KR100677534B1 - Relay device for mobile communication system - Google Patents

Abstract

The present invention relates to a relay apparatus for a mobile communication system such as a cellular phone. In the relay apparatus according to the present invention, the input signal from the terminal is amplified and transmitted to the base station adaptively depending on the strength of the input signal applied from a communication terminal such as a cellular phone or irrespective of the presence or absence of the input signal. To this end, in the relay apparatus according to the present invention, the line coupler 7 is installed on the transmission line for the first amplifier 5 to amplify the frequency signal received from the terminal, and the frequency is input to the first amplifier 5. Will branch the signal. The gain adjusting signal generating means 8 generates a gain adjusting signal proportional to the level of the frequency signal branched from the line coupler 7 and applies it to the first amplifier 5. At this time, the first amplifier 5 variably sets or determines whether or not to transmit the gain level of the frequency signal transmitted to the base station based on the gain adjustment signal.

Repeater, Gain Control, Line Coupler

Description

Repeater for Mobile Communication System {Repeater for Mobile communcations system}

1 is a block diagram showing the configuration of a relay device for a mobile communication system according to an embodiment of the present invention.

FIG. 2 is a characteristic curve diagram showing an example of an amplification gain characteristic of the first amplifier 5 in FIG.

3 is a configuration diagram showing an example of a specific configuration of the gain adjustment signal generator 8 in FIG.

4 is a characteristic curve diagram for explaining the operating characteristics of the log amplifier 81 in FIG.

Figure 5 is a block diagram showing a relay device for a mobile communication system according to another embodiment of the present invention.

6 is a configuration diagram showing another configuration example of the gain adjustment signal generator 8 in FIG.

        ******* Brief description of the main parts of the drawings *******

1, 2: antenna, 3, 4: duplex filter,

5, 6: amplification unit, 7: line coupler,

8: Gain adjustment signal generator.

The present invention relates to a repeater for amplifying a transmission / reception signal between a communication terminal and a base station such as a cellular phone, and more particularly, from a terminal adaptively or independently of the strength of an input signal applied from a communication terminal. A relay apparatus for a mobile communication system configured to amplify an input signal and transmit the amplified signal to a base station.

Recently, a mobile communication system that enables a user to perform voice calls and data transmission and reception while traveling is widely used. Such a mobile communication system divides a call area into cell units, and sets base stations for each cell unit so that users can perform communication through these base stations. These base stations and terminals usually perform data transmission and reception using frequency signals between several hundreds of MHz and several kilohertz, and also install and operate a plurality of relay devices in consideration of communication shadow areas such as indoors.

The relay device amplifies a signal (forward link signal) from the base station and provides it to the terminal, and amplifies a signal (reverse link signal) from the terminal and provides it to the base station so that data can be smoothly transmitted and received between the base station and the terminal. . In particular, the relay device detects a transmission loss between the base station and the relay device based on the strength of the signal received from the base station, and adjusts the amplification gain of the signal received from the terminal based on the strength of the signal transmitted from the terminal to the base station through the relay device. The signal strength is set to an appropriate level.

On the other hand, as the number of high-rise buildings and apartments has recently increased, the number of relay devices coupled to one cell, that is, one base station has exploded. However, if the number of relay devices increases in this way, the reception environment of the base station is deteriorated, and thus the reception sensitivity of the base station is reduced.

That is, in the conventional relay device, since the signal of the reverse link is amplified based on the signal strength of the forward link received from the base station, the relay device always transmits a signal toward the base station regardless of whether there is a signal of the reverse link applied from the terminal. Will be In other words, when there is no signal of the reverse link received from the terminal, a noise signal having a predetermined signal strength is continuously transmitted toward the base station. Therefore, for example, when the general white noise intensity is -128 dBm and the reverse link amplification gain of the repeater is 60 dB, in the absence of the reverse link signal, approximately -68 dBm from the relay to the base station is obtained. The noise signal is sent out. When considering only one relay, the transmission loss from the relay to the base station is approximately 70-100 dB, so the intensity of the noise signal received from the relay to the base station is up to -138 dBm. It has a negligible signal strength. However, if the number of relay devices associated with the base station increases more than a certain number, the number of the noise signals received by the base station also rapidly increases, and thus the strength of the noise signal is increased due to the overlapping of the noise signals. In addition, the increase in the strength of the noise signal greatly reduces the reception sensitivity of the base station.

The above problems occur not only in general RF relay relays but also in optical relay apparatuses, and therefore, the number of relay apparatuses associated with one base station should be limited to a certain level or less for the service provider. You will be constrained.

Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to provide a relay device for a mobile communication system which can minimize a decrease in reception sensitivity of a base station by transmission of a noise signal.

It is another object of the present invention to provide a relay device for a mobile communication system which can minimize the power loss of the relay device by minimizing the signal transmission time of the relay device.

In another aspect of the present invention, a repeater for a mobile communication system includes a service antenna for transmitting and receiving a frequency signal to and from a terminal. First amplifying means for amplifying the frequency signal received through the service antenna, transmitting means for transmitting the frequency signal amplified by the first amplifying means through a base station, and a level of the frequency signal input to the first amplifying means. And a gain adjustment signal generating means for generating a gain adjustment signal proportional to the first amplification means, amplifying the input frequency signal based on the gain adjustment signal.

The gain adjusting signal generating means includes a second amplifying means for amplifying the input frequency signal with nonlinear gain characteristics, and a bias means for outputting a driving current having a level corresponding to the output of the amplifying means. It features.

In accordance with a second aspect of the present invention for realizing the above object, a repeater for a mobile communication system includes a service antenna for transmitting and receiving frequency signals to and from a mobile communication system repeater for amplifying transmission and reception data between a base station and a terminal. First amplifying means for amplifying the frequency signal received through the service antenna, transmitting means for transmitting the frequency signal amplified by the first amplifying means through a base station, and a level of the frequency signal input to the first amplifying means. And a gain adjustment signal generating means for generating a high or low level gain adjustment signal based on the first amplification means, wherein the driving is controlled on / off based on the gain adjustment signal. .

In addition, the gain adjustment signal generating means includes an integrating means for outputting a level signal corresponding to the strength of an input frequency signal, a third amplifying means for amplifying the output of the integrating means, and an output level of the amplifying means. Comparison means for outputting a detection signal of a high or low level compared to a reference level, and switching on / off driven according to the detection output of the comparison means to output a high or low level gain adjustment signal for the first amplification means It characterized in that it comprises a means.

In addition, it characterized in that it further comprises a delay means for delaying the frequency signal input to the first amplifying means in front of the first amplifying means.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the present invention can be equally applied to a general RF relay device and an optical relay device, but the following description will describe the present invention based on the RF relay device.

1 is a block diagram showing the configuration of a relay device for a mobile communication system according to an embodiment of the present invention. In the drawing, reference numeral 1 is a service antenna for data transmission and reception with a terminal, and 2 is a donor antenna for data transmission and reception with a base station. The antennas 1 and 2 are respectively coupled with first and second duplex filters 3 and 4 for separating the received frequency signal and the transmitted frequency signal, and are transmitted and received between the duplex filters 3 and 4, respectively. The first and second amplifiers 5 and 6 for amplifying the frequency signal are coupled through the coupling capacitors C1 to C4. These antennas 1 and 2, the first and second duplex filters 3 and 4, and the first and second amplifiers 5 and 6 are substantially the same as those employed in a general repeater.

In the above basic configuration, the frequency signal received from the terminal received through the service antenna 1 is applied to the first amplifier 5 through the first duplex filter 3 and amplified, and the amplified frequency signal is the second duplex. It is sent to the base station through the filter 4 and the donor antenna 2. In addition, the frequency signal received from the base station received through the antenna (2) is applied to the second amplifier 6 through the second duplex filter (4) and amplified, and the amplified frequency signal is serviced with the first duplex filter (3). It is sent to the terminal via the antenna (1).

On the other hand, the line coupler 7 is coupled to the line between the first duplex filter 3 and the first amplifier 5. This line coupler 7 has another line (hereinafter referred to as an induction line) disposed adjacent to the transmission line between the first duplex filter 3 and the first amplifier 5. One end of the induction line is grounded through the resistor R1, and the other end is coupled to the input of the gain adjustment signal generator 8, which will be described later, through the coupling capacitor C5. The resistor R1 is for impedance matching with the gain adjustment signal generator 8. When a frequency signal input through the first duplex filter 3, that is, a frequency signal from the terminal is transmitted to the first amplifier 5 through a transmission line, a transmission line is formed on the induction line of the line coupler 7. An induction current (frequency signal) of a level corresponding to the level of the frequency signal transmitted through is flown, and this induction current is input to the gain adjustment signal generator 8.

The gain adjustment signal generator 8 generates a gain adjustment signal corresponding to the level of the signal applied from the line coupler 7 and applies it to the first amplifier 5. That is, when the received signal from the terminal is present and the level of the induced signal input through the line coupler 7 is high, a gain adjustment signal is generated to increase the amplification gain of the first amplifier 5, and the received signal from the terminal. If the level of the induced signal input through the line coupler 7 is low, the amplification gain is set low, or a gain adjustment signal for stopping the amplification operation is generated and applied to the first amplifier 5. do.

The first amplifier 5 comprises a plurality of amplifiers connected in series for proper amplification gain setting. These amplifiers consist of, for example, a model AH1 device manufactured by WJ Communications INC. Fig. 2 is a characteristic curve showing the gain characteristic of this AH1. This AH1 amplifier has an amplification gain of approximately 18 to 10 dB for an input frequency signal of approximately 70 MHz to 1.7 kHz when the bias voltage applied from the gain adjustment signal generator 8 is 2.04 to 5 V. When the voltage drops below 2.0V, the amplification gain is drastically lowered. This amplification gain characteristic is generally the same in the case of amplifiers other than the AH1 device.

The first amplifier 5 amplifies the frequency signal input from the first duplex filter 3 when the gain adjustment signal applied from the gain adjustment signal generator 8 is set to a predetermined level or more. The signal is transmitted to the base station through the second duplex filter 4 and the donor antenna 2. In addition, when the gain adjustment signal applied from the gain adjustment signal generator 8 is set to a predetermined level or less, the first amplifier 5 sets its amplification gain close to 0 dB. That is, the first amplifier 5 is substantially set to the off driving state. Therefore, in this case, the first amplifying unit 5 outputs the input signal as it is, with almost no amplification, or blocks the input signal from being output through the output terminal.

3 is a configuration diagram showing a specific configuration example of the gain adjustment signal generator 8 in FIG. In FIG. 3, the gain adjustment signal generator 8 includes a log amplifier 81 for outputting a predetermined level signal corresponding to the strength of the input frequency signal, and an amplifier for amplifying the level signal output from the log amplifier 81. And a bias circuit 83 including a resistor R2 and a transistor 831.

In the drawing, the log amplifier 81 includes, for example, a product name AD8314 log amplifier manufactured by an analog device company, which integrates an input frequency signal to generate a signal having a predetermined level corresponding to the strength of the input signal. It amplifies and outputs with nonlinear gain characteristics.

4 is a characteristic curve diagram illustrating the operation of the log amplifier 81. In general, when a frequency signal transmitted from a terminal is integrated with a corresponding signal, the integrated signal does not change linearly according to the strength of the frequency signal but has an exponential function according to the strength of the frequency signal as shown in FIG. Will have The log amplifier 81 amplifies the input signal with a gain characteristic complementary to that of the signal strength, as indicated by the dotted line in FIG. 3. Therefore, as shown in FIG. 4, the log amplifier 81 outputs an amplified signal whose output level changes linearly with the strength of the input signal.

The output from the log amplifier 81 is then amplified a predetermined level through the amplifier 82 and then applied to the bias circuit 83. In the bias circuit 83, the output of the amplifier 82 is coupled to the base of the transistor 831 through the resistor R1, and the transistor 831 outputs a gain control signal corresponding to the signal level applied to the base. As a result it is applied to the first amplifier 5.

That is, the gain adjustment signal generator 8 linearly drives the bias circuit 83 on the basis of the strength of the frequency signal input from the line coupler 7 so as to be proportional to the level of the input frequency signal. Will generate and print it.

Next, the operation of the device having the above configuration will be described.

The frequency signal received from the base station to the repeater is input to the second amplifier 6 through the donor antenna 2 and the second duplex filter 4 like the conventional repeater, and then the second amplifier 6 The frequency signal is amplified and transmitted from the base station thus amplified to the terminal through the first duplex filter 3 and the service antenna 1.

Meanwhile, the frequency signal received through the service antenna 1 including white noise is applied to the first amplifier 5 through the first duplex filter 3, and the first amplifier 5 is a gain adjustment signal. The frequency signal inputted on the basis of the gain adjustment signal applied from the generator 8 is amplified and transmitted to the base station through the second duplex filter 4 and the donor antenna 2.

First, in a state in which a frequency signal transmitted from the terminal is received through the service antenna 1, an induced signal having a predetermined intensity or more is guided through the line coupler 7 and applied to the gain adjustment signal generator 8. As described above, when a signal having a predetermined intensity or more is input to the gain adjustment signal generator 8, the gain adjustment signal generator 8 generates a gain adjustment signal of a predetermined level or more and uses the first amplifier as a bias voltage. 5) is applied. When a bias voltage of a predetermined level or more is applied to the first amplifier 5, the first amplifier 5 amplifies the frequency signal inputted through the service antenna 1 with a high amplification gain so as to obtain a donor antenna 2. Will be output to the

In addition, when there is no frequency signal received through the service antenna 1 from the terminal, the induced signal induced through the line coupler 7 and applied to the gain adjustment signal generator 8 is equal to or less than the signal strength corresponding to white noise. Will be set to. As a result, the level of the gain adjustment signal output from the gain adjustment signal generator 8 is set to a level close to the " 0 " level or " 0 " level. Therefore, in this case, the amplification gain of the first amplifier 5 is set to be close to 0 dB or is set to the off driving state, so that the signal strength output from the first amplifier 5 to the donor antenna 2 side is white noise. It will be set at a very low level below the level.

On the other hand, when there is no frequency signal received from the terminal via the service antenna 1 from the terminal suddenly receives a frequency signal from the terminal, that is, from the terminal in the state that the first amplifier 5 is set to the non-driven state When the frequency signal of is received through the service antenna 1, the corresponding received frequency signal is directly applied to the input terminal of the first amplifier 5 in which the amplification gain is set to almost 0 dB. At the same time, an induced signal corresponding to the signal strength of the received frequency signal is induced by the line coupler 7 and applied to the gain adjustment signal generator 8, which is output from the gain adjustment signal generator 8. The amplification gain of the first amplifier 5 is set to a normal state by the gain adjustment signal.

At this time, the delay time from the gain adjustment signal generator 1 to the gain adjustment signal generator 8 until a gain adjustment signal of a predetermined level or more is output is approximately 100 ns. Since the delay time from the gain of 0 dB to the normal gain is approximately 700 ns, the frequency signal from the terminal input to the first amplifier 5 is approximately 800 ns in total data of the initial section. Is not transmitted to the base station and is discarded.

In general, there are two channels used for the reverse link from the terminal to the base station, an access channel and a traffic channel. In this case, the channel signal transmitted from the terminal to the base station is prioritized, so that the delay time by the gain adjusting signal generator 8 and the first amplifier 5 may affect the access channel data. .

In general, however, in the case of the access channel, the data rate is fixed at 4.8 Kbps, and in order to transmit and receive more accurate data, the access channel data is divided into preamble data and capsule data. . In this case, the preamble data includes four preamble data having a time length of 1.25 ms, and the signal interval is set to approximately 5 ms in total. Therefore, the delay time by the gain adjustment signal generator 8 and the first amplifier 5 is less than the time equivalent to one preamble data, so that normal service is performed to the terminal by forming an abnormal reverse link. There is nothing that cannot be provided.

As described above, in this embodiment, since the amplification gain of the transmission signal to the base station is variably set regardless of the presence or absence of the frequency signal received through the service antenna 1, a noise signal of a predetermined level or more is transmitted from the relay apparatus to the base station. It can solve the problem of sending continuously.

5 is a block diagram showing a relay device for a mobile communication system according to another embodiment of the present invention. In FIG. 5, the same reference numerals are attached to substantially the same parts as FIG. 1 described above, and a detailed description thereof will be omitted.

In FIG. 5, a delay circuit 51 is provided between the line coupler 7 and the first amplifier 5 to delay the frequency signal from the terminal received through the service antenna 1 for a predetermined time. . The delay circuit 51 has a delay time by the gain adjustment signal generator 8 and the first amplifier 5, that is, a guidance signal is applied to the gain adjustment signal generator 1 and then the gain adjustment signal generator ( The first amplification by the delay time until the corresponding gain adjustment signal is outputted from 8) and the delay time until the gain of the first amplifier 5 reaches the normal gain from 0 dB. The delay time is set so as to delay the frequency signal from the terminal applied to the section 5. The delay circuit 51 delays the frequency signal applied to the first amplifier 5 through the line coupler for a predetermined time for a predetermined time, so that the gain adjustment signal generator 8 and the first amplifier ( By solving the problem that the initial section of the frequency signal transmitted from the terminal is not transmitted to the base station due to the delay time of 5), the reliability of the relay device can be improved.

6 is a configuration diagram showing another configuration example of the gain adjustment signal generator 8 in FIG. In FIG. 6, the same reference numerals are given to substantially the same parts as FIG. 3, and detailed description thereof will be omitted.

The gain adjustment signal generator 8 shown in FIG. 6 determines whether the output from the amplifier 82 is above or below a predetermined level instead of the bias circuit 83 in FIG. And a switching unit 85 having a comparator 84 for outputting and a switch that is turned on / off in accordance with the output level from the comparator 84.

In the configuration of FIG. 6, when the signal output from the amplifier 82 is above a certain level, that is, when the transmission data from the terminal is received through the service antenna 1 and the duplex filter 3 in FIG. 1, the switching unit 85 is used. Switch 851 is turned on to apply a gain adjustment signal of a predetermined level to the first amplifier 5, and switches when the signal output from the amplifier 82 is below a predetermined level, that is, there is no transmission data from the terminal. The switch 851 of the unit 85 is turned off to apply a gain adjustment signal having a "0" level to the first amplifier 5.

Therefore, when the gain adjustment signal generator 8 shown in FIG. 6 is employed in the configuration of FIG. 1, when there is data received from the terminal, the first amplifier 5 is driven with a predetermined amplification gain to the base station. In case that no signal is received from the terminal and no data is received from the terminal, the first amplifier 5 is driven with 0 dB of additional gain to stop transmitting the frequency signal to the base station.

As described above, according to the present invention, when there is no signal received from the terminal to the relay device, the level of the signal transmitted from the relay device to the base station is set low or the transmission of the signal is stopped, and the signal is received from the terminal to the relay device. If there is a signal, a normal level transmission signal is sent from the relay device.

Therefore, in the case of using a plurality of relay devices in combination with one base station, the relay device is not always set to the driving state but is selectively driven when there is a transmission signal, so that the base station is caused by the noise signal transmitted from the relay device. Can reduce the reception sensitivity.

In addition, in the above configuration, since the relay device is selectively driven according to the presence or absence of a transmission signal from the terminal, power consumption of the relay device can be reduced.

In addition, the present invention is not limited to the above-described embodiments and can be carried out in various modifications without departing from the technical gist of the present invention.

For example, in the above-described embodiment, the amplification gain of the relay apparatus for the base station is set based on the presence or absence of the received signal from the terminal. In addition, the gain of the outgoing signal for the base station based on the received signal level from the base station. It is also possible to use a gain adjusting means for adjusting the power supply.

Further, in the above-described embodiment, it is also possible to detect the output level of the bias circuit 83 or the switching unit 851 to calculate the utilization efficiency of the relay device and the like.

In addition, in the above-described embodiment, the case where the present invention is applied to the RF relay apparatus has been described as an example, but the present invention can be applied to the general optical relay apparatus in the same manner.

In the embodiment shown in Fig. 4, the gain adjustment signal is determined by integrating and linearly amplifying the level of the input frequency signal without employing the log amplifier 81, and determining whether the amplified level is above or below a predetermined level. It is also possible to generate.

That is, the present invention may be limited only by the contents described in the claims.

As described above, according to the present invention, a relay for a mobile communication system can minimize power loss of a repeater by minimizing a decrease in reception sensitivity of a base station by transmission of a noise signal and minimize signal transmission time of a repeater. The device can be implemented.

Claims (6)

In the relay device for a mobile communication system for amplifying the transmission and reception data between the base station and the terminal, A service antenna for transmitting and receiving a frequency signal to a terminal; First amplifying means for amplifying a frequency signal received through the service antenna; Transmitting means for transmitting the frequency signal amplified by the first amplifying means through a base station; And a gain adjustment signal generating means for generating a gain adjustment signal for increasing the amplification gain of the first amplifying means when the level of the input frequency signal is high in proportion to the level of the frequency signal inputted to the first amplifying means. Become, And the first amplifying means amplifies the input frequency signal based on the gain adjustment signal. The method of claim 1, The gain adjustment signal generating means includes second amplifying means for amplifying the input frequency signal with nonlinear gain characteristics; And a biasing means for outputting a driving current having a level corresponding to the output of the second amplifying means. The method of claim 1, And a delay means for delaying a frequency signal input to the first amplifying means in front of the first amplifying means. In the relay device for a mobile communication system for amplifying the transmission and reception data between the base station and the terminal, A service antenna for transmitting and receiving a frequency signal to a terminal; First amplifying means for amplifying a frequency signal received through the service antenna; Transmitting means for transmitting the frequency signal amplified by the first amplifying means through a base station; A gain adjustment signal for generating a low level gain adjustment signal when the level of the frequency signal input to the first amplifying means is higher than or equal to a predetermined level, and when the level of the frequency signal input to the first amplifying means is lower than or equal to a predetermined level; It comprises a generating means, And the first amplifying means is controlled to be off when the level of the gain adjustment signal is at a low level. The method of claim 4, wherein The gain adjustment signal generating means includes an integration means for outputting a level signal corresponding to the strength of the input frequency signal; Third amplifying means for amplifying the output of the integrating means, Comparison means for outputting a high or low level detection signal by comparing the output level of the third amplification means with a predetermined reference level; And switching means for driving on / off in accordance with the detection output of the comparing means to output a high or low level gain adjustment signal for the first amplifying means. The method of claim 4, wherein And a delay means for delaying a frequency signal input to the first amplifying means in front of the first amplifying means.

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