CN111601351B

CN111601351B - Gateway node selection method, node, device and medium

Info

Publication number: CN111601351B
Application number: CN201910125655.4A
Authority: CN
Inventors: 王峰; 刘刚
Original assignee: Datang Mobile Communications Equipment Co Ltd
Current assignee: Datang Mobile Communications Equipment Co Ltd
Priority date: 2019-02-20
Filing date: 2019-02-20
Publication date: 2022-11-11
Anticipated expiration: 2039-02-20
Also published as: CN111601351A

Abstract

The invention discloses a gateway node selection method, a node, a device and a medium, comprising the following steps: the cluster head DS node acquires local information through neighbor monitoring information and constructs a local 3-hop topology, wherein the DS node is a DS node selected by a cluster head selection algorithm in a self-organizing network, and other nodes are 1-hop neighbors of 1 or more cluster head nodes; after selecting a gateway CS node for a strict 2-hop DS neighbor according to connection information, the DS node selects a CS node for a strict 3-hop DS neighbor, wherein the strict 2-hop DS neighbor of the node refers to the DS node with the shortest communication distance of 2 hops away from the node, and the strict 3-hop DS neighbor of the node refers to the DS node with the shortest communication distance of 3 hops away from the node; and the DS node and the CS node form a connected dominating set. By adopting the invention, the number of redundant gateway nodes can be reduced.

Description

Gateway node selection method, node, device and medium

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a gateway node selection method, a node, an apparatus, and a medium.

Background

The layering of the mobile ad hoc network is an important way for solving the problem of scalability, the clustering is one of important means for realizing the layering of the mobile ad hoc network, and the efficiency of a clustering algorithm directly influences the performance of a mobile ad hoc network application system. In addition, the cluster structure formed by clustering can provide various services for network management. At present, researchers usually study clustering technologies by means of relevant theories of graph theory, improve clustering algorithms and optimize hierarchical structures of mobile ad hoc networks.

In the plane structure, all nodes have equal positions, so the plane structure can be called as a peer-to-peer structure; in the hierarchical structure, the network is divided into clusters, each cluster consists of a cluster head and a plurality of cluster members, the cluster heads form a higher-level network, and the network can be clustered in the higher-level network. In a clustered network, inter-cluster communication is accomplished by means of gateway nodes.

The basic idea of the existing gateway selection algorithm is as follows: the non-cluster head node judges whether the non-cluster head node can receive signals of a plurality of clusters or not by receiving data, and if the non-cluster head node can receive the signals of the plurality of clusters, the non-cluster head node is used as a gateway candidate node; and mutually coordinating a plurality of candidate nodes through a certain rule to determine the gateway.

The existing gateway selection algorithm or the existing connection domination set algorithm utilizes local area information of candidate nodes to carry out election of a gateway or a connection set, the gateway generated by election is often not optimal, and more redundant gateways are generated.

Disclosure of Invention

The invention provides a gateway node selection method, a node, a device and a medium, which are used for reducing redundant gateways.

The embodiment of the invention provides a gateway node selection method, which comprises the following steps:

the cluster head DS node acquires local information through neighbor monitoring information and constructs a local 3-hop topology, wherein the DS node is a DS node selected by a cluster head selection algorithm in a self-organizing network, and other nodes are 1-hop neighbors of 1 or more cluster head nodes;

after selecting a gateway CS node for a strict 2-hop DS neighbor according to connection information, the DS node selects a CS node for a strict 3-hop DS neighbor, wherein the strict 2-hop DS neighbor of the node refers to the DS node with the shortest communication distance of 2 hops away from the node, and the strict 3-hop DS neighbor of the node refers to the DS node with the shortest communication distance of 3 hops away from the node;

and the DS node and the CS node form a connected dominating set.

In the implementation, after the gateway CS node is selected for the strict 2-hop DS neighbor according to the connection information, the CS node is selected for the strict 3-hop DS neighbor according to an A-CS algorithm.

In implementation, according to an A-CS algorithm, a gateway CS node is selected for a strict 2-hop DS neighbor according to connection information, and the selection is performed according to the following rules:

DS node i reaches DS node m through relay node j, if (1) is satisfied

Are all common nodes, (2)i)<m、③m∈H ⁽²⁾ (i) And (4)i to j no 3-hop virtual backbone link exists, then it will be

Joining DS node i to DS nodem's set of candidate CS nodes CS' _im And counting the candidate nodes in the set CS' = ∑ Σ _m CS′ _im ,m>i,m∈H ⁽²⁾ (i) Wherein, the common node is a node except for a DS node and a CS node in the network, and the virtual backbone network link is a transmission link formed by the DS node and/or the CS node;

for the

Node i from set CS of candidate CS nodes' _im Electing the node o with the largest occurrence frequency in the set CS' as a CS node; if the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as a CS node; and if the connectivity is the same, electing the node with the minimum ID as the CS node.

In implementation, according to an A-CS algorithm, a CS node is selected for a strict 3-hop DS neighbor node, and the selection is carried out according to the following rules:

DS node i reaches DS node r through relay nodes j and m, if (1) is satisfied

Are all non-DS nodes, (2)i)<r, and (3)r ∈ H ⁽³⁾ (i) Then will be

Node pair candidate CS node pair set CS for joining DS node i to DS node r _ir And counting the 1 st hop node in the candidate node pair in a set CS = ∑ Σ _r CS″ _ir ,r>i,r∈H ⁽³⁾ (i) The number of occurrences in (a);

for the

If the candidate CS node set CS ″) _ir 1 st hop node in

Is CS node or has been elected as CS node, electing node x is the 1 st hop CS node from node i to node r(ii) a If the CS node does not exist in the 1 st hop or the elected CS node does not exist in the 1 st hop, the node i elects the node o with the largest occurrence frequency in the 1 st hop of the set CS' as the 1 st hop of the CS node; if the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as the 1 st hop of the CS node; if the connectivity is the same, electing the node with the minimum ID as the 1 st hop of the CS node; and the node i counts the occurrence frequency of the candidate 2 nd hop node m on the basis of the selected 1 st hop CS node, and selects the node q with the maximum occurrence frequency as the 2 nd hop of the CS node. If the times of occurrence of the node q and the node u are the same, selecting the node with large connectivity as the 2 nd hop of the CS node; and if the connectivity is the same, electing the node with the smallest ID as the 2 nd hop of the CS node.

In an implementation, the method further comprises the following steps:

the DS node and other DS nodes determine and select the CS node between the DS nodes according to a preset rule;

when the DS node is determined to be selected, notifying other DS nodes of the selected CS node, and when the other DS nodes are determined to be selected, determining the CS nodes selected by the other DS nodes according to the notification;

the CS nodes selected by the DS nodes and the CS nodes and other DS nodes form a connected dominating set.

The embodiment of the invention provides a node for forming a self-organizing network, which comprises:

a processor for reading the program in the memory, performing the following processes:

after the DS node is determined to be the DS node, local information is obtained through neighbor monitoring information, and a local 3-hop topology is constructed, wherein the DS node is the DS node selected by a cluster head selection algorithm in the self-organizing network, and other nodes are 1-hop neighbors of 1 or more cluster head nodes;

selecting a gateway (CS) node for a strict 2-hop DS neighbor according to connection information, and then selecting a CS node for a strict 3-hop DS neighbor node, wherein the strict 2-hop DS neighbor of the node refers to a DS node with the shortest communication distance of 2 hops away from the node, and the strict 3-hop DS neighbor of the node refers to a DS node with the shortest communication distance of 3 hops away from the node;

a DS node and a CS node form a connected dominating set;

a transceiver for receiving and transmitting data under the control of the processor.

In implementation, according to an a-CS algorithm, a gateway CS node is selected for a strict 2-hop DS neighbor, and the selection is performed according to the following rules:

the DS node i reaches the DS node m through the relay node j, if (1) is satisfied

Candidate CS node set CS 'joining DS node i to DS node m' _im And counting the candidate nodes in the set CS' = ∑ Σ _m CS′ _im ,m>i,m∈H ⁽²⁾ (i) Wherein, the common node is a node except for a DS node and a CS node in the network, and the virtual backbone network link is a transmission link formed by the DS node and/or the CS node;

for the

DS node i reaches DS node r through relay nodes j and m ifSatisfy (1)

Are all non-DS nodes, (2)i)<r, and (3)r ∈ H ⁽³⁾ (i) Then will be

for the

If the candidate CS node set CS ″) _ir 1 st hop node in

If the node is a CS node or has been elected as a CS node, the elected node x is a 1 st hop CS node from the node i to the node r; if the CS node does not exist in the 1 st hop or the elected CS node does not exist in the 1 st hop, the node i elects the node o with the largest occurrence frequency in the 1 st hop of the set CS' as the 1 st hop of the CS node; if the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as the 1 st hop of the CS node; if the connectivity is the same, electing the node with the minimum ID as the 1 st hop of the CS node; and the node i counts the occurrence frequency of the candidate 2 nd hop node m on the basis of the selected 1 st hop CS node, and selects the node q with the maximum occurrence frequency as the 2 nd hop of the CS node. If the times of occurrence of the node q and the node u are the same, selecting the node with high connectivity as the 2 nd hop of the CS node; and if the connectivity is the same, electing the node with the smallest ID as the 2 nd hop of the CS node.

In an implementation, the method further comprises the following steps:

determining and selecting CS nodes among the DS nodes with other DS nodes according to a preset rule;

when the selection of the node is determined, notifying other DS nodes of the selected CS node, and when the selection of other DS nodes is determined, determining the CS nodes selected by other DS nodes according to the notification;

An embodiment of the present invention provides a gateway node selection apparatus, including:

the topology construction module is used for acquiring local area information through neighbor monitoring information and constructing a local 3-hop topology after determining that the node is a cluster head DS node, wherein the DS node is a DS node selected by a cluster head selection algorithm in a self-organizing network, and other nodes are 1-hop neighbors of 1 or more cluster head nodes;

the gateway selection module is used for selecting a CS node for a strict 3-hop DS neighbor node after selecting a gateway CS node for the strict 2-hop DS neighbor according to the connection information, wherein the strict 2-hop DS neighbor of the node refers to the DS node with the shortest communication distance of 2 hops away from the node, and the strict 3-hop DS neighbor of the node refers to the DS node with the shortest communication distance of 3 hops away from the node;

and the connected dominating set forming module is used for forming a connected dominating set by the DS node and the CS node.

An embodiment of the present invention provides a computer-readable storage medium, which stores a computer program for executing the above gateway node selection method.

The invention has the following beneficial effects:

in the technical scheme provided by the invention, firstly, after a cluster head node is elected through a cluster head selection algorithm, a local 3-hop topology is constructed, so that the election of the gateway is determined by the cluster head node according to 3-hop local information.

Furthermore, a gateway CS node is selected for a strict 2-hop DS neighbor according to the connection information, and a CS node is selected for a strict 3-hop DS neighbor on the basis.

Furthermore, the gateway is used for connecting a plurality of cluster heads, so that the cluster head selection gateway can comprehensively utilize neighbor information of the cluster heads, and the number of redundant gateways generated by election is reduced.

Further, since the a-CS algorithm is executed by the cluster head using the local area information, the number of DS nodes in the network is generally less than that of the normal nodes, and thus the number of nodes participating in the algorithm can be significantly reduced.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic flow chart illustrating an implementation of a gateway node selection method according to an embodiment of the present invention;

FIG. 2A is a schematic diagram of a section A of the implementation flow of the A-CS algorithm in the embodiment of the present invention;

FIG. 2B is a schematic diagram of a section B of an implementation flow of the A-CS algorithm in the embodiment of the present invention;

FIG. 2C is a schematic diagram of section C of the implementation flow of the A-CS algorithm in the embodiment of the present invention;

FIG. 2D is a schematic diagram of a section D of the implementation process of the A-CS algorithm in the embodiment of the present invention;

FIG. 2E is a schematic diagram of section E of the implementation flow of the A-CS algorithm in the embodiment of the present invention;

FIG. 2F is a schematic diagram of section E of the implementation flow of the A-CS algorithm in the embodiment of the present invention;

FIG. 3 is a schematic diagram of a mobile ad hoc network structure with 16 nodes according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating a DS node completing a CS election in a first process according to an embodiment of the present invention;

FIG. 5 is a diagram illustrating a DS node completing CS election in a second process according to an embodiment of the present invention;

fig. 6 is a diagram illustrating the result of the operation of the a-CS algorithm by the 32-node mobile ad hoc network in the embodiment of the present invention;

fig. 7 is a schematic structural diagram of nodes forming an ad hoc network according to an embodiment of the present invention.

Detailed Description

The inventor notices in the process of invention that:

first, a conceptual and definitional explanation is made for the description.

The layering of the mobile ad hoc network is an important way for solving the problem of scalability, the clustering is one of important means for realizing the layering of the mobile ad hoc network, and the efficiency of a clustering algorithm directly influences the performance of a mobile ad hoc network application system. In addition, the cluster structure formed by clustering can provide various services for network management. Currently, researchers usually study clustering technology by means of relevant theories of graph theory, improve clustering algorithm, and optimize hierarchical structure of mobile ad hoc network. For ease of description and analysis, a widely used general model of wireless mobile ad hoc networks is used herein to abstract nodes in the network as points in graph theory and communication links between nodes as edges in graph theory, and the following definitions are used.

Definition 1 (undirected graph): let G = < V, E >. V denote a set of nodes, E denotes a set of edges. There is an edge (x, y) between nodes x and y, then x and y are one-hop neighbor nodes that can communicate with each other. And if G is a connected undirected graph without self-loops and at most one edge exists between any two nodes in G, the G is called a simple undirected graph.

Definition 2 (dominance set and dominance number): d is a subset of nodes of the graph G = < V, E >, for any node V of G, either V belongs to D or is adjacent to one of the nodes in D, then D is called an allocation set of the graph G. If D is no longer an dominance set after any element is removed from the D set, then D is called a minimal dominance set. The dominating set with the least number of nodes in all dominating sets of the graph G is called the minimum dominating set, and the number of nodes in the minimum dominating set is called the dominating number of the graph G.

Definition 3 (connected dominance set): d is an Dominating Set of graph G, C is a subset of nodes E in the graph, and if the node subsets formed by CD = D £ C are Connected in graph G, the subset CD is called CDs (Connected organizing Set).

Definition 4 (connectivity): the number of one-hop neighbor nodes of a node is referred to as the connectivity of the node.

Definition 5 (clusters and clusterheads): a cluster in a wireless network is formed by a group of nodes C, wherein

A group of nodes in the neighborhood is generally grouped into a cluster, and the behavior of the nodes in the cluster is coordinated and controlled by a coordinating node (central node), which is called a cluster head.

Definition 6 (gateway): the nodes in the clustered network that implement inter-cluster data transmission are called gateways.

Definition 7 (network dominance set): the network allocation set is defined as a set formed by all cluster heads and gateways in the network, and the virtual backbone network is a network allocation set.

A general gateway selection algorithm is explained below.

In the plane structure, all nodes have equal positions, so the plane structure can be called as a peer-to-peer structure; in the hierarchical structure, the network is divided into clusters, each cluster consists of a cluster head and a plurality of cluster members, the cluster heads form a higher-level network, and the clusters can be formed in the higher-level network. In a clustered network, inter-cluster communication is accomplished by means of gateway nodes.

In addition, the gateway in the present solution can be abstracted as a part of the connected dominating set in graph theory, i.e. the connected set connecting the dominating set (the set of cluster heads). In broadcast transmission, the connection dominating set is used as an MPR (Multi-Point Relay) node of broadcast data, so that the number of the broadcast data is reduced while the data is broadcast in the whole network, and the network load is reduced; in the routing selection, a virtual backbone network of a data route is constructed by communicating a branch set, and the multi-hop transmission of unicast data is completed by adopting a corresponding routing mechanism; in the network clustering, the connected dominating set is equivalent to a cluster head and gateway set in a 1-hop clustering (namely, the distance between all nodes in a cluster and the cluster head is 1 hop) network, namely, the network dominating set.

In one scheme, the development and research of an MPR mechanism and an algorithm in a mobile ad hoc network are described, and the contribution to the MPR mechanism and the algorithm is introduced on the basis of the previous work, so that an Extended enhanced-independent multi-point relay (EEMPR) algorithm is proposed. The original MPR is a source-dependent (broadcast-dependent) strategy, i.e. during the broadcast, the set of forwarding nodes is determined by the source node of the broadcast and the communication delay, and a greedy algorithm (algorithm 1) is used to give the set of forwarding nodes MPR (i) for node i. On the basis, a new, local and non-information-source-dependent algorithm is proposed based on the MPR algorithm, and a rule I and a rule II are defined. Then, an improved rule one is defined on the basis, and an EMPR (Enhanced source-independent MPR) algorithm (algorithm 2) is provided, so that redundant nodes in the CDS are reduced, and the algorithm efficiency is improved. Furthermore, an improved rule II is provided in the scheme, an EEMPR algorithm (algorithm 3) is provided, and a forwarding node capable of covering a node 2-hop neighbor set is selected by using 3-hop neighborhood information of the node, so that redundant nodes in a CDS are further reduced, and the algorithm efficiency is improved.

If a node belongs to the connected dominating set, it needs to satisfy any one of the following rules:

rule one is as follows: the ID of a node is smaller than the ID of any of its neighbors.

Rule two: the node is elected as a forwarding node by the neighbor node with the smallest ID.

On the basis of the above two rules, other researchers have given the following improved rules:

the first improved rule is as follows: the ID of the node is smaller than that of any neighbor node of the node, and meanwhile, the node has unconnected neighbor nodes.

And (5) improving a rule II: the node is directly elected as a forwarding node by the neighbor node with the smallest ID, or the node is indirectly elected as the forwarding node by the node with the ID smaller than all the 1-hop neighbor nodes in the 2-hop neighbor nodes.

In the algorithm, an MIS (Maximum Independent Set) is constructed by using a dyeing algorithm through an initiating node, then a connection node is obtained from nodes which are not Maximum Independent sets by using an approximate greedy algorithm, and finally a minimum connected dominating Set is formed by the connection node and the Maximum Independent Set. The ECDS (Efficient Connected learning Set) algorithm proposed by the article has certain advantages in the size of the Connected learning Set, the average energy consumption and the network life.

There are also schemes that focus on the performance of the classical local information CDS algorithm. On the basis of reviewing a CDS global algorithm, a 1-hop local information algorithm and a 2-hop local information algorithm, a corresponding improvement strategy is provided; and proves that the approximation rate (approximation rate) of the improved 2-hop local information algorithm is (H (2 delta + 1) + 1), and the approximation rate (approximation rate) of the improved 1-hop local information algorithm is (H (delta) +2 \sqrtH (delta) } + 1). However, the algorithms studied in the scheme are all diffusion algorithms started from one initial node, the whole algorithm needs to be completed in multiple cycles, and in essence, except the initial node, other points obtain additional information gain when local information calculation is performed. In addition, the 1-hop local information algorithm mentioned in the text actually uses the connectivity of the 1-hop node, which requires information of two neighbors, and is called as a 2-hop local information algorithm in most of the articles. Similarly, the 2-hop local information algorithm uses information of 3-hop neighbors, and most researchers refer to the 3-hop local information algorithm.

The concept and algorithm of UCDS (unified CDS) are given for the first time by combining the concept and algorithm of CDS. The algorithm is a distributed CDS algorithm with reasonable computational complexity and low system overhead. Because the calculation is based on the 2-hop information of the node and the UCDS rules given in the scheme are applied sequentially, the algorithm is very stable. Simulation results show that the number of the nodes in the UCDS given by the algorithm accounts for about 15% -44% of the total number of the nodes in the network. In addition, the scheme focuses on researching two Connected Dominating Set algorithms, namely E-CDS (Essential Connected Dominating Set) and UCDS (UCDS), and the fault tolerance capability of the improved algorithms in the mobile ad hoc network. In the scheme, NS-3 simulation software is used for establishing a simulation scene, the influence of the increase and decrease of nodes, the movement of the nodes and the change of flow on a CDS algorithm in a sparse network and a dense network is researched, and the following conclusion is given:

1. the greater the rate of topology change (node departure or movement), the greater the number of CDS nodes generated in the network;

2. the retransmission can improve the probability of successful data transmission, but cannot improve the adaptability of the network to the topology change;

3. the performance of UCDS is slightly better than that of E-CDS.

However, the existing gateway selection algorithm or connected domination set algorithm performs election of a gateway or a connected set by using local area information of candidate nodes, and the gateway generated by election is often not optimal and generates more redundant gateways.

Based on the above, the embodiment of the present invention provides a gateway selection scheme based on a cluster head, where the gateway node is elected using local neighbor information of the cluster head, so that the cluster head and the gateway together form a connected subnet, which can be used to solve the problems of inter-cluster communication, routing, and the like of a wireless ad hoc network, a sensor network, and other centerless wireless networks. The following describes embodiments of the present invention with reference to the drawings.

Fig. 1 is a schematic flowchart of an implementation method of a gateway node selection, as shown in the figure, the method may include:

101, a cluster head DS node acquires local area information through neighbor monitoring information and constructs a local area 3-hop topology, wherein the DS node is a DS node selected by a cluster head selection algorithm in a self-organizing network, and other nodes are 1-hop neighbors of 1 or more cluster head nodes;

102, selecting a gateway (CS) node for a strict 2-hop DS neighbor by a DS node according to connection information, and then selecting a CS node for a strict 3-hop DS neighbor by the DS node, wherein the strict 2-hop DS neighbor of the node is the DS node with the shortest communication distance of 2 hops away from the node, and the strict 3-hop DS neighbor of the node is the DS node with the shortest communication distance of 3 hops away from the node;

and step 103, forming a connected dominating set by the DS nodes and the CS nodes.

In implementation, it can be seen that the formed connected dominating set includes a cluster head and a gateway, and the connected dominating set can be used for topology control, routing, data transmission, and the like of the mobile ad hoc network.

The node implementing the scheme is a cluster head node or a called DS node in the network. In addition, in the scheme, after clustering, a node in the network is either a cluster head or the communication distance between the node and the cluster head is 1 hop, namely the network clustering range is 1 hop, and the distance between the cluster head and the cluster head is 3 hops at most for adjacent clusters.

In the implementation, the method can further comprise the following steps:

Specifically, the node for selecting the gateway is a cluster head or DS node in the network. The algorithm provided by the scheme is also a distributed algorithm essentially, and each cluster head determines the CS nodes between the cluster head and other cluster head nodes according to the information obtained by the cluster head, so that a plurality of gateway selection nodes in the network are provided, namely all the cluster heads. The following embodiments also provide specific embodiments in which the preset rule is selected according to a node with a small ID.

Since few nodes are allowed to dominate the selection weight, algorithm convergence and optimization are facilitated. The minority nodes refer to cluster head nodes in the network.

Specifically, for any cluster head node in the network, the CS node needs to be elected according to four rules provided in the following embodiments in this scheme, and the simple process is as follows: (1) the cluster head node a acquires the local information to obtain the relationship with other cluster head nodes b, c and d in the local area range. (2) The cluster head node a determines whether CS nodes need to be selected for the cluster head nodes b, c, and d (see the specific determination manner in 4 rules given in the following embodiments), for example, if there are two-hop neighbors between ab and no common 1-hop cluster head neighbor, and the ID of a is smaller than the ID of b, the cluster head a is responsible for selecting CS nodes between ab. (3) And the cluster head a selects the CS according to the scheme.

In implementation, the gateway selection node selects a gateway CS node for a strict 2-hop DS neighbor according to the connection information, and then selects a CS node for a strict 3-hop DS neighbor on the basis, which is selected according to an a-CS algorithm.

In implementation, according to an a-CS algorithm, the gateway selection node selects a gateway CS node for a strict 2-hop DS neighbor according to connection information, and selects according to the following rule:

[ candidate CS rule 1 ] DS node i reaches DS node m through relay node j, if (1) is satisfied

CS rule 1 for

Node i from set CS of candidate CS nodes' _im To elect the node with the most occurrence number in the set CSo as a CS node; if the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as a CS node; and if the connectivity is the same, electing the node with the minimum ID as the CS node.

In implementation, according to an A-CS algorithm, a CS node is selected for a strict 3-hop DS neighbor node on the basis, and the selection is carried out according to the following rules:

[ candidate CS rule 2 ] DS node i reaches DS node r through relay nodes j and m, if (1) is satisfied

Are all non-DS nodes, (2)i)<r, and (3)r ∈ H ⁽³⁾ (i) Then will be

The node pair joins the candidate CS node pair set CS ″, from DS node i to DS node r _ir And counting the 1 st hop node in the candidate node pair in a set CS = ∑ Σ _r CS″ _ir ,r>i,r∈H ⁽³⁾ (i) The number of occurrences in (1);

CS rule 2 for

If the candidate CS node set CS ″) _ir 1 st hop node in

If the node is a CS node or has been elected as a CS node, the elected node x is a 1 st hop CS node from the node i to the node r; if the CS node or the elected CS node does not exist in the 1 st hop, the node i elects the node o with the largest occurrence frequency in the 1 st hop of the set CS' as the 1 st hop of the CS node; if the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as the 1 st hop of the CS node; if the connectivity is the same, electing the node with the minimum ID as the 1 st hop of the CS node; and the node i counts the occurrence frequency of the candidate 2 nd hop node m on the basis of the selected 1 st hop CS node, and selects the node q with the maximum occurrence frequency as the 2 nd hop of the CS node. If node q and node u occur the same number of times,selecting the node with high connectivity as the 2 nd hop of the CS node; and if the connectivity is the same, electing the node with the smallest ID as the 2 nd hop of the CS node.

The reference symbols will be described below, and specific meanings of mathematical symbols used in the practice are shown in table 1 below.

Table 1: symbol correspondence table:

the communication domination set passes through a relay node j and reaches any one DS node of another DS node through 2 hops;

the CS node is selected for the 2-hop DS neighbor node;

the communication dominance set passes through the relay nodes j and m and reaches any one DS node of another DS node through 3 hops;

representing the CS nodes elected by the 3-hop DS neighbor nodes.

The following describes an a-CS (advanced connecting set) algorithm provided in the present solution based on the deficiencies of the existing algorithms, the a-CS algorithm is a name given for convenience of description in implementation, and the name of the algorithm does not contain any limitation.

The A-CS algorithm is a local area centered gateway selection algorithm based on partial topology information, a cluster head (DS node) elects to generate a gateway (CS node) by taking the cluster head as a center according to the collected partial topology information, and the connection is established with other cluster heads in a 3-hop range through the gateway. The core idea of the A-CS algorithm is to divide the gateway selection algorithm into two processes, and to select as few gateway nodes as possible by synthesizing known information. In the first process, the central node (cluster head) integrates known local area topology information and selects as few gateways as possible for other cluster heads with IDs larger than the cluster head in a 2-hop range; in the second process, the central node (cluster head) selects as few gateways as possible for other cluster heads with ID larger than self in the 3-hop range by using the election result of the first process; in addition, the two processes are the sequence of algorithm operation and are all completed in the same period.

The A-CS algorithm is to select a connected node (CS) on the basis of a Dominating Set (DS) and construct a connected dominating set (virtual backbone network), namely to select a gateway node on the basis of cluster heads, so that the cluster heads can communicate through a gateway. When the network is initialized, the node marks the self state as W (White); if the node is selected as a DS node (cluster head), the self state is marked as B (Black); if the node is not selected as a DS node but its 1-hop neighbor node is selected as a DS node, it marks itself as G (Gray). When the algorithm is executed, a node i (the node state is B) elected as a DS collects information of other DS nodes r in 1-hop, 2-hop and 3-hop neighbors, the relay node conditions of links from the node i to all DS neighbor nodes r are integrated, and the connected nodes o as few as possible are elected, so that the node i and all DS nodes r in 3 hops form a connected set. In the first process, a DS node i elects to generate a connected node (CS node) for a DS node in a strict 2-hop neighborhood; in the second procedure, using the results generated in the first procedure, DS node i elects to generate a CS node for DS nodes in its strict 3-hop neighborhood.

The A-CS algorithm is executed in a distributed mode by DS nodes by using local information, on one hand, the number of nodes participating in the algorithm can be obviously reduced, because the number of DS nodes in a network is less than that of common nodes under general conditions, few nodes are led to dominate the selection weight in the distributed algorithm, and the convergence and optimization of the algorithm are facilitated; on the other hand, the CS node is used for connecting a plurality of DS nodes, so that the DS nodes select the CS node, the neighbor information of the DS can be comprehensively utilized, and the number of redundant CS nodes generated by election is reduced.

The A-CS algorithm is composed of the following 4 rules, wherein a candidate CS rule 1 and a CS rule 1 are DS nodes in a node strict 2-hop neighbor and elect a CS node, and a candidate CS rule 2 and a CS rule 2 are DS nodes in a node strict 3-hop neighbor and elect a CS node pair.

Candidate CS rule 1: the DS node i reaches the DS node m through the relay node j, if (1) is satisfied

Are all common nodes (state is G), (2)i)<m、③m∈H ⁽²⁾ (i) (4)i no 3-hop virtual backbone network link exists between j, then it will be

Candidate CS node set CS 'joining DS node i to DS node m' _im And counting the candidate nodes in the set CS' = ∑ Σ _m CS′ _im ,m>i,m∈H ⁽²⁾ (i) Wherein, the common node is a node except for a DS node and a CS node in the network, and the virtual backbone network link is a transmission link formed by the DS node and/or the CS node.

CS rule 1: for the

Node i from set CS of candidate CS nodes' _im Node o, which appears most frequently in the set CS', is elected as the CS node. If the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as a CS node; and if the connectivity is the same, electing the node with the minimum ID as the CS node.

Candidate CS rule 2: DS node i reaches DS node r through relay nodes j and m, if (1) is satisfied

Are all non-DS nodes, (2)i)<r、③r∈H ⁽³⁾ (i) Then will be

Node pair candidate CS node pair set CS for joining DS node i to DS node r _ir And counting the 1 st hop node in the candidate node pair in a set CS = ∑ Σ _r CS″ _ir ,r>i,r∈H ⁽³⁾ (i) Number of occurrences in (c).

CS rule 2: for the

If the candidate CS node set CS ″) _ir 1 st hop node in

If the node is a CS node or has been elected as a CS node according to the candidate CS rule 2, the elected node x is the 1 st hop CS node from the node i to the node r. If there is no CS node at hop 1 or a CS node has been elected according to candidate CS rule 2, node i elects node o, which appears most frequently in hop 1 of the set CS', as hop 1 of the CS node. If the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as the 1 st hop of the CS node; and if the connectivity is the same, electing the node with the smallest ID as the 1 st hop of the CS node. And the node i counts the occurrence frequency of the candidate 2 nd hop node m on the basis of the selected 1 st hop CS node, and selects the node q with the maximum occurrence frequency as the 2 nd hop of the CS node. If the times of occurrence of the node q and the node u are the same, selecting the node with high connectivity as the 2 nd hop of the CS node; and if the connectivity is the same, electing the node with the smallest ID as the 2 nd hop of the CS node.

The implementation of the a-CS algorithm is explained below, and the implementation steps of the algorithm may be as follows.

Fig. 2A is a schematic diagram of a section a of the implementation flow of the a-CS algorithm, and as shown in the figure, this section may be as follows:

step 201, after starting, executing a P-DS algorithm, and periodically monitoring state change, wherein the P-DS algorithm is a cluster head election algorithm, and other cluster head election algorithms can also be adopted;

step 202, judging whether the self state is B, if so, turning to step 203, otherwise, turning to step 201;

step 203, traversing and inquiring whether the state of the node j in the 1-hop neighbor list is B;

step 204, judging whether the state of the neighbor j is B, if so, turning to step 205, otherwise, turning to step 206;

step 205, judging whether all neighbors are traversed, if so, turning to step 214, and otherwise, turning to step 203;

in this section, first, an arbitrary node i in the network determines whether its own state is B. If yes, participating in the A-CS algorithm; if not, then not participating.

Fig. 2B is a schematic diagram of a section B of the implementation process of the a-CS algorithm, and as shown in the figure, this section may be as follows:

step 206, traversing and inquiring whether the state of the 1-hop neighbor m of the neighbor j is B;

step 207, judging whether the state of the neighbor m of the neighbor j is B, if so, turning to step 208, otherwise, turning to step 213;

step 208, comparing the ID sizes of the neighbor m of the node i and the neighbor j thereof;

step 209, judging whether the ID of the node i is smaller than the ID of the node m, if so, turning to step 210, otherwise, turning to step 213;

step 210, judging whether a 1-hop, 2-hop and 3-hop virtual backbone network link exists between the node i and the node m;

step 211, judging whether a virtual backbone network link exists, if so, switching to step 213, otherwise, switching to step 212;

step 212, adding the node j into a candidate CS node set from the node i to the node m, and turning to step 213;

step 213, judging whether the neighbors of all the neighbors j are traversed, if so, turning to step 205, otherwise, turning to step 206;

in this segment, a node i participating in the a-CS algorithm queries whether the state of a node j in its 1-hop neighbor list is B. If yes, no processing is carried out, and the state of the next neighbor k is continuously inquired; if not, inquiring whether the state of the node m in the 1-hop neighbor list of the 1-hop neighbor node j is B.

If the state of the node m is not B, no processing is carried out; and if the state of the node m is B, judging whether the ID of the node i is smaller than the ID of the node m.

If not, no processing is performed.

If yes, sequentially judging whether a 1-hop, 2-hop or 3-hop virtual backbone network link exists between the node m and the node i, wherein the virtual backbone network link is a transmission link formed by DS nodes and/or CS nodes. If the virtual backbone network link exists, no operation is carried out; if not, then node j (State is G) is added to the set of candidate CS nodes CS 'from node i (State is B) to node m (State is B)' _im 。

Fig. 2C is a schematic diagram of a section C of the implementation process of the a-CS algorithm, and as shown in the figure, this section may be as follows:

step 214, counting the occurrence times of all candidate nodes j in the candidate CS set;

step 215, judging whether a CS node exists in candidate nodes from the node i to the node m, if so, turning to step 222, otherwise, turning to step 216;

step 216, selecting the node with the largest number of times from the candidate nodes from the node i to the node m;

step 217, judging whether a plurality of nodes with the most times exist, if so, turning to step 219, otherwise, turning to step 218;

step 218, electing the node o with the largest occurrence frequency as the CS node, and turning to step 222;

step 219, judging whether a plurality of nodes with the largest connectivity exist, if so, turning to step 221, otherwise, turning to step 220;

step 220, electing the node o with the largest connectivity as a CS node, and turning to step 222;

step 221, electing the node o with the smallest ID as a CS node;

step 222, judging whether all the nodes m are traversed;

step 223, judging whether the traversal is performed, if so, turning to step 224, otherwise, turning to step 215;

in this paragraph, the 2C paragraph is repeated until a node i is found

And the status is the set CS of all candidate CS nodes j of B' _im And counting the candidate node j in the candidate node set CS' = sigma _m CS′ _im The number of occurrences in (c).

Judging the candidate CS node set CS 'from node i (state is B) to node m (state is B)' _im Whether there is a CS node.

If so, do nothing;

if not, a set CS 'of candidate CS nodes from node i (State B) to node m (State B)' _im The node o with the largest number of occurrences in the set CS' is elected as the CS node. If the times of occurrence of the node o and the node u are the same, selecting the node with large connectivity as a CS node; and if the connectivity is the same, electing the node with the smallest ID.

Fig. 2D is a schematic diagram of a section D of the implementation process of the a-CS algorithm, and as shown in the figure, this section may be as follows:

step 224, the node i starts to elect a CS node for the node r of which the 3-hop neighbor is in the state of B;

step 225, traversing and inquiring whether the state of the node j in the 1-hop neighbor list is B;

step 226, judging whether the state of the neighbor j is B, if yes, turning to step 238, otherwise, turning to step 227;

step 238, judging whether all neighbors are traversed, if yes, turning to step 239, and if not, turning to step 225;

Fig. 2E is a schematic diagram of a section E of the implementation flow of the a-CS algorithm, and as shown in the figure, this section may be as follows:

step 227, traversing and inquiring whether the state of the 1-hop neighbor m of the neighbor j is B;

step 228, judging whether the state of the neighbor m of the neighbor j is B, if so, turning to step 237, otherwise, turning to step 229;

step 229, traversing and inquiring whether the state of the neighbor r of the 2-hop neighbor m is B;

step 230, judging whether the neighbor r state of the 2-hop neighbor m is B, if so, turning to step 231, otherwise, turning to step 236;

231, comparing the ID of the node i and the 3-hop neighbor m thereof;

step 232, judging whether the ID of the node i is smaller than the ID of the node m, if so, turning to step 233, otherwise, turning to step 236;

step 233, judging whether 1-hop or 2-hop links exist between the node i and the node r, and whether a virtual backbone network node exists in all 3-hop links;

step 234, judging whether all the products are negative, if yes, turning to step 235, and if not, turning to step 236;

step 235, adding the node j and the node m into the candidate CS set from the node i to the node r, and turning to step 236;

step 236, judging whether all neighbors of the 2-hop neighbor m are traversed, if yes, turning to step 237, and otherwise, turning to step 229;

step 237, judging whether the neighbors of all the neighbors j are traversed, if so, turning to step 238, otherwise, turning to step 227;

in the section, a 2D section is connected, and if the state of the node m is B, no processing is performed; and if the state of the node m is not B, inquiring whether the state of the neighbor node r of the 2-hop neighbor node m is B or not.

And if the state of the node r is B, judging whether the ID of the node i is smaller than that of the node r. If not, no action is taken. If yes, judging whether 1-hop or 2-hop links exist between the node i and the node r. If so, do nothing; and if not, judging whether the virtual backbone network nodes exist in all the 3-hop links.

If the virtual backbone network node exists, no operation is performed; if not, adding node j (with the state of G) and node m (with the state of G) into a candidate CS node pair set from node i (with the state of B) to node r (with the state of B)CS″ _ir 。

Repeating the steps until the nodes i to i are found

And set CS of all candidate CS node pairs (j, m) for nodes with state B _ir 。

Fig. 2F is a schematic diagram of a section E of the implementation process of the a-CS algorithm, and as shown in the figure, this section may be as follows:

step 239, inquiring whether a CS node exists in the 1 st hop node of the candidate CS node set from the node i to the node r;

step 240, judging whether a CS node exists, if so, turning to step 247, otherwise, turning to step 241;

step 241, counting the occurrence times of the 1 st hop candidate node in the candidate node set, and selecting the 1 st hop node with the largest occurrence times;

step 242, judging whether a plurality of nodes with the most times exist, if so, turning to step 244, otherwise, turning to step 243;

step 243, electing the node o with the largest frequency of elections as the 1 st hop CS node, and turning to step 248;

step 244, judging whether a plurality of nodes with the largest connectivity exist, if so, turning to step 246, otherwise, turning to step 245;

step 245, electing the node o with the largest connectivity as the 1 st hop CS node, and turning to step 248;

step 246, electing the node o with the smallest ID as the 1 st hop CS node, and turning to step 248;

step 247, selecting the CS node o with the smallest ID as the 1 st hop CS node, and turning to step 248;

step 248, selecting the 2 nd hop candidate node with the most occurrence times based on the 1 st hop CS node o;

step 249, judging whether a plurality of nodes with the most times exist, if so, turning to step 251, and otherwise, turning to step 250;

step 250, electing the node q with the largest frequency of occurrence as the 2 nd hop CS node, and turning to step 254;

251, judging whether a plurality of nodes with the maximum connectivity exist, if so, turning to 253, otherwise, turning to 252;

step 252, electing the node q with the largest connectivity as a 2 nd hop CS node, and turning to step 254;

step 253, electing the node q with the minimum ID as the 2 nd hop CS node, and turning to step 254;

and 254, judging whether all the nodes r are traversed, if so, ending, and otherwise, turning to a step 239.

In this paragraph, a candidate CS node set CS ″, from node i (state B) to node r (state B), is queried _ir 1 st hop node in

Whether a CS node exists.

If yes, selecting the node x with the smallest ID as the 1 st hop CS node, and continuing to execute the following steps: and on the basis of the selected 1 st hop CS node, counting the occurrence times of the candidate 2 nd hop node m. And then selecting the node q with the largest occurrence number as the 2 nd hop of the CS node. If the times of occurrence of the node q and the node u are the same, selecting the node with high connectivity as the 2 nd hop of the CS node; and if the connectivity is the same, electing the node with the smallest ID as the 2 nd hop of the CS node.

If not, counting the 1 st hop candidate node j in the candidate node set CS' = ∑ sigma _r CS″ _ir From node i (state B) to node r (state B) of the set of candidate CS nodes CS ″) _ir Electing the node o with the largest number of occurrences in the 1 st hop of the set CS "as the 1 st hop of the CS node. If the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as the 1 st hop of the CS node; and if the connectivity is the same, electing the node with the smallest ID as the 1 st hop of the CS node.

The following is an example.

Fig. 3 is a schematic structural diagram of a mobile ad hoc network including 16 nodes, as shown in the figure, it is assumed that there are 16 nodes in the mobile ad hoc network, and connection relationships among the nodes are as shown in fig. 3, nodes 2, 3, 7, and 14 are elected as cluster heads (DS nodes) by a cluster head selection algorithm, as shown by black nodes in the figure and labeled as state B, and other nodes are 1-hop neighbors of 1 or more cluster head nodes.

According to the A-CS algorithm, the DS node obtains local information through neighbor monitoring information, and a local 3-hop topology is constructed. DS node 2 finds that there are DS nodes 3 and 7 in strict 2-hop neighbors with normal node connection (here, strict 2-hop DS neighbors means that the shortest link between two DS nodes is 2 hops), there is DS node 14 in 3-hop neighbors, and its own ID is smaller than the IDs of all DS neighbors. Therefore, node 2 first selects a gateway (CS node) for the 2-hop DS neighbor according to the connection information, and then selects a gateway (CS node) for the 3-hop DS neighbor on this basis.

Fig. 4 is a schematic diagram of CS election performed by the DS node in the first process, and as shown in the figure, in this example, the node 2 may communicate with the node 7 through the node 10, and may communicate with the node 7 through the

nodes

10 and 5.

Thus, for DS node 2, according to candidate CS rule 1, node 10 is CS' = ∑ Σ _m CS′ _im ,m>i,m∈H ⁽²⁾ (i) 2 in the set and 1 in node 5; and then according to the CS rule 1, the DS node 2 elects a node 10 to connect 2-hop DS neighbors 3 and 7 for the CS node, so as to form the network topology graph as shown. DS node 3 elects node 10 as the CS node between it and DS node 7 according to the same rule. Because the ID of node 3 is greater than the ID of node 2, node 3 is not responsible for the selection of the CS node connected to node 2; the same reason node 7 is not responsible for the selection of the CS nodes connected to nodes 2 and 3.

After the DS node selects a CS node for a strict 2-hop DS neighbor through a first process, the CS node is selected for a strict 3-hop DS neighbor according to a candidate CS rule 2 and a CS rule 2. At this time, the DS nodes 2, 3, and 7 all find that there is a strict 3-hop DS neighbor node 14 connected by a common node, where the strict 3-hop DS neighbor means that the shortest link between two DS nodes is 3 hops, that is, the shortest link between the nodes 2, 3, and 7 and the node 14 is 3 hops, and the 3-hop links between them are all formed by common nodes.

At this time, the state of the node in the network is based on the state of the node before the first process, that is, the state of the CS node generated in the first process is still processed according to the normal node, because the first process and the second process of the algorithm are completed after being selected in the same period, and the state of the node is not updated. Then, the DS nodes with smaller IDs in strict 3-hop DS neighbor pairs connected by the non-DS nodes select a CS pair for the DS neighbor pair according to a second process of an A-CS algorithm and independently form a connected link.

FIG. 5 is a schematic diagram of CS election in the second process of completing by DS node, as shown in the figure, in this example, node 2 searches for a candidate CS node pair set CS 'according to candidate CS rule 2' _ir Finding 2 node pairs (10,16), (1,16) to DS node 14, with the 1

st hop node

10,1 in the node pair in the set CS "= ∑ Σ _r CS″ _ir ,r>i,r∈H ⁽³⁾ (i) The number of occurrences in (a) is 1. Then, the node 2 finds that the node 10 has been elected as a CS node in the first procedure according to the election rule of the CS rule 2, and thus determines the node as a 1 st-hop CS node of the second procedure, and the corresponding elected node 16 is a 2 nd-hop CS node. For DS node 3, because there is only one link (10,16) to DS node 14, elected node pair (10,16) is a CS node, and similarly, DS node 7 also elects (10,16) as a CS node. After the second process is finished, the network finishes the election of the CS node (gateway), and a connected dominating set is formed by the DS node (cluster head) and the CS node (gateway), namely, the communication between the cluster heads is realized through the gateway.

Fig. 6 is a schematic diagram of a result of operating the a-CS algorithm by a 32-node mobile ad hoc network, as shown in the figure, when there are 32 nodes in the network, a CS node selected by the a-CS algorithm is as shown in fig. 6, and a connected dominating set of four network topologies is shown in the figure. Wherein, the green node is a DS node (cluster head); the red nodes are common nodes and are respectively connected with 1 or more cluster heads; and the grey nodes are CS nodes generated by election according to an A-CS algorithm, so that the DS nodes are mutually communicated to form a communication dominating set.

Based on the same inventive concept, the embodiment of the present invention further provides a node forming an ad hoc network, a gateway node selection apparatus, and a computer-readable storage medium, and because the principle of solving the problem of these devices is similar to a gateway node selection method, the implementation of these devices can refer to the implementation of the method, and repeated details are not repeated.

When the technical scheme provided by the embodiment of the invention is implemented, the implementation can be carried out as follows.

Fig. 7 is a schematic diagram of a node structure forming an ad hoc network, as shown in the figure, the node includes:

the processor 700, which is used to read the program in the memory 720, executes the following processes:

a DS node and a CS node form a connected dominating set;

a transceiver 710 for receiving and transmitting data under the control of the processor 700.

DS node i reaches DS node m through relay node j, if (1) is satisfied

for the

DS node i reaches DS node r through relay nodes j and m, if (1) is satisfied

Are all non-DS nodes, (2)i)<r, and (3)r ∈ H ⁽³⁾ (i) Then will be

for

If the candidate CS node set CS ″) _ir 1 st hop node in

If the node is a CS node or elected as a CS node, the elected node x is a 1 st hop CS node from the node i to the node r; if the CS node does not exist in the 1 st hop or the elected CS node does not exist in the 1 st hop, the node i elects the node o with the largest occurrence frequency in the 1 st hop of the set CS' as the 1 st hop of the CS node; if the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as the 1 st hop of the CS node; if the connectivity is the same, electing the node with the smallest ID as the 1 st hop of the CS node; and the node i counts the occurrence frequency of the candidate 2 nd hop node m on the basis of the selected 1 st hop CS node, and selects the node q with the maximum occurrence frequency as the 2 nd hop of the CS node. If the times of occurrence of the node q and the node u are the same, selecting the node with high connectivity as the 2 nd hop of the CS node; and if the connectivity is the same, electing the node with the smallest ID as the 2 nd hop of the CS node.

In an implementation, the method further comprises the following steps:

Where in fig. 7, the bus architecture may include any number of interconnected buses and bridges, with various circuits being linked together, particularly one or more processors represented by processor 700 and memory represented by memory 720. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The transceiver 710 may be a plurality of elements, i.e., including a transmitter and a transceiver, providing a means for communicating with various other apparatus over a transmission medium. The processor 700 is responsible for managing the bus architecture and general processing, and the memory 720 may store data used by the processor 700 in performing operations.

For details, refer to the implementation of the above gateway node selection method.

For convenience of description, each part of the above-described apparatus is separately described as being functionally divided into various modules or units. Of course, the functionality of the various modules or units may be implemented in the same one or more pieces of software or hardware in the practice of the invention.

In summary, in the technical solution provided by the present invention, the election of the gateway is determined by the cluster head node according to the 3-hop local area information, and an algorithm with the cluster head as the center in the local area is formed.

Further, the algorithm is divided into two processes, and the result generated in the first process is used in the second process to reduce redundant gateway nodes.

Specifically, the local area elects a gateway by taking the cluster head as the center, and can elect a node more suitable for inter-cluster communication as the gateway.

The a-CS algorithm is performed by the cluster head using local area information, which can significantly reduce the number of nodes participating in the algorithm because the number of DS nodes in the network is generally less than the number of normal nodes.

In the algorithm, a few nodes are led to dominate the selection weight, and the convergence and optimization of the algorithm are facilitated.

The gateway is used for connecting a plurality of cluster heads, so that the cluster head selection gateway can comprehensively utilize neighbor information of the cluster heads, and the number of redundant gateways generated by election is reduced.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A method for selecting a gateway node, comprising:

after determining that the node is a cluster head DS node, obtaining local area information through neighbor monitoring information, and constructing a local area 3-hop topology, wherein the DS node is a DS node selected by a cluster head selection algorithm in a self-organizing network, and other nodes are 1-hop neighbors of 1 or more cluster head nodes;

after selecting a gateway CS node for a 2-hop DS neighbor according to the connection information, the DS node selects a CS node for a 3-hop DS neighbor, wherein the 2-hop DS neighbor of the node refers to a DS node with the shortest communication distance from the node being 2 hops, and the 3-hop DS neighbor of the node refers to a DS node with the shortest communication distance from the node being 3 hops;

a DS node and a CS node form a connected dominating set;

selecting a gateway (CS) node for a 2-hop DS neighbor node according to the connection information, and then selecting a CS node for a 3-hop DS neighbor node according to an A-CS algorithm;

according to the A-CS algorithm, selecting a gateway CS node for a 2-hop DS neighbor according to the connection information, and selecting according to the following rules:

DS node i reaches DS node m through relay node j, if (1) is satisfied

for the

Node i from set CS of candidate CS nodes' _im Electing the node o with the largest occurrence frequency in the set CS' as a CS node; if the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as a CS node; if the connectivity is the same, electing the node with the minimum ID as the CS node;

wherein H ⁽²⁾ (i)＝N ⁽²⁾ (i)-N ⁽¹⁾ (i)；N ⁽²⁾ (i) Is a 2-hop neighbor set of node i, N ⁽¹⁾ (i) A 1-hop neighbor set of a node i;

the communication dominance set passes through the relay node j and reaches any one DS node of another DS node through 2 hops;

denoted CS nodes elected for 2-hop DS neighbor nodes.

2. The method of claim 1, wherein the CS node is selected for a 3-hop DS neighbor node according to an a-CS algorithm, according to the following rules:

DS node i reaches DS node r through relay nodes j and m, if (1) is satisfied

Are all non-DS nodes, (2)i)<r, and (3)r ∈ H ⁽³⁾ (i) Then will be

The node pair joins the candidate CS node pair set CS ″, from DS node i to DS node r _ir And counting the 1 st hop node in the candidate node pair in a set CS = ∑ Σ _r CS″ _ir ,r>i,r∈H ⁽³⁾ (i) The number of occurrences in (a);

for the

If the candidate CS node set CS ″) _ir 1 st hop node in

If the CS node is selected as the CS node or the CS node is selected according to the rule of selecting the gateway CS node for the 2-hop DS neighbor, the selected node x is the 1 st-hop CS node from the node i to the node r; if the CS node does not exist in the 1 st hop or the CS node is elected as the CS node according to the rule of selecting the gateway CS node for the 2-hop DS neighbor, the node o with the most occurrence times in the 1 st hop of the set CS' is elected as the 1 st hop of the CS node by the node i; if the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as the 1 st hop of the CS node; if the connectivity is the same, electing the node with the minimum ID as the 1 st hop of the CS node; the node i counts the occurrence frequency of the candidate 2 nd hop node m on the basis of the selected 1 st hop CS node, and selects the node q with the maximum occurrence frequency as the CS nodeHop 2 of the point; if the times of occurrence of the node q and the node u are the same, selecting the node with high connectivity as the 2 nd hop of the CS node; if the connectivity is the same, electing the node with the minimum ID as the 2 nd hop of the CS node;

representing the CS nodes elected by the 3-hop DS neighbor nodes.

3. The method of claim 1, further comprising:

4. A node forming an ad-hoc network, the node comprising:

selecting a gateway (CS) node for a 2-hop DS neighbor according to connection information, and then selecting a CS node for a 3-hop DS neighbor node, wherein the 2-hop DS neighbor of the node is the DS node with the shortest communication distance of 2 hops away from the node, and the 3-hop DS neighbor of the node is the DS node with the shortest communication distance of 3 hops away from the node;

a DS node and a CS node form a connected dominating set;

a transceiver for receiving and transmitting data under the control of the processor;

according to the A-CS algorithm, selecting a gateway CS node for a 2-hop DS neighbor, and selecting according to the following rules:

DS node i reaches DS node m through relay node j, if (1) is satisfied

for the

wherein H ⁽²⁾ (i)＝N ⁽²⁾ (i)-N ⁽¹⁾ (i)；N ⁽²⁾ (i) Set of 2-hop neighbors for node i, N ⁽¹⁾ (i) A 1-hop neighbor set for node i;

denoted CS nodes elected for 2-hop DS neighbor nodes.

5. The node of claim 4, wherein the CS node is selected for a 3-hop DS neighbor node according to an A-CS algorithm, according to the following rules:

DS node i reaches DS node r through relay nodes j and m, if (1) is satisfied

Are all non-DS nodes, (2)i)<r, and (3)r ∈ H ⁽³⁾ (i) Then will be

for the

If the candidate CS node set CS ″) _ir 1 st hop node in

The CS node or the selected CS node according to the rule of selecting the gateway CS node for the 2-hop DS neighbor is the node xA 1 st hop CS node from the point i to the node r; if the CS node does not exist in the 1 st hop or the CS node is elected as the CS node according to the rule of selecting the gateway CS node for the 2-hop DS neighbor, the node o with the most occurrence times in the 1 st hop of the set CS' is elected as the 1 st hop of the CS node by the node i; if the times of occurrence of the node o and the node u are the same, selecting the node with high connectivity as the 1 st hop of the CS node; if the connectivity is the same, electing the node with the minimum ID as the 1 st hop of the CS node; the node i counts the occurrence frequency of the candidate 2 nd hop node m on the basis of the selected 1 st hop CS node, and selects the node q with the most occurrence frequency as the 2 nd hop of the CS node; if the times of occurrence of the node q and the node u are the same, selecting the node with high connectivity as the 2 nd hop of the CS node; if the connectivity is the same, electing the node with the minimum ID as the 2 nd hop of the CS node;

the communication domination set passes through the relay nodes j and m and reaches any one DS node of another DS node through 3 hops;

representing the CS nodes elected by the 3-hop DS neighbor nodes.

6. The node of claim 4, further comprising:

7. A gateway node selection apparatus, comprising:

the gateway selection module is used for selecting a CS node for a 3-hop DS neighbor node after selecting a gateway CS node for the 2-hop DS neighbor according to the connection information, wherein the 2-hop DS neighbor of the node refers to a DS node with the shortest communication distance of 2 hops from the node, and the 3-hop DS neighbor of the node refers to a DS node with the shortest communication distance of 3 hops from the node;

a connected dominating set forming module, which is used for forming a connected dominating set by the DS node and the CS node;

DS node i reaches DS node m through relay node j, if (1) is satisfied

for the

denoted CS nodes elected for 2-hop DS neighbor nodes.

8. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program for executing the method of any one of claims 1 to 3.