A smart reflector-assisted communication anti-interference method based on receiving feedback

Abstract

The present invention discloses a method for communication anti-interference assisted by an intelligent reflective surface based on receiving feedback. First, an anti-interference communication system model assisted by an intelligent reflective surface is constructed, and the reflection coefficient of the intelligent reflective surface is initialized. The sending node and the interference node send communication signals and interference signals respectively, and the receiving node measures the received signal-to-interference-noise ratio. Then, the intelligent reflective surface adjusts the reflection coefficient of each reflection unit one by one according to the feedback of the receiving node, and finally repeats until its state converges. The intelligent reflective surface performs reflection beamforming to assist in anti-interference according to the determined reflection coefficients of each reflection unit. The intelligent reflective surface of the present invention dynamically adjusts the reflection coefficient through binary search according to the change of the received signal-to-interference-noise ratio of the receiver, and never depends on the channel state information of the interference node. It can still achieve an anti-interference effect that is almost the same as the performance upper bound under the condition of known interference node channel state information, which greatly expands the application potential of the intelligent reflective surface in actual communication anti-interference scenarios.

Description

Technical Field

[0001] The invention belongs to the field of intelligent reflective surface-assisted wireless communication anti-interference, and in particular relates to an intelligent reflective surface-assisted communication anti-interference method based on receiving feedback. Background Art

[0002] Due to the openness of the wireless transmission environment, wireless communications face unavoidable interference problems, and the reliability of information transmission is restricted. Especially in areas such as national security, disaster warning, and public security monitoring, wireless interference can cause information transmission interruptions, which will cause major security threats and economic losses. In the face of malicious wireless interference, traditional schemes such as hopping expansion and direct expansion can be used to improve the anti-interference ability of communications. However, simply increasing the hopping speed, the number of hopping points, and the sequence length has limited potential and it is difficult to achieve a fundamental breakthrough. On the other hand, when faced with wide-band and high-power interference from jammers, such schemes are difficult to work. Therefore, how to seek new anti-interference paths to break through existing technical bottlenecks, thereby providing a solid guarantee for improving the anti-interference ability of key wireless communication nodes, is an important issue that needs to be solved in current wireless communications.

[0003] Recently, smart reflective surface technology has received keen attention from the wireless communication academic and industrial communities, and is considered to be one of the key enabling technologies for the future 6G. Through its unique channel control capability, the smart reflective surface can dynamically reconstruct the wireless propagation environment, so that the wireless signal can be enhanced or weakened at the receiving point as needed, thereby achieving the goals of blind area coverage enhancement, hot spot area capacity improvement, and interference suppression. In essence, the smart reflective surface is a two-dimensional electromagnetic metamaterial that can flexibly control its reflection coefficient by dynamically adjusting the equivalent impedance of each reflective unit, thereby achieving phase control of the reflected signal through it and achieving a smart reflection effect. Based on the above characteristics, the smart reflective surface provides a new idea for wireless communication anti-interference, that is, it can artificially construct a reflection propagation path for the interference signal, so that it can cancel out the interference signal of the direct propagation path, and achieve "treating the person with his own knowledge". Compared with traditional anti-interference solutions, the anti-interference method based on reflection cancellation of intelligent reflecting surface can effectively deal with high-power and wide-band interference, because its principle is not to avoid or disperse interference, but to use the interference itself to cancel the interference. Therefore, it can effectively enhance the ability of key nodes to deal with strong interference and provide more reliable technical support for ensuring communication security.

[0004] At present, there are related literatures that study the anti-jamming communication method assisted by intelligent reflectors, and explore the core issue of the design of intelligent reflector reflection beamforming. The literature [Y.Sun et al., "Robust Design for RIS-Assisted Anti-Jamming Communications With Imperfect Angular Information: A Game-Theoretic Perspective," in IEEE Transactions on Vehicular Technology, vol. 71, no. 7, pp. 7967-7972, July 2022] uses Bayesian Stackelberg game to model the behavior of the transmitter and the jammer, modeling the transmitter as a leader and the jammer as a follower. Under this model, the reflection beamforming of the intelligent reflector is optimized, which improves the anti-jamming reception capability of the system. The literature [Y.Sun et al., "RIS-Assisted Robust Hybrid Beamforming Against Simultaneous Jamming and Eavesdropping Attacks," in IEEE Transactions on Wireless Communications, vol.21, no.11, pp.9212-9231, Nov.2022] studied the use of smart reflector wireless channel control capabilities under imperfect channel state information to achieve anti-interference and anti-eavesdropping reception, and designed a heuristic smart reflector reflection beamforming scheme under the constraints of minimum achievable rate and maximum transmit power. The literature [S.Hu, X.Yuan, W.Ni, X.Wangand A.Jamalipour,"RIS-Assisted Jamming Rejection and Path Planning for UAV-Borne IoT Platform:A New Deep Reinforcement Learning Framework,"in IEEE Internet of Things Journal, vol.10, no.22, pp.20162-20173, Nov.15, 2023] uses a deep deterministic gradient strategy to jointly optimize the UAV flight trajectory and the reflection beamforming of the intelligent reflector based on the change of the UAV receiving data rate to enhance the anti-interference capability of the UAV uplink communication.

[0005] It should be noted that in all the above documents, it is assumed that the legitimate communication party (transmitter / intelligent reflector / receiver) can fully or partially obtain the channel state information between the jammer and the intelligent reflector and between the jammer and the receiver, so as to optimize the reflection coefficient of the intelligent reflector. However, in actual systems, the jammer and the legitimate communication party are in an adversarial and non-cooperative relationship, and it is difficult for the latter to obtain the channel state information of the former through methods such as channel estimation. For this reason, the application scenarios of the above results based on the known jammer channel state information are limited, and it is difficult to meet the communication anti-interference requirements in actual applications where the jammer channel state information is unknown. Summary of the invention

[0006] In view of the above problems, the purpose of the present invention is to provide a smart reflective surface assisted communication anti-interference method based on receiving feedback, so that the smart reflective surface can obtain an optimized smart reflective surface reflection coefficient through search without relying on the channel state information of the interfering node.

[0007] The specific technical solution for achieving the purpose of the present invention is:

[0008] A method for anti-interference of intelligent reflective surface-assisted communication based on receiving feedback comprises the following steps:

[0009] Step 1: construct an anti-interference communication system model based on the assistance of the intelligent reflective surface, and initialize the reflection coefficient of the intelligent reflective surface;

[0010] Step 2: The sending node and the interference node send the communication signal and the interference signal respectively, and the receiving node measures the received signal-to-interference-noise ratio, which is recorded as

[0011] Step 3: The intelligent reflective surface adjusts the reflection coefficient of each reflective unit one by one according to the feedback from the receiving node;

[0012] Step 4: Repeat step 3 until the state converges, and the intelligent reflection surface performs reflection beamforming to assist in anti-interference according to the determined reflection coefficients of each reflection unit.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The solution of the present invention proposes an intelligent reflector-assisted communication anti-interference method based on receiving feedback that does not require jammer channel state information. The intelligent reflector in the solution dynamically adjusts the reflection coefficient through binary search according to the change of the received signal-to-interference-noise ratio of the receiver, thereby realizing transmit beamforming optimization without relying on the jammer channel state information. This optimization strategy can be widely used in wireless communication scenarios assisted by intelligent reflectors, and is not limited to the communication anti-interference scenarios listed above, and has broad reference prospects.

[0015] The present invention is further described below in conjunction with specific implementation modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flowchart of the intelligent reflector-assisted communication anti-interference method based on receiving feedback.

[0017] Figure 2 It is a schematic diagram of a model of an anti-interference communication system assisted by a smart reflective surface in an embodiment of the present invention.

[0018] Figure 3 This is a flow chart of searching the reflection coefficient phase of the nth reflection unit of the intelligent reflection surface based on the binary search method of the present invention.

[0019] Figure 4 The figure is a schematic diagram showing how the signal-to-interference-and-noise ratio of a receiver varies with the transmission power of a jammer when the number of smart reflective surface units is N=80 in an embodiment of the present invention.

[0020] Figure 5 The figure is a schematic diagram showing how the signal to interference and noise ratio of a receiver varies with the transmission power of a jammer when the number of smart reflective surface units is N=100 in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] A method for anti-interference of intelligent reflective surface-assisted communication based on receiving feedback comprises the following steps:

[0022] Step 1: Construct an anti-interference communication system model based on the assistance of the intelligent reflective surface and initialize the reflection coefficient of the intelligent reflective surface:

[0023] The system at least includes a sending node S, a receiving node D, an interference node J and an intelligent reflective surface R. When the sending node S sends a communication signal to the receiving node D, the interference node J sends an interference signal to the receiving node S to destroy its receiving effect;

[0024] The intelligent reflective surface R achieves an anti-interference reception effect by offsetting the interference signal reflected and the interference signal transmitted directly;

[0025] The reflection coefficient of the initialized smart reflection surface is specifically:

[0026] Assume that the sending node S, receiving node D, and interference node J are all equipped with a single antenna, and the intelligent reflection surface R is equipped with N reflection units. The reflection coefficient amplitude of each reflection unit is set to its maximum value 1, and the phase is in the interval [0,2π). When initializing, the reflection coefficient phase of each reflection unit is set to n=1,...,N.

[0027] Step 2: The sending node and the interference node send the communication signal and the interference signal respectively, and the receiving node measures the received signal-to-interference-noise ratio, which is recorded as

[0028] Step 3: The intelligent reflective surface adjusts the reflection coefficient of each reflective unit one by one according to the feedback from the receiving node:

[0029] Step 3-1: According to the reflection coefficient of the smart reflective surface R initialized in step 1, let n = 1,

[0030] Step 3-2: Determine the reflection coefficient phase θ of the nth reflection unit of the optimal smart reflection surface R based on the dichotomy method n :

[0031] Step 3-2-1, the intelligent reflective surface R will n Set to At this time, the receiving node D measures the received signal-to-interference-noise ratio and records it as

[0032] Step 3-2-2: Smart reflective surface R will θ n Set to At this time, the receiving node D measures the received signal-to-interference-noise ratio and records it as

[0033] Step 3-2-3: Receiving node D compares and Determine the information fed back to the intelligent reflective surface R. The specific process is as follows:

[0034] like The receiving node D feeds back the bit information "000" to the smart reflective surface R; if The receiving node D feeds back the bit information "001" to the smart reflective surface R; if The receiving node D feeds back the bit information "010" to the smart reflective surface R; if The receiving node D feeds back the bit information "011" to the smart reflective surface R; if The receiving node D feeds back the bit information "100" to the smart reflective surface R; if The receiving node D then feeds back bit information "101" to the smart reflective surface R;

[0035] Step 3-2-4: The intelligent reflector R determines θ based on the feedback information from the receiving node D. n Search interval The specific process is:

[0036] If the smart reflective surface R receives "000" or "001", then If the smart reflective surface R receives "010" or "011", then If the smart reflective surface R receives "100" or "101", then Then, compare and like Then

[0037] Step 3-2-5: The intelligent reflective surface R searches and adjusts θ in the search interval n , the specific process is:

[0038] like Then the reflection coefficient phase of the nth reflection unit is adjusted to At this time, the receiving node D records the measured received signal-to-interference-noise ratio as like Then the reflection coefficient phase of the nth reflection unit is adjusted to At this time, the receiving node D records the measured received signal-to-interference-noise ratio as

[0039] Step 3-2-6: Receiving node D calculates and The absolute value of the difference between

[0040] Step 3-2-7: If Δγ n If the value is less than the set threshold ξ, repeat steps 3-2-5 and 3-2-6; otherwise, the receiving node D will Recorded as And feedback the bit information "110" to the smart reflector R. After receiving this information, the reflection coefficient phase of the nth reflector unit is adjusted to

[0041] Step 3-3, let n=n+1;

[0042] Step 3-4: Repeat steps 3-2 and 3-3 until n=N.

[0043] Step 4: Repeat step 3 until the state converges, that is, the receiving node D calculates and The absolute value of the difference between If it is less than the set threshold σ, then terminate; otherwise, let And repeat step 3, the intelligent reflective surface performs reflection beamforming to assist in anti-interference according to the determined reflection coefficients of each reflective unit.

[0044] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the following steps are implemented:

[0045] Step 1: construct an anti-interference communication system model based on the assistance of the intelligent reflective surface, and initialize the reflection coefficient of the intelligent reflective surface;

[0046] Step 2: The sending node and the interference node send the communication signal and the interference signal respectively, and the receiving node measures the received signal-to-interference-noise ratio, which is recorded as

[0047] Step 3: The intelligent reflective surface adjusts the reflection coefficient of each reflective unit one by one according to the feedback from the receiving node;

[0048] Step 4: Repeat step 3 until the state converges, and the intelligent reflection surface performs reflection beamforming to assist in anti-interference according to the determined reflection coefficients of each reflection unit.

[0049] Example

[0050] Combination Figure 1 , a smart reflective surface assisted communication anti-interference method based on receiving feedback, comprising the following steps:

[0051] Step 1: Construct an anti-interference communication system model based on the assistance of the intelligent reflective surface and initialize the reflection coefficient of the intelligent reflective surface:

[0052] Combination Figure 2 , the system at least includes a sending node S, a receiving node D, an interference node J and an intelligent reflective surface R, and while the sending node S sends a communication signal to the receiving node D, the interference node J sends an interference signal to the receiving node S to destroy its receiving effect;

[0053] The intelligent reflective surface R achieves an anti-interference reception effect by offsetting the interference signal reflected and the interference signal transmitted directly;

[0054] The reflection coefficient of the initialized smart reflection surface is specifically:

[0055] Assume that the sending node S, receiving node D, and interference node J are all equipped with a single antenna, and the intelligent reflection surface R is equipped with N reflection units. The reflection coefficient amplitude of each reflection unit is set to its maximum value 1, and the phase is in the interval [0,2π). When initializing, the reflection coefficient phase of each reflection unit is set to n=1,...,N.

[0056] Step 2: The sending node and the interference node send the communication signal and the interference signal respectively, and the receiving node measures the received signal-to-interference-noise ratio, which is recorded as

[0057] Step 3: The intelligent reflective surface adjusts the reflection coefficient of each reflective unit one by one according to the feedback from the receiving node:

[0058] Step 3-1: According to the reflection coefficient of the smart reflective surface R initialized in step 1, let n = 1,

[0059] Step 3-2: Combination Figure 3 , based on the dichotomy method, the reflection coefficient phase θ of the nth reflection unit of the optimal smart reflection surface R is determined n :

[0060] Step 3-2-1, the intelligent reflective surface R will n Set to At this time, the receiving node D measures the received signal-to-interference-noise ratio and records it as

[0061] Step 3-2-2: Smart reflective surface R will θ n Set to At this time, the receiving node D measures the received signal-to-interference-noise ratio and records it as

[0062] Step 3-2-3: Receiving node D compares and Determine the information fed back to the intelligent reflective surface R. The specific process is as follows:

[0063] like The receiving node D feeds back the bit information "000" to the smart reflective surface R; if The receiving node D feeds back the bit information "001" to the smart reflective surface R; if The receiving node D feeds back the bit information "010" to the smart reflective surface R; if The receiving node D feeds back the bit information "011" to the smart reflective surface R; if The receiving node D feeds back the bit information "100" to the smart reflective surface R; if The receiving node D then feeds back bit information "101" to the smart reflective surface R;

[0064] Step 3-2-4: The intelligent reflector R determines θ based on the feedback information from the receiving node D. n Search interval The specific process is:

[0065] If the smart reflective surface R receives "000" or "001", then If the smart reflective surface R receives "010" or "011", then If the smart reflective surface R receives "100" or "101", then Then, compare and like Then

[0066] Step 3-2-5: The intelligent reflective surface R searches and adjusts θ in the search interval n , the specific process is:

[0067] like Then the reflection coefficient phase of the nth reflection unit is adjusted to At this time, the receiving node D records the measured received signal-to-interference-noise ratio as like Then the reflection coefficient phase of the nth reflection unit is adjusted to At this time, the receiving node D records the measured received signal-to-interference-noise ratio as

[0068] Step 3-2-6: Receiving node D calculates and The absolute value of the difference between

[0069] Step 3-2-7: If Δγ n If the value is less than the set threshold ξ, repeat steps 3-2-5 and 3-2-6; otherwise, the receiving node D will Recorded as And feedback the bit information "110" to the smart reflector R. After receiving this information, the reflection coefficient phase of the nth reflector unit is adjusted to

[0070] Step 3-3, let n=n+1;

[0071] Step 3-4: Repeat steps 3-2 and 3-3 until n=N.

[0072] Step 4: Repeat step 3 until the state converges, that is, the receiving node D calculates and The absolute value of the difference between If it is less than the set threshold σ, then terminate; otherwise, let And repeat step 3, the intelligent reflective surface performs reflection beamforming to assist in anti-interference according to the determined reflection coefficients of each reflective unit.

[0073] according to Figure 1The implementation process of the present invention is further explained by taking the intelligent reflector R with N reflective units as an example (considering the two cases of N = 80 and N = 100). The other simulation parameters are set as follows: carrier frequency 750MHz, carrier wavelength 0.4m, intelligent reflector R unit spacing 0.15m, receiving node D Gaussian white noise power The three-dimensional coordinates of the transmitting node S, receiving node D and interference node J are (500, 2, 5), (0, 2, 10) and (-500, 2, 5) respectively. The smart reflective surface R is deployed on the yoz plane, and the three-dimensional coordinates of its center position are (0, 0, 5).

[0074] The wireless channel between any two points is represented as Where L0 = -30dB is the path loss at the reference distance (1m), d ab is the distance between two points, c=2 is the path loss factor, g ab is the small-scale fading of the channel.

[0075] The method provided by the present invention is used to obtain Figure 4 Schematic diagram of the signal-to-interference-noise ratio of the receiving node D changing with the transmission power of the interfering node J. In the figure, the anti-interference performance under the condition that the channel state information of the interfering node J is completely known is considered as the upper bound, and two cases of random reflection phase and no intelligent reflection surface R are added for comparison. The transmission power of the sending node is set to 30dBm, and the power of the interfering node J changes from 0dBm to 40dBm.

[0076] Depend on Figure 4 It can be seen that as the transmission power of the interference node J increases, the signal to noise ratio of the receiving node D drops sharply. At this time, the search-based intelligent reflection surface R reflection coefficient optimization method proposed in the present invention can almost reach the upper limit of the performance under the condition of known interference node J channel state information, which is much better than the case without intelligent reflection surface R assistance and the random reflection phase case. Figure 5 It can be observed that with the increase in the number of intelligent reflector R units, its channel control capability is further enhanced, and the interference signal reflected by it can completely offset the direct interference signal. Therefore, the receiver signal-to-interference-noise ratio does not decrease with the increase of the transmission power of the interference node J, and a good reception effect is always obtained.

[0077] In summary, the method of the present invention constructs a reflection link for the interference signal through the intelligent reflection surface, so that it cancels out the interference signal with the original interference signal, thereby greatly improving the receiving performance of the legitimate communication party, especially when there are enough reflection units on the intelligent reflection surface, the method proposed by the invention can completely cancel out the interference and achieve interference-free reception under strong interference. At the same time, the method proposed by the invention does not rely on the channel state information of the interference node, and can still achieve an anti-interference effect that is almost the same as the performance upper bound under the condition of known interference node channel state information, greatly expanding the application potential of the intelligent reflection surface in actual communication anti-interference scenarios.

[0078] The above-mentioned 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 invention patent. 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 patent of the present application shall be subject to the attached claims.

Claims

1. A smart reflective surface-assisted communication anti-interference method based on receiving feedback, characterized in that: The following steps are involved: Step 1: construct an anti-interference communication system model based on the assistance of the intelligent reflective surface, and initialize the reflection coefficient of the intelligent reflective surface; Among them, the anti-interference communication system model based on the assistance of intelligent reflective surface is specifically as follows: The system at least includes a sending node S, a receiving node D, an interference node J and an intelligent reflective surface R. When the sending node S sends a communication signal to the receiving node D, the interference node J sends an interference signal to the receiving node D to destroy its receiving effect; The intelligent reflective surface R achieves an anti-interference reception effect by offsetting the interference signal reflected and the interference signal transmitted directly; The reflection coefficient of the initialized smart reflection surface is specifically: Assume that the sending node S, receiving node D, and interference node J are all equipped with a single antenna, and the intelligent reflection surface R is equipped with N reflection units. The reflection coefficient amplitude of each reflection unit is set to its maximum value 1, and the phase is in the interval [0,2π). When initializing, the reflection coefficient phase of each reflection unit is set to n=1,...,N; Step 2: The sending node and the interference node send the communication signal and the interference signal respectively, and the receiving node measures the received signal-to-interference-noise ratio, which is recorded as Step 3: The intelligent reflective surface adjusts the reflection coefficient of each reflective unit one by one according to the feedback from the receiving node: Step 3-1: According to the reflection coefficient of the smart reflective surface R initialized in step 1, let Step 3-2: Determine the reflection coefficient phase θ of the nth reflection unit of the optimal smart reflection surface R based on the dichotomy method n : Step 3-2-1, the intelligent reflective surface R will n Set to At this time, the receiving node D measures the received signal-to-interference-noise ratio and records it as Step 3-2-2: Smart reflective surface R will θ n Set to At this time, the receiving node D measures the received signal-to-interference-noise ratio and records it as Step 3-2-3: Receiving node D compares and Determine the information fed back to the intelligent reflective surface R: like The receiving node D feeds back the bit information "000" to the smart reflective surface R; if The receiving node D feeds back the bit information "001" to the smart reflective surface R; if The receiving node D feeds back the bit information "010" to the smart reflective surface R; if The receiving node D feeds back the bit information "011" to the smart reflective surface R; if The receiving node D feeds back bit information "100" to the smart reflective surface R; if The receiving node D feeds back bit information "101" to the smart reflective surface R; Step 3-2-4: The intelligent reflector R determines θ based on the feedback information from the receiving node D. n Search interval If the smart reflective surface R receives "000" or "001", then If the smart reflective surface R receives "010" or "011", then If the smart reflective surface R receives "100" or "101", then Then, compare and like Then Step 3-2-5: The intelligent reflective surface R searches and adjusts θ in the search interval n : like Then the reflection coefficient phase of the nth reflection unit is adjusted to At this time, the receiving node D records the measured received signal-to-interference-noise ratio as like Then the reflection coefficient phase of the nth reflection unit is adjusted to At this time, the receiving node D records the measured received signal-to-interference-noise ratio as Step 3-2-6: Receiving node D calculates and The absolute value of the difference between Step 3-2-7: If Δγ n If the value is less than the set threshold ξ, repeat steps 3-2-5 and 3-2-6; otherwise, the receiving node D will Recorded as And feedback the bit information "110" to the smart reflector R. After receiving this information, the reflection coefficient phase of the nth reflector unit is adjusted to Step 3-3, let n=n+1; Step 3-4, repeat step 3-2 and step 3-3 until n=N; Step 4: Repeat step 3 until the state converges. The intelligent reflective surface performs reflection beamforming to assist in anti-interference according to the determined reflection coefficients of each reflective unit: Receiving node D calculates and The absolute value of the difference between If it is less than the set threshold σ, then terminate; otherwise, let And repeat step 3.

2. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to claim 1 are implemented.

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