CN117676561A - Cognitive radio signal safe transmission method based on overlay and underly - Google Patents

Cognitive radio signal safe transmission method based on overlay and underly Download PDF

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Publication number
CN117676561A
CN117676561A CN202311682877.9A CN202311682877A CN117676561A CN 117676561 A CN117676561 A CN 117676561A CN 202311682877 A CN202311682877 A CN 202311682877A CN 117676561 A CN117676561 A CN 117676561A
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overlay
key
underlay
waveform
representing
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司光振
刘建
杨健
苏焕程
王洪斌
高路
张俊
史成卓
刘泳伶
吕方晖
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8511 Research Institute of CASIC
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8511 Research Institute of CASIC
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Abstract

The invention discloses a cognitive radio signal safety transmission method based on overlay and underlay, and belongs to the field of cognitive radio communication. The method comprises the following steps: the SMSE model allocates subcarriers, modulates, encodes, and uses windowing functions to generate overlay and underlay cognitive radio waveforms. And respectively loading the encrypted bit stream and the corresponding key through an overlay waveform and an underlay waveform by adopting an encryption technology and a key splicing mechanism, and transmitting the overlay and underlay aliasing waveforms through an antenna. At the receiving end, the key is used for decrypting the received encrypted information after a series of inverse transformation, and the original information is recovered. On the basis that the SMSE model generates overlay and underlay waveforms to transmit encryption information, a key splicing mechanism is adopted, so that error code performance under secure communication can be improved, and the method has the advantage of concealing the secure communication.

Description

Cognitive radio signal safe transmission method based on overlay and underly
Technical Field
The invention belongs to the field of cognitive radio communication, and particularly relates to a cognitive radio signal safety transmission method based on overlay and underlay.
Background
Spectrum access modes in cognitive radio can be divided into: opportunistic (overlay) access and substrate (underlay) access. The overlay access mode is that the cognitive user accesses to a frequency band which is not used by the main user to use the frequency band, and the underly access mode is that the cognitive user accesses to the frequency band which is used by the main user to use the frequency band. Cognitive radio waveforms with better transmission performance to adapt to surrounding spectrum changes can be conveniently and flexibly generated through overlay and underly.
The cognitive radio communication system is also provided with safety and concealment besides ensuring effective transmission of information. Encryption is an effective means adopted for ensuring information security, and by using an encryption mechanism, an information sequence (namely a plaintext) is scrambled, then the information is sent and transmitted, and a corresponding inverse process is adopted at a receiving end, so that the encrypted information is restored to the original information, namely decrypted to the plaintext.
The cognitive radio communication system has important research significance in researching the cognitive radio signal safety transmission method based on overlay and underlay in order to reduce the risk of information theft or spoofing when an illegal user steals electromagnetic data from a channel or transmits false information in the channel.
Disclosure of Invention
Aiming at the capability of a cognitive radio communication system for improving the safety communication, the invention provides a cognitive radio signal safety transmission method based on overlay and underlay, which utilizes an SMSE mathematical model to generate overlay waveforms and underlay waveforms and then applies the overlay and underlay to encrypted communication. .
The technical scheme for realizing the invention is as follows: the security transmission method of the cognitive radio signal based on the overlay and the underlay is characterized in that the overlay and the underlay process the signal bit stream in a division mode under spectrum access, and the security transmission method comprises the following steps:
step 1, before transmission, encrypting original information data to be transmitted by using a secret key to generate an encrypted bit stream; numbering and indexing the radio communication nodes, splitting the secret key into M sections according to a protocol, wherein M is the number of the underley cognitive nodes; and (3) the cognitive node performs spectrum access by using an overlay mode and an underley mode according to the sensing result, and simultaneously, the cognitive node shifts to the step (2) and the step (3).
And 2, at a transmitting end, generating an overlay waveform by using an SMSE model, and turning to step 4.
And step 3, generating an underley waveform by using an SMSE model at a transmitting end, and turning to step 4.
And 4, carrying out frequency domain addition on the overlay waveform and the underley waveform at a transmitting end, carrying out up-conversion by using IFFT operation to generate overlay and underley time domain waveforms, transmitting, and turning to the step 5.
And 5, receiving the overlapping and underlay full frequency band by the receiving end, converting the time domain signal into a frequency domain signal through down-conversion, serial-parallel conversion and FFT conversion, performing baseband demodulation and decoding processing on the frequency domain signal, recovering the data transmitted by the transmitting end, namely, encrypting the bit stream, and turning to the step 6.
And 6, after the key is spliced, the encrypted bit stream is decrypted, the encryption data on the received overlay waveform is decrypted by using the key on the received underley waveform, and the original information data is recovered.
Compared with the prior art, the invention has the remarkable advantages that:
1) And generating an overlay waveform by using an SMSE model to transmit the encrypted bit stream, generating an underley waveform by using an SMSE framework to transmit a corresponding key, and ensuring communication safety while flexibly using a frequency spectrum.
2) On the basis that the SMSE model generates overlay waveforms and underley waveforms to carry out information transmission, a key splicing mechanism is provided, and error code performance under safety communication can be improved.
Drawings
Fig. 1 is a block diagram of an overlay and underly based radio signal transmission.
Fig. 2 is a radio signal reception block diagram based on overlay and underlay.
Fig. 3 shows spectrum access during security transmission of overlay and underlay, where (a) is the spectrum distribution diagram of overlay and primary users, and (b) is the spectrum distribution diagram of underlay and primary users.
Fig. 4 shows the bit error rate comparison for different transmission methods.
Fig. 5 is an original image before encryption at the transmitting end.
Fig. 6 is an overlay receiver image result.
Fig. 7 is a receiving end image result based on overlay and underlay secure transmission, where (a) is a receiving result when snr=6 dB, and (b) is a receiving result when snr=12 dB.
Fig. 8 is a schematic block diagram of a cognitive radio signal secure transmission method based on overlay and underlay according to the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by one of ordinary skill in the art without creative efforts, are within the scope of the present invention based on the embodiments of the present invention.
The technical solutions of the embodiments of the present invention may be combined with each other, but it is necessary to base the implementation of those skilled in the art, and when the technical solutions are contradictory or cannot be implemented, it should be considered that the combination of the technical solutions does not exist, and is not within the scope of protection claimed by the present invention.
The following describes the specific embodiments, technical difficulties and inventions of the present invention in further detail in connection with the present design examples.
The invention provides a cognitive radio safety transmission method based on overlay and underlay, which is used for jointly applying overlay and underlay to hidden communication and can reduce the risk of information theft or spoofing. By using the SMSE model to configure waveform design parameters, flexible generation of overlay and underley waveforms is realized. And then, a key splicing mechanism is provided, a plurality of underlay nodes transmit corresponding keys by using underlay waveforms, the encrypted bit stream is transmitted by using overlay waveforms, and the overlay waveforms and the underlay waveforms are jointly deployed to transmit information. At the receiving end, the transmitting end is recovered to transmit data through the processes opposite to the transmitting end, namely down conversion, serial-parallel conversion, FFT conversion, baseband demodulation and decoding, and finally, the encryption bit stream on the received overlay waveform is decrypted by using the key on the received underley waveform to recover the original information data. The result shows that the method can improve the information security transmission performance.
Referring to fig. 1 to 8, the cognitive radio safety transmission method based on overlay and underlay of the invention comprises the following steps:
and 1, before transmission, encrypting the transmission data by using a secret key to generate a bit stream. And numbering and indexing the radio communication nodes at the transmitting end, splitting the secret key into M sections according to a protocol, and carrying out spectrum access by the coordination node in an overlay and underly mode according to a spectrum sensing result by the number of the cognitive nodes with M being underly cognitive nodes.
And 11, encrypting the original information data by using an Arnold scrambling algorithm. Wherein the scrambling transformation is expressed asWherein x is n And y n And respectively representing the abscissa and the ordinate of the elements in the original information data matrix before scrambling. X is x n+1 And y n+1 And respectively representing the abscissa and the ordinate of the scrambled encryption matrix elements. f (Key) is a function with respect to the Key Key, mod (·) is a function of the remainder, and N represents the number of columns of the original information data matrix.
And step 12, splitting the Key Key based on the number of the underley nodes. Key is innovatively transmitted by M nodes in a joint mode, namely Key= [ Key 1 ,Key 2 ,…,Key M ]。
And 13, performing access allocation on the subcarriers used by the encrypted bit stream by the overlay according to the cognitive perception result, and performing access allocation on the subcarriers used by the key by the underlay according to the cognitive perception result. The access allocation vectors of the overlay, underlay subcarriers are respectively and correspondingly denoted as a, a * I.e.Wherein a is i Is the allocation of the overlay ith subcarrier,/->Is the allocation situation of the ith subcarrier of the underlay, and the value of i is i epsilon {1,2, …, N F }。a i ∈{0,1},/>A value of 0 indicates that the subcarrier is not allocated to a node, and a value of 1 indicates that the subcarrier is allocated.
And 14, accessing the subcarriers used by the encrypted bit stream by the overlay according to the cognitive perception result, and accessing the subcarriers used by the secret key by the underlay according to the cognitive perception result. The usage-labeled variables for overlapping and underley sub-carriers are correspondingly denoted as u, u * I.e.Wherein the value range of the coverage ith subcarrier using the marking variable is u i E {0,1}, the index variable value range of the index for the ith subcarrier of underlay is +.>0 indicates that this subcarrier is not used by the node, and 1 indicates that this subcarrier is used by the node.
And 2, generating an overlay waveform by using the SMSE model at the transmitting end.
Step 21, modulating the encrypted bit stream, the modulated data being represented by d, i.e. from 1 to N F Modulated data of the sub-carriers of (a) are recorded asWherein N is F Is the number of sub-carriers, the range of the value of the data modulated by the ith sub-carrier is +.> Representing the complex domain.
Step 22, encoding the modulated data, the encoding being denoted by c, i.e. from 1 to N F The coding of the modulated data on the subcarriers of (a) is noted as
Step 23, shaping the spectrum of the waveform to be transmitted after encoding by changing the spectrum tap coefficient, and the windowing mode is expressed as
The time domain expression of the kth symbol transmitted on the mth subcarrier in the overlay waveform in step 24 isWherein N is F Representing the number of sub-carriers, j representing the imaginary partRe {.cndot. } represents the operation of taking the real part, a m ,u m ,c m ,d m.k ,w m Respectively representing the mth subcarrier allocation, use, encoding, modulation of the kth symbol, and the windowed amplitude. f (f) m Representing carrier frequency, t n Representing symbol interval +.>Respectively representing the phases at the time of modulation, coding, windowing and orthogonal transformation.
And 3, generating an underley waveform by using the SMSE model at the transmitting end.
Step 31, modulating the key, d for data modulation * Representing, i.e. from 1 to N F Modulated data of the sub-carriers of (a) are recorded as
Step 32, encoding the modulated key data. Wherein, c is used for encoding * Representing, i.e. for a range from 1 to N F The coding of the modulated data on the subcarriers of (a) is noted as
Step 33, shaping the spectrum of the waveform to be transmitted after encoding by changing the tap coefficients of the spectrum, and the windowing mode is expressed as
Step 34, the time domain expression of the kth symbol transmitted on the mth subcarrier in the underley waveform is thatWherein N is F Representing the number of sub-carriers, j representing the imaginary part, re {. Cndot. Is represented by the real part calculation, ++>Respectively and correspondingly represents the m-th subcarrier allocation, use, coding and kthModulation of the symbol and the magnitude of the windowing. />Indicating carrier frequency->Representing symbol interval +.>Respectively representing the phases at the time of modulation, coding, windowing and orthogonal transformation.
And 4, at a transmitting end, adding the frequency domain of the overlay waveform and the underley waveform, and performing up-conversion by using IFFT operation to generate the overlay and underley time domain waveforms for transmitting.
Step 41, creatively superposing the overlay waveform and the M underley waveforms to obtain an aliasing waveform asWherein z represents an underley node variable, and the value of z is {1,2, …, M };
step 42, performing IFFT time domain transformation to obtain the time domain waveforms of overlay and underlay as
Step 5, the receiving end receives the overlay and underlay full frequency band, changes the time domain signal into the frequency domain signal through down-conversion, serial-parallel conversion and FFT conversion, then carries out baseband demodulation and decoding processing on the frequency domain signal, and recovers the data transmitted by the transmitting end, namely the encrypted bit stream;
step 51, the receiving end performs overlapping and underley full-band receiving, and the expression of the received signal isWherein N is u Is the number of all cognitive nodes, < >>Representing a row convolution operation, H k [n]Representing the impulse response of the signal, gamma [ n ]]Is noise, H rf [n]Representing the receiver filter used;
step 52, recovering the data transmitted by the transmitting end through down-conversion, serial-to-parallel conversion, FFT conversion, baseband demodulation and decoding processingWherein f -1 (. Cndot.) represents operations such as baseband demodulation and decoding.
And 6, after the key is spliced, the encrypted bit stream is decrypted, the encryption data on the received overlay waveform is decrypted by using the key on the received underley waveform, and the original information data is recovered.
Step 61, splicing the keys according to a key splicing mechanism. Splice expression isWherein z is 1 ,z 2 ,…z M Representation matrix->Corresponding to the respective number of rows of M underly nodes. f (f) -1 (-) represents operations such as baseband demodulation and decoding;
step 62, useAnd performing decryption processing. Wherein x is n And y n Respectively representing the abscissa and the ordinate of the matrix element before scrambling. X is x n+1 And y n+1 Respectively representing the abscissa and the ordinate of the scrambled matrix element. f (Key) -1 Representing the inverse of the Key Key operation, mod (. Cndot.) is the function of the remainder, N representing the number of columns of the matrix before scrambling. And then decrypting and recovering the received encrypted bit stream by using the spliced Key Key to obtain the original information data.
The invention is described in further detail below with reference to examples:
examples:
according to the invention, the communication bandwidth is 10MHz, the number of subcarriers is 256, 64 subcarriers are used by a main user and an underley, and 192 subcarriers on two sides are used by an overlay. And (3) transmitting the encrypted image by using an overlay waveform, and encrypting the Lena image by using an Arnold scrambling algorithm. The number of the underly nodes is 2, and the underly waveform transmits a key corresponding to the encryption. In this simulation example, the overlay transmits 53248 bits of data, and the secret key used by the underlay is: 0624. both underly and overlay use BPSK mapping, overlay uses OFDM modulation, and underly uses spread spectrum coding. Through the additive Gaussian white noise channel, the transmitted encrypted image data and the secret key are demodulated through the process opposite to the transmitting end, and then the original image is decrypted. Setting the simulation signal-to-noise ratio as follows: 10dB, 20dB. Through simulation experiments, the cognitive radio signal safety transmission method based on overlay and underlay is obtained. With reference to fig. 1 to 8, the specific steps are as follows:
and step 1, before transmission, using a classical Lena image as original information data, and encrypting the original information data by using a secret key, wherein the secret key is 0624. And (3) numbering and indexing the radio communication node at the transmitting end, splitting the key into 2 sections according to a protocol, transmitting 06 by using the underly cognitive node 1, and transmitting 24 by using the underly cognitive node 2. The cognitive node performs spectrum access in a coordinated use coverage and underlay mode according to the spectrum sensing result; the method specifically comprises the following steps:
and 11, encrypting the information by using an Arnold scrambling algorithm, wherein the used secret key is 6809.
And step 12, splitting the Key Key based on the number of the underley nodes. The key is sent jointly by 2 nodes, namely by the underly node 1, 06 and by the underly node 2, 24.
And 13, carrying out access allocation on the subcarriers according to the cognitive sensing result. The intermediate 64 sub-carriers are allocated by the underly, and 192 sub-carriers on two sides are allocated by the overlap for access.
And 14, accessing the sub-carriers according to the cognitive sensing result. The subcarriers allocated by overlay and underlay are all used completely, and there is no case where the allocated subcarriers are not used.
And 2, at a transmitting end, generating an overlay waveform by using an SMSE model. The method specifically comprises the following steps:
and step 21, modulating the encrypted bit stream, namely constellation mapping is carried out on the Lena image data encrypted by using the key 0624, wherein the modulation mode is BPSK.
And step 22, encoding the BPSK modulated data. Wherein, overlay does not adopt coding processing, and c takes all 1 vectors.
Step 23, shaping the spectrum of the waveform by changing the tap coefficient of the spectrum, and using a rectangular window with the tap coefficient of 256 points as 1 in a windowing mode.
Step 24, generating an overlay frequency domain waveform is shown in fig. 3 (a).
And 3, generating an underley waveform by using the SMSE model at the transmitting end. The method specifically comprises the following steps of;
step 31, modulating the key, namely using BPSK;
step 32, coding the constellation mapped transmission data, wherein the underley adopts 64-bit walsh codes:
step 33, shaping the spectrum of the waveform by changing the spectrum tap coefficient, and using a rectangular window in a windowing mode.
Step 34, generating an underley frequency domain waveform is shown in fig. 3 (b).
And 4, at a transmitting end, adding the frequency domain of the overlay waveform and the underley waveform, and performing up-conversion by using IFFT operation to generate the overlay and underley time domain waveforms for transmitting. The method specifically comprises the following steps of;
step 41, overlapping the overlay waveform and the underlay waveform to obtain an overlapping waveform of the overlay waveform and the underlay waveform;
step 42, performing 256-point IFFT time domain transformation, and up-converting to 2GHz to obtain a transmission waveform.
And 5, the receiving end performs overlap and underlay full-band receiving, converts the time domain signal into a frequency domain signal through down-conversion, serial-parallel conversion and FFT conversion, and then performs baseband demodulation and decoding processing on the frequency domain signal to recover the data transmitted by the transmitting end, namely the encrypted bit stream. The method specifically comprises the following steps:
step 51, the receiving end receives the overlay and the underley full frequency bands;
step 52, obtaining a time domain waveform through down-conversion to baseband, serial-parallel conversion and 256-point FFT conversion. The received overlay and underlay waveforms are demodulated using BPSK and underlay is decoded using 64-bit walsh codes.
And step 6, the key is spliced, decryption processing is carried out, the encryption data on the received overlay waveform is decrypted by using the key on the received overlay waveform, and the original information data is recovered. The method specifically comprises the following steps:
step 61, decoding the received data of 2 underley nodes to obtain keys 06 and 24 respectively, and splicing the keys to obtain a key 0624;
step 62, decrypting the received encrypted bit stream by 0624 to recover the original information data by using the key decryption process, see fig. 7.
In summary, the security transmission method based on overlay and underlay cognitive radio signals provided by the invention has lower signal-to-noise ratio under the condition of the same error rate compared with the traditional overlay transmission method, has higher security compared with the traditional overlay transmission, and has the advantage of hidden security communication.

Claims (7)

1. The security transmission method of the cognitive radio signal based on the overlay and the underlay is characterized in that the overlay and the underlay process the signal bit stream in a division mode under spectrum access, and the security transmission method comprises the following steps:
step 1, before transmission, encrypting original information data to be transmitted by using a secret key to generate an encrypted bit stream; numbering and indexing the radio communication nodes, splitting the secret key into M sections according to a protocol, wherein M is the number of the underley cognitive nodes; the cognitive node performs spectrum access by using an overlay mode and an underley mode according to the sensing result, and simultaneously, the cognitive node shifts to the step 2 and the step 3;
step 2, generating an overlay waveform at a transmitting end by using an SMSE model, and turning to step 4;
step 3, generating an underley waveform at a transmitting end by using an SMSE model, and turning to step 4;
step 4, at the transmitting end, adding the frequency domain of the overlay waveform and the underley waveform, performing up-conversion by using IFFT operation to generate overlay and underley time domain waveforms, transmitting again, and turning to step 5;
step 5, receiving the overlapping and underlay full frequency band by the receiving end, converting the time domain signal into a frequency domain signal through down-conversion, serial-parallel conversion and FFT conversion, then carrying out baseband demodulation and decoding processing on the frequency domain signal, recovering the data transmitted by the transmitting end, namely, encrypting the bit stream, and turning to step 6;
and 6, after the key is spliced, the encrypted bit stream is decrypted, the encryption data on the received overlay waveform is decrypted by using the key on the received underley waveform, and the original information data is recovered.
2. The security transmission method based on overlay and underlay cognitive radio signals according to claim 1, wherein in step 1, before transmission, encryption processing is performed on original information data to be transmitted by using a secret key to generate an encrypted bit stream; numbering and indexing the radio communication nodes of the transmitting end, splitting the secret key into M sections according to a protocol, wherein M is the number of the underley cognitive nodes; the cognitive node carries out spectrum access by using an overlay mode and an underley mode according to a spectrum sensing result, and specifically comprises the following steps of:
step 11, encrypting the original information data by using an Arnold scrambling algorithm; wherein the scrambling transformation is expressed asWherein x is n And y n Respectively and correspondingly representing the abscissa and the ordinate of the elements in the original information data matrix before scrambling; x is x n+1 And y n+1 Respectively and correspondingly representing the abscissa and the ordinate of the encrypted matrix elements after scramblingCoordinates; f (Key) is a function about the Key Key, mod (·) is a function of remainder, and N represents the number of columns of the original information data matrix;
step 12, splitting the Key Key based on the number of the underley nodes; key is jointly sent by M nodes, namely Key= [ Key 1 ,Key 2 ,…,Key M ]；
Step 13, the overlay performs access allocation on the subcarriers used by the encrypted bit stream according to the cognitive perception result, and the underlay performs access allocation on the subcarriers used by the secret key according to the cognitive perception result; the access allocation vectors of the overlay, underlay subcarriers are respectively and correspondingly denoted as a, a * I.e.Wherein a is i Is the allocation of the overlay ith subcarrier,/->Is the allocation situation of the ith subcarrier of the underlay, and the value of i is i epsilon {1,2, …, N F }；a i ∈{0,1},/>A value of 0 indicates that the subcarrier is not allocated to a node, and a value of 1 indicates that the subcarrier is allocated;
step 14, the overlay accesses the sub-carriers used by the encrypted bit stream according to the cognitive perception result, and the underlay accesses the sub-carriers used by the secret key according to the cognitive perception result; the usage-labeled variables for overlapping and underley sub-carriers are correspondingly denoted as u, u * I.e.Wherein the value range of the coverage ith subcarrier using the marking variable is u i E {0,1}, the index variable value range of the index for the ith subcarrier of underlay is +.>0 indicates that this subcarrier is not used by the node, and 1 indicates that this subcarrier is used by the node.
3. The security transmission method based on overlay and underlay cognitive radio signals according to claim 2, wherein in step 2, at the transmitting end, an overlay waveform is generated by using an SMSE model, specifically comprising the following steps:
step 21, modulating the encrypted bit stream, the modulated data being represented by d, i.e. from 1 to N F Modulated data of the sub-carriers of (a) are recorded asWherein N is F Is the number of sub-carriers, the range of the value of the data modulated by the ith sub-carrier is +.> Representing a complex field;
step 22, encoding the modulated data, the encoding being denoted by c, i.e. from 1 to N F The coding of the modulated data on the subcarriers of (a) is noted as
Step 23, shaping the spectrum of the waveform to be transmitted after encoding by changing the spectrum tap coefficient, and the windowing mode is expressed as
The time domain expression of the kth symbol transmitted on the mth subcarrier in the overlay waveform in step 24 isWherein N is F Representing the number of sub-carriers, j representing the imaginary partRe {.cndot. } represents the operation of taking the real part, a m ,u m ,c m ,d m.k ,w m Respectively representing the m-th subcarrier allocation, use, coding, modulation of the kth symbol and the windowed amplitude; f (f) m Representing carrier frequency, t n Representing symbol interval +.>Respectively representing the phases at the time of modulation, coding, windowing and orthogonal transformation.
4. The method for securely transmitting cognitive radio signals based on overlay and underlay according to claim 3, wherein in step 3, at the transmitting end, an underlay waveform is generated by using an SMSE model, specifically comprising the following steps:
step 31, modulating the key, d for data modulation * Representing, i.e. from 1 to N F Modulated data of the sub-carriers of (a) are recorded as
Step 32, coding the modulated key data; wherein, c is used for encoding * Representing, i.e. for a range from 1 to N F The coding of the modulated data on the subcarriers of (a) is noted as
Step 33, shaping the spectrum of the waveform to be transmitted after encoding by changing the tap coefficients of the spectrum, and the windowing mode is expressed as
Step 34, the time domain expression of the kth symbol transmitted on the mth subcarrier in the underley waveform is thatWherein N is F Representing subcarrier numberThe number j represents the imaginary part, re {. Cndot. } represents the real part taking operation, ++>Respectively representing the m-th subcarrier allocation, use, coding, modulation of the kth symbol and the windowed amplitude; />Indicating carrier frequency->Representing symbol interval +.>Respectively representing the phases at the time of modulation, coding, windowing and orthogonal transformation.
5. The method for securely transmitting cognitive radio signals based on overlay and underlay according to claim 4, wherein in step 4, in the transmitting end, the overlay waveform and the underlay waveform are added in frequency domain, and the IFFT operation is used to perform up-conversion to generate overlay and underlay time domain waveforms, specifically comprising the following steps:
step 41, overlapping the overlay waveform and the M underley waveforms to obtain a frequency domain aliasing waveform asWherein z represents an underley node variable, and the value of z is {1,2, …, M };
step 42, performing IFFT time domain transformation to obtain the time domain waveforms of overlay and underlay as
6. The method for safely transmitting cognitive radio signals based on overlay and underlay according to claim 5, wherein in step 5, the receiving end performs overlay and underlay full-band reception, changes a time domain signal into a frequency domain signal through down-conversion, serial-parallel conversion and FFT conversion, and then performs baseband demodulation and decoding processing on the frequency domain signal to recover data transmitted by the transmitting end, namely an encrypted bit stream, specifically comprising the following steps:
step 51, the receiving end performs overlapping and underley full-band receiving, and the expression of the received signal isWherein N is u Is the number of all cognitive nodes, < >>Representing a row convolution operation, H k [n]Representing the impulse response of the signal, gamma [ n ]]Is noise, H rf [n]Representing the receiver filter used;
step 52, recovering the data transmitted by the transmitting end through down-conversion, serial-to-parallel conversion, FFT conversion, baseband demodulation and decoding processingWherein f -1 (. Cndot.) represents operations such as baseband demodulation and decoding.
7. The security transmission method of cognitive radio signals based on overlay and underlay according to claim 6, wherein in step 6, the encrypted bit stream is decrypted after the key is spliced, the received encrypted data on the overlay waveform is decrypted by the key on the received underlay waveform, and the original information data is recovered, specifically comprising the following steps:
step 61, splicing the keys according to a key splicing mechanism, wherein the splicing expression is as followsWherein z is 1 ,z 2 ,…z M Representation matrix->Corresponding line number f of corresponding M underley nodes -1 (-) represents baseband demodulation and decoding operations;
step 62, usePerforming decryption processing; wherein x is n And y n Respectively and correspondingly representing the abscissa and the ordinate of matrix elements before scrambling; x is x n+1 And y n+1 Respectively and correspondingly representing the abscissa and the ordinate of the matrix elements after scrambling; f (Key) -1 Representing an inverse function to the Key operation, mod (·) is a function of the remainder, N representing the number of columns of the matrix before scrambling; and then decrypting and recovering the received encrypted bit stream by using the spliced Key Key to obtain the original information data.
CN202311682877.9A 2023-12-08 2023-12-08 Cognitive radio signal safe transmission method based on overlay and underly Pending CN117676561A (en)

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