JP2021177605A - Base station, mobile communication system, and information generation method - Google Patents

Abstract

To provide a base station, a mobile communication system, and an information generation method that shorten a time for searching for the directivity of an antenna.SOLUTION: A base station BS that performs wireless communication between a plurality of mobile terminals with their directivity directed to each other includes a processing device that performs wireless communication by controlling an antenna whose directivity can be controlled. The processing device executes processing of updating a database in which the location information of a plurality of connection terminals connected to the own station by wireless communication is registered, transmission control processing of causing the own station and the plurality of connection terminals to send a signal including the time when a notification is received from a request terminal that requests a communication connection by wireless communication, generation processing of determining the position of the request terminal, and generating direction information indicating the direction from one side to the other between the request terminal and the base station on the basis of the position information and propagation time information of each signal generated by the request terminal that has received a plurality of signals transmitted from the own station and the plurality of connection terminals, and information transmission processing of sending the direction information to the request terminal.SELECTED DRAWING: Figure 12

Description

The present disclosure relates to base stations, mobile communication systems, and information generation methods.

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 base station or mobile terminal in the system performs beamforming in order to compensate for the attenuation of radio waves. The base station and the mobile terminal can improve the gain by directing the direction of the beam (directivity direction of the antenna) in a specific direction by beamforming.

Since the base station (mobile terminal) performs wireless communication with the directivity direction of the antenna directed toward the mobile terminal (base station), it is necessary to specify the directivity direction toward the mobile terminal (base station) side.
Therefore, the base station performs beam sweeping at a stage before starting wireless communication with the mobile terminal. Beam sweeping is a process of changing the directivity direction of the antenna, which makes it possible to search for an appropriate directivity direction with respect to the mobile terminal.

In beam sweeping, the base station sequentially transmits broadcast information by a plurality of beams having different directions. When the mobile terminal receives this broadcast information, it transmits the minimum information (preamble) as well as the identification information for identifying the direction of the beam used for transmitting the broadcast information to the base station.
The base station recognizes the existence of the mobile terminal by receiving the information transmitted from the mobile terminal, and identifies the direction of the beam used for transmitting the broadcast information based on the identification information from the mobile terminal. An appropriate pointing direction with respect to the mobile terminal can be specified (see, for example, Patent Document 1).
After that, a random access process is performed between the base station and the mobile terminal, and then a communication connection is made and wireless communication is started.

International Publication No. 2018/134995

When performing wireless communication using millimeter waves, it is necessary to direct the directivity of the antenna toward the base station even in the mobile terminal.
Therefore, the mobile terminal attempts to receive the broadcast information transmitted from the base station before starting wireless communication with the base station by millimeter waves. The mobile terminal changes the directivity direction of the antenna, searches for the arrival direction of the broadcast information from the base station, and specifies the directivity direction of the antenna facing the base station side. After that, the mobile terminal starts a procedure such as random access processing for starting wireless communication by millimeter wave.

Here, when searching for a base station, the mobile terminal may search in a direction in which the base station does not exist. Moreover, the base station also changes the direction of the beam that transmits the broadcast information, and both the base station and the mobile terminal change the directivity direction of the antenna. Therefore, the mobile terminal cannot receive the broadcast information unless the directivity directions of the antennas of the base station and the mobile terminal face each other. Therefore, it may take a relatively large amount of time for the mobile terminal to specify the directivity direction of the antenna facing the base station side, that is, the direction from the mobile terminal to the base station.
The time required to search for the direction from the mobile terminal to the base station puts pressure on the communication time between the mobile terminal and the base station, which causes a decrease in throughput.

As described above, in wireless communication having directivity such as wireless communication using millimeter waves, the throughput may decrease depending on the time required for searching the direction from the mobile terminal to the base station. Therefore, a measure for shortening the time required to search the direction from the mobile terminal to the base station is desired.

The present disclosure has been made in view of such circumstances, and an object of the present disclosure is to provide a technique capable of shortening the time required to search for a direction from a mobile terminal to a base station.

The base station according to the embodiment is a base station that performs wireless communication with a plurality of mobile terminals in directions of direction, and controls an antenna whose direction can be controlled and the antenna. The processing unit includes a processing unit that performs processing related to the wireless communication, and the processing unit updates a database in which location information of a plurality of connected terminals that communicate with the own station by the wireless communication among the plurality of mobile terminals is registered. When a notification is received from the requesting terminal requesting the communication connection by the wireless communication among the plurality of mobile terminals, the signal including the time transmitted from the own station and the plurality of connected terminals is transmitted to the own station and the plurality of connected terminals. Transmission control processing to be transmitted to the plurality of connected terminals, the position information, and propagation time information of each signal generated by the requesting terminal that has received the plurality of the signals transmitted from the own station and the plurality of connected terminals. Based on, the position of the requesting terminal is determined, and the generation process of generating the direction information indicating the direction from one to the other between the requesting terminal and the base station and the direction information are transmitted to the requesting terminal. Information transmission processing and execution.

Further, the mobile communication system according to another embodiment is a mobile communication system including a plurality of mobile terminals and a base station that performs wireless communication in which directions are directed to each other between the plurality of mobile terminals. The base station includes an antenna whose direction can be controlled and a processing unit that performs processing related to the wireless communication by controlling the antenna. The processing unit is one of the plurality of mobile terminals. The process of updating the database in which the location information of a plurality of connected terminals that communicate with the station by the wireless communication is registered, and the notification is received from the requesting terminal that requests the communication connection by the wireless communication among the plurality of mobile terminals. Then, the transmission control process for transmitting the signal including the time transmitted from the own station and the plurality of connected terminals to the own station and the plurality of connected terminals, the position information, and the own station and the plurality of connected terminals Based on the propagation time information of each signal generated by the requesting terminal that has received the plurality of transmitted signals, the position of the requesting terminal is determined, and one to the other between the requesting terminal and the base station. A generation process for generating direction information indicating a direction toward the direction and an information transmission process for transmitting the direction information to the request terminal are executed, and the plurality of mobile terminals have a terminal antenna whose direction can be controlled and a terminal antenna whose direction can be controlled. A terminal processing unit that performs processing related to the wireless communication by controlling the terminal antenna is provided, and the terminal processing unit controls the direction of the antenna and receives the direction information to obtain the direction information. Based on this, a directional control process for limiting the variable range of the directional direction of the antenna is executed.

Further, the information generation method according to another embodiment is an information generation method for generating direction information, which is executed by a base station that performs wireless communication in which directions are directed to each other with a plurality of mobile terminals. By the step of updating the database in which the position information of the plurality of connected terminals that communicate with the own station by the wireless communication among the plurality of mobile terminals is registered, and the wireless communication among the plurality of mobile terminals. When a notification is received from a request terminal requesting a communication connection, a step of causing the own station and the plurality of connected terminals to transmit a signal including a time transmitted from the own station and the plurality of connected terminals, the position information, and the above-mentioned location information. Based on the propagation time information of each signal generated by the requesting terminal that has received the plurality of the signals transmitted from the own station and the plurality of connecting terminals, the position of the requesting terminal is determined, and the requesting terminal and the requesting terminal and the requesting terminal It includes a step of generating direction information indicating a direction from one side to the other between the base stations, and a step of transmitting the direction information to the request terminal.

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

According to the present disclosure, the time required to search the directivity direction of the antenna can be shortened.

FIG. 1 is a plan view showing a mobile communication system according to an embodiment. FIG. 2 is a diagram for explaining wireless communication between terminals. FIG. 3 is a diagram showing an example of a location database in which location information of mobile terminals owned by a base station is registered. FIG. 4 is a sequence diagram showing an example of processing performed when a base station and a mobile terminal communicate with each other by millimeter wave communication. FIG. 5 is a sequence diagram showing an example of processing performed when a base station and a mobile terminal communicate with each other by millimeter wave communication. FIG. 6 is a diagram showing an example of propagation time information transmitted by the mobile terminal. FIG. 7 is a diagram showing the positional relationship between the base station and the mobile terminal. FIG. 8 is a diagram showing a positional relationship when a shield is interposed between the base station and the mobile terminal. FIG. 9 is a diagram showing a case where the first mobile terminal is surrounded by a building or the like and therefore cannot receive the second reference signal from the surrounding second mobile terminal. FIG. 10 is a diagram showing the positional relationship between the first mobile terminal and the second mobile terminal in FIG. FIG. 11 is a block diagram showing a configuration example of the mobile terminal of the present embodiment. FIG. 12 is a block diagram showing a configuration example of the base station of the present embodiment.

First, the contents of the embodiments will be listed and described.
[Outline of Embodiment]
(1) The base station according to the embodiment is a base station that performs wireless communication with a plurality of mobile terminals in directions of direction, and controls an antenna whose direction can be controlled and the antenna. This includes a processing unit that performs processing related to the wireless communication, and the processing unit registers the position information of a plurality of connected terminals that communicate with the own station by the wireless communication among the plurality of mobile terminals. When a notification is received from the process of updating the database and the requesting terminal requesting the communication connection by the wireless communication among the plurality of mobile terminals, a signal including the time transmitted from the own station and the plurality of connected terminals is transmitted. Transmission control processing to be transmitted to the own station and the plurality of connected terminals, the position information, and propagation of each signal generated by the requesting terminal that has received the plurality of the signals transmitted from the own station and the plurality of connected terminals. A generation process for positioning the position of the requesting terminal based on the time information and generating direction information indicating a direction from one to the other between the requesting terminal and the base station, and the request for the direction information. Executes the information transmission process to be transmitted to the terminal.

According to the base station having the above configuration, the position of the requesting terminal is obtained by positioning based on the position information and the propagation time information, the direction information from the requesting terminal to the base station is generated, and the direction information is given to the requesting terminal.
Therefore, when the requesting terminal requests a communication connection with the base station by directional wireless communication, the requesting terminal controls the pointing direction of the antenna based on the direction information, so that the requesting terminal moves from the requesting terminal to the base station. The time required to search for the facing direction can be shortened.

(2) In the base station, the signal includes a first signal transmitted by the base station and a second signal transmitted by the plurality of connecting terminals, and in the transmission control process, when the notification is received, the signal is received. The first signal may be transmitted to the plurality of mobile terminals that transmit the second signal in response to the reception of the first signal.
In this case, the processing unit can transmit the second signal to a plurality of connected terminals by transmitting the first signal.

(3) In the base station, the processing unit makes a communication connection with the requesting terminal by omnidirectional wireless communication, and receives the notification and the propagation time information by the omnidirectional wireless communication. It may be configured to perform communication processing.
In this case, the communication process can be executed by wireless communication other than wireless communication performed with the directivity directions directed to each other.

(4) Further, in the base station, the processing unit executes a determination process of determining whether or not the position of the request terminal is within the area where the wireless communication is possible, and in the information transmission process, the request When it is determined that the position of the terminal is outside the area, the transmission of the direction information may be stopped.
In this case, it is possible to suppress unnecessary transmission of direction information to a requesting terminal that cannot be connected by wireless communication in which the directivity directions are directed to each other.

(5) Further, in the base station, the area may be defined based on the position information of each of the plurality of connected terminals.
In this case, the area can be defined accurately.

(6) Further, the mobile communication system according to another embodiment is a mobile communication including a plurality of mobile terminals and a base station that performs wireless communication in which directions are directed to each other between the plurality of mobile terminals. In the system, the base station includes an antenna whose direction can be controlled and a processing unit that performs processing related to the wireless communication by controlling the antenna, and the processing unit is the plurality of mobile terminals. From the process of updating the database in which the location information of the plurality of connected terminals that communicate with the own station by the wireless communication is registered, and from the requesting terminal that requests the communication connection by the wireless communication among the plurality of mobile terminals. When the notification is received, the transmission control process for causing the own station and the plurality of connected terminals to transmit a signal including the time transmitted from the own station and the plurality of connected terminals, the position information, the own station and the plurality of connected terminals. The position of the requesting terminal is determined based on the propagation time information of each signal generated by the requesting terminal that has received the plurality of the signals transmitted from the connecting terminal, and the position of the requesting terminal is determined between the requesting terminal and the base station. A generation process for generating direction information indicating a direction from one to the other and an information transmission process for transmitting the direction information to the request terminal are executed, and the plurality of mobile terminals are terminals whose direction can be controlled. The terminal processing unit includes an antenna and a terminal processing unit that performs processing related to the wireless communication by controlling the terminal antenna. The terminal processing unit controls the direction of the antenna and receives the direction information. A directional control process that limits the variable range of the directional direction of the antenna is executed based on the directional information.

According to the mobile communication system having the above configuration, the time required to search the direction from the requesting terminal to the base station is shortened by controlling so as to limit the variable range of the directivity direction of the antenna based on the direction information. be able to.

(7) In the mobile communication system, the signal includes a first signal transmitted by the base station and a second signal transmitted by the plurality of connected terminals, and the terminal processing unit uses the first signal. Upon receipt, it may be configured to execute an inter-terminal transmission control process for transmitting the second signal by inter-terminal wireless communication.
In this case, the distance between the plurality of connecting terminals and the requesting terminal can be measured by the second signal.

(8) In the mobile communication system, when the terminal processing unit receives the signal after transmitting the notification, the terminal processing unit generates propagation time information corresponding to the received signal and transmits the propagation time information to the base station. It may be configured to perform processing.
In this case, the plurality of mobile terminals can transmit the propagation time information to the base station when the notification is transmitted as the request terminal.

(9) Further, the information generation method according to another embodiment is information for generating direction information executed by a base station that performs wireless communication in which directions are directed to each other with a plurality of mobile terminals. The generation method includes a step of updating a database in which location information of a plurality of connected terminals that communicate with the own station by the wireless communication among the plurality of mobile terminals is registered, and the step of updating the database among the plurality of mobile terminals. When a notification is received from a request terminal requesting a communication connection by wireless communication, a step of causing the own station and the plurality of connected terminals to transmit a signal including a time transmitted from the own station and the plurality of connected terminals, and the position. The position of the request terminal is determined based on the information and the propagation time information of each signal generated by the request terminal that has received the plurality of signals transmitted from the own station and the plurality of connected terminals. It includes a step of generating direction information indicating a direction from one side to the other between the request terminal and the base station, and a step of transmitting the direction information to the request terminal.

[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 mobile communication system according to an embodiment.
In FIG. 1, the mobile communication system 1 includes a base station BS and a plurality of mobile terminals TE1 to TE8. In the following description, the mobile terminals TE1 to TE8 may be collectively referred to as a mobile terminal TE.

The base station BS may also be referred to as a remote unit, a remote radio head, or the like.
The base station BS has a function of performing wireless communication with a plurality of mobile terminals TE. The base station BS, for example, performs wireless communication based on the 5th generation mobile communication system. The base station BS has a function of performing beamforming. The base station BS has an antenna whose directivity can be controlled, and has a function of controlling the directivity of the antenna and communicating the direction of the transmission / reception beam toward the communication destination.
The base station BS can perform wireless communication by combining wireless communication using a signal in a frequency band of 6 GHz or less and wireless communication using a signal in a millimeter wave frequency band higher than 6 GHz.

Wireless communication using a signal in a frequency band of 6 GHz or less is wireless communication using a frequency band called a sub 6 GHz band (Sub-6), which is a frequency band defined in a fifth generation mobile communication system.
In the following, wireless communication using a signal in a frequency band of 6 GHz or less may be referred to as sub 6 GHz communication, and wireless communication using a signal in a millimeter wave frequency band higher than 6 GHz may be referred to as millimeter wave communication.

Since the frequency band used for millimeter wave communication is higher than the frequency band used for sub 6 GHz communication, the coverage area of sub 6 GHz communication is generally wider than that of millimeter wave communication.
Therefore, the communication cell to which the base station BS can provide the service to the mobile terminal TE depends on the sub 6 GHz communication.

Cell C of the base station BS shown in FIG. 1 is an area where wireless communication is possible by sub 6 GHz communication. The base station BS is capable of sub 6 GHz communication with the mobile terminal TE in the cell C.
Further, a millimeter wave communication area M, which is an area where millimeter wave communication is possible, is formed in the cell C. The base station BS is capable of millimeter wave communication with the mobile terminal TE in the millimeter wave communication area M. That is, the millimeter wave communication area M is an area where communication connection by millimeter wave communication is possible between the base station BS and the mobile terminal TE.

The mobile terminal TE includes in-vehicle terminals mounted on vehicles such as automobiles and railways, as well as mobile phones, smartphones, tablet terminals, laptop computers, and the like possessed by pedestrians and the like.
The mobile terminal TE performs wireless communication with the base station BS in accordance with the 5th generation mobile communication system. Therefore, the mobile terminal TE also has a function of performing beamforming. The mobile terminal TE has an antenna capable of controlling the directivity direction, and has a function of controlling the directivity direction of the antenna and communicating the direction of the transmission / reception beam toward the communication destination.

The mobile terminal TE can also perform wireless communication by sub 6 GHz communication and millimeter wave communication.
The mobile terminal TE does not control the directivity direction of the antenna for sub 6 GHz communication, and performs wireless communication in an omnidirectional manner. For millimeter-wave communication, the mobile terminal TE controls the directivity direction of the antenna so that it faces the base station BS side, and performs wireless communication.
That is, in the mobile terminal TE, the sub 6 GHz communication is omnidirectional wireless communication, and the millimeter wave communication is directional wireless communication in which wireless communication is performed with the directions directed to each other.

The plurality of mobile terminals TE in the cell C include a mobile terminal that communicates with the base station BS by sub 6 GHz communication and a mobile terminal TE that communicates with the base station BS by sub 6 GHz communication and millimeter wave communication.
In FIG. 1, the mobile terminals TE1, TE4, TE6, and TE8 are located in the cell C but outside the millimeter wave communication area M. Therefore, the mobile terminals TE1, TE4, TE6, and TE8 communicate with the base station BS by sub 6 GHz communication, but do not communicate with the base station BS by millimeter wave communication.
In FIG. 1, the mobile terminals TE2, TE3, TE5, and TE7 are located in the millimeter wave communication area. The mobile terminals TE2, TE3, TE5, and TE7 communicate with the base station BS by sub 6 GHz communication and millimeter wave communication.

In the following description, the mobile terminal TE which is connected to the base station BS by sub 6 GHz communication but whose communication connection by millimeter wave communication is not established is also referred to as an unconnected terminal TE-1.
Further, the mobile terminal TE that communicates and connects with the base station BS by sub 6 GHz communication and millimeter wave communication is also referred to as a connection terminal TE-2 in the following description.
Therefore, the mobile terminals TE1, TE4, TE6, and TE8 are unconnected terminals TE-1, and the mobile terminals TE2, TE3, TE5, and TE7 are connected terminals TE-2.

The communication connection refers to a state in which data such as a payload can be transmitted and received between the base station BS and the mobile terminal TE, or between the mobile terminals TE.
Further, when the base station BS and the mobile terminal TE communicate with each other by millimeter wave communication or sub 6 GHz communication, the mobile terminal TE synchronizes the internal time of the own terminal TE with the internal time of the base station BS. Therefore, the internal time between the mobile terminals TE that are connected to the base station BS by communication is also synchronized.

Further, the mobile terminal TE may have a function of performing wireless communication conforming to the 4th generation mobile communication system. The cell C is included in the cell formed by the base station of the 4th generation mobile communication system, and can be transmitted and received by both communication systems.

Further, the plurality of mobile terminals TE have a function of mutually performing wireless communication between terminals.
FIG. 2 is a diagram for explaining wireless communication between terminals.
As shown in FIG. 2, the mobile terminal TE has a function (access link) of communicating with the base station BS by sub 6 GHz communication or millimeter wave communication, and also directly communicates with another mobile terminal TE. It has a function (side link).
The mobile terminal TE mutually performs wireless communication between terminals by a side link. Sidelinks are omnidirectional wireless communications. The side link uses a radio resource different from that of the access link, or shares the same radio resource in a time-division manner. Therefore, the mobile terminal TE can establish a side link with another mobile terminal TE while establishing an access link with the base station BS.

The base station BS has a function of managing the position of the mobile terminal TE in the cell C.
FIG. 3 is a diagram showing an example of a position database in which the position information of the mobile terminal TE of the base station BS is registered.
The location database 2 shown in FIG. 3 is stored in a storage device included in the base station BS.
As shown in FIG. 3, the position database 2 has a column 2a for registering an ID for identifying each mobile terminal TE, a column 2b for registering position information (Position) of each mobile terminal TE, and a millimeter wave. It has a column 2c for registering information (mmWave) indicating whether or not the communication is connected by communication, and a column 2d for registering information (Sub6) indicating whether or not the communication is connected by sub 6 GHz communication. ..
The position information of each mobile terminal TE is registered in the position database 2 in association with the ID of the mobile terminal TE. Each position information registered in the position database 2 is stored and updated by the base station BS.

For example, the mobile terminal TE whose ID is "TE2" corresponds to the mobile terminal TE2 in FIG. Therefore, the position information "(X2, Y2)" indicating the position of the mobile terminal TE2 is registered in the portion of the column 2b whose ID corresponds to "TE2". The position information is, for example, a coordinate value indicating a position in the area where the cell C is formed.
Further, the mobile terminal TE2 is communicated with the base station BS by both sub 6 GHz communication and millimeter wave communication. Therefore, "connection" is registered in each of the parts of columns 2c and 2d whose ID corresponds to "TE2". These pieces of information registered in columns 2c and 2d indicate that the mobile terminal TE2 is the connecting terminal TE-2.

The mobile terminal TE whose ID is "TE1" corresponds to the mobile terminal TE1 in FIG. The mobile terminal TE1 communicates with the base station BS by sub 6 GHz communication, and does not communicate with the base station BS by millimeter wave communication. Therefore, "not connected" is registered in the portion of the column 2c whose ID corresponds to "TE1", and "connected" is registered in the portion of the column 2d whose ID corresponds to "TE1". These information registered in these columns 2c and 2d indicate that the mobile terminal TE1 is an unconnected terminal TE-1.
Further, in the column 2b for registering the position information, the position information is not registered and is blank.
Further, the mobile terminals TE having IDs of "TE3", "TE4", "TE5", "TE6", "TE7", and "TE8" are mobile terminals TE3, TE4, TE5, TE6, TE7, in FIG. It corresponds to TE8.

In addition, the location information of the own station BS is also registered in the location database 2. The ID of the own station BS is "BS", and the position information of the own station BS is registered in the portion where the ID corresponds to "BS" in the column 2b.

When the base station BS acquires the position information of each mobile terminal TE, the base station BS updates the contents of the position database 2.
When the mobile terminal TE has a GPS receiver, the location information is notified from the mobile terminal TE.

In the position database 2 in FIG. 3, the position information of the mobile terminals TE1, TE4, TE6, and TE8, which are the unconnected terminals TE-1, is not registered. However, if these mobile terminals TE1, TE4, TE6, and TE8 have a GPS receiver, the position information obtained by the GPS receiver can be transmitted to the base station BS by sub 6 GHz communication.
In this case, the base station BS can register the position information of the mobile terminals TE1, TE4, TE6, and TE8 in the position database 2.
Further, when the mobile terminal TE having no GPS receiver is the connection terminal TE-2, the position information of the mobile terminal TE is not registered in the position database 2.

In this way, the base station BS registers and manages the position information of the mobile terminal TE located in the cell C in the position database 2.

In this embodiment, at least the mobile terminal TE6 does not have a GPS receiver.
Further, the mobile terminals TE2, TE3, TE5, and TE7, which are the connection terminals TE-2, may be fixedly installed at known positions. In this case, the mobile terminals TE2, TE3, TE5, and TE7 do not need to be equipped with a GPS receiver.

[Communication connection processing]
4 and 5 are sequence diagrams showing an example of processing performed when the base station BS and the mobile terminal TE communicate with each other by millimeter wave communication.
A in FIG. 4 is connected to A in FIG. 5, B in FIG. 4 is connected to B in FIG. 5, C in FIG. 5 is connected to C in FIG. 4, and D in FIG. 5 is connected to FIG. It is connected to D in FIG. 4, and E in FIG. 4 is connected to E in FIG.
4 and 5 show, for example, a case where the mobile terminal TE6 (see FIG. 1), which is the unconnected terminal TE-1 shown in FIG. 1, moves from outside the millimeter-wave communication area M to inside the area.

In FIG. 4, the base station BS manages the position information of each mobile terminal TE (step S1). As a result, as shown in FIG. 3, in the position database 2 of the base station BS, in addition to the position information of the own station BS, the positions of the mobile terminals TE2, TE3, TE5, and TE7, which are the connection terminals TE-2, are stored. Information is registered or updated.

The mobile terminal TE6 first determines whether or not millimeter-wave communication is required between the own terminal TE6 and the base station BS (step S2).
The mobile terminal TE6 may determine that millimeter-wave communication is always required while it is located in cell C of the base station BS, for example. Further, the mobile terminal TE6 may determine that millimeter wave communication is necessary based on the operation of the owner of the mobile terminal TE6, information given by the base station BS by sub 6 GHz communication, etc. It may be determined whether or not millimeter wave communication is necessary based on the information from the device of.
The mobile terminal TE6 repeats step S2 until it determines that millimeter-wave communication is necessary.
Therefore, when it is determined that millimeter-wave communication is always required while located in cell C of the base station BS, the mobile terminal TE6 needs millimeter-wave communication if it enters the cell C from outside the cell C. judge.

The mobile terminal TE6, which has determined that millimeter-wave communication is necessary, transmits a request notification requesting a communication connection by millimeter-wave communication to the base station BS (step S3). The mobile terminal TE6 transmits a request notification omnidirectionally by sub 6 GHz communication.
That is, the mobile terminal TE6 is a request terminal that requests the base station BS to make a communication connection by millimeter wave communication.

The base station BS that has received the request notification in step S4 transmits the first reference signal to each mobile terminal TE by sub 6 GHz communication.
The first reference signal includes the ID of the base station BS and the transmission time when the first reference signal is transmitted from the base station BS.

The connection terminal TE-2 (mobile terminals TE2, TE3, TE5, TE7) that received the first reference signal in step S6 transmits the second reference signal by wireless communication (side link) between terminals (step S7).
The second reference signal includes the ID of the mobile terminal TE indicating the transmission source and the transmission time when the second reference signal is transmitted from the mobile terminal TE of the transmission source.
The second reference signal includes the ID of the base station BS included in the first reference signal that triggered the transmission of the second reference signal and the time when the first reference signal is transmitted from the base station BS. The transmission time and may be included.

In this way, when the base station BS receives the request notification from the mobile terminal TE6 which is the request terminal, the base station BS transmits the first reference signal and causes the connection terminal TE-2 to transmit the second reference signal.
The base station BS can transmit the second reference signal from the connection terminal TE-2 by transmitting the first reference signal.
Further, since the connecting terminal TE-2 transmits the second reference signal by the side link, when the mobile terminal TE6 described later is positioned, the second reference signal is used between the plurality of connecting terminals and the requesting terminal. The distance can be measured.

After transmitting the request notification in step S3, the mobile terminal TE6 waits for a predetermined time to elapse (step S8), during which the first reference signal from the base station BS and the second reference signal from the connection terminal TE-2. Wait for a reference signal.
After a predetermined time has elapsed from the transmission of the request notification, the mobile terminal TE6 determines whether or not the reference signal has been received (step S9).
If it is determined in step S9 that no reference signal has been received, the mobile terminal TE6 returns to step S2.
In this case, since the mobile terminal TE6 cannot obtain the information necessary for generating the direction information described later, the mobile terminal TE6 returns to step S2 again and repeats the process.
If it is determined in step S9 that the reference signal has been received, the mobile terminal TE6 transmits the propagation time information corresponding to the received signal to the base station BS by sub 6 GHz communication (step S10).

FIG. 6 is a diagram showing an example of propagation time information transmitted by the mobile terminal TE6.
When the mobile terminal TE6 receives the reference signal, it generates propagation time information corresponding to the received reference signal.
The propagation time information includes the corresponding source ID and the transmission time and reception time of the reference signal received by the mobile terminal TE6. The propagation time information is information indicating the propagation time of the reference signal received by the mobile terminal TE6.

In FIG. 6, the propagation time information in which the source ID is “BS” is the transmission time and reception time of the first reference signal transmitted by the base station BS.
Further, the propagation time information having the transmission source ID "TE3" is the transmission time and the reception time of the second reference signal transmitted by the mobile terminal TE3. The propagation time information in which the source ID is "TE7" is the transmission time and reception time of the second reference signal transmitted by the mobile terminal TE7.
The propagation time information with the source ID "TE2" is the transmission time and the reception time of the second reference signal transmitted by the mobile terminal TE2, and the propagation time information with the source ID "TE5" is the mobile terminal TE5. Is the transmission time and reception time of the second reference signal transmitted by.

The first reference signal from the base station BS includes the ID of the base station BS and the transmission time of the first reference signal. The mobile terminal TE6 stores the reception time when the first reference signal is received.
Further, the second reference signal from the mobile terminals TE2, TE3, TE5, and TE7 also includes the ID of the transmission source and the transmission time of the second reference signal. The mobile terminal TE6 stores the reception time when each second reference signal is received.
Therefore, the mobile terminal TE6 can generate propagation time information based on each received reference signal.

When the mobile terminal TE6 receives all the first reference signal from the base station BS and the second reference signal from the mobile terminals TE2, TE3, TE5, and TE7, the mobile terminal TE6 has 5 as shown in FIG. Propagation time information is generated and transmitted for each of the two reference signals.

Further, for example, when the mobile terminal TE6 receives the first reference signal from the base station BS and the second reference signal from the mobile terminals TE3 and TE7, the mobile terminal TE6 has the propagation time information corresponding to the first reference signal. , Propagation time information corresponding to the second reference signal of the mobile terminal TE3 and propagation time information corresponding to the mobile terminal TE7 are generated and transmitted.

Returning to FIG. 4, when the mobile terminal TE6 transmits the propagation time information (step S10) and the base station BS receives the propagation time information from the mobile terminal TE6 (step S11), the base station BS receives the corresponding reference signal. Determines whether or not has received three or more propagation time information different from each other (step S12).
When it is determined that three or more propagation time information has been received, the base station BS proceeds to step S14 and performs positioning calculation for obtaining the position of the mobile terminal TE6 based on the propagation time information (step S14).
On the other hand, when one propagation time information or two propagation time information whose corresponding reference signals are different from each other is received, the base station BS proceeds to step S30. The processing after step S30 will be described later.

In step S14, the base station BS positions the mobile terminal TE6 based on the propagation time information and the position information registered in the position database 2.
The base station BS obtains the propagation time of the reference signal from the source to the mobile terminal TE6 from the transmission time and the reception time included in the propagation time information.
The base station BS obtains the propagation time of the reference signal for each of the received propagation time information.
The propagation time of each reference signal indicates the distance from the source of each reference signal to the mobile terminal TE6. Further, in the location database 2, the location information of the own station BS and the location information (location information of the transmission source) of each of the connection terminals TE-2 are registered.
Therefore, the base station BS moves by three-point positioning based on the positions of the sources of at least three reference signals by using the propagation times of at least three reference signals and the position information of the sources of at least three reference signals. The position of the terminal TE6 can be obtained.

FIG. 7 is a diagram showing the positional relationship between the base station BS and the mobile terminal TE.
In FIG. 7, the base station BS has the propagation time of the first reference signal transmitted by the base station BS and the propagation time of each of the second reference signals transmitted by the mobile terminal TE3 and the mobile terminal TE7 (connection terminal TE-2). Will be used to describe the case where the mobile terminal TE6 (unconnected terminal TE-1), which is the requesting terminal, is positioned.

In FIG. 7, the mobile terminal TE6 is located in the millimeter wave communication area M by moving from outside the millimeter wave communication area M.
The base station BS transmits a first reference signal in response to a request notification from the mobile terminal TE6.
The mobile terminal TE3 and the mobile terminal TE7 that have received the first reference signal transmit the second reference signal.
The mobile terminal TE6 receives the first reference signal from the base station BS and also receives the second reference signal from the mobile terminal TE3 and the mobile terminal TE7.
As a result, the mobile terminal TE6 has the propagation time information corresponding to the first reference signal, the propagation time information corresponding to the second reference signal from the mobile terminal TE3, and the propagation time corresponding to the second reference signal from the mobile terminal TE7. Information is transmitted to the base station BS.

The base station BS obtains the propagation time of the first reference signal transmitted by the base station BS and the propagation time of each of the second reference signals transmitted by the mobile terminal TE3 and the mobile terminal TE7 from the three received propagation time information. be able to.

Further, the base station BS grasps the positions of the mobile terminal TE3 and the mobile terminal TE7 from the position database 2. The base station BS also knows the position of its own station BS.
Therefore, the base station BS can determine the position of the mobile terminal TE6 by three-point positioning based on the position of the base station BS, the position of the mobile terminal TE3, and the position of the mobile terminal TE7.
The base station BS obtains the position of the mobile terminal TE6 as a coordinate value indicating a position in the area where the cell C is formed.

FIG. 7 shows a case where the position of the mobile terminal TE6 is obtained by three-point positioning based on the position of the base station BS, the position of the mobile terminal TE3, and the position of the mobile terminal TE7. When the propagation time information of 2 (mobile terminal TE2, mobile terminal TE5) is received, positioning may be performed using the positions of these connection terminals TE-2 as well.

When the base station BS of the present embodiment receives the propagation time information corresponding to the first reference signal, the position of the base station BS is prioritized and used for positioning.
Further, the base station BS compares the propagation time of each second reference signal, and preferentially uses the position of the mobile terminal TE, which is the source of the reference signal having a small propagation time, for positioning.
The smaller the propagation time, the closer the mobile terminal TE, which is the source of the second reference signal, to the mobile terminal TE6, there are no obstacles in the propagation path, and the propagation time is the actual distance and accuracy. It can be considered that they correspond well. Therefore, if the position of the mobile terminal TE, which is the source of the reference signal having a short propagation time, is preferentially used for positioning, the position of the mobile terminal TE6 can be accurately obtained.
The base station BS may perform three-point positioning using only the position of the connection terminal TE-2.

When the positioning calculation of the mobile terminal TE6 is performed in step S14 in FIG. 4, the base station BS proceeds to step S15 in FIG. 5, and the position of the mobile terminal TE6 obtained by the positioning calculation is within the millimeter wave communication area M. Whether or not it is determined (step S15).
The base station BS defines the range of the millimeter wave communication area M based on the position information of each of the connection terminals TE-2 registered in the position database 2.
For example, the periphery of the base station BS is divided by a constant azimuth angle to set a plurality of azimuth angle areas, and among the connection terminal TE-2 existing in each azimuth angle area, the connection terminal TE-, which is the farthest from the base station BS. 2 is defined as the outer edge of the millimeter wave communication area M, and the millimeter wave communication area M is defined.
Thereby, the millimeter wave communication area M can be defined with high accuracy.

When determining that the position of the mobile terminal TE6 is outside the millimeter wave communication area M, the base station BS proceeds to step S25 and issues an out-of-area notification indicating that the position of the mobile terminal TE6 is outside the millimeter wave communication area M. , Is transmitted to the mobile terminal TE6 by sub 6 GHz communication (step S25).
After that, the base station BS returns to C in FIG. 4 and waits for the transmission of the request notification from the mobile terminal TE again.
In this case, the base station BS determines that the mobile terminal TE6 cannot be connected to the mobile terminal TE6 by millimeter wave communication because the position of the mobile terminal TE6 is outside the millimeter wave communication area M, and stops the generation and transmission of the direction information. Wait for the next request notification.
Therefore, in this case, the base station BS can suppress the useless generation and transmission of the direction information described below to the mobile terminal TE which cannot be connected by the millimeter wave communication.

When determining that the position of the mobile terminal TE6 is within the millimeter wave communication area M, the base station BS generates direction information (step S16) and transmits the direction information to the mobile terminal TE6 which is the request terminal (step S17).
The direction information is information indicating the direction from the mobile terminal TE6 toward the base station BS, and includes an azimuth angle and an elevation angle.
The azimuth is represented by, for example, the central angle on the horizontal plane when the north direction is used as a reference and the clockwise direction is positive. The elevation angle is represented by, for example, an angle with respect to the horizontal direction on a vertical plane.

The base station BS obtains the azimuth angle based on the position of the mobile terminal TE6 and the position of the own station BS. Further, the base station BS obtains an elevation angle based on the position of the mobile terminal TE6, the position of the own station BS, and the height of the antenna of the own station BS from the ground.
The value of the height of the antenna of the own station BS from the ground is stored in advance in the storage device of the base station BS as information necessary for obtaining the elevation angle.
Further, the height value of the mobile terminal TE6 from the ground may also be stored in the storage device of the base station BS. In this case, the elevation angle can be obtained more accurately by using the height value of the mobile terminal TE6 from the ground when obtaining the elevation angle. As the height value of the mobile terminal TE6 from the ground, the average value of the heights when a pedestrian or a occupant of a vehicle carries the mobile terminal TE can be used.

The base station BS transmits the direction information obtained as described above to the mobile terminal TE6 by sub 6 GHz communication.

On the other hand, when the mobile terminal TE6 transmits the propagation time information in step S10 in FIG. 4, it proceeds to step S18 in FIG. 5 and waits for a predetermined time to elapse (step S18). When a predetermined time has elapsed from the transmission of the propagation time information, the mobile terminal TE6 determines whether or not the out-of-area notification from the base station BS has been received during this predetermined time (step S19).
When the out-of-area notification is received, the mobile terminal TE6 returns to D in FIG. 4, and returns to step S2 in FIG. Therefore, the mobile terminal TE6 again determines whether or not millimeter wave communication is necessary.

If it is determined that the out-of-area notification has not been received, the mobile terminal TE6 proceeds to step S20 and determines whether or not the direction information has been received within the predetermined time (step S20).
When it is determined that the direction information is being received (step S20), the mobile terminal TE6 changes the directivity direction of the antenna and attempts to receive the broadcast information transmitted from the base station BS by millimeter wave communication. As a result, the mobile terminal TE6 searches for the direction of arrival of the broadcast information from the base station BS (step S21).

At this time, the mobile terminal TE6 limits the variable range of the directional direction of the antenna to the vicinity of the azimuth angle and the elevation angle indicated by the directional information in order to search for the base station BS.
The mobile terminal TE6 includes an orientation sensor for identifying the orientation. Therefore, the mobile terminal TE6 can specify the orientation regardless of the orientation and posture of the own terminal TE6. Therefore, the mobile terminal TE6 can control the directivity direction of the antenna according to the direction information regardless of the direction and orientation of the own terminal TE6.
The mobile terminal TE6 changes the directivity direction of the antenna within a range of 45 degrees before and after the azimuth angle indicated by the direction information, for example. Further, the mobile terminal TE6 changes the directivity direction of the antenna within a range of 15 degrees before and after the elevation angle indicated by the direction information.

The broadcast information from the base station BS is transmitted by beam sweeping performed by the base station BS.
The beam sweeping is a process in which the base station BS sequentially transmits broadcast information by a plurality of beams having different directions. The base station BS transmits broadcast information by millimeter wave communication in order to obtain an appropriate directivity direction of the antenna facing the mobile terminal TE.

Normally, when the mobile terminal TE attempts a communication connection with the base station BS by millimeter wave communication, the mobile terminal TE covers a wide range without limiting the variable range of the direction of the antenna in order to search for the base station BS. It is changed and attempts to receive the broadcast information transmitted from the base station BS by beam sweeping.
When the mobile terminal TE receives the broadcast information from the base station BS, the mobile terminal TE can obtain an appropriate antenna directivity toward the base station BS depending on the directivity direction of the antenna when the broadcast information is received.

Here, as described above, the mobile terminal TE6 of the present embodiment limits the variable range of the directional direction of the antenna to the vicinity of the azimuth angle and the elevation angle indicated by the directional information in order to search for the base station BS.
That is, the mobile terminal TE6 can search the base station BS without changing the directivity direction of the antenna in a wide range by being given the direction information.

The mobile terminal TE6 changes the directivity direction of the antenna in a narrower range based on the direction information.
As a result, the mobile terminal TE6 can efficiently search for the base station BS without directing the antenna in a direction in which the base station BS clearly does not exist, and can promptly receive the broadcast information.
As described above, since the mobile terminal TE6 of the present embodiment controls the directivity direction of the antenna based on the direction information, the time required to search the direction from the mobile terminal TE6 toward the base station BS can be shortened. ..

If it is determined in step S20 that the direction information has not been received, the mobile terminal TE6 returns to D in FIG. 4 and returns to step S2 in FIG. Therefore, the mobile terminal TE6 again determines whether or not millimeter wave communication is necessary.

If the direction information is not received within the predetermined time, it is possible that the direction information could not be received for some reason. Therefore, if the mobile terminal TE6 has not received the direction information within the predetermined time, the mobile terminal TE6 returns to step S2 in FIG. 4 again.
The predetermined time in step S18 is set to be longer than the time required for the base station BS to transmit the direction information after receiving the propagation time information.

As shown in FIG. 5, when the directivity direction of the antenna is changed in step S21 and the mobile terminal TE6 receives the broadcast information by millimeter wave communication from the base station BS in step S22, the mobile terminal TE6 performs a random access preamble. Send to the base station BS. As a result, the random access process is started between the base station BS and the mobile terminal TE6.
In the random access process, the base station BS and the mobile terminal TE6 exchange information necessary for connection by millimeter wave communication.
A communication connection by millimeter wave communication is established between the base station BS and the mobile terminal TE6 that have completed the random access process.

The mobile terminal TE6, which communicates with the base station BS by millimeter wave communication, repeatedly determines whether or not the millimeter wave communication with the base station BS is disconnected. If it is determined that the millimeter-wave communication with the base station BS has been disconnected, the mobile terminal TE6 executes step S2 in FIG. Therefore, when the millimeter-wave communication with the base station BS is disconnected, the mobile terminal TE6 again determines whether or not the millimeter-wave communication is necessary.
Further, the base station BS also repeatedly determines whether or not the millimeter-wave communication with the mobile terminal TE6 is disconnected, similarly to the mobile terminal TE6. When it is determined that the millimeter-wave communication with the mobile terminal TE6 is disconnected, the base station BS waits for the transmission of the request notification from the mobile terminal TE (step S3 in FIG. 4).

In this way, when the millimeter-wave communication with the base station BS is disconnected, the mobile terminal TE6 again determines whether or not the millimeter-wave communication is necessary, and the base station BS notifies the request from the mobile terminal TE. Wait for the transmission.

Therefore, for example, as shown in FIG. 8, when a shield is interposed between the base station BS and the mobile terminal TE6, which are connected to each other by millimeter wave communication, and the communication connection by millimeter wave communication is disconnected. Since the mobile terminal TE6 is still located in the cell C, it is determined that millimeter wave communication is necessary (step S2 in FIG. 4), and a request notification is transmitted to the base station BS (step in FIG. 4). S3).
Further, when the base station BS receives the request notification from the mobile terminal TE6 (step S4 in FIG. 4), the base station BS executes the above-mentioned process again and transmits the direction information to the mobile terminal TE6 (in FIG. 5). , Step S17).

Therefore, in the millimeter-wave communication area M, after the communication connection by millimeter-wave communication is disconnected between the base station BS and the mobile terminal TE for some reason, the mobile terminal TE is given the direction information given by the base station BS. By using the above, it is possible to shorten the time for searching the direction from the mobile terminal TE to the base station BS.
Therefore, after that, if the mobile terminal TE6 moves and the communication connection by the millimeter wave communication becomes possible, the communication connection by the millimeter wave communication can be promptly performed.

If it is determined in step S12 in FIG. 4 that the corresponding reference signals have not received three or more different propagation time information, the base station BS proceeds to step S30.
Assuming that three or more propagation time information is not received, that is, one or two propagation time information is received, for example, as shown in FIG. 9, the mobile terminal TE6 is surrounded by a building or the like. Therefore, it is conceivable that the environment is such that the second reference signal from the surrounding connection terminal TE-2 cannot be received.
In FIG. 9, the mobile terminal TE6 is capable of wireless communication between terminals only with the mobile terminal TE3 which is the connection terminal TE-2, and is capable of wireless communication between terminals with other connection terminals TE-2 (mobile terminals TE2, TE5, TE7). Since there is a building between them, wireless waves are blocked and wireless communication between terminals cannot be performed. Therefore, the second reference signal from the mobile terminals TE2, TE5, and TE7 does not reach the mobile terminal TE6.

In the following description, in the case shown in FIG. 9, the mobile terminal TE6, which is the unconnected terminal TE-1 and the requesting terminal, transmits a request notification to the base station BS, and the first reference signal from the base station BS and the first reference signal. The case where the mobile terminal TE6 receives the second reference signal from the mobile terminal TE3 which is the connection terminal TE-2 will be described.

In this case, the mobile terminal TE6 transmits the propagation time information corresponding to the first reference signal and the propagation time information corresponding to the second reference signal from the mobile terminal TE3 to the base station BS.
Therefore, the base station BS receives the two propagation time information.
Therefore, in step S12 in FIG. 4, the base station BS determines that three or more propagation time information has not been received, and proceeds to step S30.

Next, the base station BS determines whether or not the received propagation time information includes the propagation time information corresponding to the second reference signal (step S30).
When it is determined that the received propagation time information does not include the propagation time information corresponding to the second reference signal, the base station BS returns to the front of step S4 and again notifies the request from the mobile terminal TE. Wait for the transmission. In this case, if there is no propagation time information corresponding to the second reference signal, the subsequent processing cannot be performed.

When it is determined that the received propagation time information includes the propagation time information corresponding to the second reference signal, the base station BS determines that the propagation time information corresponding to the second reference signal is included in the mobile terminal. It is determined whether or not TE6 is located in the millimeter wave communication area M (step S31).

Here, the base station BS corresponds to the propagation time information (hereinafter, also referred to as the first propagation time information) corresponding to the first reference signal transmitted by the base station BS and the second reference signal transmitted by the mobile terminal TE3. The propagation time information (hereinafter, also referred to as the second propagation time information) is received. Therefore, the base station BS determines whether or not the mobile terminal TE6 is located in the millimeter wave communication area M based on the second propagation time information (step S31).

In this case, the base station BS cannot determine the position of the mobile terminal TE6 by three-point positioning.
Therefore, the base station BS determines whether or not the position of the mobile terminal TE6 is within the millimeter wave communication area M based on the second propagation time information. As a result, the base station BS determines whether or not a communication connection is possible between the mobile terminal TE6 and the base station BS by millimeter wave communication.

In step S31, when the propagation time of the second signal indicated by the second propagation time information is equal to or less than a predetermined threshold value Th, the base station BS proceeds to E in FIG. 5 and uses the position of the mobile terminal TE3 to provide direction information. Is generated (step S16).
That is, in step S31, the base station BS determines that the mobile terminal TE6 is located in the millimeter wave communication area M when the propagation time of the second signal indicated by the second propagation time information is equal to or less than a predetermined threshold Th. It is determined that a communication connection is possible between the mobile terminal TE6 and the base station BS by millimeter wave communication.
When the base station BS determines that the mobile terminal TE6 is located in the millimeter wave communication area M, the base station BS considers the position information of the mobile terminal TE3 as the position information of the mobile terminal TE6 and indicates the direction from the mobile terminal TE3 toward the base station BS. Generate direction information.
That is, the base station BS generates direction information based on the position information of the mobile terminal TE3, which is the source of the second reference signal corresponding to the second propagation time information.

FIG. 10 is a diagram showing the positional relationship between the mobile terminal TE6, which is the request terminal in FIG. 9, and the mobile terminal TE3, which is the connection terminal TE-2.
Since the mobile terminal TE6 has just entered the millimeter-wave communication area M from outside the millimeter-wave communication area M, the mobile terminal TE3 in the vicinity thereof is located near the outer edge of the millimeter-wave communication area M.

Since the mobile terminal TE3 is connected to the base station BS by millimeter wave communication, it is located in the millimeter wave communication area M. Further, even in a certain range around the mobile terminal TE3, the mobile terminal TE may be able to communicate with the base station BS by millimeter wave communication, and can be considered to be within the millimeter wave communication area M.

Therefore, a certain range A around the mobile terminal TE3 is set as a range in which the mobile terminal TE can communicate with the base station BS by millimeter wave communication.
The base station BS determines that the mobile terminal TE located within the range A is located within the millimeter wave communication area M.
The range A is defined by a circle a centered on the mobile terminal TE3.
The radius r of the circle a can be set by experimentally confirming that a communication connection can be made with the base station BS by millimeter wave communication using the mobile terminal TE.
Further, the radius r can be the difference between the distance L1 between the base station BS and the mobile terminal TE3 and the reachable distance L2 of the millimeter wave obtained based on the performance of the base station BS and the like.

The predetermined threshold Th is set to the time required for the second reference signal to propagate in the radius r.
As a result, the base station BS determines whether or not the mobile terminal TE6 is within the range A by determining whether or not the propagation time of the second signal indicated by the second propagation time information is equal to or less than a predetermined threshold value Th. can do.
When the propagation time of the second signal indicated by the second propagation time information is equal to or less than a predetermined threshold value Th, the distance between the mobile terminal TE3 and the mobile terminal TE6 is a radius r or less. Therefore, the mobile terminal TE6 is located within the range A. Therefore, in this case, the base station BS determines that the mobile terminal TE6 is located in the millimeter wave communication area M (step S31).

On the other hand, when the propagation time of the second signal indicated by the second propagation time information is larger than the predetermined threshold value Th, the distance between the mobile terminal TE3 and the mobile terminal TE6 becomes larger than the radius r. Therefore, the mobile terminal TE6 is located outside the range A. In this case, the base station BS determines that the mobile terminal TE6 is located outside the millimeter wave communication area M (step S31).
If it is determined that the position of the mobile terminal TE6 is outside the millimeter wave communication area M, the base station BS returns to the front of step S4 and waits for the transmission of the request notification from the mobile terminal TE again. In this case, the mobile terminal TE6 cannot communicate with the base station BS unless it is located in the millimeter wave communication area M.

In FIG. 10, the propagation time of the second signal indicated by the second propagation time information is equal to or less than a predetermined threshold value Th, and the mobile terminal TE6 is located within the range A around the mobile terminal TE3.
Therefore, the base station BS determines that the mobile terminal TE6 is located in the millimeter wave communication area M (step S31).
Further, since the mobile terminal TE6 exists within the range A, it can be determined that the mobile terminal TE6 is located in the vicinity of the mobile terminal TE3. Therefore, the base station BS regards the position of the mobile terminal TE6 as the position of the mobile terminal TE3, and generates direction information with respect to the mobile terminal TE6 based on the position information of the mobile terminal TE3 (step S16).
Subsequent processing is as described above.

In this case, even if the position of the mobile terminal TE6 cannot be obtained by three-point distance measurement because three or more propagation time informations have not been received, the position of the mobile terminal TE3 is regarded as the position of the mobile terminal TE6. Direction information can be generated.
As a result, the time required to search the direction from the mobile terminal TE6 toward the base station BS can be shortened.

In the above description, the case where the mobile terminal TE3 is located near the outer edge of the millimeter wave communication area M is shown, but if it is the connection terminal TE-2 located in the millimeter wave communication area M, the same processing is performed. Can be done.

When the mobile terminal TE6 transmits two propagation time information corresponding to the second reference signal and the base station BS receives the propagation time information corresponding to the two second reference signals, the base station BS receives these two. It is determined whether or not the mobile terminal TE6 is located in the millimeter-wave communication area M based on the propagation time information of the smaller propagation time information (step S31).
In this case, the direction information can be generated based on the mobile terminal TE having a smaller distance from the mobile terminal TE6, and more accurate direction information can be generated.

Further, in the present embodiment, when the base station BS receives three or more propagation time information, the base station BS is configured to obtain the position of the mobile terminal TE6 by three-point positioning. Even when the base station BS receives three or more propagation time information, it may be configured to proceed to steps S30 and S31 to generate direction information.

In this case, the base station BS determines whether or not the mobile terminal TE6 is located in the millimeter wave communication area M based on the propagation time information having the minimum propagation time among the plurality of propagation time information corresponding to the second reference signal. Is determined. As a result, the direction information of the mobile terminal TE6 can be generated.

[About the configuration of mobile terminals and base stations]
FIG. 11 is a block diagram showing a configuration example of the mobile terminal TE of the present embodiment.
The mobile terminal TE shown in FIG. 11 is a terminal that can be any of the above-mentioned unconnected terminal TE-1 and connected terminal TE-2.
The mobile terminal TE includes an antenna unit 12, a transmission / reception unit 14, a processing device 16, and an orientation sensor 18.
The antenna unit 12 has a plurality of antenna elements 12a and constitutes an array antenna. The antenna unit 12 has a function of adjusting the phase and amplitude of signals transmitted and received by the plurality of antenna elements 12a. As a result, the directivity direction of the antenna unit 12 is variable and controllable.
The antenna unit 12 receives the radio wave propagating in space and gives a received RF (Radio Frequency) signal to the transmitting / receiving unit 14.
Further, the antenna unit 12 radiates the transmission RF signal given from the transmission / reception unit 14 into space as a radio wave.

The transmission / reception unit 14 obtains a baseband signal by performing processing such as amplification, frequency conversion, and demodulation on the received RF signal given from the antenna unit 12. The transmission / reception unit 14 converts the obtained analog baseband signal into a digital baseband signal, and further performs a fast Fourier transform or the like on the digital baseband signal to extract data.
The transmission / reception unit 14 gives the extracted data to the processing device 16.

Further, the transmission / reception unit 14 performs an inverse fast Fourier transform on the data given from the processing device 16 to generate a digital baseband signal. The transmission / reception unit 14 converts the generated digital baseband signal into an analog baseband signal, and further performs processing such as modulation, frequency conversion, and amplification on the analog baseband signal to obtain a transmission RF signal. ..
The transmission / reception unit 14 gives a transmission RF signal to the antenna unit 12.

The processing device 16 may be composed of a computer having a storage unit such as a CPU, a memory, and a hard disk, or may be composed of a hardware circuit capable of realizing a part or all of each function of the processing device 16. You may be. Further, the processing device 16 may be configured by combining the computer and the hardware circuit.
When the processing device 16 includes a computer, a storage unit stores a computer program or the like for execution by the CPU. The CPU realizes the function of the processing device 16 by reading the computer program recorded on a non-transient recording medium that can be read by a computer such as the storage unit.

The processing device 16 (terminal processing unit) has a function of controlling the transmission / reception unit 14 and the antenna unit 12 to perform processing for making a communication connection with the base station BS and another mobile terminal TE.
The processing device 16 has a function for realizing each function of the mobile terminal TE described above.
For example, when the processing device 16 determines that a communication connection by millimeter wave communication is possible with the base station BS when the communication connection is made only with the sub 6 GHz communication with the base station BS, the processing device 16 requests the base station BS. It has a function of transmitting a notification (step S3 in FIG. 4).
Further, the processing device 16 functionally includes an inter-terminal transmission control unit 16a (inter-terminal transmission control processing), an information transmission unit 16b (propagation time information transmission processing), and a directivity direction control unit 16c (directivity direction control processing). Have in.

When the terminal-to-terminal transmission control unit 16a receives the first reference signal from the base station BS when the own terminal TE is connected to the base station BS by communication by millimeter wave communication (when the connection terminal TE-2 is used), the terminal-to-terminal transmission control unit 16a receives the first reference signal from the base station BS. It has a function (step S7 in FIG. 4) of transmitting a second reference signal including a transmission time of its own signal by a side link (wireless communication between terminals).
Thereby, the distance between the plurality of connecting terminals and the requesting terminal can be measured by the second signal.
Further, when the information transmission unit 16b receives the first reference signal and the second reference signal after transmitting the request notification and the request notification, the information transmission unit 16b transmits the propagation time information corresponding to the received signals to the base station BS. It has a function (step S8 in FIG. 4).
As a result, the mobile terminal TE can transmit the propagation time information to the base station BS when the request notification is transmitted as the request terminal.
Further, the directivity direction control unit 16c has a function of controlling the directivity direction of the antenna unit 12 and, when receiving the direction information, limiting the variable range of the directivity direction of the antenna unit 12 based on the direction information.

The azimuth sensor 18 includes a 3-axis magnetic sensor and a 3-axis acceleration sensor. The azimuth sensor 18 gives the outputs of the 3-axis magnetic sensor and the 3-axis acceleration sensor to the processing device 16.
The processing device 16 obtains the direction of the geomagnetism in the horizontal plane from the outputs of the 3-axis magnetic sensor and the 3-axis acceleration sensor. As a result, the processing device 16 can specify the orientation regardless of the orientation and orientation of the mobile terminal TE6. Therefore, the processing device 16 can control the directivity direction of the antenna unit 12 according to the direction information.

Further, the mobile terminal TE may include a GPS (Global Positioning System) receiver.
As described above, the mobile terminal TE of the present embodiment includes one provided with a GPS receiver and one not provided with a GPS receiver.

In addition, the mobile terminal TE has a plurality of a part or all of the above-mentioned parts for transmission / reception processing of a plurality of frequency bands performed on the access link such as sub 6GHz communication and millimeter wave communication, and transmission / reception processing by the side link. You may have it.

FIG. 12 is a block diagram showing a configuration example of the base station BS of the present embodiment.
The base station BS includes an antenna unit 22, a transmission / reception unit 24, and a processing device 26.
The antenna unit 22 has a plurality of antenna elements 22a and constitutes an array antenna. The antenna unit 22 has a function of adjusting the phase and amplitude of signals transmitted and received by the plurality of antenna elements 22a. As a result, the directivity direction of the antenna unit 22 is variable and controllable.
The antenna unit 22 receives the radio wave propagating in space and gives a received RF (Radio Frequency) signal to the transmitting / receiving unit 24.
Further, the antenna unit 22 radiates the transmission RF signal given from the transmission / reception unit 24 into space as a radio wave.

The transmission / reception unit 24 obtains a baseband signal by performing processing such as amplification, frequency conversion, and demodulation on the received RF signal given from the antenna unit 22. The transmission / reception unit 24 converts the obtained analog baseband signal into a digital baseband signal, and further performs a fast Fourier transform or the like on the digital baseband signal to extract data.
The transmission / reception unit 24 gives the extracted data to the processing device 26.

Further, the transmission / reception unit 24 performs an inverse fast Fourier transform on the data given from the processing device 26 to generate a digital baseband signal. The transmission / reception unit 24 converts the generated digital baseband signal into an analog baseband signal, and further performs processing such as modulation, frequency conversion, and amplification on the analog baseband signal to obtain a transmission RF signal. ..
The transmission / reception unit 24 gives a transmission RF signal to the antenna unit 22.

The processing device 26 may be composed of a computer having a storage unit such as a CPU, a memory, and a hard disk, or may be composed of a hardware circuit capable of realizing a part or all of each function of the processing device 26. You may be. Further, the processing device 26 may be configured by combining the computer and the hardware circuit.
When the processing device 26 includes a computer, a computer program or the like for execution by the CPU is stored in the storage unit. The CPU realizes the function of the processing device 26 by reading the computer program recorded on a non-transient recording medium that can be read by a computer such as the storage unit.
The processing device 26 includes a storage device 26f. The above-mentioned position database 2 is stored in the storage device 26f.

The processing device 26 (processing unit) has a function of performing processing for communication connection with the mobile terminal TE by controlling the transmission / reception unit 24 and the antenna unit 22.
The processing device 26 has a function for realizing each function of the base station BS described above.
For example, the processing device 26 includes a transmission control unit 26a (transmission control processing), a generation unit 26b (generation processing), a determination unit 26c (determination processing), an information transmission unit 26d (information transmission processing), and a communication unit 26e. (Communication processing) and functionally. The processing device 26 also has a function of performing a process of updating the position database 2.
When the transmission control unit 26a receives the request notification of the communication connection by millimeter wave communication from the request terminal, the transmission control unit 26a transmits the first reference signal to the mobile terminal TE by sub 6 GHz communication (step S5 in FIG. 4). It has a function to transmit a reference signal from the own station BS and the connection terminal TE-2.
The generation unit 26b positions the position of the unconnected terminal TE-1 which is the source of the request notification based on the position information of the position database 2 and the propagation time information, and the unconnected terminal TE-1 which is the source of the request notification. It has a function of generating direction information indicating a direction from -1 to the base station BS (step S16 in FIG. 5).
The determination unit 26c has a function of determining whether or not the position of the unconnected terminal TE-1 is within the millimeter wave communication area M (step S15 in FIG. 5).
Further, the determination unit 26c has a function of determining whether or not the unconnected terminal TE-1 which is a request terminal is located in the millimeter wave communication area M based on the propagation time information (step S31 in FIG. 4). ).
Further, when the determination unit 26c determines that the unconnected terminal TE-1 is located in the millimeter wave communication area M, the generation unit 26b transmits a second reference signal corresponding to the propagation time information used by the determination unit 26c. It has a function of generating the direction information based on the original position information (step S16 in FIG. 5).
The information transmission unit 26d has a function of transmitting direction information to the requesting terminal.
Further, the communication unit 26e has a function of communicating with the request terminal by sub 6 GHz communication (omnidirectional wireless communication) and receiving request notification and propagation time information by sub 6 GHz communication.
As a result, the request notification and the propagation time information can be received by wireless communication other than millimeter wave communication performed in the direction of each other.

The base station BS may include a part or all of the above-mentioned parts in order to perform transmission / reception processing of a plurality of frequency bands such as sub 6 GHz communication and millimeter wave communication.

〔others〕
It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive.
In the present embodiment, the case where the propagation time information transmitted by the mobile terminal TE6 to the base station BS includes the transmission time and the reception time of the reference signal received by the mobile terminal TE6 is shown. However, for the propagation time information, for example, the mobile terminal TE6 may obtain the propagation time of the reference signal based on the transmission time and the reception time of the reference signal, and include this propagation time in the propagation time information.
In this case, the base station BS that has received the propagation time information can use the propagation time included in the propagation time information as it is.

Further, in the present embodiment, the case where the direction information is information indicating the direction from the mobile terminal TE6 to the base station BS is shown, but the direction information is from one to the other between the mobile terminal TE6 and the base station BS. It suffices to indicate the direction to face, and may be information indicating the direction from the base station BS to the mobile terminal TE6.

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 modifications within the scope.

1 Mobile communication system 2 Location database (database)
2a column 2b column 2c column 2d column 12 antenna part (terminal antenna)
12a Antenna element 14 Transmission / reception unit 16 Processing device (terminal processing unit)
16a Inter-terminal transmission control unit 16b Information transmission unit 16c Directional direction control unit 18 Directional sensor 22 Antenna unit (antenna)
22a Antenna element 26 Processing device (processing unit)
26a Transmission control unit 26b Generation unit 26c Judgment unit 26d Information transmission unit 26e Communication unit 26f Storage device A Range BS Base station C Cell L1 Distance L2 Reachable distance M Millimeter wave communication area TE Mobile terminal TE-1 Unconnected terminal TE-2 Connection terminal TE1, TE2, TE3, TE4, TE5, TE6, TE7, TE8 Mobile terminal a circle r radius

Claims (9)

A base station that performs wireless communication with multiple mobile terminals in directions of each other.
An antenna with controllable directivity and
A processing unit that performs processing related to the wireless communication by controlling the antenna is provided.
The processing unit
A process of updating a database in which location information of a plurality of connected terminals that communicate with the own station by the wireless communication among the plurality of mobile terminals is registered.
When a notification is received from the requesting terminal requesting the communication connection by the wireless communication among the plurality of mobile terminals, the signal including the time transmitted from the own station and the plurality of connected terminals is transmitted to the own station and the plurality of connected terminals. Transmission control processing to send to the terminal and
The position of the request terminal is determined based on the position information and the propagation time information of each signal generated by the request terminal that has received the plurality of signals transmitted from the own station and the plurality of connected terminals. , A generation process for generating direction information indicating a direction from one side to the other between the requesting terminal and the base station.
A base station that executes information transmission processing for transmitting the direction information to the request terminal. The signal includes a first signal transmitted by the base station and a second signal transmitted by the plurality of connecting terminals.
The base station according to claim 1, wherein in the transmission control process, when the notification is received, the first signal is transmitted to the plurality of mobile terminals that transmit the second signal in response to the reception of the first signal. .. 1. The processing unit executes a communication process of communicating with the requesting terminal by omnidirectional wireless communication and receiving the notification and the propagation time information by the omnidirectional wireless communication. Or the base station according to claim 2. The processing unit executes a determination process for determining whether or not the position of the requesting terminal is within the area where the wireless communication is possible.
The base station according to any one of claims 1 to 3, wherein in the information transmission process, when it is determined that the position of the request terminal is outside the area, the transmission of the direction information is stopped. The base station according to claim 4, wherein the area is defined based on the position information of each of the plurality of connected terminals. A mobile communication system including a plurality of mobile terminals and a base station that performs wireless communication in which the plurality of mobile terminals are directed to each other.
The base station
An antenna with controllable directivity and
A processing unit that performs processing related to the wireless communication by controlling the antenna is provided.
The processing unit
A process of updating a database in which location information of a plurality of connected terminals that communicate with the own station by the wireless communication among the plurality of mobile terminals is registered.
When a notification is received from the requesting terminal requesting the communication connection by the wireless communication among the plurality of mobile terminals, the signal including the time transmitted from the own station and the plurality of connected terminals is transmitted to the own station and the plurality of connected terminals. Transmission control processing to send to the terminal and
The position of the request terminal is determined based on the position information and the propagation time information of each signal generated by the request terminal that has received the plurality of signals transmitted from the own station and the plurality of connected terminals. , A generation process for generating direction information indicating a direction from one side to the other between the requesting terminal and the base station.
The information transmission process of transmitting the direction information to the request terminal is executed.
The plurality of mobile terminals
With a terminal antenna whose directivity can be controlled,
A terminal processing unit that performs processing related to the wireless communication by controlling the terminal antenna is provided.
The terminal processing unit
A mobile communication system that controls the directivity direction of the antenna and, when receiving the direction information, executes a directivity control process that limits a variable range of the directivity direction of the antenna based on the direction information. The signal includes a first signal transmitted by the base station and a second signal transmitted by the plurality of connecting terminals.
The terminal processing unit
The mobile communication system according to claim 6, wherein when the first signal is received, the terminal-to-terminal transmission control process of transmitting the second signal by inter-terminal wireless communication is executed. 6. Item 7. The mobile communication system according to item 7. It is an information generation method for generating direction information, which is executed by a base station that performs wireless communication in which directivity is directed to each other with a plurality of mobile terminals.
A step of updating a database in which location information of a plurality of connected terminals that communicate with the own station by the wireless communication among the plurality of mobile terminals is registered, and a step of updating the database.
When a notification is received from the requesting terminal requesting the communication connection by the wireless communication among the plurality of mobile terminals, the signal including the time transmitted from the own station and the plurality of connected terminals is transmitted to the own station and the plurality of connected terminals. Steps to send to the terminal and
The position of the request terminal is determined based on the position information and the propagation time information of each signal generated by the request terminal that has received the plurality of signals transmitted from the own station and the plurality of connected terminals. , A step of generating directional information indicating a direction from one to the other between the requesting terminal and the base station.
An information generation method including a step of transmitting the direction information to the request terminal.

Images