Key encoding generation methods, devices and electronic equipment

Abstract

This application provides a key encoding generation method, apparatus, and electronic device, applied in the field of wireless communication technology. The method is applied to a transmitter in an OFDM-OAM communication system used in industrial equipment manufacturing, comprising: generating a first pilot signal based on a first transmission signal; transmitting the first pilot signal to a receiver, the first pilot signal being used by the receiver to determine a first mediation signal; estimating a first channel between the transmitter and receiver based on the first pilot signal and the first mediation signal; quantizing and encoding the first channel to generate a first encryption key for the transmitter during the communication phase; determining a second mediation signal based on a second pilot signal transmitted by the receiver, the second pilot signal being determined by the receiver based on the second transmission signal; and transmitting the second mediation signal to the receiver, the second mediation signal being used by the receiver to generate a second encryption key for the receiver during the communication phase. This improves the security of transmitted data and the communication system.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology in industrial equipment manufacturing, and in particular to a key encoding generation method, apparatus and electronic device. Background Technology

[0002] As global manufacturing competition enters a three-dimensional game of "technology-standards-rules," security challenges in the industrial equipment manufacturing sector (such as high-end equipment manufacturing) are exhibiting a systemic escalation. The deep integration of the Industrial Internet and artificial intelligence presents industrial equipment manufacturing with dual challenges of traditional and digital security. Currently, orbital angular momentum (OAM), as a novel physical dimension of electromagnetic waves, has attracted widespread attention in the field of wireless communication in recent years. Orthogonal Frequency Division Multiplexing (OFDM) technology, with its high spectral efficiency and resistance to multipath interference, has become a key technology in modern communication systems. Combining mature OFDM technology with OAM can construct an OFDM-OAM communication system, which can be applied to scenarios involved in industrial equipment manufacturing. This OFDM-OAM communication system, through the dual orthogonality of frequency domain subcarriers and OAM modes, enables wireless communication systems with stronger information carrying capacity and anti-interference capabilities than traditional communication systems.

[0003] Although OFDM-OAM communication systems offer extremely high data transmission rates, they still fall under the category of wireless communication. The broadcast nature of wireless communication means that all data transmitted through an OFDM-OAM system can be received by any receiver within the airspace where the system operates. This creates opportunities for both passive and active attacks from potential eavesdropping targets. In other words, the security of transmitted data is relatively low, leading to lower security for OFDM-OAM communication systems in industrial equipment manufacturing and making them vulnerable to attacks from potential eavesdropping targets.

[0004] Therefore, there is an urgent need for a key encoding generation method to encrypt transmitted data in order to improve the security of OFDM-OAM communication systems in industrial equipment manufacturing. Summary of the Invention

[0005] This application provides a key encoding generation method, apparatus, and electronic device to address the shortcomings of existing technologies where low data transmission security leads to low security in OFDM-OAM communication systems used in industrial equipment manufacturing, making them vulnerable to attacks from potential eavesdroppers. This method omits the key negotiation portion of traditional key encoding generation methods, providing a negotiation-free key encoding generation method. In other words, this method avoids key information leakage caused by information interaction during key negotiation in traditional methods by transferring key negotiation to subsequent communication transmission. It implicitly "negotiates" a more secure and difficult-to-crack encryption key through the interaction of pilot signals and modulation signals, improving the security of subsequent data transmission and thus enhancing the security of the OFDM-OAM communication system in industrial equipment manufacturing. This also makes the OFDM-OAM communication system less susceptible to attacks from potential eavesdroppers.

[0006] In a first aspect, embodiments of this application provide a key encoding generation method applied to a transmitter in an Orthogonal Frequency Division Multiplexing-Orbital Angular Momentum (OFDM-OAM) communication system used in industrial equipment manufacturing. The OFDM-OAM communication system further includes a receiver connected to the transmitter. The method includes:

[0007] A first pilot signal is generated based on the first transmitted signal; and the first pilot signal is sent to the receiving end, wherein the first pilot signal is used by the receiving end to determine the first modulation signal;

[0008] Based on the first pilot signal and the first mediation signal sent by the receiving end, the channel between the transmitting end and the receiving end is estimated to obtain the first channel;

[0009] The first channel is quantized and encoded to generate the first encryption key for the transmitting end during the communication phase;

[0010] Based on the second pilot signal sent by the receiving end, a second mediation signal is determined, the second pilot signal being determined by the receiving end based on the second transmission signal; and the second mediation signal is sent to the receiving end, the second mediation signal being used by the receiving end to generate a second encryption key for the receiving end during the communication phase.

[0011] Secondly, embodiments of this application provide a key encoding generation method applied to a receiver in an Orthogonal Frequency Division Multiplexing-Orbital Angular Momentum (OFDM-OAM) communication system used in industrial equipment manufacturing. The OFDM-OAM communication system further includes a transmitter connected to the receiver. The method includes:

[0012] Based on the first pilot signal sent by the transmitter, a first mediation signal is determined, wherein the first pilot signal is determined by the transmitter based on the first transmission signal; and the first mediation signal is sent to the transmitter, wherein the first mediation signal is used by the transmitter to generate a first encryption key for the transmitter during the communication phase;

[0013] A second pilot signal is generated based on the second transmission signal; and the second pilot signal is sent to the transmitting end, wherein the second pilot signal is used by the transmitting end to determine the second modulation signal;

[0014] Based on the second pilot signal and the second mediation signal sent by the transmitter, the channel between the receiver and the transmitter is estimated to obtain the second channel;

[0015] The second channel is quantized and encoded to generate a second encryption key for the receiving end during the communication phase.

[0016] Thirdly, embodiments of this application also provide a key encoding generation device, applied to a transmitter in an orthogonal frequency division multiplexing-orbit angular momentum (OFDM-OAM) communication system used in industrial equipment manufacturing. The OFDM-OAM communication system further includes a receiver connected to the transmitter. The device includes...

[0017] A first processing module is configured to generate a first pilot signal based on a first transmitted signal, wherein the first pilot signal is used by the receiving end to determine a first modulation signal;

[0018] The first transceiver module is used to send the first pilot signal to the receiving end;

[0019] The first processing module is further configured to estimate the channel between the transmitter and the receiver based on the first pilot signal and the first mediation signal sent by the receiver to obtain a first channel; quantize and encode the first channel to generate a first encryption key for the transmitter during the communication phase; and determine a second mediation signal based on the second pilot signal sent by the receiver, wherein the second pilot signal is determined by the receiver based on the second transmission signal.

[0020] The first transceiver module is further configured to send the second mediation signal to the receiving end, the second mediation signal being used by the receiving end to generate a second encryption key for the receiving end during the communication phase.

[0021] Fourthly, embodiments of this application also provide a key encoding generation device applied to a receiver in an orthogonal frequency division multiplexing-orbit angular momentum (OFDM-OAM) communication system used in industrial equipment manufacturing. The OFDM-OAM communication system further includes a transmitter connected to the receiver. The device includes:

[0022] The second processing module is used to determine a first modulation signal based on the first pilot signal sent by the transmitting end, wherein the first pilot signal is determined by the transmitting end based on the first transmission signal;

[0023] The second transceiver module is used to send the first mediation signal to the transmitter, and the first mediation signal is used by the transmitter to generate a first encryption key for the transmitter during the communication phase.

[0024] The second processing module is further configured to generate a second pilot signal based on the second transmitted signal;

[0025] The second transceiver module is further configured to send the second pilot signal to the transmitting end, wherein the second pilot signal is used by the transmitting end to determine the second modulation signal;

[0026] The second processing module is further configured to estimate the channel between the receiver and the transmitter based on the second pilot signal and the second mediation signal sent by the transmitter, to obtain a second channel; and to quantize and encode the second channel to generate a second encryption key for the receiver during the communication phase.

[0027] Fifthly, embodiments of this application also provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the key encoding generation method as described in either the first or second aspect above.

[0028] In a sixth aspect, embodiments of this application also provide a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the key encoding generation method as described in either the first or second aspect above.

[0029] In a seventh aspect, embodiments of this application also provide a computer program product, including a computer program that, when executed by a processor, implements the key encoding generation method as described in either the first or second aspect above.

[0030] The key encoding generation method, apparatus, and electronic device provided in this application embodiment involve a transmitting end generating a first pilot signal based on a first transmission signal and sending the first pilot signal to a receiving end. The first pilot signal is used by the receiving end to determine a first mediation signal. Based on the first pilot signal and the first mediation signal sent by the receiving end, the channel between the transmitting end and the receiving end is estimated to obtain a first channel. The first channel is quantized and encoded to generate a first encryption key for the transmitting end during the communication phase. Based on a second pilot signal sent by the receiving end, a second mediation signal is determined by the receiving end based on the second transmission signal. The second mediation signal is then sent to the receiving end, and the second mediation signal is used by the receiving end to generate a second encryption key for the receiving end during the communication phase. This method omits the key negotiation part of traditional key encoding generation methods, making it a negotiation-free key encoding generation method. In other words, by transferring key negotiation to subsequent communication transmission, this method avoids the key information leakage caused by information exchange during key negotiation in traditional key encoding generation methods. It implicitly "negotiates" a more secure and difficult-to-crack encryption key through the interaction of pilot signals and modulation signals, thereby improving the security of subsequent data transmission and enhancing the security of the OFDM-OAM communication system in industrial equipment manufacturing. This also makes the OFDM-OAM communication system less susceptible to attacks from potential eavesdropping devices. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is one of the flowcharts illustrating the key encoding generation method provided in the embodiments of this application;

[0033] Figure 2 This is a schematic diagram of the UCA antenna at the transmitting end and the UCA antenna at the receiving end provided in the embodiments of this application;

[0034] Figure 3 This is a schematic diagram illustrating the encryption key generation stage and the encryption communication stage provided in the embodiments of this application;

[0035] Figure 4 This is a second schematic flowchart of the key encoding generation method provided in the embodiments of this application;

[0036] Figure 5 This is a schematic diagram of the UCA antenna of the eavesdropping terminal provided in an embodiment of this application;

[0037] Figure 6 This is a schematic diagram illustrating the relationship between confidentiality capacity and signal-to-noise ratio (SNR) provided in an embodiment of this application.

[0038] Figure 7 The bit error rate (BER) and offset angle provided in the embodiments of this application are... Relationship diagram;

[0039] Figure 8 This is one of the structural schematic diagrams of the key encoding generation device provided in the embodiments of this application;

[0040] Figure 9 This is a second schematic diagram of the key encoding generation device provided in the embodiments of this application;

[0041] Figure 10 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] To better understand the embodiments of this application, the Orthogonal Frequency Division Multiplexing - Orbital Angular Momentum (OFDM-OAM) communication system involved in the embodiments of this application will first be described in detail:

[0044] The aforementioned OFDM-OAM communication system is a communication system based on two-dimensional inverse fast fourier transform (2-D IFFT) operations / two-dimensional fast fourier transform (2-D FFT) operations. The number of modulation points in the 2-D IFFT / 2-D FFT operations can be... express, It is an integer greater than 1.

[0045] The OFDM-OAM communication system mentioned above uses Time Division Duplex (TDD) mode.

[0046] Optionally, the OFDM-OAM communication system described above may include a transmitter and a receiver. Both the transmitter and the receiver are electronic devices.

[0047] Specifically, both the transmitter and receiver include a Uniform Circular Array (UCA) antenna, and the number of antennas in each UCA antenna is available. express, It is an integer greater than 1.

[0048] It should be noted that each UCA antenna is a type of UCA antenna element, also known as... Each of the array elements' UCA antennas The UCA antenna of the array element generates a maximum of Vortex waves of various modes, the number of OAM modes for each mode of vortex wave is available. It means that, among them, In addition, the total number of OAM modes, i.e., the total number of modes, is available. express, It is an integer greater than 1.

[0049] Optionally, the aforementioned transmitting end may include: a computer, a mobile terminal, a wearable device, and mechanical equipment, etc.

[0050] Optionally, the receiving end may include: a computer, a mobile terminal, a wearable device, and mechanical equipment, etc.

[0051] It should be noted that the Physical Layer Key Generation (PKG) method, as a supplementary method to classical cryptography, has the advantages of being lightweight, resistant to quantum attacks, and having strong key dynamics compared to traditional cryptography. The PKG method directly utilizes the physical characteristics of the wireless channel to generate encryption keys without the need for pre-distribution of key materials, and can be used in the key encoding generation method provided in the embodiments of this application.

[0052] Optionally, the aforementioned OFDM-OAM communication system is a communication system used in the manufacturing of high-end equipment.

[0053] Optionally, the aforementioned high-end equipment may include: aerospace equipment, rail transit equipment, marine engineering equipment, and intelligent manufacturing equipment, etc.

[0054] Optionally, the high-end equipment manufacturing field may include the following application scenarios: 1. Full life cycle management of aerospace equipment (such as satellite on-orbit operation and maintenance and safety protection, aero-engine health management, etc.); 2. Intelligent operation and maintenance of rail transit equipment (such as prediction of the remaining life of high-speed rail bearings, intelligent train network control system); 3. Extreme environment operation of marine engineering equipment (such as dynamic positioning of deep-sea drilling platforms, submarine pipeline inspection robots, etc.); 4. Extreme condition support for emergency equipment (such as swarm operation of fire-fighting robots in high-rise buildings).

[0055] For example, in the application scenario of satellite on-orbit operation and maintenance and security protection: the transmitting end is ground control equipment, and the receiving end is the satellite. When the ground control equipment performs on-orbit operation and maintenance and security protection for the satellite, the ground control equipment can encrypt the transmitted plaintext data (such as operation and maintenance and protection instructions) to obtain the first ciphertext; the satellite then decrypts the first ciphertext to obtain the target plaintext, and executes the operation corresponding to the operation and maintenance and protection instructions based on the target plaintext.

[0056] It should be noted that other application scenarios in the field of high-end equipment manufacturing, such as industrial robot control scenarios (e.g., control applications of industrial robotic arms), CNC system safety certification scenarios (e.g., certification of CNC machine tools), and smart factory equipment collaboration scenarios (e.g., data transmission of smart factory production line equipment clusters), are all within the scope of protection of this application, and will not be elaborated here.

[0057] The key encoding generation method provided in this application embodiment will be described in detail below, taking the transmitter and receiver of an OFDM-OAM communication system in high-end equipment manufacturing as the main execution entities:

[0058] Figure 1 This is a flowchart illustrating the key encoding generation method provided in an embodiment of this application. For example... Figure 1 As shown, the method includes the following steps 101-112.

[0059] Step 101: The transmitting end generates a first pilot signal based on the first transmission signal.

[0060] In some embodiments, the first transmitted signal is × dimensional data blocks, and All are integers greater than 1.

[0061] It should be noted that the aforementioned first transmitted signal can be used express, express In the OAM mode, the first Data in OAM mode. The first transmitted signal. Depend on The data composition of each OAM pattern Represents the number of OFDM subcarriers, where, .

[0062] Thus, the transmitting end generates a first pilot signal based on the first transmitted signal, which may include: the transmitting end performing frequency domain analysis on the first transmitted signal. The OFDM signal is obtained by performing a 2D inverse fast Fourier transform (2-D IFFT) on the points with respect to the rows. This represents the number of modulation points in a 2-D IFFT operation. It is an integer greater than 1; the transmitter performs OFDM signal in the spatial domain. A 2-D IFFT operation on the points about the columns yields the OFDM-OAM signal. This indicates the number of antennas in a uniform circular array UCA antenna at the transmitting end. A UCA antenna is a type of UCA antenna array element. It is an integer greater than 1; the transmitter inserts a cyclic prefix into the OFDM-OAM signal, and then performs up-conversion processing on the radio frequency end to obtain the first pilot signal.

[0063] In this embodiment of the application, during the process of determining the first pilot signal, the transmitting end can first perform frequency domain analysis on the first transmitted signal. A point-to-row 2D IFFT operation is performed to modulate the first transmitted signal into an OFDM signal. Then, the transmitter performs spatial operations on the OFDM signal. A 2-D IFFT operation is performed on the column, at which point the OFDM signal can be modulated into an OFDM-OAM signal. Then, to combat multipath effects and inter-symbol interference and improve signal robustness, the transmitter inserts a cyclic prefix (cp) into the OFDM-OAM signal. Finally, it undergoes up-conversion processing at the RF end to obtain the first pilot signal, ready for subsequent transmission to the receiver.

[0064] In some embodiments, the expression for the OFDM-OAM signal is:

[0065] .

[0066] in, Indicates OFDM-OAM signal; Represents the antenna power allocation matrix. This indicates the UCA antenna at the transmitting end. The power of each antenna; express The Discrete Fourier Transform (DFT) matrix of a point; express The inverse discrete Fourier transform (IDFT) matrix of a point; Indicates the first transmitted signal. express In the OAM mode, the first Data for each OAM pattern; Represents the OFDM modulation matrix; Represents the OFDM modulation matrix The inverse matrix; Represents the discrete Fourier transform matrix The conjugate transpose of is a type of OAM modulation matrix; Represents the OFDM modulation matrix The conjugate transpose of .

[0067] In some embodiments, the OAM modulation matrix The expression is:

[0068] .

[0069] in, , represents the complex exponent term; Indicates by The azimuth angle of the UCA antenna array element composed of 10 antennas ; Indicates the first Number of OAM modes.

[0070] It should be noted that the transmitting end can use an IDFT matrix instead of an OAM modulation matrix, when the number of OAM modes... At that time, the number of activated modes is .

[0071] Step 102: The transmitter sends the first pilot signal to the receiver.

[0072] The receiver receives the first pilot signal sent by the transmitter.

[0073] In some embodiments, the transmitting end sending a first pilot signal to the receiving end may include: the transmitting end sending the first pilot signal to the receiving end through a wireless channel.

[0074] In this embodiment of the application, during the process of the transmitter sending the first pilot signal to the receiver, the transmitter can send the first pilot signal to the wireless channel through the UCA antenna of the transmitter, and then send the first pilot signal to the receiver through the wireless channel. This can effectively ensure the transmission quality of the first pilot signal in complex environments.

[0075] It should be noted that the channel model described above is a wireless channel model based on a UCA (Multiple-Input Multiple-Output) (MIMO) system. The channel matrix of this wireless channel model can be obtained from... express.

[0076] In some embodiments, the expression for the first pilot signal transmitted via the wireless channel is:

[0077] .

[0078] Indicates the first pilot signal; It can represent the number of UCA antennas at the transmitting end, or the number of array elements of the UCA antenna at the transmitting end; This represents the number of modulation points in a 2-D IFFT operation; The channel matrix represents the wireless channel; Represents the antenna power allocation matrix. This indicates the UCA antenna at the transmitting end. The power of each antenna; express The discrete Fourier transform matrix of a point; Represents the discrete Fourier transform matrix The conjugate transpose of is a type of OAM modulation matrix; Indicates the first transmitted signal. express In the OAM mode, the first Data for each OAM pattern; Represents the OFDM modulation matrix; Represents the OFDM modulation matrix The conjugate transpose of ; This indicates that the mean is zero and the variance is... The complex Gaussian white noise matrix satisfies , express An identity matrix of order 1.

[0079] Step 103: The receiving end determines the first modulation signal based on the first pilot signal sent by the transmitting end.

[0080] In some embodiments, the receiving end determines the first mediation signal based on the first pilot signal sent by the transmitting end, which may include: the receiving end receiving the first pilot signal sent by the transmitting end through a wireless channel, the first pilot signal being obtained by the transmitting end performing a two-dimensional inverse fast Fourier transform (2-D IFFT) operation on the first transmitted signal; the receiving end first performing down-conversion processing on the first pilot signal at the radio frequency end, and then removing the cyclic prefix at the baseband end to obtain the processed first pilot signal; the receiving end performing a two-dimensional fast Fourier transform (2-D FFT) operation on the processed first pilot signal to obtain the first mediation signal.

[0081] In this embodiment of the application, during the process of determining the first modulation signal, the receiving end can first perform down-conversion processing on the first pilot signal sent by the transmitting end at the radio frequency end, and then remove the cyclic prefix (cp) at the baseband end to obtain the processed first pilot signal. Then, the processed first pilot signal is subjected to a two-dimensional fast Fourier transform (2-DFFT) operation to obtain the first modulation signal, which is ready to be sent to the transmitting end later.

[0082] In some embodiments, the expression for the first modulation signal, determined based on the first pilot signal received via a wireless channel, is as follows:

[0083] .

[0084] in, This indicates the first mediation signal; express The first of the sub-modulation signals Each sub-modulation signal corresponds to a different OAM mode.

[0085] It should be noted that the above OFDM-OAM signal And the aforementioned first mediation signal All of these are signal models of the aforementioned OFDM-OAM communication system.

[0086] The channel matrix of the above wireless channels is described below. The construction of [the system] will be explained in detail:

[0087] In a line-of-sight channel, a pair of transmitting antennas (i.e., the first...) The transmitting element and the receiving antenna (i.e., the first transmitting element) and the receiving antenna The modeling expression for the transfer function of the receiving array elements in free space is: .

[0088] Among them, the The transmitting element is an element in the UCA antenna at the transmitting end, the th Each receiving element is an element in the UCA antenna at the receiving end; Indicates the first The number of launch elements to the first Channel gain between receiver array elements; This represents a constant related to signal attenuation; Indicates the wavelength of the OAM signal; Indicates the first The number of launch elements to the first The transmission distance between each receiving array element.

[0089] The transfer function can be seen from the above modeling expression. Mainly about wavelength and transmission distance A function of wavelength. The distance between the transmitting and receiving antennas in a UCA-MIMO system is generally fixed, therefore, calculating the distance between the transmitting and receiving antennas is particularly important.

[0090] Considering that it is difficult to achieve strict alignment between the UCA antennas at the transmitting and receiving ends in a practical OFDM-OAM communication system, for generalization, a channel matrix can be constructed for the wireless channel under the condition of misalignment between the transmitting and receiving ends. .

[0091] Specifically, such as Figure 2 The diagram shown is a schematic representation of the UCA antenna at the transmitting end and the UCA antenna at the receiving end provided in an embodiment of this application. (In conjunction with...) Figure 2 The radius of both the transmitting end's UCA antenna and the receiving end's UCA antenna can be used. Indicated. The center of the UCA antenna at the transmitting end can be used. Indicates that the center of the UCA antenna at the receiving end is available. Indicates. Center With the center The distance between them is available express.

[0092] Based on this, for the UCA antenna at the transmitting end, with the center... Let O be the origin of the coordinate system and the UCA plane be... The surface is used to construct a three-dimensional coordinate system for the transmitter, which can be used... express.

[0093] For the UCA antenna at the receiving end, with the center Construct a coordinate system parallel to the three-dimensional coordinate system with the origin as the coordinate origin. Three-dimensional coordinate system Then the three-dimensional coordinate system Around The axis according to the rotation angle After rotation, a three-dimensional coordinate system is obtained. .

[0094] At this time, the above three-dimensional coordinate system and the above three-dimensional coordinate system It can simulate the situation where the UCA antennas of the transmitter and receiver are misaligned in an OFDM-OAM communication system under actual conditions.

[0095] Assume the first Each transmitting element is in the above three-dimensional coordinate system The coordinates below are , Indicates the first The azimuth angle of the transmitting element in the UCA antenna at the transmitting end. Then, according to the first coordinate transformation formula, the azimuth of the first element is determined. Each receiving element in the above three-dimensional coordinate system The coordinates below.

[0096] Among them, the The first transmitting element can be represented by A; the second... Each receiver array element can be represented by B.

[0097] The first coordinate transformation formula mentioned above is:

[0098] .

[0099] Indicates the first Each receiving element in the above three-dimensional coordinate system The coordinates below; Indicates the first The azimuth angle of each receiving element in the UCA antenna at the receiving end.

[0100] At this time, the The number of launch elements to the first Transmission distance between each receiving array element The expression is:

[0101] .

[0102] Based on this, after determining the channel gain between each pair of transmit and receive antennas, the receiver can obtain the channel matrix of the aforementioned wireless channel. The expression is: = .

[0103] It should be noted that, in terms of rotation angle Under these conditions, the UCA antenna at the transmitting end and the UCA antenna at the receiving end are in ideal alignment. At this time, the first... Each receiving element in the above three-dimensional coordinate system The coordinates below are , No. The number of launch elements to the first Transmission distance between each receiving array element The expression can be simplified to: .

[0104] Meanwhile, the aforementioned channel matrix It is a cyclic symmetric matrix, which can be decomposed into:

[0105] .

[0106] in, This represents a diagonal matrix, where the diagonal elements are the channel matrix. In Each feature value.

[0107] Based on this, the aforementioned first mediation signal The expression can be simplified to:

[0108] .

[0109] It should be noted that the aforementioned first mediation signal The simplified expression shows that, assuming the UCA antennas at the transmitting and receiving ends are perfectly aligned, the entire channel matrix is ​​equivalent to... The channel matrix is ​​a diagonal matrix, indicating that when the UCA antennas at the transmitting and receiving ends are aligned, the transmission of each OMA mode will not interfere with each other. The channels corresponding to each OMA mode can be regarded as independent sub-channels. This also explains why OAM modes are orthogonal to each other during transmission as data transmission channels. This diagonal channel matrix allows the complex equalization operation to be omitted at the receiving end to compensate for the channel matrix. The impact on the first pilot signal. However, as long as the UCA antennas at the transmitting end and the receiving end are not aligned, even a small offset angle or displacement will affect the channel matrix. Since they are no longer cyclic symmetric matrices, they cannot be simplified as shown in the above formula. As a result, intermodal crosstalk (OAM) will occur at the receiving end, making it impossible to recover the original data, i.e., the first mediated signal cannot be obtained.

[0110] Step 104: The receiver sends the first mediation signal to the transmitter.

[0111] The transmitter receives the first mediation signal sent by the receiver.

[0112] Optionally, the receiving end sending the first mediation signal to the transmitting end may include: the receiving end sending the first mediation signal to the transmitting end via a wireless channel.

[0113] Optionally, the transmitting end receiving the first mediation signal sent by the receiving end may include: the transmitting end receiving the first mediation signal sent by the receiving end through a wireless channel.

[0114] Step 105: The transmitter estimates the channel between the transmitter and the receiver based on the first pilot signal and the first mediation signal sent by the receiver, and obtains the first channel.

[0115] Optionally, the transmitting end estimates the channel between the transmitting end and the receiving end based on the first pilot signal and the first mediation signal sent by the receiving end to obtain the first channel. This may include: the transmitting end estimating the channel between the transmitting end and the receiving end using the least squares (LS) method based on the first pilot signal and the first mediation signal sent by the receiving end to obtain the first channel.

[0116] The least squares method refers to solving a system of linear equations based on the known transmitted signal (i.e., the first pilot signal) and the received signal (i.e., the first modulation signal) to find the channel parameters that minimize the sum of squared errors between the received signal and the transmitted signal transmitted through the wireless channel.

[0117] In other words, the first channel mentioned above is a channel parameter.

[0118] Step 106: The transmitter performs quantization encoding on the first channel to generate the first encryption key for the transmitter during the communication phase.

[0119] Optionally, the transmitting end performs quantization encoding on the first channel to generate the first encryption key for the transmitting end during the communication phase, which may include one of the following implementation methods:

[0120] Implementation Method 1: The transmitter rounds the first channel and encodes the rounded first channel into binary to generate the first encryption key for the transmitter during the communication phase.

[0121] Optionally, the rounding operation can be rounding up, rounding down, or rounding to the nearest integer, depending on the implementation requirements and channel characteristics.

[0122] The above implementation method 1 has the advantages of being simple to implement, having low computational complexity, and being suitable for scenarios with high requirements for key generation speed or limited computing resources.

[0123] Implementation Method 2: The transmitter determines the channel characteristics of the first channel and quantizes and encodes the channel characteristics to generate the first encryption key for the transmitter during the communication phase.

[0124] Optionally, channel characteristics may include: statistical properties of channel gain (such as mean and variance), phase distribution, and multipath delay.

[0125] Optionally, the quantization method for quantizing channel features may include uniform quantization, non-uniform quantization, or cluster-based quantization, depending on the distribution characteristics of the channel features and the key generation requirements.

[0126] Implementation method 2 described above can fully utilize the unique characteristics of the channel to improve the uniqueness and security of the first encryption key. The quantization operation can be optimized based on the distribution characteristics of the channel features, further improving the key generation efficiency.

[0127] It should be noted that during the encryption key generation stage, while the transmitting end generates the first encryption key for the transmitting end in the communication stage, the receiving end can also generate the second encryption key for the receiving end in the communication stage. The process of the receiving end generating the second encryption key is as follows: steps 107-112.

[0128] Since the process of generating the first encryption key at the transmitting end is similar to the process of generating the second encryption key at the receiving end, steps 107-112 will not be described in detail below.

[0129] Step 107: The receiving end generates a second pilot signal based on the second transmitted signal.

[0130] Step 108: The receiver sends a second pilot signal to the transmitter.

[0131] The transmitting end receives the second pilot signal sent by the receiving end.

[0132] Step 109: The transmitting end determines the second modulation signal based on the second pilot signal sent by the receiving end.

[0133] Step 110: The transmitter sends a second mediation signal to the receiver.

[0134] The receiver receives the second mediation signal sent by the transmitter.

[0135] Step 111: The receiver estimates the channel between the receiver and the transmitter based on the second pilot signal and the second mediation signal sent by the transmitter, and obtains the second channel.

[0136] Step 112: The receiving end performs quantization encoding on the second channel to generate the second encryption key for the receiving end during the communication phase.

[0137] It should be noted that during the encryption key generation stage, both the transmitting end and the receiving end can generate corresponding encryption keys, and the timing of the transmitting end generating the first encryption key and the timing of the receiving end generating the second encryption key are not limited.

[0138] In this embodiment, the key encoding generation method implemented in steps 101-112 omits the key negotiation part of the traditional key encoding generation method. It is a negotiation-free key encoding generation method. In other words, this method avoids the key information leakage caused by information interaction during key negotiation in the traditional key encoding generation method by transferring key negotiation to subsequent communication transmission. It implicitly "negotiates" a more secure and difficult-to-crack encryption key through the interaction of pilot signals and modulation signals, thereby improving the security of subsequent data transmission and enhancing the security of the OFDM-OAM communication system in industrial equipment manufacturing. This also makes the OFDM-OAM communication system less susceptible to attacks from potential eavesdropping terminals.

[0139] It should be noted that, in addition to the aforementioned encryption key generation stage (steps 101-112), this application embodiment also involves an encrypted communication stage (steps 113-118). The wireless channels used in these two stages are different. Specifically, the wireless channel used in the encryption key generation stage can be... This indicates that the wireless channel used during the encrypted communication phase is available. This indicates that the aforementioned OFDM-OAM communication system is in... Encryption key generation is implemented at all times. Encryption of communication with encryption keys is achieved at all times, among which, , Indicates coherence time. This represents the Doppler frequency shift. Based on the short-time reciprocity of the wireless channel, during the coherence time... It can be assumed that the channels experience the same channel fading, and vice versa.

[0140] For example, such as Figure 3 The diagram shown is a schematic representation of a scenario involving the encryption key generation stage and the encrypted communication stage provided in an embodiment of this application. Combined with... Figure 3 Regarding the encryption key generation phase, assume the transmitter is the first legitimate communication user, i.e., Alice; and the receiver is the second legitimate communication user, i.e., Bob. Alice and Bob communicate via a line-of-sight (LoS) channel. During the encryption key generation phase... At a set time, Alice and Bob will both be on the same side. Internal pilot signals are transmitted to probe the channel, with a preset time. Less than coherence time The entire encryption key generation phase employs channel estimation based on training symbols, meaning both the sender and receiver know the pilot signals. It is assumed that Alice's end knows the first pilot signal is available. This indicates that at this time, the first mediation signal is... , Indicates the first pilot signal The total channel traversed by demodulation from Alice's end to Bob's end; assuming Bob's end knows the second pilot signal is available. This indicates that at this time, the second mediation signal is... , Indicates the second pilot signal The total channel traversed by demodulation from Bob's end to Alice's end.

[0141] Alice's end is based on the first pilot signal and the first mediation signal The least squares method is used to analyze the channel. Estimation is performed to obtain the first channel. Bob's end is based on the second pilot signal. Second mediation signal The least squares method is used to analyze the channel. Estimation is performed to obtain the second channel. .

[0142] Due to the short-term reciprocity of wireless channels, it can be considered that... At this time, it can be As the key source for Alice, and will This serves as the key source for Bob's end. Based on this, Alice's end can control the first channel. Quantization encoding is performed to generate the first encryption key for Alice during the communication phase. Bob's end to the second channel Quantization encoding is performed to generate a second encryption key for Bob's end during the communication phase. .

[0143] It should be noted that, due to the first mediation signal Second mediation signal Noise exists in both, therefore, the first encryption key Second encryption key There will be different bits.

[0144] The encrypted communication phase is described in detail below:

[0145] Figure 4 This is a flowchart illustrating the key encoding generation method provided in an embodiment of this application. For example... Figure 4 As shown, after step 112, the method further includes steps 113 and 118.

[0146] Step 113: The transmitting end performs error correction encoding on the transmitted plaintext data to obtain the first plaintext.

[0147] In this context, plaintext transmission data refers to raw data to be sent, without any encryption or encoding, typically existing as a binary bitstream. In OFDM-OAM communication systems, the plaintext transmission data may optionally include various types of information such as text, images, and audio. This plaintext transmission data can be used... express.

[0148] Error correction coding (ECC) refers to adding redundant information to the original data so that the receiving end can detect and correct errors caused by noise or interference during transmission. The core objective of error correction coding is to improve the reliability of data transmission.

[0149] The first plaintext is the transmitted data plaintext after error correction coding, which can be used... express.

[0150] Step 114: The transmitting end determines the first ciphertext based on the first encryption key and the first plaintext.

[0151] In some embodiments, the transmitter determines the first ciphertext based on the first encryption key and the first plaintext, which may include: the transmitter obtaining the first ciphertext according to an encryption formula.

[0152] The encryption formula is as follows: ;

[0153] This indicates the first ciphertext; Indicates the first plaintext; Indicates the first encryption key; This indicates the XOR operation.

[0154] In this embodiment of the application, the transmitting end may use a first encryption key. Regarding the first plaintext mentioned above Encryption is performed; specifically, using an encryption formula, the first ciphertext can be obtained. .

[0155] Step 115: The transmitter sends the first ciphertext to the receiver.

[0156] The receiving end receives the first ciphertext sent by the transmitting end.

[0157] Optionally, the transmitting end sending the first ciphertext to the receiving end may include: the transmitting end transmitting through a channel in the OFDM-OAM communication system. Send the first ciphertext to the receiving end.

[0158] Optionally, the receiving end receiving the first ciphertext sent by the transmitting end may include: the receiving end receiving the first ciphertext through a channel in the OFDM-OAM communication system. Receive the first ciphertext sent by the transmitter.

[0159] Step 116: The receiver performs OFDM-OAM demodulation on the first ciphertext sent by the transmitter to obtain the second ciphertext.

[0160] Step 117: The receiving end decrypts the second ciphertext using the second encryption key to obtain the second plaintext.

[0161] In some embodiments, the receiving end decrypts the second ciphertext according to the second encryption key to obtain the second plaintext, which may include: the receiving end obtaining the second plaintext according to the decryption formula.

[0162] The decryption formula is as follows: ;

[0163] Indicates the second plaintext; This indicates the second ciphertext; This represents the second encryption key; This indicates the XOR operation.

[0164] In this embodiment of the application, the receiving end may use a second encryption key. Regarding the aforementioned second ciphertext Encryption is performed; specifically, a decryption formula is used to obtain the second plaintext. .

[0165] Step 118: The receiving end decodes and corrects the second plaintext to obtain the third plaintext.

[0166] The third plaintext is available. express.

[0167] In this embodiment of the application, due to the influence of channel equalization and noise during communication transmission, the second ciphertext With the first ciphertext There will be some differences; therefore, by using the above decryption formula, the second plaintext is obtained. Then, the second plaintext can be... Decode and correct errors to recover the third plaintext This non-negotiation key encoding generation method uses a second encryption key. Second ciphertext Error correction is concentrated in the encryption communication stage of the codec encoding and decoding process.

[0168] For example, combined Figure 3 Regarding the encrypted communication phase, in At that moment, Alice and Bob both used the first encryption key obtained during the encryption key generation phase. Second encryption key This is used for encrypted communication. First, similar to the encryption key generation phase, Alice and Bob each probe and estimate the channel for subsequent channel equalization. Then, Alice transmits plaintext data... Error correction encoding is performed to obtain the first plaintext. Then use the first encryption key Regarding the first plaintext Encryption is performed to obtain the first ciphertext. Alice communicates via the OFDM-OAM communication system. The first ciphertext Send to Bob's end; Bob's end sends the first ciphertext to the transmitter. OFDM-OAM demodulation was performed to obtain the second ciphertext. Then use the second encryption key For the second ciphertext Decryption yields the second plaintext. And then regarding the second plaintext Decode and correct errors to obtain the third plaintext. The entire process couples the encryption key generation phase with the encryption communication phase, saving the communication resources required for key information negotiation.

[0169] Optionally, the aforementioned OFDM-OAM communication system may also include an eavesdropping terminal, also known as an eavesdropper. This eavesdropping terminal includes a UCA antenna, the number of which can be configured to... express.

[0170] For example, combined Figure 3 ,like Figure 5 The diagram shown is a schematic of the UCA antenna of the eavesdropping terminal provided in an embodiment of this application. Assuming the eavesdropping terminal is the Eve terminal, in... Figure 5 middle, Indicates the center of the UCA antenna at the Alice end. Center of the UCA antenna at the Bob end The distance between them; Indicates the center The center of the UCA antenna at Eve end The distance between them; Indicates the center With the center The distance between them. The angle by which the UCA plane at the Bob end deviates from the vertical direction, which is the aforementioned rotation angle; express The angle between the UCA plane at Eve's end; Eve represents the angle of deviation from the horizontal direction. This refers to the channel between Alice's end and Bob's end, i.e., the first channel mentioned above; This refers to the channel between Bob's end and Alice's end, i.e., the second channel mentioned above; This represents the channel between Alice and Eve. This represents the channel between Bob and Eve.

[0171] The first UCA antenna at Alice's end The first transmitting element and the first UCA antenna at Bob's end Transmission distance between each receiving array element Transmission distance can be used The expression is calculated. Considering the symmetry of the UCA antenna, in this embodiment, the Eve end is placed near the Bob end. To facilitate the analysis of the Bob end's coordinates, it can be set... That is, the Eve end always faces the Alice end. In this case, the second coordinate transformation formula can be used to determine the first position of the UCA antenna at the Eve end. Each element in the three-dimensional coordinate system The coordinates below.

[0172] The second coordinate transformation formula mentioned above is:

[0173] .

[0174] Indicates the first Each element in the above three-dimensional coordinate system The coordinates below.

[0175] At this time, the The number of launch elements to the first Transmission distance between individual elements The expression is:

[0176]

[0177] .

[0178] It should be noted that the first The receiving array element to the first Transmission distance between individual elements The calculation process is the same as the above transmission distance. The calculation process is similar and will not be elaborated here.

[0179] Based on this, the channel matrix of the UCA-MIMO system between Alice and Eve can be determined. The expression is: = The channel matrix of the UCA-MIMO system between Bob and Eve can be determined. The expression is: = .

[0180] It should be noted that the wireless channel used during the encryption key generation phase is available. This indicates that the wireless channel used during the encrypted communication phase is available. This means that it is difficult for the eavesdropping end to estimate the channel fading in the encryption key generation stage based on the channel fading in the encryption communication stage, thereby obtaining the encryption key. This can effectively enhance the confidentiality of the aforementioned OFDM-OAM communication system.

[0181] Optionally, to analyze the confidentiality of the key encoding generation method, it is assumed that the eavesdropping capability of the Eve end is greater than a preset eavesdropping capability threshold, that is, the Eve end has a strong eavesdropping capability. At any given moment, Eve eavesdrops on the first pilot signal sent by Alice and the second pilot signal sent by Bob; then, she determines the first distance between Eve and Alice, and the second distance between Eve and Bob; next, based on the first and second distances, she determines the channel distance from Alice to Eve. The channel between Bob's end and Eve's end Choose one channel as the key source for Eve, and quantize the key source to obtain Eve's third encryption key during the communication phase. Therefore, the third encryption key is used. Regarding the aforementioned first ciphertext To decipher.

[0182] Wherein, the first distance is the aforementioned distance. The second distance is the distance mentioned above. .

[0183] Optionally, the channel corresponding to the larger of the first and second distances is the key source for Eve.

[0184] It should be noted that the channel corresponding to a larger distance has richer channel information. Furthermore, the timing of Eve's determination of the first and second distances is not limited.

[0185] To more intuitively demonstrate the security capabilities of an OFDM-OAM communication system, other devices can use metrics such as Key Disagreement Rate (KDR), Bit Error Rate (BER), and security capacity. This will help to better analyze the aforementioned confidentiality capabilities.

[0186] Optionally, other devices may be electronic devices independent of the OFDM-OAM communication system, or electronic devices other than the transmitter, receiver and eavesdropping device included in the OFDM-OAM communication system, without specific limitations here.

[0187] Here, KDR refers to the difference between the initial key sequences obtained by the transmitter and receiver, which is the ratio of the number of mismatched bits to the total number of bits in the quantized output. Specifically, it refers to the first encryption key. Second encryption key Bit inconsistency rate between them.

[0188] BER is one of the important indicators for measuring the transmission quality of digital communication systems (i.e., OFDM-OAM communication systems). It refers to the probability that binary symbols are transmitted incorrectly in a digital communication system. It is approximately equal to the ratio of the number of binary symbols transmitted incorrectly to the total number of transmitted symbols. It can reflect the reliability of OFDM-OAM communication systems in the encrypted communication stage.

[0189] Security Capacity This refers to Alice and Bob probing the channel from the first channel. Second Channel The maximum number of key bits that can be extracted.

[0190] The following section uses other devices as the execution subject to discuss the confidentiality capacity. The process of determining [the value] will be explained in detail:

[0191] Optionally, Alice sends the first ciphertext to Bob. During the process involving Eve, other devices determine a first distance between Eve and Alice, and a second distance between Eve and Bob. These other devices determine the first distance between Eve and Alice, and the second distance between Eve and Bob. Based on the first and second distances, these other devices determine the channel distance from Alice to Eve. The channel between Bob's end and Eve's end The other device selects a channel between Alice and Bob as the key source; the other device then uses the key source and the first channel between Alice and Bob. and the second channel between Bob's end and Alice's end. Determine the confidentiality capacity Among them, confidentiality capacity Less than the preset security capacity Preset confidentiality capacity It is based on the first channel Second Channel It's confirmed.

[0192] It should be noted that the timing of other devices determining the first and second distances is not limited.

[0193] It should be noted that, in the absence of eavesdropping devices, the preset security capacity is... This represents the theoretical maximum security capacity in an OFDM-OAM communication system.

[0194] Optionally, preset security capacity It is based on the first channel The autocovariance matrix, the second channel The autocovariance matrix and the first channel Second Channel The covariance matrix is ​​determined by it.

[0195] Optionally, other devices determine the channel between Alice and Eve based on a first distance and a second distance. The channel between Bob's end and Eve's end Selecting a channel between the two distances as the key source for Eve can include: if the first distance is greater than the second distance, then the first channel is used as the key source; if the first distance is less than the second distance, then the second channel is used as the key source; if the first distance is equal to the second distance, then either the first channel or the second channel is used as the key source.

[0196] In this embodiment, after determining the first distance and the second distance, other devices can compare the first distance and the second distance, and use the channel corresponding to the larger of the two distances as the key source. Specifically, if the first distance is greater than the second distance, it indicates that the first distance is larger, and in this case, the first channel corresponding to the first distance is used as the key source; if the first distance is less than the second distance, it indicates that the second distance is larger, and in this case, the second channel corresponding to the second distance is used as the key source. Of course, there may be cases where the first distance and the second distance are the same. In this case, any channel corresponding to either distance can be selected as the key source to ensure that richer channel information can be used subsequently.

[0197] Optionally, other devices use the key source and the first channel between Alice and Bob. and the second channel between Bob's end and Alice's end. Determine the confidentiality capacity This may include: other devices based on the key source and the first channel The covariance matrix, key source and second channel The covariance matrix, key source and first channel and the second channel The covariance matrix of the key source and its autocovariance matrix are used to determine the confidentiality capacity. .

[0198] In this embodiment of the application, other devices may first determine the key source and the first channel. The covariance matrix, key source and second channel The covariance matrix, key source and first channel and the second channel The four covariance matrices are: the covariance matrix of the key source, the autocovariance matrix of the key source, and so on. The confidentiality capacity is then calculated from these four covariance matrices. .

[0199] It should be noted that the timing of other devices determining the above four covariance matrices is not limited.

[0200] Optionally, other devices, based on the key source and the first channel The covariance matrix, key source and second channel The covariance matrix, key source and first channel and the second channel The covariance matrix of the key source and its autocovariance matrix are used to determine the confidentiality capacity. This may include: other devices obtaining the security capacity according to the first security capacity formula. .

[0201] The formula for the first confidentiality capacity is: ;

[0202] Indicates the confidentiality capacity; Indicates the first channel; Indicates the second channel; Indicates the key source, which is the channel. and channel One of the channels; Indicates the key source and the first channel The covariance matrix; Indicates key source and second channel The covariance matrix; Indicates key source, first channel and the second channel The covariance matrix; Represents the autocovariance matrix of the key source; This indicates the operation of taking the determinant.

[0203] Optionally, preset security capacity It is calculated based on the second confidentiality capacity formula.

[0204] The formula for the second confidentiality capacity is as follows: ;

[0205] Indicates the preset security capacity; Indicates the first channel; Indicates the second channel; Indicates the first channel The autocovariance matrix; Indicates the second channel The autocovariance matrix; Indicates the first channel Second Channel The covariance matrix; This indicates the operation of taking the determinant.

[0206] Furthermore, when the UCA antennas on Alice's and Bob's ends are ideally aligned, the transmission of each OAM mode will not interfere with each other, and the modes will have good orthogonality. In this case, the transmission in the OFDM-OAM communication system will be seamless. In the case of multiple OAM modes, the above-mentioned confidentiality capacity is for each single OAM mode. The confidentiality capacity is a linear superposition of the security capacities. Based on this, the expression for the confidentiality capacity is:

[0207] .

[0208] in, Indicates single OAM mode The corresponding first channel; Indicates single OAM mode The corresponding second channel; Indicates the first channel The autocovariance matrix; Indicates the second channel The autocovariance matrix; Indicates the first channel Second Channel The covariance matrix.

[0209] In summary, the performance of the key encoding generation method provided in the embodiments of this application will be evaluated through simulation experiments. In this simulation experiment, the carrier frequency... ;wavelength Number of elements in the UCA antenna at the transmitting end ,radius Number of elements in the UCA antenna at the receiving end ,radius The distance between Alice's end and Bob's end is The distance between Alice's end and Eve's end is The noise power is the same at the Alice, Bob, and Eve terminals.

[0210] For example, such as Figure 6 The diagram shown illustrates the relationship between security capacity and signal-to-noise ratio (SNR) according to an embodiment of this application. It should be noted that... Figure 6 This diagram also shows the comparison between the total number of different modes used in the OFDM-OAM communication system and the security capacity in the presence of an eavesdropping end (i.e., the Eve end), and the security capacity of the traditional OFDM-MIMO communication system.

[0211] from Figure 6 As can be seen, the security capacity increases with the increase of the signal-to-noise ratio (SNR), but the upward trend of the security capacity is inconsistent under different conditions.

[0212] First, when using single-mode transmission (i.e. At that time, the security capacity of the OFDM-MIMO system Significantly lower than multi-mode transmission (e.g.) , This refers to the situation where, when the UCA antennas at Alice's and Bob's ends are ideally aligned, the total security capacity of the multi-mode system is equal to the linear sum of the security capacities of each individual mode. Therefore, as... With the increase in [data / capacity], the security capacity of OFDM-OAM communication systems has increased exponentially.

[0213] Secondly, when the Eve side exists, the confidentiality capacity... Compared to the capacity of confidentiality There is some loss, but with the offset angle The increase in security capacity It is also increasing.

[0214] Finally, through comparison, it can be found that the security capacity of OFDM-MIMO communication systems... Security Capacity when using a single mode of transmission with an OFDM-OAM communication system The results of this comparison show that the modulation of a traditional OFDM communication system is essentially equivalent to a single-mode transmission in the modulation of an OFDM-OAM communication system. However, when the OFDM-OAM communication system provided in this application adopts multi-mode transmission, the security capacity of the OFDM-OAM communication system can be increased by several times compared with the security capacity of the OFDM-MIMO system.

[0215] For example, such as Figure 7The figure shows the bit error rate (BER) and offset angle provided in the embodiments of this application. A schematic diagram illustrating the relationship between the BER (Bit Error) and offset angle between the Alice and Eve ends during the encrypted communication phase. This example demonstrates this relationship through the analysis of the BER and offset angle between the Alice and Eve ends during the encrypted communication phase. The relationship is simulated.

[0216] from Figure 7 It can be seen from this that: with As the frequency increases, the BER at the Eve end becomes increasingly higher. This is partly because the UCA antennas at the Alice and Eve ends are misaligned, preventing the Eve end from demodulating the received signal (i.e., the first pilot signal), resulting in inter-mode crosstalk (OAM). Channel equalization cannot compensate for the channel-related effects, making it impossible to recover the original data. Furthermore, due to the increased frequency at the Eve end... As it grows larger, the key source (such as the channel) ) and the first channel , second channel The correlation is getting lower and lower, and Eve's end is from the channel The extracted third encryption key With the first encryption key Second encryption key The key inconsistency rate is increasing, and Eve is unable to utilize a third encryption key. The information at the Alice end is cracked to obtain the third plaintext. Under high signal-to-noise ratio conditions, the Eve segment is less affected by noise in signal reception and key generation, and the BER at the Eve end will decrease, but as... As the SNR increases, the BER tends to be around 0.5 under different SNRs, approximately at... At that time, BER did not follow As the BER increases, it changes. At this point, the BER stabilizes at around 0.5, indicating that Eve's end cannot eavesdrop on any information from the legitimate communicating parties (i.e., Alice's end and Bob's end).

[0217] Combination Figure 6 and Figure 7 Simulation results show that as the UCA antenna at the Eve end shifts by an angle... With the increase in density, the confidentiality capacity of the OFDM-OAM communication system increases, and the BER at the Eve end tends to be 0.5. Furthermore, in the key encoding generation method provided in this application embodiment, the confidentiality capacity of the OFDM-OAM communication system is increased by a factor of two, achieving extremely high confidentiality capacity, thus effectively realizing high key capacity and high security.

[0218] The key encoding generation apparatus provided in the embodiments of this application is described below. The key encoding generation apparatus described below can be referred to in correspondence with the key encoding generation method described above. The apparatus is applied to the transmitter of an OFDM-OAM communication system in industrial equipment manufacturing. The OFDM-OAM communication system also includes a receiver, which is connected to the transmitter.

[0219] Figure 8 This is a schematic diagram of the key encoding generation device provided in an embodiment of this application. For example... Figure 8 As shown, the device includes a first processing module 801 and a first transceiver module 802.

[0220] The first processing module 801 is used to generate a first pilot signal based on the first transmitted signal, and the first pilot signal is used by the receiving end to determine the first modulation signal.

[0221] The first transceiver module 802 is used to send the first pilot signal to the receiving end;

[0222] The first processing module 801 is further configured to estimate the channel between the transmitter and the receiver based on the first pilot signal and the first mediation signal transmitted by the receiver, to obtain a first channel; quantize and encode the first channel to generate a first encryption key for the transmitter during the communication phase; and determine a second mediation signal based on the second pilot signal transmitted by the receiver, wherein the second pilot signal is determined by the receiver based on the second transmission signal.

[0223] The first transceiver module 802 is also used to send the second mediation signal to the receiving end, the second mediation signal being used by the receiving end to generate a second encryption key for the receiving end during the communication phase.

[0224] Optionally, the first processing module 801 is further configured to perform error correction encoding on the transmitted plaintext data to obtain a first plaintext; determine a first ciphertext based on the first encryption key and the first plaintext; and send the first ciphertext to the receiving end, wherein the first ciphertext is used by the receiving end to decrypt the first ciphertext in conjunction with the second encryption key.

[0225] Optionally, the first transmitted signal is × dimensional data blocks, and All are integers greater than 1; the first processing module 801 is specifically used to process the first transmitted signal in the frequency domain. The OFDM signal is obtained by performing a 2D inverse fast Fourier transform (2-D IFFT) on the points with respect to the rows. This indicates the number of modulation points in the 2-D IFFT operation. The integer is greater than 1; the OFDM signal is then processed in the spatial domain. A 2-D IFFT operation on the points about the columns yields the OFDM-OAM signal. This indicates the number of antennas in the uniform circular array UCA antenna at the transmitting end. This UCA antenna is a type of UCA antenna array element. The first pilot signal is obtained by inserting a cyclic prefix into the OFDM-OAM signal and then performing up-conversion processing at the radio frequency end.

[0226] The first transceiver module 802 is specifically used to send the first pilot signal to the receiving end via a wireless channel.

[0227] Optionally, the expression for the OFDM-OAM signal is: Among them, the This indicates the OFDM-OAM signal; Represents the antenna power allocation matrix. This indicates the UCA antenna of the transmitter. The power of each antenna; express The discrete Fourier transform matrix of a point; express The discrete inverse Fourier transform matrix of a point; This indicates the first transmitted signal. express In the OAM mode, the first Data for each OAM pattern; Represents the OFDM modulation matrix; This represents the OFDM modulation matrix. The inverse matrix; This represents the discrete Fourier transform matrix. The conjugate transpose of is a type of OAM modulation matrix; Represents the OFDM modulation matrix The conjugate transpose of .

[0228] Optionally, the OAM modulation matrix The expression is: ;in, , represents the complex exponent term; Indicates by The azimuth angle of the UCA antenna array element composed of 10 antennas ; Indicates the first Number of OAM modes.

[0229] Optionally, the expression for the first pilot signal transmitted through the wireless channel is: ; This indicates the first pilot signal; This indicates the number of antennas in the uniform circular array (UCA) antenna of the transmitter. This indicates the number of modulation points in the 2-D IFFT operation; The channel matrix represents the wireless channel; Represents the antenna power allocation matrix. This indicates the UCA antenna at the transmitting end. The power of each antenna; express The discrete Fourier transform matrix of a point; This represents the discrete Fourier transform matrix. The conjugate transpose of is a type of OAM modulation matrix; This indicates the first transmitted signal. express In the OAM mode, the first Data for each OAM pattern; Represents the OFDM modulation matrix; Represents the OFDM modulation matrix The conjugate transpose of ; This indicates that the mean is zero and the variance is... The complex Gaussian white noise matrix satisfies , express An identity matrix of order 1.

[0230] Optionally, the first processing module 801 is specifically used to obtain the first ciphertext according to the encryption formula; wherein the encryption formula is: ; This indicates the first ciphertext; This indicates the first plaintext; This indicates the first encryption key; This indicates the XOR operation.

[0231] The key encoding generation apparatus provided in the embodiments of this application is described below. The key encoding generation apparatus described below can be referred to in correspondence with the key encoding generation method described above. The apparatus is applied to the receiver end of the OFDM-OAM communication system in industrial equipment manufacturing. The OFDM-OAM communication system also includes a transmitter end, which is connected to the receiver end.

[0232] Figure 9 This is a schematic diagram of the key encoding generation device provided in an embodiment of this application. For example... Figure 9 As shown, the device includes: a second processing module 901 and a second transceiver module 902.

[0233] The second processing module 901 is used to determine a first modulation signal based on the first pilot signal sent by the transmitter, wherein the first pilot signal is determined by the transmitter based on the first transmission signal;

[0234] The second transceiver module 902 is used to send the first mediation signal to the transmitter, and the first mediation signal is used by the transmitter to generate the first encryption key of the transmitter in the communication phase.

[0235] The second processing module 901 is also used to generate a second pilot signal based on the second transmitted signal;

[0236] The second transceiver module 902 is also used to send the second pilot signal to the transmitter, and the second pilot signal is used by the transmitter to determine the second modulation signal;

[0237] The second processing module 901 is further configured to estimate the channel between the receiver and the transmitter based on the second pilot signal and the second mediation signal sent by the transmitter, to obtain a second channel; and to quantize and encode the second channel to generate a second encryption key for the receiver during the communication phase.

[0238] Optionally, the second processing module 901 is further configured to perform OFDM-OAM demodulation on the first ciphertext sent by the transmitter to obtain a second ciphertext, wherein the first ciphertext is determined by the transmitter based on the first encryption key and the transmitted plaintext; decrypt the second ciphertext based on the second encryption key to obtain a second plaintext; and decode and correct the second plaintext to obtain a third plaintext.

[0239] Optionally, the second processing module 901 is specifically used to receive the first pilot signal transmitted by the transmitter through a wireless channel. The first pilot signal is obtained by the transmitter performing a two-dimensional inverse fast Fourier transform (2-DIFFT) operation on the first transmitted signal. The first pilot signal is first down-converted at the radio frequency end and then the cyclic prefix is ​​removed at the baseband end to obtain the processed first pilot signal. The processed first pilot signal is then subjected to a two-dimensional fast Fourier transform (2-DFFT) operation to obtain the first modulation signal.

[0240] Optionally, the expression for the first mediation signal is: ;in, This indicates the first mediation signal; express The first of the sub-modulation signals Individual adjustment signals.

[0241] Optionally, the channel matrix of the wireless channel The expression is: = ;in, Indicates the first The number of launch elements to the first The channel gain between the receiving array elements, the first The first transmitting element is an element in the UCA antenna of the transmitting end. Each receiving element is an element in the UCA antenna of the receiving end; This represents a constant related to signal attenuation; Indicates the wavelength of the OAM signal; Indicates the first The first launch element to the first The transmission distance between each receiving array element.

[0242] Optionally, the transmission distance The expression is: Among them, the first The three-dimensional coordinate system of each transmitting element at the transmitting end The coordinates below are , This indicates the radius of the UCA antenna array element at the transmitting end; Indicates the first The azimuth angle of each transmitting element in the UCA antenna at the transmitting end; Each receiving array element in this three-dimensional coordinate system The coordinates below are , , Indicates the relationship with this three-dimensional coordinate system The parallel three-dimensional coordinate system of the receiving end Around The rotation angle of the shaft, Indicates the first The azimuth angle of each receiving element in the UCA antenna at the receiving end. This indicates the three-dimensional coordinate system With this three-dimensional coordinate system The distance between the origin points.

[0243] Optionally, the second processing module 901 is specifically used to obtain the second plaintext according to the decryption formula; wherein the decryption formula is: ; This indicates the second plaintext; This indicates the second ciphertext; This indicates the second encryption key; This indicates the XOR operation.

[0244] Figure 10 This is a schematic diagram of the structure of the electronic device provided in an embodiment of this application. For example... Figure 10As shown, the electronic device may include a processor 1010, a communications interface 1020, a memory 1030, and a communication bus 1040. The processor 1010, communications interface 1020, and memory 1030 communicate with each other via the communication bus 1040. The processor 1010 can call logical instructions in the memory 1030 to execute a key encoding generation method. This method is applied to the transmitter end of an OFDM-OAM communication system in industrial equipment manufacturing, where the OFDM-OAM communication system also includes a receiver end. Alternatively, the method is applied to the receiver end of an OFDM-OAM communication system in industrial equipment manufacturing.

[0245] Furthermore, the logical instructions in the aforementioned memory 1030 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0246] On the other hand, embodiments of this application also provide a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the key encoding generation method provided by the above methods. The method is applied to the transmitter of an OFDM-OAM communication system in industrial equipment manufacturing, or the method is applied to the receiver of an OFDM-OAM communication system in industrial equipment manufacturing.

[0247] In another aspect, embodiments of this application also provide a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the key encoding generation method provided by the above methods. The method is applied to a transmitter in an OFDM-OAM communication system in industrial equipment manufacturing, or the method is applied to a receiver in an OFDM-OAM communication system in industrial equipment manufacturing.

[0248] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0249] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0250] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A key encoding generation method, characterized in that, An orthogonal frequency division multiplexing-orbit angular momentum (OFDM-OAM) communication system applied in industrial equipment manufacturing includes a transmitter, and the OFDM-OAM communication system further includes a receiver connected to the transmitter; the method includes: Based on the first transmitted signal, a first pilot signal is generated; and the first pilot signal is sent to the receiving end. The first pilot signal is used by the receiving end to determine a first modulation signal. The process of determining the first modulation signal is as follows: the receiving end first performs down-conversion processing on the first pilot signal at the radio frequency end, and then removes the cyclic prefix at the baseband end to obtain the processed first pilot signal. The receiving end performs a two-dimensional fast Fourier transform (2-D FFT) operation on the processed first pilot signal to obtain the first modulation signal. Based on the first pilot signal and the first mediation signal sent by the receiving end, the channel between the transmitting end and the receiving end is estimated to obtain the first channel; The first channel is quantized and encoded to generate the first encryption key for the transmitting end during the communication phase; The second pilot signal transmitted by the receiving end is first down-converted at the radio frequency end, and then the cyclic prefix is ​​removed at the baseband end to obtain the processed second pilot signal; the processed second pilot signal is subjected to a 2-D FFT operation to obtain a second mediation signal, which is determined by the receiving end based on the second transmitted signal; and the second mediation signal is sent to the receiving end, which is used by the receiving end to generate the second encryption key for the receiving end during the communication phase.

2. The key encoding generation method according to claim 1, characterized in that, The method further includes: Error-correcting encoding is performed on the transmitted plaintext data to obtain the first plaintext; Based on the first encryption key and the first plaintext, a first ciphertext is determined; and the first ciphertext is sent to the receiving end, wherein the first ciphertext is used by the receiving end to decrypt the first ciphertext in conjunction with the second encryption key.

3. The key encoding generation method according to claim 1, characterized in that, The first transmitted signal is × dimensional data blocks, and All are integers greater than 1; the first pilot signal is generated based on the first transmitted signal; And send the first pilot signal to the receiving end, including: The first transmitted signal is processed in the frequency domain. The OFDM signal is obtained by performing a 2D inverse fast Fourier transform (2-D IFFT) on the points with respect to the rows. This represents the number of modulation points in the 2-D IFFT operation. It is an integer greater than 1; The OFDM signal is then processed in the spatial domain. A 2-D IFFT operation on the points about the columns yields the OFDM-OAM signal. This indicates the number of antennas in the uniform circular array UCA antenna at the transmitting end, where the UCA antenna is a type of UCA antenna array element. It is an integer greater than 1; A cyclic prefix is ​​inserted into the OFDM-OAM signal, and then it undergoes up-conversion processing at the radio frequency end to obtain the first pilot signal; the first pilot signal is then transmitted to the receiving end via a wireless channel.

4. The key encoding generation method according to claim 3, characterized in that, The expression for the OFDM-OAM signal is: ; Among them, the This refers to the OFDM-OAM signal; Represents the antenna power allocation matrix. The UCA antenna of the transmitting end represents the first... The power of each antenna; express The discrete Fourier transform matrix of a point; express The discrete inverse Fourier transform matrix of a point; This indicates the first transmitted signal. express In the OAM mode, the first Data for each OAM pattern; Represents the OFDM modulation matrix; Represents the OFDM modulation matrix The inverse matrix; The discrete Fourier transform matrix represents... The conjugate transpose of is a type of OAM modulation matrix; Represents the OFDM modulation matrix The conjugate transpose of .

5. The key encoding generation method according to claim 3, characterized in that, The expression for the first pilot signal transmitted through the wireless channel is: ； This represents the first pilot signal; This indicates the number of antennas in the uniform circular array (UCA) antenna at the transmitting end; This represents the number of modulation points in the 2-D IFFT operation; The channel matrix represents the wireless channel; Represents the antenna power allocation matrix. This indicates the UCA antenna at the transmitting end. The power of each antenna; express The discrete Fourier transform matrix of a point; The discrete Fourier transform matrix represents... The conjugate transpose of is a type of OAM modulation matrix; This indicates the first transmitted signal. express In the OAM mode, the first Data for each OAM pattern; Represents the OFDM modulation matrix; Represents the OFDM modulation matrix The conjugate transpose of ; This indicates that the mean is zero and the variance is... The complex Gaussian white noise matrix satisfies , express An identity matrix of order 1.

6. A key encoding generation method, characterized in that, An orthogonal frequency division multiplexing-orbit angular momentum (OFDM-OAM) communication system applied in industrial equipment manufacturing includes a receiver, and the OFDM-OAM communication system further includes a transmitter connected to the receiver; the method includes: The first pilot signal transmitted by the transmitting end is first down-converted at the radio frequency end, and then the cyclic prefix is ​​removed at the baseband end to obtain the processed first pilot signal; the processed first pilot signal is subjected to a two-dimensional fast Fourier transform (2-D FFT) operation to obtain a first mediation signal, which is determined by the transmitting end based on the first transmitted signal; and the first mediation signal is sent to the transmitting end, which is used by the transmitting end to generate the first encryption key for the transmitting end during the communication phase; A second pilot signal is generated based on the second transmitted signal; and the second pilot signal is sent to the transmitting end. The second pilot signal is used by the transmitting end to determine the second modulation signal. The process of determining the second modulation signal is as follows: the transmitting end first performs down-conversion processing on the second pilot signal at the radio frequency end, and then removes the cyclic prefix at the baseband end to obtain the processed second pilot signal. The transmitting end performs a 2-D FFT operation on the processed second pilot signal to obtain the second modulation signal. Based on the second pilot signal and the second mediation signal sent by the transmitter, the channel between the receiver and the transmitter is estimated to obtain the second channel; The second channel is quantized and encoded to generate a second encryption key for the receiving end during the communication phase.

7. The key encoding generation method according to claim 6, characterized in that, The method further includes: OFDM-OAM demodulation is performed on the first ciphertext sent by the transmitting end to obtain the second ciphertext. The first ciphertext is determined by the transmitting end based on the first encryption key and the plaintext of the transmitted data. The second ciphertext is decrypted using the second encryption key to obtain the second plaintext; The second plaintext is decoded and error-corrected to obtain the third plaintext.

8. The key encoding generation method according to claim 6, characterized in that, The method further includes: The first pilot signal transmitted by the transmitter is received through a wireless channel. The first pilot signal is obtained by the transmitter performing a two-dimensional inverse fast Fourier transform (2-D IFFT) operation on the first transmitted signal.

9. The key encoding generation method according to claim 8, characterized in that, The expression for the first mediation signal is: ； in, This indicates the first mediation signal; express The first of the sub-modulation signals Individual adjustment signals.

10. The key encoding generation method according to claim 9, characterized in that, The channel matrix of the wireless channel The expression is: = ； in, Indicates the first The number of launch elements to the first The channel gain between the receiving array elements, the first The transmitting element is an element in the UCA antenna of the transmitting end, the first transmitting element is... Each receiving element is an element in the UCA antenna of the receiving end; This represents a constant related to signal attenuation; Indicates the wavelength of the OAM signal; Indicates the first The first transmitting element to the first The transmission distance between each receiving array element.

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