JP2006086774A - Digital radio device and receiving method therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio device capable of easily controlling the attenuation amount of a variable attenuator to receive reception radio waves, and a receiving method in the digital radio device. <P>SOLUTION: The digital radio device 10 is provided with an amplifier 12 for amplifying a reception radio wave from an antenna 11; the variable attenuator 13 for receiving the reception radio wave amplified in the amplifier 12, and having an attenuation amount set at a normal value so that an excessive input in a radio device 15 may be prevented; the receiver 15 to which a reception radio wave is inputted from the variable attenuator 13; first attenuation amount control means 16, 17 for outputting attenuation amount control signals to the variable attenuator 13 for gradually changing the attenuation amount of the variable attenuator 13 only once for one speech in normal operation in response to the strength of the radio wave outputted from the variable attenuator 13; and second attenuation amount control means 16, 18 for manually changing the attenuation amount of the variable attenuator 13 in urgent operation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a digital radio and a reception method in the digital radio, and more particularly, in a digital radio and a digital radio suitable for improving reception performance in a commercial digital base station radio used in an electric power company or the like. It relates to the receiving method.

  Traditionally, a digital base station radio for commercial use, which has been used for communication when an electric power company performs its business or business, may not perform demodulation correctly due to strong received radio waves. Attenuators (attenuators) are inserted in the previous stage to reduce the level of received radio waves.

In order to avoid an increase in the number of parts when an attenuator is provided in front of the amplifier and complicated level control in the control unit, a path for switching in the antenna switch is normally connected to the reception side during reception. However, in the case of a high level input, the digital wireless device that switches the connection to the transmission side and connects the output signal from one terminal of the directional coupler to the reception input unit with a switch is shown in the following patent document 1 is disclosed.
JP 2003-8468 A

However, in order to avoid complicated level control in a commercial digital base station radio, if the attenuation of the attenuator inserted after the amplifier is fixed, the attenuation of the attenuator will attenuate strong received radio waves. Therefore, there is a problem that the received radio wave from the mobile station that has moved near the boundary of the service area where the intensity of the received radio wave becomes small is attenuated so that it cannot be received.
In addition, when an emergency disaster occurs, not only strong received radio waves from mobile stations in the service area, but also extremely weak received radio waves from mobile stations entering the adjacent service area can be received. However, there is a problem that such a request cannot be met if the attenuation of the attenuator is fixed.
Furthermore, there is a problem that the amount of attenuation of the attenuator cannot be further increased when it cannot be demodulated correctly due to a stronger received radio wave than expected.

  An object of the present invention is to provide a digital radio device and a receiving method in the digital radio device that can receive received radio waves by simply controlling the attenuation amount of a variable attenuator.

The digital radio of the present invention has an antenna (11) for receiving radio waves from a mobile station, an amplifier (12) for amplifying radio waves received from the antenna, and a radio wave received by the amplifier, and , A variable attenuator (13) whose attenuation is set to a normal value so that radio waves from the mobile station do not become excessive input at the receiver (15), and a receiver to which received radio waves are input from the variable attenuator ( 15) and an attenuation amount control signal for changing the attenuation amount of the variable attenuator stepwise according to the intensity of the received radio wave output from the variable attenuator only once per call during normal operation. First attenuation amount control means (16, 17) for outputting to the variable attenuator, and second attenuation amount control means (16, 18) for manually changing the attenuation amount of the variable attenuator during an emergency operation. ).
Here, the first attenuation control means outputs the attenuation control signal to the variable attenuator during normal operation, then monitors the RSSI signal output from the receiver, and inputs it to the receiver. If it is detected that the intensity of the received radio wave is still excessive, the attenuation amount of the variable attenuator may be fixed to a constant value.
When the first attenuation control means terminates the call with the mobile station, an attenuation control signal for changing the attenuation of the variable attenuator to a normal value is passed to the variable attenuator after a predetermined time has elapsed. It may be output.
The first attenuation control means outputs one of a plurality of attenuation control signals for changing the predetermined attenuation of the variable attenuator stepwise from the variable attenuator. The selected attenuation control signal may be output to the variable attenuator.
Using the second attenuation amount control means, one of a plurality of other attenuation amount control signals for changing the predetermined attenuation amount of the variable attenuator stepwise is manually selected, The other selected attenuation control signal may be input to the variable attenuator.
During emergency operation, after manually changing the attenuation amount of the variable attenuator, if the intensity of the received radio wave input to the receiver is still excessively large, a receiver excessive input that outputs a receiver excessive input warning signal is output. An alarm signal output means (17) and an alarm lamp (19) that is turned on when the receiver excessive input alarm signal is input from the receiver excessive input alarm signal output means may further be provided.

The receiving method in the digital radio of the present invention includes a step (S11) of receiving a radio wave from a mobile station by an antenna (11), and an amplifier (12) for amplifying the radio wave received from the antenna during normal operation. A step of changing the attenuation amount of the variable attenuator (13) for attenuating the input received radio wave stepwise only once per call according to the intensity of the received radio wave output from the variable attenuator (S13) In an emergency operation, the step of manually changing the attenuation amount of the variable attenuator (S21, S22), and when the communication with the mobile station is finished, the attenuation amount of the variable attenuator And a step of changing to a value (S15, S16).
Here, during normal operation, after changing the attenuation of the variable attenuator, the RSSI signal output from the receiver is monitored, and if the intensity of the received radio wave input to the receiver is still excessive, The method may further comprise a step (S14) of fixing the attenuation amount of the variable attenuator to a constant value.
A step of outputting a receiver excessive input warning signal when the intensity of the received radio wave input to the receiver is still excessive after the amount of attenuation of the variable attenuator is manually changed during an emergency operation (S23); When the receiver excessive input alarm signal is inputted, the alarm lamp (19) is turned on (S24). When the alarm lamp is turned on, the attenuation amount of the variable attenuator is manually adjusted as necessary. A step (S25) of changing may be further included.

The digital wireless device and the receiving method in the digital wireless device of the present invention have the following effects.
(1) During normal operation, the attenuation of the variable attenuator is changed stepwise only once per call according to the strength of the received radio wave. can do.
(2) If the intensity of the received radio wave input to the receiver during an emergency operation becomes excessive, the emergency call can be secured flexibly by manually changing the attenuation of the variable attenuator.
(3) During normal operation, after changing the attenuation amount of the variable attenuator, the RSSI signal output from the receiver is monitored, and if the intensity of the received radio wave input to the receiver is still excessive, By fixing the attenuation amount of the variable attenuator to a constant value, it is possible to easily cope with fluctuations in received radio waves within one call.
(4) When the call with the mobile station is completed, the call with the mobile station can always be started in the same reception state by changing the attenuation amount of the variable attenuator to the normal value after a predetermined time has elapsed.

  Variable attenuation that attenuates the received radio wave input through the amplifier that amplifies the received radio wave from the antenna during normal operation for the purpose of easily receiving the received radio wave by controlling the attenuation amount of the variable attenuator The attenuation of the attenuator is changed stepwise only once per call according to the strength of the received radio wave output from the variable attenuator, and the attenuation of the variable attenuator is changed manually during emergency operation. Realized by.

Embodiments of a digital wireless device and a receiving method in the digital wireless device of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic block diagram for explaining a digital radio according to an embodiment of the present invention. The digital radio 10 according to the present embodiment includes an antenna 11, an amplifier 12 (low noise amplifier), a variable attenuator 13, a distributor 14, a receiver 15, a switch 16, a detector 17, and a command. Device 18.

The antenna 11 receives radio waves from the mobile station and outputs the received radio waves to the amplifier 12.
The amplifier 12 amplifies the received radio wave input from the antenna 11. The gain of the amplifier 12 is set to a predetermined fixed value (for example, 22 dB) in consideration of the size of the service area covered by the digital radio device 10 so as not to be saturated even with a strong received radio wave. Is set.

  The variable attenuator 13 attenuates the received radio wave input from the amplifier 12. The amount of attenuation of the variable attenuator 13 can be changed in four stages of 0 dB, 10 dB, 15 dB, and 20 dB, and is set to a normal value (for example, 10 dB) when no radio wave is received (normal state). The attenuation amount of the variable attenuator 13 is changed based on a later-described first or second attenuation amount control signal input from the switcher 16 according to the intensity of the received radio wave.

The distributor 14 outputs a part of the received radio wave input from the variable attenuator 13 to the detector 17 and outputs the rest to the receiver 15.
The receiver 15 demodulates the received signal based on the received radio wave input from the distributor 14 and outputs an RSSI signal indicating the intensity of the received radio wave to the detector 17.

The detector 17 detects the intensity of the received radio wave based on the received radio wave input from the distributor 14 and changes, for example, the attenuation amount of the variable attenuator 13 shown below stepwise based on the detection result. One of the four first attenuation control signals is selected.
(1) A first attenuation control signal for setting the attenuation of the variable attenuator 13 to 0 dB (2) A first attenuation control signal for setting the attenuation of the variable attenuator 13 to 10 dB (3) The variable attenuator 13 A first attenuation control signal that sets the attenuation to 15 dB. (4) A first attenuation control signal that sets the attenuation of the variable attenuator 13 to 20 dB.

Further, the detector 17 monitors the RSSI signal input from the receiver 15 and detects that the intensity of the received radio wave input to the receiver 15 is still excessive, the attenuation amount of the variable attenuator 13 during normal operation. Is selected as a constant value (for example, 20 dB), and a receiver excessive input warning signal is output to the command device 18 during an emergency operation.
Furthermore, when the detector 17 detects the end of the call based on the intensity of the received radio wave input from the distributor 14, the attenuation amount of the variable attenuator 13 is set to a normal value after a predetermined time (for example, 30 seconds) has elapsed. In order to return, the first attenuation amount control signal for selecting the attenuation amount of the variable attenuator 13 as 10 dB is selected.

The command device 18 outputs a second attenuation amount control signal for changing the attenuation amount of the variable attenuator 13 in a stepwise manner to the switcher 16, and the first and second attenuation amount control signals in the switcher 16. And a control signal for controlling switching between the normal operation mode and the emergency operation mode in the detector 17 is output to the switch 16 and the detector 17.
The switch 16 selects either the first attenuation control signal from the detector 17 or the second attenuation control signal from the command device 18 based on the control signal input from the command device 18. And output to the variable attenuator 13.

Hereinafter, the operation of the digital wireless device 10 of this embodiment (the reception method in the digital wireless device according to one embodiment of the present invention) will be described with reference to the flowcharts shown in FIGS.
(Normal operation)
First, the operation of the digital wireless device 10 during normal operation will be described with reference to FIG.
The person in charge uses the command device 18 to cause the switch 16 to select a first attenuation amount control signal from the detector 17 and to switch a control signal to switch the operation mode of the detector 17 to the normal operation mode. And output to the detector 17.

When radio waves from the mobile station are received by the antenna 11 (step S11), the received radio waves are amplified by the amplifier 12 by 22 dB (fixed value) and then input to the variable attenuator 13. Since the attenuation amount of the variable attenuator 13 is set to 10 dB (normal value) so as not to become an excessive input at the receiver 15, the received radio wave is attenuated by 10 dB by the variable attenuator 13 and input to the distributor 14. The
A part of the received radio wave is output to the detector 17 by the distributor 14 and the rest is output to the receiver 15 (step S12).
In the receiver 15, the received signal is demodulated based on the received radio wave input from the distributor 14, and an RSSI signal indicating the intensity of the received radio wave is output to the detector 17.

In the detector 17, the intensity of the received radio wave input from the distributor 14 is detected, and on the basis of the detection result, a first attenuation amount control signal for changing the attenuation amount of the variable attenuator 13 stepwise is obtained. Selected (step S13).
For example, the received radio wave intensity is divided into two ranges (for example, a first range that is less than a predetermined value and a second range that is greater than or equal to a predetermined value), and the received radio wave intensity is a value within the first range. For example, if the first attenuation control signal that selects 10 dB as the attenuation of the variable attenuator 13 is selected and the intensity of the received radio wave is in the second range, the attenuation of the variable attenuator 13 is set to 15 dB. A first attenuation control signal is selected.

  Here, the first attenuation control signal is selected only once in one call. That is, when one of the two first attenuation control signals described above is selected based on the intensity of the received radio wave input from the distributor 14 at the start of a call, the detector 17 thereafter distributes the distributor 14. The operation of detecting the intensity of the received radio wave input from is not performed. This is because, for example, in commercial mobile radio systems used by electric power companies, mobile stations rarely talk to base stations while moving, and the intensity of received radio waves fluctuates significantly during a single call. This is because the control of the variable attenuator 13 is simplified.

  However, after that, the detector 17 monitors the RSSI signal input from the receiver 15, and if it is detected that the intensity of the received radio wave input to the receiver 15 is still excessive, the variable attenuator 13. A first attenuation amount control signal for selecting the attenuation amount of 20 dB (a constant value) is selected (step S14). Thereby, the amount of attenuation of the variable attenuator 13 is fixed to the maximum value of 20 dB.

  The first attenuation control signal selected by the detector 17 is output to the variable attenuator 13 via the switch 16. As a result, the amount of attenuation in the variable attenuator 13 can be changed according to the intensity of the received radio wave, so that not only the strong received radio wave from the mobile station in the service area but also the boundary of the service area where the intensity of the received radio wave is reduced, for example. Received radio waves from mobile stations that have moved nearby can also be received.

  Thereafter, when 30 seconds (fixed time) elapses after the call from the mobile station ends (step S15), the attenuation of the variable attenuator 13 is returned to return the attenuation of the variable attenuator 13 to 10 dB (normal value). A first attenuation amount control signal with an amount of 10 dB is selected by the detector 17 and output to the variable attenuator 13 via the switch 16 (step S16). As a result, when there is a call from the mobile station thereafter, the received radio wave from the mobile station can be received with the attenuation amount of the variable attenuator 13 set to 10 dB (normal value).

(Emergency operation)
Next, the operation of the digital wireless device 10 during an emergency operation will be described with reference to FIG.
When an emergency disaster occurs, the person in charge causes the switch 16 to select the second attenuation amount control signal from the command device 18 and switch the detector 17 in order to switch the control right of the variable attenuator 13 to the command device 18 side. A control signal for switching the operation mode to the emergency operation mode is output from the command device 18 to the switch 16 and the detector 17 (step S21).

The person in charge has a second attenuation amount control signal for changing the attenuation amount of the variable attenuator 13 in four stages (for example, a second attenuation amount control signal for setting the attenuation amount of the variable attenuator 13 to 0 dB, a variable attenuation amount). A second attenuation control signal that sets the attenuation of the attenuator 13 to 10 dB, a second attenuation control signal that sets the attenuation of the variable attenuator 13 to 15 dB, and a second that sets the attenuation of the variable attenuator 13 to 20 dB. The attenuation amount of the variable attenuator 13 is changed by selecting one of the attenuation control signals) according to the location where the emergency disaster has occurred (step S22).
For example, if the person in charge selects the second attenuation amount control signal for setting the attenuation amount of the variable attenuator 13 to 0 dB, the second attenuation amount control signal is variably attenuated from the command device 18 via the switch 16. As a result, the attenuation of the variable attenuator 13 is changed from 10 dB (normal value) to 0 dB.

Thereafter, when radio waves from the mobile station are received by the antenna 11, the received radio waves are amplified by the amplifier 12 by 22 dB (fixed value) and then input to the variable attenuator 13. The received radio wave is attenuated by 0 dB by the variable attenuator 13 and then input to the distributor 14.
A part of the received radio wave is output to the detector 17 by the distributor 14 and the rest is output to the receiver 15.
In the receiver 15, the received signal is demodulated based on the received radio wave input from the distributor 14, and an RSSI signal indicating the intensity of the received radio wave is output to the detector 17.

Thereafter, the detector 17 monitors the RSSI signal input from the receiver 15, and if it is detected that the intensity of the received radio wave input to the receiver 15 is still excessive, a receiver indicating that fact. An excessive input warning signal is generated (step S23).
At this time, the detector 17 creates only the receiver excessive input warning signal in order to give priority to securing the call area. That is, even if it is detected that the intensity of the received radio wave input to the receiver 15 is excessive, the detector 17 does not operate to change the attenuation amount of the variable attenuator 13.

The receiver excessive input alarm signal generated by the detector 17 is output to the command device 18, and for example, the alarm lamp 19 provided in the command device 18 is turned on (step S24).
When the alarm lamp 19 is lit, the person in charge examines whether or not the amount of attenuation of the variable attenuator 13 should be changed in consideration of the reception state at the receiver 15. For example, if it is determined that the attenuation amount of the variable attenuator 13 should be changed to 15 dB, the person in charge selects the second attenuation amount control signal that sets the attenuation amount of the variable attenuator 13 to 15 dB. Then, the second attenuation amount control signal is output from the command device 18 to the variable attenuator 13 via the switch 16 to change the attenuation amount of the variable attenuator 13 to 15 dB (step S25).

In the above description, the detector 17 selects one of the four first attenuation control signals according to the intensity of the received radio wave from the distributor 14, but according to the RSSI signal from the receiver 15. May be selected. In this case, the distributor 14 may not be provided.
Further, although the attenuation amount of the variable attenuator 13 is controlled in four stages of 0 dB, 10 dB, 15 dB, and 20 dB, it may be controlled in five stages or six stages.
Further, the normal value of the attenuation amount of the variable attenuator 13 during normal operation is 10 dB, but a predetermined value may be used according to the size of the service area covered by the digital radio device 10.

  Furthermore, the detector 17 selects one of the four predetermined first attenuation control signals, but the four first attenuation values of the variable attenuator 13 are indicated by a difference from the normal value. An attenuation amount control signal is determined in advance, one of the four first attenuation amount control signals is selected, and the selected first attenuation amount control signal is transmitted via the switch 16 to the variable attenuator 13. May be output. In this case, the attenuation amount of the variable attenuator 13 is changed to a value obtained by subtracting only the value indicated by the first attenuation amount control signal from the normal value. The same applies to the second attenuation control signal.

  The case where the present invention is applied to a non-diversity digital radio device has been described above, but the present invention can also be applied to a diversity digital radio device. For example, in a diversity digital radio using two antennas, an amplifier and a variable attenuator may be provided on the output side of the two antennas, respectively, and the amount of attenuation of the variable attenuator may be controlled similarly.

  In addition, although the digital radio device 10 shown in FIG. 1 has only one receiver 15, in a distributed digital base station radio device such as an electric power company, the receiver is usually used as a receiver and a standby one. Two units are provided. Therefore, for example, a receiver switching switch may be provided between the distributor 14 and the two receivers so that the current receiver and the spare receiver can be switched.

  As described above, the digital radio of the present invention can be used for a distributed digital base station radio used in an electric power company or the like.

It is a schematic block diagram for demonstrating the digital radio by one Example of this invention. (Example 1) 4 is a flowchart for explaining an operation at the time of a normal operation of the digital radio device 10 shown in FIG. 1. (Example 1) 3 is a flowchart for explaining an operation during an emergency operation of the digital radio device 10 shown in FIG. 1. (Example 1)

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Digital radio device 11 Antenna 12 Amplifier 13 Variable attenuator 14 Divider 15 Receiver 16 Switcher 17 Detector 18 Command device 19 Alarm lamp S11-S16, S21-S25 Step

Claims (9)

An antenna (11) for receiving radio waves from a mobile station;
An amplifier (12) for amplifying radio waves received from the antenna;
A variable attenuator (13) in which the reception radio wave amplified by the amplifier is input and the attenuation is set to a normal value so that the radio wave from the mobile station does not become an excessive input at the receiver (15);
A receiver (15) to which received radio waves are input from the variable attenuator;
During normal operation, an attenuation amount control signal for changing the attenuation amount of the variable attenuator stepwise in accordance with the intensity of the received radio wave output from the variable attenuator only once per call. First attenuation amount control means (16, 17) for outputting to
A second attenuation control means (16, 18) for manually changing the attenuation of the variable attenuator during an emergency operation;
A digital wireless device comprising:   In the normal operation, the first attenuation control means outputs the attenuation control signal to the variable attenuator, monitors the RSSI signal output from the receiver, and receives the signal input to the receiver. 2. The digital radio according to claim 1, wherein when the intensity of the radio wave is still detected to be excessive, the attenuation of the variable attenuator is fixed to a constant value.   When the first attenuation amount control means ends the call with the mobile station, an attenuation amount control signal for changing the attenuation amount of the variable attenuator to a normal value is passed to the variable attenuator after a predetermined time has elapsed. 3. The digital radio according to claim 1, wherein the digital radio is output.   The first attenuation control means outputs one of a plurality of attenuation control signals for changing the predetermined attenuation of the variable attenuator stepwise from the variable attenuator. 4. The digital wireless device according to claim 1, wherein the digital radio device is selected according to the intensity of the received radio wave and outputs the selected attenuation control signal to the variable attenuator.   Using the second attenuation amount control means, one of a plurality of other attenuation amount control signals for changing the predetermined attenuation amount of the variable attenuator stepwise is manually selected, 5. The digital radio according to claim 1, wherein the other selected attenuation control signal is input to the variable attenuator. During emergency operation, after manually changing the attenuation amount of the variable attenuator, if the intensity of the received radio wave input to the receiver is still excessively large, a receiver excessive input that outputs a receiver excessive input warning signal is output. Alarm signal output means (17);
An alarm lamp (19) that is turned on when the receiver excessive input alarm signal is input from the receiver excessive input alarm signal output means;
The digital wireless device according to claim 1, further comprising: Receiving radio waves from the mobile station with the antenna (11) (S11);
During normal operation, the attenuation amount of the variable attenuator (13) for attenuating the received radio wave input via the amplifier (12) for amplifying the received radio wave from the antenna is set to the amount of the received radio wave output from the variable attenuator. A step (S13) of changing step by step only once per call according to the strength;
Manually changing the attenuation of the variable attenuator during emergency operation (S21, S22);
When a call with the mobile station is completed, after a predetermined time has elapsed, the step of changing the attenuation of the variable attenuator to a normal value (S15, S16);
A receiving method in a digital radio device.   During normal operation, after changing the attenuation amount of the variable attenuator, the RSSI signal output from the receiver is monitored, and if it is detected that the intensity of the received radio wave input to the receiver is still excessive, the variable 8. The receiving method in the digital radio according to claim 7, further comprising a step (S14) of fixing an attenuation amount of the attenuator to a constant value. A step of outputting a receiver excessive input warning signal when the intensity of the received radio wave input to the receiver is still excessive after the amount of attenuation of the variable attenuator is manually changed during an emergency operation (S23); ,
A step (S24) of lighting an alarm lamp (19) when the receiver excessive input alarm signal is input;
When the warning lamp is turned on, manually changing the attenuation amount of the variable attenuator as necessary (S25);
The reception method in a digital radio according to claim 7 or 8, further comprising: