KR100377794B1 - Apparatus for compensating mixer signal loss of BTS in a communication system - Google Patents

Abstract

The present invention relates to a mixer signal loss compensation device of a base station in a communication system to compensate for signal loss caused by temperature change in a frequency up / down converter and performance degradation of other active devices. The present invention relates to a frequency up / down converter. Changes in temperature and other degradation of active device performance in the downconverter will degrade the local driver level of the mixer, and the local driver level will significantly reduce the conversion loss of the mixer. Monitors the level and does not compensate for loss that changes slightly over time (when the local level is above the set level), and compensates for the level of the transmit intermediate frequency and transmit RF signal only when the local level decreases below the set level. Do it.

Description

Apparatus for compensating mixer signal loss of BTS in a communication system}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixer signal loss compensation device of a base station (BTS) in a communication system (mobile communication system, IS-2000 system, etc.), in particular, the performance of temperature change and other active elements in a frequency up / down converter. The present invention relates to a mixer signal loss compensation device of a base station in a communication system to compensate for signal loss caused by degradation.

More specifically, a change in temperature and other degradation of active device performance in the frequency up / down converter degrades the local driver level of the mixer, and a signal loss caused by a significant decrease in the conversion loss of the mixer due to the local driver level degradation. The present invention relates to a mixer signal loss compensation apparatus of a base station in a communication system to compensate for the loss.

In general, in a communication system (mobile communication system, IS-2000 system, etc.), the local level of the mixer in the up / down converter of the base station requires a fairly high level to improve the IMD, so that the local level generated from the voltage controlled oscillator (VCO) The signal is amplified using an amplifier composed of MMICs.

Most MMIC-configured amplifiers have a high mixer local level, with only 1dB compensation point available at the threshold.

Therefore, if the indoor base station and the outdoor base station are used for a long time, the local level of the mixer gradually decreases due to various deterioration of the performance of the device continuously used at the threshold, temperature change in the system, and ambient temperature change.

The gradual decrease of the local level gradually increases the compensation loss of the mixer, and at some point, the compensation loss increases greatly because the mixer operates at the local level.

However, when looking at the mixer stage of the base station applied to the conventional communication system, it consists only of a configuration that simply mixes the received signal or the transmitted signal with the frequency generated in the VCO, as it is well known that it does not compensate for the signal loss caused by long time use There was a downside.

Accordingly, the present invention is proposed to solve the above problems of the prior art,

It is an object of the present invention to provide a mixer signal loss compensation device of a base station in a communication system to compensate for signal loss caused by a temperature change in a frequency up / down converter and performance degradation of other active elements.

More specifically, a change in temperature and other degradation of active device performance in the frequency up / down converter degrades the local driver level of the mixer, and a signal loss caused by a significant decrease in the conversion loss of the mixer due to the local driver level degradation. The present invention provides a mixer signal loss compensation device of a base station in a communication system to compensate for the loss.

Mixer signal loss compensation apparatus of the base station in the communication system according to the present invention for achieving the above object,

In order to compensate for the loss of signal due to the increase of the compensation loss, the level of the local driver is monitored and no compensation is made for the loss (when the local level is higher than or equal to the setting level) that changes little over time. It only compensates for signal levels when they are reduced.

1 is a block diagram showing the overall configuration of the base station RF stage of the communication system to which the mixer signal loss compensation apparatus according to the present invention is applied,

FIG. 2 is a circuit diagram illustrating an example of each part in the signal loss compensator of FIG. 1.

<Description of the symbols for the main parts of the drawings>

200, 300 ..... First signal loss compensation unit

210, 310 ..... Coupler

220, 320 ..... Amplifier

230, 330 ..... Detector

240, 340 ..... Comparator

251, 351 ..... the first RF switch

252, 352 ..... 2nd RF switch

1 is a block diagram showing the overall configuration of a base station apparatus RF stage of a communication system to which a mixer signal loss compensation apparatus according to the present invention is applied.

Reference numeral 101 denotes a first low pass filter (LPF) for low pass filtering the input transmission intermediate frequency IF, and reference numeral 102 denotes amplifying the intermediate frequency output from the first low pass filter 101 to a predetermined level. Reference numeral 103 denotes a first amplifier PAD for tracking a signal output from the first amplifier 102, and reference numeral 104 denotes a first voltage controlled oscillator for generating a local signal. Reference numeral 105 denotes a second low pass filter for low-pass filtering the local signal output from the first voltage controlled oscillator 104, and reference numeral 106 amplifies the output signal of the second low pass filter 105 to a predetermined level. A second amplifier is shown.

Reference numeral 107 denotes a second pad portion for tracking the signal output from the second low pass filter 106, and reference numeral 108 denotes a transmission IF signal and the second pad output from the first pad portion 103. Reference numeral 109 denotes a first mixer for mixing the local signals output from the unit 107, reference numeral 109 denotes a third pad unit for tracking the signal output from the first mixer 108, and reference numeral 110 denotes the third mixer. A third low pass filter for low-pass filtering the IF signal output from the pad unit 109 is shown, and reference numeral 111 represents a third amplifier for amplifying the intermediate frequency output from the third low pass filter 110 to a predetermined level.

Also, reference numeral 200 denotes a first signal loss compensator for compensating for a loss of a signal due to an increase in conversion loss of the first mixer 108.

In addition, reference numeral 112 denotes a first band filter for filtering the signal output from the first signal loss compensator 200 to a set band, and reference numeral 113 denotes an IF signal output from the first band filter 113. Denotes a fourth pad portion for tracking the signal, reference numeral 114 denotes a second voltage controlled oscillator for generating a local signal for generating a second transmission high frequency for generating a local frequency for frequency up-conversion, and reference numeral 115 denotes the A fourth low pass filter for low-pass filtering the local signal generated by the second voltage controlled oscillator 115, and reference numeral 116 denotes a fourth amplifier for amplifying the signal output from the fourth low pass filter 115 to a predetermined level. Indicates.

In addition, reference numeral 117 denotes a fifth pad portion for tracking a local signal output from the fourth amplifier 116, and reference numeral 118 denotes a transmission intermediate frequency output from the fourth pad portion 113 and the fifth pad portion. A second mixer which mixes the local signal output from the pad unit 117 and up-converts the RF signal into an RF signal, and reference numeral 119 denotes a sixth pad unit for tracking the RF signal output from the second mixer 118. Reference numeral 120 denotes a fifth low pass filter for low-pass filtering the RF signal output from the sixth pad unit 119, and reference numeral 121 denotes a predetermined level of the RF signal output from the fifth low pass filter 120. Denotes a fifth amplifier to be amplified.

Also, reference numeral 300 denotes a second signal loss compensator for compensating for signal loss due to an increase in conversion loss of the second mixer 118, and reference numeral 122 is output from the second signal loss compensator 300. A second band filter for band filtering a signal to be used.

The operation of the mixer signal loss compensator according to the present invention configured as described above will be described in detail with reference to FIG. 2.

The mixer signal loss compensator according to the present invention can be applied to both an RF receiver and an RF transmitter of a base station, and can be applied to both a communication system using an RF signal. Only one example is applied to.

First, the intermediate frequency IF input to the RF transmitter is low-pass filtered by the first low pass filter 101, then amplified to a predetermined level by the first amplifier 102, and tracking is performed through the first pad unit 103. After it is made, it is input to the first mixer 108.

In this case, the local signal Tx_IF_LO output from the first voltage controlled oscillator 104 is low-pass filtered by the second low pass filter 104, amplified to a predetermined level by the second amplifier 106, and then the first signal loss compensator ( It is transmitted to the second pad portion 107 via the coupler 210 in the 200. The second pad unit 107 tracks the local signal transmitted, and the local signal thus tracked is transmitted to the first mixer 108.

The first mixer 108 outputs an intermediate frequency by mixing two signals transmitted as described above, that is, a transmission intermediate frequency and a local signal, and the output intermediate frequency is transmitted by the third pad unit 109. Tracking is performed, low pass filtered by the third low pass filter 109, amplified to a predetermined level by the third amplifier 111, and then transmitted to the attenuation module 250 in the first signal loss compensator 200.

The first signal loss compensator 200 detects the level of the local signal output from the first voltage controlled oscillator 104 while the transmission IF signal is processed through such a path, and detects the level of the detected local signal. Accordingly, the signal loss of the first mixer 108 is compensated.

In more detail, the first signal loss compensator 200 may include a coupler 210 coupling a local signal output from the second amplifier 106 and a coupling output from the coupler 210. An amplifier 220 for amplifying the signal to a predetermined level, a detector 230 for detecting a signal output from the amplifier 220, an output signal of the detector 230 and a preset reference signal, and the resultant value Attenuation module 250 for attenuating the output signal of the comparator 240 and the attenuation control signal output from the comparator 240 and attenuating the output intermediate frequency output from the third amplifier 111 according to the attenuation control signal 250 It is composed of

The operation of the first signal loss compensator 200 configured as described above will be described in detail with reference to FIG. 2.

First, the coupler 210, which is a directional coupler, couples the local signal output from the second amplifier 106.

In this coupled local signal, the DC component is removed from the DC blocking capacitor C1 and only the AC component is passed to the amplifier 220. The amplifier 220 amplifies the transmitted signal to a predetermined level. The amplified signal is removed from the DC component in the DC blocking capacitor C2, and only the AC component is transmitted to the detector 230.

At this time, the RF choke coil L2, the bias resistor R1, and the capacitor C3 and C4 block power supply noise.

Next, as illustrated in FIG. 2, the detector 230 uses a rectifier circuit composed of a coil L2, a diode D1, and a capacitor C5 to output a signal output from the amplifier 220 to a DC component. The signal is converted into.

The converted signal is input to the inverting terminal (-) of the comparator 240, and the comparator 240 is the reference voltage Vref set by the resistor R3 input to the non-inverting terminal (+) and the inversion. Compare the detected voltage input to the terminal (-).

When the detection voltage, that is, the local signal coupled by the coupler 210 is greater than the reference voltage, the signal is determined to be a normal local level, and attenuation control signal is generated in the attenuation module 250.

When the attenuation module 250 receives the attenuation control signal from the comparator 240, the attenuation module 250 transmits a transmission intermediate frequency input to the NO terminals in the two RF switches 251 and 252. R4, R5, and R6 attenuate the level of the transmission intermediate frequency to the set gain level.

On the other hand, if the detected voltage is less than the reference voltage is a signal loss of the mixer occurs, the comparator 240 does not generate attenuation control signal.

Then, the two RF switches 251 and 252 in the attenuation module 250 turn on the NC terminals, respectively, and the transmission intermediate frequency output from the RF switch 251 is directly connected to the rear end through the RF switch 252 without attenuation. Be sure to This compensates for signal loss.

Meanwhile, the first band filter 112 filters the transmission intermediate frequency output through the attenuation module 250 in the first signal loss compensator 200 to the set band. The tracking is performed through the 4 pad part 113 and then transferred to the second mixer 118.

In this case, the local signal CH_LO output from the second voltage controlled oscillator 114 is low-pass filtered by the fourth low pass filter 115, amplified to a predetermined level by the fourth amplifier 116, and then the second signal loss compensator ( It is transmitted to the fifth pad portion 117 via the coupler 310 in the 300. The fifth pad unit 117 tracks the local signal to be transmitted, and the local signal thus tracked is transmitted to the second mixer 118.

The second mixer 118 outputs a high frequency (RF) by mixing two signals transmitted as described above, that is, a transmission intermediate frequency and a local signal, and the transmitted high frequency is the sixth pad part 119. Tracking is performed, the low pass filtering is performed by the fifth low pass filter 120, and then amplified to a predetermined level by the fifth amplifier 121, and then transmitted to the attenuation module 350 in the second signal loss compensator 300. .

The second signal loss compensator 300 detects the level of the local signal output from the second voltage controlled oscillator 114 while the transmission RF signal is processed through such a path, and detects the level of the detected local signal. Accordingly, the signal loss of the second mixer 118 is compensated for.

In more detail, the second signal loss compensator 300 is output from the fourth amplifier 116 as shown in FIG. 2, similarly to the first signal loss compensator 200. A coupler 310 for coupling a local signal, an amplifier 320 for amplifying a combined signal output from the coupler 310 to a predetermined level, and a detector 330 for detecting a signal output from the amplifier 320. And a comparator 340 for comparing the output signal of the detector 330 with a preset reference signal and generating attenuation control signal as a result, and the fifth according to the attenuation control signal output from the comparator 340. It consists of attenuation module 350 to attenuate or directly output the transmission high frequency output from the amplifier 121.

The operation of the second signal loss compensator 300 configured as described above will be described in detail with reference to FIG. 2.

First, the coupler 310, which is a directional coupler, couples a local signal output from the fourth amplifier 116.

The coupled local signal is removed from the DC component in the DC blocking capacitor C1, and only the AC component is passed to the amplifier 320. The amplifier 320 amplifies the transmitted signal to a predetermined level. The amplified signal is removed from the DC component in the DC blocking capacitor C2, and only the AC component is transmitted to the detector 330.

At this time, the RF choke coil L2, the bias resistor R1, and the capacitor C3 and C4 block power supply noise.

Next, the detector 330 converts the signal output from the amplifier 320 into a DC component signal using a rectifier circuit composed of a coil L2, a diode D1, and a capacitor C5.

The converted signal is input to the inverting terminal (-) of the comparator 340, and the comparator 340 is inverted with the reference voltage Vref set by the resistor R3 input to the non-inverting terminal (+). Compare the detected voltage input to the terminal (-).

When the detection voltage, that is, the local signal coupled by the coupler 310 is greater than the reference voltage, the signal is determined to be a normal local level, and attenuation control signal is generated in the attenuation module 350.

When the attenuation control signal is transmitted from the comparator 340, the attenuation module 350 transmits a transmission high frequency input to the NO terminals in the two RF switches 351 and 352. , R5 and R6 attenuate the level of the transmission high frequency to the set gain level.

On the other hand, if the detection voltage is less than the reference voltage is a signal loss of the mixer occurs, the comparator 340 does not generate attenuation control signal.

Then, the two RF switches 351 and 352 in the attenuation module 350 turn on the NC terminals, respectively, so that the transmission high frequency output from the RF switch 351 is directly connected to the rear end through the RF switch 352 without attenuation. do. This compensates for signal loss.

According to the present invention described above "the mixer signal loss compensation device of the base station in the communication system", the conversion loss occurs at any moment due to the characteristics of the mixer, when applying the compensation circuit according to the present invention when such conversion loss occurs There is an advantage to compensate for the loss.

In addition, when the transmitter is used in front of the power amplifier, the total power loss can be reduced to some extent to compensate for the deterioration of performance over a long period, thereby improving the performance of the entire IS-2000 base station system.

Claims (8)

A first low pass filter / amplifier for low-pass filtering the input transmission intermediate frequency and amplifying to a predetermined level, and a second low pass filter for low-pass filtering and amplifying the output signal of the voltage controlled oscillator generating a local signal for transmission intermediate frequency to a predetermined level. / Amplifier, a mixer for mixing output signals of the first amplifier and the second amplifier and outputting a transmission IF frequency, and a third low pass for outputting the output signal of the mixer to a transmission IF frequency by low-pass filtering and a predetermined level. An in-base station IF transmitter of a communication system comprising a filter / amplifier and a band pass filter for band-filtering a transmission IF frequency output from the third amplifier, Coupling a local signal transmitted to the mixer through the second amplifier, detecting a level of the combined local signal, and then adjusting the attenuation level of the transmission IF signal output from the third amplifier according to the detection level; Mixer signal loss compensation apparatus of the base station in the communication system comprising a signal loss compensation unit for transmitting to the band pass filter. The signal loss compensator of claim 1, A coupler for coupling a local signal output from the second amplifier, an amplifier for amplifying a combined signal output from the coupler to a predetermined level, a detector for detecting a signal output from the amplifier, and an output signal of the detector; A comparator for comparing a preset reference signal and generating an attenuation control signal as a result, and an attenuation module for attenuating or outputting the transmission intermediate frequency output from the third amplifier according to the attenuation control signal output from the comparator. Mixer signal loss compensation apparatus of the base station in the communication system, characterized in that configured. The method of claim 2, wherein the detector, Converting the signal output from the amplifier into a DC component signal using a rectifier circuit composed of a coil connected in series with the output terminal of the amplifier, a half-wave rectifier diode connected in series with the coil, and a capacitor connected in series with the output terminal of the diode. Mixer signal loss compensation device of the base station in the communication system characterized in that. The method of claim 2, wherein the attenuation module, A first RF switch configured to set a path of a transmission IF frequency according to an attenuation control signal output from the comparator, and an NO terminal of the first RF switch and the second RF switch, respectively, and output from the first RF switch Mixer signal loss compensation apparatus of the base station in the communication system, characterized in that the transmission attenuator attenuated to the set gain level π-type attenuator (R4, R5, R6). A voltage controlled oscillator for generating a local signal for a transmission RF signal, a first low pass filter / amplifier for low pass filtering and amplifying an output signal of the voltage controlled oscillator, a local signal output from the first amplifier and a transmission IF frequency input A mixer for generating a transmission RF signal, a second low pass filter / amplifier for low pass filtering and amplifying the output signal of the mixer to a predetermined level and outputting the RF signal as a transmission RF signal, and band filtering the transmission RF signal output from the second amplifier. An RF transmitter in a base station of a communication system composed of a band pass filter output by RF, Coupling a local signal transmitted to the mixer through the first amplifier, detecting a level of the combined local signal, and then adjusting the attenuation level of the transmitted RF signal output from the second amplifier according to the detection level; Mixer signal loss compensation apparatus of the base station in the communication system comprising a signal loss compensation unit for transmitting to the band pass filter. The method of claim 5, wherein the signal loss compensation unit, A coupler for coupling a local signal output from the first amplifier, an amplifier for amplifying the combined signal output from the coupler to a predetermined level, a detector for detecting a signal output from the amplifier, and an output signal of the detector; A comparator for comparing a preset reference signal and generating an attenuation control signal as a result, and attenuating module for attenuating or outputting the transmission intermediate frequency output from the third amplifier according to the attenuation control signal output from the comparator. Mixer signal loss compensation apparatus of the base station in the communication system, characterized in that configured. The method of claim 6, wherein the detector, Converting the signal output from the amplifier into a DC component signal using a rectifier circuit composed of a coil connected in series with the output terminal of the amplifier, a half-wave rectifier diode connected in series with the coil, and a capacitor connected in series with the output terminal of the diode. Mixer signal loss compensation device of the base station in the communication system characterized in that. The method of claim 6, wherein the attenuation module, A first RF switch connected to the first and second RF switches for setting a path of a transmission RF signal according to an attenuation control signal output from the comparator, and a NO terminal of the first and second RF switches, respectively, and outputted from the first RF switch. Mixer signal loss compensation apparatus of the base station in a communication system, characterized in that the attenuator (R4, R5, R6) for attenuating the transmitted RF signal to a set gain level.