JP6351846B2 - Antenna control device - Google Patents

Description

  The present application relates to an antenna control device that controls a plurality of distributed antennas.

  One of the antenna configurations of a wireless communication system that realizes wireless communication with a mobile station moving at high speed in a high-speed land mobile environment represented by an expressway and a railroad is a linear distributed antenna configuration. The linear distributed antenna configuration is characterized by having an antenna facility that installs a plurality of antennas distributed along the path of the mobile station. Also, in a wireless communication system having a linear distributed antenna configuration, a plurality of antennas are extended along the moving direction of a mobile station moving at high speed, and the same signal is sent to the mobile station via each antenna. Thus, there is a communication area that transmits synchronously from a base station, that is, a so-called linear cell.

  The linear cell can limit the radiation direction or directivity (sensitivity direction) of the antenna to the moving range of the mobile station. For this reason, the linear cell can extend the communication range handled by one antenna as compared to the case of using an omnidirectional antenna. As a result, the linear cell can reduce the number of antennas required to construct the antenna equipment.

Japanese Patent No. 4371339 JP 2013-183257 A

  Since linear cells transmit and receive the same signal synchronously at the same frequency via multiple antennas, there is a risk of overreach where radio waves reach nearby communication areas using the same frequency, causing radio interference in the communication area. is there. Radio wave interference due to overreach causes degradation of communication quality.

  The present invention has been made in view of the above, and an object of the present invention is to provide an antenna control apparatus capable of reducing radio wave interference to neighboring communication areas using the same frequency.

  In order to solve the above-described problems and achieve the object, the present invention provides a plurality of antennas that transmit and receive signals generated by a base station to and from a mobile station that moves on a predetermined route. A radio communication system comprising a plurality of linear cells formed by being installed along an antenna control device for controlling transmission / reception of signals performed via the antenna, wherein the mobile station is located in the linear cell. A first signal for confirming whether or not the second signal is transmitted periodically through the plurality of antennas, and based on whether or not a second signal that is a response signal to the first signal is received, The mobile station existing in the linear cell is detected, and data transmission with the mobile station is executed using the antenna selected based on the reception level of the second signal.

  According to the present invention, it is possible to reduce radio wave interference to neighboring communication areas using the same frequency.

The figure which shows the structural example of the radio | wireless communications system which concerns on Embodiment 1. FIG. The figure which shows the example of the signal produced | generated by a base station FIG. 3 is a block diagram illustrating an example of a functional configuration of the antenna control device according to the first embodiment. The figure which shows the outline | summary of the process of the antenna control apparatus which concerns on Embodiment 1. FIG. The flowchart which shows the flow of a process of the antenna control apparatus which concerns on Embodiment 1. FIG. Diagram for explaining radio wave interference between linear cells The figure which shows the structural example of the radio | wireless communications system which concerns on Embodiment 2. FIG. The flowchart which shows the flow of a process of the antenna control apparatus which concerns on Embodiment 3. FIG. The figure which shows the outline | summary of a process of the antenna control apparatus which concerns on Embodiment 3. FIG. The figure which shows the modification of the linear cell which comprises a radio | wireless communications system. The figure which shows the hardware structural example of a computer

  Hereinafter, an antenna control device according to an embodiment of the present invention will be described in detail with reference to the drawings. The invention is not limited to the embodiments.

  The radio communication system according to each embodiment described below assumes a system having a multi-linear cell configuration in which a plurality of linear cells are linearly installed. The wireless communication system according to each embodiment is a wireless communication between a communication device mounted on a moving body that moves along a predetermined route, such as a train traveling on a track and a vehicle traveling on a highway. In addition, it is assumed that wireless communication is performed with an independent communication device possessed by a person who gets on a train and a vehicle. In the following description, a communication device mounted on a moving body such as a train and a vehicle and a communication device possessed by a person who gets on the train and the vehicle are collectively referred to as a mobile station.

  The radio communication system according to each embodiment can apply frequency repetition when assigning a frequency for signal transmission to each linear cell. Frequency repetition is one frequency selected from several frequencies for each of the linear cells in accordance with a repetition pattern composed of several frequencies so that the frequency used for signal transmission differs between adjacent linear cells. Assign. The radio communication system according to each embodiment can employ any number of repetitions such as two-frequency repetition and three-frequency repetition. Each linear cell transmits a signal generated by the base station using a frequency assigned to the own cell.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a radio communication system 10 according to the first embodiment. As shown in FIG. 1, a radio communication system 10 according to Embodiment 1 includes a base station 1, a plurality of distributed antennas 3-1a,..., 3-Na, an antenna control device 4, and a range 5- 1a,..., A linear cell 5 formed in the range 5-Na. In the example shown in FIG. 1, an example is shown in which a train that is the mobile station 2 moves on a track that is a predetermined route 8.

  The base station 1 generates a signal to be transmitted toward the mobile station 2. FIG. 2 is a diagram illustrating an example of a signal generated by the base station. In the example shown in FIG. 2, the signal generated by the base station 1 is configured to include a presence line confirmation channel C1 and a data transmission channel C2. The presence line confirmation channel C1 is a channel corresponding to transmission of a beacon or the like for confirming whether the mobile station 2 exists in the linear cell. The data transmission channel C2 is a channel corresponding to transmission of various data signals exchanged between the base station 1 and the mobile station 2.

  A plurality of distributed antennas 3-1a,..., 3-Na (hereinafter referred to as “distributed antennas”) are generated by the base station 1 with the mobile station 2 moving on a predetermined path 8. Send a signal. The distributed antenna has directivity. The distributed antenna is installed in a state where the sensitivity direction is aligned with the moving direction of the mobile station 2 moving at high speed. Each distributed antenna is individually responsible for the communication range. For example, as shown in FIG. 1, the distributed antenna 3-1a is responsible for the range 5-1a, and the distributed antenna 3-Na is responsible for the range 5-Na. The linear cell shown in FIG. 1 forms one communication area with the total range of the ranges 5-1a,. The distributed antennas 3-1a,..., 3-Na are examples of antennas.

  The antenna control device 4 controls signal transmission / reception performed via the distributed antenna. FIG. 3 is a block diagram illustrating a functional configuration example of the antenna control apparatus according to the first embodiment. The antenna control device 4 includes an antenna control unit 41 and a power adjustment unit 42. The antenna control unit 41 is an example of an antenna control unit. The power adjustment unit 42 is an example of a power adjustment unit.

  The antenna control unit 41 periodically transmits an on-line confirmation signal for confirming whether the mobile station 2 exists in the linear cell via each of the distributed antennas 3-1a,. And the antenna control part 41 detects the mobile station 2 which exists in a linear cell based on the presence or absence of reception of the standing line response signal which is a response signal with respect to a standing line confirmation signal. Specifically, the antenna control unit 41 confirms reception of the standing line response signal via at least one of the distributed antennas 3-1a,..., 3-Na, and enters the mobile station 2 in the linear cell. Is determined to be detected. The standing line confirmation signal is an example of a first signal, and the standing line response signal is an example of a second signal.

  Further, when the mobile station 2 is detected, the antenna control unit 41 uses a distributed antenna whose reception level, which is the strength of the standing line response signal, is greater than or equal to a threshold value from among a plurality of distributed antennas. Data transmission between them. The antenna control unit 41 uses the average of the instantaneous values of signals received by the presence line confirmation channel C1 within a certain time after each of the antennas transmits the standing line response signal as the reception level. An RSSI (Received Signal Strength Indicator) can be used as an indicator of the reception level.

  The power adjustment unit 42 adjusts the transmission power when transmitting a signal from the distributed antenna according to the reception level of the standing line response signal. For example, the power adjustment unit 42 makes the transmission power of the distributed antenna whose reception level of the standing line response signal is equal to or greater than the threshold value smaller than the transmission power at the normal time. Alternatively, the power adjustment unit 42 may adjust the transmission power of the distributed antenna so that the transmission power decreases as the reception level of the standing line response signal increases.

  FIG. 4 is a diagram showing an outline of processing of the antenna control apparatus according to Embodiment 1. As step S11, the antenna control device 4 sends a standing line confirmation signal 6a for confirming whether the mobile station 2 exists in the linear cell at a predetermined timing to each of the distributed antennas 3-1a,. Periodically.

  Subsequently, in step S12, when the antenna control device 4 detects the mobile station 2, the antenna control device 4 replaces the distributed antennas 3-1a,. .., detected from 3-Na. When the antenna control device 4 detects the distributed antenna 3-1a and the distributed antenna 3-2a as distributed antennas whose reception level of the standing line response signal 7 is equal to or greater than the threshold, the antenna control device 4 uses the distributed antenna 3-1a and the distributed antenna 3-2a. To select the antenna that transmits the data signal 6b. Subsequently, the antenna control device 4 adjusts the transmission power of the signals of the distributed antenna 3-1a and the distributed antenna 3-2a according to the reception level of the standing line response signal 7. And the antenna control apparatus 4 performs data transmission using the distributed antenna 3-1a and the distributed antenna 3-2a.

  FIG. 5 is a flowchart showing a process flow of the antenna control apparatus according to the first embodiment. As shown in FIG. 5, the antenna control device 4 transmits a standing line confirmation signal 6a via each of the distributed antennas at a predetermined timing (step S101).

  Subsequently, the antenna control device 4 determines whether the mobile station 2 has been detected based on the presence / absence of reception of the standing line response signal 7 transmitted from the mobile station 2 as a response to the standing line confirmation signal 6a (step S102). For example, the antenna control device 4 determines that the mobile station 2 exists in the linear cell at the time when the reception of the standing line response signal 7 transmitted from the mobile station 2 is confirmed.

  When the mobile station 2 is detected as a result of the determination (step S102, Yes), the antenna control device 4 detects a distributed antenna whose reception level of the standing line response signal 7 received by the distributed antenna is equal to or greater than a threshold ( Step S103).

  Subsequently, the antenna control device 4 adjusts the transmission power of the distributed antenna in accordance with the reception level of the standing line response signal 7 (step S104). Subsequently, the antenna control device 4 executes data transmission using the distributed antenna detected in step S103 (step S105), and returns to the determination in step S101.

  If the mobile station 2 is not detected in step S102 as a result of the determination (step S102, No), the antenna control device 4 returns to the determination in step S101.

  As described above, the antenna control device 4 transmits the standing line confirmation signal 6a from each of the distributed antennas, and moves using the distributed antenna in which the reception level of the standing line response signal 7 transmitted from the mobile station 2 exceeds the threshold value. Data transmission with the station 2 is executed. That is, the antenna control device 4 can select a distributed antenna that contributes to data transmission with the mobile station 2 from the distributed antennas. For this reason, according to Embodiment 1, the number of antennas used for data transmission among a plurality of antennas constituting a linear cell can be reduced, and radio wave interference to neighboring communication areas using the same frequency can be reduced. According to the first embodiment, since the wireless communication system includes the linear cell, the number of antennas is reduced to reduce the system weight, and the number of antennas that perform data transmission is reduced. The amount can be reduced.

  Further, since the antenna control device 4 adjusts the transmission power of the distributed antenna according to the reception level of the standing line response signal 7, it is possible to maintain the communication quality while reducing the radio wave interference. FIG. 6 is a diagram for explaining radio wave interference between linear cells. A radio communication system having a multi-linear cell configuration is a so-called overreach in which a signal radiated from one cell leaks to the other cell due to the presence of a plurality of linear cells that transmit signals using the same frequency. Causes an interfered cell. On the other hand, in the example shown in FIG. 6, the antenna control apparatus 4 adjusts the transmission power of the distributed antenna so that the higher the reception level of the standing line response signal 7 is, the lower the transmission power is. The transmission power of the distributed antenna 3-1a closest to can be reduced. For this reason, the antenna control device 4 can reduce the influence on the interfered cell.

  In the first embodiment, the example in which data transmission with the mobile station 2 is performed using the distributed antenna in which the reception level of the standing line response signal 7 transmitted from the mobile station 2 exceeds the threshold has been described. This is not a limitation. For example, data transmission may be performed using a distributed antenna whose reception level of the standing line response signal 7 exceeds a threshold and at least one of a plurality of other distributed antennas installed in the vicinity of the distributed antenna. . Specifically, for example, when the reception level of the distributed antenna 3-2a exceeds a threshold value, the antenna control device 4 disperses the distributed antenna 3-2a and the distributed antenna installed in the vicinity of the distributed antenna 3-2a. Data transmission with the mobile station 2 can be executed using at least one of the 3-1a and the distributed antenna 3-3a. Thereby, for example, even when there is only one distributed antenna whose reception level of the on-line response signal 7 exceeds the threshold, data transmission is performed using the distributed antenna and the distributed antenna installed in the vicinity of the distributed antenna. As a result, the communication quality can be improved. The distributed antenna installed near the distributed antenna whose reception level of the standing line response signal 7 exceeds the threshold may be a distributed antenna installed adjacent to the distributed antenna whose reception level exceeds the threshold. Alternatively, the distributed antenna installed in the vicinity of the distributed antenna whose reception level of the standing line response signal 7 exceeds the threshold value may be a distributed antenna installed within a certain distance from the distributed antenna.

Embodiment 2. FIG.
The wireless communication system may include a plurality of distributed antennas grouped for each sensitivity direction in a linear cell and control signal transmission and reception for each group. FIG. 7 is a diagram illustrating a configuration example of a wireless communication system according to the second embodiment. As shown in FIG. 7, the radio communication system according to Embodiment 2 includes distributed antennas 3-1a,..., 3-Na, distributed antennas 3-1b,. A device 4a and an antenna control device 4b are provided. The distributed antennas 3-1b,..., 3-Nb having directivity in a specific direction are installed so that the sensitivity direction is opposite to that of the distributed antennas 3-1, a,. . The antenna control device 4a controls signal transmission / reception performed via each of the distributed antennas 3-1a,..., 3-Na. The antenna control device 4b controls signal transmission / reception performed via each of the distributed antennas 3-1b,..., 3-Nb. The antenna control device 4a and the antenna control device 4b execute processing similar to the processing described in the first embodiment. That is, the antenna control device 4a and the antenna control device 4b each independently detect the mobile station 2 and select an antenna to be used for data transmission.

  In the second embodiment, a plurality of directional distributed antennas are grouped for each sensitivity direction, and the antenna control device 4a and the antenna control device 4b execute the same processing as in the first embodiment for the groups that they are responsible for. . For this reason, according to the second embodiment, for each group of a plurality of distributed antennas grouped in the sensitivity direction, the same effect as in the first embodiment, that is, the number of antennas used for data transmission is reduced, and the same frequency The effect of reducing the radio wave interference to the nearby communication area using can be exhibited. Further, according to the second embodiment, the communication probability can be increased by installing the distributed antennas having different sensitivity directions.

Embodiment 3 FIG.
In the following third embodiment, processing of an antenna control device different from that of the first embodiment will be described. The antenna control device 4 according to the third embodiment is different from the first embodiment in the points described below.

  Until the mobile station 2 is detected, the antenna control unit 41 sends an on-line confirmation signal 6a for confirming whether the mobile station 2 exists in the linear cell, and transmits each of the distributed antennas installed at both ends of the linear cell. And periodically transmitting to start detection of the mobile station 2.

  When the mobile station 2 is detected, the antenna control unit 41 detects the presence check signal 6a and the presence check signal 6a each time the first antenna whose reception level of the presence response signal 7 exceeds the threshold is detected as follows. Control the antenna that performs data transmission. First, the antenna control unit 41 uses the first antenna and the second antenna installed adjacent to the first antenna on the moving direction side of the mobile station 2 to transmit the presence line confirmation signal 6a and the data signal. The transmission of 6b is executed. Subsequently, when there is a third antenna installed adjacent to the first antenna on the side opposite to the moving direction of the mobile station 2, the antenna control unit 41 is the end antenna. On the condition that there is not, the transmission of the on-line confirmation signal 6a and the transmission of the data signal 6b which are being executed through the third antenna are stopped. On the other hand, when there is a third antenna installed adjacent to the first antenna on the side opposite to the moving direction of the mobile station 2, the antenna control unit 41 is an end antenna. On the condition, only the transmission of the data signal 6b is stopped among the transmission of the on-line confirmation signal 6a and the transmission of the data signal 6b which are being executed through the third antenna. The moving direction described above corresponds to a direction from the antenna side where the standing line response signal 7 is received toward the antenna side where the standing line response signal 7 is not received.

  Hereinafter, the flow of processing of the antenna control device 4 according to Embodiment 3 will be described with reference to FIGS. 8 and 9. FIG. 8 is a flowchart showing a process flow of the antenna control apparatus according to the third embodiment. FIG. 9 is a diagram illustrating an outline of processing of the antenna control apparatus according to the third embodiment. In the following description, what is simply expressed as “cell” corresponds to a linear cell. In the following description, what is simply denoted as “antenna” corresponds to the above-described distributed antenna.

  For example, as shown in step S21 of FIG. 9, the antenna control device 4 transmits the presence line confirmation signal 6a using the antennas 3-1a and the antenna 3-Na installed at both ends of the cell. Then, detection of the mobile station 2 is started. The antenna control device 4 performs the same processing in either case when the mobile station 2 is detected on the side where the antenna 3-1a is installed or when the mobile station is detected on the side where the antenna 3-Na is installed. Run. Therefore, hereinafter, as an example of processing, a case where the mobile station 2 is detected on the side where the antenna 3-1a is installed will be described.

  The antenna control device 4 determines whether the reception level of the standing line response signal 7 received by the antenna 3-1a is equal to or higher than the threshold (step S201).

  As a result of the determination, the antenna control device 4 repeats the determination when the reception level of the standing line response signal 7 received by the antenna 3-1a is not equal to or higher than the threshold (No in step S201).

  On the other hand, as a result of the determination, when the reception level of the on-line response signal 7 received by the antenna 3-1a is equal to or higher than the threshold value (Yes in Step S201), for example, as shown in Step S22 of FIG. The transmission of the data signal 6b is started using the antenna 3-1a and the antenna 3-2a adjacent to the antenna 3-1a (step S202). Furthermore, in conjunction with the start of transmission of the data signal 6b, the antenna control device 4 starts transmission of the presence line confirmation signal 6a from the antenna 3-2a (step S203).

  Subsequently, the antenna control device 4 determines whether or not the reception level of the standing line response signal 7 received by the antenna 3-2a is equal to or higher than the threshold (step S204).

  As a result of the determination, when the reception level of the standing line response signal 7 received by the antenna 3-2a is not equal to or higher than the threshold value (No in step S204), the antenna control device 4 repeats the determination.

  On the other hand, when the reception level of the standing line response signal 7 received by the antenna 3-2a is equal to or higher than the threshold value as a result of the determination (Yes in Step S204), for example, as shown in Step S23 of FIG. The antenna 3-1a switches to the transmission of the on-line confirmation signal 6a only, and starts the transmission of the data signal 6b using the antenna 3-3a adjacent to the antenna 3-2a (step S205). That is, the antenna control device 4 stops only the transmission of the data signal 6b among the transmissions of the standing line confirmation signal 6a and the data signal 6b that are being executed via the antenna 3-1a. Further, in conjunction with the start of transmission of the data signal 6b, the antenna control device 4 starts transmission of the presence line confirmation signal 6a from the antenna 3-3a (step S206).

  Subsequently, the antenna control device 4 determines whether or not the reception level of the standing line response signal 7 received by the antenna 3-3a is equal to or higher than the threshold value (step S207).

  As a result of the determination, the antenna control device 4 repeats the determination when the reception level of the standing line response signal 7 received by the antenna 3-3a is not equal to or higher than the threshold (No in step S207).

  On the other hand, as a result of the determination, when the reception level of the on-line response signal 7 received by the antenna 3-3a is equal to or higher than the threshold (Yes in Step S207), for example, as shown in Step S24 of FIG. Then, the transmission of all signals (the on-line confirmation signal 6a and the data signal 6b) at the antenna 3-2a is stopped, and the transmission of the data signal 6b is started using the antenna 3-4a adjacent to the antenna 3-3a ( Step S208). Furthermore, in conjunction with the start of transmission of the data signal 6b, the antenna control device 4 starts transmission of the presence line confirmation signal 6a from the antenna 3-4a (step S209).

  Thereafter, until the transmission of the data signal 6b from the antenna 3-Na is started, the antenna control device 4 performs the same processing procedure as the processing procedure from step S208 to step S210 for each of the other antennas other than the antennas described above. Executed.

  After starting transmission of the data signal 6b from the antenna 3-Na, the antenna control device 4 determines whether or not the reception level of the on-line response signal 7 received by the antenna 3-Na is equal to or higher than a threshold (step S210).

  As a result of the determination, when the reception level of the standing line response signal 7 received by the antenna 3-Na is not equal to or higher than the threshold value (No in step S210), the antenna control device 4 repeats the determination.

  On the other hand, as a result of the determination, when the reception level of the standing line response signal 7 received by the antenna 3-Na is equal to or higher than the threshold value (step S210, Yes), the antenna control device 4 performs the antenna control as shown in step S25 of FIG. Transmission of all signals from all antennas other than 3-1a and antenna 3-Na is stopped (step S211). That is, the antenna control device 4 stops transmission of the on-line confirmation signal 6a and the data signal 6b that are being executed via all antennas other than the antenna 3-1a and the antenna 3-Na.

  Subsequently, the antenna control device 4 determines whether or not the reception level of the standing line response signal 7 received by the antenna 3-Na is less than the threshold value (step S212).

  As a result of the determination, when the reception level of the standing line response signal 7 received by the antenna 3-Na is not less than the threshold (No in step S212), the antenna control device 4 repeats the determination.

  On the other hand, when the reception level of the standing line response signal 7 received by the antenna 3-Na is less than the threshold value as a result of the determination (Yes in step S212), the antenna control device 4 transmits the data signal 6b from the antenna 3-Na. Is stopped (step S213), and the process returns to the determination in step S201.

  Until the mobile station 2 is detected, the antenna control apparatus 4 according to Embodiment 3 limits the distributed antennas that transmit the standing line confirmation signal 6a to only distributed antennas installed at both ends of the linear cell. After the mobile station 2 is detected, the antenna control apparatus 4 according to the third embodiment adds the distributed antenna that transmits the standing line confirmation signal 6a to the distributed antennas installed at both ends of the linear cell, and It is limited to a distributed antenna whose reception level is equal to or higher than a threshold and a distributed antenna installed on the moving direction side of the mobile station 2 among adjacent antennas of the distributed antenna. Further, the antenna control apparatus 4 according to Embodiment 3 moves the distributed antenna that transmits the data signal 6b among the distributed antennas whose reception level of the standing line response signal 7 is equal to or higher than the threshold and the distributed antennas adjacent to the distributed antenna. It is limited to the distributed antenna installed on the moving direction side of the station 2. For this reason, according to the third embodiment, since the distributed antennas for transmitting signals are further limited according to the positional relationship between the mobile station 2 and the distributed antennas, radio wave interference to neighboring communication areas using the same frequency is prevented. Further reduction can be achieved. Further, according to the third embodiment, since data transmission to and from the mobile station 2 is always executed by a plurality of distributed antennas, it is possible to prevent deterioration in communication quality.

  For example, the antenna control device 4 may execute the above-described processing (see FIGS. 8 and 9) for each group for a plurality of distributed antennas grouped for each sensitivity direction illustrated in FIG. 7.

  As described above, the antenna control device 4 according to Embodiment 3 uses the distributed antennas installed at both ends of the linear cell as the distributed antenna that transmits the standing line confirmation signal 6a until the mobile station 2 is detected. explained. However, the present invention is not limited to this example. For example, out of the distributed antennas installed at both ends of the linear cell until the mobile station 2 is detected, the presence line confirmation is performed only from the antenna on the side where the mobile station 2 enters the linear cell. The signal 6a may be transmitted. That is, when the moving direction of the mobile station 2 is limited in advance, radio interference can be further reduced by further limiting the distributed antennas that transmit the standing line confirmation signal 6a.

  FIG. 10 is a diagram illustrating a modification of the linear cell constituting the wireless communication system. 10 includes a base station 1, a plurality of distributed antennas 3-1a,..., 3-Na protruding from the base station 1 along one path, The antenna control device 4 includes the distributed antennas 3-1c,..., 3-Mc protruding from the base station 1 along the other path that exchanges with the path. As shown in FIG. 10, even when linear cells are formed along a branching path, the same processing as in each of the above embodiments can be applied.

  FIG. 11 is a diagram illustrating a hardware configuration example of the antenna control devices 4, 4a, and 4b according to the first to third embodiments. The processing by the antenna control device 4 described in the first to third embodiments can be realized by the computer 100 shown in FIG.

  The computer 100 includes, for example, a processor 101, a RAM (Random Access Memory) 102, a ROM (Read Only Memory) 103, an input interface (I / F) 104, an output interface (I / F) 105, and a communication interface (I / F). 106, bus 107, and the like. Each piece of hardware is connected via a bus 107.

  The RAM 102 is a readable / writable memory device. For example, a semiconductor memory such as an SRAM (Static RAM) or a DRAM (Dynamic RAM), or a flash memory even if not a RAM is used. The ROM 103 stores a program that realizes a function provided by the antenna control unit 41 included in the antenna control device 4 and a function corresponding to the power adjustment unit 42 included in the antenna control device 4. The ROM 103 includes a PROM (Programmable ROM) and the like.

  The input interface 104 is connected to the antennas 300a,. The input interface 104 is a circuit that transmits an input signal input from the antennas 300a,. The output interface 105 is connected to the antennas 300a,. The output interface 105 is a circuit that causes the antennas 300a,... The communication interface 106 is a circuit that controls communication performed with the base station 200 via the network 70. The communication interface 106 is, for example, a network interface card (NIC: Network K Interface Card). The input interface 104 and the output interface 105 may be an integrated unit. The base station 200 corresponds to, for example, the base station 1 illustrated in FIGS. 1, 4, 6, 7, 9, and 10. The antennas 300a,..., And the antenna 300n correspond to, for example, the antennas 3-1a,..., And the antenna 3-Na shown in FIGS. 1, 4, 6, 7, 9, and 10.

  The processor 101 reads out a program stored in the ROM 103, expands it in the RAM 102, and executes instructions included in the program expanded in the RAM 102. When the antenna control device 4 operates according to the execution result of the command included in the program, the processing corresponding to the function provided by the antenna control unit 41 and the processing corresponding to the function provided by the power adjustment unit 42 are realized. Is done. When the processor 101 executes instructions, the RAM 102 is used as a work area for the processor 101.

  As shown in FIG. 11, the processor 101 is limited to an example that realizes processing corresponding to the antenna control unit 41 and the power adjustment unit 42 included in the antenna control device 4 by reading and executing a program stored in the ROM 103. Not. A plurality of processing circuits for realizing the function provided by the antenna control unit 41 may cooperate to implement processing corresponding to the function provided by the antenna control unit 41. Similarly, a plurality of processing circuits for realizing the function provided by the power adjustment unit 42 may cooperate to implement processing corresponding to the function provided by the power adjustment unit 42.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  DESCRIPTION OF SYMBOLS 1 Base station, 2 Mobile station, 3-1a, ..., 3-Na Distributed antenna, 4 Antenna control apparatus, 5 Linear cell, 8 path | route, 10 Wireless communication system, 41 Antenna control part, 42 Power adjustment part.

Claims (6)

A radio comprising a plurality of linear cells formed by installing, along the path, a plurality of antennas that transmit signals generated by the base station to / from a mobile station moving along a predetermined path In a communication system, an antenna control apparatus for controlling transmission / reception of a signal performed via the antenna,
A first signal for confirming whether the mobile station exists in the linear cell is periodically transmitted via the plurality of antennas, and a second signal that is a response signal to the first signal is received. Detecting the mobile station present in the linear cell based on the presence or absence of
An antenna control unit that performs data transmission with the mobile station using the antenna selected based on the reception level of the second signal ;
The antenna controller is
The first signal is periodically transmitted from at least one of end antennas installed at both ends of the linear cell among the plurality of antennas,
When the mobile station is detected, each time the first antenna whose reception level exceeds a threshold is detected, the first antenna and the first antenna on the moving direction side of the mobile station Performing transmission of the first signal and the data transmission using a second antenna installed adjacently,
When there is a third antenna installed adjacent to the first antenna on the opposite side to the moving direction of the mobile station, the third antenna is the end antenna, provided that the third antenna is the end antenna. Of the transmission of the first signal and the data transmission being performed via the third antenna, only the data transmission is stopped,
On condition that the third antenna is not the end antenna, antenna control characterized that you stop transmission and the data transmission of said third of said first signals running through the antenna apparatus. The antenna controller is
When the mobile station is detected, data transmission to the mobile station is performed using an antenna having a reception level of the second signal equal to or higher than a threshold value among the plurality of antennas. The antenna control device according to claim 1.   The antenna control apparatus according to claim 1, further comprising: a power adjustment unit that adjusts transmission power of the antenna according to a reception level of the second signal. The antenna controller is
The data transmission is performed by using at least one of an antenna whose reception level of the second signal exceeds a threshold and a plurality of other antennas installed in the vicinity of the antenna. The antenna control device according to any one of claims 1 to 3. The wireless communication system includes a plurality of antennas grouped for each sensitivity direction in the linear cell,
The antenna controller is
For each group, perform detection of the mobile station,
The data transmission to the mobile station is executed for each group using an antenna having a reception level of the second signal equal to or higher than a threshold value among the plurality of antennas. 5. The antenna control device according to any one of 4. The wireless communication system includes a plurality of antennas grouped for each sensitivity direction in the linear cell,
The antenna controller is
For each group, perform detection of the mobile station,
In each group, the transmission and the selection of an antenna used for the data transmission of the first signal, and an antenna control device according to claim 1, characterized in that to perform the cancellation of the selection.

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