Performance modeling of the LEACH protocol for mobile wireless sensor networks

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Abstract

In many wireless sensor network applications, nodes are mobile, while many protocols proposed for these networks assume a static network. Thus, it is important to evaluate if a traditional protocol designed for a static network can tolerate different levels of mobility. This paper provides an analytic model to investigate the effect of mobility on a well-known cluster-based protocol, LEACH. The model evaluates data loss after construction of the clusters due to node mobility, which can be used to estimate a proper update interval to balance the energy and data loss ratio. Thus, the results can help the network designer to adjust the topology update interval given a value of acceptable data loss threshold. A practical approach to increase the mobility tolerance of the protocol is applying a buffer zone to the transmission ranges of the nodes. The model is extended in order to consider the effect of buffer zone. To validate the analytic evaluations, extensive simulations are conducted and correctness of the evaluations is tightly verified.

Research highlights

► A well-known protocol for wireless sensor networks, LEACH is analyzed against mobility. ► The model evaluates data loss after construction of the clusters due to node mobility. ► The model sets a topology update interval to balance the energy and data loss ratio. ► Mobility tolerance is increased by the buffer zone method before results are analyzed. ► The optimum value of buffer zone is obtained through the model.

Introduction

Wireless sensor networks drew attention of researchers in different fields in the last decade. These networks are used for several applications such as surveillance, habitant observation, and health monitoring. Authors in [20] investigate the design space of these networks and provide several example applications; from 15 different applications, 10 applications are completely mobile and one of them is partially mobile. Thus, several applications of wireless sensor networks are inherently mobile. For example, ZebraNet [9] is a mobile Wireless Sensor Network (WSN) being used to observe the behavior of wild animals within a spacious habitat (e.g., wild horses, zebras, and lions) at the Mpala Research Center in Kenya. Another example is a sensor network used to monitor sub-glacier environments at Briksdalsbreen, Norway, with the overall goal of better understanding the Earth’s climate [13]. Of particular interest are displacements and the dynamics inside the glacier. A lengthy observation period of months to years is required.

In spite of the fact that several applications of WSNs are mobile, many protocols for wireless sensor networks are provided in the literature based on the assumption that nodes are static. Even in several static scenarios, e.g. wireless sensor networks deployed in a forest, it is worthwhile to foresee some small levels of mobility caused by, say wind or water flows. Thus, analysis of the effect of mobility on the performance of these protocols and evaluation of the level of mobility each of these protocols can tolerate as well as analysis of the efficiency of some proposed methods to increase the mobility tolerance of these protocols are of prime importance in designing of mobile wireless sensor networks.

In this paper, an analytic performance model is provided to evaluate the performance of one of the well-known and classic protocols proposed for wireless sensor networks, i.e. Low-Energy Adaptive Clustering Hierarchy (LEACH) [7], [8], which introduces a random clustering scheme for wireless sensor networks. In this protocol, data aggregation is made possible using the clustering scheme, while dynamic re-establishment of the clusters balances the energy consumption over the nodes. The idea behind the LEACH protocol has led to different research studies [6], [22], [10]. The model provided here accurately evaluates the increase in data loss ratio after construction of the clusters due to node mobility. The results can be used by network designers to determine a proper interval for reconstruction of the clusters given a threshold on acceptable data loss ratio.

A general, simple, and widely used approach to increase the mobility tolerance of wireless network protocols is extending the transmission area of the nodes by a buffer zone [23], [24]. The analytic model is extended to consider different values of buffer zone. A large value of buffer zone increases the transmission energy on the one hand and decreases the data loss ratio on the other hand. Thus, the model provided in this paper can help the network designers to balance between the energy for transmission, the energy for topology update, and the minimum acceptable data loss ratio. In order to validate the analytic model an extensive simulation is conducted and the analytic results are tightly validated by the simulation results.

The rest of the paper is organized as follows. The next section provides some related work. Section 3 gives an introduction to the LEACH protocol. Section 4 evaluates the effect of mobility on the protocol. Section 5 suggests applying a value of buffer zone to increase the mobility tolerance and evaluates the results. Section 6 evaluates the energy consumption of the protocol and provides an approach to optimize the energy consumption. Section 6 provides simulation results and the final section concludes the paper.

Section snippets

Related work

In fact, cluster-based approaches for routing in wireless sensor networks are suitable for habitat and environment monitoring, which requires a continuous stream of sensor data. The cluster-based routing protocols are investigated in several research studies. For example, the work in [18] shows that a 2-tier architecture is more energy efficient when hierarchical clusters are deployed at specific locations. Bandyopadhyay and Coyle [2] describe a multi-level hierarchical clustering algorithm,

The LEACH protocol

The LEACH protocol is one of the most popular hierarchical routing algorithms for sensor networks [1]. Basically, LEACH is a dynamic clustering method. In this method, time is partitioned into fixed intervals with equal length, which is called topology update interval or round here. At the beginning of each interval, each sensor becomes a cluster head (CH) with some predefined probability. The cluster heads then broadcast messages to their neighbors. Other sensors receive messages and join a

The effect of mobility

Mobility of nodes can lead to disconnection of cluster members from their cluster heads that causes data loss. Thus, as the velocity of nodes is increased the rate of execution of topology update procedure should be increased. Regarding that the execution of topology update procedure is an energy consuming task, precise adjustment of topology update interval is of high importance to increase the lifetime of the network. This problem could be expressed as:

What is the probability of disconnection

Increasing the mobility tolerance

As proved analytically, data loss ratio starts at 50% and grows incrementally. In order to suppress early link breakage, the buffer zone idea [23], [24] can be applied to the protocol. That is, the transmission ranges of the nodes are extended in order to cover the moving neighbors to some extent (Fig. 6). Using this simple approach no further change in the protocol structure is needed. In this case, transmission range (R) is greater than initial distance of the two nodes (r) and Rr is called

Energy optimization

Given a maximum acceptable loss ratio, there is a tradeoff between the value of buffer zone and topology update interval. As discussed earlier, a small value of buffer zone urges updating the topology more frequently in order to keep the loss ratio under the threshold. In this case radio transmission power is reduced but the overhead of control packets is increased. In this section, we provide a formulation for total power consumption in order to optimize the buffer zone given a maximum

Simulation results

In order to validate the analytic model provided in the previous sections a simulation scenario is provided here. Simulation program is developed in Xmulator [16] simulation framework. The simulation scenario has the same properties specified in Table 2 unless otherwise is stated. Number of nodes in each run is drawn from a Poisson distribution with density of Nnodes/6002 nodes per square meter, which gives average number of Nnodes nodes over the field. Then, the nodes are distributed with a

Conclusions

In this paper, a performance model is provided to study the effect of node mobility on the packet loss ratio of LEACH protocol, a well-known protocol for wireless sensor networks. As the LEACH protocol is an example of a more general idea of random clustering scheme, this study can be reused for other applications of random clustering. Preliminarily, spatial distribution of cluster heads and the random distance from cluster members to the cluster heads are evaluated analytically. Then, based on

Acknowledgment

The authors thank Mr. Kefayatipour for his collaboration for the simulation experiments.

Abbas Nayebi received the B.S. degree in hardware engineering from University of Tehran, Iran, in 1998 with first rank and received his M.Sc. in software engineering from Sharif University of Technology in 2001. He received his Ph.D. in computer engineering from Sharif University of Technology in August 2009. His research interest includes mobility tolerance analysis in wireless mobile networks, mobility modeling, sensor networks, mobile ad hoc networks, performance evaluation, interconnection

References (24)

  • K. Akkaya et al.

    A survey on routing protocols for wireless sensor networks

    Journal of Ad Hoc Networks

    (2005)
  • R. Krishnan et al.

    Efficient clustering algorithms for self-organizing wireless sensor networks

    Ad Hoc Networks

    (2006)
  • S. Bandyopadhyay, E.J. Coyle, An energy efficient hierarchical clustering algorithm for wireless sensor networks, in:...
  • T. Camp et al.

    A survey of mobility models for ad hoc network research

    Wireless Communications and Mobile Computing (WCMC)

    (2002)
  • S. Cho, J.P. Hayes, Impact of mobility on connection stability in ad hoc networks, in: IEEE WCNC,...
  • D.-S.K.Y.-J. Chung, Self-organization routing protocol supporting mobile nodes for wireless sensor network, in: Proc....
  • M.J. Handy, M. Haase, D. Timmermann, Low energy adaptive clustering hierarchy with deterministic cluster-head...
  • W.R. Heinzelman, A. Chandrakasan, H. Balakrishnan, Energy-efficient communication protocol for wireless microsensor...
  • W.B. Heinzelman et al.

    An application-specific protocol architecture for wireless microsensor networks

    IEEE Transactions on Wireless Communications

    (2002)
  • P. Juang, H. Oki, Y. Wang, M. Martonosi, L.-S. Peh, D. Rubenstein, Energy-efficient computing for wildlife tracking:...
  • G. Kumar, V. Paul, K. Jacob, Mobility metric based LEACH-Mobile protocol, in: Proc. of ADCOM 08,...
  • S. Lindsey, C.S. Raghavendra, PEGASIS: power-efficient gathering in sensor information systems, in: Proc. of IEEE...
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    Abbas Nayebi received the B.S. degree in hardware engineering from University of Tehran, Iran, in 1998 with first rank and received his M.Sc. in software engineering from Sharif University of Technology in 2001. He received his Ph.D. in computer engineering from Sharif University of Technology in August 2009. His research interest includes mobility tolerance analysis in wireless mobile networks, mobility modeling, sensor networks, mobile ad hoc networks, performance evaluation, interconnection networks and fault-tolerant systems. He has led several academic projects, e.g. XMulator simulation platform. He also participated in e-Cubes European project at LMTS laboratories of EPFL University, Switzerland and he made a research visit to LCN laboratory of KTH university, Sweden. He is a member of IEEE and ACM.

    Hamid Sarbazi-Azad received his B.Sc. in electrical and computer engineering from Shahid-Beheshti University, Tehran, Iran, in 1992, his M.Sc. in computer engineering from Sharif University of Technology, Tehran, Iran, in 1994, and his Ph.D. in computing science from the University of Glasgow, Glasgow, UK, in 2002. He is currently associate professor of computer engineering at Sharif University of Technology, and heads the IPM School of Computer Science, Tehran, Iran. His research interests include high-performance computer architectures, NoCs and SoCs, parallel and distributed systems, performance modeling/evaluation, graph theory and combinatorics, wireless/mobile networks, on which he has published more than 200 refereed conference and journal papers. He received Khwarizmi International Award in 2006, and TWAS Young Scientist Award in engineering sciences in 2007. He has served as the editor-in-chief for the CSI Journal on Computer Science and Engineering since 2005. He is an editorial board member, and a guest editor for several special issues on high-performance computing architectures and networks in related journals. Dr. Sarbazi-Azad is a member of ACM and CSI.

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