CN118509103B - Communication system, communication method, device, communication equipment, storage medium and product - Google Patents

Abstract

The present application relates to a communication system, a communication method, an apparatus, a communication device, a storage medium and a product. The communication system includes a signal source, a backscatter tag, a receiving end and an eavesdropping end; wherein: the signal source is used to send a radio frequency signal; the backscatter tag is used to send the radio frequency signal and an interference signal; the receiving end is used to receive a combined signal and identify the radio frequency signal from the combined signal; the combined signal includes a radio frequency signal and an interference signal; the eavesdropping end is used to receive the combined signal. It can be seen that in the communication system proposed in the embodiment of the present application, the interference signal is artificially sent while the radio frequency signal is sent by the backscatter tag, so as to reduce the signal-to-noise ratio of the radio frequency signal received by the eavesdropping end, thereby achieving confidential communication and improving the anti-eavesdropping performance of the communication system.

Description

Communication system, communication method, device, communication equipment, storage medium and product

Technical Field

The present application relates to the field of communication technology, and in particular to a communication system, communication method, apparatus, communication equipment, storage medium and product.

Background Art

With the development of communication technology and Internet of Things technology, the application of passive Internet of Things devices (such as passive tags) in the field of Internet of Things communication is becoming more and more common. Among them, backscatter technology is the core technology for passive Internet of Things devices to communicate; for example: traditional single-station backscatter communication, bistatic backscatter communication, ambient backscatter communication (AmBC), etc.

At present, in the process of information transmission in the communication system applied to the above communication technology, there is a phenomenon that illegal eavesdroppers eavesdrop on the message signals sent by the backscatter communication tags, which brings great challenges to the secure transmission of information.

Therefore, how to improve the anti-eavesdropping performance of the above communication system has become a technical problem that needs to be solved urgently.

Summary of the invention

Based on this, it is necessary to provide a communication system, communication method, apparatus, communication equipment, computer-readable storage medium and computer program product that can improve the anti-eavesdropping performance of a communication system based on reflection scattering in order to address the above technical problems.

In a first aspect, the present application provides a communication system, which includes: a signal source, a backscatter tag, a receiving end, and an eavesdropping end; wherein:

A signal source, used for sending a radio frequency signal;

A backscatter tag for transmitting the radio frequency signal and the interference signal;

A receiving end, used for receiving a combined signal and identifying a radio frequency signal from the combined signal; the combined signal includes a radio frequency signal and an interference signal;

The eavesdropping end is used to receive the combined signal.

In one of the embodiments, a first antenna and a second antenna are provided on the backscatter tag;

A backscatter tag is used to forward the radio frequency signal through the first antenna and send an interference signal through the second antenna.

In one embodiment, the signal source includes a carrier generator, and the distance between the signal source and the backscatter tag is less than a preset distance threshold.

In one of the embodiments, the backscatter tag is also used to convert the radio frequency signal into energy for power supply.

In one of the embodiments, the receiving end is specifically used to receive the radio frequency signal and the interference signal sent by the backscatter tag, and receive the radio frequency signal sent by the signal source.

In one of the embodiments, the eavesdropping end is specifically used to receive the radio frequency signal and the interference signal sent by the backscatter tag, and receive the radio frequency signal sent by the signal source.

In one of the embodiments, the communication system further includes: a control device;

A control device, used to adjust the configuration parameters of the target device so that the target device performs signal transmission based on the adjusted configuration parameters;

The target device includes a signal source and/or a backscatter tag, and the configuration parameters include a signal beam vector of the signal source and/or a power of the backscatter tag.

In a second aspect, the present application provides a communication method, which is applied to the communication system in the first aspect, and the method includes:

The signal source sends a radio frequency signal;

Backscatter tags send RF signals and interference signals;

The receiving end receives the combined signal and identifies the radio frequency signal from the combined signal; the combined signal includes the radio frequency signal and the interference signal;

The eavesdropping end receives the combined signal.

In a third aspect, the present application provides a communication method, which is applied to the communication system in the first aspect, and the method includes:

Adjusting the configuration parameters of the target device so that the target device performs signal transmission based on the adjusted configuration parameters;

The target device includes a signal source and/or a backscatter tag, and the configuration parameters include a signal beam vector of the signal source and/or a power of the backscatter tag.

In one embodiment, adjusting the configuration parameters of the target device includes:

Based on the initial optimization function corresponding to the confidentiality capacity of the communication system, a target optimization function is constructed;

Taking the target optimization function as the maximum principle, the target configuration parameters are determined by solving the target optimization function;

Adjust the configuration parameters of the target device according to the target configuration parameters.

In one embodiment, constructing a target optimization function based on an initial optimization function corresponding to the confidentiality capacity of the communication system includes:

Extracting the real number expression of the logarithmic function from the initial optimization function corresponding to the confidentiality capacity of the communication system to obtain the target real number expression;

Construct a target optimization function based on the target true number expression.

In one embodiment, constructing a target optimization function based on a target true number expression includes:

The target optimization function is obtained by performing concave-convex transformation on the uncertain fractions in the target real number expression.

In one embodiment, a concave-convex conversion is performed on a fraction with uncertain concave-convexity in a target real number expression to obtain a target optimization function, including:

Convert the target true number expression into an intermediate optimization function;

The uncertain fractions in the intermediate optimization function are transformed into convex and concave ones to obtain the target optimization function.

In one embodiment, the target optimization function is taken as the maximum principle, and the target configuration parameters are determined by solving the target optimization function, including:

The obtained distance value between every two devices in the communication system, the noise power of the receiving end, and the noise power of the eavesdropping end;

Taking the target optimization function as the maximum principle, the signal beam vector of the signal source and the power of the backscatter tag as iterative variables, the distance value between every two devices in the communication system, the noise power of the receiving end, and the noise power of the eavesdropping end are substituted into the target optimization function for iterative calculation to obtain the target configuration parameters.

In a fourth aspect, the present application further provides a communication device, applied to the communication system in the first aspect, the device comprising:

An adjustment module, used to adjust the configuration parameters of the target device so that the target device performs signal transmission based on the adjusted configuration parameters;

The target device includes a signal source and/or a backscatter tag, and the configuration parameters include a signal beam vector of the signal source and/or a power of the backscatter tag.

In a fifth aspect, the present application further provides a communication device, the communication device comprising: a memory, a transceiver, and a processor:

A memory for storing a computer program; a transceiver for transmitting and receiving data under the control of a processor; and a processor for reading the computer program in the memory and executing the communication method in the third aspect.

In a sixth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the communication method in the third aspect above.

In a seventh aspect, the present application further provides a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of the communication method in the third aspect above.

The above-mentioned communication system, communication method, apparatus, communication equipment, storage medium and computer program product, the communication system includes a signal source, a backscatter tag, a receiving end and an eavesdropping end; wherein: the signal source is used to send a radio frequency signal; the backscatter tag is used to send the radio frequency signal and an interference signal; the receiving end is used to receive a combined signal and identify the radio frequency signal from the combined signal; the combined signal includes a radio frequency signal and an interference signal; the eavesdropping end is used to receive the combined signal. It can be seen that in the communication system proposed in the embodiment of the present application, the interference signal is artificially sent while the radio frequency signal is sent by the backscatter tag, so as to reduce the signal-to-noise ratio of the radio frequency signal received by the eavesdropping end, thereby achieving confidential communication and improving the anti-eavesdropping performance of the communication system.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic diagram of the structure of a communication system in one embodiment;

FIG2 is a schematic diagram of the structure of a backscatter tag in one embodiment;

FIG3 is a schematic diagram of a flow chart of a communication method in one embodiment;

FIG4 is a schematic diagram of a flow chart of a communication method in one embodiment;

FIG5 is a schematic diagram of the structure of a communication system in one embodiment;

FIG6 is a schematic diagram of a process for optimizing confidentiality capacity in one embodiment;

FIG7 is a schematic diagram of simulation results in one embodiment;

FIG8 is a structural block diagram of a communication device in one embodiment.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

With the development of communication technology and Internet of Things technology, the application of passive Internet of Things devices (such as passive tags) in the field of Internet of Things communication is becoming more and more common. Among them, backscatter technology is the core technology for passive Internet of Things devices to communicate; for example: traditional single-station backscatter communication, bistatic backscatter communication, ambient backscatter communication (AmBC), etc.

For example, bistatic backscatter communication is an emerging communication technology mainly used in Internet of Things (IoT) networks. This communication method has become popular due to its low cost and low power consumption, and has become a key technology for the success of IoT. Bistatic backscatter communication can effectively reduce path loss by setting a carrier generator near the tag, thereby expanding the transmission range between the tag and the reader.

At present, in the process of information transmission in the communication system applied to the above communication technology, there is a phenomenon that illegal eavesdroppers eavesdrop on the message signals sent by the backscatter communication tags, which brings great challenges to the secure transmission of information. In the related technology, the legal receiver of full-duplex can actively emit artificial noise to suppress the communication performance of the eavesdropper, but this method will cause noise interference to the legal receiver, and the legal receiver needs to have the ability to emit artificial noise interference to achieve the anti-eavesdropping function.

Based on this, in response to the challenges brought by the above-mentioned backscatter communication eavesdropping problem to communication security, in order to ensure the secure transmission of information, when the channel state information (CSI) of the legitimate receiver and the illegal eavesdropper is known, the embodiment of the present application proposes an anti-eavesdropping communication system that ensures the physical layer security of the legitimate receiver, and improves the anti-eavesdropping performance of the communication system by artificially sending interference signals through reflective tags, thereby ensuring the secure transmission of information.

On the other hand, for traditional communication systems, in ideal scenarios, the beam vector of the transmitter and the signal power reflected by the tag remain unchanged, that is, the confidentiality capacity of the communication system cannot be changed, resulting in low transmission performance of the communication system; among them, confidentiality capacity refers to the maximum confidentiality transmission performance limit that can be theoretically achieved using confidentiality transmission technology under a specific wireless channel environment.

Based on this, the embodiment of the present application also proposes an optimization method for maximizing the confidentiality capacity of a backscatter communication system, which can improve the confidentiality capacity of the communication system while ensuring communication security, thereby improving the transmission performance of the communication system.

The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

Fig. 1 is a schematic diagram of the structure of the communication system provided by the embodiment of the present application. As shown in Fig. 1, the communication system includes a signal source 11, a backscatter tag 12, a receiving end 13 and an eavesdropping end 14; wherein: the signal source 11 is used to send a radio frequency signal; the backscatter tag 12 is used to send the radio frequency signal and an interference signal; the receiving end 13 is used to receive a combined signal and identify the radio frequency signal from the combined signal; the combined signal includes a radio frequency signal and an interference signal; the eavesdropping end 14 is used to receive the combined signal.

Exemplarily, the communication system may include, but is not limited to, a series of new backscatter communication systems such as a single-station backscatter system, a dual-station backscatter system, an environmental backscatter system, a full-duplex-based backscatter system, and a full-signal backscatter system. The embodiment of the present application does not specifically limit the type of the communication system. Accordingly, the signal source 11 can be adaptively set according to the type of the communication system. For example, when the communication system is an environmental backscatter system, the signal source 11 can be an environmental signal source; when the communication system is a dual-station backscatter system, the signal source 11 can be a carrier generator near the backscatter tag 12, that is, the distance between the signal source 11 and the backscatter tag 12 should be less than the preset distance threshold.

Exemplarily, the signal source 11 can be used to send a radio frequency signal, which can be a message signal carrying information; the backscatter tag 12 can receive the radio frequency signal and reflect the radio frequency signal; in this example, in order to prevent the eavesdropping end from eavesdropping on the radio frequency signal emitted by the backscatter tag 12, the backscatter tag 12 can also send an interference signal while reflecting the radio frequency signal, that is, the interference signal is artificially sent by the backscatter tag to reduce the signal-to-noise ratio of the radio frequency signal received by the illegal eavesdropping end, thereby achieving confidential communication.

Exemplarily, when sending the radio frequency signal and the interference signal, the backscatter tag 12 may send the radio frequency signal and the interference signal separately, or may fuse the radio frequency signal and the interference signal and then send them mixedly.

In an optional implementation, as shown in FIG2 , the backscatter tag 12 may be provided with a first antenna 121 and a second antenna 122; the backscatter tag 12 may forward the radio frequency signal through the first antenna 121, and send the interference signal through the second antenna 122. Of course, the backscatter tag 12 may also send the interference signal through the first antenna 121, and forward the radio frequency signal through the second antenna 122.

In another optional implementation, when the backscatter tag 12 receives a radio frequency signal, it can also automatically generate an interference signal, and fuse the received radio frequency signal with the interference signal, and then send the fused signal through the antenna in the backscatter tag 12. Exemplarily, for this method, the backscatter tag 12 can be a single-antenna tag or a multi-antenna tag; when the backscatter tag 12 is a multi-antenna tag, the backscatter tag 12 can send the fused signal through any one of the antennas, or send the mixed signal through multiple antennas, etc.

In addition, it should be noted that when generating an interference signal, the backscatter tag 12 can generate the same interference signal according to fixed signal parameters, or generate different interference signals according to preset signal rules, or generate different interference signals according to relevant parameters of the radio frequency signal, etc.; that is, when the backscatter tag 12 forwards different radio frequency signals, the interference signals sent synchronously can be the same or different; the embodiments of the present application do not limit this.

In addition, for passive tags, they can convert the radio frequency energy emitted by the outside world into a DC power supply to power the circuit inside the tag. On this basis, the backscatter tag 12 in this embodiment can also convert the received radio frequency signal into energy for power supply.

After the backscatter tag 12 sends the RF signal and the interference signal, the receiving end 13 can receive a combined signal including the RF signal and the interference signal; illustratively, in the communication system, the receiving end 13 can obtain the interference signal in advance, and on this basis, when the combined signal is received, the RF signal can be identified from the combined signal, and the interference signal can be separated, thereby obtaining useful information transmitted by the signal source. As for the eavesdropping end 14, it can also receive a combined signal including the RF signal and the interference signal, but because the signal-to-noise ratio of the combined signal is low, and the eavesdropping end 14 does not know the interference signal in advance, it is difficult to identify the useful RF signal from the combined signal, so as to achieve safe transmission of information.

The above-mentioned communication system includes a signal source, a backscatter tag, a receiving end and an eavesdropping end; wherein: the signal source is used to send a radio frequency signal; the backscatter tag is used to send the radio frequency signal and an interference signal; the receiving end is used to receive a combined signal and identify the radio frequency signal from the combined signal; the combined signal includes a radio frequency signal and an interference signal; the eavesdropping end is used to receive the combined signal. It can be seen that in the communication system proposed in the embodiment of the present application, the backscatter tag artificially sends an interference signal while sending the radio frequency signal, so as to reduce the signal-to-noise ratio of the radio frequency signal received by the eavesdropping end, thereby achieving confidential communication and improving the anti-eavesdropping performance of the communication system.

In an exemplary embodiment, the receiving end 13 may receive the RF signal and the interference signal sent from the backscatter tag 12, and may also receive the RF signal sent from the signal source 11 when receiving the combined signal; that is, the combined signal may include the RF signal and the interference signal sent from the backscatter tag 12, and the RF signal sent from the signal source 11. Similarly, the eavesdropping end 14 may also receive the RF signal and the interference signal sent from the backscatter tag 12, and may also receive the RF signal sent from the signal source 14 when receiving the combined signal.

In an exemplary embodiment, the above-mentioned communication system may further include a control device, which may be used to adjust the configuration parameters of the target device so that the target device transmits signals based on the adjusted configuration parameters; wherein the target device may include a signal source and/or a backscatter tag, and accordingly, the configuration parameters may include a signal beam vector of the signal source and/or the power of the backscatter tag.

That is to say, for the above-mentioned communication system, in order to achieve a larger signal capacity, only the signal beam vector of the signal source in the communication system may be adjusted, or only the power of the backscatter tag in the communication system may be adjusted, or both the signal beam vector of the signal source in the communication system and the power of the backscatter tag in the communication system may be adjusted, that is, the signal beam vector of the signal source and the power of the backscatter tag may be adjusted at the same time to achieve a larger signal capacity, so that the communication system can transmit information with greater confidentiality transmission performance, thereby improving the transmission performance of the communication system.

Exemplarily, the control device can determine the signal beam vector of the signal source and the power of the backscatter tag corresponding to the maximum confidentiality capacity by optimizing the confidentiality capacity expression of the communication system, thereby dynamically adjusting the signal beam vector of the signal source and/or the power of the backscatter tag, so that the signal source can send the radio frequency signal with the adjusted signal beam vector, and/or the backscatter tag can send the radio frequency signal and the interference signal with the adjusted power.

Exemplarily, in the case where the backscatter tag includes a first antenna and a second antenna, the power of the backscatter tag may include the transmit power of the first antenna and the transmit power of the second antenna, so that the first antenna can transmit the radio frequency signal with the adjusted transmit power, and the second antenna can transmit the interference signal with the adjusted transmit power. It should be noted that the transmit power of the first antenna and the transmit power of the second antenna may be the same or different.

In this embodiment, the signal beam vector of the signal source in the communication system and/or the power of the backscatter tag can be dynamically adjusted to ensure that the communication system always communicates with the maximum signal capacity, thereby improving the transmission performance of the communication system.

In an exemplary embodiment, as shown in FIG3 , a communication method is provided, which is described by taking the method applied to the communication system in any of the above embodiments as an example, and includes the following steps, wherein:

Step 301: a signal source sends a radio frequency signal.

Step 302: The backscatter tag sends a radio frequency signal and an interference signal.

Step 303: The receiving end receives the combined signal and identifies the radio frequency signal from the combined signal; the combined signal includes the radio frequency signal and the interference signal.

Step 304: the eavesdropping end receives the combined signal.

By adopting this communication method, when the signal source sends a radio frequency signal to the receiving end through a backscattering tag, an interference signal is artificially sent through the backscattering tag to reduce the signal-to-noise ratio of the radio frequency signal received by the illegal receiving end, thereby achieving confidential transmission and improving the anti-eavesdropping performance of the communication system.

It should be noted that the specific implementation of the communication method can refer to the relevant content description in each embodiment of the above-mentioned communication system, and will not be repeated here.

In an exemplary embodiment, as shown in FIG. 4 , a communication method is provided, which is described by taking the method applied to the communication system in any of the above embodiments as an example, for example, the method can be applied to a control device in the communication system, and can also be applied to other devices in the communication system, etc.; the method includes the following steps, wherein:

Step 401, adjust the configuration parameters of the target device so that the target device transmits signals based on the adjusted configuration parameters; wherein the target device includes a signal source and/or a backscatter tag, and the configuration parameters include a signal beam vector of the signal source and/or a power of the backscatter tag.

Exemplarily, in the case where the backscatter tag includes multiple antennas, the power of the backscatter tag may include the transmission power of each antenna; for example: for the backscatter tag structure shown in Figure 2 above, the backscatter tag may include a first antenna and a second antenna, and accordingly, the power of the backscatter tag may include the transmission power of the first antenna and the transmission power of the second antenna.

Exemplarily, when adjusting the configuration parameters of the target device, the parameter values of the configuration parameters of the target device may be determined first, and then the configuration parameters of the target device may be adjusted according to the determined parameter values of the configuration parameters of the target device.

Optionally, a target optimization function can be constructed based on the initial optimization function corresponding to the confidentiality capacity of the communication system; and the target optimization function is used as the maximum principle to determine the target configuration parameters by solving the target optimization function; and then, the configuration parameters of the target device are adjusted according to the target configuration parameters. Among them, the initial optimization function of the confidentiality capacity can be an optimization function determined based on the relevant communication parameters of the communication system and the calculation expression of the confidentiality capacity; the target optimization function can be an optimization function obtained by deforming or transforming the initial optimization function; for example: the convexity of the initial optimization function is transformed to obtain a convex optimization function as the target optimization function; for example: some functions in the initial optimization function are extracted as the target optimization function, etc.

It should be noted that when determining the target optimization function based on the initial optimization function, at least one deformation and/or transformation can be used to obtain the target optimization function. The embodiment of the present application does not specifically limit the method for determining the target optimization function.

In the above communication method, the configuration parameters of the target device in the communication system are adjusted so that the target device transmits signals based on the adjusted configuration parameters; wherein the target device includes a signal source and/or a backscattering tag in the communication system, and the configuration parameters include a signal beam vector of the signal source and/or the power of the backscattering tag. By adopting this communication method, not only can the backscattering tag artificially send an interference signal while sending a radio frequency signal, so as to reduce the signal-to-noise ratio of the radio frequency signal received by the eavesdropping end, thereby achieving confidential communication and improving the anti-eavesdropping performance of the communication system; but also by optimizing the confidentiality capacity of the communication system and dynamically adjusting the signal beam vector of the signal source and/or the power of the backscattering tag in the communication system, it is ensured that the communication system always communicates with the maximum signal capacity, thereby improving the transmission performance of the communication system.

In an exemplary embodiment, when the initial optimization function of the confidentiality capacity includes a logarithmic function, it is relatively complicated to directly solve the logarithmic function, and the internal fraction of the logarithmic function, that is, the real part of the logarithmic function and the original logarithmic function satisfy the function property of increasing and decreasing together. Therefore, when optimizing the logarithmic function, a new target optimization function can be constructed based on the internal fraction of the logarithmic function. Based on this, the above-mentioned construction of the target optimization function based on the initial optimization function corresponding to the confidentiality capacity of the communication system may include:

The true number expression of the logarithmic function is extracted from the initial optimization function corresponding to the confidentiality capacity of the communication system to obtain the target true number expression; and the target optimization function is constructed based on the target true number expression.

Exemplarily, when the target real number expression is a non-convex problem, since non-convex problems are difficult to solve using traditional convex optimization methods, such as Newton's method, gradient descent method, etc., for non-convex target real number expressions, when constructing a target optimization function based on the target real number expression, the fraction with uncertain concavity and convexity in the target real number expression can also be converted into concavity and convexity to obtain the target optimization function. In other words, the fraction with uncertain concavity and convexity in the target real number expression is converted into a concavity and convexity to obtain the converted fraction corresponding to the fraction; then, the target optimization function is constructed based on the converted fraction and other fractions in the target real number expression.

Exemplarily, when performing a concave-convex conversion on the uncertain fraction in the target true number expression to obtain the target optimization function, the target true number expression can also be first converted into an intermediate optimization function, that is, the expression is converted into a function form, and then the uncertain fraction in the intermediate optimization function is further converted into a concave-convex conversion to obtain the target optimization function. For example, the target true number expression can be equal to an unknown parameter, and then the equation can be converted into a function form for solving the unknown parameter, that is, the intermediate optimization function is obtained.

Furthermore, the above-mentioned determination of target configuration parameters by solving the target optimization function with the target optimization function as the maximum principle may include:

The distance value between every two devices in the communication system, the noise power of the receiving end, and the noise power of the eavesdropping end are obtained; taking the target optimization function as the maximum principle, the signal beam vector of the signal source and the power of the backscattering tag are taken as iterative variables, and the distance value between every two devices in the communication system, the noise power of the receiving end, and the noise power of the eavesdropping end are substituted into the target optimization function for iterative calculation to obtain the target configuration parameters.

That is to say, for the communication system, the preset communication parameters of the communication system can be obtained first, and the preset communication parameters can include multiple parameters required for calculating the confidentiality capacity of the communication system, such as the channel gain between each device, the noise power of the receiving end, and the noise power of the eavesdropping end; wherein the channel gain between devices can be calculated by the distance value between the devices. It should be noted that the preset communication parameters do not include variable parameters that need to be optimized, that is, they do not include the signal beam vector of the signal source and the power of the backscatter tag.

Next, the preset communication parameters of the communication system are substituted into the target optimization function to obtain the target optimization function for calculating the iterative variables. Then, taking the target optimization function as the maximum principle, the target optimization function is iteratively calculated under the preset constraints to obtain the target configuration parameters of the communication system. The target configuration parameters include the signal beam vector of the signal source and the power of the backscatter tag.

In this embodiment, the real number expression in the logarithmic function of the confidentiality capacity is extracted to construct an intermediate optimization function, and the target optimization function of the confidentiality capacity is obtained by performing a concave-convex conversion on the uncertain fraction in the intermediate optimization function; then, the preset communication parameters of the communication system are substituted into the target optimization function to form a target optimization function for solving the signal beam vector of the signal source and the power of the backscatter tag, and then iterative calculation is performed based on the target optimization function as the maximum principle to obtain the signal beam vector of the signal source and the power of the backscatter tag corresponding to the maximum confidentiality capacity, so as to adjust the signal beam vector of the signal source in the communication system and adjust the power of the backscatter tag; thereby, the communication system communicates at the maximum confidentiality capacity at all times, thereby improving the transmission performance of the communication system.

The following takes the channel of the communication system as the Ruili fading channel as an example to optimize the confidentiality capacity of the communication system. Referring to Figure 5, it shows a structural model of a communication system, which includes a multi-antenna signal source for sending a radio frequency signal s(n), which can be a sinusoidal signal; a dual-antenna backscattering tag for reflecting the radio frequency signal of the signal source, wherein the first antenna sends a radio frequency signal c(n) and the second antenna sends an interference signal x(n); a single-antenna legal receiving end for receiving the radio frequency signal from the backscattering tag and being able to demodulate the interference signal; and a single-antenna illegal eavesdropping end for eavesdropping the radio frequency signal reflected by the backscattering tag, but being unable to demodulate the interference signal.

When constructing the initial optimization function of the confidentiality capacity, multiple preset communication parameters in the communication system are required, including the distance between each device in the communication system, the radio frequency signal s(n) sent by the multi-antenna signal source, the maximum transmission power P _max of the multi-antenna signal source, the transmission signal beam vector w of the multi-antenna signal source, the gain of each channel, the maximum power P _Tmax of the dual-antenna backscattering tag, the radio frequency signal c(n) sent by the first antenna in the dual-antenna backscattering tag; the radio frequency signal power P _T1 sent by the first antenna in the dual-antenna backscattering tag, the interference signal x(n) sent by the second antenna in the dual-antenna backscattering tag, the interference signal power P _T2 sent by the second antenna in the dual-antenna backscattering tag, and the noise power of the legitimate receiving end. , and the noise power of the illegal eavesdropping end .

Among them, each channel gain includes: the channel gain h _ST1 between the signal source and the first antenna of the backscatter tag; the channel gain h _ST2 between the signal source and the second antenna of the backscatter tag; the channel gain h _SR between the signal source and the receiving end; the channel gain h _SE between the signal source and the eavesdropping end; the channel gain h _TR1 between the first antenna of the backscatter tag and the receiving end; the channel gain h _TR2 between the second antenna of the backscatter tag and the receiving end; the channel gain h _TE1 between the first antenna of the backscatter tag and the eavesdropping end; the channel gain h _TE2 between the second antenna of the backscatter tag and the eavesdropping end.

It should be noted that h represents a gain vector. Since the signal source is a multi-antenna signal source, the gain between the signal source and other devices includes the gain between multiple antennas and other devices. h represents a gain value, that is, the gain between one antenna and other devices.

In addition, each channel gain can be determined by the distance between each device in the communication system. Exemplarily, the fading channels involved in the communication system can all be independent and identically distributed Rayleigh fading channels, and the path loss pl of the channel gain of all the direct channels involved can be calculated by formula (1).

(1)

Where k is a constant coefficient that depends on the antenna characteristics and the average channel loss, d0 is the reference distance of the antenna far field, d is the distance between the two devices, and α is the path loss exponent.

When the path loss pl of the channel gain of the channel between the two devices is determined, the channel gain h of the channel between the two devices can be obtained based on the path loss pl by simulating the Rayleigh fading channel between the two devices.

In addition, it should be noted that the transmission power of the multi-antenna signal source is variable, ranging from 0 to P _max , where P _max can be determined according to actual needs; the power of the dual-antenna backscatter tag is also variable, the power of the first antenna is P _T1 , and the power of the second antenna is P _T2 , satisfying P _T1 +P _T2 ∈ (0 to P _Tmax ), where P _Tmax can also be determined according to actual needs; the environmental noise of the single-antenna receiving end is: ,in is the noise power of the legal receiving end; the environmental noise of the single-antenna illegal eavesdropping end is: ,in is the noise power of the illegal eavesdropping end.

For this communication system, the RF signal c(n) can be demodulated at both the legal receiving end and the illegal eavesdropping end; the interference signal x(n) can be demodulated at the legal receiving end but cannot be demodulated at the illegal eavesdropping end; the RF signal s(n) sent by the signal source can be demodulated at both the legal receiving end and the illegal eavesdropping end.

The system optimized parameters include: the transmit signal beam vector w of the multi-antenna signal source, the transmit power P _T1 of the first antenna in the dual-antenna backscatter tag, and the transmit power P _T2 of the second antenna.

Referring to FIG6 , the confidentiality capacity optimization of the communication system may include the following steps:

Step S1, determining the expression of the confidentiality capacity Cs of the communication system according to the predetermined parameters given by the communication system.

The received signal expression of the legal receiving end is:

(2)

Where z _R (n) represents the noise signal at the legitimate receiving end.

Normalize the power of the RF signal s(n) sent by the signal source, that is, ,make , normalize the power of the RF signal c(n) sent by the first antenna, that is, , normalize the power of the interference signal x(n) sent by the second antenna, that is, , and because , so the signal-to-interference-noise ratio of the legal receiving end can be expressed as:

(3)

The received signal expression of the illegal eavesdropping end is:

(4)

Where z _E (n) represents the noise signal of the illegal eavesdropping end. , then the signal-to-interference-to-noise ratio of the illegal eavesdropping end can be expressed as:

(5)

According to Shannon's theorem, the confidentiality capacity _CS of the communication system is:

(6)

Step S2, since the expression of the confidentiality capacity Cs is in logarithmic (log) form, the real number expression of the logarithm, that is, the log internal expression, is the same as the monotonicity of the Cs expression, so the target optimization function can be determined based on the log internal expression.

Among them, the true number expression in the logarithmic function of the confidentiality capacity Cs is:

(7)

For example, the above formula (7) can be processed by using the fractional programming method, and:

(8)

Based on formula (8), the intermediate optimization function can be constructed :

(9)

The last line in the above formula (9) is a constant and a linear term, which does not need to be processed; the second and third lines in the above formula (9) are, under the condition of high signal-to-noise ratio, and The noise power in the term is small, and The value of is greater than 1 (that is, the confidentiality capacity Cs>1), so both of these two items are negative values, so these two items are concave functions.

Since the intermediate optimization function Middle division The convexity of is uncertain, so the fraction can be converted to convex; for example, the successive convex approximation (SCA) algorithm can be used to continuously convexly approximate the fraction, where the SCA algorithm is an algorithm for solving non-convex optimization problems. Its basic idea is to transform a non-convex problem into a sequence of multiple convex sub-problems, and to approximate the optimal solution of the original problem by continuously solving convex sub-problems. The main advantage of the SCA algorithm is its high efficiency and accuracy, and it can solve complex non-convex optimization problems in a relatively short time.

Using the SCA algorithm, the above uncertain concavity fraction is subjected to first-order Taylor expansion, and the deformed fraction is obtained as follows:

(10)

Where _wt represents the updated solution in each optimization solution.

After the above-mentioned concave-convex conversion process, combined with formulas (9) and (10), the target optimization function can be obtained: for:

(11)

At this time, the target optimization function is in the form of a concave function, and the CVX tool (CVX toolbox is a modeling and solving toolbox for convex optimization in MATLAB) can be used to optimize and solve it;

The optimization problem is organized as:

Among them, the optimization constraints are: , .

Step S3, initialize the beam vector w, initialize the first antenna power P _T1 and the second antenna power P _T1 of the backscatter tag, obtain the initial confidentiality capacity Cs, and at the same time, initialize the target optimization function based on the communication parameters of the communication system , and set the number of iterations k=0, and set the conditional threshold ɛ >0.

Step S4: Solve and update the target optimization function according to initialization or iteration.

Step S5: Optimize the target function under the constraints Solve for the maximum value and obtain the corresponding new solution w _t .

Step S6: Optimize the target function under the constraints Solve for the maximum value and obtain new solutions P _T1 and P _T2 .

Step S7: Calculate the new confidentiality capacity based on the new solution w _t , _PT1 , _PT2 .

Step S8: Determine whether the condition is met at this time If satisfied, it will exit the loop and return the confidentiality capacity , otherwise proceed to S9.

It should be noted that, in each iterative judgment, the _CS in the judgment condition is the confidentiality capacity calculated in the previous iterative calculation.

Step S9: Set the new confidential capacity Assign it to C _S , assign w _t to w, update _PT1 and _PT2 , set k=k+1, and jump to step S4.

After looping the results, the confidentiality capacity of the last iterative calculation can be obtained, which is the maximum confidentiality capacity of the communication system; w _t , _PT1 , and _PT2 obtained by the last iterative calculation are the signal beam vector of the signal source corresponding to the maximum confidentiality capacity, as well as the transmission power of the first antenna and the transmission power of the second antenna of the backscattering tag.

Exemplarily, the above communication system is built in a simulation environment. A four-antenna signal source, a dual-antenna backscatter tag, where the first antenna sends a radio frequency signal and the second antenna sends an interference signal, a single-antenna legal receiving end, and a single-antenna illegal eavesdropping end can be set. Assume that the signal source is 100m away from the backscatter tag, 105m away from the legal receiving end and the illegal eavesdropping end, and 5m away from the legal receiving end and the illegal eavesdropping end. The power of the signal source and the power of the backscatter tag are determined according to actual needs.

During the simulation, the beam vector of the signal source is randomly initialized, and the power of the RF signal sent in the backscatter tag and the power of the interference signal are evenly distributed at the beginning to obtain the initial confidentiality capacity value. Through the optimization flowchart shown in Figure 6 above, MATLAB simulation is performed to obtain the simulation results of Figure 7. The simulation compares the unoptimized (baseline algorithm), only optimized tag power allocation, only optimized beam vector w, and simultaneously optimized tag power allocation and beam vector w. Referring to Figure 7, it can be seen that the value of the communication system's initial confidentiality capacity is 0.23. After optimization, the new confidentiality capacity value can be obtained to be 2.00, and the transmission performance of the communication system is improved by about 9.4dB. At the same time, it can be seen from the simulation results that compared with optimizing the power allocation of the tag, the optimization of the signal source beam vector w plays a major role in improving the performance of the communication system. This shows that this system has certain engineering value.

The contribution of the communication method proposed in the present application is that, for a multi-antenna backscatter communication system, in the presence of an eavesdropper, on the one hand, by artificially sending an interference signal at the backscatter tag end, the signal-to-noise ratio of the radio frequency signal received by the illegal eavesdropper is reduced, thereby achieving confidential communication, that is, realizing a more secure communication system and improving the anti-eavesdropping performance of the communication system; on the other hand, by optimizing the signal beam vector of the signal source sending the signal, and optimizing the power allocation of the backscatter tag, according to the constraint conditions, the confidentiality capacity of the communication system is maximized, thereby improving the transmission performance of the communication system; in addition, for the optimization of the confidentiality capacity of the communication system, the SCA idea and the fractional programming idea are innovatively applied to the solution of the optimization problem of the confidentiality capacity, so as to achieve the optimal confidentiality capacity of the communication system under certain conditions, which can simplify the optimization complexity of the confidentiality capacity and improve the optimization efficiency of the confidentiality capacity.

It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

Based on the same inventive concept, the embodiment of the present application also provides a communication device for implementing the communication method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more communication device embodiments provided below can refer to the limitations on the communication method above, and will not be repeated here.

In an exemplary embodiment, as shown in FIG8 , a communication device is provided, including: an adjustment module 801, wherein:

The adjustment module 801 is used to adjust the configuration parameters of the target device so that the target device transmits signals based on the adjusted configuration parameters; wherein the target device includes a signal source and/or a backscatter tag, and the configuration parameters include a signal beam vector of the signal source and/or the power of the backscatter tag.

In one of the embodiments, the adjustment module 801 is used to construct a target optimization function based on an initial optimization function corresponding to the confidentiality capacity of the communication system; determine the target configuration parameters by solving the target optimization function based on the maximum principle; and adjust the configuration parameters of the target device according to the target configuration parameters.

In one embodiment, the adjustment module 801 is used to extract the real number expression of the logarithmic function from the initial optimization function corresponding to the confidentiality capacity of the communication system to obtain the target real number expression; and construct the target optimization function based on the target real number expression.

In one embodiment, the adjustment module 801 is used to perform concave-convex conversion on the fraction with uncertain concave-convexity in the target real number expression to obtain the target optimization function.

In one embodiment, the adjustment module 801 is used to convert the target real number expression into an intermediate optimization function; perform concave-convex conversion on the uncertain fraction in the intermediate optimization function to obtain the target optimization function.

In one of the embodiments, the adjustment module 801 is used to obtain the distance value between every two devices in the communication system, the noise power of the receiving end, and the noise power of the eavesdropping end; taking the target optimization function as the maximum principle, the signal beam vector of the signal source and the power of the backscatter tag are used as iterative variables, and the distance value between every two devices in the communication system, the noise power of the receiving end, and the noise power of the eavesdropping end are substituted into the target optimization function for iterative calculation to obtain the target configuration parameters.

Each module in the above communication device can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module.

In an exemplary embodiment, a communication device is provided, the communication device comprising: a memory, a transceiver, and a processor;

A memory is used to store a computer program; a transceiver is used to send and receive data under the control of a processor; and a processor is used to read the computer program in the memory and execute the steps of the communication method in any of the above embodiments.

In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the communication method in any of the above embodiments are implemented.

In one embodiment, a computer program product is provided, including a computer program, which implements the steps of the communication method in any of the above embodiments when executed by a processor.

Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims (15)

1. A communication system, characterized in that the communication system comprises: a signal source, a backscatter tag, a receiving end and an eavesdropping end; wherein: The signal source is used to send a radio frequency signal; The backscatter tag is used to send the radio frequency signal and the interference signal; The receiving end is used to receive a combined signal and identify the radio frequency signal from the combined signal; the combined signal includes the radio frequency signal and the interference signal; The eavesdropping terminal is used to receive the combined signal; Wherein, the backscatter tag is provided with a first antenna and a second antenna; The backscatter tag is used to forward the radio frequency signal through the first antenna and send the interference signal through the second antenna; The system further comprises: a control device; The control device is used to adjust the configuration parameters of the target device so that the target device performs signal transmission based on the adjusted configuration parameters; wherein the target device includes the signal source and the backscatter tag, the configuration parameters include the signal beam vector of the signal source and the power of the backscatter tag, and the power of the backscatter tag includes the transmission power of the first antenna and the transmission power of the second antenna; The step of adjusting the configuration parameters of the target device includes: Based on the initial optimization function corresponding to the confidentiality capacity of the communication system and a plurality of preset communication parameters, a target optimization function is constructed; the plurality of preset communication parameters include the distance value between each two devices, the noise power of the receiving end, and the noise power of the eavesdropping end; the target optimization function is a convex optimization function obtained by converting the concavity and convexity of the initial optimization function; Taking the target optimization function as the maximum principle, determining the target configuration parameters by solving the target optimization function; The configuration parameters of the target device are adjusted according to the target configuration parameters. 2 . The communication system according to claim 1 , wherein the signal source comprises a carrier generator, and a distance between the signal source and the backscatter tag is less than a preset distance threshold. 3. The communication system according to claim 1 is characterized in that the backscatter tag is also used to convert the radio frequency signal into energy for power supply. 4. The communication system according to claim 1 is characterized in that the receiving end is specifically used to receive the radio frequency signal and interference signal sent by the backscatter tag, and receive the radio frequency signal sent by the signal source. 5. The communication system according to claim 1 is characterized in that the eavesdropping end is specifically used to receive the radio frequency signal and interference signal sent by the backscatter tag, and receive the radio frequency signal sent by the signal source. 6. A communication method, characterized in that it is applied to the communication system according to any one of claims 1 to 5, and the method comprises: The signal source sends a radio frequency signal; The backscatter tag sends the radio frequency signal and the interference signal; The receiving end receives a combined signal and identifies the radio frequency signal from the combined signal; the combined signal includes the radio frequency signal and the interference signal; The eavesdropping end receives the combined signal; The backscatter tag is provided with a first antenna and a second antenna, the radio frequency signal is forwarded through the first antenna, and the interference signal is sent through the second antenna; The control device adjusts the configuration parameters of the target device so that the target device performs signal transmission based on the adjusted configuration parameters; wherein the target device includes the signal source and the backscatter tag, the configuration parameters include the signal beam vector of the signal source and the power of the backscatter tag, and the power of the backscatter tag includes the transmission power of the first antenna and the transmission power of the second antenna; The step of adjusting the configuration parameters of the target device includes: Based on the initial optimization function corresponding to the confidentiality capacity of the communication system and a plurality of preset communication parameters, a target optimization function is constructed; the plurality of preset communication parameters include the distance value between each two devices, the noise power of the receiving end, and the noise power of the eavesdropping end; the target optimization function is a convex optimization function obtained by converting the concavity and convexity of the initial optimization function; Taking the target optimization function as the maximum principle, determining the target configuration parameters by solving the target optimization function; The configuration parameters of the target device are adjusted according to the target configuration parameters. 7. A communication method, characterized in that it is applied to the communication system according to any one of claims 1 to 5, and the method comprises: Adjusting configuration parameters of a target device so that the target device performs signal transmission based on the adjusted configuration parameters; The target device includes the signal source and the backscatter tag, the configuration parameters include a signal beam vector of the signal source and a power of the backscatter tag, the backscatter tag is provided with a first antenna and a second antenna, and the power of the backscatter tag includes a transmission power of the first antenna and a transmission power of the second antenna; The adjusting of the configuration parameters of the target device includes: Based on the initial optimization function corresponding to the confidentiality capacity of the communication system and a plurality of preset communication parameters, a target optimization function is constructed; the plurality of preset communication parameters include the distance value between each two devices, the noise power of the receiving end, and the noise power of the eavesdropping end; the target optimization function is a convex optimization function obtained by converting the concavity and convexity of the initial optimization function; Taking the target optimization function as the maximum principle, determining the target configuration parameters by solving the target optimization function; The configuration parameters of the target device are adjusted according to the target configuration parameters. 8. The method according to claim 7, characterized in that the initial optimization function corresponding to the confidentiality capacity of the communication system and a plurality of preset communication parameters are used to construct a target optimization function, comprising: Extracting a real number expression of a logarithmic function from an initial optimization function corresponding to the confidentiality capacity of the communication system to obtain a target real number expression; A target optimization function is constructed based on the target true number expression and a plurality of preset communication parameters. 9. The method according to claim 8, characterized in that the step of constructing a target optimization function based on the target true number expression and a plurality of preset communication parameters comprises: The target optimization function is obtained by performing a concave-convex conversion on the uncertain fraction in the target real number expression and combining it with a plurality of preset communication parameters. 10. The method according to claim 9, characterized in that the step of performing a concave-convex conversion on the uncertain fraction in the target real number expression and combining a plurality of preset communication parameters to obtain the target optimization function comprises: Converting the target true number expression into an intermediate optimization function; The target optimization function is obtained by performing a concave-convex conversion on the uncertain concave-convex fraction in the intermediate optimization function and combining it with a plurality of preset communication parameters. 11. The method according to claim 7, characterized in that the determining of target configuration parameters by solving the target optimization function based on the maximum principle comprises: Obtaining the distance value between every two devices in the communication system, the noise power of the receiving end, and the noise power of the eavesdropping end; Taking the target optimization function as the maximum principle, the signal beam vector of the signal source and the power of the backscatter tag as iterative variables, the distance value between every two devices in the communication system, the noise power of the receiving end and the noise power of the eavesdropping end are substituted into the target optimization function for iterative calculation to obtain the target configuration parameters. 12. A communication device, characterized in that it is applied to the communication system according to any one of claims 1 to 5, and the device comprises: An adjustment module, used to adjust the configuration parameters of the target device so that the target device performs signal transmission based on the adjusted configuration parameters; The target device includes the signal source and the backscatter tag, the configuration parameters include a signal beam vector of the signal source and a power of the backscatter tag, the backscatter tag is provided with a first antenna and a second antenna, and the power of the backscatter tag includes a transmission power of the first antenna and a transmission power of the second antenna; The adjustment module is used to construct a target optimization function based on an initial optimization function corresponding to the confidentiality capacity of the communication system and multiple preset communication parameters; taking the target optimization function as the maximum principle, determining the target configuration parameters by solving the target optimization function; adjusting the configuration parameters of the target device according to the target configuration parameters; the multiple preset communication parameters include the distance value between every two devices, the noise power of the receiving end, and the noise power of the eavesdropping end; the target optimization function is a convex optimization function obtained by converting the convexity of the initial optimization function. 13. A communication device, characterized in that the communication device comprises: a memory, a transceiver, and a processor: The memory is used to store a computer program; the transceiver is used to send and receive data under the control of the processor; and the processor is used to read the computer program in the memory and execute the method as described in any one of claims 7 to 11. 14. A computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of the method according to any one of claims 7 to 11 are implemented. 15. A computer program product, comprising a computer program, characterized in that when the computer program is executed by a processor, the steps of the method according to any one of claims 7 to 11 are implemented.