KR102038882B1 - Method and apparatus for enhancing reliability transmission through adjacent node transmission on decentralized network using tree topology - Google Patents

Abstract

The present invention relates to a method and apparatus for improving transmission reliability through transmission of adjacent nodes in a distributed network using a tree topology. Sending messages improves the reliability of end-to-end message transmission.

Description

METHOD AND APPARATUS FOR ENHANCING RELIABILITY TRANSMISSION THROUGH ADJACENT NODE TRANSMISSION ON DECENTRALIZED NETWORK USING TREE TOPOLOGY}

The present invention relates to a technique for improving the transmission reliability of a message.

In the tree topology, all messages are transmitted from the child terminal to the parent terminal. If the transmission fails to the parent terminal or if the parent terminal fails to relay, it may be necessary to perform end-to-end retransmission or fail if there is no retransmission.

The Internet of Thing (IoT) is a technology that adds the Internet function to the sensor to automatically execute pre-input commands or commands sent remotely over the Internet by the user. It is applied to. In the early days, the Internet of Things was mainly connected to the Internet by wire, but as the number increases, the IoT is forming a sensor network connected wirelessly around a gateway connected to the Internet, and the sensor terminal is evolving to communicate with a user through a gateway. Even though the sensor terminal is connected to a power source at a fixed location, the network configuration may change due to a change to an indoor communication environment such as a door opening and closing. In particular, when the sensor terminal is used in an industrial or outdoor environment, the change may occur more frequently, which may result in loss of information. This loss of information may cause a malfunction of the sensor terminal, so a method for overcoming this is necessary.

WO2014-104454 discloses an intermediate node having a minimum distance cost and interference cost in a routing system in a source node for transmitting a packet, a destination node for receiving a packet, and a plurality of intermediate nodes located between the source node and the destination node. Is the way to choose. There are some limitations in detecting and rerouting packets continuously when packets are lost due to indoor environment changes such as separation of doors and signal quality due to movement of features.

Referring to FIG. 1, a diagram illustrating transmission in a conventional tree topology, in which a sensor node (SN) is a node for transmitting sensing information, a gateway node (GN) is a node for receiving sensing information transmitted by the SN, and a solid line is a topology The link consists of a dotted line, which is not composed of a topology, but represents a link capable of communication. In order to transmit information to the GN, the SN3 transfers the information to SN3-> SN1-> GN. In scenarios where SN3-> SN1 is success and SN1-> GN is failure, the existing solution is for SN1 to find and route to another path (Local Recovery), in which case the skill of performing SN1-> SN2 link request process is required. In addition, there is a problem that an additional delay occurs due to the link connection process. Alternatively, there may be a solution to notify SN3 of the transmission failure and that SN3 discovers another link, in which case the SN3 needs to store a packet that has completed transmission, and if the GN receives it indicates that end-to-end transmission is complete. There is a problem in that there is a need for a technique to inform the user, a need for additional memory, and resource usage due to ACK information transmission.

WO 2014-104454

An object of the present invention is to improve the reliability of end-to-end message transmission by transmitting a message through a neighboring terminal connected with a transmitting terminal when the transmission to the parent terminal fails or the parent terminal fails to relay.

In wireless sensor networks in the form of a tree topology, temporary signal deterioration due to indoor door opening and movement of features in mountainous terrain can reduce the reliability of information transmission. In addition, network disconnection may occur by performing a path resetting process for recovering a disconnected path. In order to overcome this problem, if a multipath is set and information is transmitted through the multipath, the reliability of the network can be improved, but there is a problem of consuming radio resources. According to various embodiments of the present disclosure, in a wireless sensor network system configured in a tree topology, even when a temporary decrease in signal quality occurs, transmission failure information is transmitted by using available alternative paths, thereby transmitting reliability of the sensor network. It can provide a method and apparatus that can improve the. In addition, it is possible to provide a method and apparatus for reducing a re-establishment delay based on this.

In the present invention, referring to FIG. 2, when a transmitting node transmits information to a receiving node by using a multihop transmission method, when end-to-end information transmission fails, a node that fails to transmit exists when a neighbor node exists. In this case, the information is transmitted to one terminal of a neighbor node, and when the transmission is successful, the neighbor node is changed to a parent node, thereby improving reliability of end-to-end information transmission and improving the speed of the path change.

Preferably, when the end-to-end information transmission fails, if there is no neighbor node of the node that failed to transmit, retransmit to the node that previously transmitted the information, and the node that has transmitted the information received The method transmits the information to one of the neighboring nodes, and if the transmission is successful, changes the neighboring node to a parent node, thereby improving reliability of information transmission between species and improving the speed of the path change.

In addition, in order to solve the above technical problem, an embodiment of the present invention provides an information transmission method of a network including N nodes in a tree topology. When the transmission of the predetermined information to the second node fails, the first node that fails to transmit searches for a neighboring node of the second node; ii) when the neighboring node of the second node exists; A node transmitting the predetermined information to a neighbor node of the second node, iii) a neighbor node of the second node transmitting the predetermined information to the second node. And iv) the second node provides a method for transmitting information in a network configured in a tree topology including forwarding the predetermined information to a destination.

In one embodiment of the present invention, when the first node that has received the predetermined information fails to transmit the predetermined information to the second node, the first node transmits the predetermined information to the second node. The second node may not receive the predetermined information even after trying a predetermined number of times.

In an embodiment of the present invention, the network configured in the tree topology includes a transmitting node, a receiving node, a parent node of a transmitting node, a neighbor node of a transmitting node, a parent node of a receiving node, and a neighbor node of a receiving node. In step ii), when the first node transmits the predetermined information to a neighbor node of the second node and the transmission is successful, the first node sets the neighbor node of the second node as a parent node. The method may further include setting itself as a child node of the neighbor node of the second node.

In one embodiment of the present invention, the step ii), if there is no neighbor node of the second node, the first node retransmits the predetermined information to the node that has transmitted the information to itself, and received The node may further include the step of transmitting the received information to its neighbor node, but if the transmission is successful, setting the neighbor node as a parent node and setting itself as a child node of the neighbor node.

In one embodiment of the present invention, the neighboring node transmits the predetermined information to a third node other than the first node and the second node to cause the third node to perform steps i), ii), iii), and iv).

In one embodiment of the present invention, the step iv), wherein the second node becomes another first node and transfers the predetermined information to another second node according to the steps i), ii) and iii). It may include the step of transmitting the predetermined information to the destination including a plurality of transmission procedures.

In one embodiment of the present invention, the predetermined information may be configured in the form of a tree topology characterized in that it has a beacon (beacon) message form.

As described above, the present invention has the effect of improving the reliability of message transmission. In a distributed network system configured in a tree topology, in transmitting data from a transmitting terminal to a receiving terminal, not only the terminal located on the transmission path but also the neighboring terminal of the terminal located on the transmission path or the neighboring terminal of the receiving terminal The reliability of the transmission can be improved.

In addition, the signal quality between at least one of the transmitting terminal, the receiving terminal, and the terminal located on the transmission path may be reduced, thereby reducing the time required to recognize that the path is disconnected.

In addition, by maintaining the neighbor terminal information in the route table, it is possible to generate the always-by-pass route, it is possible to reduce the communication disconnection that can occur during the recovery of the disconnected route.

1 is a diagram illustrating transmission in a conventional tree topology.
2 is a diagram for describing a method of improving transmission reliability through transmission of adjacent nodes in a distributed network using a tree topology according to an exemplary embodiment of the present invention.
3 is a diagram illustrating a configuration of a communication apparatus according to an embodiment.
4 is a diagram illustrating a tree structure network configuration according to an exemplary embodiment.
5 is a flowchart illustrating a method of guaranteeing reliability according to an embodiment.
6 is a diagram illustrating a routing table according to an embodiment.
7 is a diagram illustrating a data transmission procedure for guaranteeing reliability according to an embodiment.
8 to 11 are diagrams illustrating a transmission procedure according to an embodiment.
12 is a flowchart illustrating a procedure of an information transmission method of a network configured in a tree topology according to an embodiment of the present invention.

Advantages and features of the present invention, and a method of achieving them will be apparent from the following detailed description with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the technical field to which the present invention belongs. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout. “And / or” includes each and all combinations of one or more of the items mentioned.

Although the first, second, etc. are used to describe various elements, components and / or sections, these elements, components and / or sections are of course not limited by these terms. These terms are only used to distinguish one element, component or section from another element, component or section. Therefore, the first device, the first component, or the first section mentioned below may be a second device, a second component, or a second section within the technical spirit of the present invention.

In addition, in each step, an identification code (eg, a, b, c, etc.) is used for convenience of description, and the identification code does not describe the order of the steps, and each step is clearly specified in context. Unless stated in order, it may occur differently from the stated order. That is, each step may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprises” and / or “comprising” refers to the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. In addition, the terms defined in the commonly used dictionaries are not ideally or excessively interpreted unless they are specifically defined clearly.

In describing the embodiments of the present invention, when it is determined that a detailed description of a known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the embodiments of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the contents throughout the specification.

Referring to FIG. 3, as a configuration diagram of a communication device, the sensed information is received as an I / O IF, then transferred to a communication IF through a common bus, and transmitted to the gateway through the communication device. Preferably, the gateway receives the information through the communication IF, and then transfers the information to the memory through the common bus to collect and manage the sensing information generated by other communication devices, wherein the processor is higher than the received information. It performs the processing work delivered to the layer, and Memory consists of application program, API, middleware, and kernel stage.

Referring to FIG. 4, as a tree structure network, preferably, the GW may transmit a beacon to connect one hop link. More specifically, the SNs in the first hop (SN1, SN2, SN5, SN4) receives the Beacon sent by the GW, requests the GW to be assigned to the Beacon to be used by the GW, and the GW receives the SN requesting the Beacon. SNs registered as CNs (Child Nodes) and Beacon assigned GWs are registered as Parent Nodes. Here, the Parent Node means an upper node of the own link. For example, since the upper node of SN8 is SN7, the Parent Node of SN8 is SN7.

Preferably, repeat this process until all SNs have been assigned a Beacon, and if the SN receives a Beacon from a number of other SNs in the linking procedure (e.g. Beacon can be received from SN4), and the SN that satisfies the condition (condition is out of range) can be registered as its parent.

Specifically, SN3 may receive a beacon from SN2 and SN4, SN4 satisfying the condition may be registered as a parent node of SN3, and the remaining node SN2 may be registered as a neighbor node of SN3. Here, since SN3 compares the path costs of SN2 and SN4, since SN4 has a lower path cost, SN3 may be registered as a parent node and SN3 may be registered as a neighbor node.

In addition, in the drawing illustrated in FIG. 4, neighboring nodes, that is, nodes connected by a dotted line, correspond to neighboring nodes. The neighbor node may include a node other than the parent node and the child node among all nodes that can be connected to the neighbor node.

Referring to FIG. 5, a flowchart illustrating a method of transmitting a reliability guarantee scheme is shown in the case of transmission from a child terminal to a parent terminal.

More specifically, when a packet arrives (1), it is determined whether the arrived packet is a packet generated by an upper protocol layer of the node or a packet transmitted by another node (parent node, child node) (2). There may be a neighbor node in another node, but since the neighbor node has successfully transmitted to it, it is determined that the neighbor node is registered as its child node through a topology change.

When it arrives from the upper protocol layer (2, Yes), it attempts to transmit a packet to the parent node (5). If the packet is transmitted by another node (2, No), it is determined whether the packet is transmitted by the parent node (3), and when the packet is transmitted by the child node or neighbor node (3, No), an attempt is made to transmit the packet to the parent node (5).

If the transmission is successful (6, Yes), the process ends. If the transmission fails (6, No), it is determined whether the number of retransmissions is exceeded (7). If the number of retransmissions has not exceeded (7, no), the number of transmissions is increased (8), and packet transmission is attempted (5) to the parent node. If the number of retransmissions is exceeded (7, Yes), it is determined whether there is a neighbor node that can be transmitted (9).

If the neighbor node exists (9, Yes), the packet transmission attempt 12 to the neighbor node. If the transmission is successful (13, YES), the neighbor node is changed to the parent node (15) and terminates. If transmission fails (13, no), the neighbor node is removed from the neighbor node list (14), and the neighbor node existence determination (9).

If there is no neighbor node (9, No), it is determined whether the corresponding packet is a packet transmitted from a child node (10). If the node generates a packet (10, Yes), the packet is discarded and network initialization is performed (16) and then terminated. If the node does not generate the packet (10, No), it is a packet transmitted by the child node or the neighbor node. If the child node transmits the packet, the packet is transmitted back to the child node (11) and terminates.

If the packet is received from the parent node (3, Yes), it is determined whether the neighbor node exists (4). If the neighbor node does not exist (4, no), the packet is discarded and network initialization is terminated (17). If there is a neighbor node (4, Yes), it attempts to transmit to the neighbor node (19). If the transfer is successful (19, yes), the topology is changed (21) and the process ends. If the transmission fails (19, no), the neighbor node is deleted from the neighbor node list (20) and it is determined whether another neighbor node exists (4).

In addition, the sequence specified above may be repeatedly performed until the last terminal node. For example, if there is no child node's neighbor (parent and child nodes are not neighbors), it is passed to the child node's child node, and if the child node's child node is the terminal node that originally sent the packet, Can be discarded. In other words, when there is no neighbor node and retransmission to the child node is performed and finally reaches the terminal node, the packet may be discarded.

Referring to FIG. 6, as a path setting table, neighbor node information stored for each node is represented, and a structure is stored in the order of a receiving terminal, a parent terminal, a next hop node, and a neighbor node. For example, in the routing table of SN1, the parent node of SN3 is SN1, and the packet transmitted to GN (generated by SN1, received from SN2 (from neighbor node), or received from SN3 (child node) Since the next hop can be selected and forwarded to GN, if SN1 fails to send to SN3, the neighbor information is seen in the column where the receiver is SN3 and sent to SN2, which is SN3's neighbor. You can try

Referring to (a) of FIG. 6, in order to deliver to GW (Destination) from SN1's point of view, it is sent to GW (Next Hop), and neighboring nodes of GW become Null.

Referring to FIG. 6 (b), when the topology becomes longer, Desination may have a different value from the next hop, where SN1 sends a packet to SN4, the destination is SN4, and the next hop is SN2 (the routing table of SN1). ).

In addition, referring to FIG. 6C, the neighbor node may refer to the remaining nodes except the parent node and the child node among the nodes that can be connected to the corresponding node as the neighbor node. In the problem of retransmission after transmission failure, when SN1 fails to transmit to SN3, the neighbor node of SN3 may be examined, and transmission may be performed to SN2, which is a node connectable to SN1. For example, if the neighboring nodes of SN3 have SN2 and SN4, SN1 may not be able to connect with SN4 and may attempt to transmit through SN2.

Referring to FIG. 7, which illustrates a data transmission procedure for guaranteeing reliability, illustrates a procedure of transmitting a packet to the GN by the SN3. P {end-to-end transmit / receive pair} (single-hop transmit / receive pair), for example, P {SN3-> GN} (SN3-> SN1) is a packet transmitted by SN3 to GN and is transmitted by SN3 to SN1.

Preferably, if the transmission is successful, SN3 transmits a packet to SN1, and when SN1 receives the packet, it forwards to GN. If SN3 fails to transmit to SN1, it attempts to transmit until the number of retransmissions is exceeded. If the transmission fails until the number of retransmissions, SN3 attempts to transmit to its neighboring node SN2, and transfers to GN when SN2 normally receives. If SN1 fails to transmit to GN, it will try to transmit until the number of retransmissions is exceeded, and if it fails to transmit to retransmissions, SN1 will attempt to transmit to its neighboring node, SN2. To pass.

8 to 11 show a transmission procedure.

8 and 9, as an operation scheme when an uplink message transmission fails, it shows a case in which the source terminal fails to transmit.

Referring to FIG. 8, green is a field generated in the MAC layer and yellow is a field generated in the Nwk layer. Beacon is information transmitted for network management in the MAC layer and includes information such as time information about the network synchronizer, parent node information, number of child nodes, battery level, and path cost. In the present embodiments, the Beacon may be interpreted as a message including parent node information and path cost information, but is not necessarily so. Payload depends on the message to be actually delivered and may correspond to information generated by node 1.

In addition, the beacon message is a message that is periodically transmitted, and in FIG. 8, the beacon may mean only that node 1 and node 2 periodically exchange beacons.

Referring to FIG. 9, when there is no neighbor node at node 2, this may mean that there is no connectable node. Therefore, the node 2 may perform the initialization procedure instead of performing the topology change procedure. The initialization procedure may refer to an initial configuration procedure of a node including frequency searching.

Referring to FIG. 10, a method of operating a downlink message transmission failure, which illustrates a case in which a relay terminal fails to transmit.

Referring to FIG. 10, in a method of selecting an A12 neighbor node, whether a neighbor node of a transmitting node is selected or a neighbor node of a receiving node is selected may vary depending on a transmission direction. Referring to FIG. 10, since it is a downlink direction, it is delivered to a neighbor node of a transmitting node (from the gateway to the terminal direction).

Referring to FIG. 11, a topology change procedure is shown.

Referring to the procedure illustrated in FIG. 11 in detail, FIG. 11 illustrates a process of changing a path after being assigned a beacon. First, node 1 receives beacons from nodes neighboring itself (node 2, node 3). The beacon contains MAC layer synchronization information and path cost information. Node 1 receives beacons from Node 2 and Node 3 and then verifies that Node 3's cost is lower than Node 2's cost. Therefore, after registering node 3 as a parent node to register as node 3, broadcast is performed. Then node 2 and node 3 receive it, and node 2 registers node 1 as a neighbor node and node 3 registers node 1 as a child node. We need to tell GW that Node 1 has chosen Node 3 as its parent node (node 4 is considered GW), so we pass the Beacon Req through Node 3. Beacon Req is Nwk layer information, so it forwards to node 3's Nwk layer and node 3 forwards to node 4. Then change the route configuration information (routing table). Other nodes may not notice that Node 1's path has changed, so Topo. Passing State can prevent path information inconsistency.

12 is a flowchart illustrating a procedure of an information transmission method of a network configured in a tree topology according to an embodiment of the present invention. Hereinafter, the present disclosure will be described with reference to FIGS. 2 to 11. A method of transmitting information of a network configured in a tree topology according to an embodiment of the present invention will be described in detail, but the entire contents of the present invention described above with reference to FIGS. 2 to 11 will be described below. It can be applied to the information transmission method of the network configured in the form of a tree topology according to.

Referring to FIG. 12, in the information transmission method of a network configured in a tree topology according to an embodiment of the present invention, in the information transmission method of a network configured in a tree topology including N nodes, i) If the first node that has received the predetermined information fails to transmit the predetermined information to the second node, the first node that fails to transmit searches for a neighbor node of the second node (s1210), ii) When there is a neighbor node of a second node, the first node transmits the predetermined information to the neighbor node of the second node (s1220), and iii) the neighbor node of the second node receives the predetermined information. Transmitting to the second node (s1230). And iv) the second node provides an information transmission method of a network configured in the form of a tree topology including the step of transmitting the predetermined information to a destination (s1240).

In this case, when the first node that has received the predetermined information fails to transmit the predetermined information to the second node, the first node attempts to transmit the predetermined information to the second node more than a predetermined number of times. In some cases, the second node may not receive the predetermined information.

In the present embodiment, the network configured in the tree topology form includes a transmitting node, a receiving node, a parent node of a transmitting node, a neighbor node of a transmitting node, a parent node of a receiving node, and a neighbor node of a receiving node. ii) (s1220), when the first node transmits the predetermined information to a neighbor node of the second node and the transmission is successful, the first node sets the neighbor node of the second node as a parent node. The method may further include setting itself as a child node of the neighbor node of the second node.

In the present embodiment, in step ii) (s1220), when there is no neighbor node of the second node, the first node retransmits the predetermined information to the node that has transmitted the information to itself, and receives the received information. The node may further include the step of transmitting the received information to its neighbor node, but if the transmission is successful, setting the neighbor node as a parent node and setting itself as a child node of the neighbor node.

In this embodiment, the neighboring node transmits the predetermined information to a third node other than the first node and the second node to cause the third node to perform steps i), ii), iii), And iv).

In the present embodiment, step iv) (s1240), wherein the second node becomes another first node and the predetermined information is transferred to another second node according to the steps i), ii) and iii). It may include the step of transmitting the predetermined information to the destination including a plurality of transmission procedures.

In the present embodiment, the predetermined information may be configured in the form of a tree topology, which has a beacon message form.

Meanwhile, the method of improving transmission reliability through transmission of adjacent nodes in a distributed network using a tree topology according to an embodiment of the present invention may also be implemented as computer readable codes on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored.

For example, a computer-readable recording medium may be a ROM, a RAM, a CD-ROM, a magnetic tape, a hard disk, a floppy disk, a removable storage device, a nonvolatile memory (Flash memory). Optical data storage.

The computer readable recording medium can also be distributed over computer systems connected through a computer communication network and stored and executed as readable code in a distributed fashion.

Although a preferred embodiment of the method and apparatus for improving transmission reliability through adjacent node transmission in a distributed network using a tree topology according to the present invention has been described above, the present invention is not limited thereto, and the claims and the details of the invention are described. It is possible to carry out various modifications within the scope of the description and the accompanying drawings, which also belong to the invention.

Claims (7)

A communication device constituting a tree topology network,
The processor included in the communication device,
When a node requesting a beacon allocated from a gateway is set as a child node, a node providing the beacon is set as a parent node, and the remaining nodes are set as neighbor nodes, when receiving beacons from two or more nodes, a path cost Set this one lower node only as the parent node,
When the predetermined information is received, when the predetermined information is a packet generated by an upper protocol layer, a packet transmitted by a child node, or a packet transmitted by a neighbor node, an attempt is made to transmit the received predetermined information to a parent node,
If it fails to transmit the predetermined information to the parent node, the neighbor node is searched; if the neighbor node exists, the predetermined information is transmitted to the neighbor node,
And when the transmission is successful by transmitting the predetermined information to the neighboring node, changing the neighboring node to a parent node and changing itself to a child node of the neighboring node.
The method according to claim 1,
The processor,
And when the predetermined information transmission fails to the neighboring node, removing the corresponding neighboring node from the neighboring node list.
The method according to claim 1,
The processor, if there is no neighbor node,
If the predetermined information is a packet generated in an upper protocol layer, discard the packet and perform network initialization.
And if the predetermined information is a packet transmitted from a child node or a packet transmitted from a neighbor node, the predetermined information is transmitted again.
The method according to claim 1,
The processor,
If the predetermined information is a packet received from a parent node and there is no neighbor node, discard the packet and perform network initialization.
And if the predetermined information is a packet received from a parent node and there is a neighbor node, attempting transmission to the neighbor node.
The method according to claim 4,
The processor,
If the transmission is successful to the neighbor node, change the neighbor node to a parent node,
And when the transmission fails to the neighbor node, delete the neighbor node from the list.
The method according to claim 1,
And wherein the predetermined information has a beacon message form. delete

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