阅读说明：本技术 一种基于wfrft的数据块内部能量交织ofdm信号传输方法 (WFRFT-based data block internal energy interleaving OFDM signal transmission method ) 是由 沙学军 宋鸽 房宵杰 杨林森 侯静 冯雨晴 李成方 于 2019-11-22 设计创作，主要内容包括：一种基于WFRFT的数据块内部能量交织OFDM信号传输方法,涉及无线通信技术领域,是为了解决在信道存在突发错的情况下,某一符号发生深衰,对于出错的符号缺少信号层保障方法,进而导致系统性能受到限制的问题,本发明提出一种基于数据块内变换域能量交织的OFDM信号传输方法,在一个数据块内,通过对信号进行扩展加权分数傅里叶变换,将信号能量在时频平面完成交织,相比于不改变信号能量分布的传统符号交织,能量交织增加了对于出错的符号的信号层保障,将一个符号的能量与其他多个符号混合扩展,在能量上实现了符号的时频交织,当一个符号在传输中发生损失时,由于能量交织,该符号的能量损失被分散到了所有参与交织的符号上,而减少了单个符号的损失,使接收端可以还原该符号,提升了系统的抗干扰性能。(The invention discloses an OFDM signal transmission method based on WFRFT data block internal energy interleaving, relating to the technical field of wireless communication and aiming at solving the problems that under the condition that a channel has burst errors, a certain symbol is deeply attenuated, and a signal layer guarantee method is lacked for the erroneous symbol, thereby causing the limitation of system performance, the invention provides an OFDM signal transmission method based on data block internal transform domain energy interleaving, in a data block, signal energy is interleaved in a time-frequency plane by carrying out expansion weighted fractional Fourier transform on the signal, compared with the traditional symbol interleaving without changing the signal energy distribution, the energy interleaving increases the signal layer guarantee for the erroneous symbol, the energy of one symbol is mixed and expanded with other symbols, the time-frequency interleaving of the symbol is realized in energy, when one symbol is lost in transmission, due to energy interleaving, the energy loss of the symbol is dispersed to all the symbols participating in interleaving, so that the loss of a single symbol is reduced, the receiving end can restore the symbol, and the anti-interference performance of the system is improved.)

1. A WFRFT-based data block internal energy interleaving OFDM signal transmission method is characterized in that:

the signal transmitting method comprises the following steps:

step one, performing baseband mapping on 0 and 1 bit data generated by an information source to obtain a modulation result after constellation mapping;

step two, performing serial/parallel conversion on the modulation result obtained in the step one to obtain M paths of parallel signals X, wherein each path of signals is N points;

step three, performing energy interleaving on the M paths of parallel signals X obtained in the step two to obtain M paths of parallel signals F of the signals X subjected to energy interleaving in a data block transform domain;

performing IDFT (inverse discrete Fourier transform) on the M paths of parallel signals F subjected to energy interleaving obtained in the step three to obtain X paths of OFDM signals K subjected to energy interleaving of a transform domain;

step five, adding CP to each OFDM signal K obtained in the step four;

step six, performing parallel/serial conversion on the signal added with the CP obtained in the step five to obtain a path of serial signal;

seventhly, performing digital-to-analog conversion on the one path of serial signals obtained in the sixth step to obtain analog modulation signals;

step eight, carrying out up-conversion processing on the analog signal obtained in the step seven, and transmitting the signal after the up-conversion processing to a channel;

the signal receiving method comprises the following steps:

step nine, the signal reaches a receiving end through the transmission of a channel, and a receiver carries out down-conversion processing on the received signal to obtain a signal after down-conversion processing;

tenthly, performing analog-to-digital conversion on the processed signal obtained in the step nine to obtain a path of serial digital signal;

eleven, performing serial/parallel conversion on one path of serial digital signals obtained in the step ten to obtain M paths of parallel OFDM signals containing CP;

step twelve, respectively carrying out CP removing operation on each path of OFDM signals obtained in the step eleven to obtain M paths of parallel signals K%;

thirteen, performing DFT conversion on K% of the M paths of parallel signals obtained in the twelfth step to obtain F% of the M paths of parallel signals;

fourteen, performing energy de-interleaving operation on F% of the M paths of parallel signals obtained in the thirteen step to obtain X% of the M paths of parallel signals subjected to energy de-interleaving of a transform domain in the data block;

fifteen, performing parallel/serial conversion on the M paths of parallel signals obtained in the fourteenth step to obtain a path of serial signal;

sixthly, constellation demapping is carried out on the path of serial signals obtained in the fifteenth step, and original 0 and 1 bit data streams are restored.

2. The method according to claim 1, wherein the method for interleaving the energy of the M parallel signals X obtained in step two in the step three comprises:

performing parameter theta on the M paths of parallel signals X obtained in the step two₀,θ₁,θ₂,θ₃∈ [0,2 pi) to obtain M paths of parallel signals of X through energy interleaving of transform domainNumber F, the specific form of the data after the extended weighted score fourier transform is:

F(X₀)＝ω₀X₀+ω₁X₁+ω₂X₂+ω₃X₃；

in the formula, X₀As the original vector, X₁Is the vector of original vector after Fourier transformation, X₂Is an original vector X₀Amount of reversal of (2), X₃Is a post-Fourier transform vector X₁Amount of reversal of (w)₀,w₁,w₂,w₃The weighting coefficient is expressed in the following specific form:

wherein, theta₀,θ₁,θ₂,θ₃∈ [0,2 π) is the angle parameter.

3. The method of claim 1, wherein in step fourteen, the M parallel signals obtained in step thirteen are transmitted according to the WFRFT-based data block internal energy interleaving OFDM signal transmission method

DFT obtained in the third stepEnergy de-interleaved output signal vector

in the formula, X₀Is branch 0 original vector, X₁Is the vector of branch 1 after Fourier transformation, X₂For branch 2 original vector X₀Amount of reversal of (2), X₃Fourier transformed vector X for branch 3₁The amount of reverse rotation of (a) is,the weighting coefficient is inverse transformation, and the specific expression is as follows:

wherein, theta₀,θ₁,θ₂,θ₃∈ [0,2 π) is the same angle parameter as the emitter.

Technical Field

The invention relates to the technical field of wireless communication, in particular to an OFDM signal transmission method based on transform domain energy interleaving.

Background

Orthogonal frequency division multiplexing is a high-speed transmission technology in a wireless environment, and the main idea is to distribute high-speed data streams to a plurality of parallel orthogonal subcarriers through serial-to-parallel conversion and simultaneously transmit the data.

The principle of interleaving coding as a signal processing means for resisting burst errors existing in a channel is that an interleaver at a transmitting end and a de-interleaver at a receiving end are utilized to reform a burst channel with memory into a random independent error channel so as to be more suitable for channel coding for correcting the random independent errors for utilization, and the characteristic also enables the interleaving and de-interleaving technology to be widely applied to most communication systems.

However, under the condition that burst errors exist in a channel, a certain symbol is deeply faded, and the traditional symbol interleaving technology does not change the energy distribution of the signal, so that the energy loss of the symbol cannot be compensated, namely, a signal layer guarantee method is lacked for the erroneous symbol, and the system performance is limited.

Disclosure of Invention

The invention provides a WFRFT-based data block internal energy interleaving OFDM signal transmission method, aiming at solving the problem that under the condition that burst errors exist in a channel, a certain symbol is deeply attenuated, and a signal layer guarantee method is lacked for the erroneous symbol, so that the system performance is limited.

The OFDM signal transmission method based on transform domain energy interleaving comprises the following signal transmitting processes:

step one, performing baseband mapping on 0 and 1 bit data generated by an information source to obtain a modulation result after constellation mapping;

step two, carrying out serial/parallel conversion on the modulation result obtained in the step one to obtain M paths of parallel signals X, and N points of each path of signals;

step three, the M paths of parallel signals X obtained in the step two pass through an energy interleaver to obtain M paths of parallel signals F of X which pass through the energy interleaving of the transform domain in the data block;

step four, performing IDFT on the M paths of parallel signals F subjected to energy interleaving and obtained in the step three to obtain an OFDM signal K subjected to energy interleaving of the transform domain;

step five, adding CP to each OFDM symbol obtained in the step four;

step six, performing parallel/serial conversion on the signal added with the CP obtained in the step five to obtain a path of serial signal;

step seven, passing the one-path serial signal obtained in the step six through a digital/analog converter to obtain an analog modulation signal;

step eight, carrying out up-conversion processing on the analog signal obtained in the step seven, and transmitting the signal after the up-conversion processing to a channel;

the signal receiving process comprises the following steps:

step nine, the signal reaches a receiving end through the transmission of a channel, and a receiver carries out down-conversion processing on the received signal to obtain a signal after down-conversion processing;

step ten, passing the processed signal obtained in the step nine through an analog/digital converter to obtain a path of serial digital signal;

eleven, performing serial/parallel conversion on the one-path signal obtained in the step ten to obtain an OFDM signal containing the CP;

step twelve, each OFDM symbol obtained in the step eleven is respectively subjected to CP removing operation to obtain M paths of parallel signals

Thirteen step, the M paths of parallel signals obtained in the step twelve

DFT is carried out to obtain M paths of parallel signals

Step fourteen, the M paths of parallel signals obtained in the step thirteen are processedObtaining M paths of parallel signals subjected to energy deinterleaving in a transform domain in a data block through an energy deinterleaver

Fifteen, performing parallel/serial conversion on the M paths of parallel signals obtained in the fourteenth step to obtain a path of serial signal;

sixthly, constellation demapping is carried out on the one path of signals obtained in the fifteenth step, and 0 and 1 bit data streams are recovered.

In the third step, the M paths of parallel signals X obtained in the second step are subjected to energy interweaving, and the specific method is that the parameters of the M paths of parallel signals X are theta₀,θ₁,θ₂,θ₃∈ [0,2 π), to obtain M parallel signals F with X interleaved through transform domain energy, wherein the data after the Fourier transform is in the following specific form:

F(X₀)＝ω₀X₀+ω₁X₁+ω₂X₂+ω₃X₃；

in the formula, X₀As the original vector, X₁Is the vector of original vector after Fourier transformation, X₂Is an original vector X₀Amount of reversal of (2), X₃Is a post-Fourier transform vector X₁Amount of reversal of (w)₀,w₁,w₂,w₃The weighting coefficient is expressed in the following specific form:

in a fourteenth step, the original signal obtained in the thirteenth stepBy de-interleaving, by performing a parameter of θ₀,θ₁,θ₂,θ₃∈ [0,2 pi) to complete the de-interleaving process of energy to obtain signal

M-path parallel signals subjected to transform domain energy de-interleavingThe specific form of the data after the inverse Fourier transform of the expanded weighted fraction is as follows:

in the formula, X₀As the original vector, X₁Is the vector of original vector after Fourier transformation, X₂Is an original vector X₀Amount of reversal of (2), X₃Is a post-Fourier transform vector X₁The amount of reverse rotation of (a) is,the weighting coefficient is inverse transformation, and the specific expression is as follows:

in the third step and the fourteenth step, theta₀,θ₁,θ₂,θ₃∈ [0,2 π) is an angle parameter, the choice of which determines the distribution of energy in the time-frequency plane.

The invention provides an OFDM signal transmission method based on transform domain energy interleaving in a data block, which interleaves signal energy in a time-frequency plane by performing expansion weighted fractional Fourier transform on the signal in the data block, compared with the traditional symbol interleaving without changing the distribution of the signal energy, the energy interleaving increases the signal layer guarantee for error symbols, mixes and expands the energy of one symbol with other symbols, realizes the time-frequency interleaving of the symbols in energy, when one symbol is lost in transmission, because of the energy interleaving, the energy loss of the symbol is dispersed to all symbols participating in interleaving, and reduces the loss of a single symbol, so that a receiving end can restore the symbol, the anti-interference performance of the system is improved, and meanwhile, the data block after interleaving is subjected to signal processing such as conventional OFDM or FBMC, GFDM, UFMC and the like, the formed output signal still has the form of the original system signal, and has complete signal compatibility with the existing multi-carrier transmission system.

Drawings

Fig. 1 is a schematic diagram of the signal transmission flow of the present invention.

Fig. 2 is a schematic diagram of energy interleaving.

Fig. 3 is a diagram of simulation comparison curves of the bit error rate performance of the OFDM system in the case of using the energy interleaving mode, the conventional interleaving mode, and without interleaving operation.

Detailed Description