JP2011114545A - Repeater, gain control method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a service with the maximum gain that does not cause oscillation while suppressing a deterioration in the service for a user without making a circuit configuration complicated. <P>SOLUTION: The repeater has first and second antennas, amplifies a signal received by the first antenna, transmits the amplified signal from the second antenna, also amplifies a signal received by the second antenna, and transmits the amplified signal from the first antenna. When the power level of the signal received by the first antenna is not higher than a predetermined first threshold, the repeater determines whether an oscillation occurs on the basis of the power level of the signal received by the second antenna, and determines a new gain on amplifying the signal received by the second antenna in accordance with a determination result. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a repeater, a gain control method, and a program for amplifying and transmitting a received signal.

  In mobile communication systems, repeaters are used to improve radio wave reception conditions in areas where radio waves from base stations are difficult to reach.

  The repeater amplifies and relays a signal transmitted / received by radio waves between a mobile station (user) existing in an area where radio waves from the base station are difficult to reach and the base station. Thereby, even when the mobile station exists in an area where radio waves from the base station are difficult to reach, it is possible to receive a service provided by the mobile communication carrier. Hereinafter, the range in which the amplified signal from the repeater reaches is referred to as a service providing range.

  The repeater normally has two types of antennas: a base station side antenna that transmits and receives signals to and from the base station, and a mobile station side antenna that transmits and receives signals to and from the mobile station. Hereinafter, a signal in a direction transmitted from the base station to the repeater and received by the base station antenna is referred to as a downlink (downlink) signal. A signal in a direction transmitted from the mobile station to the repeater and received by the mobile station side antenna is referred to as an uplink (uplink) signal.

  The base station side antenna receives the downlink signal transmitted from the base station and transmits the amplified uplink signal to the base station. The mobile station side antenna receives an uplink signal transmitted from the mobile station, and transmits an amplified downlink signal to the mobile station.

  Here, the base station side antenna and the mobile station side antenna described above handle radio waves of the same frequency. Therefore, if the gain at the time of signal amplification is increased in order to make the service provision range as wide as possible, oscillation will occur due to the amplified signal transmitted from one antenna wrapping around the other antenna. May end up.

  Specifically, the oscillation is caused, for example, when an amplified downlink signal transmitted from the mobile station side antenna interferes with a downlink signal received by the base station side antenna. If oscillation occurs, the mobile communication carrier cannot provide a service to the user.

  As a method for avoiding the occurrence of oscillation, there is a method in which the base station side antenna and the mobile station side antenna are installed sufficiently apart. However, with this method, the installation location of the repeater is limited or the installation work of the repeater becomes complicated.

  Therefore, for example, Patent Document 1 discloses a technique that can avoid the occurrence of oscillation while reducing the burden on installation as described above.

  In the technique disclosed in Patent Document 1, the maximum gain at which oscillation does not occur between antennas installed as far apart as possible in accordance with the installation environment is automatically set.

  As another method for avoiding the occurrence of oscillation, for example, Patent Document 2 discloses a technique in which an interference canceller that detects interference between antennas and cancels the detected interference is provided in a repeater (relay amplifier). It is disclosed.

JP-T-2006-526311 JP 2006-033446 A

  If the technique disclosed in Patent Document 1 described above is used, the maximum gain at which no oscillation occurs according to the installation environment can be obtained at the time when the repeater is installed and the provision of service is started.

  However, if the repeater installation environment changes during service provision and oscillation occurs, the gain is reduced. Thereafter, even when the installation environment is improved and the gain can be increased, the service is continued to be provided with the decreased gain.

  Accordingly, there is a problem that the service providing range is narrowed and the service level for the user is lowered.

  Further, if the technique disclosed in Patent Document 2 described above is used, it is possible to avoid oscillation by canceling interference between antennas. However, this technique has problems such as a complicated circuit configuration of the repeater, an increase in the size of the apparatus, and an increase in power consumption.

  The present invention provides a repeater, a gain control method, and a program capable of providing a service with a maximum gain that does not cause oscillation while suppressing a decrease in service to a user without complicating a circuit configuration. The purpose is to provide.

In order to achieve the above object, a repeater according to the present invention has first and second antennas, amplifies a signal received by the first antenna, and the amplified signal is transmitted to the second antenna. A repeater that amplifies the signal received by the second antenna and transmits the amplified signal from the first antenna,
Whether the oscillation is occurring based on the power level of the signal received by the second antenna when the power level of the signal received by the first antenna is less than or equal to a predetermined first threshold value A new gain for amplifying the signal received by the second antenna is determined according to the result of the determination.

In order to achieve the above object, a gain control method of the present invention includes first and second antennas, amplifies a signal received by the first antenna, and the amplified signal is A gain control method in a repeater for transmitting from a second antenna, amplifying a signal received by the second antenna, and transmitting the amplified signal from the first antenna,
Whether the oscillation is occurring based on the power level of the signal received by the second antenna when the power level of the signal received by the first antenna is less than or equal to a predetermined first threshold value An oscillation determination process for determining whether or not
Gain determination processing for determining a new gain when a signal received by the second antenna is amplified according to the result of the determination.

In order to achieve the above object, a program according to the present invention includes first and second antennas, amplifies a signal received by the first antenna, and converts the amplified signal to the second antenna. A repeater that transmits from the first antenna, amplifies the signal received by the second antenna, and transmits the amplified signal from the first antenna.
Whether the oscillation is occurring based on the power level of the signal received by the second antenna when the power level of the signal received by the first antenna is less than or equal to a predetermined first threshold value An oscillation judgment function to judge whether or not
In accordance with the result of the determination, a gain determination function for determining a new gain when a signal received by the second antenna is amplified is realized.

  According to the present invention, when the power level of the signal received by the first antenna is equal to or lower than the predetermined first threshold, the oscillation is based on the power level of the signal received by the second antenna. Determine if is happening. Then, a new gain for amplifying the signal received by the second antenna is determined according to the determination result.

  As a result, when the power level of the uplink signal is low, that is, when the user is not within the service providing range, the gain when the downlink signal is amplified is set to the maximum gain within the range where oscillation does not occur. Is possible. Therefore, it is possible to provide the service with the maximum gain that does not cause oscillation while preventing the service from being deteriorated without complicating the circuit configuration.

It is a block diagram which shows the structure of one Embodiment of the mobile communication system to which the repeater of this invention is applied. FIG. 2 is a block diagram illustrating an example of a configuration of a downlink amplification unit illustrated in FIG. 1. It is a block diagram which shows an example of a structure of the control part shown in FIG. 4 is a flowchart for explaining an operation of determining a gain when a repeater amplifies a downlink signal in the mobile communication system shown in FIGS.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an embodiment of a mobile communication system to which a repeater of the present invention is applied.

  As shown in FIG. 1, the mobile communication system according to the present embodiment includes a repeater 10, a base station 20, and a mobile station 30 owned by a user of a mobile communication carrier having the mobile communication system. ing.

  In this embodiment, one base station and one mobile station are provided, but the number of base stations and mobile stations is not limited to one.

  The repeater 10 includes a downlink amplifying unit 11 that amplifies the downlink signal, an uplink amplifying unit 12 that amplifies the uplink signal, a control unit 13, duplexers 14 and 15, and a base serving as a second antenna. A station-side antenna 16, a mobile station-side antenna 17 that is a first antenna, a downlink detector 18 that is a second detection means, and an uplink detector 19 that is a first detection means are provided. .

  The duplexer 14 separates the downlink signal received by the base station side antenna 16 and the amplified uplink signal transmitted from the base station side antenna 16.

  The duplexer 15 separates the uplink signal received by the mobile station side antenna 17 and the amplified downlink signal transmitted from the mobile station side antenna 17.

  The base station antenna 16 receives the downlink signal transmitted from the base station 20. Further, the base station side antenna 16 receives the uplink signal amplified by the uplink amplifying unit 12 via the duplexer 14 and transmits it to the base station 20.

  The mobile station side antenna 17 receives the uplink signal transmitted from the mobile station 30. Further, the mobile station side antenna 17 receives the downlink signal amplified by the downlink amplifying unit 11 via the duplexer 15 and transmits it to the mobile station 30.

  FIG. 2 is a block diagram showing an example of the configuration of the downlink amplifying unit 11 shown in FIG.

  As shown in FIG. 2, the downlink amplifying unit 11 illustrated in FIG. 1 includes a downlink amplifier 111 and a downlink ATT (ATTenuator) 112.

  The downlink amplifier 111 starts and stops the amplification of the downlink signal by turning on / off the power of the downlink amplifier 111 according to the instruction indicated by the control signal output from the control unit 13.

  The downlink ATT 112 is a circuit for adjusting a gain when a downlink signal is amplified, and has a plurality of setting values. This set value is changed according to the instruction indicated by the control signal output from the control unit 13. Thereby, the gain at the time of amplifying a downlink signal changes.

  Referring to FIG. 1 again, the uplink amplifying unit 12 has the same configuration as that of the downlink amplifying unit 11 shown in FIG. 2, and is not shown here, but includes an uplink amplifier and an uplink ATT. Yes. Compared with the downlink amplifier 111 and the downlink ATT 112, the uplink amplifier and the uplink ATT have the same operation except that the signal to be amplified becomes an uplink signal.

  The downlink detector 18 detects the power level of the downlink signal received by the base station side antenna 16.

  The uplink detector 19 detects the power level of the uplink signal received by the mobile station side antenna 17.

  FIG. 3 is a block diagram illustrating an example of the configuration of the control unit 13 illustrated in FIG. 1.

  As shown in FIG. 3, the control unit 13 shown in FIG. 1 monitors the control of the repeater 10 and the operation for monitoring the state of the repeater 10, and the control of the repeater 10 and the state of the repeater 10. A memory 132 for storing a program and a threshold value and a clock timer unit 133. The threshold will be described later.

  The memory 132 is a first threshold value for determining whether or not the mobile station 30 exists within the service providing range of the repeater 10 from the power level of the uplink signal detected by the uplink detector 19. The determination threshold value is stored. Further, the memory 132 stores an oscillation determination threshold value that is a second threshold value for determining whether oscillation is occurring based on the power level of the downlink signal detected by the downlink detector 18.

  The calculation unit 131 starts and stops amplification in the downlink amplification unit 11 and the uplink amplification unit 12 by outputting a control signal to the downlink amplification unit 11 and the uplink amplification unit 12. Further, the arithmetic unit 131 outputs a control signal to the downlink amplifying unit 11 and the uplink amplifying unit 12, thereby changing a gain when the downlink amplifying unit 11 and the uplink amplifying unit 12 perform amplification. Further, the calculation unit 131 acquires the power levels of the downlink signal and the uplink signal detected by the downlink detector 18 and the uplink detector 19. In addition, the arithmetic unit 131 compares the power level of the uplink signal detected by the uplink detector 19 with the user presence / absence determination threshold value stored in the memory 132 at a predetermined cycle. If the power level of the detected uplink signal is equal to or lower than the user presence / absence determination threshold value as a result of the comparison, it is determined that there is no user within the service providing range, and the calculation unit 131 amplifies the downlink signal. Change the gain. Specifically, the operation unit 131 increases the set value of the downlink ATT 112 from a predetermined minimum value, and the downlink detector in a state where amplification is being performed in the downlink amplification unit 11 and a state where it is stopped. The power level difference detected at 18 is calculated. Then, the calculated difference is compared with the oscillation determination threshold value stored in the memory 132. If oscillation is occurring and amplification is started, signal wraparound occurs between the base station side antenna 16 and the mobile station side antenna 17. As a result, the power level of the signal rises to the saturation level. Therefore, it is possible to determine whether or not oscillation has occurred based on the difference in signal power level between the state where amplification is being performed and the state where amplification is being stopped. The calculation unit 131 repeats this operation, and determines a new gain for amplifying the downlink signal based on the gain when the calculated difference is equal to or less than the oscillation determination threshold value. Details of the operation of changing the gain when amplifying the downlink signal will be described in an operation flow described later.

  The configuration of the mobile communication system according to the present embodiment has been described above. However, the configurations of the base station 20 and the mobile station 30 shown in FIG. 1 are well known to those skilled in the art, and directly with the present invention. Does not matter. Therefore, description of the configurations of the base station 20 and the mobile station 30 is omitted here.

  Below, the operation | movement which determines the gain at the time of the repeater 10 amplifying a downlink signal in the mobile communication system comprised as mentioned above is demonstrated.

  FIG. 4 is a flowchart for explaining an operation of determining a gain when the repeater 10 amplifies a downlink signal in the mobile communication system shown in FIGS.

  First, when the power is turned on, the repeater 10 performs initial settings necessary for the operation of the repeater 10 and the like.

  When the initial setting or the like is completed, the calculation unit 131 of the control unit 13 outputs a signal to the downlink amplification unit 11 to set the setting value of the downlink ATT 112 to a predetermined minimum value (step S1). Thereby, the gain at the time of amplifying a downlink signal becomes a predetermined maximum value.

  Next, the calculation unit 131 outputs a control signal to the downlink amplification unit 11 to turn off the power of the downlink amplifier 111 (step S2). Thereby, amplification of the downlink signal is stopped.

  Next, the downlink detector 18 detects the power level of the downlink signal (step S3). That is, here, the power level of the downlink signal in a state where the amplification of the downlink signal is stopped in the downlink amplifier 11 is detected.

  And the calculating part 131 acquires the power level of the downlink signal detected in step S3 from the downlink detector 18, and memorize | stores the acquired power level.

  Next, the arithmetic unit 131 outputs a control signal to the downlink amplifying unit 11 to turn on the power of the downlink amplifier 111 (step S4). Thereby, the amplification of the downlink signal is started.

  Next, the downlink detector 18 detects the power level of the downlink signal (step S5). That is, here, the power level of the downlink signal in a state where the downlink amplification unit 11 is executing amplification of the downlink signal is detected.

  Next, the computing unit 131 calculates a difference between the power level detected in step S3 and the power level detected in step S5 (step S6).

  Then, the calculation unit 131 determines whether or not the power level difference calculated in step S6 is larger than the oscillation determination threshold value stored in the memory 132 (step S7).

  If the result of determination in step S7 is that the difference in power level calculated in step S6 is greater than the oscillation determination threshold, the operation unit 131 determines whether or not the gain for amplifying the downlink signal is a predetermined minimum value. Is confirmed (step S8). If the difference in power level is larger than the oscillation determination threshold, it is determined that oscillation is occurring.

  If the gain in amplifying the downlink signal is not a predetermined minimum value as a result of the confirmation in step S8, the arithmetic unit 131 outputs a control signal to the downlink amplifying unit 11 so that the downlink has a predetermined increase width. The set value of ATT 112 is increased (step S9). Thereby, the gain at the time of amplifying a downlink signal decreases. And it changes to operation | movement of step S2.

  Thereafter, the operations from Steps S2 to S7 described above are repeated, and it is determined whether or not oscillation has occurred. If oscillation has occurred, it is determined in step S8 whether the gain for amplifying the downlink signal is a predetermined minimum value. If the gain for amplifying the downlink signal is not the predetermined minimum value, the gain for amplifying the downlink signal is further decreased by further increasing the set value of the downlink ATT 112 in step S9. Let And it changes to the operation | movement of step S2 again.

  As described above, until it is determined in step S7 that oscillation is not occurring, or until it is determined in step S8 that oscillation is occurring even when the gain for amplifying the downlink signal is a predetermined minimum value, The operation is repeated.

  Here, if the result of determination in step S7 is that the difference in power level calculated in step S6 is less than or equal to the oscillation determination threshold value, it is determined that no oscillation has occurred, and the calculation unit 131 reduces downtime at this time. Based on the gain corresponding to the set value of the link ATT 112, a gain for amplifying the downlink signal is determined (step S10). Note that the determined gain is a gain obtained by adding an appropriate margin to the gain corresponding to the set value of the downlink ATT 112 at this time. The appropriate margin may be determined so that oscillation does not occur even when the power level varies.

  If the gain in amplifying the downlink signal is a predetermined minimum value as a result of the confirmation in step S8, the arithmetic unit 131 generates an alarm or the like although the circuit is not shown in FIG. (Step S11). This is because oscillation occurs even if the gain is a predetermined minimum value, and it is determined that normal operation is impossible. By generating an alarm or the like, the installation operator or the like of the repeater 10 is notified of this, and oscillation is avoided by changing the installation location of the base station side antenna 16 or the mobile station side antenna 17.

  After the gain is determined in step S10, the operation shifts to normal operation. Note that the gain when the uplink signal is amplified may be set to the same level as the gain determined in step S10, for example. As a result, the gain at the time of amplifying the uplink signal can be set to a gain that does not cause oscillation.

  After starting normal operation, the uplink detector 19 detects the power level of the uplink signal at a predetermined period (step S12).

  And the calculating part 131 determines whether the power level of the uplink signal detected in step S12 is larger than a user presence determination threshold value (step S13).

  If the power level of the detected uplink signal is greater than the user presence / absence determination threshold value as a result of the determination in step S13, normal operation is continued and the operation transitions to step S12. This is because it is determined that the mobile station 30 is within the service provision range of the repeater 10.

  On the other hand, as a result of the determination in step S13, when the detected power level of the uplink signal is equal to or less than the user presence / absence determination threshold, the process proceeds to step S1. That is, a new gain for amplifying the downlink signal is determined according to the operations of steps S2 to S9 described above. This is because it is determined that there is no problem even if the mobile station 30 does not exist within the service providing range of the repeater 10 and the gain at the time of amplifying the downlink signal is rapidly changed.

  As described above, in the present embodiment, when the power level of the uplink signal is equal to or lower than the user presence / absence determination threshold value, it is determined whether oscillation is occurring based on the power level of the downlink signal. Then, a new gain for amplifying the downlink signal is determined according to the determination result.

  As a result, when the power level of the uplink signal is low, that is, when the user is not within the service providing range, the gain when the downlink signal is amplified is set to the maximum gain within the range where oscillation does not occur. Is possible. Specifically, for example, it is possible to reset the gain at the time of amplifying the downlink signal to a large value in a time zone such as at night when the mobile station 30 does not exist within the service provision range of the repeater 10.

  Therefore, it is possible to provide the service with the maximum gain that does not cause oscillation while preventing the service from being deteriorated without complicating the circuit configuration.

  In the present embodiment, as shown in FIG. 1, a downlink detector 18 for detecting the power level of the downlink signal is provided between the duplexer 14 and the downlink amplifying unit 11. In addition, an uplink detector 19 for detecting the power level of the uplink signal is provided between the duplexer 15 and the uplink amplifying unit 12. However, such a configuration is not necessarily required, and a detector may be provided at an arbitrary position on a path through which each signal passes. Further, without providing a detector, each signal may be demodulated at an arbitrary position on the path through which each signal passes, and the power level of each signal may be detected from the demodulated information.

  In the present embodiment, the downlink amplifying unit 11 starts and stops amplification by turning on and off the power supply of the downlink amplifier 111. Instead of such a method, amplification may be started and stopped by providing a switch before or after the downlink amplifier 111 and turning the switch ON / OFF.

  In the present invention, the processing in the repeater is recorded on a recording medium that can be read by the repeater, in addition to what is realized by the dedicated hardware described above. The program recorded in (1) may be read by a repeater and executed. The recording medium that can be read by the repeater refers to a transfer medium such as a flexible disk, a magneto-optical disk, a DVD, and a CD, as well as an HDD built in the repeater.

DESCRIPTION OF SYMBOLS 10 Repeater 11 Downlink amplification part 12 Uplink amplification part 13 Control part 14,15 Duplexer 16 Base station side antenna 17 Mobile station side antenna 18 Downlink detector 19 Uplink detector 20 Base station 30 Mobile station 111 Downlink amplifier 112 Downlink ATT
131 arithmetic unit 132 memory 133 clock timer unit

Claims (9)

Having a first antenna and a second antenna, amplifying the signal received by the first antenna, transmitting the amplified signal from the second antenna, and by the second antenna A repeater for amplifying a received signal and transmitting the amplified signal from the first antenna;
Whether the oscillation is occurring based on the power level of the signal received by the second antenna when the power level of the signal received by the first antenna is less than or equal to a predetermined first threshold value A repeater that determines whether or not and determines a new gain when a signal received by the second antenna is amplified according to a result of the determination. The repeater according to claim 1, wherein
First detection means for detecting a power level of a signal received by the first antenna;
Second detection means for detecting a power level of a signal received by the second antenna;
An amplifying unit for amplifying a signal received by the second antenna;
A control unit for controlling the operation when amplifying the signal in the amplification unit,
The control unit, when the power level detected by the first detection means is less than or equal to the first threshold, while reducing the gain when amplifying the signal in the amplification unit from a predetermined maximum value, A difference between the power levels detected by the second detection means between a state in which amplification of the signal is being executed and a state in which the amplification is stopped in the amplification unit is calculated, and the calculated difference is a second predetermined value. A repeater that determines whether the new gain is based on a gain when the calculated difference is equal to or smaller than the second threshold as a result of the determination. The repeater according to claim 1 or 2,
The first antenna is an antenna that receives a signal transmitted from a mobile station in a mobile communication system,
The second antenna is a repeater that is an antenna that receives a signal transmitted from a base station in the mobile communication system. Having a first antenna and a second antenna, amplifying the signal received by the first antenna, transmitting the amplified signal from the second antenna, and by the second antenna A gain control method in a repeater for amplifying a received signal and transmitting the amplified signal from the first antenna,
Whether the oscillation is occurring based on the power level of the signal received by the second antenna when the power level of the signal received by the first antenna is less than or equal to a predetermined first threshold value An oscillation determination process for determining whether or not
And a gain determination process for determining a new gain when a signal received by the second antenna is amplified according to the determination result. The gain control method according to claim 4, wherein
The oscillation determination process includes
When the power level of the signal received by the first antenna is less than or equal to the first threshold, the gain at the time of amplifying the signal received by the second antenna is decreased from a predetermined maximum value. However, a process of calculating a difference in power level of the signal received by the second antenna between a state in which amplification of the signal received by the second antenna is being executed and a state in which the signal is stopped;
Determination processing for determining whether or not the calculated difference is greater than a predetermined second threshold,
The gain determination process is a gain control method in which the new gain is determined based on a gain when the calculated difference becomes equal to or less than the second threshold as a result of the determination in the determination process. The gain control method according to claim 4 or 5,
The first antenna is an antenna that receives a signal transmitted from a mobile station in a mobile communication system,
The gain control method, wherein the second antenna is an antenna that receives a signal transmitted from a base station in the mobile communication system. Having a first antenna and a second antenna, amplifying the signal received by the first antenna, transmitting the amplified signal from the second antenna, and by the second antenna A repeater for amplifying the received signal and transmitting the amplified signal from the first antenna;
Whether the oscillation is occurring based on the power level of the signal received by the second antenna when the power level of the signal received by the first antenna is less than or equal to a predetermined first threshold value An oscillation judgment function to judge whether or not
A program for realizing a gain determination function for determining a new gain when a signal received by the second antenna is amplified according to the determination result. The program according to claim 7,
The oscillation determination function is
When the power level of the signal received by the first antenna is less than or equal to the first threshold, the gain at the time of amplifying the signal received by the second antenna is decreased from a predetermined maximum value. However, a function of calculating a difference in power level of the signal received by the second antenna between a state in which amplification of the signal received by the second antenna is being executed and a state of being stopped
A determination function for determining whether the calculated difference is greater than a predetermined second threshold,
The gain determination function is a program for determining the new gain based on a gain when the calculated difference becomes equal to or smaller than the second threshold as a result of the determination by the determination function. In the program according to claim 7 or 8,
The first antenna is an antenna that receives a signal transmitted from a mobile station in a mobile communication system,
The second antenna is a program that is an antenna that receives a signal transmitted from a base station in the mobile communication system.

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