WO2020005118A1

WO2020005118A1 - Orthogonal frequency division multiplexing method and device for the implementation thereof

Info

Publication number: WO2020005118A1
Application number: PCT/RU2019/050094
Authority: WO
Inventors: Денис Владимирович УРСОЛ
Original assignee: Общество с ограниченной ответственностью "РВ-СИСТЕМС"
Priority date: 2018-06-26
Filing date: 2019-06-25
Publication date: 2020-01-02
Also published as: RU2702258C1

Abstract

The invention relates to communication technology and can be used for generating and processing a signal based on an orthogonal basis of eigenvectors of a sub-band matrix. The technical effect of the claimed group of inventions consists in a low level of out-of-band emission of communication signals. To achieve this, information to be transmitted is used to generate a signal with channel multiplexing based on an orthogonal basis of eigenvectors of a sub-band matrix, calculated for a given frequency range or set of frequency ranges in a given frequency band. On the receiving side, the trusted recovery of information from the received signal is provided. In the receiving/transmitting equipment, any modifications can be used before and after orthogonal multiplexing based on eigenvectors of a sub-band matrix, intended to improve transmission speed, reliability, noise immunity and efficiency, reduce energy expenditure and increase calculating speed and other parameters.

Description

METHOD FOR ORTHOGONAL FREQUENCY SEALING AND ITS

IMPLEMENTING DEVICE

FIELD OF TECHNOLOGY

The invention relates to the field of wired, satellite and terrestrial radio communications and can be used for transmission and reception (encoding and decoding) of information in systems with orthogonal frequency division multiplexing (OFDM).

BACKGROUND

Orthogonal frequency division multiplexing (OFDM) has also been known in the art since at least the late 1960s. In OFDM, a single transmitter transmits simultaneously at many different orthogonal frequencies. In OFDM, the available frequency band is subdivided into a number of identical “subchannel” bands. Orthogonal frequency division multiplexing is widely used in wireless communications, as it reduces mutual interference or crosstalk between signal transmissions, which ultimately allows data transmission with higher bandwidth and fewer errors. Currently, OFDM is used in many wireless communication standards [1, 2].

The OFDM method operates by splitting one high-speed information stream into several low-speed information streams, which are then transmitted simultaneously (in parallel). Each low speed stream is used to modulate the subcarrier. This creates a multi-frequency transmission by dividing a wide frequency band (channel) into several narrow frequency ranges, each of which is modulated by the signal stream.

In an OFDM system, a transmitter receives input in the frequency domain and converts them into a time-domain signal. The carrier wave is modulated by a time domain signal for wireless transmission. The receiver receives the signal, demodulates the wave and converts the signal back to the frequency domain for further processing.

The prototype of the invention, transmitting and restoring information, may be the device described in the patent [1]. The prototype diagram is presented in figure 1., where the transmitted OFDM signal can be generated transmitter 100. In the illustrated embodiment, the input data stream 101 is supplied by an application to the OFDM transmitter 100. In a standard TCP / IP communication protocol stack, this data can be received at the physical or data transfer control layer; the invention is not limited to any particular data source or mechanism for transmitting data to a transmitter, and may be embodied in hardware or software and at various levels of a network protocol stack. The serial to parallel conversion buffer 102 splits the serial data stream into several parallel data streams. The number of parallel data streams is equal to the number of subchannels selected for OFDM radio transmission. Then, each of the parallel data streams generated by the serial to parallel conversion buffer 102 is sent to the multi-carrier modulator 103. A multicarrier modulator 103 modulates each selected subchannel with each of the parallel data streams. The multicarrier modulator 103 can be efficiently implemented using an inverse fast Fourier transform algorithm to calculate a time domain signal. The multicarrier modulator 103 may use any modulation scheme to modulate each of the incoming data streams. In a preferred embodiment, the signals are modulated using quadrature amplitude modulation (QAM). Any QAM group may be used. For example, a modulator may use 16-QAM (hexadecimal), 64-QAM, 128-QAM, or 256-QAM. The modulation scheme may be selected based on the desired data rate, available subchannels, noise on each subchannel, or other factors. A cyclic prefix that acts as a guard interval is added to each of the parallel modulated waves in step 104. Then, parallel streams with a cyclic prefix are combined back into one serial stream in step 104. The cyclic prefix can be added after the procedure of combining the parallel stream into one serial stream, as an alternative to the above. Finally, the digital data stream is converted into an analog signal in a digital-to-analog converter 105 and output for wireless transmission, for example, to a quadrature modulator (not shown in the prototype diagram).

The transmitted OFDM signal may be received by the software receiver and processed to obtain a stream of original data. As is known in the art, the signal is first received by the receiving antenna and fed to the quadrature demodulator (not shown in the prototype diagram) and then the analog signal is converted back to a digital signal using an analog-to-digital converter 111. The cyclic prefix is removed and the individual subcarriers are converted back to separate streams in block 112. Each parallel data stream is demodulated using a demodulator 113 carrier sets using the Fast Fourier Transform algorithm. Finally, in block 114, the parallel streams are again assembled into a single serial digital stream 115 for further processing.

The disadvantages of the known solution include the use of the orthogonal Fourier basis for sealing the transmission channels used in block 103, since additional protective frequency intervals are required to reduce the level of out-of-band signal emission and inter-channel interference, which reduces the transmission rate of useful information.

Presented in Fig.6 and Fig.7 the energy spectra of channel signals with the release of the specified frequency ranges and without generated by the classical OFDM method using the Fourier basis, in comparison with the method proposed in this invention, confirms this opinion. As can be seen in the figures, the low level of out-of-band radiation of the signals generated by the proposed method (- 170 dB) allows you to reduce the protective frequency intervals (thereby increasing the speed), and also allows you to effectively cut out unused frequency intervals, with minimal impact on adjacent channels.

SUMMARY OF THE INVENTION

The problem to which the invention is directed is to create a method (s) and a device (s) for generating and processing a signal based on the orthogonal basis of the eigenvectors of the subband matrix, allowing to achieve a technical result.

The technical result of the claimed group of inventions is to provide a low level of out-of-band emission of communication signals.

An additional technical result is:

• reduction of inter-channel interference;

• the ability to exclude frequency ranges from the used frequency band;

• improvement of noise immunity of communication; • increase the transmission rate of useful information;

• reduction in performance requirements for computing resources and an increase in the speed of signal generation / restoration.

The essence of the invention is to form a signal with channel compression from the transmitted information on the basis of the orthogonal basis of the eigenvectors of the subband matrix, calculated for a given frequency range or a set of frequency ranges in a given frequency band. On the receiving side, it is possible to reliably recover information from the received signal.

In the receiving / transmitting equipment, any modifications can be used before and after orthogonal compaction based on the eigenvectors of the subband matrix, aimed at improving the transmission speed, reliability, noise immunity, efficiency, reducing the level of energy costs, increasing the speed of calculation and other parameters.

The technical result of the claimed group of inventions is achieved due to the fact that:

1. The following characteristic features are introduced into the signal conditioning method:

- calculate the elements of the subband matrix for the given frequency ranges;

- form a set of eigenvalues and the corresponding set of eigenvectors of a subband matrix calculated for given frequency ranges;

- the eigenvectors of the subband matrix are sampled based on their corresponding eigenvalues, in accordance with the specified transmission parameters;

- based on the calculated and selected eigenvectors and transmitted information, a signal is generated.

The signal is formed on the basis of calculated and selected eigenvectors by a matrix or element-by-element method.

The above method allows you to generate a signal with a low level of out-of-band radiation.

2. In the method of restoring the transmitted information, the following characteristic features have been introduced:

- calculate the elements of the subband matrix for the given frequency ranges; - form a set of eigenvalues and the corresponding set of eigenvectors of a subband matrix calculated for given frequency ranges;

- the eigenvectors of the subband matrix are sampled based on the corresponding eigenvalues of the subband matrix, in accordance with the specified transmission parameters;

- based on the calculated and selected eigenvectors that have passed the complex conjugation procedure, information is restored;

They recover information on the basis of calculated and selected eigenvectors that have passed the complex conjugation procedure by the matrix or elementwise method.

The above method allows you to restore information from a received signal generated by the method specified in claim 1.

3. The following characteristic features have been introduced into the signal conditioning apparatus: it contains a block of eigenvectors, a control unit, and an operation unit that perform the actions of claim 1;

The above device allows you to generate a signal in the manner specified in paragraph 1.

4. The following characteristic features are introduced into the device for recovering information from a received signal: it contains a block of eigenvectors, a control unit, and an operation unit that perform the actions of claim 2;

The above device allows you to recover information from a received signal generated by the method specified in claim 1.

Thus, the claimed group of inventions provides a low level of out-of-band emission of communication signals.

The low level of out-of-band radiation, in turn, provides a reduction in inter-channel interference.

The method of signal generation allows the calculation of the elements of the subband matrix for the sum of the used frequency ranges or for the total specified frequency range from which unused frequency ranges are excluded. This feature is relevant in the presence of interference in the communication channel or occupied frequency ranges. The information recovery method according to claim 2 allows you to restore information from signals generated by the specified method. The low level of out-of-band radiation and the possibility of excluding frequency ranges from the used frequency band can improve the noise immunity of communication.

Saving in the memory of the device (information carrier) of the pre-calculated and selected eigenvectors of the subband matrix for the given frequency ranges can reduce the number of computational operations, reduce the performance requirements of the computing resources of the devices, and at the same time increase the speed of signal generation / reconstruction.

The signal generation in this way allows you to reduce the protective frequency intervals, so you can increase the amount of useful information transmitted over the same period of time - i.e. transfer rate of useful information.

The invention is illustrated by the images presented in figures 1-7.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 - Scheme of the prototype;

Designations:

101 - input data;

102 - buffer conversion serial code to parallel;

103 - multicarrier modulator block (inverse DFT);

104 - adding a cyclic prefix and parallel-serial conversion;

105 - digital-to-analog converter.

111 - analog-to-digital Converter;

112 - block removal of a cyclic prefix and sequentially - parallel conversion;

113 - block demodulator on many carriers (DFT);

114 - parallel - serial converter;

115 - digital stream.

Figure 2 - Diagram of an embodiment of a transmitter with a signal conditioning device

101 - input data; 102 - buffer conversion serial code to parallel;

203 — a signal conditioning apparatus;

204 —a block for optionally adding a guard interval and parallel-serial conversion;

105 - digital-to-analog converter.

In Fig.Z is a diagram of an embodiment of a receiver with a device for recovering information from a received signal

Designations:

111 - analog-to-digital Converter;

212 - block optional removal of the guard interval and serial-parallel conversion;

213 - information recovery device;

114 - parallel - serial converter;

115 - digital stream.

Figure 4 - Diagram of a signal conditioning device

Designations:

203 — a signal conditioning apparatus;

301 - control unit;

302 — block of eigenvectors (signal conditioning apparatus);

3021 - eigenvector generator;

3022 - information carrier;

305 operational unit;

5 is a diagram of a device for recovering information from a received signal

Designations:

213 - information recovery device;

301 - control unit;

312 - block of eigenvectors (device for recovering information from a received signal);

3121 - shaper of eigenvectors;

3022 - information carrier;

315 operational unit;

/ In FIG. 6 - energy spectra of channel signals generated by various methods.

a) The energy spectrum of the channel signal generated using the basis of the eigenvectors of the subband matrix;

b) The energy spectrum of the channel signal generated using the basis

Fourier.

In FIG. 7 - energy spectra of channel signals with freed specified frequency ranges generated by various methods.

b) The energy spectrum of the channel signal generated using the Fourier basis.

DETAILED DESCRIPTION OF THE INVENTION

1. The proposed method of signal formation, characterized in that:

elements of the subband matrix are calculated for given frequency ranges C = {c _d }, ί, k = 1, ..., N using one of the methods:

1) by calculating the elements of the subband matrix for the sum of the specified frequency ranges, according to an expression of the form:

e - exhibitor;

U \ u _{2 t - t is} the bandwidth of the used frequency range t; lower and upper limits of the used frequency

- allowable area for the lower and upper boundaries, used frequency ranges, G c; M the total number of used frequency ranges;

t is the number of the used frequency range;

j imaginary unit;

c - subband matrix elements for given frequency ranges;

i, k are natural numbers from 1 to N;

N = F -T _{b - the} size of the matrix and the number of samples;

F sampling frequency in Hz;

T _{b - the} duration of the character in seconds.

2) by calculating the elements of the subband matrix for a common predetermined frequency range from which unused frequency ranges are excluded, according to an expression of the form:

where G = e jV, (ik) jV ₂ (ik e is the exponent;

W w

V _x = mc—, V = m - the upper and lower boundaries of a given frequency range;

F f

AV = \ V - T _i | - width of a given frequency band;

W is the width of a given frequency band in Hz, G <F;

F sampling frequency in Hz;

excluded range h, g = 0;

e is the exponent;

P = \ ^vv \ bandwidth of the excluded frequency range h, p = 0; lower and upper bounds of the excluded frequency

the area for the lower and upper boundaries of the excluded frequency ranges, G c; B is the total number of excluded frequency ranges, if B = 0 there are no excluded frequency ranges, then the signal occupies the entire selected frequency range;

h is the number of the excluded frequency range;

j is the imaginary unit;

c _{ik -} subband matrix elements for given frequency ranges;

i, k are natural numbers from 1 to N;

N = F - T _{b - the} size of the matrix and the number of samples;

T _{b - the} duration of the character in seconds.

form a set of eigenvalues and the corresponding set of eigenvectors q of the subband matrix C, calculated for given frequency ranges, where:

^~ eigenvector column of the subband matrix

C = {c _ik }, i, k = -, N

where N is the size of the matrix and the number of samples

T - transpose sign

i, k are natural numbers from 1 to N

- based on the eigenvalues of the corresponding eigenvectors of the subband matrix, J eigenvectors are sampled in accordance with the specified transmission parameters, the eigenvalues of which are close to unity. The subband matrix is calculated for given frequency ranges;

- on the basis of the calculated and selected eigenvectors form a signal using one of the methods:

1) Elementally - by summing the products of each symbol of the information channel to the elements of the corresponding selected eigenvector:

x = (xx ₂ , ..., x _N )

ha-1

Where:

x is a signal generated on the basis of a subband matrix for given frequency ranges; x _t is the element of the generated signal;

C [ _{in is} the ith element of the eigen column vector for the hth information symbol;

e _{p is an} information symbol;

n is the number of the information symbol, a natural number from 1 to J;

i is the number of the vector element, a natural number from 1 to N;

J is the number of eigenvectors used, the number of information symbols;

2) Matrix - by the product of the orthogonal basis in the form of a matrix consisting of selected eigenvectors-columns of the subband matrix and the column-vector of information symbols coming from the information channels: x = Q · e, while the condition: Q ^H - Q ~ E

Where:

x is a signal generated on the basis of a subband matrix for given frequency ranges;

· · ']) - an orthogonal basis, which is a matrix consisting of a selected set of eigenvectors-columns of a subband matrix;

q = {qi, q ₂ , ..., q _N ^ j is an eigen column vector consisting of N samples;

T is the sign of transposition;

e = (e, e ₂ , ..., e _y ) ^r is the column vector of the transmitted information symbols;

Q ^H - conjugate-transposed orthogonal basis;

E is the identity matrix;

N is the number of samples, the dimension of the vector;

- when performing a matrix operation, a parallel-serial signal conversion is performed;

- if necessary, add a protective interval to the beginning of the symbol, in the form of a passive pause or other information without breaking the phase between the symbol and the protective interval;

For wireless communication systems, operations known in the art are performed: convert the signal into analog form using a digital-to-analog converter;

transmit a signal using a quadrature modulator and a transmitting antenna. The calculated and selected eigenvectors of the subband matrix for given frequency ranges can be stored in the memory of the device (storage medium) for later use.

The above method of signal generation is implemented at the hardware level as follows (see Fig. 2 and Fig. 4):

The transmitted information stream enters the buffer 102 for serial-parallel conversion, after which the signal enters the signal generating unit 203, where the signal is generated based on the eigenvectors of the subband matrix for the given frequency ranges, according to the above method.

In the signal generating unit 203, information for calculating and selecting eigenvectors of the subband matrix for given frequency ranges, including a method for calculating the elements of the subband matrix, is received from the control unit 301. In an alternative embodiment of the claimed solution, the initial parameters for calculating the elements of the subband matrix, such as the bandwidth , lower and upper bounds of frequency ranges, sampling frequency, symbol duration, matrix size and number of samples and other derivatives or dependent parameters The frames can be specified in the signal conditioning unit 203 initially or calculated based on the specified parameters. Calculation options are presented below.

Accordingly, if the method of calculating the elements of the subband matrix for the sum of the specified frequency ranges is used, then information on the total number of used frequency ranges (M) is supplied to the eigenvector 3021 of the eigenvector block 302; the lower and upper boundaries of each of the used frequency ranges (V _im V _2m ) having the number (t); sampling rate in Hz (F); character duration in seconds (7),). The acceptable area for the lower and upper boundaries of the used frequency ranges is determined depending on the sampling frequency (F). Based on the values of the sampling frequency in Hz (F) and the symbol duration in seconds (1),), the matrix size and the number of samples (N) are determined in the eigenvector 3021. Based on values the lower and upper boundaries of each used frequency band ^_(ΐ? i _{^ϊ? ϊ ί} having the number (x) determine the bandwidth used frequency range m. On the basis of the values used frequency ranges in the shaper eigenvectors 3021 calculated elements of the subband of the matrix, taking into account the size of the matrix and the number of samples (N).

If the method of calculating the elements of the subband matrix is used for a common predetermined frequency range from which unused frequency ranges are excluded, then the eigenvector 3021 of the eigenvector block 302 receives information about the width of the given frequency band in Hz (1 D or the upper and lower boundary of the given frequency range (G. 1); lower and upper bounds of each excluded frequency range u _ih, u _2h having number h; sampling rate in

Hz () the total number of excluded frequency ranges (V); character duration in seconds (T _b ). The permissible region for the lower and upper boundaries of the excluded frequency ranges is determined depending on the width of the specified frequency band (W). Based on the sampling frequency in Hz (F) and the symbol duration in seconds (7 ^), the matrix size and the number of samples (N) are determined in the eigenvector 3021.

Based on information about the upper and lower boundaries of a given frequency range (1, G.) and sampling frequency (F), the width of a given frequency band (W) is determined, and based on the values of the lower and upper boundaries of each excluded frequency range u _IL, v _lh and sampling frequency (F) determines the bandwidth of each excluded frequency range p _h .

Based on the values of the given frequency band and the excluded ranges, the elements of the subband matrix are calculated in the eigenvector 3021.

Further, in the eigenvector 3021, a set of eigenvalues and a corresponding set of eigenvectors q are formed, which are eigenvector columns of the subband matrix C calculated for given frequency ranges. Further, based on the eigenvalues of the corresponding eigenvectors of the subband matrix, in the eigenvector 3021, J eigenvectors are sampled in accordance with the specified transmission parameters, the eigenvalues of which are close to unity.

Pre-calculated and selected eigenvectors of the subband matrix for given frequency ranges can be stored in the device memory (block 3022) for later use. Information about the number and order of use of the stored eigenvectors comes from the control unit 301.

Further, from the corresponding outputs of the eigenvector block 302, the signal is supplied to one of the inputs of the operation unit 305, and to its other inputs, a signal is received containing the transmitted information, where the signal is generated on the basis of the calculated and selected eigenvectors using one of the methods:

a) Elementally - by summing the products of each symbol of the information channel into the elements of the corresponding selected eigenvector; b) Matrix - by the product of the orthogonal basis in the form of a matrix consisting of selected eigenvectors-columns of the subband matrix by a vector-column of information symbols coming from information channels.

The result from block 203 is fed to block 204, where a parallel-serial conversion is performed (for matrix operations) and, if necessary, a guard interval is added. Next, the signal is fed to a digital-to-analog converter 105 for further broadcasting using a modulator (not shown in the diagram).

Thus, since the signal is formed on the basis of the eigenvectors of the subband matrix for the given frequency ranges, a low level of out-of-band radiation is achieved, resulting in a decrease in inter-channel interference and improved noise immunity of the communication, as well as the possibility of excluding frequency ranges from the used frequency band. Saving in the memory of the device (information carrier) of the pre-calculated and selected eigenvectors of the subband matrix for the given frequency ranges can reduce the number of computational operations, reduce the performance requirements of the computing resources of the devices, and at the same time increase the speed of signal generation / reconstruction. Signal generation in the specified way, allows you to reduce the protective frequency intervals, so you can increase the amount of transmitted useful information for the same period of time - i.e. transfer rate of useful information.

2. The proposed method for recovering transmitted information is characterized in that:

calculate the elements of the subband matrix for the given frequency ranges C = {s _. }, i, k = 1, ..., N using one of the methods:

e - exhibitor;

and _m = \ ^and 2 _m ^{~ v} \ m \ the bandwidth of the used frequency range m; u _l = Ίp f, u ₂ = 2p f ² ^ ^. _ lower and upper limits of the used frequency

F f

range;

- allowable area for the lower and upper boundaries, used frequency ranges, G c;

M is the total number of used frequency ranges;

t is the number of the used frequency range;

j is the imaginary unit;

c _{ik -} subband matrix elements for given frequency ranges;

i, k are natural numbers from 1 to N;

N = F -T _{b - the} size of the matrix and the number of samples;

F is the sampling frequency in Hz;

T _{b - the} duration of the character in seconds.

e is the exponent;

W w

V _x = —it—, V ₂ = mc - the upper and lower boundaries of a given frequency range;

AV = \ V _{2 -} V | - width of a given frequency band;

W is the width of a given frequency band in G C, W <F;

F is the sampling frequency in Hz;

excluded range h, g ₀ = 0;

e - exhibitor;

P _n = \ ^v _2h ^v _{\ h} \ bandwidth of the excluded frequency range h, p ₀ = 0; lower and upper bounds of the excluded frequency

h range

fi _h> fi _h ^G [- W / 2, w / 2] f _lh - <f _{2h -} region for the lower and upper boundaries of the excluded frequency ranges, G c;

B is the total number of excluded frequency ranges, if B = 0 there are no excluded frequency ranges, then the signal occupies the entire selected frequency range;

h is the number of the excluded frequency range;

j is the imaginary unit;

c _{ik -} subband matrix elements for given frequency ranges;

i, k are natural numbers from 1 to N;

N = F - T _{b - the} size of the matrix and the number of samples;

T _{b - the} duration of the character in seconds.

- form, a set of eigenvalues and the corresponding set of eigenvectors of the subband matrix C, calculated for given frequency ranges, where: H = \ I ₁ , q ₂ , ..., q _N ) is the eigenvector column of the subband matrix

N is the size of the matrix and the number of samples;

G is the sign of transposition;

i, k - natural numbers from 1 to N;

- based on the eigenvalues of the corresponding eigenvectors of the subband matrix, select J eigenvectors, in accordance with the specified transmission parameters, identical to the eigenvectors on the transmitting side;

- based on the calculated and selected eigenvectors, information is restored using one of the methods:

1) Elementally - by summing, over the duration of the information symbol, the results of the product of complex conjugate elements of the corresponding eigenvector of the subband matrix by the elements of the digitized signal from the communication channel without a guard interval:

r = (r ₁ , r ₂ , ..., r _J ), where:

r _{n is the} received n-th information symbol; q _{in is the} i-th complex conjugate element of the eigen column vector for the fifth information symbol;

s is the z-th element of the digitized channel signal;

i - element number, natural number from 1 to N;

n is the number of the information symbol, a natural number from 1 to J;

J is the number of eigenvectors used, the number of information symbols;

* - sign of complex conjugation;

2) Matrix - by producing a conjugate-transposed orthogonal basis on a column vector of elements from a communication channel, without a guard interval (when performing a matrix operation, values from an analog-to-digital converter for serial-parallel conversion are accumulated in the buffer): g = Q ^H · S, the condition is satisfied: Q ^H - Q ~ E, where:

g is the vector of received information; Q ^H - conjugate-transposed orthogonal basis;

H - Hermitian conjugation or conjugate-transpose;

S = ( _Sl , s ₂ , ..., sJ is the column vector of the elements from the communication channel, without a guard interval;

T is the sign of transposition;

Q = q _v q ₂ , ..., q _j ) is the orthogonal basis, which is a matrix consisting of a selected set of eigenvectors-columns of the subband matrix;

q = {<h, q ₂ , ..., q _N ^ j is an eigen column vector consisting of N samples;

E is the identity matrix;

Complex conjugate, calculated and selected eigenvectors of the subband matrix for given frequency ranges can be stored in the device memory (storage medium) for later use.

A method of recovering transmitted information from a received signal at the hardware level is as follows (see Fig. 3 and Fig. 5):

To restore information from a signal received by a wireless method, operations known from the prior art are performed:

A signal is received through a receiving antenna and fed to a quadrature demodulator, from where it is fed to an analog-to-digital converter 111, which digitizes the signal. The digitized signal is input to the block 212 in series-parallel conversion and removal of the guard interval, where the guard interval, if any, is removed and the signal is transmitted further to the inputs of the information recovery block 213.

Further, according to the claimed group of inventions, in the information recovery unit 213, information for calculating and selecting eigenvectors of the subband matrix for given frequency ranges, including a method for calculating elements of the subband matrix, is received from the control unit 301 to the eigenvector block 312.

In the eigenvector 3121 of the eigenvector block 312, the elements of the subband matrix are calculated for the given frequency ranges in the same way as the block 3021 of the eigenvector block 302.

Further, in the eigenvector 3121, a set of eigenvalues and a corresponding set of eigenvectors q, which are own vector columns of the subband matrix C, calculated for given frequency ranges.

Further, based on the eigenvalues of the corresponding eigenvectors of the subband matrix, in the eigenvector 3121, J eigenvectors are sampled in accordance with the specified transmission parameters identical to the eigenvectors on the transmitting side. Produce a complex conjugation of each element of the selected vectors.

The complex conjugate, calculated and selected eigenvectors of the subband matrix for given frequency ranges can be stored in the device memory (block 3022) for later use. Information about the number and order of use of the stored eigenvectors comes from the control unit 301.

Further, from the outputs of block 312, the signal is supplied to one of the inputs of operational block 315, and the signal from the corresponding outputs of block 212 is received at other inputs, where, based on the calculated and selected eigenvectors, information is restored using one of the methods:

a) Elementally - by summing, over the duration of the information symbol, the results of the product of complex conjugate elements of the selected corresponding eigenvector of the subband matrix by the elements of the digitized signal from the communication channel without a guard interval.

b) Matrix - by producing a conjugate-transposed orthogonal basis on a column vector of elements from a communication channel, without a guard interval (when performing a matrix operation, values from an analog-to-digital converter for serial-parallel conversion are accumulated in the buffer).

The result from block 213 is fed to block 114 in parallel-serial conversion, the output of which gives a transmitted digital stream for further processing.

Thus, since the signal is restored on the basis of the eigenvectors of the subband matrix for the given frequency ranges, a low level of out-of-band radiation is achieved, resulting in a decrease in inter-channel interference and improved noise immunity of the communication, as well as the possibility of excluding frequency ranges from the used frequency band. Saving in memory devices (information carrier) of pre-calculated, selected and complex conjugate eigenvectors of the subband matrix for given frequency ranges can reduce the number of computational operations, reduce the performance requirements of the computing resources of devices, while increasing the speed of signal recovery.

Methods of generating a signal and recovering information from a received signal can be implemented on hardware or software, or any combination thereof. This invention is not limited to its use for structural elements and circuit diagrams of components set forth in the following description or illustrated in the drawings. The invention allows other implementations before and after the operation of generating a signal and restoring information based on the eigenvectors of the subband matrix and can be carried out or performed in other ways. The invention and its parts can be implemented on a single device or separately. Also, the phraseology and terminology used here are for description and should not be construed as limiting.

3. Implementing a signal conditioning method, a signal conditioning apparatus, (FIG. 2, FIG. 4), comprises a block of eigenvectors, a control unit and an operation unit.

The block of eigenvectors 302, allows you to create a basis for generating a signal based on eigenvectors, in accordance with the proposed method. Block 302 may contain an eigenvector 3021 that performs eigenvector calculations, and a storage medium 3022, in which the calculation results are written, or only one of them. If there is only a shaper of eigenvectors 3021, calculations of eigenvectors are performed continuously. If there is only a storage medium 3022, the results of pre-calculated calculations of eigenvectors that are used in the formation of the signal are recorded on it.

The control unit 301 controls the block of eigenvectors 302. The operation unit 305 performs the operations of multiplication and addition and can be implemented in the following options:

1) For the element-by-element formation: block 305 contains J multipliers, the input of which receives the corresponding information symbols, and the elements of the corresponding eigenvectors arrive at the other inputs orthogonal basis. The outputs of the multipliers are connected to a common adder, where the results of the product of the elements of the corresponding eigenvector by the information symbol are summed.

2) For matrix formation: block 305 contains an element of matrix multiplication by a vector, one input of which receives a vector of information elements, and another input receives an orthogonal basis in the form of a matrix, consisting of selected eigenvectors of a subband matrix calculated for given frequency ranges.

For transmitting information, a transmitter may be used, including: a serial to parallel conversion buffer 102, the outputs of which are appropriately connected to the inputs of the signal conditioning instrument 203, which is connected to the optional guard interval and parallel-serial conversion unit 204. Block 204 is connected to a block of digital-to-analog converter 105, which is connected to a quadrature modulator (not shown in the diagram).

The operation of the transmitter with the signal conditioning device at the hardware level is as follows:

The transmitted information stream enters the buffer 102 for serial-parallel conversion, after which the signal enters the signal conditioning instrument 203, where the signal is generated based on the eigenvectors of the subband matrix for the given frequency ranges, according to the above method: J vectors corresponding to the given parameters are selected and satisfying the condition of the values of the corresponding eigenvalues of each eigenvector; calculation and storage of vectors is carried out by a block 302 of eigenvectors for given frequency ranges, which is controlled by a control unit 301; from the corresponding outputs of the eigenvector block 302, the signal is supplied to one of the inputs of the operation unit 305, and to its other inputs, a signal is received containing the transmitted information. The result from block 203 is fed to block 204, where, if necessary, a guard interval is added and / or parallel-serial conversion is performed. Next, the signal is fed to a digital-to-analog converter 105 for further broadcasting using a modulator (not shown in the diagram). Fig.6 and Fig.7 presents the energy spectra of channel signals generated by the classical OFDM method using the Fourier basis, and the spectra of channel signals generated by the method proposed in this invention. As can be seen in the figures, the proposed method allows to obtain a lower level of out-of-band emission of signals (-170 dB. Vs. -25dB), Thus, the claimed technical result is achieved.

4. Implementing a method of recovering information, a device for recovering information from a received signal, (FIG. 3, FIG. 5), comprises an eigenvector block, a control unit and an operation unit.

The block of eigenvectors 312 allows you to create a basis for restoring information from received signals, as well as perform complex conjugation of the matrix with transposition, in accordance with the proposed method. Block 312 may comprise an eigenvector generator 3121 that performs eigenvector calculations and complex conjugation of matrix elements, as well as transposes this matrix for a matrix operation, and an information carrier 3022, in which the calculation results are written, or only one of them. If there is only a shaper of eigenvectors 3121, the calculations are performed continuously. If there is only information carrier 3022, the results of pre-calculated calculations of eigenvectors and complex conjugation of matrix elements with transposition of this matrix, which are used in signal reconstruction, are recorded on it.

The control unit 301 controls the block of eigenvectors 312. The operation unit 315 performs operations of multiplication and addition and can be implemented in the following options:

1) For element-by-element recovery: block 315 contains J multipliers, one inputs of each of which receive elements from the communication channel, and the other inputs receive complex conjugate elements of the corresponding selected eigenvectors. Each of the outputs of the multipliers is connected to the corresponding input of one of the J adders (integrators), where the summation is carried out, with the accumulation of the results of the multiplication over the duration of one symbol, after which the result is reset.

2) For matrix reconstruction: block 315 contains a multiplication element, the conjugate-transposed orthogonal basis arrives at one input, and at the other input, a column vector of elements from the communication channel is received, without a guard interval.

To receive information wirelessly, a receiver can be used, including: a receiving antenna with a quadrature demodulator (not indicated), the output of which is connected to the input of the analog-to-digital converter 111, which is connected to the block 212 optional removal of the protective interval and serial-parallel conversion, the outputs of which are connected with information recovery unit 213, the outputs of each channel of which are connected to parallel-serial converter unit 114, from which the generated circuit Frova stream 115 is fed to further processing. Character detectors for recovering bit information can be used both before and after block 114, depending on the communication system, such a permutation does not affect the receipt of a technical result.

The operation of the receiver with the device for recovering information from the received signal is as follows: the received signal through the receiving antenna and the quadrature demodulator is fed to an analog-to-digital converter 111, which digitizes the signal. The digitized signal is input to the block 212 in parallel-parallel conversion and removal of the protective interval, where the protective insert, if any, is removed and the signal is transmitted further to the inputs of the information recovery device 213, where:

- In block 312, the formation and / or storage of a set of eigenvectors of the subband matrix is performed, according to the above method — the selected and generated orthogonal basis must be identical to the orthogonal basis on the transmitting side. Block 301 controls block 312. The eigenvector block 312 also performs complex conjugation and transposition of the calculated eigenvector matrix in block 3121 and / or stores the conjugate-transposed eigenvector matrix in block 3022.

- Further, from the outputs of block 312, the signals are sent to one input of the operating unit 315, and signals from the corresponding outputs of block 212 are received at the other inputs, where the complex conjugate and transposed matrix of eigenvectors are multiplied by the vector of the received digitized signal. With the element-wise multiplication procedure, the digitized signal from the communication channel is fed to one input multipliers of the operating unit, and complex-conjugate elements of the corresponding eigenvectors are fed to other inputs. Multiplication results are summed over the duration of the character.

The result from the information recovery device 213 is supplied to the parallel-serial conversion unit 114, at the output of which we obtain a transmitted digital stream for further processing.

If the signal conditioning device and the device for recovering information from the received signal are implemented on the same platform, then the block 302 and the block 312 can be combined, while the function of complex conjugation and / or transposition for the device for recovering information from the received signals is performed in a separate block.

In various embodiments of the invention, the eigenvector blocks 302 and 312 comprise either an eigenvector 3021/3121, or a storage medium 3022, or both at the same time. Various embodiments of blocks 302 and 312 do not affect the operation of signal conditioning and information recovery devices.

Calculations of the eigenvectors of the subband matrix and complex conjugation of the matrix with transposition can be performed on another device, for subsequent recording of the results on the storage medium 3022 and their use in signal generation and information recovery.

The storage medium 3022 may be read-only memory (ROM) or a hard disk or a solid-state drive or flash memory or optical disk or hybrid drives or random access memory (RAM) or a remote computer system or remote data storage.

These functional blocks of devices can be implemented on FPGA (Programmable Logic Integrated Circuit) and / or SoC (System on a Chip), executed in the firmware in such a way as to carry out the functions prescribed by him above.

The present detailed description is made up of various non-limiting and exhaustive embodiments. At the same time, it will be apparent to those skilled in the art with a medium level of competence that various substitutions, modifications, or combinations of any of the embodiments disclosed herein (including in part) may be reproduced within the scope of the present invention. Thus, it is understood and understood that the present description of the invention includes additional embodiments, the essence of which is not set forth here in an explicit form. Such embodiments may be obtained, for example, by combining, modifying, or transforming any actions, components, elements, properties, aspects, characteristics, limitations, etc., related to the embodiments presented herein and not being restrictive.

REFERENCES

1. OFDMA access based on cognitive radio. Patent for invention N ° 2446603. Registered in the State Register of Inventions of the Russian Federation 03/27/2012. Authors: Hassan A.A., Hutem K.; Applicant and patent holder of Microsoft Corporation.

2. Variable coding and modulation of the orthogonal frequency division multiplexing subchannel. Patent for invention N ° 2433555. Registered in the State Register of Inventions of the Russian Federation on 10.11.2011. Authors: Abhishek A., Hassan A. A., Huytema K., U Deyun, Cuenel T .; Applicant and patent holder of Microsoft Corporation.

3. Adaptation of the data transfer rate in the OFDM - system in the presence of interference. Patent for invention N ° 2344546. It is registered in the State Register of Inventions of the Russian Federation on January 20, 2009. Authors: Goncharov E.V .; Applicant and Patent Holder Samsung Electronics Co., Ltd.

4. IEEE Std P802 L 6-2004, NEX Standart for Local and metropolitan area networks - Part 16: Air Interface for Fixed BWA Systems.

Claims

CLAIM

1. The method of signal formation, characterized in that:

- calculate the elements of the subband matrix for the given frequency ranges;

2. The method according to claim 1, characterized in that the elements of the subband matrix are calculated for the sum of the used frequency ranges.

3. The method according to claim 1, characterized in that the elements of the subband matrix are calculated for a common predetermined frequency range from which unused frequency ranges are excluded.

4. The method according to claim 1, characterized in that the signal is formed on the basis of calculated and selected eigenvectors by the matrix method.

5. The method according to claim 1, characterized in that the signal is formed on the basis of calculated and selected eigenvectors by the elementwise method.

6. The method according to claim 1, characterized in that the pre-calculated and selected eigenvectors of the subband matrix for the given frequency ranges are stored in the memory of the device (storage medium).

7. A method of recovering transmitted information, characterized in that:

- calculate the elements of the subband matrix for the given frequency ranges;

- based on the calculated and selected eigenvectors that have passed the complex conjugation procedure, information is restored.

8. The method according to claim 7, characterized in that, recover information based on the calculated and selected eigenvectors that have passed the complex conjugation procedure, the matrix method.

9. The method according to claim 7, characterized in that, recover information based on the calculated and selected eigenvectors that have passed the complex conjugation procedure, element-by-element method.

10. The method according to claim 7, characterized in that the pre-calculated and selected eigenvectors of the subband matrix for the given frequency ranges are stored in the device memory (storage medium).

11. The signal conditioning apparatus, characterized in that it contains a block of eigenvectors, a control unit and an operation unit that perform the actions according to claim 1.

12. The device according to claim 11, characterized in that the operating unit performs operations by a matrix method.

13. The device according to claim 11, characterized in that the operating unit performs operations by the element-wise method.

14. A device for recovering information from a received signal, characterized in that it contains a block of eigenvectors, a control unit and an operation unit performing the steps of claim 7.

15. The device according to 14, characterized in that the operating unit performs operations matrix method.

16. The device according to 14, characterized in that the operating unit performs operations by the element-wise method.