Relay device

Abstract

To provide a relay device capable of securely providing desired services to a terminal in relaying a radio signal, while suppressing cost increase.SOLUTION: A relay device 10 includes a first control part 23 and a second control part 33. The second control part 33 transmits information on a specific allocated frequency band FB associated with reception power of a second radio signal exceeded a threshold value to the first control part 23 if reception power of the second radio signal received by a second reception antenna 31 exceeds the threshold value. The second control part 33 maintains a second directivity pattern P2 associated with reception power of a second radio signal having the maximum value among reception powers of the plurality of second radio signals associated with the specific allocated frequency band FB. The first control part 23 maintains a first directivity pattern P1 associated with reception power of a first radio signal having the maximum value among reception powers of the plurality of first radio signals associated with the specific allocated frequency band FB upon receiving information on the specific allocated frequency band FB.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a relay device.

Background Art

[0002] Generally, base stations are installed for each telecommunications carrier, and a fixed frequency band is allocated to each telecommunications carrier. Each telecommunications carrier radiates radio signals in the allocated frequency band from the installed base stations to provide services to terminals subscribed to the telecommunications carrier.

[0003] On the other hand, in order for a terminal to receive services from a subscribed telecommunications carrier, it must be able to correspond to the frequency band of the telecommunications carrier and be equipped with a SIM (Subscriber Identity Module) card in which identification information for the telecommunications carrier to identify subscribers is recorded.

[0004] With such a configuration, the terminal communicates only with the base stations of the subscribed telecommunications carrier.

[0005] By the way, in order to expand the coverage of the base station, a technique of installing a relay device that performs wireless relaying between the base station and the terminal is known (see, for example, Patent Document 1).

[0006] In the technique disclosed in Patent Document 1, the relay device receives radio signals radiated from an outdoor base station with an outdoor antenna. The relay device relays the received radio signals to an indoor antenna and re-radiates the radio signals from the indoor antenna. Indoors, the terminal receives the radio signals re-radiated from the indoor antenna.

[0007] In such a configuration, the relay device controls the directivity pattern of the outdoor antenna and receives radio signals via the outdoor antenna from the base station that can most efficiently receive radio signals among a plurality of base stations installed outdoors.

Prior Art Documents

Patent Document

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, in the technology disclosed in Patent Document 1, among a plurality of base stations, the relay device relays a radio signal radiated from the base station that can receive the radio signal most efficiently.

[0010] Due to such a configuration, when the radio signal relayed by the relay device is radiated from a base station of a different telecommunications carrier from the one to which the indoor terminal subscribes, the terminal cannot receive the desired service indoors.

[0011] Here, it is conceivable to apply a "regenerative" relay technology in which the relay device relays the received radio signal by demodulating and remodulating the received radio signal.

[0012] Specifically, the relay device demodulates the received radio signal, reads the data included in the radio signal, and identifies the base station that radiated the radio signal with reference to the read data. When the base station that radiated the received radio signal is the base station of the telecommunications carrier to which the indoor terminal subscribes, the relay device fixes the directivity pattern of the outdoor antenna and relays the received radio signal to the terminal.

[0013] However, when using the "regenerative" relay technology, it is necessary to install a demodulation / modulation device in the relay device to perform demodulation and remodulation of the radio signal, which increases the cost. Therefore, in radio signal relaying, further improvement has been desired in order to surely provide the desired service to the terminal while suppressing an increase in cost.

[0014] The present invention has been made in view of the problems of such prior art. And an object of the present invention is to provide a relay device capable of surely providing a desired service to a terminal while suppressing an increase in cost in relaying a wireless signal.

Means for Solving the Problems

[0015] The relay device according to an aspect of the present invention performs wireless relaying between a base station and a terminal that are installed on an object to be installed and communicate using a predetermined allocated frequency band. The relay device includes a first antenna that is installed outside the object to be installed and receives first radio signals radiated from each of a plurality of base stations based on a first directivity pattern, and sets each of the plurality of allocated frequency bands used by the plurality of base stations as a first measurement frequency band, and measures the reception power of the first radio signals received by the first antenna for each of the first measurement frequency bands while switching the first directivity pattern, a first control unit; a second antenna that is installed inside the object to be installed and receives second radio signals radiated from the terminal based on a second directivity pattern, and sets each of the plurality of allocated frequency bands used by the plurality of base stations as a second measurement frequency band, and measures the reception power of the second radio signals received by the second antenna for each of the second measurement frequency bands while switching the second directivity pattern, a second control unit; a first relay line that communicably connects the first antenna and the second antenna; and a second relay line that communicably connects the first control unit and the second control unit. The first antenna re-radiates the second radio signals relayed from the second antenna via the first relay line based on the first directivity pattern. The second antenna re-radiates the first radio signals relayed from the first antenna via the first relay line based on the second directivity pattern. The first control unit records the measured reception power of the first radio signals in association with the information of the first directivity pattern and the allocated frequency band corresponding to the first measurement frequency band. The second control unit records the measured reception power of the second radio signals in association with the information of the second directivity pattern and the allocated frequency band corresponding to the second measurement frequency band. When the reception power of the second radio signals exceeds a threshold value, the second control unit transmits information on a specific allocated frequency band associated with the reception power of the second radio signals that exceed the threshold value to the first control unit via the second relay line. The second control unit maintains the second directivity pattern associated with the reception power of the second radio signal having the maximum value among the reception powers of the plurality of second radio signals associated with the specific allocated frequency band.When the first control unit receives the information of the specific allocated frequency band, among the received powers of a plurality of first radio signals associated with the specific allocated frequency band, it maintains the first directivity pattern associated with the received power of the first radio signal having the maximum value.

Advantages of the Invention

[0016] According to the present invention, in the relay of radio signals, it is possible to provide a relay device that can reliably provide a desired service to a terminal while suppressing an increase in cost.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5A

Figure 5B

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, the relay device according to the present embodiment will be described in detail with reference to the drawings. Note that the same or similar reference numerals are given to the same functions and configurations, and the description thereof will be omitted as appropriate.

[0019] [Overall Schematic Configuration Diagram of Relay System] First, the configuration of the relay system 1 according to the present embodiment will be described. FIG. 1 is an overall schematic configuration diagram of the relay system 1. As shown in FIG. 1, the relay system 1 includes an object to be installed 3, a relay device 10, base stations 100a to 100c, and a terminal 200. The object to be installed 3 is a fixed object such as a building and has an outer wall 3a. The inside of the object to be installed 3 is surrounded by the outer wall 3a and is called the indoor area of the object to be installed 3. The outside of the object to be installed 3 is called the outdoor area of the object to be installed 3.

[0020] The base stations 100a, 100b, and 100c are installed at different positions by communication carriers A, B, and C. Note that, among the base stations 100a, 100b, and 100c, one base station may be installed at the same position as any one of the other two base stations. Also, the base stations 100a, 100b, and 100c may be installed at the same position.

[0021] A fixed frequency band A1 is assigned to communication carrier A. Communication carrier A radiates a radio signal in the assigned frequency band A1 from base station 100a to provide services to terminals subscribed to communication carrier A. In this way, base station 100a is operated by communication carrier A and radiates a radio signal in the assigned frequency band A1.

[0022] Communication carrier B is assigned a fixed frequency band B1. Communication carrier B radiates a radio signal of the assigned frequency band B1 from base station 100b to provide services to terminals subscribing to communication carrier B. In this way, base station 100b is operated by communication carrier B and radiates a radio signal of the assigned frequency band B1.

[0023] Communication carrier C is assigned a fixed frequency band C1. Communication carrier C radiates a radio signal of the assigned frequency band C1 from base station 100c to provide services to terminals subscribing to communication carrier C. In this way, base station 100c is operated by communication carrier C and radiates a radio signal of the assigned frequency band C1.

[0024] For example, communication carriers A, B, and C are each assigned three frames with a width of 400 MHz in the 28 GHz band. Note that the frequency bands A1, B1, and C1 assigned to communication carriers A, B, and C are also referred to as the assigned frequency bands FB = A1, B1, C1.

[0025] The number of communication carriers is not limited to three and may be two or four or more. In this case, the number of base stations is also determined according to the number of communication carriers.

[0026] Each of base stations 100a, 100b, and 100c has a configuration of periodically transmitting one piece of notification information in an omnidirectional pattern (single-beam configuration), or a configuration of periodically transmitting each of a plurality of pieces of notification information while sequentially switching the directional pattern (multi-beam configuration). For example, when each of base stations 100a, 100b, and 100c radiates a radio signal in the assigned frequency band of the 28 GHz band, it has a multi-beam configuration.

[0027] Note that the omnidirectional pattern is a pattern indicating a state where the radiation intensity and reception intensity of radio waves are uniform regardless of direction. Also, the directional pattern is a pattern indicating a state where the radiation intensity and reception intensity of radio waves vary depending on direction.

[0028] The terminal 200 subscribes to one of the communication carriers A, B, and C. Specifically, the terminal 200 can correspond to the allocated frequency band FB of one of the communication carriers A, B, and C, and is equipped with a SIM card on which the identification information for the carrier to identify subscribers is recorded. With such a configuration, the terminal 200 uses the allocated frequency band FB assigned to the subscribed communication carrier to perform wireless communication only with the base station of that communication carrier.

[0029] The terminal 200 is located indoors in the installation object 3. Therefore, there is an outer wall 3a of the installation object 3 between the base stations 100a, 100b, 100c and the terminal 200. Since the radio waves are shielded by the outer wall 3a, the terminal 200 cannot directly perform wireless communication with the base station of the subscribed communication carrier.

[0030] The relay device 10 is installed in the installation object 3 and performs wireless relaying between one of the base stations 100a, 100b, 100c and the terminal 200. The relay device 10 includes an outdoor part 20, an indoor part 30, and a relay line 40.

[0031] The outdoor part 20 is arranged on the outdoor side of the installation object 3. In this embodiment, the outdoor part 20 is arranged on the outer peripheral surface of the outer wall 3a of the installation object 3. The outdoor part 20 includes a first receiving antenna 21 and a first transmitting antenna 22. Each of the first receiving antenna 21 and the first transmitting antenna 22 has sufficient radiation efficiency in the allocated frequency bands FB = A1, B1, C1 of the communication carriers A, B, and C.

[0032] Each of the first receiving antenna 21 and the first transmitting antenna 22 is a directive variable antenna, and the directivity of the antenna can be changed. Specifically, each of the first receiving antenna 21 and the first transmitting antenna 22 has a plurality of first directivity patterns P1, and switches the first directivity pattern P1 based on the first directivity control signal from the first control unit 23 described later.

[0033] In this embodiment, the number of the first directivity patterns P1 is four. For the four first directivity patterns P1, directivity numbers P = 1, 2, 3, 4 are assigned in the plane perpendicular to the ground (elevation angle direction) from above (see FIG. 1). Note that the number of the first directivity patterns P1 is not limited to four. Also, the directivity numbers P do not necessarily need to be assigned in order from above in the plane perpendicular to the ground, and may be assigned in any order. Further, each of the first receiving antenna 21 and the first transmitting antenna 22 may have an omnidirectional pattern in addition to the plurality of first directivity patterns P1. Each of the first receiving antenna 21 and the first transmitting antenna 22 may have a plurality of first directivity patterns P1 in the plane parallel to the ground (azimuth angle direction).

[0034] The indoor unit 30 is disposed on the indoor side of the object 3 to be installed. The indoor unit 30 includes a second receiving antenna 31 and a second transmitting antenna 32. Each of the second receiving antenna 31 and the second transmitting antenna 32 has sufficient radiation efficiency in the frequency bands FB = A1, B1, C1 assigned by communication carriers A, B, and C.

[0035] Each of the second receiving antenna 31 and the second transmitting antenna 32 is a directivity variable antenna, and the directivity of the antenna can be changed. Specifically, each of the second receiving antenna 31 and the second transmitting antenna 32 has a plurality of second directivity patterns P2, and switches the second directivity patterns P2 according to a second directivity control signal from a second control unit 33 described later.

[0036] In this embodiment, the number of the second directivity patterns P2 is four. In the plane perpendicular to the ground (elevation angle direction), directivity numbers P = 11, 12, 13, and 14 are assigned to the four second directivity patterns P2 from above (see FIG. 1). Note that the number of the second directivity patterns P2 is not limited to four. Also, the directivity numbers P do not have to be assigned in order from above in the plane perpendicular to the ground, and may be assigned in any order. Furthermore, each of the second receiving antenna 31 and the second transmitting antenna 32 may have an omnidirectional pattern in addition to the plurality of second directivity patterns P2. Each of the second receiving antenna 31 and the second transmitting antenna 32 may have a plurality of second directivity patterns P2 in the plane parallel to the ground (azimuth angle direction).

[0037] The relay line 40 is composed of a coaxial cable and communicably connects the outdoor unit 20 and the indoor unit 30. Specifically, the relay line 40 penetrates the outer wall 3a of the object 3 to be installed and has one end connected to the outdoor unit 20 and the other end connected to the indoor unit 30.

[0038] Note that the relay line 40 is not limited to a coaxial cable and may be a waveguide, RoF (Radio over Fiber), or a microstrip line.

[0039] The radio signal received by the first receiving antenna 21 of the outdoor unit 20 is relayed via the relay line 40 to the second transmitting antenna 32 of the indoor unit 30 and re-radiated from the second transmitting antenna 32. Thereby, the terminal 200 can receive a radio signal in a specific assigned frequency band FB assigned by the communication carrier to one of the base stations 100a, 100b, and 100c. Note that the radio signal received by the first receiving antenna 21 and the radio signal re-radiated from the second transmitting antenna 32 are referred to as the first radio signal.

[0040] The radio signal received by the second receiving antenna 31 inside the house 30 is relayed via the relay line 40 to the first transmitting antenna 22 outside the house 20 and re-radiated from the first transmitting antenna 22. As a result, the terminal 200 can transmit a radio signal in a specific allocated frequency band FB assigned to the communicating carrier to any one of the base stations 100a, 100b, 100c. Note that the radio signal received by the second receiving antenna 31 and the radio signal re-radiated from the first transmitting antenna 22 are referred to as the second radio signal.

[0041] [Functional Block Configuration of Relay Device] Next, the configuration of the relay device 10 will be described. Specifically, the configuration of the outside of the house 20, the configuration of the inside of the house 30, and the configuration of the relay line 40 will be described in order. FIG. 2 is a functional block configuration diagram of the relay device 10.

[0042] [Configuration of the Outside of the House] First, the configuration of the outside of the house 20 will be described. As shown in FIG. 2, the outside of the house 20 includes a first receiving antenna 21, a first transmitting antenna 22, a first control unit 23, and a first coupler 24.

[0043] The first receiving antenna 21 is disposed on the outdoor side of the object 3 to receive the first radio signal radiated from each of the base stations 100a, 100b, 100c based on the first directivity pattern P1. The first transmitting antenna 22 is disposed on the outdoor side of the object 3 to re-radiate the second radio signal relayed via the relay line 40 based on the first directivity pattern P1.

[0044] The first directivity pattern P1 of the first receiving antenna 21 is linked with the first directivity pattern P1 of the first transmitting antenna 22. Therefore, the directivity of the first receiving antenna 21 is directed in the same direction as the directivity of the first transmitting antenna 22. As a result, the first receiving antenna 21 and the first transmitting antenna 22 can direct their directivity in the direction in which the base station capable of communicating with the terminal 200 among the base stations 100a, 100b, 100c is installed.

[0045] The isolation between the first receiving antenna 21 and the first transmitting antenna 22 is achieved by physical separation such as increasing the distance between the first receiving antenna 21 and the first transmitting antenna 22 or placing a shield between them. Instead of physical separation, existing methods such as antenna pattern, antenna cancellation, and analog canceller may also be used.

[0046] Note that the first receiving antenna 21 and the first transmitting antenna 22 are collectively referred to as the first antenna.

[0047] The first control unit 23 is connected to the output side of the first receiving antenna 21 via the first coupler 24. The first control unit 23 is directly connected to the input sides of the first receiving antenna 21 and the first transmitting antenna 22. The first control unit 23 is connected to the second control unit 33 in the indoor unit 30 via the relay line 40.

[0048] The first control unit 23 outputs a first directivity control signal to the input sides of the first receiving antenna 21 and the first transmitting antenna 22 to switch the first directivity pattern P1 of the first receiving antenna 21 and the first directivity pattern P1 of the first transmitting antenna 22. The first directivity control signal includes information regarding the first directivity pattern P1 to be switched.

[0049] When the first directivity control signal is input, the first receiving antenna 21 switches the first directivity pattern P1 based on the information regarding the first directivity pattern P1 to be switched, which is included in the first directivity control signal.

[0050] The first receiving antenna 21 receives the first radio signals radiated from each of the base stations 100a, 100b, and 100c based on the switched first directivity pattern P1. When the first receiving antenna 21 receives the first radio signal, it inputs the first radio signal to the first control unit 23 via the first coupler 24.

[0051] As will be described later, the first control unit 23 sets each of the allocated frequency bands FB = A1, B1, and C1 used in the base stations 100a, 100b, and 100c as the first measurement frequency band. The first control unit 23 measures the reception power of the first radio signal received by the first receiving antenna 21 for each first measurement frequency band while switching the first directivity pattern P1 of the first receiving antenna 21.

[0052] Similar to the first receiving antenna 21, when a first directivity control signal is input to the first transmitting antenna 22, the first directivity pattern P1 is switched based on the information regarding the first directivity pattern P1 to be switched, which is included in the first directivity control signal.

[0053] The first control unit 23 associates the measured reception power of the first radio signal with the information of the first directivity pattern P1 at the time of the measurement and the allocated frequency band FB corresponding to the first measurement frequency band at the time of the measurement, and records it in the first measurement table. Note that when the first control unit 23 records the reception power of the first radio signal measured this time by associating it with the information of the first directivity pattern P1 and the allocated frequency band FB, if the reception power of the first radio signal measured last time exists in the first measurement table, the reception power of the first radio signal measured this time is overwritten. Also, in the present embodiment, the information of the first directivity pattern P1 is the directivity number P assigned to the first directivity pattern P1.

[0054] As will be described later, when the first control unit 23 receives information on a specific allocated frequency band FB from the second control unit 33 in the indoor unit 30 via the relay line 40, the first control unit 23 extracts the reception power of the first radio signal having the maximum value from among the reception powers of a plurality of first radio signals associated with the specific allocated frequency band FB from the first measurement table. The first control unit 23 further extracts the first directivity pattern P1 associated with the reception power of the first radio signal having the maximum value from the first measurement table.

[0055] The first control unit 23 includes information regarding the extracted first directivity pattern P1 in the first directivity control signal and outputs it to the input sides of the first receiving antenna 21 and the first transmitting antenna 22. When the first control unit 23 outputs the first directivity control signal, it waits for a time TW and maintains the extracted first directivity pattern P1. Note that the time TW is also referred to as the standby time.

[0056] When each of the first receiving antenna 21 and the first transmitting antenna 22 receives a first directivity control signal including information regarding the extracted first directivity pattern P1, it switches the first directivity pattern P1 based on the information regarding the extracted first directivity pattern P1.

[0057] The first receiving antenna 21 receives a first radio signal in a specific allocated frequency band FB based on the extracted first directivity pattern P1 by the switching. The first transmitting antenna 22 re-radiates a second radio signal in a specific allocated frequency band FB relayed via the relay line 40 based on the extracted first directivity pattern P1 by the switching.

[0058] The first coupler 24 branches the first radio signal received by the first receiving antenna 21 and inputs the first radio signal to the first control unit 23 and the relay line 40.

[0059] [Configuration inside the house] Next, the configuration of the inside of the house 30 will be described. As shown in FIG. 2, the inside of the house 30 includes a second receiving antenna 31, a second transmitting antenna 32, a second control unit 33, and a second coupler 34.

[0060] The second receiving antenna 31 is disposed on the indoor side of the installed object 3 and receives a second radio signal radiated from the terminal 200 based on the second directivity pattern P2. The second transmitting antenna 32 is disposed on the indoor side of the installed object 3 and re-radiates the first radio signal relayed via the relay line 40 based on the second directivity pattern P2.

[0061] The second directivity pattern P2 of the second receiving antenna 31 is linked with the second directivity pattern P2 of the second transmitting antenna 32. Therefore, the directivity of the second receiving antenna 31 is oriented in the same direction as the directivity of the second transmitting antenna 32. Thereby, the second receiving antenna 31 and the second transmitting antenna 32 can direct their directivities in the direction where the terminal 200 is located.

[0062] The isolation between the second receiving antenna 31 and the second transmitting antenna 32 is achieved by physical separation such as increasing the distance between the second receiving antenna 31 and the second transmitting antenna 32 or placing a shielding object between the second receiving antenna 31 and the second transmitting antenna 32. Note that, instead of physical separation, existing methods such as antenna pattern, antenna cancellation, and analog canceller may be used.

[0063] Note that the second receiving antenna 31 and the second transmitting antenna 32 are collectively referred to as the second antenna.

[0064] The second control unit 33 is connected to the output side of the second receiving antenna 31 via the second coupler 34. The second control unit 33 is directly connected to the input sides of the second receiving antenna 31 and the second transmitting antenna 32. The second control unit 33 is connected to the first control unit 23 of the outdoor unit 20 via the relay line 40.

[0065] The second control unit 33 outputs a second directivity control signal to the input sides of the second receiving antenna 31 and the second transmitting antenna 32 to switch the second directivity pattern P2 of the second receiving antenna 31 and the second directivity pattern P2 of the second transmitting antenna 32. The second directivity control signal includes information regarding the second directivity pattern P2 to be switched.

[0066] When the second directivity control signal is input, the second receiving antenna 31 switches the second directivity pattern P2 based on the information regarding the second directivity pattern P2 to be switched, which is included in the second directivity control signal.

[0067] The second receiving antenna 31 receives the second radio signal radiated from the terminal 200 based on the switched second directivity pattern P2. When the second receiving antenna 31 receives the second radio signal, it inputs the second radio signal to the second control unit 33 via the second coupler 34.

[0068] As will be described later, the second control unit 33 sets each of the assigned frequency bands FB = A1, B1, C1 used in the base stations 100a, 100b, 100c as the second measurement frequency band. The second control unit 33 measures the received power of the second radio signal received by the second receiving antenna 31 for each second measurement frequency band while switching the second directivity pattern P2 of the second receiving antenna 31.

[0069] Similar to the second receiving antenna 31, when the second directivity control signal is input to the second transmitting antenna 32, the second transmitting antenna 32 switches the second directivity pattern P2 based on the information regarding the second directivity pattern P2 to be switched, which is included in the second directivity control signal.

[0070] The second control unit 33 associates the measured received power of the second radio signal with the information of the second directivity pattern P2 at the time of measurement and the assigned frequency band FB corresponding to the second measurement frequency band at the time of measurement, and records it in the second measurement table. When the second control unit 33 associates and records the received power of the second radio signal measured this time with the information of the second directivity pattern P2 and the assigned frequency band FB, if the received power of the second radio signal measured last time exists in the second measurement table, the received power of the second radio signal measured this time is overwritten. Also, in the present embodiment, the information of the second directivity pattern P2 is the directivity number P assigned to the second directivity pattern P2.

[0071] As will be described later, when the reception power of the second radio signal exceeds the threshold TH, the second control unit 33 extracts a specific allocated frequency band FB associated with the reception power of the second radio signal that has exceeded the threshold TH from the second measurement table. When the second control unit 33 extracts the specific allocated frequency band FB, it transmits information on the extracted specific allocated frequency band FB to the first control unit 23 in the outdoor unit 20 via the relay line 40.

[0072] Also, when the second control unit 33 extracts the specific allocated frequency band FB, it extracts the reception power of the second radio signal having the maximum value among the reception powers of a plurality of second radio signals associated with the specific allocated frequency band FB from the second measurement table. Further, the second control unit 33 extracts the second directivity pattern P2 associated with the reception power of the second radio signal having the maximum value from the second measurement table.

[0073] The second control unit 33 includes information on the extracted second directivity pattern P2 in the second directivity control signal and outputs it to the input sides of the second receiving antenna 31 and the second transmitting antenna 32. When the second control unit 33 outputs the second directivity control signal, it records the maximum value of the power value of the second radio signal while maintaining the extracted second directivity pattern P2 for a time TW.

[0074] When a second directivity control signal including information on the extracted second directivity pattern P2 is input to each of the second receiving antenna 31 and the second transmitting antenna 32, each of them switches the second directivity pattern P2 based on the information on the extracted second directivity pattern P2.

[0075] The second receiving antenna 31 receives the second radio signal in the specific allocated frequency band FB based on the extracted second directivity pattern P2 by the switching. The second transmitting antenna 32 re-radiates the first radio signal in the specific allocated frequency band FB relayed via the relay line 40 based on the extracted second directivity pattern P2 by the switching.

[0076] The second coupler 34 branches the second radio signal received by the second receiving antenna 31 and inputs the second radio signal to the second control unit 33 and the relay line 40.

[0077] [Configuration of Relay Line] Next, the configuration of the relay line 40 will be described. As shown in FIG. 2, the relay line 40 includes an inter-antenna relay line 40a, an inter-antenna relay line 40b, and an inter-control-unit relay line 40c. One end of the inter-antenna relay line 40a is connected to the first receiving antenna 21 via the first coupler 24, and the other end is connected to the second transmitting antenna 32. With such a configuration, the inter-antenna relay line 40a communicably connects the first receiving antenna 21 and the second transmitting antenna 32.

[0078] One end of the inter-antenna relay line 40b is connected to the second receiving antenna 31 via the second coupler 34, and the other end is connected to the first transmitting antenna 22. With such a configuration, the inter-antenna relay line 40b communicably connects the second receiving antenna 31 and the first transmitting antenna 22. Note that the inter-antenna relay lines 40a and 40b are collectively referred to as the first relay line.

[0079] One end of the inter-control-unit relay line 40c is connected to the first control unit 23, and the other end is connected to the second control unit 33. With such a configuration, the inter-control-unit relay line 40c communicably connects the first control unit 23 and the second control unit 33. The first control unit 23 and the second control unit 33 can communicate with each other via the inter-control-unit relay line 40c. Note that the communication between the first control unit 23 and the second control unit 33 via the inter-control-unit relay line 40c is also referred to as inter-control-unit communication. Also, the inter-control-unit relay line 40c is referred to as the second relay line.

[0080] [Functional Block Configuration of First Control Unit] Next, the configuration of the first control unit 23 will be described. FIG. 3A is a functional block diagram of the first control unit 23. FIG. 3B is a diagram for explaining the state of the first radio signal input to the first control unit 23. The first control unit 23 has a function of measuring the reception power of the first radio signal radiated from each of the base stations 100a, 100b, and 100c, and a function of controlling the directivities of the first receiving antenna 21 and the first transmitting antenna 22.

[0081] As shown in FIG. 3A, the first control unit 23 includes a first mixer 231, a VCO (Voltage-Controled Oscillator) 233, a first band-pass filter 235, a first power measurement unit 237, a first power value storage unit 241, a frequency setting unit 243, and a first directivity control unit 245.

[0082] The first radio signal input from the first coupler 24 is at least one of the following radio signals (see (1) in FIG. 3B). · A radio signal having a frequency fA in the assigned frequency band FB = A1 assigned to communication carrier A and used by the base station 100a. · A radio signal having a frequency fB in the assigned frequency band FB = B1 assigned to communication carrier B and used by the base station 100b. · A radio signal having a frequency fC in the assigned frequency band FB = C1 assigned to communication carrier C and used by the base station 100c.

[0083] The first mixer 231 multiplies the first radio signal input from the first coupler 24 by the output of the VCO 233 to perform frequency down-conversion on the first radio signal. As a result, the frequency of the first radio signal input from the first coupler 24 is converted to a lower frequency.

[0084] Specifically, the frequency setting unit 243 pre-stores the frequencies fA, fB, and fC of the assigned frequency bands FB = A1, B1, C1 and the center frequency fF of the passband of the first band-pass filter 235. At the start of measurement, the frequency setting unit 243 reads the frequencies fA, fB, and fC of the assigned frequency bands FB = A1, B1, C1 and the center frequency fF of the passband of the first band-pass filter 235.

[0085] Note that the passband width of the first band-pass filter 235 is narrower than the bandwidths of the assigned frequency bands FB = A1, B1, C1 assigned to communication carriers A, B, and C. For example, when three frames with a width of 400 MHz in the 28 GHz band are assigned to the assigned frequency bands FB = A1, B1, C1, the passband width of the first band-pass filter 235 is 400 MHz or less.

[0086] When the first control unit 23 measures the received power of the first radio signal in the assigned frequency band FB = A1, the frequency setting unit 243 sets the frequency fV of the output sine wave of the VCO 233 to fA - fF. The first mixer 231 multiplies the first radio signal input from the first coupler 24 by the output of the VCO 233 to convert the frequency of the first radio signal to any one of the frequencies fA - fV (= fF), fB - fV, and fC - fV.

[0087] The first radio signal frequency-converted by the first mixer 231 is input to the first band-pass filter 235. The first band-pass filter 235 allows only signals in the frequency band near the passband to pass through. Therefore, when the first radio signal has the frequencies fB - fV and fC - fV, the first radio signal is attenuated by the first band-pass filter 235. That is, when the first radio signal input to the first band-pass filter 235 is any one of the radio signals in the assigned frequency bands FB = B1, C1 radiated from the base stations 100b and 100c, it is attenuated by the first band-pass filter 235.

[0088] On the one hand, when the first radio signal has a frequency fA - fV (= fF), the first band - pass filter 235 allows the first radio signal to pass through without attenuation. That is, when the first radio signal input to the first band - pass filter 235 is a radio signal in the assigned frequency band FB = A1 radiated from the base station 100a, it passes through the first band - pass filter 235 without attenuation. Therefore, when the first radio signal has a frequency fA - fV (= fF), the first radio signal passing through the first band - pass filter 235 has a power proportional to the received power of the first radio signal in the assigned frequency band FB = A1 radiated from the base station 100a.

[0089] The first power measurement unit 237 measures the power of the first radio signal output from the first band - pass filter 235. The first power value storage unit 241 associates the measured power value of the first radio signal with the directivity number P assigned to the first directivity pattern P1 at the time of measurement and the assigned frequency band FB = A1, and stores it in the first measurement table as the received power of the first radio signal.

[0090] When the first control unit 23 measures the received power of the first radio signal in the assigned frequency band FB = B1, the frequency setting unit 243 sets the frequency fV of the output sine wave of the VCO 233 to fB - fF. The first mixer 231 multiplies the first radio signal input from the first coupler 24 by the output of the VCO 233 (see (2) in FIG. 3B) to convert the frequency of the first radio signal to any one of the frequencies fA - fV, fB - fV (= fF), fC - fV (see (3) in FIG. 3B).

[0091] The first radio signal frequency-converted by the first mixer 231 is input to the first band-pass filter 235. The first band-pass filter 235 allows only signals in the frequency band near the passband to pass through. Therefore, when the first radio signal has frequencies fA - fV, fC - fV, the first radio signal is attenuated by the first band-pass filter 235. That is, when the first radio signal input to the first band-pass filter 235 is either a radio signal in the assigned frequency band FB = A1, C1 radiated from the base stations 100a, 100c, it is attenuated by the first band-pass filter 235.

[0092] On the other hand, when the first radio signal has a frequency fB - fV (= fF), the first radio signal passes through the first band-pass filter 235 without being attenuated. That is, when the first radio signal input to the first band-pass filter 235 is a radio signal in the assigned frequency band FB = B1 radiated from the base station 100b, it passes through the first band-pass filter 235 without being attenuated. Therefore, when the first radio signal has a frequency fB - fV, the first radio signal that has passed through the first band-pass filter 235 has a power proportional to the received power of the first radio signal in the assigned frequency band FB = B1 radiated from the base station 100b (see (4) in FIG. 3B).

[0093] The first power measurement unit 237 measures the power of the first radio signal output from the first band-pass filter 235. The first power value storage unit 241 associates the measured power value of the first radio signal with the directivity number P assigned to the first directivity pattern P1 at the time of measurement and the assigned frequency band FB = B1, and stores it in the first measurement table as the received power of the first radio signal.

[0094] When the first control unit 23 measures the reception power of the first radio signal in the assigned frequency band FB = C1, the frequency setting unit 243 sets the frequency fV of the output sine wave of the VCO 233 to fC - fF. In this case, the first mixer 231 multiplies the first radio signal input from the first coupler 24 by the output of the VCO 233 to convert the frequency of the first radio signal to any of the frequencies fA - fV, fB - fV, fC - fV (= fF).

[0095] The first radio signal frequency - converted by the first mixer 231 is input to the first band - pass filter 235. The first band - pass filter 235 allows only signals in the frequency band near the pass - band to pass through. Therefore, when the first radio signal has frequencies fA - fV, fB - fV, the first radio signal is attenuated by the first band - pass filter 235. That is, when the first radio signal input to the first band - pass filter 235 is any of the radio signals in the assigned frequency bands FB = A1, B1 radiated from the base stations 100a, 100b, it is attenuated by the first band - pass filter 235.

[0096] On the other hand, when the first radio signal has the frequency fC - fV (= fF), the first radio signal passes through the first band - pass filter 235 without being attenuated. That is, when the first radio signal input to the first band - pass filter 235 is the radio signal in the assigned frequency band FB = C1 radiated from the base station 100c, it passes through the first band - pass filter 235 without being attenuated. Therefore, when the first radio signal has the frequency fC - fV, the first radio signal that has passed through the first band - pass filter 235 has a power proportional to the reception power of the first radio signal in the assigned frequency band FB = C1 radiated from the base station 100c.

[0097] The first power measurement unit 237 measures the power of the first radio signal output from the first band - pass filter 235. The first power value storage unit 241 associates the measured power value of the first radio signal with the directivity number P assigned to the first directivity pattern P1 at the time of measurement and the assigned frequency band FB = C1, and records it in the first measurement table as the reception power of the first radio signal.

[0098] In addition, in the first mixer 231, the frequency of the first radio signal is converted not only to any one of the frequencies fA - fV, fB - fV, fC - fV, but also to any one of the frequencies fA + fV, fB + fV, fC + fV. However, the first radio signal converted to any one of the frequencies fA + fV, fB + fV, fC + fV is attenuated by the first band - pass filter 235.

[0099] Also, as will be described later, in the initial access procedure, each of the base stations 100a, 100b, 100c intermittently radiates the first radio signal (notification information). Therefore, the first power measurement unit 237 may measure the power value of the first radio signal over a certain period. In this case, the first power measurement unit 237 outputs the average value or the maximum value of the power values of the first radio signal measured within a certain period to the first power value storage unit 241 as the reception power of the first radio signal. For example, the length of the certain period is 20 ms, which is the transmission period of the first radio signal including the notification information. Note that the notification information transmitted in the initial access procedure is also referred to as an SS (Synchronization Signal) / PBCH (Physical Broadcast CHannel) block (synchronization signal / notification channel block).

[0100] When the first power value storage unit 241 records the measured power value of the first radio signal in the first measurement table, it notifies the frequency setting unit 243 of the directivity number P associated with the power value of the first radio signal.

[0101] The frequency setting unit 243 determines whether the notified directivity number P is the maximum value among the plurality of directivity numbers P assigned to the plurality of first directivity patterns P1. When the frequency setting unit 243 determines that the notified directivity number P is not the maximum value, it increments the directivity number P. The frequency setting unit 243 inputs the incremented directivity number P to the first directivity control unit 245.

[0102] When the incremented directivity number P is input, the first directivity control unit 245 outputs a first directivity control signal including a first directivity pattern P1 assigned to the directivity number P to the first receiving antenna 21 and the first transmitting antenna 22. In this way, until the directivity number P reaches the maximum value, each time the power value of the first radio signal is recorded in the first measurement table, the first directivity control unit 245 sequentially switches the first directivity pattern P1.

[0103] On the other hand, when the frequency setting unit 243 determines that the notified directivity number P is the maximum value, it resets the directivity number P to 1 and changes the frequency fV of the output sine wave of the VCO 233.

[0104] For example, when the frequency fV is set to fA - fF, the frequency setting unit 243 changes the frequency fV to fB - fF. When the frequency fV is set to fB - fF, the frequency setting unit 243 changes the frequency fV to fC - fF. When the frequency fV is set to fC - fF, the frequency setting unit 243 changes the frequency fV to fA - fF.

[0105] In this way, each time the directivity number P reaches the maximum value, the frequency setting unit 243 sequentially switches the frequency fV of the output sine wave of the VCO 233.

[0106] FIG. 4 is a diagram showing an example of the first measurement table. As shown in FIG. 4, the power value of the first radio signal measured by the first power measurement unit 237 is recorded in association with the assigned frequency band FB at the time of measurement and the directivity number P assigned to the first directivity pattern P1 at the time of measurement. Note that the first power value storage unit 241 stores in advance a plurality of sets of the assigned frequency band FB and the directivity number P assigned to the first directivity pattern P1 shown in FIG. 4.

[0107] As described above, since the power value of the first radio signal recorded in the first measurement table is proportional to the received power of the first radio signal, it can be regarded as the received power of the first radio signal. Note that in the first measurement table, instead of the assigned frequency band FB = A1, B1, C1, communication carriers A, B, C to which the assigned frequency band FB = A1, B1, C1 is assigned may be used.

[0108] With such a configuration, the first control unit 23 sets each of the assigned frequency bands FB = A1, B1, C1 as the first measurement frequency band, and for each first measurement frequency band, passes the first radio signal through the first band-pass filter 235 to measure the received power of the first radio signal. The first control unit 23 uses the first power value storage unit 241 to associate and record the measured received power of the first radio signal with a set consisting of the assigned frequency band FB corresponding to the first measurement frequency band and the directivity number P assigned to the first directivity pattern P1.

[0109] [Functional Block Configuration of the Second Control Unit] Next, the configuration of the second control unit 33 will be described. FIG. 5A is a functional block configuration diagram of the second control unit 33. FIG. 5B is a diagram for explaining the state of the second radio signal input to the second control unit 33. The second control unit 33 has a function of measuring the received power of the second radio signal radiated from the terminal 200 and a function of controlling the directivities of the second receiving antenna 31 and the second transmitting antenna 32.

[0110] As shown in FIG. 5A, the second control unit 33 includes a second mixer 331, an LO (Local Oscillator) 333, second band-pass filters 335a, 335b, 335c, second power measurement units 337a, 337b, 337c, a second power value storage unit 341, and a second directivity control unit 343.

[0111] The second radio signal input from the second coupler 34 is at least one of the following radio signals (see (1) in FIG. 5B). · A radio signal having a frequency fA of the assigned frequency band FB (i.e., the assigned frequency band FB that the terminal 200 uses when the terminal 200 subscribes to the communication carrier A) assigned to the communication carrier A and used by the base station 100a. · A radio signal having a frequency fB of the assigned frequency band FB (i.e., the assigned frequency band FB that the terminal 200 uses when the terminal 200 subscribes to the communication carrier B) assigned to the communication carrier B and used by the base station 100b. · A radio signal having a frequency fC of the assigned frequency band FB (i.e., the assigned frequency band FB that the terminal 200 uses when the terminal 200 subscribes to the communication carrier C) assigned to the communication carrier C and used by the base station 100c.

[0112] The second mixer 331 multiplies the second radio signal input from the second coupler 34 by the output of the LO 333 to perform frequency down-conversion on the second radio signal. As a result, the frequency of the second radio signal input from the second coupler 34 is converted to a lower frequency.

[0113] Specifically, when the second control unit 33 simultaneously measures the reception power of the first radio signal in the assigned frequency bands FB = A1, B1, C1, the LO 333 outputs a signal with an oscillation frequency fO (see (2) in FIG. 5B). The second mixer 331 multiplies the second radio signal input from the second coupler 34 by the output of the VO 333 to convert the frequency of the second radio signal to any of the frequencies fA - fO, fB - fO, fC - fO (see (3) in FIG. 5B).

[0114] The second radio signal frequency-converted by the second mixer 331 is input to the second band-pass filters 335a, 335b, 335c. The center frequencies of the passbands of the second band-pass filters 335a, 335b, 335c are set to fA - fO, fB - fO, fC - fO.

[0115] Note that the passband widths of the second band-pass filters 335a, 335b, and 335c are narrower than the bandwidths of the allocated frequency bands FB = A1, B1, and C1 assigned to communication carriers A, B, and C. For example, when three frames with a width of 400 MHz in the 28 GHz band are allocated to the allocated frequency bands FB = A1, B1, and C1, the passband widths of the second band-pass filters 335a, 335b, and 335c are 400 MHz or less.

[0116] Each of the second band-pass filters 335a, 335b, and 335c passes only signals in the frequency band near the passband. Therefore, when the second radio signal has a frequency fA - fO, the second radio signal is attenuated by the second band-pass filters 335b and 335c and passes through the second band-pass filter 335a without being attenuated (see (4) in FIG. 5B). Therefore, when the second radio signal has a frequency fA - fO, the second radio signal that has passed through the second band-pass filter 335a has a power proportional to the received power of the second radio signal in the allocated frequency band FB = A1 radiated from the terminal 200.

[0117] When the second radio signal has a frequency fB - fO, the second radio signal is attenuated by the second band-pass filters 335a and 335c and passes through the second band-pass filter 335b without being attenuated (see (4) in FIG. 5B). Therefore, when the second radio signal has a frequency fB - fO, the second radio signal that has passed through the second band-pass filter 335b has a power proportional to the received power of the second radio signal in the allocated frequency band FB = B1 radiated from the terminal 200.

[0118] When the second radio signal has a frequency fC - fO, the second radio signal is attenuated by the second band-pass filters 335a and 335b and passes through the second band-pass filter 335c without being attenuated (see (4) in FIG. 5B). Therefore, when the second radio signal has a frequency fC - fO, the second radio signal that has passed through the second band-pass filter 335c has a power proportional to the received power of the second radio signal in the allocated frequency band FB = C1 radiated from the terminal 200.

[0119] The second power measurement unit 337a measures the power of the second radio signal output from the second bandpass filter 335a. The second power value storage unit 341 associates the measured power value of the second radio signal with the directivity number P assigned to the second directivity pattern P2 at the time of measurement and the assigned frequency band FB = A1, and stores it in the second measurement table as the received power of the second radio signal.

[0120] The second power measurement unit 337b measures the power of the second radio signal output from the second bandpass filter 335b. The second power value storage unit 341 associates the measured power value of the second radio signal with the directivity number P assigned to the second directivity pattern P2 at the time of measurement and the assigned frequency band FB = B1, and stores it in the second measurement table as the received power of the second radio signal.

[0121] The second power measurement unit 337c measures the power of the second radio signal output from the second bandpass filter 335c. The second power value storage unit 341 associates the measured power value of the second radio signal with the directivity number P assigned to the second directivity pattern P2 at the time of measurement and the assigned frequency band FB = C1, and stores it in the second measurement table as the received power of the second radio signal.

[0122] With such a configuration, the second power value storage unit 341 simultaneously records the power values of the second radio signal in the assigned frequency bands FB = A1, B1, and C1. Note that the second power value storage unit 341 stores a plurality of sets of the assigned frequency band FB and the directivity number P assigned to the second directivity pattern P2 in advance.

[0123] Also, the second power value storage unit 341 associates in advance the input from the signal lines connected to the second bandpass filters 335a, 335b, and 335c with the assigned frequency bands FB = A1, B1, and C1. For this reason, the second power value storage unit 341 can associate the measured power value of the second radio signal input from the second bandpass filter 335a with the assigned frequency band FB = A1.

[0124] For the same reason, the second power value storage unit 341 can associate the measured power value of the second radio signal input from the second band-pass filter 335b with the assigned frequency band FB = B1. The second power value storage unit 341 can associate the measured power value of the second radio signal input from the second band-pass filter 335c with the assigned frequency band FB = C1.

[0125] Note that in the second mixer 331, in addition to the frequency of the second radio signal being converted to any one of the frequencies fA - fO, fB - fO, fC - fO, it is also converted to any one of the frequencies fA + fO, fB + fO, fC + fO. However, the first radio signal converted to any one of the frequencies fA + fO, fB + fO, fC + fO is attenuated by the second band-pass filters 335a, 335b, 335c.

[0126] Also, as will be described later, in the initial access procedure, the terminal 200 transmits a second radio signal (Msg.1) as a response to the first radio signal (notification information) intermittently radiated from any one of the base stations 100a, 100b, 100c. Therefore, each of the second power measurement units 337a, 337b, 337c may measure the power value of the second radio signal over a certain period. In this case, each of the second power measurement units 337a, 337b, 337c outputs the average value or the maximum value of the power values of the second radio signal measured within a certain period to the second power value storage unit 341 as the received power of the second radio signal. For example, the length of the certain period is 20 ms, which is the transmission period of the first radio signal including the notification information.

[0127] Furthermore, in the second measurement table, instead of the assigned frequency bands FB = A1, B1, C1, communication carriers A, B, C to which the assigned frequency bands FB = A1, B1, C1 are assigned may be used.

[0128] When the second power value storage unit 341 records the power value of the second radio signal measured by the second power measurement units 337a, 337b, 337c in the second measurement table, it notifies the second directivity control unit 343 of the directivity number P associated with the power value of the second radio signal.

[0129] The second directivity control unit 343 determines whether the notified directivity number P is the maximum value among the plurality of directivity numbers P assigned to the plurality of second directivity patterns P2. When the second directivity control unit 343 determines that the notified directivity number P is not the maximum value, it increments the directivity number P.

[0130] When the second directivity control unit 343 increments the directivity number P, it outputs a second directivity control signal including the second directivity pattern P2 to which the directivity number P is assigned to the second receiving antenna 31 and the second transmitting antenna 32. In this way, every time the power value of the second radio signal measured by the second power measurement units 337a, 337b, 337c is recorded in the second measurement table until the directivity number P reaches the maximum value, the second directivity control unit 343 sequentially switches the second directivity pattern P2.

[0131] On the other hand, when the second directivity control unit 343 determines that the notified directivity number P is the maximum value, it resets the directivity number P to 11. When the second directivity control unit 343 resets the directivity number P to 11, it outputs a second directivity control signal including the second directivity pattern P2 to which the directivity number P is assigned to the second receiving antenna 31 and the second transmitting antenna 32.

[0132] With such a configuration, the second control unit 33 sets each of the assigned frequency bands FB = A1, B1, C1 as the second measurement frequency band, and for each second measurement frequency band, passes the second radio signal through the corresponding second band-pass filter to measure the received power of the second radio signal. The second control unit 33 uses the second power value storage unit 341 to record the measured received power of the second radio signal in association with a set including the assigned frequency band FB corresponding to the second measurement frequency band and the directivity number P assigned to the second directivity pattern P2.

[0133] [Operation of the Relay Device] Next, the operation of the relay device 10 will be described. Specifically, the operations of the first control unit 23 in the outdoor unit 20, the second control unit 33 in the indoor unit 30, and the initial access procedure in the relay system 1 will be described in order. Note that the relay device 10 is always powered on and receives the first radio signals radiated from each of the base stations 100a, 100b, and 100c outdoors of the object 3 to be installed.

[0134] [Operation 1 of the First Control Unit] First, the operation of the first control unit 23 will be described. FIG. 6 is a diagram showing an example of the operation flowchart of the first control unit 23. The first control unit 23 associates the power value of the first radio signal with the assigned frequency band FB and the directivity number P in the first power value storage unit 241 and records it in the first measurement table according to the flowchart shown in FIG. 6.

[0135] Specifically, as shown in FIG. 6, the first control unit 23 determines whether there is communication from the second control unit 33 (S11). When the first control unit 23 determines that there is communication from the second control unit 33, it proceeds to S51 in FIG. 7 described later. When the first control unit 23 determines that there is no communication from the second control unit 33, as described above, it associates the power value of the first radio signal with the assigned frequency band FB and the directivity number P and records it in the first measurement table (S13).

[0136] The first control unit 23 determines whether the directivity number P associated with the recorded power value of the first radio signal is the maximum value among the plurality of directivity numbers P assigned to the plurality of first directivity patterns P1 (S15). When the first control unit 23 determines that the directivity number P is not the maximum value, it increments the directivity number P (S17) and returns to S11. When the first control unit 23 determines that the directivity number P is the maximum value, it resets the directivity number P to 1 (S19).

[0137] When the first control unit 23 resets the directivity number P to 1, it determines whether the frequency fV of the output sine wave of the VCO 233 is set to fA - fF (S21). When the first control unit 23 determines that the frequency fV is set to fA - fF, it changes the frequency fV to fB - fF (S23). When the first control unit 23 changes the frequency fV to fB - fF, it sets the assigned frequency band FB of the first measurement table in the first power value storage unit 241 to B1 (S25), and returns to S11. As a result, in subsequent recordings, the power value of the first radio signal is associated with the assigned frequency band FB = B1 and recorded in the first measurement table.

[0138] On the other hand, when the first control unit 23 determines that the frequency fV is not set to fA - fF, it determines whether the frequency fV is set to fB - fF (S27). When the first control unit 23 determines that the frequency fV is set to fB - fF, it changes the frequency fV to fC - fF (S29). When the first control unit 23 changes the frequency fV to fC - fF, it sets the assigned frequency band FB of the first measurement table in the first power value storage unit 241 to C1 (S31), and returns to S11. As a result, in subsequent recordings, the power value of the first radio signal is associated with the assigned frequency band FB = C1 and recorded in the first measurement table.

[0139] On the other hand, when the first control unit 23 determines that the frequency fV is not set to fB - fF, it changes the frequency fV to fA - fF (S33). When the first control unit 23 changes the frequency fV to fA - fF, it sets the assigned frequency band FB of the first measurement table in the first power value storage unit 241 to A1 (S35), and returns to S11. As a result, in subsequent recordings, the power value of the first radio signal is associated with the assigned frequency band FB = A1 and recorded in the first measurement table.

[0140] [Operation of the First Control Unit 2] Next, the operation of the first control unit 23 when communication is received from the second control unit 33 will be described. FIG. 7 is a diagram showing an example of an operation flowchart of the first control unit 23 when communication is received from the second control unit 33. When communication is received from the second control unit 33, the first control unit 23 changes the directivity of the first receiving antenna 21 and the first transmitting antenna 22 in the direction in which the maximum power value is recorded in the frequency band assigned to the communication carrier to which the terminal 200 subscribes according to the flowchart of FIG. 7. Thereby, subsequent communication can be performed with a high SNR (Signal-Noise Ratio) between the terminal 200 and the base station of the communication carrier to which the terminal 200 subscribes. The relay device 10 maintains the directivity of the first receiving antenna 21 and the first transmitting antenna 22 for a time TW.

[0141] Specifically, as shown in FIG. 7, when the first control unit 23 determines that communication is received from the second control unit 33 (S11 in FIG. 6), it grasps a specific assigned frequency band FB detected on the indoor unit 30 side (S51). As will be described later, the specific assigned frequency band FB is the assigned frequency band FB associated with the power value of the second radio signal exceeding the threshold TH on the indoor unit 30 side.

[0142] When the first control unit 23 grasps the specific assigned frequency band FB, it determines whether the specific assigned frequency band FB is the frequency band A1 (S53). When the first control unit 23 determines that the specific assigned frequency band FB is the frequency band A1, it acquires the directivity number P that records the maximum power value with the assigned frequency band FB = A1 from the first measurement table of the first power value storage unit 241 (S55). The first control unit 23 sets the first directivity pattern P1 assigned the acquired directivity number P and changes the directivity of the first receiving antenna 21 and the first transmitting antenna 22 (S55).

[0143] Specifically, the first control unit 23 obtains the maximum power value of a plurality of first radio signals associated with the assigned frequency band FB = A1 from the first measurement table of the first power value storage unit 241. The first control unit 23 obtains the directivity number P associated with the obtained power value of the first radio signal. The first control unit 23 sets a first directivity control signal including the first directivity pattern P1 to which the obtained directivity number P is assigned, and transmits the first directivity control signal to the first receiving antenna 21 and the first transmitting antenna 22. Thereby, the first control unit 23 changes the directivities of the first receiving antenna 21 and the first transmitting antenna 22.

[0144] The first control unit 23 changes the frequency fV of the output sine wave of the VCO 233 to fA - fF (S57). When the first control unit 23 changes the frequency fV to fA - fF, it sets the assigned frequency band FB of the first measurement table in the first power value storage unit 241 to A1 (S59), and proceeds to S75. Thereby, in subsequent recordings, the power value of the first radio signal is associated with the assigned frequency band FB = A1 and recorded in the first measurement table.

[0145] On the other hand, when the first control unit 23 determines that the specific assigned frequency band FB is not the frequency band A1, it determines whether the specific assigned frequency band FB is the frequency band B1 (S61). When the first control unit 23 determines that the specific assigned frequency band FB is the frequency band B1, it obtains the directivity number P that recorded the maximum power value in the first measurement table of the first power value storage unit 241 with the assigned frequency band FB = B1 (S63). The first control unit 23 sets the first directivity pattern P1 to which the obtained directivity number P is assigned, and changes the directivities of the first receiving antenna 21 and the first transmitting antenna 22 (S63).

[0146] Specifically, the first control unit 23 obtains the maximum power value of a plurality of first radio signals associated with the assigned frequency band FB = B1 from the first measurement table of the first power value storage unit 241. The first control unit 23 obtains the directivity number P associated with the obtained power value of the first radio signal. The first control unit 23 sets a first directivity control signal including the first directivity pattern P1 to which the obtained directivity number P is assigned, and transmits the first directivity control signal to the first receiving antenna 21 and the first transmitting antenna 22. Thereby, the first control unit 23 changes the directivity of the first receiving antenna 21 and the first transmitting antenna 22.

[0147] The first control unit 23 changes the frequency fV of the output sine wave of the VCO 233 to fB - fF (S65). When the first control unit 23 changes the frequency fV to fB - fF, it sets the assigned frequency band FB of the first measurement table in the first power value storage unit 241 to B1 (S67), and proceeds to S75. Thereby, in subsequent recordings, the power value of the first radio signal is associated with the assigned frequency band FB = B1 and recorded in the first measurement table.

[0148] On the other hand, when the first control unit 23 determines that the specific assigned frequency band FB is not the frequency band B1, it obtains the directivity number P that recorded the maximum power value in the assigned frequency band FB = C1 from the first measurement table of the first power value storage unit 241 (S69). The first control unit 23 sets the first directivity pattern P1 to which the obtained directivity number P is assigned, and changes the directivity of the first receiving antenna 21 and the first transmitting antenna 22 (S71).

[0149] Specifically, the first control unit 23 obtains the maximum power value of a plurality of first radio signals associated with the assigned frequency band FB = C1 from the first measurement table of the first power value storage unit 241. The first control unit 23 obtains the directivity number P associated with the obtained power value of the first radio signal. The first control unit 23 sets a first directivity control signal including the first directivity pattern P1 to which the obtained directivity number P is assigned, and transmits the first directivity control signal to the first receiving antenna 21 and the first transmitting antenna 22. Thereby, the first control unit 23 changes the directivity of the first receiving antenna 21 and the first transmitting antenna 22.

[0150] The first control unit 23 changes the frequency fV of the output sine wave of the VCO 233 to fC - fF (S73). When the first control unit 23 changes the frequency fV to fC - fF, it sets the assigned frequency band FB of the first measurement table in the first power value storage unit 241 to C1 (S73) and proceeds to S75. Thereby, in subsequent recordings, the power value of the first radio signal is associated with the assigned frequency band FB = C1 and recorded in the first measurement table.

[0151] When the first control unit 23 sets the first measurement table, it waits for a time TW (S75). For example, if an initial access is established between the terminal 200 and the base station of the communication carrier to which the terminal 200 subscribes during the time TW, data communication is started. When data communication is started between the terminal 200 and the base station of the communication carrier to which the terminal 200 subscribes, the terminal 200 transmits a confirmation response signal each time it receives a signal from the base station. In the indoor unit 30, the second receiving antenna 31 receives the confirmation response signal transmitted from the terminal 200 as a second radio signal. At this time, when the power value of the received confirmation response signal exceeds the threshold TH, the second control unit 33 transmits the information of a specific assigned frequency band FB to the first control unit 23 again. Thereby, the current state can be maintained between the terminal 200 and the base station of the communication carrier to which the terminal 200 subscribes, and data communication is continued.

[0152] On one hand, if initial access fails to be established between the terminal 200 and the base station of the communication carrier to which the terminal 200 subscribes during the time TW, the following operations are performed in the outdoor part 20 and the indoor part 30 when the time TW elapses. In the outdoor part 20, the first control unit 23 measures the power value of the first radio signal while switching the directivity of the first receiving antenna 21 and the first transmitting antenna 22. In the indoor part 30, the second control unit 33 measures the power value of the second radio signal while switching the directivity of the second receiving antenna 31 and the second transmitting antenna 32.

[0153] In addition, even when the initial access is established between the terminal 200 and the base station of the communication carrier to which the terminal 200 subscribes during the time TW, and then the terminal 200 ends data communication and there is no response from the terminal 200, the same operations are performed in the outdoor part 20 and the indoor part 30.

[0154] Therefore, the time TW needs to be at least longer than the time for the first power measurement unit 237 and the second power measurement units 337a, 337b, 337c to measure the power value of the radio signal once. The time TW is preferably longer than the time required for initial access between the terminal 200 and the base station of the communication carrier to which the terminal 200 subscribes. For example, the time TW is 1000 ms. In addition, when the time required for reconnection between the terminal 200 and the base station of the communication carrier to which the terminal 200 subscribes is longer than the time related to initial access, the time TW may be set longer than the time required for reconnection.

[0155] When the first control unit 23 waits during the time TW, it determines whether there is communication again from the indoor part 30 side during the time TW (S77). When the first control unit 23 determines that there is communication again from the indoor part 30 side, it returns to S51. On the other hand, when the first control unit 23 determines that there is no communication again from the indoor part 30 side, it returns to S11 in FIG. 6.

[0156] [Operation of the second control unit] Next, the operation of the second control unit 33 will be described. FIG. 8 is a diagram showing an example of the operation flowchart of the second control unit 33. The second control unit 33 associates the power value of the second radio signal with the assigned frequency band FB and the directivity number P in the second power value storage unit 341 and records it in the second measurement table according to the flowchart shown in FIG. 8. Further, the second control unit 33 transmits the assigned frequency band FB associated with the power value of the second radio signal exceeding the threshold value TH to the first control unit 23 according to the flowchart shown in FIG. 8.

[0157] As shown in FIG. 8, the second control unit 33 associates the power value of the second radio signal with the assigned frequency band FB and the directivity number P as described above and records it in the second measurement table (S101). After the second control unit 33 records the power value of the second radio signal, it determines whether a power value exceeding the threshold value TH has been recorded in the second measurement table (S103).

[0158] If the second control unit 33 determines that a power value exceeding the threshold value TH is not recorded in the second measurement table, it determines whether the directivity number P associated with the power value of the second radio signal recorded in S101 is the maximum value among the plurality of directivity numbers P assigned to the plurality of second directivity patterns P2 (S111). If the first control unit 23 determines that the directivity number P is the maximum value, it resets the directivity number P to 11 (S113) and returns to S101. If the second control unit 33 determines that the directivity number P is not the maximum value, it increments the directivity number P (S115) and returns to S101.

[0159] On the other hand, if the second control unit 33 determines that a power value exceeding the threshold value TH is recorded in the second measurement table, it transmits the information of the specific assigned frequency band FB associated with the power value exceeding the threshold value TH to the first control unit 23 (S105). The second control unit 33 acquires the directivity number P that recorded the maximum power value in the specific assigned frequency band from the second measurement table of the second power value storage unit 341 (S107). The second control unit 33 sets the second directivity pattern P2 to which the acquired directivity number P is assigned and changes the directivities of the second receiving antenna 31 and the second transmitting antenna 32 (S107).

[0160] Specifically, the second control unit 33 obtains the maximum power value of a plurality of second radio signals associated with a specific assigned frequency band FB from the second measurement table of the second power value storage unit 341. The second control unit 33 obtains the directivity number P associated with the obtained power value of the second radio signal. The second control unit 33 sets a second directivity control signal including the second directivity pattern P2 to which the obtained directivity number P is assigned, and transmits the second directivity control signal to the second receiving antenna 31 and the second transmitting antenna 32. Thereby, the second control unit 33 changes the directivity of the second receiving antenna 31 and the second transmitting antenna 32.

[0161] During the time TW, the second control unit 33 maintains the directivity of the second receiving antenna 31 and the second transmitting antenna 32, records the maximum value of the power value of the second radio signal (S109), and returns to S103.

[0162] Regarding the threshold TH, for example, when the limit of the reception sensitivity is -83 dBm and there is a gain of 30 dB including the following gains and losses, a power value of -53 dBm is obtained in each of the second power measurement units 337a, 337b, and 337c. In this case, the threshold TH is set to -53 dBm. Note that an LNA (Low Noise Amplifier) is included in the second receiving antenna 31. · Antenna gain · LNA gain · Coupler loss · Mixer conversion gain · Band-pass filter loss

[0163] [Initial access procedure] Next, the initial access procedure in the relay system 1 will be described. FIG. 9 is a diagram showing an example of a sequence of the initial access procedure in the relay system 1. In the example shown in FIG. 9, it is assumed that the terminal 200 performs an initial access with the base station 100b of the communication carrier B to which it subscribes.

[0164] Generally, initial access can be performed even at a low SNR compared to data communication that is performed after initial access is established. For this reason, in the relay device 10, even if the antenna directivity is deviated from the terminal 200 and the base station 100b, initial access may be established. Also, in the relay device 10, the antenna directivity changes every time the power value is measured. For this reason, after a certain period of time has elapsed, the directivities of the first receiving antenna 21 and the first transmitting antenna 22 in the outdoor unit 20 face the direction of the base station 100b. Similarly, after the elapse of the certain period of time, the directivities of the second receiving antenna 31 and the second transmitting antenna 32 in the indoor unit 30 face the direction of the terminal 200. As a result, the terminal 200 can obtain a radio wave intensity sufficient to communicate with the base station 100b. An example of such a process will be described with reference to FIG. 9.

[0165] Note that it is assumed that in the first receiving antenna 21 and the first transmitting antenna 22, the power value of the first radio signal is maximum in the first directivity pattern P1 in which the directivity number P = 4 is assigned in the allocated frequency band FB = B1. Also, it is assumed that in the second receiving antenna 31 and the second transmitting antenna 32, in the allocated frequency band FB = B1, the power value of the second radio signal exceeds the threshold value TH and is maximum in the second directivity pattern P2 in which the directivity number P = 14 is assigned.

[0166] As shown in FIG. 9, in the relay device 10, the first receiving antenna 21 in the outdoor unit 20 receives the notification information (SS / PBCH block) from the base station 100b as the first radio signal in the allocated frequency band FB = B1 in the first directivity pattern P1 with the directivity number P = 2 (S151). The outdoor unit 20 relays the received notification information to the indoor unit 30 (S153). The second transmitting antenna 32 in the indoor unit 30 re-radiates the relayed notification information as the first radio signal in the allocated frequency band FB = B1 in the second directivity pattern P2 with the directivity number P = 13 (S155).

[0167] The second receiving antenna 31 inside the house 30 receives Msg.1 (PRACH: Physical Random Access CHANNEL) from the terminal 200 as a second radio signal in the allocated frequency band FB = B1 with the second directivity pattern P2 having a directivity number P = 13 (S157). The house interior 30 relays the received Msg.1 to the outside of the house 20 (S159). The first transmitting antenna 22 outside the house 20 re-radiates the relayed Msg.1 as a second radio signal in the allocated frequency band FB = B1 with the first directivity pattern P1 having a directivity number P = 3 (S161).

[0168] The first receiving antenna 21 outside the house 20 receives Msg.2 (RA RESPONSE) from the base station 100b as a first radio signal in the allocated frequency band FB = B1 with the first directivity pattern P1 having a directivity number P = 3 (S163). The outside of the house 20 relays the received Msg.2 to the inside of the house 30 (S165). The second transmitting antenna 32 inside the house 30 re-radiates the relayed Msg.2 as a first radio signal in the allocated frequency band FB = B1 with the second directivity pattern P2 having a directivity number P = 14 (S167).

[0169] The second receiving antenna 31 inside the house 30 receives Msg.3 from the terminal 200 as a second radio signal in the allocated frequency band FB = B1 with the second directivity pattern P2 having a directivity number P = 14 (S169). At this time, the second control unit 33 inside the house 30 measures the power value of Msg.3 exceeding the threshold TH (S171) and transmits information on the allocated frequency band FB = B1 to the first control unit 23 outside the house 20 (S173). The second control unit 33 acquires the directivity number P = 14 that recorded the maximum power value in the allocated frequency band FB = B1, sets and maintains the second directivity pattern P2 with the directivity number P = 14 (S175), measures the power value during the time TW, and records the maximum value.

[0170] When the first control unit 23 outside the house 20 receives information on the allocated frequency band FB = B1 from the second control unit 33, it acquires the directivity number P = 4 that recorded the maximum power value in the allocated frequency band FB = B1, sets and maintains the first directivity pattern P1 with the directivity number P = 4 (S177), and waits during the time TW.

[0171] The interior 30 of the house relays the received Msg.3 to the exterior 20 of the house (S179). Note that the process of S179 may be before the process of S173 or simultaneous with the process of S173. The first transmission antenna 22 of the exterior 20 of the house re-radiates the relayed Msg.3 as the second radio signal in the assigned frequency band FB = B1 with the maintained first directivity pattern P1 having the directivity number P = 4 (S181).

[0172] The first receiving antenna 21 of the exterior 20 of the house receives Msg.4 from the base station 100b as the first radio signal in the assigned frequency band FB = B1 with the maintained first directivity pattern P1 having the directivity number P = 4 (S183). The exterior 20 of the house relays the received Msg.4 to the interior 30 of the house (S185). The second transmission antenna 32 of the interior 30 of the house re-radiates the relayed Msg.4 as the first radio signal in the assigned frequency band FB = B1 with the maintained second directivity pattern P2 having the directivity number P = 14 (S187).

[0173] When the terminal 200 receives Msg.4, the initial access between the terminal 200 and the base station 100b is established. Thereafter, the first receiving antenna 21 and the first transmission antenna 22 of the exterior 20 of the house use the first directivity pattern P1 having the directivity number P = 4. Also, the second receiving antenna 31 and the second transmission antenna 32 of the interior 30 of the house use the second directivity pattern P2 having the directivity number P = 14. Thereby, subsequent data communication is performed between the terminal 200 and the base station 100b.

[0174] [Operation and Effect] In this embodiment, the relay device 10 is installed in the installed body 3 and performs wireless relay between the terminal 200 and any one of the base stations 100a, 100b, and 100c that communicate using a predetermined assigned frequency band FB.

[0175] The first receiving antenna 21 is installed outside the object 3 to be installed, and receives the first radio signals radiated from each of the plurality of base stations 100a, 100b, 100c based on the first directivity pattern P1. The first control unit 23 sets each of the plurality of allocated frequency bands FB = A1, B1, C1 used by the plurality of base stations 100a, 100b, 100c as a first measurement frequency band. The first control unit 23 measures the reception power of the first radio signal received by the first receiving antenna 21 for each first measurement frequency band while switching the first directivity pattern P1.

[0176] The second receiving antenna 31 is installed inside the object 3 to be installed, and receives the second radio signal radiated from the terminal 200 based on the second directivity pattern P2. The second control unit 33 sets each of the plurality of allocated frequency bands FB = A1, B1, C1 used by the plurality of base stations 100a, 100b, 100c as a second measurement frequency band. The second control unit 33 measures the reception power of the second radio signal received by the second receiving antenna 31 for each second measurement frequency band while switching the second directivity pattern P2.

[0177] The inter-antenna relay line 40a communicably connects the first receiving antenna 21 and the second transmitting antenna 32. The inter-antenna relay line 40b communicably connects the second receiving antenna 31 and the first transmitting antenna 22. The inter-control unit relay line 40c communicably connects the first control unit 23 and the second control unit 33.

[0178] The first transmitting antenna 22 re-radiates the second radio signal relayed from the second receiving antenna 31 via the inter-antenna relay line 40b based on the first directivity pattern P1. The second transmitting antenna 32 re-radiates the first radio signal relayed from the first receiving antenna 21 via the inter-antenna relay line 40a based on the second directivity pattern P2.

[0179] The first control unit 23 records by associating the received power of the measured first radio signal with the information of the first directivity pattern P1 and the allocated frequency band FB corresponding to the first measurement frequency band. The second control unit 33 records by associating the received power of the measured second radio signal with the information of the second directivity pattern P2 and the allocated frequency band FB corresponding to the second measurement frequency band.

[0180] When the received power of the second radio signal exceeds the threshold value TH, the second control unit 33 transmits, via the control unit inter-relay line 40c, the information of the specific allocated frequency band FB associated with the received power of the second radio signal that exceeds the threshold value TH to the first control unit 23. The second control unit 33 maintains the second directivity pattern P2 associated with the received power of the second radio signal having the maximum value among the received powers of the plurality of second radio signals associated with the specific allocated frequency band FB. The first control unit 23 maintains the first directivity pattern associated with the received power of the first radio signal having the maximum value among the received powers of the plurality of first radio signals associated with the specific allocated frequency band FB upon receiving the information of the specific allocated frequency band FB.

[0181] With such a configuration, the relay device 10 can maintain the first directivity pattern P1 of the first receiving antenna 21 and the first transmitting antenna 22 as the directivity pattern for receiving the first radio signal having the maximum received power among the specific allocated frequency bands. The relay device 10 can maintain the second directivity pattern P2 of the second receiving antenna 31 and the second transmitting antenna 32 as the directivity pattern for receiving the second radio signal having the maximum received power among the specific allocated frequency bands.

[0182] In this way, the relay device 10 can direct the directivities of the first receiving antenna 21 and the first transmitting antenna 22 in the direction where the base station to which the terminal 200 belongs is installed by using the information of the specific allocated frequency band transmitted and received by the control unit inter-communication. Similarly, the relay device 10 can direct the directivities of the second receiving antenna 31 and the second transmitting antenna 32 in the direction where the terminal 200 is located by using the information of the specific allocated frequency band.

[0183] Therefore, without using the "regenerative" relay technology, the relay device 10 can reliably relay radio signals between the terminal 200 and any one of the base stations 100a, 100b, and 100c by using a specific assigned frequency band allocated to a specific telecommunications carrier. Thus, the relay device 10 can reliably provide the desired service to the terminal 200 while suppressing an increase in cost in relaying radio signals.

[0184] Also, with such a configuration, the relay device 10 can grasp the directions in which the base stations of the respective telecommunications carriers are installed by measuring and recording the received power of radio signals for each assigned frequency band FB allocated to each of the telecommunications carriers A, B, and C while switching the antenna directivity. Also, the telecommunications carrier to which the terminal 200 subscribes can be estimated by measuring and recording the received power of radio signals for each assigned frequency band allocated to each of the telecommunications carriers A, B, and C.

[0185] Generally, radio waves in the millimeter wave band have characteristics such as large space attenuation, high directivity, and being easily affected by shielding and absorption by walls and trees compared to radio waves in the microwave band. For this reason, in order to relay radio signals in the millimeter wave band using a relay device outdoors and indoors, it is necessary to direct the directivity of the outdoor antenna in the direction where the base station is installed.

[0186] Even in such wireless communication where it is necessary to direct the antenna directivity in the direction where the base station is installed, wireless relaying between the base station and the terminal can be performed by one relay device 10 without installing relay devices or directional antennas for each telecommunications carrier.

[0187] In this way, by measuring the received power of radio signals in the assigned frequency band FB of each telecommunications carrier by the relay device 10, the direction of the base station of each telecommunications carrier and the telecommunications carrier to which the terminal 200 subscribes can be estimated. For this reason, since it is not necessary to demodulate and remodulate data from radio signals in the relay device 10, the cost of manufacturing the relay device 10 can be suppressed.

[0188] In this embodiment, the first control unit 23 includes a first band-pass filter 235 and a first power measurement unit 237. When the frequency of the first radio signal is included in the first measurement frequency band, the first band-pass filter 235 allows the first radio signal to pass through without attenuation. When the frequency of the first radio signal is not included in the first measurement frequency band, the first band-pass filter 235 attenuates the first radio signal. The first power measurement unit 237 measures the received power of the first radio signal at the subsequent stage of the first band-pass filter 235.

[0189] The second control unit 33 includes second band-pass filters 335a, 335b, 335c and second power measurement units 337a, 337b, 337c. Each of the second band-pass filters 335a, 335b, 335c allows the second radio signal to pass through without attenuation when the frequency of the second radio signal is included in the second measurement frequency band. Each of the second band-pass filters 335a, 335b, 335c attenuates the second radio signal when the frequency of the second radio signal is not included in the second measurement frequency band. Each of the second power measurement units 337a, 337b, 337c measures the received power of the second radio signal at the subsequent stage of each of the second band-pass filters 335a, 335b, 335c.

[0190] With such a configuration, in the relay device 10, it is not necessary to perform demodulation and remodulation of data from the radio signal, so the cost of manufacturing the relay device 10 can be suppressed.

[0191] In this embodiment, the first control unit 23 further includes a first mixer 231 that performs frequency down-conversion on the first radio signal at the previous stage of the first band-pass filter 235. The second control unit 33 further includes a second mixer 331 that performs frequency down-conversion on the second radio signal at the previous stage of the second band-pass filters 335a, 335b, 335c.

[0192] With such a configuration, the ratio bandwidths of the first band-pass filter 235 and the second band-pass filters 335a, 335b, 335c used to separate the radio signals in the allocated frequency band FB = A1, B1, C1 can be increased.

[0193] For example, when separating a radio signal with a bandwidth of 400 MHz in the 28 GHz band, the ratio bandwidth is about 1.4%, and it is difficult to separate with a general filter. In this case, it is difficult to separate the signals in adjacent frequency bands from each other. Therefore, when measuring the power value of one radio signal in an adjacent allocated frequency band, the other radio signal cannot be sufficiently attenuated, and the power value of one radio signal is measured in a state where the other radio signal is mixed in. For this reason, the directions of the base stations of each of the communication carriers A, B, and C cannot be estimated from the power values of the radio signals.

[0194] On the other hand, for example, if the signal in the 28 GHz band is down-converted to the 2 GHz band, the ratio bandwidth of 400 MHz becomes 20%, and it is possible to easily extract only the radio signal in the desired allocated frequency band FB by the band-pass filter. Therefore, by using the relay device 10, the reception powers of the first radio signal and the second radio signal can be accurately measured.

[0195] In the present embodiment, the pass bandwidth of the first band-pass filter 235 is narrower than the bandwidth of the first measurement frequency band. The pass bandwidth of each of the second band-pass filters 335a, 335b, 335c is narrower than the bandwidth of the second measurement frequency band.

[0196] With such a configuration, the pass bandwidth of the band-pass filter can be narrowed. Therefore, when measuring the power value of one radio signal in an adjacent allocated frequency band, the other radio signal can be sufficiently attenuated, and only the power value of one radio signal can be measured. Therefore, the directions in which the base stations of each of the communication carriers A, B, and C are installed can be accurately estimated from the power values of the radio signals.

[0197] In this embodiment, since it is sufficient to obtain a power value proportional to the received power of each of the radio signals in the assigned frequency bands FB = A1, B1, C1, it is not necessary to perform demodulation. Also, since the power of the radio signals is evenly distributed across the entire frequency band, it is not necessary to cut out each entire assigned frequency band FB = A1, B1, C1. For this reason, the passband width of the band-pass filter can be narrowed.

[0198] In this embodiment, while switching the first directivity pattern P1, the first control unit 23 associates and records the average value or the maximum value of the received power of the first radio signal measured within a certain period for each first measurement frequency band with the information of the first directivity pattern P1 and the assigned frequency band FB corresponding to the first measurement frequency band. While switching the second directivity pattern P2, the second control unit 33 associates and records the average value or the maximum value of the received power of the second radio signal measured within a certain period for each second measurement frequency band with the information of the second directivity pattern P2 and the assigned frequency band FB corresponding to the second measurement frequency band.

[0199] With such a configuration, when the first radio signal is intermittently radiated from each of the base stations 100a, 100b, 100c, since the timing at which the first radio signal is radiated and the timing at which the first control unit 23 performs power measurement are misaligned, it is possible to avoid a state where the first control unit 23 cannot measure the received power of the first radio signal.

[0200] Similarly, when the second radio signal is intermittently radiated from the terminal 200, since the timing at which the second radio signal is radiated and the timing at which the second control unit 33 performs power measurement are misaligned, it is possible to avoid a state where the second control unit 33 cannot measure the received power of the second radio signal.

[0201] In this embodiment, the first control unit 23 maintains the first directivity pattern P1 for a time period TW in response to receiving information on a specific assigned frequency band FB. The second control unit 33 maintains the second directivity pattern P2 for a time period TW in response to transmitting information on a specific assigned frequency band FB. The time period TW is longer than the time required for the terminal 200 to make an initial access to the base station of the communication carrier to which the terminal 200 subscribes, or the time required for the terminal 200 to reconnect to the base station of the communication carrier to which the terminal 200 subscribes.

[0202] With such a configuration, between the terminal 200 and the base station of the communication carrier to which the terminal 200 subscribes, it is possible to avoid the directivity directions of the first receiving antenna 21 and the first transmitting antenna 22 from deviating from the base station before the initial access procedure or the reconnection procedure is completed. Similarly, between the terminal 200 and the base station of the communication carrier to which the terminal 200 subscribes, it is possible to avoid the directivity directions of the first receiving antenna 21 and the first transmitting antenna 22 from deviating from the terminal 200 before the initial access procedure or the reconnection procedure is completed. For this reason, the initial access procedure or the reconnection procedure can be stably performed.

[0203] [Modification Example] In the above-described embodiment, the object 3 to be installed was a fixed object such as a building, but it is not limited thereto. The object 3 to be installed may be a moving object such as a vehicle.

[0204] FIG. 10 is an overall schematic configuration diagram of the relay system 1a. As shown in FIG. 10, the relay system 1a includes a vehicle 5, base stations 100a, 100b, 100c, a terminal 200, and a relay device 300.

[0205] The vehicle 5 has a vehicle body 5a. The interior of the vehicle 5 is surrounded by the vehicle body 5a and is referred to as the passenger compartment of the vehicle 5. The exterior of the vehicle 5 is referred to as the outside of the vehicle 5.

[0206] The terminal 200 is located inside the passenger compartment of the vehicle 5. Therefore, between the base stations 100a, 100b, 100c and the terminal 200, there is the vehicle body 5a of the vehicle 5. Since the radio waves are shielded by the vehicle body 5a, the terminal 200 cannot directly perform wireless communication with the base stations of the communication carrier it subscribes to.

[0207] The relay device 300 is installed in the vehicle 5 and performs wireless relaying between any one of the base stations 100a, 100b, 100c and the terminal 200. In the relay device 300, the part corresponding to the outdoor part 20 of the relay device 10 is installed on the outer roof of the vehicle 5, and the part corresponding to the indoor part 30 of the relay device 10 is set on the inner roof of the vehicle 5. Thus, in the relay device 300, the part corresponding to the outdoor part 20 of the relay device 10 and the part corresponding to the indoor part 30 of the relay device 10 are close to each other in physical distance. For this reason, in the relay device 300, the part corresponding to the first control unit 23 of the outdoor part 20 is integrated with the part corresponding to the second control unit 33 of the indoor part 30.

[0208] Note that in the relay device 300, the part corresponding to the outdoor part 20 of the relay device 10 may be installed outside across the window of the vehicle 5, and the part corresponding to the indoor part 30 of the relay device 10 may be set inside across the window of the vehicle 5. Even in this case, in the relay device 300, the part corresponding to the first control unit 23 of the outdoor part 20 can be integrated with the part corresponding to the second control unit 33 of the indoor part 30.

[0209] In this modification example, the number of the first directivity patterns P1 of each of the first receiving antenna 311 and the first transmitting antenna 312 is four. For the four first directivity patterns P1, directivity numbers P = 1, 2, 3, 4 are assigned from above in the plane perpendicular to the ground (elevation angle direction).

[0210] On the other hand, since the interior of the vehicle 5 is a narrow space, the number of the second directivity patterns P2 of each of the second receiving antenna 314 and the second transmitting antenna 315 is one. The directivity number P = 21 is assigned to the second directivity pattern P2. Thus, when the number of the second directivity patterns P2 is one, the operation of switching the directivity patterns can be omitted. Note that each of the second receiving antenna 314 and the second transmitting antenna 315 may be an omnidirectional antenna.

[0211] FIG. 11 is a block configuration diagram of the relay device 300. As shown in FIG. 11, the relay device 300 includes a first receiving antenna 311, a first transmitting antenna 312, a control unit 313, a second receiving antenna 314, a second transmitting antenna 315, a first coupler 316, a second coupler 317, a first relay line 319, and a second relay line 321.

[0212] The first receiving antenna 311 and the first transmitting antenna 312 are arranged outside the vehicle 5. The second receiving antenna 314 and the second transmitting antenna 315 are arranged inside the vehicle 5.

[0213] The first coupler 316 branches the first radio signal received by the first receiving antenna 311 and inputs the first radio signal to the control unit 313 and the second transmitting antenna 315. The second coupler 317 branches the first radio signal received by the second receiving antenna 314 and inputs the first radio signal to the control unit 313 and the first transmitting antenna 312.

[0214] The control unit 313 is connected to the output side of the first receiving antenna 311 via the first coupler 316. The control unit 313 is directly connected to the input sides of the first receiving antenna 311 and the first transmitting antenna 312. The control unit 313 is connected to the output side of the second receiving antenna 314 via the second coupler 317. The control unit 313 is directly connected to the input sides of the second receiving antenna 314 and the second transmitting antenna 315.

[0215] With such a configuration, the control unit 313 has the functions of the first control unit 23 and the second control unit 33 of the relay device 10. Note that in the relay device 300, the control unit inter-relay line 40c that communicably connects the first control unit 23 and the second control unit 33 in the relay device 10 is omitted.

[0216] The first relay line 319 communicably connects the first receiving antenna 311 and the second transmitting antenna 315. The second relay line 321 communicably connects the second receiving antenna 314 and the first transmitting antenna 312.

[0217] In this modified example, as described above, the first control unit 23 and the second control unit 33 in the relay device 10 are integrated, and the control unit inter-relay line 40c in the relay device 10 is omitted.

[0218] With such a configuration, for example, when the physical distance between the first control unit 23 and the second control unit 33 is short, the control unit inter-relay line 40c that communicably connects the first control unit 23 and the second control unit 33 can be omitted, and the cost of manufacturing the relay device 300 can be suppressed.

[0219] In the above-described embodiment, each of the first receiving antenna 21, the first transmitting antenna 22, the second receiving antenna 31, and the second transmitting antenna 32 was a steerable antenna, but it is not limited thereto. For example, each of the first receiving antenna 21, the first transmitting antenna 22, the second receiving antenna 31, and the second transmitting antenna 32 may be an array antenna. In this case, each of the first control unit 23 and the second control unit 33 changes the directivity of the antenna by adjusting the power and phase supplied to each antenna.

[0220] Also, the functions of each of the first receiving antenna 21, the first transmitting antenna 22, the second receiving antenna 31, and the second transmitting antenna 32 may be realized by switching a plurality of directional antennas attached in different directions.

[0221] In the above-described embodiment, the control unit intermediate relay line 40c is provided separately from the antenna intermediate relay lines 40a and 40b, but is not limited thereto. For example, since the control unit intermediate signal transmitted via the control unit intermediate relay line 40c has a different band from the first radio signal and the second radio signal, the control unit intermediate relay line 40c may be shared with at least one of the antenna intermediate relay line 40a and the antenna intermediate relay line 40b.

[0222] For example, in control unit-to-control unit communication, step-synchronous serial communication is performed with a baseband 10 Mbps signal, and in antenna-to-antenna relay, communication is performed with a radio signal in the 28 GHz band. Even if these signals are transmitted through the same coaxial cable, they can be easily separated by a filter on the receiving side.

[0223] In the above-described embodiment, the number of terminals 200 is one, but is not limited thereto. For example, when a plurality of terminals 200 belonging to different communication carriers are located indoors of the object 3 to be installed, one terminal 200 can communicate with the base station of the communication carrier to which the terminal 200 belongs, in the order of arrival.

[0224] Note that the functions of the first power measurement unit 237, the first power value storage unit 241, the frequency setting unit 243, and the first directivity control unit 245 of the first control unit 23 in the above-described embodiment are realized by any combination of at least one of hardware and software. Also, the functions of the second power measurement units 337a, 337b, 337c, the second power value storage unit 341, and the second directivity control unit 343 of the second control unit 33 in the above-described embodiment are realized by any combination of at least one of hardware and software.

[0225] For example, each of these functions is realized by a processor performing calculations in accordance with a predetermined software (program) and controlling the reading and writing of data in the memory and storage.

[0226] Note that at least two or more of these modification examples may be combined and applied to the above-described embodiment.

[0227] The above describes the present embodiment, but the present embodiment is not limited thereto, and various modifications are possible within the scope of the gist of the present embodiment.

Explanation of Reference Numerals

[0228] 3 Installed Object 10 Relay Device 21 First Reception Antenna 22 First Transmission Antenna 23 First Control Unit 31 Second Reception Antenna 32 Second Transmission Antenna 33 Second Control Unit 40a, 40b Intermediate Relay Line between Antennas 40c Intermediate Relay Line between Control Units 100a, 100b, 100c Base Stations 200 Terminal FB Assigned Frequency Band P1 First Directivity Pattern P2 Second Directivity Pattern

Claims

1. A relay device that performs wireless relaying between a base station and a terminal, which are installed on an object to be installed and communicate using a predetermined allocated frequency band, a first antenna that is installed outside the object to be installed and receives a first radio signal radiated from each of a plurality of base stations based on a first directivity pattern; a first control unit that sets each of a plurality of allocated frequency bands used by the plurality of base stations as a first measurement frequency band, and measures the reception power of the first radio signal received by the first antenna for each of the first measurement frequency bands while switching the first directivity pattern; a second antenna that is installed inside the object to be installed and receives a second radio signal radiated from the terminal based on a second directivity pattern; a second control unit that sets each of the plurality of allocated frequency bands used by the plurality of base stations as a second measurement frequency band, and measures the reception power of the second radio signal received by the second antenna for each of the second measurement frequency bands while switching the second directivity pattern; a first relay line that communicably connects the first antenna and the second antenna; a second relay line that communicably connects the first control unit and the second control unit; and includes the first antenna re-radiates the second radio signal relayed from the second antenna via the first relay line based on the first directivity pattern, the second antenna re-radiates the first radio signal relayed from the first antenna via the first relay line based on the second directivity pattern, the first control unit records the measured reception power of the first radio signal in association with the information of the first directivity pattern and the allocated frequency band corresponding to the first measurement frequency band, the second control unit records the measured reception power of the second radio signal in association with the information of the second directivity pattern and the allocated frequency band corresponding to the second measurement frequency band, when the reception power of the second radio signal exceeds a threshold, the second control unit transmits, via the second relay line, information on a specific allocated frequency band associated with the reception power of the second radio signal that exceeds the threshold to the first control unit, the second control unit maintains the second directivity pattern associated with the reception power of the second radio signal having the maximum value among the reception powers of a plurality of second radio signals associated with the specific allocated frequency band The first control unit is a relay device that maintains the first directivity pattern associated with the reception power of the first radio signal having the maximum value among the reception powers of a plurality of first radio signals associated with the specific assigned frequency band upon reception of the information on the specific assigned frequency band.

2. The first control unit includes a first band-pass filter that passes the first radio signal without attenuation when the frequency of the first radio signal is included in the first measurement frequency band, and attenuates the first radio signal when the frequency of the first radio signal is not included in the first measurement frequency band; and a first power measurement unit that measures the reception power of the first radio signal after the first band-pass filter. The relay device according to claim 1, comprising: The second control unit includes a second band-pass filter that passes the second radio signal without attenuation when the frequency of the second radio signal is included in the second measurement frequency band, and attenuates the second radio signal when the frequency of the second radio signal is not included in the second measurement frequency band; and a second power measurement unit that measures the reception power of the second radio signal after the second band-pass filter. The relay device according to claim 1, comprising:

3. The first control unit further includes a first mixer that performs frequency down-conversion on the first radio signal in front of the first band-pass filter; The relay device according to claim 2, wherein the second control unit further includes a second mixer that performs frequency down-conversion on the second radio signal in front of the second band-pass filter.

4. The pass-band width of the first band-pass filter is narrower than the band width of the first measurement frequency band; when the frequency of the first radio signal frequency-converted by the first mixer is included in the pass band of the first band-pass filter, the first band-pass filter passes the first radio signal without attenuation; The pass-band width of the second band-pass filter is narrower than the band width of the second measurement frequency band; when the frequency of the second radio signal frequency-converted by the second mixer is included in the pass band of the second band-pass filter, the second band-pass filter passes the second radio signal without attenuation. The relay device according to claim 3.

5. While switching the first directivity pattern, the first control unit associates and records, for each first measurement frequency band, the average value or the maximum value of the reception power of the first radio signal measured within a certain period with the information of the first directivity pattern and the assigned frequency band corresponding to the first measurement frequency band. The relay device according to claim 1, wherein the second control unit associates and records, for each second measurement frequency band, the average value or the maximum value of the reception power of the second radio signal measured within a certain period with the information of the second directivity pattern and the assigned frequency band corresponding to the second measurement frequency band while switching the second directivity pattern.

6. When receiving the information of the specific assigned frequency band, the first control unit maintains the first directivity pattern during the standby time. When transmitting the information of the specific assigned frequency band, the second control unit maintains the second directivity pattern during the standby time. The relay device according to claim 1, wherein the standby time is longer than the time required for the terminal to perform an initial access to the base station or the time required for the terminal to reconnect to the base station.

7. A relay device that performs wireless relaying between a base station and a terminal that are installed on an object to be installed and communicate using a predetermined assigned frequency band, a first antenna that is installed outside the object to be installed and receives a first radio signal radiated from each of a plurality of base stations based on a first directivity pattern; a second antenna that is installed inside the object to be installed and receives a second radio signal radiated from the terminal based on a second directivity pattern; a relay line that communicably connects the first antenna and the second antenna; a control unit connected to the first antenna and the second antenna; comprising: The first antenna re-radiates the second radio signal relayed from the second antenna via the relay line based on the first directivity pattern. The second antenna re-radiates the first radio signal relayed from the first antenna via the relay line based on the second directivity pattern. The control unit sets each of the plurality of assigned frequency bands used by the plurality of base stations as a first measurement frequency band, and measures the reception power of the first radio signal received by the first antenna for each first measurement frequency band while switching the first directivity pattern. The control unit records by associating the measured reception power of the first radio signal with the information on the first directivity pattern and the assigned frequency band corresponding to the first measurement frequency band. The control unit sets each of the plurality of assigned frequency bands used by the plurality of base stations as a second measurement frequency band, and measures the reception power of the second radio signal received by the second antenna for each of the second measurement frequency bands while switching the second directivity pattern. The control unit records by associating the measured reception power of the second radio signal with the information on the second directivity pattern and the assigned frequency band corresponding to the second measurement frequency band. When the reception power of the second radio signal exceeds a threshold value, the control unit maintains the first directivity pattern associated with the reception power of the first radio signal having the maximum value among the reception powers of the plurality of first radio signals associated with the specific assigned frequency band associated with the reception power of the second radio signal that exceeds the threshold value. A relay device that, when the reception power of the second radio signal exceeds a threshold value, maintains the second directivity pattern associated with the reception power of the second radio signal having the maximum value among the reception powers of the plurality of second radio signals associated with the specific assigned frequency band associated with the reception power of the second radio signal that exceeds the threshold value.

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