KR101230472B1 - Multiband digital repeater - Google Patents

Abstract

Multi-band digital repeater of the present invention, RF signal processing unit for transmitting and receiving the first band signal and the second band signal with the base station or the terminal; First and second downstream frequency downconverters for frequency downconverting the first band signal and the second band signal received from the RF signal processor; A downstream ADC for converting analog signals received from the first and second downstream frequency downconverters into digital signals; A digital transmitter for digitally transmitting an output signal of the downstream ADC to a cable and receiving a digital signal from the cable; An upstream DAC converting a digital signal received from the digital transmitter into an analog signal; And first and second upstream frequency upconverters configured to up-convert the first band signal and the second band signal received from the upstream DAC to the RF signal processor.

Description

Multiband Digital Repeater {MULTIBAND DIGITAL REPEATER}

The present invention relates to a multi-band digital repeater for effectively processing a multi-band signal in a relay device. More specifically, in developing a mobile communication relay device, the present invention relates to a structure of a relay device for processing mobile communication signals of multiple bands instead of a single mobile communication signal. It is possible to configure only one DAC each, and the present invention relates to a multi-band digital repeater that can reduce the manufacturing cost of the repeater.

1 is a schematic block diagram of a digital repeater in the case of a conventional single band. As shown in FIG. 1, in general, a relay device is located between a base station and a terminal, and relays the downlink signal (downstream) of the base station to the terminal and the upstream signal (upstream) of the terminal to the base station to solve the shadow area and coverage ( coverage). Therefore, the relay device may use one mobile communication service, but may also use one or more mobile communication services. This is called a multi-band relay.

4 illustrates a method of implementing a conventional multi-band relay. In order to process a multi-band signal, a frequency downconverter and a frequency upconverter are generally designed for each band as shown in FIG. 4. A base station signal input to a donor RF signal processor is converted into an intermediate frequency signal through a frequency down converter. The analog signal is converted into a digital signal using an ADC, and then transmitted using a transmission module. The digital signal is converted into an analog signal using a DAC, and then converted into an RF signal through a frequency upconverter. This process is a conventional general multiband digital repeater structure.

In this case, the digital transmission unit may use various digital transmission methods such as an optical transmission module or an Ethernet transmission module. As shown in FIG. 4, it can be seen that many components and modules are used to implement a multi-band relay. In most multi-band repeaters, the cost of an optical transmission module or an Ethernet transmission module is high, so they are not used for each band but integrated.

2 is a block diagram of a donor RF signal processing unit of a conventional single-band repeater. 3 is a block diagram of a remote RF signal processing unit of a conventional single band repeater. The donor RF signal processing unit and the remote RF signal processing unit each include a high power amplifier (HPA), a low noise amplifier (LNA), and a high frequency termination unit (FEU) .In the case of a donor RF signal processing unit, when a wire is connected to a base station Configurations without high frequency termination (FEU) are also possible. 5 and 6 are block diagrams of a donor RF signal processing unit and a remote RF signal processing unit in a conventional multi-band relay device. It was common to use a high power amplifier (HPA) and a low noise amplifier (LNA) corresponding to each band and one high frequency terminator (FEU). As shown in FIG. 4, in order to implement a conventional multi-band relay device, many components and modules are used, and thus the cost increases.

Accordingly, the present invention has been made to solve the above problems, in the multi-band relay device using a digital transmission method, the production of equipment by reducing the number of ADC and DAC to handle multi-band (Multi-band) It is an object of the present invention to reduce the cost.

In order to achieve the above object, according to a first embodiment of the present invention, an RF signal processing unit for transmitting and receiving a first band signal and a second band signal with a base station or a terminal; First and second downstream frequency downconverters for frequency downconverting the first band signal and the second band signal received from the RF signal processor; A downstream ADC for converting analog signals received from the first and second downstream frequency downconverters into digital signals; A digital transmitter for digitally transmitting an output signal of the downstream ADC to a cable and receiving a digital signal from the cable; An upstream DAC converting a digital signal received from the digital transmitter into an analog signal; And first and second upstream frequency upconverters for frequency upconverting the first band signal and the second band signal received from the upstream DAC and transmitting them to the RF signal processor. .

Further, in the first and second downstream frequency downconverters, the downstream frequency downconversion is performed such that the first band signal and the second band signal are simultaneously included between (n-1) / Fs and n / Fs. By setting the local oscillation frequency to be mixed, only one downstream ADC is used. Here, n is a positive integer and Fs means a sampling frequency.

The sampling frequency should be at least twice the bandwidth sum of the bandwidth of the first band signal and the bandwidth of the second band signal.

The upstream DAC is also composed of one, and the first band signal and the second band signal, which can be included simultaneously between (n-1) / Fs and n / Fs, can be converted into an analog signal.

In the frequency up and down conversion method of the multi-band digital repeater according to the first embodiment of the present invention, RF signal processing step of transmitting and receiving a first band signal and a second band signal with a base station or a terminal; First and second downstream frequency downconverting steps for frequency downconverting the first band signal and the second band signal received in the RF signal processing step; A downstream ADC step of converting the analog signals received from the first and second downstream frequency down-conversion steps into digital through one downstream ADC; A digital transmission step of digitally transmitting an output signal from the downstream ADC step to a cable and receiving a digital signal from the cable; An upstream DAC step of converting the digital signal received in the digital transmission step into an analog signal using one upstream DAC; And first and second upstream frequency upconverting steps for frequency upconverting the first band signal and the second band signal received from the upstream DAC step.

Further, in the first and second downstream frequency downconversion step, the first and second band signals are downstream frequency downconverted such that they are simultaneously included between (n-1) / Fs and n / Fs. By setting the local oscillation frequency to be mixed, only one downstream ADC is used. Here, n is a positive integer and Fs means a sampling frequency.

On the other hand, according to a second embodiment of the present invention, an RF signal processing unit for transmitting and receiving a first band signal and a second band signal with a base station or a terminal; A downstream frequency downconverter for frequency downconverting the first band signal and the second band signal received from the RF signal processor; A downstream ADC for converting an analog signal received from the downstream frequency downconversion unit into digital; A digital transmitter for digitally transmitting an output signal of the downstream ADC to a cable and receiving a digital signal from the cable; An upstream DAC converting a digital signal received from the digital transmitter into an analog signal; And an upstream frequency upconversion unit configured to up-convert the first band signal and the second band signal received from the upstream DAC to the RF signal processor.

The downstream frequency downconverter may further include a local oscillation signal having an intermediate frequency that is an intermediate point between a first center frequency that is a center frequency of the first band signal and a second center frequency that is a center frequency of the second band signal. When frequency downconverts, the frequency downconverter is input to the mixer to use only one downstream frequency downconversion unit and one downstream ADC.

In addition, the sampling frequency of the downstream ADC is such that the bandwidth of the first band signal and the bandwidth sum of the second band signal are two or more times.

In addition, the upstream frequency up-conversion section, the frequency of the local oscillation signal having an intermediate frequency that is the midpoint of the first center frequency and the center frequency of the first band signal and the second center frequency of the second band signal of the first band signal frequency When up-converting, the frequency is up-converted by inputting to a mixer to use only one of the upstream frequency up-converter and the upstream DAC.

In addition, the frequency up and down conversion method of the multi-band digital repeater according to the second embodiment of the present invention, RF signal processing step of transmitting and receiving the first band signal and the second band signal with the base station or the terminal; A downstream frequency downconversion step of frequency downconverting the first band signal and the second band signal received from the RF signal processing step; A downstream ADC step of converting the analog signal received from the downstream frequency downconversion step into digital; A digital transmission step of digitally transmitting an output signal from the downstream ADC step to a cable and receiving a digital signal from the cable; An upstream DAC step of converting the digital signal received in the digital transmission step into an analog signal; And an upstream frequency upconversion step of frequency upconverting the first band signal and the second band signal received in the upstream DAC step.

Further, in the downstream frequency downconversion step, a local oscillation signal having a middle frequency, which is an intermediate point between a first center frequency that is a center frequency of the first band signal and a second center frequency that is a center frequency of the second band signal, is generated. When frequency downconverts, it is inputted to the mixer and frequency downconverted to use only one downstream frequency downconverter used in the downstream frequency downconversion step and one downstream ADC used in the downstream ADC step.

Further, in the upstream frequency up-conversion step, the local oscillation signal having the intermediate frequency, which is the intermediate point between the first center frequency that is the center frequency of the first band signal and the second center frequency that is the center frequency of the second band signal, is frequency. When up-converting, the frequency is up-converted by inputting to a mixer to use only one upstream frequency upconversion unit used in the upstream frequency upconversion step and one upstream DAC used in the upstream DAC step.

Therefore, in the multi-band digital repeater according to the present invention, it is possible to configure only one downstream ADC and upstream DAC by using the repetition characteristics of the digital signal, thereby making it possible to reduce the manufacturing cost of the repeater.

1 is a schematic block diagram of a digital repeater in the case of a conventional single band.
2 is a block diagram of a donor RF signal processing unit of a conventional single-band repeater.
3 is a block diagram of a remote RF signal processing unit of a conventional single band repeater.
4 illustrates a method of implementing a conventional multi-band relay.
FIG. 5 is a block diagram of an RF signal processor of a conventional multi-band repeater.
6 is a block diagram of a conventional multi-band remote RF signal processor.
7 is a block diagram of a multi-band digital repeater according to a first embodiment of the present invention.
8 is a block diagram of a multi-band digital repeater according to a second embodiment of the present invention.
9 illustrates a general digital signal processing method.
10 illustrates repetition characteristics of a digital signal.
FIG. 11 is a diagram illustrating a method of processing a multi-band digital signal according to a first embodiment of the present invention by using a repetition characteristic of a digital signal.
12 is a diagram illustrating a method of processing a multi-band digital signal according to a second embodiment of the present invention by using a repetition characteristic of a digital signal.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

(Embodiment 1)

7 is a block diagram of a multi-band digital repeater according to a first embodiment of the present invention. FIG. 11 is a diagram illustrating a method of processing a multi-band digital signal according to a first embodiment of the present invention by using a repetition characteristic of a digital signal. Compared with the conventional multiband digital repeater shown in FIG. 4, the number of ADCs and DACs provided for each band is reduced by half. To do this, the intermediate (IF) frequencies of the first downstream frequency downconverter 20 and the second downstream frequency downconverter 21 may be selected as shown in FIG. 11. That is, when the first band signal (center frequency is Fif1) and the second band signal (center frequency is Fif2) are disposed within a bandwidth corresponding to half of the sampling frequency (Fs: Sampling Frequency), the downstream ADC ( 40 and the upstream DAC 50 can be configured as shown in FIG. In this case, the frequencies of the local oscillator (not shown) of the first downstream frequency downconverter 20 and the second downstream frequency downconverter 21 should be used separately. Although separate local oscillators must be used, each of the first downstream frequency downconverter 20 and the second downstream frequency downconverter 21 by using a frequency divider using one local oscillator can be used. It may also provide the frequency of a local oscillator (not shown).

Similarly, in the first downstream frequency downconverter 20 and the second downstream frequency downconverter 21, the first band signal and the second band signal are between (n-1) / Fs and n / Fs. When the downstream frequency is downconverted to be included at the same time, it is possible to use only one of the downstream ADC 40 and the upstream DAC 50.

9 illustrates a general digital signal processing method. In general, in order to convert an analog signal to a digital signal, as shown in FIG. 9, in order to process the digital signal, the sampling frequency (Fs) should be selected at least twice the bandwidth of the signal to be processed, as shown in FIG. 10. The intermediate frequency (Fif) is selected using the repeated characteristics of the digital signal. The method according to the first embodiment of the present invention selects the first band signal (center frequency is Fif1) and the second band signal (center frequency is Fif2) as shown in FIG. To make it possible. At this time, the first band signal (center frequency is Fif1) and the second band signal (center frequency is Fif2) are not overlapped with each other by using a frequency up / down converter for each band, and the first band signal and the second band signal are not overlapped with each other. Do not add up to more than Fs / 2. This allows multi-band repeaters to be configured without using ADCs and DACs on a band-by-band basis.

The cable 70 may be a UTP, an optical cable, or the like, and the donor side and the remote side on the left and right sides of the cable 70 preferably have the same structure. The donor side is the side which communicates with a base station, and the remote side is the side which communicates with a terminal.

(Second Embodiment)

8 is a block diagram of a multi-band digital repeater according to a second embodiment of the present invention. 12 is a diagram illustrating a method of processing a multi-band digital signal according to a second embodiment of the present invention by using a repetition characteristic of a digital signal. As illustrated in FIG. 8, the multi-band digital repeater according to the second embodiment also uses a frequency downconverter and a frequency upconverter one by one.

When the first band signal (center frequency is Fif1) and the second band signal (center frequency is Fif2) input to the downstream ADC 40 by using the repetition characteristics of the digital signal as shown in FIG. 12, the first embodiment In comparison with this, the multi-band relay device can be implemented in a structure in which the downstream frequency down-converter 22 and the upstream frequency up-converter 32 are also used one by one.

At this time, the intermediate frequency, which is the midpoint of the first center frequency, which is the center frequency of the first band signal, and the second center frequency, which is the center frequency of the second band signal, is inputted to the mixer and down-converted.

Referring to the first case of FIG. 12, the center frequency is converted to (Fif2-Fif1) / 2 according to mixing of the frequency up and down converters, and the second band signal (center frequency is Fif2) and the first band signal. If the center frequency is Fif1, the signals of the respective bands do not overlap, and when the bandwidths of the band signals are summed to be smaller than Fs / 2, multi-band signal processing is possible. However, it should be noted that the interval of the center frequency of each band signal in the RF band is Fif2-Fif1. As the spacing of the center frequency of each band signal in the RF band increases, the Fs must be increased, which increases the price of the digital signal processor, thereby departing from the spirit of the present invention.

So what was conceived is the second, third and fourth cases of FIG. Referring to the second case of FIG. 12, when the interval of the center frequency of each band signal of the RF band can be selected as Fs-Fif2-Fif1, the first band signal uses Fif1 as it is, and instead of Fif2, Fs-Fif2 is used. If input, the center frequency interval of each band signal in the RF band is farther away than the first case of FIG. In this way, since the center frequency of the frequency up-converter and the down-converter can be selected as shown in FIG. It does not have to divide much.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood that various modifications and changes may be made without departing from the scope of the appended claims.

10 donor RF signal processor
20 First Downstream Frequency Downconversion Section
21 second downstream frequency down-conversion section
22 Downstream Frequency Downconversion Section
30 first upstream frequency up-conversion unit
31 second upstream frequency up-conversion unit
32 Upstream Frequency Upconversion Section
40 downstream ADC
50 upstream DACs
60, 80 digital transmitter
70 cables
90 downstream DAC
100 upstream ADC
110 first downstream frequency up-converter
111 second downstream frequency up-conversion unit
112 Downstream Frequency Upconversion Section
120 first upstream frequency down converter
121 Second Upstream Frequency Downconversion Unit
122 Upstream Frequency Downconversion Section
130 Remote RF Signal Processing Unit

Claims (6)

An RF signal processor for transmitting and receiving a first band signal and a second band signal with a base station or a terminal;
First and second downstream frequency downconverters for frequency downconverting the first band signal and the second band signal received from the RF signal processor;
A downstream ADC (Analog-to-Digital Converter) for converting analog signals received from the first and second downstream frequency down-converter sections into digital;
A digital transmitter for digitally transmitting an output signal of the downstream ADC to a cable and receiving a digital signal from the cable;
An upstream digital-to-analog converter (DAC) for converting the digital signal received from the digital transmitter into an analog signal; And
And first and second upstream frequency upconverters for frequency upconverting the first band signal and the second band signal received from the upstream DAC and transmitting them to the RF signal processor.
In the first and second downstream frequency down converter,
Setting a mixed local oscillation frequency such that the first band signal and the second band signal are downconverted downstream so that they are simultaneously included between (n-1) / Fs and n / Fs in the frequency domain,
And using only one downstream ADC.
Where n is a positive integer and Fs is the sampling frequency. delete The method of claim 1,
And the sampling frequency is equal to or greater than twice the bandwidth sum of the bandwidth of the first band signal and the bandwidth of the second band signal. The method of claim 3, wherein
The upstream DAC is also made of one, characterized in that the frequency band can be converted into an analog signal, the first band signal and the second band signal that can be included simultaneously between (n-1) / Fs and n / Fs, Multiband Digital Repeater. In the frequency up and down conversion method of a multi-band digital repeater,
An RF signal processing step of transmitting and receiving a first band signal and a second band signal with a base station or a terminal;
First and second downstream frequency downconverting steps for frequency downconverting the first band signal and the second band signal received in the RF signal processing step;
A downstream ADC step of converting the analog signals received from the first and second downstream frequency down-conversion steps into digital through one downstream analog-to-digital converter (ADC);
A digital transmission step of digitally transmitting an output signal from the downstream ADC step to a cable and receiving a digital signal from the cable;
An upstream DAC step of converting the digital signal received in the digital transmission step into an analog signal using one upstream digital-to-analog converter (DAC); And
And first and second upstream frequency upconverting steps for frequency upconverting the first band signal and the second band signal received from the upstream DAC step.
In the first and second downstream frequency downconversion step,
The downstream ADC by setting a local oscillation frequency mixed so that the first band signal and the second band signal are down-converted downstream to be included simultaneously between (n-1) / Fs and n / Fs in the frequency domain; Using only one, frequency up- and down-conversion method of the multi-band digital repeater.
Where n is a positive integer and Fs is the sampling frequency.
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