A multi-path communication guarantee system of a power internet of things terminal

Abstract

The application discloses a kind of multi-path communication guarantee system of electric power internet of things terminal, it is related to multi-path communication technical field, for solving the problem of the problem that the stability of path is ignored by only considering network cost, and ignoring the path stability, by dynamically evaluating the quality and energy consumption efficiency of each link, flexibly selecting wireless or PLC communication technology, minimum spanning tree algorithm is operated for wireless and PLC link network, the optimized backbone structure is constructed in respective network, by detecting and completing the distortion node pair in network, the network instability caused by link quality fluctuation and network topology change is repaired, the cost and stability of pure wireless path, pure PLC path and mixed path are calculated, the most suitable path is selected between source node and destination node.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of multipath communication, more particularly, the present application relates to a kind of multipath communication guarantee system of power internet of things terminal. BACKGROUND

[0002] The existing power internet of things terminal multipath communication guarantee system technology usually combines multiple path routing, link quality evaluation, communication technology fusion and redundancy mechanism and other methods.Although these technologies effectively guarantee the stability and reliability of network communication in many scenarios, there are still certain technical challenges in dynamic adaptability, cross-layer optimization and intelligent switching between multiple communication modes.

[0003] The prior art has the following disadvantages:

[0004] Most of the existing solutions rely on a single wireless or PLC communication method, which cannot fully utilize the complementary advantages of both communication technologies.This design improves the flexibility and reliability of the network by fusing wireless and PLC communication technologies.The link selection in traditional solutions often does not consider energy efficiency and quality fluctuations, while this solution introduces a comprehensive evaluation of energy-bandwidth ratio and link quality index, effectively improving network performance. Ignoring the impact of link fluctuations on the backbone network can lead to distortion or instability in the backbone network. The introduction of the distortion edge compensation module effectively solves this problem. Traditional path selection algorithms often only consider network cost, while ignoring path stability. The design of the optimal path selection module considers both path cost and stability, ensuring long-term stable operation of the network.

[0005] To solve the above problems, the present application provides a solution. SUMMARY

[0006] To overcome the above-mentioned defects of the prior art, embodiments of the present application provide a multipath communication guarantee system for power internet of things terminal to solve the problems raised in the background art.

[0007] To achieve the above-mentioned purposes, the present application provides the following technical solutions:

[0008] A multipath communication guarantee system for power internet of things terminal, comprising: a hybrid topology construction module, a backbone sketch generation module, a distortion edge compensation module and an optimal path selection module, the modules are signal connected;

[0009] The hybrid topology construction module: constructs a wireless+PLC fusion network topology structure, calculates the advantages of wireless communication and PLC communication according to the link quality index and energy-bandwidth ratio of each link, selects the corresponding communication technology, divides the link into wireless link, PLC link and dual stack link, and applies node link upper limit constraint to construct wireless and PLC link set respectively;

[0010] Backbone skeleton generation module: extract wireless communication and PLC communication link subnets respectively, set different weights, use MST to run minimum spanning tree algorithm on each subnet, and generate wireless communication and PLC communication backbone network skeleton respectively;

[0011] Distortion edge filling module: traverse the node pairs of the wireless communication and PLC communication backbone network skeleton, detect the distorted node pairs in the backbone network skeleton, select "single-source batch" or "global revenue sorting" completion strategy according to the link quality fluctuation and distortion pair density, and generate complete wireless communication and PLC communication backbone tree;

[0012] Optimal path selection module: calculate the total path cost and path stability of pure wireless path, pure PLC path and mixed path from the source node to the destination node, and select the optimal multi-hop communication path through closeness analysis method.

[0013] In a preferred embodiment, the following is included:

[0014] The n nodes of the power internet of things terminal are combined in pairs to be considered as potential one-hop communication links, and all potential links are subjected to feasibility screening according to preset conditions; wherein when the geometric distance between two nodes is less than or equal to the preset maximum wireless communication distance, it is determined that the link is feasible for wireless communication, and when the length of the in-phase power line between two nodes is less than or equal to the preset upper limit of the line feasibility, it is determined that the link is feasible for PLC communication; the screened links are preliminarily classified according to medium feasibility: links that only meet the condition of wireless communication feasibility are marked as wireless links, links that only meet the condition of PLC communication feasibility are marked as PLC links, and links that meet the conditions of wireless and PLC communication feasibility are marked as dual-use links; the link quality index LQI and the energy-bandwidth ratio EBR parameters are obtained for each potential link that meets the conditions of wireless and PLC communication, the smaller value of the bidirectional LQI values of the link is taken as the LQI evaluation value of the link, and the EBR evaluation value of the link is obtained; based on the LQI evaluation value and the EBR evaluation value, the advantages of the link in wireless communication mode and PLC communication mode are calculated; the wireless communication advantage score and the PLC communication advantage score are compared, and the link type is determined according to the predetermined criteria:

[0015] If the wireless communication advantage score and the PLC communication advantage score are both 0, it is determined that the link cannot establish reliable communication under both media, the link is discarded and not included in the network topology;

[0016] If the wireless communication advantage score is greater than the preset multiple threshold of the PLC communication advantage score, the link is determined as a wireless link, and subsequent communication is preferentially transmitted via the wireless channel; if the PLC communication advantage score is greater than the preset multiple threshold of the wireless communication advantage score, the link is determined as a PLC link, and subsequent communication is preferentially transmitted via the power line channel;

[0017] Otherwise, when the difference between the advantage scores of the two communication modes does not exceed the preset multiple threshold, it is determined that the wireless and PLC performances of the link are similar, the link is marked as a dual stack link, and the dual stack link is capable of supporting dynamic switching or parallel redundant use of the wireless and PLC communication modes; an upper limit value of the number of wireless link connections and an upper limit value of the number of PLC link connections are respectively set for each node, for limiting the maximum number of links of a single node in the wireless communication and PLC communication modes; for the set of wireless links and dual stack links, the available wireless directional links of each node are sorted according to the wireless communication advantage scores in descending order, and a plurality of wireless links with the highest advantage scores are preferentially reserved, so that the number of wireless links of each node does not exceed the upper limit value of the wireless link connections;

[0018] For the set of PLC links and dual stack links, the available PLC directional links of each node are sorted according to the PLC communication advantage scores in descending order, a plurality of PLC links with the highest advantage scores are preferentially reserved, so that the number of PLC links of each node does not exceed the upper limit value of the PLC link connections; after the links exceeding the upper limit are pruned, a set of wireless links and a set of PLC links are formed as the initial topology of the wireless subnetwork and the initial topology of the PLC subnetwork respectively, and all nodes in the initial topology of the wireless subnetwork and the initial topology of the PLC subnetwork satisfy the respective node link number upper limit constraint;

[0019] In a preferred embodiment, the following is included:

[0020] Different link weight indicators are set according to the differences between the wireless communication and PLC communication medium characteristics: for a wireless link, a parameter capable of reflecting transmission energy consumption or transmission delay is selected as the weight; for a PLC link, a parameter capable of reflecting the power line channel noise level or link reliability is selected as the weight; the minimum spanning tree algorithm is respectively applied in the initial topologies of the wireless communication and PLC communication subnetworks to select the backbone transmission links, and the wireless communication and PLC communication backbone network prototypes covering all nodes and having the minimum total wireless link weight are generated.

[0021] In a preferred embodiment, the following is included:

[0022] For any two nodes i and j in the backbone network prototype, the multi-hop communication path cost between the two nodes is The shortest path cost between the two nodes i and j is , if there is wherein, γ is a preset distortion threshold coefficient, it is determined that the node pair produces communication distortion under the current backbone network sketch, and all node pairs satisfying the condition are recorded as distortion pairs; all nodes in the backbone network sketch are traversed, and the number of distortion pairs involved by each node as an endpoint is counted and recorded as the distortion degree of the node; the average value and the standard deviation of the distortion degrees of all nodes are calculated, and a node set with a distortion degree higher than the sum of the average value and the standard deviation and with a corresponding node accounting for no more than a preset proportion of the total number of nodes is recorded as a high-distortion center node set C; and the Gini coefficient is calculated in combination with the difference between the distortion degrees of all nodes;

[0023] The single-source batch edge supplement is adopted only when the number of nodes in the set C does not exceed a preset percentage of the total number of network nodes and when the Gini coefficient is greater than a preset coefficient threshold;

[0024] For each center node in the set C, a number of direct edges are supplemented to the node at one time to simultaneously solve the detour problem of the node and a plurality of neighbors;

[0025] In other cases, the overall distortion gap is considered to be scattered, and the global benefit ranking edge supplement is adopted;

[0026] All candidate links are ranked according to the benefits of improving the paths of the entire network, and are sequentially added to the backbone, and the benefits are updated until the distortion pairs are eliminated or the upper limit of the edge supplement is reached;

[0027] The complete wireless communication and PLC communication backbone tree is generated using the single-source batch or global benefit ranking supplement strategy;

[0028] In a preferred embodiment, the following is included:

[0029] A pure wireless path forwarded only via a wireless backbone network link, a pure PLC path forwarded only via a PLC backbone network link, and a hybrid path using both a wireless backbone link and a PLC backbone link for forwarding; the total path cost and the path stability of each candidate path are calculated respectively, the total path cost is obtained by weighted accumulation according to the transmission delay and energy consumption indicators of each hop in the path, and only the backbone transmission segment cost except the first and last hops of the source node accessing the backbone network and the destination node leaving the backbone network is counted;

[0030] The path stability is calculated according to the time variance of the link quality index (LQI) of each link through which the path passes; the total path cost and the path instability, i.e., 1 minus the path stability, of the three candidate path schemes are taken as double-target evaluation indexes, and a closeness degree analysis method is introduced to comprehensively evaluate the candidate paths; the total path cost and the path instability of the candidate paths are taken as the performance index space of a two-dimensional coordinate system, an imaginary ideal scheme with the lowest total cost and the lowest instability is recorded as an ideal solution, and an imaginary scheme with the highest total cost and the highest instability is recorded as a worst solution; the Euclidean distance between each candidate path and the ideal solution and the worst solution is calculated, and the distance size is used to measure the performance closeness degree of the candidate path; the closeness degree values of the candidate paths are compared, and the greater the closeness degree value is, the better the comprehensive performance of the path scheme is; and the path with the greatest closeness degree is selected from the three candidate paths as the actual communication path between the source node and the destination node.

[0031] The technical effect and advantages of the multi-path communication guarantee system of the power Internet of Things terminal are as follows:

[0032] The system can flexibly select wireless or PLC communication technology by dynamically evaluating the quality and energy consumption efficiency of each link, and avoids the communication performance bottleneck that may be caused by excessive dependence on a certain technology. The minimum spanning tree algorithm is respectively run for the wireless and PLC link networks, which can effectively construct an optimized backbone structure in the respective networks and improve the resource utilization rate and network performance of each subnetwork. The detection and completion of the distorted node pairs in the network can effectively repair the network instability caused by link quality fluctuations and network topology changes. The cost and stability of pure wireless paths, pure PLC paths and mixed paths are calculated, which can select the most suitable path between the source node and the destination node, thereby improving the reliability of the network and optimizing the communication efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The figure is a structural schematic diagram of the multi-path communication guarantee system of the power Internet of Things terminal.

[0034] Figure 2 The figure is a flowchart of the link set construction of the mixed topology construction module.

[0035] Figure 3 The figure is a flowchart of the construction of the backbone network prototype and the completion of the communication backbone tree through distortion edge completion. DETAILED DESCRIPTION

[0036] With reference to the accompanying drawings: the technical solutions in the embodiments of the present application will be clearly and completely described, obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0037] Embodiments

[0038] The application discloses a kind of power internet of things terminal's multi-path communication guarantee system, comprising: hybrid topology construction module, backbone sketch generation module, distortion edge filling module and optimal path selection module, signal connection between each module.

[0039] Hybrid topology construction module: construct the network topology structure of wireless+PLC fusion, the advantage of wireless communication and PLC communication is selected according to the link quality index and energy consumption-bandwidth ratio of each link Corresponding communication technology, link is divided into wireless link, PLC link and dual stack link, and node link upper limit constraint is applied to construct the link set of wireless and PLC respectively;

[0040] It should be noted that PLC is power line communication (Power Line Communication). It refers to the communication technology for data transmission using power line as communication medium, and the application is combined with wireless communication technology to construct fusion topology for the communication link of power internet of things terminal.

[0041] Backbone sketch generation module: wireless communication and PLC communication link subnet are extracted respectively, different weights are set, MST is used to run minimum spanning tree algorithm on respective subnet, and the backbone network sketch of wireless communication and PLC communication is generated respectively;

[0042] It should be noted that MST is minimum spanning tree (Minimum Spanning Tree). It is a graph theory algorithm, and the application is used to select backbone transmission link in the initial topology of wireless subnet and PLC subnet, generate the backbone network sketch covering all nodes and having minimum total weight, to optimize the performance of subnet.

[0043] Distortion edge filling module: traverse the node pair of the backbone network sketch of wireless communication and PLC communication, detect the distortion node pair in the backbone network sketch, select "single-source batch" or "global revenue sorting" completion strategy combining link quality fluctuation and distortion pair density, generate complete wireless communication and PLC communication backbone tree;

[0044] Optimal path selection module: calculate the total path cost and path stability of pure wireless path, pure PLC path and hybrid path from source node to destination node, and select the optimal multi-hop communication path by closeness analysis method.

[0045] In the mixed topology construction module, the wireless+PLC fusion network topology structure is constructed, the advantage points of wireless communication and PLC communication are calculated respectively according to the link quality index and energy-bandwidth ratio of each link, the corresponding communication technology is selected, the link is divided into wireless link, PLC link and dual stack link, and the node link upper limit constraint is applied to construct the wireless and PLC link set respectively, and the specific content includes:

[0046] The power internet of things terminal is recorded as a node, for n nodes, any node pair The one-hop communication path that can be established between the nodes is recorded as a link The links are connected to form a network, and each link in the network is filtered through a threshold, and the filtered link set forms an initial topology structure:

[0047] All nodes in the network have wireless and PLC dual communication interfaces, i.e. dual stack capability, and the nodes that can be connected through distance filtering are set, and all node pairs The links are filtered through wireless and PLC thresholds respectively:

[0048] Wireless threshold filtering rule: geometric distance ≤ preset maximum feasible distance ;

[0049] PLC threshold filtering rule: the length of the same phase line must be ≤ the line feasible upper limit ;

[0050] For the filtered node pair , if only one threshold filtering rule is passed, the link is locked as the corresponding link type, and for the link passing two threshold filtering rules, the advantage points of wireless communication and PLC communication are calculated, and the corresponding communication technology is selected to divide the link into wireless link, PLC link and dual stack link:

[0051] Link index assignment: randomly assign a link quality index and an energy-bandwidth ratio to each potential link, obtain the bidirectional LQI of the node pair and take the smaller value, if only a one-way LQI is obtained, directly use the value; obtain the EBR value of the node pair ; wherein, the higher the LQI value, the better the wireless signal and the higher the reliability of the link; EBR represents the energy consumed for unit bandwidth transmission, and the lower the value, the more energy-efficient the link transmission is;

[0052] Compare the advantage points of the same node pair under two communication modes, and calculate the link : ; wherein, , are the advantage points of wireless communication and PLC communication respectively, Figure 2Swand Spdenote the simplified values of S and S, respectively;

[0053] Link type classification: according to the advantage score of wireless communication and PLC communication Classify each link:

[0054] Unusable link: if = 0 and = 0, indicating that neither wireless nor PLC can establish reliable communication, the link is discarded and not included in the topology;

[0055] Wireless preferred link: if , it means that the advantage of this link under wireless communication is much greater than that under PLC communication, so this link is confirmed as a wireless link, that is, subsequent communication prefers the wireless channel;

[0056] PLC preferred link: if , it means that this link has more advantages under PLC communication, so it is confirmed as a PLC link, which prefers the power line channel;

[0057] Dual stack link: otherwise, that is, the difference between the two is not more than a times, it is considered that the performance of wireless and PLC is similar, so this link is marked as a dual stack link, indicating that the link can support both wireless and PLC, and the two communication modes can be dynamically switched or used in parallel in redundancy;

[0058] It should be noted that a is used to measure the significant difference threshold of the advantage score of wireless communication and PLC communication, both of which are derived from the comprehensive scoring system of the link quality index LQI and the energy-bandwidth ratio EBR of the link. Based on the significance discrimination of measurement and estimation error and scene fluctuation in the calculation of the advantage score, mainly referring to the influence of LQI measurement noise, EBR estimation error and on-site electromagnetic and load fluctuation on the stability of the score, the minimum multiple is taken to make the probability of misjudgment within the acceptable range of engineering, and the initial setting of a is 1.5 by engineering default, and the recommended range is 1.3-1.7. The specific setting can be made by the person skilled in the art according to the actual situation.

[0059] In order to prevent a single node from connecting too many neighbors, resulting in excessive overhead or increased interference, an upper limit value is set for the number of links of each node. After the classification of candidate links, for wireless links and dual stack links, the highest advantage score of a certain number of wireless links for each node is retained; similarly, for PLC links and dual stack links, the highest advantage of a certain number of PLC links for each node is retained.

[0060] By pruning edges that exceed the degree upper limit, two sub-topologies are finally obtained: one is a wireless link set containing all selected wireless links, and the other is a PLC link set containing all selected PLC links. These two link sets respectively constitute the initial topology structure of the wireless subnetwork and the PLC subnetwork.

[0061] In the backbone sketch generation module, the wireless communication and PLC communication link subnets are extracted respectively, different weights are set, the MST is used to run the minimum spanning tree algorithm on each subnet, and the wireless communication and PLC communication backbone network sketches are generated respectively. The specific content includes:

[0062] On the obtained wireless subnet and PLC subnet, the minimum spanning tree algorithm is used to extract the respective backbone network sketches of the two communication modes, ensuring that the total link cost is minimized while maintaining connectivity of all nodes.

[0063] Set the weight criterion: according to the characteristics of different communication media, set different weight calculation methods for wireless links and PLC links, and the weight represents the "cost" index that needs to be minimized in the minimum spanning tree algorithm. For wireless networks, focus on reducing transmission energy consumption and reducing interference, and select the energy consumption or delay of wireless links as the weight; for PLC networks, more attention is paid to channel stability or delay, and the weight is set according to the noise level or reliability of PLC links. Reasonable weight design can make the generated MST backbone optimize the main performance indicators of each network respectively.

[0064] Generate the backbone network sketch of PLC communication: apply Kruskal algorithm on the wireless subnet to select the edge set with the set weight, the algorithm starts with the wireless link with the smallest weight and gradually adds, avoiding loops, until all nodes are connected. The resulting wireless MST is a tree structure that covers all nodes in the network, and has the property of minimum total weight under wireless links, which is the backbone network sketch for wireless communication.

[0065] Generate the backbone network sketch of PLC communication: similarly, execute the MST algorithm on the PLC subnet using a different weight criterion than wireless, and obtain the PLC MST backbone, which also contains all nodes and minimizes the total cost of PLC links. This PLC spanning tree serves as the backbone network sketch for PLC communication.

[0066] In the distortion edge completion module, the backbone network sketch nodes of wireless communication and PLC communication are traversed, the distorted node pairs in the backbone network sketch are detected, the "single-source batch" or "global revenue sorting" completion strategy is selected according to the link quality fluctuations and distortion pair density, and the complete wireless communication and PLC communication backbone tree is generated. The specific content includes:

[0067] Distortion rule definition: define a distortion criterion to measure the degree of deviation of the backbone network sketch path. Set the multi-hop communication path cost between two nodes in the wireless and PLC backbone network sketch structure as ; the shortest path cost between nodes i and j is ;

[0068] If for a pair of nodes , wherein ; wherein is a distortion threshold coefficient, it is said that the node pair produces "distortion" in the current backbone network sketch, and the node pair determined to be distorted is denoted as a "distortion pair". The distortion pair means that under the current backbone network sketch, the communication of the two nodes is obviously detoured, and there is a significant optimization space. By identifying all distortion pairs, the weak links that need to be focused on optimizing in the backbone network are found.

[0069] Distortion analysis: all nodes in the backbone network sketch structure of wireless communication and PLC communication are traversed, the number of distortion pairs is counted as the distortion degree of the node, the average value of the distortion degrees of all nodes is calculated, and the standard deviation is calculated to measure the overall fluctuation. Nodes with distortion degrees higher than the average value of the distortion degrees plus the standard deviation are grouped into a set C, and the Gini coefficient is calculated in combination with the difference in the distortion degrees of all nodes.

[0070] It should be noted that Gini is the Gini coefficient (Gini Coefficient). The present application is used to calculate in combination with the difference in the distortion degrees of all nodes, quantify the unevenness of the distribution of the distortion degrees of the nodes, and serve as one of the bases for selecting the "single-source batch edge supplement" or "global revenue ranking edge supplement" strategy.

[0071] When and only when the number of nodes in set C does not exceed the preset percentage of the total number of network nodes and when the Gini coefficient is greater than the preset coefficient threshold, for each central node in set C, the single-source batch edge supplement is adopted: a number of direct edges are supplemented to the node at one time to simultaneously solve the detour problem of the node and multiple neighbors; otherwise, the whole distortion gap is considered to be in a scattered or global state, and the global revenue ranking edge supplement is adopted: all candidate links are sorted according to the revenue of the path improvement of the whole network, and are sequentially added to the backbone, and the revenue is updated while the edges are added, until the distortion pair is eliminated or the edge supplement upper limit is reached.

[0072] Candidate edge supplement set: in order to eliminate distortion, additional links need to be added in the backbone network sketch. The candidate edges for selection are usually derived from those links in the original topology that are not adopted by the MST: that is, the links in the wireless or PLC subnets that are not in the backbone network sketch. Each candidate edge connects two nodes that can currently reach each other through multiple hops in the backbone network sketch, and the direct addition of the edge will form a loop to provide a new shorter path for these nodes. Therefore, the candidate edge is a direct means to improve the communication path. Next, it is necessary to determine which edge supplement strategy will be used to add these candidate edges to the backbone.

[0073] Edge supplement strategy design: the present application proposes two edge supplement selection strategies, which can be selected according to the distortion distribution characteristics for optimization:

[0074] Strategy one, single-source batch addition:

[0075] Batch adding links in multiple directions from each center node in set C, and add some direct edges in the original topology that are not in the backbone network prototype to the backbone. Preferably, the edges that significantly shorten the distance between the center node and other nodes are added. If node X communicates with many nodes by going far, then the candidate links that directly connect X to these nodes or intermediate nodes are added one by one. By adding multiple edges to the center node in one operation, the communication cost between the node and multiple regions can be reduced, and multiple distortion pairs can be eliminated at the same time. This strategy is suitable for the case where distortion pairs are mainly caused by insufficient connection of individual hub nodes. Once the connection of the node is strengthened, the overall performance can be greatly improved.

[0076] Strategy two, adding according to global revenue ranking:

[0077] All candidate edges are evaluated, the revenue value of each edge on the current backbone is calculated, and the edges are ranked from high to low according to the revenue. Then the edge with the highest revenue is selected and added. After adding an edge, the backbone network prototype is updated and the revenue of the remaining candidate edges can be re-evaluated, and the next one is selected. This process continues until there is no distortion pair or the predetermined optimization degree is reached. The global ranking strategy can ensure that each addition maximally reduces the average path cost of the entire network, and is suitable for complex distortion pair causes and fine optimization scenarios. The disadvantage is that the calculation and iteration process is relatively complex, but the result often makes the backbone network close to optimal.

[0078] Perform edge addition and backbone completion: according to the above two strategies, one of them is selected to add edges to the backbone network prototype of the wireless network and the PLC network. For the wireless backbone, a single source batch or global ranking can be used according to the actual situation. After selecting the strategy, a number of links are selected from the wireless candidate edge set according to the strategy rules and added to the wireless backbone network. Similarly, the PLC backbone network is also processed accordingly. During the edge addition process, the number of links of each node should not exceed the limit. If the strategy requires the addition of an edge that will exceed the limit of the number of node connections, the edge should be skipped or replaced with a suboptimal edge. After the edge addition is completed, the wireless and PLC backbones change from the original tree structure to an enhanced backbone network containing a small amount of redundant loops. At this time, the backbone network is more complete, and there are usually multiple connected paths between each pair of nodes, greatly reducing the degree of path detouring. By designing appropriate number and position of edges, the backbone network can meet the predetermined distortion constraint, i.e. the communication path cost between any two nodes does not exceed times of the global shortest path.

[0079] After the edge addition operation is performed, the complete wireless communication and PLC communication backbone tree is generated.

[0080] In the optimal path selection module, the total path cost and path stability of the pure wireless path, the pure PLC path and the mixed path from the source node to the destination node are calculated, and the optimal multi-hop communication path is selected by closeness analysis method, and the specific content includes:

[0081] After the perfect wireless communication and PLC communication backbone tree is constructed, specific multi-hop transmission paths are selected for the communication node pairs needed in the network. For any given source node and destination node, this module considers three types of candidate path schemes: the first is a pure wireless path composed of wireless backbone tree links, the second is a pure PLC path composed of PLC backbone tree links, and the third is a mixed path using both wireless and PLC backbone tree links. For each path, the total path cost and path stability are calculated and compared, and only the cost of the intermediate backbone tree segment, i.e. the first and last hop cost of the source node accessing the backbone tree and the destination node leaving the backbone tree, is counted, which is the same in each scheme. According to the specific requirements, the evaluation index is selected.

[0082] For any node pair , an algorithm is designed to calculate the multi-hop routing from i to j in the wireless backbone graph and the PLC backbone graph respectively, and the total path cost is calculated:

[0083] The path stability is calculated from the time variance of each link LQI.

[0084] It should be noted that LQI is the Link Quality Index. It is used to evaluate the communication quality of the link. The smaller value of the bidirectional LQI of the link is taken as the evaluation value, which is an important parameter for calculating the wireless and PLC communication advantage score and the path stability (based on time variance).

[0085] Taking the lowest path cost and the highest path stability as the optimization goal, the closeness analysis method is used to select the best comprehensive performance from the three types of candidate paths, as the actual use path of the communication node pair: the total path cost and path instability of the three types of candidate paths, i.e. one minus the path stability, are regarded as two-dimensional indicators, and the Euclidean distance between them and the ideal solution and the worst solution is calculated to quantify the "closeness" of each path to the ideal path, which is recorded as closeness, the ideal solution is when the total path cost and path instability are both the lowest, and the worst solution is when the total path cost and path instability are both the highest.

[0086] The larger the closeness value is, the better the comprehensive performance of the path is, and the path with the largest closeness value is finally selected as the actual communication path.

[0087] It should be noted that the closeness analysis method is a path selection strategy without subjective weight, which is used to measure the total cost and path stability in the candidate path. The method is suitable for the scene where the path performance is significantly affected by the dynamic environment and it is difficult to set clear preferences. The method can achieve automatic balance in the geometric sense between cost and stability, and ensure that the power internet terminal selects the most reasonable multi-hop communication scheme in the three types of paths.

[0088] The above formulas are dimensionless values calculated, and the formulas are obtained by collecting a large amount of data to simulate the most recent real situation. The preset parameters in the formula are set by a person skilled in the art according to the actual situation.

[0089] The above embodiments can be realized wholly or partially by software, hardware, firmware or any combination thereof. When realized by software, the above embodiments can be realized wholly or partially in the form of a computer program product.

[0090] Those skilled in the art can realize that the modules and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application of the technical solution and the constraints of the application. Professional technicians can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0091] In addition, each functional module in each embodiment of the present application can be integrated in one processing module, or each module can exist physically alone, or two or more modules can be integrated in one module.

[0092] The above is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any skilled person in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0093] Finally, the above is only the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1.A multi-path communication guarantee system of a power internet of things terminal, characterized by, The application relates to a multi-hop communication path selection method based on a wireless and PLC integrated network topology, which comprises the following modules: a mixed topology construction module, a backbone sketch generation module, a distortion edge supplement module and an optimal path selection module. The mixed topology construction module: constructs a wireless and PLC integrated network topology structure, calculates the advantages of wireless communication and PLC communication according to link quality indexes and energy consumption-bandwidth ratios of respective links, selects corresponding communication technologies, divides the links into wireless links, PLC links and double-stack links, and applies node link upper limit constraints to construct wireless and PLC link sets respectively; The backbone sketch generation module: extracts wireless communication and PLC communication link subnets respectively, sets different weights, uses MST to run a minimum spanning tree algorithm on the respective subnets, and generates wireless communication and PLC communication backbone network sketches respectively; The distortion edge supplement module: traverses wireless communication and PLC communication backbone network sketch node pairs, detects distortion node pairs in the backbone network sketches, selects a "single-source batch" or "global revenue sorting" supplement strategy according to link quality fluctuations and distortion pair densities, and generates complete wireless communication and PLC communication backbone trees; The optimal path selection module: calculates total path costs and path stability degrees of pure wireless paths, pure PLC paths and mixed paths from a source node to a destination node, and selects an optimal multi-hop communication path through a closeness analysis method; The single-source batch edge supplement is adopted only when the number of nodes in the set C does not exceed a preset percentage of the total number of network nodes and when the Gini coefficient is greater than a preset coefficient threshold; The distortion edge supplementing module is used for detecting and quantifying the communication path distortion condition in the wireless communication backbone network prototype and the PLC communication backbone network prototype, and specifically comprises: for any two nodes i and j in the backbone network prototype, the multi-hop communication path cost between the two nodes is ; the shortest path cost between the two nodes i and j is , if there is ; wherein γ is a preset distortion threshold coefficient, it is determined that the node pair produces communication distortion under the current backbone network prototype, and all node pairs satisfying the condition are recorded as distortion pairs; all nodes in the backbone network prototype are traversed, the number of distortion pairs involved by each node as an end point is counted, and is recorded as the distortion degree of the node; the average value and the standard deviation of all node distortion degrees are calculated, a node set with a distortion degree higher than the sum of the average value and the standard deviation and with a corresponding node accounting for no more than a preset proportion of the total number of nodes is recorded as a high distortion center node set C; and the Gini coefficient is calculated in combination with the difference of all node distortion degrees. For each central node in the set C, a number of direct edges are supplemented to the node at one time to simultaneously solve the detour problem of the node and multiple neighbors; The global revenue sorting edge supplement is adopted in other cases, that is, the overall distortion gap is considered to be scattered; All candidate links are sorted according to their path improvement revenues of the whole network, and are sequentially added to the backbone, and the revenue is updated while the edges are added, until the distortion pairs are eliminated or the edge supplement upper limit is reached; The complete wireless communication and PLC communication backbone trees are generated by using the "single-source batch" or "global revenue sorting" supplement strategy; The optimal path selection module provides multi-hop communication path selection for any given source node and destination node after obtaining perfect wireless communication backbone networks and PLC communication backbone networks, and the multi-hop communication path selection specifically includes: a pure wireless path which is forwarded only through wireless backbone network links, a pure PLC path which is forwarded only through PLC backbone network links, and a mixed path which utilizes wireless backbone links and PLC backbone links simultaneously; total path costs and path stability degrees of each candidate path are calculated, the total path cost is obtained by weighting and accumulating transmission time delays and energy consumption indexes of each hop in the path, and only the backbone transmission section cost except the first and last hops of the source node and the destination node accessing and leaving the backbone network is counted; the path stability degree is calculated according to time variances of link quality indexes LQI of links in the path; the total path cost and the path instability degree, that is, 1 minus the path stability degree, of the three candidate path schemes are used as double-target evaluation indexes, and a closeness analysis method is introduced to comprehensively evaluate the candidate paths. ​ ​ The closeness analysis method quantifies the path synthesis performance by calculating the Euclidean distance of the candidate path relative to the ideal solution and the worst solution, and selects the path with the largest closeness value as the final communication scheme, specifically including: the total path cost and path instability of the candidate path constitute the performance index space of the two-dimensional coordinate system, the imaginary ideal solution with the lowest total cost and the lowest instability is recorded as the ideal solution, and the imaginary solution with the highest total cost and the highest instability is recorded as the worst solution; calculate the Euclidean distance between each candidate path and the ideal solution and the worst solution, and measure the performance closeness of the candidate path according to the distance size; compare the closeness values of each candidate path, the larger the closeness value, the better the comprehensive performance of the path scheme, and select the path with the largest closeness from the three candidate paths as the actual communication path between the source node and the destination node. 2.The multi-path communication guarantee system of a power internet of things terminal according to claim 1, wherein, The hybrid topology construction module constructs the initial network topology of the wireless+PLC fusion of the power Internet of Things terminal node through the following steps: two nodes of the power Internet of Things terminal are combined to form a potential one-hop communication link, and the feasibility of all potential links is screened according to the preset conditions; when the geometric distance between the two nodes is less than or equal to the preset maximum wireless communication distance, it is determined that the wireless communication of the link is feasible, and when the length of the in-phase power line between the two nodes is less than or equal to the preset upper limit of the line feasibility, it is determined that the PLC communication of the link is feasible; the screened links are preliminarily classified according to the medium feasibility: the link that only meets the wireless communication feasibility condition is marked as a wireless link, the link that only meets the PLC communication feasibility condition is marked as a PLC link, and the link that meets the wireless and PLC communication feasibility conditions is marked as a dual available link. 3.The multi-path communication guarantee system of a power internet of things terminal according to claim 2, wherein, The hybrid topology construction module determines the link type by calculating the communication advantage score of the link that meets the wireless and PLC feasibility conditions, including: obtaining the link quality index LQI and the energy-bandwidth ratio EBR parameter of each potential link that meets the wireless and PLC communication conditions, taking the smaller value of the bidirectional LQI value of the link as the LQI evaluation value of the link, and obtaining the EBR evaluation value of the link; based on the LQI evaluation value and the EBR evaluation value, the advantage score of the link in the wireless communication mode and the PLC communication mode is calculated; compare the wireless communication advantage score and the PLC communication advantage score, and determine the link type according to the predetermined criterion: If the wireless communication advantage score and the PLC communication advantage score are both 0, it is determined that the link cannot establish reliable communication under the two media, the link is discarded and not included in the network topology; If the wireless communication advantage score is greater than the preset multiple threshold of the PLC communication advantage score, the link is determined as a wireless link, and subsequent communication is preferentially transmitted through the wireless channel; if the PLC communication advantage score is greater than the preset multiple threshold of the wireless communication advantage score, the link is determined as a PLC link, and subsequent communication is preferentially transmitted through the power line channel; Otherwise, when the difference between the two communication mode advantages does not exceed the preset multiple threshold, it is determined that the wireless and PLC performance of the link is similar, the link is marked as a dual stack link, and the link can support dynamic switching or parallel redundant use of the wireless and PLC communication modes. 4.The multi-path communication guarantee system of a power internet of things terminal according to claim 3, wherein, The mixed topology construction module applies a node link quantity upper limit constraint to the network topology obtained through link classification to control the connection degree of each node, and specifically includes: setting a wireless link connection quantity upper limit value and a PLC link connection quantity upper limit value for each node respectively, for limiting the maximum link quantity of a single node in the wireless communication and PLC communication modes; for the wireless link and dual stack link set, sorting the available wireless directional links of each node according to the high-low of the wireless communication advantage score, and preferentially reserving a plurality of wireless links with the highest advantage score, so that the wireless link quantity of each node does not exceed the wireless link upper limit value; For the PLC link and dual stack link set, the available PLC directional links of each node are sorted according to the high-low of the PLC communication advantage score, and a plurality of PLC links with the highest advantage score are preferentially reserved, so that the PLC link quantity of each node does not exceed the PLC link upper limit value; after the links exceeding the upper limit are pruned, the wireless link set and the PLC link set are formed as the wireless subnetwork initial topology and the PLC subnetwork initial topology respectively, and all nodes in the wireless subnetwork initial topology and the PLC subnetwork initial topology satisfy the respective node link quantity upper limit constraint. 5.The multi-path communication guarantee system of a power internet of things terminal according to claim 1, wherein, The backbone sketch generation module respectively executes a minimum spanning tree algorithm on the wireless subnetwork initial topology and the PLC subnetwork initial topology to construct a communication backbone network sketch, and sets a link weight calculation rule for different communication media to optimize the performance of each network, wherein: Different link weight indicators are set according to the differences between the wireless communication and PLC communication media characteristics: for the wireless link, a parameter capable of reflecting transmission energy consumption or transmission delay is selected as the weight; for the PLC link, a parameter capable of reflecting the power line channel noise level or link reliability is selected as the weight; the minimum spanning tree algorithm is applied in the wireless communication and PLC communication subnetwork initial topologies respectively to select the backbone transmission link, and the wireless communication and PLC communication backbone network sketches covering all nodes and having the minimum total wireless link weight are generated.

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