KR20200028645A - A Mobile-Sink Based Energy-efficient Clustering Scheme in Mobile Wirless Sensor Networks - Google Patents

Abstract

The present invention relates to a mobile sink-based energy efficient clustering technique in a mobile sensor network. More particularly, the present invention relates to a mobile sink-based energy efficient clustering technique in a mobile sensor network which increases energy when selecting a new cluster head according to the mobility of mobile sensor nodes, and divides the entire network into multiple cluster groups based on mobile sinks, taking mobility issues into account, thereby reducing overall energy consumption.

Description

{A Mobile-Sink Based Energy-efficient Clustering Scheme in Mobile Wirless Sensor Networks}

The present invention relates to a mobile sink-based energy-efficient clustering technique in a mobile sensor network, more specifically, to increase energy when selecting a new cluster head according to the mobility of mobile sensor nodes, and multiple clusters based on a mobile sink based on the entire network. Divided into groups, it relates to a mobile sink-based energy efficient clustering technique in a mobile sensor network that considers mobility problems and reduces overall energy consumption.

The present invention relates to a mobile sink-based clustering technique.

Recently, with the active research of wireless sensor networks, the performance of sensor nodes, such as having mobility and location recognition functions, is gradually improving. One of the most important goals of such a sensor network is to transmit data generated from a large number of mobile sensor nodes to a sink node in consideration of energy efficiency.

Mobile Wireless Sensor Networks (MWSNs) consume a lot of energy to transmit sensed data to a fixed sink because sensor nodes move. In order to solve this problem, the use of Mobile Sink, which collects data while the sink moves inside the network, is being studied.

Among the studies related to mobile sinks, in Non-Patent Document 1, a new method of improving Non-Patent Document 2 using a mobile sink and a Rendezvous Point (RP) was introduced. In addition, a method of temporarily storing data of several sensor nodes and transmitting them to a PR has been studied. Typically, in the non-patent document 3 method, a sensor having an advantageous energy consumption is selected as an RP node by calculating a weight of the sensor node. In Non-Patent Document 4, an energy efficient cluster method using a mobile node and an immune algorithm was introduced.

In Non-Patent Document 5, Wireless Sensor Networks (WSNs) with fixed sinks are often energy hole problems, i.e., the energy consumption of sensors in the vicinity of the sink or on a specific path is much faster than other nodes, resulting in network fragmentation. Since an isolated node is created, MECA (Mobile-sink based Energy-efficient Clustering Algorithm) was proposed to solve this problem. Sink mobility is divided into three categories: random mobility, predictable mobility, and adjustable mobility. Arbitrary mobility is relatively easy to operate because it does not have real-time information, but the sink may move back to an area with less energy. Predictable mobility knows the sink's tracking information well and waits for the sink to come, which can lead to data transmission delays. Adjustable mobility has the function of adjusting the movement of the sink according to the situation of the sensors, but the structure is too complicated and overload occurs.

In the research related to MWSNs, LEACH-Mobile (non-patent document 6), M-LEACH (non-patent document 7) with improved non-patent document 2, and MBC: Mobility-based Clustering Protocol (non-patent document 8) with improved M-LEACH Clustering techniques have been proposed in consideration of mobility of sensor nodes.

In LEACH-Mobile of Non-Patent Document 6, when the topology changes according to the movement of the node, the moving node communicates with a specific cluster head (CH) in a time slot according to the TDMA (Tine Division Multiple Access) schedule. Whether it is possible or not, the node to be a cluster member (CM) is determined and the cluster is reconfigured.

Non-Patent Document 7 is a method of selecting a new CH using information sent by each CH by placing an invitation phase in the middle of the round in consideration of the mobility of the sensor node. Non-patent document 7 adopts single-hop communication for data transmission from CH to BS, so energy consumption increases as the network size increases and mobility of the mobile sensor node is severe. It is impossible to prepare.

Non-Patent Document 8 improves the problem of Non-Patent Document 7 to reduce energy consumption by adopting multi-hop communication for data transmission from CH to BS, and for each frame in case the mobility of the mobile sensor node is severe. We proposed a method for re-selecting the least expensive CH using various information of CH. However, there is a disadvantage of consuming too much energy to select CH.

(Non-Patent Document 1) S. Mottaghi and M. R. Zahabi, "Optimizing LEACH clustering algorithm with mobile sink and rendezvous nodes," AEU-Int. Electron. Commun., Vol. 69, no. 2, pp. 507-514, Feb. 2014. (Non-Patent Document 2) W. B. Heinzelman, A. P. Chandrakasan, and H. Balakrishnan, "An application-specific protocol architecture for wireless microsensor networks", IEEE Transactions on Wireless Communications, Vol. 1, No. 4, pp. 660-670, Oct. 2002. (Non-Patent Document 3) H. Salarian, K. W. Chin, and F. Naghdy, "An energy-efficient mobilesink path selection strategy for wireless sensor networks", IEEE Trans. Veh. Technol., Vol. 63, No. 5, pp. 2407-2419, June 2014. (Non-Patent Document 4) Mohammed AZ, Sabah MA, Nabil S., Shigenobu S., "Mobile Sink-Based Adaptive Immune Energy-Efficient Clustering Protocol for Improving the Lifetime and Stability Period of Wireless Sensor Networks," IEEE Sensors Journal, Vol . 15, No. 8, 2015. (Non-Patent Document 5) Jin Wang, Yue Yin, Jeong-Uk Kim, Sungyoung Lee, Chin-feng Lai, "A Mobile-Sink Based Energy-Efficient Clustering Algorithm for Wireless Sensor Networks", Computer and Information Technology (CIT), 2012 IEEE 12th International Cnference on 2012 Oct, pp. 678-683, 2012. (Non-Patent Document 6) D. S. Kim and Y. J. Chung, Self-organization routing protocol supporting mobile nodes for wireless sensor networks ", Proceedings on the 1st International Multi Symposium on Computer and Coputational Sciences, pp. 622-626, June 2006. (Non-Patent Document 7) Lan Tien Nguyen, Xavier Defago, Razvan Beuran, and Yoichi Sinoda, "An Energy Efficient Routing Scheme for Mobile Wireless Sensor Networks", Wireless Communication Systems. 2008. ISWCS '08 IEEE International Symposium on Reykjavik, pp. 568-572, Oct. 2008. (Non-Patent Document 8) S. Deng, J. Li, and L. Shen, "Mobility-based clustering protocol for wireless sensor networks with mobile nodes", IET Wireless Sensor Systems, Vol. 1, No. 1, pp. 39-47, Mar. 2011. (Non-Patent Document 9) T. Taleb, E. Sakhaee, A. Jamalipour, K. Hashimoto, Nei Kato and Yoshiaki Nemoto, "A Stable Routing Protocol to Support ITS Services in VANET Networks", IEEE Transactions on Vehicular Technology, (2007 ), pp.3337-3347. (Non-Patent Document 10) Hyunsook Kim, "An Efficient Clustering Scheme for Data Aggregation Considering Mobility in Mobile Wireless Sensor Networks", International Journal of Control and Automation, vol. 6, no. 1, Feb. 2013, pp. 221-234

The present invention aims to solve the problems of the prior art as described above.

Specifically, the object of the present invention is to increase energy efficiency when selecting a new CH according to the mobility of mobile sensor nodes based on M-LEACH and MBC protocols, and to make the network structure a mobile sink based on mobility and energy consumption. It is to provide an energy-efficient clustering technique based on a mobile sink in a mobile sensor network that reduces energy consumption when configuring and transmitting data from a CH to a sync.

The technical problems to be achieved by the present invention are not limited to the above-mentioned problems, and other technical problems not mentioned can be clearly understood by those skilled in the art from the following description. There will be.

In the mobile sensor network according to the present invention for achieving this purpose, the mobile sink-based energy-efficient clustering technique allows the sensor node to send information including one or more of its ID, location, and residual energy to the base station (BS) through the sink. The first step of sending; A second step of designating a virtual cluster group and cluster by using information received from each sensor node at the base station, and designating a cluster head (CH) and a Rendezvous Point (RP) of each cluster; A third step in which the sensor nodes select CH and CH candidates; A fourth step of configuring a node transmission time by broadcasting a time division multiple access (TDMA) schedule to each cluster member (CM) by the CH; A fifth step of transmitting the sensed data from the sensor node to the sink through CH; It characterized in that it comprises a.

In the frame that becomes the CH replacement cycle, each sensor node further comprises selecting a new CH as the closest position among the CH and CH candidates it stores.

In the second step, the base station uses the information received from each sensor node at the base station to fly the entire network into several groups; Dividing each group into a plurality of virtual clusters; Setting the center of each virtual cluster as the RP of the sink; Selecting a CH using any one or more of mobility and energy remaining among nodes among nodes in the center of the cluster; It characterized in that it comprises a.

)가 제일 좋은 센서 노드를 CH로 선택하며, 다음의 수학식에 의해 CH 적합도가 산출되는 것을 특징으로 한다.The step of selecting the CH is CH fitness (

) Is selected as the best sensor node as CH, and the CH fitness is calculated by the following equation.

는 각 센서 노드의 에너지 잔량,

은 각 센서 노드의 초기 에너지 잔량이고,

는 가중치로서 시스템 및 환경에 따라 조정된다.)(Here, Central-step is close to the center of the virtual cluster area, LCT-step is the degree of node mobility,

Is the energy level of each sensor node,

Is the initial energy level of each sensor node,

Is a weight and is adjusted according to the system and environment.)

As described above, the present invention increases energy efficiency when selecting a new CH according to the mobility of mobile sensor nodes based on M-LEACH and MBC protocols, and configures the network structure based on mobility and energy consumption based on mobile sinks. Accordingly, there is an effect of providing a mobile sink-based energy efficient clustering technique in a mobile sensor network that reduces energy consumption when transmitting data from a CH to a sync.

The technical effects of the present invention are not limited to the technical effects mentioned above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the description of the claims. There will be.

1 is a diagram showing a network structure according to an embodiment of the present invention.
2 is a flowchart of a MECM technique according to an embodiment of the present invention.
3 is a diagram illustrating selection of CH and CH candidates according to an embodiment of the present invention.
4 is a diagram illustrating a step of selecting a new CH during a steady state according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For reference, the size of a component, the thickness of a line, and the like shown in the drawings referred to for explaining the present invention may be somewhat exaggerated for convenience of understanding. In addition, the terms used in the description of the present invention are defined in consideration of functions in the present invention, and thus may vary according to a user, an operator's intention, and customs. Therefore, the definition of this term should be based on the contents of the present specification.

In addition, although a preferred embodiment of the present invention will be described with reference to the accompanying drawings in which the object of the present invention can be specifically realized, this is for easier understanding of the present invention, and the scope of the present invention is limited by it. It is not. In addition, in describing an embodiment of the present invention, the same name and the same code are used for the same configuration, and additional description will be omitted.

Prior to the detailed description of each constituent step of the present invention, terms or words used in the specification and claims should not be interpreted as being limited to a conventional or lexical meaning, and the inventor is the best way to explain his or her invention. Based on the principle that the concept of terms can be properly defined in order to be described as, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention. Therefore, the configuration shown in the embodiments and drawings described in this specification is only one of the most preferred embodiments of the present invention and does not represent all of the technical spirit of the present invention, and thus can replace them at the time of application. It should be understood that there may be equivalents and variations.

1 is a diagram showing a network structure according to an embodiment of the present invention.

Referring to Figure 1, the network structure of the model according to an embodiment of the present invention is divided into several cluster groups, and is divided into several clusters for each group. The radius of one group is R.

-You can operate one sink per cluster group and increase the number of cluster groups if the overall network size increases.

-All sensor nodes have the same initial energy value. In addition, the sink has sufficient battery resources and has excellent computing power.

-All nodes can know their location with technology such as Global Position System (GPS). In addition, the base station (BS) can know the location of each sensor node and sink, and can be determined for each round.

2 is a flowchart of a MECM technique according to an embodiment of the present invention.

In the MECM technique, one round is divided into an initial set-up phase, a steady-state phase, and an invitation phase, similar to the M-LEACH protocol. The setup phase is further divided into detailed steps. The first step of the sensor node sending information including one or more of its ID, location, and residual energy to the base station (BS) through the sink, each sensor node in the base station The second step of designating the virtual cluster group and cluster using the information received from the cluster, and specifying the cluster head (CH) and rendezvous point (RP) of each cluster, each sensor node uses its message A third step of selecting a desired CH and a CH candidate includes a fourth step of configuring a node transmission time by broadcasting a time division multiple access (TDMA) schedule to each cluster member (CM). In this way, an actual cluster is formed.

In the steady state stage, the sensor nodes transmit the sensed data to the sink through the CH (step 5).

In the frame that becomes the CH replacement cycle, each sensor node selects the new CH that has the closest position among its own CH and CH candidates.

In addition, the overall CH is rebalanced by placing an invitation in the middle of the round.

The flow chart of the MECM technique according to an embodiment of the present invention is as shown in FIG. 2, and the detailed description will be further described.

Each sensor node sends information such as its ID, location, and residual energy to the base station through a sink. The base station divides the entire network into several groups as shown in FIG. 1 by using the information sent by the sensor nodes, and divides the group into several virtual clusters to select the center as the RP of the sink.

In addition, among the nodes in the center of the cluster, CH is selected using one or more of mobility and remaining energy of the node. At this time, the base station specifies the cluster size and number by appropriately combining the size, density, and number of sensor nodes of the network. However, the number of nodes in the cluster is adjusted similarly. The actual cluster is formed by using the strength of the advertisement message sent by the CH specified by the base stations of each sensor node. At this time, the CH with a little lower intensity is stored as a CH candidate for future use. A detailed description of this will be given later in '(1) Cluster Formation and Cluster Head Selection'.

When each CM transmits the sensed information to the CH according to the TDMA schedule sent by the CH, the CH merges the information and transmits the information to the sink at the RP point, and the sinks transmit the received information to the base station. At this time, the sink continuously rotates clockwise (or counterclockwise) as shown in FIG. 1 to receive data from CH in the RP.

In the middle of each round, there is an invitation phase, where the CHs broadcast their information to surrounding sensor nodes. Each node uses the information sent by the CH to select a new CH that is best for them, and sends a join signal to the corresponding CH. The CH creates a new TDMA schedule using the information and broadcasts it to the nodes of the cluster. For details, continue in '(2) Cluster head replacement and slot use'.

The advantage of the MECM technique is that the entire network can be divided into several cluster groups to maintain performance even on large networks. In addition, since the RP of the sink is located in the center similar to the CH, it is easy to operate the system and reduces the energy consumption to transmit from the CH to the sink. In terms of the mobility of the sensor node and the CH selection, a new CH is selected through the invitation stage to cope with the mobility of the node, and furthermore, in the middle of each frame, there is a CH replacement cycle according to the degree of mobility of the node. At this time, by selecting a new CH among the CH candidates stored by the sensor node, energy consumption accompanying it can be reduced.

(1) Cluster formation and cluster head selection

)가 제일 좋은 센서 노드를 CH로 선택한다.Each sensor node sends information for forming a cluster to a base station through a sink node. The base station is divided into several virtual clusters as shown in FIG. 1 by using the information sent by the sensor nodes. And, among the nodes in the center of the cluster, the CH fit is calculated using the mobility of the node and the remaining energy (

Select the best sensor node as CH.

The CH goodness of fit is calculated by the following formula.

는 각 센서 노드의 에너지 잔량,

은 각 센서 노드의 초기 에너지 잔량이고,

는 가중치로서 시스템 및 환경에 따라 조정된다.Here, the central-step represents the degree of closeness to the center of the virtual cluster area, and becomes one of steps 1 to 9, and the first step is the closest to the center. The LCT-step uses the Link Connection Time (LCT) to determine the level of node mobility in the previous round from 1 to 9 levels, with the first level being the least mobile and the ninth level being the highest. LCT is used to measure the mobility of nodes, such as node speed and direction of movement.

Is the energy level of each sensor node,

Is the initial energy level of each sensor node,

Is a weight and is adjusted according to the system and environment.

The base station divides the cluster group into several virtual clusters, and the consideration is the density of sensor nodes in the cluster group. If the density is uniform, it can be divided into clusters of the same size, but if the density is not uniform, the number of sensor nodes that can belong to each cluster must be considered. If the density is high and the number of nodes in the cluster is large, an overload of CH may occur, thereby affecting network life. Therefore, in one embodiment of the present invention, the partition of the virtual cluster is considered in consideration of the size and density of the cluster.

Assigning CH to the center of the cluster as much as possible is to make the energy consumption when transmitting data by making the distance between CM and CH similar. This approach helps the life of the entire network.

When the sensor node is fixed, this method may cause an energy hole problem in which energy use is concentrated in a specific area, but does not occur when the nodes are mobile. In addition, by designating the RP in the center of the cluster and placing the CH in the center of the cluster, energy consumption can be reduced when transmitting data of the CH to the sink.

The base station sends a message to the designated CH, and each CH informs surrounding sensor nodes that it is selected as the CH. The sensor nodes use the strength of the message to send a JOIN message to the strongest CH. Also, as shown in FIG. 3, CHs with slightly weaker strength are stored as CH candidates and used when designating new CHs later.

(2) Cluster head replacement and slot use

4 is a view showing a step of selecting a new CH during a normal state according to an embodiment of the present invention, the slot structure of the MECM is shown in FIG. 4.

In preparation for the mobility of the sensor node that may occur during the steady-state phase, the CM selects the CH that is suitable for it. At this time, it is not executed every frame like MBC (Mobility-based Clustering), but is performed during the CH replacement cycle using the following equation. This is because the energy consumption is too large if CH is replaced too frequently.

는 한 라운드의 프레임 중에서 현재 프레임이 CH 교체 주기일 확률이다.

Is the probability that the current frame is a CH replacement cycle among the frames of a round.

The method of selecting a new CH during the steady state consists of three detailed steps as shown in FIG. 4. First, each CH broadcasts information such as its location and the remaining energy. Each CM then selects a new CH using the information sent by the CH and sends JOIN and DIS-JOIN messages. Finally, CH broadcasts the TDMA schedule to the CM.

In a mobile sensor network according to an embodiment of the present invention, a mobile sink-based energy efficient clustering technique (MECM) increases energy efficiency when selecting a new CH according to mobility of mobile sensor nodes. In addition, the network structure is configured based on the mobile sink in consideration of mobility and energy consumption, thereby reducing the energy consumption when transmitting data from the CH to the sink.

In an embodiment of the present invention, the initial Ch selection is determined as the sensor node having the best CH suitability. Also, considering mobility, when switching to a new CH during a round, it is decided to be the closest among the current CH and the stored CH candidate. The network is divided into several groups, and mobile sinks are arranged for each group to send data from the CH to the sink, reducing energy consumption and maintaining performance even on large networks.

Although described above with reference to the drawings according to an embodiment of the present invention, those of ordinary skill in the art to which the present invention belongs may be able to perform various applications, modifications, and adaptations within the scope of the present invention based on the above contents will be. Accordingly, the true protection scope of the present invention should be defined only by the appended claims.

Claims (4)

A first step in which the sensor node sends information including one or more of its ID, location, and residual energy to the base station (BS) through the sink;
A second step of designating a virtual cluster group and cluster by using information received from each sensor node at the base station, and designating a cluster head (CH) and a Rendezvous Point (RP) of each cluster;
A third step in which the sensor nodes select CH and CH candidates;
A fourth step of configuring a node transmission time by the CH broadcasting a Time Division Multiple Access (TDMA) schedule to each CM (Cluster Member);
A fifth step of transmitting the sensed data from the sensor node to the sink through CH; Energy efficient clustering method based on a mobile sink in a mobile sensor network, comprising: According to claim 1,
In the frame that becomes the CH replacement cycle, each sensor node further comprises the step of selecting a new CH as the one with the closest position among the CH and CH candidates that it stores, and mobile sink-based energy efficient clustering in the mobile sensor network. technique
According to claim 1,
The second step is
Step of dividing the entire network into a plurality of groups using information received from each sensor node at the base station;
Dividing each group into a plurality of virtual clusters;
Setting the center of each virtual cluster as the RP of the sink;
Selecting a CH using any one or more of mobility and energy remaining among the nodes in the center of the cluster; An energy efficient clustering technique based on a mobile sink in a mobile sensor network, comprising:
According to claim 3,
The step of selecting the CH
CH goodness of fit (

) Selects the best sensor node as CH,
A mobile sink-based energy efficient clustering technique in a mobile sensor network characterized in that the CH fitness is calculated by the following equation.

(Here, Central-step is close to the center of the virtual cluster area, LCT-step is the degree of node mobility,

Is the energy level of each sensor node,

Is the initial energy level of each sensor node,

Is a weight and is adjusted according to the system and environment.)

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