O conversion circuits 29a and 29b.

  The antenna unit 21 transmits the communication frame generated by the control unit 23 to the vehicle-mounted device, and outputs the communication frame received from the vehicle-mounted device to the control unit 23 via the optical fiber unit 22b.

  The optical fiber units 22a and 22b transmit a communication frame as an optical signal between the antenna unit 21 and the control unit 23.

  The control unit 23 controls each unit and each circuit of the roadside apparatus 20. In addition, various messages are exchanged with the vehicle-mounted device using a communication frame.

  The control unit 23 will be described in detail. The signal processing circuit 26 determines to which on-vehicle device a plurality of slots in the communication frame are allocated, and generates 8-bit signal data and control data as the communication frame. The generated signal data and control data are output to the parallel / serial conversion circuit 28a.

  The parallel / serial conversion circuit 28a develops the received signal data and control data in parallel, further serializes them to 1 bit, and outputs them to the E / O conversion circuit 29a. The E / O conversion circuit 29a converts the 1-bit electrical signal received from the parallel / serial conversion circuit 28a into an optical signal and outputs the optical signal to the optical fiber portion 22a.

  On the other hand, the communication frame received from the vehicle-mounted device via the optical fiber portion 22b is input to the E / O conversion circuit 29b. The E / O conversion circuit 29b converts the optical signal received from the vehicle-mounted device into a 1-bit electrical signal and outputs it to the parallel / serial conversion circuit 28b. The parallel / serial conversion circuit 28 b separates the 1-bit electrical signal received from the E / O conversion circuit 29 b into 8-bit signal data and control data, and outputs the signal data to the pulse generation circuit 24.

  The pulse generation circuit 24 writes the parallelized signal data and control data to the FIFO memory 25 using a write clock. Further, the pulse generation circuit 24 generates a pulse and writes it in the FIFO memory 25 when the parallelized signal data and control data are in a predetermined arrangement.

In the present embodiment, the pulse generation circuit 24 generates a pulse when the following arrangement is detected.
PR (16 Bit) “10101010110101010”
UW2 (16 Bit) “0100101100111110”

In the present embodiment, a predetermined arrangement is detected from the parallelized signal data, but it can also be detected from a communication frame that has been serialized. When the serialized communication frame is used, the pulse generation circuit 24 generates a pulse when the following arrangement is detected.
PR + UW2 (32 bits) “10101010101010100100101100111110”

  Returning to the description of the control unit 23. In the FIFO memory 25, signal data, control data, and pulses are written. In the present embodiment, signal data and control data are written in the FIFO memory 25 without being distinguished. Further, the signal data, control data, and pulse written in the FIFO memory 25 are read from the signal processing circuit 26 using a read clock.

  In parallel with the generation of the communication frame, the signal processing circuit 26 reads signal data, control data, and pulses from the FIFO memory 25 using a read clock. Here, the read clock is generated independently of the write clock used by the pulse generation circuit 24, and only the phase is different from the write clock. Since the signal processing circuit 26 knows the generation time of the MDC, it can extract only the pulses read out at the subsequent timing of the MDC out of the pulses read out from the FIFO memory 25. When a pulse is read from the FIFO memory 25 at a later stage of the MDC, the signal processing circuit 26 starts processing for ACKC using the read pulse as the starting point of ACKC.

  In this embodiment, the entire communication frame (signal data and control data) is written in the FIFO memory 25, but the present invention is not limited to this. Only the necessary signal data (for example, ACKC) can be written in the FIFO memory 25 by outputting a write clock only when there is signal data. FIG. 6 shows an example of a circuit diagram of the pulse generation circuit 24 when only necessary signal data is written in the FIFO memory 25. In FIG. 6, the pulse generation circuit 24 detects a continuous fixed BIT string of PR and UW by taking an exclusive OR with signal data. Then, a pulse is generated when the BIT strings coincide with each other and is written in the FIFO memory 25 together with the signal data.

  Further, it is not always necessary to write the entire ACKC in the FIFO memory 25. For example, only the first few bytes of ACKC data can be written into the FIFO memory 25. In this case, the first several bytes of the ACKC written in the FIFO memory 25 are pre-read together with the pulse, so that the data part of the ACKC is directly input to the signal processing circuit 26 without being written in the FIFO memory 25. To be processed.

  Next, the delay time from when the MDC is output to when the ACCC is received will be described. In FIG. 7, an example of a structure of the communication frame transmitted / received between the roadside apparatus 20 and onboard equipment is shown. The communication frame in FIG. 7 has a three-slot configuration and a frame length of 2.34375 msec. The communication frame is applied to full-duplex two-way communication. One slot is 100 bytes (0.78125 msec), and the transmission speed is 1,024 kbps.

  In FIG. 7, the first slot includes FCMC. The in-vehicle device performs wireless communication using the MDS assigned from the roadside apparatus 20 based on the frame information included in the FCMC.

  The second slot and the third slot following the first slot include MDC1 and MDC2 output from the roadside apparatus 20 and ACKC output as a response from the vehicle-mounted device.

  Here, in FIG. 7, a predetermined guard timer is set between each channel in consideration of the processing time of each circuit and the transmission time required for optical transmission. For example, between the start of the first slot and the output of FCMC, 218.75 μsec is set as guard timer t0, 93.75 μsec is set as guard timer t2 between FCMC and MDC, and between MDC and ACCC. 85.94 μsec is set as the guard timer t3, and 70.31 μsec is set as the guard timer t4 between the ACCC and the next slot.

  As already described, the ACCC from the vehicle-mounted device for the MDC output from the roadside apparatus 20 cannot be returned across the slots. That is, the ACKC returned from the vehicle-mounted device must be returned before the start of the next slot after the output of the MDC. That is, the ACKC returned from the vehicle-mounted device needs to be processed by the signal processing circuit 26 before the guard timer t4 elapses.

  The time required to receive ACKC will be described with reference to FIGS. As described above, the MDC generated by the signal processing circuit 26 is subjected to predetermined processing by the parallel / serial conversion circuit 28a and the E / O conversion circuit 29a, and then passes through the optical fiber portion 22a and the antenna portion 21. Output to OBE.

  Here, after the MDC is generated by the signal processing circuit 26, the total time taken until it is received by the vehicle-mounted device is described as a delay time (1) ((1) in FIG. 8). The delay time (1) is the total of the time required for various processing of the MDC and the transmission time in the optical fiber portion 22a. As the time required for various processes of the MDC, a fixed value calculated from a design value or the like of the roadside apparatus 20 can be used. In the present embodiment, the time required for various MDC processes is 2 μsec. On the other hand, the transmission time in the optical fiber portion 22a is proportional to the length of the optical fiber portion 22a. For example, when the length of the optical fiber portion 22a is 2000 m, it takes about 5 nsec for the MDC to travel 1 m through the optical fiber portion 22a. Therefore, transmission time = 2000 m × 5 nsec = 10000 nsec (10 μsec). Therefore, the delay time (1) = 10 μsec + 2 μsec = 12 μsec.

  Next, the vehicle-mounted device that has received the MDS from the roadside apparatus 20 returns an ACCC using the same slot. The in-vehicle device sends back an Ack signal in the case of successfully receiving the MDC, and returns a Nack signal in the case of being unable to receive the MDC normally. The time from when the vehicle-mounted device receives the MDC, generates an ACCC, and returns it to the antenna unit 21 is described as a delay time (2) ((2) in FIG. 8). The delay time (2) is the total time such as the time for receiving and processing the MDC and the time required for generating the ACKC, etc. The performance of the vehicle-mounted device, the communication state between the vehicle-mounted device and the antenna unit 21, the installation state of the vehicle-mounted device, Depends on. In the present embodiment, delay time (2) = 100 μsec.

  Further, the ACCC received from the vehicle-mounted device is input to the E / O conversion circuit 29b via the antenna unit 21 and the optical fiber unit 22b. Then, after predetermined processing is performed by the E / O conversion circuit 29 b and the parallel / serial conversion circuit 28 b, the data is written into the FIFO memory 25 via the pulse generation circuit 24. The total time taken from when the ACKC is output from the vehicle-mounted device to when it is written to the FIFO memory 25 is referred to as a delay time (3) ((3) in FIG. 8). The delay time (3) is substantially the same as the delay time (1), and in this embodiment, the delay time (3) = 12 μsec.

  Here, the total 124 μsec (= 12 μsec + 100 μsec + 12 μsec) of the delay times (1), (2), and (3) needs to be smaller than the total time of t3 (11 bytes) and t4 (9 bytes). Since the transmission speed is 1,024 kbps, t3 + t4 = 11 bytes + 9 bytes = (20 × 8) bits / (1.024 kbps) = 156.25 μsec, and the above delay time (1) (2) (3) = 124 μsec is This condition is satisfied.

  In the present embodiment, the delay times (1), (2), and (3) described above are obtained by temporarily writing the communication frame received from the vehicle-mounted device into the FIFO memory 25, and then reading out from the FIFO memory 25 again by the signal processing circuit 26. It is absorbed by the memory 25.

  As described above, in the roadside apparatus 20 according to the present embodiment, the pulse generation circuit 24 generates a pulse when PR and UW2 are detected, and writes the pulse in the FIFO memory 25 together with the communication frame. Then, after the MDC is generated, the signal processing circuit 26, when a pulse is read from the FIFO memory 25 at a timing near the time when the guard timer t3 elapses (corresponding to a predetermined period of the claims), The processing related to ACCC is started. That is, the total time (delay time (1) (2) (3)) of the time required for signal processing and the transmission time of the optical fiber portions 22a and 22b is absorbed by the FIFO memory 25.

  Therefore, the roadside apparatus 20 according to the present embodiment preliminarily calculates the delay times (1), (2), and (3) calculated based on the design values of the apparatus and the vehicle-mounted device, the length of the optical fiber unit, and the like. Without being set to 20, it is possible to appropriately retiming the returned communication frame and start the ACCC process.

Here, the following advantages are obtained by using the roadside apparatus 20 according to the present embodiment. (1) The process of measuring the length of the optical fiber portion can be saved and the process can be simplified.
(2) Field adjustment items such as laying of optical fiber parts and registration of delay times are simplified.
(3) At the time of relocation of the ETC lane, the trouble of re-measurement and re-registration of the length of the optical fiber portion is saved, and the work content is simplified, the work process is shortened, and the adjustment is simplified.
(4) A communication error between the roadside apparatus and the vehicle-mounted device due to erroneous registration of the time required for signal processing and the transmission time of the optical fiber section is eliminated, and erroneous charging and system malfunction can be prevented.

DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Communication means 3 Pulse generation means 4 Buffer means 5 Processing means 10, 20 Roadside radio apparatus 11, 21 Antenna part 12, 22 Optical fiber part 13, 23 Control part 14, 24 Pulse generation circuit 15, 25 FIFO memory 16 , 26 Signal processing circuit 17a, 17b, 17c Pulse 28a, 28b Parallel / serial conversion circuit 29a, 29b E / O conversion circuit 810, 820 On-board unit 910 Roadside device 920 Antenna unit 930 Optical fiber unit 940 Control unit

Claims (10)

A communication means for outputting a first communication frame to a communication partner, and receiving a second communication frame including a response result for the first communication frame from the communication partner;
Pulse generating means for generating a pulse when a predetermined signal is detected from the second communication frame, and writing the pulse to the buffer means;
Processing means for generating the first communication frame, receiving the second communication frame, and reading the pulse from the buffer means;
With
The processing means sets and reads a predetermined period as a period longer than a period obtained by adding a delay time to the estimated reception time of the response result and shorter than a period until a new first communication frame is generated. When a pulse is included in the set predetermined period, the position of the pulse is determined as the processing start position of the response result. The first communication frame is a downlink communication frame, the second communication frame is an uplink communication frame, and the predetermined signal is a preamble (PR) and a unique word (UW). The processing apparatus according to 1. The processing apparatus according to claim 1, wherein the predetermined period is a period based on a time related to generation of the first communication frame. The first communication frame includes a message data channel (MDC), the response result is an ACK channel (ACKC) for the MDC, and the predetermined period is a time when the processing means generates the MDC. The processing apparatus of any one of Claims 1 thru | or 3 which is the period on the basis of. The pulse generation means writes the pulse to the buffer means using a predetermined write clock,
The processing means reads the pulse from the buffer means using a read clock that is different in phase only from the write clock.
The processing apparatus of any one of Claims 1 thru | or 4. The processing apparatus according to claim 1, further comprising a transmission unit configured to transmit the first communication frame and the second communication frame between the communication unit and the processing unit. The processing device according to any one of claims 1 to 6, wherein the processing device is a roadside wireless device arranged on a roadside in an ETC system. A process start method using a buffer means in which a pulse is written,
After generating and outputting a first communication frame, receiving a second communication frame including a response result for the first communication frame;
When a predetermined signal is detected from the second communication frame, a pulse is generated and written to the buffer means;
A period longer than a period obtained by adding a delay time to the estimated reception time of the response result and shorter than a period until a new first communication frame is generated is set as a predetermined period, and the read pulse is set as described above. A process start method for recognizing a read position of the pulse as a process start position of the response result when included in a predetermined period . A control program executable by a computer of a device having a buffer means to which pulses are written,
A function for receiving a second communication frame including a response result for the first communication frame after generating and outputting the first communication frame;
A function of generating a pulse and writing to the buffer means when a predetermined signal is detected from the second communication frame;
A period longer than a period obtained by adding a delay time to the estimated reception time of the response result and shorter than a period until a new first communication frame is generated is set as a predetermined period, and the read pulse is set as described above. A function of recognizing the read position of the pulse as the processing start position of the response result when included in a predetermined period ;
A control program for causing a computer of the apparatus to execute the above. In the computer of the device with buffer means to which the pulses are written,
A procedure for receiving a second communication frame including a response result for the first communication frame after generating and outputting the first communication frame;
When a predetermined signal is detected from the second communication frame, a pulse is generated and written to the buffer means;
A period longer than a period obtained by adding a delay time to the estimated reception time of the response result and shorter than a period until a new first communication frame is generated is set as a predetermined period, and the read pulse is set as described above. A procedure for recognizing a read position of the pulse as a processing start position of the response result when included in a predetermined period ;
Recorded a control program to execute
A computer-readable recording medium of the apparatus.

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