KR20200088036A - Apparatus and method for PAPR reduction in polar-coded OFDM communication systems - Google Patents

Abstract

A transmitting apparatus of an orthogonal frequency division multiplexing (OFDM) communication system to which a polar code is applied and a method of reducing a peak-to-average power ratio (PAPR) of the same are provided. According to the present invention, the method of reducing a PAPR of the OFDM communication system to which a polar code is applied comprises the steps of: defining a set of a plurality of different frozen data blocks; generating a plurality of OFDM signals including the same information for each set of the plurality of different frozen data blocks but having different types; and selecting a signal having the minimum PAPR for the plurality of OFDM signals having different types and transmitting the signal using selective mapping (SLM).

Description

Apparatus and method for PAPR reduction in polar-coded OFDM communication systems

The present invention relates to a transmission apparatus of an OFDM communication system to which a polar code is applied and a PAPR reduction method thereof.

Orthogonal frequency division multiplexing (OFDM) is a technique for waveforms that has been traditionally applied to various wireless/mobile communication systems. CP-OFDM is also adopted/applied in recent 5G NR standards. Here, a high peak-to-average power ratio (PAPR) characteristic is a major drawback and problem.

Techniques for reducing PAPR due to the nonlinear nature of low cost power amplifiers are important. Considering a low cost terminal in a 5G mMTC scenario, for example, a low cost terminal in a low-power wide area (LPWA) application and a low cost power amplifier mounted in a small base station can be used.

As a technique for reducing PAPR in an OFDM system, there is a selective mapping technique. The selective mapping technique transmits a signal having the minimum PAPR after generating multiple signals of the same type but with the same information. The main feature is that the transmission rate decreases when additional information is transmitted about which signal is transmitted, and the transmission rate decreases when the additional information is not transmitted can be prevented. Deterioration may occur. In addition, it consumes high-complexity computation compared to the transmitting and receiving end of a typical OFDM system. Existing selective mapping techniques using channel codes have been proposed, but there is no technology regarding techniques using polar codes determined as a standard for a control channel of the recent 5G NR eMBB standard.

1 is a view showing a structure of a transmitter of an OFDM system to which a polar code is applied according to the prior art.

The transmitting end of the OFDM system to which the polar code according to the prior art is applied includes a CRC encoder 110, a frozen bit inserter 120, a polar encoder 130, a modulator 140, and an IDFT 150.

인 이진 데이터 블록(

)을 나타내었다. 부호화 과정은 다음과 같다. Referring to Figure 1, the length

In binary data block (

). The encoding process is as follows.

CRC 부호화기(110)는

개의 CRC 비트를 생성 후 이진 데이터 블록에 첨가함으로써 비동결 데이터 블록

를 생성한다. 여기서, A는 비동결 데이터 전송을 위한 부채널의 인덱스 집합이고, A^c는 동결 데이터 전송을 위한 부채널의 인덱스 집합이다.

CRC encoder 110 is

Non-freezing data block by generating CRC bits and adding them to the binary data block

Produces Here, A is an index set of subchannels for non-freezing data transmission, and A ^c is an index set of subchannels for freezing data transmission.

(120)을 삽입함으로써 폴라 부호화기의 입력 블록

를 생성한다. Freeze data block

Input block of polar encoder by inserting 120

Produces

폴라 부호화기(130)는 폴라 부호의 블록 길이가

이고, 채널 분극 현상을 발생시키는 분극 행렬은

로 나타낼 수 있고, 여기서 Arikan의 커널 행렬은

이다.

The polar encoder 130 has a block length of the polar code.

And the polarization matrix that causes the channel polarization

Can be represented as, where Arikan's kernel matrix is

to be.

는 행렬

에 대하여 Kronecker power 연산을

번 수행함을 의미한다. 인덱스 집합 A와 A^c에 대하여 인덱스에 대응되는 행으로 구성된 부분 행렬을 각각

와

로써 표기한다. 폴라 부호화를 통하여 부호어

를 생성할 수 있다. 이때, 적용된 채널 부호의 부호율은

이 된다. calculate

The matrix

Against Kronecker power operation

It means performing once. For the index sets A and A ^c , sub-matrices consisting of rows corresponding to the indices are respectively

Wow

Is denoted as. Coded word through polar encoding

Can generate At this time, the code rate of the applied channel code is

It becomes.

의 변조차수에 대한 부반송파 수는

이고, 폴라 부호어는 변조기에 의하여 주파수 영역 심볼 블록

로 변조된다. 이때 주파수-도메인 심볼 블로의 길이는

이다. Of modulator 140

The number of subcarriers for the modulation order of

And the polar codeword is a frequency domain symbol block by a modulator.

Is modulated with At this time, the length of the frequency-domain symbol blow is

to be.

이고, 부반송파 간격은

이다. OFDM 신호의 복소 기저대역은 다음과 같이 나타낼 수 있다:

. OFDM modulation process through the IDFT 150, the symbol period is

And the subcarrier spacing

to be. The complex baseband of the OFDM signal can be represented as follows:

.

이고, 오버샘플링 개수는

이다.

번째 샘플은 다음과 같이 나타낼 수 있다:The oversampled time domain signal is

And the number of oversampling

to be.

The first sample can be represented as follows:

.

.

개의 샘플은

개의 제로 패딩과

-포인트의 역 이산 푸리에 변환(Inverse Fourier transform; IDFT) 를 통하여 구할 수 있다. OFDM 신호

에 대한 PAPR은 다음과 같다:

.

Dog samples

With zero padding

-It can be obtained by inverse Fourier transform (IDFT) of the point. OFDM signal

The PAPR for is as follows:

.

The technical problem to be achieved by the present invention is to generate a OFDM signal having a different PAPR stochastically by differently setting a non-frozen data block in an OFDM system with a polar code to solve a high PAPR problem in a mobile communication system with OFDM, It is to provide an optional mapping method and apparatus for selectively transmitting a signal having a minimum PAPR based on a method of setting a non-freezing data block differently.

In one aspect, the PAPR reduction method of a transmission apparatus of an OFDM communication system to which the polar code is proposed according to the present invention includes defining a set of a plurality of different frozen data blocks, each of a plurality of different frozen data blocks set Generating a plurality of OFDM signals having the same information but having different shapes, and selecting a signal having a minimum PAPR for a plurality of OFDM signals having different shapes and selecting a selective mapping (SLM). And transmitting by using.

The step of generating a plurality of OFDM signals having the same information for each set of a plurality of different frozen data blocks but having different shapes is different when the polo encoding is performed by inserting different frozen data blocks in the non-frozen data block. A codeword is generated, modulation is performed on the polar codeword to generate a plurality of different frequency domain symbol blocks, and OFDM modulation is performed to generate a plurality of different OFDM signals.

At this time, the step of selecting a signal having a minimum PAPR for a plurality of OFDM signals having different forms and transmitting them using a selective mapping (SLM) OFDM demodulation for a plurality of OFDM signals having different types Performing a process, repeatedly performing polar decoding on a plurality of different frozen data blocks, or decoding an information word using a plurality of parallel decoders, and transmitting a signal corresponding to a decoding result having the highest reliability, And outputting a corresponding decoding result.

According to another embodiment, the step of generating a plurality of OFDM signals including the same information for each of a plurality of different sets of frozen data blocks but having different forms is a frozen data block set as a zero vector in the non-frozen data block. To generate a polar codeword by encoding and to generate a plurality of different codewords by scrambling a sequence in the polar codeword, and the generated codewords are converted into a plurality of different OFDM signals using a modulator and an OFDM modulator. .

At this time, the step of selecting a signal having a minimum PAPR for a plurality of OFDM signals having different forms and transmitting them using a selective mapping (SLM) OFDM demodulation for a plurality of OFDM signals having different types Performing a process, repeatedly performing descrambling on a plurality of different sequences generated through the OFDM demodulation process, or decoding a codeword using a plurality of descramblers, multiple decoding on the decoded codeword Iteratively performs the polar decoding, or decoding the information word using a plurality of parallel decoders and transmitting a signal corresponding to the decoding result with the highest reliability, and outputting the decoding result.

In another aspect, the apparatus for transmitting an OFDM communication system to which the polar code is proposed according to the present invention includes a freeze data block set generation unit that defines a plurality of different freeze data block sets, and a plurality of different freeze data blocks. An OFDM signal generator for generating a plurality of OFDM signals having the same information for each set but having different types, and selecting a signal having a minimum PAPR for a plurality of OFDM signals having different types and selecting an optional mapping technique ( It includes an SLM signal selector for transmission using Selective mapping (SLM).

The OFDM signal generator generates different codewords when polo encoding is performed by different frozen bit blocks of the frozen data block set generator, and generates a plurality of different frequency domain symbol blocks by performing modulation on the polar codewords, By performing OFDM modulation, a plurality of different OFDM signals are generated.

At this time, the SLM signal selector performs an OFDM demodulation process on a plurality of OFDM signals having different forms, repeatedly performs polar decoding on a plurality of different frozen data blocks, or uses multiple parallel decoders for information words. Decode, transmit the signal corresponding to the decoding result with the highest reliability, and output the decoding result.

According to another embodiment, the OFDM signal generation unit generates a polar codeword by inserting and encoding a frozen data block set as a zero vector in a non-frozen data block, and generates a plurality of different codewords by scrambling a sequence in the polar codeword. The generated codeword is converted into a plurality of different OFDM signals using a modulator and an OFDM modulator.

At this time, the SLM signal selector performs an OFDM demodulation process on a plurality of OFDM signals having different forms, and repeatedly performs descrambling on a plurality of different sequences generated through the OFDM demodulation process, or Decode the codeword using a scrambler, repeatedly perform a plurality of polar decoding on the decoded codeword, or decode the information word using a plurality of parallel decoders, and obtain a signal corresponding to the decoding result with the highest reliability. Transmit and output the decoding result.

According to embodiments of the present invention, the PAPR of the OFDM system to which the polar code is applied can be reduced, and the transmission rate is not reduced by not transmitting additional information about which OFDM signal is transmitted. In addition, the transmission complexity and the number of transmission devices required to generate a plurality of OFDM signals may not be significantly increased, and a high PAPR problem of OFDM may be solved by using a polar code defined as a standard for a control channel of a 5G standard.

1 is a view showing a structure of a transmitter of an OFDM system to which a polar code is applied according to the prior art.
2 is a diagram illustrating a structure of a transmitting end of an OFDM system to which a polar code is applied using a selective mapping technique according to an embodiment of the present invention.
3 is a diagram illustrating a structure of a transmitter of an OFDM system to which a polar code is applied using a selective mapping technique according to another embodiment of the present invention.
4 is a flowchart of a transmission method for reducing PAPR in an OFDM communication system to which a polar code is applied according to an embodiment of the present invention.
5 is a flowchart illustrating a process of transmitting using a selective mapping technique according to an embodiment of the present invention.
6 is a flowchart illustrating a process of transmitting using a selective mapping technique according to another embodiment of the present invention.
7 is a graph showing the results of evaluating the PAPR reduction effect of the selective mapping technique according to an embodiment of the present invention.

In the present invention, a high PAPR problem in an OFDM system to which a polar code is applied is proposed and proposed by inventing and inventing an optional mapping technique using the polar code. According to an embodiment of the present invention, an OFDM signal having a different PAPR may be stochastically generated by differently setting a non-frozen data block in an OFDM system to which a polar code is applied. The transmitting apparatus of the proposed system uses a selective mapping technique that selectively transmits a signal with a minimum PAPR based on a method of differently setting a non-frozen data block. In other words, the polar coding technique is used for the selective mapping technique for generating multiple OFDM signals having different PAPRs with probability, and the proposed technique can be expected to reduce the PAPR of the OFDM system to which the polar codes are applied. In addition, the transmission rate is not lowered by not transmitting additional information about which OFDM signal is transmitted, and the transmission complexity and the number of transmission devices required to generate multiple OFDM signals are not significantly increased. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating a structure of a transmitting end of an OFDM system to which a polar code is applied using a selective mapping technique according to an embodiment of the present invention.

The structure of the transmitting end of the OFDM system to which the polar code using the proposed selective mapping technique is applied includes a frozen data block set generator 210, an OFDM signal generator 220, and an SLM signal selector 230.

The frozen data block set generation unit 210 includes a CRC encoder 211 and a plurality of frozen bit insertion units 212, ..., 213. The frozen data block set generation unit 210 defines a set of a plurality of different frozen data blocks.

개의 서로 다른 동결 데이터 블록의 집합

을 정의한다. 일반적으로 0번째 동결 데이터 블록의 경우 영벡터로 설정 가능 하다(

).

개의 동결 데이터 블록의 경우 무작위로 설정 가능하다. 동결 데이터 블록의 집합은 송수신단이 서로 공유하고 있는 정보이다. According to an embodiment of the present invention, the input transmitted through the CRC encoder 211 is through a plurality of freeze bit inserters 212, ..., 213.

Of four different freeze data blocks

Define Generally, it can be set as zero vector for the 0th freeze data block (

).

In case of two frozen data blocks, it can be set at random. The set of frozen data blocks is information shared by the transmitting and receiving terminals.

The OFDM signal generator 220 includes a plurality of polar encoders 221, ..., 222, a plurality of modulators 223, ..., 224, and a plurality of IDFTs 225, ..., 226. .

The OFDM signal generator 220 generates a plurality of OFDM signals having the same information but different forms for each of a plurality of different sets of frozen data blocks.

에 서로 다른 동결 데이터 블록을 삽입 후 복수의 폴라 부호화기(221, ..., 222)를 통해 폴로 부호화 진행 시 서로 다른 부호어

가 생성된다. 복수의 변조기(223, ..., 224)를 통해 폴라 부호어

에 대하여 변조를 수행함으로써

개의 서로 다른 주파수 영역 심볼 블록

을 생성한다. 그리고, 복수의 IDFT(225, ..., 226)를 통해 OFDM 변조를 수행함으로써

개의 서로 다른 OFDM 신호

를 생성한다. Non-freezing data block

After inserting different freeze data blocks into the Polo encoding process through a plurality of Polar encoders (221, ..., 222), different code words

Is created. Polar codeword through multiple modulators (223, ..., 224)

By performing modulation on

Blocks of different frequency domain symbols

Produces And, by performing OFDM modulation through a plurality of IDFT (225, ..., 226)

Different OFDM signals

Produces

The SLM signal selector 230 selects signals having a minimum PAPR for a plurality of OFDM signals having different forms and transmits them using a selective mapping (SLM).

개의 OFDM 신호에 대하여 최소의 PAPR을 갖는 신호

를 선택하여 전송할 수 있다. 선택된 신호는

로 결정되는 인덱스

에 대하여

로써 표현 가능하다. According to an embodiment of the present invention, different

Signal with minimum PAPR for 2 OFDM signals

You can select and send. The selected signal

Index determined by

about

Can be expressed as

번 반복하여 수행하거나,

개의 동결 비트 삽입기, 폴라 부호화기, 변조기, OFDM 변조기를 병렬적으로 동작 시킴으로써 실시될 수 있다. SLM technique according to an embodiment of the present invention is a conventional OFDM system transmission process

Repeat once, or

It can be implemented by operating two freeze bit inserters, polar encoders, modulators, and OFDM modulators in parallel.

In addition, since the SLM technique does not utilize additional information on which OFDM signal is transmitted, the receiving end can restore the transmitted signal through the following process.

개의 서로 다른 동결 데이터 블록

에 대하여 폴라 복호를 반복적으로 수행하거나,

개의 병렬 복호기를 이용하여 정보어를 복호화 할 수 있다. 이후, 가장 신뢰도 높은 복호 결과에 대응되는 신호가 전송되었다고 검출한 후 해당 복호 결과를 출력할 수 있다. First, an OFDM demodulation and demodulation process is performed on the received signal,

Different freeze data blocks

Repeatedly perform Polar decoding on, or

Information words can be decoded using two parallel decoders. Thereafter, after detecting that a signal corresponding to the most reliable decoding result has been transmitted, the corresponding decoding result can be output.

3 is a diagram illustrating a structure of a transmitter of an OFDM system to which a polar code is applied using a selective mapping technique according to another embodiment of the present invention.

The structure of a transmitter of an OFDM system to which a polar code is applied using a selective mapping technique according to another embodiment of the present invention includes a frozen data block set generator 310, an OFDM signal generator 320, and an SLM signal selector 330. Includes.

The frozen data block set generation unit 310 includes a CRC encoder 311 and a frozen bit insertion unit 312.

The OFDM signal generator 320 includes a polar encoder 321, a plurality of scramblers 322, ..., 323, a plurality of modulators 324, ..., 325, and a plurality of IDFTs 326, ..., 327).

The OFDM signal generator 220 generates a plurality of OFDM signals having the same information but different forms for each of a plurality of different sets of frozen data blocks.

에 대하여 다음의 식에 따라 시퀀스

를 정의할 수 있다: Index of SLM signal through polar encoder 321

For a sequence according to the following equation

You can define:

식 1

Equation 1

으로 설정 가능하기 때문에

이다. here

Because it can be set

to be.

번째 폴라 부호어는 다음 식과 같이 등가적으로 표현할 수 있다:

The second polar codeword can be equivalently expressed as:

식 2

Equation 2

번째 부호어

가 0 번째 부호어

에

를 스크램블링함으로써 생성될 수 있음을 의미한다. 식 2에 의하여 도 2의 SLM 송신단 구조를 효율적으로 변환하면 도 3과 같이 나타낼 수 있다. Expression 2

Codeword

Is the 0th codeword

on

Means that it can be created by scrambling. When the SLM transmission structure of FIG. 2 is efficiently converted by Equation 2, it can be expressed as in FIG. 3.

에 영벡터로 설정된 동결 데이터 블록

을 삽입 후 부호화함으로써 폴라 부호어

를 생성할 수 있다. Non-freezing data block

Freeze data block set to zero vector

Coded by inserting and encoding

Can generate

에 식 1로 구해진 시퀀스

,

를 스크램블링함으로써 서로 다른

개의 부호어

를 생성할 수 있다. 생성된

는 복수의 변조기(324, ..., 325)와 복수의 IDFT(326, ..., 327)를 이용하여 서로 다른

개의 OFDM 신호

로 변환된다. Polar codeword through multiple scramblers (322, ..., 323)

The sequence obtained by Equation 1

,

By scrambling

Two codewords

Can generate Generated

Is different using a plurality of modulators (324, ..., 325) and a plurality of IDFT (326, ..., 327)

OFDM signals

Is converted to

개의 OFDM 신호에 대하여 최소의 PAPR을 갖는 신호

를 선택하여 전송한다. SLM signal selection unit 330 is different

Signal with minimum PAPR for 2 OFDM signals

Select and send.

번 반복하여 수행하거나,

개의 스크램블러, 변조기, OFDM 변조기를 병렬적으로 동작 시킴으로써 실시될 수 있다. SLM technique according to another embodiment of the present invention is a scrambling, modulation, OFDM modulation process

Repeat once, or

It can be implemented by operating two scramblers, modulators, and OFDM modulators in parallel.

Since the proposed SLM technique does not utilize additional information about which OFDM signal is transmitted, the receiving end can restore the transmitted signal through the following process:

개의 서로 다른 시퀀스

에 대하여 디스크램블링을 반복적으로 수행하거나,

개의 디스크램블러를 이용하여 부호어를 복호화 할 수 있다.

번의 폴라 복호를 반복적으로 수행하거나,

개의 병렬 복호기를 이용하여 정보어를 복호화 할 수 있다. 이후, 가장 신뢰도 높은 복호 결과에 대응되는 신호가 전송되었다고 검출한 후 해당 복호 결과를 출력할 수 있다. First, an OFDM demodulation and demodulation process is performed on the received signal,

Different sequences

For descrambling repeatedly, or

Codewords can be decoded using two descramblers.

Repeatedly perform Polar decoding of times, or

Information words can be decoded using two parallel decoders. Thereafter, after detecting that a signal corresponding to the most reliable decoding result is transmitted, the corresponding decoding result can be output.

4 is a flowchart of a transmission method for reducing PAPR in an OFDM communication system to which a polar code is applied according to an embodiment of the present invention.

The proposed transmission method for reducing the PAPR of the OFDM communication system to which the polar code is applied is defined in step 410 of a plurality of different frozen data blocks, and the same information is provided for each of the plurality of different frozen data blocks. Step 420 of generating a plurality of OFDM signals having different shapes, but selecting a signal having a minimum PAPR for a plurality of OFDM signals having different shapes and using selective mapping (SLM) It may include the step of transmitting 430.

In step 410, a set of a plurality of different frozen data blocks is defined.

In step 420, a plurality of OFDM signals including the same information for each of a plurality of different sets of frozen data blocks but having different forms are generated. Hereinafter, a process of transmitting using the selective mapping technique according to an embodiment of the present invention will be described in more detail.

5 is a flowchart illustrating a process of transmitting using a selective mapping technique according to an embodiment of the present invention.

In step 420 according to an embodiment of the present invention, different frozen data blocks are inserted into non-frozen data blocks to generate different codewords during polo encoding. A plurality of different frequency domain symbol blocks are generated by performing modulation on the polar codeword, and a plurality of different OFDM signals are generated by performing OFDM modulation.

At this time, in step 430, a signal having a minimum PAPR is selected for a plurality of OFDM signals having different forms and transmitted using a selective mapping (SLM).

Step 430 according to an embodiment of the present invention is a step 510 of performing an OFDM demodulation process on a plurality of OFDM signals having different forms, and repeatedly performing polar decoding on a plurality of different frozen data blocks. Alternatively, it may include the step of decoding the information word using a plurality of parallel decoders (520) and transmitting a signal corresponding to the decoding result having the highest reliability, and outputting the decoding result (530).

As described with reference to FIG. 2, a signal having a minimum PAPR is selected for a plurality of OFDM signals having different shapes through the SLM signal selector 230 and transmitted using a selective mapping (SLM).

개의 OFDM 신호에 대하여 최소의 PAPR을 갖는 신호

를 선택하여 전송할 수 있다. 선택된 신호는

로 결정되는 인덱스

에 대하여

로써 표현 가능하다. According to an embodiment of the present invention, different

Signal with minimum PAPR for 2 OFDM signals

You can select and send. The selected signal

Index determined by

about

Can be expressed as

번 반복하여 수행하거나,

개의 동결 비트 삽입기, 폴라 부호화기, 변조기, OFDM 변조기를 병렬적으로 동작 시킴으로써 실시될 수 있다. SLM technique according to an embodiment of the present invention is a conventional OFDM system transmission process

Repeat once, or

It can be implemented by operating two freeze bit inserters, polar encoders, modulators, and OFDM modulators in parallel.

In addition, since the SLM technique does not utilize additional information on which OFDM signal is transmitted, the receiving end can restore the transmitted signal through the following process.

개의 서로 다른 동결 데이터 블록

에 대하여 폴라 복호를 반복적으로 수행하거나,

개의 병렬 복호기를 이용하여 정보어를 복호화 할 수 있다. 이후, 가장 신뢰도 높은 복호 결과에 대응되는 신호가 전송되었다고 검출한 후 해당 복호 결과를 출력할 수 있다.First, an OFDM demodulation and demodulation process is performed on the received signal,

Different freeze data blocks

Repeatedly perform Polar decoding on, or

Information words can be decoded using two parallel decoders. Thereafter, after detecting that a signal corresponding to the most reliable decoding result has been transmitted, the corresponding decoding result can be output.

6 is a flowchart illustrating a process of transmitting using a selective mapping technique according to another embodiment of the present invention.

In step 420 according to another embodiment of the present invention, a polar codeword is generated by inserting and encoding a frozen data block set as a zero vector into a non-freezing data block. A plurality of different codewords are generated by scrambling a sequence in the polar codeword, and the generated codewords are converted into a plurality of different OFDM signals using a modulator and an OFDM modulator.

At this time, in step 430, a signal having a minimum PAPR is selected for a plurality of OFDM signals having different forms and transmitted using a selective mapping (SLM).

Step 430 according to another embodiment of the present invention is a step 610 of performing an OFDM demodulation process on a plurality of OFDM signals having different forms, and a plurality of different sequences generated through the OFDM demodulation process Step 620 of repeatedly performing descrambling or decoding a codeword using a plurality of descramblers, repeatedly performing a plurality of polar decoding on the decoded codeword, or using a plurality of parallel decoders Decoding the word 630 and transmitting the signal corresponding to the decoding result with the highest reliability, and outputting the decoding result (640).

개의 OFDM 신호에 대하여 최소의 PAPR을 갖는 신호

를 선택하여 전송한다. As described with reference to Figure 3, the SLM signal selection unit 330 through different

Signal with minimum PAPR for 2 OFDM signals

Select and send.

번 반복하여 수행하거나,

개의 스크램블러, 변조기, OFDM 변조기를 병렬적으로 동작 시킴으로써 실시될 수 있다. SLM technique according to another embodiment of the present invention is a scrambling, modulation, OFDM modulation process

Repeat once, or

It can be implemented by operating two scramblers, modulators, and OFDM modulators in parallel.

Since the proposed SLM technique does not utilize additional information about which OFDM signal is transmitted, the receiving end can restore the transmitted signal through the following process:

개의 서로 다른 시퀀스

에 대하여 디스크램블링을 반복적으로 수행하거나,

개의 디스크램블러를 이용하여 부호어를 복호화 할 수 있다.

번의 폴라 복호를 반복적으로 수행하거나,

개의 병렬 복호기를 이용하여 정보어를 복호화 할 수 있다. 이후, 가장 신뢰도 높은 복호 결과에 대응되는 신호가 전송되었다고 검출한 후 해당 복호 결과를 출력할 수 있다.First, an OFDM demodulation and demodulation process is performed on the received signal,

Different sequences

For descrambling repeatedly, or

Codewords can be decoded using two descramblers.

Repeatedly perform Polar decoding of times, or

Information words can be decoded using two parallel decoders. Thereafter, after detecting that a signal corresponding to the most reliable decoding result has been transmitted, the corresponding decoding result can be output.

In the present invention, the selective mapping technique is considered through an approach such as applying a different phase or applying different scrambling, but the proposed transmission apparatus of the OFDM communication system to which the polar code is applied and the PAPR reduction method thereof have the characteristics of the polar code. It utilizes a new approach to generate OFDM signals with different PAPRs with probability. We propose a method of generating OFDM signals having different PAPRs using non-frozen data blocks inserted in a polar encoding process through a new selective mapping method using the polar codes.

Therefore, because the PAPR reduction technique is important due to the non-linear characteristics of the mounted power amplifier, the technology invented for a communication terminal utilizing OFDM is applicable. In particular, it is expected that the technology of the present invention can be applied to low-cost terminals applied to the following mobile communication scenarios and applications to create added value: low-cost terminals considered in 5GmMTC scenarios, low-power wide area (LPWA) applications Small base station that utilizes low cost terminals and low cost power amplifiers.

According to an embodiment of the present invention, a high PAPR problem of OFDM can be solved by using a polar code defined as a standard for a control channel of a 5G standard. In addition, it can be applied to a terminal of a 5G mobile communication system from the viewpoint of solving a high PAPR problem of OFDM, which is a waveform considered in the 5G standard, by using a polar code defined as a standard for a control channel of the 5G standard.

7 is a graph showing the results of evaluating the PAPR reduction effect of the selective mapping technique according to an embodiment of the present invention.

개의 서로 다른 PAPR을 갖는 OFDM 신호를 생성한 후 최소의 PAPR을 갖는 신호를 확률적으로 선택하여 전송하기 때문에 PAPR 감소시킬 수 있다. 또한, 단일 폴라 부호화기를 이용하여 한 번의 부호화 과정을 수행할 경우, 송신단의 장치 비용 절감 및 구동 효율을 향상시킬 수 있다. Since the proposed SLM technique does not utilize any additional information, there is no decrease in transmission rate. Also,

After generating OFDM signals having different PAPRs, the PAPR can be reduced because a signal having a minimum PAPR is randomly selected and transmitted. In addition, when a single encoding process is performed using a single polar encoder, it is possible to reduce a device cost of a transmitting end and improve driving efficiency.

Table 1 is a table showing an experimental environment for verifying the PAPR reduction effect according to an embodiment of the present invention.

<Table 1>

) 대비 제안된 SLM 기법(

) 적용 시 특정 PAPR을 가질 확률이 낮아짐을 확인할 수 있다. Referring to FIG. 7, PAPR reduction effect of the proposed SLM technique can be confirmed by observing a complementary cumulative distribution function (CCDF) for PAPR. Existing OFDM system(

) Compared to the proposed SLM technique (

) It can be seen that the probability of having a specific PAPR decreases when applied.

The device described above may be implemented with hardware components, software components, and/or combinations of hardware components and software components. For example, the devices and components described in the embodiments include, for example, processors, controllers, arithmetic logic units (ALUs), digital signal processors (micro signal processors), microcomputers, field programmable arrays (FPAs), It may be implemented using one or more general purpose computers or special purpose computers, such as a programmable logic unit (PLU), microprocessor, or any other device capable of executing and responding to instructions. The processing device may run an operating system (OS) and one or more software applications running on the operating system. In addition, the processing device may access, store, manipulate, process, and generate data in response to the execution of the software. For convenience of understanding, a processing device may be described as one being used, but a person having ordinary skill in the art, the processing device may include a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that may include. For example, the processing device may include a plurality of processors or a processor and a controller. In addition, other processing configurations, such as parallel processors, are possible.

The software may include a computer program, code, instruction, or a combination of one or more of these, and configure the processing device to operate as desired, or process independently or collectively You can command the device. Software and/or data may be interpreted by a processing device or to provide instructions or data to a processing device, of any type of machine, component, physical device, virtual equipment, computer storage medium or device. Can be embodied in The software may be distributed on networked computer systems, and stored or executed in a distributed manner. Software and data may be stored in one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, or the like alone or in combination. The program instructions recorded on the medium may be specially designed and constructed for the embodiments or may be known and usable by those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs, DVDs, and magnetic media such as floptical disks. -Hardware devices specifically configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language code that can be executed by a computer using an interpreter, etc., as well as machine language codes produced by a compiler.

As described above, although the embodiments have been described by a limited embodiment and drawings, those skilled in the art can make various modifications and variations from the above description. For example, the described techniques are performed in a different order than the described method, and/or the components of the described system, structure, device, circuit, etc. are combined or combined in a different form from the described method, or other components Alternatively, even if replaced or substituted by equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (10)

Defining a set of a plurality of different frozen data blocks;
Generating a plurality of OFDM signals including the same information for each of a plurality of different sets of frozen data blocks but having different forms; And
Selecting a signal having a minimum PAPR for a plurality of OFDM signals having different forms and transmitting them using a selective mapping (SLM)
Method for reducing PAPR OFDM transmission system comprising a. According to claim 1,
Generating a plurality of OFDM signals having the same information but different forms for each set of a plurality of different frozen data blocks,
By inserting different frozen data blocks in the non-freezing data block, different code words are generated during polo encoding, and modulation is performed on the polar code words to generate a plurality of different frequency domain symbol blocks and OFDM modulation is performed. Thereby generating a plurality of different OFDM signals
Method for reducing PAPR of an OFDM communication system transmitting device. According to claim 2,
The step of selecting a signal having a minimum PAPR for a plurality of OFDM signals having different forms and transmitting them using a selective mapping (SLM) method includes:
Performing an OFDM demodulation process on a plurality of OFDM signals having different forms;
Repetitively performing polar decoding on a plurality of different frozen data blocks or decoding an information word using a plurality of parallel decoders; And
Transmitting a signal corresponding to the decoding result with the highest reliability, and outputting the decoding result
Method for reducing PAPR OFDM transmission system comprising a. According to claim 1,
Generating a plurality of OFDM signals having the same information but different forms for each set of a plurality of different frozen data blocks,
A polar codeword is generated by inserting and encoding a frozen data block set as a zero vector into a non-freezing data block, and a plurality of different codewords are generated by scrambling a sequence in the polar codeword, and the generated codeword is a modulator and an OFDM modulator. To be converted into a plurality of different OFDM signals
Method for reducing PAPR of an OFDM communication system transmitting device. According to claim 4,
The step of selecting a signal having a minimum PAPR for a plurality of OFDM signals having different forms and transmitting them using a selective mapping (SLM) method includes:
Performing an OFDM demodulation process on a plurality of OFDM signals having different forms;
Performing descrambling repeatedly on a plurality of different sequences generated through the OFDM demodulation process, or decoding a codeword using a plurality of descramblers;
Repetitively performing a plurality of polar decoding on the decoded codeword, or decoding the information word using a plurality of parallel decoders; And
Transmitting a signal corresponding to the decoding result with the highest reliability, and outputting the decoding result
Method for reducing PAPR OFDM transmission system comprising a. A frozen data block set generation unit defining a set of a plurality of different frozen data blocks;
An OFDM signal generator for generating a plurality of OFDM signals having the same information but different forms for each of a plurality of different sets of frozen data blocks; And
SLM signal selection unit for selecting a signal having a minimum PAPR for a plurality of OFDM signals having different forms and transmitting using a selective mapping (SLM)
PAPR reduction apparatus of an OFDM communication system transmitting apparatus comprising a. The method of claim 6,
OFDM signal generation unit,
When the polo encoding is performed by different frozen bit blocks of the frozen data block set generation unit, different code words are generated, and modulation is performed on the polar code words to generate a plurality of different frequency domain symbol blocks and OFDM modulation is performed. Thereby generating a plurality of different OFDM signals
PAPR reduction device of an OFDM communication system transmission device. The method of claim 7,
SLM signal selector,
OFDM demodulation is performed on a plurality of OFDM signals having different forms;
Repeatedly performing polar decoding on a plurality of different frozen data blocks, or decoding an information word using a plurality of parallel decoders;
Transmit the signal corresponding to the decoding result with the highest reliability, and output the decoding result.
PAPR reduction device of an OFDM communication system transmission device. The method of claim 6,
OFDM signal generation unit,
A polar codeword is generated by inserting and encoding a frozen data block set as a zero vector into a non-freezing data block, a plurality of different codewords are generated by scrambling a sequence in the polar codeword, and the generated codeword is modulator and OFDM. Converting a plurality of different OFDM signals using a modulator
PAPR reduction device of an OFDM communication system transmission device. The method of claim 9,
SLM signal selector,
OFDM demodulation is performed on a plurality of OFDM signals having different forms;
Descrambled repeatedly for a plurality of different sequences generated through the OFDM demodulation process, or a codeword is decoded using a plurality of descramblers;
Decoding a plurality of polar decoding iteratively on the decoded codeword or decoding the information word using a plurality of parallel decoders;
Transmit the signal corresponding to the decoding result with the highest reliability, and output the decoding result.
PAPR reduction device of an OFDM communication system transmission device.

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