JP2010011414A - Radio device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the probability of collisions of packet signals, in inter-vehicle communication. <P>SOLUTION: A position information acquisition section 20 acquires the existence position of an object. A storage section 22 stores map data 50 and additional information 52. The additional information 52 contains area information at a position, where each of a plurality of areas is set, and timing information on timing and period, enabling transmission of signals within a prescribed period in each area. An area deciding section 58 locates an area including an existence position, while referring to the area information. A timing decision section 60 identifies the timing and period, enabling transmission of signals to the located area, while referring to the timing information. A radio communication section 30 transmits signals with an identified timing and period. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to wireless technology, and more particularly, to a wireless device that transmits a signal based on a common location.

Road-to-vehicle communication is being studied to prevent collisions at intersections. In the road-to-vehicle communication, information on the situation of the intersection is communicated between the roadside device and the vehicle-mounted device. Road-to-vehicle communication requires the installation of roadside equipment, which increases labor and cost. On the other hand, if it is a form which communicates information between vehicles, ie, onboard equipment, installation of a roadside machine will become unnecessary. In that case, for example, the current position information is detected in real time by GPS (Global Positioning System), etc., and the position information is exchanged between the vehicle-mounted devices so that the own vehicle and the other vehicle respectively enter the intersection. (See, for example, Patent Document 1).
JP 2005-202913 A

  In a wireless LAN (Local Area Network) compliant with a standard such as IEEE 802.11, an access control function called CSMA / CA (Carrier Sense Multiple Access Collision Aviation) is used. Therefore, in the wireless LAN, the same wireless channel is shared by a plurality of terminal devices. In such CSMA / CA, due to the distance between terminal devices and the influence of obstacles that attenuate radio waves, a situation occurs in which radio signals do not reach each other, that is, a situation where carrier sense does not function.

  This situation is also called the “hidden terminal” problem. On the other hand, when such CSMA / CA is applied to inter-vehicle communication, a hidden terminal problem occurs due to the presence of a building or the like at an intersection. Furthermore, since the number of vehicles tends to increase at the intersection, the frequency of packet signal collision due to the hidden terminal problem increases. As a result, retransmission of packet signals occurs frequently, leading to a reduction in information transfer capability, that is, throughput.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a technique for reducing the collision probability of packet signals in inter-vehicle communication.

  In order to solve the above-described problem, a wireless device according to an aspect of the present invention includes a position information acquisition unit that acquires an existing position of an object, area information about a position where each of a plurality of areas is set, and each area. A storage unit that stores timing information regarding a timing at which a signal can be transmitted within a predetermined period and a period, and an area that includes the presence position acquired by the position information acquisition unit while referring to the area information stored in the storage unit While identifying and referring to the timing information stored in the storage unit, the identifying unit that identifies the timing and period in which the signal can be transmitted to the identified area, and the timing and period identified in the identifying unit And a communication unit for transmitting.

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

  ADVANTAGE OF THE INVENTION According to this invention, the collision probability of a packet signal can be reduced in vehicle-to-vehicle communication.

  Before describing the present invention in detail, an outline will be described. Embodiments of the present invention relate to a navigation device mounted on a vehicle. The navigation device stores map data, derives a route to a destination in response to a request from the driver, and displays map data on which the derived route is superimposed on a monitor. In addition, the navigation device has a wireless communication function and executes vehicle-to-vehicle communication. For example, the navigation device transmits an image generated by an imaging device mounted on a vehicle to another vehicle, receives an image from another device, and displays this on a monitor. Here, the wireless communication uses the above-described CSMA / CA, and a hidden terminal problem is likely to occur particularly at an intersection or the like. Therefore, in order to reduce the collision probability of the packet signal in the inter-vehicle communication, the navigation device according to the present embodiment executes the following process.

  The map data stored in the navigation device includes additional information. For example, in the additional information, a lane at each intersection is indicated as an area. At the intersection where two roads intersect, four areas are included. Furthermore, information (hereinafter referred to as “timing information”) that associates each period (hereinafter referred to as “slot”) with a predetermined period (hereinafter referred to as “frame”) and an area is also included in the additional information. ing. Here, the timing information includes the order of assigning slots in the cycle to the area and the period of each slot. The navigation device acquires the current location by GPS and also acquires the traveling direction, and identifies the current area while referring to the additional information.

  In addition, the navigation device acquires the slot start timing and the slot period corresponding to the specified area. Furthermore, the navigation device generates a frame so as to be synchronized with a signal from a GPS satellite. By reflecting the start timing of the slot and the period of the slot in the generated frame, the navigation apparatus determines the slot allocated to itself. The navigation device transmits a packet signal using the CSMA / CA in the determined slot. On the other hand, the navigation device receives a packet signal transmitted from another vehicle regardless of the determined slot.

  FIG. 1 shows a road situation according to an embodiment of the present invention. This corresponds to a case where one intersection is viewed from above. As shown in the drawing, the road that goes in the horizontal direction of the drawing, that is, the left and right direction, intersects the vertical direction of the drawing, that is, the road that goes in the up and down direction, at the center. The intersection of the two roads is an “intersection”. The first vehicle 10a, the second vehicle 10b, and the third vehicle 10c are traveling from left to right, and the fourth vehicle 10d and the fifth vehicle 10e are traveling from right to left. Further, the sixth vehicle 10f, the seventh vehicle 10g, and the eighth vehicle 10h are traveling from the bottom to the top, and the ninth vehicle 10i, the tenth vehicle 10j, and the eleventh vehicle 10k are directed from the top to the bottom. Progressing.

  Each of the plurality of vehicles 10 has a wireless communication function and an imaging function (not shown). For example, each vehicle 10 captures an image near an intersection and exchanges it with another vehicle 10 through wireless communication. As a result, the driver can confirm the state of the road near the intersection by confirming the image captured by the other vehicle 10. Here, the wireless communication system corresponds to, for example, CSMA / CA. Note that information exchanged between the vehicles 10 is not limited to images, but for ease of explanation, image exchange will be described below.

  FIG. 2 shows a configuration of the navigation apparatus 100 according to the embodiment of the present invention. The navigation device 100 includes a position information acquisition unit 20, a storage unit 22, a specification unit 24, a synchronization unit 26, a communication control unit 28, a wireless communication unit 30, an antenna 32, a processing unit 34, an IF unit 36, an operation unit 38, and an imaging unit. 40, a monitor 42, a speaker 44, an apparatus control unit 46, and an image processing unit 48. The storage unit 22 includes map data 50 and additional information 52, the specifying unit 24 includes an area determining unit 58 and a timing determining unit 60, and the processing unit 34 includes a route searching unit 54 and a combining unit 56.

  The position information acquisition unit 20 includes a GPS receiver (not shown), a gyroscope, a vehicle speed sensor, and the like, and the presence position of the vehicle 10 (not shown), that is, the vehicle 10 on which the navigation device 100 is mounted, by data supplied from them. To get. Further, the traveling direction and the moving speed are also detected. The position information acquisition unit 20 detects a clock signal having a 1 sec cycle based on a received signal from a GPS satellite. The clock signal is a signal for notifying the timing of a 1 sec cycle. Note that a known technique may be used for the detection of the clock signal, and the description thereof is omitted here. The storage unit 22 is a storage medium that stores map data 50 as electronic information. Here, the map data 50 is defined to include the existing position acquired by the position information acquisition unit 20.

  The map data 50 is formed by vector format data. In the vector format data, a node on the road network representation is defined as a “node”, and a line connecting the nodes on the road network representation. Minutes, or roads, are defined as “links”. At that time, for example, the node is associated with latitude and longitude. In addition, attributes of specific sections and positions in the link are defined as “in-link attributes”. The attribute includes, for example, crossing data. Further, the in-link attribute includes an identification number for identifying a node (hereinafter referred to as “node ID”) and lane information, for example, an identification number for identifying a lane (hereinafter referred to as “lane ID”). Including. Here, a lane number is included for each direction of the road. Therefore, one lane number is assigned to a one-way road, but two lane numbers are assigned to a road that is allowed to pass in both directions.

  Further, the storage unit 22 stores additional information 52 so as to be added to the map data 50. The additional information 52 includes area information specified by a combination of the node ID and the lane ID, and timing information regarding a slot and a slot period in which signals can be transmitted from the wireless communication unit 30 within the frame in each area. The area information can be said to be information for specifying a position where each of a plurality of areas set on the map is set.

  FIG. 3 shows the data structure of the additional information 52 stored in the storage unit 22. The additional information 52 includes a node ID column 200, a division number column 202, an interval column 204, a first slot column 206, a second slot column 208, a third slot column 210, a fourth slot column 212, and an Nth slot column 214. included. In the node ID column 200, node IDs are shown, and each node ID corresponds to an intersection. The division number column 202 corresponds to the number of lanes included in each intersection, which can be said to be the number of lane IDs included in each node ID. The interval column 204 will be described later. The first slot column 206 to the Nth slot column 214 are information on each slot. The number of slots used in each node is the same as the number of divisions in the division number column 202.

  For example, if the division number in the division number column 202 is “4”, the first slot to the fourth slot are used. In one frame, slots are arranged in order from the first slot to the Nth slot. That is, the smaller the slot number, the more forward the frame is. Each of the first slot column 206 to the Nth slot column 214 includes a lane ID and a distribution. The combination of the lane ID and the node ID is the area information described above, and the assigned slot is specified based on these. The distribution indicates the ratio of slots occupied in one frame. For example, if the distribution is “25%”, 25% of one frame corresponds to the slot occupation period.

  FIG. 4 shows an outline of the lane ID. FIG. 4 is shown similarly to FIG. Here, the first lane 110 is a lane that goes from left to right, the second lane 112 is a lane that goes from right to left, the third lane 114 is a lane that goes from bottom to top, A lane 116 is a lane that goes from top to bottom. Further, the first lane 110 to the fourth lane 116 correspond to the lane IDs in FIG. In this way, each lane is defined to cross an intersection.

  FIG. 5 shows an outline of the slot. As shown in the figure, one frame is defined over a period of 100 msec. Further, the frames are repeatedly arranged. Here, it is assumed that four slots are included in one frame and the period of each slot is 25 msec, that is, occupies a period of 25% in the frame. A first slot is arranged at the head of one frame, and a second slot is arranged following this. Furthermore, a fourth slot is arranged at the end of one frame. An interval of “5 msec” is arranged at the last part of each slot. The interval is a period during which no signal is transmitted, and corresponds to a guard time. The interval period is common to each slot, and its value is shown in the interval column 204 of FIG. The unit of the interval column 204 is msec. Returning to FIG.

  The operation unit 38 is an interface that receives an instruction from the driver, and includes buttons and the like. For example, the operation unit 38 receives an instruction for starting a navigation function, searching for a route, and the like (hereinafter, also referred to as “instruction regarding the navigation function”) from the driver. The operation unit 38 outputs the received instruction to the IF unit 36. The imaging unit 40 is installed in front of or behind the vehicle 10 (not shown) and captures an image. Here, it is assumed that it is installed in front of the vehicle 10. The imaging unit 40 converts the captured image into a digital signal and then outputs the digital signal to the IF unit 36. Hereinafter, an image converted into a digital signal or an image itself is referred to as an “image” without being distinguished.

  The monitor 42 displays predetermined information to be notified to the driver in response to an input from the IF unit 36. When the navigation function is being executed, the monitor 42 displays the map data 50 stored in the storage unit 22. The monitor 42 also displays an image for prompting the driver to input an instruction to the operation unit 38. Since such display is a known technique, description thereof is omitted. Further, as described later, the monitor 42 displays an image when the navigation device 100 receives an image from the navigation device 100 mounted on another vehicle. The speaker 44 outputs a sound to be notified to the driver in response to an input from the IF unit 36.

  The IF unit 36 controls data input / output with respect to the operation unit 38, the imaging unit 40, the monitor 42, and the speaker 44. The IF unit 36 receives an instruction regarding the navigation function from the operation unit 38, and outputs the received instruction to the processing unit 34. The IF unit 36 receives a response to the instruction from the processing unit 34 and outputs the response to the monitor 42 and the speaker 44. Furthermore, the IF unit 36 receives an image from the imaging unit 40, outputs the received image to the wireless communication unit 30 via the image processing unit 48, and also outputs an image from the wireless communication unit 30 via the image processing unit 48. Then, the received image is output to the monitor 42.

  The processing unit 34 receives an instruction from the operation unit 38 via the IF unit 36, and executes a navigation function in accordance with the received instruction. The route search unit 54 receives the location of the vehicle 10 detected by the position information acquisition unit 20 and also receives a destination instruction from the operation unit 38 via the IF unit 36. The route search unit 54 reads the map data 50 stored in the storage unit 22 and searches for a route from the current location to the destination while referring to the map data 50. At that time, the route search unit 54 associates the existing position acquired in the position information acquisition unit 20 with the map data 50 stored in the storage unit 22. Moreover, since a well-known technique should just be used for the search of a route, description is abbreviate | omitted here. The route search unit 54 outputs the search result to the synthesis unit 56.

  The combining unit 56 combines the map data 50 and the search result. That is, the composition unit 56 generates map data 50 (hereinafter referred to as “map data 50”) on which the route is superimposed by overlapping the route on the map data 50. The combining unit 56 outputs the generated map data 50 to the IF unit 36, and the IF unit 36 outputs the map data 50 to the monitor 42. The monitor 42 displays the map data 50. On the other hand, the route search unit 54 outputs the search result to the speaker 44 via the IF unit 36 and causes the speaker 44 to output the search result as sound.

  The area determination unit 58 receives the presence position and the traveling direction from the position information acquisition unit 20, and receives the map data 50 and the additional information 52 from the storage unit 22. The area determination unit 58 specifies an area including the presence position while referring to the area information included in the map data 50 and the additional information 52. More specifically, the area determination unit 58 derives latitude and longitude (hereinafter referred to as “expected value”) from the existence position and the traveling direction. Here, the predicted value may be defined to have a predetermined range. In addition, since the node ID, the latitude, and the longitude are associated with each other in the map data 50, the area determination unit 58 selects the node with the latitude and longitude that is closest to the predicted value.

  The area determination unit 58 specifies the node ID for the selected node. As a result, the area determination unit 58 selects one node ID from the node ID column 200 in FIG. That is, the area determination unit 58 selects the closest node ID from the node ID column 200 in FIG. 3 based on the presence position and the traveling direction. Following this, the area determination unit 58 selects a lane ID corresponding to the traveling direction among a plurality of lane IDs corresponding to the selected node ID. As a result, a combination of node ID and lane ID is selected. The area determination unit 58 outputs the selected combination to the timing determination unit 60.

  Based on the combination received from the area determining unit 58, the timing determining unit 60 refers to the timing information included in the additional information 52 and specifies the start timing and period of the usable slot. That is, the timing determination unit 60 specifies a slot based on the node ID and the lane ID included in the combination. For example, in FIG. 3, when the node ID is “A” and the lane ID is “3”, the timing determination unit 60 specifies the third slot and specifies the allocation of 25% of the third slot. The timing determination unit 60 may temporarily store the specified value. Further, the timing determination unit 60 derives the start timing of the third slot by integrating the distribution of slots arranged before the identified slot.

  In the above example, since the distribution of the first slot and the second slot is 25%, the integration result is 50%. Therefore, the timing of 50 msec from the beginning of the 100 msec frame is the start timing of the third slot. Next, the timing determination unit 60 derives the period of the slot from the identified slot distribution. In the above example, since the distribution of the third slot is 25%, 25 msec of the 100 msec frame is the period of the third slot. Furthermore, the timing determination unit 60 also sets an interval. The timing determination unit 60 outputs the slot start timing and period to the communication control unit 28.

  The synchronization unit 26 receives a clock signal from the position information acquisition unit 20. As described above, since the clock signal is a signal for notifying the timing of the 1 sec cycle, the synchronization unit 26 divides the clock signal into 10 to generate the timing of the 100 msec cycle. The head timing of 100 msec (hereinafter simply referred to as “head timing”) corresponds to the head timing of the above-described frame. The synchronization unit 26 outputs the head timing to the communication control unit 28.

  The communication control unit 28 generates continuous frames based on the start timing from the synchronization unit 26. Moreover, the slot to which the navigation device 100 is assigned is generated by reflecting the start timing and period of the slot from the timing determination unit 60 on the frame. The communication control unit 28 instructs the wireless communication unit 30 about the generated slot as a period during which a signal can be transmitted.

  The wireless communication unit 30 executes a wireless communication function corresponding to a communication system in which CSMA / CA is used. Here, the radio communication unit 30 performs signal transmission by CSMA / CA in the slot designated by the communication control unit 28. Below, the transmission process in the radio | wireless communication part 30 is demonstrated first. When the wireless communication unit 30 receives an image from the IF unit 36 via the image processing unit 48, the wireless communication unit 30 includes the image in the packet signal. When the image size is larger than the packet signal size, the wireless communication unit 30 generates a plurality of packet signals by dividing the image into a plurality of images. In addition, when the wireless communication unit 30 receives an instruction regarding a transmittable slot from the communication control unit 28, the wireless communication unit 30 transmits a packet signal from the antenna 32 if transmission is possible by performing carrier sense in the period of the slot. At this time, the packet signal is modulated and the like is not described here.

  Next, reception processing in the wireless communication unit 30 will be described. The wireless communication unit 30 receives a packet signal via the antenna 32. The packet signal is received regardless of the transmittable slot. The wireless communication unit 30 demodulates the packet signal and extracts an image from the demodulated packet signal. The said image is an image imaged with the navigation apparatus 100 with which the other vehicle 10 which is not shown in figure was equipped. The wireless communication unit 30 outputs the image to the IF unit 36 via the image processing unit 48.

  The image processing unit 48 performs a predetermined process on the image used for communication in the wireless communication unit 30. In the transmission process, the image processing unit 48 performs image encoding. In the reception process, the image processing unit 48 performs image decoding and image drawing. Since known techniques may be used for these, description thereof is omitted here. The device control unit 46 controls the timing of the entire navigation device 100.

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

  The operation of the navigation device 100 configured as above will be described. FIG. 6 is a flowchart showing a slot number and allocation distribution acquisition procedure by the navigation apparatus 100. The position information acquisition unit 20 acquires the current position and the traveling direction (S10). The area determination unit 58 acquires a node ID and a lane ID (S12). If there is a change in the node ID and lane ID (N in S14), the timing determination unit 60 acquires the slot number and the allocation distribution (S16). The timing determination unit 60 stores the slot number and the allocation distribution (S18). On the other hand, if there is no change in the node ID and the lane ID (Y in S14), the process is terminated.

  FIG. 7 is a flowchart showing a data transmission procedure by the navigation device 100. The timing determination unit 60 reads the slot number and the allocation distribution (S30). The timing determination unit 60 derives a transmission start time (S32) and derives a transmission permission period (S34). If the current transmission is not possible (N in S36), the wireless communication unit 30 stands by. On the other hand, if transmission is currently possible (Y in S36), the wireless communication unit 30 transmits data (S38).

  Next, a modified example will be described. In the embodiment, slots are assigned according to the existing area. The period of each slot is determined in advance. On the other hand, the number of vehicles 10 present on the road varies even during the day. At that time, a lane in which many vehicles 10 exist and a lane in which there are few vehicles 10 are interchanged with time. The variation takes into account such variations. The navigation device 100 according to the modification corresponds to a VICS (Vehicle Information and Communication System), and acquires information on a traffic jam area and lane (hereinafter referred to as “car traffic information”). The navigation device 100 changes the distribution included in the additional information 52 based on the traffic jam information.

  The navigation device 100 according to the modification is of the same type as the embodiment. Therefore, here, different points will be mainly described. The location information acquisition unit 20 has a VICS function in addition to the functions described above. VICS is a system that displays traffic jam information received from FM multiplex broadcasting or a transmitter on a road in graphics and characters. The traffic jam information is edited and processed by a VICS center (not shown). Such traffic information can be said to be traffic information for an area set in the map data 50 stored in the storage unit 22. The position information acquisition unit 20 outputs the traffic jam information to the specifying unit 24.

  The timing determination unit 60 receives the traffic jam information from the position information acquisition unit 20 and corrects the distribution of the additional information 52 based on the received traffic jam information. Here, the allocation to the traffic lane ID that is congested is increased by a predetermined value, and the allocation to the ID that is not congested is decreased by a predetermined value. Here, the predetermined value may be determined in advance or may be changed according to the degree of traffic jam. In the latter case, the predetermined value increases as the degree of traffic congestion increases. For example, when the predetermined value is predetermined as 10% and the node ID “A” and the lane ID “3” are congested in FIG. 3, the timing determination unit 60 sets the lane ID “3”. Increase distribution to 35%. Also, if the lane ID “4” is not congested, the timing determination unit 60 reduces the allocation for the lane ID “4” to 15%.

  As a result, the slot period is changed so that the period of the third slot is 35 msec and the period of the fourth slot is 15 msec. On the other hand, the start timing of the slot is changed so that the start timing of the fourth slot is 85 msec from the beginning of the frame. Subsequent processing of the timing determination unit 60, the communication control unit 28, and the wireless communication unit 30 is as described above. Note that the timing determination unit 60 may reflect the above change in the additional information 52. On the other hand, after correcting the slot start timing and the slot period, the timing determination unit 60 restores these when a predetermined period elapses. Note that the timing determination unit 60 may restore the slot start timing and the slot period based on the traffic jam information.

  FIG. 8 is a flowchart showing a procedure for changing the transmission start time and the transmission permission period in the navigation device 100 according to the modification of the present invention. The position information acquisition unit 20 acquires traffic jam information (S50). If there is a lane ID that is congested in the current node ID (Y in S52), the timing determination unit 60 changes the transmission start time and the transmission permission period for each lane ID (S54). If there is no traffic jam ID in the current node ID (N in S52), the process is terminated.

  FIG. 9 is a flowchart showing a procedure for returning the transmission start time and the transmission permission period changed in the navigation device 100 according to the modification of the present invention. The timing determination unit 60 recognizes that a certain period has elapsed since the transmission start time and the transmission permission period were changed (S70). If the traffic jam does not continue (N in S72), the timing determination unit 60 returns the transmission start time and the transmission permission period to the original (S74). On the other hand, if the traffic jam continues (Y in S72), step 74 is skipped and the process is terminated.

  According to the embodiment of the present invention, the map data includes a combination of a node ID and a lane ID, and information about a slot and a slot period in which a signal can be transmitted in a frame in each combination. Information can be used for packet signals in vehicle-to-vehicle communication. Also, based on the acquired location, the slot in which signals can be transmitted and the period of the slot are specified, and CSMA / CA is executed in the specified slot, so CSMA / CA is executed between navigation devices that are close to each other. it can. Further, since CSMA / CA is executed between navigation devices that are close to each other to some extent, it is possible to reduce the existence probability of hidden terminals. Moreover, since the existence probability of the hidden terminal is reduced, the occurrence of the hidden terminal problem can be reduced. In addition, since the occurrence of the hidden terminal problem is reduced, the packet signal collision probability can be reduced. Further, since the collision probability of packet signals is reduced, transmission efficiency can be improved.

  Further, since the allocation distribution is changed according to the traffic jam information, the slot period can be increased even if the number of navigation devices is increased. Also, even if the number of navigation devices increases, the slot period is increased, so that an increase in the collision probability of packet signals can be suppressed. In addition, if the predetermined period elapses after the timing information is corrected, the timing information is restored to the original state, so that it is possible to maintain consistency with the settings in other navigation devices. In addition, after the timing information is corrected, the timing information is restored when a predetermined period elapses, so that the processing can be simplified.

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

  In the embodiment of the present invention, the position information acquisition unit 20 acquires the current location by using GPS or the like. However, the present invention is not limited to this. For example, the position information acquisition unit 20 is compatible with a mobile phone system and the like, and may acquire the current location based on the connected base station device. Specifically, the location information acquisition unit 20 receives the identification number of the base station device from the connected base station device. Further, the identification number of the base station device is also associated with the map data 50 stored in the storage unit 22. The position information acquisition unit 20 acquires a presence value from the map data 50 based on the received identification number. The base station apparatus may have a plurality of identification numbers. In this case, the existence position may be derived based on a principle such as three-point measurement. According to this modification, the presence position can be acquired by various processes.

  In the embodiment of the present invention, in the map data 50 and the additional information 52, a plurality of lane IDs are defined for one node ID, that is, one intersection. However, the present invention is not limited thereto. For example, in the map data 50 and the additional information 52, a common lane ID may be defined over a plurality of node IDs. That is, the lane ID “1” is assigned to the same lane in the node ID “A” and the node ID “B”. According to this modification, when the distance between a plurality of intersections is short, the slot can be made common. In addition, since the slots are common, the slots can be allocated efficiently.

The features of the invention described in the embodiments may be defined by the following items.
(Item 1)
A location information acquisition unit for acquiring the location of the object;
A storage unit for storing map data including the existing position acquired by the position information acquisition unit;
A processing unit for associating the existing position acquired in the position information acquisition unit on the map data stored in the storage unit;
In the map data stored in the storage unit, area information for specifying a set position for each of a plurality of areas set on the map, and a signal can be transmitted from the wireless device within a predetermined period in each area A navigation apparatus, to which timing information regarding timing and a period is added.

(Item 2)
A traffic jam information acquisition unit for acquiring traffic jam information for an area set in the map data stored in the storage unit;
The navigation device according to item 1, further comprising a correction unit that corrects the timing information stored in the storage unit based on the traffic jam information acquired by the traffic jam information acquisition unit.
(Item 3)
3. The navigation device according to item 2, wherein the correction unit returns the timing information when a predetermined period has elapsed after correcting the timing information.

It is a figure which shows the road condition which concerns on the Example of this invention. It is a figure which shows the structure of the navigation apparatus which concerns on the Example of this invention. It is a figure which shows the data structure of the additional information memorize | stored in the memory | storage part of FIG. It is a figure which shows the outline | summary of lane ID of FIG. It is a figure which shows the outline | summary of the slot of FIG. 3 is a flowchart showing a slot number and allocation distribution acquisition procedure by the navigation apparatus of FIG. 2. It is a flowchart which shows the transmission procedure of the data by the navigation apparatus of FIG. It is a flowchart which shows the change procedure of the transmission start time in the navigation apparatus which concerns on the modification of this invention, and a transmission permission period. It is a flowchart which shows the procedure which returns the transmission start time and transmission permission period which were changed in the navigation apparatus which concerns on the modification of this invention.

Explanation of symbols

  10 vehicle, 20 position information acquisition unit, 22 storage unit, 24 identification unit, 26 synchronization unit, 28 communication control unit, 30 wireless communication unit, 32 antenna, 34 processing unit, 36 IF unit, 38 operation unit, 40 imaging unit, 42 monitors, 44 speakers, 46 device control units, 50 map data, 52 additional information, 54 route search units, 56 combining units, 58 area determining units, 60 timing determining units, 100 navigation devices.

Claims (3)

A location information acquisition unit for acquiring the location of the object;
A storage unit that stores area information regarding a position where each of the plurality of areas is set, and timing information regarding a timing and a period in which a signal can be transmitted within a predetermined period in each area;
While referring to the area information stored in the storage unit, the area including the existing position acquired in the position information acquisition unit is specified, and with respect to the specified area while referring to the timing information stored in the storage unit A specific unit for identifying a timing and a period during which a signal can be transmitted;
A communication unit that transmits a signal at the timing and period specified in the specifying unit;
A wireless device comprising: It further includes a traffic information acquisition unit that acquires traffic information for the area,
The wireless device according to claim 1, wherein the specifying unit corrects the specified timing and period based on the traffic jam information acquired by the traffic jam information acquiring unit.   The wireless device according to claim 2, wherein the specifying unit restores the timing information when a predetermined period elapses after correcting the timing information.

Images