KR20080053805A - An if split repeater with the compensator for rf cable loss - Google Patents

Abstract

An IF split repeater having a compensator for compensating RF cable loss is provided to compensate an RF cable loss by equalizing an attenuation slop, caused by a transmission loss difference of an IF signal and a length of an RF cable, by installing an equalizer including a serial resonator within a remote unit. An IF(Intermediate Frequency) split repeater(20) comprises a donor unit(100), plural remote units(200) and an RF(Radio Frequency) cable(150). The remote unit comprises a first RF circuit unit(210), a control unit(220), a second circuit unit(230) and a compensator(250). The compensator includes an equalizer. The equalizer comprises a serial resonator where a resistance, a capacitor and an inductor are serially connected. A varactor diode is connected to the capacitor in parallel. The compensator performs compensation by equalizing attenuation characteristics, tilted due to difference of transmission loss of an IF signal generated by a frequency within each band of the IF signal transmitted by the RF cable and a length of the RF cable, by attenuating a high level signal into a low level signal according to a frequency within each bandwidth.

Description

AN IF SPLIT REPEATER WITH THE COMPENSATOR FOR RF CABLE LOSS}

1 is a block diagram showing the configuration of an IF distributed repeater using an RF cable in RF communication;

2 is a graph showing the attenuation phenomenon due to the transmission loss of the IF signal by the RF cable in the IF band (60 ㎒) in the IF distributed repeater using the RF cable,

3 is a block diagram of an IF distributed repeater having a compensator for compensating for RF cable loss according to the present invention;

4 is a diagram of a compensation algorithm of an equalizer used in an IF distributed repeater having a compensator for compensating RF cable loss according to the present invention;

5 is a view illustrating a cable loss compensation concept of an equalizer used in an IF distributed repeater having a compensator for compensating for RF cable loss according to the present invention;

6 is a circuit diagram showing an embodiment of an equalizer used in an IF distributed repeater having a compensator for compensating for RF cable loss according to the present invention;

7A to 9B are graphs showing the results of a compensation experiment for an IF distributed repeater having a compensator for compensating RF cable loss according to the present invention;

10a to 11d are graphs showing the results of a temperature characteristic experiment for an IF dispersion repeater having a compensator for compensating for RF cable loss according to the present invention;

12 is a block diagram showing an embodiment of a remote unit having a compensator in an IF distributed repeater having a compensator for compensating for RF cable loss according to the present invention;

FIG. 13 is a circuit diagram illustrating an embodiment of a compensator used in an IF distributed repeater having a compensator for compensating for RF cable loss.

14A is a graph showing experimental results when only a cable is connected between a donor unit and a remote unit in an IF dispersion repeater.

14B is a graph showing a compensation test result for an embodiment of a remote unit having a compensator in an IF distributed repeater having a compensator for compensating for RF cable loss according to the present invention.

*** Explanation of symbols for the main parts of the drawing ***

10: base station 11: terminal

20: IF dispersion repeater 21, 100: donor unit

22, 150: RF cable 23, 200: remote unit

210: RF circuit 220: control unit

250: compensator 251, 252: amplifier

253, 254: DC blocking capacitor 255: equalizer

The present invention relates to an IF distributed repeater using an RF cable, and more particularly, between a base station and a terminal for RF communication, and a donor unit (RF) communicating with the base station and the donor unit connected to the donor unit with an RF cable. In the IF distributed repeater consisting of a plurality of remote units (RF) in communication with the RF signal, the IF signal to compensate for the slope of the attenuation of the IF signal generated according to the frequency of the length of the RF cable and the band of each IF signal RF cable by installing a compensator comprising an equalizer for attenuating and smoothing a high level signal to a low level signal in the IF band of the IF band and an amplifying unit for amplifying the transmission loss caused by the RF cable of the IF signal. A compensator for compensating the RF cable loss for compensating the loss of the IF signal by The present invention relates to an IF distributed repeater.

In general, a representative mobile communication service system of bidirectional communication is composed of a base station transceiver system, a base station controller, a mobile switching center, and a mobile station. The base station and the mobile station communicate in a constant frequency band, and each base station has a constant call radius. Therefore, by arranging a plurality of base stations appropriately so that the call radius of each base station overlaps each other, the area where the call is possible can be expanded.

However, even if the entire city is covered by the arrangement of such a plurality of base stations, a call shadow area is created in the island area, the underground space of a large building, and the inside of a high-rise building, where the call is not possible. Due to the occurrence of the call shadow area, the mobile phone user may not receive smooth call service in the call shadow area, and in order to solve such a problem, a repeater is installed in the shadow area.

The repeater performs the function of amplifying the weak signal supplied from the base station to the terminal and amplifying the signal transmitted from the terminal and transmitting the signal to the base station, and such a repeater has a forward path and a reverse path. path).

Among these repeaters, the IF (Intermediate Frequency) distributed repeater receives an RF band frequency such as 800 MHz or 2 의 of the base station, downlinks the signal to an intermediate frequency (IF) of 60 to 250 MHz, processes the signal, and transmits it back to the terminal. Conversely, a reverse path for transmitting is formed, and a donor unit for receiving a signal from a base station or transmitting a signal to a base station and a remote unit for transmitting and receiving a signal to a terminal are connected to the RF cable, which is a wired cable. Configure by connecting.

The intermediate frequency (IF) of the IF distributed repeater is divided into 3G RX (60 MHz), 2G RX (110 MHz), 2G TX (185 MHz) and 3G TX (250 MHz).

1 is a block diagram showing the configuration of an IF distributed repeater using an RF cable in RF communication.

As shown, in the RF communication, the IF distributed repeater 20 includes a donor unit 21 for transmitting and receiving signals from the base station 10 and a remote unit 23 for transmitting and receiving signals to and from the terminal 11 and these donor units. Use a wired cable (22, hereinafter referred to as RF cable) that connects the remote unit.

In this case, the IF distributed repeater 20 may be connected to a plurality of remote units 23 to one donor unit 21, and is connected by an RF cable 22 to transmit an IF signal.

By the way, the RF cable 22 used between the donor unit 21 and the remote unit 23 according to the length, or each IF signal (60 MHz, 110 MHz, 185 MHz, 250 MHz) and each bandwidth Attenuation occurs due to differences in signal transmission losses of different magnitudes depending on the frequency within the antenna. That is, the loss of signal transmission increases with the length of the RF cable, and also due to the difference in the magnitude of the loss (ie, the slope within the bandwidth) between the bandwidths of each band of the IF. Attenuation occurs.

FIG. 2 is a graph showing the attenuation phenomenon of the difference in losses in the IF signal band (60 MHz) when the RF cable of 300 m in the 60 MHz band in the IF distributed repeater using the RF cable.

As shown in Fig. 2, the signal transmission loss by the RF cable used in the IF distributed repeater is about 14 ~ as shown by REF = -14 표시된 on the graph or the average value (mean = -14.941 ㏈) on the left. A signal occurring in proportion to the frequency within one band (i.e., within the same frequency band) having a center frequency of 60 MHz and a bandwidth of 20 MHz (that is, a band of 50 MHz to 70 MHz) while generating about 15 kHz. Since the difference in the transmission loss of about 2 발생 occurs, there is a problem in that a power difference between frequency allocation (FA) occurs and the quality of the transmission signal is deteriorated.

The present invention is to solve the above problems, the main object of the present invention, by installing an equalizer composed of a series resonator in the remote unit of the IF distributed repeater, RF cable connecting the donor unit and the remote unit of the IF distributed repeater The present invention provides an IF distributed repeater having a compensator for compensating for RF cable loss by smoothing attenuation slope due to a difference in propagation loss of an IF signal generated according to a frequency and a frequency within a band of each IF signal.

In addition, the present invention provides a compensator including an equalizer and an amplifier in the remote unit of the IF dispersion repeater, thereby smoothing the attenuation slope of the IF signal generated by the RF cable connecting the donor unit and the remote unit of the IF dispersion repeater. It is an object of the present invention to provide an IF distributed repeater having a compensator for compensating for RF cable loss, which amplifies and compensates for transmission loss.

In addition, an object of the present invention is to provide an equalizer or compensator having no characteristic change with respect to the temperature change by experimenting with the characteristic change with respect to the temperature change.

In order to achieve the above object, the first aspect of the IF distributed repeater having a compensator for compensating RF cable loss according to the present invention is that the length and angle of the RF cable connecting the donor unit and the remote unit of the IF distributed repeater. The high level signal is attenuated and compensated by a low level signal in the band of the IF signal due to a difference in the propagation loss of the IF signal generated according to the frequency in the band of the IF signal to be smoothed.

In addition, a second aspect of the IF distributed repeater having a compensator for compensating RF cable loss according to the present invention is a transfer loss of an IF signal generated by an RF cable connecting a donor unit and a remote unit of an IF distributed repeater. to amplify the loss.

As a preferable means for this, the IF distributed repeater having a compensator for compensating RF cable loss according to the present invention, a donor unit for RF communication with the base station between the base station and the terminal for RF communication, the terminal and the RF In the IF distributed repeater for relaying the RF communication consisting of a plurality of remote units for communication and the RF cable connecting the donor unit and the remote unit, the remote unit is the IF signal transmitted from the donor unit to the RF cable It comprises a compensator to compensate for the transmission loss by.

In the present invention, the compensator is an equalizer composed of a series resonator which is controlled by a controller connected in parallel to the IF path and electrically connected, and attenuates a high level signal to a low level signal in the IF band and smoothes it. It is characterized by the configuration.

The equalizer may be a series resonator configured to connect a varactor diode in parallel with a capacitor.

In the present invention, the compensator is characterized in that the voltage applied to the varactor diode according to the control signal output from the control unit. At this time, the control signal is characterized in that the analog voltage signal input through the DA converter.

According to another embodiment of the present invention, a donor unit for performing RF communication with the base station between a base station and a terminal for RF communication, a plurality of remote units for RF communication with the terminal, and the donor unit and a remote unit In the IF distributed repeater consisting of an RF cable for connecting the RF communication, each remote unit is connected to the RF cable, receives an IF signal from the donor unit and separates each IF signal and outputs to each IF path A first RF circuit unit; A compensator for paralleling each IF path and compensating for the loss of an IF signal transmitted from the donor unit by an RF cable; A second RF circuit unit connected to the compensator to signal-process the compensated IF signal into an RF signal and transmit the signal; And a control unit electrically connected to the first RF circuit unit, the second RF circuit unit, and the compensator to measure a loss magnitude of the IF signal and to output a control signal according to the measured data to adjust the compensator. do.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and function and the preferred embodiment of the IF dispersion repeater having a compensator for compensating the RF cable loss according to the present invention.

3 is a block diagram of an IF distributed repeater having a compensator for compensating for RF cable loss according to the present invention.

As shown, IF distributed repeater 20 having a compensator for compensating for RF cable loss according to the present invention is a donor unit 100 for transmitting and receiving a signal from a base station, a plurality of remote units for transmitting and receiving signals to a plurality of terminals 200, an RF cable 150 connecting the donor unit 100 and the remote unit 200, wherein the remote unit 200 includes a first RF circuit unit 210, a control unit 220, and a second unit. It includes a circuit unit 230 and a compensator 250.

At this time, the RF cable 150 may connect a plurality of remote units 200 to one donor unit 100, using a 5C-HFBT cable.

The compensator 250 includes an equalizer 255 (not shown) configured as a series resonator connected to an IF path (that is, between P1 and P2) in the remote unit 200, and is electrically connected to the controller. The control signal output from 220 is controlled.

The compensator 250 is the length of the RF cable 150, such as 5C-HFBT used in the IF distributed repeater 20 and each band (60 MHz, 110 MHz, 185 MHz) of the IF signal transmitted by the RF cable , 250 MHz), which compensates for the slanted attenuation characteristics due to the difference in the propagation loss of IF signals generated by frequency within the respective bandwidths. do. In this case, the bandwidth of each IF is preferably set to 20 MHz.

In addition, the control unit 220 controls the general signal processing in the first RF circuit unit 210 and the second RF circuit unit 230 in the remote unit 200 and at the same time compensating for the RF cable loss according to the present invention In the IF distributed repeater 20 having a control signal for compensating the IF signal attenuation characteristics in the compensator 250 outputs. In this case, the controller 220 uses a DA converter or a variable resistor in a digital circuit inside the controller 220 to output a control signal to the equalizer 255 included in the compensator 250. desirable. In addition, the control signal preferably uses an analog voltage signal.

4 is a diagram illustrating a compensation algorithm of an equalizer used in an IF distributed repeater having a compensator for compensating for RF cable loss according to the present invention.

As shown, Figure 4 shows a compensation algorithm for the cable loss (Cable loss) for each band of the IF used in the IF distributed repeater, since the magnitude of the loss due to the RF cable increases in proportion to the frequency increase The slope will appear as in.

In addition, as the length (50m, 100m, 200m, 300m) of the RF cable connecting the donor unit 100 and the remote unit 200 becomes longer, the slope of the loss caused by the RF cable of FIG. 4 becomes larger.

That is, when there is a frequency separation between the FWD band (TX signal) transmitted from the base station to the terminal and the RVS band (RX signal) transmitted from the terminal to the base station, there is a difference in loss due to the RF cable.

In this case, the remote unit 200 must be aware of the cable loss difference between the FWD band and the RVS band, and for this purpose, a method of measuring cable loss using a pilot signal for each service band is used.

That is, the donor unit 100 transmits eight continuous wave signals (CW signals) having different frequencies and constant outputs to the plurality of remote units 200. At this time, the remote unit 200 receives the CW signal, measures the strength of each signal, and calculates the cable loss between each band based on this data, and at the same time, the loss within the band of each signal by the RF cable 150. The difference can be measured.

On the other hand, Figure 5 is a view showing the cable loss compensation concept of the equalizer used in the IF distributed repeater having a compensator for compensating the RF cable loss in accordance with the present invention.

As shown, the cable loss in which the attenuation slope occurs due to the loss difference according to the frequency in the band of each IF signal by the RF cable 150 used in the IF distributed repeater 20, such a cable loss In order to compensate for this, the loss of the signal is compensated by using an equalizer that attenuates a high level signal of a low frequency into a low level signal and conversely amplifies a high level low level signal to a high level in a bandwidth. In practical circuit configurations, equalizers are used to attenuate high level signals at low frequencies into low level signals within a bandwidth.

Therefore, as shown in FIG. 4, the remote unit 200 measures the cable loss size by using each CW signal transmitted from the donor unit 100 as a pilot signal, and the measured data is stored in each remote. The unit 200 is collected for each unit, and each remote unit 200 is compensated using the equalizer 255 of FIG. 6 described below by the control signal of the controller 220.

6 is a circuit diagram showing an embodiment of an equalizer used in an IF distributed repeater having a compensator for compensating for RF cable loss according to the present invention.

As shown, the equalizer 255 used in the IF dispersion repeater 20 having a compensator for compensating for RF cable loss according to the present invention includes a resistor R ₁ , a capacitor C ₁ , and an inductor L ₁ . Consists of a series resonator connected in series, it is configured by connecting the varactor diode (D ₁ ) in parallel to the capacitor (C ₁ ). At this time, the equalizer 255 is configured by connecting in parallel to the IF path (P1 ~ P2) in the remote unit 200 connected by the donor unit 100 and the RF cable 150.

The equalizer 255 composed of the series resonator compensates for the difference in signal level by generating a resonance mode to attenuate a high level signal into a low level signal according to a frequency in each band. That is, the degree of loss according to each frequency band and the length of the cable can be adjusted by the resonance frequency (ω ₀ ) and the selectivity (Q).

In general, the resonant frequency (ω ₀ ) can be determined by adjusting the capacitance value (C) and inductance value (L) through calculation by a formula, and the Q value is the capacitance value (C) and the resistance value (R). Can be determined by adjustment.

That is, it is based on the relationship of Formula (1).

Accordingly, the equalizer 255 composed of the series resonator adjusts the voltage applied to the varacter diode D ₁ connected in parallel to the capacitor C ₁ with respect to the loss due to the cable length, and thus the capacitance value C. By adjusting the capacitance value (C ₁ ), the resonance frequency (ω ₀ ) and the Q value are determined and compensated.

At this time, the varactor diode (D ₁ ) used in the series resonator configured as an example is M4A2.com MA4ST2500-11410T, the characteristic values are shown in the following table.

Characteristic value of varactor diode V _R (V) C _t (pF) 0.1 86.48 0.3 76.34 0.5 67.36 1.0 46.09 1.5 22.83 2.0 10.05 2.5 7.112 3.0 5.918 3.5 5.275 4.0 4.895 4.5 4.591 5.0 4.557

As shown in Table 1, the capacitance value C _t is inversely proportional to the magnitude of the voltage V _R across the varactor diode.

Accordingly, in the equalizer 110 configured with the series resonator, the resonance frequency ω ₀ and the Q value are adjusted by adjusting the magnitude of the voltage V _R at both ends of the capacitor C ₁ connected in parallel with the varactor diode D ₁ . Will be adjusted.

7A to 9B are graphs showing the results of a compensation experiment for an IF distributed repeater having a compensator for compensating for RF cable loss according to the present invention.

The circuit conditions within each IF band are tested as follows.

Compensation test condition of each device constituting equalizer according to each IF signal R ₁ (Ohm) C ₁ (pF) L ₁ (nH) 3G RX (60 MHz) 100 One 270 2G RX (110 MHz) 0 One 270 2G TX (185 MHz) 0 One 82 3G TX (250 MHz) 0 One 47 (CI B 1608)

In addition, a 5C-HFBT cable having a characteristic impedance of 75Ω is used to test the characteristics of the equalizer 255 in the band of each IF signal according to the cable length.

IF dispersing repeater 20 when only the cable 150 is connected to the band of each IF signal and IF equalizer 255 are connected, but IF dispersing repeater when the control signal voltage is turned off to 0V ( 20), and the equalizer 255 is connected and measured in the case of the ON state of inputting a control signal voltage.

Therefore, FIGS. 7A to 7B show a case in which only the cable 22 is connected, and a graph in which the RF cable length is 300 m and the IF signals are 3G RX (60 MHz) and 3G TX (250 MHz), and FIG. 8A. 8B is a result of connecting the equalizer 255 but turning off the control signal voltage to 0 V. When the RF cable length is 300 m and the IF signals are 3G RX (60 MHz) and 3G TX (250 MHz). 9A to 9B show the result of the ON state in which the equalizer 255 is connected and the control signal voltage is input. The RF cable length is 300m and the IF signal is 3G RX (60 MHz) and 3G. The result graph in the case of TX (250 MHz).

As shown in Figure 7a to 9b, the description of each graph for the results of the experiment under the above conditions are as follows. That is, the bandwidth of each IF is 20 ㎒, the center frequency (CENTER) is specified on the bottom left of each graph, and the middle thick line represents the reference value (REF) indicating the level of the IF signal. The transfer loss value by.

In addition, the bottommost text (pp) among the texts on the right side of each graph shows the difference in the magnitude of the loss caused by the RF cable according to the size of the frequency in each IF band. ) In case 1 and mark 2 are divided into low frequency and high frequency for the bandwidth of 20 MHz of each IF signal, the difference between the maximum value and the minimum value of the signal is shown therebetween.

In the result graph, when 50m cable is connected, large ripple generated in each band is caused by impedance mismatch between the cable and the instrument.

Therefore, as a result of experiment under the above conditions, the loss magnitude according to the frequency in each IF band (60 MHz, 110 MHz, 185 MHz, 250 MHz) for the length (50m, 100m, 200m, 300m) of 5C-HFBT cable Is shown in Table 3 below.

Result of one embodiment of compensation experiment for IF dispersion repeater   3G RX (60 MHz)  Cable length (m) Maximum loss size difference Only cable Equalizer OFF Equalizer ON 50 0.74 0.64 0.64 (0.1 V) 100 0.87 0.46 0.41 (0.6 V) 200 1.27 0.86 0.40 (1.4 V) 300 1.96 1.50 0.40 (1.7 V)  2G RX (110 MHz) 50 0.65 0.61 0.43 (1.7 V) 100 0.75 0.74 0.33 (1.8 V) 200 1.13 1.13 0.34 (2.1 V) 300 1.64 1.61 0.53 (2.2 V)  2G TX (185 MHz) 50 0.39 0.40 0.21 (1.5 V) 100 0.39 0.54 0.16 (1.7 V) 200 0.74 0.98 0.14 (1.9 V) 300 1.23 1.45 0.35 (2.1 V)  3G TX (250 MHz) 50 0.49 0.27 0.27 (1.0 V) 100 0.51 0.29 0.11 (1.7 V) 200 0.88 0.64 0.18 (1.8 V) 300 1.29 1.04 0.24 (2.0 V)

In Table 3, the equalizer OFF indicates a result of setting the voltage controlling the varactor diode D ₁ to 0V while the equalizer 255 composed of the series resonator is connected in parallel to the IF path in the remote unit 200.

In addition, the equalizer ON is a result of applying the control voltage to the varactor diode D ₁ , and the numerical values in parentheses after each value represent the control voltage for determining the resonance frequency ω ₀ and the Q value in each condition.

When only the cable is connected to each IF band of Table 3, the loss component of the cable, that is, the slope of the attenuation of the signal generated by the RF cable 150 used in the IF distributed repeater 20 is proportional to the length of the RF cable. In this case, a smoothed value is shown for the length of the RF cable by applying a control voltage signal from the controller 220 to the equalizer 255 connected in parallel to the IF path in the remote unit 200.

On the other hand, Figures 10a to 11d is a graph showing the results of the temperature characteristics test for the IF dispersion repeater with a compensator to compensate the RF cable loss according to the present invention.

10A to 10D are graphs showing the results of temperature characteristics when the length of the RF cable is 300m and the IF signal is 3G TX band (250 MHz), and FIGS. 11A to 11D are 50m length of the RF cable and the IF signal is Results graph for temperature characteristics in the 3G RX band (60 MHz).

The temperature characteristic experiment was performed in the state where the equalizer 255 is installed in the remote unit 200 of the IF dispersion repeater having a compensator for compensating the RF cable loss according to the present invention, and the low temperature experiment uses a spray freeze. , High temperature experiments use a high temperature hot air fan. In addition, the temperature in each case measured the surface temperature using a surface temperature measuring instrument, and the results for each measured temperature are as follows.

Temperature characteristics when connecting 300m cable of 3G TX band (250 ㎒) Condition Maximum loss size difference Equalizer OFF 1.18  Equalizer ON (2.0 V) Room temperature (24.3 ℃) 0.35 Low temperature (-4 ℃) 0.43 High temperature (50 ℃) 0.42

Temperature characteristics when connecting 50m cable of 3G RX band (60 ㎒) Condition Maximum loss size difference Equalizer OFF 0.62  Equalizer ON (2.0 V) Room temperature (24.3 ℃) 0.61 Low temperature (-4 ℃) 0.61 High temperature (50 ℃) 0.59

As shown in Table 5, when the RF cable is 50m long and the IF signal is 3G RX band (60MHz), the effect of the equalizer is relatively high because of the large ripple component due to the impedance mismatch between the 50Ω system of the 3G RX band and the 5C cable. In this case, the characteristic change of the equalizer with respect to the temperature change is very small, about 0.02 ㏈, so that a separate temperature compensation circuit is not required.

In addition, in Table 4, when the length of the RF cable is 300m and the IF signal is 3G TX band (60 ㎒), the difference in the maximum loss size is reduced by the equalizer, but the smoothing effect is large, but the characteristic change of the equalizer with respect to temperature change Is about 0.08 미, so no separate temperature compensation circuit is required.

12 is a block diagram showing an embodiment of a remote unit having a compensator in an IF distributed repeater having a compensator for compensating for RF cable loss according to the present invention.

As shown in FIG. 12, the IF distributed repeater 20 including a compensator for compensating for RF cable loss according to the present invention includes a donor unit 100 for transmitting and receiving a signal from a base station, and a plurality of terminals for transmitting and receiving signals. Two remote units 200 and an RF cable 150 connecting the donor unit 100 and the remote unit 200, wherein the remote unit 200 includes a first RF circuit unit 210 and a controller 220. ), A second circuit unit 230 and a compensator 250.

The compensator 250 is connected between P1 and P2 of the IF path in the remote unit 200, but is transmitted to the remote unit 200 from the donor unit 100 which is transmitted and lost by the RF cable 150. An equalizer 255 composed of a series resonator in which capacitors and varactor diodes are connected in parallel so as to attenuate high level signals to low level signals in each IF band of the IF signal, and to be connected in series with P1 of the IF path. The donor comprises a first amplifier 251 installed in front of the equalizer 255 and a second amplifier 252 connected in series with P2 of the IF path and installed at the rear end of the equalizer 255. IF signal transmitted from the unit 100 to the remote unit 200 is configured to include amplification unit (251, 252) to compensate for the transmission loss generated by the RF cable 150.

In addition, it is preferable to include a DC blocking capacitor (253, 254) for blocking the DC voltage between the amplifier 251, 252 and the equalizer 255.

The equalizer 255 is a length of the RF cable 150, such as 5C-HFBT used in the IF distributed repeater 20, and each band (60 MHz, 110 MHz, 185 MHz) of the IF signal transmitted by the RF cable. , 250 MHz) according to the frequency within the bandwidth by setting the compensation slope by adjusting the resonant frequency with the voltage control signal of the control unit 220 due to the difference in the transmission loss of the IF signal generated according to the frequency It attenuates high level signals to low level signals to smooth and compensate. In this case, the bandwidth of each IF is preferably set to 20 MHz.

In addition, the control unit 220 controls the general signal processing in the first RF circuit unit 210 and the second RF circuit unit 230 in the remote unit 200 and at the same time compensating for the RF cable loss according to the present invention In the IF dispersion repeater 20 having a control signal for compensating the IF signal attenuation characteristics in the compensator 250 outputs. In this case, the controller 220 uses a DA converter in a digital circuit inside the controller 220 to output a control signal for controlling the varactor diode of the equalizer 255 included in the compensator 250. Or a variable resistor is preferable. In addition, the control signal preferably uses an analog voltage signal.

FIG. 13 is a circuit diagram illustrating an embodiment of a compensator used in an IF distributed repeater having a compensator for compensating for RF cable loss.

As shown in the circuit diagram of FIG. 13, the compensator 250 used in the IF distributed repeater 20 having a compensator for compensating for RF cable loss according to the present invention includes P1 of the IF path in the remote unit 200 and Parallel connection between P2 but the high level signal in each IF band of the IF signal transmitted to the remote unit 200 from the donor unit 100, which is transmitted and lost by the RF cable 150 as a low level signal An equalizer 255 consisting of an RLC series resonator in which capacitors and varactor diodes are connected in parallel to attenuate and smoothed, and a first RF amplifier connected in series with P1 of the IF path and installed in front of the equalizer 255. A remote unit 200 in the donor unit 100 is configured by a second amplifying unit 252 which is connected in series to the amplifying unit 251 and P2 of the IF path and constituted by an RF amplifier installed at the rear end of the equalizer 255. ) The IF signal to be transmitted is configured to include an amplifier section (251 252) to compensate for the transmission loss caused by the RF cable 150.

In addition, in order to block the DC signal and amplify only the IF signal, it is preferable to include DC blocking capacitors 253 and 254, respectively, before and after the RF amplifier.

14A is a graph showing experimental results when only a cable is connected between a donor unit and a remote unit in an IF distributed repeater, and FIG. 14B is provided with a compensator in an IF distributed repeater having a compensator for compensating RF cable loss according to the present invention. A graph showing the results of a compensation experiment for an embodiment of a remote unit.

Table 6 below shows the compensation test conditions for the compensator 250.

Compensation test condition for compensator R ₁ 0 Ω C ₁ 1 ㎊ L ₁ 56 nH Circuit applied voltage (V _cc ) 5 V Voltage applied to varactor diodes (V _R ) 2.6 V Cable type / length 5C-HFBT / 300m IF band 3G TX (250 MHz)

As shown in FIG. 14A, when only the RF cable 150 is connected between the donor unit 100 and the remote unit 200 in the IF dispersion repeater 20, the frequency is generated according to the frequency within the IF bandwidth by the RF cable 150. The difference in propagation loss is about 1.69 ,, and the IF signal loss is about 30 듯이 as the average value between marks 1 and 2 on the left side of the graph (mean: -29.657 ㏈). It can be seen that.

14B is a compensation for an embodiment of a remote unit 200 having a compensator 250 in an IF distributed repeater 20 having a compensator for compensating for RF cable loss according to the present invention under the conditions shown in Table 6. A graph showing an experimental result is shown. The equalizer 255 in the compensator 250 smoothes the difference of the transmission loss magnitude generated according to the frequency in the IF bandwidth to 0.44 kHz. In addition, since the mean value in the graph of FIG. 14B is 2.16 mW, this indicates that the transfer loss of the compensator 250 compensated for about 32 mW by the amplifiers 251 and 252.

Therefore, the IF distributed repeater having a compensator for compensating the RF cable loss according to the present invention is according to the length of the RF cable and the IF frequency when the donor unit and the remote unit in the IF distributed repeater are connected using only the RF cable. It completely compensates for the propagation loss of the generated IF signal.

However, the scope of the present invention is not limited to the above-described embodiments and the accompanying drawings, and those skilled in the art may have various substitutions, modifications, and changes within the scope without departing from the technical spirit of the present invention. Therefore, the scope of the present invention should be interpreted according to the matters described in the claims to be described later.

As described above, the IF distributed repeater having a compensator for compensating RF cable loss according to the present invention connects an equalizer composed of a series resonator in which a capacitor and varactor diode are coupled in parallel to an IF path in a remote unit, and the equalizer By connecting the control unit for inputting the control signal to the, there is an effect to smooth the slope of the attenuation due to the magnitude of the transmission loss of the IF signal increases with increasing frequency in the IF band equal to the length of the RF cable. At this time, the equalizer does not need a separate temperature compensation circuit, even if the temperature variation of -4 ~ +50 ℃ deviation of the characteristics of the equalizer is about 0.1 ㏈.

In addition, the IF dispersion repeater having a compensator for compensating the RF cable loss according to the present invention, by connecting in parallel the equalizer consisting of a series resonator configured by coupling a capacitor and varactor diode in parallel to the IF path in the remote unit, Located in the IF paths at the front and rear ends of the equalizer, respectively, an amplification unit for amplifying the transmission loss generated by the RF cable from the IF signal transmitted from the donor unit is connected in series, and a control unit for inputting a control signal to the equalizer is connected. By smoothing the difference in the magnitude of the transmission loss of the IF signal, which increases as the frequency increases in the same IF band as the length of the RF cable, the effect of compensating for the transmission loss of the IF signal generated by the RF cable is achieved. have.

Claims (12)

RF communication between the base station and the terminal for RF communication with the base station and the base station, a plurality of remote units for RF communication with the terminal, and an RF cable connecting the donor unit and the remote unit In IF distributed repeater, And the remote unit comprises a compensator for compensating for the loss of the IF signal transmitted from the donor unit by the RF cable. The method of claim 1, The compensator is controlled by a controller connected in parallel and electrically connected to the IF path in the remote unit, characterized in that the equalizer composed of a series resonator to attenuate the high level signal to a low level signal in the IF band to smooth. IF distributed repeater with compensator to compensate RF cable loss. The method of claim 2, And the equalizer is a series resonator configured to connect the varactor diodes in parallel with a capacitor. The method of claim 3, wherein And the compensator adjusts a voltage applied to the varactor diode according to a control signal output from the controller. The method of claim 4, wherein And the control signal is an analog voltage signal input through a DA converter. The method of claim 4, wherein And the control unit comprises a DA converter or a variable resistor in order to adjust the voltage of the varactor diode. RF communication comprising a donor unit for RF communication with the base station between the base station and the terminal for RF communication, a plurality of remote units for RF communication with the terminal, and an RF cable connecting the donor unit and the remote unit In IF distributed repeater to relay Each remote unit includes: a first RF circuit unit connected to the RF cable and receiving an IF signal from a donor unit, separating the IF signal into respective IF signals, and outputting each IF path; A compensator for paralleling each IF path and compensating for the loss of an IF signal transmitted from the donor unit by an RF cable; A second RF circuit unit connected to the compensator to signal-process the compensated IF signal into an RF signal and transmit the signal; And And a controller electrically connected to the first RF circuit unit, the second RF circuit unit, and a compensator to measure a loss magnitude of the IF signal and to output a control signal according to the measured data to adjust the compensator. IF distributed repeater with compensator to compensate RF cable loss. The method of claim 7, wherein The compensator includes: four equalizers each including a series resonator in which a capacitor and varactor diodes are connected in parallel to attenuate a high level signal into a low level signal in each IF band of an IF signal transmitted from the donor unit; And Compensator for compensating the RF cable loss, characterized in that consisting of; amplifying section for amplifying the transfer loss of the IF signal transmitted from the donor unit in series connected to the IF path of the front and rear stages of each equalizer; One IF distributed repeater. The method according to claim 7 or 8, And the compensator adjusts the voltage across the varactor diode according to a control signal output from the control unit. The method of claim 7, wherein And the control signal is an analog voltage signal input through a DA converter. The method of claim 7, wherein And the control unit comprises a DA converter or a variable resistor in order to adjust the voltage of the varactor diode. The method of claim 7, wherein And a compensator for compensating the RF cable loss, wherein the equalizer and the amplifying unit include a capacitor blocking a DC voltage.

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