KR100938488B1 - Remote optical unit - Google Patents

Abstract

The present invention relates to a remote optical unit capable of increasing the efficiency of a large power amplifier, reducing heat and power consumption, and realizing optimized circuit design and miniaturization.

To this end, the present invention provides a remote optical unit including a ROU integrated module for reducing the PAPR and performing digital predistortion through the CFR in the process of outputting the signal input from the main hub unit to the duplexer.

Base station, optical repeater, repeater, main hub unit, remote optical unit.

Description

Remote optical unit

The present invention relates to a remote optical unit of an optical relay system for transmitting and receiving a signal, and more particularly, a remote optical unit that can increase efficiency of a large power amplifier, reduce heat and power consumption, and realize optimized circuit design and miniaturization. It is about.

In general, a mobile communication system divides an entire service area into a plurality of base station (BS) areas to form cells, which are small service areas, and converts these base stations to a mobile switching center (MSC). It is a system that allows the subscriber to continue the call while moving between the cells by centralized control.

Among the equipment constituting the mobile communication system, an optical repeater is installed to cover a shadow area where the sensitivity of radio waves is weak or not reached at all, and is mainly behind a high-rise building in an urban environment or the basement of a building. Installed inside subways, tunnels, and in some outlying areas.

The basic concept of the optical repeater is that the main hub unit (MHU) and the remote optical unit of the optical repeater are connected by an optical cable, and the main hub unit (MHU) converts the RF signal received from the base station into an optical signal. It transmits to the remote optical unit, and the remote optical unit restores and amplifies it back to the RF signal to provide a communication service to the user.

1 shows an example of a remote optical unit of such a conventional optical relay system, and converts an optical signal transmitted from a main hub unit (MHU) into an electrical signal to convert a clock / data signal and a reference frequency signal into an optical signal. Linearization of the digital optical converter 10, the FPGA unit 11 for separating the clock signal and the data signal in synchronization with the reference frequency signal, and serializing and outputting the data signal, and the high power amplifier (HPA) 15 Digital predistorter (DPD) 12 for predistorting and outputting the input signal for output, a DAC unit 13 for converting the input digital signal into an analog signal, and an uplink frequency converter 14 for upconverting the input signal. ), A large power amplifier 15 for amplifying the input signal with high output power, and a duplexer D for outputting a signal input from the large power amplifier 15 to the antenna so as to separate the transmission and reception signals to prevent cross talk. Is made of.

In the related art, a downlink frequency converter 16 downconverts a signal detected at an output terminal of a large power amplifier 15 and a digital low pass signal is input from the downlink frequency converter 16 for feedback of a signal for linearization. The FPGA unit 17 for filtering and the DSP unit 18 for sampling the digital low pass filtered signal, converting it into a digital signal, and outputting the digital signal to the DPD unit 12 are provided.

Also, conventionally, a low noise amplifier (LNA) 19, which is a high frequency amplifier for lowering the noise figure of a signal input through the duplexer D, and a down frequency converter 20 for converting the signal input from the low noise amplifier 19 downward. And the ADC unit 21 for converting the digital signal input from the downlink frequency converter 20 into an analog signal to perform the reverse link.

However, such a conventional remote optical unit has the advantage of increasing the efficiency of the large power amplifier 15, reducing unnecessary power consumption and somewhat reducing the appearance by employing the digital predistortion unit 12, a plurality of FPGA unit 11 (17), the DPD unit 12, which is a digital predistortion unit, and the DSP unit 18, which is a digital signal processing unit, are configured and operated separately, thereby causing problems such as an increase in the number of parts, power consumption, and cost increase. In addition, there are limitations in improving performance and miniaturization of repeater performance.

In addition, in the conventional remote optical unit, the signal input to the ADC unit 21 in the reverse link process is input to the digital optical conversion unit 10 through the FPGA unit 11, thereby increasing the circuit structure and power consumption. The problem is that the appearance is also large.

In particular, since the conventional remote optical unit uses multiple FA (Frequency Assignment), the PAPR (Peak to Average Power Ratio) of the summed signal is 1 ~ 2dB by digital combining and digitally filtering the multiple FAs in the process. The degree of increase in characteristics has been generated, which leads to an increase in power consumption and a serious problem of lowering the efficiency of the large power amplifier 15.

The present invention has been made to solve the conventional problems as described above, the object of the present invention is to reduce the PAPR of the summation signal generated by the use of the multi-FA, the remote optical unit that can increase the efficiency of the power amplifier To provide.

In addition, another object of the present invention is to provide a remote optical unit that integrates the digital predistortion unit and the DSP unit to the FPGA unit, thereby reducing the number of components, power consumption and miniaturization of the product.

An object of the present invention as described above, in the remote optical unit including a ROU integration module for reducing the PAPR and performing digital predistortion through the CFR in the process of outputting the signal input from the main hub unit to the duplexer, the ROU integration module The optical switch is configured to transmit and receive an optical signal with the main hub unit; A digital optical module configured to transmit and receive an optical signal with the optical switch; An FPGA unit for transmitting and receiving signals to and from the digital optical module and reducing PARR through CFR and performing digital predistortion and digital signal processing; A DAC unit converting the digital signal input from the FPGA unit into an analog signal and outputting the analog signal; An up frequency converter for up-converting and outputting a signal input from the DAC unit; A large power amplifier for power amplifying the signal input from the uplink frequency converter and outputting the amplified signal to a duplexer; A downlink frequency converter for down-converting and outputting the signal coupled from the output terminal of the large power amplifier; An ADC unit for converting a signal input from the downlink frequency converter into a digital signal and outputting the digital signal to the FPGA unit; A CPU unit for processing the information transmitted from the digital optical module and the FPGA unit and transmitting the information to the optical module and the FPGA unit; A low noise amplifier for low noise amplifying and outputting the signal input from the duplexer; A downlink frequency converter for down-converting and outputting the signal input from the low noise amplifier; It may be achieved through a remote optical unit comprising an ADC unit for converting the analog signal input from the downlink frequency conversion unit into a digital signal and output to the digital optical module.

According to the present invention, the FA detection unit, the FA filter unit, the CFR unit, the DPD unit, and the DSP unit are integrated and modularized through the FPGA unit, thereby reducing the number of circuit components and reducing power consumption. There is a very useful effect that can be done.

In addition, since the present invention reduces the PAPR increase through the CFR unit, it has a very useful effect of lowering the power consumption rate and reducing the number of parts while obtaining an output signal of the same level with a low capacitance structure.

Furthermore, the present invention has a useful effect of greatly reducing signal interference by improving isolation between paths because the low noise amplifier and the downlink frequency converter are modularized in the ROU integrated module.

FIG. 2 is a block diagram illustrating a connected remote optical unit ROU1 as an example of a remote optical unit according to the present invention. As shown in FIG. 2, the ROU integration module 100 and the duplexer D are largely formed.

Here, the ROU integration module 100 receives an optical signal from the main hub unit (MHU) in the case of the forward link, converts the optical signal into an RF signal, and transmits the signal to the duplexer (D), and in the case of the reverse link, transmits the signal transmitted from the duplexer (D). The optical signal is converted into an optical signal and transmitted to the main hub unit MHU.

In addition, the duplexer (D) band-filters the signal transmitted from the ROU integration module 100 in the case of the forward link and transmits the signal to the antenna, and transmits the signal transmitted from the antenna in the case of the reverse link to the ROU integration module 100. Done.

Hereinafter, the ROU integration module 100 will be described in detail.

As shown in FIG. 2, the ROU integration module 100 includes an optical switch 150, a digital optical module 200, an FPGA unit 300, a DAC unit 400, an up frequency converter 450, and a large power source. To amplifier 500, downlink frequency converter 550, ADC unit 600, CPU unit 650, duplexer (D), low noise amplifier 700, downlink frequency converter 750, ADC unit 800 Is done.

First, the optical switch 150 is transmitted and received with the optical signal to the main hub unit (MHU), the optical signal input from the main hub unit (MHU) is switched to output to the digital optical module 200, or the digital optical module The optical signal input from the 200 is switched to output to the main hub unit (MHU).

Here, the optical switch 150 is a digital optical module of the remote optical unit ROU1 when the other remote optical unit ROU2 of the termination type is connected as shown in FIG. 3, and receives the optical signal input from the main hub unit MHU. Switched to the digital optical module 201 of the remote optical unit (ROU2) different from the (200) or outputs to the main hub unit (MHU) by switching the signal input from the digital optical module (200) (201). .

In addition, the optical switch 150 switches the signal input from the digital optical module 201 and outputs the signal directly from the digital optical module 201 to the main hub unit (MHU). And outputs to the main hub unit MHU by switching the signal of the remote optical unit ROU2 input from the digital optical module 200.

As such, since the optical switch 150 switches and inputs and outputs signals of various ROU integration modules 100 and 101, the optical switch 150 may transmit optical signals more efficiently, thereby reducing the cost of the remote optical unit.

Digital optical module 200 is transmitted and received through the optical signal with the optical switch 150, in the case of the forward link outputs the optical signal input from the main hub unit (MHU) to the FPGA unit 300 and In the reverse link, the optical signal input from the ADC 800 is output to the optical switch 150.

The FPGA unit 300 transmits and receives a signal to and from the digital optical module 200. In the case of the forward link, the FPGA unit 300 detects FA information of the optical signal transmitted from the digital optical module 200 and reduces noise according to the field environment. Therefore, the PAPR of the summed signal due to the digital filtering sum is reduced, and the digital predistortion and the digital signal are processed.

Here, the FPGA unit 300 detects FA information among optical signals transmitted from the digital optical module 200 through the FA detector 310, and detects noise of a signal according to a field environment through the FA filter unit 320. In order to reduce the filtering, the signal is filtered by FA. In addition, the CFR unit 330 performs filtering to reduce the level of a signal exceeding a threshold value among the signals input from the FA filter units 320 through filtering.

At this time, the peak power component exceeding the threshold value is reduced without deterioration of signal characteristics by the above-described scale process, thereby effectively reducing the PAPR. Therefore, as the PAPR is reduced, the power consumption rate is lowered, the use of devices such as transistors is reduced, and the configuration of low capacitance is possible, but the output signal of the same level is obtained.

In addition, the FPGA unit 300 predistorts the signal for linearization of the large power amplifier 500 through the DPD unit (Digital Pre-Distortion, 340), and through the DSP unit (Digital Signal Processor, 350) which is a digital signal processor. Performs the digital signal arithmetic processing according to the digital predistortion.

Meanwhile, the DAC unit 400 converts the digital signal input from the FPGA unit 300 into an analog signal and outputs the analog signal.

The uplink frequency converter 450 up-converts the analog signal of the intermediate frequency band input from the DAC unit 400 to the RF signal and outputs the RF signal.

The large power amplifier 500 power amplifies and outputs the RF signal input from the uplink frequency converter 450.

The downlink frequency converter 550 down-converts the RF signal coupled from the output terminal of the large power amplifier 500 to an intermediate frequency band for linearization.

The ADC unit 600 converts the signal of the intermediate frequency band input from the downlink frequency converter 550 into a digital signal and outputs the digital signal to the FPGA unit 300 for predistortion linearization.

The CPU unit 650 processes the information transmitted from the digital optical module 200 and the FPGA unit 300, and transmits a command transmitted from the main hub unit (MHU) through the digital optical module 200 to the FPGA unit 300. ) And the digital optical module 200, or the alarm / data information of the FPGA unit 300 and the digital optical module 200 are upwardly transmitted to the main hub unit (MHU) through the digital optical module 200.

The low noise amplifier 700 amplifies and outputs a low noise amplified signal from the duplexer D in the reverse link.

The downlink frequency converter 750 down-converts the signal input from the low noise amplifier 700 to the intermediate frequency band and outputs the signal to the ADC 800.

The ADC 800 converts the analog signal input from the downlink frequency converter 750 into a digital signal and outputs the digital signal to the digital optical module 200.

The remote optical unit ROU1 of the present invention having the above-described structure includes an FPGA unit in which the FA detection unit 310, the FA filter unit 320, the CFR unit 330, the DPD unit 340, and the DSP unit 350 are programmable semiconductors ( The integrated modularity of 300) enables the implementation of optimized circuits, reduces the number of circuit components, and reduces power consumption.

In particular, since the remote optical unit ROU1 of the present invention applies the CFR unit 330 to the FPGA unit 300, the increase in the PAPR reduces the use of devices such as transistors, thereby realizing cost reduction and miniaturization of the product. In addition, it is possible to obtain an output signal having the same level while having a low capacitance structure. Therefore, it is possible to greatly improve the equipment quality and performance of the microwave repeater to which the remote optical unit ROU1 is applied.

In addition, since the low noise amplifier 700 and the downlink frequency converter 750 are modularized in the ROU integrated module 100, the remote optical unit ROU1 of the present invention reduces the appearance while enabling an optimized circuit design and a path according to the modularization. It is possible to prevent signal interference between paths by improving the isolation of the liver.

Furthermore, since the remote optical unit ROU1 of the present invention directly inputs the signal from the ADC unit 800 in the reverse link process to the digital optical module 200, the circuit structure can be simplified, power consumption can be reduced, and product miniaturization can be realized. Can be.

Meanwhile, FIG. 3 illustrates an example in which the connected remote optical unit ROU1 and the terminated remote optical unit ROU2 are installed together as another embodiment of the present invention.

The terminal type remote optical unit ROU2 of the present invention differs in that it does not include the optical switch 150 as compared with the connection type remote optical unit ROU1 shown in FIGS. 2 and 3. The same is true for most configurations. Therefore, since the detailed configuration, operation and effects of the end-type remote optical unit ROU2 are the same as those of the connected remote optical unit ROU1, detailed description thereof will be omitted.

As described above, the embodiments of the present invention are merely illustrative of preferred examples, and the scope of application of the present invention is not limited thereto, and may be appropriately changed within the scope of the same idea.

1 is a block diagram showing a conventional remote optical unit.

2 is a block diagram illustrating a remote optical unit in accordance with the present invention.

3 is a block diagram illustrating a remote optical unit according to another exemplary embodiment of the present disclosure.

<Description of Symbols for Main Parts of Drawings>

100,101: ROU integrated module 150: optical switch

200,201: digital optical module 300: FPGA unit

310: FA detection unit 320: FA filter unit

330: CFR unit 340: digital predistortion unit

350: DSP unit 400: DAC unit

450: up-frequency converter 500: large power amplifier

550: downlink frequency converter 600: ADC unit

650 CPU 700: Low Noise Amplifier

750: downlink frequency converter 800: ADC unit

D: Duplexer MHU: Main hub unit

ROU1, ROU2: Remote Optical Unit

Claims (5)

In the remote optical unit including a ROU integration module 100 to reduce the PAPR and perform digital predistortion through the CFR in the process of outputting the signal input from the main hub unit (MHU) to the duplexer (D), the ROU integration Module 100, An optical switch 150 which transmits and receives an optical signal to and from the main hub unit MHU; A digital optical module 200 which transmits and receives an optical signal with the optical switch 150; An FPGA unit 300 which transmits and receives a signal with the digital optical module 200 and reduces PARR through CFR and performs digital predistortion and digital signal processing; A DAC unit 400 for converting a digital signal input from the FPGA unit 300 into an analog signal and outputting the analog signal; An uplink frequency converter 450 for upconverting and outputting a signal input from the DAC unit 400; A large power amplifier 500 for power amplifying the signal input from the uplink frequency converter 450 and outputting the amplified signal to the duplexer D; A downlink frequency converter 550 for down-converting and outputting the signal coupled from the output terminal of the large power amplifier 500; An ADC unit 600 for converting a signal input from the downlink frequency converter 550 into a digital signal and outputting the digital signal to the FPGA unit 300; A CPU unit 650 for processing the information transmitted from the digital optical module 200 and the FPGA unit 300 and transmitting the information to the optical module 200 and the FPGA unit 300; A low noise amplifier 700 for low noise amplifying and outputting a signal input from the duplexer D; A downlink frequency converter 750 for down-converting and outputting the signal input from the low noise amplifier 700; An ADC unit 800 for converting an analog signal input from the downlink frequency converter 750 into a digital signal and outputting the digital signal to the digital optical module; Remote light unit consisting of. delete The method of claim 1, wherein the optical switch 150, The optical signal input from the main hub unit (MHU) is switched to the digital optical module 201 of the remote optical unit ROU2 different from the digital optical module 200 and outputted, and from the digital optical module 200, 201. Remote optical unit for switching the input signal output to the main hub unit (MHU). In the remote optical unit including a ROU integration module 100 to reduce the PAPR and perform digital predistortion through the CFR in the process of outputting the signal input from the main hub unit (MHU) to the duplexer (D), the ROU integration Module 100, A digital optical module 201 which transmits and receives an optical signal to and from the main hub unit MHU; The signal is transmitted and received with the digital optical module 200, and the PARR is reduced through CFR and performs digital predistortion and digital signal processing, and FA detects FA information among optical signals transmitted from the digital optical module 200. Detection unit 310, FA filter unit 320 for filtering the signal for each FA in order to reduce the signal noise according to the field environment, and the signal exceeding the threshold value of the signal input from each FA filter unit 320 CFR unit 330 for reducing and outputting PAPR, digital predistortion unit 340 for predistorting signals for linearization of large power amplifier 500, and DSP for performing arithmetic processing of digital signals according to digital predistortion An FPGA unit 300 formed of a unit 350; A DAC unit 400 for converting a digital signal input from the FPGA unit 300 into an analog signal and outputting the analog signal; An uplink frequency converter 450 for upconverting and outputting a signal input from the DAC unit 400; A large power amplifier 500 for power amplifying the signal input from the uplink frequency converter 450 and outputting the amplified signal to the duplexer D; A downlink frequency converter 550 for down-converting and outputting the signal coupled from the output terminal of the large power amplifier 500; An ADC unit 600 for converting a signal input from the downlink frequency converter 550 into a digital signal and outputting the digital signal to the FPGA unit 300; A CPU unit 650 for processing the information transmitted from the digital optical module 200 and the FPGA unit 300 and transmitting the information to the optical module 200 and the FPGA unit 300; A low noise amplifier 700 for low noise amplifying and outputting a signal input from the duplexer D; A downlink frequency converter 750 for down-converting and outputting the signal input from the low noise amplifier 700; An ADC unit 800 for converting an analog signal input from the downlink frequency converter 750 into a digital signal and outputting the digital signal to the digital optical module; Remote light unit consisting of. The method of claim 1 or 3, wherein the FPGA unit 300, A FA detector 310 for detecting FA information among optical signals transmitted from the digital optical module 200; A FA filter unit 320 for filtering signals for each FA to reduce signal noise according to a field environment; A CFR unit 330 for reducing and outputting a PAPR of a signal exceeding a threshold value among signals input from each FA filter unit 320; A digital predistorter 340 for predistorting a signal for linearization of the large power amplifier 500; DSP unit 350 for performing arithmetic processing of digital signals according to digital predistortion Remote light unit consisting of.

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