Privacy protection charging distribution method and system in wireless rechargeable sensor network

Abstract

The invention provides a privacy protection charging distribution method and system in a wireless rechargeable sensor network, and the method comprises the following steps: obtaining a rechargeable device, a charger and a sensing task set, and constructing a charging network model; establishing a directed charging model; acquiring the positions of the rechargeable device and the sensing task, and establishing a task utility model; obtaining a quotation set of the chargeable device and the charger, and establishing an auction model; the problem of perceptual utility maximization of the rechargeable equipment under the constraint of the charging cost is formalized; based on a position discretization method and a power discretization method, determining candidate deployment positions and angles of chargers; carrying out discretization processing on the perception utility of the rechargeable equipment; and calling an algorithm to determine a charger deployment position and angle, and calculating the reward of the charger. According to the invention, a charger deployment scheme is planned for maximizing the perceptual utility of the chargeable device, and the perceptual utility of the network can be maximized under the condition of ensuring the charging price privacy of the charger and satisfying the charging cost constraint.

Description

Technical Field

[0001] The present application relates to the field of wireless rechargeable networks, and in particular to a privacy-preserving charging distribution method and system in a wireless rechargeable sensor network. Background Art

[0002] Wireless sensor networks have been developed for decades, but the batteries of network devices affect the working time of the devices, which in turn limits the life of the network. How to extend the life of the network has become a hot topic in the research of wireless sensor networks. The emergence of wireless power transmission technology has made up for this shortcoming of wireless sensor networks and created a new field - wireless rechargeable sensor networks. Wireless rechargeable sensor networks use rechargeable devices to complete their work and use wireless power transmission devices to recharge the rechargeable devices, which greatly extends the working time of the network and reduces the cost of equipment. Wireless rechargeable sensor networks have broad application prospects in smart cities, smart wearables, environmental monitoring and other fields.

[0003] At present, most of the research on wireless rechargeable sensor networks focuses on how to optimize network performance and charging performance, such as maximizing node life, maximizing charging utility, minimizing charging cost, maximizing task utility, etc. Security issues in the network cannot be ignored. Some scholars have studied the radiation safety issues in wireless rechargeable sensor networks, considering the impact of radiation on the human body, and designing network optimization solutions when the radiation does not exceed the threshold.

[0004] However, the information security of the device has not been fully studied. In fact, the chargers are controlled by different companies or individuals, and they charge fees for recharging wireless rechargeable devices. If the information of the charger is leaked, malicious users will manipulate their bids to win the bid and obtain improper benefits, which will affect the fairness of the system and make chargers unwilling to participate in the charging task, affecting the stability and sustainability of the system. Therefore, it is necessary to design a charging allocation mechanism with privacy protection to provide privacy protection for chargers while optimizing the charging allocation plan. Summary of the invention

[0005] The present application provides a privacy-preserving charging allocation method and system in a wireless rechargeable sensor network, which is used to optimize the charging allocation scheme while providing privacy protection for the charger.

[0006] In the first aspect, the present application provides a privacy-preserving charging allocation method in a wireless rechargeable sensor network, characterized in that it includes the following steps: obtaining a set of rechargeable devices, a set of chargers, and a set of tasks; determining the energy obtained by the rechargeable device from the charger based on a power conversion method; obtaining the perceived utility obtained by the rechargeable device from the perception task; if the power of the rechargeable device is lower than a set threshold, broadcasting the charging demand to the charger to obtain charging quotations submitted by multiple chargers, and calculating the corresponding remuneration; obtaining a set of charger deployment strategies that maximizes the perceived utility of the rechargeable device under the constraint of charging cost; determining the dominant strategy set and the corresponding coverage device set of multiple chargers through a position discretization algorithm; discretizing the perceived utility of the rechargeable device to determine the piecewise constant function of the task utility; and using a differential privacy charging allocation algorithm to determine the charger deployment position and angle and calculate the charger's remuneration.

[0007] By adopting the above technical solutions, the comprehensive technical means covering the acquisition of equipment, chargers and task sets, energy and utility calculation, charging demand response, strategy optimization, discretization processing and algorithm application are adopted to effectively solve the problems of lack of privacy protection and unreasonable resource allocation in charging distribution in the existing technology. Through the collaborative work of various steps, it is possible to accurately determine the charger deployment, optimize the charging distribution plan, improve the perceived utility of rechargeable devices, enhance the adaptability of the network to different scenarios, and improve the overall performance of the network while ensuring the privacy of the charger.

[0008] In combination with some embodiments of the first aspect, in some embodiments, the step of determining the energy obtained by the rechargeable device from the charger based on the power conversion method specifically includes: i From charger c j Received charging power p ij for: where d ij Indicates charger c j and rechargeable devices i The distance between is the power receiving angle of the rechargeable device, θ C is the charger power emission angle, and Respectively measure the rechargeable devices i and charger c j are two unit vectors, α and β are constants related to hardware and environment, and D represents the maximum charging distance of the charger; definition Charger for rechargeable devices j The actual energy obtained is: where μ 1 ,μ 2 ,μ3 ∈R is a constant; the upper limit of the energy received by the rechargeable device is defined as p th , given the charger deployment scheme C w , rechargeable devices i Deploy Collection C from Charger w Energy obtained from the charger in for:

[0009] By adopting the above technical solution, due to the technical means of constructing an electric power conversion model by comprehensively considering multiple factors, the charging power is calculated by considering in detail the distance, angle, unit vector and constants related to hardware and environment between the charger and the rechargeable device, which effectively solves the problems of inaccurate charging power calculation and insufficient consideration of actual influencing factors in the prior art. Furthermore, by reasonably defining the actual energy acquisition formula and the upper limit of received energy, the technical effect of accurately calculating the actual energy obtained by the rechargeable device and ensuring that the device safely and stably receives energy is achieved, which provides key data support for the subsequent reasonable planning of charger deployment and optimization of charging distribution plans.

[0010] In combination with some embodiments of the first aspect, in some embodiments, the step of obtaining the perceived utility obtained by the rechargeable device from the perception task specifically includes: defining the perception radius of the rechargeable device as R, the rechargeable device s i The task set is Where |T i | is the set T i The number of tasks; define the rechargeable devices s i From the task k The perceived utility obtained is u ik : where α t and β t are two positive constants, d ik Are rechargeable devices i and task t k Determine the distance between the rechargeable devices i The total perceived utility is:

[0011] By adopting the above technical solution, the technical means of defining perceived utility based on the positional relationship between the device and the task, determining the task coverage range of the rechargeable device by clarifying the perception radius of the rechargeable device, calculating the perceived utility of a single task in combination with the distance between the device and the task and a specific constant, and further summarizing the total perceived utility, effectively solves the problem that the existing technology cannot accurately measure the benefits of rechargeable devices performing perceived tasks and lacks a basis for task allocation. This achieves the technical effect of intuitively evaluating the comprehensive benefits of devices performing tasks within the coverage range, which helps to prioritize tasks to devices that can obtain higher total perceived utility when allocating tasks, and avoid wasting resources on low-efficiency tasks.

[0012] In combination with some embodiments of the first aspect, in some embodiments, if the power level of the rechargeable device is lower than a set threshold, a charging demand is broadcast to the charger to obtain charging quotations submitted by multiple chargers, and a corresponding remuneration is calculated, specifically comprising: if the power level of the rechargeable device is lower than the threshold, a charging request is broadcast to all chargers; obtaining any charger c that wants to participate in the charging task j Charging quotation b j ; Assume that the charging price of all chargers is [b min ,b max ], the charging quotation set submitted by all chargers is Assume the charger deployment strategy is C w , the reward set paid by the charger is G = {g 1 ,g 2 ,…,g m}, then the charger c j The utility of u j for u j =g j -e j , where g j For charger c j The reward, e j For charger c j The charging cost.

[0013] By adopting the above technical solution, introducing market competition mechanism and reasonable reward calculation technical means, broadcasting charging request when the power of rechargeable device is lower than the threshold, prompting multiple chargers to submit quotations, effectively solving the problems of lack of competition in charger selection, difficult cost control and inability to guarantee reasonable benefits of chargers in the prior art. By limiting the quotation range and calculating the charger utility (the difference between reward and cost), the technical effect of screening cost-effective chargers and optimizing charger deployment strategy is achieved. This method improves the efficiency of network resource allocation, reduces operating costs while meeting the charging needs of rechargeable devices, enhances the economy and stability of the network, and ensures that chargers can obtain reasonable rewards when participating in charging tasks, thereby encouraging chargers to actively participate, forming a virtuous circle, and improving the operating efficiency and sustainability of the entire wireless rechargeable sensor network.

[0014] In combination with some embodiments of the first aspect, in some embodiments, the step of obtaining a set of charger deployment strategies that satisfies the maximization of the perceived utility of the rechargeable device under the constraint of charging cost specifically includes: assuming the triple Indicates charger c j The k-th placement strategy of Is deployed at location from the perspective of; let all possible charger deployment strategies be Given a set of rechargeable devices S, a set of chargers C, a set of tasks T, and a budget B, there is a set of charger deployment strategies: Maximize the perceived utility of all rechargeable devices, i.e.: in A 0-1 variable representing the deployment strategy Whether it is selected, 1 means it is selected, otherwise it means it is not selected.

[0015] By adopting the above technical solution, the technical means of accurately describing the charger placement strategy with triples and building a utility maximization model in combination with multiple set constraints are adopted. The charger position and angle information are clarified through triples, which effectively solves the problem that the charger deployment strategy in the existing technology lacks precise expression and is difficult to comprehensively consider multiple factors. The model constructed by combining the rechargeable device set, charger set, task set and budget achieves the technical effect of comprehensively planning the charger deployment under the constraint of charging cost.

[0016] In combination with some embodiments of the first aspect, in some embodiments, the step of determining the dominant strategy set and the corresponding coverage device set of multiple chargers by a discretization algorithm specifically includes: dividing the plane into multiple sub-areas according to the positions and angles of the deployment of the rechargeable devices The charging range of the charger is discretized according to the discretization algorithm to determine the power level of each rechargeable device. If the rechargeable device is within the charging range of the charger, the multiple sub-areas are further divided according to the position of the rechargeable device and the discretization algorithm. If the divided sub-areas are points, the angle of the charger is adjusted to determine the dominant strategy set and the corresponding rechargeable device coverage set. If the divided sub-areas are areas, the position and angle of the charger deployed in the area are adjusted to determine the dominant strategy set and the corresponding rechargeable device coverage set.

[0017] By adopting the above technical solution, a technical means of combining position and power discretization and dynamically adjusting is adopted. By dividing the plane according to the position and angle of the rechargeable device to obtain the candidate position of the charger, and then discretizing the charging range to determine the device power level, the problem of the lack of flexibility in charger deployment and the inability to accurately adapt to device distribution and power requirements in the prior art is effectively solved. When the device is within the charging range, the sub-area is further divided according to the device position and the discrete algorithm. Regardless of whether the sub-area is a point or an area, the technical effect of accurately determining the dominant strategy set and the coverage device set can be achieved by adjusting the charger angle or the position and angle. This makes the charger deployment more in line with the actual scenario, can effectively expand the coverage of rechargeable devices, improve charging efficiency, enhance the network's adaptability to different device layouts and power demand scenarios, and ensure the stable operation of the network in various complex situations.

[0018] In combination with some embodiments of the first aspect, in some embodiments, the step of discretizing the charging range of the charger according to the discretization algorithm, determining the power level of each rechargeable device, and further dividing the multiple sub-areas according to the position of the rechargeable device and the discretization algorithm if the rechargeable device is within the charging range of the charger specifically includes the following steps: let H be the number of power division levels, Assume the power approximation error is η, and Calculated Determining a piecewise constant function for power for: Assume that the rotation angle of the rechargeable device is Rotating the rechargeable device within the angle range [0,2π] is equivalent to placing rechargeable devices at different angles, and calculate the number of sub-areas divided by all rechargeable devices.

[0019] By adopting the above technical solution, the discretization technology means of setting power division parameters and considering the rotation angle of the device is adopted. The power level is calculated by setting the number of power division levels and the approximate error, which effectively solves the problem that the power receiving situation of the rechargeable device cannot be accurately determined and the power distribution of the charger is unreasonable in the existing technology. Calculating the number of sub-areas in combination with the rotation angle amplitude of the rechargeable device is equivalent to simulating the angle conditions of multiple devices, achieving the technical effect of more accurate analysis of the charging environment and optimization of the power distribution of the charger.

[0020] In a second aspect, the present application provides a charging distribution system, which includes: one or more processors and a memory; the memory is coupled to the one or more processors, the memory is used to store computer program code, the computer program code includes computer instructions, and the one or more processors call the computer instructions to enable the charging distribution system to perform the method described in the first aspect and any possible implementation of the first aspect.

[0021] In a third aspect, the present application provides a computer program product comprising instructions, which, when executed on a charging distribution system, enables the charging distribution system to execute the method described in the first aspect and any possible implementation of the first aspect.

[0022] In a fourth aspect, the present application provides a computer-readable storage medium comprising instructions, which, when executed on a charging distribution system, enable the charging distribution system to perform the method described in the first aspect and any possible implementation of the first aspect.

[0023] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: 1. Due to the adoption of auction model technology that introduces market competition mechanism and privacy protection, the charging request is initiated by the rechargeable device, the charger quotes, the utility is calculated based on the charging cost, and the remuneration is reasonably calculated. It effectively solves the problems of unreasonable charger selection, high cost, and easy privacy leakage in the existing technology, and thus achieves the technical effects of screening cost-effective chargers, optimizing charger deployment strategies, protecting charger privacy, and improving network resource allocation efficiency.

[0024] 2. Due to the adoption of a technical means of comprehensively considering multiple factors to construct a directed charging model and a power receiving model, that is, calculating the charging power through a precise formula (taking into account factors such as distance, angle, unit vector, constant, etc.) and defining the power receiving model (including the actual energy acquisition formula and the upper limit of the received energy), the problems of inaccurate charging power calculation, unstable energy reception and inability to reasonably plan charger deployment in the prior art are effectively solved, thereby achieving the technical effect of accurately allocating charger resources according to the actual needs of the equipment, improving charging efficiency and ensuring the stable operation of rechargeable equipment.

[0025] 3. Due to the technical means of combining position discretization with power discretization to determine the deployment of chargers, including dividing the plane according to the position and angle of the rechargeable device to obtain candidate positions, discretizing the charging range to determine the power level, dividing the sub-areas again according to the relationship between the device and the charger, and adjusting the position and angle to find the optimal strategy set and coverage set, etc., the problems of inflexible and inaccurate charger deployment in the prior art, inability to adapt to complex scenarios and limited coverage are effectively solved, thereby achieving the technical effect of expanding the coverage of rechargeable devices, improving charging efficiency and optimizing charger resource allocation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flowchart of the privacy protection charging allocation method of the present invention; Figure 2 It is a schematic diagram of the network model in the present invention; Figure 3 A flowchart of an algorithm for determining candidate deployment positions and angles of a charger in the present invention; Figure 4 It is the power discretization flow chart in the present invention; Figure 5 A flowchart for extracting a dominant strategy set when the neutron region is a point in the present invention; Figure 6 A flowchart for extracting a dominant strategy set when the sub-region is a region in the present invention; Figure 7 This is a flow chart of discretization of perceived utility in the present invention; Figure 8 This is a flow chart of the differential privacy charging allocation algorithm in the present invention; Fig. 9 This is the plane segmentation result diagram in the present invention; Fig.10 It is a schematic diagram of the structure of a physical device of the charging distribution system in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to be used as limitations to the present application. As used in the specification and appended claims of the present application, the singular expressions "one", "a kind of", "said", "above", "the" and "this" are intended to also include plural expressions, unless there is a clear indication to the contrary in the context. It should also be understood that the term "and / or" used in the present application refers to and includes any or all possible combinations of one or more listed items.

[0028] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features, and in the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0029] For easier understanding, see Figure 1 , Figure 1 This is a flow chart of the privacy protection charging allocation method of the present invention.

[0030] Step (1) Suppose that on a two-dimensional plane Ω, S = {s 1 ,s 2 ,…,s n} represents the set of rechargeable devices, C = {c 1 ,c 2 ,…,c m} represents the charger set, T={T 1 ,T 2 ,…,T n} represents a task set, network diagram reference Figure 2 .

[0031] Step (2) establishes a directed charging model; based on the power conversion method, constructs a power receiving model, including the following steps: (2.1) Rechargeable devices i From charger c j Received charging power p ij for: where d ij Indicates charger c j and rechargeable devices i The distance between is the power receiving angle of the rechargeable device, θ C is the charger power emission angle, and Respectively measure the rechargeable devices iand charger c j Two unit vectors, α and β are constants related to hardware and environment, and D represents the maximum charging distance of the charger; (2.2) The energy received by a rechargeable device cannot be completely stored in its own battery. The received energy is converted and stored in the battery. Definition Charger for rechargeable devices j The actual energy obtained is: where μ 1 ,μ 2 ,μ 3 ∈R is a constant; (2.3) A rechargeable device can receive energy from multiple chargers, and the received energy is cumulative; however, the upper limit of the energy received by the rechargeable device is affected by the hardware device. The upper limit of the energy received by the rechargeable device is defined as p th Given the charger deployment scheme C w , rechargeable devices i Deploy Collection C from Charger w Energy obtained from the charger in for: Step (3) obtains the location of the rechargeable device and the sensing task and establishes a task utility model, including the following steps: (3.1) The rechargeable device deployed on the plane is responsible for completing the perception task, and the perception radius of the rechargeable device is defined as R; the rechargeable device s i The task set is Where |T i | is the set T i The number of tasks. Define the rechargeable devices i From the task k The perceived utility obtained is u ik : where α t and β t are two positive constants, d ik Are rechargeable devices i and task t k The distance between (3.2) Single rechargeable device i Can complete multiple i All sensing tasks under coverage, then the rechargeable device s i The total perceived utility is: Step (4) obtains a quotation set of rechargeable devices and chargers and establishes an auction model, including the following steps: Since the sensing task consumes the power of the rechargeable device, when the power of the rechargeable device is lower than the threshold, the rechargeable device submits a charging request to the platform through the communication channel, and the charging request will be broadcasted by the platform to all chargers. Any charger c that receives the charging request and wants to participate in the charging task j Will submit charging quote j ; Each charger c j Completing the charging task will incur a certain cost j The charging cost is determined by the driving cost, charging cost and rental cost, and the charging cost is the charger c j The personal information of the charger is only known to the charger itself; in order to obtain more utility, the charger submits a charging quotation b j Probably related to charging cost j Different; This privacy-preserving charging allocation method aims to design a real mechanism to encourage chargers to submit their charging costs, namely b j =e j ; Assume that the charging price of all chargers is [b min ,b max ]; the charging quotation set submitted by all chargers is After receiving the quotes from the chargers, the platform selects some chargers for deployment. Let the deployment strategy of the chargers be C w After completing the charging task, the platform calculates the reward of each charger, and the reward set paid by the charger is G = {g 1 ,g 2 ,…,g m}, then the charger c j The utility of u j for u j =g j -e j (6) where g j For charger c j The reward, e j For charger c j The charging cost.

[0032] Step (5) formalizes the problem of maximizing the perceived utility of rechargeable devices under the constraint of charging cost, including the following steps: Let the triple Indicates charger c j The k-th placement strategy is to use the angle Deployed in location Since a directed charging model is adopted, the charger can be deployed at any position on the two-dimensional plane at any angle [0,2π). Suppose all possible charger deployment strategies are Given a set of rechargeable devices S, a set of chargers C, a set of tasks T and a budget B, the perceived utility maximization problem is to find a set of charger deployment strategies that satisfies the budget constraint. Maximize the perceived utility of all rechargeable devices, i.e.: Wherein formula (7) represents maximizing the perceived utility of all rechargeable devices; A 0-1 variable representing the deployment strategy Whether it is selected, 1 means it is selected, otherwise it means it is not selected; constraint (7-1) means that the total reward of the selected charger cannot exceed the budget; constraint (7-2) means that only one deployment strategy can be selected for each charger.

[0033] Step (6) Based on the position discretization method and the power discretization method, the candidate deployment positions and angles of the charger are determined. The process is as follows: Figure 3 As shown, the following steps are included: (6.1) The deployment location of the rechargeable device is fixed and known in advance. Therefore, the plane can be divided into several sub-areas according to the deployment location and angle of the rechargeable device. and taking the segmented sub-areas as candidate locations for charger deployment; (6.2) The energy obtained by the rechargeable device from the charger is obtained according to formula (2), but this power is continuous within the charging range of the charger. Therefore, according to the power discretization scheme, the charging range of the charger is discretized to determine the power level of each rechargeable device. If the rechargeable device is within the charging range of the charger, then the rechargeable device and the charger are symmetrical. Therefore, according to the position of the rechargeable device and the power discretization scheme, the plane divided in step (6.1) can be further divided; if the divided sub-area is a point, go to step (6.3), otherwise go to step (6.4); (6.3) When the sub-areas divided by multiple rechargeable devices are points, the charger can only be deployed at this point. The dominant strategy set and the corresponding rechargeable device coverage set are found by adjusting the charging angle of the charger; (6.4) When multiple rechargeable devices divide the plane into regions, the charger can be deployed at any position in the region. By adjusting the position and angle of the charger in the region, the dominant strategy set and the corresponding rechargeable device coverage set are found; (6.5) Combine the dominant strategy set and the corresponding rechargeable device coverage set generated by steps (6.3) and (6.4).

[0034] For further information, see Figure 4 , Figure 4 The power discretization flow chart of the present invention is as follows, specifically, step (6.2) includes the following steps: (6.2.1) Let H be the number of power division levels, (6.2.2) Let the power approximation error be η, and Calculated (6.2.3) Piecewise constant function of power for: (6.2.4) Since the rechargeable device and the charger are symmetrical, if the rechargeable device is in two consecutive split intervals of the charger and If the charger is between two consecutive intervals of the rechargeable device, and Therefore, the number of sub-areas divided based on power division is calculated according to the location of the chargeable device; (6.2.5) Assume that the rotation angle of the rechargeable device is Rotating the rechargeable device within the angle range [0,2π] is equivalent to placing rechargeable devices at different angles; therefore, at the position of the rechargeable device s i deploy s i For the same rechargeable device, calculate the number of sub-areas divided by all rechargeable devices.

[0035] Further, such as Figure 5 As shown, step (6.3) includes the following steps: (6.3.1) Assume the charging angle of the charger is θ C ; (6.3.2) Select any charger c j ∈C is deployed at the split point o j superior; (6.3.3) Rotate the charger counterclockwise to allow any rechargeable device to i At the right edge of the charger's charging area, which is the initial position, the charger c j Candidate dominant strategy Candidate dominant strategy The covered rechargeable device collection is (6.3.4) Continue to rotate the charger counterclockwise until a new rechargeable device appears on the cj On the right boundary of the charging area, record the candidate dominant strategy of the charger and the set of rechargeable devices covered at this time; (6.3.5) Repeat step (6.3.4) until the charger rotates 360° and stops rotating; (6.3.6) Repeat steps (6.3.2)-(6.3.5) until all chargers are traversed; (6.3.7) Compare the rechargeable device coverage sets corresponding to all candidate dominant strategy sets. If there is an inclusion relationship between the sets, then retain the large set and discard the small set to obtain the charger dominant strategy set and the corresponding coverage device set.

[0036] Further, such as Figure 6 As shown, step (6.4) includes the following steps: (6.4.1) Select sub-region F ζ , select any rechargeable device pair s in the sub-area i and j ; (6.4.2) Draw a line through s i and j and extend the line to and sub-area F ζ The boundary of the device intersects and the intersection is recorded; the charger is placed at the intersection and the rechargeable device s i and j At the right boundary of the charging area of ​​the charger, the candidate dominant strategy set and the rechargeable devices covered by the candidate dominant strategy set are recorded; (6.4.3) Let the charging angle be θ C , draw two lines through s i and j The straight line is calculated, and the intersection of the straight line and the sub-area boundary is calculated; the charger is placed at the intersection, and the rechargeable device s i and j At the two boundaries of the charger's charging area, record the candidate dominant strategy set and the rechargeable devices covered by the candidate dominant strategy set; (6.4.4) Repeat steps (6.4.1), (6.4.2), (6.4.3) until sub-region F ζ All rechargeable device pairs in the region are selected; (6.4.5) randomly select sub-region F ζ A location on the border Use the dominant strategy set search method when the area is a point in step (6.3), add the obtained result as the candidate dominant strategy set, and calculate the corresponding rechargeable device coverage set; (6.4.6) Repeat steps (6.4.1)-(6.4.5) until all chargers have been traversed; (6.4.7) Compare the rechargeable device coverage sets corresponding to all candidate dominant strategy sets. If there is an inclusion relationship between the sets, then retain the large set and discard the small set to obtain the charger dominant strategy set and the corresponding coverage device set.

[0037] Step (7) Design a utility discretization scheme to discretize the perceived utility of the rechargeable device. The process is as follows: Figure 7 As shown, the following steps are included: (7.1) Let Z be the number of levels of task utility division, (7.2) Let the utility approximation error be η, and (7.3) Task utility piecewise constant function for: Step (8) calls the differential privacy charging allocation algorithm to determine the charger deployment location and angle and calculate the charger's reward. The process is as follows: Figure 8 As shown, the following steps are included: (8.1) Input the rechargeable device set S, charger set C, task set T, and quotation set Budget B, differential privacy parameters ∈ and δ, charger charging angle θ C ; (8.2) Initialize C ′ ←C, B ′ ←B, (8.3) Based on the position, energy receiving angle and direction of the rechargeable device, the two-dimensional plane is divided into a set of sub-regions F using steps (6.1) and (6.2); (8.4) Traverse and select a subregion F ζ ∈F, if the subregion F ζ If it is a point, go to step (6.3) and add the result to the candidate dominant strategy set C w '; if sub-region F ζ If it is a region, go to step (6.4) and add the result to the dominant strategy set C ′ w ; (8.5) Traverse and select a charger c j ∈C′, calculate the charger c j The selection criteria q j in Indicates charger c j All policy sets of Represents the set Cw Covered rechargeable devices, Indicates charger c j The marginal utility generated; Assume the score function is f = x, then charger c j The score f j =q j ; Calculate charger c j The probability of being selected is Pr j (b j )for in Δb=b max -b min , is the maximum utility of the device, e is a natural constant; (8.6) According to the probability distribution obtained in step (8.5), randomly select a charger c j ′; (8.7) Calculate the charger c j ′Reward g j ′ : and move the compensation from budget B ′ Subtract from B ′ =B ′ -g j ′ , if B ′ >0, jump to (8.8), otherwise jump to (8.9); (8.8) replace the charger c in formula (10) j ′ corresponds to the strategy set Join C w In, charger c j ′ The reward j ′ Add to G, and place the charger c j ' is deleted from C', and c j All dominant strategy sets corresponding to ′ are from C w ' is deleted; (8.9) Return to C w ,G; (8.10) Repeat steps (8.5)-(8.9) until Return to C w ,G; or meet the conditions of step (8.9).

[0038] Through the above method, the following beneficial effects can be achieved: 1. This invention considers the impact of charger quotation privacy protection and the budget constraint of rechargeable devices, proposes the charging utility maximization problem, and designs a charger deployment scheme for this problem, which can achieve at least Probability guarantee performance, where OPT is the utility generated by the optimal solution.

[0039] 2. The maximum number of sub-areas generated by n rechargeable devices in step (6.1) is 5n 2 -5n+2.

[0040] 3. The maximum number of sub-areas generated by n rechargeable devices in step (6.2) is in

[0041] Step (6.2.1) divides the receiving area of ​​the rechargeable device into H sub-areas, and step (6.2.5) further divides the area into blocks, then n rechargeable devices can have at most The blocks overlap each other. According to the conclusion in 2, the number of sub-areas generated by n rechargeable devices in step (6.2) is at most in

[0042] 4. The set of candidate dominant strategies generated by steps (6.3) and (6.4) for any sub-region is O(n 2 ).

[0043] Step (6.4) requires traversing any pair of rechargeable devices in the sub-area. The maximum number of rechargeable devices in each sub-area is n, so the maximum number of rechargeable device pairs is Each rechargeable device pair can generate O(1) candidate dominant strategy sets; the n rechargeable devices in step (6.3) can generate at most O(n) candidate dominant strategy sets, so the number of candidate dominant strategy sets generated by steps (6.3) and (6.4) for any sub-region is at most O(n 2 ).

[0044] 5. The number of dominant strategy sets obtained in step (6) is Where n is the number of rechargeable devices, η is the power approximation error, Angle adjustment parameters.

[0045] According to 3, the maximum number of sub-regions is Scaling H to O(η -1 ), then the number of segmented sub-regions is Combining 4, the number of final candidate dominant strategy sets is

[0046] 6. The power approximation error in step (6.2) is

[0047] Discuss the following two situations: Case 1: Power p ij With the distance d ij decreases with the increase of otherwise, Case 2:

[0048] 7. The perceived utility approximation error obtained in step (7) is

[0049] According to formula (4), we have Then the approximate task utility is Discuss the following two situations: Case 1: Task utility ik With the distance d ik decreases with the increase of Otherwise there is (1+η) 2 ,in Obtained from (6); Case 2: have

[0050] 8. The differential privacy charging allocation algorithm designed in step (8) ensures the rationality of individual chargers.

[0051] If the charger is not selected, the utility is 0; j Selected, c j The reward is Therefore, all chargers can obtain non-negative utility and ensure individual rationality.

[0052] 9. The differential privacy charging allocation algorithm designed in step (8) is real.

[0053] Step (8.5) calculates the probability of each charger being selected, probability Pr j (b j ) With the quotation b j The growth of is monotonically decreasing, and the upper limit of the charger's quotation does not exceed b max , then there is Chargerj ∈C w The expected reward that can be obtained is Therefore, the differentially private charge allocation algorithm is real.

[0054] 10. The differential privacy charging allocation algorithm designed in step (8) can achieve Differential privacy, where ∈>0.

[0055] set up and For two different inputs, both chargers are c j The quotation of is different. The placement strategy for any number of chargers is So and The corresponding output probability is in

[0056] Consider the following two cases: Case 1: For any charger c p ∈C q , q∈[1,t], let b ′ p >b p , then there is Then there is Case 2: For any charger c p ∈C q , q∈[1,t], let b ′ p ≤ b p , then there is Then there is and

[0057] Let Y be the space of all possible outputs, and C w ∈Y. Split Y into two parts Y 1 and Y 2 ,and Y 2 =Y\Y 1 Then there is

[0058] 9. The differential privacy charging allocation algorithm designed in step (8) can be used with at least The probability of obtaining The utility of min A is the smallest quote for the charger, and B is the budget.

[0059] Assume that the optimal charger placement set is The charger deployment set obtained by the differential privacy charging allocation algorithm is For any charger c j ∈C w The utility that can be obtained is For any charger c j ′ ∈C OPT The utility that can be obtained is According to the existing theorem, we have Assume t = O(ln m), then the maximum The probability of satisfying Among them C max The maximum utility of the selected charger set is the ability to charge at least The probability of satisfying: C OPT The utility of the chargers in the Therefore, there is According to (7), we can get Then there is

[0060] The above content is further described below in conjunction with specific scenarios. This embodiment takes a wireless rechargeable device network as an example. The privacy protection charging allocation method includes the following steps: On the two-dimensional plane Ω, on the two-dimensional plane Ω, S = {s 1 ,s 2 ,…,s n} represents the set of rechargeable devices, C = {c 1 ,c 2 ,…,c m} represents the charger set, T={T 1 ,T 2 ,…,T n} represents the task set. The coordinates of the above devices are shown in Table 1.

[0061] Table 1 Parameters of rechargeable devices Table 2 Task parameters Rechargeable devices coordinate <![CDATA[t 1 ]]> (-10，10) <![CDATA[t 2 ]]> (-6，0) <![CDATA[t 3 ]]> (14，0) <![CDATA[t 4 ]]> (10，6) <![CDATA[t 5 ]]> (6，16) <![CDATA[t 6 ]]> (30，20) <![CDATA[t 7 ]]> (32，6) <![CDATA[t 8 ]]> (50，-6) Charger parameters: The charger has 3 c 1 ,c 2 and c 3 The quotations are b 1 =3, b 2 =4, b 3 =5.

[0062] The charging related parameters are set as: α=50, β=10, D=20, θ C =π,μ 1 =-0.00001, μ 2 =0.57, μ 3 =10, p th =1,α t =100,β t =20, R=15, B=10.

[0063] Privacy parameters: ∈ = 0.5, δ = 0.01; (6.1) According to the position and angle of the rechargeable device, the plane can be divided into 9 sub-areas; (6.2) Discretize the power of the charger according to the power discretization scheme; (6.2.1) Set the number of power division levels H = 2; (6.2.1) Set the approximation error η = 0.1; (6.2.3) Piecewise constant function of power for (6.2.4) Dividing the plane using the rechargeable device and the set number of power divisions based on the symmetry between the rechargeable device and the charger; (6.2.5) Assume that the rotation angle of the rechargeable device is Therefore, it is equivalent to having only one rechargeable device at the location of each rechargeable device, so the area can be divided into 15 sub-areas, of which sub-areas 15 and 16 are point areas, and the rest are irregular areas, such as Fig. 9 As shown; (6.3) extracting the dominant strategy for the sub-regions where the region is a point; (6.3.1) Charging angle θ of the charger C =π; (6.3.2) Select any charger c 1 Deployed in point area 16; (6.3.3) When the angle is 0°, the rechargeable device s 2 and 3 In c 1 On the right boundary of (6.3.4) Continue to rotate the charger. When the charger is rotated to 180°, the chargeable device s 1 On the right edge of the charger, (6.3.5) Continue rotating the charger until no new dominant strategy set can be found after rotating 360°; (6.3.6) Traverse charger c 2 and c 3 , we can get (6.3.7) By comparing the dominant strategy sets, it is found that the two candidate dominant strategy sets of each charger are the same, so only one is retained, that is, (6.4) When the sub-region is an irregular plane, the dominant strategy is extracted; (6.4.1) Select sub-area 10, select sub-area charging device pair s 2 and 3 ; (6.4.2) Draw a line through s 2 and 3 The straight line is extended to intersect the boundary of sub-area 10, two intersection points are recorded, and the rechargeable device s 2 and 3 Place it on the charger c 1 The right boundary of the charging area, the candidate dominant strategy set (6.4.5) Let the charging angle θ C =π, draw two lines through s 2 and 1 The straight line and sub-area 10 have one intersection point. At this time, the candidate dominant strategy set is (6.4.4) Select the sub-area rechargeable device pairs s respectively 2 and 3 and 1 and 3, we can get the candidate dominant strategy set (6.4.5) Arbitrarily select a position (10, 0) on the boundary of subregion 10 and use the method in step (6.2) to propose a candidate dominant strategy set (6.4.6) Traverse charger c 2 and c 3 , we can get and c 1 Same result; (6.4.7) Comparing the candidate dominant strategy sets, we can get (6.5) Comparing the results of (6.3) and (6.4), the final set of dominant strategies retained is (7.1) Let the number of levels of task utility division be Z = 2, (7.2) Assume that the utility approximation error η = 0.1, (7.3) Task utility piecewise constant function for: (8.1) Input the rechargeable device set S, charger set C, task set T, and quotation set Budget B, differential privacy parameters ∈ and δ, charger charging angle θ C ; (8.2) Initialize C ′ ←C, B ′ ←B, (8.3) Based on the position of the rechargeable device, the energy receiving angle and direction, the plane can be divided into the following parts using steps (6.1) and (6.2): Fig. 9 The 16 sub-regions shown; (8.4) Traverse the sub-region F ζ ∈F, calculate the charger c 1 The candidate dominant strategy set C w ', the results are shown in Table 3: Table 3: Candidate dominant strategy set Charger 2 and c 3 The results obtained are the same; (8.5) Select a charger c 1 , charger c1 Selection criteria You can also get The partition function is f = x, so f 1 =q 1 , then the charger c 1 The probability of being selected is Pr 1 (b 1 )=0.334,Pr 2 (b 2 )=0.333,Pr 3 (b 3 )=0.333; (8.6) Randomly select a charger c 1 ; (8.7) Calculate the charger c 1 The reward 1 =3.87; B ′ =B ′ -g 1 =6.13, B ′ >0, jump to (8.8); (8.8) c 1 The strategy set c 1 11 ={c 1 ,(20,0),0°} added to C w In, g 1 Add to G, and charger c 1 Delete from C' and change c 1 The corresponding set of all dominant strategies from C w ' is deleted; (8.10) Repeat steps (8.5)-(8.7) and select charger c for the second time. 2 , g 2 =4.42; choose charger c for the third time 3 When B ′ <0, go to step (8.9), return G = {g 1 ,g 2}, the corresponding total perceived utility is: 0.425.

[0064] The embodiments described above are intended to help readers understand the principles of the present invention, but the protection scope of the present invention is not limited thereto. Various other substitutions or modifications made by technicians in this field based on the technical solutions disclosed by the present invention without departing from the essence of the present invention are all within the protection scope of the present invention.

[0065] The following describes the charging distribution system in the embodiment of the present invention from the perspective of hardware processing. Fig.10 , which is a schematic diagram of a physical device structure of a charging distribution system in an embodiment of the present application.

[0066] It should be noted that Fig.10 The structure of the charging distribution system shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0067] like Fig.10 As shown, the charging distribution system includes a central processing unit (CPU) 1001, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 1002 or the program loaded from the storage part 1008 to the random access memory (RAM) 10010, such as executing the method described in the above embodiment. In the RAM 10010, various programs and data required for system operation are also stored. The CPU 1001, the ROM 1002 and the RAM 10010 are connected to each other through the bus 1004. The input / output (I / O) interface 1005 is also connected to the bus 1004.

[0068] The following components are connected to the I / O interface 1005: an input section 1006 including an audio input device, a button switch, etc.; an output section 1007 including a liquid crystal display (LCD) and an audio output device, an indicator light, etc.; a storage section 1008 including a hard disk, etc.; and a communication section 1009 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 1009 performs communication processing via a network such as the Internet. A drive 1010 is also connected to the I / O interface 1005 as needed. A removable medium 1011, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1010 as needed so that a computer program read therefrom is installed into the storage section 1008 as needed.

[0069] In particular, according to an embodiment of the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product, which includes a computer program carried on a computer readable medium, and the computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through the communication part 1009, and / or installed from a removable medium 1011. When the computer program is executed by the central processing unit (CPU) 1001, various functions defined in the present invention are performed.

[0070] It should be noted that specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.

[0071] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present invention. Each box in the flowchart or block diagram may represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box may also occur in an order different from that marked in the accompanying drawings.

[0072] Specifically, the charging distribution system of this embodiment includes a processor and a memory, and a computer program is stored in the memory. When the computer program is executed by the processor, the privacy protection charging distribution method in the wireless rechargeable sensor network provided in the above embodiment is implemented.

[0073] As another aspect, the present invention further provides a computer-readable storage medium, which may be included in the charging distribution system described in the above embodiment; or may exist independently without being assembled into the charging distribution system. The above storage medium carries one or more computer programs, and when the above one or more computer programs are executed by a processor of the charging distribution system, the charging distribution system implements the privacy protection charging distribution method in the wireless rechargeable sensor network provided in the above embodiment.

[0074] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0075] As used in the above embodiments, the term "when..." may be interpreted to mean "if..." or "after..." or "in response to determining..." or "in response to detecting...", depending on the context. Similarly, the phrases "upon determining..." or "if (the stated condition or event) is detected" may be interpreted to mean "if determining..." or "in response to determining..." or "upon detecting (the stated condition or event)" or "in response to detecting (the stated condition or event)", depending on the context.

[0076] Those skilled in the art can understand that to implement all or part of the processes in the above-mentioned embodiments, the processes can be completed by computer programs to instruct related hardware, and the programs can be stored in computer-readable storage media. When the programs are executed, they can include the processes of the above-mentioned method embodiments. The aforementioned storage media include: ROM or random access memory RAM, magnetic disk or optical disk and other media that can store program codes.

Claims

1. A privacy-preserving charging allocation method in a wireless rechargeable sensor network, characterized in that: The method comprises the following steps: obtaining a set of rechargeable devices, a set of chargers and a set of tasks; Determine the energy obtained by the rechargeable device from the charger based on the power conversion method; Obtaining the perceived utility obtained by the rechargeable device from the sensing task; If the power level of the rechargeable device is lower than the set threshold, the charging demand is broadcast to the charger to obtain charging quotes submitted by multiple chargers and calculate the corresponding remuneration; Obtain a set of charger deployment strategies that maximize the perceived utility of rechargeable devices under the constraints of charging cost; Determine the dominant strategy set and corresponding coverage device set of multiple chargers through the location discretization algorithm; Discretize the perceived utility of the rechargeable device to determine the piecewise constant function of the task utility; Using the differential privacy charging allocation algorithm, the charger deployment location and angle are determined and the charger remuneration is calculated.

2. The privacy-preserving charging allocation method in a wireless rechargeable sensor network according to claim 1, characterized in that: The step of determining the energy obtained by the rechargeable device from the charger based on the power conversion method specifically includes: Rechargeable devices i From charger c j Received charging power p ij for: where d ij Indicates charger c j and rechargeable devices i The distance between S is the power receiving angle of the rechargeable device, θ C is the charger power emission angle, and Respectively measure the rechargeable devices i and charger c j Two unit vectors, α and β are constants related to hardware and environment, and D represents the maximum charging distance of the charger; definition Charger for rechargeable devices j The actual energy obtained is: Where μ1, μ2, μ3∈R are constants; Define the upper limit of the energy received by the rechargeable device as p th , given the charger deployment scheme C w , rechargeable devices i Deploy Collection C from Charger w Energy obtained from the charger in for:

3. According to the privacy-preserving charging allocation method in a wireless rechargeable sensor network of claim 1, the step of obtaining the perceived utility obtained by the rechargeable device from the perception task specifically comprises: Define the perception radius of the rechargeable device as R, and the rechargeable device s i The task set is T i ={t1,t2,…,t |Ti| }, where |T i | is the set T i The number of tasks; Defining Rechargeable Devices i From the task k The perceived utility obtained is u ik : where α t and β t are two positive constants, d ik Are rechargeable devices i and task t k The distance between Identify rechargeable devices i The total perceived utility is:

4. According to the privacy-preserving charging allocation method in a wireless rechargeable sensor network of claim 1, if the power level of the rechargeable device is lower than a set threshold, the charging demand is broadcast to the charger to obtain charging quotations submitted by multiple chargers, and the corresponding remuneration is calculated, which specifically includes: If the charge level of the rechargeable device is lower than the threshold, a charging request is broadcast to all chargers; Get any charger c that wants to participate in the charging task j Charging quotation b j ; Assume that the charging price of all chargers is [b min ,b max ], the charging quotation set submitted by all chargers is Assume the charger deployment strategy is C w , the reward set paid by the charger is G = {g1,g2,…,g m }, then the charger c j The utility of u j for u j =g j -e j , where g j For charger c j The reward, e j For charger c j The charging cost.

5. The privacy-preserving charging distribution method in a wireless rechargeable sensor network according to claim 1, characterized in that: The steps of obtaining a set of charger deployment strategies that maximize the perceived utility of rechargeable devices under the constraints of charging costs specifically include: Let triple Indicates charger c j The k-th placement strategy of Is deployed at location Angle Assume that all possible charger deployment strategies are Given a set of rechargeable devices S, a set of chargers C, a set of tasks T, and a budget B, there is a set of charger deployment strategies: Maximize the perceived utility of all rechargeable devices, i.e.: in A 0-1 variable representing the deployment strategy Whether it is selected, 1 means it is selected, and 0 means it is not selected.

6. The privacy-preserving charging distribution method in a wireless rechargeable sensor network according to claim 1, characterized in that: The step of determining the dominant strategy set of multiple chargers and the corresponding coverage device set by a discretization algorithm specifically includes: dividing the plane into multiple sub-areas according to the positions and angles of the deployment of the rechargeable devices Discretize the charging range of the charger according to the discretization algorithm, determine the power level of each rechargeable device, and if the rechargeable device is within the charging range of the charger, further divide the multiple sub-areas according to the position of the rechargeable device and the discretization algorithm; If the divided sub-area is a point, the angle of the charger is adjusted to determine the dominant strategy set and the corresponding rechargeable device coverage set; if the divided sub-area is an area, the position and angle of the charger deployed in the area are adjusted to determine the dominant strategy set and the corresponding rechargeable device coverage set.

7. The privacy-preserving charging allocation method in a wireless rechargeable sensor network according to claim 1, characterized in that: The step of discretizing the charging range of the charger according to the discretization algorithm, determining the power level of each rechargeable device at the location, and further dividing the multiple sub-areas according to the location of the rechargeable device and the discretization algorithm if the rechargeable device is within the charging range of the charger, specifically includes the following steps: Let H be the number of power division levels, Assume the power approximation error is η, and Calculated Determining a piecewise constant function for power for: Assume that the rotation angle of the rechargeable device is Δθ S , rotating the rechargeable device within the angle range [0,2π] is equivalent to placing rechargeable devices at different angles, and calculate the number of sub-areas divided by all rechargeable devices.

8. A charging distribution system, characterized in that: The charging distribution system includes: one or more processors and a memory; the memory is coupled to the one or more processors, the memory is used to store computer program code, the computer program code includes computer instructions, and the one or more processors call the computer instructions to enable the charging distribution system to execute the method as described in any one of claims 1-7.

9. A computer program product comprising instructions, characterized in that When the computer program product is executed on a charging distribution system, the charging distribution system is caused to perform the method according to any one of claims 1 to 7.

10. A computer-readable storage medium comprising instructions, characterized in that: When the instructions are executed on a charging distribution system, the charging distribution system is caused to perform the method according to any one of claims 1 to 7.

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