WO2013094187A1

WO2013094187A1 - Wireless apparatus

Info

Publication number: WO2013094187A1
Application number: PCT/JP2012/008090
Authority: WO
Inventors: 哲一江見; 真琴永井; 児島　則章
Original assignee: 三洋電機株式会社
Priority date: 2011-12-21
Filing date: 2012-12-19
Publication date: 2013-06-27

Abstract

A transmission processing unit (82) executes transmission processing, and a reception processing unit (84) executes reception processing. An estimating unit (86) estimates whether a portable terminal apparatus (14a) is inside of a vehicle or outside of the vehicle. In the cases where the estimating unit (86) estimates that the portable terminal apparatus (14a) is inside of the vehicle, the transmission processing unit (82) transmits signals with transmission power lower than transmission power with which the signals are transmitted in the cases where the portable terminal apparatus is outside of the vehicle.

Description

Wireless device

The present invention relates to communication technology, and more particularly, to a wireless device that transmits and receives a signal including predetermined information.

路 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 the form which communicates information between vehicle-to-vehicle communication, ie, onboard equipment, installation of a roadside machine will become unnecessary. In this 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 each enter the intersection. (See, for example, Patent Document 1).

JP 2005-202913 A

Since various communication environments are assumed when performing road-to-vehicle communication or vehicle-to-vehicle communication, it is desirable to execute communication processing according to the communication environment.

The present invention has been made in view of such circumstances, and an object thereof is to provide a wireless device suitable for a communication environment.

In order to solve the above problems, a wireless device according to an aspect of the present invention is a wireless device that performs communication with another wireless device, and includes a communication unit that performs transmission processing and reception processing, and the wireless device includes: An estimation unit that estimates whether the vehicle exists inside the vehicle or outside the vehicle. When the estimation unit estimates that the wireless device is present in the vehicle, the communication unit transmits a signal with lower transmission power than when the wireless device exists outside the vehicle.

It should be noted that an arbitrary combination of the above-described components 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.

According to the present invention, a wireless device suitable for a communication environment can be provided.

It is a figure which shows the structure of the communication system which concerns on the Example of this invention. It is a figure which shows the structure of the base station apparatus of FIG. FIGS. 3A to 3D are diagrams showing frame formats defined in the communication system of FIG. FIGS. 4A and 4B are diagrams illustrating the configuration of the priority area and the general area. FIGS. 5 (a)-(b) are diagrams showing the configuration of the subframes of FIGS. 3 (a)-(d). FIGS. 6A and 6B are diagrams showing a format of a MAC frame stored in a packet signal defined in the communication system of FIG. It is a figure which shows the structure of the terminal device mounted in the vehicle of FIG. It is a flowchart which shows the selection procedure of the priority period or the general period in the terminal device of FIG. It is a flowchart which shows the display procedure in the terminal device of FIG. It is a figure which shows the structure of the terminal device which concerns on the 1st modification of this invention. It is a flowchart which shows the process sequence in the terminal device of FIG. It is a flowchart which shows the process sequence in the terminal device which concerns on the 2nd modification of this invention. It is a figure which shows the structure of the communication system which concerns on the 3rd modification of this invention. It is a figure which shows the structure of the portable terminal device which concerns on the 4th modification of this invention. It is a figure which shows an example of the service menu which a vehicle-mounted terminal device provides to a portable terminal device. It is a flowchart which shows the process sequence of the portable terminal device which concerns on the 5th modification of this invention. It is a flowchart which shows the process sequence of the portable terminal device which concerns on the 6th modification of this invention. It is a flowchart which shows the process sequence in the reception process part which concerns on the 7th modification of this invention. It is a figure for demonstrating a 1st risk determination process and a 2nd risk determination process. It is a flowchart which shows the process sequence in the reception process part which concerns on the 8th modification of this invention. It is a flowchart which shows the process sequence in the transmission process part which concerns on the 9th modification of this invention.

The knowledge that became the basis of the examples of the present invention is as follows. 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 Avididance) is used. Therefore, in the wireless LAN, the same wireless channel is shared by a plurality of terminal devices. In such CSMA / CA, a packet signal is transmitted after confirming that no other packet signal is transmitted by carrier sense.

On the other hand, when a wireless LAN is applied to inter-vehicle communication such as ITS (Intelligent Transport Systems), it is necessary to transmit information to an unspecified number of terminal devices. . However, at an intersection or the like, an increase in the number of vehicles, that is, an increase in the number of terminal devices increases traffic, and therefore, an increase in packet signal collision is assumed. As a result, data included in the packet signal is not transmitted to other terminal devices. If such a situation occurs in vehicle-to-vehicle communication, the objective of preventing a collision accident at the intersection encounter will not be achieved. In addition, since various communication environments are assumed, it is desired to execute communication processing according to the communication environment.

An outline will be given before concretely explaining the present invention. Embodiments of the present invention relate to a communication system that performs vehicle-to-vehicle communication between terminal devices mounted on a vehicle, and also executes road-to-vehicle communication from a base station device installed at an intersection or the like to a terminal device. As inter-vehicle communication, the terminal device broadcasts and transmits a packet signal storing information such as the speed and position of the vehicle (hereinafter referred to as “data”). Further, the other terminal device receives the packet signal and recognizes the approach of the vehicle based on the data. Here, the base station apparatus repeatedly defines a frame including a plurality of subframes. The base station apparatus selects any of a plurality of subframes for road-to-vehicle communication, and broadcasts a packet signal in which control information and the like are stored during the period of the head portion of the selected subframe.

The control information includes information related to a period (hereinafter referred to as “road vehicle transmission period”) for the base station apparatus to broadcast the packet signal. The terminal device specifies a road and vehicle transmission period based on the control information, and transmits a packet signal in a period other than the road and vehicle transmission period. Thus, since the road-to-vehicle communication and the vehicle-to-vehicle communication are time-division multiplexed, the collision probability of packet signals between them is reduced. That is, when the terminal device recognizes the content of the control information, interference between road-vehicle communication and vehicle-to-vehicle communication is reduced. In addition, the area where the terminal device performing inter-vehicle communication is mainly classified into three types.

One is an area formed around the base station apparatus (hereinafter referred to as “first area”), and the other is an area formed outside the first area (hereinafter referred to as “second area”). Another one is an area formed outside the second area (hereinafter referred to as “outside the second area”). Here, in the first area and the second area, the terminal device can receive the packet signal from the base station apparatus with a certain quality, whereas outside the second area, the packet signal from the base station apparatus is received. The terminal device cannot receive with a certain quality. The first area is formed closer to the center of the intersection than the second area. Here, the following two situations are assumed depending on the shape of the intersection.

In the first situation, since the vehicle in the second area will enter the intersection from now on, the packet signal from the terminal device mounted on the vehicle can be said to be important information from the viewpoint of suppressing collision accidents. Is the case. The second situation is that the vehicle in the first area exists near the intersection, so the packet signal from the terminal device mounted on the vehicle is important information from the point of suppression of collision accidents. This is the case. Thus, it is required to set the priority according to the position where the packet signal should be transmitted. If the driver can recognize what priority is set in the area, it can be reflected in the driving. For example, if it is known that the vehicle is located in a high priority area, the possibility of a collision accident increases, so the driver can drive more carefully. For this reason, it is desired that the driver recognize what kind of priority exists in the set area.

Corresponding to such area regulations, a period for vehicle-to-vehicle communication (hereinafter referred to as “vehicle transmission period”) is formed by time division multiplexing of a priority period and a general period. The priority period is formed by a plurality of slots, and the terminal device broadcasts the packet signal by any of the plurality of slots. The general period has a predetermined period, and the terminal apparatus broadcasts a packet signal by the CSMA method during the general period. The terminal device existing outside the second area transmits a packet signal by the CSMA method regardless of the frame configuration. For the first situation described above, the terminal apparatus existing in the second area is made to use the priority period, and the terminal apparatus existing first is made to use the general period. In addition, for the second situation described above, the terminal apparatus existing in the first area uses the priority period, and the terminal apparatus existing in the second area uses the general period.

Here, it is determined in which area the terminal device mounted on the vehicle is present. It is preferable for the driver to be able to recognize which area is present. When the risk of a collision accident is higher in the priority area than in the general area, the driver can drive more carefully than before, if he / she recognizes that it is in the priority area. That is, the driver can be alerted. In order to cope with this, the terminal device notifies the driver of the area that currently exists, thereby allowing the driver to recognize that the area has changed.

FIG. 1 shows a configuration of a communication system 100 according to an embodiment of the present invention. This corresponds to a case where one intersection is viewed from above. The communication system 100 includes a base station device 10, a first vehicle 12a, a second vehicle 12b, a third vehicle 12c, a fourth vehicle 12d, a fifth vehicle 12e, a sixth vehicle 12f, and a seventh vehicle 12g, collectively referred to as a vehicle 12. , The eighth vehicle 12h, and the network 202. Each vehicle 12 is equipped with a terminal device (not shown). The first area 210 is formed around the base station apparatus 10, the second area 212 is formed outside the first area 210, and the second outside area 214 is formed outside the second area 212. ing.

As shown in the figure, 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 central portion. Here, the upper side of the drawing corresponds to the direction “north”, the left side corresponds to the direction “west”, the lower side corresponds to the direction “south”, and the right side corresponds to the direction “east”. The intersection of the two roads is an “intersection”. The first vehicle 12a and the second vehicle 12b are traveling from left to right, and the third vehicle 12c and the fourth vehicle 12d are traveling from right to left. Further, the fifth vehicle 12e and the sixth vehicle 12f are traveling from the top to the bottom, and the seventh vehicle 12g and the eighth vehicle 12h are traveling from the bottom to the top.

The communication system 100 arranges the base station apparatus 10 at the intersection. The base station device 10 controls communication between terminal devices. The base station device 10 repeatedly generates a frame including a plurality of subframes based on a signal received from a GPS satellite (not shown) and a frame formed by another base station device 10 (not shown). Here, the road vehicle transmission period can be set at the head of each subframe. The base station apparatus 10 selects a subframe in which the road and vehicle transmission period is not set by another base station apparatus 10 from among the plurality of subframes. The base station apparatus 10 sets a road and vehicle transmission period at the beginning of the selected subframe. The base station apparatus 10 notifies the packet signal in the set road and vehicle transmission period.

* Multiple types of data are assumed as data to be included in the packet signal. One is data such as traffic jam information and construction information, and the other is data relating to each slot included in the priority period. The latter includes slots that are not used in any terminal device (hereinafter referred to as “empty slots”), slots that are used in one terminal device (hereinafter referred to as “used slots”), and used in multiple terminal devices. Slot (hereinafter referred to as “collision slot”). A packet signal containing data such as traffic jam information and construction information (hereinafter referred to as “RSU packet signal”) and a packet signal including data relating to each slot (hereinafter referred to as “control packet signal”) are separately provided. Is generated. The RSU packet signal and the control packet signal are collectively referred to as “packet signal”.

A first area 210 and a second area 212 are formed around the communication system 100 according to the reception status when the terminal apparatus receives a packet signal from the base station apparatus 10. As shown in the figure, a first area 210 is formed in the vicinity of the base station apparatus 10 as an area having a relatively good reception status. It can be said that the first area 210 is formed near the central portion of the intersection. On the other hand, the second area 212 is formed outside the first area 210 as a region where the reception situation is worse than that of the first area 210. Further, outside the second area 212, an area outside the second area 214 is formed as an area where the reception status is worse than that in the second area 212. Note that the packet signal error rate and received power are used as the reception status.

The packet signal from the base station apparatus 10 includes two types of control information, one is information on the set road and vehicle transmission period (hereinafter referred to as “basic part”), and the other is Information on the set priority period (hereinafter referred to as “extended portion”). The terminal device generates a frame based on the basic part included in the received packet signal. As a result, the frame generated in each of the plurality of terminal devices is synchronized with the frame generated in the base station device 10. Further, the terminal device receives the packet signal broadcasted by the base station device 10, and based on the reception status of the received packet signal and the extended portion, the first area 210, the second area 212, and the second area outside It is estimated in which of 214.

Further, the extended portion included in the packet signal from the base station apparatus 10 includes information indicating the correspondence between the area and the vehicle transmission period (hereinafter referred to as “priority area identifier”). The information indicating the correspondence between the area and the vehicle transmission period can be said to be information indicating whether the priority period should be used in either the first area 210 or the second area 212. Here, the first arrangement and the second arrangement are defined. In the first arrangement, the general period is used in the first area 210 and the priority period is used in the second area 212. On the other hand, in the second arrangement, the priority period is used in the first area 210 and the general period is used in the second area 212. When the priority area identifier indicates the first arrangement and exists in the first area 210, the terminal device broadcasts the packet signal by carrier sense in the general period, and when the priority area identifier exists in the second area 212, priority is given. The packet signal is broadcast in any slot included in the period. When the priority area identifier indicates the second arrangement and exists in the first area 210, the terminal device broadcasts the packet signal in any slot included in the priority period and exists in the second area 212. When doing so, the packet signal is broadcast by carrier sense in the general period.

As a result, TDMA is executed in the priority period, and CSMA / CA is executed in the general period. Note that the terminal apparatus also selects subframes having the same relative timing in the next frame. In particular, in the priority period, the terminal device selects slots having the same relative timing in the next frame. Here, the terminal device acquires data and stores the data in a packet signal. The data includes, for example, information related to the location. The terminal device also stores control information in the packet signal. That is, the control information transmitted from the base station device 10 is transferred by the terminal device. On the other hand, when the terminal device is estimated to exist outside the second area 214, the terminal device broadcasts the packet signal by executing CSMA / CA regardless of the frame configuration.

FIG. 2 shows the configuration of the base station apparatus 10. The base station apparatus 10 includes an antenna 20, an RF unit 22, a modem unit 24, a processing unit 26, a control unit 30, and a network communication unit 80. The processing unit 26 includes a frame definition unit 40, a selection unit 42, a detection unit 44, a generation unit 46, and a setting unit 48. The RF unit 22 receives a packet signal from a terminal device (not shown) or another base station device 10 by the antenna 20 as a reception process. The RF unit 22 performs frequency conversion on the received radio frequency packet signal to generate a baseband packet signal. Further, the RF unit 22 outputs a baseband packet signal to the modem unit 24. In general, baseband packet signals are formed by in-phase and quadrature components, so two signal lines should be shown, but here only one signal line is shown for clarity. Shall be shown. The RF unit 22 also includes an LNA (Low Noise Amplifier), a mixer, an AGC, and an A / D conversion unit.

The RF unit 22 performs frequency conversion on the baseband packet signal input from the modem unit 24 as a transmission process, and generates a radio frequency packet signal. Further, the RF unit 22 transmits a radio frequency packet signal from the antenna 20 during the road-vehicle transmission period. The RF unit 22 also includes a PA (Power Amplifier), a mixer, and a D / A conversion unit.

The modem unit 24 demodulates the baseband packet signal from the RF unit 22 as a reception process. Further, the modem unit 24 outputs the demodulated result to the processing unit 26. The modem unit 24 also modulates the data from the processing unit 26 as a transmission process. Further, the modem unit 24 outputs the modulated result to the RF unit 22 as a baseband packet signal. Here, since the communication system 100 corresponds to the OFDM (Orthogonal Frequency Division Multiplexing) modulation method, the modem unit 24 also executes FFT (Fast Fourier Transform) as reception processing and IFFT (Inverse TransFastFast) as transmission processing. Also execute.

The frame defining unit 40 receives a signal from a GPS satellite (not shown), and acquires time information based on the received signal. In addition, since a well-known technique should just be used for acquisition of the information of time, description is abbreviate | omitted here. The frame defining unit 40 generates a plurality of frames based on the time information. For example, the frame defining unit 40 generates 10 frames of “100 msec” by dividing the period of “1 sec” into 10 on the basis of the timing indicated by the time information. By repeating such processing, the frame is defined to be repeated. Note that the frame defining unit 40 may detect the control information from the demodulation result and generate a frame based on the detected control information. Such processing corresponds to generating a frame synchronized with the timing of the frame formed by another base station apparatus 10. FIGS. 3A to 3D show frame formats defined in the communication system 100. FIG. FIG. 3A shows the structure of the frame. The frame is formed of N subframes indicated as the first subframe to the Nth subframe. For example, when the frame length is 100 msec and N is 8, a subframe having a length of 12.5 msec is defined. The description of FIGS. 3B to 3D will be described later, and returns to FIG.

The selection unit 42 selects a subframe in which a road and vehicle transmission period is to be set from among a plurality of subframes included in the frame. More specifically, the selection unit 42 receives a frame defined by the frame defining unit 40. The selection unit 42 inputs a demodulation result from another base station device 10 or a terminal device (not shown) via the RF unit 22 and the modem unit 24. The selection unit 42 extracts a demodulation result from another base station apparatus 10 from the input demodulation results. The extraction method will be described later. The selection unit 42 identifies the subframe that has not received the demodulation result by specifying the subframe that has received the demodulation result. This corresponds to specifying a subframe in which the road and vehicle transmission period is not set by another base station apparatus 10, that is, an unused subframe. When there are a plurality of unused subframes, the selection unit 42 selects one subframe at random. When there are no unused subframes, that is, when each of a plurality of subframes is used, the selection unit 42 acquires reception power corresponding to the demodulation result, and gives priority to subframes with low reception power. Select

FIG. 3B shows a configuration of a frame generated by the first base station apparatus 10a. The first base station apparatus 10a sets a road and vehicle transmission period at the beginning of the first subframe. Moreover, the 1st base station apparatus 10a sets a vehicle transmission period following the road and vehicle transmission period in a 1st sub-frame. The vehicle transmission period is a period during which the terminal device can notify the packet signal. That is, in the road and vehicle transmission period which is the head period of the first subframe, the first base station apparatus 10a can notify the packet signal, and in the frame, the terminal apparatus transmits in the vehicle and vehicle transmission period other than the road and vehicle transmission period. It is defined that the packet signal can be broadcast. Furthermore, the first base station apparatus 10a sets only the vehicle transmission period from the second subframe to the Nth subframe.

FIG. 3C shows a configuration of a frame generated by the second base station apparatus 10b. The second base station apparatus 10b sets a road and vehicle transmission period at the beginning of the second subframe. Also, the second base station apparatus 10b sets the vehicle transmission period from the first stage of the road and vehicle transmission period in the second subframe, from the first subframe and the third subframe to the Nth subframe. FIG. 3D shows a configuration of a frame generated by the third base station apparatus 10c. The third base station apparatus 10c sets a road and vehicle transmission period at the beginning of the third subframe. Also, the third base station apparatus 10c sets the vehicle transmission period from the first stage of the road and vehicle transmission period in the third subframe, the first subframe, the second subframe, and the fourth subframe to the Nth subframe. As described above, the plurality of base station apparatuses 10 select different subframes, and set the road and vehicle transmission period at the head portion of the selected subframe. Returning to FIG. The selection unit 42 outputs the selected subframe number to the detection unit 44 and the generation unit 46.

The setting unit 48 has an interface for receiving instructions from the business operator, and receives parameter setting instructions via the interface. For example, the interface is a button, and the setting unit 48 receives a parameter setting instruction by inputting to the button. The interface may be a connection terminal with a network communication unit 80 described later. At this time, the setting unit 48 receives a parameter setting instruction via the network communication unit 80, the network 202 (not shown), and the PC. Here, the parameter setting instruction is whether to use the first arrangement or the second arrangement. The setting unit 48 outputs the received setting instruction to the generation unit 46.

4 (a)-(b) are diagrams for explaining the configuration of the priority area and the general area. The first area 210, the second area 212, and the second outside area 214 shown in these figures are the same as those in FIG. FIG. 4A corresponds to the first arrangement. A first area 210 around the base station device 10 (not shown) is set as a general area. The general area is an area where the general period should be used. Therefore, the terminal device 14 existing in the general area can report the packet signal in the general period. A second area surrounding the first area 210 is set as a priority area. The priority area is an area where the priority period should be used. Therefore, the terminal device 14 existing in the priority area can broadcast the packet signal in each slot forming the priority period. FIG. 4B corresponds to the second arrangement. The first area 210 is set as the priority period, and the second area 212 is set as the general period. Note that the sizes of the first area 210 and the second area 212 may be different between the first arrangement and the second arrangement. Returning to FIG.

The detection unit 44 identifies whether each of the plurality of slots included in the priority period is unused, in use, or has a collision. Before describing the processing of the detection unit 44, the configuration of the subframe will be described here. FIGS. 5A to 5B show subframe configurations. As illustrated, one subframe is configured in the order of a road and vehicle transmission period, a priority period, and a general period. In the road and vehicle transmission period, the base station device 10 broadcasts the packet signal, the priority period is formed by time division multiplexing of a plurality of slots, and the terminal device 14 can broadcast the packet signal in each slot, The general period has a predetermined length, and the terminal device 14 can broadcast the packet signal. The priority period and the general period correspond to the vehicle transmission period shown in FIG. When the road and vehicle transmission period is not included in the subframe, the subframe is configured in the order of the priority period and the general period. At that time, the road and vehicle transmission period is also a priority period. FIG. 5B will be described later. Returning to FIG.

The detection unit 44 measures the received power for each slot and also measures the error rate for each slot. An example of the error rate is BER (Bit Error Rate). If the received power is lower than the received power threshold, the detection unit 44 determines that the slot is unused (hereinafter, such a slot is referred to as an “empty slot”). On the other hand, if the received power is equal to or greater than the received power threshold and the error rate is lower than the error rate threshold, the detection unit 44 is in use of the slot (hereinafter referred to as such a slot). It is determined as “used slot”. If the received power is equal to or greater than the threshold for received power and the error rate is equal to or greater than the threshold for error rate, the detection unit 44 has a collision in the slot (hereinafter referred to as such a slot). Are referred to as “collision slots”). The detection unit 44 executes such processing for all slots and outputs the results (hereinafter referred to as “detection results”) to the generation unit 46.

The generation unit 46 receives a setting instruction from the setting unit 48, receives a subframe number from the selection unit 42, and receives a detection result from the detection unit 44. The generation unit 46 sets a road and vehicle transmission period in the subframe of the received subframe number, and generates a control packet signal and an RSU packet signal to be notified during the road and vehicle transmission period. FIG. 5B shows the arrangement of packet signals during the road and vehicle transmission period. As illustrated, one control packet signal and a plurality of RSU packet signals are arranged in the road and vehicle transmission period. Here, the front and rear packet signals are separated by SIFS (Short Interframe Space). Returning to FIG.

Here, the configuration of the control packet signal and the RSU packet signal will be described. FIGS. 6A and 6B show the format of the MAC frame stored in the packet signal defined in the communication system 100. FIG. FIG. 6A shows the format of the MAC frame. In the MAC frame, “MAC header”, “LLC header”, “message header”, “data payload”, and “FCS” are arranged in order from the top. When the detection result is included in the data payload, the packet signal storing the MAC frame corresponds to the control packet signal. Further, when receiving data such as traffic jam information and construction information from the network communication unit 80, the generation unit 46 includes them in the data payload. A packet signal storing such a MAC frame corresponds to an RSU packet signal. Here, the network communication unit 80 is connected to a network 202 (not shown). The packet signal broadcasted in the priority period and the general period also stores the MAC frame shown in FIG.

FIG. 6B is a diagram illustrating a configuration of a message header generated by the generation unit 46. The message header includes a basic part and an extended part. As described above, since the control packet signal and the RSU packet signal have the same configuration, they include a basic part and an extended part. The basic part includes “protocol version”, “transmission node type”, “reuse count”, “TSF timer”, “RSU transmission period length”, and the extended part includes “vehicle slot size”, “priority general ratio” "," Priority general threshold value "," priority area identifier ".

Protocol version indicates the version of the supported protocol. The transmission node type indicates the transmission source of the packet signal including the MAC frame. For example, “0” indicates a terminal device, and “1” indicates the base station device 10. When the selection unit 42 extracts a demodulation result from another base station apparatus 10 from among the input demodulation results, the selection unit 42 uses the value of the transmission node type. The reuse count indicates an index of validity when the message header is transferred by the terminal device, and the TSF timer indicates the transmission time. The RSU transmission period length indicates the length of the road and vehicle transmission period, and can be said to be information relating to the road and vehicle transmission period.

The car slot size indicates the size of the slot included in the priority period, the priority general ratio indicates the ratio between the priority period and the general period, and the priority general threshold indicates whether the priority period is used or the general period is used. It is a threshold value for causing the terminal device 14 to select and a threshold value for the received power. The priority area identifier is an identifier for indicating which one of the first arrangement and the second arrangement is used. Here, when the first arrangement is used, that is, when the arrangement of FIG. 4A is used, the priority area identifier is set to “0”. When the second arrangement is used, that is, when the arrangement shown in FIG. 4B is used, the priority area identifier is set to “1”. Thus, the extended portion corresponds to information on the priority period and the general period. Returning to FIG.

The processing unit 26 broadcasts the packet signal to the modem unit 24 and the RF unit 22 during the road and vehicle transmission period. That is, the processing unit 26 broadcasts the control packet signal and the RSU packet signal including the basic part and the extended part in the base station broadcast period. The control unit 30 controls processing of the entire base station apparatus 10.

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 only by hardware, or by a combination of hardware and software.

FIG. 7 shows the configuration of the terminal device 14 mounted on the vehicle 12. The terminal device 14 includes an antenna 50, an RF unit 52, a modem unit 54, a processing unit 56, and a control unit 58. The processing unit 56 includes a generation unit 64, a timing identification unit 60, a transfer determination unit 90, a notification unit 70, and an acquisition unit 72. The timing specifying unit 60 includes an extraction unit 66, a selection unit 92, and a carrier sense unit 94. The antenna 50, the RF unit 52, and the modem unit 54 execute the same processing as the antenna 20, the RF unit 22, and the modem unit 24 in FIG. Therefore, here, the difference will be mainly described.

The modem unit 54 and the processing unit 56 receive packet signals from other terminal devices 14 and the base station device 10 (not shown). As described above, the modem unit 54 and the processing unit 56 receive the packet signal from the base station apparatus 10 during the road and vehicle transmission period. As described above, the modem unit 54 and the processing unit 56 receive packet signals from other terminal apparatuses 14 in the priority period and the general period.

When the demodulation result from the modem unit 54 is a packet signal from the base station device 10 (not shown), the extraction unit 66 specifies the timing of the subframe in which the road-vehicle transmission period is arranged. Further, the extraction unit 66 generates a frame based on the subframe timing and the content of the basic part in the message header of the packet signal, specifically, the content of the RSU transmission period length. Note that the generation of the frame only needs to be performed in the same manner as the frame defining unit 40 described above, and thus the description thereof is omitted here. As a result, the extraction unit 66 generates a frame synchronized with the frame formed in the base station apparatus 10.

The extraction unit 66 measures the received power of the packet signal from the base station apparatus 10. Based on the measured received power, the extraction unit 66 estimates whether it exists in the first area 210, the second area 212, or outside the second area 214. For example, the extraction unit 66 stores an area determination threshold value. The area determination threshold corresponds to the above-described priority general threshold. If the received power is larger than the area determination threshold, the extraction unit 66 determines that the first area 210 exists. If the received power is equal to or less than the area determination threshold, the extraction unit 66 determines that the second area 212 exists. When the packet signal from the base station apparatus 10 has not been received, the extraction unit 66 determines that it exists outside the second area 212. Note that the extraction unit 66 may use an error rate instead of the received power, or may use a combination of the received power and the error rate.

The extraction unit 66 determines whether the currently existing area is a priority area or a general area based on the estimation result and the priority area identifier. When the priority area identifier is “1”, the extraction unit 66 selects the priority area if it exists in the first area 210, and selects the general area if it exists in the second area 212. On the other hand, when the priority area identifier is “0”, the extraction unit 66 selects the general area if it exists in the first area 210 and selects the priority area if it exists in the second area 212.

Further, when estimating that the extraction unit 66 exists outside the second area 214, the extraction unit 66 selects a timing unrelated to the frame configuration. The extraction unit 66 selects a general period when a general area is selected. When selecting the priority area, the extraction unit 66 selects a priority period. When selecting the priority period, the extraction unit 66 outputs the detection result included in the data payload of the control packet signal to the selection unit 92. When the general period is selected, the extraction unit 66 outputs information on the frame and subframe timing and the vehicle transmission period to the carrier sense unit 94. When selecting the timing irrelevant to the frame configuration, the extraction unit 66 instructs the carrier sense unit 94 to execute carrier sense.

The selection unit 92 receives the detection result from the extraction unit 66. As described above, the detection result indicates whether each of the plurality of slots included in the priority period is an empty slot, a used slot, or a collision slot. The selection unit 92 selects one of the empty slots. If a slot has already been selected, the selection unit 92 continues to select the same slot if the slot is a used slot. On the other hand, when the slot has already been selected, the selection unit 92 newly selects an empty slot if the slot is a collision slot. The selection unit 92 notifies the generation unit 64 of information related to the selected slot as a transmission timing.

The carrier sense unit 94 receives information on frame and subframe timing and vehicle transmission period from the extraction unit 66. The carrier sense unit 94 measures the interference power by performing carrier sense in the general period. Further, the carrier sense unit 94 determines the transmission timing in the general period based on the interference power. More specifically, the carrier sense unit 94 stores a predetermined threshold value in advance, and compares the interference power with the threshold value. If the interference power is smaller than the threshold value, the carrier sense unit 94 determines the transmission timing. When receiving the carrier sense execution instruction from the extraction unit 66, the carrier sense unit 94 determines the transmission timing by executing the CSMA without considering the frame configuration. The carrier sense unit 94 notifies the generation unit 64 of the determined transmission timing.

The acquisition unit 72 includes a GPS receiver (not shown), a gyroscope, a vehicle speed sensor, and the like. Based on data supplied from these, the location of the vehicle 12 (not shown), that is, the position of the vehicle 12 on which the terminal device 14 is mounted, the progress The direction, the moving speed, etc. (hereinafter collectively referred to as “position information”) are acquired. The existence position is indicated by latitude and longitude. Since a known technique may be used for these acquisitions, description thereof is omitted here. The acquisition unit 72 outputs the position information to the generation unit 64.

The transfer determination unit 90 controls the transfer of the message header. The transfer determining unit 90 extracts a message header from the packet signal. When the packet signal is directly transmitted from the base station apparatus 10, the reuse count is set to “0”. However, when the packet signal is transmitted from another terminal apparatus 14, the reuse is performed. The number of times is set to a value of “1 or more”. The transfer determining unit 90 selects a message header to be transferred from the extracted message header. Here, for example, the message header with the smallest number of reuses is selected. Further, the transfer determination unit 90 may generate a new message header by combining the contents included in the plurality of message headers. The transfer determination unit 90 outputs the message header to be selected to the generation unit 64. At that time, the transfer determining unit 90 increases the number of reuses by “1”.

The generation unit 64 receives position information from the acquisition unit 72 and receives a message header from the transfer determination unit 90. The generation unit 64 uses the MAC frame shown in FIGS. 6A to 6B and stores the position information in the data payload. The generation unit 64 generates a packet signal including a MAC frame, and generates the packet signal via the modulation / demodulation unit 54, the RF unit 52, and the antenna 50 at the transmission timing determined by the selection unit 92 or the carrier sense unit 94. Broadcast packet signals. The transmission timing is included in the vehicle transmission period.

The notification unit 70 acquires a packet signal from the base station apparatus 10 (not shown) in the road and vehicle transmission period, and acquires a packet signal from another terminal apparatus 14 (not shown) in the vehicle and vehicle transmission period. As a process for the acquired packet signal, the notification unit 70 notifies the driver of the approach of another vehicle 12 (not shown) or the like via a monitor or a speaker in accordance with the content of data stored in the packet signal.

As described above, the extraction unit 66 identifies either the first area 210, the second area 212, or the second area 214. Here, the first area 210, the second area 212, and the second outside area 214 can be said to be areas having different priorities. In the case of the second arrangement, since the first area 210 corresponds to the priority area and the second area 212 corresponds to the general area, the priority of the first area 210 is the highest, and the priority of the second area 212 is the next. High and the priority outside 214 in the second area is low. In this case, it can be said that the priority of each area is defined according to the importance of the signal to be notified. On the other hand, in the first arrangement, since the first area 210 corresponds to the general area and the second area 212 corresponds to the priority area, the second area 212 has the highest priority, and the first area 210 has the highest priority. Next, the priority of 214 outside the second area is low.

Moreover, it can be said that the priority for the first area 210 and the second area 212 is determined according to the quality of the received signal. In the second arrangement, the first area 210 with higher reception quality has a higher priority than the second area 212 with lower reception quality. In the first arrangement, the second area 212 having a lower reception quality has a higher priority than the first area 210 having a higher reception quality. Furthermore, it can be said that the priority for the first area 210 and the second area 212 is determined according to the distance to the base station apparatus 10. In the case of the second arrangement, the first area 210 with a shorter distance has a higher priority than the second area 212 with a longer distance. In the case of the first arrangement, the second area 212 having a longer distance has a higher priority than the first area 210 having a shorter distance.

The extraction unit 66 detects movement to a different area by monitoring an existing area. For example, movement from a priority area to a general area. The reverse movement may be used. Furthermore, the movement may be between the second area 212 and the second area 214, such as between the general area and the second area 214, or between the priority area and the second area 214. . When detecting the movement, the extraction unit 66 changes the instruction to the selection unit 92 and the carrier sense unit 94. For example, when the movement from the priority area to the general area is detected, the extraction unit 66 changes the communication process defined in the priority area to the communication process defined in the general area. Specifically, the instruction to the selection unit 92 is changed to an instruction to the carrier sense unit 94.

When the extraction unit 66 detects a movement between the second area 212 and the second area 214, the extraction unit 66 performs a communication process between the communication process in the second area 212 and the communication process in the second area 214. change. The communication processing in the second area 212 is the use of the priority period by the selection unit 92 or the general period by the carrier sense unit 94. Since these are operations constrained by the frame configuration, it can be said that the operations correspond to the operation timing of the base station apparatus 10. On the other hand, the communication processing outside the second area 214 is an operation that does not depend on the frame configuration by the carrier sense unit 94. This can be said to be an operation unrelated to the operation timing of the base station apparatus 10. The extraction unit 66 notifies the notification unit 70 of the area change by notifying the notification unit 70 of the existing area.

The notification unit 70 notifies the driver of the existing area based on the area information received from the extraction unit 66. For example, when the notification unit 70 exists in the priority area, the vehicle in the navigation system is displayed in red. The notification part 70 displays the own vehicle in a navigation system in yellow, when it exists in a general area. When the notification unit 70 exists outside the second area 214, the notification unit 70 displays the host vehicle in the navigation system in blue. In this way, the display color of the host vehicle is changed according to the existing area, which corresponds to changing the notification mode according to the existing area. As a result, the notification unit 70 notifies the area change when the movement is detected. The notification unit 70 may output a warning sound when entering the priority area, or may output a warning by voice. That is, it is only necessary for the driver to be informed that the vehicle has entered the priority area. A similar process may be performed in the movement between the second area 212 and the second area outside 214. The control unit 58 controls the operation of the entire terminal device 14.

The operation of the communication system 100 configured as above will be described. FIG. 8 is a flowchart showing a procedure for selecting a priority period or a general period in the terminal device 14. If the priority area identifier is “1” (Y in S30) and the received power is larger than the threshold (Y in S32), the extraction unit 66 determines the use of the priority period (S34). If the received power is not greater than the threshold value (N in S32), the extraction unit 66 determines the use of the general period (S36). If the priority area identifier is not “1” (N in S30) and the received power is larger than the threshold value (Y in S38), the extraction unit 66 determines the use of the general period (S40). If the received power is not greater than the threshold (N in S38), the extraction unit 66 determines the use of the priority period (S42).

FIG. 9 is a flowchart showing a display procedure in the terminal device 14. When it exists in a priority area (Y of S60), the notification part 70 displays the vehicle 12 in red (S62). On the other hand, when it does not exist in the priority area (N in S60) and exists in the general area (Y in S64), the notification unit 70 displays the vehicle 12 in yellow (S66). When it does not exist in the general area (N in S64), the notification unit 70 displays the vehicle 12 in blue (S68).

Next, a first modification of the present invention will be described. The first modification of the present invention also relates to a terminal device that broadcasts a packet signal in which position information and the like are stored. In the embodiment, the terminal device is mounted on a vehicle. On the other hand, in the first modification, the terminal device is carried by the user and moved. Since such a terminal device is operated by a built-in battery, low power consumption is desired. On the other hand, in order to ensure the safety of the user, the terminal device is required to inform the vehicle of the location of the user by transmitting a packet signal. Furthermore, when the user gets on the vehicle while carrying the terminal device, the terminal device is also desired to operate similarly to the terminal device mounted on the vehicle.

To cope with this, the terminal device according to the first modification, when present outside the vehicle, executes only the transmission process of the packet signal and stops the reception process of the packet signal. On the other hand, when the terminal device is present in the vehicle, the terminal device performs a packet signal transmission process and a reception process. Here, the terminal device is estimated to exist outside the vehicle when operating with the built-in battery, and is estimated to exist within the vehicle when operating with the external power source. The communication system 100 according to the first modification is the same type as that in FIG. 1, and the base station apparatus 10 is the same type as that in FIG. Below, it demonstrates focusing on a difference.

FIG. 10 shows a configuration of the terminal device 14 according to the first modification of the present invention. The terminal device 14 includes an antenna 50, an RF unit 52, a modem unit 54, a processing unit 56, a control unit 58, and a connection unit 88. The processing unit 56 includes a transmission processing unit 82, a reception processing unit 84, and an estimation unit 86. Since the antenna 50, the RF unit 52, and the modem unit 54 perform the same operations as those in FIG. 7, the description thereof is omitted here. The transmission processing unit 82 corresponds to a part of the processing unit 56 in FIG. 7 that executes a process for informing a packet signal, and the reception processing unit 84 includes the packet signal in the processing unit 56 in FIG. This corresponds to the part that executes the process for receiving. Here, the terminal device 14 is configured to be portable by the user, for example, like a mobile phone terminal.

The connection unit 88 is connected to a power supply terminal provided in the vehicle 12 (not shown). The connection unit 88 receives power supply from the power supply terminal and drives the terminal device 14. On the other hand, when the terminal device 14 exists outside the vehicle 12, the connection unit 88 is not connected to the power supply terminal and does not accept supply of power. At that time, the terminal device 14 is driven by an internal battery (not shown).

<The estimation part 86 detects whether the connection part 88 is connected to the power supply terminal. Since a known technique may be used for the detection, description thereof is omitted here. When the estimation unit 86 detects that it is connected to the power supply terminal, the estimation unit 86 estimates that it exists in the vehicle 12. When the estimation unit 86 detects that it is not connected to the power supply terminal, the estimation unit 86 estimates that it exists outside the vehicle 12. That is, the estimation unit 86 estimates whether the terminal device 14 exists in the vehicle 12 or outside the vehicle 12. When estimating that the vehicle is present in the vehicle 12, the estimation unit 86 operates the transmission processing unit 82 and the reception processing unit 84 to perform transmission processing and reception processing. On the other hand, when the estimation unit 86 estimates that the vehicle exists outside the vehicle 12, the estimation unit 86 stops one of the transmission processing and the reception processing by stopping one of the transmission processing unit 82 and the reception processing unit 84. For example, the estimation unit 86 operates only the transmission processing unit 82 and stops the reception processing unit 84. Note that the reverse may be possible.

FIG. 11 is a flowchart showing a processing procedure in the terminal device 14. If it is battery driven (Y of S80), the estimation part 86 will perform a transmission process and will stop a reception process (S82). On the other hand, if the battery is not driven (N in S80), the estimation unit 86 causes the transmission process and the reception process to be executed (S84).

Next, a second modification of the present invention will be described. The 2nd modification of this invention is related with the terminal device comprised so that a user might move like the 1st modification. The second modification of the present invention is directed to the case where the terminal device is outside the vehicle. In the first modification, when the terminal device exists outside the vehicle, one of the transmission process and the reception process is stopped for the purpose of reducing power consumption. On the other hand, even when the terminal device exists outside the vehicle, it may be desired to operate the transmission process and the reception process. In order to cope with this, the terminal device according to the second modification of the present invention executes transmission processing and reception processing when approaching the base station device. The communication system 100 according to the second modification is the same type as in FIG. 1, the base station apparatus 10 is the same type as in FIG. 2, and the terminal apparatus 14 is the same type as in FIG. 7 and FIG. It is. Below, it demonstrates focusing on a difference.

When the extraction unit 66 does not receive the packet signal from the base station apparatus 10, that is, when it exists outside the second area 214 in FIG. 1, the estimation unit 86 is one of the transmission processing unit 82 and the reception processing unit 84. Is stopped, one of the transmission process and the reception process is stopped. On the other hand, when the extraction unit 66 receives the packet signal from the base station apparatus 10, that is, when the extraction unit 66 exists in the first area 210 and the second area 212 in FIG. The transmission process and the reception process are executed by operating the unit 84.

In addition, the connection unit 88 may switch the operation depending on whether or not it exists in the first area 210 instead of switching the operation depending on whether or not the packet signal from the base station apparatus 10 is received. For example, when it exists in the 1st area 210, the estimation part 86 operates the transmission process part 82 and the reception process part 84. FIG. On the other hand, when it exists in the 2nd area 212 and the 2nd outside area 214, the estimation part 86 stops one of the transmission process part 82 and the reception process part 84. FIG.

FIG. 12 is a flowchart showing a processing procedure in the terminal device 14 according to the second modification of the present invention. If the packet signal from the base station apparatus 10 is not received (N in S90), the estimation unit 86 executes the transmission process and stops the reception process (S92). On the other hand, if the packet signal from the base station apparatus 10 is received (Y in S90), the estimation unit 86 causes transmission processing and reception processing to be executed (S94).

Next, a third modification will be described. Until now, a priority area and a general area, that is, two types of areas, have been defined, and a priority period and a general period are used in each area. On the other hand, in the third modified example, one of the priority area and the general area, that is, one type of area is defined, and one of the priority period and the general period is used to correspond thereto. Yes. FIG. 13 shows a configuration of a communication system 100 according to the third modification of the present invention. This corresponds to the case where one intersection is viewed from above, as in FIG. Compared with FIG. 1, FIG. 13 does not form the first area 210 but forms only the second area 212. In order to correspond to this, in the subframe configuration shown in FIG. 5A, only one of the priority period and the general period is included. Here, it is assumed that only the general period is included. Therefore, the vehicle transmission period in FIGS. 3B to 3D corresponds to the general period.

The base station apparatus 10 according to the third modification is the same type as that in FIG. 2, but does not execute processing related to the priority period. For this reason, the priority period is not included in the configuration of subframes and frames defined by the frame defining unit 40. The setting unit 48 may be omitted. The terminal device 14 according to the third modification is of the same type as that shown in FIGS. Similarly to the base station apparatus 10, the terminal apparatus 14 does not execute processing related to the priority period. In particular, the extraction unit 66 identifies whether it exists in the second area 212 or outside the second area 214. This specification is made based on whether or not a packet signal from the base station apparatus 10 is received. Specifically, when receiving a packet signal from the base station apparatus 10, the extraction unit 66 identifies the presence in the second area 212 and has not received the packet signal from the base station apparatus 10. In this case, the extraction unit 66 identifies the presence outside the second area 214. Further, the extraction unit 66 detects a movement from the second area outside 214 to the second area 212 and a movement from the second area outside 214 to the second area 212.

When the extraction unit 66 detects a movement between the second area 212 and the second area 214, the extraction unit 66 performs a communication process between the communication process in the second area 212 and the communication process in the second area 214. change. The communication processing in the second area 212 is use of a general period by the carrier sense unit 94. Since this is an operation constrained by the frame configuration, it can be said to be an operation according to the operation timing of the base station apparatus 10. On the other hand, the communication processing outside the second area 214 is an operation that does not depend on the frame configuration by the carrier sense unit 94. This can be said to be an operation unrelated to the operation timing of the base station apparatus 10.

Next, a fourth modification will be described. The terminal device according to the fourth modification is also carried by the user and moved. Since the terminal device operates with a built-in battery, low power consumption is desired. On the other hand, in order to ensure the safety of the user, it is required to inform the vehicle of the location of the user by transmitting a packet signal. Hereinafter, a terminal device carried by a user is referred to as a portable terminal device, and a terminal device installed at a predetermined position in the vehicle is referred to as an in-vehicle terminal device.

To cope with this, the portable terminal device according to the fourth modified example transmits a packet signal with lower transmission power when present in the vehicle than when present in the vehicle. Here, the portable terminal device estimates whether it exists in the vehicle or outside the vehicle from the received strength (RSSI: Received Signal Strength Indication) of the packet signal broadcast from the in-vehicle terminal device. The communication system 100 according to the fourth modification is the same type as that in FIG. 1, and the base station apparatus 10 is the same type as that in FIG. Below, it demonstrates focusing on a difference.

FIG. 14 shows a configuration of a portable terminal device 14a according to a fourth modification of the present invention. The portable terminal device 14a includes an antenna 50, an RF unit 52, a modem unit 54, a processing unit 56, and a control unit 58. The processing unit 56 includes a transmission processing unit 82, a reception processing unit 84, a transmission power adjustment unit 85, and an estimation unit 86. Since the antenna 50, the RF unit 52, and the modem unit 54 perform the same operations as those in FIG. 7, the description thereof is omitted here. The transmission processing unit 82 corresponds to a part of the processing unit 56 in FIG. 7 that executes a process for informing a packet signal, and the reception processing unit 84 includes the packet signal in the processing unit 56 in FIG. This corresponds to the part that executes the process for receiving. The generation unit 64, the notification unit 70, and the acquisition unit 72 of FIG. 7 are omitted in FIG. 14 to simplify the drawing, but are included in the processing unit 56. The portable terminal device 14a is driven by a built-in battery.

The estimation unit 86 detects the RSSI of the packet signal notified from the in-vehicle terminal device, and estimates whether the portable terminal device 14a exists inside the vehicle 12 or outside the vehicle 12. Since the distance between the transmitting terminal and the receiving terminal can be estimated by RSSI, it can be estimated whether or not the vehicle 12 exists. Since the in-vehicle terminal device exists in the vehicle 12, if a general passenger car is assumed, if it can be estimated that the portable terminal device 14a exists within about 1.5 m from the in-vehicle terminal device, it may exist in the vehicle 12. Judgment is high.

The designer sets a setting value corresponding to the distance from the in-vehicle terminal device, which is estimated that the portable terminal device 14a exists in the vehicle 12, in the estimation unit 86. The estimation unit 86 estimates whether the portable terminal device 14a exists inside the vehicle 12 or outside the vehicle 12 by comparing the set value with the RSSI of the packet signal notified from the in-vehicle terminal device. . When packet signals are received from a plurality of in-vehicle terminal devices during a certain period, the estimation unit 86 compares the highest RSSI with the set value.

Note that whether or not the transmission source of the packet signal is an in-vehicle terminal device can be specified by referring to the transmission source type stored in the header of the MAC frame. When the transmission source type is a base station device and a portable terminal device, the packet signal is not used for determining whether or not the portable terminal device 14a exists in the vehicle 12.

The estimation unit 86 sets in the transmission processing unit 82, the reception processing unit 84, and the transmission power adjustment unit 85 whether the portable terminal device 14a is estimated to be present in the vehicle 12 or is estimated to exist outside the vehicle 12. To do.

The transmission processing unit 82 receives position information from a GPS receiver or the like, and stores the position information in the data payload of the MAC frame. The transmission processing unit 82 broadcasts and transmits a packet signal including the MAC frame at a predetermined timing. The transmission power adjustment unit 85 adjusts transmission power when a packet signal is transmitted by the transmission processing unit 82, the modem unit 54, the RF unit 52, and the antenna 50. Specifically, the transmission power adjustment unit 85 sets the transmission power when it is estimated that the portable terminal device 14a exists in the vehicle 12 to be lower than the transmission power when it is estimated that the portable terminal device 14a exists outside the vehicle 12. .

When it is estimated that the portable terminal device 14a is present in the vehicle 12, it can be said that the user carrying the portable terminal device 14a is in a safe position, and therefore the necessity of notifying other vehicles of the presence is not necessary. Low. On the other hand, when it is estimated that the portable terminal device 14a exists outside the vehicle 12, it is highly necessary to notify the vehicle located in the vicinity of the presence of a pedestrian carrying the portable terminal device 14a.

When it is estimated that the portable terminal device 14a exists in the vehicle 12, the transmission power adjustment unit 85 adjusts the transmission power so that the packet signal is transmitted with a radio wave intensity reaching within a radius of 1 to 2 m, for example. When it is estimated that the portable terminal device 14a is present in the vehicle 12, the portable terminal device 14a only needs to be able to communicate with the in-vehicle terminal device in the vehicle 12, so that the in-vehicle terminal device installed in the vehicle 12 receives the signal. It is good to adjust to the lowest possible transmission power.

On the other hand, when it is estimated that the portable terminal device 14a exists outside the vehicle 12, the transmission power adjustment unit 85 adjusts the transmission power so that a packet signal is transmitted with a radio wave intensity reaching within a radius of 5 to 100 m, for example. From the viewpoint of traffic safety, it is desirable to transmit by radio waves that reach a long distance, but from the viewpoint of traffic of the battery of the portable terminal device 14a and the communication system 100 as a whole, radio waves that can reach only a short distance are used. It is desirable to send it out. The designer considers this trade-off relationship, and sets the transmission power when the portable terminal device 14a is estimated to exist outside the vehicle 12.

The reception processing unit 84 receives various types of information from the in-vehicle terminal device when it is estimated that the portable terminal device 14a exists in the vehicle 12. The in-vehicle terminal device is generally installed in the vicinity of the driver's seat in the vehicle 12. When a user carrying the portable terminal device 14a is on the rear seat of the vehicle 12, it is difficult to see or operate the screen of the in-vehicle terminal device. Therefore, the in-vehicle terminal device and the portable terminal device 14a communicate with each other, so that the user sitting in the rear seat can use the service provided by the in-vehicle terminal device in the portable terminal device 14a.

The generation unit 53 of the in-vehicle terminal device generates a packet signal including a service menu provided to the portable terminal device 14a, and the transmission processing unit 82 notifies the packet signal. The reception processing unit 84 of the portable terminal device 14a receives the packet signal.

FIG. 15 is a diagram illustrating an example of a service menu provided by the in-vehicle terminal device to the portable terminal device 14a. In this example, road alignment information, traffic jam information, construction information, accident information, and weather information are provided. FIG. 15 shows a service menu screen 70a displayed on the display of the portable terminal device 14a. A user carrying the portable terminal device 14a selects a menu. For example, the corresponding area of the touch panel display is touched. Or use the operation keys to select the menu. The generation unit 64 of the portable terminal device 14a generates a packet signal including the selection information, and the transmission processing unit 82 notifies the packet signal.

The reception processing unit 84 of the in-vehicle terminal device receives the packet signal. The generating unit 64 of the in-vehicle terminal apparatus generates a packet signal including menu service information corresponding to the selection information. The transmission processing unit 82 notifies the packet signal. The generation unit 64 can use various service information such as road alignment information, traffic jam information, construction information, accident information, and weather information acquired from the base station device 10, other in-vehicle terminal devices, or navigation devices.

The reception processing unit 84 of the portable terminal device 14a receives the packet signal, and the notification unit 70 displays the service information included in the packet signal on the screen. The above-described exchange of information between the in-vehicle terminal device and the portable terminal device 14a is executed by the above-described inter-vehicle communication.

When the estimation unit 86 estimates that the vehicle exists outside the vehicle 12, the reception processing unit 84 stops the reception process by stopping the reception processing unit 84. In the fourth modification, the stop of the reception process means that the data stored in the data payload of the packet signal is discarded without being processed. The reception processing unit 84 may stop the reception process of the packet signal regardless of the transmission source type, or may stop the reception process of the packet signal notified from another terminal device 14. In the former, reception processing of all packet signals notified from the in-vehicle terminal device, the other portable terminal device 14a, and the base station device 10 is stopped. In the latter case, the reception processing of the packet signal notified from the in-vehicle terminal device and the other portable terminal device 14a is stopped, but the reception processing of the packet signal notified from the base station device 10 is not stopped.

In the latter case, when the portable terminal device 14a is located within the radio wave range of the base station device 10, the base station device 10 provides the portable terminal device 14a by communicating with the base station device 10. The service can be used by the portable terminal device 14a. The generation unit 46 of the base station apparatus 10 generates a packet signal including a service menu provided to the portable terminal apparatus 14a, and a transmission processing unit (not shown) of the base station apparatus 10 notifies the packet signal. The service menu includes traffic information, construction information, accident information, incident information, weather information, and the like.

The reception processing unit 84 of the portable terminal device 14a receives the packet signal notified from the base station device 10, and the notification unit 70 displays a service menu included in the packet signal on the screen. A user carrying the portable terminal device 14a selects a menu. The generation unit 64 of the portable terminal device 14a generates a packet signal including the selection information, and the transmission processing unit 82 notifies the packet signal.

A reception processing unit (not shown) of the base station apparatus 10 receives the packet signal. The generation unit 46 of the base station apparatus 10 generates a packet signal including service information of a menu corresponding to the selection information. A transmission processing unit (not shown) of the base station apparatus 10 broadcasts the packet signal. The generation unit 46 can use various service information such as traffic information, construction information, accident information, incident information, and weather information acquired from various servers on the network 202, other base station devices 10, and terminal devices 14.

The reception processing unit 84 of the portable terminal device 14a receives the packet signal, and the notification unit 70 displays the service information included in the packet signal on the screen. The above-described information exchange between the base station device 10 and the portable terminal device 14a is executed by the road-to-vehicle communication described above.

FIG. 16 is a flowchart showing a processing procedure of the portable terminal device 14a according to the fourth modification. When the packet signal is received from the in-vehicle terminal device, the estimation unit 86 detects the reception intensity of the packet signal (S90). The estimation unit 86 compares the received intensity with the set value (S92). When the reception intensity is less than the set value (Y in S92), the estimation unit 86 estimates that the portable terminal device 14a exists outside the vehicle 12, and the transmission power adjustment unit 85 sets the transmission power to normal transmission power. The unit 82 transmits the packet signal with normal transmission power (S94). The reception processing unit 84 stops receiving packet signals broadcast from other terminal devices (S96).

If the reception intensity is greater than or equal to the set value in step S92 (N in S92), the estimation unit 86 estimates that the portable terminal device 14a is present in the vehicle 12, and the transmission power adjustment unit 85 sets the transmission power to lower than normal. Then, the transmission processing unit 82 transmits the packet signal with low transmission power (S98).

Next, a fifth modification will be further described. The terminal device according to the fifth modification is also carried by the user and moved. In the fifth modification, the built-in battery of the portable terminal device 14a is further saved. When the portable terminal device according to the fifth modification is present in the vehicle, the portable terminal device transmits a packet signal including the position information at a lower frequency than when the portable terminal device is present outside the vehicle. The communication system 100 according to the fifth modification is the same type as that in FIG. 1, and the base station apparatus 10 is the same type as that in FIG. The in-vehicle terminal device is the same type as in FIG. 7, and the portable terminal device 14a is the same type as in FIG. Below, it demonstrates focusing on a difference.

When the estimation unit 86 estimates that the portable terminal device 14a is present in the vehicle 12, the transmission processing unit 82 of the portable terminal device 14a performs position information less frequently than when it is estimated that the portable terminal device 14a exists outside the vehicle 12. A packet signal including When the user carrying the portable terminal device 14a is in the vehicle 12, the necessity of notifying other vehicles of the presence is low. When the portable terminal device 14a exists in the vehicle 12, the packet signal including the position information is notified because the in-vehicle terminal device checks whether the portable terminal device 14a exists in the vehicle 12. Is the main purpose. As a result of the confirmation, the in-vehicle terminal device notifies the packet signal including the service menu described above when the portable terminal device 14a is present in the vehicle 12, and does not notify the packet signal when it does not exist. For example, when the estimation unit 86 estimates that the portable terminal device 14a exists outside the vehicle 12, the transmission processing unit 82 transmits a packet signal including position information once every 100 msec and estimates that the portable terminal device 14a exists inside the vehicle 12. If transmitted, it is transmitted once every 1 min.

FIG. 17 is a flowchart showing a processing procedure of the portable terminal device 14a according to the fifth modification. The flowchart of FIG. 17 has a configuration in which steps S95 and S98 are added to the flowchart of FIG. When the packet signal is received from the in-vehicle terminal device, the estimation unit 86 detects the reception intensity of the packet signal (S90). The estimation unit 86 compares the received intensity with the set value (S92). When the reception intensity is less than the set value (Y in S92), the estimation unit 86 estimates that the portable terminal device 14a exists outside the vehicle 12, and the transmission power adjustment unit 85 sets the transmission power to normal transmission power. The unit 82 transmits the packet signal with normal transmission power (S94). The transmission processing unit 82 transmits a packet signal including position information at a normal transmission frequency (S95). The reception processing unit 84 stops receiving packet signals broadcast from other terminal devices (S96).

If the reception intensity is greater than or equal to the set value in step S92 (N in S92), the estimation unit 86 estimates that the portable terminal device 14a is present in the vehicle 12, and the transmission power adjustment unit 85 sets the transmission power to lower than normal. Then, the transmission processing unit 82 transmits the packet signal with low transmission power (S98). The transmission processing unit 82 transmits a packet signal including position information at a lower frequency than usual (S99).

Next, a sixth modification will be described. The terminal device according to the sixth modification is also carried by the user and moved. When the portable terminal device according to the sixth modification is present in the building, the portable terminal device transmits the packet signal with lower transmission power than when the portable terminal device exists outside the building. Here, the portable terminal device estimates whether it exists in the building or outside the building from the reception intensity of the packet signal broadcast from the indoor wireless device. An indoor wireless device is installed in a building and provides various information toward a terminal device existing in the building. For example, indoor wireless devices are installed in buildings installed in highway service areas, gas stations, and the like. Moreover, you may install in other buildings where many people enter and exit, such as a convenience store, a restaurant, and a shopping store.

The indoor wireless device may be basically the same type as the terminal device of FIG. The indoor radio apparatus can be configured not to receive the packet signal from the base station apparatus 10 and not to transfer the packet signal. In this case, the configuration related to the function can be omitted, and wireless communication using only CSMA / CA is executed. Further, since the indoor wireless device is fixedly installed, a configuration unique to the mobile terminal such as a GPS receiver can be omitted.

The communication system 100 according to the sixth modification has a configuration in which an indoor wireless device is added to the communication system 100 in FIG. 1, and the base station device 10 is the same type as that in FIG. The in-vehicle terminal device is the same type as in FIG. 7, and the portable terminal device 14a is the same type as in FIG. Below, it demonstrates focusing on a difference.

The estimation unit 86 detects the reception intensity of the packet signal broadcast from the indoor wireless device, and estimates whether the portable terminal device 14a exists indoors or outdoors. As described above, since the indoor wireless device transmits a packet signal with transmission power having a reception range in the building, the estimation unit 86 determines whether or not the packet signal notified from the indoor wireless device is detected. It can be estimated whether the device 14a exists indoors or outdoors. If the packet signal can be detected, it can be estimated that the packet signal is present indoors.

Note that whether or not the transmission source of the packet signal is an indoor wireless device can be specified by referring to the transmission source type stored in the header of the MAC frame. When the transmission source type is a base station device, an in-vehicle terminal device, and a portable terminal device, the packet signal is not used for determining whether the portable terminal device 14a exists indoors.

The estimation unit 86 sets in the transmission processing unit 82, the reception processing unit 84, and the transmission power adjustment unit 85 whether the portable terminal device 14a is estimated to be present indoors or is estimated to be present outdoors.

The transmission processing unit 82 receives position information from a GPS receiver or the like, and stores the position information in the data payload of the MAC frame. The transmission processing unit 82 broadcasts and transmits a packet signal including the MAC frame at a predetermined timing. The transmission power adjustment unit 85 adjusts transmission power when a packet signal is transmitted by the transmission processing unit 82, the modem unit 54, the RF unit 52, and the antenna 50. Specifically, the transmission power adjustment unit 85 sets the transmission power when the portable terminal device 14a is estimated to be present indoors lower than the transmission power when it is estimated that the portable terminal device 14a is present outdoors.

When it is estimated that the portable terminal device 14a exists indoors, it can be said that the user carrying the portable terminal device 14a is in a safe position, and thus the necessity of notifying the vehicle of the presence is low. On the other hand, when it is estimated that the portable terminal device 14a exists outdoors, it is highly necessary to notify the vehicle located in the vicinity of the presence of a pedestrian carrying the portable terminal device 14a.

When it is estimated that the portable terminal device 14a exists indoors, the portable terminal device 14a can use the service provided by the indoor wireless device by the communication between the portable terminal device 14a and the indoor wireless device. . The generation unit 64 of the indoor wireless device generates a packet signal including a service menu provided to the portable terminal device 14a, and a transmission processing unit (not shown) of the indoor wireless device 0 notifies the packet signal. The service menu includes map information, position information, product information, coupons, questionnaires, and the like.

The reception processing unit 84 of the portable terminal device 14a receives the packet signal notified from the indoor wireless device, and the notification unit 70 displays the service menu included in the packet signal on the screen. A user carrying the portable terminal device 14a selects a menu. The generation unit 64 of the portable terminal device 14a generates a packet signal including the selection information, and the transmission processing unit 82 notifies the packet signal.

A reception processing unit (not shown) of the indoor wireless device receives the packet signal. The generation unit 64 of the base station apparatus 10 generates a packet signal including service information of a menu corresponding to the selection information. A transmission processing unit (not shown) of the indoor radio apparatus notifies the packet signal. The reception processing unit 84 of the portable terminal device 14a receives the packet signal, and the notification unit 70 displays the service information included in the packet signal on the screen. The exchange of information between the indoor wireless device and the portable terminal device 14a is executed by the above-described inter-vehicle communication.

The estimation unit 86 stops the reception process by stopping the reception processing unit 84 when it is estimated that the portable terminal device 14a exists outdoors. In the sixth modification as well, the stop of the reception process means that the data stored in the data payload of the packet signal is discarded without being processed. The reception processing unit 84 may stop the reception process of the packet signal regardless of the transmission source type, or may stop the reception process of the packet signal notified from another terminal device 14.

When the estimation unit 86 estimates that the portable terminal device 14a is present indoors, the transmission processing unit 82 of the portable terminal device 14a includes a packet signal that includes position information at a lower frequency than when estimated to be present outdoors. May be notified. When the user carrying the portable terminal device 14a is indoors, the necessity of notifying the vehicle of the presence is low.

Next, a seventh modification will be described. The terminal device according to the seventh modification is also carried by the user and moved. Hereinafter, a mode in which the terminal device is installed and used at a predetermined position in the vehicle is referred to as an in-vehicle device mode, and a mode in which the terminal device is carried by the user is referred to as a pedestrian terminal mode. Thus, the said terminal device is equipped with the function of both onboard equipment and a pedestrian terminal device. Hereinafter, in-vehicle equipment is a concept that includes the terminal device operating in the on-vehicle equipment mode in addition to the dedicated equipment. The pedestrian terminal device has a concept including the terminal device operating in the pedestrian terminal mode in addition to the dedicated machine.

The terminal device may be a dedicated machine having the functions of both the vehicle-mounted device and the pedestrian terminal device, or may be a smartphone, tablet, or car navigation device having both functions. Since the terminal device operates with a built-in battery, low power consumption is desired. On the other hand, in order to ensure the safety of the user, it is required to inform the vehicle of the location of the user by transmitting a packet signal. Furthermore, when the user installs the terminal device at a predetermined position in the vehicle, it is desired to operate in the same manner as the vehicle-mounted device.

In order to cope with these, the terminal device according to the seventh modification executes different reception processes depending on whether the terminal device exists in the vehicle or outside the vehicle. The communication system 100 according to the seventh modification is the same type as that in FIG. 1, the base station device 10 is the same type as that in FIG. 2, and the terminal device 14 is the same type as that in FIGS. It is. Below, it demonstrates focusing on a difference.

The terminal device 14 is installed in a folder or a docking station (hereinafter collectively referred to as a folder) when used in the vehicle 12. This folder is provided with a power supply terminal (not shown), and the connection portion 88 can receive power supply from this power supply terminal. When the estimation unit 86 detects that the connection unit 88 is connected to the power supply terminal, the estimation unit 86 estimates that the terminal device 14 is present in the vehicle 12, and detects that the terminal device 14 is not connected to the power supply terminal. Presumed to exist outside.

Note that the estimation unit 86 determines that the terminal device 14 is in the vehicle 12 depending on whether or not the casing of the terminal device 14 and the above-described folder are in physical contact, not whether or not the connection unit 88 is connected to the power supply terminal. Or existing outside the vehicle 12 may be estimated.

The estimation unit 86 sets the terminal device 14 to the vehicle-mounted device mode when it is estimated that the terminal device 14 exists in the vehicle 12, and sets the pedestrian terminal mode when it is estimated that the terminal device 14 exists outside the vehicle 12. The estimation unit 86 causes the reception processing unit 84 to execute different reception processes in the vehicle-mounted device mode and the pedestrian terminal mode. When the terminal device 14 exists outside the vehicle 12, the reception processing unit 84 performs simpler reception processing than when the terminal device 14 exists inside the vehicle 12. Specifically, when it is estimated that the terminal device 14 exists in the vehicle 12, the data stored in the packet signals from the base station device 10, the vehicle-mounted device, and the pedestrian terminal device are processed. On the other hand, when the terminal device 14 exists outside the vehicle 12, the data stored in the packet signal from the base station device 10 and the vehicle-mounted device is processed, but the data stored in the packet signal from the pedestrian terminal device is discarded. To do. That is, the data stored in the packet signal from the other terminal device outside the vehicle 12 is discarded.

When the terminal device 14 is carried by a pedestrian and is operating in the pedestrian terminal mode, the main target for avoiding the danger is a vehicle. Pedestrians are not the main target because it is difficult for pedestrians to have a big accident. Therefore, the terminal device 14 only needs to be able to acquire the position of the vehicle located in the vicinity of the pedestrian, and the request for acquiring the positions of other pedestrians located in the vicinity of the pedestrian is low.

FIG. 18 is a flowchart showing a processing procedure in the reception processing unit 84 according to the seventh modification. When the packet signal is received by the antenna 50, the RF unit 52, and the modem unit 54 (S100), the reception processing unit 84 determines whether the mode is the vehicle-mounted device mode or the pedestrian terminal mode (S102). When it is pedestrian terminal mode (pedestrian of S102), the reception processing unit 84 determines whether or not the transmission source type of the received packet signal is a pedestrian terminal device (S104). The transmission source type can be specified with reference to the header of the MAC frame input from the modem unit 54.

When the transmission source type is a pedestrian terminal device (Y in S104), the reception processing unit 84 discards the data payload of the packet signal without processing it (S108). When the transmission source type is the vehicle-mounted device or the base station device 10 (N in S104), application data is extracted from the data payload of the packet signal, and the application data is processed (S106). In step S102, when the in-vehicle device mode is set (on-vehicle in S102), the reception processing unit 84 extracts application data from the data payload of the received packet signal regardless of the transmission source type, and processes the application data ( S106).

Next, an eighth modification will be described. The terminal device according to the eighth modification also includes an in-vehicle device mode and a pedestrian terminal mode. The assumed road safety risk model differs between a vehicle equipped with an onboard device and a pedestrian carrying a pedestrian terminal device. In the case of a vehicle, a case where the vehicle is primarily harmed by another vehicle, a case where the vehicle is harmed, or a case where the vehicle is harmed by a pedestrian is assumed. In the case of pedestrians, there are cases where the vehicle is primarily harmed.

As described above, since the risk assumed in the vehicle-mounted device mode and the pedestrian terminal mode is different, the terminal device executes different risk determination processes in both modes. The communication system 100 according to the eighth modification is the same type as that in FIG. 1, the base station device 10 is the same type as that in FIG. 2, and the terminal device 14 is the same type as that in FIGS. It is. Below, it demonstrates focusing on a difference.

The estimation unit 86 causes the reception processing unit 84 to execute different risk determination processes in the vehicle-mounted device mode and the pedestrian terminal mode. The reception processing unit 84 acquires position information from the data payload of the packet signal received from the base station device 10, the vehicle-mounted device, or the pedestrian terminal device. The reception processing unit 84 determines whether to notify the presence of a vehicle or a pedestrian specified by the position information by executing a risk determination process.

The danger area setting range differs between the danger determination process in the onboard mode (hereinafter referred to as the first danger determination process) and the danger determination process in the pedestrian terminal mode (hereinafter referred to as the second danger determination process). In the case of a vehicle, the danger level of the area in the traveling direction is high, and the danger level is relatively low in the left and right and rear areas of the vehicle. In the case of a vehicle, it is difficult to change the traveling direction suddenly, and a driver who performs such driving is rare. Therefore, the danger area (hereinafter referred to as the first danger area) in the first danger determination process is set to a shape in which the traveling direction of the vehicle is relatively swollen relative to other directions.

In the case of pedestrians, the speed of travel is slow, so it cannot be said that the danger level of the area in the direction of travel is high. For a pedestrian, the vehicle may rush from either direction. Therefore, the danger area (hereinafter referred to as the second danger area) in the second danger determination process is set in a circle around the pedestrian.

When the reception processing unit 84 receives position information from the vehicle-mounted device or the pedestrian terminal device located in the first danger area in the vehicle-mounted device mode, the reception processing unit 84 basically notifies the driver of the presence of the position information. When position information is received from an onboard device or a pedestrian terminal device located outside, the presence is not notified.

When receiving position information from the vehicle-mounted device located in the second danger area in the pedestrian terminal mode, the reception processing unit 84 basically notifies the pedestrian of the presence and is located outside the second danger area. When location information is received from the OBE, the presence is not notified. In addition, the reception via the base station apparatus 10 is also included in the reception of the positional information from the vehicle-mounted device or the pedestrian terminal device.

Even if the reception processing unit 84 receives position information from the vehicle-mounted device or the pedestrian terminal device located in the first danger area in the vehicle-mounted device mode, the reception processing unit 84 does not notify the presence unconditionally, Whether or not to notify may be determined depending on whether or not the above is satisfied. The traveling direction and moving speed included in the position information can be used for the condition.

For example, when position information is received from the vehicle-mounted device, the traveling direction included in the position information is referred to and it is determined whether the vehicle on which the vehicle-mounted device is mounted approaches or leaves the vehicle. In addition, what is necessary is just to observe the time change of the distance between vehicles when the advancing direction cannot be acquired. When you leave your own vehicle, you are not notified of the presence of that vehicle. Also, even when the vehicle on which the vehicle-mounted device is mounted approaches the own vehicle, if the traveling direction of the approaching vehicle and the traveling direction of the own vehicle are substantially opposite, The coming vehicle is determined as an oncoming vehicle, and the presence of the vehicle is not notified. Further, when position information is received from the vehicle-mounted device, the moving speed included in the position information is referred to, and if the speed of the vehicle on which the vehicle-mounted device is mounted is slower than the set value, the presence of the vehicle is not notified.

Even if the reception processing unit 84 receives the position information from the vehicle-mounted device located in the second danger area in the pedestrian terminal mode, the reception processing unit 84 does not notify the existence unconditionally but satisfies the predetermined condition. The presence or absence of notification may be determined depending on the above. Similar to the vehicle-mounted device mode, the traveling direction included in the position information can be used for the condition.

For example, when position information is received from the vehicle-mounted device, the traveling direction included in the position information is referenced to determine whether the vehicle on which the vehicle-mounted device is mounted approaches or leaves the pedestrian. When leaving, the presence of the vehicle going away is not notified.

FIG. 19 is a diagram for explaining the first risk determination process and the second risk determination process. The first vehicle 12a, the second vehicle 12b, the third vehicle 12c, the fourth vehicle 12d, the fifth vehicle 12e, the sixth vehicle 12f, the seventh vehicle 12g, and the eighth vehicle 12h are each equipped with a terminal device (not shown). . Each of the first pedestrian 16a and the second pedestrian 16b carries a terminal device (not shown).

The first vehicle 12a, the second vehicle 12b, the third vehicle 12c, and the fourth vehicle 12d are traveling from “South” toward “North”. The fifth vehicle 12e, the sixth vehicle 12f, and the seventh vehicle 12g are traveling from “north” to “south”. The eighth vehicle 12h is traveling from “west” to “east” and is traveling toward the T-junction. The first pedestrian 16a and the second pedestrian 16b are located on the shoulders of the priority road, and in particular, the first pedestrian 16a is located near the T-shaped road.

The reception processing unit 84 of the terminal device mounted on the first vehicle 12a sets the first danger area 220. In the first danger area 220, there are a second vehicle 12b, a fourth vehicle 12d, a fifth vehicle 12e, a sixth vehicle 12f, a seventh vehicle 12g, an eighth vehicle 12h, and a first pedestrian 16a. The reception processing unit 84 of the terminal device mounted on the first vehicle 12a includes the second vehicle 12b, the fourth vehicle 12d, the fifth vehicle 12e, the sixth vehicle 12f, the seventh vehicle 12g, the eighth vehicle 12h, and the first walking. When the positional information is received from any of the terminal devices mounted on or carried by the person 16a, the presence information is displayed on the display or the voice guidance is output, or both.

Since the first vehicle 12a, the fourth vehicle 12d, and the second vehicle 12b have the same traveling direction, the most likely accident risk is a rear-end collision. Therefore, when the reception processing unit 84 of the terminal device mounted on the first vehicle 12a acquires position information from the terminal device mounted on the fourth vehicle 12d or the second vehicle 12b, The existence of the fourth vehicle 12d or the second vehicle 12b may be notified only when the distance between the four vehicles 12d or the distance between the first vehicle 12a and the second vehicle 12b is narrowed.

The fifth vehicle 12e, the sixth vehicle 12f, and the seventh vehicle 12g are oncoming vehicles of the first vehicle 12a. Unless there is a large change in the traveling direction of the fifth vehicle 12e, the sixth vehicle 12f, and the seventh vehicle 12g, it can be said that the possibility of a collision with the first vehicle 12a is low. Therefore, when the reception processing unit 84 of the terminal device mounted on the first vehicle 12a acquires position information from the terminal devices mounted on the fifth vehicle 12e, the sixth vehicle 12f, and the seventh vehicle 12g, the presence of the presence information. Notification may be omitted.

Since the eighth vehicle 12h is heading toward the T-junction, when the reception processing unit 84 of the terminal device mounted on the first vehicle 12a acquires position information from the terminal device mounted on the eighth vehicle 12h, Notify existence. When the eighth vehicle 12h moves away from the T-junction, the presence notification may be omitted.

The reception processing unit 84 of the terminal device carried by the first pedestrian 16a sets the second danger area 222. In the second danger area 222, there are a fourth vehicle 12d, a sixth vehicle 12f, a seventh vehicle 12g, and an eighth vehicle 12h. The reception processing unit 84 of the terminal device carried by the first pedestrian 16a obtains position information from any of the terminal devices mounted on the fourth vehicle 12d, the sixth vehicle 12f, the seventh vehicle 12g, and the eighth vehicle 12h. When received, the presence is displayed on the display, voice guidance is output, or the casing is vibrated. Two or more of them may be executed.

The larger the area of the second danger area 222, the higher the traffic safety, but the load of the reception process increases and the consumption of the built-in battery becomes faster. The designer sets the area of the second danger area 222 in consideration of the trade-off. There is a view that the area of the second danger area 222 may be smaller than the area of the first danger area 220 because the vehicle side is primarily obligated to avoid a collision between the pedestrian and the vehicle.

FIG. 20 is a flowchart showing a processing procedure in the reception processing unit 84 according to the eighth modification. Receiving processing part 84 will acquire position information transmitted from other terminal units (S110), and will judge whether it is onboard equipment mode or pedestrian terminal mode (S112). When it is on-vehicle equipment mode (vehicle installation of S112), the 1st danger judgment processing is performed (S114). When it is a pedestrian terminal mode (pedestrian of S112), a 2nd danger determination process is performed (S116).

The reception processing unit 84 determines whether or not to notify the driver or pedestrian of the presence of the vehicle or pedestrian specified by the received position information as a result of the first risk determination process or the second risk determination process ( S118). If it is determined that notification is necessary (Y in S118), the reception processing unit 84 notifies the presence of the vehicle or pedestrian (S120). If it is determined that the notification is unnecessary (N in S118), the process in step S120 is skipped.

Next, a ninth modification will be described. The terminal device according to the ninth modification also includes an in-vehicle device mode and a pedestrian terminal mode. The communication system 100 according to the ninth modification is the same type as in FIG. 1, the base station apparatus 10 is the same type as in FIG. 2, and the terminal apparatus 14 is the same type as in FIG. 7 and FIG. It is. Below, it demonstrates focusing on a difference.

The estimation unit 86 causes the transmission processing unit 82 to execute different transmission processes in the vehicle-mounted device mode and the pedestrian terminal mode. For example, the transmission processing unit 82 executes transmission processing with different transmission frequencies in the vehicle-mounted device mode and the pedestrian terminal mode. Specifically, the transmission process in the pedestrian terminal mode is executed at a lower frequency than the transmission process in the vehicle-mounted device mode.

The transmission processing unit 82 receives position information from a GPS receiver or the like, and stores the position information in the data payload of the MAC frame. The transmission processing unit 82 broadcasts and transmits a packet signal including the MAC frame at a predetermined timing. The transmission frequency is different between the vehicle-mounted device mode and the pedestrian terminal mode.

FIG. 21 is a flowchart showing a processing procedure in the transmission processing unit 82 according to the ninth modification. The transmission process part 82 determines whether it is onboard equipment mode or pedestrian terminal mode (S130). When it is pedestrian terminal mode (pedestrian of S130), transmission processing part 82 changes the transmission frequency of position information to low (S132). If it is in the vehicle-mounted device mode (vehicle mounted in S130), the process in step S132 is skipped. For example, it may be transmitted once every 100 msec when the transmission frequency of the position information is normal, or once every 500 msec or once every 1 min when the frequency is low. The transmission processing unit 82 transmits the position information with the set transmission frequency (S134).

Next, a tenth modification will be described. The terminal device according to the tenth modification is also carried by the user and moved. Since the terminal device operates with a built-in battery, low power consumption is desired. On the other hand, ensuring the safety of the user is also required.

To cope with this, the terminal device according to the tenth modification executes transmission processing and reception processing when carried by the user, and at least one of transmission processing and reception processing when not carried by the user To stop. The communication system 100 according to the tenth modification is the same type as that in FIG. 1, the base station device 10 is the same type as that in FIG. 2, and the terminal device 14 is the same type as that in FIGS. It is. Below, it demonstrates focusing on a difference.

The acquisition unit 72 acquires position information from a GPS receiver (not shown). The estimation unit 86 estimates whether or not the terminal device 14 is in a carried state from the change in position information acquired by the acquisition unit 72. When there is a change in position, the estimation unit 86 estimates that the vehicle is in a carried state. When there is no change in position, the estimation unit 86 estimates that the vehicle is not in the carried state but is in a state where it is placed somewhere.

Further, the acquisition unit 72 may acquire vibration information from an acceleration sensor (not shown). The estimation unit 86 estimates whether or not the terminal device 14 is in the carried state from the vibration information acquired by the acquisition unit 72. When the vibration component is detected, the estimation unit 86 estimates that the device is in the carried state, and when the vibration component is not detected, the estimation unit 86 estimates that the device is not in the carried state but is placed somewhere. When the terminal device 14 is a dedicated machine for the pedestrian terminal device and the terminal device 14 is estimated to be present in the vehicle 12 by the same processing as the first to third and seventh to ninth modifications, The estimation unit 86 may determine that it is not in the carried state. When the terminal device 14 is present in the traveling vehicle 12, position changes and vibration components are detected, but a situation where a pedestrian terminal device not operating as a vehicle-mounted device is present in the vehicle 12 is indoors. It is a situation close to the situation that exists, and both can be handled in the same way.

When estimating that the terminal device 14 is in the carried state, the estimation unit 86 operates the transmission processing unit 82 and the reception processing unit 84 to execute transmission processing and reception processing. On the other hand, when the estimation unit 86 estimates that it is not in the carried state, the estimation unit 86 stops one of the transmission processing and the reception processing by stopping one of the transmission processing unit 82 and the reception processing unit 84. For example, the estimation unit 86 operates only the transmission processing unit 82 and stops the reception processing unit 84. Note that the reverse may be possible.

Note that, similarly to the seventh to ninth modifications, the estimation unit 86 may cause the reception processing unit 84 to execute different reception processes depending on whether or not the terminal device 14 is in the carried state. In addition, the estimation unit 86 may cause the reception processing unit 84 to execute different risk determination processes depending on whether or not the terminal device 14 is in the carried state. In addition, the estimation unit 86 may cause the transmission processing unit 82 to execute different transmission processing depending on whether or not the terminal device 14 is in the carried state. In any case, the case of being in the vehicle may be read when the case is in the carried state and the case of being outside the vehicle is not read in the case of the carried state.

According to the embodiment of the present invention, since the change of the area is notified, it is possible to notify the driver of the importance set for the traveling area. In addition, since the driver is informed of the importance set for the traveling area, the driver can be alerted. In addition, since the driver is alerted, the probability of occurrence of a collision accident can be suppressed. Also, since priority is given to the area according to the importance of the packet signal to be notified, important information can be transmitted with priority. In addition, since the priority with respect to the area is defined according to the quality of the received signal, transmission processing according to the quality can be realized. In addition, since the priority with respect to the area is defined according to the distance from the base station apparatus, transmission processing according to the distance can be realized. Moreover, since the notification mode is changed according to the area, the area can be recognized accurately.

In the general period, terminal devices existing in the first area around the base station apparatus can broadcast packet signals. In the priority period, terminal apparatuses existing in the second area surrounding the first area broadcast packet signals. Since it is possible, the priority of communication in the second area can be improved. Moreover, since the priority of communication in the second area is improved, it is possible to improve the reception probability of the packet signal broadcast from the terminal device existing in the second area. Further, since the reception probability of the packet signal broadcast from the terminal device existing in the second area is improved, important data can be transmitted with priority. Also, since the first arrangement and the second arrangement can be switched, it is possible to switch between improving the communication priority in the first area and improving the communication priority in the second area. In addition, since the priority of communication in the first area can be switched to the priority of communication in the second area, the area to be prioritized can be selected according to the intersection. In addition, since the selection of the first arrangement or the second arrangement is indicated by the priority area identifier, the processing can be simplified.

Since received power is used to distinguish between the first area and the second area, a range in which the propagation loss is within a predetermined level can be defined as the first area. In addition, since the range in which the propagation loss is within a predetermined level is defined in the first area, the vicinity of the center of the intersection can be used as the first area. In addition, since the time division multiplexing by slots is executed in the priority period, the error rate can be reduced. Moreover, since CSMA / CA is performed in a general period, the number of terminal devices can be adjusted flexibly.

Also, since the subframe used by the other base station apparatus is specified based on the packet signal received from the terminal apparatus as well as the packet signal directly received from the other base station apparatus, The frame identification accuracy can be improved. In addition, since the accuracy of identifying subframes in use is improved, the probability of collision between packet signals transmitted from the base station apparatus can be reduced. Moreover, since the collision probability between packet signals transmitted from the base station apparatus is reduced, the terminal apparatus can accurately recognize the control information. Further, since the control information is accurately recognized, the road and vehicle transmission period can be accurately recognized. Further, since the road and vehicle transmission period is accurately recognized, the collision probability of the packet signal can be reduced.

In addition, since a subframe other than the currently used subframe is used preferentially, it is possible to reduce the possibility of transmitting a packet signal at a timing overlapping with packet signals from other base station apparatuses. Further, when any subframe is used by another base station apparatus, a subframe with low received power is selected, so that the influence of packet signal interference can be suppressed. Further, since the received power of the terminal device is used as the received power from another base station device that is the transmission source of the control information relayed by the terminal device, the received power estimation process can be simplified.

Also, since it is estimated whether or not it is present in the vehicle depending on whether or not it is battery-driven, it is possible to accurately specify the case where an operation with low power consumption is necessary. Further, since the transmission process and the reception process are executed when the vehicle is present in the vehicle, the same process as that of the in-vehicle terminal device can be executed. Moreover, when it exists out of a vehicle, since one of a transmission process and a reception process is stopped, power consumption can be reduced. Moreover, since it only performs a transmission process when it exists outside a vehicle, it can notify an existing position, reducing power consumption.

Also, since the location is notified, the presence can be informed and safety can be ensured. Further, since the terminal device operates with low power consumption, the function of the terminal device can be installed in a mobile phone terminal or the like. Further, since the function of the terminal device is mounted on a mobile phone terminal or the like, the communication system can be easily spread. Moreover, even if it is battery-powered, if it enters into a predetermined area, since a transmission process and a reception process will be performed, the process similar to the vehicle-mounted terminal device can be performed as needed. Moreover, when it exists outside an area, since one of a transmission process and a reception process is stopped, power consumption can be reduced.

Also, since the inside and outside of the area are only specified, processing can be simplified. Moreover, since the movement from outside the area to the inside of the area is detected, it is possible to notify the improvement of the risk of a collision accident caused by approaching the intersection.

Also, when the portable terminal device is present in the vehicle, the battery can be saved by transmitting the packet signal with lower power than when the portable terminal device is present outside the vehicle. Further, when the portable terminal device is present in the vehicle, the battery can be saved by notifying the position information less frequently than when the portable terminal device is present outside the vehicle. In addition, when a portable terminal device exists in a vehicle, since a user will also exist in a vehicle, the necessity to notify the presence to another vehicle becomes low. Further, when the portable terminal device exists outside the vehicle, the battery can be saved by stopping the reception process.

Also, the convenience of passengers can be improved by using at least part of the services provided by the in-vehicle terminal device in the vehicle. Moreover, the convenience of the pedestrian who carries the portable terminal device can be improved by using the service provided by each in the radio wave range of the building and the roadside unit.

Also, in a terminal device having an on-vehicle device mode and a pedestrian terminal mode, processing suitable for the mode can be performed by changing the content of reception processing or the content of transmission processing depending on the mode. In the pedestrian terminal mode, power consumption can be reduced by simplifying reception processing and transmission processing. Moreover, the process suitable for each danger model of a vehicle and a pedestrian is attained by changing a danger determination process with onboard equipment mode and pedestrian terminal mode.

Further, when the terminal device is carried by the user, the transmission process and the reception process are executed, so that the safety of the user can be improved. When the terminal device is not carried by the user, at least one of the transmission process and the reception process is stopped, so that power consumption can be reduced. When the terminal device is not carried by the user, the user is in a safe place or away from the terminal device. In the former case, it is not necessary to improve the safety, and in the latter case, the effectiveness of the process for improving the safety is not ensured. Therefore, priority is given to reducing power consumption.

The present invention has been described based on the embodiments. 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 first and second modified examples of the present invention, when the estimation unit 86 is estimated to exist outside the vehicle 12 or is estimated to exist outside a predetermined area, the transmission processing unit 82 and the reception processing unit 84 One of them is stopped. However, the present invention is not limited thereto, and for example, the estimation unit 86 may stop both the transmission processing unit 82 and the reception processing unit 84 in the above case. According to the first and second modifications, power consumption can be reduced.

The outline of one embodiment of the present invention is as follows. A wireless device according to an aspect of the present invention is a wireless device that performs communication with another wireless device, and includes a communication unit that performs transmission processing and reception processing, and the wireless device is present in the vehicle. An estimator that estimates whether it exists outside. When the estimation unit estimates that the wireless device is present in the vehicle, the communication unit transmits a signal with lower transmission power than when the wireless device exists outside the vehicle.

According to this aspect, when it is estimated that the wireless device is present in the vehicle, the power consumption of the wireless device can be reduced by transmitting a signal with lower transmission power than when the wireless device is present outside the vehicle.

The communication unit may transmit a signal at a lower frequency when the estimation unit estimates that the wireless device is present in the vehicle than when the communication unit exists outside the vehicle. According to this, the power consumption of the wireless device can be further reduced.

The communication unit may execute the transmission process and the reception process when the estimation unit estimates that the wireless device is present in the vehicle, and may stop the reception process when it is estimated that the wireless device exists outside the vehicle. Since the transmission process and the reception process are executed when the vehicle is present in the vehicle, the same process as that of the in-vehicle terminal device can be executed. Further, when the vehicle is present outside the vehicle, the transmission process is executed and the reception process is stopped, so that the presence position can be notified while reducing power consumption.

Another aspect of the present invention is also a wireless device. This device is a wireless device that performs communication with other wireless devices, and the first area and the second area are defined as areas having different priorities from the first area to the second area. A detection unit that detects movement; a communication unit that changes communication processing defined in the first area to communication processing defined in the second area when the detection unit detects movement; and Or an estimation unit that estimates whether the vehicle exists outside the vehicle. The communication unit executes different reception processes depending on whether the wireless device estimated by the estimation unit is present inside the vehicle or outside the vehicle.

According to this aspect, it is possible to optimize the reception process by making the reception process different depending on whether the wireless device exists in the vehicle or outside the vehicle.

The communication unit may discard the data received from another wireless device existing outside the vehicle when the estimating unit estimates that the wireless device exists outside the vehicle. According to this, the load on the wireless device can be reduced.

Still another aspect of the present invention is also a wireless device. This device is a wireless device that performs communication with other wireless devices, and the first area and the second area are defined as areas having different priorities from the first area to the second area. A detection unit that detects movement; a communication unit that changes communication processing defined in the first area to communication processing defined in the second area when the detection unit detects movement; and Or an estimation unit that estimates whether the vehicle exists outside the vehicle. The communication unit executes the transmission process at different transmission frequencies depending on whether the wireless device estimated by the estimation unit is present inside the vehicle or outside the vehicle.

According to this aspect, it is possible to optimize the transmission process by changing the transmission frequency depending on whether the wireless device exists in the vehicle or outside the vehicle.

When the estimation unit estimates that the wireless device exists outside the vehicle, the communication unit may execute the transmission process at a lower frequency than when the communication unit exists inside the vehicle. According to this, the power consumption of the wireless device can be reduced.

Still another aspect of the present invention is also a wireless device. This device is a wireless device that performs communication with other wireless devices, and the first area and the second area are defined as areas having different priorities from the first area to the second area. A detection unit that detects movement; a communication unit that changes communication processing defined in the first area to communication processing defined in the second area when the detection unit detects movement; and Or an estimation unit that estimates whether the vehicle exists outside the vehicle. The communication unit performs transmission processing and reception processing when the estimation unit estimates that the wireless device is present in the vehicle, and performs transmission processing and reception processing when the estimation unit estimates that the wireless device is present outside the vehicle. Stop at least one of the

According to this aspect, since the transmission process and the reception process are executed when the vehicle is present in the vehicle, the same process as that of the in-vehicle terminal device can be executed. Moreover, when it exists outside a vehicle, since at least one of a transmission process and a reception process is stopped, power consumption can be reduced.

When the movement is detected by the detection unit, a notification unit that notifies the change of the area may be further provided. According to this, since the change of the area is notified, the importance set for the traveling area can be notified to the user.

Still another aspect of the present invention is also a wireless device. This device is a wireless device that performs communication with other wireless devices, and when the wireless communication device estimates that the wireless device is in a carried state and the estimating portion is in a carried state, transmission processing is performed. And a communication unit that executes reception processing. The communication unit stops at least one of the transmission process and the reception process when it is estimated that the estimation unit is not in the carried state.

According to this aspect, when the wireless device is in the carried state, the transmission process and the reception process are executed, so that a sufficient function can be exhibited. Further, when not in the carried state, the power consumption can be reduced because at least one of the transmission process and the reception process is stopped.

10 base station devices, 12 vehicles, 14 terminal devices, 20 antennas, 22 RF units, 24 modulation / demodulation units, 26 processing units, 30 control units, 40 frame definition units, 42 selection units, 44 detection units, 46 generation units, 48 settings Unit, 50 antenna, 52 RF unit, 54 modulation / demodulation unit, 56 processing unit, 58 control unit, 60 timing identification unit, 64 generation unit, 66 extraction unit, 70 notification unit, 72 acquisition unit, 80 network communication unit, 82 transmission processing Part, 84 reception processing part, 85 transmission power adjustment part, 90 transfer determination part, 92 selection part, 94 carrier sense part, 100 communication system.

The present invention can be used for a portable terminal device.

Claims

A wireless device that performs communication with another wireless device,
A communication unit that executes transmission processing and reception processing;
An estimation unit that estimates whether the wireless device exists in the vehicle or outside the vehicle,
The communication unit, when the estimation unit estimates that the wireless device is present in the vehicle, transmits a signal with lower transmission power than when the wireless device is present outside the vehicle.
The wireless device according to claim 1, wherein the communication unit transmits a signal at a lower frequency when the estimation unit estimates that the wireless device is present in the vehicle than when the communication unit exists outside the vehicle.
The communication unit performs a transmission process and a reception process when the estimation unit estimates that the wireless device is present in the vehicle, and stops the reception process when it is estimated that the wireless device exists outside the vehicle. The wireless device according to claim 1 or 2.
A wireless device that performs communication with another wireless device,
As the areas having different priorities, a first area and a second area are defined, and a detection unit that detects movement from the first area to the second area;
A communication unit that changes communication processing defined in the first area to communication processing defined in the second area when movement is detected in the detection unit;
An estimation unit that estimates whether the wireless device is present inside the vehicle or outside the vehicle,
The radio apparatus according to claim 1, wherein the communication unit executes different reception processes depending on whether the radio apparatus estimated by the estimation unit exists in a vehicle or outside the vehicle.
The wireless communication according to claim 4, wherein the communication unit discards data received from another wireless device existing outside the vehicle when the estimating unit estimates that the wireless device exists outside the vehicle. apparatus.
A wireless device that performs communication with another wireless device,
As the areas having different priorities, a first area and a second area are defined, and a detection unit that detects movement from the first area to the second area;
A communication unit that changes communication processing defined in the first area to communication processing defined in the second area when movement is detected in the detection unit;
An estimation unit that estimates whether the wireless device is present inside the vehicle or outside the vehicle,
The radio apparatus according to claim 1, wherein the communication unit executes transmission processing at different transmission frequencies depending on whether the radio apparatus estimated by the estimation unit is present in the vehicle or outside the vehicle.
The wireless device according to claim 6, wherein when the estimating unit estimates that the wireless device is present outside the vehicle, the communication unit executes transmission processing at a lower frequency than when the communication unit is present inside the vehicle.
A wireless device that performs communication with another wireless device,
As the areas having different priorities, a first area and a second area are defined, and a detection unit that detects movement from the first area to the second area;
A communication unit that changes communication processing defined in the first area to communication processing defined in the second area when movement is detected in the detection unit;
An estimation unit that estimates whether the wireless device is present inside the vehicle or outside the vehicle,
The communication unit performs transmission processing and reception processing when the estimation unit estimates that the wireless device is present in the vehicle, and performs transmission processing when the estimation unit estimates that the wireless device is outside the vehicle. And at least one of the reception processes is stopped.
The wireless device according to any one of claims 4 to 8, further comprising a notification unit that notifies a change of an area when movement is detected by the detection unit.
A wireless device that performs communication with another wireless device,
An estimation unit for estimating whether the wireless device is carried;
When it is estimated that the estimation unit is in a carried state, a communication unit that performs transmission processing and reception processing,
The communication unit stops at least one of a transmission process and a reception process when the estimation unit estimates that the estimation unit is not in a carried state.