WO2018016718A2

WO2018016718A2 - Apparatus and method for reducing peak to average power ratio in filter bank multicarrier system

Info

Publication number: WO2018016718A2
Application number: PCT/KR2017/003870
Authority: WO
Inventors: 최권휴; 라동준
Original assignee: 영남대학교 산학협력단
Priority date: 2016-07-20
Filing date: 2017-04-10
Publication date: 2018-01-25
Also published as: KR101807193B1; WO2018016718A3

Abstract

Disclosed are an apparatus and a method for reducing a peak to average power ratio (PAPR) in a filter bank multicarrier system. A transmission apparatus according to an embodiment of the present invention comprises: a discrete Fourier transform (DFT) unit for generating DFT-spread data symbols by performing an N-point (N is the number of subcarriers) DFT on parallel data symbols; a sign inversion unit for generating first data symbols by applying a first sign inversion rule to the DFT-spread data symbols, and generating second data symbols by applying a second sign inversion rule, which is different from the first sign inversion rule, to the DFT-spread data symbols; a modulation unit for generating a first transmission candidate signal and a second transmission candidate signal by modulating the first data symbols and the second data symbols according to a filter bank multicarrier (FBMC)/offset quadrature amplitude modulation (OQAM) scheme, respectively; and a selection unit for measuring a peak value or a peak to average power ratio (PAPR) of the first transmission candidate signal and the second transmission candidate signal, selecting a transmission signal having the smaller peak value or smaller PAPR among the first transmission candidate signal and the second transmission candidate signal, and transmitting the selected transmission signal.

Description

Apparatus and method for reducing peak-to-average power ratio in filterbank multicarrier systems

Embodiments of the present invention relate to a transmission / reception technique using a filterbank multicarrier technique, and more particularly, to an FBMC / OQAM technique using DFT spreading.

As a modulation technology for fifth generation mobile communication, a filter bank multi-carrier (FBMC) modulation technology using a plurality of subcarriers has been attracting attention. However, the FBMC modulation technique has a high peak to average power ratio (PAPR) due to the overlap of a plurality of subcarrier signals.

In particular, the Offset Quadrature Amplitude Modulation (FBMC / OQAM) technique produces a single carrier effect due to the structural problem of OQAM even when the Discrete Fourier Transform (DFT) spread is applied like the Single Carrier-Frequency Division Multi Access (SC-FDMA) technique. There is no problem.

Embodiments of the present invention provide an apparatus and method for reducing peak-to-average power ratio (PAPR) in a filterbank multi-carrier system.

According to an embodiment of the present invention, a transmission apparatus includes a DFT unit configured to perform N-point (N is the number of subcarriers) -point Discrete Fourier Transform (DFT) on parallel data symbols to generate DFT spread data symbols; Applying a first sign inversion rule to the DFT spread data symbols to generate first data symbols, and applying a second sign inversion rule different from the first sign inversion rule to the DFT spread data symbols to generate a second data symbol. A code inversion unit for generating data symbols, each of the first data symbol and the second data symbol are modulated by a filter bank multicarrier (FBMC) / quadrature amplitude modulation (OQAM) scheme to generate a first transmission candidate signal and a second transmission candidate signal. A modulator for generating a; And measure a peak or peak-to-average power ratio (PAPR) for the first transmission candidate signal and the second transmission candidate signal, and measure the peak value or the peak of the first transmission candidate signal and the second transmission candidate signal. And a selector for selecting and transmitting a signal having a small peak-to-average power ratio (PAPR) as a transmission signal.

The code inverting unit inverts the imaginary code of the data symbols to be transmitted by the odd-numbered subcarriers of the DFT spread data symbols to generate the first data symbols, and real numbers of the data symbols to be transmitted by the odd-numbered subcarrier. The second data symbols may be generated by inverting a negative sign.

The code inverting unit inverts the imaginary code of the data symbols to be transmitted by the even-numbered subcarriers of the DFT spread data symbols to generate the first data symbols, and real numbers of the data symbols to be transmitted by the even-numbered subcarrier. The second data symbols may be generated by inverting a negative sign.

The selector may transmit information on a code inversion rule applied to the transmission signal together with the transmission signal.

According to an embodiment of the present invention, there is provided a method of generating DFT spread data symbols by performing N (where N is the number of subcarriers) -point Discrete Fourier Transform (DFT) on parallel data symbols. Generating first data symbols by applying a first code inversion rule to DFT spread data symbols, modulating the first data symbols by FBMC / Quadrature Amplitude Modulation (OQAM), and transmitting the first data symbols. Generating a candidate signal, generating second data symbols by applying a second code inversion rule different from the first code inversion rule to the DFT spread data symbols, and generating the second data symbols in an FBMC / OQAM scheme Generating a second transmission candidate signal by measuring a peak value or a peak-to-average power ratio (PAPR) for the first transmission candidate signal and the second transmission candidate signal. Step and selected as the first transmit signal and said second candidate the candidate transmission signal of the peak or the peak-to-average power ratio (PAPR) is a transmission signal to the small signal comprises the step of transmitting.

The generating of the first data symbols may include generating the first data symbols by inverting an imaginary code of data symbols to be transmitted by an odd-numbered subcarrier among the DFT spread data symbols and generating the second data symbols. The generating may include generating the second data symbols by inverting the real part codes of the data symbols to be transmitted by the odd subcarriers.

The generating of the first data symbols may include generating the first data symbols by inverting an imaginary code of data symbols to be transmitted by an even-numbered subcarrier among the DFT spread data symbols and generating the second data symbols. In the generating, the second data symbols may be generated by inverting the real part code of the data symbols to be transmitted by the even subcarrier.

The transmitting may include transmitting information on a code inversion rule applied to the transmission signal together with the transmission signal.

According to an embodiment of the present invention, a reception apparatus modulates a received signal modulated by a Filter Bank Multicarrier (FBMC) / Quadrature Amplitude Modulation (OQAM) scheme by applying a code reversal rule to discrete fourier transform (DFT) spread data symbols. A demodulator for demodulating in the FBMC / OQAM scheme; a sign inverter for performing sign inversion on data symbols obtained by the demodulation according to sign inversion rule information for the sign inversion rule received together with the received signal; And an IDFT unit configured to generate estimated data symbols by performing an N (where N is the number of subcarriers) -point Inverse Discrete Fourier Transform (IDFT) on the data symbols on which sign inversion is performed.

The sign inversion unit may invert the sign of the real part or the imaginary part of the data symbols transmitted by the odd subcarriers among the data symbols obtained by the demodulation according to the received sign inversion rule information.

The sign inversion unit may invert the sign of the real part or the imaginary part of the data symbols transmitted by the even subcarrier among the data symbols obtained by the demodulation according to the received sign inversion rule information.

A reception method according to an embodiment of the present invention includes a received signal modulated by a Filter Bank Multicarrier (FBMC) / Quadrature Amplitude Modulation (OQAM) scheme by applying a code reversal rule to discrete Fourier Transform (DFT) spread data symbols; Receiving sign inversion rule information for the sign inversion rule, demodulating the received signal by the FBMC / OQAM scheme, and performing sign inversion on data symbols obtained by the demodulation according to the sign inversion rule information And performing an N (where N is the number of subcarriers) -point Inverse Discrete Fourier Transform (IDFT) on the data symbols on which the sign reversal has been performed to generate estimated data symbols.

In the performing of the sign inversion, the sign of the real part or the imaginary part of the data symbols transmitted by the odd subcarriers among the data symbols obtained by the demodulation may be inverted according to the received sign inversion rule information.

The performing of the sign inversion may invert the sign of the real part or the imaginary part of the data symbols transmitted by the even subcarriers among the data symbols obtained by the demodulation according to the received sign inversion rule information.

According to an embodiment of the present invention, a reception apparatus modulates a received signal modulated by a Filter Bank Multicarrier (FBMC) / Quadrature Amplitude Modulation (OQAM) scheme by applying a code reversal rule to discrete fourier transform (DFT) spread data symbols. A demodulator for demodulating according to the FBMC / OQAM scheme, a sign inversion unit for performing sign inversion on the data symbols obtained by the demodulation, and N for the data symbols on which sign inversion is performed (where N is the number of subcarriers) At least a part of an IDFT unit performing a point inverse discrete fourier transform (IDFT) to generate estimated data symbols, and at least some of the data symbols of one frame obtained by the demodulation according to the first sign inversion rule and the second sign inversion rule. The code inversion unit is controlled to perform sign inversion with respect to the IDFT unit from the data symbols on which sign inversion is performed according to the first sign inversion rule. The first code inversion rule and the second estimated data symbols generated by the IDFT unit from the first estimated data symbols generated and the data symbols in which sign inversion is performed according to the second code inversion rule; An estimation for estimating one of the second sign inversion rules as a sign inversion rule applied to the received signal and controlling the sign inversion unit to perform sign inversion on the data symbols of the one frame according to the estimated sign inversion rule Contains wealth.

The estimator is configured to apply one of the first code inversion rule and the second code inversion rule to the received signal based on the discriminating coordinates of the real part and the imaginary part of the first estimated data symbols and the second estimated data symbols. It can be estimated by the sign inversion rule.

The estimator compares the variance of the real part and the imaginary part of the first estimated data symbols with the variance of the real part and the imaginary part of the second estimated data symbols according to the discriminating coordinates, thereby determining the first sign inversion rule and One of the second sign inversion rules may be estimated as a sign inversion rule applied to the received signal.

The first code inversion rule inverts the sign of an imaginary part of data symbols transmitted by an odd-numbered subcarrier among the data symbols obtained by the demodulation, and the second code inversion rule is data obtained by the demodulation. The symbols of the real part of the data symbols transmitted by the odd subcarriers among the symbols may be inverted.

The first sign inversion rule inverts the sign of an imaginary part of data symbols transmitted by an even-numbered subcarrier among the data symbols obtained by the demodulation, and the second sign inversion rule is data obtained by the demodulation. The symbols of the real part of the data symbols transmitted by the even subcarrier among the symbols may be inverted.

According to an embodiment of the present invention, a reception method modulated by a Filter Bank Multicarrier (FBMC) / Quadrature Amplitude Modulation (OQAM) scheme is applied by applying a code inversion rule to discrete Fourier Transform (DFT) spread data symbols. Receiving, demodulating the received signal in the FBMC / OQAM scheme, performing sign inversion according to a first sign inversion rule on at least some of the data symbols of one frame obtained by the demodulation, Generating first estimated data symbols by performing an N (where N is the number of subcarriers) -point Inverse Discrete Fourier Transform (IDFT) on the data inverted symbols according to a first sign inversion rule, by demodulation Performing sign inversion according to a second sign inversion rule on at least some of the obtained data symbols in one frame, in accordance with the second sign inversion rule Generating second estimated data symbols by performing an N-point IDFT on the sign inverted data symbols, using the first estimated data symbols and the second estimated data symbols, the first sign inversion rule and the Estimating one of a second sign inversion rule with a sign inversion rule applied to the received signal, performing sign inversion on the data symbols of the one frame according to the estimated sign inversion rule, and the estimated sign inversion Generating an estimated data symbol by performing an N-point IDFT on data symbols on which sign inversion is performed according to a rule.

The estimating may include receiving one of the first sign inversion rule and the second sign inversion rule based on the discriminating coordinates of the real part and the imaginary part of the first estimated data symbols and the second estimated data symbols. It can be estimated by the sign inversion rule applied to.

The estimating may include comparing a variance of the first estimated data symbols with the real part and the imaginary part and the variance of the second estimated data symbols with the real part and the imaginary part, thereby inverting the first sign. One of a rule and the second sign inversion rule may be estimated as a sign inversion rule applied to the received signal.

According to the embodiments of the present invention, the FBMC / OQAM modulation is performed by inverting the code according to a specific rule in the FBMC / OQAM scheme using DFT spreading to perform FBMC / OQAM modulation. It can effectively improve peak-to-average power ratio (PAPR) performance while retaining the benefits.

Furthermore, according to embodiments of the present invention, in order to improve the peak-to-average power ratio (PAPR) performance, in the structure of the FBMC / OQAM scheme using the conventional DFT spreading, a configuration for inverting the code according to a specific rule is performed. Since only added, it has a similar or lower complexity compared to the peak-to-average power ratio (PAPR) performance improvement scheme of the conventional FBMC technique.

1 is a diagram illustrating an equivalent equation structure for a transmitting end of a conventional FBMC / OQAM (Filter Bank Multi-Carrier / Offset Quadrature Amplitude Modulation) technique.

FIG. 2 is a diagram illustrating an equivalent equation structure for a transmitter of a conventional DFT spreading FBMC / OQAM scheme in which a Discrete Fourier Transform (DFT) spreading process is added.

FIG. 3 is a diagram illustrating an implementation structure in which the equation structure shown in FIG. 2 is modified into a structure that can be actually implemented.

4 shows an equivalent mathematical structure for the implementation structure shown in FIG.

5 is a block diagram of an apparatus for transmitting a filter bank multicarrier system according to an exemplary embodiment of the present invention.

FIG. 6 is a diagram illustrating an equivalent equation structure of a sign inverting unit 520 and a modulator 530 for generating a first transmission signal candidate according to an embodiment of the present invention.

FIG. 7 illustrates an actual implementation structure for the equivalent mathematical structure shown in FIG. 6. FIG.

8 is a diagram illustrating an equivalent equation structure of the sign inverting unit 520 and the modulator 530 for generating a second transmission signal candidate according to an embodiment of the present invention.

FIG. 9 illustrates an actual implementation structure of the equivalent mathematical structure shown in FIG. 8. FIG.

10 shows an overall implementation structure of an apparatus according to an embodiment of the present invention.

11 illustrates an overall implementation structure of an apparatus according to another embodiment of the present invention.

12 is a diagram illustrating an equivalent equation structure for a receiver of a conventional FBMC / OQAM scheme.

FIG. 13 is a diagram illustrating an actual implementation structure of a receiver of the conventional FBMC / OQAM scheme illustrated in FIG. 12.

14 is a block diagram of a receiving apparatus according to an embodiment of the present invention;

FIG. 15 is a diagram illustrating an actual implementation structure of the reception device illustrated in FIG. 14.

16 is a block diagram of a receiving apparatus according to another embodiment of the present invention.

FIG. 17 is a diagram illustrating an actual implementation structure of the reception device illustrated in FIG. 16.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The following detailed description is provided to assist in a comprehensive understanding of the methods, devices, and / or systems described herein. However, this is only an example and the present invention is not limited thereto.

In describing the embodiments of 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 thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or an operator. Therefore, the definition should be made based on the contents throughout the specification. The terminology used in the description is for the purpose of describing embodiments of the invention only and should not be limiting. Unless expressly used otherwise, the singular forms “a,” “an,” and “the” include plural forms of meaning. In this description, expressions such as "comprises" or "equipment" are intended to indicate certain features, numbers, steps, actions, elements, portions or combinations thereof, and one or more than those described. It should not be construed to exclude the presence or possibility of other features, numbers, steps, actions, elements, portions or combinations thereof.

Mth data symbol transmitted by nth subcarrier in FBMC / OQAM scheme

May be represented by Equation 1 below.

[Equation 1]

At this time,

Wow

Are symbols of the real part and the imaginary part of the mth data symbol transmitted by the nth subcarrier, respectively, N is the number of subcarriers allocated to each user, and M is the length of the frame. Hereinafter, m, n, N, and M are interpreted by the same meaning.

Referring to FIG. 1, in the conventional FBMC / OQAM scheme, first, parallel data symbols are divided into a real part and an imaginary part and input in units of T seconds (110). Where T is each parallel data symbol

Represents a symbol section.

Subsequently, the real part of the data symbol to be transmitted by the nth subcarrier is input to the prototype filter h (t) as it is, and the imaginary part is multiplied by the imaginary j and then the prototype filter h (tT / 2) delayed by T / 2 on the time axis Enter (120). At this time, the impulse response length of the prototype filter is determined by the superposition coefficient of the filter.

Then, after adding the outputs of h (t) and h (tT / 2), the nth subcarrier is

Multiply by 130.

Then, the transmission signal by adding all the signals multiplied by the subcarrier

Generate (140). At this time, the transmission signal

Equation is as shown in Equation 2 below.

[Equation 2]

Meanwhile, the conventional FBMC / OQAM scheme shown in FIG. 1 has a high peak to average power ratio (PAPR) due to multi-carrier modulation.

FIG. 2 is a diagram illustrating an equivalent equation structure for a transmitter of a conventional DFT spreading FBMC / OQAM scheme to which a Discrete Fourier Transform (DFT) spreading process is added.

Referring to FIG. 2, the conventional DFT spreading FBMC / OQAM scheme performs a process of performing DFT spreading on parallel data symbols in the transmit structure of the FBMC / OQAM scheme of FIG. 1 to reduce the peak-to-average power ratio (PAPR). ) Is preceded.

At this time, the matrix of parallel data symbols

When DFT is spread, DFT spread data symbols

It can be represented as

Also,

Is the nth element of

May be expressed as Equation 3 below.

[Equation 3]

At this time,

silver

The real part of,

silver

The imaginary part of is shown and is interpreted with the same meaning below.

Meanwhile, the structure after the DFT spreading process 210 in the transmitting end structure of the conventional DFT spreading FBMC / OQAM scheme shown in FIG. 2 is the same as the transmitting end structure of the conventional FBMC / OQAM technique shown in FIG.

Meanwhile, the transmission signal equation of the conventional DFT spreading FBMC / OQAM scheme shown in FIG. 2 is expressed by Equation 4 below.

[Equation 4]

In the case of the conventional DFT spreading FBMC / OQAM scheme shown in FIG. 2, a peak-to-average power ratio (PAPR) mitigation effect can be obtained. However, the transmit end structure shown in FIG. Since it is a mathematical structure, it is not suitable for practical implementation.

Specifically, FIG. 3 is a diagram illustrating an implementation structure in which the equation structure shown in FIG. 2 is modified to a structure that can be actually implemented.

The equation of the transmission signal generated by the implementation structure shown in FIG. 3 is shown in Equation 5 below.

[Equation 5]

The implementation structure shown in FIG. 3 is represented by an equivalent mathematical structure for the transmission signal of Equation 5 as shown in FIG. 4.

Referring to FIG. 4, an equivalent equation structure for a transmission signal of Equation 5 may be compared to an imaginary part of data symbols to be transmitted by each subcarrier, compared to the equation structure shown in FIG. 2.

It can be seen that the phase component of is multiplied (410), which causes a reduction in the peak-to-average power ratio (PAPR) reduction effect due to DFT spreading.

Referring to FIG. 5, a transmission apparatus 500 according to an embodiment of the present invention includes a DFT unit 510, a code inversion unit 520, a modulator 530, and a selector 540.

The DFT unit 510 performs N-point DFT on the parallel data symbols to generate DFT spread data symbols.

The sign inversion unit 520 generates first data symbols by applying a first sign inversion rule to the data symbols DFT-spread by the DFT unit 510, and generates a first sign inversion rule in the DFT spread data symbols. Different second sign inversion rules are applied to generate second data symbols.

Specifically, according to an embodiment of the present invention, the sign inverting unit 520 generates the first data symbols by inverting the sign of the imaginary part of the data symbols to be transmitted by the odd subcarriers of the DFT spread data symbols, Second data symbols may be generated by reversing the sign of the real part of the data symbols to be transmitted by the odd subcarriers among the spread data symbols.

The modulator 530 modulates each of the first data symbols and the second data symbols on which the sign inversion is performed by the sign inverting unit 520 in the FBMC / OQAM scheme, thereby the first transmission candidate signal and the second transmission candidate signal. Create

The selector 540 measures the peak or peak-to-average power ratio (PAPR) for each of the first transmission candidate signal and the second transmission candidate signal generated by the modulation unit 530, and selects the first transmission candidate signal and the first transmission candidate signal. 2 Among the transmission candidate signals, a signal having a small peak value or peak-to-average power ratio (PAPR) is selected and transmitted as a transmission signal.

In this case, according to an embodiment of the present invention, the selector 540 may transmit information on the code inversion rule applied to the transmission signal together with the transmission signal.

FIG. 6 is a diagram illustrating an equivalent equation structure of the sign inverting unit 520 and the modulator 530 for generating a first transmission signal candidate according to an embodiment of the present invention.

Referring to FIG. 6, the sign inversion unit 520 extracts an imaginary part and a real part for each of the DFT spread data symbols generated by the DFT unit 510 and extracts the imaginary part from the imaginary part.

The phase component of can be multiplied by

Accordingly, the imaginary part of the data symbols to be transmitted by each subcarrier

Phase component of

The phase component of is multiplied by

Is multiplied by an imaginary number in the conventional FBMC / OQAM implementation.

The phase component of can be canceled out.

Accordingly, since the real part and the imaginary part of the data symbols to be transmitted by each subcarrier have the same phase, a peak-to-average power ratio (PAPR) reduction effect due to DFT spreading can be obtained.

Meanwhile, the first transmission signal candidate generated by the modulator 530 according to the example shown in FIG. 6.

The equation of is as shown in Equation 6 below.

[Equation 6]

Meanwhile, the actual implementation structure of the equivalent mathematical structure shown in FIG. 6 is the same as the example shown in FIG. 7.

Specifically, referring to FIG. 7, the actual implementation of the equivalent equation structure of the sign inverting unit 520 illustrated in FIG. 6 is transmitted by an odd subcarrier among the data symbols spread by the DFT unit 510. Inverting the imaginary code of the data symbols to be implemented may be implemented, and the modulation unit 530 may have the same structure as that of the conventional FBMC / OQAM modulation scheme.

8 illustrates an equivalent mathematical structure of the sign inverting unit 520 and the modulator 530 for generating a second transmission signal candidate according to an embodiment of the present invention.

Referring to FIG. 8, the sign inversion unit 520 extracts an imaginary part and a real part from each of the DFT spread data symbols generated by the DFT part 510.

The phase component of can be multiplied by

Accordingly, the real part and the imaginary part of data symbols to be transmitted by each subcarrier

Since the same phase components are multiplied so that the phase difference between the real part and the imaginary part is the same, the peak-to-average power ratio (PAPR) can be reduced.

Meanwhile, the second transmission signal candidate generated by the modulator 530 according to the example shown in FIG. 8

Equation 7 is as shown in Equation 7 below.

[Equation 7]

Meanwhile, the actual implementation structure of the equivalent mathematical structure shown in FIG. 8 is the same as the example shown in FIG. 9.

Specifically, referring to FIG. 9, the actual implementation of the equivalent mathematical structure of the sign inverting unit 520 illustrated in FIG. 8 is transmitted by an odd subcarrier among the data symbols spread by the DFT unit 510. Inverting the real part code of the data symbols to be implemented may be implemented, and the modulator 530 may have the same structure as that of the conventional FBMC / OQAM modulation scheme.

10 is a diagram showing the overall implementation structure of the transmitting apparatus 500 according to an embodiment of the present invention.

In the example shown in FIG. 10, i denotes a sign inversion rule applied to the DFT spread data symbols, and is interpreted in the same sense hereinafter.

Referring to FIG. 10, the sign inversion unit 520 inverts the sign of an imaginary part of data symbols to be transmitted by an odd-numbered subcarrier among the data symbols DFT spread by the DFT unit 510 (that is, i = 0). The first data symbols are generated, and the modulator 530 modulates the first data symbols in an FBMC / OQAM scheme to thereby generate a first transmission signal candidate.

Create

In addition, the sign inverting unit 520 inverts the sign of the real part of the data symbols to be transmitted by the odd-numbered subcarriers among the data symbols spread by the DFT unit 510 (that is, i = 1). And the modulator 530 modulates the second data symbols in an FBMC / OQAM scheme to generate a second transmission signal candidate.

Create

Thereafter, the selector 540 selects the first transmission signal candidate.

And second transmission signal candidate

Determine the peak or peak-to-average power ratio (PAPR) for each of the transmitted signal candidates with the smallest peak or peak-to-average power ratio (PAPR).

To select.

At this time,

For example, the peak of can be measured according to Equation 8 below,

The peak of can also be measured in the same way.

[Equation 8]

In this case, K represents the impulse response length of the prototype filter h (t), it is interpreted as the same meaning below.

Also,

The peak-to-average power ratio of PAPR may be measured according to Equation 9 below,

The peak-to-average power ratio of PAPA can also be measured in the same way.

[Equation 9]

Meanwhile, according to an embodiment, the selector 540 selects the selected transmission signal.

Transmits information about the sign inversion rule applied to the signal (i.e. i = 0 or i = 1)

Can be sent with.

In addition, in the above-described embodiments, sign inversion is performed on data symbols to be transmitted by odd-numbered subcarriers among the DFT spread data symbols, but is not limited thereto.

For example, unlike the above-described embodiments, even when the sign inversion rule is applied to the data symbols to be transmitted by the even-numbered subcarriers among the DFT spread data symbols as in the example shown in FIG. Average power ratio (PAPR) performance can be achieved.

Specifically, referring to FIG. 11, the sign inverting unit 520 inverts the sign of the imaginary part of the data symbols to be transmitted by the even-numbered subcarriers among the data symbols DFT spread by the DFT unit 510 (that is, i = 0) generating first data symbols, and the modulator 530 modulates the first data symbols in an FBMC / OQAM scheme to form a first transmission signal candidate

Create

In addition, the sign inverting unit 520 inverts the sign of the real part of the data symbols to be transmitted by the even-numbered subcarriers among the data symbols spread by the DFT unit 510 (that is, i = 1). And the modulator 530 modulates the second data symbols in an FBMC / OQAM scheme to generate a second transmission signal candidate.

Create

Thereafter, the selector 540 selects the first transmission signal candidate.

And second transmission signal candidate

To select.

At this time, according to an embodiment, the selector 540 selects the selected transmission signal.

Can be sent with.

Referring to FIG. 12, a reception signal of a conventional FBMC / OQAM scheme first receives a signal.

After multiplying the subcarrier by 1210, h (t) and h (tT / 2) are input to the prototype filters h (t-mT) and h (tT / 2-mT), which are delayed by mT on the time axis (1220). ).

Then, the real and imaginary parts are extracted from the outputs of the prototype filters h (t-mT) and h (tT / 2-mT), and the mT and mT + T / 2 seconds signals where the m th data symbol is located are sampled. Estimated data symbol in

and

Obtain (1230).

Meanwhile, the actual implementation structure of the receiver of the conventional FBMC / OQAM scheme shown in FIG. 12 is shown in FIG.

14 is a block diagram of a receiving apparatus 1400 according to an embodiment of the present invention.

Referring to FIG. 14, in an embodiment of the present invention, the reception device 1400 includes a demodulator 1410, a sign inversion unit 1420, and a DFT unit 1430.

The demodulator 1410 demodulates the received signal by the FBMC / OQAM method. In this case, the received signal is a signal modulated and transmitted by the transmitting apparatus 500 shown in FIG. 5.

That is, the received signal may be a signal modulated in the FBMC / OQAM scheme by applying a specific code inversion rule to the DFT spread data symbols.

In this case, according to an embodiment of the present invention, the specific sign inversion rule may be sign inversion of an imaginary part or a real part of data symbols to be transmitted by an odd subcarrier among the DFT spread data symbols.

According to another embodiment of the present invention, the specific sign inversion rule may be a sign inversion of an imaginary part or a real part of data symbols to be transmitted by an even subcarrier among the DFT spread data symbols.

On the other hand, the received signal may include information (ie, i = 0 or i = 1) about the code inversion rule performed by the transmitting apparatus 500.

The sign inversion unit 1420 performs inversion of the data symbols demodulated by the demodulator 1410 according to the sign inversion rule information included in the received signal.

The IDFT unit 1430 generates estimated data symbols by performing an N-point Inverse Discrete Fourier Transform (IDFT) on the data symbols on which the sign inversion is performed by the sign inversion unit 1420.

In detail, FIG. 15 is a diagram illustrating an actual implementation structure of the receiving apparatus 1400 illustrated in FIG. 14.

Referring to FIG. 15, first, the demodulator 1410 receives a received signal in the same manner as the conventional FBMC / OQAM technique.

Demodulate.

Thereafter, the sign inversion unit 1420 extracts the real part and the imaginary part of each data symbol demodulated by the demodulation unit 1420 and performs sign inversion according to the sign inversion information i received together with the received signal.

In this case, according to an embodiment of the present invention, when the i value is 0, the sign inversion unit 1420 may include an imaginary part of the data symbols transmitted by the odd subcarriers among the data symbols demodulated by the demodulator 1420. When the sign is inverted and the value of i is 1, the sign of the real part of the data symbols transmitted by the odd subcarriers among the data symbols demodulated by the demodulator 1420 may be inverted.

Meanwhile, according to another embodiment of the present invention, unlike the example shown in FIG. 14, the sign inversion unit 1420 has an even subcarrier among the data symbols demodulated by the demodulator 1420 when the i value is 0. Inverts the sign of the imaginary part of the data symbols transmitted by the symbol, and if the value of i is 1, inverts the sign of the real part of the data symbols transmitted by the even subcarriers of the data symbols demodulated by the demodulator 1420. Can be.

Thereafter, the IDFT unit 1430 multiplies the imaginary part of each data symbol output by the sign inverting unit 1420 by an imaginary number j, adds the real part, and then performs an N-point IDFT to estimate the data symbol.

Can be obtained.

Specifically, the estimated data symbol is

Can be expressed as

and

Denotes estimated data symbols of the real part and the imaginary part, respectively.

Referring to FIG. 16, a receiver 1600 according to an exemplary embodiment of the present invention includes a demodulator 1610, a code inverter 1620, an IDFT unit 1630, and an estimator 1640.

In the example illustrated in FIG. 16, since the demodulator 1610 has the same configuration as that illustrated in FIG. 14, redundant description thereof will be omitted.

The sign inversion unit 1620 performs sign inversion on at least some of the data symbols of one frame demodulated by the demodulator 1610 under the control of the estimator 1640.

The IDFT unit 1630 performs N-point IDFT on the data symbols outputted by the sign inversion unit 1620 and outputs the estimated data symbols.

The estimator 1640 estimates the sign inversion rule (i) applied to the received signal and controls the sign inversion performed by the sign inversion unit 1620 according to the estimated sign inversion rule.

In detail, FIG. 17 is a diagram illustrating an actual implementation structure of the reception apparatus 1600 illustrated in FIG. 16.

Referring to FIG. 17, the estimator 1640 first sets i = 0 to control sign inversion of an imaginary part of data symbols transmitted by an odd subcarrier by the sign inversion unit 1620. In this case, sign inversion may be performed on at least some of the data symbols of one frame demodulated by the demodulator 1610.

Thereafter, the IDFT unit 1630 generates the first estimated data symbol by performing IDFT on the data symbols on which the sign inversion is performed by the sign inversion unit 1620.

In this case, the estimated data symbols of the real part and the imaginary part of the first estimated data symbol acquired by the IDFT unit 1630 are respectively obtained.

Wow

In this case, the estimation unit 1640 according to a quadrature amplitude modulation (QAM) scheme.

Wow

Can be classified into each discriminating coordinate. In addition, the estimator 1640 is classified based on each of the discriminating coordinates using, for example, Equation 10 below.

Wow

Dispersion

Can be obtained.

[Equation 10]

At this time,

silver

Represents the discriminating coordinate of,

silver

Indicates the discriminating coordinate of.

Subsequently, the estimator 1640 sets i = 1 to control the sign inversion of the real part of the data symbols transmitted by the odd subcarrier by the sign inverter 1620. In this case, sign inversion may be performed on at least some of the data symbols of one frame demodulated by the demodulator 1610.

Thereafter, the IDFT unit 1630 generates the second estimated data symbol by performing IDFT on the data symbols on which the sign inversion is performed by the sign inversion unit 1620.

In this case, the estimated data symbols of the real part and the imaginary part of the second estimated data symbol acquired by the IDFT unit 1630 are respectively obtained.

Wow

In this case, the estimation unit 1640 according to the QAM method.

Wow

Are classified into respective discriminating coordinates, and classified according to each discriminating coordinate using Equation 11 below.

Wow

Dispersion

Can be obtained.

[Equation 11]

At this time,

silver

Represents the discriminating coordinate of

silver

Indicates the discriminating coordinate of.

Thereafter, the estimator 1640

and

By comparing the Equation 12, the sign reversal rule can be estimated.

[Equation 12]

At this time,

Denotes an estimated sign reversal rule.

Thereafter, the estimator 1640

The sign inversion unit 1620 controls the sign inversion of data symbols of one frame according to the value, and the IDFT unit 1630

According to a value, an N-point IDFT may be performed on data symbols on which sign inversion is performed, thereby finally generating estimated data symbols.

Meanwhile, in the embodiment shown in Fig. 17, the i value and

Although it has been described that the sign of the imaginary part and the real part of the data symbols transmitted by the odd subcarriers according to the value is not necessarily limited thereto, unlike the example shown in FIG. 17, the sign inverting unit 1620 has an i value. And

According to the value, it is possible to invert the imaginary part and the real part of the data symbols transmitted by the even subcarriers.

Meanwhile, an embodiment of the present invention may include a computer readable recording medium including a program for performing the methods described herein on a computer. The computer-readable recording medium may include program instructions, local data files, local data structures, etc. alone or in combination. The media may be those specially designed and constructed for the purposes of the present invention, or those conventionally available in the field of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical recording media such as CD-ROMs, DVDs, magnetic-optical media such as floppy disks, and ROM, RAM, flash memory, and the like. Hardware devices specifically configured to store and execute program instructions are included. Examples of program instructions may include high-level language code that can be executed by a computer using an interpreter as well as machine code such as produced by a compiler.

While the exemplary embodiments of the present invention have been described in detail above, those skilled in the art will appreciate that various modifications can be made to the above-described embodiments without departing from the scope of the present invention. . Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

[Description of the code]

500: receiving device

510: DFT unit

520: code inversion

530: modulator

540: selection

1400, 1600: receiver

1410, 4610: demodulator

1420, 1620: code inversion

1430, 1630: IDFT Department

1640: estimator

Claims

A DFT unit for performing N (where N is the number of subcarriers) -point Discrete Fourier Transform (DFT) on the parallel data symbols to generate DFT spread data symbols;

Applying a first sign inversion rule to the DFT spread data symbols to generate first data symbols, and applying a second sign inversion rule different from the first sign inversion rule to the DFT spread data symbols to generate a second data symbol. A sign inversion unit for generating data symbols;

A modulator configured to modulate each of the first data symbol and the second data symbol by a FBMC / Quadrature Amplitude Modulation (OQAM) scheme to generate a first transmission candidate signal and a second transmission candidate signal; And

A peak or peak to average power ratio (PAPR) for the first transmission candidate signal and the second transmission candidate signal is measured, and among the first transmission candidate signal and the second transmission candidate signal And a selection unit for selecting and transmitting a signal having a small peak or average peak to average power ratio (PAPR) as a transmission signal.
The method according to claim 1,

The code inverting unit inverts the imaginary part codes of data symbols to be transmitted by odd-numbered subcarriers of the DFT spread data symbols to generate the first data symbols, and real numbers of data symbols to be transmitted by odd-numbered subcarriers. And transmitting the second sign to generate the second data symbols.
The method according to claim 1,

The code inverting unit inverts the imaginary code of the data symbols to be transmitted by the even-numbered subcarriers of the DFT spread data symbols to generate the first data symbols, and real numbers of the data symbols to be transmitted by the even-numbered subcarrier. And transmitting the second sign to generate the second data symbols.
The method according to claim 1,

And the selecting unit transmits information on a code inversion rule applied to the transmission signal together with the transmission signal.
Performing N (where N is the number of subcarriers) -point Discrete Fourier Transform (DFT) on the parallel data symbols to generate DFT spread data symbols;

Generating first data symbols by applying a first sign inversion rule to the DFT spread data symbols;

Generating a first transmission candidate signal by modulating the first data symbol by a FBMC / Quadrature Amplitude Modulation (OQAM) scheme;

Generating second data symbols by applying a second sign inversion rule different from the first sign inversion rule to the DFT spread data symbols;

Modulating the second data symbol in an FBMC / OQAM scheme to generate a second transmission candidate signal;

Measuring a peak or peak to average power ratio (PAPR) for the first transmission candidate signal and the second transmission candidate signal; And

And selecting and transmitting, as a transmission signal, a signal having the smallest peak or peak to average power ratio (PAPR) among the first transmission candidate signal and the second transmission candidate signal.
The method according to claim 5,

The generating of the first data symbols may include generating the first data symbols by inverting an imaginary code of data symbols to be transmitted by an odd-numbered subcarrier among the DFT spread data symbols,

The generating of the second data symbols may include generating the second data symbols by inverting the real part code of the data symbols to be transmitted by the odd subcarrier.
The method according to claim 5,

The generating of the first data symbols may include generating the first data symbols by inverting an imaginary code of data symbols to be transmitted by an even subcarrier among the DFT spread data symbols,

The generating of the second data symbols may include generating the second data symbols by inverting a real part code of data symbols to be transmitted by the even subcarrier.
The method according to claim 5,

The transmitting may include transmitting information on a code inversion rule applied to the transmission signal together with the transmission signal.
A demodulator for demodulating a received signal modulated by a Filter Bank Multicarrier (FBMC) / Quadrature Amplitude Modulation (OQAM) scheme using the FBMC / OQAM scheme by applying a code reversal rule to DFT (Discrete Fourier Transform) spread data symbols;

A sign inversion unit which performs sign inversion on the data symbols obtained by the demodulation according to the sign inversion rule information received together with the received signal; And

And an IDFT unit configured to generate estimated data symbols by performing an N (where N is the number of subcarriers) -point Inverse Discrete Fourier Transform (IDFT) on the data symbols on which the sign inversion is performed.
The method according to claim 9,

And the sign inverting unit inverts the sign of the real part or the imaginary part of the data symbols transmitted by the odd subcarrier among the data symbols obtained by the demodulation according to the received sign inversion rule information.
The method according to claim 9,

And the sign inversion unit inverts the sign of the real part or the imaginary part of the data symbols transmitted by the even subcarrier among the data symbols obtained by the demodulation according to the received sign inversion rule information.
Applying a code inversion rule to the Discrete Fourier Transform (DFT) spread data symbols to receive received signal and code inversion rule information modulated in a Filter Bank Multicarrier (FBMC) / Quadrature Amplitude Modulation (OQAM) scheme;

Demodulating the received signal in the FBMC / OQAM scheme;

Performing sign inversion on data symbols obtained by the demodulation according to the sign inversion rule information; And

And performing an N (where N is the number of subcarriers) -point Inverse Discrete Fourier Transform (IDFT) on the data symbols on which the sign reversal has been performed to generate estimated data symbols.
The method according to claim 12,

The performing of the sign inversion may include inverting the sign of a real part or an imaginary part of data symbols transmitted by an odd subcarrier among data symbols obtained by the demodulation according to the received sign inversion rule information.
The method according to claim 12,

The performing of the sign inversion may include inverting the sign of a real part or an imaginary part of data symbols transmitted by an even subcarrier among data symbols obtained by the demodulation according to the received sign inversion rule information.
A demodulator for demodulating a received signal modulated by a Filter Bank Multicarrier (FBMC) / Quadrature Amplitude Modulation (OQAM) scheme using the FBMC / OQAM scheme by applying a code reversal rule to DFT (Discrete Fourier Transform) spread data symbols;

A sign inversion unit which performs sign inversion on the data symbols obtained by the demodulation;

An IDFT unit configured to generate estimated data symbols by performing an N-point Inverse Discrete Fourier Transform (IDFT) -point IDFT on the data symbols on which sign inversion is performed;

Control the sign inversion unit so that sign inversion is performed on at least some of the data symbols of one frame obtained by the demodulation according to the first sign inversion rule and the second sign inversion rule, and in accordance with the first sign inversion rule. First estimation data symbols generated by the IDFT unit from data symbols on which sign inversion is performed and second estimation generated by the IDFT unit from data symbols on which sign inversion is performed according to the second sign inversion rule. Using data symbols, one of the first sign inversion rule and the second sign inversion rule is estimated as a sign inversion rule applied to the received signal, and is applied to the data symbols of the one frame according to the estimated sign inversion rule. And an estimator for controlling the sign inversion unit so that sign inversion is performed.
The method according to claim 15,

The estimator is configured to apply one of the first code inversion rule and the second code inversion rule to the received signal based on the discriminating coordinates of the real part and the imaginary part of the first estimated data symbols and the second estimated data symbols. Receiving device inferring with sign inversion rule.
The method according to claim 16,

The estimator compares the variance of the real part and the imaginary part of the first estimated data symbols with the variance of the real part and the imaginary part of the second estimated data symbols according to the discriminating coordinates, thereby determining the first sign inversion rule and And a receiver for estimating one of the second sign inversion rules as a sign inversion rule applied to the received signal.
The method according to claim 15,

The first sign inversion rule inverts the sign of an imaginary part of data symbols transmitted by an odd-numbered subcarrier among data symbols obtained by the demodulation,

And the second sign inversion rule inverts the sign of the real part of the data symbols transmitted by an odd subcarrier among the data symbols obtained by the demodulation.
The method according to claim 15,

The first sign inversion rule inverts the sign of an imaginary part of data symbols transmitted by an even subcarrier among data symbols obtained by the demodulation,

And the second sign inversion rule inverts the sign of the real part of the data symbols transmitted by the even subcarrier among the data symbols obtained by the demodulation.
Receiving a received signal modulated by a Filter Bank Multicarrier (FBMC) / Quadrature Amplitude Modulation (OQAM) scheme by applying a sign reversal rule to the Discrete Fourier Transform (DFT) spread data symbols;

Demodulating the received signal in the FBMC / OQAM scheme;

Performing sign inversion according to a first sign inversion rule on at least some of the data symbols of one frame obtained by the demodulation;

Generating first estimated data symbols by performing an N (where N is the number of subcarriers) -point Inverse Discrete Fourier Transform (IDFT) on the data inverted symbols according to the first sign inversion rule;

Performing sign inversion according to a second sign inversion rule on at least some of the data symbols of one frame obtained by the demodulation;

Generating second estimated data symbols by performing an N-point IDFT on the sign inverted data symbols according to the second sign inversion rule;

Estimating, using the first estimated data symbols and the second estimated data symbols, one of the first sign inversion rule and the second sign inversion rule as a sign inversion rule applied to the received signal;

Performing sign inversion on the data symbols of the one frame according to the estimated sign inversion rule; And

And generating an estimated data symbol by performing an N-point IDFT on data symbols on which sign inversion is performed according to the estimated sign inversion rule.
The method of claim 20,

The estimating may include receiving one of the first sign inversion rule and the second sign inversion rule based on the discriminating coordinates of the real part and the imaginary part of the first estimated data symbols and the second estimated data symbols. Receiving method estimated by code inversion rule applied to.
The method according to claim 21,

The estimating may include comparing a variance of the first estimated data symbols with the real part and the imaginary part and the variance of the second estimated data symbols with the real part and the imaginary part, thereby inverting the first sign. And a method of estimating one of a rule and the second sign inversion rule as a sign inversion rule applied to the received signal.
The method of claim 20,

The first sign inversion rule inverts the sign of an imaginary part of data symbols transmitted by an odd-numbered subcarrier among data symbols obtained by the demodulation,

And the second sign inversion rule inverts the sign of a real part of data symbols transmitted by an odd subcarrier among data symbols obtained by the demodulation.
The method of claim 20,

The first sign inversion rule inverts the sign of an imaginary part of data symbols transmitted by an even subcarrier among data symbols obtained by the demodulation,

And the second sign inversion rule inverts the sign of a real part of data symbols transmitted by an even subcarrier among the data symbols obtained by the demodulation.