KR100884250B1 - Tower Mounted Amplifier with Simplified Structure and Mobile Base Station Including the Same - Google Patents

Abstract

The present invention relates to a TMA and a mobile communication base station system including the same. The TMA according to the present invention includes a transmission filter for filtering a transmission signal transmitted from a mobile communication base station; A reception filter for filtering a received signal received from the base station antenna; A low noise amplifier for amplifying the received signal filtered by the receive filter; And a down converter converting the received signal amplified by the low noise amplifier into a signal of an intermediate frequency band. According to the present invention, the receiver of the TMA and the mobile communication base station can be implemented in a smaller size, there is an advantage that the cost can be reduced.

TMA, Downconverter, Duplexer

Description

Tower Mounted Amplifier with Simplified Structure and Mobile Base Station Including the Same}

1 is a block diagram showing the configuration of a conventional TMA and a telecommunications base station receiver system.

Figure 2 is a block diagram showing the configuration of a TMA according to an embodiment of the present invention.

3 is a block diagram illustrating a configuration of a mobile communication base station system receiver according to an exemplary embodiment of the present invention when the TMA of FIG. 2 is applied.

The present invention relates to a tower mounted amplifier (hereinafter referred to as "TMA"), and more particularly, to a TMA mounted in a mobile communication base station system to amplify a transmission signal and a reception signal.

The mobile base station amplifies a signal to be transmitted by a high power amplifier located in the base station when transmitting a signal, and then transmits a transmission signal to an antenna installed in the tower through a feed cable, and the antenna installed in the tower radiates the transmission signal . In addition, the mobile communication base station system amplifies a weak reception signal by receiving a signal from the antenna installed in the tower and transmitting the signal to a low noise amplifier in the base station through a feed cable.

In such a mobile communication base station system, the base station system and the antenna are generally installed at a considerable distance, and there is a problem that the signal is attenuated while the transmission signal and the reception signal are transmitted through the feed cable. When the base station system and the antenna reaches several tens of meters, more than 3dB of the input signal may be attenuated, which may cause a decrease in reception sensitivity due to a relative increase in reception.

In order to solve this problem, when the antenna and the base station are installed far away, the use of a TMA having a transmission / reception filter and an amplifier and installed adjacent to the antenna is being changed.

1 is a block diagram showing the configuration of a conventional TMA and a telecommunications base station receiver system.

Referring to FIG. 1, a conventional TMA includes a first transmission filter 100, a first reception filter 102, a low noise amplifier (LNA), and a second reception filter 106. Meanwhile, the mobile communication base station receiver system includes a second transmission filter 108, a third reception filter 110, a power amplifier (PA) 112, an upconverter 114, a downconverter 120, and an A / D. Converter 122 and D / A converter 116.

In the conventional TMA and mobile communication base station receiver system, the transmission signal modulated at the front end of the mobile communication receiver when the signal is transmitted is converted into an analog signal by the D / A converter 116, the up-converter 114 of the intermediate frequency band Convert the received signal into a signal of high frequency band.

The transmission signal converted by the upconverter 114 is amplified by the power amplifier 112 and filtered by a second transmission filter 108 that functions as a duplexer.

The transmission signal filtered by the second transmission filter is input to the TMA, and the first transmission filter 100 and the second reception filter 106 of the TMA serve as a duplexer for the signal transmitted from the mobile communication base station system receiver. . In the mobile communication system, when the transmission frequency and the reception frequency are different, duplexing is possible by FDD (Frequency Division Multiplexing), and the transmission signal from the mobile communication base station system receiving unit is blocked by the second receiving filter 106. And the first transmission filter 100 passes. Therefore, the transmission signal from the mobile communication base station receiver is transmitted to the antenna only through the signal transmission line through the transmission filter 100 and radiated to the outside.

On the other hand, when receiving a signal, the first receive filter 102 and the transmit filter 100 function as a duplexer for the signal transmitted from the antenna. The received signal transmitted from the antenna is blocked by the first transmit filter and the first receive filter 102 set to pass the band of the received signal passes.

The received signal filtered by the first receive filter 102 is amplified by the low noise amplifier 104, and the amplified received signal is filtered by the second receive filter 106. The filtered signal is transmitted to the mobile communication base station system receiver through a feed cable, and the second transmit filter 108 and the third receive filter 110 function as duplexers for signals transmitted from the TMA. The received signal from the TMA passes through a third receive filter set to pass the frequency band of the received signal and is amplified by the low noise amplifier 118.

The amplified signal is converted into a signal of the intermediate frequency band of several tens of megabytes by the down converter 120, and is converted into a digital signal by the A / D converter 122 and processed.

The conventional TMA and the mobile communication base station system receiver as described above require a plurality of transmit filters 100, 108 and receive filters 102, 106, 110 for multiplexing signals. Also, a number of low noise amplifiers 104 and 118 are needed for noise cancellation of the signal passing through the filter.

As a transmission filter and a reception filter installed in a TMA and a mobile communication base station system receiver, a cavity filter including a plurality of resonators is mainly used. Cavity filter is a filter that performs filtering by using the resonator and the signal resonance through the cavity, and is an expensive device having a relatively large size and a complicated structure.

The receiver of the conventional TMA and mobile communication base station system should be provided with a large number of such expensive equipment, and the low noise amplifier used to amplify the high frequency signal should be installed every time the signal passes through the filter. When there was an inefficient problem.

In order to solve the conventional problems as described above, the present invention is to propose a TMA and a receiver system of a mobile communication base station that can be implemented in a smaller size.

Another object of the present invention is to propose a TMA and a mobile communication base station receiver system which can be implemented at a lower cost.

Another object of the present invention is to propose a TMA and a receiver system of a mobile communication base station capable of duplexing transmission and reception signals by a simplified structure.

Still other objects of the present invention will be readily understood through the following description of the embodiments.

In order to achieve the above object, according to an aspect of the present invention, in the Tower Mounted Amplifier (TMA) installed adjacent to the base station antenna to process the RF signal, the transmission transmitted from the mobile communication base station A transmission filter for filtering the signal; A reception filter for filtering a received signal received from the base station antenna; A low noise amplifier for amplifying the received signal filtered by the receive filter; And a down converter for converting the received signal amplified by the low noise amplifier into a signal of an intermediate frequency band.

The TMA may further include a low pass filter that filters the received signal converted into the intermediate frequency band by the down converter and blocks the transmission signal from the mobile communication base station.

The low pass filter may comprise an LC lump circuit.

According to another aspect of the invention, the TMA unit is installed adjacent to the base station antenna and amplifies the transmission signal, and downconverts the received signal received from the base station antenna to the intermediate frequency band; There is provided a mobile communication base station system including a transmission signal processor for providing a transmission signal to the TMA unit and a signal receiver for filtering a received signal downconverted by the TMA unit.

The TMA unit includes: a transmission filter for filtering a transmission signal transmitted from the signal processing front end unit; A reception filter for filtering a received signal received from the base station antenna; A low noise amplifier for amplifying the received signal filtered by the receive filter; A down converter converting the received signal amplified by the low noise amplifier into a signal of an intermediate frequency band; And a low pass filter for filtering the received signal converted into the intermediate frequency band by the down converter and blocking the transmission signal from the mobile communication base station.

 The signal receiver may include: a low pass filter for filtering a received signal transmitted from the TMA; And an A / D converter for converting the received signal filtered by the low pass filter into a digital signal.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the TMA and mobile communication base station receiver system of the simplified structure according to the present invention.

2 is a block diagram showing the configuration of a TMA according to an embodiment of the present invention.

Referring to FIG. 2, a TMA according to a preferred embodiment of the present invention includes a transmit filter 200, a receive filter 202, a low noise amplifier 204, a downconverter 206, and a low pass filter 208. : LPF).

The transmit filter 200 and the receive filter 202 installed at the front end of the TMA function as a duplexer for the signal transmitted from the antenna. In a CDMA mobile communication system, a transmission frequency and a reception frequency are set differently, and the transmission filter 200 and the reception filter 202 perform duplexing by frequency division. The duplexer is a device for dividing a transmission signal and a reception signal when the transmitting end and the receiving end share the same antenna, and the transmission filter 200 and the reception filter 202 transmit a transmission signal and a reception signal through a predetermined path. Function to make it delivered.

The transmission filter 200 is a band pass filter set to pass a signal in a transmission frequency band, and the reception filter 202 is a band pass filter set to pass a signal in a reception frequency band.

The transmit filter 200 and the receive filter 202 may be cavity filters having a plurality of resonators. Such a cavity filter performs resonance in a TE or TM mode according to a structure, and has a cavity and a cavity corresponding to the order of the filter. The present invention is not limited to the use of the cavity filter as the transmission filter 200 and the reception filter 202, and it is possible to use various types of filters for filtering high frequency signals used in mobile communication. It will be self-evident.

When the received signal is transmitted from the antenna, the transmission filter 200 serves to block the received signal from entering the transmission path. Since the transmission filter 200 is set to pass only the frequency band of the transmission signal, the reception signal transmitted from the antenna passes only the reception filter 202.

The signal filtered by the receive filter 202 is input to the low noise amplifier 204. The received signal received by the antenna is transmitted over a long path, reduced to a weak signal level, and affected by noise. In addition, the effects of noise can be further weighted through filtering.

Thus, the received signal filtered by the receive filter 202 is amplified with the noise minimized by the low noise amplifier 204. A low noise amplifier is an amplifier designed by setting an operating point and a matching point so that the noise figure is low, and is typically an amplifier designed to have a noise figure of 1.5 to 2.5.

The low noise amplifier 204 receives a DC power supply and amplifies the received signal. In this case, the DC power may be provided from the base station, and according to an embodiment of the present invention, the DC signal may be provided through a feed cable connecting the base station and the TMA. In this case, a bias (not shown) for separating the RF signal and the DC signal may be additionally provided.

According to another embodiment of the present invention, a low noise amplifier 204 may be driven by converting a transmission output into a DC voltage without having a separate bias, which is disclosed in Korean Patent No. 593204, registered by the present applicant. It is disclosed in detail.

It will be apparent to those skilled in the art that a DC power source can be applied to the low noise amplifier in various ways known in addition to the manner described above.

The received signal amplified by the low noise amplifier is input to the down-converter 206, and the down-converter 206 functions to convert a high frequency mobile communication system received signal into a tens of mega bands of an intermediate frequency band signal. The down converter 206 generates a signal of a frequency band corresponding to a difference between the frequency f1 of the received signal and the frequency f2 provided by the local oscillator (not shown), thereby converting the received signal of the high frequency band into a signal of the intermediate frequency band. Downconverting, the frequency f2 of the local oscillator is suitably set such that the received signal is downconverted to a signal in the intermediate frequency band.

As the downconverter 206, both a downconverter using a passive element such as a diode and a downconverter using an active element such as a transistor may be used. When using an active element, a separate DC power supply may be applied as in the case of the low noise amplifier 204.

In the conventional TMA, high frequency band filtering is performed on a signal amplified by a low noise amplifier. However, according to a preferred embodiment of the present invention, a TMA stage is applied to an intermediate frequency band for a signal amplified by a low noise amplifier. Perform downconversion.

In the related art, a band pass filter for filtering an amplified signal after amplifying a received signal by the low noise amplifier 204 has been provided, but when down converting is performed in the TMA, it is not necessary to provide a relatively expensive and large band pass filter. . Therefore, there is an advantage that can simplify the size of the TMA and reduce the cost.

The received signal converted into the signal of the intermediate frequency band by the down converter 206 is filtered by a low pass filter (208). The low pass filter 208 functions to pass only signals in the intermediate frequency band, which is the low frequency band.

According to a preferred embodiment of the present invention, the low pass filter 208 may be an LC Lumped Circuit implemented with an inductor and a capacitor element. The low pass filter implemented by the LC lump circuit is smaller than the cavity type filter and can be implemented at low cost.

The transmission filter 200 filters the transmission signal transmitted from the mobile communication base station receiver system. The transmission signal filtered by the transmission filter 200 is radiated through the antenna.

When the transmission signal is introduced into the TMA, the band pass filter and the transmission filter 200 for the received signal conventionally operated as a duplexer, but according to a preferred embodiment of the present invention, the low pass filter 208 and the transmission filter ( 200) acts as a duplexer.

3, the mobile communication base station system receiving unit according to an embodiment of the present invention, the D / A converter 300, the up-converter 302, the power amplifier 304, the power filter 306, the low pass Pass filter 308 and A / D converter 310.

In FIG. 3, the D / A converter 300 functions to convert a digitally modulated transmission signal into an analog signal.

The signal converted by the D / A converter 300 is input to the upconverter 302. The upconverter upconverts the modulated intermediate frequency band transmission signal into a high frequency band signal.

The up-converter 302 generates a signal of a frequency band corresponding to the sum of the frequency f1 of the transmission signal and the frequency f2 provided by the local oscillator (not shown), thereby converting the transmission signal of the intermediate frequency band into a signal of the high frequency band. Up-converting, the frequency f2 of the local oscillator is suitably set such that the transmission signal is upconverted to a signal of a high frequency band.

As the upconverter 206, both an upconverter using a passive element such as a diode and an upconverter using an active element such as a transistor may be used.

The transmission signal converted by the upconverter 206 is amplified by the power amplifier 304. According to an embodiment of the present invention, a feed forward type power amplifier capable of handling multiple carriers or one carrier having a wide bandwidth may be used. The feedforward method is formed by two feedback loops, which combine the input of the amplifier with no distortion and the output of the distorted amplified signal, the main signal disappears by the feedback loop, and the remaining signal has only the distorted signal. . This signal is amplified by the error amplifier and combined with the final output of the main amplifier in a 180-degree inversion, thereby eliminating distorted sidebands and amplifying only the main signal.

The transmission signal amplified by the power amplifier 304 is filtered by the transmission filter 306 and output to the TMA stage.

On the other hand, the transmit filter 306 and the low pass filter 308 operate as a duplexer for the received signal transmitted from the TMA.

The conventional mobile communication base station receiver is used as a duplexer by installing a band pass filter for a high frequency signal in each of a transmission path and a reception path. However, according to a preferred embodiment of the present invention, since the received signal is down-converted in the TMA to receive a signal of an intermediate frequency band, a high frequency band pass filter such as a cavity filter does not need to be installed in the receiver.

Therefore, it is sufficient to have a low pass filter 308 for passing a signal in an intermediate frequency band in the reception path, and does not include a large size and expensive band pass filter as in the prior art.

The received signal of the intermediate frequency band passing through the low pass filter is converted into a digital signal by the A / D converter 310.

Although not shown in FIG. 3, an amplifier for amplifying the received signal passing through the low pass filter may be further provided, wherein the amplifier is a low noise amplifier for amplifying while removing noise of a high frequency signal. An amplifier may be used.

Therefore, according to a preferred embodiment of the present invention, since down-conversion is performed in the TMA, the mobile communication base station receiver system does not need to include a high-frequency bandpass filter, which is a conventionally expensive equipment, and is a simple device such as an LC lump circuit. You can use a low pass filter implemented by.

In addition, even if a low noise amplifier for low noise amplification of the signal received by the mobile communication base station system receiver is provided, the received signal may be smoothly provided inside the base station.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit and scope of the present invention. Additions should be considered to be within the scope of the following claims.

As described above, according to the preferred embodiment of the present invention, the receiver of the TMA and the mobile communication base station can be implemented in a smaller size, and the cost can be reduced.

In addition, according to a preferred embodiment of the present invention, there is an advantage that the duplexing of the transmission signal and the reception signal by the simplified structure.

Claims (7)

In a tower mounted amplifier (TMA) installed adjacent to a base station antenna and processing an RF signal, A transmission filter for filtering a transmission signal transmitted from the mobile communication base station; A reception filter for filtering a received signal received from the base station antenna; A low noise amplifier for amplifying the received signal filtered by the receive filter; A down converter converting the received signal amplified by the low noise amplifier into a signal of an intermediate frequency band; And And a low pass filter for filtering the received signal converted into the intermediate frequency band by the down converter and blocking the transmission signal from the mobile communication base station, wherein the low pass filter comprises an LC lump circuit. TMA. delete delete A TMA unit installed adjacent to the base station antenna and amplifying a transmission signal and downconverting the received signal received from the base station antenna into an intermediate frequency band; A transmission signal processing unit for providing a transmission signal to the TMA unit and a signal receiving unit for filtering the received signal down-converted by the TMA unit, The TMA unit, A transmission filter for filtering a transmission signal transmitted from the signal processing front end; A reception filter for filtering a reception signal received from the base station antenna; A low noise amplifier for amplifying the received signal filtered by the receive filter, A down converter for converting the received signal amplified by the low noise amplifier into a signal of an intermediate frequency band, and And a low pass filter for filtering the received signal converted into the intermediate frequency band by the down converter and blocking the transmission signal from the mobile communication base station. The low pass filter comprises a LC lump circuit. delete delete The method of claim 4, wherein The signal receiver, A low pass filter for filtering the received signal transmitted from the TMA; And And an A / D converter for converting the received signal filtered by the low pass filter into a digital signal.

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