WO2017101575A1 - Wireless ad hoc network routing method and device - Google Patents

Abstract

Disclosed in the embodiments of the invention are a wireless ad hoc network routing method and device, relating to the field of LTE and wireless mobile ad hoc network, the method comprising: obtaining, by a current node, topology information of a fisheye field of the wireless ad hoc network where the current node is located, by interacting node information with other nodes; electing the nodes in the fisheye field as base station mode nodes or terminal mode nodes according to the obtained topology information of the fisheye field; generating a link status table according to the type of the current node and a one-hop neighboring node thereof; and generating, according to the link status table, a routing table with the current node serving as a root node. By means of the routing method and the device of the embodiments of the invention, the related LTE technology is enabled to be applied to the wireless ad hoc network, which better adapts to the rapid change of the network topology, improves the routing precision and saves the routing overhead.

Description

Method and device for routing wireless ad hoc network Technical field

The embodiments of the present invention relate to the fourth generation mobile communication (4G) Long Term Evolution (LTE) and the wireless mobile ad hoc network, and particularly to a wireless ad hoc network routing method and device. .

Background technique

Ad hoc network communication technology is a mobile communication technology that can be quickly and automatically networked. It is different from the general central, centralized control network that relies on pre-deployed communication infrastructure. It has rapid deployment and does not depend on basic communication facilities. It can be self-maintained and self-managing, and has strong anti-destructive characteristics. The nodes in the network not only have the functions of ordinary mobile terminals, but also have routing functions. The communication of the network relies on mutual cooperation, self-organization and self-operation between nodes, and mutual completion. Communication tasks; widely used in emergency communications.

At present, Ad hoc network communication technology is gradually developing towards high-speed, broadband and networked. It has evolved from the initial voice to data-based and digital-speaking, and the communication security model has also evolved from the traditional single-mode mode. The Internet model that combines multiple means. The traditional technology is no longer applicable. The LTE technology has the characteristics of high transmission rate, low wireless transmission delay, high spectrum efficiency, all-IP architecture, voice and data fusion, and meets the requirements of current tactical communication. Therefore, LTE technology is applied to the emergency. Communication is a new challenge and offers new opportunities for mobile communication devices.

Based on the above characteristics of Ad hoc network communication technology and LTE technology, the combination of Ad hoc network communication technology and LTE technology has become a technology development trend. How to route in the wireless ad hoc network based on LTE technology has become an urgent problem to be solved.

Summary of the invention

The purpose of the embodiments of the present invention is to provide a routing method and device for a wireless ad hoc network, which can better solve the routing through node mode election in a wireless ad hoc network based on the LTE communication mode. The problem.

According to an aspect of the embodiments of the present invention, a routing method of a wireless ad hoc network is provided, including:

The current node interacts with other nodes to obtain topology information of the fisheye domain of the wireless ad hoc network where the current node is located;

And selecting, according to the acquired topology information, a node in the fisheye domain as a base station mode node or a terminal mode node;

Establishing a corresponding adjacency relationship according to the type of the current node and its one-hop neighbor node, and obtaining link state information;

According to the link state information, the local node is used as a root node to generate a routing table.

Optionally, the step of the current node acquiring the topology information of the fisheye domain of the wireless ad hoc network in the current node by interacting with the node information of the other node includes:

The current node broadcasts a broadcast message carrying the information of the local node and the neighbor node information in the two hops to other nodes, and receives broadcast messages from other nodes;

Determining, according to the serial number of each broadcast message received, whether the broadcast message is the latest broadcast message;

If it is the latest broadcast message, the topology table is updated to obtain the topology information of the fisheye domain centered on the current node.

Optionally, the step of electing the node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information includes:

When it is determined that the current node's three hops and the neighbor nodes are all idle mode nodes according to the acquired topology information of the fisheye domain, it is determined whether the current node connection number is greater than the idle mode of the three hops or less. The number of connections to the node;

If it is determined that the number of connections of the current node is greater than the idle mode node of the three hops or less The number of connections, the current node is elected as a base station mode node;

If it is determined that the number of connections of the current node is equal to the number of connections of the idle mode node within three hops thereof, the node with the smallest node ID is elected as the base station mode node.

Optionally, the step of electing the node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information further includes:

When it is determined that the base node mode node exists in the three-hop and the neighbor node of the current node according to the acquired topology information of the fisheye domain, the current node is elected as the terminal mode node.

Optionally, the step of electing the node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information includes:

Determining, according to the acquired topology information of the fisheye domain, whether the number of connections of the current node is greater than the number of connections of the neighbor nodes within three hops or less;

If it is determined that the number of connections of the current node is greater than the number of connections of the neighbor nodes within three hops thereof, the current node is elected as a base station mode node;

If it is determined that the number of connections of the current node is equal to the number of connections of the neighbor nodes within three hops and less, the node with the smallest node ID is elected as the base station mode node.

Optionally, the step of electing the node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information further includes:

When it is determined that the base node mode node and the terminal mode node are present in the neighboring node of the current node according to the acquired topology information of the fisheye domain, determining whether the connection number of the current node is greater than the connection number of the terminal mode node;

If the number of connections of the current node is greater than the number of connections of the terminal mode node, the current node is elected as a base station mode node, otherwise the current node is elected as a terminal mode node.

Optionally, the step of electing the node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information further includes:

When the base station mode node exists in the neighbor node of the current node and the terminal mode node does not exist according to the acquired topology information of the fisheye domain, the current node is elected as the terminal mode node.

Optionally, the step of electing the node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information further includes:

When it is determined that the one-hop neighbor node of the current node is a terminal mode node according to the acquired topology information of the fisheye domain, or the base station module node does not exist in the one-hop neighbor node, and the base station module exists in the two-hop neighbor node, The current node is elected as a base station mode node.

Optionally, the step of establishing a corresponding adjacency relationship according to the type of the current node and its one-hop neighbor node, and obtaining link state information includes:

If the current node is a base station mode node, the current node establishes an adjacency relationship with the terminal mode node in the one-hop neighbor node, generates link state information corresponding to the adjacency relationship, and generates the generated link state. The information is carried in two different messages, which are sent to the nodes in the fisheye domain and the nodes outside the fisheye domain, so that the nodes in the fisheye domain and the fisheye domain update the link state information;

If the current node is a terminal mode node, the current node establishes an adjacency relationship with the base station mode node in the one-hop neighbor node, generates link state information corresponding to the adjacency relationship, and generates the generated link state. Information is sent to various nodes within the fisheye domain for each node within the fisheye domain to update link state information.

According to another aspect of an embodiment of the present invention, a routing apparatus for a wireless ad hoc network is provided, including the following modules disposed on each node:

The interaction module is configured to acquire topology information of the fisheye domain where the current node is located by interacting with the node information of the other node;

An election module, configured to set the fisheye domain according to the acquired topology information of the fisheye domain The node is elected as a base station mode node or a terminal mode node;

The link state generating module is configured to establish a corresponding adjacency relationship according to the type of the current node and one hop neighbor node, and obtain link state information;

The route generation module is configured to generate a routing table by using the local node as a root node according to the link state table.

In the embodiment of the present invention, a computer storage medium is further provided, and the computer storage medium may store an execution instruction, where the execution instruction is used to execute a routing method of the wireless ad hoc network in the foregoing embodiment.

Compared with related technologies, the beneficial effects of the embodiments of the present invention are:

The routing method and device of the embodiments of the present invention implement the related LTE technology applied to the wireless ad hoc network, which is more suitable for rapid change of the network topology, improves routing accuracy, and saves routing overhead.

DRAWINGS

1 is a schematic block diagram of a routing method of a wireless ad hoc network according to an embodiment of the present invention;

2 is a block diagram of a routing device of a wireless ad hoc network according to an embodiment of the present invention;

3 is a schematic diagram of basic steps of a routing protocol algorithm according to an embodiment of the present invention;

4 is a process diagram of periodically broadcasting node information according to an embodiment of the present invention;

FIG. 5 is a network topology diagram of a node initially powered on according to an embodiment of the present invention;

FIG. 6 is a network topology diagram of obtaining neighbor node information between nodes according to an embodiment of the present invention;

FIG. 7 is a topological diagram of forming an adjacency relationship after the node mode election is completed according to an embodiment of the present invention;

FIG. 8 is a flowchart of a general node mode election according to an embodiment of the present invention;

FIG. 9 is a flowchart of a preferred node mode election according to an embodiment of the present invention; FIG.

FIG. 10 is a topological diagram of a new node entering a network according to an embodiment of the present invention; FIG.

FIG. 11 is a topological diagram of the topology after the embodiment of the present invention is stabilized;

FIG. 12 is a diagram showing an adjacency relationship after an ordinary election algorithm is used in re-execution mode election according to an embodiment of the present invention;

FIG. 13 is a diagram showing an adjacency relationship after a preferred algorithm is used in re-execution mode election according to an embodiment of the present invention.

detailed description

The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

1 is a schematic block diagram of a method for routing a wireless ad hoc network according to an embodiment of the present invention. As shown in FIG. 1, the steps include:

Step S101: The current node acquires topology information of the fisheye domain of the wireless ad hoc network in which the current node is located by interacting with the node information.

For any node, when the node powers up and broadcasts the broadcast packet with the sequence number 1, the local information is only in the broadcast packet. When the node information is exchanged, the node may carry the information of the node and other node information in the fisheye domain that is acquired when the subsequent broadcast message is sent.

The fisheye domain may be an area within N hops (eg, 3 hops) centered on the node.

Step S102: Elect the node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information.

In the wireless ad hoc network, the topology information of the fisheye domain of each node may also change with the change of the network topology. Therefore, it is necessary to elect or re-elect the nodes in the fisheye domain according to different situations. For example, in the initial formation phase of the network, if the network in the fisheye domain converges, the node in the fisheye domain may be determined as a base station mode node (ie, the node working mode is the base station mode) or the terminal mode node (ie, the node working mode is the terminal mode). ), while in the network maintenance node, the number of node connections, etc. may cause re-election.

Step S103: Establish a corresponding adjacency relationship according to the type of the current node and its one-hop neighbor node, and obtain link state information.

If the step S102 determines that the current node is a base station mode node, establishing an adjacency relationship between the current node and the terminal mode node in the one-hop neighbor node, generating link state information corresponding to the adjacency relationship, and generating the generated chain The road state information is carried in two different messages, respectively, and sent to nodes in the fisheye domain and nodes outside the fisheye domain. For example, the link state information is carried in the broadcast packet and sent to the fisheye domain to update the link state information of each node in the fisheye domain. The link state information is carried in the link state packet and sent to the fisheye domain. Realize link state information update of nodes outside the fisheye domain.

If the step S102 determines that the current node is a terminal mode node, establishing an adjacency relationship between the current node and a base station mode node in the one-hop neighbor node, generating link state information corresponding to the adjacency relationship, and generating the The link state information is sent to each node in the fisheye domain for each node in the fisheye domain to update the link state information.

Step S104: Generate a routing table with the local node as a root node according to the link state table.

2 is a block diagram of a routing device of a wireless ad hoc network according to an embodiment of the present invention. As shown in FIG. 2, an interaction module, an election module, a link state generation module, and a route generation module are provided on each node.

The interaction module is configured to obtain topology information of the fisheye domain of the wireless ad hoc network in which the current node is located by interacting with the node information. When the fisheye domain is an area within N hops (for example, 3 hops) centered on the local node, taking 3 hops as an example, the topology information includes information of nodes within 3 hops and within.

The election module is configured to elect, according to the acquired topology information, a node in the fisheye domain as a base station mode node or a terminal mode node. When the link status changes, the election module can also re-elect according to the specific situation.

The link state generation module is configured to establish a corresponding adjacency relationship according to the type of the current node and its one-hop neighbor node, and obtain link state information. Each node can exchange link state information, so that each node can update its link state information in time to obtain a route to the destination node.

The route generation module is configured to generate a routing table with the local node as a root node according to the link state table.

When a node in a wireless ad hoc network uses LTE communication, the following features exist:

1) Due to the radio frequency blocking characteristic, the working mode of the appointment node is either the base station mode or the terminal mode.

2) When the network requires the node to work as the base station mode, the neighbor node operating as the terminal mode establishes a link with the node according to the link requirement.

3) The main role of the network is to forward data and communication between access nodes within the network, and the network formed is good.

4) When the working node as the terminal mode is used as a relay node, it is necessary to connect nodes operating in multiple base station modes.

5) The adjacency relationship is not established between the neighbor nodes working in the terminal mode. Only the neighboring nodes between the base station mode and the terminal mode have an adjacency relationship.

6) After the node in the base station mode does not work (ie, it is Down), the node mode is selected again.

7) Due to the variety and variability of the topology caused by network mobility, network state information and routing information must converge quickly.

Based on the characteristics of the LTE wireless communication method, it is necessary to perform mode election and maintenance on the node, and the terminal mode node can only directly communicate with the base station mode node, and the base station mode node and the base station mode node cannot directly communicate. Related wireless routing algorithms are mainly based on various evolutionary algorithms for route discovery or link-state exchange, and are only applicable to all neighbor nodes. It can communicate directly, that is, a wireless ad hoc network that is not restricted by the working mode of the node, and is not suitable for a wireless ad hoc network that is restricted by the working mode of the node, that is, not applicable to the wireless ad hoc network combined with the LTE technology. At the same time, the wireless ad hoc network that can communicate directly between all the neighboring nodes considers that the network mobility is insufficient, and there are too many routing control packets in the network, which wastes resources.

The invention improves the fisheye routing algorithm protocol based on the link state protocol by combining LTE wireless transmission characteristics and high-speed movement of nodes.

This embodiment is an improved routing protocol algorithm based on improved Fisheye State Routing (FSR). The area in the node 3 hop is set as the fisheye domain, and the area outside the 3 hops is set as the fisheye blurring domain. Each node in the 3 hops maintains the 3-hop topology information by periodically broadcasting the local node and the neighbor node information within 2 hops and within, and combines the maximum link number and the node ID to utilize the 3-hop topology information centered on the local node. Select the working mode of the node, and then form an adjacency relationship between the MANET Designated Router (MDR) node and the terminal mode node; in the 3 out-of-hop region, only the MDR (ie, the node in the base station mode) node can have a longer period. The broadcast mode flooding is performed on each node information, wherein the terminal mode node that establishes the adjacency relationship with only one base station mode node does not forward after receiving, and only the terminal mode node that establishes the adjacency relationship with the multiple base station mode nodes is received. Forward afterwards. Each node performs routing table generation and maintenance according to the maintained node link state table, and performs node mode maintenance according to the topology table in the three hops. It should be noted that the mode of the node is divided into a base station mode, a terminal mode, and an idle mode, where the node identity is not determined before the idle mode, for example, the terminal mode node checks the state of the MDR that it accesses according to the received broadcast message period. If the accessed MDR node is down or left, it first determines whether there is an MDR node that can be accessed according to the neighbor node information, and if it exists, directly accesses, if not, sets the terminal module node as an idle mode node. And wait for re-selection of the node mode; for example, the MDR node periodically checks the number of MDR neighbor nodes on the 2 hops, if the MDR node has 2 hop nodes (excluding the case where the network is originally a one-hop topology) and the number of MDR nodes becomes 0 , indicating that the one-hop network centered on this MDR node becomes an isolated network, and the MDR node is set as an idle mode node at this time, and waits for the node mode to be re-executed. s Choice.

FIG. 3 is a schematic diagram of basic steps of a routing protocol algorithm according to an embodiment of the present invention. As shown in FIG. 3, the steps include:

Step S201: Generating and maintaining network topology information.

After the node is powered on, the third-hop topology information centered on the local node is generated and maintained by periodically broadcasting the local node and the neighbor information within 2 hops and the broadcast packets of the neighbor node. The broadcast message is divided into a full broadcast and a differential broadcast, wherein the full broadcast periodically transmits all 2-hop two-way neighbors in a long period (three times the broadcast period of the different broadcast). The node information, the differential broadcast sends the changed neighbor node information in a short period, which can save bandwidth resources and timely understand the network topology changes. After receiving the broadcast packet from the other node, the node updates the topology table according to the sequence number and the packet information, and determines whether the topology information changes. After the topology information is changed, the node mode election step of step S202 can be performed after the topology is stable. .

In the network maintenance phase, after receiving the full broadcast message, the node determines whether it is the latest broadcast message according to the node number. If the sequence number is the latest, update the topology table of the 3-hop. After receiving the different broadcast message, the node updates the link state table. If the link status changes, update the routing table and perform node mode maintenance.

Step S202: node mode election and adjacency relationship formation and maintenance.

In the initial state, the node needs to wait until the acquired 3-hop network topology is stable, that is, after reaching convergence, the node mode is elected according to the topology information of the 3-hop network topology.

In the maintenance state, when the network topology changes within 3 hops and the node mode election is required again, the network topology is in a convergence state for a certain period of time, that is, after the topology is stable, the node mode is performed according to the topology information in the 3 hops. Elections.

The criteria for determining whether a node pattern needs to be re-elected are:

1. If the node is a node working in the terminal mode, the number of neighbor nodes of the node increases. When multiple MDR nodes connected to the local node are down, the node mode election is required.

2. If the node is a node operating in the base station mode, that is, the MDR node, when the number of neighbor nodes of the node is reduced to 1 or the number of adjacent relay nodes of the node is reduced to 0, the node mode election is required.

After the node identity is elected, the adjacency relationship is established according to the mode of the one-hop neighbor node, that is, after the working mode of the local node and the surrounding one-hop neighbor node is determined, the adjacency relationship is established, that is, the terminal mode node and the base station mode node are established. Link and generate their own link state tables.

Step S203: Link state information timing update processing.

For each node, the link state information in the three hops is updated and maintained by the broadcast information of the intra-3 hop node; the link state information of the hop node is received by the link state message broadcasted by the outer node of the hop 3 Update and maintenance, that is, when the link state message is received, the link state table is updated according to the sequence number, and if the link state changes, the routing table is updated in step S204.

Further, the base station mode node in the three hops also broadcasts the link state message to the node outside the three hops with a longer period of time, so that the node outside the three hops maintains the link state information.

Step S204: Generation and maintenance of a routing table.

The computing node is the root node, the path to each destination node is established according to the link state table, the routing table is updated, and the routing table is maintained. Preferably, the shortest path to each destination node is established using the Dijkstra algorithm according to the link state table.

The initial phase of the network topology and the network maintenance phase are described in detail below with reference to the accompanying drawings.

First, the network topology is initially formed when the steps are implemented:

Step 1: Formation of the network topology.

After the node is powered on and initialized, the periodic broadcast timer is started. The timer duration is Δt. When the timer expires, the device sends a differential broadcast packet with the sequence number of the packet. The packet contains only the information of the node. Neighbor node information, when the timer times out is 3n△t At the time (n=1, 2, 3...), the full broadcast message is sent, as shown in the process diagram of the periodic broadcast node information shown in FIG. 4, and the message sequence number is incremented by 1 each time the node sends the broadcast message.

After receiving the broadcast packet from the neighboring node, the node processes the broadcast packet according to the sequence number and packet type. Specifically, after receiving the full broadcast broadcast message, the node determines whether it is the latest broadcast message according to the node serial number. If the serial number is the latest, the node updates the 3-hop internal topology table and carries the topology when the broadcast message is sent next time. Neighbor node information in the table; after receiving the distinct broadcast message, the node updates the link state table, but does not update the routing table.

FIG. 5 is a network topology diagram of a node initially powered on according to an embodiment of the present invention. As shown in FIG. 5, this example only describes a scenario where a node is powered on:

In the initial state of the network, node 1, node 2, node 3, and node 4 are powered on at the same time. At the beginning, each node has no neighboring nodes. Each node carries its own node information when it sends the corresponding hello broadcast message for the first time. There is no adjacency between the nodes. For example, after node 1 receives the broadcast message sent by node 2 for the first time, node 1 updates the topology table as shown in Table 1.

Table 1

	Node 1	Node 2
Node 1		0
Node 2	0

After node 1 receives the broadcast message of node 3, node 1 updates the topology table as shown in Table 2.

Table 2

	Node 1	Node 2	Node 3
Node 1		0	0
Node 2	0		0
Node 3	0	0

During the period, the node 2 receives the broadcast packet sent by the node 1 and the node 3 for the first time, and the updated topology table is as shown in Table 3.

table 3

	Node 1	Node 2	Node 3
Node 1		0	0
Node 2	0		0
Node 3	0	0

The node 3 receives the broadcast packets of the node 1, the node 2, and the node 4, respectively. The updated topology table is shown in Table 4.

Table 4

Node 4 receives the broadcast packet of node 3, and the updated topology table is as shown in Table 5.

table 5

The second period expires, and the node 1 sends a broadcast message carrying the information of the node and the information of the neighbor node 2 and the neighbor node 3, and the message sequence number is 2.

After receiving the broadcast packet of the node 1, the node 2 finds that there is a node in the node 1, and updates the neighbor relationship between the node and the node 1 as a two-way neighbor, and updates the topology table of the node, as shown in Table 6.

Table 6

	Node 1	Node 2	Node 3
Node 1		1	0
Node 2	1		0
Node 3	0	0

After receiving the broadcast packet of the node 3, the node 2 updates the topology table of the node as shown in Table 7.

Table 7

	Node 1	Node 2	Node 3	Node 4
Node 1		1	0	0
Node 2	1		1	0
Node 3	0	1		0
Node 4	0	0	0

After receiving the broadcast packet of the node 2, the node 1 finds that there are new neighbor nodes 4 and 3 and itself in the node 2, and the update topology table is as shown in Table 8.

Table 8

	Node 1	Node 2	Node 3	Node 4
Node 1		1	0	0
Node 2	1		0	0
Node 3	0	0		0
Node 4	0	0	0

During the period, the node 3 receives the broadcast packets of the nodes 1, 2, and 4, and the update topology table is as shown in Table 9.

Table 9

	Node 1	Node 2	Node 3	Node 4
Node 1		0	1	0
Node 2	0		1	0
Node 3	1	1		1
Node 4	0	0	1

During the period, the node 4 receives the broadcast message of the node 3, and updates the topology table as shown in Table 10.

Table 10

	Node 1	Node 2	Node 3	Node 4
Node 1		0	0	0
Node 2	0		0	0
Node 3	0	0		1
Node 4	0	0	1

After the third period timesout broadcast message, the topology table of each node is shown in Table 11.

Table 11

	Node 1	Node 2	Node 3	Node 4
Node 1		1	1	0
Node 2	1		1	0
Node 3	1	1		1
Node 4	0	0	1

Among them, 1 in each table represents a two-way neighbor relationship, and 0 represents a non-neighbor relationship.

Then, after four consecutive cycles, that is, 4 Δt, the topology remains unchanged, indicating that the topology convergence topology is stable, and the topology map is as shown in FIG. 6 after the neighbor node information is acquired between the nodes.

Step 2: Node mode election and adjacency formation.

After the network topology is stable, the node mode is elected and the adjacency is established, and a topology diagram is formed to form an adjacency relationship after the node mode election is completed as shown in FIG. 7. It should be noted that the criterion for network topology convergence is that the network topology does not change within a certain time 4 Δt.

FIG. 8 is a flowchart of a general node mode election according to an embodiment of the present invention. As shown in FIG. 8, the steps include:

Step S301: The election timer expires.

Step S302: Determine whether there is a neighbor node in the local node. If yes, go to step S303. Otherwise, go to step S307.

Step S303: It is determined whether the 3-hop and the intra-neighbor node of the local node are all in the idle mode. If all the idle modes are in the idle mode, step S308 is performed; otherwise, step S304 is performed.

Step S304: It is determined whether the node has a neighbor node in the base station mode. If yes, step S310 is performed, otherwise step S305 is performed.

Step S305: It is determined whether the neighboring nodes are all in the terminal mode. If they are all in the terminal mode, step S309 is performed, otherwise step S306 is performed.

Step S306: determining whether there is a base station mode node in the two hops, if yes, performing steps S309, otherwise step S307 is performed.

Step S307: The election timer is started, and the timing duration is Δt.

Step S308: determining whether the node has the largest number of connections in the nodes with 3 hops or less and the node ID is the smallest. If yes, step S309 is performed, otherwise step S307 is performed.

Step S309: Set the working mode of the local node to the base station mode, that is, the identity of the local node is a base station mode node.

Step S310: Set the working mode of the local node to the terminal mode, that is, the identity of the local node is the terminal mode node, and step S311 is performed.

Step S311: It is determined whether the working modes of the neighboring nodes of the local node are all determined. If yes, step S312 is performed, otherwise step S307 is performed.

Step S312: Adjacency relationship is established between the base station mode node and the terminal mode node, and a link is established, and the two nodes respectively establish and update a link state table.

Step S313: End the flow.

Through the process, it can be seen that the ordinary election process is:

1) If there is no neighbor node in the node, the working mode of the node is set to idle mode, and the election timer is set, the duration is Δt, waiting for the next cycle election.

2) If the three hops and the neighbors of the node are all idle mode, the number of connections of the node is the largest among all the nodes with idle mode within 3 hops, and the working mode of the node is selected as the base station mode, and the number of connections is When there are equal cases, the node with the small node ID is selected as the base station mode node; otherwise, the election timer is set, and the election is waited for the next cycle.

3) If the node has a neighbor node in the base station mode, the node is set as a terminal mode node.

4) If the one-hop neighbor node of the node has only the terminal mode, the node is set as the base station mode node and is the MDR node.

5) If the node in the base station mode does not exist in one hop of the node, and the node in the base station mode exists in the 2-hop neighbor, the node is set as the base station mode node.

6) If the one-hop neighbor node mode and the local node mode of the node have been determined, the adjacency relationship is established, and the terminal mode node selects the node whose neighbor is the base station mode to initiate connection establishment; otherwise, the election timer is set, waiting for the next cycle. Make the connection established.

FIG. 9 is a flowchart of a preferred node mode election according to an embodiment of the present invention. As shown in FIG. 9, the steps include:

Step S401: The election timer expires.

Step S402: Determine whether there is a neighbor node in the local node. If yes, go to step S403. Otherwise, go to step S408.

Step S403: determining whether the node has the largest number of connections in the node of 3 hops or less and the node ID is the smallest. If yes, step S413 is performed, otherwise step S404 is performed.

Step S404: It is determined whether the node has a neighbor node in the base station mode and a neighbor node in the terminal mode. If yes, step S409 is performed, otherwise step S405 is performed.

Step S405: It is determined whether the neighbor nodes are all in the base station mode or the base station and the non-terminal mode. If yes, step S410 is performed, otherwise step S406 is performed.

Step S406: It is determined whether the neighbor nodes are all in the terminal mode. If yes, step S413 is performed, otherwise step S407 is performed.

Step S407: It is determined whether there is a base station mode node in the 2-hop neighbor node of the local node, if yes, step S413 is performed, otherwise step S408 is performed.

Step S408: The election timer is started, and the timing duration is Δt.

Step S409: It is determined whether the number of connections of the local node is greater than the number of connections of the neighboring nodes in the terminal mode. If yes, step S413 is performed, otherwise step S410 is performed.

Step S410: setting the working mode of the node to the terminal mode, that is, the identity of the node is the end. End mode node, and step S411 is performed.

Step S411: It is determined whether the working modes of the neighboring nodes of the local node are all determined. If yes, step S412 is performed, otherwise step S408 is performed.

Step S412: Adjacency relationship is established between the base station mode node and the terminal mode node, and a link is established, and the two nodes respectively establish and update a link state table.

Step S413: Set the working mode of the node to the base station mode.

Step S414: End the flow.

As can be seen from the process, the preferred election process is:

1) If there is no neighbor node in the node, the working mode of the node is set to idle mode, and the election timer is set, the duration is Δt, waiting for the next cycle election.

2) If the number of connections of the node is the largest among all the nodes with 3 hops or less, the node is selected as the base station mode node, and when there are equal numbers of connections, the node with the small node ID is selected as the base station mode node.

3) If the node has a neighbor node in the base station mode and a neighbor node in the terminal mode, and the number of connections of the local node is greater than the number of connections of the neighbor node in the terminal mode, the local node is set to the base station mode, otherwise the local node is set to the terminal mode.

4) If the node only has a neighbor node in the base station mode or a neighbor node in the base station mode and the non-terminal mode, the node is set to the terminal mode.

5) If the one-hop neighbor node of the node has only the terminal mode, the node is set as the base station mode node and is the MDR node.

6) If there is no node in the base station mode in one hop of the node, and a node in the base station mode exists in the 2-hop neighbor, the node is set as the base station mode node.

7) If the one-hop neighbor node mode and the local node mode of the node have been determined, the adjacency relationship is established, and the terminal mode node selects the neighbor as the base station mode node to initiate connection establishment. Set, otherwise set the election timer, wait for the next cycle to establish the connection.

Following the example of step 1, the topology in the network has been stabilized, and the node mode election is started. Node 1, Node 2, and Node 4 find that the connectivity of the local node is not the largest in the three hops. After the next cycle election, node 3 finds its own. The connection degree is the largest, and the node is set to the base station mode; after the next period expires, the nodes 1, 2, and 4 respectively set themselves to the terminal mode; and the nodes 1, 2, 4 initiate the connection with the node 3 to establish the adjacency. Relationship, as shown in Figure 7.

Step 3: Link state timing update processing.

The 3 hops belong to the fisheye domain, and the 3 hops belong to the fisheye fuzzy domain. The link state in the 3 hops is updated periodically by the different broadcast message, and the node periodically sends the link state update (LSU) to the 3 hops. Message.

The 3-hop internal node mode election is completed and the adjacency relationship is established. If the local node is in the base station mode, the link state update message is sent out to the 3 hops, and the link state update timer is set, and the duration is k (k>3 Δt). After receiving the packet, the terminal mode node with the relay function determines whether the packet is the latest packet according to the sequence number in the packet. If the packet is the latest packet, the packet is forwarded. Otherwise, the packet is discarded.

Further, after receiving the link state update message, the node determines that the sequence number is the latest, updates the link state table, and determines whether the link state changes. If there is a change, the routing table is updated.

Following the example of step 1, the adjacency relationship after the link state update is as shown in Table 12.

Table 12

	Node 1	Node 2	Node 3	Node 4
Node 1		0	1	0
Node 2	0		1	0
Node 3	1	1		1
Node 4	0	0	1

Step 4: Formation of a routing table.

According to the link state table, the root node of the node is used to generate a routing table of the shortest path tree according to the Dijkstra algorithm. The routing table information includes information such as a destination node, a next hop node, and a hop count.

Second, the specific implementation steps of the network maintenance phase

Step 10: Network topology update and maintenance.

The node maintains the topology information and link state information in the three hops by periodically broadcasting the local node and the information of the neighbor nodes within 2 hops and within the hops, and receiving the broadcast packets from other nodes. The timer duration is Δt, when the timer expires. After that, a differential broadcast message is sent. When the timer timeout period is 3n Δt (n=1, 2, 3...), a full broadcast message is sent, as shown in FIG. 4 .

After receiving the full broadcast broadcast message, the node determines whether it is the latest broadcast message according to the node serial number. If the sequence number is the latest, the topology table in the 3-hop is updated, and the link status is updated after receiving the different broadcast message. table.

Here, a scenario in which a node is added to cause a topology change is listed, and the present invention is not limited to this scenario:

FIG. 10 is a topological diagram of a new node entering a network according to an embodiment of the present invention. As shown in FIG. 10, node 5 and node 6 are powered on. At the beginning, nodes 5 and 6 have no neighbor information and only broadcast their own node information. After 4 Δt time, the topology table of each node is stable. As shown in Figure 11, the topology is stable. The topology table is shown in Table 13. Show.

Table 13

	Node 1	Node 2	Node 3	Node 4	Node 5	Node 6
Node 1		0	1	0	0	0
Node 2	0		1	0	1	1
Node 3	1	1		1	0	0
Node 4	0	0	1		0	0
Node 5	0	1	0	0		0
Node 6	0	1	0	0	0

Step 20: Maintain the node mode and the adjacency relationship.

When the network topology changes, the criteria for determining whether to re-select the node mode are as follows:

1. If the node is a node working in the terminal mode, when the number of neighbor nodes of the node increases or all MDR nodes connected to the node are down, the node mode election needs to be performed again.

2. If the node is an MDR node, that is, a node operating in the base station mode, if the number of neighbor nodes of the node is reduced to less than or equal to 1 or the number of adjacent relay nodes of the node is reduced to 0, the node mode election needs to be performed again. .

The election process of the node mode election and the adjacency relationship is the same as the initial state (that is, when the network topology is initially formed), and will not be described here.

Following the example in step 10, node 2 needs to re-execute the node mode election according to whether the network topology changes the criteria for whether the node is re-elected.

FIG. 12 is a diagram showing adjacency relationship after a normal election algorithm is used in re-execution mode election according to an embodiment of the present invention. As shown in FIG. 12, according to a common node election mode, a node 2 neighbor has a base station mode node, so Still in the terminal mode, the neighbor node of node 5 has only the terminal mode, so node 5 is the base station mode; the neighbor node of node 6 has only the terminal mode, so node 6 is the base station mode. After the mode election is completed, node 2 initiates the establishment of an adjacency relationship to node 5 and node 6.

FIG. 13 is a diagram showing adjacency relationship after a preferred algorithm is used in re-execution mode election according to an embodiment of the present invention. As shown in FIG. 13, the connection degree of node 2 is larger than that of node 1 according to a preferred node election mode. It is the base station mode, and the neighbor of node 5 has only the base station mode, and selects itself as the terminal mode. After the node mode is elected, the broadcast message node 1 discovers that its neighbor node 2 mode is changed to the base station mode, and then initiates the establishment of the connection to the node 2, and the node 5 initiates the establishment of the adjacency relationship to the node 2.

Step 30: Link state timing update processing.

The processing mechanism is the same as step 3 in the initial state (ie, when the network topology is initially formed).

Step 40: Routing table update and maintenance.

Update the routing table in the following three cases:

1) When the link status changes

When the link state message is changed according to the received link state message or the neighbor link state is changed, the link state table is updated, and the routing table is updated according to the latest link state table.

2) Received unreachable message

When an unreachable packet is received, the route to this destination is deleted according to the destination IP address.

3) When data forwarding does not exist to the destination route

When the data is forwarded to find the destination route, the route request message (Route Request, RREQ) is sent to the MDR or the relay node with the adjacency relationship when the route does not exist and the destination node is not in the 3-hop topology of the node. Start the timer, receive the MDR or relay node of the RREQ message, and after confirming that it is the latest RREQ message to the destination node according to the sequence number, record the reverse route to the source node and check whether it has the route to the destination IP address. If yes, the route response message (Route Response, RREP) packet is sent to the source node according to the original path. If the path to the destination node is unreachable, the node discards the packet, otherwise the reverse route clearing timing is started. If the timer expires before receiving the RREP response packet, the intermediate node clears the reverse route. If the RREP packet is received before the timeout, the forward route to the destination node is established and updated. Routing table; if the source node receives the RREP packet before the timer expires, it updates the routing table and sends the packet; if the timer does not receive any response after the timer expires Packets, discards the data, and send the source packet unreachable object.

In summary, the present invention has the following technical effects:

1. The present invention applies the related LTE technology to a wireless ad hoc network, which improves the communication rate and quality, and the data service can also be well applied;

2. In the broadcast link state message, only the node having the adjacency relationship forwards the packet, which saves routing overhead.

The invention combines the protocol of the on-demand route discovery with the link state protocol, saves the overhead of the routing control packet, saves the bandwidth, adapts to the rapid change of the network topology, and improves the routing precision. Accuracy can effectively reduce the packet loss rate of packets;

4. The present invention is applicable to a wireless ad hoc network employing peer-to-peer or layered methods.

Embodiments of the present invention also provide a storage medium. Optionally, in the embodiment, the foregoing storage medium may be configured to store program code for performing the following steps:

S1, the current node obtains topology information of the fisheye domain of the wireless ad hoc network in which the current node is located by interacting with the node information of the other node;

S2, the current node obtains topology information of the fisheye domain of the wireless ad hoc network in which the current node is located by interacting with the node information of the other node;

S3. Establish a corresponding adjacency relationship according to the type of the current node and its one-hop neighbor node, and obtain link state information.

S4: Generate a routing table by using the local node as a root node according to the link state information.

Optionally, the storage medium is further arranged to store program code for performing the following steps:

S1. The current node broadcasts a broadcast message carrying the information of the local node and the neighbor node information in the two hops to other nodes, and receives broadcast messages from other nodes.

S2. Determine, according to the sequence number of each broadcast packet received, whether the broadcast packet is the latest broadcast packet.

S3: If it is the latest broadcast message, update the topology table to obtain topology information of the fisheye domain centered on the current node.

Optionally, in this embodiment, the foregoing storage medium may include, but not limited to, a USB flash drive, a Read-Only Memory (ROM), a Random Access Memory (RAM), a mobile hard disk, and a magnetic memory. A variety of media that can store program code, such as a disc or a disc.

For example, the specific examples in this embodiment may refer to the examples described in the foregoing embodiments and the optional embodiments, and details are not described herein again.

Although the invention has been described in detail above, the invention is not limited thereto, and various modifications may be made by those skilled in the art in accordance with the principles of the invention. Therefore, modifications made in accordance with the principles of the invention are to be understood as falling within the scope of the invention.

Industrial applicability

In the embodiment of the present invention, the related LTE technology is applied to the wireless ad hoc network, which is more suitable for rapid change of the network topology, improves routing accuracy, and saves routing overhead.

Claims (10)

1. A routing method for a wireless ad hoc network includes:

   The current node interacts with other nodes to obtain topology information of the fisheye domain of the wireless ad hoc network where the current node is located;

   And selecting, according to the acquired topology information, a node in the fisheye domain as a base station mode node or a terminal mode node;

   Establishing a corresponding adjacency relationship according to the type of the current node and its one-hop neighbor node, and obtaining link state information;

   According to the link state information, the local node is used as a root node to generate a routing table.
2. The method according to claim 1, wherein the step of the current node acquiring the topology information of the fisheye domain of the wireless ad hoc network in the current node by interacting with the node information of the other node includes:

   The current node broadcasts a broadcast message carrying the information of the local node and the neighbor node information in the two hops to other nodes, and receives broadcast messages from other nodes;

   Determining, according to the serial number of each broadcast message received, whether the broadcast message is the latest broadcast message;

   If it is the latest broadcast message, the topology table is updated to obtain the topology information of the fisheye domain centered on the current node.
3. The method according to claim 1, wherein the step of electing a node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information comprises:

   When it is determined that the current node's three hops and the neighbor nodes are all idle mode nodes according to the acquired topology information of the fisheye domain, determining that the current node connection number is No greater than the number of connections in idle mode nodes within three hops or less;

   If it is determined that the number of connections of the current node is greater than the number of connections of the idle mode node within three hops or less, the current node is elected as a base station mode node;

   If it is determined that the number of connections of the current node is equal to the number of connections of the idle mode node within three hops thereof, the node with the smallest node ID is elected as the base station mode node.
4. The method of claim 3, wherein the step of electing the node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information further comprises:

   When it is determined that the base node mode node exists in the three-hop and the neighbor node of the current node according to the acquired topology information of the fisheye domain, the current node is elected as the terminal mode node.
5. The method according to claim 1, wherein the step of electing a node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information comprises:

   Determining, according to the acquired topology information of the fisheye domain, whether the number of connections of the current node is greater than the number of connections of the neighbor nodes within three hops or less;

   If it is determined that the number of connections of the current node is greater than the number of connections of the neighbor nodes within three hops thereof, the current node is elected as a base station mode node;

   If it is determined that the number of connections of the current node is equal to the number of connections of the neighbor nodes within three hops and less, the node with the smallest node ID is elected as the base station mode node.
6. The method according to claim 5, wherein the step of electing a node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information further comprises:

   When it is determined that the base node mode node and the terminal mode node are present in the neighboring node of the current node according to the acquired topology information of the fisheye domain, determining whether the connection number of the current node is greater than the connection number of the terminal mode node;

   If the number of connections of the current node is greater than the number of connections of the terminal mode node, the current node is elected as a base station mode node, otherwise the current node is elected as a terminal mode node.
7. The method according to claim 6, wherein the step of electing the node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information further comprises:

   When the base station mode node exists in the neighbor node of the current node and the terminal mode node does not exist according to the acquired topology information of the fisheye domain, the current node is elected as the terminal mode node.
8. The method according to claim 4 or 7, wherein the step of electing a node in the fisheye domain as a base station mode node or a terminal mode node according to the acquired topology information further comprises:

   When it is determined that the one-hop neighbor node of the current node is a terminal mode node according to the acquired topology information of the fisheye domain, or the base station module node does not exist in the one-hop neighbor node, and the base station module exists in the two-hop neighbor node, The current node is elected as a base station mode node.
9. The method according to claim 8, wherein the step of establishing a corresponding adjacency relationship according to the type of the current node and its one-hop neighbor node, and obtaining link state information includes:

   If the current node is a base station mode node, the current node establishes an adjacency relationship with the terminal mode node in the one-hop neighbor node, and generates a chain corresponding to the adjacency relationship. The road state information, and the generated link state information is carried in two different messages, which are respectively sent to the nodes in the fisheye domain and the nodes outside the fisheye domain, so as to be updated by the nodes in the fisheye domain and the fisheye domain. Link status information;

   If the current node is a terminal mode node, the current node establishes an adjacency relationship with the base station mode node in the one-hop neighbor node, generates link state information corresponding to the adjacency relationship, and generates the generated link state. Information is sent to various nodes within the fisheye domain for each node within the fisheye domain to update link state information.
10. A routing device for a wireless ad hoc network, comprising the following modules disposed on each node:

    The interaction module is configured to acquire topology information of the fisheye domain of the wireless ad hoc network in which the current node is located by interacting with the node information of the other node;

    An election module is configured to elect, according to the acquired topology information, a node in the fisheye domain as a base station mode node or a terminal mode node;

    The link state generating module is configured to establish a corresponding adjacency relationship according to the type of the current node and one hop neighbor node, and obtain link state information;

    The route generation module is configured to generate a routing table by using the local node as a root node according to the link state table.

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