JPH0795262A - Beacon communication controlling device - Google Patents

Abstract

PURPOSE:To simplify the communication procedure and to improve the transmission efficiency by omitting messages for the end of reception and normally from the reception side at the end of transferring messages. CONSTITUTION:In the communication controlling device which sends messages of the information from a center between the beacon and a vehicle, a modem procedure part 16 divides the message into plural blocks and sends it to the beacon by the prescribed transmission system. At the reception side, when the message block is unique, the order check of the block header number is not required so that when the block header is normally accepted, it omits that the return of messages for the end of reception and normally. Thus, the communication procedure is simplified by reducing the number of messages for confirmation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road traffic information communication system, and more particularly to a road traffic information communication system between a center for forming and transmitting information by a road administrator and a beacon installed on a road and providing the information to vehicles. It relates to simplifying data communication procedures.

[0002]

2. Description of the Related Art Conventionally, VIC has been used as a technology in such a field
S (Vehicle Information and Communication System)
There is a road traffic information communication system called as below, which will be described below. FIG. 20 is a diagram showing a system configuration of VICS. The VICS shown in this figure aims to improve road traffic smoothness and safety by providing an information service that enables dynamic navigation on the in-vehicle device side. Information from road managers (congestion, accident) , Regulations, construction, etc.) are collected at the VICS center. The VICS center performs processing such as editing and recording, and further converts it into a data format suitable for each provided medium. Provided media include a beacon method, an FM multiplex broadcasting method, and a teleterminal method. The interface device informs the driver of each medium through images, sounds, etc. depending on the situation. Here, in the beacon system related to the present invention, spot communication on-road devices are installed on the road at regular intervals, and communication is performed with an on-vehicle device. The beacon method will be described below.

FIG. 21 is a diagram for explaining the outline of the VICS communication protocol. The communication between the VICS center and the beacon is connected using a public telephone line or a dedicated telephone line. As shown in the figure, communication between the VICS center and the beacon center is performed by a modem control procedure, a LAPB (asynchronous balanced mode of high level control procedure) procedure protocol,
It is connected by a three-layer wrap-around protocol of the beacon message procedure protocol. A physical connection to a telephone line is made by using a modem and CCITT V22bis modem control procedure. The link layer protocol for error control is connected by the asynchronous balanced mode (LAPB procedure: Link Access Protocol Balanced) of the high level control procedure.

FIG. 22 is a block diagram for explaining the reception control procedure in the beacon in more detail. As shown in this figure,
When the beacon receives data, the modem procedure unit 1, HD
CRC (Cyclic Redundancy Check) error check 3 after going through LC (High Level Data Link Control) procedure section 2
The error of the data is detected in step S1, and if there is no error, the process proceeds to the message procedure unit 4 and the application unit 5. If there is an error, the center is requested to retransmit the data. In this way, for the error control of this protocol when retransmitting data, the automatic repeat request (Automatic Repeat reQuest) system is used, and management is performed by the block number of data. The details of the modem procedure unit 1, the HDLC procedure unit 2, the CRC error check unit 3, the message procedure unit 4, and the application unit 5 will be described in the embodiment section. further,
A protocol unique to the beacon is provided above the LAPB procedure, and has a function of interrupting and transmitting the message currently being transmitted when an urgent message transmission request is generated during beacon message transfer. From the above, L
Double error control is performed by the APB procedure and the message procedure to realize highly reliable communication.

[0005]

However, the conventional beacon communication control device has the following problems. Figure 2
FIG. 3 is a diagram for explaining a conventional communication procedure between a VICS center and a beacon. Since the communication between the VICS center and the beacon is modem connection, HDLC connection, and beacon message transfer connection, as shown in this figure, the beacon is sent from the beacon to the center in response to the "beacon status notification request" sent from the center to the beacon. "RR", beacon status notification request is completed, and further, from the center to beacon "beacon status notification result", "beacon to center transmission" RR ", beacon status notification result complete", From the mobile station to the beacon, thus requiring multiple confirmation messages for each message transmission. Therefore, there is a problem that the complicated procedure should be further simplified in consideration of the function in each layer.

As shown in FIG. 22, if there is an error, a resend request is automatically made, which requires extra time. The problem is to reduce the number of retransmissions and improve transfer efficiency. Therefore, an object of the present invention is to provide a beacon communication control device that can simplify the procedure and improve the transfer efficiency in view of the above problems.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a communication control device for transferring information from a center to a vehicle between a beacon and a center in a communication control device, wherein the message is divided into a plurality of blocks. If the block number in each frame is normal after the transfer is completed, the reception is completed. ・ When the normal message is sent from the receiving side, the reception is completed when the frame that constitutes the message is single. -Do not send a normal message from the receiver. Further, when the message is transferred for each frame divided into a plurality of blocks, when the message is composed of a single frame and the data area has a surplus, the data is corrected in the data area so that the receiving side can perform error correction. A sign is provided.

[0008]

According to the beacon communication control apparatus of the present invention, the message is transferred for each frame divided into a plurality of blocks, and if the block number in each frame is normal after the transfer is completed, the reception completion / normal message is received. When the message is transmitted from the receiving side, when the number of the frames that make up the message is single, the reception side does not send the reception complete / normal message so that the order check of the block header number does not occur for the single frame. It is possible to omit the message indicating that reception is completed and normal, and it is possible to further simplify the communication procedure in which one frame message is often communicated. Further, when the message is transferred for each frame divided into a plurality of blocks, when the message is composed of a single frame and the data area has a surplus, the data is corrected in the data area so that the receiving side can perform error correction. By providing the code, single error correction / double error detection can be performed, and as a result, the retransmission time can be shortened.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a communication protocol control standard in a beacon communication control device according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating a communication protocol format used in the present embodiment. FIG. 1A shows the control procedure at the center which is the transmission side, and FIG. 1B shows the control procedure at the beacon which is the reception side. The reverse is also present, but is omitted for simplification of description. The modem procedure units 1 and 16 of FIG. 1 will be described. Channels are separated by frequency division (low channel: 1200 ± 0.5 Hz, high channel: 2400 ± 1.0 Hz), and as a general matter, the transmission method is: full-duplex / flag synchronization type, and the coding method is NR.
Z, transmission rate: 2,400 bps, modulation method: 60-ary QAM (quadrature amplitude modulation) for each channel
0 baud, synchronous transmission, communication standard: CCITT V22b
It is compliant. Regarding the transmission line, the adaptive line is: a 2-line or 4-line dedicated line (equivalent to NTT 0.3 to 3.4 kHz band line), or a 2-line or 4-line private line,
Point-to-point line, scrambled.

FIG. 3 shows a retraining sequence for performing a synchronization recovery operation between modems. As shown in this figure, this procedure is for performing a synchronization recovery operation between the modems when the power is turned on or when the equalizer is disconnected.
FIG. 4 is a diagram for explaining the station configuration of the LAPB procedure in the HDLCs 2 and 15 of FIG. As shown in (a) and (b) of the figure, in HDLC, there are two types of information to be communicated, a command and a response, and information transmitted from a primary station (center) to a secondary station (beacon) is a command, Information transmitted from the secondary station to the primary station is called a response. The complex station sends and receives both commands and responses. All frames are either commands or responses.
The HDLC data link includes an unbalanced data link and a balanced data link. In the unbalanced data link configuration, the primary station is a station that controls the data link,
This station has full responsibility for error control and recovery at the link level. The secondary station is a station that executes a data link control function according to an instruction from the primary station. This figure (c) is a figure which shows the structure of a balanced type data link, and a compound station is a station mutually responsible for data link control.

FIG. 5 is a diagram showing a frame structure of information communication in LAPB. As shown in this figure (a), the frame includes a flag, an address, a control unit, an information unit, and an FCS (Fra
meCheck Sequence) and flags. The address, control unit, and information unit are within the error control range. Further, the frame includes an information frame (I), a supervisory frame (S) and an unnumbered (U) frame. The information frame is a frame having information content to be communicated. It not only communicates information but also has a communication control function. The supervisory frame is a frame used for executing supervisory control of the link. It has no information section.
The unnumbered frame is a frame used for request / response of mode setting and reporting of abnormal condition. Some have an information section and some do not. As shown in this figure (b), the type of frame is identified by the data of the control unit. In this figure (b), N (s) is a transmission sequence number, N (r) is a reception sequence number, and b2 and b6 are low-order bits. S
Is a monitoring function bit, which defines a monitoring command / response. M is a modifier function bit, which defines an unnumbered command / response. P
/ F represents a pole / final bit.

FIG. 6 is a diagram showing types of LAPB commands and responses. The above-mentioned commands and responses include the types shown in this figure. FIG. 7 is a diagram for explaining the setting and disconnection of the data link. When LAPB is realized, parameter settings of T1 (response confirmation timer), N1 (maximum number of bits in information frame), N2 (maximum number of transmissions), and k (number of outstanding information frames) are set. As shown in FIG. 9A, a SABM (Set ABM) command is transmitted to set a data link. The partner station that received this command, if it can accept it, is a UA (Unnumbered).
It responds with an Acknowledge response, and if it cannot be accepted, DM (Disconnectnec)
Ted Mode) response. To disconnect the data link, a DISC (Disconnect) command is transmitted, and the partner station responds with a UA response. Communication between beacon centers is performed after connecting to the modem, and then LAPB
The data link of the procedure is connected. This state is a data transferable state, and data can be transferred individually. When the data transfer is completed, the link is disconnected according to the LAPB procedure.

FIG. 8 shows the message procedure parts 4 and 12 of FIG.
FIG. 9 is a diagram illustrating a message frame format in FIG. 9, and FIG. 9 is a diagram illustrating a blocking format.
In the format shown in FIG. 8, a message communicated between the beacon and the center is transferred by blocking / deblocking. Regarding blocking in the message transfer procedure protocol, one frame in the LAPB procedure corresponds to one block. As shown in FIG. 9, the sender sends a 256 message.
Divide by byte unit and add message block number,
Divide and transfer one block at a time. Then, the message is transferred using the corresponding priority level according to its transfer priority. As for transmission, messages can be multiplexed (priority message interruption) and transmitted up to a maximum of 4 messages per communication direction according to the message transfer priority. The receiving side will assemble the message according to the message block number for each priority level. The message block header manages message blocks by priority level and message block number so that messages to be transferred can be multiplexed and transferred. A continuous number starting from 0 is added to the divided message blocks. The MSB of the final message block number is set to 1. Note that the message block number 0 has the meaning of reception reset of the corresponding priority level.

FIG. 10 is a diagram showing a message block of reception completion. In the results shown in this figure, 00H is normal reception, 01H is abnormal reception, and more specifically, it is always 0 when normal reception.
Represents 0H, and when abnormally received, 01H is an invalid message block number (when the block numbers are not consecutive), 02H is an invalid message block format,
03H represents memory congestion (no receiving buffer memory).

FIG. 11 is a diagram for explaining the correction code adding section 13 of FIG. The correction code adding unit 13 shown in the figure is a Hamming code encoder. FIG. 12 shows the error correction unit 32 of FIG.
It is a figure explaining. The error correction unit 32 shown in the figure is a Hamming code decoder. A list of user data to be transmitted / received by the applications 5 and 11 is shown below in Table 1.

[0016]

[Table 1]

In the above table, the communication direction indicates the transmission from the beacon to the center, and the downlink indicates the transmission from the center to the beacon. The contents of each message are explained below. Table 2 shows No. 1 represents an operation state notification (beacon → center). This is to notify the center from the beacon when the operation mode of the beacon is changed, when the device abnormality is changed, or when an operation mode notification request is received. Message type: 01H,
Data size: 8 bytes.

[0018]

[Table 2]

Table 3 shows No. 2 represents the change of the operation mode (center → beacon). The message type is 02H and the data size is 1 byte.

[0020]

[Table 3]

No. The operation state notification request 3 (center → beacon) requests the operation state notification of the beacon and causes the return beacon to transmit the operation state notification. The message type is 03H and the data size is 0. No. The center initial notification 4 (center → beacon) deletes all the dynamic information registered by this notification and restores the reduced static information. The message type is 04H and the data size is 0.

Table 4 shows No. 5 dynamic information registration (center →
Beacon). This is to register all static information from the center. The message type is 10H and the data size is 2 + 122 × n bytes.

[0023]

[Table 4]

Table 5 shows No. 6 represents a static information transmission item change request of 6 (center → beacon). This sets items to be wirelessly transmitted for each of the main direction and the sub direction based on the static information stored in the non-volatile memory. The wireless transmission item is designated by a large section indicated by a bit pattern in the information menu format. The message type is 11H and the data size is 4 bytes.

[0025]

[Table 5]

Table 6 shows No. 7 Dynamic information registration (Center →
Beacon). This is to register the dynamic information (all information of one large section) such as the center, and the center needs to transmit all the information even if a part of the information changes, and the update of the actual wireless transmission information is not possible. , No. The dynamic information update notification of No. 9 is used. The message type is 20H and the data size is 2 + 122 × n bytes.

[0027]

[Table 6]

Table 7 shows No. 8 Dynamic information deletion (Center →
Beacon). This also deletes the dynamic information (all of one large section information). However, the actual wireless transmission information update is No. This is done by the dynamic information update notification of 9. The message type is 22H and the data size is 1 byte.

[0029]

[Table 7]

Table 8 shows No. 9 represents a dynamic information update notification of 9 (center → beacon). This is to update the information collectively by this notification at the time of registration / deletion of dynamic information, and process the update and deletion requests of the dynamic information received from the previous update notification to the current update notification in the order of reception. In addition, the contents of the dynamic information menu after updating the dynamic information are updated to the contents of the dynamic information menu set by this notification. The message type is 23H and the data size is 4 bytes.

[0031]

[Table 8]

No. The beacon transmission content inquiry 10 (center → beacon) is an inquiry of a beacon number, a coordinate, and a large section list being wirelessly transmitted, and returns a return inquiry result to the request source. The message type is 30H and the data size is 0. Table 9 shows No. 11 represents a beacon transmission content inquiry response (beacon → center). This is a response transmitted from the beacon in response to a beacon inquiry. The message type is 31H and the data size is 12 + 3 + n.

[0033]

[Table 9]

No. 12 represents a static information read request (center → beacon). This is a request for reading static information from the beacon and returning the read result to the request source. The message type is 40H and the data size is 0. Table 10 shows No. 13 shows the result of reading static information 13 (beacon → center). This is to send back the result of reading the static information from the beacon.
The message type is 41H and the data size is 6 + 1
It is 22 × n bytes.

[0035]

[Table 10]

Table 11 shows No. 14 represents a dynamic information read request (center → beacon). This is a request for reading the dynamic information to the beacon and returning the return reading result to the request source. The message type is 50H and the data size is 1 byte.

[0037]

[Table 11]

Table 12 shows No. The 15 dynamic information read results (beacon → center) are shown. This is to send back the result of reading the dynamic information from the beacon. The message type is 51H and the data size is 6
It is + 122 × n bytes.

[0039]

[Table 12]

Table 13 shows No. 16 represents a center no-communication timer registration (center → beacon). This registers the center no-communication timer. The message type is 70H
And the data size is 2 bytes.

[0041]

[Table 13]

In conclusion, it can be said that in actual communication between beacon centers, many messages end in one block, and 12 out of 16 messages are one block. 13 to 17 are diagrams for explaining specific examples (Nos. 1 to 5) of the message transfer procedure. 13 shows an example of transmission success, FIG. 14 shows an example of transmission failure (abnormal response of reception completion), and FIG. 15 shows an example of transmission failure (no response of reception completion / timeout).
FIG. 16 is a diagram showing transmission failure (reception completion no response / timeout) retransmission recovery, and FIG. 17 is a transmission failure (reception completion response transmission error / timeout) retransmission recovery. One frame corresponds to one block in the message block used in the message transfer procedure. The sender divides the message into message blocks and sends them. When all the messages have been received, the receiving side returns reception complete / normal. If the message block number order is abnormal, reception complete / error is returned. It is assumed that the sender has successfully transmitted the message when the reception completion / normality is returned. Also,
If the message "Reception complete / abnormal" is returned or the message "Reception complete / Normal" is not returned within a fixed time after the message is sent, it is determined that the message could not be sent correctly, and the resend process is performed.
The above has described the case where there are a plurality of message blocks (two or more).

FIG. 18 is a view for explaining the transfer procedure when it is composed of one frame message. 1 as shown in this figure
In the case of a frame message (see FIG. 8), even if the message block header is normally received, the reception completion / normal is not issued to the transmitting side. In the case of a plurality of message blocks, it is necessary to check the order of the block header numbers, but if it is 1, it is unnecessary and therefore all of them have been returned as normal in the past, and this procedure was useless. For this reason, as described above, communication of one-frame message is quite large, so it is judged whether this is one frame based on the information such as the data size of the message header in FIG. 8 and the message of reception completion / normal is omitted. This simplifies the communication procedure. Because VIC
Since the communication between the S beacon centers is composed of the modem connection, the HDLC connection, and the beacon message transfer connection, a large number of confirmation messages are required in the transmission of one message. Because it will be simpler.

FIG. 19 is a diagram showing the structure of a one-frame message provided with an error correction code when it is composed of one-frame message. As shown in FIG.
A frame is composed of 258 bytes, and a message block is shown in which a message header of 6 bytes is further added to the data, and 11 of 16 messages in Table 1 have a block length of 16 bytes or less. Therefore, as shown in this figure (b), the data length is 8
As bytes, this is detected by the information such as the data size of the message header in FIG.
A 2-byte (7.4) cyclic Hamming error correction code is provided so that the conventional block length is 16 bytes and is 28 bytes. This is formed by the correction code addition unit 13 in FIG.
When the RC error generating unit 31 detects an error, the error correcting unit 32 corrects the error with the correction code, and the CRC checking unit 33 checks the error again. If there is an error in this check, a resend is requested. In this way
Since the single error correction / double error detection is performed, the retransmission time can be shortened.

[0045]

As described above, according to the present invention, a message is transferred for each frame divided into a plurality of blocks, and if the block number in each frame is normal after the transfer is completed, a message of reception completion / normal is sent. When sending from the receiving side, when the number of frames that make up the message is single, the receiving side does not send the message of reception completion / normal, so the message of reception completion / normal can be omitted. However, the communication procedure can be simplified considerably. Further, when transferring a message for each frame divided into a plurality of blocks, a correction code is added to the data area so that the receiving side can perform error correction when there is a single frame composing the message and there is a surplus in the data area. By providing the single error correction / double error detection, the resending time can be shortened as a result.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a communication protocol control procedure in a beacon communication control device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a communication protocol format according to the present embodiment.

FIG. 3 is a diagram showing retraining for performing a synchronization recovery operation between modems.

FIG. 4 is a diagram showing a station configuration of a LAPB procedure in HDLCs 2 and 15 of FIG.

FIG. 5 is a diagram showing a frame structure of information communication in LAPB.

FIG. 6 is a diagram showing types of LAPB commands and responses.

FIG. 7 is a diagram illustrating installation and disconnection of a data link.

FIG. 8 is a diagram showing a message format in message procedure units 4 and 12 of FIG. 1;

FIG. 9 is a diagram showing a blocking format.

FIG. 10 is a diagram showing a message block of reception completion.

FIG. 11 is a diagram illustrating a correction code adding unit 13 in FIG. 1.

12 is a diagram illustrating an error correction unit 32 in FIG.

FIG. 13 is a diagram illustrating a specific procedure (1) of a message transfer procedure.

FIG. 14 is a diagram illustrating a specific (second) of a message transfer procedure.

FIG. 15 is a diagram illustrating a specific (part 3) of a message transfer procedure.

FIG. 16 is a diagram illustrating a specific (part 4) of a message transfer procedure.

FIG. 17 is a diagram illustrating a specific (part 5) of the message transfer procedure.

[Fig. 18] Fig. 18 is a diagram for describing a transfer procedure in the case of being composed of one frame message.

[Fig. 19] Fig. 19 is a diagram illustrating the configuration of a 1-frame message provided with an error correction code when it is composed of the 1-frame message.

FIG. 20 is a diagram showing a system configuration of VICS.

FIG. 21 is a diagram illustrating an outline of a VICS communication protocol.

FIG. 22 is a block diagram illustrating in more detail a reception control procedure using a beacon.

FIG. 23 is a diagram illustrating a communication procedure between a conventional VICS center and a beacon.

[Explanation of symbols]

 1, 16 ... Modem procedure section 2, 15 ... HDLC procedure section 31 ... CRC error generation section 32 ... Error correction section 33 ... CRC check section 4, 12 ... Message procedure section 5, 11 ... Application section 13 ... Correction code addition section 14 … CRC adder

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Claims (2)

[Claims] 1. A communication control device for transferring a message between a beacon for providing information from a center to a vehicle and a center, wherein the message is transferred for each frame divided into a plurality of blocks, and after the transfer is completed. If the block number in each frame is normal, when the reception side sends a reception complete / normal message, the reception side does not send the reception completion / normal message when the frame that constitutes the message is single. Beacon communication control device characterized by the above. 2. A communication control device for transferring a message between a beacon for providing information from a center to a vehicle and a center, wherein the message is transferred in each frame divided into a plurality of blocks. A beacon communication control device, wherein a correction code is provided in the data area so that a receiving side can perform error correction when a single frame forming a message has a surplus in the data area.