JP2005159696A - Wireless data transmitting/receiving apparatus for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently transmit information that a person has by oneself among pieces of wireless data transmitting/receiving apparatus mounted on a number of vehicles, and to efficiently receive required information. <P>SOLUTION: The wireless data transmitting/receiving apparatus A for transmission distributes the summary of possessed content (the time, place, or the like of traffic information) and the IP address (summary information) of an own device to a plurality of pieces of wireless data transmitting/receiving apparatus by a radio LAN by broadcasting. The wireless data transmitting/receiving apparatus B at a reception side determines content desired to be acquired in content that is not possessed in the order of priority, or the like for transmitting to a transmission side A by using unicast. After that, requested content is transmitted and received by using the unicast between the transmission and reception sides A, B, while the pieces of wireless data transmitting/receiving apparatus exist in a communicable range each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to transmission and reception of information mounted on a vehicle and held by each other's devices.

For example, vehicles capable of various information processing such as route guidance based on map data have become widespread.
In a vehicle having such an information processing function, various information such as traffic information, map information, route information, video information, and music information is wirelessly transmitted to and from various information transmission apparatuses such as an information distribution center and other vehicles. There are cases where transmission and reception are performed by communication.
When transmitting and receiving data between the information distribution center and other vehicles, data communication is performed by a client / server system that centrally manages data using an in-vehicle phone or a connected mobile phone. It is common.
In addition, as shown in the following Patent Document 1, a method of performing data communication between vehicles by a wireless LAN has also been proposed.
JP 2001-136190 A

In the case of a data communication system using an in-vehicle phone or a mobile phone, there is a problem that the communication cost is high because a method of charging for the amount of packets during data transmission / reception is common.
In addition, in the case where the communication speed is put into practical use, the maximum speed is as low as 384 Kbps, and the communicable area is limited to the usable range of the mobile phone.
Furthermore, server side client-side development and operation costs are required.

On the other hand, the method of Patent Document 1 using a wireless LAN has an advantage that a server development cost and a communication cost are unnecessary.
However, data transmission / reception assumes data transmission / reception between specific vehicles.
For this reason, when data is transmitted and received individually between vehicles, only information to be transmitted and information to be received are transmitted and received, and information owned by any vehicle cannot be obtained.

On the other hand, since vehicles often communicate while traveling, when transmitting and receiving data while traveling, the time during which each vehicle that transmits and receives data is within the data transferable region is often short. .
For this reason, it may frequently occur that transmission / reception of data cannot be completed completely.
In that case, since the received data is incomplete, it becomes necessary to acquire the corresponding data again from another vehicle or the like. At this time, if data transmission / reception cannot be completed again, this is repeated, which is inefficient.

Accordingly, a first object of the present invention is to provide a wireless data transmitting / receiving apparatus capable of efficiently transmitting information held by itself to wireless data transmitting / receiving apparatuses mounted on a large number of vehicles.
It is a second object of the present invention to provide a wireless data transmitting / receiving apparatus capable of efficiently receiving necessary information from information held by an arbitrary vehicle.

According to the first aspect of the present invention, information storage means for storing information, summary creation means for creating a summary of information stored in the information storage means, at least a part of each created summary, and its own device Summary information distribution means for distributing the summary information having the identification information to a plurality of other wireless data transmission / reception devices by wireless communication, a transmission request for information corresponding to the summary specifying the identification information of the own device, Request information receiving means for receiving request information having identification information of the requesting device by wireless communication, and specifying the identification information of the received request information, and transmitting information corresponding to the request information transmission request by wireless communication The information transmission means is provided in the wireless data transmitting / receiving apparatus to achieve the first object.
In the invention according to claim 2, information storage means for storing information, summary information receiving means for receiving summary information of information distributed from another wireless data transmitting / receiving apparatus by wireless communication, and the received summary information , Extracting information that is not stored in the information storage means, and transmitting request information having a transmission request for the information and identification information of the device by wireless communication by specifying the identification information included in the summary information The second object is achieved by providing the wireless data transmitting / receiving apparatus with request information transmitting means and information receiving means for receiving information transmitted in response to a request from the information transmission requesting means.
According to a third aspect of the present invention, in the wireless data transmitting / receiving apparatus according to the first or second aspect, the wireless communication uses a wireless LAN.

According to the first and third aspects of the present invention, the summary information having at least a part of the summary of each information stored in the information storage means and the identification information of the own device is sent to a plurality of other vehicles. The wireless data transmission / reception device installed in the wireless data transmission / reception device is configured to transmit the information corresponding to the transmission request of the received request information by wireless communication. It is possible to efficiently transmit information held by itself.
Further, according to the present invention as set forth in claim 2 and claim 3, a request is made for information not stored in the information storage means from the summary information received from another wireless data transmitting / receiving apparatus, and in response to the request. Since the information to be transmitted is received, the necessary information can be efficiently received from the information held by any vehicle.

  Hereinafter, an embodiment in which a wireless data transmitting / receiving apparatus of the present invention is applied to a vehicle-mounted navigation apparatus will be described with reference to FIGS.

(1) Outline of Embodiment In the present embodiment, the navigation device 20 mounted on each vehicle functions as a wireless data transmitting / receiving device.
Each navigation device 20 transmits / receives various contents such as traffic information, map information, music information, image information, document information, and the like held by data transmission using a wireless LAN.
At that time, each time the wireless data transmitting / receiving apparatus A that performs transmission meets a predetermined time interval or other conditions, the wireless data transmitting / receiving apparatus A automatically summarizes all or a part of the contents held by itself (for example, the time and place of traffic information) and the like. The summary information having the IP address (identification information) of the device is distributed to a plurality of wireless data transmission / reception devices by broadcasting over the wireless LAN. In addition to transmission by broadcast, transmission to the plurality of apparatuses can be performed by multicast transmission or transmission targeting all apparatuses by a wild card address.

As a data receiving side, the wireless data transmitting / receiving apparatus B mounted on a vehicle existing in a wireless LAN communication range has a method for acquiring contents to be acquired from contents received by the apparatus itself, out of contents that the apparatus itself does not have ( In order of preference, priority, etc.).
Then, the wireless data transmitting / receiving apparatus B on the receiving side transmits the request information (the determined content request and the IP address of the own apparatus B) to the transmitting side A by unicast.
Thereafter, the wireless data transmission / reception apparatuses A and B perform transmission / reception unicast of the requested content while they are within the communicable range.
The data transmission / reception functions of the wireless data transmission / reception devices A and B are equivalent, and data can be transmitted from the vehicle B to the vehicle A or a vehicle C equipped with a similar system.

When communication is terminated outside the communicable range during data transmission / reception, the wireless data transmission / reception apparatus B that is receiving associates the received data with a summary with incomplete identification indicating incompleteness. Save it.
If the summary included in the summary information received again (which may be the wireless data transmitting / receiving device A or another device that received a part) matches the summary with incomplete identification, that is, When the summary of the content received only from the other transmission side device D is received, only the data of the unacquired part is requested to the transmission side device D and the remaining data is received.

(2) Details of Embodiment FIG. 1 is a configuration diagram illustrating the configuration of the navigation device 20.
As shown in FIG. 1, the navigation device 20 mainly includes a CPU 21, a memory 22, a data storage 23, an input / output interface 24, an input device 25, a display 26, a GPS sensor 31, a vehicle speed sensor 32, a gyro sensor 33, The wireless communication device 35 includes a speaker (not shown) and the like.

In addition, although the navigation apparatus 20 of this embodiment functions as a radio | wireless data transmission / reception apparatus, you may make it mount a radio | wireless data transmission / reception apparatus independent of a navigation apparatus in a vehicle.
In this case, the navigation device and the wireless data transmission / reception device are configured to operate in cooperation with each other to enable data input / output between them. For example, the navigation device outputs the detected position information and the like to the wireless data transmitting / receiving device based on a request from the wireless data transmitting / receiving device.

The CPU 21 is a central processing unit that controls the navigation device 20, and is connected to a memory 22 (program storage means), a data storage 23 (information storage means), an input / output interface 24, and the like via a system bus.
The memory 22 stores various control programs 22b to 22f in addition to a system program 22a for controlling the CPU 21.
The CPU 21 reads out these programs from the memory 22 as necessary, and executes them sequentially, so that information storage means, summary creation means, summary information distribution means, request information reception means, information transmission means, summary information reception means, information Transmission request means, request information reception means, etc. also function as various function realizing means.
The CPU 21 has a built-in clock 21a having a function of outputting current date / time data. The timepiece 21 can also acquire current date / time data from the GPS sensor 31 when the navigation device and the wireless data transmitting / receiving device are not independent from each other.

The memory 22 is a semiconductor storage device connected to the system bus, and constitutes a main storage space used by the CPU 21.
The memory 22 includes a system program 22a,
An input program 22b, summary creation program 22c, transmission request generation program 22d, route search program 22e, output program 22f, data transmission / reception program 22g, and other various programs are stored.

The input program 22b is a program that enables information input from the input device 25.
The summary creation program 22c is a program for creating a summary of each individual content (information) of the data file.
The transmission request generation program 22d is a program that creates request information from the received summary information (summary + IP address of transmission device).

The route search program 22e is a program that searches for a travel route from a departure point to a destination, which is a basic function of the navigation device 20.
That is, the route search program 22e has a function of searching for a destination input by the input device 25 based on map information stored in a map information database (not shown), a departure point input by the input device 25, or a GPS sensor. This has a function of searching for a recommended route from the current location of the vehicle detected by the vehicle 31 to the desired destination based on road information recorded in the map information database. The route search is performed by, for example, a shortest route search algorithm by the Dijkstra method.

  The output program 22f has a function of displaying route guidance information, transmission setting information of a data file, etc. on the display 26 as a diagram or a character, a function of displaying the contents of received summary information on the display 26, or outputting from a speaker, etc. This program realizes various output functions.

The data transmission / reception program 22g is a program for transmitting / receiving various data such as transmission / reception of summary information, transmission / reception of request information, transmission / reception of requested contents (information) to / from other wireless data transmission / reception devices via a wireless LAN. is there.
Other programs (not shown) include, based on the current position of the vehicle, the travel route searched by the route search program, voice output and image display (display of map information displaying the searched route, display of intersections and traveling directions, etc.) There are route guidance programs etc. that guide by

The data storage 23 constitutes an auxiliary storage space used by the CPU 21.
The data storage 23 is at least one of various storage media such as a hard disk (HD), a compact disk (CD-R / RW), a magneto-optical disk (MO), a digital versatile disk (DVD), and a semiconductor storage device. It is comprised with the storage medium.
The data storage 23 is connected to the CPU 21 via the system bus.

The data storage 23 stores a traffic information file 23a, a music information file 23b, an image information file 23c, a document information file 23d, a summary file 23e, an IP address 23f, and other various data selected as a plurality of data files. .
These data files are stored in advance in the data storage 23, received from the wireless data transmitter / receiver 20 mounted in another vehicle 202, 204, or an information distribution center (not shown). There is what was done.

  The input / output interface 24 is a device that mediates the exchange of data between the input device 25, the display 26, the GPS sensor 31, the vehicle speed sensor 32, the gyro sensor 33, the wireless communication device 35, and the CPU 21 and the like. Connected to the bus.

The input device 25 is an input device provided on the operation panel of the navigation device 20, and is connected to the system bus via the input / output interface 24.
The input device 25 is used to input information related to a destination or the like that the user desires to search for a route through the input program 22b, or to input setting information regarding a data file transmission process.
In general, a configuration in which a predetermined number of push-type switches are arranged is colored, but in consideration of simplification of input operation, a touch panel type provided on the surface of the display 26 or a navigation device that recognizes a user's voice. Some of them are composed of a microphone that converts input information to 20 and a voice recognition device.

The display 26 is a display device that can output the recommended guidance route from the departure point to the destination, transmission setting information of the data file, and the like via the output program 22f, and is provided on the operation panel of the navigation device 20.
The display 26 is also connected to the system bus via the input / output interface 24, and is constituted by, for example, a liquid crystal display or a CRT display. Some display screens include a touch panel constituting the input device 25.

  In this embodiment, the input device 25 and the display 26 are provided on the operation panel of the navigation device 20. However, the present invention is not limited to this, and the input device 25 and the navigation device 20 are provided in a separate housing. The display 26 may be configured. Further, the input device 25 and the display 26 may be physically separated from each other.

  The GPS sensor 31 is for outputting the current position data of the vehicle according to longitude and latitude, and is connected to the system bus via the input / output interface 24. The GPS sensor 31 includes a GPS receiver that receives signals from a plurality of GPS satellites and measures the absolute position of the user.

The vehicle speed sensor 32 and the gyro sensor 33 are for measuring the relative position of the vehicle, and are connected to the system bus via the input / output interface 24.
These sensors are used for autonomous navigation, and the relative position measured by these sensors is the absolute position measured by the GPS receiver, such as in a tunnel where the GPS receiver cannot receive radio waves from the satellite. This is used to correct positioning errors.

The wireless communication device 35 is a wireless LAN communication device for transmitting / receiving data to / from another vehicle 200 or the like through a wireless communication line, and is connected to the system bus via the input / output interface 24.
For example, a wireless LAN communication system based on a spread spectrum communication system is used, and for example, a one-to-n (n is a plurality) communication mode using broadcast or multicast with a radius of 200 m to 1 km as a communicable area is colored. .
As a result, it is possible to effectively “broadcast” content summary information held by the device itself by a plurality of wireless data transmission / reception devices by data file summary creation processing and data transmission / reception processing described later.

  In the wireless LAN communication system using the wireless communication device 35, when request information is transmitted, one-to-one communication is performed by unicast designating an IP address included in the received summary information. In addition, even when the requested information body (content) is transmitted, unicast communication specifying the IP address included in the received request information is performed.

  In addition, the code | symbol ANT shown in FIG. 1 shows the antenna connected to the radio | wireless communication apparatus 35, for example, has employ | adopted the space diversity system.

A transmission / reception method for sharing content among a plurality of navigation devices (wireless data transmission / reception devices) configured in this manner will be described.
FIG. 2 shows a procedure for transmitting / receiving content between the wireless data transmitting / receiving devices mounted on the vehicle A and the vehicle B.
In FIG. 2, a case where content is transmitted from the wireless data transmission / reception device of the vehicle A (hereinafter simply referred to as the vehicle A, hereinafter the same) to the vehicle B will be described as an example. The wireless data transmission / reception devices can be the content transmission side and the content reception side.
Accordingly, all the wireless data transmission / reception devices perform the same operation as the wireless data transmission / reception device of the vehicle A and the same operation as the wireless data transmission / reception device of the vehicle B.

In content transmission / reception in the present embodiment, the CPU 21 of the vehicle A starts from disclosure of content that the own device has and can transmit to another vehicle N (arbitrary vehicle) that exists in a wireless LAN communicable area. Is done.
The CPU 21a of the vehicle A on the content transmission side executes the summary creation program 22b and creates summary information for disclosing the content that can be transmitted (step 101).
That is, the vehicle A acquires a summary for all or a part of content (information) held in the data storage 23 from the summary file 23e, and from this summary and the IP address of the own device stored in the IP address 23f. Create summary information.

  When acquiring a summary of a part of all the contents that are held, among the contents types that are held such as traffic information contents, image (including video) information contents, music information contents, document information contents, advertisement information contents, etc. There are cases where a part (one or more types) of content is acquired, and only content having a predetermined priority order is acquired from all contents regardless of the type of content.

The priority is determined for each individual content, for each content classification (classification without content of the same type) and for each content type, and can be set freely by the user.
For example, in the case of music information content or image information content, the priority set in each information distribution center (wireless data transmission / reception device such as a server placed in a fixed location other than the vehicle) that distributes the content first, And the priority set by the user of the wireless data transmitting / receiving apparatus that acquired the content is used.

  The priority order for each content type is also set. As a default setting, for example, the priority order of traffic information content is the highest, and in the following order: music information content, image information content, document information content, advertisement information content Prioritized. The user can change the priority after each content type.

Traffic information content, music information content, image information content, and some document information content (news display content, etc.) further have intra-class priorities that are valid only within the content type or within the category.
For example, the date and time distributed from each corresponding information distribution center is set as a priority, and the newer content has a higher priority.
In addition to the date and time, it is also possible for the user to set priorities in the order of preference that the user wants to deliver.

  The contents included in each content, such as the priority order such as initial delivery date and time, the priority order set in the information delivery center, and the expiration date of the content used when generating a summary of a part to be delivered Is used.

Note that when a summary of a part of content is determined based on the priority order, information with a low priority order cannot be distributed at all.
Therefore, when determining some summaries, it is possible to change the distribution ratio based on the priority order, instead of always acquiring only the high priority summary. For example, the contents from the first priority to the nth are targeted for distribution every time, and the contents from the n + 1th to the n + pth are targeted for distribution once every three times. Hereinafter, the distribution ratio is changed according to the order.
However, content such as traffic information content or weather information content whose value as information significantly decreases with the passage of time is excluded.

The summary for each content is determined for each information content, with a focus on header information and bibliographic items. For example, the content is as follows.
In the case of traffic information content, it is composed of date and place (or region). It is also possible to add lane information to the summary component.

In the case of music information content, it is composed of a title and a genre (enka, pop, rock, etc.).
In the case of music information content, it is also possible to add a part of actual information, for example, actual music data that can be played for the first t1 seconds, to the summary.

In the case of image information content, it is composed of title, image type (still image, moving image), and genre (in the case of video, drama, Japanese movie, Western image, etc.).
In the case of video information content, a part of the actual information, for example, in the case of a photo book, the first few still images, and in the case of a video, actual moving image data capable of displaying the first t2 seconds of video is added to the summary. It is also possible.

The document information content includes a document name, a classification (news document, novel, etc.), and a genre (history, reasoning, pure literature, etc.).
The advertisement information content includes a title and a genre (food, clothing, movies, music, books, etc.).

The summary is obtained by extracting all or a part of the summary stored in the summary file 23e. The summary itself is stored in the summary file 23e as follows.
That is, the content that the device itself has and the content received from the information distribution center are generated and stored in the summary file 23e when the content is stored in the data storage.

  On the other hand, for the summary about the content received from the summary information distributed from other wireless data transmitting / receiving devices, the summary included in the distributed summary information is stored in the summary file 23e. However, if the delivered summary includes a unique summary set by the delivery side, it is deleted. If there is a unique summary to be set by the receiving device (self device), the unique summary set from the content received by request is added.

When the summary information is created in the transmission-side vehicle A as described above, the CPU 21 of the transmission-side wireless data transmission / reception device A (referring to the wireless data transmission / reception device 20 mounted on the vehicle A) performs the data transmission / reception program 22g. Accordingly, the created summary information is distributed (transmitted) to a plurality of wireless data transmitting / receiving devices existing in a communicable range by broadcasting through the wireless communication device 35 (step 103).
The summary information is transmitted periodically at predetermined time intervals. It should be noted that the summary distribution interval may be lengthened when the regular transmission is performed at normal times and a large number of connection requests are received.

On the other hand, the receiving vehicle B receives the summary information distributed from the vehicle A (step 105), temporarily stores it in the RAM, and executes the transmission request creation program to create request information from the summary (step). 107).
That is, the CPU 21 of the wireless data transmission / reception device B (wireless data transmission / reception device mounted on the vehicle B) compares the summary received from the vehicle A with the summary stored in the summary file 23e of the vehicle B, A summary of content that the device (reception side) does not have is extracted and a transmission request is created.
The transmission request is determined in the order in which the request is made in the order determined based on the new order, the preference order, and the priority order.
Then, request information is created from the created transmission request and the IP address of the own device (receiving side) B read from the IP address 23f.

It should be noted that, even if there is a summary to which incomplete identification described later is added in the summary in the received summary information, the summary is extracted as a transmission request target. In this case, the summary to which the incomplete code is added is the highest priority request order.
In the request display in this case, in addition to the summary of the requested content and the IP address of the receiving-side wireless data transmitting / receiving apparatus B, continuous reception indicating a portion (unreceived data) that should be continuously received in the content X Add location information.

The transmitting side wireless data transmitting / receiving apparatus B transmits the request information as soon as it is created (step 109).
That is, the CPU 21 of the wireless data transmission / reception device B reads the IP address of the wireless data transmission / reception device A that transmitted the summary information from the summary information temporarily stored in the RAM, and specified the IP address via the wireless communication device 35. Request information is transmitted to the wireless data transmitting / receiving apparatus A by unicast.
The request information is transmitted according to the data transmission / reception program 22g.
It should be noted that when the amount of communication by the wireless LAN is large, it is variable such as shifting the timing for transmitting the request information.

  Note that the request information is created and transmitted sequentially in the order of requests for each individual summary. That is, as soon as the content corresponding to the request is received, the next request information is transmitted. However, the request information is created together with the IP address of the own device B by arranging all the summaries of the request targets in the order of requests. Anyway. In this case, the transmitting apparatus A transmits contents in the order of summaries included in the request information.

The request information transmitted from the wireless data transmitter / receiver B is received by the wireless data transmitter / receiver A on the transmitting side, which is the designated IP address (step 110).
The transmitting-side wireless data transmitting / receiving apparatus A that has received the request information reads the content corresponding to the summary that is the request target from the request information from the data storage 23. Then, the read content (information body) is transmitted to the receiving-side wireless data transmitting / receiving apparatus B by unicast designating the IP address included in the received request information.
The content transmission method in this case is, for example, a stream format from the top of the data, a block format divided into an appropriate size, or the like.

  The wireless data transmitting / receiving apparatus on the receiving side receives the content (information body) transmitted from the transmitting side A in response to the request, stores it in the corresponding information file in the data storage 23, and temporarily stores it in the RAM. The summary is stored in the summary file 23e (step 113).

  Thereafter, if there is another content to be requested, request information is created from the summary of the next priority order and the IP address (step 107), and the processing between steps 113 is repeated while communication is possible.

By the way, not only communication between the wireless data transmission / reception devices mounted on the vehicle but also communication between the information distribution center and the wireless data transmission / reception device mounted on the vehicle, when the vehicle equipped with the wireless data transmission / reception device is running In some cases, the communication ends when the user moves out of the communicable area while receiving the content.
That is, when a plurality of contents are sequentially requested from the same transmitting side wireless data transmitting / receiving apparatus A (there may be one request), both vehicles are out of the communicable area while receiving the requested contents. The communication may be terminated.
Processing when communication is terminated during content reception in this way will be described next.

FIG. 3 shows a state in which the remaining content is completely received even when the reception of the content is interrupted in the middle. In FIG. 3, the time is displayed from (a) to (c).
As shown in FIG. 3A, based on the distribution of summary information from vehicle A (car A) having content X first (step 103), own vehicle B transmits request information for content X (step 103). Step 109). Then, the vehicle X receives the content X transmitted from the vehicle A (step 111) based on the request (step 113).

However, as shown in FIG. 3B, it is assumed that communication between the two vehicles is interrupted because both the vehicle A and the vehicle B travel before the reception of the content X is completed.
In this case, the wireless data transmitting / receiving apparatus B on the receiving side stores the received content X ′ in the data storage 23 without discarding the received content X ′.
In addition, the summary for the content X ′ (X) received halfway is also attached with incomplete identification indicating that the reception is in progress and continuous reception location information indicating the location where the content should be continuously received, and the summary file 23e. To store.
The continuous reception location information itself may also be used as incomplete identification.

And since the vehicle C does not hold | maintain the content X as shown in FIG.5 (b), the summary of content X '(X) does not exist in the summary information from the vehicle C. FIG.
Accordingly, the own vehicle B requests and receives the content only when the summary information received from the vehicle C includes a request target other than the content X.

Then, as shown in FIG. 3C, it is assumed that the wireless data transmission / reception device of the vehicle D holds the content X. Then, the summary about the content X is included in the summary information received from the vehicle D.
Therefore, the own vehicle B compares the summaries to which the incomplete use identification is added by comparing the total summaries received with the summaries stored in the summary file 23e. Request information of the content X to be created.
In this case, as described above, the request information is created including the continuous reception location information in addition to the summary and the IP address of the receiving-side wireless data transmitting / receiving apparatus B (step 107).
Then, the own vehicle B transmits the created request information to the vehicle D by unicast (step 109), and receives the rest of the received content X ′ (part of the content X) from the vehicle D (step 113). .
The remaining content X ″ (= XX ′) of the content X is stored in the data storage together with the stored content X ′.
Then, the receiving-side wireless data transmitting / receiving apparatus B deletes the incomplete use identification and the continuous reception location information added to the summary, and completes reception of the content X.

Next, details of processing in which the reception-side wireless data transmission / reception device B receives content from the summary information distributed and received from the transmission-side wireless data transmission / reception device A will be described with reference to the flowchart of FIG.
The processing shown in FIG. 4 is executed by the CPU 21 of the receiving vehicle B by the transmission request creation program 22d and the data transmission / reception program 22g.
The CPU 21 on the receiving side B creates and transmits request information from the received summary information (step 11). This processing corresponds to the processing of steps 105 to 109 described in FIG.

Next, the CPU 21B (the CPU 21 of the receiving vehicle B, the same applies hereinafter) sequentially receives content data transmitted from the transmitting device in response to the request from the wireless communication device 35 (step 13).
Here, in the case of reacquisition of incomplete data, the CPU 21B receives data from the next portion of the acquired data if the stream format is in the data transmission format, and receives the data of the unacquired block if it is the block format. Receive. At this time, the data transmission side transmits data (on the way or in a block) based on the continuous reception location information requested from the data reception side.

Then, the CPU 21B determines whether or not the communication is finished (step 15).
The CPU 21B determines that the communication has ended when the communication is interrupted during the reception of data and when the reception of all the data of the content is completed.

If the communication has not ended, the CPU 21B determines whether or not the received data is new data (step 17). The CPU 21B can determine whether the data is new data, for example, by acquiring the data name at the time of transfer or data information before the transfer.
If the data is new data (step 17; Y), the CPU 21B stores the received data as new content in the corresponding file in the data storage 23 (step 19), and returns to step 13 to continue receiving data.

  On the other hand, when the received data is not new data, that is, when it is the remaining data of the content to which the incomplete use identification is added (step 17; N), the CPU 21B uses the received remaining data (X ″). Append to the already stored data X ′ (step 21), and return to step 13 to continue receiving data.

When communication is completed in step 15 (step 15; Y), the CPU 21B determines whether the requested content has been completely received (step 23).
Whether or not the content has been completely received by the CPU 21B can be determined, for example, by acquiring in advance the data length, checksum, hash value, and the like.
When the content is not completely received, that is, when communication is interrupted in the middle of data reception (step 23; N), the CPU 21B adds the incomplete identification to the continuous reception location information in the summary corresponding to the content being received. Is added (step 25), and the process ends.

On the other hand, when the content is completely received (step 23; Y), the CPU 21B determines whether or not incomplete identification has already been given (step 27).
If the incomplete identification is given (step 27; Y), the CPU 21B deletes the continuous reception location information and the incomplete identification (step 29), and ends the process.
On the other hand, if the incomplete identification is not given (step 27; N), the CPU 21B ends the process as it is.

  In the above processing, the case where the incomplete identification and the addition and deletion of the continuous reception location information are performed on the summary stored in the summary file 23e has been described. However, it is assumed that the database is stored and deleted in association with another database. It may be.

As described above, according to the wireless data transmitting / receiving apparatus of this embodiment, the following effects can be obtained.
(1) According to the present embodiment, since data transmission / reception is performed by a wireless LAN, a wireless data transmission / reception apparatus can be easily realized. Accordingly, the communication cost can be kept low, and the development and operation cost on the server side becomes unnecessary.
(2) Since the summary of the content held by the device itself is distributed by broadcasting using a wireless LAN, it is possible to easily notify the content that can be transmitted to many wireless data transmission / reception devices.
(3) Also, since the summary composed of a part of the content that can be transmitted is distributed before the content itself is transmitted, the content that can be transmitted with a small amount of data can be easily notified.

(4) Further, when communication is interrupted in the middle of content reception, instead of re-receiving from the beginning, only the content of the unacquired portion is received by holding the already received content. As a result, the time required for re-acquisition of content can be shortened.
In addition, in a wireless data transmission / reception device mounted on a vehicle, content that is surely desired even when communication time can be secured only for a relatively short time by moving the transmission side and reception side to a communicable range by wireless LAN. Can be obtained.

The preferred embodiments of the wireless data transmitting / receiving apparatus of the present invention have been described above. However, the present invention is not limited to the described embodiments, and various modifications can be made within the scope described in each claim. It is.
For example, in the embodiment described above, when there are a plurality of wireless data transmission / reception devices capable of transmitting request information, a case has been described where the summary information is received from the wireless data transmission / reception device that received the summary information first. You may make it select.
That is, when transmitting the request information, it is advantageous to transmit the request information to a wireless data transmission / reception apparatus that can secure a communication time as long as possible.

Therefore, when transmitting request information, it is possible to determine the priority order of wireless data transmitting / receiving apparatuses that can transmit in the following order. (1) is the highest and (4) is the lowest.
(1) Wireless data transmission / reception device for a vehicle traveling in the same direction as the traveling direction of the host vehicle (2) Wireless data transmission / reception device for an information distribution center (does not move)
(3) Wireless data transmission / reception device for a vehicle traveling on a road that intersects the road on which the host vehicle is traveling (4) Wireless data transmission / reception device for a vehicle traveling in a direction opposite to the traveling direction of the host vehicle

In addition, when there are a plurality of wireless data transmission / reception devices having the same priority, it is determined by the distance from the vehicle position.
That is, in the case of the data transmission / reception device of (1), the higher priority is set as the distance from the own vehicle is shorter.
In the case of the wireless data transmitting / receiving apparatuses (3) and (4), the higher the priority is, the longer the distance from the own vehicle is.

In the above case, the wireless data transmitting / receiving device on the transmission side adds the current position of the vehicle and travel direction data indicating the travel direction such as route data to the summary information.
On the other hand, the wireless data transmission / reception device on the receiving side determines the priority order from the received summary information, the current position and the traveling direction of the own vehicle, and transmits request information to the wireless data transmission / reception device with the highest priority order. .

Therefore, in the wireless data transmitting / receiving apparatus according to the present modification, a current position acquisition unit that acquires the current position of the vehicle and a traveling direction identification unit that identifies the traveling direction of the vehicle are essential.
However, in the case of an information distribution center that does not move, the traveling direction acquisition means is unnecessary. The current position acquisition means of the information distribution center stores the current position measured in advance in the storage means, and acquires the current position by reading the current position therefrom.

The current position acquisition means is realized by the CPU 21 calculating the current position from the detection values of at least one of the vehicle speed sensor 32, the gyro sensor 33, and the GPS sensor 31.
Further, the traveling direction specifying means is realized by determining the traveling direction from a plurality of current position data calculated by the CPU 21. In addition, when determining a running direction, you may make it use road data further.

  Thus, according to this modification, when there are a plurality of wireless data transmission / reception devices that can transmit request information, the wireless data transmission / reception device with higher priority is more likely to secure a longer communication time. Increasing the reception of the requested content without interrupting communication on the way increases the content reception efficiency.

1 is a configuration diagram of a vehicle-mounted navigation device to which a wireless data transmitting / receiving device of the present invention is applied. It is explanatory drawing showing the procedure which transmits / receives content between the radio | wireless data transmission / reception apparatuses mounted in the vehicle of a transmission side, and the vehicle of a reception side. It is explanatory drawing also showing a mode that the remaining content is completely received when reception of content is interrupted on the way. It is a flowchart showing the process in which the receiving-side wireless data transmitting / receiving device receives content from the summary information distributed and received from the transmitting-side wireless data transmitting / receiving device or the like.

Explanation of symbols

20 Navigation device 21 CPU
22 memory 22c summary creation program 22d transmission request generation program 22g data transmission / reception program 23 data storage 23a traffic information file (multiple files)
23b Music information file (multiple files)
23c Image information file (multiple files)
23d Document information file (multiple files)
23e Summary file (multiple files)
23f IP address 31 GPS sensor 32 Vehicle speed sensor 33 Gyro sensor 35 Wireless communication device

Claims (3)

Information storage means for storing information;
Summary creating means for creating a summary of each information stored in the information storage means;
Summary information distribution means for distributing summary information including at least a part of the created summary and identification information of the device to a plurality of other wireless data transmission / reception devices by wireless communication;
Request information receiving means for receiving by wireless communication request information having identification information of its own device, requesting transmission of information corresponding to the summary, and identification information of the requesting device;
Information transmitting means for specifying identification information of the received request information and transmitting information corresponding to the transmission request of the request information by wireless communication;
A wireless data transmitting / receiving apparatus comprising: Information storage means for storing information;
Summary information receiving means for receiving summary information of information distributed from another wireless data transmitting / receiving device by wireless communication;
Information not stored in the information storage means is extracted from the received summary information, and request information having a transmission request for the information and identification information of the own device is designated as identification information included in the summary information. Request information transmitting means for transmitting by wireless communication,
Information receiving means for receiving information transmitted in response to a request by the information transmission requesting means;
A wireless data transmitting / receiving apparatus comprising: The wireless data transmission / reception apparatus according to claim 1, wherein the wireless communication uses a wireless LAN.

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