WO2021117299A1 - Mobile communication system, on-board mobile station, wireless control station, control method for transmission beam, and control method for reception beam - Google Patents

Abstract

This mobile communication system comprises: a wireless control station that transmits information necessary for communication connection; an on-board mobile station that waits for the information while changing the orientation of the reception beam. The on-board mobile station is provided with: a reception antenna for forming the reception beam; and a reception antenna control unit that changes, in accordance with the position of the on-board mobile station, the variable range of the orientation of the reception beam.

Description

Mobile communication system, in-vehicle mobile station, wireless control station, transmission beam control method, and reception beam control method

The present disclosure relates to a mobile communication system, an in-vehicle mobile station, a wireless control station, a transmission beam control method, and a reception beam control method.
This application claims priority based on Japanese Application No. 2019-222964 filed on December 10, 2019, and incorporates all the contents described in the Japanese application.

In the 5th generation mobile communication system, since wireless communication is performed using millimeter waves or quasi-millimeter waves, propagation loss is large. Therefore, the radio control station or mobile station in the system performs beamforming in order to compensate for the attenuation of radio waves. Radio control stations and mobile stations can improve gain by directing the beam in a specific direction by beamforming.

Since the wireless control station (mobile station) performs wireless communication with the directivity direction of the beam directed to the mobile station (radio control station), it is necessary to specify the directivity direction of the beam directed to the mobile station (radio control station).
Therefore, the wireless control station performs beam sweeping at a stage before starting wireless communication with the mobile station. Beam sweeping is a process for searching for a mobile station capable of communication connection by changing the directivity direction of the beam and identifying an appropriate directivity direction for the mobile station.

In beam sweeping, the radio control station sequentially transmits broadcast information by a plurality of transmission beams having different directivity directions. When the mobile station receives this broadcast information, it transmits the minimum information (preamble), the identification information of the broadcast information, and the like to the wireless control station.
The radio control station recognizes the existence of the mobile station by receiving the information transmitted from the mobile station, identifies the transmission beam of the broadcast information from the identification information of the broadcast information, and indicates an appropriate direction to the mobile station. Can be specified (see, for example, Patent Document 1).
After that, a random access process is performed between the wireless control station and the mobile station, and then a communication connection is made and wireless communication is started.

International Publication No. 2018/134995

The mobile communication system according to the embodiment is a mobile communication system including a wireless control station that transmits information necessary for communication connection and an in-vehicle mobile station that waits for the information while changing the directivity direction of a reception beam. The in-vehicle mobile station includes a receiving antenna that forms the receiving beam, and a receiving antenna control unit that changes a variable range of the directivity direction of the receiving beam according to the position of the in-vehicle mobile station.

Further, the mobile communication system according to another embodiment includes a wireless control station that transmits information necessary for communication connection between the vehicle-mounted mobile station and the vehicle-mounted mobile station while changing the direction of the transmission beam. The wireless control station is a mobile communication system including the above, and the radio control station has the transmission beam according to the light color of the transmission antenna forming the transmission beam and the traffic signal installed on the road on which the vehicle-mounted mobile station moves. It is provided with a transmitting antenna control unit that changes the variable range of the direction of the above.

Further, the in-vehicle mobile station according to another embodiment is an in-vehicle mobile station that waits for information necessary for communication connection from a wireless control station while changing the directivity direction of the reception beam, and is a reception that forms the reception beam. It includes an antenna and a receiving antenna control unit that changes a variable range of the directivity direction of the receiving beam according to the position of the vehicle-mounted mobile station.

The wireless control station according to another embodiment is a wireless control station that transmits information necessary for communication connection with an in-vehicle mobile station while changing the directivity direction of the transmission beam, and forms the transmission beam. It includes a transmitting antenna and a transmitting antenna control unit that changes a variable range of the directivity direction of the transmitting beam according to the light color of a traffic signal installed on the road on which the vehicle-mounted mobile station moves.

Another embodiment of the reception beam control method is a reception beam control method performed by an in-vehicle mobile station that waits for information necessary for communication connection from a wireless control station, and the reception beam is controlled while changing the direction of direction. The step of forming and the step of changing the variable range of the directing direction of the received beam according to the position of the in-vehicle mobile station are included.

Further, the transmission beam control method according to another embodiment is a transmission beam control method performed by a wireless control station that transmits information necessary for communication connection with an in-vehicle mobile station by the transmission beam, and is directed. A step of forming the transmission beam while changing the direction, a step of changing the variable range of the direction of the transmission beam according to the color of a traffic signal installed on the road on which the vehicle-mounted mobile station moves, and a step of changing the variable range of the direction of the transmission beam. including.

The present disclosure can be realized as a program for causing a computer to execute a step which is a characteristic process described above.

FIG. 1 is a plan view showing a part of the area where the mobile communication system according to the embodiment is installed. FIG. 2 is a block diagram showing an example of a connection mode between each device installed on the road and the device installed in the station building of the wireless control station. FIG. 3 is a perspective view showing an example of the remote unit. FIG. 4 is a block diagram showing an example of the configuration of the remote unit. FIG. 5A is a perspective view showing an example of an in-vehicle mobile station. FIG. 5B is a block diagram showing an example of the configuration of an in-vehicle mobile station. FIG. 6 is a block diagram showing an example of the configuration of the first antenna module. FIG. 7 is a sequence diagram showing a process performed when the wireless control station and the mobile station communicate with each other. FIG. 8 is a diagram showing a directivity direction of a transmission / reception beam that can be formed by the remote unit of the present embodiment. FIG. 9 is a diagram showing an example of a downlink radio frame by a radio control station. FIG. 10 is a diagram showing a directivity direction of a transmission / reception beam that can be formed by an in-vehicle mobile station of a vehicle. FIG. 11 is a flowchart showing control of a variable range of the directivity direction of the transmission beam by the remote unit performed by the antenna control device. FIG. 12 is a diagram showing an example of a downlink radio frame by a radio control station in the restricted mode. FIG. 13 is a diagram showing an example of a variable range of a beam set for each remote unit at an intersection. FIG. 14 is a flowchart showing control of a variable range of the directivity direction of the received beam performed by the in-vehicle mobile station. FIG. 15 is a flowchart showing an example of processing in the restricted mode. FIG. 16 is a diagram for explaining a variable range of the directivity of the reception beam of the vehicle-mounted mobile station traveling on the road R. FIG. 17 is a diagram showing a state in which a truck is traveling in front of an in-vehicle mobile station.

[Issues to be solved by this disclosure]
Here, since the wireless control station searches the entire range in the azimuth direction around its own station by beam sweeping, it may also search for an area where the mobile station does not exist, and the wireless control station may search for the presence of the mobile station. It may take a relatively long time to recognize.

Further, since the mobile station also performs wireless communication with the directivity direction of the beam directed to the wireless control station, it is necessary to specify the directivity direction of the beam directed to the wireless control station. Therefore, the mobile station also attempts to receive the broadcast information transmitted from the wireless control station while changing the directivity direction of the reception beam before starting wireless communication with the wireless control station. As a result, the mobile station searches for the radio control station (notification information from) and identifies the directivity direction of the beam toward the radio control station.
For this reason, even in a mobile station, when searching for a wireless control station, a search in a direction in which the wireless control station does not exist may be performed, so that it takes a relatively long time for the mobile station to recognize the existence of the wireless control station. May be required.

As described above, when it takes a relatively long time for the beam sweeping by the wireless control station and the search for the wireless control station by the mobile station, for example, the mobile station enters the area where the wireless control station can communicate with the wireless control station and then wirelessly operates. There may be a delay in the time until communication starts.

This disclosure was made in view of such circumstances, and an object of the present disclosure is to provide a technology capable of promptly starting wireless communication.

[Effect of the present disclosure]
According to the present disclosure, wireless communication can be started promptly.

First, the contents of the embodiments will be listed and described.
[Outline of Embodiment]
(1) The mobile communication system according to the embodiment is a mobile communication including a wireless control station that transmits information necessary for communication connection and an in-vehicle mobile station that waits for the information while changing the directivity direction of a reception beam. In the system, the in-vehicle mobile station includes a receiving antenna forming the receiving beam and a receiving antenna control unit that changes a variable range of the directivity of the receiving beam according to the position of the in-vehicle mobile station. Be prepared.

According to the mobile communication system having the above configuration, when searching for a wireless control station capable of communication connection by waiting for information necessary for communication connection, the in-vehicle mobile station directs the reception beam according to the position of the in-vehicle mobile station. Change the variable range of direction. Therefore, the in-vehicle mobile station is variable when there is an area around the own station where it is clear that the wireless control station does not exist, or when wireless communication is performed with the wireless control station located in a certain direction. It can be changed to narrow the range. As a result, the time required to search for the wireless control station can be shortened, and wireless communication can be started promptly.

(2) In the mobile communication system, when the position of the vehicle-mounted mobile station is outside the predetermined area, the receiving antenna control unit sets the variable range as the first reception range, and the position of the vehicle-mounted mobile station is the predetermined area. If it is within, the variable range may be a second reception range narrower than the first reception range.
In this case, since the in-vehicle mobile station sets the variable range to the second reception range narrower than the first reception range within the predetermined area, the in-vehicle mobile station searches for the wireless control station within the predetermined area rather than outside the predetermined area. The time required for this can be shortened as needed, and wireless communication can be started promptly.

(3) Further, in the mobile communication system, the predetermined area may be an area set on the upstream side of an intersection located in front of the vehicle-mounted mobile station in the traveling direction.
In this case, the in-vehicle mobile station can search for the wireless control station by narrowing the variable range in the traveling direction if the vehicle enters the predetermined area. If the wireless control station is installed at the intersection, the in-vehicle mobile station can quickly search for the wireless control station and can promptly start wireless communication with the wireless control station installed at the intersection.

(4) Further, in the mobile communication system, the wireless control station includes a remote unit installed on the road and capable of communicating with the vehicle-mounted mobile station, and the predetermined area is located in front of the vehicle-mounted mobile station in the traveling direction. It may be an area set on the upstream side of the remote unit located.
In this case, the in-vehicle mobile station can search for the wireless control station by narrowing the variable range in the traveling direction if the vehicle enters the predetermined area. As a result, the in-vehicle mobile station can quickly search for the wireless control station and can promptly start wireless communication with the wireless control station.

(5) In the mobile communication system, the second reception range may be a range in which the directivity direction of the reception beam is limited to the beam directed in the traveling direction of the vehicle-mounted mobile station.
In this case, by setting the variable range as the second reception range, the in-vehicle mobile station can search for the wireless control station by narrowing down the traveling direction.

(6) Further, in the mobile communication system, when the information cannot be received while the vehicle-mounted mobile station travels by a predetermined mileage after the vehicle-mounted mobile station enters the predetermined area, the receiving antenna control is performed. The unit may change the variable range so that the directivity direction is limited to the reception beam directed in the direction opposite to the traveling direction of the vehicle-mounted mobile station.
If the information cannot be received within the predetermined area, it is possible that an obstacle blocking the reception beam exists in front of the in-vehicle mobile station. Therefore, if the in-vehicle mobile station changes the variable range to a range facing in the opposite direction of the traveling direction and directs the received beam in the opposite direction of the traveling direction, the vehicle exits the predetermined area and exits the intersection or the wireless control station. After passing through, the radio control station at the rear position can be quickly searched.

(7) Further, in the mobile communication system, the receiving antenna control unit changes the variable range to the first receiving range when the vehicle-mounted mobile station moves out of the predetermined area and then travels by a predetermined distance. It may be configured as follows.
In this case, the search for the radio control station located behind the in-vehicle mobile station can be continued from the time of leaving the predetermined area to the time of traveling by a predetermined distance.

(8) In the mobile communication system, the radio control station transmits the information while changing the directivity direction of the transmission beam, and a light of a traffic signal installed on a road on which the in-vehicle mobile station moves. A transmission antenna control unit that changes a variable range of the directivity direction of the transmission beam according to the color may be provided.
In this case, the radio control station can change the variable range of the directivity of the transmission beam according to the movement mode of the vehicle-mounted mobile station that stops or moves depending on the light color of the traffic signal.
Therefore, for example, in order to preferentially search for an in-vehicle mobile station that is permitted to travel by a green light and moves on the road, the radio control station can be changed to narrow the variable range to the range corresponding to the road. .. As a result, the time required to search for an in-vehicle mobile station moving on the road can be shortened, and wireless communication can be started promptly.

(9) Further, the mobile communication system according to another embodiment is a wireless control that transmits information necessary for communication connection between the vehicle-mounted mobile station and the vehicle-mounted mobile station while changing the direction of the transmission beam. A mobile communication system including a station, wherein the wireless control station responds to the color of the transmitting antenna forming the transmitting beam and the light color of a traffic signal installed on the road on which the in-vehicle mobile station moves. A transmission antenna control unit that changes a variable range of the direction of the transmission beam is provided.

According to the mobile communication system having the above configuration, the wireless control station narrows the variable range of the directing direction of the transmission beam according to the movement mode of the in-vehicle mobile station that stops or moves depending on the light color of the traffic signal. Can be changed. As a result, when searching for an in-vehicle mobile station capable of communicating by transmitting information necessary for communication connection, the time required for the search can be shortened, and wireless communication can be started promptly. ..

(10) In the mobile communication system, the transmission antenna control unit can change the variable range to either a first transmission range or a second transmission range narrower than the first transmission range.
In this case, if the variable range is changed to the second transmission range, the time required to search for the in-vehicle mobile station can be shortened as compared with the case of the first transmission range, and wireless communication can be started promptly. it can.

(11) In the mobile communication system, the second transmission range is preferably a range in which the directivity direction of the transmission beam is limited to the beam directed in the extending direction of the road.
(12) Further, in the mobile communication system,
The transmitting antenna control unit may change the variable range from the first transmitting range to the second transmitting range when the road is permitted to travel by switching the light color of the traffic signal. ..
In this case, the radio control station can increase the chances of searching for an in-vehicle mobile station on the road by limiting the range forming the transmission beam to the permitted road when the road is permitted to travel. .. As a result, it is possible to effectively search for an in-vehicle mobile station that is allowed to proceed and passes through the road in a short time.

(13) Further, the in-vehicle mobile station according to another embodiment is an in-vehicle mobile station that waits for information necessary for communication connection from a wireless control station while changing the directivity direction of the received beam, and receives the received beam. It includes a receiving antenna to be formed and a receiving antenna control unit that changes a variable range of the directivity direction of the receiving beam according to the position of the vehicle-mounted mobile station.

(14) Further, the wireless control station according to another embodiment is a wireless control station that transmits information necessary for communication connection with an in-vehicle mobile station while changing the directivity direction of the transmission beam. It includes a transmitting antenna that forms a transmitting beam, and a transmitting antenna control unit that changes a variable range of the directivity of the transmitting beam according to the light color of a traffic signal installed on the road on which the vehicle-mounted mobile station moves. ..

(15) Further, the reception beam control method according to another embodiment is a reception beam control method performed by an in-vehicle mobile station that waits for information necessary for communication connection from a wireless control station, and changes the direction of direction. It includes a step of forming a receiving beam while changing a variable range of a directing direction of the receiving beam according to the position of the vehicle-mounted mobile station.

(16) Further, the transmission beam control method according to another embodiment is a transmission beam control method performed by a wireless control station that transmits information necessary for communication connection with an in-vehicle mobile station, and is a directing direction. The step of forming a transmission beam while changing the transmission beam and the step of changing the variable range of the direction of the transmission beam according to the light color of the traffic signal installed on the road on which the vehicle-mounted mobile station moves are included. ..

[Details of Embodiment]
Hereinafter, preferred embodiments will be described with reference to the drawings.
In addition, at least a part of each embodiment described below may be arbitrarily combined.
[Overall configuration of mobile communication system]
FIG. 1 is a plan view showing a part of the area where the mobile communication system according to the embodiment is installed. In FIG. 1, the upper side of the paper is north and the lower side of the paper is south.
In FIG. 1, the mobile communication system includes a wireless control station 1 and a mobile station 4.

The wireless control station 1 includes a plurality of remote units 2. The remote unit 2 is also called a base station, a radio control station, a remote radio head, or the like.
The wireless control station 1 has a function of performing wireless communication with the mobile station 4 by the remote unit 2. The remote unit 2 performs wireless communication based on, for example, a 5th generation mobile communication system. The remote unit 2 has a function of performing beamforming on the transmission beam and the reception beam, and communicates with the directivity direction of the transmission / reception beam toward the communication destination.
A plurality of remote units 2 (four in the example) are installed at the intersection I on the road R. The remote unit 2 is installed, for example, corresponding to a plurality of traffic signals 6 installed in each direction of the intersection I.

The mobile station 4 includes a mobile terminal 4b such as a mobile phone, a smartphone, a tablet terminal, a laptop computer, etc. possessed by a pedestrian H or the like, in addition to the vehicle-mounted mobile station 4a mounted on the vehicle V.
The mobile station 4 performs wireless communication with the wireless control station 1 in accordance with the 5th generation mobile communication system. Therefore, the mobile station 4 also has a function of performing beamforming, and communicates with the directivity direction of the transmission / reception beam directed to the communication destination.
Further, the mobile station 4 may have a function of performing wireless communication conforming to the 4th generation mobile communication system. The area to which the wireless control station 1 can provide the service is included in the cell formed by the wireless control station by the 4th generation mobile communication system, and transmission / reception by both communication systems is possible.

The plurality of remote units 2 are connected to the line concentrator 10. The concentrator 10 has an interface function for connecting a plurality of remote units 2 and an aggregation device (described later) installed in a station building of a mobile communication system.
Further, a signal controller 12 for controlling a plurality of traffic signals 6 is also connected to the line concentrator 10. The line concentrator 10 also has an interface function for connecting the signal controller 12 and the central control device (described later) installed in the traffic control center of the Intelligent Transport Systems (ITS).
A roadside wireless communication device 14 by an ITS wireless system is connected to the signal controller 12. The roadside wireless communication device 14 can perform wireless communication with the vehicle-mounted communication device 16 by the ITS wireless system mounted on the vehicle V.

FIG. 2 is a block diagram showing an example of a connection mode between each device installed on the road R and the device installed in the station building of the wireless control station 1.
As shown in FIG. 2, the remote unit 2 is installed at a high place by a support column 7 together with a traffic signal 6. Further, the roadside wireless communication device 14 is also installed on the support column 7.
In the present embodiment, the remote unit 2 is installed on the road R by the support columns 7. Here, on the road R means a position on the road R where the remote unit 2 can form a transmission / reception beam along the direction in which the road R extends. Therefore, it does not have to be directly above the road R, and may be a position where the transmission / reception beam can be formed.

The wireless control station 1 includes an aggregation device 20 in addition to the remote unit 2.
As shown in FIG. 2, the aggregation device 20 is installed in the station building B located at a location away from the remote unit 2.
The aggregation device 20 is connected to the line concentrator device 18.
The line concentrator 18 is connected to the line concentrator 10 via an optical transmission line 11. The line concentrator 10 and the line concentrator 18 have a function of performing optical communication, and the remote unit 2 installed on the road R side and the aggregation device 20 installed in the station building B communicate with each other by optical communication. It has a function as an interface for connecting communicably. Therefore, the plurality of remote units 2 and the aggregation device 20 are connected to each other so as to be able to communicate with each other by the line concentrator 10 and the line concentrator 18.

The aggregation device 20 is, for example, a device also called a central unit, and is connected to the core network NW1 of the mobile communication system. The aggregation device 20 is composed of a computer including a CPU (Central Processing Unit) and a storage device such as a memory and a hard disk. The storage device included in the aggregation device 20 stores a computer program or the like for execution by the CPU. When the CPU reads and executes this computer program, each function of the aggregation device 20 is realized.
The aggregation device 20 realizes the function of the aggregation device 20 by reading the program recorded on a non-transient recording medium that can be read by a computer such as the storage device.

The aggregation device 20 functionally has a communication processing unit 20a. The communication processing unit 20a performs necessary processing on the digital baseband signals given from the plurality of remote units 2, and supplies the communication data obtained by the processing to the core network NW1. Further, the communication processing unit 20a performs necessary processing on the communication data given from the core network NW1 to generate a digital baseband signal, and gives the digital baseband signal to the plurality of remote units 2. The aggregation device 20 stores communication data and various information related to wireless communication in a predetermined wireless frame, and performs the above processing on various information stored in the wireless frame to generate a digital baseband signal.

Further, the communication processing unit 20a searches for a communication-connectable mobile station 4 existing around the remote unit 2 by transmitting notification information or the like which is information necessary for communication connection, and communicates with the detected mobile station. It has a function to perform processing for communication connection with.
Further, the communication processing unit 20a can specify the directivity direction of the transmission / reception beam in the wireless communication with the mobile station 4 for each predetermined unit such as data in the wireless frame, a block, or an area. The communication processing unit 20a provides the remote unit 2 with directivity information for designating the directivity direction of the transmission / reception beam for each predetermined unit.
Further, when the variable range information (described later) is given from the remote unit 2, the communication processing unit 20a determines the directing direction of the transmission beam for each predetermined unit within the range indicated by the variable range information, and determines the directing direction. Information is given to the remote unit 2.

Further, in the station building B, in addition to the aggregation device 20, an ITS communication device 22 is installed.
The ITS communication device 22 is connected to the line concentrator 18. The line concentrator 10 and the line concentrator 18 also have a function of connecting the signal controller 12 and the ITS communication device 22 installed in the station building B so as to be able to communicate with each other by optical communication. Therefore, the signal controller 12 and the ITS communication device 22 are communicably connected to each other by the line concentrator 10 and the line concentrator 18.

The ITS communication device 22 is communicably connected to the central control device 24 installed in the traffic control center via the network NW2 by an individual communication carrier or the like with the core network NW1. The ITS communication device 22 transmits the communication data given by the central control device 24 to the signal controller 12. Further, the ITS communication device 22 transmits the communication data given by the signal controller 12 to the central control device 24.

The central control device 24 generates signal control commands and traffic information regarding the timing of switching the light colors of the plurality of traffic signals 6, and transmits these information to the signal controller 12. When a signal control command is given, the signal controller 12 controls the light color according to the signal control command. Further, when the traffic information is given, the signal controller 12 gives the given traffic information to the roadside wireless communication device 14.
The roadside wireless communication device 14 transmits this traffic information to the vehicle-mounted communication device 16 on the road R. Further, when traffic information, probe information, or the like is given from the vehicle-mounted communication device 16, the roadside wireless communication device 14 gives the given information to the signal controller 12. The signal controller 12 gives information from the in-vehicle communication device 16 to the central control device 24 via the ITS communication device 22 and the network NW2.

The signal controller 12 is communicably connected to a plurality of remote units 2 via the line concentrator 10. The signal controller 12 has a function of giving light color information indicating the light color of each traffic signal 6 to a plurality of remote units 2.

[About the configuration of remote unit 2]
FIG. 3 is a perspective view showing an example of the remote unit 2.
The remote unit 2 includes a box-shaped housing 30 and a plurality of array antennas 32.
A plurality of (four in the example) array antennas 32 are arranged so as to surround the side surface of the housing 30.
The array antenna 32 includes a substrate 32a and a plurality of antenna elements 32b mounted on the substrate 32a, respectively. The antenna element 32b is, for example, a planar antenna such as a patch antenna.
Each array antenna 32 can perform beamforming by adjusting the phase of signals transmitted and received by a plurality of antenna elements 32b. Each array antenna 32 can form a transmission / reception beam in a range of an azimuth angle of about 90 degrees about the normal line of the substrate 32a. As a result, the remote unit 2 can form a transmission / reception beam directed in all directions of the remote unit 2.
The remote unit 2 has, for example, a plurality of transmission / reception systems, and forms a beam for each transmission / reception system. The remote unit 2 has a function of transmitting and receiving radio waves to and from the mobile station 4 while performing beamforming.

FIG. 4 is a block diagram showing an example of the configuration of the remote unit 2.
As shown in FIG. 4, the remote unit 2 includes four array antennas 32, a synthesis distributor 34, a transceiver 36, and an antenna control device 38.
The composite distributor 34, the transceiver 36, and the antenna control device 38 are housed inside the housing 30.
Each array antenna 32 is connected to the transceiver 36 via the composite distributor 34.

The transmitter / receiver 36 performs processing such as modulation, amplification, digital / analog conversion, and frequency conversion on the digital baseband signal given from the aggregation device 20 to generate a radio frequency signal (RF signal). The generated RF signal is given to the array antenna 32 via the synthesis distributor 34.
Further, the transceiver 36 performs processing such as amplification, frequency conversion, analog / digital conversion, and demodulation on the RF signal received by the array antenna 32 to generate a digital baseband signal. The generated digital baseband signal is given to the aggregation device 20.
The transceiver 36 processes a plurality of transmission / reception systems corresponding to the plurality of transmission / reception systems of the remote unit 2. Therefore, the transceiver 36 generates an RF signal for each of a plurality of systems, and generates a digital baseband signal for each of the plurality of systems.
The synthesis distributor 34 synthesizes the RF signals received by the plurality of antenna elements 32b for each receiving system and gives them to the transceiver 36, and transfers the RF signals given from the transceiver 36 to the plurality of antenna elements 32b for each transmitting system. Distribute.

The array antenna 32 feeds the received radio wave as an RF signal to the transceiver 36. Further, the array antenna 32 radiates the RF signal given from the transceiver 36 into space as a radio wave.
The array antenna 32 includes a plurality of antenna elements 32b and a phase adjuster 40.
The phase adjuster 40 adjusts the phases of a plurality of signals transmitted and received by the plurality of antenna elements 32b. The phase adjuster 40 includes a number of phase shifters 40a corresponding to each of the plurality of antenna elements 32b. The phase adjuster 40 can adjust the relative phases of a plurality of signals by adjusting each phase shifter 40a, and can change the directing direction of the transmission / reception beam formed by the array antenna 32.
An antenna control device 38 is connected to the phase adjuster 40 of each array antenna 32. The antenna control device 38 has a function of controlling the directivity direction of the transmission / reception beam formed by the array antenna 32 for each transmission / reception tilt.

The antenna control device 38 is composed of a computer including a CPU and a storage device such as a memory and a hard disk. The storage device included in the antenna control device 38 stores a computer program or the like for execution by the CPU. When the CPU reads and executes this computer program, each function of the antenna control device 38 is realized.
The antenna control device 38 realizes the function of the antenna control device 38 by reading the program recorded on a computer-readable non-transient recording medium such as the storage device.

The antenna control device 38 controls the phase adjuster 40 by giving a control command to the phase adjuster 40. By controlling the phase adjuster 40, the antenna control device 38 causes the array antenna 32 to form a transmission / reception beam for each of the plurality of transmission / reception systems, and controls the direction of the transmission / reception beam.
The antenna control device 38 controls the directivity direction of the transmission / reception beam based on the directivity direction information given from the communication processing unit 20a of the radio control station 1.

Further, the antenna control device 38 is given light color information from the corresponding signal controller 12 via the line concentrator 10. The antenna control device 38 controls a variable range of the directivity direction of the transmission beam formed by the remote unit 2 according to the light color of the traffic signal 6. The antenna control device 38 determines a variable range of the directivity direction of the transmission beam according to the light color of the traffic signal 6.
The antenna control device 38 provides the variable range information to the aggregation device 20. The variable range information is information indicating a variable range in the directivity direction of the transmission beam defined by the antenna control device 38.
The communication processing unit 20a of the aggregation device 20 determines the directivity direction of the transmission beam when transmitting various data within the variable range of the directivity direction of the transmission beam indicated by the variable range information, and generates the directivity direction information.
The antenna control device 38 controls the directivity direction of the transmission beam within the variable range set by the antenna control unit 58b by controlling the directivity direction of the transmission / reception beam based on the directivity direction information from the aggregation device 20.
In this way, the antenna control device 38 is a transmission antenna control unit that changes the variable range of the directivity direction of the transmission beam formed by the four array antennas 32 (transmission antennas) of the remote unit 2 according to the light color of the traffic signal 6. To configure.
In the following description, the "variable range of the directivity direction of the transmission (reception) beam" may be referred to as the "variable range of the transmission (reception) beam" or simply the "variable range".

[About the configuration of the in-vehicle mobile station 4a]
FIG. 5A is a perspective view showing an example of the vehicle-mounted mobile station 4a.
The in-vehicle mobile station 4a includes a pyramid-shaped housing 44 and a first antenna module 46.
The first antenna module 46 is a device for wireless communication with a wireless control station 1 compliant with the fifth generation mobile communication system, and includes a plurality of array antennas 48.
A plurality of (four in the illustrated example) array antennas 48 are arranged so as to surround the side surface of the housing 44.
Each of the array antennas 48 includes a substrate 48a and a plurality of antenna elements 48b mounted on the substrate 48a. The antenna element 48b is, for example, a planar antenna such as a patch antenna.
Each array antenna 48 can perform beamforming with respect to a transmission beam and a reception beam by adjusting the phases of signals transmitted and received by a plurality of antenna elements 48b. Each array antenna 48 can form a beam in a range of an azimuth angle of about 90 degrees about the normal of the substrate 48a. As a result, the first antenna module 46 can form a beam directed in all directions of the own station 4a.
The first antenna module 46 has a function of transmitting and receiving radio waves to and from the remote unit 2 of the radio control station 1 while performing beamforming.

FIG. 5B is a block diagram showing an example of the configuration of the in-vehicle mobile station 4a.
As shown in FIG. 5B, the vehicle-mounted mobile station 4a includes a control device 50 and a second antenna module 52 in addition to the first antenna module 46. The control device 50 and the second antenna module 52 are housed inside the housing 44.
The second antenna module 52 has a function of transmitting and receiving radio waves to and from a radio control station compliant with the 4th generation mobile communication system. By including the second antenna module 52, the in-vehicle mobile station 4a can perform wireless communication conforming to the fourth generation mobile communication system.

The control device 50 includes an interface (IF) unit 54, a GPS (Global Positioning System) receiver 56, and a processing device 58. The IF unit 54 is provided between the first antenna module 46 and the second antenna module 52, and the processing device 58, and has a function of communicably connecting them. The GPS receiver 56 has a function of acquiring the position of the control device 50 (vehicle-mounted mobile station 4a) and giving it to the processing device 58.

The processing device 58 is composed of a computer including a CPU and a storage device such as a memory and a hard disk. The storage device included in the processing device 58 stores a computer program or the like for execution by the CPU. When the CPU reads and executes this computer program, each function of the processing device 58 is realized.
The processing device 58 realizes the function of the processing device 58 by reading the program recorded on a computer-readable non-transient recording medium such as the storage device.
The processing device 58 functionally includes a communication processing unit 58a and an antenna control unit 58b.

The communication processing unit 58a has a function of performing processing related to the baseband signal. The communication processing unit 58a supplies the baseband signal to the first antenna module 46 or the second antenna module 52. The baseband signal given to the first antenna module 46 or the second antenna module 52 is transmitted as a radio wave by the first antenna module 46 or the second antenna module 52. Further, the communication processing unit 58a receives the baseband signal given from the first antenna module 46 or the second antenna module 52.
Further, the communication processing unit 58a searches for and detects the remote unit 2 of the wireless control station 1 existing around the own station 4a by listening for the notification information which is the information necessary for the communication connection from the wireless control station. It has a function of performing a process for making a communication connection with the remote unit 2.

The antenna control unit 58b has a function of controlling the directivity of the transmission / reception beam formed by the first antenna module 46.
The antenna control unit 58b controls the phase adjuster 66 by giving a control command to the phase adjuster 66 (FIG. 6) included in the first antenna module 46. By controlling the phase adjuster 66, the antenna control unit 58b causes the first antenna module 46 to form a transmission / reception beam, and controls the directivity direction of the transmission / reception beam.
When searching for a remote unit 2 capable of communication connection, the antenna control unit 58b (reception antenna control unit) first antenna module 46 (reception antenna) according to the position of its own station 4a obtained from the GPS receiver 56. Has a function of changing the variable range of the received beam formed by.
Further, the antenna control unit 58b can memorize the position of the own station 4a over time and specify the traveling direction of the own station 4a. Further, the antenna control unit 58b can store the position of the own station 4a over time and obtain the mileage traveled by the own station 4a from a specific position to the current position.
Further, the storage device of the processing device 58 stores map information indicating the position and shape of the road R and the intersection I around the vehicle V. The map information includes information indicating a restricted area, which will be described later. The antenna control unit 58b can determine whether or not the own station 4a is within the restricted area based on this map information. The map information does not have to be stored in the processing device 58, and when the car navigation system of the vehicle V stores the map information, the antenna control unit 58b stores the map information from the car navigation system. You can refer to it.

FIG. 6 is a block diagram showing an example of the configuration of the first antenna module 46.
In FIG. 6, the first antenna module 46 includes four array antennas 48, a changeover switch 62, and a transceiver 64.
Each array antenna 48 is connected to the transceiver 64 via the changeover switch 62.

The transceiver 64 performs processing such as modulation and amplification on the baseband signal given from the communication processing unit 58a of the control device 50 to generate an RF signal. The generated RF signal is given to the array antenna 48 via the changeover switch 62.
Further, the transceiver 64 performs processing such as amplification and demodulation on the RF signal received by the array antenna 48 to generate a baseband signal. The generated baseband signal is given to the communication processing unit 58a.

The changeover switch 62 has a function of switching the connection destination of the transceiver 64 to any one of the four array antennas 48. The four array antennas 48 are switched according to the directivity direction of the transmission / reception beam. Therefore, wireless communication with the remote unit 2 is performed using any one of the four array antennas 48.
The array antenna 48 feeds the received radio wave from the remote unit 2 to the transceiver 64 as an RF signal. Further, the array antenna 48 radiates the RF signal given from the transceiver 64 into space as a radio wave.
The array antenna 48 further includes a phase adjuster 66 and a synthetic distributor 68 in addition to the plurality of antenna elements 48b.

The phase adjuster 66 adjusts the phases of a plurality of signals transmitted and received by the plurality of antenna elements 48b. The phase adjuster 66 includes a number of phase shifters 66a corresponding to each of the plurality of antenna elements 48b. The phase adjuster 66 can adjust the relative phases of a plurality of signals by adjusting each phase shifter 66a, and can change the directing direction of the transmission / reception beam formed by the array antenna 48.
A control command from the antenna control unit 58b is given to the phase adjuster 66 of each array antenna 48. The phase adjuster 66 adjusts each phase shifter 66a in response to this control command.
The control command from the antenna control unit 58b is also given to the changeover switch 62. The changeover switch 62 identifies the array antenna 48 to be connected to the transceiver 64 based on the control command.

[Communication connection processing]
FIG. 7 is a sequence diagram showing a process performed when the wireless control station 1 and the mobile station 4 communicate with each other.
As shown in FIG. 7, the radio control station 1 performs a process called beam sweeping (step S1).
Here, the beam sweeping is a process in which the radio control station 1 (remote unit 2) sequentially transmits broadcast information by a plurality of beams having different directivity directions. The radio control station 1 executes beam sweeping at regular intervals. By beam sweeping, the radio control station 1 can obtain the presence of a mobile station 4 that can be communicated and connected around the remote unit 2 and an appropriate direction of the beam directed to the mobile station 4. That is, the beam sweeping is a process of searching for a mobile station 4 capable of communication connection by changing the directivity direction of the transmission beam that transmits the broadcast information.

FIG. 8 is a diagram showing the directivity directions of the transmission / reception beams that can be formed by the remote unit 2 of the present embodiment. FIG. 8 shows the directivity direction of the transmission / reception beam formed by the remote unit 2 provided on the route r1 connected to the intersection I from the north direction. The arrow extending from the remote unit 2 in FIG. 8 is the directivity direction of the transmission / reception beam formed by the remote unit 2. In FIG. 8, the upper side of the paper is north and the lower side of the paper is south.

The remote unit 2 forms a transmission / reception beam directed in each directivity direction, as shown by a dotted line in FIG. The transmission / reception beam formed by the remote unit 2 is formed, for example, with a length of about 100 meters from the remote unit 2. That is, the transmission / reception range of the remote unit 2 is a range from the remote unit 2 to about 100 meters.
As shown in FIG. 8, the remote unit 2 of the present embodiment can form 12 transmission / reception beams having different directivity directions. The directivity direction of each beam is set to a direction determined by dividing the azimuth into 12 equal parts.
An index is set for each beam in each directivity direction.
In FIG. 8, # 1 is set as an index for the transmission / reception beam whose directivity is directed to the west. Further, # 2 is set as an index for the transmission / reception beam whose directivity direction is west-northwest, and # 3 is set as an index for the transmission / reception beam whose directivity direction is northwest. In this way, each beam is indexed from # 1 to # 12 in order clockwise along the azimuth direction.

The communication processing unit 20a of the wireless control station 1 provides the remote unit 2 with the index associated with each predetermined unit as the directivity direction information. That is, the communication processing unit 20a specifies the directivity direction of the transmission / reception beam formed in the remote unit 2 by using the index.
An index is also set for the transmission / reception beam formed by the other remote unit 2. That is, even in the transmission / reception beam formed by the other remote unit 2, # 2 is set as an index for the transmission / reception beam whose directivity direction is west-northwest, and # 1 to # 12 are sequentially clockwise along the azimuth direction. Index is set.
The elevation angle direction of each beam is appropriately set so as to be able to transmit and receive to and from the mobile station 4 at a position along the azimuth angle direction.

FIG. 9 is a diagram showing an example of a downlink radio frame by the radio control station 1.
As shown in FIG. 9, 12 regions b1 to b12 for transmitting the broadcast information transmitted by beam sweeping are secured in the radio frame F by the radio control station 1. These regions b1 to b12 are regions called SS / PBCH (Synchronization Signal / Physical Broadcast Channel) blocks. Hereinafter, the regions b1 to b12 are also referred to as blocks b1 to b12.
The blocks b1 to b12 are arranged side by side in the time axis direction, and are periodically transmitted at a predetermined period P. This period P is, for example, 20 milliseconds.

The synchronization signal and the broadcast information are stored in the blocks b1 to b12. Both the synchronization signal and the broadcast information include information necessary for communication connection. The broadcast information includes identification information for identifying a block in which the broadcast information is stored. As will be described later, the mobile station 4 that has received the broadcast information transmits the minimum information (random access preamble) to the radio control station 1 based on the identification information included in the broadcast information. Further, when the wireless control station 1 receives the random access preamble, the wireless control station 1 can recognize that there is a mobile station 4 capable of communication connection around the own station 1 (remote unit 2), and the mobile station can perform communication. It is possible to recognize which of the blocks b1 to b12 the received block is based on the random access preamble.

The communication processing unit 20a of the wireless control station 1 can select a transmission beam for transmitting each block b1 to b12 from the indexes # 1 to # 12. For example, when it is allowed to change the directivity direction of the transmission beam over the entire azimuth direction in a certain remote unit 2, the communication processing unit 20a has blocks b1 to b12 and an index # as shown in FIG. The beams 1 to # 12 are associated with each other, and the beam corresponding to each of the blocks b1 to b12 is selected as the transmission beam.
In FIG. 9, the communication processing unit 20a selects the beam of index # 1 as the transmission beam of block b1, the beam of index # 2 as the transmission beam of block b2, and the index # 3 as the transmission beam of block b3. Select the beam and select the beam of index # 12 as the transmission beam of block b12.
The communication processing unit 20a generates directivity information so that the blocks b1 to b12 are transmitted by the selected transmission beam, and supplies the directivity information to the remote unit 2.
The remote unit 2 to which the directivity information is given transmits the blocks b1 to b12 by the beam of the selected index.
In this way, the radio control station 1 performs beam sweeping by transmitting the blocks b1 to b12 by transmission beams having different directivity directions.

Returning to FIG. 7, the radio control station 1 transmits the synchronization signal and the broadcast information by beam sweeping as described above (step S1).
At the same time, the mobile station 4 which is not in communication with the wireless control station 1 searches for the remote unit 2 of the wireless control station 1 (step S2).
The search for the remote unit 2 of the wireless control station 1 performed by the mobile station 4 means that the mobile station 4 sequentially forms a plurality of received beams having different directivity directions, and the broadcast information transmitted from the remote unit 2 of the wireless control station 1 is transmitted. This is a process that waits for reception. By this process, the mobile station 4 searches for the remote unit 2 of the wireless control station 1 that can be connected to the communication.

FIG. 10 is a diagram showing a directivity direction of a transmission / reception beam that can be formed by the vehicle-mounted mobile station 4a of the vehicle V. The arrow extending from the vehicle-mounted mobile station 4a in FIG. 10 is the directivity direction of the transmission / reception beam formed by the vehicle-mounted mobile station 4a.
The in-vehicle mobile station 4a forms a transmission / reception beam directed in each directivity direction. As shown in FIG. 10, the vehicle-mounted mobile station 4a of the present embodiment can form 12 transmission / reception beams having different directivity directions. The directivity direction of each beam is set in a direction determined by dividing the beam into 12 equal parts at an equal angle in the azimuth direction.
Similar to the radio control station 1, each beam is indexed for each directivity direction.
In FIG. 10, # 1 is set as an index for the transmission / reception beam whose directivity direction is in the traveling direction of the vehicle V. Further, when the vehicle V is viewed from above, indexes from # 1 to # 12 are set for each beam in order clockwise along the azimuth direction.

The in-vehicle mobile station 4a changes the directing direction of the reception beam by using a part or all of the reception beams of indexes # 1 to # 12 in a state where the communication connection is not made with the wireless control station 1. Search for a possible remote unit 2.
The mobile terminal 4b also performs the same processing.

Returning to FIG. 7, when the mobile station 4 receives the synchronization signal and the broadcast information transmitted by the wireless control station 1 by beam sweeping (step S3), the mobile station 4 recognizes the existence of the remote unit 2 capable of communication connection. At the same time, the directing direction of the beam directed to the remote unit 2 can be acquired depending on the directing direction of the received beam when the broadcast information is received (step S4).
For example, when the mobile station 4 receives a plurality of broadcast information by a plurality of received beams having different directivity directions, the mobile station 4 remotely determines the directivity direction of the received beam that has received the broadcast information having the highest reception quality such as received power. Acquired as the directivity direction toward the unit 2. As a result, the mobile station 4 can acquire the most appropriate directivity direction as the directivity direction toward the remote unit 2.

Next, the mobile station 4 transmits a random access preamble to the radio control station 1 based on the identification information included in the broadcast information (step S5). The mobile station 4 transmits the random access preamble by the PRACH (Physical Random Access Channel) assigned to the uplink radio frame.
For example, when each block b1 to b12 is associated with 12 different regions provided in the uplink radio frame for PRACH, the region for PRACH corresponding to each block b1 to b12 is associated. Information indicating the above can be used as identification information. The mobile station 4 transmits a random access preamble using the area for PRACH indicated by the identification information included in the received broadcast information.
The radio control station 1 that has received the random access preamble determines which block of the blocks b1 to b12 is received by the mobile station 4 that has received the random access preamble from the area used for transmitting the random access preamble. Can be recognized.
The radio control station 1 can acquire the directivity direction of the beam directed to the mobile station 4 from the directivity direction of the transmission beam used for transmission of each block b1 to b12 (step S6).

Next, the radio control station 1 transmits a random access response including a random access preamble transmitted from the mobile station 4, timing information, scheduling information, and the like to the mobile station 4 (step S7).
After that, information is repeatedly exchanged between the wireless control station 1 and the mobile station 4, and a communication connection is established between the wireless control station 1 and the mobile station 4 (step S8).
Note that establishing a communication connection means establishing a state in which communication data can be transmitted and received to and from each other by performing the above-mentioned processing with a specific communication destination.

Next, the mobile station 4 determines whether or not to maintain communication with the radio control station 1 (step S9).
The mobile station 4 determines whether or not to maintain the communication based on the reception quality of the broadcast information from the wireless control station 1. The mobile station 4 receives the broadcast information even while communicating with the wireless control station 1, and searches for an appropriate direction toward the remote unit 2 based on the received broadcast information. Further, the radio control station 1 also searches for an appropriate directivity direction toward the mobile station 4 based on the information from the mobile station 4. As a result, the remote unit 2 of the wireless control station 1 and the mobile station 4 maintain a communication connection while directing the directivity directions of the beams to each other.

For example, when the mobile station 4 determines that the received power of the broadcast information from the wireless control station 1 is smaller than the predetermined value, the mobile station 4 determines that the communication with the wireless control station 1 is not maintained, and the received power of the broadcast information is predetermined. If it is determined to be equal to or higher than the value, communication with the wireless control station 1 is maintained.
If it is determined that the communication with the wireless control station 1 is not maintained, the mobile station 4 disconnects the communication with the wireless control station 1 (step S10).

[Control of variable range of transmitted beam by wireless control station 1]
The wireless control station 1 of the present embodiment has a function of controlling a variable range of a transmission beam by the remote unit 2 according to the light color of the traffic signal 6. Here, the control of one remote unit 2 by the wireless control station 1 will be described, but the wireless control station 1 performs the same control for each remote unit 2.
The antenna control device 38 included in the remote unit 2 controls the variable range of the transmission beam by the remote unit 2.

FIG. 11 is a flowchart showing the control of the variable range of the transmission beam by the remote unit 2 performed by the antenna control device 38.
As described above, the antenna control device 38 is given light color information from the traffic signal 6 corresponding to the remote unit 2.
First, the antenna control device 38 refers to the light color information and determines whether or not the light color of the traffic signal 6 is blue (step S11).
When it is determined in step S11 that the light color of the traffic signal 6 is not blue (when it is red or yellow), the antenna control device 38 executes the normal mode (step S12) and returns to step S11.

In the normal mode, the antenna control device 38 provides the communication processing unit 20a of the aggregation device 20 with variable range information indicating that the variable range of the transmission beam is the entire range in the azimuth direction (first transmission range).
As a result, the communication processing unit 20a of the aggregation device 20 transmits various information including broadcast information using all the transmission beams having indexes # 1 to # 12. In this case, the communication processing unit 20a transmits the blocks b1 to b12 by transmission beams having different directivity directions (transmission beams having indexes # 1 to # 12) as shown in FIG.
The variable range information can be used as an index of usable transmission beams. In this case, the variable range information indicating the entire range in the azimuth direction is the index # 1 to # 12 of the beam. The variable range information can also be a range of azimuth angles.

In the normal mode, the broadcast information is transmitted over the entire range of the remote unit 2 in the azimuth direction.
As a result, the wireless control station 1 searches for the mobile station 4 existing in the entire range in the azimuth angle direction of the remote unit 2 in the normal mode, and makes a communication connection.

On the other hand, if it is determined in step S11 that the light color of the traffic signal 6 is blue, the antenna control device 38 executes the restriction mode (step S13) and returns to step S11.

In the limiting mode, the antenna control device 38 collects variable range information indicating that the variable range of the transmission beam is a limited range (second transmission range) limited so as to be narrower than in the normal mode. It is given to the communication processing unit 20a.
As a result, the communication processing unit 20a of the aggregation device 20 transmits various information including broadcast information using only the transmission beam included in the limited range among the beams having indexes # 1 to # 12.
Here, the limiting range is set to a range that limits the usable transmission beam to a beam along the road R (direction) where entry to the intersection I can be permitted by the light color of the traffic signal 6. As a result, the road R where the entrance to the intersection I is permitted by the light color of the traffic signal 6 is covered as the service area.

For example, when the light color of the traffic signal 6 in FIG. 8 is blue, the restriction range is limited to the transmission beam whose directivity direction is directed from the north direction to the extension direction of the route r1 connected to the intersection I. The range. In FIG. 8, it is assumed that the beams directed in the extending direction of the route r1 are the beams having indexes # 3, # 4, # 10, and # 11. In this case, the limiting range includes the directivity of the beam of index # 3 and the directivity of the beam of index # 4 among the azimuth directions. The range W2 is limited to include the direction and the directivity of the beam at index # 11.
In this case, the antenna control device 38 gives the beam indexes # 3, # 4, # 10, and # 11 to the communication processing unit 20a as variable range information.
The communication processing unit 20a of the aggregation device 20 to which the variable range information is given generates directional information for transmitting various information including the broadcast information by using the transmission beam within the limited range. That is, in the directivity direction information in this case, the transmission beam for causing the remote unit 2 to perform transmission is any of the transmission beams having indexes # 3, # 4, # 10, and # 11.
As described above, the beam directed in the extending direction of the route (road) includes a beam along the extending direction of the route and a direction intersecting the extending direction of the route. It may contain beams that do not deviate significantly from the road.

FIG. 12 is a diagram showing an example of a downlink radio frame by the radio control station 1 in the restricted mode.
In FIG. 12, the configuration of the wireless frame F is the same as in the normal mode.
However, in the limited mode, the communication processing unit 20a transmits the broadcast information by the transmission beam within the limited range indicated by the variable range information.
As described above, the transmitting beam within the limiting range is limited to the transmitting beams having indexes # 3, # 4, # 10, and # 11. The communication processing unit 20a transmits blocks b1 to b12 using only transmission beams having indexes # 3, # 4, # 10, and # 11.
For example, as shown in FIG. 12, the communication processing unit 20a selects the transmission beam of index # 3 as the transmission beam of block b1, selects the transmission beam of index # 4 as the transmission beam of block b2, and selects the transmission beam of index # 4 as the transmission beam of block b3. The transmit beam of index # 10 is selected as the transmit beam, and the transmit beam of index # 11 is selected as the transmit beam of block b4.
In this way, the communication processing unit 20a allocates the transmission beams of blocks b1 to b12 from among the transmission beams having indexes # 3, # 4, # 10, and # 11, and uses these four transmission beams to block b1 to blocks b1 to. b12 is transmitted.

In the restriction mode, the broadcast information is transmitted in the azimuth angle direction of the remote unit 2 within the range reached by the transmission beam within the restriction range.
As a result, the wireless control station 1 searches for the mobile station 4 existing in the limited range in the azimuth angle direction of the remote unit 2 in the restricted mode, and makes a communication connection.

For example, in FIG. 8, when various information including broadcast information is transmitted by the beams having indexes # 3, # 4, # 10, and # 11, the radio control station 1 exists in a range that can be transmitted and received by these four beams. Search for the mobile station 4 to be used, and make a communication connection.

FIG. 13 is a diagram showing an example of a variable range of a beam set in each remote unit 2 at an intersection I. Also in FIG. 13, the upper side of the paper surface is north and the lower side of the paper surface is south.
In FIG. 13, the light color of the traffic signal 6a provided on the road r1 connected to the intersection I from the north direction and the light color of the traffic light 6c provided on the road r3 connected to the intersection I from the south direction are blue. , The traffic light 6b provided on the road r2 connecting from the west to the intersection I is red, and the traffic light 6d provided on the road r4 connecting from the east to the intersection I is red. Shows the case.

The normal mode is executed in the remote units 2b and 2d corresponding to the traffic signals 6b and 6d whose light color is red. Therefore, the variable range of the beams of the remote units 2b and 2d is the entire range in the azimuth direction as shown in FIG. In this case, the remote units 2b and 2d search for the mobile station 4 existing in the entire range of the remote units 2b and 2d in the azimuth direction. In FIG. 13, the circular line figure surrounding the remote unit 2 indicates that the variable range of the beam is the entire range in the azimuth direction.

On the other hand, in the remote units 2a and 2c corresponding to the traffic signals 6a and 6c whose light color is blue, the restriction mode is executed. Therefore, as shown in FIG. 13, the variable range of the beams of the remote units 2a and 2c is the beam along the extending direction of the road r1 and the road r3 that are allowed to enter the intersection I in the azimuth angle direction. Is set in a limited range so that
The remote units 2a and 2c search for the mobile station 4 existing in the range where the beam is formed on the road r1 and the road r3 in the azimuthal directions of the remote units 2a and 2c.
The remote unit 2a transmits various information including notification information using beams having indexes # 3, # 4, # 10, and # 11, and the remote unit 2c has indexes # 4, # 5, # 9, and #. Various information including notification information is transmitted using the 10 beams.

In this case, since the remote units 2a and 2c do not form a transmission beam on the road R in a range other than the directions r1 and r3, the in-vehicle mobile station 4a mainly enters the intersection I from the direction r1 and passes through the intersection I. To explore. Further, the remote unit 2c mainly searches for the vehicle-mounted mobile station 4a that enters the intersection I from the route r3 and passes through the intersection I.

The variable range of the beam shown in FIG. 13 is changed by switching the light color of each traffic signal 6. If the light colors of the traffic lights 6a and 6c are switched to red and the light colors of the other traffic lights 6b and 6d are switched to blue, the remote units 2a and 2b execute the normal mode, and the remote units 2b and 2d are in the restricted mode. Is executed.

In the above configuration, when the travel of the corresponding route is permitted by the green light, the remote unit 2 forms a transmission beam and the search range is limited to the route where the travel is permitted, and the vehicle-mounted mobile station 4a on the route is restricted. You can increase the chances of exploring. As a result, it is possible to effectively search for the in-vehicle mobile station 4a that is allowed to travel by the green light and passes through the direction in a short time.
When the in-vehicle mobile station 4a is stopped at a red light, there is time to spare, so that the remote unit 2 has an azimuth of the remote unit 2 when the travel of the corresponding direction is not permitted by the red light. The mobile station 4 existing in the entire range in the angular direction is searched.

According to the system having the above configuration, the radio control station 1 is changed so as to narrow the variable range of the transmission beam according to the movement mode of the vehicle-mounted mobile station 4a which is stopped or moved depending on the light color of the traffic signal 6. be able to. As a result, the time required to search for the in-vehicle mobile station 4a can be shortened as necessary.
That is, if the variable range of the transmission beam is changed from the entire range to the limited range, the time required to search the in-vehicle mobile station 4a can be shortened as compared with the case of the entire range, and wireless communication can be started promptly. be able to.

If there is a delay in starting wireless communication between the wireless control station 1 and the mobile station 4, for example, if the mobile station 4 is an in-vehicle mobile station 4a mounted on a vehicle V traveling on a road, the in-vehicle mobile station The time required for wireless communication between 4a and the wireless control station 1 is squeezed, and the communication efficiency is lowered.
On the other hand, according to the present embodiment, since wireless communication can be started promptly, a decrease in communication efficiency can be suppressed.

[Control of variable range of received beam by in-vehicle mobile station 4a]
When searching for a wireless control station 1 (remote unit 2) capable of communication connection, the vehicle-mounted mobile station 4a (antenna control unit 58b) of the present embodiment responds to the position of the vehicle-mounted mobile station 4a (vehicle V). It has a function to control the variable range of the received beam.
FIG. 14 is a flowchart showing the control of the variable range of the received beam performed by the in-vehicle mobile station 4a.

First, the vehicle-mounted mobile station 4a determines whether or not it is in communication connection with the wireless control station 1 (step S21).
When determining that the wireless control station 1 is in communication connection, the vehicle-mounted mobile station 4a repeats step S21 again. Therefore, the in-vehicle mobile station 4a repeats step S21 until it is determined that the in-vehicle mobile station 4a is not connected to the wireless control station 1 by communication. When communicating with the wireless control station 1, the vehicle-mounted mobile station 4a does not need to search for the remote unit 2 and does not need to control the variable range of the received beam. Therefore, when it is determined that the wireless control station 1 is in communication connection, the vehicle-mounted mobile station 4a does not proceed with the variable range control process.

If it is determined in step S21 that the communication is not connected to the wireless control station 1, the vehicle-mounted mobile station 4a determines whether or not the position of the vehicle-mounted mobile station 4a is within the restricted area (step S22).
The restricted area (predetermined area) is an area set on the upstream side of the intersection I where the remote unit 2 of the wireless control station 1 is installed. Therefore, when traveling toward the intersection I located in front of the vehicle-mounted mobile station 4a in the traveling direction, the vehicle-mounted mobile station 4a enters the restricted area before reaching the intersection I.
The upstream side of the intersection I is the front side of the intersection I located in front of the vehicle-mounted mobile station 4a, and includes the range from the position of the vehicle-mounted mobile station 4a to the intersection I.
The traveling direction of the vehicle-mounted mobile station 4a is the traveling direction when the vehicle-mounted mobile station 4a moves along the road R.
The front of the vehicle-mounted mobile station 4a in the traveling direction means the front of the vehicle-mounted mobile station 4a when the vehicle-mounted mobile station 4a advances along the traveling direction.

When it is determined in step S22 that the position of the vehicle-mounted mobile station 4a is outside the restricted area, the vehicle-mounted mobile station 4a executes the normal mode (step S23) and returns to step S21.
In the normal mode, the vehicle-mounted mobile station 4a sequentially uses 12 reception beams of indexes # 1 to # 12 to change the directivity direction of the reception beams, and searches for the remote unit 2 capable of communication connection. That is, in the normal mode, the vehicle-mounted mobile station 4a sets the variable range of the reception beam to the entire range in the azimuth direction (first reception range).
The elevation angle direction of each beam is appropriately set so as to be able to transmit and receive to and from the radio control station 1 at a position along the azimuth angle direction.

On the other hand, when it is determined in step S22 that the position of the vehicle-mounted mobile station 4a is outside the restricted area, the vehicle-mounted mobile station 4a executes the restricted mode (step S24) and returns to step S21.
In the limited mode, the vehicle-mounted mobile station 4a changes the directivity direction of the received beam by sequentially using three received beams of indexes # 1, # 2, and # 12, which are beams whose directivity directions are directed in the traveling direction of the vehicle-mounted mobile station 4a. Then, the remote unit 2 that can be connected to the communication is searched. That is, in the limited mode, the in-vehicle mobile station 4a sets the variable range of the received beam to a limited range (second reception range) narrower than the entire range.

FIG. 15 is a flowchart showing an example of processing in the restricted mode.
In the limiting mode, the vehicle-mounted mobile station 4a first sets the variable range of the received beam to the limiting range (step S31).
The limiting range is the range in the azimuth angle direction. The limiting range is set to a range in which the directivity direction of the received beam is limited to the beam directed in the traveling direction of the vehicle-mounted mobile station 4a. As a result, the in-vehicle mobile station 4a changes the directivity direction of the reception beam by sequentially using the three reception beams as described above, and mainly searches for the remote unit 2 located in front of the travel direction of the own station 4a. .. In the present embodiment, the reception beams whose directivity directions are directed in the traveling direction of the vehicle-mounted mobile station 4a are three reception beams having indexes # 1, # 2, and # 12 (FIG. 10).
The receiving beam whose directing direction is directed to the traveling direction of the vehicle-mounted mobile station 4a includes the receiving beam whose directing direction is along the traveling direction and when the range of the azimuth angle centered on the traveling direction is less than 180 degrees. May include a received beam whose directional direction is within its azimuth.

Next, the vehicle-mounted mobile station 4a determines whether or not it is in communication connection with the wireless control station 1 (step S32).
When it is determined that the wireless control station 1 is in communication connection, the in-vehicle mobile station 4a ends the process.
When it is determined to not communicating connected to the radio control station 1, the vehicle-mounted mobile station 4a, after own station 4a enters into the restricted area, it is determined whether the vehicle has traveled a predetermined distance K ₂ (step S33 ). The distance K ₂ is set to be shorter than the distance from the upstream end of the restricted area to the intersection I.

In step S33, if it is determined that no traveling distance K ₂ is a predetermined travel distance, the vehicle-mounted mobile station 4a, the process returns to step S32 again. Therefore, when the state can not communicate connected to the radio control station 1 continues, vehicle mobile station 4a repeats the step S33 until the running distance K _2.
If it is determined that traveling distance K ₂ in step S33, the vehicle-mounted mobile station 4a, the process proceeds to step S34, index # 6, # 7, change the orientation of the receive beam sequentially with three receiving beams # 8 Then, the remote unit 2 that can be connected to the communication is searched. That is, in step S34, the vehicle-mounted mobile station 4a changes the variable range of the received beam so that the directivity direction is limited to the received beam directed in the direction opposite to the traveling direction of the vehicle-mounted mobile station 4a (behind the vehicle-mounted mobile station 4a). To do. As a result, the in-vehicle mobile station 4a searches for the remote unit 2 located behind the own station 4a.

Accordingly vehicle mobile station 4a is from enters the restricted area until the travel distance K _2, carries out the search of the remote unit 2 located forward in the traveling direction of the own station 4a, the distance K ₂ or more runs the own station The remote unit 2 located behind 4a is searched.
The receiving beam whose directing direction is directed to the rear of the vehicle-mounted mobile station 4a includes the receiving beam whose directing direction is opposite to the traveling direction and the range of the azimuth angle when centered in the opposite direction is 180 degrees. When less than, a received beam whose direction is within the range of the azimuth may be included.

Next, the vehicle-mounted mobile station 4a proceeds to step S35 and determines whether or not at least one of the following two conditions is satisfied (step S35).
Condition 1: The wireless control station 1 is connected by communication.
Condition 2: own station 4a is progressing after passing through the intersection I predetermined distance K _3.

If at least one of these two conditions is not met, the vehicle-mounted mobile station 4a repeats step S35. If at least one of the two conditions is satisfied, the in-vehicle mobile station 4a ends the process.
The distance K ₃ is set to the same distance as the distance K _1.

FIG. 16 is a diagram for explaining a variable range of the reception beam of the vehicle-mounted mobile station 4a traveling on the road R.
FIG. 16 shows a case where the vehicle-mounted mobile station 4a (vehicle V) travels from the position A toward the intersection I where the remote unit 2 is installed.
As described above, the remote unit 2 transmits various information including broadcast information by the transmission beam.
Further, a restricted area is set on the upstream side of the intersection I located in front of the vehicle-mounted mobile station 4a in the traveling direction. The restricted area is from the intersection I, which is an area that is set on the road of a distance K ₁ just upstream the upstream end L1.
The restricted area is set according to, for example, the transmission / reception range of the remote unit 2. Therefore, for example, the distance K ₁ is set to about 100 meters.

The in-vehicle mobile station 4a can obtain the position of the own station 4a from the GPS receiver 56. Further, the position of the intersection I and the position of the remote unit 2 can be stored in advance in the storage device of the processing device 58 of the vehicle-mounted mobile station 4a, and the vehicle-mounted mobile station 4a communicates wirelessly by the second antenna module 52. It can also be obtained from the outside.
Further, when the vehicle-mounted communication device 16 is communicably connected to the processing device 58, the position of the intersection I and the position of the remote unit 2 can be acquired from the roadside wireless communication device 14 via the vehicle-mounted communication device 16. ..
The in-vehicle mobile station 4a controls the variable range of the received beam based on these positions.

In FIG. 16, when the in-vehicle mobile station 4a is in the position A, the in-vehicle mobile station 4a is outside the restricted area, and therefore, if it is not connected to the wireless control station 1 by communication, the normal mode is executed (in FIG. 14). Step S23). Therefore, the variable range of the received beam is the entire range in the azimuth angle direction as shown in FIG. In addition, in FIG. 16, the circular line figure surrounding the periphery of the vehicle-mounted mobile station 4a indicates that the variable range of the beam is the entire range in the azimuth direction.

Next, when the vehicle-mounted mobile station 4a advances to the position B, the vehicle-mounted mobile station 4a is within the restricted area, and therefore, if the communication connection with the wireless control station 1 is not established, the restricted mode is executed (step S24 in FIG. 14). ). Further, the vehicle-mounted mobile station 4a does not reach from the upstream end L1 of the restricted area to the middle point L2 distance K ₂ to the downstream side. Therefore, as shown in FIG. 16, the variable range of the received beam in this case is a limited range that allows only the beam directed in the traveling direction in the azimuth angle direction (step S31 in FIG. 15). Therefore, the in-vehicle mobile station 4a searches for the remote unit 2 located in front of the own station 4a in the traveling direction.

If communication connection with the front of the remote unit 2 during the period from the upstream end L1 to progression distance K ₂ to the downstream side, the vehicle-mounted mobile station 4a is not necessary to search for the remote unit 2. Therefore, the in-vehicle mobile station 4a ends the restriction mode (step S32 in FIG. 15).
On the other hand, when the vehicle-mounted mobile station 4a passes through the intermediate point L2 without being able to communicate with the remote unit 2 (position C), the vehicle-mounted mobile station 4a is limited to the reception beam whose directivity is directed to the rear of the vehicle-mounted mobile station 4a. The variable range of the received beam is changed so as to be (step S34 in FIG. 15). As a result, the in-vehicle mobile station 4a searches for the remote unit 2 located behind the own station 4a.
The variable range in this case is set to a range that limits the received beam to a beam whose directivity direction is directed to the rear of the vehicle-mounted mobile station 4a (beams of indexes # 6, # 7, and # 8) in the azimuth angle direction.

If the wireless control station 1 cannot be found in the restricted area and the communication connection with the remote unit 2 cannot be established, it is possible that an obstacle blocking the transmission beam and the reception beam from the remote unit 2 exists in front of the vehicle-mounted mobile station 4a. ..

FIG. 17 is a diagram showing a state in which a truck is traveling in front of the vehicle-mounted mobile station 4a.
As shown in FIG. 17, when a tall truck T travels in front of the vehicle-mounted mobile station 4a, the truck T becomes an obstacle and the transmission beam from the remote unit 2 and the reception beam of the vehicle-mounted mobile station 4a become obstacles. It may be blocked.

In such a case, if the truck T passes through the intersection I and the remote unit 2, the truck T is no longer an obstacle between the remote unit 2 and the vehicle-mounted mobile station 4a.
Therefore, the in-vehicle mobile station 4a changes the variable range to a range facing backward (opposite direction in the traveling direction), so that if the receiving beam is directed backward, after passing through the intersection I and the remote unit 2. , The remote unit 2 at the rear position can be quickly searched.

Returning to FIG. 16, then, from the vehicle-mounted mobile station 4a is waypoint L2, to be able communication connection with the remote unit 2 during the period from the intersection I to the point L3 advanced a predetermined distance K ₃ to the downstream side, vehicle movement The station 4a maintains a state in which the variable range of the reception beam is limited to the reception beam directed to the rear of the vehicle-mounted mobile station 4a.
When the vehicle-mounted mobile station 4a passes the point L3 and reaches the position D without being able to communicate with the remote unit 2, the vehicle-mounted mobile station 4a executes the normal mode (step S23 in FIG. 14). Therefore, the variable range of the received beam is the entire range in the azimuth angle direction as shown in FIG.

In this case, until the proceeds from through the intersection I distance K _3, vehicle mobile station 4a can continue searching for the remote unit 2 which is a rear position of the own station 4a. As a result, it is possible to leave the possibility of being able to communicate with the remote unit 2 after passing through the intersection I.

According to the vehicle-mounted mobile station 4a having the above configuration, when the vehicle-mounted mobile station 4a searches for the remote unit 2 of the wireless control station 1, the variable range of the received beam is changed according to the position of the vehicle-mounted mobile station 4a.
That is, the in-vehicle mobile station 4a sets the variable range to the entire range in the azimuth direction when the position of the in-vehicle mobile station 4a is outside the restricted area, and sets the variable range when the position of the in-vehicle mobile station 4a is within the restricted area. Make it a narrower limit.

Therefore, the in-vehicle mobile station 4a has an area around the own station 4a where it is clear that the remote unit 2 does not exist, or when wireless communication is performed with the remote unit 2 located in a certain direction. Can be configured to select a limited range with a narrow variable range. As a result, the time required to search for the remote unit 2 can be shortened, and wireless communication can be started promptly.

Further, in the above embodiment, the area on the upstream side of the remote unit 2 installed in front of the vehicle-mounted mobile station 4a in the traveling direction is set as the restricted area, and the limited range of the variable range is set as the traveling direction of the vehicle-mounted mobile station 4a. Since the range is limited to the reception beam directed in the direction, the vehicle-mounted mobile station 4a can search the remote unit 2 by narrowing the variable range in the traveling direction if the vehicle enters the restricted area. As a result, the in-vehicle mobile station 4a can quickly search for the remote unit 2 and can quickly start wireless communication with the remote unit 2.

[Other]
It should be noted that the embodiments disclosed this time are exemplary in all respects and are not restrictive.
In the present embodiment, the case where the remote unit 2 is installed at the intersection I is illustrated, but the remote unit 2 may be installed at a place other than the intersection on the road R. In this case, a restricted area is set on the upstream side of the remote unit 2.
In this case, the upstream side of the remote unit 2 is the front side of the remote unit 2 located in front of the vehicle-mounted mobile station 4a, and includes the range from the position of the vehicle-mounted mobile station 4a to the remote unit 2.
Further, the restricted area may be installed at an intersection where the remote unit 2 is not installed. In this case, if the vehicle-mounted mobile station 4a approaches the intersection, the vehicle-mounted mobile station 4a will switch from the normal mode to the restricted mode regardless of the installation of the remote unit 2.
Therefore, the in-vehicle mobile station 4a can switch from the normal mode to the restricted mode as long as it has the position of the intersection, and when the information on the installation of the remote unit 2 cannot be obtained or at the introduction stage of the remote unit 2, the vehicle-mounted mobile station 4a can switch to the restricted mode. Even when an intersection where the remote unit 2 is installed and an intersection where the remote unit 2 is not installed are mixed, if the remote unit 2 is installed at the intersection, it can be appropriately dealt with.

The scope of the present disclosure is indicated by the scope of claims, not the above-mentioned meaning, and is intended to include the meaning equivalent to the scope of claims and all changes within the scope.

1 Wireless control station 2, 2a, 2b, 2c, 2d Remote unit 4 Mobile station 4a In-vehicle mobile station 4b Mobile terminal 6, 6a, 6b, 6c, 6d Traffic signal 7 Prop 10 Concentrator 11 Optical transmission line 12 Signal controller 14 Roadside wireless communication device 16 In-vehicle communication device 18 Concentrator 20 Concentrator 20a Communication processing unit 22 ITS communication device 24 Central control device 30 Housing 32 Array antenna 32a Board 32b Antenna element 34 Composite distributor 36 Transmitter / receiver 38 Antenna control device 40 Phase adjuster 40a Phase shifter 44 Housing 46 First antenna module 48 Array antenna 48a Substrate 48b Antenna element 50 Control device 52 Second antenna module 54 IF unit 56 GPS receiver 58 Processing device 58a Communication processing unit 58b Antenna control unit 62 Changeover switch 64 Transmitter / receiver 66 Phase adjuster 66a Phase adjuster 68 Synthetic distributor B Station building F Wireless frame H Pedestrian I Intersection K ₁ distance K ₂ distance K ₃ distance L1 Upstream end L2 Intermediate point L3 Point NW1 Core network NW2 network P period R Road T Truck V Vehicle W1 Range W2 Range b1 to b12 Block r1, r2, r3, r4 Direction

Claims (16)

1. A wireless control station that sends information necessary for communication connection,
   A mobile communication system including an in-vehicle mobile station that waits for the information while changing the directivity direction of the received beam.
   The in-vehicle mobile station
   The receiving antenna forming the receiving beam and
   A mobile communication system including a receiving antenna control unit that changes a variable range of the directivity of the receiving beam according to the position of the vehicle-mounted mobile station.
2. The receiving antenna control unit sets the variable range as the first reception range when the position of the vehicle-mounted mobile station is outside the predetermined area, and sets the variable range when the position of the vehicle-mounted mobile station is within the predetermined area. The mobile communication system according to claim 1, wherein the second reception range is narrower than the first reception range.
3. The mobile communication system according to claim 2, wherein the predetermined area is an area set on the upstream side of an intersection located in front of the vehicle-mounted mobile station in the traveling direction.
4. The wireless control station includes a remote unit installed on the road and capable of communicating with the in-vehicle mobile station.
   The mobile communication system according to claim 2, wherein the predetermined area is an area set on the upstream side of the remote unit located in front of the vehicle-mounted mobile station in the traveling direction.
5. The mobile communication system according to claim 3 or 4, wherein the second reception range is a range in which the directivity direction of the reception beam is limited to a beam directed in the traveling direction of the vehicle-mounted mobile station.
6. When the in-vehicle mobile station cannot receive the information while the in-vehicle mobile station travels by a predetermined mileage after entering the predetermined area, the receiving antenna control unit has a directing direction of the in-vehicle mobile station. The mobile communication system according to any one of claims 3 to 5, wherein the variable range is changed so as to be limited to a reception beam directed in a direction opposite to the traveling direction.
7. The mobile communication system according to claim 6, wherein the receiving antenna control unit changes the variable range to the first receiving range when the vehicle-mounted mobile station moves out of the predetermined area and then travels by a predetermined distance.
8. The wireless control station
   A transmitting antenna that transmits the information while changing the directivity direction of the transmitting beam, and
   The mobile communication system according to claim 1, further comprising a transmission antenna control unit that changes a variable range of the directivity direction of the transmission beam according to the light color of a traffic signal installed on a road on which the vehicle-mounted mobile station moves. ..
9. In-vehicle mobile station and
   A mobile communication system including a wireless control station that transmits information necessary for communication connection with the in-vehicle mobile station while changing the directivity direction of a transmission beam.
   The wireless control station
   The transmitting antenna forming the transmitting beam and
   A mobile communication system including a transmission antenna control unit that changes a variable range of the directivity direction of the transmission beam according to the light color of a traffic signal installed on a road on which the vehicle-mounted mobile station moves.
10. The mobile communication system according to claim 9, wherein the transmission antenna control unit changes the variable range to either a first transmission range or a second transmission range narrower than the first transmission range.
11. The mobile communication system according to claim 10, wherein the second transmission range is a range in which the directivity direction of the transmission beam is limited to a beam directed in the extending direction of the road.
12. The eleventh aspect of claim 11, wherein the transmitting antenna control unit changes the variable range from the first transmission range to the second transmission range when the road is permitted to travel by switching the light color of the traffic signal. Mobile communication system.
13. An in-vehicle mobile station that waits for information necessary for communication connection from a wireless control station while changing the directivity direction of the received beam.
    The receiving antenna forming the receiving beam and
    An in-vehicle mobile station including a receiving antenna control unit that changes a variable range of the directivity of the receiving beam according to the position of the in-vehicle mobile station.
14. A wireless control station that transmits information necessary for communication connection with an in-vehicle mobile station while changing the directivity direction of the transmission beam.
    The transmitting antenna forming the transmitting beam and
    A wireless control station including a transmission antenna control unit that changes a variable range of the directivity direction of the transmission beam according to the light color of a traffic signal installed on a road on which the vehicle-mounted mobile station moves.
15. It is a reception beam control method performed by an in-vehicle mobile station that waits for information necessary for communication connection from a wireless control station.
    The step of forming the received beam while changing the directivity,
    A method for controlling a reception beam, which includes a step of changing a variable range of the directivity of the reception beam according to the position of the vehicle-mounted mobile station.
16. It is a transmission beam control method performed by a wireless control station that transmits information necessary for communication connection with an in-vehicle mobile station.
    Steps to form a transmitting beam while changing the directivity,
    A method for controlling a transmission beam, which includes a step of changing a variable range of a directivity direction of the transmission beam according to a light color of a traffic signal installed on a road on which the vehicle-mounted mobile station moves.

Images