KR20060038688A - Frequency conversion device for base transceiver system - Google Patents

Abstract

A frequency converter for a base station capable of easily expanding the number of available channels is provided.

According to the present invention, in implementing uplink and downlink frequency conversion apparatuses used in a base transceiver station RF circuit, an intermediate frequency is set differently for each channel, so that SAW filters having a difference in the center frequency by channel intervals are added by the number of available channels. In addition, the components used for amplifying, combining, or separating signals can be shared, thereby implementing a frequency conversion device having a simple structure and low implementation cost.

Base Station, Frequency Conversion, SAW Filter

Description

Frequency conversion device for base station {Frequency Conversion Device for Base Transceiver System}

1 is a view for explaining the configuration of a general base station;

2 is a detailed configuration diagram of the RF module shown in FIG.

3 is a detailed configuration diagram of an RF module according to channel increase;

4 is a configuration diagram of a general uplink frequency converter;

5 is a configuration diagram of a base station frequency converter according to an embodiment of the present invention;

6A and 6B are diagrams for explaining a concept of frequency separation in a SAW filter;

7 is a configuration diagram of a base station frequency converter according to another embodiment of the present invention.

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

1: interface unit 2: modulation and demodulation unit

3: transceiver 4: radio module

5 transmitting antenna 6 receiving antenna

10: RF transmitter 20: RF receiver

110: first amplifier 120-1, 120-2, 160-1, 160-n: first mixer

130-1, 130-2, 170-1, 170-n: SAW Filter                 

140: second mixer 150: second amplifier

The present invention relates to a base station apparatus in a mobile communication system, and more particularly, to a base station frequency conversion apparatus capable of easily increasing the number of available channels.

In general, in a mobile communication system, one base station operates several channels, and in order to expand a channel in the base station, a large amount of cost is required because an RF module of the base station needs to be added.

1 is a view for explaining the configuration of a general base station.

A base station is a network termination device that is directly connected to a mobile communication terminal by performing baseband signal processing, wired / wireless conversion, and transmission / reception of a wireless signal. An interface unit (1) providing an interface with a base station controller and a signal from a base station controller A demodulation unit (2) for modulating and demodulating a signal received from a mobile communication terminal, a transceiver (3) for transmitting the demodulated signal, and a baseband signal from a base station controller to convert a baseband signal into a high frequency band signal for transmission antenna (5) It transmits to the air through the, and includes a RF module (4) for converting the signal of the high frequency band received by the receiving antenna (6) from the mobile communication terminal to the baseband signal.

FIG. 2 is a detailed configuration diagram of the RF module shown in FIG. 1 and illustrates a case where only one channel is used.

The RF module 4 may be divided into a transmitter 10 and a receiver 20, and the transmitter 10 is an upconverter (upper frequency converter 12) and a high frequency band for converting a baseband coral into a signal of a high frequency band. An amplifier 14 for amplifying the converted signal and a transmission filter 16 for removing noise from the amplified signal, and the receiving end 20 includes a reception filter 26 for removing noise of the received signal; An amplifier 24 for amplifying the filtered signal and a down converter (downlink frequency converter) 22 for converting the amplified signal to a baseband signal.

If a channel is extended for a base station using only one channel, the base station is implemented as shown in FIG. 3. 3 is a detailed configuration diagram of the RF module according to the channel increase.

As shown, the up converters 12-1 to 12-n of the transmitter 10, the amplifiers 14-1 to 14-n, and the down converters 22-1 to 22-n of the receiver 20 are As the number of channels is required, there is a problem that the configuration of the base station RF module is complicated and expensive at the time of channel expansion.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and there is a technical problem to provide a base station frequency conversion apparatus capable of minimizing the channel expansion cost of the base station and simplifying the structure of the base station transceiver.

The present invention for achieving the above technical problem is a first amplifier for receiving and amplifying a plurality of baseband signals to be transmitted to each channel; A plurality of first mixers configured to output different intermediate frequency signals by applying different intermediate frequencies to each of the baseband signals input from the first amplifier; A plurality of SAW filters having different center frequencies, each of which receives an intermediate frequency signal output from the plurality of first mixers and performs channel separation; A second mixer converting signals output from each of the plurality of SAW filters into high frequency signals; And a second amplifier amplifying the output signal of the second mixer and outputting the amplified signal to the air through an antenna.

In addition, the present invention comprises a first amplifier for receiving and amplifying a plurality of high-frequency band signals transmitted to each channel from the mobile communication terminal; A plurality of first mixers configured to output different intermediate frequency signals by applying different intermediate frequencies to each of the plurality of high frequency band signals input from the first amplifier; A plurality of SAW filters having different center frequencies, each of which receives an intermediate frequency signal output from the plurality of first mixers and performs channel separation; A second mixer converting a signal output from each of the plurality of SAW filters into a baseband signal; And a second amplifier for amplifying and outputting the output signal of the second mixer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a configuration diagram of a general uplink frequency converter, and shows a case where two channels are used.

The baseband signal LF for transmission through each channel is transmitted from the base station, input to the first amplifiers 110-1 and 110-2, and amplified, respectively, and the first mixers 120-1 and 120-. Is converted into an intermediate frequency signal MF. Thereafter, the intermediate frequency signals are input to the SAW filters 130-1 and 130-2, respectively, to separate the channels, and then the second mixers 140-1 and 140-2 and the second amplifiers 1501-150 are performed. The signal is output as the high frequency signals HF1 and HF2 through -2).

As such, the baseband signal LF input to the two uplink frequency converters (upconverter) and the intermediate frequency signal MF output from the first mixers 120-1 and 120-2 are the same, respectively. It can be seen that only the high frequency signal radiated into the air is different. The baseband signal LF is the same because the structure and frequency of the baseband circuit of the RF module stage are the same, and the intermediate frequency signal MF uses the same SAW filter having a constant center frequency. SAW filter prevents crosstalk and noise by passing only the frequency of a specific band and blocking the frequency of other band. It is used to generate accurate channel separation.

Therefore, if the SAW filter having the center frequency difference by the channel interval is used, it is possible to simplify the configuration of the uplink and downlink frequency conversion apparatus used for the base station RF module using a plurality of channels.

5 is a configuration diagram of a base station frequency converter according to an embodiment of the present invention, and shows an example of an uplink frequency converter.

As shown, the uplink frequency converter for a base station according to the present invention is input from the first amplifier 110, the first amplifier 110 for receiving and amplifying a plurality of baseband signals to be transmitted to each channel A plurality of first mixers 160-1 to 160-n and a plurality of first mixers 160 that apply different intermediate frequencies to each of the plurality of baseband signals and output them as different intermediate frequency signals MF1 to MFn. A plurality of SAW filters 170-1 to 170-n and a plurality of SAW filters having different center frequencies for receiving channel signals MF1 to MFn output from -1 to 160-n, respectively, and performing channel separation. A second mixer 140 for converting the signals output from the respective signals 170-1 to 170-n to a high frequency signal and a second for amplifying the output signals of the second mixer and outputting the plurality of high frequency signals HF1 to HFn. It consists of an amplifier 150.

Here, each SAW filter 170-1 to 170-n has a center frequency different from each other, and the center frequency has a difference by a channel interval used by the base station. A description with reference to FIG. 6 is as follows.

6A and 6B are diagrams for describing a concept of frequency separation in a SAW filter.

First, FIG. 6A is a diagram illustrating filtering characteristics of a SAW filter currently used in a frequency converter for a base station. Each frequency converter, which is added together whenever a channel is expanded, has a SAW filter having the same center frequency (MF). Since the signals have to be processed by different frequency converters, the more complicated the channel, the more complicated the structure of the frequency converter is.

6B is a diagram illustrating filtering characteristics of a SAW filter applied to the present invention. As shown, for example, in a base station frequency conversion apparatus using two channels, each SAW filter has different center frequencies MF1 and MF2, and the center frequencies are set to have a difference by channel interval. .                     

7 is a configuration diagram of a base station frequency converter according to the present invention, and shows an example of a downlink frequency converter.

As shown, the downlink frequency conversion apparatus for a base station according to the present invention includes a first amplifier 210, a first amplification unit for amplifying a plurality of high frequency signals (HF1 ~ HFn) received through each channel from the mobile communication terminal A plurality of first mixers 220-1 to 220-n and a plurality of first mixers for converting each of a plurality of high frequency signals input from the unit 210 into signals MF1 to MFn having different intermediate frequencies. A plurality of SAW filters 230-1 to 230-n having different center frequencies for receiving channel inputs MF1 to MFn outputted from 220-1 to 220-n, respectively, and performing channel separation. By amplifying the output signals of the second mixer 240 and the second mixer 240 for separating the I and Q components from the signals output from the SAW filters 230-1 to 230-n, respectively, The second amplifier 250 outputs the baseband signals LF1 to LFn.

Here, each SAW filter 230-1 to 230-n has a center frequency different from each other, and the center frequency has a difference by a channel interval used by the base station.

In the frequency conversion apparatus for the base station of the present invention described with reference to FIGS. 5 and 7, the center frequency has a difference by channel interval, and by using the same number of SAW filters as the number of channels, the intermediate frequency is used differently for each channel, By using the first amplifier, the second mixer, and the second amplifier in common, the configuration of the frequency converter can be simplified, and the design cost can be reduced.

On the other hand, in recent years, high-speed portable Internet service (WiBro service) is preparing to be used, the base station of the WiBro system can use up to three channels, for example, depending on the frequency allocation scheme per operator. Accordingly, when the frequency converter of the present invention is applied to a WiBro base station, three channels can be supported by a simple method, thereby reducing the base station equipment price.

As such, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof. Therefore, the above-described embodiments are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

According to the present invention described above, in configuring a frequency conversion device used for the RF module of the base station, the frequency conversion device is not increased for each expansion of the channel, and different intermediate frequencies are used for each channel. Unlike SAW filters with the same frequency, the SAW filters with different center frequencies can simplify the configuration of the frequency converter and reduce the cost of implementing the frequency converter. .

Claims (4)

A first amplifier configured to receive and amplify a plurality of baseband signals to be transmitted through respective channels; A plurality of first mixers configured to output different intermediate frequency signals by applying different intermediate frequencies to each of the baseband signals input from the first amplifier; A plurality of SAW filters having different center frequencies, each of which receives an intermediate frequency signal output from the plurality of first mixers and performs channel separation; A second mixer converting signals output from each of the plurality of SAW filters into high frequency signals; And A second amplifier amplifying an output signal of the second mixer and outputting the amplified signal to the air through an antenna; Frequency conversion device for a base station comprising a. A first amplifier configured to receive and amplify a plurality of high frequency band signals transmitted from the mobile communication terminal to each channel; A plurality of first mixers configured to output different intermediate frequency signals by applying different intermediate frequencies to each of the plurality of high frequency band signals input from the first amplifier; A plurality of SAW filters having different center frequencies, each of which receives an intermediate frequency signal output from the plurality of first mixers and performs channel separation; A second mixer converting a signal output from each of the plurality of SAW filters into a baseband signal; And A second amplifier for amplifying and outputting an output signal of the second mixer; Frequency conversion device for a base station comprising a. The method according to claim 1 or 2, And the plurality of SAW filter center frequencies are set to have a difference by the channel interval. The method according to claim 1 or 2, The SAW filter is a frequency conversion device for a base station, characterized in that provided by the number of channels.

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