KR101133747B1 - Apparatus and method for transmitting data in a terminal of satellite communication system - Google Patents

Abstract

The present invention relates to an apparatus and method for transmitting data in a terminal of a wireless communication system, and more particularly, to an apparatus and method for transmitting data in a terminal of a satellite communication system.

An apparatus according to an embodiment of the present invention is a data transmission apparatus of a satellite communication system, and modulates and synthesizes an in-phase (I) signal and a quadrature (Q) signal into an intermediate frequency signal, respectively, and amplifies the synthesized signal. And a base signal processor for extracting a predetermined band, and separating a phase component and an amplitude component from the extracted signal, up-converting the separated phase component to a band of a frequency band for satellite communication, and then limiting it to a preset amplitude. And a transmission signal processing unit for amplifying the separated amplitude component and the amplitude limited phase component into a predetermined gain value and outputting the combined amplitude component as a signal of a band for transmission to a satellite, wherein the transmission signal processing unit comprises: An amplitude processor for extracting and amplifying the amplitude component from the signal output from the base signal processor, and the separated phase component. A phase processor for upconverting to a band of a frequency band for satellite communication and limiting to a predetermined amplitude and amplifying the amplitude limited phase component to a predetermined gain value, the amplitude signal amplified by the amplitude processor and the phase processor It includes a combiner for coupling the phase signal amplified in.

Out-Door Unit (ODU), In-Door Unit (IDU), Polar Transmitter

Description

Apparatus and method for transmitting data from a terminal of a satellite communication system {APPARATUS AND METHOD FOR TRANSMITTING DATA IN A TERMINAL OF SATELLITE COMMUNICATION SYSTEM}

The present invention relates to an apparatus and method for transmitting data in a terminal of a wireless communication system, and more particularly, to an apparatus and method for transmitting data in a terminal of a satellite communication system.

"The present invention is derived from the research carried out as part of the development project of the Korea Communications Commission and Korea Electronics and Telecommunications Research Institute [Task No. 2009-F-039-01, Title: Development of core technology for high efficiency satellite return link connection] . "

In general, satellite communication is a communication method for relaying signals by satellites that are launched in a certain air space outside the atmosphere. In other words, the communication satellite acts as a microwave repeater floating in the sky.

Satellite communication transmits a radio wave to a communication satellite when transmitting a radio wave from the ground so that a signal can be transmitted to other users on the ground. A communication satellite receives radio waves transmitted from the ground, converts and amplifies frequencies, and transmits them to the ground again. The reason why the frequency transmitted from the ground and the frequency transmitted from the satellite is different is to avoid interference of up and down signals.

The earth station is the place that acts to lift the radio wave toward the satellite and receive the radio wave from the ground that the satellite re-shoots. In actual communication, the sender first sends a signal to the earth station, and the earth station sends the signal to the satellite. The satellite receives the radio wave emitted from the earth station, converts the frequency, amplifies it, and sends it back to the earth station. The earth station sends the signal received from the satellite to the other party, the final destination, so that the sender's signal reaches the receiver.

The types of satellites are classified according to their position. Geostationary Earth Orbit (GEO) at the same orbit (about 36,000 km altitude) on Earth's rotation cycle, Middle Earth Orbit (MEO) at altitudes of 5,000 to 25,000 km, altitude 300 to 1500 km Low Earth Orbits (LEOs) located at, and High Earth Orbits (HEOs) with elliptical periods.

The advantage of satellite communication is that it can use large bandwidth to communicate large capacity, low communication cost and improved line quality. In addition, the use of satellite communication increases the communicable area and enables high-speed transmission using high frequency radio waves. Since satellite communication uses microwaves, high-speed and large-capacity communication is possible, and large areas can be used as communication areas. In addition, normal (even) communication is possible regardless of the terrain, and even if a disaster occurs, communication is not restricted.

In other words, the advantages of satellite communication are broadcasting, wide area, flexibility and speed of circuit setting, and disaster resistance.

Broadcasting means that the same information can be transmitted to multiple recipients at the same time, and wide area means that one satellite can cover about one-third of the earth's surface, allowing communication over a large area. The flexibility and speed of circuit setup means that communication lines can be set up anywhere just by installing the earth station, and the earth station can be easily installed, added, removed, and moved. Disaster resistance means that there are few parts installed on the ground of the satellite communication system, so the impact of the ground disaster is very small.

1 is a block diagram of a general satellite communication system.

The remote earth station system includes an antenna unit 101, a transceiver (not shown), an orthomode transducer (OMT) 104, a Tx Reject Filter (TRF) 105, and a block up converter (BUC) 107. ), An outdoor unit (ODU) equipment 100 including a low noise block (LNB) 109, and an indoor unit in a set-top-box (STB) type. Door Unit (IDU) equipment 110 is divided into.

The antenna unit 101 of the outdoor unit (ODU) 100 is a device that transmits and receives a communication satellite and a data signal, and is composed of a reflector plate 102 and a feed horn 103 having an arbitrary radius. In addition, the transceiver of the outdoor unit (ODU) 100 converts the frequency of the L band (Band) to the Ku band (Band) frequency, and serves to increase the output power.

In addition, the indoor unit (IDU) 110 is a set-top box (Set-top-box) 112 is composed of a modem and a power supply.

Applications of such satellite communication include international telephony relay network and remote medical care using broadband transmission, personal mobile communication in the field of mobile communication, aeronautical mobile communication, and maritime communication. It also includes flood control and forecasting, river monitoring, meteorological observations and air quality measurements using remote monitoring and control functions.

In addition, satellite communication is very advantageous for communication between books, wallpaper, and mobile devices, and satellite broadcasting can solve TV blind spots in mountain walls or urban building areas, and can provide a variety of high-quality services.

Recently, satellite communication has attracted attention as an attractive means of next-generation personal communication services, and among them, communication methods using low or mid-orbit are being actively promoted.

Satellite communication technology requires a terminal structure in the form of a portable terminal for use in disaster / disaster communication networks and military operations. In order to develop a portable terminal for satellite communication, the terminal must operate using a battery, and a technique for reducing power consumption of the terminal is required for a long time operation.

Accordingly, the present invention provides a transmission apparatus and method for data transmission in a terminal of a satellite communication system using a battery.

In addition, the present invention provides a transmission apparatus and method capable of long-term communication by increasing the efficiency of the transmitter in a portable satellite communication terminal.

An apparatus according to the present invention is a data transmission apparatus of a satellite communication system, and modulates an in-phase (I) signal and a quadrature (Q) signal into an intermediate frequency signal to synthesize them, amplifies the synthesized signal, and then determines a predetermined value. A base signal processor for extracting a band, separating a phase component and an amplitude component from the extracted signal, up-converting the separated phase component to a band of a frequency band for satellite communication, and then limiting to a preset amplitude; And a transmission signal processing unit for amplifying the separated amplitude component and the amplitude limited phase component into a predetermined gain value and combining and outputting the combined amplitude component as a signal of a band for transmission to a satellite, wherein the transmission signal processing unit comprises: the base signal processing unit An amplitude processing unit for extracting and amplifying an amplitude component from a signal output from A phase processor for up-converting to a band of a frequency band for a predetermined amplitude and amplifying the amplitude limited phase component to a predetermined gain value, an amplitude signal amplified by the amplitude processor and amplified by the phase processor And a combiner for coupling the phase signal.

In addition, the method according to the present invention is a method for transmitting data in a satellite communication system, generating a signal for modulating an in-phase (I) signal and a quadrature (Q) signal into a predetermined intermediate frequency band, and generating the signal. Modulate the in-phase signal and the quadrature signal by using the received signal, synthesize the modulated in-phase signal and the quadrature signal, amplify the synthesized signal to a predetermined gain value, and then apply a predetermined band. Extracting, separating a phase component and an amplitude component from the extracted signal, mixing the separated phase component with a signal of a frequency band generated for transmission to a satellite, up-converting the frequency, and limiting it to a predetermined amplitude Amplifying the amplitude limited phase signal to a predetermined gain value, extracting the separated amplitude component Amplifying the amplitude signal with a predetermined gain value, and combining the amplified amplitude signal with the amplified phase signal.

Applying the present invention, there is an advantage that can increase the efficiency of a high power consumption transmitter in the satellite communication of the terminal type.

The above objects, features, and advantages will be described in detail with reference to the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. In describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of an apparatus for transmitting data in a terminal of a satellite communication system according to an embodiment of the present invention, and shows a configuration of a high efficiency transmission apparatus for satellite communication.

The satellite communication terminal includes a base signal processor 200 and a transmission signal processor 230. The base signal processor 200 generates a modulated signal in an intermediate frequency (IF) signal band, and the transmit signal processor 230 has a structure of frequency up-converting the modulated signal into a radio frequency (RF) signal.

The base signal processor 200 includes a modulator 201, a switching power amplifier 222, and a TXF 224.

The modulator 201 includes two digital-to-analog converters 202 and 203, an I / Q modulator 204, and a local oscillation frequency generator 208.

When the transmitter is operated, the base signal processor 200 generates a baseband signal in a digital form by an internal modem (not shown). At this time, the modem generates a baseband signal by separating into I (n), which is an in-phase component of baseband digital data, and Q (n), which is a quadrature component. The generated digital baseband signals I (n) and Q (n) are converted to analog baseband signals I (t) and Q (t) through respective digital-to-analog converters (D / A) 202 and 203. Is converted.

The I / Q modulator 204 receives the converted analog baseband signals I (t) and Q (t) and performs phase modulation. I / Q modulator 204 uses two orthogonal signals, I (in-phase) and Q (quadrature), to produce a single complex waveform.

I / Q modulator 204 includes two RF up frequency mixers 205 and 207 to convert each quadrature input signal to an RF carrier frequency. Of the analog baseband signals I (t) and Q (t) converted by the digital-to-analog converters 202 and 203, I (t) is provided to the I-up frequency mixer 205 and Q (t). To the Q-uplink frequency mixer 207.

The local oscillation frequency generator 208 includes a phase locked loop (PLL) 212, a local oscillator 214, three amplifiers 209, 210, and 216, and a divider 218. .

Phase locked loop (PLL) 212 is a frequency negative feedback circuit configured to keep the frequency of the output signal constant at all times, such that the signal is held at a particular phase. In other words, the correct fixed point is forcibly held so that the phase of the periodic signal is not shaken. In particular, the present invention is used to prevent the shaking of the frequency used as a frequency source.

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라 할 수 있다.Local oscillator 214 supplies local oscillation frequencies for frequency synthesis to I-up frequency mixer 205 and Q-up frequency mixer 207. The local oscillator 214 may be configured in two, and the outputs of the two local oscillators have a phase difference of 90 degrees. For example, each output

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The amplifier 216 amplifies a signal having a phase difference of 90 degrees generated by the local oscillator 214, and then divides the amplified signal into two signals, I and Q axes, through the divider 218.

The I-axis local oscillation frequency is amplified by the amplifier 209 and multiplied by the I-up frequency mixer 205 to upconvert the I-axis signal to the intermediate frequency IF. In addition, the Q-axis local oscillation frequency is amplified by the amplifier 210 and multiplied by the Q-uplink frequency mixer 207 to up-convert to the intermediate frequency.

The signal synthesizer 220 combines the I (t) and Q (t) signals upconverted to the intermediate frequency into a signal containing a phase signal.

The switching power amplifier 222 amplifies the combined signal from the signal synthesizer 220. The switching power amplifier 222 varies the power supply voltage to generate an envelope signal. That is, the power of the transmitting device provided as a bias of the switching power amplifier 222 is used to control the output size of the switching power amplifier 222.

The TXF 224 is a band band filter and receives a signal output from the switching power amplifier 222 and passes only a predetermined channel frequency band. The signal passing through the filter is input to the transmission signal processor 230.

The transmission signal processor 230 is configured to separate the signal (a) input from the base signal processor 200 into an amplitude component and a phase component, amplify each of them, and transmit the sum.

The structure of the transmission signal processor 230 according to the present invention uses a polar transmitter conversion scheme to convert the modulation signals I and Q data of the intermediate frequency signal band into amplitude data and phase data.

In general, the polar transmitter is a structure that separates the amplitude and phase signals from the baseband digital signal, and amplifies and combines them through a switching PA.

The transmission signal processor 230 according to the present invention includes an amplitude processor 231, a phase processor 240, and a combiner 260.

The amplitude processor 231 includes an envelope detector 232 and a power amplifier 233. The phase processor 240 includes a phase locked loop (PLL) 242, a local oscillator 244, an amplifier 246, an up frequency mixer 248, a limiter 250, and a power amplifier 252. do.

The envelope detector 232 detects only an amplitude component from a signal (reference numeral a) input to the transmission signal processor 230, and a waveform passing through the envelope detector 232 is as shown in (b). The power amplifier 233 receives the amplitude signal output from the envelope detector 232 and amplifies the signal to a predetermined gain value.

The phase component in the signal (reference numeral a) input to the transmission signal processor 230 up-converts the frequency of the L band to the Ku band by the phase processor 240.

The phase locked loop (PLL) 242 forcibly grasps an accurate fixed point so that the phase of the periodic signal does not shake, thereby keeping the frequency constant at all times. Therefore, in the present invention, it is used to prevent the shaking of the frequency used as the frequency source.

The local oscillator 244 supplies a local oscillation frequency for frequency synthesis to the uplink mixer 248. The amplifier 246 amplifies the signal generated by the local oscillator 244 and then up-converts the frequency of the L band (Band) to the Ku band (Band) frequency by multiplying the up-frequency mixer 248.

The up-converted signal proceeds through the limiter 250 to maintain the signal of phase modulation PM before being supplied to the power amplifier 252. The limiter 250 is used to remove the amplitude component from the modulated signal and input it to the power amplifier 252. The waveform passing through the limiter 250 is equal to (c) and is input to the power amplifier 252 and amplified to a predetermined gain value.

The combiner 260 receives and combines the amplified amplitude signal output from the amplitude processor 231 and the phase signal up-converted to the Ku band frequency through the phase processor 240.

3 is a block diagram of an apparatus for transmitting data in a terminal of a satellite communication system according to another embodiment of the present invention, showing the configuration of a high efficiency transmission apparatus for satellite communication.

The configuration of the base signal processor 200 of the transmitter of FIG. 3 is the same as that of FIG. 2, and the parts of the phase processor 310 of the transmitter signal processor 300 are different. In particular, only the position of the limiter 320 of the phase processor 310 is incorrect. That is, in FIG. 2, the limiter 250 is positioned after the uplink mixer 248, but in the configuration of FIG. 3, the limiter 320 is located in front of the uplink mixer 318.

In FIG. 3, a phase component in a signal (reference numeral a) input to the transmission signal processing unit 300 passes through the limiter 320 to protect a phase modulated signal. Limiter 320 generates a limited transmit signal having a limited amplitude and the same phase as the input phase signal. The phase locked loop (PLL) 312 is used to prevent the shaking of the frequency used as the frequency source. The local oscillator 314 supplies a local oscillation frequency for frequency synthesis to the uplink frequency mixer 318. The amplifier 316 amplifies the signal generated by the local oscillator 314, and the amplified signal is multiplied by the uplink mixer 318 so that the frequency of the L band (Band) is up-converted to the Ku band (Band) frequency. do.

Since the power amplifier 322 amplifies only a signal having a phase component, the efficiency of the power amplifier 322 may be increased.

The combiner 260 receives and combines the amplified amplitude signal output from the amplitude processor 231 and the phase signal up-converted to the Ku band frequency through the phase processor 310.
While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

1 is a configuration diagram of a general satellite communication system,

2 is a block diagram of an apparatus for transmitting data in a terminal of a satellite communication system according to an embodiment of the present invention;

3 is a block diagram of an apparatus for transmitting data in a terminal of a satellite communication system according to another embodiment of the present invention.

Claims (7)

In the data transmission apparatus of the satellite communication system, A base signal processor which modulates the in-phase (I) signal and the quadrature (Q) signal into an intermediate frequency signal, respectively, synthesizes the amplified signal, and then amplifies the synthesized signal and extracts a predetermined band; Separating a phase component and an amplitude component from the extracted signal, up-converting the separated phase component to a band of a frequency band for satellite communication, and then limiting it to a preset amplitude, and the separated amplitude component and the amplitude limited phase And a transmission signal processor for amplifying the components to a predetermined gain value and outputting the combined signals as signals of a band for transmission to a satellite. The transmission signal processing unit, An amplitude processor for extracting and amplifying an amplitude component from the signal output from the base signal processor; A phase processor configured to up-convert the separated phase component to a band of the frequency band for the satellite communication and then limit it to a predetermined amplitude, and amplify the amplitude limited phase component to a predetermined gain value; A combiner for combining the amplitude signal amplified by the amplitude processor and the phase signal amplified by the phase processor Apparatus for transmitting data in the terminal of the satellite communication system comprising a. The method of claim 1, wherein the base signal processor, A modulator for generating a signal for modulating the in-phase signal and the quadrature signal into a predetermined intermediate frequency band, and modulating the in-phase signal and the quadrature signal by using the generated signal; A switching power amplifier for amplifying the signal modulated by the modulator to a predetermined gain value; A filter for extracting a signal of a predetermined band from the signal amplified by the switching power amplifier Apparatus for transmitting data in the terminal of the satellite communication system comprising a. The method of claim 2, wherein the modulator, A digital analog converter for converting the in-phase signal and the quadrature signal into an analog signal; A local oscillation frequency generator for generating two local oscillation frequencies having a phase difference of 90 degrees; I / Q modulator for synthesizing the in-phase and quadrature signals converted from the digital-to-analog converter into analog signals with local oscillation frequency signals generated by the local oscillation frequency generator Apparatus for transmitting data in the terminal of the satellite communication system comprising a. delete The method of claim 1, wherein the amplitude processing unit, An envelope detector for extracting an amplitude component from the signal output from the base signal processor; An amplifier for amplifying the amplitude component extracted by the envelope detector to a predetermined gain value Apparatus for transmitting data in the terminal of the satellite communication system comprising a. The method of claim 1, wherein the phase processing unit, A mixer for up-converting a frequency by mixing a signal of a phase component output from the base signal processor and a signal of a frequency band generated for transmission to the satellite; A limiter for limiting the output of the frequency up-converted phase signal in the mixer to a preset amplitude; An amplifier amplifying the amplitude limited phase signal to a predetermined gain value in the limiter Apparatus for transmitting data in the terminal of the satellite communication system comprising a. In a method for transmitting data in a satellite communication system, Generating a signal for modulating an in-phase (I) signal and a quadrature (Q) signal into a predetermined intermediate frequency band, and modulating the in-phase signal and the quadrature signal using the generated signal, respectively Synthesizing a modulated in-phase signal and a quadrature signal, amplifying the synthesized signal to a predetermined gain value, and extracting a predetermined band; Separating a phase component and an amplitude component from the extracted signal; Mixing the separated phase component with a signal of a frequency band generated for transmission to a satellite, frequency upconverting and limiting the signal to a predetermined amplitude, and amplifying the amplitude limited phase signal to a predetermined gain value; Extracting the separated amplitude components and amplifying the amplitude signal with a predetermined gain value; Combining the amplified amplitude signal with the amplified phase signal And transmitting the data at the terminal of the satellite communication system.

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