KR20190051115A - Apparatus for receiving modulated beacon signals, Method thereof, and Computer readable storage media having the method - Google Patents

Abstract

The present invention relates to a technology for receiving a modulated beacon signal and, more specifically, to a method and an apparatus for receiving a modulated beacon signal, wherein a modulated beacon performs dispreading after correcting a coarse frequency offset (FO), a fine FO, and a phase offset at once using a two-phase pulse-shaping characteristic in a baseband transform unit.

Description

FIELD OF THE INVENTION The present invention relates to a modulated beacon signal receiving apparatus, a method thereof, and a computer readable storage medium storing the method.

The present invention relates to a modulation beacon signal receiving technique, and more particularly, to a coherent FO (frequency offset), fine (fine) FO, and phase offset at a time, and performs despreading on the modulated beacon signal.

(n은 자연수) 포인트 FFT(Fast Fourier Transform) 변환하는 FFT부, 상기 각 포인트의 값의 크기를 비교하여 가장 큰 값의 FFT 포인트를 추출하는 CW(Continuous Wave) 성분 추출부 및 상기 추출된 FFT 포인트의 값을 이용해 상기 변조 비콘 신호의 반송파 주파수를 동기화시키는 주파수 동기부를 포함한 기술이다.The existing technology (Korean Patent Publication No. 10-2012-0114823) is a modulation beacon using a modulated beacon waveform formed by two-phase pulse shaping of a power spreading code without including a pilot signal in a limited channel environment such as satellite communication. Signal

(Continuous Wave) component extracting unit for extracting an FFT point having the largest value by comparing the magnitudes of the values of the respective points, and a FFT unit for performing FFT (Fast Fourier Transform) And a frequency synchronization unit for synchronizing a carrier frequency of the modulated beacon signal using a value of the frequency synchronization unit.

However, the method of synchronizing the carrier frequency of the modulated beacon signal using the FFT, which is the core of the existing technology, must set the value of n to 10 in order to operate stably. In this case, there are a total of 1024 FFT points, which not only increases delay and complexity in terms of system implementation but also increases the frequency offset (FO) between points and the Doppler shift rate (Hz) / s), a separate circuit for correcting the phase difference due to the phase offset must be implemented.

1. Korean Patent Publication No. 10-2012-0114823 2. Korean Registered Patent No. 10-0780117 (November 21, 2007) 3. Korean Patent Publication No. 10-2012-0114823

The present invention has been proposed in order to solve the above problem, and it is an object of the present invention to provide a coarse FO (Frequency Offset), fine the present invention provides a modulation beacon signal receiving apparatus and method for correcting a fine FO and a phase offset at a time and performing despreading.

In order to achieve the above-described object, the present invention provides a method of converting a modulated beacon transmission signal into a coarse FO (frequency offset), a fine FO, a phase And corrects the phase offset at one time and performs despreading.

Wherein the modulation beacon signal receiving device comprises:

 A baseband transformer for correcting a received modulation beacon transmission signal through a characteristic of a modulation beacon spread by Bi-phase coding to generate a corrected analog signal;

A digital converter for converting the analog signal into a digital signal; And

And a despreader for despreading the digital signal to generate a final output signal.

In this case, the correction may be any one of a coarse frequency offset, a fine frequency offset, and a phase offset.

In addition, the modulation beacon transmission signal may include a CW (Continuous Wave) beacon signal and a modulation beacon signal.

The modulation beacon signal may include a beacon signal carrier frequency, beacon modulation data, and a beacon spread signal, and the beacon spread signal may use two-phase coding.

The characteristic of the spread modulation beacon is that if chip synchronization is performed in a sequence indicating two-phase encoding as a constellation rotates due to the presence of a frequency offset, if a plurality of symbols are successively accumulated, The magnitude value becomes maximum when the frequency offset is minimum and the angle of the maximum value vector at the frequency is the characteristic that the constellation of the intermediate chip in the accumulation chip section is the rotation value .

In addition, the plurality of symbols may be a half chip unit.

Also, the constellation rotation value may be a rotation angle of the intermediate symbol in the cumulative interval of the vector.

Also, the accumulation may be performed on a symbol-by-symbol basis regardless of whether the chip is synchronized or not, and may be performed when the symbol synchronization is coincident.

In addition, if the chip synchronization does not match, accumulation is performed on M-1 symbols (where M is a multiple of 2) to perform phase correction on M / 2 symbols.

The baseband converter may further include: a local oscillator; A frequency varying unit for performing a plurality of local oscillations using the local oscillator; A plurality of demodulators for generating a plurality of demodulated signals by demodulating the modulated beacon transmission signals using the plurality of local oscillations, respectively; And a plurality of correlators for generating a plurality of analog signals by correcting the plurality of demodulated signals.

On the other hand, another embodiment of the present invention is a method for transmitting a modulated beacon transmission signal, comprising the steps of: (a) receiving a modulation beacon transmission signal; (b) generating a corrected analog signal by performing a correction on the modulated beacon transmission signal through a characteristic of a modulation beacon spread by the baseband converter by Bi-phase coding; (c) converting the analog signal into a digital signal; And (d) despreading the digital signal by a despreader to demodulate the digital signal to output a final signal.

On the other hand, another embodiment of the present invention can provide a computer-readable storage medium storing the program code for executing the above-described modulation beacon signal receiving method.

 According to the present invention, a coarse frequency offset, a fine FO, and a phase offset can be corrected at a time, thereby enabling more efficient hardware implementation.

Another advantage of the present invention is that it is expected to be applicable to a modulation beacon receiving apparatus used for satellite communication.

Further, the present invention is not limited to the above-mentioned effects, and may be variously extended without departing from the spirit and scope of the present invention.

1 is a graph showing the IQ phase of a general s (t) signal.
2 is a diagram illustrating a two-phase encoding according to a temporal example of the present invention.
3 is a graph illustrating a phase change estimation using a two-phase characteristic according to an embodiment of the present invention.
4 is a conceptual diagram illustrating an example of phase correction using 125 symbols (63 chips) according to an embodiment of the present invention.
5 is a configuration diagram of a modulation beacon receiving apparatus 500 according to an embodiment of the present invention.
FIG. 6 is a block diagram of the configuration of the baseband converter 510 shown in FIG.
FIG. 7 is a block diagram of the configuration of the first correction unit 620-1 shown in FIG.
FIG. 8 is a flowchart illustrating a process of receiving a beacon signal according to an embodiment of the present invention and processing it as a digital signal.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for similar elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term " and / or " includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Should not.

Hereinafter, an apparatus and method for receiving a modulated beacon signal according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a graph showing the I-Q phase of a general s (t) signal. Referring to FIG. 1, a modulation beacon signal includes a continuous wave (CW) beacon signal and a modulation beacon signal in a modulation beacon transmission signal as shown in the following equation.

는 비콘 신호 캐리어 주파수,

는 비콘 변조 데이터,

는 비콘 확산 신호이다. 또한,

(modulation index: 변조지수)에 의해 도 1에 도시된 바와 같이 I-위상(In-Phase), Q-위상(Quadrature-Phase)의 값이 변하며 변조 비콘은 Q-위상(Phase) 상에 존재한다. 비콘 확산 신호 PN(Pseudo random Noise)은 2위상(Bi-phase, Manchester) 코딩(coding)을 사용한다.Where C is the beacon signal power,

The beacon signal carrier frequency,

Beacon modulation data,

Is a beacon spreading signal. Also,

(In-Phase) and Q-phase (Quadrature-Phase) are changed by a modulation index (modulation index) as shown in FIG. 1, and a modulation beacon exists on a Q-phase . The beacon spread signal PN (Pseudo random noise) uses Bi-phase (Manchester) coding.

2 is a diagram illustrating a two-phase encoding according to an embodiment of the present invention. Referring to FIG. 2, a characteristic of a modulation beacon spread by bi-phase coding is used. As shown in FIG. 2, there are always +1 and -1 symbols in one chip due to Bi-phase coding. A PN clock 210 indicating a clock, a PN sequence 220 indicating a data signal, and a Split Phase Level (SPL) sequence 230 indicating a two-phase encoding are shown in FIG.

3 is a graph illustrating a phase change estimation using a two-phase characteristic according to an embodiment of the present invention. Referring to FIG. 3, if there is a frequency offset, the constellation is rotated.

Therefore, when chip synchronization is achieved using bi-phase encoding characteristics, when a plurality of symbols (1/2 chip units) are continuously accumulated, the magnitude value of a vector This is the maximum when the frequency offset is minimum. Therefore, the characteristic that the angle of the maximum value vector at the corresponding frequency is the constellation rotation value of the intermediate chip in the accumulation chip period is used.

Further, if the cumulative sum vector is calculated, it is possible to generate the rotation angle of the intermediate symbol in the accumulation section of the vector.

4 is a conceptual diagram illustrating an example of phase correction using 125 symbols (63 chips) according to an embodiment of the present invention. Referring to FIG. 4, the concept shown in FIG. 3 can be applied even when chip synchronization is not performed (symbol synchronization is consistent). The accumulation is made on a symbol basis, regardless of chip synchronization.

Referring to FIG. 4, for example, when 126 symbols (symbol) are 126 chips (63 chips), there are 126 symbols as follows, and an accumulation sum vector of the first section 410 for 125 (M-1) ) And then performs phase correction on the intermediate symbol 63 (M / 2).

The phase correction for the next 64th symbol is performed through the cumulative sum vector of the second section 420. [ The reason why 125 symbols are used instead of 126 symbols is considered because chip synchronization is not suitable. Therefore, in this case, up to two differences may occur between the number of +1 and the number of -1. .

The number of +1 or -1 is increased by one symbol in 125 symbols, but it is negligible because the influence on angle is small when multiple vectors are accumulated. That is, accumulation is performed on M-1 symbols irrespective of chip synchronization, and correction is performed on M / 2 symbols (M is a multiple of 2).

5 is a configuration diagram of a modulation beacon receiving apparatus 500 according to an embodiment of the present invention. 5, the modulation beacon receiving apparatus 500 includes a base band converter 510 for performing a correction on a received modulated beacon transmission signal to generate a corrected analog signal, a digital A transform unit 520, a despreader 530 for despreading and demodulating the digital signal, and the like.

The baseband transformer 510 performs a correction using a coarse FO (frequency offset), a fine frequency offset (FO), and a phase offset. The coarse frequency offset performs an approximate frequency offset, and the fine frequency offset performs a frequency offset more finely.

To explain further, symbols spread by Bi-phase coding always have +1 and -1 symbols in 1chip. It can also be seen from SPL (Split Phase Level) shown in the figure. In addition, the coarse frequency offset and the fine frequency offset cause a constant rotation on the constellation, so the +1 and -1 in one chip rotate together.

Therefore, it can be estimated that the rotation angle of M-1 cumulative vectors is the M / 2th rotation angle. Incidentally, there is a fine FO / phase offset correcting section (620-1 to 620-n in FIG. 6) in the configuration of the baseband transforming section 510. In this part, M- / 2 < th > rotation angle, and the rotation value is conjugated and multiplied to restore the original constellation. The coarse frequency offset can be corrected through the selector 630 for finding a value having a maximum value among the restored values for each of the N coarse frequencies.

The digital converter 520 performs an ADC by dividing a dual channel ADC, that is, an in-phase and a quadrature phase. (D (t) is present in the quadrature phase) by the digital converter to despread the quadrature phase component.

FIG. 6 is a block diagram of the configuration of the baseband converter 510 shown in FIG. Referring to FIG. 6, the (N-1) local oscillator 601 is connected to the first to the n-th frequency shifters 600-1 to 600-n using a local oscillator 601, N) through the first to the n-th demodulators 610-1 to 610-n, and outputs the demodulated signals to the first to nth corrector units 620-1 to 620-n, respectively, And the selector 630 selects the path of the cumulative vector maximum value.

The first through the n-th demodulators 610-1 through 610-n in the baseband transform unit 510 are quadrature demodulators which are general quadrature demodulators and generate IQs using a local oscillator 601 and a reception signal. And performs integration and downsampling after conversion to a baseband frequency for each channel.

On the other hand, the demodulator of the baseband transformer 510 can lower the high frequency to the baseband frequency as in a general demodulator, and can view the constellation and correct the fine / phase offset accordingly. D (t) * PN (t) is obtained by multiplying the quadrature phase component extracted by the A / D converter 520 into the despreader 530 and multiplying the quadrature phase component by the PN (t) ) * PN (t) * PN (t) Since PN (t) * PN (t) = 1 ) * PN (t) = D (t). This can be called demodulation in the despreading unit.

FIG. 7 is a block diagram of the configuration of the first correction unit 620-1 shown in FIG. Referring to FIG. 7, correction is performed by a compensation method based on an accumulated value. That is, N result values are output through the N demodulators 610-1 to 610-n using a local oscillator 601 having N different frequencies and a modulation beacon transmission signal as a reception signal, (620-1 to 620-n). The sliding window integrator 710 of the corrector 620-1 accumulates M-1 consecutive symbols and then performs phase correction on the intermediate value M / 2 through the delay 720 and the complex multiplier 730 (M is a multiple of 2). A coarse frequency offset (coarse FO), a fine frequency offset (fine FO), and a phase offset (phase offset) are determined by determining one of the N values, which is phase-corrected using the mixer 740, ) At the same time. Although the first correction unit 620-1 is typically shown in Fig. 7, the other correction units also function in the same way.

FIG. 8 is a flowchart illustrating a process of receiving a beacon signal according to an embodiment of the present invention and processing it as a digital signal. Referring to FIG. 8, the baseband converter 510 receives a modulation beacon transmission signal (step S810).

Thereafter, the baseband converter 510 performs a correction on the modulation beacon transmission signal through the characteristics of the modulation beacon spread by bi-phase coding to generate a corrected analog signal ( Steps S820 and S830).

After that, the digital converter 520 converts the analog signal into a dual digital signal using In phase and quadrature phase components, and the despreader 530 despreads the digital signal to output a final signal (steps S840, S850).

The term " part " or the like, as described in the specification, means a unit for processing at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software.

(DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microprocessor, and the like, which are designed to perform the above- , Other electronic units, or a combination thereof. In software implementation, it may be implemented as a module that performs the above-described functions. The software may be stored in a memory unit and executed by a processor. The memory unit or processor may employ various means well known to those skilled in the art.

Furthermore, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied in the form of a program form which may be performed via a variety of computing means, and recorded in a computer-readable medium. The computer-readable medium may include a program (command) code, a data file, a data structure, and the like, alone or in combination.

The program (command) codes recorded on the medium may be those specially designed and constructed for the present invention or may be those known to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape, optical media such as CD-ROMs, DVDs, Blu-ray and the like, and ROMs, RAM), flash memory, and the like, which are specifically configured to store and execute program (instruction) codes.

Here, examples of program (command) codes include machine language codes such as those produced by a compiler, as well as high-level language codes that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

500: Modulation Beacon Signal Receiver
510:
520: Digital conversion unit
530:

Claims (12)

A baseband transformer for correcting a received modulation beacon transmission signal through a characteristic of a modulation beacon spread by Bi-phase coding to generate a corrected analog signal;
A digital converter for converting the analog signal into a digital signal; And
A despreader for despreading the digital signal to generate a final output signal;
And a demodulator for demodulating the modulated beacon signal.
The method according to claim 1,
Wherein the correction is any one of a coarse frequency offset, a fine frequency offset, and a phase offset.
The method according to claim 1,
Wherein the modulated beacon transmission signal comprises a CW (Continuous Wave) beacon signal and a modulation beacon signal.
The method according to claim 1,
Wherein the modulated beacon signal comprises a beacon signal carrier frequency, beacon modulated data, and a beacon spread signal, and the beacon spread signal uses two-phase coding.
3. The method of claim 2,
The spread modulated beacon is characterized in that when a chip is synchronized in a sequence indicating two-phase encoding as a constellation rotates due to the presence of a frequency offset, when a plurality of symbols are successively accumulated, magnitude value is maximum when the frequency offset is minimum and the angle of the maximum value vector at the frequency is the characteristic that the constellation of the intermediate chip in the accumulation chip period is the rotation value Wherein the modulation beacon signal receiving device comprises:
6. The method of claim 5,
Wherein the plurality of symbols is a half chip unit.
6. The method of claim 5,
Wherein the constellation rotation value is a rotation angle of an intermediate symbol in an accumulation section of the vector.
6. The method of claim 5,
Wherein the accumulation is performed on a symbol-by-symbol basis regardless of whether or not chip synchronization is performed, and when the symbol synchronization is coincident.
6. The method of claim 5,
And performs phase correction on M / 2 symbols by performing accumulation on M-1 symbols (where M is a multiple of 2) symbols if the chip synchronization is not matched.
The method according to claim 1,
Wherein the baseband transformer comprises:
One local oscillator;
A frequency varying unit for performing a plurality of local oscillations using the local oscillator;
A plurality of demodulators for generating a plurality of demodulated signals by demodulating the modulated beacon transmission signals using the plurality of local oscillations, respectively; And
And a plurality of correlators for correcting the plurality of demodulated signals to generate a plurality of analog signals.
(a) receiving a modulation beacon transmission signal by a baseband converter;
(b) generating a corrected analog signal by performing a correction on the modulated beacon transmission signal through a characteristic of a modulation beacon spread by the baseband converter by Bi-phase coding;
(c) converting the analog signal into a digital signal; And
(d) despreading the digital signal by despreading and performing demodulation to output a final signal;
And transmitting the modulated beacon signal to the base station.
     12. A computer-readable storage medium storing the program code for executing the modulation beacon signal receiving method of claim 11.

Images