" NUNCE "
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`JPD and NPR are not rwpansibfie for any damages caused by {he use of this twnsiafim.
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`1. This document has been tmnsiated by commier. So the iransiaiiém may mi reflect: the mgmai prefisehr.
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`2. N" Shim 3 ward which mama: be immiaied.
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`3. in the drawings. any 11mg are nut {tansisfled
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`Pubficafion Number
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`JP200823301 TA
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`Bibfiograghy
`
`{1'8} {Pabficafim cmmtry] JP
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`{12'} {Kind of official gazette} A
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`{1 1} {Fuhficafion number} 200823301?
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`{423} {Gate 01‘ pumicatien {3f appiicafian} 20081002
`
`{54) {T1013 of the inventicn} RAD’EO COMMUMCATEON APPARATUS AND ROAD-
`
`VEHiCLE COMMUNECATEON SYSTEM
`
`{51'} {intematinnai Patent C§assificationj
`
`G018
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`80813
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`3.546
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`1309
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`{2006.01 }
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`{2000.01}
`
`H048
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`H01Q
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`W20
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`1352
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`{2000.01 }
`
`{2008.01}
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`H0112}
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`211’28
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`{2008.01}
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`{F3}
`
`G013
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`SE46
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`H048
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`7728
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`@0813
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`1,108
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`H01Q
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`1352
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`H0112} 21:28
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`H
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`F
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`{21'} {Appficafian number} 200?0T8T51
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`{22} {Fiiing date} EU'UTU323
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`{7’1} {Appficant}
`
`{Name} TOYOTA ENFOTECHNQLQGY CENTER CO LTD
`
`{J2} {inventcr}
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`{F011 name} URAYAMA H1ROSH§
`
`{Them-e eerie {referencejy}
`
`5H1 80
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`53021
`
`

`

`$848
`
`fiKfiS?
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`{F—term {reference} }
`
`5H1 88MB“?
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`5H1 808834
`
`fii—H’ SGCC"! 2
`
`5 Hi BDLH 5
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`SJGZ'i'AADS
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`5&821 M88
`
`33821 M1 2
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`33821 A801
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`$3021 SAGE!
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`53021 PAS?!
`
`5&821 HAOS
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`5&821 HA1 {3
`
`$38.21 3m U
`
`EMSAAM
`
`EMSABW' Ci
`
`EJMSUAQB
`
`SKBEYAAM
`
`SKQSTBBN
`
`SKQGTDDM
`
`5K967EE82
`
`fiKfiS? EEBS
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`5Kfl87GGU‘?
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`SKBEYKKGZ
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`SKQGTKKOS
`
`3K967§<K1 T
`
`Abstract
`
`{5?} {Overview}
`
`PROBLEM TO BE SDLVED: Tc: prawns a nadir; mmmnné‘cation techneiagy napabie 0f
`
`detecting the arri‘vai {inaction 0f 3 venwie with a simpie methnd.
`
`SGLURUN: This radio communicafim apparatus for pefinrming radio enmmimicafion
`
`between it and 0n—vehic§e terminai comprises a péurafity of receiving antennas far
`
`receiving a known signai transmitted fnam the o-n—vehicie termina§, a posifion esfimafiing
`
`

`

`means for estimating: the azimuth of the en-vehioie tenninai based on the phase
`
`difference of the known signai received by the pinraiity of receiving antennas, a travei
`
`direction estimating means for estimating whether the on-vehicie terminai aooroaches or
`
`separates from ene‘s own device based on frequency transition of the known signai
`
`received by the ninraiity of receiving antennas, and a determining means for determining
`
`whether radio communication with the on-vehicie terminai is oertormed based on the
`
`estimation resoit by the position estimating means and travei direction estimating means.
`
`
`Ciaim
`
`{Patent Ciaims]
`
`{Ciaim t}
`
`A Wireiess communication device performs tvireiess communication with an in-vehicie
`
`tenninai.
`
`A pidraiity of receiving antennas for receiving a known signai transmitted from the on-
`
`vehicie terminai ;
`
`A position estimation means for estimating an azimuth of the on—vehicie terminai based
`
`on a phase ditierence of the known signai received at the oiuraiity of receotion antennas ;
`
`A traveiing direction estimating means for estimating whether the on—vehicie terminai is
`
`annroaching or away trorn the vehicie based on the frequency deviation of the known
`
`signai received at the pidraiitv oi receiving antennas ;
`
`A determination means for determining whether or not
`
`to perform wireiess
`
`communication with the in-vehicie terminai based on an estimation resuit by the position
`
`estimation means and the travei direction estimation means ;
`
`A wireiess communication device comprising :.
`
`{Ciaim 2}
`
`The wireiess communication device according to ciairn 1, wherein the reception
`
`antennas are directionai antennas, and each of the reception antennas has directivity in
`
`a different direction.
`
`{Ciairn 3}
`
`The radio communication device has shieiding means for shie-iding radio waves.
`
`Each of the piuraiity of receiving antennas has directivity to a different direction by
`
`shieiding radio waves from a predetermined direction by the shieiding means.
`
`The wireiess communication device according to ciaim “i, wherein the wireiess
`
`communication device incindes :.
`
`{Ciairn 4}
`
`The shieiding means is a ooiygonat coiumnar or cyiindricsi radio wave absorber.
`
`

`

`The piuraiity of receiving antennas are disperse-ti ciese tn the radie wave absorber.
`
`The wireiess communication device ascending ta ctaim 3, wherein the wireiess
`
`cemmunieatien device inciudes :.
`
`{Ciaim 5}
`
`The wireiess eemmunieetien device is instaited at an intersectienm
`
`The piuraiity of receiving antennas has directivity toward a read directinn.
`
`The determinatien unit determines that
`
`the in-vehicte terminai nerierms wireiess
`
`cemmunicatien with the in-vehicte terminai when the in—vehieie terminai aeereaches the
`
`G‘M'i apparatus tram a predetermined react directien.
`
`A Wireiess cemmunieatien device ascending te any at eiairns “i to 4.
`
`{Ciaim 6}
`
`The road-te-vehicie cemmunieatien system hertenns Wireiess cemmunieatien between
`
`a read-side machine and an en-vehicie terminai.
`
`The in-vehicie terminat inciudes 1
`
`Transmitting means for transmitting a knewn signai
`
`it ”“2
`
`The aterementiened read-side machine
`
`A nintaiity of receiving antennas tor receiving the knewn signai ;
`
`A hesitien estimatien means fer estimating an azimuth of the en-vehicte terminai based
`
`en a phase difference at the knewn Signet received at the nintaiity at recentien antennas ;
`
`A traveiing direction estimating means for estimating whether the en—vehieie tenninai is
`
`appreaching er away from the roadside machine based on a frequency deviation of the
`
`knewn signai received at the hinraiity at receiving antennas ;
`
`A detenninatien means for determining whether er net
`
`in perfen‘n wireiess
`
`cemmunicatien with the in-vehicte terminai based on an estimation resuit by the position
`
`estimation means and the travei directien estimatien means ;
`
`The “{ing} communicatien system between read and car.
`
`Uescrigtion
`
`{Detaiied descriptien oi the inventien}
`
`{'i'echnieat fieid}
`
`{000 i}
`
`The present invention reiates to a radie eemmunicatien techneiegy and, mere particuiariy,
`
`te a radie communicatien techneiegy canahie at detecting an arrivai direction at a vehieie.
`
`{Backgreund of the inventien}
`
`

`

`{0002}
`
`Recentiy, wireiess communication devices are mounted on vehicies, and wiretess
`
`communication is performed between venicies or between vehictes. An exsrhpie of such
`
`wireiess communication is a safe driving support system for notifying intorn'iation about
`
`a vehicie which is not viewed on a road with poor visibiiity such as an intersection and a
`
`curve, in such a system, information required by a certain vehicie is information about a
`
`vehicie directed toward the vehicie. in other words, depending on the direction of travei
`
`of the vehicte. the information about the vehicie is required or not. Accordingiy, it is not
`
`necessary to receive and process unnecessary information it the direction of travei of
`
`another vehicie is known.
`
`{0003}
`
`in this way. in the inter-vehicie communication and the road-to—vehicie communication.
`
`each wireiess communication device can communicate with oniy the necessary terminai
`
`oy grasping the position and the traveiing direction of the surrounding terminai. Thus, it
`
`is possihie to improve reiiahiiity of communication and reduce unnecessary radio wave
`
`radiation. Further. by iirniting the communication area by the adaptive array technoiogy,
`
`it is possihie to suppress unnecessary radio wave radiation.
`
`{0004}
`
`Accordingiy. a technique has been pronosed in which each terminai periodicaiiy
`
`transmits GPS position intormation, a terminai ii), a speed vector, an acceieration vector.
`
`and the iiite to the surroundings. in Patent Document 1 , the vehicie transmits the traveiing
`
`information obtained irom the GPS and the vehicie speed sensor together with the
`
`terminai it), so that the traveiing information of the surrounding vehicie can be grasped.
`
`{Patent document ‘iEJP 2000-348299A
`
`{Bisctosure of invention}
`
`{Prooiem to he soived by the invention}
`
`{0005}
`
`However, in the technique described in Patent Document “i, a GPS system and a vehicie
`
`speed sensor are necessary for each vehicie to acquire a driving situation of the vehicie.
`
`Further, since each vehicie regutariy transmits these information,
`
`the amount of
`
`communication increases.
`
`in particuiar, when the traffic iam occurs, the amount of
`
`communication becomes extremeiy tarde, and the interierence of radio waves occurs.
`
`resuiting in ditticnity in communication.
`
`{0006}
`
`it is an ooiect of the present invention to provide a wireiess communication techno-iogy
`
`capahie of detecting an arrivai direction of a vehicie by a simpie method.
`
`

`

`{Means tor sowing the prociern}
`
`{009?}
`
`The present invention is characterized in that, by using a piuraiity of receiving antennas.
`
`an azimirtn and a vehicie of a venicie are estimated based on a phase ditterence or a
`
`frequency deviation of a known signai transmitted from an in—venicie terminai.
`
`{0508}
`
`A radio communication device according to the present invention tor performing radio
`
`communication with an in-vehicie tenninai, wherein a piuraiity of reception antennas for
`
`receiving a known signai transmitted 1irorn the in-vet‘iicie terrninai ; and position estimation
`
`means for estimating an azimuth of the in-venicie tem’iinai based on a phase difference
`
`of the known signai received by the piuraiity of reception antennas ; A traveiing direction
`
`estimating means tor estimating whether the on—venicie terminai is approaching or away
`
`from the venicie based on the frequency deviation of the known signai received at the
`
`pturatity of receiving antennas ; A determination means for determining whether or not
`
`to periorm wireiess communication with the in-vehicie tenninai based on the estimation
`
`resutt by the position estimation means and the travei direction estimation means.
`
`{GU-09}
`
`Since the azimuth and the direction at the vehicie are estimated based on the phase
`
`difference and the frequency deviation of the known signais received at the p-iuraiity of
`
`reception antennas, it is not necessary to provide equipment such as a GPS device or a
`
`sensor on the venicie side. Further. since a known signai transmitted from the in—vehicie
`
`terminai is sufficient for a short signai, it is possioie to reduce the amount of intonnation
`
`to be transmitted and to reduce the power consirmption and power consumption.
`
`{Sm iii}
`
`in the wireiess communication apparatus according to the present
`
`invention,
`
`the
`
`reception antenna is a directionai antenna, and each of the reception antennas has
`
`directivity in a ditierent direction.
`
`{firm i}
`
`Further,
`
`in the wireiess communication apparatus according to the present invention
`
`attnough the reception antenna itseit has no directivity, a shieiding means for shieiding
`
`the radio wave is provided, and the reception antenna may be configured such that the
`
`reception antenna is shieided from the radio wave from the predetermined direction py
`
`the snieiding means whereby each of the reception antennas has directivity toward
`
`different directions. More specificatiy: it is possihie to adopt a configuration in wt‘iicn the
`
`shieiding means is a po-iygonai coiumn or a cyiindricai radio wave absorper, and a
`
`

`

`pidraiity of receiving antennas are arranged ciose to the radio wave ahsoroer so that the
`
`radio wave from the predetermined direction is shieided.
`
`{mi 2}
`
`As described shove, since the reception antenna has directivity so as to receive the radio
`
`wave trom the predetermined direction it is possihie to estimate the rough direction of
`
`the vehicie. Then, it is possihie to estimate a more detaiied azimuth based on the phase
`
`difference of the received signais at the pinraiity of reception antennas.
`
`{mi 3}
`
`it is preterahie that the wireiess communication apparatus of the present invention is
`
`arranged at an intersection, and that the pitiraiity of reception antennas have directivity
`
`with respect to the road direction, and that the determination means determines that the
`
`vehicte is in wireiess communication with the in—venicte terminai when the in—vehicie
`
`terminai approaches the corn apparatus from the predetermined road direction.
`
`{SSH}
`
`According to this configuration,
`
`it
`
`is possihie to appropriateiy estimate the traveiing
`
`direction of the vehicie at an intersection where the vehicie traveis in various directions
`
`and transmit the information oniy to the required vehicie.
`
`{001d}
`
`in addition, the present invention can he understood as a wireiess communication
`
`apparatus having at ieast a part of the above means. Further, the present invention may
`
`he understood as an inter—vehicie communication system comprising the above-
`
`mentioned wireiess communication device {roadside device} and the aforementioned in-
`
`vehicte terminat. Further.
`
`the present
`
`invention may he regarded as a wireiess
`
`communication method incioding at teast a part of the above processing or a program
`
`for reaiizing such a method. Each of the above means and processes can be combined
`
`as much as possioie to constitute the present invention.
`
`{0-016}
`
`For exampie, a road-to—vehicie communication system according to an embodiment oi
`
`the present invention is a road-to—vehicie commnnication system that performs wireiess
`
`communication between a roadside unit and an in—vehicie terminai, wherein the in-
`
`vehicie terminat inciudes a transmission unit that transmits a known signai, and the
`
`roadside nnit inciodes a transmission unit that transmits a known signai. A position
`
`estimating means for estimating an azimuth of the on-vehicte terminai based on a phase
`
`difference of the known signat received at the pioraiity of receiving antennas ;A traveiing
`
`direction estimating means tor estimating whether the on—vehicie tenninai is approaching
`
`or away from the roadside machine based on a trednency deviation of the known signai
`
`

`

`received at the ninraiity of receiving antennas ; A determination means tor determining
`
`whether or not to oertorm wireiess communication with the in—vehicie terminai based on
`
`the estimation resuit by the oosition estimation means and the travei direction estimation
`means.
`
`{Effect of the invention}
`
`{001?}
`
`According to the present invention. it is oossihie to detect an arrivai direction of a vehicie
`
`in a simoie manner.
`
`{Best mode for carrying out the invention}
`
`{0m 8}
`
`Hereinafter, preferred embodiments of the oresent invention Witt he described in detait
`
`with reference to the accompanying drawings.
`
`{00? 9}
`
`<System configuration?»
`
`Fit}. 1 is a diagram iiinstrating a system overview of the road-to—vehicte communication
`
`system according to the present embodiment. A roadside device ‘i {corresponding to a
`
`wireiess communication device in the present invention} set at an intersection provides
`
`information to a vehicie approaching the device from a predetermined road direction. in
`
`this embodiment, a oredetermined road direction is a iett side in HQ. ”t, and a service
`
`providing area 3 is a range as shown in the drawing.
`
`it is.
`
`{0020}
`
`For exempts. wt‘ien the information provided by the road—side machine t is information
`
`of a traffic tight in the right direction in the figure, a vehicte that requires this information
`
`is a vehicie that enters the intersection from the iett side in the drawing. Therefore, the
`
`service providing area 3 has a range as shown in the drawing. Converseiy, whether or
`
`not a vehicie is present in the service providing area 3 can he determined based on
`
`whether or not the vehicie is encroaching the roadside device t from the ieit in the
`
`drawing. Then, the read-side machine 1 performs wireiess communication with such a
`
`vehicte.
`
`in the exampie of HS.
`
`1.
`
`the roadside machine 'i performs wireiess
`
`communication with the vehieie A and does not nerton‘n wireiess communication with the
`
`vehicies B and C.
`
`{002i}
`
`<C~omoosition of a road-side machine>
`
`FiG. 2 is a diagram showing a configuration oi an antenna portion of the roadside
`
`

`

`apparatus 1. The roadside machine i has 4 antennas ANT t to ANT 4. The it antennas
`
`ANT “3 — ANT 4 are arranged ta term a square. Further, each at the antennas ANT 1 to
`
`ANT 4 is an omnidirectional antenna. However, each of the antennas ANT t to ANT it is
`
`disposed areund a cyiindricai radio wave ahsorher 3 that hiecks radin waves, and does
`
`not receive radio waves tram the direction at the radio; wave absorber 3‘. Thus, each is
`
`directed te a ditterent directien.
`
`{0022}
`
`As shown in HS. ii the road-side machine “3 is provided at an intersection {cross read}.
`
`The directiizity at each at the antennas ANT ‘i te ANT 4, is defined by the radie wave
`
`absorber 3 se as to strengty receive tactic waves train the respective read directiens. in
`
`other words, as a resutt ct shieiding the radie wave tram the predetermined directien by
`
`the radio wave ahscrher 3, each at the antennas ANT i te ANT 4 has a directivity with
`
`respect to the read direction”
`
`{8823}
`
`First. 3 is a diagram showing a tnnctienai configuration at the read-side machine i. The
`
`roadside machine 'i
`
`inctudes antennas ANT ‘i te ANT It, a synthesizer ii an arrivai
`
`directian estimatieh unit 12, a frequency detection unit t3, a, cemmunicatien centrei unit
`
`’34, and a ccmmnnicatien data precessihg unit i5.
`
`{8824}
`
`The synthesizer it caicuiates a comniex weight {weighting tacter} tar centreiiing the
`
`arnpiitude and phase of the received signai at the ninraiity at antennas ANT i te ANT 4,
`
`and synthesizes the signai adjusted by this weight. For caicuieti-en of the weights, tar
`
`exampte, a unique meduiatien Signet {khcwn signs!) may he used, er a wavetenn
`
`inserted into the transmissien signai periodicaity may he used, such as a guard intervai.
`
`{8825}
`
`The arrivai directien estimating unit t2 estimates the position at the vehieie based en the
`
`received signai strength or phase difference at” the unique meduiatien sighai tram the
`
`vehicte {in-vehicie terminai} received at each: antenna. Betaiis at” the vehicie nesitien
`
`estimatinn processing nerfcnned by the arrive! direction estimatien unit t2 Witt he
`
`described tater.
`
`{8828}
`
`A frequency detection unit
`
`ӣ3 caicuiates a trecinency shift antennt at an intrinsic
`
`rnedutatian signai received at each antenna. On the basis of this frequency shitt ameunt.
`
`the ccn‘rrnuhicatien centrei unit M can estimate whether the vehieie appreaches er
`
`metres away tram the vehicie, er farther estimates the mating speed at the vehicie.
`
`Detaiis of the process at detecting the frequency shitt ant-cunt performed by the
`
`

`

`frequency detection unit ӣ3 Witt he described tater.
`
`{002?}
`
`Communication controi unit “34 performs co-ntroi reiated to communication of roadside
`
`unit ”i
`
`in generai. and in particoiar, based on the position and the direction at movement
`
`of the vehicie estimated from directio-n-ot—arrivai estimation unit 12 and frequency
`
`detection unit 13 ;
`
`it is determined whether or not to perform wireiess communication. The communication
`
`data processing unit t5 processes the received data.
`
`{0028}
`
`in addition, in HS. 3, eniy the tonetionai unit reiated to reception of the roadside device
`
`“3 has been described, but the roadside device “3 aiso has a function reiated to
`
`transmission. However, the wireiess transmission function of the roadside device 1 may
`
`he impiernented in concrete manner. For exampie, there may he oniy one transmit
`
`antenna, and a pinraiity of transmit antennas.
`
`it may be configured to transmit radio waves oniy in the vehicie direction using an
`
`adaptive array technique.
`
`{0020}
`
`<Arrivai—directi-ons estimation processing?»
`
`An arrivai direction estimation part 12 estimates the position of the vehicie en the basis
`
`at the unique medntation signai transmitted from each vehicie. Upon receiving a beacon
`
`periodicaiiy transmitted from the roadside unit
`
`“i, each vehicie transmits a unique
`
`medntatiori signai tea. a packet preamhie) identifying the type of its oven terrriinat.
`
`{0030}
`
`i-iereinatter, the vehicie position estimation processing performed by the arri‘vai direction
`
`estimation unit 12 wiii he described with reference to FiGS, 4 and 5. Here, an exampie
`
`wiii be described in which the position of the vehicie A is estimated based on the unique
`
`moduiation signai received from the vehicie A in Fits. ’i.
`
`{003i}
`
`in the unique moduiation signai transmitted from the vehicie A. the reception strength of
`
`the antenna ANT ‘i is highest among the 4 antennas of the roadside device ‘i.’i'heretore,
`
`it can he roughiy determined that the vehicie A is iocated on the iett side of the road-side
`
`machine “3. The arrivai direction estimating unit “32 estimates a more detaiied azimuth of
`
`the vehicie A based on the phase difference of the received signat at each of the
`
`receiving antennas. Here, as shown in HS. ”L4. an angie 8 a irom the direction aiong
`
`the road on the iett side in the drawing is estimated.
`
`

`

`{0532}
`
`The arrivai direction estirnaticn unit t2 detects the phase difference between the
`
`received signais in the ANT 2 and the ANT 3‘ based on the antenna ANT 1' having the
`
`iargest received newer. The angie d strewn in HS. 4 can be catcuiated item the phase
`
`difference between the received signais of the antenna ANT ‘i and the antenna ANT 2.
`
`in addition. the angie - it shcwn in FiG. it can he caicuiated fruit; the phase difference
`
`between the received signats of the antenna ANT “i and the antenna ANT 3. in the case
`
`shown in HQ. 1,4, the phase difference of the antenna ANT ‘t is as shown in RS. 5.
`
`{0033}
`
`i-iere. since a = nr‘ 4 8 a and — fl = tr ; 4 - e a. it is feund that e a = {d n} f 2 is attained.
`
`That is, the azimuth of the vehicie can be estimated based an the phase difference at
`
`the unique meduiated signat (trnewn signai} received at each receiving antenna.
`
`{8834}
`
`<The amount detecticn processing of frequency deviaticn>
`
`Next, a precess at detecting a frequency shift arncunt at an intrinsic meduiated signat
`
`transmitted by the vehicie, which is perfermed by the frequency detection unit t3, Witt he
`
`described. The frequency of the unique rncduiaticn signai transmitted by each vehicie is
`
`fixed, but is affected by Bonnier shift er the tike because the vehicie is moving. Then, the
`
`frequency at the received signai received in the roadside device 1 shifts. The frequency
`
`detection unit "t3 detects this frequency shift amount.
`
`{0035}
`
`FiG. 6 shows a detaiied functionai bidet: cf the frequency detecticn unit t3. The
`
`frequency detection unit 13 inctndevs a quadrature demeduiatcr 13d, a detection circuit
`
`“i32, and a phase difference caisuiatcr t33.
`
`{8836}
`
`The quadrature dentedutator t3t duadrature—demedniates a received signai at an
`
`antenna having the iargest recentidn intensity amend the piuraiity of antennas ANT ‘t to
`
`ANT 4. and outputs an crthogonat demeduiated Signet divided into an t signai {in—phase
`
`ccmecnent) and a Q signai {quadrature compenent}. The detection circuit "Z32 detects
`
`{demodutates} the received signai from the t signai and the Q signat.
`
`{8837}
`
`The phase difference catcuiatcr "t 33 caisuiates the ante-Lint cf deviation of the frequency
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`of
`
`the derncdiiiated received signai
`
`from the frequency of
`
`the transmitted
`
`eigenrncduiated signai. First,
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`it is assumed that the intrinsic rncduiaticn signat V is
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`excressed as foitews.
`
`{8838}
`
`

`

`{Mathe-mettcei tomuie “3}
`
`Here, fc is the earrter frequency, ahd e c is the inittet phase.
`
`{0039}
`
`Then, it is assumed that the receptteh Signet Vt' ctemeduieted by the detection circuit £32
`
`is expressett as tettows,
`
`{0040}
`
`{Methematteat termuia 2}
`
`Here, A 8 is a ftequehcy shtfi amount.
`
`{GU-4’3}
`
`Note that the tree tsehe’y‘ shift ametmt A e is determihed by the Beppter shift and the phase
`
`change due to the muttipeth.
`
`{0042}
`
`{Methametteei fermute 3}
`
`Here: 2 T! tdt represents a Doppter shift anthem, and 8 m represents a phase change
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`amount due t0 e muittpath.
`
`{GU-43}
`
`th an antenna with the strengest receptieh intensity. the ameuht et {leppiet shift
`
`is
`
`demthaht in the frequency shift emeuhtm Accordihgty, £8. 9 represented by the feitowthg
`
`equation tepresents the Deppter shift amount.
`
`{0044}
`
`{Methematteat termuia 4}
`
`

`

`{0045}
`
`Benending on whether the frequency shitt amount thns determined is positive or negative,
`
`it is possihie to estimate whether the vehicie is approaching or moving away from the
`
`road side machine "i.
`
`{0-046}
`
`FiG, I?“ shows a frequency shitt at the received signai from the vehicie A received try each
`
`of the antennas ANT 1 to ANT 4 in the situation of Fits. t. i-iere: since the reception
`
`intensity at the antenna ANT 1 is strongest, the frequency shift amount of the reception
`
`signai of the antenna ANT ”i
`
`is obtained. As shown in HS. 7 a, since the Bonnier shift
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`amount id = tra ‘i - fc> 0,
`
`it can he determined that the vehicie A is approaching the
`
`roadside device ‘im
`
`{004?}
`
`in addition, the traveiing direction of the vehicie may be estimated taking into account
`
`not oniy’ the reception signai of the antenna having the highest reception intensity but
`
`aiso the frequency shitt of the other antenna.
`
`{0-048}
`
`<Cornrnnnication chiect vehicies decision orccessing>
`
`As described above it is possihie to obtain the direction in which the vehicie is iocated
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`and the direction of trave-i {whether the vehicie is anoroaching or moving away from each
`
`other} by the arrivai direction estimating unit t2 and the frequency detecting unit 13.
`
`Communication
`
`Based on these resnits, the control unit 14 pertonns a process of determining a vehicie
`
`to be communicated. Hereinafter: this processing wiii he descrihed.
`
`{0040}
`
`As shown in HS. “i, when 3 vehicies of vehicies A to C exist, the processing resuits of
`
`the arrivai direction estimation unit t2 and the 1Frequency detection unit is obtained from
`
`the reception resuits at the unique moduiation signais transmitted from these vehicies
`
`are as shown in HQ at
`
`{005-03
`
`With respect to the vehicie A, it is estimated that the vehicie A is present in an azimuth
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`of 0 to rr r“ 2 from the phase difference of the received signai, and it is estimated that the
`
`vehicie A is approaching the road-side machine “i
`
`trorn the Bonnier shift. About the
`
`vehicies 8, existing in the direction at 0 — pit? from the phase contrast of a reception
`
`signai is presented and keeping away from the road—side machine ‘i is presumed from
`
`a Bonnier shift. For the vehicie C,
`
`it is estimated that the vehioie C is present in an
`
`

`

`azimuth of tr f 2 to n from the phase difference of the received signai, and it is estimated
`
`that the vehicte C is approaching the road—side machine i from the Doppier shift.
`
`{0053}
`
`Since the service providing area 3 of the road-side machine ”i
`
`is as shown in HQ. i. it
`
`can be determined that the vehicie approaching the road-side machine ‘i from the teit in
`
`the drawing is a vehicte to he oomrnunicated. Then‘ in accordance with the fiowchart
`
`shown in HS. 8, the communication controi unit 14 determines whether or not each
`
`vehicie is to he communicated.
`
`{0052}
`
`in other words. the communication controi unit it sets a vehicie whose arrivai direction
`
`is within a range of {I} to rr 3 2 and whose Doppier shift is positive {approaching the road
`
`side machine i} as an ohiect of communication. Here, the vehicie A is iocatect in a range
`
`of i} to n i 2 {8 t - YES}, and is a communication target because the Doppier shift is
`
`positive {8 2 - YES}. On the other hand, aithoogh the vehioie 8 is iocated in the range of
`
`0 to rr .5 2 {S ‘i - YES}, since the Boppier shift is negative {8 2 - N0}, the vehicie B is not
`
`a communication target. Further, since the vehicie C is not iocated within the range of C}
`
`to n g 2 {S ’i - NO}, the vehioie C is not a communication target.
`
`{0033}
`
`«at working effect and effect of an emhodiment>
`
`in this way. the road—side machine “i can estimate the position and direction of the vehicie‘
`
`and can easii’y‘ determine the vehioie to he communicated.
`
`{0054}
`
`Here, the vehicie side mereiy transmits a unique modniation signai {preamhie}, and it is
`
`not necessary to provide a GPS device, a sensor. or the titre and it is possihie to easiiy
`
`and inexpensiveiy configure the vehicie. Further. since the vehic-te side transmits a short
`
`inherent modoiation signai rather than transmitting a packet whose payioad is the
`
`position information,
`
`its own it}, and the titre,
`
`it is possihie to reduce the amount of
`
`communication and reduce the use hand and power consumption.
`
`{ores}
`
`{ Modification}
`
`in addition to the configuration shown in Fit}. 2, various configurations can he emit-toyed
`
`tor the antenna of the road-side machine ”i
`
`in consideration at a road a shape oi the
`
`service providing area, and the titre. Some exampies are shown in HQ. it}. For examoie.
`
`as shown in HS. 30 a. the shape of the radio wave absorber 3 may he a attadrangniar
`
`prism instead of a cyiindricai shape. As a resuit, simiiar ettects can he obtained.
`
`in
`
`addition. the numher of antennas need not he 4, and may he 3 or more and 5 or more.
`
`

`

`in case of 3 antennas. it is nreterahie to use a trianguiar have absorber as shown in HG.
`
`it} h. in addition, in case of 5 antennas, as shown in Fit}. it} c, it is preterahie to use a 5
`
`orism radio wave absorber. Further, the shape of the radio wave absorber is not iirnited
`
`to a cyiindricai shape or a poiygonai coiumn shade, and as shown in HS. ti) dc a piste-
`
`shaged radio wave absorber may he nrovided behind each antenna. Further. the
`
`antenna itseit may have directivity.
`
`{0055}
`
`in the above described embodiment, the service providing area 3 is ciose to one of the
`
`intersections.
`
`However, the present invention is not iirnited thereto. For exampie, in RE. i a vehieie
`
`{approaching the roadside device ‘i from the iett direction and the right direction may he
`
`a communication target.
`
`it is oossihie to anoronriateiy set nhether or not to perform
`
`communication on the basis of any other vehicie in accordance with information provided
`
`by the roadside device “i.
`
`{005?}
`
`in addition, in the above described embodiment, the road side machine ”i
`
`is orovided
`
`with aii road directions at intersections.
`
`Each of the antennas has an antenna having directivity. However, it is not necessary to
`
`have an antenna for some directions. For examoie, the antenna ANT 4 may be omitted
`
`in the shove description.
`
`{0-058}
`
`in addition, in the description of the embodiment, the wireiess communication device
`
`according to the present invention is contigured as the roadside device t. in other words
`
`in the inter-vehicie communication, it is oossihie to determine the presence direction and
`
`the travei direction of the oncoming vehicie based on the unique moduiation signai as
`
`described above.
`
`{Brief Description of the Drawings}
`
`{0059}
`
`{Fig tiFtG. “i is a diagram showing an overview of an entire system of a road-to-vehicie
`
`communication system according to the present embodiment ;.
`
`{Fig EiFiG. 4 is a diagram showing a structure of an antenna inciuded in a roadside
`
`device ;.
`
`{Fig 33Fit‘3. 3 is a diagram shoeing a functionai configuration of a roadside machine ;.
`
`{Fig did is the tigure showing the phase contrast in the arrivai directions and each
`
`antenna of a reception signai.
`
`

`

`{Fig 53Fii3. 4 is a diagram iiiustraiing a phase difference of received signais received £33;
`
`each antenna ;.
`
`{Fig 63FiG. 3 is a detaiied iunetionai bieek diagram of a frequency detection unit inciuded
`
`in a roadside apparatus ;.
`
`{Fig ?{FiG. 4 shows Bonnier shift amount of a received Signet received at each; antenna ;.
`
`{Fig SiFiG. 4 is a diagram showing detection resuits of an arrivai direction and a Doppier
`
`sniii amount at a venicie ;.
`
`{Fig 9}FiG. 4 is a flowchart showing a flow of processing for determining whether or not
`
`a venicie is to be communicated :.
`
`{Fig "ifijFiG. 4 is a diagram showing another exampie of the stnietnre of an antenna
`
`incinded in a roadside device ;.
`
`{Expianation of Setters or numerais}
`
`{SSE-fl}
`
`ANHANTEANTSANM antenna
`
`3
`
`Road-Side Machine
`
`“ii synthesize-r
`
`“32 arrival direction estimation unit
`
`’33 frequency detection unit
`
`13’: quadrature demoduiater
`
`332 Uetector Circuit
`
`333
`
`“34
`
`F‘nase Contrast Comeiiter
`
`Communication Contrei Part
`
`’35 communicaiien data processing unit
`
`

`

`.3? 2388*23391? A 2038. 33.2
`
`113,1 333-333(39)
`
`(12.; {3 Ba 43 3F ’1} $0!)
`
`111333333333
`ififlfiflbflflfl?
`(Patna-2330173)
`(431 33 El 33203133231303.1113)
`
`F 1
`
`{51'} 113111.
`60 I s 33
`(2:13.93)
`so 3 s 33
`3.10413
`3523
`(313.93)
`H043 was
`808G 139
`33309
`6086 139
`H0 I (3
`1,332
`H010 352 mm)
`H910 21/3 may;
`HO 1 Q 21523
`3333: 333: 3333.33 3 UL
`I313 33
`
`
`H
`F
`
`3—32— F (33%}
`SH I 80
`5.131
`53043
`5 ms 7
`
`(21) ifififi‘g
`
`(22) Efififi
`
`13533200?— ?6T31 {PZUOT TERM)
`E—EE13$3B 2313 (20013 .23)
`
`
`
`
`{N} WEEK SDEUSMSU
`$3396.33 F a; l ’l‘fififit >25?“
`33333333T363203
`{33A33333 331833 33333333tfiufi3313w33
`3333335133321133