KR100268362B1 - Method and apparatus of capability analysis for receiving antenna - Google Patents

Abstract

PURPOSE: A device for analyzing a receiving antenna capacity is provided to measure an intensity of a signal radiated from a same base station transmitting antenna by a receiving antenna in order to analyze a capacity of the receiving antenna. CONSTITUTION: A transmitter directional coupler branches a transmitting signal radiated from a transmitting antenna by a base station transmitter, and inputs the branched transmitting signal. A transmitter rectifier rectifies an output signal of the transmitter directional coupler. A receiver directional coupler branches a signal incoming to a receiving antenna from a same base station, and inputs the branched signal. An LNA(Low Noise Amplifier) amplifies an output signal of the receiver directional coupler. A mixer mixes the amplified signal with a local oscillator signal in order to perform a down conversion for the amplified signal as an IF(Intermediate Frequency). A band pass filter intercepts a signal, which is out of a band among the output signal of the mixer. An amplifier amplifies an output signal of the band pass filter. A receiver rectifier rectifies the amplified signal. A comparator compares the output signal of the transmitter rectifier with the output signal of the receiver rectifier.

Description

Receiver antenna performance analysis method and device

The present invention relates to an analysis apparatus for monitoring the reception antenna performance of a wireless subscriber station base station.

Conventional transmission antenna diagnostic methods include a method of comparing and measuring a ratio between traveling waves and reflected waves of a transmission signal radiated from a base station and a method of diagnosing using a VSWR (voltage standing wave ratio) measuring equipment. The former can be measured at any time during operation, but the latter can be diagnosed at the time of installation or interruption of the antenna.

Here, VSWR (Voltage Standing Wave Ratio) is as follows. If there are incident and reflected waves on the transmission line, the effective values of current and voltage are the two waves combined and stopped on the line in appearance, which is called standing wave. The ratio of the maximum and minimum voltage rms values of the standing wave amplitude is called the voltage standing wave ratio.

That is, VSWR = V _max / V _min = (travel wave voltage + echo wave voltage) (progress wave voltage-echo wave voltage).

On the other hand, the diagnostic method of the receiving antenna is as follows. In general, since there is no resource to transmit in the receiving antenna, it can be diagnosed in the same manner as the transmitting antenna by radiating an arbitrary signal to the receiving antenna, and can be diagnosed when installing the antenna using a VSWR meter.

However, random signal radiation may interfere with other operating system or other system in operation, which may cause problems in operation. Recently, the mobile communication system finds the time zone that users use the least, stops the operation, and radiates within a short time to diagnose. This method is undesirable because it may cause inconvenience to a small number of users since it may result in an interruption of operation. In addition, in case of wireless subscriber network, it should be avoided considering that it is a backbone communication network.

Accordingly, the present invention provides a method and apparatus for diagnosing a transmission antenna using a conventional technique, and a diagnosis of a reception antenna can always diagnose even during operation using a transmission signal of a synchronization station without using unnecessary signal emission. Has its purpose.

1 is a block diagram of a base station transmitter signal transmission unit;

2 is a diagram illustrating a transmission signal detector received from a base station receiver;

3 is a diagram showing a functional block diagram of an analysis apparatus;

4 is a diagram illustrating a variable to be compensated for when receiving antennas are diagnosed.

According to the present invention, instead of a method of radiating any signal, it is determined whether the antenna state is abnormal by measuring the intensity of the signal radiated from the synchronization station transmission antenna to the reception antenna. When the amount of incoming transmission signal is less than the reference value, it can be predicted that an abnormality has occurred in the antenna, and it can be determined how much the antenna state is by comparing the change amount.

In general, in a wireless communication system, the transmission and reception frequency bands are spaced to some extent for bidirectional communication, and it is impossible to measure only a synchronization station transmission signal in a base station receiver. Therefore, there is a need for a separate analysis device that blocks incoming signals from other systems and can detect only the transmission signal of a synchronization station. The device must be designed to the extent that it does not affect the system at all. The present invention further describes this apparatus.

First, the hardware configuration of the present invention will be described.

The present invention includes a directional coupler unit capable of detecting a transmission signal at a base station transceiver and an analysis apparatus capable of measuring the strength of a synchronization station transmission signal at a base station receiver. The analyzer consists of a superheterodyne block that converts the received transmission signal into an intermediate frequency (IF) band, a SAW bandpass filter, a rectifier, a comparator, and the like having a high cut-off characteristic.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a diagram illustrating a transmission signal detection unit in a base station transmitter and configured with a directional coupler. The signal measured at the front end of the coupler is output to the comparator end of the analyzer.

FIG. 2 is a diagram illustrating a synchronization station transmission signal detection unit received at a base station receiver and configured with a directional coupler. The signal measured at the front of the coupler is output to the input of the analyzer.

The receiver antenna may receive for signals in all bands. In order to diagnose the antenna condition, the WLL out-of-band signals must be cut off so that the correct antenna condition can be known. Therefore, in order to extract only the transmission signal of the synchronization station, a bandpass filter capable of passing only the transmission station of the synchronization station is required. With the current technology, it is practically impossible to implement a high frequency bandpass filter with a sharp cutoff characteristic. In the case of wireless subscriber networks, the band 2.3 to 2.4 GHz is used.

In order to solve this problem, the present invention uses a SAW filter having excellent blocking characteristics after converting a high frequency signal into a low IF frequency band.

In FIG. 3, the high frequency signal f _R received through the port B is amplified by a low noise amplifer (LNA) and then down-converted to the IF frequency f _I by a difference from the LO frequency f _L at the mixer stage. f _R -f _L = f _I ) and then out-of-band signals are blocked through the SAW Band Pass Filter. SAW has excellent cutoff characteristics and operates mainly in the low frequency band. The SAW bandpass signal passes through an amplifier for compensating for path loss and the like, and compares the rectified signal with the rectifier transmitter output signal PortA to determine the performance and state of the antenna.

Here, SAW (Surface Acoustic Wave) is as follows. SAW devices refer to vibration devices using waves that propagate the surface of piezoelectric materials that convert electrical energy into mechanical energy. The wave propagating through the surface of the piezoelectric material is called SAW.

Figure 4 describes the parameters to be compensated for in the receiver antenna diagnosis. Based on these variables, the receiving antenna diagnosis method is explained in detail.

By applying the variable of FIG. 4, the signal strength of the analysis device input terminal shown in FIG. 3 is as follows.

P _B = P _A -P _air -P _tx -P _rx (1)

Assuming that the transmitting antenna is normal (typically VSWR 1.5: 1 or less), when the receiving antenna is in a normal state, the strengths of the two inputs P _A and P _R of the analyzer comparator shown in FIG. To do this, it is necessary to define the total gain (G) of the circuits from the input of the analyzer to the input of the comparator. So we can derive

G = P _air + P _tx + P _rx (2)

P _A = P _R = R _B + G (3)

When the total gain of the analyzer is defined as described above, the gain between the amplifiers may be adjusted to compensate for the gap between the synchronization station transmission signal and the transmission signal received at the receiver. In addition, a preliminary survey of the surrounding environment should be carried out. For example, since the path loss due to the distance between the transmitting and receiving antennas and the length of the feeder line between the antenna of the base station and the system are not constant, the value of the correction parameters may be changed, so an adjustment terminal capable of varying the gain in the analyzer is needed. In addition, when the state of the receiving antenna changes, for example, when the receiving antenna VSWR value changes to 2.0: 1, it is necessary to data the free space loss value. That is, the antenna state must be badly forced to store the received values at that time.

The present invention provides a method for diagnosing a reception antenna state during operation by adding the above-described devices to a base station device. That is, assuming that the transmission antenna state is normal, the antenna state can be estimated by the port C output value of FIG.

The role of antenna is very important in the mobile communication and wireless subscriber network system where demand is increasing rapidly. Depending on the antenna performance and operation, the overall performance of the system can be influenced and furthermore, it is an important measure to judge the overall quality of service. In general, the antenna can determine the state accurately when installed, but it is almost impossible to detect the state during operation. In case of any abnormality during operation, there have been a lot of trial and error to inspect the parts except the antenna first and finally check the antenna condition to find the cause. In order to supplement these problems, various researches are being conducted. The present invention can solve the above problems, it is possible to economically and efficiently manage unmanned base stations. In addition, by implementing system stabilization, there is an excellent effect of achieving better service.

Claims (3)

The size of the transmission signal radiated to the transmission antenna is measured by branching at the base station transmitter, and the size of the signal which is transmitted to the receiving antenna of the same base station is measured by branching at the receiver. And analyzing the performance of the reception antenna by comparing the magnitude of the incoming signal. The directional coupler of the transmitter for branching and inputting the transmission signal radiated to the transmission antenna from the base station transmitter, the rectifier of the transmitter for rectifying the output signal of the directional coupler of the transmitter, and the transmission signal to the reception antenna of the same base station A mixer for mixing the incoming signal branched from the receiver to the receiver, an LNA for amplifying the output signal of the receiver's directional coupler, and a mixer for mixing the signal with a local oscillator to downconvert the amplified signal to an IF frequency. A mixer, a band pass filter for blocking out-of-band signals from the output signal of the mixer, an amplifier for amplifying the output signal of the band pass filter, a rectifier for a receiver for rectifying the amplified signal, and a transmitter Comparator for comparing the output signal of the rectifier and the output signal of the rectifier of the receiver The received antenna performance analysis device according to claim. The apparatus of claim 2, wherein the band pass filter is a surface acoustic wave (SAW) band pass filter.

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