阅读说明：本技术 基于Arnold变换的OFDM系统峰值功率优化方法 (OFDM system peak power optimization method based on Arnold transformation ) 是由 王灵垠 胡驰 于 2019-11-19 设计创作，主要内容包括：本公开提供了一种基于Arnold变换的OFDM系统峰值功率优化方法,将原始输入的二进制数据序列分为多个子块序列并添加增广序列,将各个子块序列分别排成方阵,并逐一对各个方阵进行Arnold变换,然后各个方阵重新排列为候选子块序列,将各个候选子块序列重新组合为数据序列,将重新组合后的各个数据序列进行相移键控映射,得到对应的频域数据序列,将频域数据序列按照上述方式再次进行Arnold变换后得到重新组合的频域数据序列,将各个频域数据序列分别进行IFFT变换,获得对应的候选信号并计算其PAPR值,从全部候选信号中,选择PAPR值最小的候选信号进行传输；本公开在无需发送边信息的前提下获得与原始OFDM系统相似的误比特率。(The utility model provides an OFDM system peak power optimization method based on Arnold transform, which comprises dividing the originally input binary data sequence into a plurality of sub-block sequences and adding an augmentation sequence, arranging each sub-block sequence into square matrixes respectively, carrying out Arnold transform on each square matrix one by one, rearranging each square matrix into candidate sub-block sequences, recombining each candidate sub-block sequence into a data sequence, carrying out phase shift keying mapping on each recombined data sequence to obtain a corresponding frequency domain data sequence, carrying out Arnold transform on the frequency domain data sequence again according to the method to obtain a recombined frequency domain data sequence, carrying out IFFT transform on each frequency domain data sequence respectively to obtain a corresponding candidate signal and calculate the PAPR value thereof, and selecting the candidate signal with the minimum PAPR value from all candidate signals for transmission; the present disclosure achieves a bit error rate similar to the original OFDM system without the need to send side information.)

1. An OFDM system peak power optimization method based on Arnold transformation is characterized by comprising the following steps:

(1) dividing an original input binary data sequence into a plurality of sub-block sequences according to the length of the original input binary data sequence, and then adding an amplification sequence at the forefront end of each sub-block sequence to enable the length of each sub-block sequence to meet the requirement of Arnold transformation;

(2) respectively arranging each subblock sequence added with the augmentation sequence into square matrixes, carrying out Arnold transformation on each square matrix one by one, and rearranging each square matrix subjected to Arnold transformation into candidate subblock sequences;

(3) recombining each candidate sub-block sequence into a data sequence;

(4) carrying out binary phase shift keying mapping or quadrature phase shift keying mapping on each recombined data sequence to obtain a corresponding frequency domain data sequence;

(5) each frequency domain data sequence obtained by mapping is partitioned into a plurality of frequency domain sub-block sequences again, and an amplification sequence is added at the forefront end of each frequency domain sub-block sequence according to the Arnold transformation requirement, so that each frequency domain sub-block sequence can be arranged into a frequency domain square matrix;

(6) respectively arranging the frequency domain sub-block sequences added with the augmentation sequences into frequency domain square matrixes, carrying out Arnold transformation on the frequency domain square matrixes one by one, and then rearranging the frequency domain square matrixes subjected to Arnold transformation into candidate frequency domain sub-block sequences;

(7) recombining each candidate frequency domain sub-block sequence into a frequency domain data sequence;

(8) performing IFFT transformation on each frequency domain data sequence after recombination to obtain corresponding candidate signals;

(9) and calculating the PAPR values of all candidate signals, and selecting the candidate signal with the smallest PAPR value from the candidate signals for transmission.

2. The method as claimed in claim 1, wherein in step (1), the augmented sequence is a binary sequence, the elements are from the set {0,1}, and the length of each sub-block sequence after the augmented sequence is added can arrange the sequence into a square matrix.

3. The method for optimizing the peak power of the OFDM system based on the Arnold transform as claimed in claim 1, wherein in the step (2) and/or the step (6), when the sub-block sequences are arranged into the square matrix, the sub-block sequences are arranged in a row or a column;

or, in step (2) and/or step (6), the transformation matrix in the Arnold transformation is

4. The method for peak power optimization of an Arnold transform-based OFDM system as claimed in claim 1, wherein in step (5), if binary phase shift keying mapping is used in step (4), the augmented sequence in step (5) is composed of elements in the set {1, -1 }.

5. The Arnold transform-based OFDM system peak power optimization method of claim 4, wherein the binary phase shift keying mapping rule maps binary bit "0" to "-1" and binary bit "1" to "1".

6. The method for peak power optimization of an Arnold transform-based OFDM system as claimed in claim 1, wherein in step (5), if the quadrature phase shift keying mapping is used in step (4), the augmented sequence in step (5) is composed of elements in the set {1, -1, j, -j }.

7. The method as claimed in claim 6, wherein the mapping rule of quadrature phase shift keying is that the bit sequence "00" is mapped to "1", the bit sequence "01" is mapped to "j", the bit sequence "11" is mapped to "-1", and the bit sequence "10" is mapped to "-j".

8. An OFDM system peak power optimization system based on Arnold transformation, comprising:

a first signal splitting and amplification module configured to: dividing an original input binary data sequence into a plurality of sub-block sequences according to the length of the original input binary data sequence, and then adding an amplification sequence at the forefront end of each sub-block sequence to enable the length of each sub-block sequence to meet the requirement of Arnold transformation;

a first Arnold transformation module configured to: respectively arranging each subblock sequence added with the augmentation sequence into square matrixes, carrying out Arnold transformation on each square matrix one by one, and rearranging each square matrix subjected to Arnold transformation into candidate subblock sequences;

a first data sequence reassembling module configured to: recombining each candidate sub-block sequence into a data sequence;

a frequency domain data sequence generation module configured to: carrying out binary phase shift keying mapping or quadrature phase shift keying mapping on each recombined data sequence to obtain a corresponding frequency domain data sequence;

a second signal splitting and amplification module configured to: each frequency domain data sequence obtained by mapping is partitioned into a plurality of frequency domain sub-block sequences again, and an amplification sequence is added at the forefront end of each frequency domain sub-block sequence according to the Arnold transformation requirement, so that each frequency domain sub-block sequence can be arranged into a frequency domain square matrix;

a second Arnold transformation module configured to: respectively arranging the frequency domain sub-block sequences added with the augmentation sequences into frequency domain square matrixes, carrying out Arnold transformation on the frequency domain square matrixes one by one, and then rearranging the frequency domain square matrixes subjected to Arnold transformation into candidate frequency domain sub-block sequences;

a second data sequence reassembling module configured to: recombining each candidate frequency domain sub-block sequence into a frequency domain data sequence;

an inverse Fourier transform module configured to: performing IFFT transformation on each frequency domain data sequence after recombination to obtain corresponding candidate signals;

an optimal candidate signal selection module configured to: and calculating the PAPR values of all candidate signals, and selecting the candidate signal with the smallest PAPR value from the candidate signals for transmission.

9. A medium having a program stored thereon, wherein the program, when executed by a processor, implements the steps in the Arnold transform-based OFDM system peak power optimization method as claimed in any one of claims 1 to 7.

10. An electronic device comprising a memory, a processor and a program stored on the memory and executable on the processor, wherein the processor when executing the program implements the steps in the method for peak power optimization of an Arnold transform-based OFDM system as claimed in any of claims 1-7.

Technical Field

The present disclosure relates to the field of digital communication technologies, and in particular, to an Arnold transform-based method for optimizing peak power of an OFDM system.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier modulation technique that can divide a high-speed serial data signal into multiple parallel low-speed sub-channels. And then modulating the data to different orthogonal subcarriers by adopting different modulation techniques on each low-speed parallel subchannel to realize the parallel transmission of the sub-data streams. Because OFDM has the capability of resisting multipath fading and the capability of adapting to channel variations, this technique can be widely applied to various digital transmission and communication systems, such as High-bit-rate digital Subscriber Line (HDSL), Asymmetric Digital Subscriber Line (ADSL), fifth-generation mobile communication (5th generation mobile networks), and so on. Although the OFDM technique has many advantages and is widely used, the excessive peak power generated by the superposition of its own multi-channel time domain sub-signals exceeds the linear working range of the high-power amplifier, which causes the problems of distortion and interference in the signal received by the receiving end.

As a typical multi-carrier technique, the time domain expression of a discrete OFDM signal is:

wherein N represents the number of subcarriers, X_nRepresenting the frequency domain subcarrier signal.

Since an OFDM signal is a superposition of N subcarrier signals, excessive signal peak power is also generated. When a plurality of subcarrier signals have the same or similar initial phases, the superposed signals will generate larger signal peaks, and the larger signal peaks will cause the radio frequency power amplifier to exceed the linear working area, resulting in signal distortion. This parameter of an OFDM signal is typically characterized by a Peak-to-Average Power Ratio (PAPR) in the art.

The PAPR of an OFDM signal is defined as the ratio of the peak power to the average power of the signal, i.e.:

wherein E {. and max {. mean } represent the average and maximum values of the signal power, respectively.

In practical applications in the field, a Complementary Cumulative Distribution Function (CCDF) is often used to measure the probability distribution of the PAPR value of the OFDM signal, so as to estimate the PAPR performance of the OFDM system, and is defined as:

wherein the PAPR₀Representing a preset threshold.

The OFDM technology is clearly limited in its application due to its own disadvantage of having a large PAPR. For many years, scholars both at home and abroad have proposed numerous highly effective solutions. Depending on the mode of action of these methods, there are three main categories: signal predistortion class, coding class and probability class schemes. The signal predistortion method mainly implements peak reduction of a signal by clipping and filtering a high-peak signal, which is the easiest and most widely applied way. The encoding method selects code words which can minimize or reduce the PAPR for transmission by adopting various different encoding schemes, so as to achieve the purpose of reducing the PAPR of the system. As for the probability scheme, a series of phase rotation factors are adopted to rotate the phase of the data sequence, so as to reduce the signal peak probabilistically and achieve the purpose of reducing the signal PAPR.

The inventors of the present disclosure found that, although the probabilistic class technique has the best PAPR reduction performance, it also has its disadvantages: although it reduces PAPR of the system probabilistically by rotating the data sequence in phase at the transmitting end, it is not known at the receiving end what phase rotation has occurred in the data sequence, so side information needs to be transmitted along with the signal to help the receiving end demodulate the received signal. After the side information is interfered by the noise of the wireless channel, the side information is often recovered by errors at the receiving end, so that the signals are demodulated incorrectly at the receiving end, and the system is seriously distorted.

Disclosure of Invention

In order to solve the defects of the prior art, the disclosure provides an OFDM system peak power optimization method based on Arnold transformation, which can not only obtain better PAPR performance than the original OFDM system, but also obtain Bit Error Rate (BER) performance similar to the original OFDM system on the premise of not sending side information.

In order to achieve the purpose, the following technical scheme is adopted in the disclosure:

the first aspect of the disclosure provides an OFDM system peak power optimization method based on Arnold transformation.

An OFDM system peak power optimization method based on Arnold transformation comprises the following steps:

(1) dividing an original input binary data sequence into a plurality of sub-block sequences according to the length of the original input binary data sequence, and then adding an amplification sequence at the forefront end of each sub-block sequence to enable the length of each sub-block sequence to meet the requirement of Arnold transformation;

(2) respectively arranging each subblock sequence added with the augmentation sequence into square matrixes, carrying out Arnold transformation on each square matrix one by one, and rearranging each square matrix subjected to Arnold transformation into candidate subblock sequences;

(3) recombining each candidate sub-block sequence into a data sequence;

(4) performing Binary Phase Shift Keying (BPSK) mapping or Quadrature Phase Shift Keying (QPSK) mapping on each recombined data sequence to obtain a corresponding frequency domain data sequence;

(5) each frequency domain data sequence obtained by mapping is partitioned into a plurality of frequency domain sub-block sequences again, and an amplification sequence is added at the forefront end of each frequency domain sub-block sequence according to the Arnold transformation requirement, so that each frequency domain sub-block sequence can be arranged into a frequency domain square matrix;

(6) respectively arranging the frequency domain sub-block sequences added with the augmentation sequences into frequency domain square matrixes, carrying out Arnold transformation on the frequency domain square matrixes one by one, and then rearranging the frequency domain square matrixes subjected to Arnold transformation into candidate frequency domain sub-block sequences;

(7) recombining each candidate frequency domain sub-block sequence into a frequency domain data sequence;

(8) performing IFFT transformation on each frequency domain data sequence after recombination to obtain corresponding candidate signals;

(9) and calculating the PAPR values of all candidate signals, and selecting the candidate signal with the smallest PAPR value from the candidate signals for transmission.

As some possible implementations, in step (1), the augmented sequence is a binary sequence, the elements are from the set {0,1}, and the length of each sub-block sequence after adding the augmented sequence can arrange the sequence into a square matrix.

As some possible implementation manners, in the step (2) and/or the step (6), when the subblock sequences are arranged into a square matrix, the subblock sequences are arranged in a row manner or a column manner;

as some possible implementation manners, in the step (2) and/or the step (6), the transformation matrix in the Arnold transformation is

As some possible implementations, in step (5), if binary phase shift keying mapping is employed in step (4), the augmented sequence in step (5) is composed of elements in the set {1, -1 }.

By way of further limitation, the binary phase shift keying mapping rule maps binary bit "0" to "-1" and binary bit "1" to "1".

As some possible implementations, in step (5), if the quadrature phase shift keying mapping is adopted in step (4), the augmented sequence in step (5) is composed of elements in the set {1, -1, j, -j }.

By way of further limitation, the quadrature phase shift keying mapping rule is that bit sequence "00" is mapped to "1", bit sequence "01" is mapped to "j", bit sequence "11" is mapped to "-1", and bit sequence "10" is mapped to "-j".

A second aspect of the present disclosure provides an Arnold transform-based OFDM system peak power optimization system.

An OFDM system peak power optimization system based on Arnold transformation, comprising:

a first signal splitting and amplification module configured to: dividing an original input binary data sequence into a plurality of sub-block sequences according to the length of the original input binary data sequence, and then adding an amplification sequence at the forefront end of each sub-block sequence to enable the length of each sub-block sequence to meet the requirement of Arnold transformation;

a first Arnold Transformation Module (ATM) configured to: respectively arranging each subblock sequence added with the augmentation sequence into square matrixes, carrying out Arnold transformation on each square matrix one by one, and rearranging each square matrix subjected to Arnold transformation into candidate subblock sequences;

a first data sequence reassembling module configured to: recombining each candidate sub-block sequence into a data sequence;

a frequency domain data sequence generation module configured to: carrying out binary phase shift keying mapping or quadrature phase shift keying mapping on each recombined data sequence to obtain a corresponding frequency domain data sequence;

a second signal splitting and amplification module configured to: each frequency domain data sequence obtained by mapping is partitioned into a plurality of frequency domain sub-block sequences again, and an amplification sequence is added at the forefront end of each frequency domain sub-block sequence according to the Arnold transformation requirement, so that each frequency domain sub-block sequence can be arranged into a frequency domain square matrix;

a second Arnold Transform Module (ATM) configured to: respectively arranging the frequency domain sub-block sequences added with the augmentation sequences into frequency domain square matrixes, carrying out Arnold transformation on the frequency domain square matrixes one by one, and then rearranging the frequency domain square matrixes subjected to Arnold transformation into candidate frequency domain sub-block sequences;

a second data sequence reassembling module configured to: recombining each candidate frequency domain sub-block sequence into a frequency domain data sequence;

an inverse Fourier transform module configured to: performing IFFT transformation on each frequency domain data sequence after recombination to obtain corresponding candidate signals;

an optimal candidate signal selection module configured to: and calculating the PAPR values of all candidate signals, and selecting the candidate signal with the smallest PAPR value from the candidate signals for transmission.

A third aspect of the present disclosure provides a medium, on which a program is stored, which when executed by a processor implements the steps in the method for optimizing peak power of an Arnold transform-based OFDM system according to the first aspect of the present disclosure.

A fourth aspect of the present disclosure provides an electronic device, which includes a memory, a processor, and a program stored in the memory and executable on the processor, and when the processor executes the program, the processor implements the steps in the method for optimizing peak power of an OFDM system based on Arnold transform according to the first aspect of the present disclosure.

Compared with the prior art, the beneficial effect of this disclosure is:

1. the content of the present disclosure is based on Arnold transformation, data to be transmitted in an OFDM system is regarded as pixel points in an image, and phase consistency among subcarrier signals is broken through the Arnold transformation, so that the purpose of improving PAPR performance of the system is achieved.

2. The content disclosed by the disclosure can not only obtain better PAPR performance than that of the original OFDM system, but also obtain bit error rate performance similar to that of the original OFDM system on the premise of not sending side information.

3. The content disclosed by the disclosure is subjected to the first Arnold transformation in the time domain, is converted into the frequency domain to be subjected to the second Arnold transformation, and through the two times of Arnold transformation in the time domain and the frequency domain, the phase consistency among all subcarrier signals is further broken, and the capability of improving the PAPR performance of a system is greatly improved.

Drawings

Fig. 1 is a schematic block diagram of a peak power optimization method for an OFDM system based on Arnold transform according to embodiment 1 of the present disclosure.

Fig. 2 is a schematic block diagram of the ATM module in fig. 1 according to embodiment 1 of the present disclosure.

Fig. 3 is a schematic diagram of two arrangement modes for arranging sequences into a square matrix according to embodiment 1 of the present disclosure.

Fig. 4 is a PAPR performance graph of the original OFDM system and the method of the present disclosure when 81 subcarriers are used, which is provided in embodiment 1 of the present disclosure.

Fig. 5 is a graph of BER performance of the original OFDM system and the method of the present disclosure when an additive white gaussian noise channel and a rayleigh channel are used according to embodiment 1 of the present disclosure.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The embodiments and features of the embodiments in the present application may be combined with each other without conflict.