A method for selecting an MPR set based on an analytic hierarchy process (AHP) comprehensive metric of an OLSR routing protocol

Abstract

The application discloses a kind of based on analytic hierarchy process's OLSR routing protocol comprehensive measure MPR set selection method, it is related to wireless communication technology routing protocol field.It includes: by spatial coordinates combination node mobility obtains link duration, joins the consideration to node energy to ensure link stability, the consideration to node coverage to realize more efficient node coverage and connection;The accurate calculation of weight factor of three influence factors is realized using analytic hierarchy process, and finally the selection of MPR node is carried out by the comprehensive measure value obtained.The application is suitable for the selection of MPR node in OLSR routing protocol network under high-speed mobile environment, and the node coverage and routing establishment can be carried out quickly and efficiently by optimizing MPR technology, with the advantages of small communication delay, fast response speed and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wireless communication technology routing protocol, in particular to a kind of OLSR routing protocol comprehensive degree measurement MPR set selection method based on analytic hierarchy process. BACKGROUND

[0002] OLSR protocol is a priori routing protocol, and through MPR (Multi Point Relay) technology, fast and efficient node coverage and routing establishment can be carried out, with small communication delay, fast response speed and other characteristics. Unmanned aerial vehicle group, which plays an increasingly important role in the network, has the characteristics of large number of nodes, fast moving speed, and topology change, which can easily lead to frequent link interruption. Therefore, in this high mobility scenario, it is necessary to ensure link stability, topology connection coverage and network system performance. It has become a crucial research content in large-scale wireless communication field.

[0003] As an important part of large-scale ad hoc network wireless communication system, the topology efficient establishment of routing protocol plays a very key role in improving system performance. In high-speed mobile scenarios, the network topology presents complex and changeable characteristics, and the use of node movement state for communication behavior prediction is an important way to improve link quality in this scenario. Considering the link duration, node energy condition and coverage depth, it is an effective method to realize network topology stable connection. However, in complex scenarios, subjective factor weight distribution cannot meet the network demand. SUMMARY

[0004] Therefore, the present application provides an OLSR routing protocol comprehensive degree measurement MPR set selection method based on analytic hierarchy process. The present application considers node mobility, node energy and node coverage to ensure link state, and uses analytic hierarchy process to realize more efficient and stable network topology connection.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] An OLSR routing protocol comprehensive degree measurement MPR set selection method based on analytic hierarchy process is applied to unmanned aerial vehicle networking communication system, which is used for source node unmanned aerial vehicle to select MPR node set. Each unmanned aerial vehicle node in the unmanned aerial vehicle networking communication system is equipped with GPS and speedometer, and the initial maximum energy of each unmanned aerial vehicle node is E ini ; The method comprises the following steps:

[0007] (1) The source node unmanned aerial vehicle s obtains its one-hop neighbor node set N1 and two-hop neighbor node set N2, and the total number of two-hop neighbor nodes in N2 is Nmax ;

[0008] (2) Source node drone s obtains the coordinates, speed and moving direction of itself and each one-hop neighbor node in three-dimensional space, and calculates the Euclidean distance d sn between source node drone s and one-hop neighbor node n x , horizontal distance d y between nodes, and vertical distance d sn , and further calculates the link duration t sn between source node drone s and one-hop neighbor node n max , the maximum value of t sn is the longest link duration t s , n∈N1;

[0009] (3) Source node drone s obtains the node residual energy of each one-hop neighbor node and counts the number of two-hop neighbor nodes covered by each one-hop neighbor node Then, the residual energy ratio of each one-hop neighbor node is calculated , the link duration ratio is calculated , and the node coverage ratio is calculated

[0010] (4) Based on the analytic hierarchy process, the hierarchical structure of the link duration ratio, the residual energy ratio and the node coverage ratio is established, and the weight values α, β and λ of the link survival time, the residual energy ratio and the node coverage are calculated;

[0011] (5) According to the unique coverage of one-hop neighbor nodes to two-hop neighbor nodes, the corresponding nodes are selected from one-hop neighbor node set N1 and put into MPR node set, and the two-hop neighbor nodes that have been covered in two-hop neighbor node set N2 are removed; Then, in the remaining one-hop neighbor nodes, the node with the maximum comprehensive measurement value M(n) is selected and put into the MPR node set in turn, until the nodes in two-hop neighbor node set N2 are all covered; The calculation method of comprehensive measurement value M(n) is:

[0012]

[0013] Further, in step (2), the calculation method of link duration t sn is:

[0014]

[0015] In the formula, a=v s cos(f s )-v n cos(f n ), b=x s -x n , and c=v ssin(f s )-v n sin(f n ), d = y s -y n , r is the communication range radius of the source node UAV s, f is the node moving direction angle, v is the node moving speed, subscript s represents the source node UAV, and subscript n represents a one-hop neighbor node.

[0016] Further, the specific manner of step 5 is as follows:

[0017] If a two-hop neighbor node can be connected only by a unique one-hop neighbor node, the one-hop neighbor node is directly put into the MPR node set, the one-hop neighbor node is deleted from N1, and all two-hop neighbor nodes connected by the one-hop neighbor node are deleted from N2;

[0018] The remaining one-hop neighbor nodes are sorted in descending order of the comprehensive metric value M(n), and the one-hop neighbor node with the maximum comprehensive metric value is selected and put into the MPR node set, the one-hop neighbor node is deleted from N1, and all two-hop neighbor nodes connected by the one-hop neighbor node are deleted from N2, until all nodes in N2 are deleted, and thus the final MPR node set is obtained.

[0019] Further, the specific manner of step 4 is as follows:

[0020] The selected MPR node is taken as a target layer, the link duration ratio, the residual energy ratio, and the node coverage ratio are taken as decision layers, and the one-hop neighbor nodes in the one-hop neighbor node set N1 are taken as a scheme layer, to obtain a hierarchical structure, and a three-order judgment matrix D is constructed according to the influence degree of the three variable factors in the decision layer on the target layer.

[0021]

[0022] In the matrix D, d ij represents the importance relationship between the variable factor i and the variable factor j, and subscripts 1, 2, and 3 represent the link duration ratio, the residual energy ratio, and the node coverage ratio, respectively. ij The value of d ij is 1, 2, 3, 4, or 5, d ij = 1 indicates that the variable factor i and the variable factor j are equally important, d ij = 5 indicates that the variable factor i is obviously more important than the variable factor j, and other values of d ij = 1 / d ji .

[0023] The maximum eigenvalue λ max of the matrix D is solved, and λ maxThe corresponding eigenvector W, after normalization of W, obtains The elements of the matrix are weight values α, β and λ.

[0024] The beneficial effects of the present application are:

[0025] 1. The present application predicts the node mobility in the spatial coordinate system through various movement state indicators of the node, and ensures that the selected MPR node can have better performance in link sustainability when selecting the MPR node.

[0026] 2. The present application improves the network topology stability establishment compared to single constraint condition by comprehensively considering the link duration, node energy condition and topology coverage.

[0027] 3. The present application uses the analytic hierarchy process to establish a hierarchical structure of multiple influencing factors, and more accurately distributes the weight factors of these factors to obtain a comprehensive measurement value, so as to realize more efficient and accurate MPR node selection and network topology establishment. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a flowchart of the present application.

[0029] Figure 2 is a schematic diagram of node mobility prediction in the present application.

[0030] Figure 3 is a schematic diagram of MPR node coverage in the present application.

[0031] Figure 4 is a hierarchical structure diagram of MPR node selection in the present application. DETAILED DESCRIPTION

[0032] In order to clearly illustrate the technical features of the present application, the present application will be described in detail below with reference to the specific embodiments and in conjunction with the accompanying drawings.

[0033] An OLSR routing protocol comprehensive measurement MPR set selection method based on the analytic hierarchy process is applied to a UAV networking communication system, and is used for source node UAV to select an MPR node set; each UAV node in the UAV networking communication system is provided with a GPS and a speedometer, and the initial maximum energy of each UAV node is E ini ; the method comprises the following steps:

[0034] (1) The source node UAV s obtains its one-hop neighbor node set N1 and two-hop neighbor node set N2, and the total number of two-hop neighbor nodes in N2 is N max ;

[0035] (2) The source node UAV s obtains the coordinates, speed and moving direction of itself and each one-hop neighbor node in three-dimensional space, and calculates the Euclidean distance d between the source node UAV s and the one-hop neighbor node n sn , the horizontal distance d between nodes x , the vertical distance d y , and further calculates the link duration t between the source node UAV s and the one-hop neighbor node n sn , the maximum value of t sn is the longest link duration t max , n∈N1; the calculation method of the link duration t sn is as follows:

[0036]

[0037] In the formula, a=v s cos(f s )-v n cos(f n ), b=x s -x n , c=v s sin(f s )-v n sin(f n ), d=y s -y n , r is the communication range radius of the source node UAV s, f is the node moving direction angle, v is the node moving speed, the subscript s represents the source node UAV, and the subscript n represents the one-hop neighbor node.

[0038] (3) The source node UAV s obtains the node residual energy of each one-hop neighbor node and counts the number of two-hop neighbor nodes covered by each one-hop neighbor node Then, the residual energy ratio , the link duration ratio , and the node coverage ratio of each one-hop neighbor node are calculated.

[0039] (4) Based on the analytic hierarchy process, the hierarchical structure of the link duration ratio, the residual energy ratio and the node coverage ratio is established, and the weight values α, β and λ of the link survival time, the residual energy ratio and the node coverage are calculated; the specific method is as follows:

[0040] The selected MPR node is taken as the target layer, the link duration ratio, the residual energy ratio and the node coverage ratio are taken as the decision layer, and the one-hop neighbor node in the one-hop neighbor node set N1 is taken as the scheme layer, so as to obtain the hierarchical structure, and a three-order judgment matrix D is constructed according to the influence degree of the three variable factors in the decision layer on the target layer:

[0041]

[0042] In matrix D, d ij represents the importance relationship between variable factor i and variable factor j, and subscripts 1, 2, and 3 represent link duration ratio, residual energy ratio, and node coverage ratio respectively, d ij takes values of 1, 2, 3, 4, and 5, d ij = 1 indicates that variable factor i and variable factor j are equally important, d ij = 5 indicates that variable factor i is obviously more important than variable factor j, and d ij other values of d ij = 1 / d ji ;

[0043] Solve the maximum eigenvalue λ max of matrix D, and calculate the eigenvector W corresponding to λ max , and obtain after normalization of W. The elements of W are weight values α, β, and λ.

[0044] (5) According to the unique coverage of one-hop neighbor nodes to two-hop neighbor nodes, corresponding nodes are selected from the one-hop neighbor node set N1 and put into the MPR node set, and the two-hop neighbor nodes that have been covered in the two-hop neighbor node set N2 are removed. Then, in the remaining one-hop neighbor nodes, the node with the maximum comprehensive metric value M(n) is selected and put into the MPR node set in turn, until the nodes in the two-hop neighbor node set N2 are all covered. The calculation method of the comprehensive metric value M(n) is as follows:

[0045]

[0046] The specific method of step 5 is as follows:

[0047] If a two-hop neighbor node can only be connected by a unique one-hop neighbor node, the one-hop neighbor node is directly put into the MPR node set, the one-hop neighbor node is deleted from N1, and all two-hop neighbor nodes connected by the one-hop neighbor node are deleted from N2.

[0048] The remaining one-hop neighbor nodes are sorted in descending order of the comprehensive metric value M(n), and the one-hop neighbor node with the maximum comprehensive metric value is selected and put into the MPR node set in turn, the one-hop neighbor node is deleted from N1, and all two-hop neighbor nodes connected by the one-hop neighbor node are deleted from N2, until all nodes in N2 are deleted. Thus, the final MPR node set is obtained.

[0049] This method obtains link duration by combining spatial coordinates with node mobility, incorporates consideration of node energy to ensure link stability, and considers node coverage to achieve more efficient node coverage and connectivity. Furthermore, it utilizes the analytic hierarchy process (AHP) to accurately calculate the weighting factors of the three influencing factors. Finally, it selects MPR nodes based on the obtained comprehensive metric value, making it suitable for MPR node selection in OLSR routing protocol networks under high-speed mobile environments.

[0050] Here is a more specific example:

[0051] A method for selecting the MPR set of OLSR routing protocol synthesis metrics based on the analytic hierarchy process, such as... Figure 1 As shown, the method includes the following steps:

[0052] (1) Select a Gaussian-Markov (GM) model suitable for UAV node movement scenarios, assuming that each UAV node is equipped with GPS and a speedometer, according to... Figure 2 The central node n shown s One-hop neighbor node n n Coordinates in three-dimensional space (x) i ,y i ), velocity v i , direction of movement f i The Euclidean distance between the two was calculated. After a movement time t, the two nodes undergo corresponding displacements, and the horizontal distance between the two nodes at this time is d. x =x s -x n +[[v s cos(f s )-v n cos(f n )]]t, vertical distance is d y =y s -y n +[[v s sin(f s )-v n sin(f n Based on the above data and considering the limitation of communication distance r in this network, d should be... x 2 +d y 2 <r 2 The mobility of the two nodes is predicted, and the link duration t between the two points is finally calculated. sn for:

[0053]

[0054] In the formula, a = vs cos(f s )-v n cos(f n b = x s -x n c = v s sin(f s )-v n sin(f n ), d=y s -y n ;

[0055] (2) The initial maximum energy of the nodes is the same, which is E. ini The energy consumed to maintain communication and to move are respectively The remaining energy of the node is The total number of bits sent per second by the node is B s The energy consumed to transmit each bit of data per unit distance is E. t If the transmission distance is d, then the remaining energy is The percentage of remaining energy at the nodes can be obtained as follows:

[0056] (3) Based on steps (1) and (2), obtain the link lifetime and remaining energy percentage of the current node, and based on the number of symmetric neighbor nodes, obtain the node coverage of candidate MPR nodes in the traditional MPR set selection algorithm. This yields the criterion layer factors used in the implementation of the analytic hierarchy process (AHP) in this method, where the node coverage of candidate MPR nodes is... For example Figure 3 The node n shown n The number of two-hop neighbor nodes connected to node n n Node coverage The value is 4;

[0057] (4) Based on the analytic hierarchy process, considering link lifetime, node remaining energy, and node coverage, a hierarchical structure is established, and the weight values ​​of the above elements are calculated as α, β, and λ, respectively, to obtain the comprehensive metric value M(n).

[0058] Step (4) is as follows:

[0059] First, the communication distance of one-hop nodes within the MPR candidate set is screened to ensure the feasibility of communication. A hierarchical structure is established based on link lifetime, remaining node energy, and node coverage as criteria. (See the hierarchy diagram below.) Figure 4 The formula for calculating the comprehensive metric value is as follows: Furthermore, a+β+d=1, each being a weighting factor for the corresponding variable factor.

[0060] (5) Construct judgment matrix D based on variable factors:

[0061]

[0062] In the judgment matrix D, d ij This indicates that variable factor i is more important than variable factor j. In this method, it is stipulated that the matrix elements of the two factors are reciprocals of each other, i.e., d ij =1 / d ji Then, calculate the largest eigenvalue λ of the judgment matrix D. max According to λ max The result is the calculation of its corresponding eigenvector W, and the normalization of W yields... The elements in the formula are the moderating weighting factors α, β, and δ for the three variable factors. The formula for calculating the comprehensive metric is as follows: In the formula t max For the maximum communication link duration, The initial maximum energy of the node, N max The total number of two-hop neighbor nodes is used to normalize the variable factors through the above data, and combined with the adjustment of weighting factors α, β, δ, the final comprehensive metric value M(n) is obtained. The larger this value is, the higher the probability that the node will be selected as an MPR node.

[0063] (6) Based on the unique coverage of the one-hop neighbor node set N1 to the two-hop neighbor node set N2, the corresponding nodes are selected and placed into the MPR determination set, and the two-hop neighbor nodes that have been covered in the set N2 are removed. In the remaining one-hop neighbor node set N1, nodes are selected and placed into the MPR determination set according to the comprehensive metric value M(n) until all nodes in the two-hop neighbor node set N2 are covered.

[0064] Step (6) specifically involves:

[0065] (601) Initialize an MPR node set M, and put the nodes in the communication range r of the one-hop neighbor nodes of the central node into the node set M;

[0066] (602) Select the node that uniquely covers the nodes in the two-hop neighbor set N2 within set M, directly determine it as the MPR node, and add it to the MPR node determination set M. R middle;

[0067] (603) Calculate the comprehensive metric value M(n) for the remaining one-hop neighbor nodes in set M. Based on the value of M(n), sequentially select nodes in set M to connect and cover the two-hop neighbor nodes until all two-hop neighbor nodes are covered. Then the MPR node determination set M is determined. R Selection complete.

[0068] The application obtains link duration by combining node mobility with space coordinates, considers node energy to ensure link stability, and considers node coverage to realize more efficient node coverage and connection; the weight factors of the three influence factors are accurately calculated by using analytic hierarchy process, and finally the MPR nodes are selected by the obtained comprehensive measurement value. The application is suitable for MPR node selection in OLSR routing protocol network in high-speed mobile environment, and can realize fast and efficient node coverage and routing establishment by optimizing MPR technology, and has the advantages of small communication delay, fast response speed and the like.

Claims

1. A method for selecting the MPR set of OLSR routing protocols based on the analytic hierarchy process (AHP), applied to an unmanned aerial vehicle (UAV) network communication system, for the source node UAV to select the MPR node set; each UAV node in the UAV network communication system is equipped with GPS and a speedometer, and the initial maximum energy of each UAV node is [missing information]. Its characteristics are, Includes the following steps: (1) The source node drone s obtains its own set of one-hop neighbor nodes. and the set of two-hop neighbor nodes , The total number of two-hop neighbor nodes is ; (2) The source node UAV s obtains its own coordinates, velocity and direction of movement in three-dimensional space as well as each one-hop neighbor node, and calculates the Euclidean distance between the source node UAV s and the one-hop neighbor node n. Horizontal distance between nodes Vertical distance Then, the link duration between the source node drone s and its one-hop neighbor node n is calculated. , The maximum value is the longest link duration. , n∈ ; (3) The source node drone s obtains the remaining node energy of each one-hop neighbor node. And count the number of two-hop neighbor nodes covered by each one-hop neighbor node. ; Then, calculate the ratio of remaining energy of each one-hop neighbor node. Link duration ratio Node coverage ratio ; (4) Based on the analytic hierarchy process, establish a hierarchical structure of link duration ratio, remaining energy ratio, and node coverage ratio, and calculate the weight values ​​of link lifetime, remaining energy ratio, and node coverage. , , The specific method is as follows: The MPR node will be selected as the target layer, and the link duration ratio, remaining energy ratio, and node coverage ratio will be used as the decision layer, along with the set of one-hop neighbor nodes. The one-hop neighbor nodes in the algorithm are used as the solution layer to obtain the hierarchical structure. A third-order judgment matrix is ​​constructed based on the influence of the three variables in the decision layer on the target layer. : ， matrix middle, Indicates variable factors and variable factors The importance relationships are as follows: subscripts 1, 2, and 3 represent the link duration ratio, remaining energy ratio, and node coverage ratio, respectively. The values ​​are 1, 2, 3, 4, and 5. =1 indicates variable factors With variable factors Equally important =5 indicates variable factors Comparison of variable factors Obviously important, Other values ​​represent intermediate states. ; Solve the matrix Maximum eigenvalue and calculate Corresponding feature vector ,right After normalization, we get , The element is the weight value. , , ; (5) Based on the unique coverage of one-hop neighbor nodes to two-hop neighbor nodes, from the set of one-hop neighbor nodes Select the appropriate nodes and add them to the MPR node set, and remove the two-hop neighbor nodes from the set. First, select the two-hop neighbor nodes that have already been covered; then, among the remaining one-hop neighbor nodes, select the comprehensive metric in sequence. The largest node is added to the MPR node set, and so on up to the set of two-hop neighbor nodes. All nodes within are covered; comprehensive metric The calculation method is as follows: 。 2. The method for selecting the MPR set of OLSR routing protocol synthesis metrics based on the analytic hierarchy process according to claim 1, characterized in that, In step (2), the link duration The calculation method is as follows: In the formula, , , , r is the communication range radius of the source node UAV s. The angle representing the direction of node movement. The value represents the node's movement speed. The subscript s indicates the source node (drone) and the subscript n indicates a one-hop neighbor node.

3. The method for selecting the MPR set of OLSR routing protocol synthesis metrics based on the analytic hierarchy process according to claim 1, characterized in that, The specific method for step 5 is as follows: If a two-hop neighbor node can only be connected to one one-hop neighbor node, then that one-hop neighbor node is directly added to the MPR node set, and the one-hop neighbor node is removed from... Remove it, and remove all two-hop neighbor nodes connected to that one-hop neighbor node from... Delete; The remaining one-hop neighbor nodes are sorted according to the comprehensive metric value. Sort the nodes in descending order of their comprehensive metric value, and then add the one-hop neighbor node with the highest comprehensive metric value to the MPR node set. Then, remove the one-hop neighbor node from... Remove it, and remove all two-hop neighbor nodes connected to that one-hop neighbor node from... Deleted until All nodes in the list are deleted, and the final MPR node set is obtained.

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