JP4697804B2 - Road-to-vehicle communication method and road-to-vehicle communication device - Google Patents

Description

  The present invention relates to a road-to-vehicle communication method and a road-to-vehicle communication apparatus that perform data communication with an in-vehicle communication apparatus using wireless communication based on narrow area communication.

  Conventionally, as a kind of communication method by spot communication with limited communication area, full-duplex communication using different frequencies for communication from the base station to the mobile station and communication from the mobile station to the base station is called, and the communication frame is called a slot. A synchronous time-division communication method in which time division is performed in a fixed-length section is known. As a communication method based on this synchronous time-division communication method, even when other data is continuously transmitted during retransmission of the transmitted data, the received communication device newly receives the duplicate received data. A communication method (for example, refer to Patent Document 1) that can determine whether the received data is received, or communication that enables reception of message data that should be received even when duplicate data is received at the base station A method (for example, see Patent Document 2) has been devised.

  On the other hand, in recent years, road-to-vehicle communication by narrow-area communication (DSRC (Dedicated Short Range Communication)) has been studied as next-generation ITS (Intelligent Transport System) communication. In this road-to-vehicle communication, information is transmitted from a base station communication device called a road-to-vehicle communication device in a broadcast format and received by an in-vehicle communication device mounted on each vehicle. The application range of the service by the narrow area communication includes, for example, a highway service area and a parking area.

  In addition, the road-vehicle communication device is connected to an IP network that is also used for the Internet, for example, and the in-vehicle communication device exchanges data with a server device or system on the IP network via the road-vehicle communication device. It is also considered to do.

  When using DSRC for a communication layer corresponding to the lower layer of the communication system layer and configuring a communication system using TCP / IP communication for an application layer corresponding to the upper layer, these different communication methods, DSRC and TCP / IP, are used. In order to synchronize with communication and to bridge data communication, it is necessary to provide an adaptive layer in the middle. As an adaptive layer used for data communication on DSRC, standard specifications of an application sublayer (hereinafter referred to as ASL) have been established in ARIB STD-T88 1.0 version.

  When data is transmitted from the road-to-vehicle communication device to the in-vehicle communication device, communication is performed by synchronous time division communication in units of communication frames configured by time division into a plurality of slots. There are four types of slots: FCMS (Frame Control Message Slot), MDS (Message Data Slot), ACTS (ACTivation Slot), and WCNS (Wireless Call Number Slot). The FCMS is located at the head of a frame and has slot information such as allocation of transmission / reception slots in the frame. The MDS is a slot that stores communication data and performs transmission / reception, and can store 193 bytes of data when the frame is modulated by the QPSK method and 65 bytes of data when the frame is modulated by the ASK method. The ACTS is an uplink-dedicated slot used when a connection request is made from the in-vehicle communication device that has entered the communication area to the road-vehicle communication device. The WCNS is transmitted to the road-to-vehicle communication device in a slot that contains the unique status of the in-vehicle communication device.

  Data for the in-vehicle communication device is stored in the MDS and transmitted from the application layer, which is an upper layer of the road-vehicle communication device, but it is necessary to divide the data into sizes that can be stored in the MDS. FIG. 10 is a diagram schematically showing a data transmission process in the conventional DSRC. In the figure, data obtained from a file is divided into a plurality of pieces, a header is assigned to each piece of divided data, and each piece of divided data is assigned to a communication frame for transmission. This series of processing is repeated for a certain period. In this case, the divided data is the same, but a different header is assigned.

JP 2002-44094 A JP 2002-315047 A

However, the conventional road-to-vehicle communication method has the following problems.
(1) Since the data is divided into a plurality of parts, a header is assigned to each divided data, and then a series of processes for assigning to the communication frame and transmitting are repeated for the same data, the use of the CPU (central processing unit) The rate is high and overall processing performance is poor.
(2) Since the transfer rate in the communication layer is constant, the upper layer must transmit data according to the transfer rate in the communication layer. Therefore, it is necessary to provide a buffer for temporarily storing the divided data, and the cost increases accordingly.
(3) When changing the data to be transmitted from one file to a different file, it takes time until the data after the change is actually transmitted, resulting in poor responsiveness and the time until transmission starts. Slots (MDS) are wasted.

  The present invention has been made in view of such circumstances, can reduce the load on the CPU, eliminates the need for a buffer for temporarily storing data, and further transmits data to be transmitted from one file to a different file. It is an object of the present invention to provide a road-to-vehicle communication method and a road-to-vehicle communication device that can minimize the deterioration of responsiveness and associated slot waste even if the change is made.

The above object is achieved by the following method or configuration.
(1) In a road-to-vehicle communication method in which a road-to-vehicle communication device transmits data to a vehicle equipped with an in-vehicle communication device, a data division step of dividing transmission data and assigning headers each including identification information; A data accumulating step of accumulating a plurality of divided data obtained in the data dividing step in an accumulating unit; and a data transmitting step of allocating and transmitting the plural divided data accumulated in the accumulating unit to a communication frame. .

  According to the above method, since the transmission data is divided and each of which is assigned and stored with a header including identification information, the accumulated divided data is allocated to the communication frame and transmitted, so the transmission data is divided, The load on the CPU can be reduced compared to a method of repeating all of the process of assigning a header to each piece of divided data and the process of assigning each piece of divided data attached with a header to a communication frame. Further, since it is not necessary to provide a buffer for temporarily holding the divided data in the process of dividing the data, the cost can be reduced.

(2) In a road-to-vehicle communication method in which a road-to-vehicle communication device transmits the same data to an unspecified number of vehicles equipped with an in-vehicle communication device, a data division step for dividing the transmission data into a plurality of pieces and identification information is divided An identification information adding step for adding data, a data storage step for storing the divided data to which the identification information is added in the identification information adding step in the storage unit, and the identification information stored in the storage unit A data transmission step of allocating the plurality of divided data to a communication frame and transmitting the data.

  According to the above method, even if the identification information for identifying each divided data is smaller than the total number of divided data, the first and last divided data are not the same identification information during repeated transmission. Thereby, data can be assembled without error on the receiving side, that is, the in-vehicle communication device side. Establishing incorrect information reassembly, especially when repetitive identification information is assigned to all of a plurality of divided data using a smaller number of pieces of identification information than the number of transmission data divided by the data division process Decrease.

(3) In the road-to-vehicle communication method according to (2) above, in the data accumulation step, one transmission data is accumulated in a plurality of the accumulation units, and in the identification information providing step, it is accumulated in each accumulation unit. The identification information which limited at least one use frequency different from the said other storage part is provided to the head area | region of the some data to which the said identification information was provided.

  According to the above method, since at least one piece of identification information that limits the number of times of use different from other storage units is provided in the head region of a plurality of data to which identification information stored in each storage unit is assigned, Therefore, when data is switched between storage units, that is, when data to be transmitted is changed from one file to a different file, the time required until the changed data is actually transmitted is short. That's it. As a result, the responsiveness is improved and the waste of slots constituting the communication frame can be minimized.

(4) In the road-to-vehicle communication method according to (3) above, in the data accumulation step, a plurality of transmission data is accumulated in one of the accumulation units or is distributed and accumulated in the plurality of accumulation units.

  According to the above method, the same identification information does not continue even if a plurality of pieces of transmission data are stored only in one storage unit or are distributed and stored in a plurality of storage units. Thereby, data can be assembled without error on the receiving side, that is, the in-vehicle communication device side.

(5) In a road-to-vehicle communication device that repeatedly transmits the same data to an unspecified number of vehicles equipped with an in-vehicle communication device, data division that divides transmission data into a plurality of data and assigns a header including identification information to each of them. Means, data storage means for storing a plurality of pieces of divided data obtained by the data dividing means, and data transmission means for repeatedly assigning and transmitting the plurality of pieces of divided data stored in the data storage means to communication frames; Including a transmitter.

  According to the above configuration, since the transmission data is divided and each header is added and stored with identification information, the accumulated divided data is repeatedly assigned to the communication frame and transmitted. The load on the CPU can be reduced as compared with the conventional technique that repeats all of the process of assigning a header to each divided data and the process of assigning each divided data to which the header is assigned to a communication frame. Further, since it is not necessary to provide a buffer for temporarily holding the divided data in the data dividing means, the cost can be reduced.

(6) In a road-to-vehicle communication device that repeatedly transmits data to a vehicle equipped with an in-vehicle communication device, data dividing means for dividing the transmission data into a plurality of pieces, and identification information of the divided data divided by the data dividing means Identification information giving means for repeatedly giving to all of the plurality of divided data using the data, data storage means for storing the divided data to which the identification information is given by the identification information giving means, and the data storage means And a data transmission means for allocating and transmitting a plurality of divided data to which the identification information stored in the communication frame is assigned to a communication frame.

  According to the above configuration, even if the identification information for identifying each divided data is smaller than the total number of divided data, the first and last divided data are not the same identification information during repeated transmission. Thereby, data can be assembled without error on the receiving side, that is, the in-vehicle communication device side.

(7) The road-to-vehicle communication device according to (6), wherein the data storage unit includes a plurality of the data storage units, and the data storage unit stores one transmission data in a distributed manner in the plurality of storage units. The assigning means assigns at least one one-time use identification information different from the other accumulating means to the head region of the plurality of data to which the identification information accumulated in each accumulating means is given.

  According to the above configuration, at least one one-time use identification information different from the other storage means is provided in the head region of the plurality of data to which the identification information stored in each storage means is given. From this, when switching data between storage means, that is, when changing data to be transmitted from one file to a different file, the time required until the changed data is actually transmitted is short. That's it. As a result, the responsiveness is improved and the waste of slots constituting the communication frame can be minimized.

(8) In the road-vehicle communication device according to (7), the data storage unit stores a plurality of transmission data in one or more of the storage units.

  According to the above configuration, a plurality of pieces of transmission data are stored in one or more storage units, so that the same identification information does not continue. Thereby, data can be assembled without error on the receiving side, that is, the in-vehicle communication device side.

  According to the present invention, it is possible to reduce the load on the CPU, eliminate the need for a buffer for each communication layer for temporarily storing data, and respond even if data to be transmitted is changed from one file to another file. It is possible to minimize the deterioration of sex and the accompanying slot waste.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing schematic configurations of a road-to-vehicle communication apparatus according to Embodiment 1 of the present invention and an in-vehicle communication apparatus that receives information transmitted from the road-to-vehicle communication apparatus. In the figure, the road-to-vehicle communication device 1 according to the present embodiment transmits various types of information using wireless communication by DSRC. The in-vehicle communication device 2 receives various information transmitted from the road-vehicle communication device 1. As information transmitted from the road-to-vehicle communication device 1, when the road-to-vehicle communication device 1 is applied to, for example, a service area or a parking area of an expressway, traffic information, regulation information, road information, facility guidance, sightseeing information, etc. Can be considered. Normally, these pieces of information are not received by the in-vehicle communication device 2 at a time (that is, the in-vehicle communication device 2 cannot acquire all the information at one time), so that it is repeatedly transmitted. The applicable range of road-to-vehicle communication includes a gas station, a parking lot, a fast food restaurant, a convenience store, and the like, and information corresponding to each applicable range is transmitted.

  The road-vehicle communication device 1 includes an application processing unit 11 that is an upper layer, a communication processing unit 21 that includes an adaptive layer that is an intermediate layer and a communication layer that is a lower layer, and a radio unit 31 that is a physical layer. The application processing unit 11 includes a data generation unit 111 and an application data division unit 112. The application data division unit 112 roughly divides the application data generated by the data generation unit 111 and outputs the application data. The communication processing unit 21 subdivides the data roughly divided by the application processing unit 11, and also includes a data dividing unit 211 that assigns a header including identification information to each of the plurality of subdivided divided data, and a data dividing unit The data distribution unit 212 that distributes the divided data from 211 to each of the two storage units (1) 213 and (2) 214, and the two storage units (1) 213 and (2) that store the divided data from the data distribution unit 212 2) 214, a slot allocation unit 215 that allocates each divided data stored in each of the storage units (1) 213 and (2) 214 to an MDS (Message Data Slot), and a communication frame from the MDS to which the divided data is allocated A frame generation unit 216 that generates a data, a data distribution unit 212, and a slot allocation unit 215. And a control unit 217 for respective control.

  FIG. 2 is a diagram schematically showing data division processing in the data division unit 211 of the communication processing unit 21. This figure shows a case where the pre-division data 200 that is the source of the division is divided into three, and each divided data 201 is given a header 202 including identification information 203. Note that the data length of the divided data may be constant or different. In the present embodiment, the number of data divisions in the data division unit 211 is set to be the same as or less than the total number of identification information, and each divided data can be identified without duplication of identification information.

  FIG. 3 is a diagram schematically showing slot allocation and frame generation processing of the communication processing unit 21. In the figure, a communication frame (one frame) is composed of one frame control message slot (FCMS) and four message data slots (MDS), and divided data A-1 to A-6 are allocated to each MDS. The divided data A-1, A-2, A-3, and A-4 are respectively assigned to the MDS of the left communication frame shown in FIG. A-6, A-1, and A-2 are assigned respectively. Note that the communication frame shown in FIG. 3 is an example, and the number of MDSs constituting the frame is arbitrary. Further, the allocation of the divided data to the MDS may be regular or irregular.

  Returning to FIG. 1, the control unit 217 controls the data distribution unit 212 to distribute the divided data from the data division unit 211 to the storage unit (1) 213 and the storage unit (2) 214. Thereafter, when generating a frame from the accumulated divided data, the slot allocating unit 215 is controlled to allocate the divided data to the MDS. The frame generation unit 216 generates a communication frame from the MDS to which the divided data is allocated, and outputs the communication frame to the radio unit 31 that is a physical layer. The radio unit 31 modulates and transmits the communication frame generated by the frame generation unit 216 using an ASK (Amplitude Shift Keying) method, a QPSK (Quadrature Phase Shift Keying) method, or the like.

  The road-to-vehicle communication device 1 according to the present embodiment is configured as described above, and the divided data generated by the application processing unit 11 is subdivided by the data dividing unit 211 of the communication processing unit 21 and further divided. A header including identification information is added to the data. Then, the divided data to which the header is added is distributed by the data distribution unit 212 to the storage unit (1) 213 and the storage unit (2) 214, respectively. Then, the division data accumulated in the accumulation unit (1) 213 and the accumulation unit (2) 214 is repeatedly allocated to the MDS to generate a communication frame, and is transmitted from the radio unit 31. FIG. 4 is a diagram schematically illustrating the data transmission process of the present embodiment. After dividing the data of one or a plurality of files and adding a header including identification information to each of them, the step of storing (I) and allocating the stored data to a communication frame and repeatedly transmitting for a certain period of time It consists of process (II), process (I) is performed only once, and process (II) is performed repeatedly.

  On the other hand, the in-vehicle communication device 2 includes an application processing unit 12 including a data reproducing unit 121 and an application data assembling unit 122, a communication processing unit 22 including a data assembling unit 221 and a frame reproducing unit 222, and a wireless unit 32. Composed. The wireless unit 32 performs wireless communication with the road-to-vehicle communication device 1, receives a modulated wave transmitted from the road-to-vehicle communication device 1, demodulates the communication frame, and outputs the demodulated frame to the frame reproduction unit 222. The frame reproducing unit 222 reproduces the demodulated communication frame and outputs it to the data assembling unit 221. The data assembling unit 221 analyzes the header of the divided data allocated to the MDS constituting the communication frame and assembles it in a state before the slot allocation. Then, the assembled data is output to the application data assembling unit 122. The application data assembling unit 122 assembles application data from the data from the data assembling unit 221 and outputs it to the data reproducing unit 121. The data reproducing unit 121 reproduces original data from the data assembled by the application data assembling unit 122.

  Thus, according to the road-to-vehicle communication device 1 of the present embodiment, one or a plurality of file data is divided, and the divided data accumulated after the headers including the identification information are added and accumulated. Is repeatedly assigned to the communication frame and transmitted, so that the process of dividing the transmission data, the process of assigning a header to each divided data, and the process of assigning each divided data to which the header is assigned to the communication frame are all repeated. In comparison, the load on the CPU (here, the control unit 217) can be reduced. In addition, since it is not necessary to provide the data dividing unit 211 with a buffer for temporarily holding the divided data to which the header is added, the cost can be reduced.

  In the present embodiment, two storage units (1) 213 and (2) 214 are provided. However, the number of storage units is not limited, and may be three or more.

(Embodiment 2)
Since the road-to-vehicle communication apparatus according to Embodiment 2 of the present invention has substantially the same configuration as the road-to-vehicle communication apparatus 1 of Embodiment 1 described above, FIG. Also, since the process of dividing data and the process of assigning divided and accumulated data to communication frames are the same, FIGS. 2 and 3 are used when necessary for the convenience of explanation. The difference from the road-to-vehicle communication device 1 according to the first embodiment is that the data dividing unit 211 subdivides the data from the application processing unit 11, and the control unit 217 supplies identification information to each of the plurality of subdivided divided data. It is a point to add a header including. Note that the road-to-vehicle communication apparatus of the present embodiment is denoted by reference numeral 1A to be distinguished from the road-to-vehicle communication apparatus 1 of the first embodiment.

  In the data dividing unit 211 described in the first embodiment, a header including identification information is assigned to each divided data. When a standard is provided for the number of identification information, data exceeding the standard is provided. When the data is divided, identification information can be given to all divided data, but overlapping identification information is used. For example, when the number of pieces of identification information is standardized to 5 bits (32 from 0 to 31) and the data is divided into 33 pieces, as shown in FIG. The same identification information is given. When the divided data is repeatedly transmitted, the first divided data is transmitted after the final divided data is transmitted, so the identification information in the header is the same. In this case, the receiving side, that is, the in-vehicle communication device 2 cannot distinguish the data from the header, and the data (pre-division data) cannot be reproduced normally. In the present invention, even when a standard is provided for the number of identification information, a header can be added so that the identification information does not continuously take the same value.

  The control unit 217 of the communication control unit 21 has an identification information management table 217T as shown in FIG. 6. The control unit 217 uses the identification information management table 217T to indicate identification information to be added to the divided data. Each item of “identification information”, “use” indicating the use of the identification information, “corresponding storage unit” indicating the storage location of the divided data, and “allocation” indicating the divided data to which the identification information is assigned are managed. Here, the identification information = 0 to 13 is used for repetition, and is given to each divided data of the data 1 stored in the storage unit (1) 213. Further, identification information = 14 to 27 is also given to each divided data of the data 2 stored in the storage unit (2) 214 for repetition. The identification information 28 is given to the head of the data 1 stored in the storage unit (1) 213 for one-time use. The identification information 29 is also given second from the beginning of the data 1 stored in the storage unit (1) 213 for one-time use. The identification information 30 is given to the head of the data 2 stored in the storage unit (2) 214 for one-time use. The identification information 31 is also given second from the top of the data 2 stored in the storage unit (2) 214 for one-time use.

  FIG. 7 is a diagram schematically showing the divided data stored in the storage unit (1) 213 and the storage unit (2) 214, and the identification information given to each divided data. The identification information 28 located at the head of the data in the storage unit (1) 213 and the identification information 29 located next to it indicate that the data is 1, and the receiving side, that is, the in-vehicle communication device 2 receives them. Thus, it can be determined that the subsequent divided data is data 1. Similarly, the identification information 30 located at the head of the data in the storage unit (2) 214 and the identification information 31 located next to it indicate that the data is 2, and the receiving side, ie, the in-vehicle communication device 2 , It can be determined that the subsequent divided data is data 2. Even if data is switched, that is, data 1 is changed to data 2 (or vice versa), data 1 has identification information 28 and 29, and data 2 has identification information 30 and 31. The communication device 2 does not assemble incorrect data.

  The identification information 0 to 13 is repeatedly used and given to each divided data of the data 1. In this case, the same identification information may be assigned to the same divided data or different divided data. For example, the divided data to which identification information = 0 is assigned first, the divided data to which identification information = 0 is assigned next, and the divided data to which identification information = 0 is assigned next (the same applies hereinafter) Even if they are different, they may all be the same. However, when the identification information is given again after one round, the same applies. For example, in the first time, divided data (A) to which identification information = 0 is assigned first, divided data (B) to which identification information = 0 is assigned next, and divided information to which identification information = 0 is assigned next. Data (C) is set to have the same correspondence in the second time. The same applies to the third and subsequent times. In this way, the identification information = 0 to 13 is repeatedly given, and the same identification information is not continued by arranging the divided data corresponding to each identification information = 0 to 13 to be the same every round. Identification information can be assigned to all divided data. Thus, the receiving side, that is, the in-vehicle communication device 2 does not assemble erroneous data.

  Similarly, the identification information 14 to 27 is repeatedly used and given to the divided data of the data 2. In this case, the same identification information may be assigned to the same data or different data. For example, the divided data to which identification information = 14 is assigned first, the divided data to which identification information = 14 is assigned next, and the divided data to which identification information = 14 is added next (the same applies hereinafter) Even if they are different, they may all be the same. However, when the identification information is given again after one round, the same applies. For example, in the first time, divided data (P) to which identification information = 14 is assigned first, divided data (Q) to which identification information = 14 is assigned next, and further, identification information = 14 is assigned next. The data (R) is set to have the same correspondence in the second time. The same applies to the third and subsequent times. In this way, the identification information = 14 to 27 is repeatedly given, and the divided data corresponding to each identification information = 14 to 27 is arranged to be the same every round, so that the same identification information does not continue. Identification information can be assigned to the divided data. Thereby, the receiving side, that is, the in-vehicle communication device 2 does not assemble erroneous data.

  Next, the operation of the road-to-vehicle communication device 1 of the present embodiment will be described with reference to the flowchart shown in FIG. In the figure, first, transmission data is generated by the data generation unit 111 (step S101), and data is divided by the application data division unit 112 (step S102). Next, the data divided by the application data dividing unit 112 is further divided by the data dividing unit 211 (step S103). After data division by the data dividing unit 211, it is determined whether there is data currently being transmitted (step S104). If there is data currently being transmitted (YES in step S104), the data is transmitted. It is determined whether the storage unit in use is the storage unit (1) 213 or the storage unit (2) 214 (step S105). If the storage unit currently used for transmission is the storage unit (1) 213, the divided data from the data dividing unit 211 is stored in the storage unit (2) 213 (step S107) and is currently used for transmission. If the storage unit is the storage unit (2) 214, the divided data from the data dividing unit 211 is stored in the storage unit (1) 213 (step S106). On the other hand, if there is no data currently transmitted in the determination in step S104 (in the case of NO), the divided data from the data dividing unit 211 is accumulated in the accumulating unit (1) 213 (step S106).

  After the division data from the data division unit 211 is accumulated in the accumulation unit (1) 213 or the accumulation unit (2) 214, the first division data is accumulated from the accumulation unit (1) 213 or (2) 214 that accumulated the division data. The communication frame is assigned (step S108). Next, from the divided data stored in the storage unit (1) 213 or (2) 214, the divided data to be allocated to the communication frame is acquired, the acquired divided data is allocated to the MDS, and the communication frame is generated. It is transmitted (step S109). Then, it is determined whether or not the last divided data stored in the storage unit (1) 213 or (2) 214 that has acquired the divided data has been allocated (step S110), and the last divided data is allocated ( If YES in step S110), the process returns to step S108. If the last divided data has not been allocated (NO in step S110), the data generation unit 111 determines whether to generate new transmission data (step S110). S111) If new transmission data is to be generated (YES in step S111), the process returns to step S101. If new transmission data is not to be generated (NO in step S111), the allocation target is the storage unit (1). The next divided data of 213 or (2) 214 is set (step S112). Steps S109 to S112 are repeated.

  Next, details of the operation of the data dividing unit 211 will be described with reference to the flowchart shown in FIG. In the figure, first, identification information for “one time use” and identification information for “repetition” are acquired (step S201). In the present embodiment, in the case of the storage unit (1) 213, the identification information for “one time use” is set to “28” and “29”, and the identification information for “repetition” is set to “0 to 13”. So get these values. In the case of the storage unit (2) 214, the identification information for “one time use” is set to “30” and “31”, and the identification information for “repetition” is set to “14 to 27”. Get the value. Hereinafter, the case of the storage unit (1) 213 will be described as an example.

  After obtaining the identification information for “one time use” and the identification information for “repetition”, the counter value is set to “0” (step S202). After acquiring each piece of identification information, the data from the application data dividing unit 112 is fetched and divided into a predetermined size or less (step S203). Here, for example, it is divided into 33 pieces. After the data is divided, it is determined whether or not the number assigned to the “one time limited” identification information exceeds the counter value (step S204). Since the initial counter value is “0”, the process proceeds to step S205, in which the identification information “for one-time use” is assigned to the identification information of the header of the divided data. In this case, identification information 28 is assigned. After assigning the identification information 28, “1” is added to the value of the counter (step S207). As a result, the value of the counter becomes “1”.

  After increasing the value of the counter, it is determined whether or not the data divided now is the last divided data of the data generated by the data generation unit 111 (step S208). Since it is not the last divided data, the process returns to step S204. In step S204, it is determined again whether the number assigned to the “one-time limited” identification information exceeds the counter value. Now, although the value of the counter is “1”, since it is less than the number of “2” assigned to the identification information of “one time limited”, the process proceeds to step S205. Then, identification information for “one time limitation” is assigned to the identification information of the header of the divided data. This time, identification information 29 is assigned. After assigning the identification information 29, “1” is added to the value of the counter (step S207). As a result, the value of the counter becomes “2”.

  Then, although the determination in step S208 is performed, since it is not the last divided data at the present time, the process returns to step S203 to divide the data to be equal to or smaller than the specified size, and then the number assigned to the identification information for “one time limited” is counted. It is determined whether or not the value exceeds (step S204). Since the value of the counter is “2” now, the process does not proceed to step S205 but proceeds to step S206. In step S206, identification information “for repetition” is periodically assigned to the identification information of the header of the divided data. That is, as shown in FIG. 7, identification information = 0 to identification information = 13 are assigned. When the first periodic assignment of identification information = 0 to identification information = 13 is completed, the process proceeds to step S208, where it is determined whether or not it is the last divided data, and the above-mentioned steps S203 to until the last divided data is reached. Step S208 is repeated. In this way, “one-time use only” identification information = 28, 29 and a plurality of “repetition use” identification information = 0 to identification information = 13 are assigned to data 1. Data 1 assigned with these identification information is repeatedly transmitted.

  Similarly, for the data 2 stored in the storage unit (2) 214, “one-time use only” identification information = 30, 31 and a plurality of “repetition use” identification information = 14 to identification information = 27 are assigned. . Data 2 assigned with these identification information is repeatedly transmitted.

  By repeatedly assigning identification information = 0 to identification information = 13 to data 1, the same identification information does not continue, and the receiving side, that is, the in-vehicle communication device 2 can assemble data 1 without error. Similarly, by repeatedly assigning identification information = 14 to identification information = 27 to data 2, the same identification information does not continue, and the receiving side, that is, the in-vehicle communication device 2 can assemble data 2 without error. it can. Furthermore, since “1 time limited” identification information = 28, 29 is assigned to the top of data 1 and “single time limited” identification information = 30, 31 is assigned to the top of data 2, respectively. It can be easily distinguished. In addition, the same identification information does not continue even if data 1 → data 2 and data 2 → data 1 are switched at any timing.

  Each divided data of data 1 and data 2 stored in the storage unit (1) 213 and storage unit (2) 214 is allocated to the MDS constituting the communication frame by the slot allocation unit 215. Then, a communication frame is generated by the frame generation unit 216 and output to the radio unit 31. The radio unit 31 modulates and transmits the communication frame generated by the frame generation unit 216 using the ASK method, the QPSK method, or the like.

  As described above, according to the road-to-vehicle communication device 1A of the present embodiment, the data of one or a plurality of files is divided, and the data is divided into pieces of data. Identification information and “for repetition” identification information are assigned. Then, the data 1 with the identification information is stored in the storage unit (1) 213, and the data 2 with the identification information is also stored in the storage unit (2) 214. For example, identification information “28, 29” is assigned to the head of the divided data obtained by dividing data 1, and identification information = 0 to 13 is repeatedly assigned to the remaining divided data. In addition, identification information “30 times 31” = 30, 31 is assigned to the head of the divided data obtained by dividing data 2, and “repeating” identification information = 14 to 27 is repeatedly assigned to the remaining divided data. Then, the divided data stored in the storage unit (1) 213 and the storage unit (2) 214 is repeatedly allocated to the communication frame and transmitted. Therefore, even when a standard is set for the number of identification information, the identification information does not continuously take the same value, and the first and last divided data do not become the same identification information during repeated transmission. . In addition, the same identification information does not continue even if data 1 → data 2 and data 2 → data 1 are switched at any timing. Needless to say, this embodiment has the same effect as that of the first embodiment.

  In the present embodiment, two storage units (1) 213 and (2) 214 are provided. However, the number of storage units is not limited, and may be three or more.

  In this embodiment, one data (transmission data) is distributed and stored in the two storage units (1) 213 and (2) 214, but a plurality of data (transmission data) is stored in one The data may be stored in the storage unit (1) 213 or (2) 214, or may be distributed and stored in the two storage units (1) 213 and (2) 214. Even if it does in this way, the allocation method of identification information does not change.

  In this embodiment, two pieces of identification information for “one time use” are provided. However, one or more pieces of identification information may be used, and how to handle the number of assignments depends on the system.

  In this embodiment, the identification information for “repetition” is divided into data 1 and data 2, but it may or may not be divided. Further, although the number of data is 2 (data 1, data 2), it is needless to say that it may be 2 or more.

  The present invention can reduce the load on the CPU, eliminate the need for a buffer for temporarily storing data, and even if the data to be transmitted is changed from one file to a different file, the responsiveness deteriorates and accompanying it This has the effect of minimizing slot waste, and can be applied to road-to-vehicle communication by DSRC.

1 is a block diagram showing schematic configurations of a road-vehicle communication device according to Embodiment 1 of the present invention and an in-vehicle communication device that receives information transmitted from the road-vehicle communication device. The figure which shows the data division | segmentation process of the road-vehicle communication apparatus which concerns on Embodiment 1 typically. The figure which shows typically the slot allocation of the road-vehicle communication apparatus which concerns on Embodiment 1, and a frame production | generation process. The figure which shows typically the data transmission process of the road-vehicle communication apparatus which concerns on Embodiment 1. FIG. The figure which shows the provision of identification information when the number of division | segmentation data is larger than the number of identification information The figure which shows an example of the identification information management table which the control part of the road-vehicle communication apparatus which concerns on Embodiment 2 of this invention has. The figure which shows typically the example of provision of the identification information in the road-vehicle communication apparatus which concerns on Embodiment 2. FIG. The flowchart for demonstrating operation | movement of the road-vehicle communication apparatus which concerns on Embodiment 2. FIG. Flowchart for explaining the operation of the data dividing unit of the road-vehicle communication apparatus according to the second embodiment. The figure which shows typically the data transmission process in the conventional road-to-vehicle communication

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A Road-to-vehicle communication apparatus 2 In-vehicle communication apparatus 11, 12 Application processing part 21, 22 Communication processing part 31, 32 Wireless part 111 Data generation part 112 Application data division part 121 Data reproduction part 122 Application data assembly part 200 Data before division | segmentation 201 Division Data 202 Header 203 Identification Information 211 Data Division Unit 212 Data Distribution Unit 213 Storage Unit (1)
214 Accumulator (2)
215 Slot allocation unit 216 Frame generation unit 217 Control unit 217T Identification information management table 221 Data assembly unit 222 Frame playback unit

Claims (4)

In the road-to-vehicle communication method in which the road-to-vehicle communication device transmits the same data to an unspecified number of vehicles equipped with the in - vehicle communication device,
A data dividing step for dividing the transmission data into a plurality of data;
An identification information giving step for giving identification information to the divided data;
The divided data to which the identification information is added in the identification information adding step is stored in a storage unit, one transmission data is stored in a plurality of the storage units, and in the identification information adding step, the divided data is stored in each storage unit. A data accumulating step of assigning identification information limited to at least one number of times of use different from other accumulating units to the top region of the plurality of data to which the identification information is given;
A data transmission step of allocating and transmitting a plurality of divided data to which the identification information stored in the storage unit is assigned to a communication frame;
Road-to-vehicle communication method comprising: The road-to-vehicle communication method according to claim 1, wherein, in the data accumulation step, a plurality of transmission data is accumulated in one of the accumulation units or is distributed and accumulated in the plurality of accumulation units . In a road-to-vehicle communication device that repeatedly transmits data to a vehicle equipped with an in-vehicle communication device,
Data dividing means for dividing the transmission data into a plurality of data;
Identification information giving means for repeatedly giving to all of the plurality of divided data using identification information of the divided data divided by the data dividing means;
A plurality of data storage means for storing the divided data to which the identification information is assigned by the identification information giving means;
Data transmitting means for allocating and transmitting a plurality of divided data to which the identification information stored in the data storing means is assigned to a communication frame;
Including a transmitter including
The data storage means distributes and stores one transmission data in a plurality of the storage means, and the identification information adding means is a head of a plurality of data to which the identification information stored in each storage means is added. A road-to-vehicle communication device characterized in that at least one one-time use identification information different from the other storage means is given to the area. The road-vehicle communication apparatus according to claim 3, wherein the data storage means stores a plurality of transmission data in one or more of the storage means.

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