JP5565287B2 - Base station apparatus and communication method - Google Patents

Description

  The present invention relates to a base station apparatus and a communication method using the base station apparatus.

  In recent years, cellular phones have become widespread due to the expansion of service areas by each mobile communication carrier. Along with the popularization of mobile phones, the volume of data transmitted and received by communication is also increasing, and it is required to increase the amount of data (throughput) that can be communicated within a unit time. In the case of wireless communication, a position with good communication quality and a bad position may occur due to the influence of walls and obstacles. If the communication quality is poor, the throughput is reduced, so that a user in a position with poor communication quality may start communication after moving to a position with good communication quality. Since such a situation is inconvenient for the user, the mobile communication carrier installs a base station at a position where the communication quality is bad so as to eliminate the area where the communication quality is bad. For example, in a room of a building as shown in FIG. 1A, the communication quality in the area 3 (3a to 3f) is different due to the influence of the wall 1 (1a to 1c) and the obstacle 2 (2a to 2f). Suppose that it is worse than the area. In this case, the mobile communication carrier installs base stations 4 (4a to 4k) in area 3, as shown in FIG. Here, an area indicated by a dotted line in FIG. 1B is an area where the communication quality is improved by the base station 4. As shown in FIG. 1, the mobile communication service provider improves the communication quality in the area 3 by installing the base station 4.

  As a related technique, a system using a mobile base station moving in the direction of traffic flow moving along a road has been proposed. In this system, a large number of mobile base stations are installed on a closed loop, and the mobile base stations move with traffic flow on the road.

Special Table 2000-516047

  In order to ensure convenience for users, it is required to eliminate areas with poor communication quality, but when installing base stations in areas with poor communication quality, the number of installed base stations increases. Processing in a host device that accommodates the base station may be complicated. There is also a problem that capital investment increases due to the large number of installed base stations.

  An object of the present invention is to provide a method for improving the communication quality of a terminal used by a user.

  A base station apparatus according to an embodiment is a base station apparatus that transmits and receives signals to and from a terminal, and includes a reception unit, a transmission unit, a signal transmission request unit, and a moving unit. The receiving unit receives a signal transmitted from the terminal. The transmission unit transmits a signal directed to the terminal. When the signal transmission request unit receives the connection request signal transmitted from the terminal, the signal transmission request unit responds to the connection request signal with power lower than the transmission power of the notification signal that notifies the terminal of information used to generate the connection request signal. The transmission unit is requested to transmit a connection response signal to be transmitted. The moving unit moves the base station apparatus from receiving the connection request signal to receiving a connection message from a terminal permitted to connect by the connection response signal.

  The communication quality of the terminal used by the user can be improved.

It is a figure which shows the example of the improvement method of communication quality. It is a figure which shows the example of the communication quality improvement method which concerns on embodiment. It is a figure explaining the example of the installation method of a base station. It is a figure which shows the example of a structure of a base station. It is a sequence diagram explaining the example of the signal transmitted / received in 1st Embodiment. It is a flowchart explaining the example of operation | movement of the base station which concerns on 1st Embodiment. It is a figure which shows the example of the table which recorded the received power of the terminal. It is a sequence diagram explaining the example of operation | movement of the base station during communicating with a terminal. An example of a method for restricting the use of a terminal in a partial area of a building is shown. It is a figure explaining the installation example of a base station and a macrocell base station. It is a figure which shows the example of a structure of the base station which concerns on 2nd Embodiment. It is a flowchart which shows the example of operation | movement of the base station which concerns on 2nd Embodiment.

  FIG. 2 is a diagram illustrating an example of a communication quality improving method according to the embodiment. In the example shown in FIG. 2, a guide unit is installed on the ceiling, the back side of the ceiling, the floor, and the like of the room including the wall 1 and the obstacle 2. The base station 20 moves in the room along the guide unit. Here, although the guide part includes any one that forms a path along which the base station 20 moves, such as the rail 10 and the cable, the following description will be made on the case where the guide part is the rail 10.

  The base station 20 transmits a notification signal to terminals in the area where the rail 10 is installed. At this time, the transmission power of the notification signal is assumed to be an intensity at which a terminal located in the area where the rail 10 is installed can receive the notification signal. The terminal that has received the broadcast signal transmits a connection request signal to the base station 20. The base station 20 receives the connection request signal.

  When receiving the connection request signal, the base station 20 transmits a connection response signal in response to the connection request signal to the terminal that permits the connection. At this time, the base station 20 makes the transmission power of the connection response signal smaller than the transmission power of the broadcast signal so that terminals located outside the cell 60 cannot receive the connection response signal. Furthermore, the base station 20 starts moving along the rail 10 when receiving the connection request signal. As the base station 20 moves, the position of the cell 60 also moves along the rail 10. The base station 20 repeats transmission of the connection response signal while moving along the rail 10.

  When the terminal to which the base station 20 permits connection enters the cell 60 as the base station 20 moves, the terminal receives a connection response signal from the base station 20. Then, the terminal transmits a connection message toward the base station 20. When receiving the connection message, the base station 20 recognizes that the terminal permitted to connect is in the cell 60. Thus, the base station 20 stops moving and establishes a connection with the terminal by transmitting a signal in response to the connection message to the terminal.

  In this way, the base station 20 that forms the cell 60 that is smaller than the size of the room moves to a position where a signal can be transmitted to the terminal, whereby the base station 20 improves communication quality around the terminal. be able to. Therefore, communication at a high data rate can be provided to the user of the terminal, and throughput can be improved. Furthermore, since the base station 20 can move in the area where the rail 10 is installed, the base station 4 must be installed in all the areas 3 having poor communication quality as shown in FIG. However, the communication quality of the terminal located near the place where the rail 10 is installed can be improved.

<Device configuration>
The size of the cell 60 formed by the base station 20 is assumed to be smaller than the range where the rail 10 is installed. Although the size of the cell 60 is arbitrarily set according to the implementation, it can be set to the same size as that useful for communication between one terminal and the base station 20, for example. In the following description, a case where the radius of the cell 60 formed by the base station 20 is about 1 meter to several meters will be described. In addition, the notification signal transmitted by the base station 20 is received by a terminal located at an arbitrary position in an area that may be included in the cell 60 as the base station 20 moves. For example, it is assumed that a terminal in an area where the rail 10 is installed can receive a notification signal transmitted from the base station 20. Therefore, for example, when the rail 10 is installed over the entire floor of the building, the base station 20 can transmit a notification signal to the entire floor of the building.

  FIG. 3 is a diagram illustrating an example of an installation method of the base station 20. The base station 20 is installed so that it can move along the rail 10. As will be described later, the base station 20 includes a motor and moves on the rail 10. In addition, FIG. 3 is an example and the installation range and installation shape of the rail 10 are arbitrarily changed. The base station 20 is connected to the core network 11 using backhaul connection. That is, the core network 11 and the base station 20 are connected by the connection cable 13 (13a, 13b). Here, the connection cable 13 is arbitrarily selected from cables that can be used for backhaul connection, such as an optical cable and an Ethernet cable. Further, a backhaul relay unit 12 is installed between the core network 11 and the base station 20 as appropriate. When the backhaul relay unit 12 is installed, the core network 11 transmits data to the base station 20 via the backhaul relay unit 12. The base station 20 also transmits data to the core network 11 via the backhaul relay unit 12.

  FIG. 4 is a diagram illustrating an example of the configuration of the base station 20. The base station 20 includes a receiving unit 21, a transmitting unit 22, a moving unit 23, a storage unit 24, and a control unit 30. The control unit 30 includes a backhaul interface unit 31, a communication control unit 32, a notification signal control unit 33, a signal processing unit 34, a signal transmission request unit 35, a movement instruction unit 36, a timer 37, and a communication monitoring unit 40. The communication monitoring unit 40 further includes a terminal communication monitoring unit 41 and a comparison unit 42.

  The receiving unit 21 receives signals and data transmitted from the terminal to the base station 20 via an antenna (not shown), and performs processing such as demodulation. The receiving unit 21 outputs the received data to the control unit 30. The transmission unit 22 modulates data input from the control unit 30 and transmits the modulated data to the terminal via the antenna. The transmission unit 22 transmits the data input from the control unit 30 with the transmission power notified from the notification signal control unit 33, the signal processing unit 34, and the like. The moving unit 23 includes a motor, and moves the base station 20 along the rail 10 by driving the motor in response to a request from the movement instruction unit 36. Any known method is used as a motor control method.

  The storage unit 24 stores programs, data, and the like used when the control unit 30 operates. Further, the storage unit 24 appropriately stores data included in the control signal received from the terminal by the base station 20. The storage unit 24 also stores data transmitted from the core network 11 to the base station 20 as appropriate. The timer 37 notifies the time information to the signal processing unit 34, the terminal communication monitoring unit 41, and the like.

  The base station 20 communicates with a communication device included in the core network 11 or a communication device connected via the core network 11 via the backhaul interface unit 31. The communication control unit 32 performs control for the base station 20 to communicate with the terminal after the connection between the terminal and the base station 20 is established. In addition, the communication control unit 32 monitors operations of the reception unit 21, the transmission unit 22, the movement unit 23, the storage unit 24, and the like. Further, the communication control unit 32 also monitors the backhaul interface unit 31, the notification signal control unit 33, the signal processing unit 34, the signal transmission request unit 35, the movement instruction unit 36, the timer 37, and the communication monitoring unit 40. ,Control.

  The notification signal control unit 33 controls transmission of the notification signal. The notification signal control unit 33 generates a notification signal and determines transmission power for transmitting the notification signal. The notification signal control unit 33 outputs the notification signal to the transmission unit 22 and notifies the transmission unit 22 of the transmission power of the notification signal.

  The signal processing unit 34 processes data included in the connection request signal and the connection message. The signal processing unit 34 receives the connection request signal and acquires the identifier of the terminal that is permitted to connect. When receiving the connection request signal, the signal processing unit 34 generates a connection response signal and outputs the connection response signal to the transmission unit 22. At this time, the signal processing unit 34 also notifies the transmission unit 22 of the power for transmitting the connection response signal. When there is another cell that is adjacent to or overlaps with the cell 60 of the base station 20, the connection request signal received by the base station 20 from the terminal that has been handed over from the base station forming the other cell to the base station 20 is also available. The signal processing unit 34 processes.

  The connection request signal may be described as “preamble” or “call connection request signal”. The connection response signal may be described as, for example, a random access response. Further, the connection message may be, for example, an RRC connection request.

  The signal transmission request unit 35 requests the transmission unit 22 to transmit the connection response signal when the base station 20 does not receive the connection message within a certain time after the connection response signal is transmitted. In response to a request from the signal transmission request unit 35, the transmission unit 22 repeats transmission of a connection response signal toward the terminal at regular time intervals.

  When the base station 20 receives the connection request signal, the movement instruction unit 36 instructs the movement unit 23 to start moving along the rail 10. In addition, the movement instructing unit 36 can also give an instruction of the moving direction to the moving unit 23 as will be described later. When the base station 20 receives the connection message, the movement instruction unit 36 requests the movement unit 23 to stop moving.

  The terminal communication monitoring unit 41 acquires information included in a signal transmitted from the terminal after communication between the terminal and the base station 20 is established. For example, the terminal communication monitoring unit 41 acquires the received power of the terminal from the received power notification message sent from the terminal. Further, the terminal communication monitoring unit 41 stores the acquired received power in the storage unit 24 in association with the time when the received power notification message is received. The received power notification message may be a measurement report, for example. The comparison unit 42 compares the received power notified from the terminal with the threshold Th. Further, the comparison unit 42 compares the received power notified from the terminal with the received power before the movement of the moving unit 23 is resumed. The operation of the comparison unit 42 will be described in detail later.

  The base station 20 includes an RF circuit, a memory, and a CPU. The memory operates as the storage unit 24. The CPU operates as the control unit 30 by executing a program stored in the storage unit 24. The receiving unit 21 and the transmitting unit 22 include an RF circuit. The base station 20 includes a drive device that drives the base station 20, such as a motor, and the drive device operates as the moving unit 23.

<First Embodiment>
FIG. 5 is a sequence diagram illustrating an example of signals transmitted and received in the first embodiment.
(1) The notification signal control unit 33 transmits a notification signal to a terminal located in the area where the rail 10 is installed via the transmission unit 22. At this time, the base station 20 is assumed to be stopped at a certain position. When the terminal receives the broadcast signal, the terminal acquires information used to request connection to the base station 20.

(2) A user of a terminal located in an area where the rail 10 is installed performs a call operation.
(3) The terminal generates a connection request signal using information acquired from the broadcast signal and transmits the connection request signal to the base station 20.

  (4) When receiving the connection request signal via the receiving unit 21, the signal processing unit 34 notifies the movement instruction unit 36 that the connection request signal has been received. The movement instructing unit 36 instructs the moving unit 23 to start moving. The base station 20 moves along the rail 10 when the moving unit 23 operates in accordance with an instruction from the movement instructing unit 36.

  Furthermore, the signal processing unit 34 notifies the notification signal control unit 33 that the connection request signal has been received. When receiving the notification from the signal processing unit 34, the notification signal control unit 33 stops outputting the notification signal. Accordingly, the base station 20 does not establish a connection with any terminal other than the terminal that has transmitted the connection request signal in the procedure (3). The signal processing unit 34 acquires information included in the connection request signal and acquires a terminal identifier. The signal processing unit 34 determines whether to permit connection to the terminal. In the following description, it is assumed that the base station 20 permits connection to the terminal.

  (5a) The signal processing unit 34 generates a connection response signal including an identifier of a terminal that permits connection. The signal processing unit 34 outputs the generated connection response signal to the transmission unit 22 and notifies the transmission unit 22 of the transmission power of the connection response signal. Note that the signal processing unit 34 stores the value of the transmission power of the connection response signal in advance. In addition, when the transmission power of the connection response signal is stored in the storage unit 24, the signal processing unit 34 can also acquire the value of the transmission power of the connection response signal from the storage unit 24. The transmission unit 22 transmits the input connection response signal with the transmission power notified from the signal processing unit 34. The range in which the connection response signal is transmitted is within the range of the cell 60 shown in FIG. It is assumed that the connection response signal transmitted in the procedure (5a) has not reached the terminal.

  (5b) When the connection response signal is transmitted, the signal transmission request unit 35 sets the timer 37 at a predetermined time and waits until a connection message is transmitted from the terminal. Here, it is assumed that the connection message has not been received before the timer 37 expires. In this case, the signal transmission request unit 35 determines that the connection response signal has not been received by the terminal. Therefore, the transmitter 22 is requested to transmit a connection response signal. At this time, the signal transmission request unit 35 can output a connection response signal to the transmission unit 22 to notify the transmission power of the connection response signal. In this case, the signal transmission request unit 35 is notified of the connection response signal and the transmission power of the connection response signal from the signal processing unit 34 when the connection response signal is transmitted in the procedure (5a).

  (5c) If the connection message cannot be received within a certain time after the connection response signal is transmitted in step (5b), the base station 20 transmits the connection response signal to the terminal again as in step (5b). To do. Since the base station 20 has moved since the procedure (4), the range in which the connection response signal is transmitted differs in the procedures (5a), (5b), and (5c). Until the connection message is received, as described in the procedures (5a) to (5c), the base station 20 transmits a connection response signal to the terminal while moving along the rail 10. Therefore, as the base station 20 moves, the position of the cell 60 also moves along the rail 10.

  (6) When the terminal enters the cell 60, the terminal receives a connection response signal. When receiving the connection response signal, the terminal transmits a connection message to the base station 20 in response to the connection response signal. Here, an RRC connection request is transmitted from the terminal to the base station 20 as a connection message.

  (7) When the connection message is received, the signal processing unit 34 notifies the movement instruction unit 36 that the connection message has been received. The movement instructing unit 36 instructs the moving unit 23 to stop moving. The moving unit 23 stops moving according to the instruction from the movement instructing unit 36.

  (8) The signal processing unit 34 acquires information included in the connection message and outputs the information to the communication control unit 32. The communication control unit 32 generates a response message to the connection message, transmits the response message to the terminal via the transmission unit 22, and establishes a connection with the terminal. The response message is also transmitted with the same transmission power as the connection response signal. When the connection is established, the communication control unit 32 establishes communication between the terminal, the base station 20, and the core network 11.

  (9) Communication is performed between the terminal and the base station 20. The operation of the base station 20 during communication with the terminal will be described in detail later. When the communication between the terminal and the base station 20 ends, the communication control unit 32 notifies the notification signal control unit 33 of the end of communication. When the notification signal control unit 33 receives the notification from the communication control unit 32, the notification signal control unit 33 resumes transmission of the notification signal to the terminals within the range where the rail 10 is installed.

  As illustrated in FIG. 5, the base station 20 transmits a connection response signal in the cell 60 while moving along the rail 10 until the connection message is received after the connection request signal is received. For this reason, the cell 60 moves as the base station 20 moves. Therefore, even if the terminal is located in the area 3 with poor communication quality, if the terminal enters the cell 60 as the cell 60 moves, the terminal can communicate with the base station 20. In this case, since the base station 20 is located at a distance at which the terminal can receive the connection response signal from the base station 20, the distance from the base station 20 to the terminal is equal to or less than the radius of the cell 60. If the base station 20 is located in the vicinity of the terminal, it can be expected that the communication quality of the terminal is good and the throughput is high, and therefore the communication quality of the terminal communicating with the base station 20 is considered good.

  Furthermore, as described in the procedure (4), after the base station 20 receives the connection request signal, the base station 20 does not establish a connection with terminals other than the terminal that has received the connection request signal. Cancel transmission. Therefore, since the number of terminals connected to the base station 20 is small, the base station 20 can allocate a bandwidth sufficient for terminal communication to the terminals. Therefore, according to the present embodiment, the throughput of the terminal is improved.

  It should be noted that the terminal waits until the terminal receives the connection response signal from the base station 20 after transmitting the connection request signal. Therefore, the terminal can give a guidance to notify the user that “the connection is being prepared” and prompt the user to wait. An arbitrary method can be used to distribute the guidance. Note that guidance distribution is an option, and guidance distribution may not be performed.

  FIG. 6 is a flowchart for explaining an example of the operation of the base station 20 according to the first embodiment. FIG. 6 shows an example of operations performed until the base station 20 establishes a connection with the terminal. FIG. 6 shows an example of the operation. For example, the order of steps S4, S5, and S6 may be arbitrarily changed depending on the implementation of the base station 20.

  When the base station 20 is not communicating with any terminal and is stopped, the notification signal control unit 33 transmits a notification signal to a terminal located in the area where the rail 10 is installed (step S1). . When receiving the connection request signal from the terminal, the signal processing unit 34 acquires the identifier of the terminal from the connection request signal (steps S2 and S3). Also, the notification signal control unit 33 stops transmitting the notification signal (step S4). When the movement instructing unit 36 notified that the connection request signal has been received instructs the moving unit 23 to start moving, the base station 20 starts moving along the rail 10 (step S5). The signal processing unit 34 transmits a connection response signal within the range of the cell 60 toward the terminal that permits the connection (step S6). The signal processing unit 34 confirms whether a connection message has been received from the terminal (step S7). When the connection message is not received, the signal transmission request unit 35 waits while confirming whether or not the connection message is received until the timer 37 set at a certain time expires (No in step S7, step S8). . When the connection message is not received even when the timer 37 expires, the signal transmission request unit 35 requests the transmission unit 22 to transmit the connection response signal to the terminal again at the destination of the base station 20. (Step S6). The base station 20 repeats the operations of steps S6 to S8 while moving along the rail 10 until receiving the connection message. When the base station 20 receives the connection message, the movement instruction unit 36 instructs the movement unit 23 to stop movement. When the moving unit 23 stops moving, the base station 20 stops (step S9). The communication control unit 32 transmits a message that responds to the connection message to the terminal at the stopped position, and establishes a connection with the terminal (step S10).

  Next, the operation of the base station 20 while communicating with the terminal will be described. The base station 20 periodically receives a received power notification message from the terminal. The terminal communication monitoring unit 41 stores the received power included in the received power notification message in the storage unit 24 in association with the time when the received power notification message is received. FIG. 7 shows an example of a table in which received power of the terminal is recorded. When the received power at the terminal falls below the threshold, the base station 20 starts moving and changes the position of the cell 60, thereby improving the received power of the terminal.

  FIG. 8 is a sequence diagram illustrating an example of the operation of the base station 20 during communication with a terminal. A method for the base station 20 to improve the reception power of the terminal will be described with reference to FIG. Further, it is assumed that the received power of the terminal fluctuates as shown in FIG. FIG. 8 shows an example of the operation. For example, the base station 20 moves counterclockwise in the procedure (14), and the base station 20 moves clockwise in the procedure (20). Sometimes.

(11) The terminal transmits a received power notification message to the base station 20.
(12) The terminal communication monitoring unit 41 acquires the received power A of the terminal, and stores it in the storage unit 24 in association with the time when the received power notification message is received in step (11).

  (13) The comparison unit 42 compares the received power A of the terminal with a threshold Th stored in advance. If the received power A of the terminal is greater than or equal to the threshold Th, the procedure returns to step (11). For example, it is assumed that the threshold is −90 dBm. At 12: 00: 00: 00 shown in FIG. 7, the received power is −80 dBm, so the procedure returns to step (11) and the received power of the terminal is continuously observed.

  (14) When the received power A of the terminal is smaller than the threshold value stored in advance, the movement instruction unit 36 instructs the movement unit 23 to start movement. For example, at 12:03:00 shown in FIG. 7, the received power is −100 dBm, which is below the threshold value. The moving unit 23 moves the base station 20 clockwise along the rail 10 in accordance with an instruction from the movement instruction unit 36.

(15) After the base station 20 starts moving along the rail 10 by the moving unit 23, the base station 20 receives a reception power notification message from the terminal.
(16) The terminal communication monitoring unit 41 acquires the reception power notified by the reception notification message received in the procedure (15), and stores it in the storage unit 24. At this time, the terminal communication monitoring unit 41 also stores in the storage unit 24 the time at which the received power notification message was received in step (15).

  (17) The comparison unit 42 compares the received power value acquired last with the received power value acquired before that. For example, when the received power notification message at 12: 00: 00: 00 is the latest, the comparison unit 42 compares the received power value at 12: 00: 00: 00 with the received power value at 12: 00: 00: 00.

  (18) When the received power value acquired last is larger than the received power value acquired before that, the received power of the terminal is increased due to the movement of the base station 20. Therefore, the comparison unit 42 compares the received power value acquired last and the threshold Th. For example, the received power value at 12: 00: 00: 00 is −95 dBm and the received power value at 12: 00: 00: 00 is −100 dBm, so the last received power value is larger than the received power value acquired before that. . Therefore, the comparison unit 42 compares the received power value at 12: 00: 00: 00 with the threshold Th.

  If the received power value acquired last is less than the threshold value Th, the moving unit 23 continues to move, and the processes after the procedure (14) are repeated. For example, since the received power value at 12:04:00 is less than the threshold Th, the moving unit 23 continues to move even when the data at 12:04:00 is processed.

  (19) On the other hand, if the last received power value acquired is equal to or greater than the threshold Th, the movement instructing unit 36 requests the moving unit 23 to stop moving. The moving unit 23 stops moving according to the request. After that, the base station 20 repeats the processing after the procedure (11). For example, when the received power notification message at 12:00 is the latest, the received power value at 12:00 is greater than or equal to the threshold Th, and therefore when the data at 12:00 is processed, the movement instruction The unit 36 requests the moving unit 23 to stop. Then, the moving unit 23 stops moving, and the base station 20 repeats the processes after the procedure (11) at the stopped position.

  (20) In step (17), when the received power value acquired last is smaller than the received power value acquired before that, the communication quality of the terminal has deteriorated due to movement. Therefore, the movement instructing unit 36 notifies the moving unit 23 so that the moving direction is opposite to the moving direction in the procedure (14). Here, the movement instructing unit 36 instructs the moving unit 23 to move counterclockwise. The moving unit 23 changes the moving direction in accordance with an instruction from the movement instruction unit 36. For example, when movement is started based on the received power value of 12:11:00, the received power value of 12:12:00 is compared with the received power value of 12:11:00 in the procedure (17). . The received power value at 12:11:00 is −105 dBm, and the received power value at 12:12:00 is −110 dBm. Accordingly, since the received power of the terminal is reduced as the base station 20 moves in the clockwise direction, the movement instructing unit 36 requests the moving unit 23 to move counterclockwise.

(21) The base station 20 newly receives a received power notification message.
(22) The terminal communication monitoring unit 41 acquires the received power of the terminal, and stores it in the storage unit 24 in association with the time when the received power notification message is received in the procedure (21).

  (23) The received power value acquired in step (22) is compared with the threshold Th. For example, after acquiring the reception power value of 12:12:00, the moving unit 23 changes the moving direction. Therefore, when the reception power value of 12:13:00 is acquired, the comparison unit 42 compares the acquired reception power with the threshold Th. If the received power value acquired at the end is less than the threshold Th, the moving unit 23 continues to move, and the processes after the procedure (20) are repeated. For example, when the reception power value at 12:13:00 is −100 dBm and the threshold value Th is −90 dBm, the reception power value at 12:13:00 is less than the threshold value, and thus the processing from step (20) onward is repeated.

  (24) On the other hand, if the received power value acquired in step (22) is equal to or greater than the threshold Th, the movement instructing unit 36 requests the moving unit 23 to stop moving. The moving unit 23 stops moving according to the request. Thereafter, the base station 20 repeats the processing after the procedure (11).

  Thus, the base station 20 starts moving when the received power at the terminal falls below the threshold, and changes the position of the cell 60 until the communication quality of the terminal improves. Therefore, even if the communication quality of the terminal deteriorates due to the movement of the terminal while communicating with the base station 20, the communication quality of the terminal can be improved by the base station 20 moving the cell 60. it can. In addition, after moving in one direction along the rail 10, the base station 20 determines whether the communication quality of the terminal has improved due to the movement by performing the determination of the procedure (17). When the communication quality of the terminal is degraded due to movement, it can be predicted that the base station 20 is moving away from the terminal due to movement of the base station 20. Therefore, the movement instruction unit 36 changes the movement direction to bring the base station 20 closer to the terminal and improve the communication quality of the terminal. Therefore, by using the base station 20 according to the present embodiment, it is possible to prevent the communication quality of the terminal from being deteriorated during communication.

  Furthermore, the base station 20 according to the present embodiment is also effective when restricting the use of terminals in a partial area of a building. For example, in hospitals and schools, restrict the use of communication by terminals for the purpose of preventing the influence of radio waves on medical devices, preventing obstruction of classes, and preventing inconvenience to people other than users of terminals. It is possible.

  FIG. 9 shows an example of a method for restricting the use of a terminal in a partial area of a building. FIG. 9A is a diagram illustrating an example of the area 5 (5a, 5b) where the use is restricted. In order to restrict communication by terminals in hospital rooms at hospitals and classrooms in schools, corridors and the like may be used as permitted areas. Therefore, the permission area 6 often has an elongated shape as shown in FIG. Therefore, by installing the rail 10 as shown in FIG. 9B, the base station 20 is moved within the permitted area 6 so that the terminal can be communicated at an arbitrary position within the permitted area 6. be able to. In this case, since the cell 60 does not overlap any of the areas 5a and 5b whose usage is restricted, the user of the terminal cannot communicate using the terminal in the areas 5a and 5b whose usage is restricted.

  When the use restriction as shown in FIG. 9A is performed, if the base station 20 is not used, a plurality of base stations 4 (4a to 4k) are installed in the permitted area 6 as shown in FIG. 9C. It will be. When the base station 4 is installed as shown in FIG. 9C, if the cell formed by the base station 4 is circular or elliptical, an area 7 in which the communication quality of the terminal is not good is generated. However, when the base station 20 according to the present embodiment is used, a terminal located anywhere in the permitted area 6 can communicate with the base station 20 as shown in FIG.

  If the base station 20 is not used, a plurality of base stations 4 a to 4 k are installed in the permitted area 6. Therefore, by using the base station 20 according to the present embodiment, the number of installed base stations 20 can be reduced, and the installation cost and operation cost of the base station can be reduced. Further, since the number of installed base stations is small, the base station can be easily managed in the host device. Furthermore, when it is considered that there is no terminal providing the service of the base station 20 such as at night, the power consumption of the system can be suppressed by turning off the base station 20.

  Furthermore, the area which enables communication with the base station 20 can be flexibly set by arbitrarily changing the range in which the rail 10 is installed and the shape of the rail 10. For example, the rail 10 can be installed in a part of the room. Further, since the base station 20 can move along the rail 10, the communication environment of the terminal located near the installation position of the rail 10 is a radio wave caused by a change in the environment around the building or a change in the indoor layout. Less susceptible to changes in state.

<Second Embodiment>
In the second embodiment, a base station 70 that can change the strength of a broadcast signal according to the signal strength from another base station will be described. In order to prevent radio wave interference, it is assumed that the base station other than the base station 70 and the base station 70 communicate with the terminal using different frequency bands. Hereinafter, a case where another base station is a macro cell base station will be described as an example. However, the other base station is not limited to a macro cell base station, and may be a micro cell base station, a pico cell base station, or the like.

  For example, as shown in FIG. 10, it is assumed that radio waves from a macrocell base station 80 installed outdoors reach a room surrounded by a wall 1a. Furthermore, in the area 81 (81a to 81f), the radio wave from the macro cell base station 80 is weak due to the influence of the wall 1 and the obstacle 2, and the communication quality is poor in communication using the radio wave from the macro cell base station. Assume that the base station 70 moves along the rail 10 by the method described in the first embodiment. In addition, the base station 70 can communicate with a terminal located in the cell 60. In such a case, since terminals located outside the areas 81a to 81f may enter the areas 81a to 81f due to movement, it is more stable and better throughput to communicate with the base station 70 than to the macrocell base station 80. May be obtained. Therefore, the base station 70 measures the strength of the broadcast signal from the macro cell base station 80, so that the strength of the broadcast signal of the base station 70 is higher than the strength of the broadcast signal from the macro cell base station 80. Adjust transmit power. In this way, by adjusting the transmission power of the broadcast signal, the base station 70 increases the possibility that the terminal selects the base station 70 as the connection destination rather than the macrocell base station 80.

  FIG. 11 is a diagram illustrating an example of the configuration of the base station 70 according to the second embodiment. The base station 70 includes a receiving unit 72, a transmitting unit 22, a moving unit 23, a storage unit 24, and a control unit 71. The control unit 71 includes a backhaul interface unit 31, a communication control unit 32, a signal processing unit 34, a signal transmission request unit 35, a movement instruction unit 36, a timer 37, a communication monitoring unit 40, and a notification signal control unit 50. The notification signal control unit 50 includes a measurement unit 51, a transmission power adjustment unit 52, a notification signal generation unit 53, and a notification signal search unit 54.

  The receiving unit 72 can receive both an uplink signal transmitted from the terminal and a downlink signal transmitted from the macrocell base station 80 or the like to the terminal. For example, when the frequency band used for transmission / reception of the upstream signal is different from the frequency band used for transmission / reception of the downstream signal, the reception unit 72 may receive both the upstream signal and the downstream signal. It is assumed that it corresponds to the reception of. The reception unit 72 operates in the same manner as the reception unit 21 included in the base station 20 when processing an upstream signal. The receiving unit 72 outputs the upstream signal to the communication control unit 32, the signal processing unit 34, the terminal communication monitoring unit 41, and the like.

  The receiving unit 72 receives and demodulates downlink signals in the same manner as the receiving unit provided in a terminal or the like that communicates with the base station 70. The receiving unit 72 appropriately outputs a downlink signal to the broadcast signal searching unit 54 after performing demodulation or the like.

  The notification signal search unit 54 searches for a notification signal from the signal received from the reception unit 72. For example, the notification signal can be detected by confirming information included in the notification signal such as Mobile Country Codes (MCCs) and Mobile Network Code (MNC) included in the notification signal. When the notification signal is detected, the notification signal search unit 54 notifies the measurement unit 51 that the notification signal has been detected.

  The measuring unit 51 measures the received power of the downlink signal received via the receiving unit 72. When the notification that the notification signal has been detected is received from the notification signal search unit 54, the reception power obtained by the measurement of the measurement unit 51 is the reception power of the notification signal from the macrocell base station 80. The measurement unit 51 notifies the transmission power adjustment unit 52 of the value of the reception power obtained when the notification signal is detected. The transmission power adjustment unit 52 adjusts the transmission power of the notification signal transmitted from the base station 70 so as to have a value larger than the reception power notified from the measurement unit 51. Further, the transmission power adjustment unit 52 notifies the transmission unit 22 of the intensity of the adjusted transmission power. The notification signal generation unit 53 generates a notification signal that the base station 70 transmits to the terminal, and outputs the notification signal to the transmission unit 22. The transmission unit 22 transmits the notification signal input from the notification signal generation unit 53 to the terminal with the transmission power notified from the transmission power adjustment unit 52.

  Operation of the transmission unit 22, the movement unit 23, the storage unit 24, the backhaul interface unit 31, the communication control unit 32, the signal processing unit 34, the signal transmission request unit 35, the movement instruction unit 36, the timer 37, and the communication monitoring unit 40 Is the same as in the first embodiment. That is, when the connection request signal is received, the base station 70 moves along the rail 10 while transmitting the connection response signal within the range of the cell 60. The cell 60 is a narrow range of about several meters centering on the base station 70. The base station 70 moves along the rail 10 until a connection message is received from the terminal. Further, as described with reference to FIGS. 7 and 8, the base station 70 can move according to the received power of the terminal while the communication is established. Further, the backhaul interface unit 31 transmits data to and from the core network 11 via the backhaul relay unit 12 and the connection cables 13 (13a, 13b), as in the first embodiment.

  FIG. 12 is a flowchart showing an example of the operation of the base station 70 according to the second embodiment. FIG. 12 shows an example of operations performed until the base station 70 establishes communication with the terminal. FIG. 12 is an example of the operation. For example, the order of steps S27, S28, and S29 may be arbitrarily changed depending on the implementation of the base station 70.

  When the notification signal transmitted from the macrocell base station 80 is received, the measurement unit 51 measures the reception power of the notification signal (step S21). The transmission power adjustment unit 52 adjusts the transmission power of the notification signal transmitted by the base station 70 to a value larger than the reception power of the notification signal received from the macrocell base station 80 (step S22). The transmission power adjustment unit 52 notifies the transmission unit 22 of the adjusted transmission power. The transmission unit 22 transmits a notification signal to the terminal located in the area where the rail 10 is installed with the notified transmission power (step S23). When receiving the connection request signal from the terminal, the signal processing unit 34 confirms whether the identifier for identifying the base station to which connection is requested by the connection request signal matches the identifier of the base station 70 (step S24, S25). When the identifier for identifying the base station for which connection is requested does not match the identifier for the base station 70, the signal processing unit 34 determines that connection to the base station 70 is not requested. Then, the process after step S21 is repeated. On the other hand, when the identifier for identifying the base station for which connection is requested matches the identifier for the base station 70, the signal processing unit 34 determines that connection to the base station 70 is requested. Therefore, the signal processing unit 34 acquires the ID of the terminal that permits connection from the connection request signal (step S26). The signal processing unit 34 notifies the transmission power adjustment unit 52 and the notification signal generation unit 53 that the connection request signal has been received. Upon receiving the notification from the signal processing unit 34, the notification signal generation unit 53 stops generating the notification signal, and the transmission power adjustment unit 52 also stops adjusting the transmission power of the notification signal. When the notification signal generation unit 53 and the transmission power adjustment unit 52 stop processing, transmission of the notification signal is stopped (step S27). The processing in steps S28 to S33 is the same as that in steps S5 to S10 described with reference to FIG.

  As described above, in the second embodiment, the terminal changes the magnitude of the transmission power of the broadcast signal according to the strength of the broadcast signal transmitted from the macrocell base station 80, so that the terminal sets the base station 70 as the connection destination. The possibility of selecting can be increased. In addition, the base station 70 continues to move along the rail 10 while transmitting a connection response signal within the range of the cell 60, thereby moving until the terminal that has requested connection to the base station 70 enters the cell 60. For this reason, also in 2nd Embodiment, the base station 70 can improve the communication quality of the circumference | surroundings of a terminal similarly to 1st Embodiment. Furthermore, the base station 70 can also improve the throughput of the terminal.

The embodiment is not limited to the above, and can be variously modified. Some examples are described below.
In the above description, the case where the signal processing unit 34 and the signal transmission request unit 35 request the transmission unit 22 to transmit the connection response signal has been described. However, the signal processing unit 34 requests the transmission unit 22 to transmit the connection response signal. It can also be modified so as not to. For example, the connection response signal generated by the signal processing unit 34 and the transmission power of the connection response signal are output to the signal transmission requesting unit 35, and the signal transmission requesting unit 35 transmits the connection response signal according to the input from the signal processing unit 34. A request can be made to the transmitter 22. In this case, in the procedure (5a) of FIG. 5 and step S6 of FIG. 6, the signal transmission request unit 35 requests the transmission unit 22 to transmit the connection response signal transmitted first. Similarly, in step S29, the signal transmission request unit 35 can request the transmission of the connection response signal that is first transmitted to the transmission unit 22.

  In the first embodiment, the case where the transmission of the notification signal is stopped in step S4 of FIG. 6 has been described. However, the notification signal control unit 33 is modified so as not to stop the notification signal even after receiving the connection request signal. There is a case. In this case, the broadcast signal is transmitted within the range of the cell 60 with the same transmission power as the connection response signal. If it deform | transforms in this way, the terminal which entered in the cell 60 when the base station 20 and the terminal which transmitted the connection request signal to the base station 20 are communicating can also establish communication with the base station 20. Therefore, communication quality can be improved for a plurality of users.

  Also in the second embodiment, when the transmission of the notification signal is not stopped in step S27 of FIG. 12, the base station 70 can similarly improve the communication quality of a plurality of users. In this case, the notification signal generation unit 53 does not stop the processing even when receiving a notification that the connection request signal has been received from the signal processing unit 34, and appropriately outputs a notification signal to the transmission unit 22. The transmission unit 22 transmits the notification signal to the terminal in the cell 60 with the same transmission power as the transmission power of the connection response signal.

  In the above description, the case where the guide portion is the rail 10 has been described as an example, but the rail 10 may be appropriately changed to a cable. Moreover, if the base stations 20 and 70 can move along the rail 10 or the cable, the moving method and the installation method of the rail 10 and the like may be arbitrarily changed. For example, the base stations 20 and 70 can move on the rail 10 and the cable. The base stations 20 and 70 may be suspended from the rail 10 or the cable by the moving unit 23.

  Furthermore, the moving part 23 can be modified so as to correspond to a moving method that does not move along the guide part such as the rail 10 or the cable. For example, the moving unit 23 includes a motor and wheels, and moves the base station 20 by moving on the floor on which the base station 20 is placed in accordance with an instruction from the movement instruction unit 36. You can also. As described above, when the guide unit is not used for movement, the base station 20 transmits a broadcast signal with a transmission power that reaches a terminal in a range that is a target for improving communication quality. It is assumed that a range for improving communication quality is set in advance. For example, the notification signal control unit 33 can perform control so that the notification signal is transmitted with transmission power that allows the notification signal to reach one floor of a building.

  In the above description, the case where the base stations 20 and 70 include the timer 37 in the control unit 30 has been described. However, the base stations 20 and 70 may be modified so that the control unit 30 does not include the timer. In this case, the base stations 20 and 70 can be provided with a timer that is realized by other than the CPU that operates as the control unit 30.

  The reception interval when receiving the reception power notification message periodically from the terminal is arbitrary. Therefore, the base stations 20 and 70 may not receive the received power notification message every minute as shown in FIG.

  Further, the base stations 20 and 70 may be set to stop at a certain position on the rail 10 in a state where the base stations 20 and 70 are not communicating with the terminal and have not received a connection request signal from the terminal. In this case, the storage unit 24 stores a stop position, and the moving unit 23 measures a movement amount based on the stopped position. When communication with the terminal is completed, the base station 20 or the base station 70 returns to a predetermined position using the measured movement amount.

The following additional notes are further disclosed for each of the embodiments described above.
(Appendix 1)
A base station device that transmits and receives signals to and from a terminal,
A receiving unit for receiving a signal transmitted from the terminal;
A transmitter for transmitting a signal directed to the terminal;
When a connection request signal transmitted from the terminal is received, a connection response signal responding to the connection request signal is transmitted with a power lower than the transmission power of a notification signal for notifying the terminal of information used to generate the connection request signal A signal transmission requesting unit that requests the transmitting unit to
A base station apparatus comprising: a moving unit that moves the base station apparatus after receiving the connection request signal and before receiving a connection message from a terminal permitted to connect by the connection response signal. .
(Appendix 2)
When the signal transmission request unit does not receive the connection message within a predetermined time after transmitting the connection response signal, the signal transmission request unit requests the transmission unit to transmit the connection response signal,
The transmission unit transmits the connection response signal to a terminal permitted to connect in response to a request from the signal transmission request unit while the base station apparatus is moving. The base station apparatus according to 1.
(Appendix 3)
When a power strength notification for notifying the received power strength of the terminal is received by the receiving unit, a comparing unit that acquires the received power and compares it with a threshold value;
A movement instructing unit that instructs the moving unit to stop moving when the receiving unit receives the connection message, and further instructs the moving unit to start moving when the received power is smaller than a threshold; The base station apparatus according to Supplementary Note 1 or 2, which is characterized.
(Appendix 4)
The moving unit moves the base station apparatus along a guide unit that forms a closed loop path,
After the movement instructing unit instructs the moving unit to start moving, the comparing unit receives the first received power notified by the power intensity notification received at the first time when the movement is started, and Compare the second received power notified by the power strength notification received at the second time after the first time,
The base station apparatus according to supplementary note 3, wherein the movement instructing unit instructs to change a moving direction of the moving unit when the second received power is smaller than the first received power. .
(Appendix 5)
In the radio communication system in which other base stations are installed in addition to the base station according to any one of appendices 1 to 4,
Upon receiving a notification signal transmitted from the other base station via the reception unit, a measurement unit that measures received power of the notification signal transmitted from the other base station;
Any one of appendixes 1 to 4, further comprising: a transmission power adjustment unit that adjusts transmission power of a notification signal transmitted from the transmission unit to be larger than reception power of a notification signal transmitted from the other base station. The base station apparatus as described in.
(Appendix 6)
The base station transmits a notification signal to notify the information used for generating the connection request signal to the terminal,
Upon receiving the connection request signal from the terminal, the base station transmits a connection response signal responding to the connection request signal with power lower than the transmission power of the broadcast signal, and starts moving,
When the base station does not receive a connection message from a terminal permitted to connect with the connection response signal within a predetermined time after transmitting the connection response signal, the base station transmits a connection response signal,
Upon receiving the connection message, the base station stops moving and establishes a connection with a terminal that permits the connection.

DESCRIPTION OF SYMBOLS 1 Wall 2 Obstacle 3 Area 4, 20, 70 Base station 5 Area to restrict use 6 Permitted area 7 Area where terminal communication quality is not good 10 Rail 11 Core network 12 Backhaul relay part 13 Connection cable 21 Receiving part 22 Transmission Unit 23 moving unit 24 storage unit 30, 71 control unit 31 backhaul interface unit 32 communication control unit 33, 50 notification signal control unit 34 signal processing unit 35 signal transmission request unit 36 movement instruction unit 37 timer 40 communication monitoring unit 41 terminal communication Monitoring unit 42 Comparison unit 51 Measurement unit 52 Transmission power adjustment unit 53 Broadcast signal generation unit 54 Broadcast signal search unit 60 Cell 72 Reception unit 80 Macrocell base station

Claims (5)

A base station device that transmits and receives signals to and from a terminal,
A receiving unit for receiving a signal transmitted from the terminal;
A transmitter for transmitting a signal directed to the terminal;
When a connection request signal transmitted from the terminal is received, a connection response signal responding to the connection request signal is transmitted with a power lower than the transmission power of a notification signal for notifying the terminal of information used to generate the connection request signal A signal transmission requesting unit that requests the transmitting unit to
A base station apparatus comprising: a moving unit that moves the base station apparatus after receiving the connection request signal and before receiving a connection message from a terminal permitted to connect by the connection response signal. . When the signal transmission request unit does not receive the connection message within a predetermined time after transmitting the connection response signal, the signal transmission request unit requests the transmission unit to transmit the connection response signal,
The transmission unit transmits the connection response signal to a terminal permitted to connect in response to a request from the signal transmission request unit while the base station apparatus is moving. Item 8. The base station apparatus according to Item 1. When a power strength notification for notifying the received power strength of the terminal is received by the receiving unit, a comparing unit that acquires the received power and compares it with a threshold value;
A movement instructing unit that instructs the moving unit to stop moving when the receiving unit receives the connection message, and further instructs the moving unit to start moving when the received power is smaller than a threshold; The base station apparatus according to claim 1 or 2, characterized in that In addition to the base station according to any one of claims 1 to 3, in a wireless communication system in which another base station is installed,
Upon receiving a notification signal transmitted from the other base station via the reception unit, a measurement unit that measures received power of the notification signal transmitted from the other base station;
The transmission power adjustment part which adjusts the transmission power of the alerting signal transmitted from the said transmission part larger than the reception power of the alerting | reporting signal transmitted from the said other base station is provided. The base station apparatus as described in. The base station transmits a notification signal to notify the information used for generating the connection request signal to the terminal,
Upon receiving the connection request signal from the terminal, the base station transmits a connection response signal responding to the connection request signal with power lower than the transmission power of the broadcast signal, and starts moving,
When the base station does not receive a connection message from a terminal permitted to connect with the connection response signal within a predetermined time after transmitting the connection response signal, the base station transmits a connection response signal,
Upon receiving the connection message, the base station stops moving and establishes a connection with a terminal that permits the connection.