Heterogeneous multi-mode multi-hop covert communication method based on single-hop opportunistic interference and intelligent reflecting surface cooperation

Abstract

This invention discloses a heterogeneous multimode multi-hop covert communication method based on single-hop opportunistic jamming and intelligent reflector collaboration, comprising the following steps: establishing a covert communication system model; for each candidate single hop, dynamically controlling the activation and deactivation of the jammer according to a set jamming threshold and instantaneous channel state; in the single hop with jamming enabled, using intelligent reflector phase matching to ensure that the reflected signal and the direct signal are superimposed in phase at the receiving end to maximize the received signal power; jointly optimizing the transmission and jamming power to maximize single-hop throughput while satisfying the covertness constraint; screening available single hops and their communication modes that meet the covertness requirements in the network, and selecting the optimal mode for each single hop; constructing a directed graph based on available single hops, using single-hop throughput as the edge weight, and selecting the end-to-end transmission path that maximizes the throughput while minimizing the path length. This invention achieves overall optimization of end-to-end throughput performance and low detectability.

Description

Technical Field

[0001] This invention relates to the field of covert communication technology, specifically to a heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector collaboration. Background Technology

[0002] While traditional physical layer security methods can improve information security, they cannot completely conceal the existence of communication. When passive eavesdroppers with advanced channel estimation and power detection capabilities exist in the network, relying solely on power convergence or random access strategies is insufficient to guarantee low detectability. In recent years, researchers have proposed using friendly interference to provide cover for legitimate links: jammers emit artificial noise to reduce the probability of detection by eavesdroppers. However, common jammer distribution models often employ Poisson point processes, ignoring the correlations caused by node repulsion or spatial resource conflicts in actual deployments. This leads to overly idealized estimations of interference power distribution, making it difficult to achieve the expected concealment gain in high-density or interference-repulsive scenarios. Meanwhile, smart reflectors, with their programmable metasurface unit arrays, provide low-power, reconfigurable control methods for wireless links. However, existing work mostly focuses on single-hop or double-hop scenarios, aiming at jointly optimizing transmit power and IRS phase. Once extended to heterogeneous multi-mode multi-hop networks, traditional joint optimization often becomes too complex to implement.

[0003] In multi-hop forwarding and multi-mode cooperative architectures, the selection of routing nodes, frequency bands, and modulation schemes significantly affects end-to-end detectability and throughput. Existing research often takes maximizing connectivity or minimizing energy efficiency as the sole objective, neglecting the synchronous guarantee of concealment constraints and throughput requirements; at the same time, most schemes treat interference and IRS as independent optimization objects, without considering that the two can complement and cooperate in the spatial and temporal domains. Summary of the Invention

[0004] Purpose of the Invention: The purpose of this invention is to provide a heterogeneous multimode multi-hop covert communication method based on single-hop opportunistic jamming and intelligent reflector collaboration. This method is designed for heterogeneous multimode multi-hop scenarios and simultaneously achieves the following: considering the jammer's rejection characteristics and rationally setting the opportunistic jamming threshold; utilizing IRS-based phase alignment to improve effective channel gain; and integrating routing and resource allocation at the network level to optimize end-to-end throughput while meeting covert constraints. This addresses the shortcomings of existing technologies in areas such as interference modeling, joint optimization complexity, and path bottleneck throughput control.

[0005] Technical solution: The heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination described in this invention includes the following steps:

[0006] (1) Establish a covert communication system model, including transmitter, receiver, relay node, passive eavesdropper, intelligent reflector and friendly jammer distributed according to the repulsion point process;

[0007] (2) For each candidate single hop, an opportunistic interference threshold is set based on the rejection point process. The jammer is dynamically controlled to turn on and off according to the threshold and the instantaneous channel state from the jammer to the receiver.

[0008] (3) Perform intelligent reflector phase matching on the single hop with interference enabled, and make the reflected signal and the direct signal in phase at the receiving end by adjusting the phase of each unit, so as to maximize the total power of the single hop received signal.

[0009] (4) Perform joint optimization of transmit power and interference power for a single hop to maximize the throughput of the single hop while satisfying the concealment constraint; screen available single hops and their communication modes that meet the concealment requirements in the network, and select the communication mode with the largest throughput for each available single hop;

[0010] (5) Based on the available single hops after filtering, a directed graph is established, and the end-to-end transmission path that maximizes the minimum throughput in the path is selected with the single hop throughput as the edge weight.

[0011] Furthermore, in step (1), the friendly jammers distributed according to the repulsion point process are used to reflect the spatial repulsion characteristics between jammers in actual deployment.

[0012] Furthermore, in step (2), the opportunistic interference threshold is set as follows: construct a connection interruption probability function and a detection error probability function with the threshold as the variable, and solve for the threshold value that maximizes the detection error probability under the constraint that the connection interruption probability does not exceed the preset value.

[0013] Furthermore, in step (3), the phase adjustment of the intelligent reflector is as follows: based on the phase information from the transmitter to the reflector, from the reflector to the receiver, and the direct channel, the reflection path and the direct path are phase-aligned at the receiver.

[0014] Furthermore, in step (4), the joint optimization is as follows: when interference is enabled, the transmission probability, transmission power and interference power upper limit are adjusted in a coordinated manner to maximize the expected achievable rate while satisfying the lower limit of concealment.

[0015] Furthermore, in step (4), the selection of available single hops specifically involves: for each communication mode of each single hop, determining whether its detection error probability is not lower than the preset concealment threshold; if so, marking the mode as an available mode.

[0016] Furthermore, when selecting the final communication mode for each available single hop, the mode that maximizes the throughput of that hop is selected as the final communication mode from all available modes.

[0017] Furthermore, in step (5), when constructing the directed graph, only single hops that satisfy the concealment constraint are added to the graph as edges, and the edge weight is the throughput of that hop in the final communication mode.

[0018] Furthermore, in step (5), the end-to-end path selection problem is transformed into the widest path problem of a directed graph, and solved by the improved shortest path algorithm, namely Dijkstra's algorithm, to obtain the route that maximizes the throughput of the path bottleneck.

[0019] Furthermore, bottleneck distance is used instead of path length, defined as the maximum value of the minimum edge weight on the path; after solving, the optimal path with the maximum end-to-end throughput of the multi-hop multimodal communication network is obtained under the condition of single-hop concealment, and satisfies:

[0020]

[0021] In the formula, The final optimized path chosen from Alice to Bob. This represents the actual end-to-end detection error probability under this path. No. A single hop in bandwidth The actual detection error probability.

[0022] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: By employing a rejection point process to accurately model the spatial distribution of jammers, this invention improves the effectiveness of jamming masking in high-density or node rejection scenarios. It intelligently coordinates opportunistic jamming with intelligent reflector phase modulation, enhancing legitimate links while effectively reducing the risk of detection. A hierarchical decoupled optimization framework is proposed, using a progressive process of single-hop jamming decision-IRS matching-route optimization to reduce the complexity of joint optimization of multi-hop multimodal networks and improve system deployability. Finally, under the premise of satisfying the concealment constraints of each hop, bandwidth and modes are collaboratively allocated with the goal of maximizing path bottleneck throughput, achieving overall optimization of end-to-end throughput performance and low detectability. Attached Figure Description

[0023] Figure 1 This is a flowchart of the present invention;

[0024] Figure 2 This is a communication network model diagram of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0026] like Figure 1As shown, this embodiment of the invention provides a heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector collaboration, including the following steps:

[0027] (1) Establish a multi-hop, multi-modal covert communication system model, such as Figure 2 As shown, the covert communication system model includes a transmitter Alice, several repeaters, a receiver Bob, a passive eavesdropper Willie, one or more intelligent reflectors (IRS), and friendly jammers distributed according to the repulsion point process (β-GPP). It is assumed that all nodes in the network, including Alice, Bob, and the repeaters, are equipped with the same communication technology or mode, including but not limited to different operating frequencies, bandwidths, and channel characteristics. Willie is a passive attacker equipped with a detector covering the frequency bands used by all modes in the network. Willie attempts to detect communication from Alice to Bob. It is assumed that Alice, Bob, Willie, and the jammers are all equipped with a single omnidirectional antenna. All channels use quasi-static Rayleigh fading channels, and a communication time slot consists of L channels used, where all channels remain unchanged within a time slot and become independent channels in the next time slot. The jammer's location is modeled as having an intensity of... β-GPP, to obtain the distance of each hop. Path loss index, transmit power of each transmitter The jamming power of the jammer Noise variance, transmission probability Let the acceptable lower limit of single-jump DEP be... To ensure that the presence of any communication can be concealed even against highly complex adversaries, this invention assumes that Willie is equipped with advanced channel estimation techniques for the first... A single hop, denoted as its transmitter. The receiving end is .

[0028] (2) For each candidate single hop in the multi-hop multimodal communication network In a single time slot, based on the β-GPP opportunistic jamming strategy, a threshold-based system is constructed. Connection interruption probability function with parameters Error detection probability function of passive listener ,exist If the threshold μ is not exceeded, determine whether to jump. The largest opportunistic interference threshold ; and based on the friendly jammers' reception at that hop. Instantaneous small-scale fading power and The comparison result controls the corresponding jammer to turn on / off; including the following steps:

[0029] (21) For the first hop in this multi-mode communication network Each hop employs opportunistic interference. It can be calculated as follows:

[0030]

[0031] In the formula, For the first The signal power received at a single-hop receiver from the previous level transmitter is specifically the sum of the direct link signal power from the transmitter to the receiver and the link signal power reflected from the transmitter to the receiver via the IRS. For the first The interference power received at a single-hop receiver from friendly jammers is specifically the sum of the total interference power of all friendly jammers' interference signals reaching that hop receiver and the total interference power of all jammers' interference signals reaching the receiver after being reflected by the IRS.

[0032] The intelligent reflector IRS only performs phase alignment on the effective signal from each hop transmitter to the receiver, and attenuates the interference signal. Therefore, the total interference power of all jammers' interference signals reaching the receiver at that hop after reflection by the IRS is much smaller than the total interference power of all jammers' interference signals reaching the receiver at that hop. Under this condition, we can obtain:

[0033]

[0034] hour, ; hour, 0;

[0035] Will and Substituting the above The expression, when rearranged, yields:

[0036]

[0037]

[0038]

[0039] In the formula, , It is an exponential random variable with a mean of 1. ;

[0040] Utilizing the fundamental properties of β-GPP, Specifically, it should be written as:

[0041]

[0042]

[0043] In the formula, , They are independent and identically distributed gamma random variables. Its probability density function;

[0044] Specific Substitution That is to be Opportunistic jamming is performed based on the threshold, and the jammer follows a precise distribution under β-GPP distributed architecture. ;

[0045] (22) For the first hop in this multi-mode communication network For each single jump, Willie performs a binary hypothesis test: At that time, support Willie's decision was that there was no communication between the transmitter and receiver in the one-way link. At that time, support Willie's decision, namely that he believes there is communication between the transmitter and receiver in the one-way link, wherein, The average signal strength received at Willie's location for that hop. This is the threshold for Willie to determine if communication exists during the hop;

[0046] The probability of detection errors It can be represented as:

[0047]

[0048] In the formula, This represents the probability of a false alarm. This represents the probability of a missed detection.

[0049] Will and Rewrite them as follows:

[0050]

[0051] In the formula, Let represent the cumulative distribution function of the disturbance at Willie. express The probability density function;

[0052] In this multi-hop multimodal communication network, the first... For a single hop, the Laplace transform of the signal power received by the jammer at its receiver is expressed as:

[0053]

[0054] When the interferator is distributed in a β-GPP manner, the correlation between its internal nodes leads to... It has complex expressions, while PPP has mature tools such as probabilistic generating functionals; density scaling can be used to align the two at the upper bound level, which can transform complex problems into Poisson point processes while preserving the statistical characteristics of repulsive fields. The calculation ensures accuracy while significantly reducing the difficulty of analysis; therefore, an intensity of [insert intensity here] is used. of To approximate β-GPP, where the intensity of the Poisson point process is scaled to ;

[0055] When the position of the friendly jammer follows At that time, the cumulative distribution function of the disturbance at Willie is:

[0056]

[0057] for , The upper bound of the CDF is specifically expressed as:

[0058]

[0059] for , The upper bound of CDF is specifically:

[0060]

[0061] let The upper bound of is constant at every x. Since the upper bound is equal, the scaling strength can be solved as follows: Specifically:

[0062]

[0063]

[0064] Will The function substitutes the position of the friendly interference device, which follows a Poisson point process. The cumulative distribution function of the disturbance at Willie's position is obtained by approximating it using β-GPP. The CDF, specifically:

[0065]

[0066] Will Substitution and The function can be used to obtain the β-GPP distributed interferometer. approximation;

[0067] (23) For each candidate single hop in the multi-hop multimodal communication network The single-hop detection error probability In reality, it is a function of system parameters such as bandwidth, detection threshold, noise power spectral density, and aggregated interference power;

[0068] (24) In order to optimize the parameters of each single hop in this multi-hop multimodal communication network threshold This ensures that while COP satisfies the constraints, it also enables... Maximize, set this single jump The target COP size is When the threshold is raised, it satisfies As the number of jammers increases, more jammers will transmit signals to the single-hop receiver; this will simultaneously increase the total jamming power at both the receiver and Willie, causing both COP and DEP to increase. Monotonically increasing; in order to maximize DEP without violating the COP constraint, we should... Adjust it to its maximum allowed value, even if Equal to (21) Exactly equal to the target Time corresponding Value. Due to It is about A strictly increasing function, the optimal solution The root can be quickly determined using conventional root-finding algorithms such as the bisection method.

[0069] (25) For each candidate single hop in the multi-hop multimodal communication network In the Each time slot employs an opportunistic interference threshold. After making the interference enable / disable decision, record whether a connection interruption event occurred during this time slot and the detection result of the passive eavesdropper for this hop; within the preset observation window, calculate the empirical connection interruption probability for this hop. The statistically obtained empirical probability is combined with the connection interruption probability constraint set in the code. Comparison, At that time, the opportunistic interference threshold for the next time slot can be updated using the following formula:

[0070] ,

[0071] In the formula, The preset non-negative step size factor, To predetermine the threshold search range, the above calculation yields the updated threshold. This will be used as the next time slot after the jump;

[0072] (3) For each candidate single hop in the multi-hop multimodal communication network After determining the single hop in step (2), IRS phase matching is performed, and element-by-element phase alignment is performed based on the receiver channel to obtain the optimal IRS reflection matrix for that hop. The package includes the following steps:

[0073] (31) Assume that in this multi-hop multimodal communication network, the first... The direct channel gain from transmitter to receiver for each single hop is: The jump transmitter to the IRS The channel gain of the unit is , IRS Section The reflection coefficient of the unit is , IRS Section The channel gain from the unit to the receiver at this hop is To maximize the total power of the received signal, the direct path signal and the reflected path signal should be superimposed in phase at the receiver. This requires adjusting the phase of each reflection unit in the IRS so that the phase of the reflected path signal is consistent with the phase of the direct path signal.

[0074] (32) For each candidate single hop in this multi-hop multimodal communication network Its IRS The phase of the signal on the reflection path of the unit changes from the transmitter to the IRS. Phase of the channel gain of the unit, IRS number The phase of the unit's reflection coefficient, IRS number The phase of the channel gain from the unit to the receiver at that hop is formed by superimposing the three parts, making the total phase of the reflection path equal to that of the direct path. The phases are equal, thus we obtain The expression for the phase is as follows:

[0075] (33) Using the reflection coefficient obtained by the solution phase function The first intelligent reflective surface IRS Each reflector performs phase modulation to maximize the total power of the single-hop received signal;

[0076] (4) For each candidate single hop in the multi-hop multimodal communication network After performing step (2) by making a decision based on the β-GPP opportunistic jamming strategy in a single time slot and turning jamming on / off, when a friendly jammer reaches the receiver at that hop... Instantaneous fading channel Less than or equal to the single-hop opportunistic interference threshold At this time, the opportunistic jammer is activated. Let the jamming power on the single-hop link at this moment be... obey The uniform distribution in, where ; Friendly jammer to the receiving end of the jump Instantaneous fading channel Greater than the single-hop opportunistic interference threshold At this time, the opportunistic jammer is turned off. Let the jamming power on the single-hop link at this time be... For any single hop on this multi-hop multimodal communication network All of them satisfy the condition that their interference power is greater than or equal to the lower limit. Less than the upper limit ;

[0077] (5) When opportunistic jamming is enabled, for each candidate single hop in the multi-hop multimodal communication network The expected achievable rate is optimized using the following steps:

[0078] (51) For each candidate single hop in the multi-hop multimodal communication network Assuming Willie knows the transmit power of the transmitter at that hop... Transmission probability The upper limit of the interference power of a friendly jammer and lower limit The channel coefficients follow Rayleigh fading, and their effective channel gain follows an exponential distribution; calculate the effective channel gain from the transmitter to Willie. Effective channel gain from friendly jammer to Willie and its parameters and Specifically:

[0079]

[0080]

[0081]

[0082]

[0083] In the formula, This is the direct channel from the transmitter to Willie in that time slot. For the channel from the IRS to Willie, The reflection coefficient matrix of the IRS used for this single hop. This is the channel from the transmitter to the IRS. This is the direct channel from the friendly jammer to Willie in this time slot. The channel from the friendly jammer to the IRS; It is the number of IRS units;

[0084] The formula for calculating the expected DEP in this time slot is:

[0085]

[0086] (52) Assuming the channel is used a sufficiently large number of times in a time slot, according to the strong law of large numbers, the average signal strength received by Willie in step (2) At that time In (2) At that time When the opportunistic jammer is activated, the jamming power is... obey The uniform distribution in the data, therefore the false alarm probability and detection error probability The derivations are as follows:

[0087]

[0088]

[0089] In the formula, ;

[0090] (53) For each candidate single hop in the multi-hop multimodal communication network Willie's The DEP of a time slot is given by the following formula:

[0091]

[0092] In step (52) and Substitute the specific expression The single hop in the time slot is obtained. The specific expression in the text is:

[0093]

[0094] The above results Substituting into the expected DEP calculation formula in (51) and simplifying, we obtain the specific expression for the expected DEP as follows:

[0095]

[0096]

[0097] (54) Let The concealment constraint is , This is the lower limit parameter for DEP; Regarding the given Upper limit function Represented as:

[0098]

[0099] Let the function ;use replace Parameters in ,get about The function, using the binary search method, for each Correspondingly Solve hour value upper limit of jamming power of jammer The optimal value is ;

[0100] (55) At this point, for each candidate single hop in the multi-hop multimodal communication network Use the current parameter combination The approximate achievable rate at the receiving end The maximum value is reached, specifically:

[0101]

[0102]

[0103]

[0104] In the formula, This is the direct channel from the receiver to Willie in that time slot. This is the direct channel from the transmitter to the receiver in that time slot. For the channel from the friendly jammer to the IRS, This is the channel from the transmitter to the IRS;

[0105] (56) For each candidate single hop in the multi-hop multimodal communication network , In the interval Internal time seek The maximum value is specifically expressed as: .

[0106] yes The unimodal function, i.e. exist When there is a unique maximum value, a one-dimensional search algorithm can be used to find the maximum value. The largest ; will Substitution This yields the optimized parameter combination;

[0107] (6) For each candidate single hop in the multi-hop multimodal communication network After performing step (2) by making a decision and turning the jamming on / off based on the β-GPP opportunistic jamming strategy in a single time slot, when the opportunistic jammer is off, the jamming power of the jammer is 0, and the transmit power of the transmitter is... Upper limit of transmission power Transmission probability ;

[0108] (7) Now, the single-mode single-hop link is extended to a multi-hop multi-mode communication network. Given the multi-hop multi-mode communication network, the transmitter is Alice, the receiver is Bob, and the definition is... Let be the set of all possible paths from Alice to Bob. This represents the final optimized path chosen from Alice to Bob, assuming Willie can directly reach the final optimized path. And the modality and bandwidth of each hop on the path, this case corresponds to the worst case from the perspective of concealment, and is Willie's best case;

[0109] For any end-to-end route in this multi-hop multimodal communication network, assume it contains a single hop. , For the transmitting end to the receiving end In a single-hop link, assuming that control signaling, protocol overhead ratio, bit error rate, retransmission strategy, frame structure, resource scheduling efficiency, and service transmission characteristics remain unchanged during communication data transmission, and that no additional environmental noise is added to the entire network, any one of its communication links... The maximum throughput is a single hop The minimum throughput, and The higher the expected achievable rate at each single-hop receiver, the better. The higher the actual throughput, the more opportunistic interference judgment and opportunistic interference on / off, joint optimization of transmission probability, IRS phase matrix, and jammer power have been performed on all single hops in the network under a given communication mode, so that the expected achievable rate of each single hop can be maximized.

[0110] (8) For a known multi-hop multimode communication network, with Alice as the transmitter and Bob as the receiver, in order to maximize the throughput from Alice to Bob, the specific steps for mode selection and parameter optimization for each relay transmitter and path planning in the communication network are as follows:

[0111] (81) Obtain the parameters of the multi-hop multimodal communication network: Assume that each hop in the network has the same available communication mode, denoted as set. For each candidate single hop in this multi-hop multimodal communication network Its communication mode In modal Below, the transmitting end The bandwidth limit is The lower limit is The complex channel gain from the IRS to the IRS and from the IRS to the receiver at that hop is... The channel gain to Willie is , Given the noise power spectral density, the concealment threshold for this single hop is... bandwidth is From (5) and (6), we can obtain the transmitter power of this single hop. and the approximate expected achievable rate at the receiving end ;

[0112] (82) For each candidate single hop in the multi-hop multimodal communication network Its throughput is expressed as:

[0113]

[0114]

[0115] in, For the first A single-hop transmitter In modality The allocated bandwidth, This indicates the transmit power of the transmitter in this mode. Indicates the first The total complex channel gain from a single-hop transmitter to the receiver, and from the transmitter to the receiver after reflection through the IRS; To find the single jump in (23) Enable jamming threshold The optimal solution;

[0116] (83) yes An increasing function; at the upper limit of bandwidth satisfy Optimal bandwidth allocation It should be the maximum bandwidth value, that is:

[0117]

[0118] in, It is each single jump Maximum allocatable bandwidth;

[0119] Traverse each candidate single hop in the multi-hop multimodal communication network Iterate through all available communication modes , The bandwidth is fixed as the optimal bandwidth, specifically as follows: ;

[0120] (84) For each candidate single hop in the multi-hop multimodal communication network that has undergone bandwidth optimization in (83) Iterate through all available communication modes , From the calculation of the detection error probability in step (2), we obtain the first... A single hop in bandwidth The actual detection error probability is denoted as . Compare actual concealment levels and concealment threshold are ,like If the single jump is retained as an available single jump, and the mode of the single jump is retained as an available mode, then... This mode is unavailable for this single hop. ,model None of them are satisfied This hop is not available.

[0121] (85) For the available single hops retained after (84) in this multi-hop multimodal communication network Calculate its available modes Actual throughput Specifically

[0122] After evaluating the throughput of each mode based on the derived bandwidth, the best mode exhibiting the highest throughput is selected as the final mode for that hop, specifically:

[0123]

[0124] Calculate the specific value of the maximum single-hop throughput in this mode. ;

[0125] (86) For this multi-hop multimodal communication network, it is constructed as a directed graph. The nodes in the directed graph include the source node Alice, the destination node Bob, and all potential relay nodes. The edges in the directed graph are the available single-hop links in the optimal mode after all the above processes. Only when a single-hop link After single-hop optimization (81)-(85), the corresponding edge will only be established in the graph if the performance constraint of concealment is met. If any pattern If none of the constraints can be satisfied, then the single-hop link does not exist; for each edge in the directed graph, its weight is the maximum throughput of the single-hop link corresponding to that edge. For end-to-end routing from Alice to Bob = ( ,…, The throughput of a route is the minimum throughput of all its individual hops. The end-to-end throughput is expressed as:

[0126]

[0127] The optimal path problem, which maximizes end-to-end throughput, can be transformed into the widest path problem in a directed graph. The goal of this problem is to find a path between two specified nodes that maximizes the minimum edge weights along that path. The widest path problem can be solved using Dijkstra's algorithm, replacing the traditional path length with bottleneck distance, which is defined as the maximum value of the minimum edge weight on the path. After solving this problem, the optimal path for maximizing end-to-end throughput in a multi-hop, multimodal communication network is obtained, satisfying the single-hop concealment condition.

[0128] Under the optimal path that maximizes end-to-end throughput, the actual end-to-end detection error probability satisfies:

[0129]

[0130] This invention aims to provide a heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination. Addressing issues in existing technologies such as impractical jamming modeling, lack of IRS-jamming coordination, complex multihop joint optimization, and the difficulty in balancing covertness and throughput, this invention proposes an jamming distribution model based on the β-GPP exclusion point process, an intelligent jamming-IRS coordination mechanism, and a hierarchical optimization framework. This significantly improves the anti-detection capability and link reliability of covert communication, achieving coordinated optimization of end-to-end throughput and low detectability. Furthermore, this invention can be combined with existing physical layer security technologies and dynamic routing mechanisms, providing an effective solution for the practical deployment of multihop covert communication in complex network environments.

[0131] The technical meanings of all parameters are shown in Tables 1-4.

[0132] Table 1. Technical meaning of all parameters.

[0133] ;

[0134] Table 2. Technical meaning of all parameters.

[0135] ;

[0136] Table 3. Technical meaning of all parameters.

[0137] ;

[0138] Table 4. Technical meaning of all parameters

[0139] .

Claims

1. A heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination, characterized in that, Includes the following steps: (1) Establish a covert communication system model, including transmitter, receiver, relay node, passive eavesdropper, intelligent reflector and friendly jammer distributed according to the repulsion point process; (2) For each candidate single hop, an opportunistic interference threshold is set based on the rejection point process. The jammer is dynamically controlled to turn on and off according to the threshold and the instantaneous channel state from the jammer to the receiver. (3) Perform intelligent reflector phase matching on the single hop with interference enabled, and make the reflected signal and the direct signal in phase at the receiving end by adjusting the phase of each unit, so as to maximize the total power of the single hop received signal. (4) Perform joint optimization of transmit power and interference power for a single hop to maximize the throughput of the single hop while satisfying the concealment constraint; screen available single hops and their communication modes that meet the concealment requirements in the network, and select the communication mode with the largest throughput for each available single hop; (5) Based on the available single hops after filtering, a directed graph is established, and the end-to-end transmission path that maximizes the minimum throughput in the path is selected with the single hop throughput as the edge weight.

2. The heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination as described in claim 1, characterized in that, In step (1), the friendly jammers distributed according to the repulsion point process are used to reflect the spatial repulsion characteristics between jammers in actual deployment.

3. The heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination as described in claim 1, characterized in that, In step (2), the opportunistic interference threshold is set as follows: Construct a connection interruption probability function and a detection error probability function with the threshold as variables, and solve for the threshold value that maximizes the detection error probability under the constraint that the connection interruption probability does not exceed the preset value.

4. The heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination as described in claim 1, characterized in that, In step (3), the phase adjustment of the intelligent reflector is as follows: based on the phase information from the transmitter to the reflector, from the reflector to the receiver, and the direct channel, the reflection path and the direct path are phase-aligned at the receiver.

5. The heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination as described in claim 1, characterized in that, In step (4), the joint optimization is as follows: when interference is enabled, the transmission probability, transmit power and interference power upper limit are adjusted in a coordinated manner to maximize the expected achievable rate while satisfying the lower limit of concealment.

6. The heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination according to claim 1, characterized in that, In step (4), the screening of available single hops is specifically as follows: for each communication mode of each single hop, determine whether its detection error probability is not lower than the preset concealment threshold. If so, mark the mode as an available mode.

7. The heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination as described in claim 6, characterized in that, When selecting the final communication mode for each available single hop, the mode that maximizes the single-hop throughput is selected from all available modes as the final communication mode.

8. The heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination according to claim 1, characterized in that, In step (5), when constructing the directed graph, only single hops that satisfy the concealment constraint are added to the graph as edges, and the edge weight is the throughput of the single hop in the final communication mode.

9. The heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination according to claim 1, characterized in that, In step (5), the end-to-end path selection problem is transformed into the widest path problem of a directed graph, and solved by the improved shortest path algorithm, namely Dijkstra's algorithm, to obtain the route that maximizes the throughput of the path bottleneck.

10. The heterogeneous multimode multihop covert communication method based on single-hop opportunistic jamming and intelligent reflector coordination according to claim 9, characterized in that, Using bottleneck distance instead of path length, the bottleneck distance is defined as the maximum value of the minimum edge weight on the path. After solving, the optimal path with the highest end-to-end throughput in a multi-hop multimodal communication network is obtained under the condition of single-hop concealment, and it satisfies the following: ； In the formula, The final optimized path chosen from Alice to Bob. This represents the actual end-to-end detection error probability under the path. No. A single hop in bandwidth The actual detection error probability.

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