KR20100122792A - Routing method for wireless sensor networks in home automation and communication module of sensor node using it - Google Patents

Abstract

PURPOSE: A routing method for a wireless sensor network in home automation and a communication module of a sensor node using the same is provided to be suitable for small network and reduce the overhead and packet delay. CONSTITUTION: Next hop node among sensor nodes available for communication in a current node is determined(S330). If the next hop node is determines, set the next hop node tot eh current node after resetting the information of current node. Location information of sensor nodes included within a communication radius of current nodes in a current node and shortest distance information with a destination node is received. Next hop node is determined by suing the information received in a current node.

Description

Routing method for wireless sensor networks in home automation and communication module of sensor node using it}

According to the present invention, in a sensor network composed of a plurality of sensor nodes that collect and transmit sensed data of the surroundings, the next hop node is a sensor node that is the shortest distance from the destination node among the sensor nodes that are in communication with the current node. The present invention relates to a routing method for a wireless sensor network and a communication module used in the home automation system. The shortest distance between the sensor node and the destination node relates to a routing method for a wireless sensor network in a reset home automation system using a relationship between a current node and a next hop node when a next hop node is determined, and a communication module used therein. .

Sensor network is a cooperative network by adding objects and physical objects scattered in daily life to communication between human and computer. It is a system that attaches multiple nodes to all necessary places to collect, manage and control information autonomously. to be.

In general, the importance of wireless sensor and sensor network technology is increasing for collecting various information in ubiquitous environment, but due to the limited resources (battery or memory) of the sensor node, it is difficult to manage and thus the efficient use of sensor energy. Increased interest,

The proposed routing protocol in sensor network can be divided into data-centric, hierarchical and location-based routing protocols. In particular, in the location-based routing protocol, not only the sensor collects the information generated in the sensor network but also confirms the location information where the actual data occurred. Therefore, the location-based routing protocol occupies an important position in the routing protocol of the sensor network. On the other hand, as a technique for obtaining position information in a sensor network, a global positioning system (GPS), a received signal strength (RSS), or triangulation is used.

FIG. 1 is a flowchart illustrating a routing method using a greedy algorithm among conventional location-based routing algorithms, and FIG. 2 is a diagram illustrating a routing method using a conventional greedy algorithm.

As shown in FIG. 1, the greedy algorithm is an algorithm developed for location-based routing in an ad-hoc network, and the location information (x _s , y _s ) of the source node S is determined. The location information (x _d , y _d ) of the destination node D is used.

The greedy algorithm refers to a method of transmitting data to the sensor node n ₁ closest to the destination node D among nodes within a communication radius that the source node S can transmit.

Here, x is the current node, n _i is the neighbor node of x, d _{x-> D} is the distance between x and D, the source node (S) senses the surrounding data and the data and other sensor nodes Means a sensor node that can transmit and receive.

The greedy algorithm periodically transmits and receives location information with nodes in the surrounding communication radius, and each node transmits location information of neighbor nodes to a location information storage unit (or hereinafter, 'location table' or 'Ntable' (neighbors'). coordinates of the local node record table) (S110).

Location information storing unit, the current node (x) and the location information of sensor nodes capable of communication is stored, to a destination node (D) of the sensor node distance (d _{x-> D),} the following nearest nodes Set to hop. That is, the initially set d _min and d _ni-> Compare _D d _{ni-> D} <if d _min, d _{ni-> D} By repeating the process of resetting a distance d _min to a destination node (D) (d _{x -> D} ) can determine the nearest node (S120 ~ S150).

In the above method, the location information of the neighboring nodes is transmitted from the storage unit to the nearest node, and routing is repeatedly performed until the data is transmitted to the destination node D (S160).

Therefore, in the routing method using the greedy algorithm, the source node S does not need to know the topology of the entire network, and only uses information of nodes within a communication radius.

However, the routing method using the greedy algorithm has a problem that the number of nodes around the source node S is small so that communication cannot be performed, an optimal path cannot be selected, or an infinite loop falls.

FIG., The data needs to be transmitted to the path d ₁ in the case where the data is sent to the path d ₂ than the power consumption can lead to large packet delay, as illustrated in Fig.

In addition, when data is transmitted along the path d ₃ , after data is transmitted from the source node S to the neighboring node n ₁ , the neighboring node n ₁ is a neighboring node within a radius r of communication, When the n closest n ₂ to the _second destination node (D) of the set to the next hop in the communication radius of the n ₂ is only n _1, so that there n ₂ and n ₁ is repeated is set only the corresponding node to the next hop infinity There is a problem with loops.

Accordingly, the present invention is to solve the problem according to the prior art described above, in calculating the distance between the nodes included in the sensor network and the destination node, the shortest distance between the node of the previous hop and the destination node to which data is transmitted is the previous hop. It is an object of the present invention to provide a routing method for a wireless sensor network and a communication device using the same in a home automation system which is reset to a distance between a node and a current node and a shortest distance between the current node and a destination node.

The present invention also provides a routing method for a wireless sensor network in a home automation system for transmitting data by determining a node having a minimum distance from a destination node among nodes included in a communication radius of a current node as a next hop node and using the same. It is an object to provide a communication device.

A routing method for a wireless sensor network according to an aspect of the present invention is a routing method for a wireless sensor network including sensor nodes in which location information and shortest distance information with a destination node are stored, the shortest with location information and a destination node. A routing method for a wireless sensor network including sensor nodes in which distance information is stored, the method comprising: determining a next hop node among sensor nodes that can communicate in a current node, and resetting information of the current node when the next hop node is determined; And then setting the next hop node as the current node, wherein determining the next hop node and setting the current node are repeated until the next hop node becomes the destination node.

 According to another aspect of the present invention, a communication module of a sensor node used in a wireless sensor network includes location information of a sensor node, shortest distance information with a destination node, and destination nodes received from sensor nodes included in a communication radius of the sensor node. A memory unit for storing the shortest distance information with the memory device, and compares the shortest distance information of the sensor nodes included in the communication radius to determine a next hop node, and determines the shortest distance between the sensor node and the destination node via the next hop node. And a control unit for resetting to the shortest distance and storing the data in the memory unit, and a transceiver for transmitting and receiving data with a sensor node included in the communication radius.

As described above, in the home automation system according to the present invention, a routing method for a wireless sensor network and a communication device using the same are suitable for a small network, reduce overhead and packet delay, and improve adaptability to changes in network topology. There is.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to be limited to the specific embodiment of the present invention, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the second component may be referred to as the first component, and similarly, the first component may also be referred to as the second component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Now, a routing method for a wireless sensor network and a communication module using the same according to an embodiment of the present invention will be described in detail with reference to the drawings, and the same or corresponding components are given the same reference numbers regardless of the reference numerals. Duplicate explanations may be omitted.

3 is a flowchart illustrating a routing method for a wireless sensor network according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating a sensor network for explaining a routing method for a wireless sensor network according to an embodiment of the present invention. to be.

In general, sensor nodes included in the sensor network sense ambient data (temperature, noise, humidity, etc.) and transmit them to the destination node. The sensor network includes a plurality of sensor nodes, and each sensor node may directly transmit and receive data with a destination node or transmit and receive data through another sensor node.

Therefore, sensor nodes that cannot transmit data directly to the destination node can transmit the sensed data to the destination node by forming a routing path.

In the routing method for a wireless sensor network according to an embodiment of the present invention, first, location information of sensor nodes included in a communication radius of a current node and shortest distance information with a destination node are transmitted from a current node (S310 to S320).

Each sensor node is initially set with the location information and the shortest distance information with the destination node (S310), and the current node is connected to the location information and the destination node by a wireless communication method from the sensor node n _i included in the communication radius. The shortest distance information is received (S320).

The current node refers to a sensor node capable of sensing the surrounding data and transmitting the sensed data to the destination node, and may have various names such as a source node and a first sensor node. In addition, the communication radius of the current node means a distance that can transmit and receive data between sensor nodes, and the communication radius may vary according to the performance of the sensor node.

Each sensor node is a location information storage unit (or hereinafter, 'location information') in which location information of other sensor nodes included in a communication radius and shortest distance information (d _{ni-> D} ) between each sensor node and a destination node are recorded. Table 'or' Ntable '(neighbors' coordinates of the local node record table) is implemented.

Therefore, the current node receives and stores the sensor nodes included in the communication radius, the location information and the shortest distance information between each sensor node and the destination node, and recalls the stored information from the location information storage unit (S320). Determine the next hop.

When the shortest distance information between the sensor node and the destination node is stored in the sensor node included in the communication radius, the next hop can be determined using the shortest distance information. If the shortest distance information is not stored, the destination can be determined using the location information of the sensor node. The shortest distance to the node may be calculated and stored in the location information storage unit (S340).

That is, a process of comparing the location information and the shortest distance information of two sensor nodes among the sensor nodes stored in the location information storage of the current node (S350), and setting the sensor node having the relatively shortest distance information as the next hop node. (S360) is repeated to the last sensor node stored in the location information storage unit (S370).

Next, the current node (x) resets the shortest distance between the current node (x) and the destination node (D) to its shortest distance via the next hop node (nexthop) in its location information storage unit (S380). The reset shortest distance information is transmitted to the sensor node included in the communication radius, and the sensor nodes included in the communication radius change the shortest distance information between the current node x and the destination node to the reset value (S390).

Here, the shortest distance between the current node and the destination node (d _{x-> D)} is the shortest distance of the current node and the next hop node (d _{x-> next hop)} and the shortest distance of the next-hop node and the destination node (d _{next hop Is} calculated as the sum of- _{> D} ), which is different from simply calculating the shortest distance between the current node and the destination node.

이며, 이 중 최소는 최단거리가 4인 n₂이므로 다음 홉 노드는 n₂가 된다.As, it is within the sensor network, the sensor nodes if that distribution is the current node (S) communication radius comprising the _{n 1, n 2, n 3} 3 of the sensor node in the (r) of the bar, each sensor shown in Fig. 4 The shortest distance between the node and the destination node

And, of at least n ₂ because it is the shortest distance is four next-hop node is the n _2.

If the next hop node is determined to be n ₂ , the shortest distance between the current node S and the destination node is calculated as 5 as the shortest path via n ₂ . When the next hop n ₂ is located in a straight line connecting the current node and the destination node, the shortest distance and the reset shortest distance between the initially stored current node and the destination node may be set to be equal.

After the shortest distance with the destination node of the current node is reset, the next hop node is set as the current node and the next hop node is determined by using the shortest distance information with the destination node of the sensor node included in the communication radius of the current node. .

That is, as shown in FIG. 4, n ₂ is set as the current node in the sensor node included in the communication radius of the n ₂ (S, n ₃₎ from among at least the shortest distance to the destination node, the sensor node, the next-hop Is determined.

이므로 다음 홉은 n₃가 된다. The shortest distance between sensor node S and the destination node has been reset to 5, and the shortest distance between sensor node n ₃ and the destination node is

So the next hop is n ₃ .

로 재설정된다. 또한, n₂노드는 통신반경 내에 포함되는 센서 노드들에게 재설정된 최단거리 정보를 전송한다. Similarly, the shortest distance between the current node n ₂ and the destination node is calculated as the shortest distance through the next hop node n ₃ , so the shortest distance between the current node n ₂ and the destination node

Is reset to. In addition, the n ₂ node transmits the reset shortest distance information to the sensor nodes included in the communication radius.

로 변경되고, n₃노드가 다음 홉 노드를 결정할 때 상기 변경된 n₂노드와 목적지 노드의 최단거리 정보가 사용되므로 상기의 문제점을 해결할 수 있다.The routing method using the general greedy algorithm is a routing method in which the shortest distance between the sensor node and the destination node does not change. When applied to FIG. 4, the next hop node from the source node S is set to n ₂ nodes. set to the next-hop node of a node n ₂ n ₃ is a node, the next hop node of the node n ₃ is set to n ₂ nodes again there is a problem that an infinite loop. However, the routing method of the present invention then when hop node is set if the current since the shortest distance between the node and the destination node reset, the next-hop node of the n _second node is set to n ₃ nodes, n of the _second node and a destination node, Shortest distance from 4 to 1+

When the n ₃ node determines the next hop node, the shortest distance information of the changed n ₂ node and the destination node is used, thereby solving the above problem.

In this manner, the routing path is repeatedly determined until the next hop node becomes the destination node, and data sensed at the current node may be transmitted from the current node to the destination node through the routing path.

That is, as shown in Figure 4, the transmission path of the first sensing data is the source node (S)-> n ₂ node-> n ₃ node-> n ₄ node-> n ₅ node-> n ₆ node-> n _It becomes ₇ node-> destination node (D).

Also, the second and subsequent sensing data is determined by the shortest distance between the reset sensor node and the destination node. Therefore, the second and subsequent data transmission paths become the source node (S)-> n ₃ node-> n ₄ node-> n ₅ node-> n ₆ node-> n ₇ node-> destination node (D). Data transfer is possible.

FIG. 5 is a graph comparing a received packet rate of a routing method for an AODV and an ad-hoc on-demand distance-vector (AODV) routing method according to an embodiment of the present invention, and FIG. 6 is an embodiment of the present invention. Is a graph comparing the packet average delay time between the routing method for the wireless sensor network and the ad-hoc on-demand distance-vector (AODV) routing method.

Scenario 1 is a case where 560 packets are transmitted from three source nodes, and each routing method is used to compare the number of packets sent to the destination node. The packet transmission rate is initially determined by the number of data packets transmitted and received by the source node. The ratio of the number of packets received. In the case of using the AODV routing method, 384 packets of the 560 transmission packets are transmitted to the destination node, which shows a packet transmission rate of 68.57%, whereas when using the routing method for the wireless sensor network according to the present invention, 518 packets are sent to the destination node. The packet transmission rate was 92.5%.

In the case of Sinao 2, 1718 packets are transmitted from 9 source nodes. In case of using the AODV routing method, 860 packets are received. In the case of using the routing method of the present invention, 1585 packets are received to obtain a packet transmission rate of 50.06% and 92.26%. Seemed.

In scenario 3, 2097 packets are transmitted from 11 source nodes, and the packet transmission rate is 43.16% and 82.98% by receiving 905 packets using the AODV routing method and 2097 packets using the routing method of the present invention. .

Scenarios 1 to 3 compare several embodiments and it can be seen that the routing method of the present invention has superior packet transmission rate compared to the AODV routing method.

The packet average delay time is a one-way latency for transmitting a packet from a source node to a destination node, and represents a response time of the routing method.

As shown in Figure 6, it can be seen that the packet average delay time during packet transmission by the routing method of the present invention is reduced. That is, the routing method according to the present invention was able to reduce the delay of 70.43% in scenario 1, 53.79% in scenario 2, and 10.11% in scenario 3 than in the AODV routing method.

7 is a graph comparing routing overhead of a routing method for an AODV (ad-hoc on-demand distance-vector) routing method for a wireless sensor network according to an embodiment of the present invention.

Routing overhead represents the load due to routing packets, and as the number of routing packets increases, the network load increases.

In scenario 2, the number of command packets is 5500 when the routing method of the present invention is used, and the number of command packets is 13500 when the AODV routing method is used, which is higher than the number of command packets when the AODV routing method is used when the routing method of the present invention is used. It can be seen that 59.69% decrease.

In scenario 1, the routing method of the present invention is 15.78% higher than the number of command packets when the AODV routing method is used, but in scenarios 2 and 3, it is 59.69% and 64.14%, respectively.

That is, as the number of sensor nodes increases, using the routing method of the present invention can reduce the routing overhead.

8 is a block diagram illustrating a configuration of a communication module of a sensor node included in a wireless sensor network according to an embodiment of the present invention.

As shown in FIG. 8, the communication module 800 of the sensor node includes a memory unit 810, a controller 820, and a transceiver 830.

 The memory unit 810 stores the position information of the sensor node, the shortest distance information with the destination node, and the shortest distance information with the destination node received from the sensor nodes included in the communication radius of the sensor node. The memory unit 810 may store location information of sensor nodes included in a communication radius and shortest distance information with a destination node in a location information storage unit.

The controller 820 determines the next hop node by comparing the shortest distance information of the sensor nodes included in the communication radius, and resets the shortest distance between the sensor node and the destination node to the shortest distance via the next hop node. Control to be stored in

The transceiver 830 transmits and receives a sensor node and sensing data included in a communication radius, location information of the sensor node, shortest distance information, and the like.

Each of the sensor nodes included in the wireless sensor network is provided with a communication module 800, and may sense location information of sensor nodes included in a communication radius while the sensed data is transmitted.

The shortest distance to the destination node stored in the memory 810 of the communication module may be initially set to a distance when data is directly transmitted between each sensor node and the destination node, and the next hop node to which the data is transmitted is determined. The shortest distance between the current node and the destination node is reset.

The reset shortest distance may be calculated as the sum of the distance of direct data transmission between the sensor node and the next hop node and the distance of direct data transmission between the next hop node and the destination node.

The routing method in the wireless sensor network can be written as a computer program, and codes and code segments constituting the program can be easily inferred by a computer programmer in the art.

In addition, the program is stored in a computer readable medium (computer reader meadia), can be read and executed by the computer to implement the sensing data routing method of the wireless sensor network.

The information storage medium includes a magnetic recording medium, an optical recording medium and a carrier wave medium.

The above embodiments of the present invention are disclosed for the purpose of illustration, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit and scope of the present invention. Should be considered to be within the scope of the following claims.

1 is a flowchart illustrating a routing method using a greedy algorithm of a conventional location-based routing algorithm.

2 is a diagram illustrating a sensor network for explaining a routing method using a conventional greedy algorithm.

3 is a flowchart illustrating a routing method for a wireless sensor network according to an embodiment of the present invention.

4 is a diagram illustrating a sensor network for explaining a routing method for a wireless sensor network according to an exemplary embodiment of the present invention.

FIG. 5 is a graph comparing received packet ratios between a routing method for a wireless sensor network and an ad-hoc on-demand distance-vector (AODV) routing method according to an embodiment of the present invention.

FIG. 6 is a graph comparing packet average delay times between a routing method and an AODV (ad-hoc on-demand distance-vector) routing method for a wireless sensor network according to an exemplary embodiment of the present invention.

7 is a graph comparing routing overhead of a routing method for an AODV (ad-hoc on-demand distance-vector) routing method for a wireless sensor network according to an embodiment of the present invention.

8 is a block diagram illustrating a configuration of a communication module of a sensor node included in a wireless sensor network according to an embodiment of the present invention.

Claims (8)

A routing method for a wireless sensor network comprising sensor nodes storing location information and shortest distance information with a destination node, the method comprising: Determining a next hop node of the sensor nodes that can communicate at the current node; And And if the next hop node is determined, resetting information of the current node and setting the next hop node as the current node. The determining of the next hop node and setting the current hop node may include: Routing method for a wireless sensor network that repeats until the hop node becomes the destination node. The method of claim 1, Determining the next hop node among the sensor nodes that can communicate in the current node, (a) receiving the location information of the sensor nodes included in the communication radius of the current node from the current node and the shortest distance from the destination node; And (b) determining a next hop node using the information received from the current node; When the next hop node is determined, resetting information of the current node and setting the next hop node as the current node, (c) resetting and storing the shortest distance between the current node and the destination node to the shortest distance via the next hop node in the current node; And (d) configuring the next hop node as a current node. The method of claim 2, In the determining of the next hop node using the received information, the sensor node having the shortest distance to the destination node among the sensor nodes included in the communication radius is determined as the next hop node. Routing method for The method of claim 2, Resetting the shortest distance of the current node and the destination node to the shortest distance via the next hop node in the current node, wherein the shortest distance is the shortest distance of the current node and the next hop node and the next hop node and the destination node. Routing method for a wireless sensor network, characterized in that calculated as the sum of the shortest distance. The method of claim 2, Routing method for a wireless sensor network, characterized in that the data collected at the current node is transmitted to the destination node through the routing path determined from the current node to the destination node. A memory unit for storing location information of a sensor node, shortest distance information with a destination node, and shortest distance information with a destination node received from sensor nodes included in a communication radius of the sensor node; The next hop node is determined by comparing the shortest distance information of the sensor nodes included in the communication radius, and the shortest distance between the sensor node and the destination node is reset to the shortest distance via the next hop node and stored in the memory unit. A control unit; And And a transceiver for transmitting and receiving data with a sensor node included in the communication radius. The method of claim 6, And the shortest distance to the destination node stored in the memory unit is initially set to a distance when data is directly transmitted between each sensor node and the destination node. The method of claim 6, The reset shortest distance is calculated as the sum of the distance of direct data transmission between the sensor node and the next hop node and the distance of direct data transmission between the next hop node and the destination node.

Images