JP4420779B2 - Receiving method in digital base station radio equipment distributed by diversity system - Google Patents

Description

The present invention relates to a reception method in a diversity- based digital base station radio apparatus for diversity use suitable for improving reception performance in a digital base station radio apparatus for distribution used in an electric power company or the like.

  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 radio 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.

SUMMARY OF THE INVENTION An object of the present invention is to provide a reception method in a diversity-based distributed digital base station radio capable of receiving received radio waves by simply controlling the attenuation amounts of the first and second variable attenuators. is there.

According to the present invention, there is provided a reception method in a diversity system- operated digital base station radio device which includes receiving a radio wave from a mobile station with the first and second antennas (31 ₁ , 31 ₂ ) (S31) and during normal operation. , the strength of the received radio wave that is output from the first amplifier (32 ₁₎ via a first variable attenuator for attenuating the received radio wave input (33 ₁₎ for amplifying a received radio wave from said first antenna And the received radio wave output from the second variable attenuator (33 ₂ ) that attenuates the received radio wave input via the _second amplifier (32 ₂ ) that amplifies the received radio wave from the second antenna. Compared with the strength, the attenuation amount of the first and second variable attenuators is selected from 0 dB, 10 dB, and 15 dB at the start of the call according to the strength of the received radio wave having the higher strength. Step to change (S33, S34) and, during normal operation, monitor the RSSI signal output from the receiver based on the combined received radio wave after changing the attenuation amounts of the first and second variable attenuators, When it is detected that the intensity of the received radio wave input to the receiver is still excessive, the step of fixing the attenuation amounts of the first and second variable attenuators to 20 dB (S35), and during the emergency operation, the first Steps for manually changing the attenuation amounts of the first and second variable attenuators (S41, S42), and when the communication with the mobile station is completed, after a predetermined time has elapsed, the first and second variable attenuators And a step of changing the attenuation to a normal value (S36, S37).

  During emergency operation, if the intensity of the received radio wave input to the receiver is still excessive after manually changing the attenuation amount of the first and second variable attenuators, an excessive receiver alarm signal is output. Step (S43), step (S44) to turn on the alarm lamp (39) when the receiver excessive input alarm signal is input, and if the alarm lamp is turned on, the first and A step of manually changing the attenuation amount of the second variable attenuator (S45) may be further included.

The receiving method in the diversity system distributed digital base station radio of the present invention has the following effects.
(1) During normal operation, the attenuation amount of the first and second variable attenuators is changed by first selecting and changing one of 0 dB, 10 dB, and 15 dB according to the strength of the received radio wave having the higher strength. The received radio waves can be received by simply controlling the attenuation amounts of the first and second variable attenuators.
(2) When 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 amounts of the first and second variable attenuators. be able to.
(3) During normal operation, after changing the attenuation amounts of the first and second variable attenuators, the RSSI signal of the composite received radio wave output from the receiver is monitored, and the received radio wave input to the receiver is monitored. If it is detected that the intensity is still excessive, this can be easily dealt with by fixing the attenuation amounts of the first and second variable attenuators to 20 dB .
(4) When the call with the mobile station is finished, the call with the mobile station is always started in the same reception state by changing the attenuation amounts of the first and second variable attenuators to normal values after a certain period of time. can do.

The purpose of being able to receive the received radio wave by simply controlling the attenuation amounts of the first and second variable attenuators is that the intensity of the received radio wave output from the first variable attenuator and the first The intensity of the received radio wave output from the second variable attenuator is compared , and the attenuation amounts of the first and second variable attenuators are selectively changed according to the intensity of the received radio wave having the higher intensity. At the time of emergency operation, it was realized by manually changing the attenuation amounts of the first and second variable attenuators.

Hereinafter, embodiments of a receiving method in a diversity-based distributed digital base station radio of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic block diagram for explaining a diversity-based distributed digital base station radio used in the present invention. Diversity 営配digital base station radios 30 (hereinafter, referred to as "digital radio 30".) According to this embodiment, the first and second antenna 311 and 312, first and second amplifiers 32 ₁ , 32 ₂ (low noise amplifier), first and second variable attenuators 33 ₁ , 33 ₂ , first and second distributors 34 ₁ , 34 ₂ , a receiver 35, and a switch 36 And a detector 37 and a command device 38.

The first and second antennas 31 ₁ and 31 ₂ receive radio waves from the mobile station and output the received radio waves to the first and second amplifiers 32 ₁ and 32 ₂ , respectively.
The first and second amplifiers 32 ₁ and 32 ₂ amplify the received radio waves input from the first and second antennas 31 ₁ and 31 ₂ , respectively. The gains of the first and second amplifiers 32 ₁ and 32 ₂ are determined in advance in consideration of the size of the service area covered by the digital radio 30 so that it is not saturated even with strong received radio waves. Is set to a fixed value (for example, 22 dB).

The first and second variable attenuators 33 ₁ and 33 ₂ attenuate the received radio waves input from the first and second amplifiers 32 ₁ and 32 ₂ , respectively. The attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ can be changed in four stages of 0 dB, 10 dB, 15 dB, and 20 dB, and are normal values in a state where no radio wave is received (normal state). (For example, 10 dB). Note that the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ are based on first or second attenuation amount control signals (described later) input from the switch 36 in accordance with the intensity of the received radio wave. Changed.

The first and second distributor 34 _1, 34 _2, a portion of the received radio wave that is inputted from the ₂ first and second variable attenuator 33 _1, 33 outputs to the detector 37, the remainder Output to the receiver 35.
The receiver 35 demodulates the received signal based on the combined received radio wave obtained by combining the received radio waves input from the first and second distributors 34 ₁ and 34 ₂ , and also indicates an RSSI signal indicating the intensity of the combined received radio wave. Is output to the detector 37.

Detector 37 compares the intensity of the received radio wave that is input from the first divider 34 ₁ and the intensity of the received radio wave that is input from the ₂ second distributor 34, the intensity is more received radio waves of large Three first attenuation amount control signals for detecting the intensity and changing the attenuation amounts of the first and second variable attenuators 33 ₁ , 33 ₂ shown below, for example, stepwise based on the detection result Select one of these.
(1) First attenuation control signal for setting the attenuation of the first and second variable attenuators 33 ₁ and 33 ₂ to 0 dB. (2) Attenuation of the first and second variable attenuators 33 ₁ and 33 ₂ . First attenuation control signal for setting the amount to 10 dB (3) First attenuation control signal for setting the attenuation of the first and second variable attenuators 33 ₁ and 33 ₂ to 15 dB

The detector 37 monitors the RSSI signal input from the receiver 35 and detects that the intensity of the received radio wave input to the receiver 35 is still excessive, and during normal operation, the first and second detectors 37 A first attenuation amount control signal for setting the attenuation amounts of the variable attenuators 33 ₁ and 33 ₂ to 20 dB is selected and output to the switch 36, and in the event of an emergency operation, a receiver excessive input alarm signal is output to the command device 38. .
Furthermore, when the detector 37 detects the end of the call based on the intensity of the received radio waves input from the first and second distributors 34 ₁ and 34 ₂ , the detector 37 In order to return the attenuation amounts of the first and second variable attenuators 33 ₁ , 33 ₂ to normal values, the first attenuation amount in which the attenuation amounts of the first and second variable attenuators 33 ₁ , 33 ₂ are 10 dB. A control signal is selected and output to the switch 36 .

The command device 38 outputs a second attenuation amount control signal for selectively changing the attenuation amounts of the first and second variable attenuators 33 ₁ , 33 ₂ to the switch 36 and also in the switch 36. A control signal for controlling selection of the first and second attenuation control signals and switching of the operation mode between the normal operation mode and the emergency operation mode in the detector 37 is output to the switch 36 and the detector 37.
The switch 36 selects one of the first attenuation control signal from the detector 37 and the second attenuation control signal from the command device 38 based on the control signal input from the command device 38. To the first and second variable attenuators 33 ₁ and 33 ₂ .

Hereinafter, the operation of the digital radio 30 according to the present embodiment (reception method in the distributed digital base station radio according to an embodiment of the present invention) will be described with reference to the flowcharts shown in FIGS.
(Normal operation)
First, the operation of the digital radio device 30 during normal operation will be described with reference to FIG.
The person in charge uses the command device 38 to cause the switch 36 to select a first attenuation control signal from the detector 37 and to switch a control signal to switch the operation mode of the detector 37 to the normal operation mode. And output to the detector 37.

When radio waves from the mobile station are received by the first and second antennas 31 ₁ and 31 ₂ (step S31), the received radio waves output from the first and second antennas 31 ₁ and 31 ₂ are the first After being amplified by 22 dB (fixed value) by the second and second amplifiers 32 ₁ and 32 ₂ , they are respectively input to the first and second variable attenuators 33 ₁ and 33 ₂ . Since the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ are set to 10 dB (normal value) so as not to be excessively input by the receiver 35, the two received radio waves are the first and second received radio waves. Are attenuated by 10 dB by the variable attenuators 33 ₁ and 33 ₂ and input to the first and second distributors 34 ₁ and 34 ₂ , respectively.

A part of the received radio wave output from the first variable attenuator 33 _{1 is} output to the detector 37 by the first distributor 34 ₁ , and the rest is output to the receiver 35. Similarly, the received radio wave output from the second variable attenuator 33 _2, the second distributor 34 _2, a portion is output to the detector 37, (steps remainder is output to the receiver 35 S32).

The detector 37 is compared with the intensity of the received radio wave that is input from the first divider 34 of the received radio wave that is input from _a strength and a second distributor 34 ₂ (step S33), who strength greater is the detected intensity of the received radio wave is based on the detection result, the first attenuation control signal for selectively changing the first and second variable attenuator 33 _1, 33 ₂ of the attenuation selected (Step S34).
Specifically, the attenuation amounts of the first and second variable attenuators are set to 0 dB, the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ in accordance with the intensity of the received radio wave having the higher intensity . The first attenuation control signal is selected to be either 10 dB or 15 dB.

In the detector 37, the above-mentioned three first signals are based on the intensity of the received radio wave having the higher intensity of the two received radio waves input from the first and second distributors 34 ₁ and 34 ₂ at the start of the call. When one of the attenuation control signals is selected, the intensity of the received radio wave having the higher intensity of the two received radio waves input from the first and second distributors 34 ₁ and 34 ₂ thereafter. The operation of detecting 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 to simplify the control of the first and second variable attenuators 33 ₁ and 33 ₂ .

The first attenuation control signal selected by the detector 37 is output to the first and second variable attenuators 33 ₁ and 33 ₂ via the switch 36. As a result, the attenuation amounts in the first and second variable attenuators 33 ₁ and 33 ₂ 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, for example, reception It is also possible to receive radio waves received from mobile stations that have moved near the boundary of the service area where the radio wave intensity is low.

In the receiver 35, the received signal is demodulated based on the combined received radio wave obtained by combining the received radio waves input from the first and second distributors 34 ₁ and 34 _2, and the RSSI indicating the intensity of the combined received radio wave is obtained. A signal is output to the detector 37.

The detector 37 monitors the RSSI signal input from the receiver 35, and when it is detected that the intensity of the received radio wave input to the receiver 35 is still excessive, the first and second variable values are detected. The first attenuation control signal for selecting the attenuation of the attenuators 33 ₁ and 33 ₂ as 20 dB is selected, and the attenuation of the first and second variable attenuators 33 ₁ and 33 ₂ is fixed to the maximum value of 20 dB. (Step S35).

Thereafter, for example, when 30 seconds (fixed time) elapses after the call from the mobile station ends (step S36), the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ are set to 10 dB (normal value). In order to return, a first attenuation control signal for setting the attenuation of the first and second variable attenuators 33 ₁ , 33 ₂ to 10 dB is selected by the detector 37, and the first and second variable attenuators 33 ₁ , 33 ₂ are selected via the switch 36. It is output to the second variable attenuators 33 ₁ and 33 ₂ (step S37). As a result, when there is a call from the mobile station thereafter, the attenuation amount of the first and second variable attenuators 33 ₁ and 33 ₂ is set to 10 dB (normal value), and the received radio wave from the mobile station is Can be received.

(Emergency operation)
Next, the operation of the digital wireless device 30 during an emergency operation will be described with reference to FIG.
When emergency disaster occurs, the person in charge, in order to switch the first and second variable attenuator 33 _1, 33 ₂ of the control to the instruction unit 38 side, the second damping from the command device 38 to the switch 36 A control signal for selecting the quantity control signal and switching the operation mode of the detector 37 to the emergency operation mode is output from the command device 38 to the switch 36 and the detector 37 (step S41).

The person in charge has a second attenuation amount control signal (for example, the first and second variable attenuators 33 ₁ for changing the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ in three stages. , 33 ₂ , a second attenuation amount control signal for setting the attenuation amount to 0 dB, a second attenuation amount control signal for setting the attenuation amounts of the first and second variable attenuators 33 ₁ , 33 ₂ to 10 dB, By selecting one of the second variable attenuators 33 ₁ , 33 ₂ as a second attenuation amount control signal that sets the attenuation amount to 15 dB according to the location where the emergency disaster has occurred, the first and The attenuation amounts of the second variable attenuators 33 ₁ and 33 ₂ are changed (step S42).
For example, if the person in charge selects a second attenuation amount control signal for setting the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ to 0 dB, the second attenuation amount control signal is transmitted to the command device. 38 to the first and second variable attenuators 33 ₁ and 33 ₂ via the switch 36, the attenuation amount of the first and second variable attenuators 33 ₁ and 33 ₂ is 10 dB (normally Value) to 0 dB.

Thereafter, when the radio wave from the mobile station is received by the first and second antenna 31 _1, 31 _2, the received radio wave that is output from the first and second antenna 31 _1, 31 _2, first and second After being amplified by 22 dB (fixed value) by the _two amplifiers 32 ₁ and 32 ₂ , they are respectively input to the first and second variable attenuators 33 ₁ and 33 ₂ . The two received radio waves are respectively attenuated by, for example, 0 dB by the first and second variable attenuators 33 ₁ and 33 ₂ and then input to the first and second distributors 34 ₁ and 34 ₂ , respectively.

A part of the received radio wave output from the first variable attenuator 33 _{1 is} output to the detector 37 by the first distributor 34 ₁ , and the rest is output to the receiver 35. Similarly, the received radio wave output from the second variable attenuator 33 _2, the second distributor 34 _2, a portion is output to the detector 37, the remainder is output to the receiver 35.

In the receiver 35, the received signal is demodulated based on the combined received radio wave obtained by combining the received radio waves input from the first and second distributors 34 ₁ and 34 _2, and the RSSI indicating the intensity of the combined received radio wave is obtained. A signal is output to the detector 37.

Thereafter, the detector 37 monitors the RSSI signal input from the receiver 35, and if it is detected that the intensity of the received radio wave input to the receiver 35 is still excessive, a receiver indicating that fact. An excessive input warning signal is generated (step S43).
At this time, the detector 37 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 35 is excessive, the detector 37 changes the attenuation amount of the first and second variable attenuators 33 ₁ and 33 ₂ . Does not work.

The receiver excessive input alarm signal generated by the detector 37 is output to the command device 38, and for example, the alarm lamp 39 provided in the command device 38 is turned on (step S44).
When the alarm lamp 39 is lit, the person in charge examines whether or not the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ should be changed in consideration of the reception state at the receiver 35. For example, when it is determined that the attenuation amount of the first and second variable attenuators 33 ₁ , 33 ₂ should be changed to 15 dB, the person in charge determines that the first and second variable attenuators 33 ₁ , 33 ₂ , The second attenuation amount control signal for setting the attenuation amount of 33 ₂ to 15 dB is selected, and this second attenuation amount control signal is sent from the command device 38 via the switch 36 to the first and second variable attenuators 33. _1, 33 by outputting to _2, change the first and second variable attenuator 33 _1, 33 ₂ of the attenuation to 15 dB (step S45).

In the above description, the detector 37 selects one of the three first attenuation control signals according to the intensity of the received radio wave from the first or second distributor 34 ₁ , 34 _2. Depending on the RSSI signal from the receiver 35, the selection may be made. In this case, the first and second distributors 34 ₁ and 34 ₂ may not be provided.
Further, although the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ are controlled in four stages of 0 dB, 10 dB, 15 dB, and 20 dB, they may be controlled in five stages or six stages.
Furthermore, although the normal value of the attenuation amount of the first and second variable attenuators 33 ₁ and 33 ₂ is 10 dB, a predetermined value is set according to the size of the service area covered by the digital radio device 30. Use it.

In the normal operation and the emergency operation described above, the detector 37 selects one of the four predetermined first attenuation control signals, but the first and second variable attenuators are selected. Four first attenuation control signals indicating the attenuation amounts of 33 ₁ and 33 ₂ by the difference from the normal value are determined in advance, and one of the four first attenuation control signals is selected. The selected first attenuation control signal may be output to the first and second variable attenuators 33 ₁ and 33 ₂ via the switch 36. In this case, the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ are changed to values obtained by subtracting the normal value from the value indicated by the first attenuation amount control signal. The same applies to the second attenuation control signal.

Further, in the normal operation, the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ are set to the same value according to the intensity of the received radio wave having the higher intensity. When the difference in intensity between the received radio waves received by the antennas 31 ₁ and 31 ₂ is large, the attenuation amounts of the first and second variable attenuators 33 ₁ and 33 ₂ are separately set according to the intensity of each received radio wave. You may make it set.

Further, the digital radio 30 shown in FIG. 1 has only one receiver 35. However, in a commercial digital base station radio such as a power company, the receiver is usually used as a receiver and a spare one. Two units are provided. Therefore, for example, a receiver changeover switch is provided between the first and second distributors 34 ₁ and 34 ₂ and the two receivers so that the current receiver and the spare receiver can be switched. It may be.

  As described above, the present invention can be used for a commercial 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) 2 is a flowchart for explaining an operation at the time of a normal operation of the digital wireless device shown in FIG. (Example 1) 3 is a flowchart for explaining an operation during an emergency operation of the digital wireless device shown in FIG. 1. (Example 1)

30 digital radio 31 _1, 31 ₂ antennas 32 _1, 32 ₂ amplifiers 33 _1, 33 ₂ the variable attenuator 34 _1, 34 ₂ distributor 35 receiver 36 switch 37 detector 38 commander 39 warning lamp S31 to S37, Steps S41 to S45

Claims (2)

Receiving the radio wave from the mobile station by the first and second antennas (31 ₁ , 31 ₂ ) (S31);
During normal operation, the signal is received from the first variable attenuator (33 ₁ ) that attenuates the received radio wave input via the _first amplifier (32 ₁ ) that amplifies the received radio wave from the first antenna. Output from the second variable attenuator (33 ₂ ) for attenuating the intensity of the radio wave and the received radio wave input via the _second amplifier (32 ₂ ) that amplifies the radio wave received from the second antenna. Compared with the intensity of the received radio wave, the attenuation amount of the first and second variable attenuators is set to any one of 0 dB, 10 dB, and 15 dB at the start of the call according to the intensity of the received radio wave having the higher intensity. Selecting and changing one (S33, S34);
During normal operation, the RSSI signal output from the receiver is monitored based on the combined received radio wave after changing the attenuation amounts of the first and second variable attenuators, and input to the receiver. When detecting that the intensity of the received radio wave is still excessive, a step of fixing the attenuation amounts of the first and second variable attenuators to 20 dB (S35);
Manually changing the attenuation amounts of the first and second variable attenuators during emergency operation (S41, S42);
When the call with the mobile station is completed, after a lapse of a certain time, changing the attenuation amounts of the first and second variable attenuators to normal values (S36, S37);
A receiving method in a diversity-based distribution digital base station radio, comprising: During emergency operation, if the intensity of the received radio wave input to the receiver is still excessive after manually changing the attenuation amount of the first and second variable attenuators, an excessive receiver input alarm signal is output. Performing step (S43);
A step (S44) of lighting an alarm lamp (39) when the receiver excessive input alarm signal is input;
When the alarm lamp is turned on, manually changing the attenuation amounts of the first and second variable attenuators as needed (S45);
The reception method in the diversity system distribution digital base station radio according to claim 1, further comprising: