CN-122027070-A - Self-adaptive covert communication method based on channel state information

CN122027070ACN 122027070 ACN122027070 ACN 122027070ACN-122027070-A

Abstract

The application provides a self-adaptive hidden communication method based on channel state information, which comprises the following steps of constructing a hidden communication system consisting of a transmitter, a receiver and an eavesdropper, wherein the receiver is provided with double antennas and can be switched between a half-duplex mode and a full-duplex mode, the receiver acquires the channel state information between itself and the eavesdropper and adaptively switches a working mode according to the channel state information, the information transmitting power of the transmitter and the artificial noise transmitting power of the receiver are jointly optimized, the minimum hidden rate of the system in the half-duplex mode and the full-duplex mode is maximized on the premise that the hidden constraint, the power upper limit constraint and the communication interrupt constraint are met, the method is more suitable for an actual scene, the nonlinear coupling optimization problem is decoupled into a problem that the nonlinear coupling optimization problem can be quickly solved through gradient descent or numerical optimization, the optimal solution can be converged only through iterative updating of power parameters without complex traversal calculation, and the real-time performance is remarkably improved.

Inventors

LIU XIZE
LIU SHUQIN
Zhan Daijie
LI JIAHUAN
ZHAN JIAHUI
CHEN RUI
LIU XIAOJUN

Assignees

三峡大学

Dates

Publication Date: 20260512
Application Date: 20260131

Claims (10)

1. The self-adaptive covert communication method based on the channel state information is characterized by comprising the following steps of: The method comprises the steps of constructing a hidden communication system consisting of a transmitter, a receiver and an eavesdropper, wherein the receiver is provided with double antennas and can be switched between a half duplex mode and a full duplex mode, the receiver acquires channel state information between itself and the eavesdropper, the channel state information is estimated through a pilot signal and is adaptively switched to a working mode according to the channel state information, the information transmitting power of the transmitter and the artificial noise transmitting power of the receiver in the full duplex mode are jointly optimized, and the minimum hidden rate of the system in the half duplex mode and the full duplex mode is maximized on the premise that the hidden constraint, the power upper limit constraint and the communication interruption constraint are met.
2. The adaptive covert communication method based on channel state information according to claim 1, wherein the adaptive mode switching rule of the receiver is that the receiver compares the square of the channel gain amplitude of the receiver and an eavesdropper with a preset threshold value, when the square of the channel gain amplitude is smaller than or equal to the preset threshold value, the receiver works in a half duplex mode and only receives information transmitted by the transmitter, and when the square of the channel gain amplitude is larger than the preset threshold value, the receiver switches to a full duplex mode and transmits artificial noise to interfere detection of the eavesdropper while receiving the information.
3. The adaptive covert communication method according to claim 1, wherein the receiver estimates channel state information of itself and an eavesdropper by means of a pilot signal, the channel state information including channel gain parameters between the receiver and the eavesdropper.
4. The method of claim 1 wherein the concealment constraint is defined as whether an average minimum detection error probability of an eavesdropper on information transmitted by a transmitter is not lower than a preset concealment threshold, the average minimum detection error probability is a weighted sum of false alarm probability and missed detection probability of the eavesdropper, and a statistical average result of channel randomness is considered.
5. The method for adaptive covert communication based on channel state information of claim 1, wherein the communication interruption constraint is defined as a probability that a communication interruption probability in a half duplex mode and a communication interruption probability in a full duplex mode do not exceed a preset interruption threshold, the interruption probability is a probability that a signal to noise ratio received by a receiver is lower than the preset interruption threshold, and reliability of information transmission is impaired.
6. The adaptive covert communication method based on channel state information of claim 1, wherein in the process of jointly optimizing the transmitting power, a Leibniz rule is adopted to exchange a calculus and an integration sequence, so that a nonlinear coupling optimization problem between the transmitting power of the transmitter information and the transmitting power of the artificial noise of the receiver is decoupled and converted into a form capable of being solved iteratively.
7. The adaptive covert communication method based on channel state information according to claim 1, wherein the joint optimization is realized by a gradient descent or numerical optimization algorithm, and the optimization process comprises the steps of initializing the transmitting power of transmitter information, the transmitting power of artificial noise of a receiver and the transmission probability, determining the mode selection probability of the receiver based on the channel state information, calculating the detection error probability of an eavesdropper and the interruption probability of a system, checking whether the corresponding constraint is met, calculating the gradient of the minimum covert rate on each power parameter, updating the parameters through iteration, and ensuring that the updated power parameters do not exceed the respective maximum power upper limit through a projection operator until the convergence condition is met or the maximum iteration times are reached.
8. The adaptive covert communication method based on channel state information according to claim 1, wherein the communication system adopts a quasi-static Rayleigh fading channel model, the channel fading coefficients of all links in a single time slot are kept unchanged, the channel fading coefficients of different time slots are changed independently, the square of the channel gain of each link obeys the exponential distribution of which the parameter is the reciprocal of the mean value, and the local noise of each node is additive Gaussian white noise with zero mean value and fixed variance.
9. The adaptive blind communication method according to claim 1, wherein the probability of the receiver switching to the half duplex mode and the full duplex mode is calculated based on the rayleigh fading distribution characteristic to which the channel gain is subjected, reflecting the selection probabilities of the two modes under different channel conditions.
10. The adaptive covert communication method based on channel state information according to claim 7, wherein in the parameter iterative updating process, the updated transmitter information transmitting power and receiver artificial noise transmitting power are ensured not to exceed respective maximum power upper limits by a projection operator, and the updating step length is controlled by a preset learning rate, so that the algorithm is ensured to converge to an optimal solution.

Description

Self-adaptive covert communication method based on channel state information Technical Field The invention belongs to the technical field of covert communication, and particularly relates to a self-adaptive covert communication method based on channel state information. Background In the prior art of covert communication, although Half-Duplex (HD) mode can ensure transmission efficiency, but lacks an interference mechanism to an eavesdropper, the concealment is insufficient, and Full-Duplex (FD) mode can improve the concealment through artificial noise, but can introduce self-interference, and a fixed working mode cannot adapt to dynamic change of a channel. In addition, the prior art often ignores the transient nature of the Channel State Information (CSI), and does not implement adaptive switching of the operating mode, resulting in a system that has difficulty in achieving an optimal balance between concealment and reliability. Meanwhile, the power optimization of the transmitting end and the receiving end has the coupling problem, the solving efficiency is low, the channel fluctuation cannot be quickly adapted, and the transmission interruption or hidden failure is easy to occur. Therefore, how to use CSI to realize adaptive switching of working modes and efficiently solve the problem of power coupling optimization becomes a key for improving the performance of covert communication. Based on this background, mode switching has received a great deal of attention. At present, some inventions have been studied for mode switching in covert communication. In the prior art, on one hand, the artificial noise power is not optimized, the D2D switching is coordinated by the base station, the signaling overhead is high, and on the other hand, error compensation is not considered, the calculation of the traversal capacity is complex, and the response is slow. Therefore, it is desirable to provide an adaptive covert communication method based on CSI driving, which adjusts the operation mode in real time and is suitable for the actual scenario. Disclosure of Invention The invention aims to solve the technical problems in the background and provides a self-adaptive hidden communication method based on channel state information, which comprises the following steps: The method comprises the steps of constructing a hidden communication system consisting of a transmitter, a receiver and an eavesdropper, wherein the receiver is provided with double antennas and can be switched between a half duplex mode and a full duplex mode, the receiver acquires channel state information between itself and the eavesdropper, the channel state information is estimated through a pilot signal and is adaptively switched to a working mode according to the channel state information, the information transmitting power of the transmitter and the artificial noise transmitting power of the receiver in the full duplex mode are jointly optimized, and the minimum hidden rate of the system in the half duplex mode and the full duplex mode is maximized on the premise that the hidden constraint, the power upper limit constraint and the communication interruption constraint are met. In the preferred scheme, the adaptive mode switching rule of the receiver is that the receiver compares the square of the channel gain amplitude of the receiver and an eavesdropper with a preset threshold value, when the square of the channel gain amplitude is smaller than or equal to the preset threshold value, the receiver works in a half duplex mode and only receives information transmitted by the transmitter, and when the square of the channel gain amplitude is larger than the preset threshold value, the receiver switches to a full duplex mode and transmits artificial noise to interfere detection of the eavesdropper while receiving the information. In a preferred embodiment, the receiver estimates its channel state information with the eavesdropper via the pilot signal, the channel state information including channel gain parameters between the receiver and the eavesdropper. In a preferred scheme, the concealment constraint is defined as that the average minimum detection error probability of an eavesdropper on whether the transmitter transmits information is not lower than a preset concealment threshold value, the average minimum detection error probability is the weighted sum of the false alarm probability and the missed detection probability of the eavesdropper, and the statistical average result of the randomness of the channel is considered. In the preferred scheme, the communication interruption constraint is defined as that the communication interruption probability in the half duplex mode and the full duplex mode does not exceed a preset interruption threshold, wherein the interruption probability is the probability that the signal to noise ratio received by a receiver is lower than the signal to noise ratio of the preset interruption threshold, and the reliability