We propose a clustering scheme for wireless sensor nodes in hierarchical wireless sensor networking architectures that employs mobile relay nodes in order to achieve energy conservation and network lifetime prolongation. The key aspects of our scheme are relay node relocation and reclustering when failures are detected. The performance of the proposed approach is evaluated via simulations for various topology layouts based on the sensor node population and number of mobile relay nodes employed. The results show significant energy savings in particular for topologies with large numbers of sensors. 1. Introduction Wireless sensor networks are becoming more and more popular nowadays due to the significant advantages they present in carrying out specialized monitoring tasks in certain application areas. These areas vary from military [1] and target tracking [2] to healthcare [3–5] and environmental monitoring [6–8]. However, there exist certain aspects that need to be addressed during deployment in order to achieve the best possible functionality and eliminate as much as possible problems that are inherent in wireless sensors technology and networking [9]. One of the most important design issues of a wireless sensor network that should be carefully treated is energy consumption and management that directly affects the network’s lifetime. Many research approaches have been proposed already as potential solutions to this problem. The suggested methods span from MAC layer algorithms [10–15] and topology control actions [16, 17] to hierarchical architectures that adopt the introduction of special purpose nodes, called relay nodes [18–20]. Research efforts on hierarchical architectures, also called two-tiered architectures, apart from introducing the role of a relay node (RN) or cluster head (CH), go further by applying clustering techniques that aim at minimizing the sensor communication cost [18, 21]. Several techniques have been proposed in the literature that aim to avoid rapid battery drainage that consequently may cause network connectivity failures or sensing area holes [22–25]. In single-hop operation of wireless sensor nodes (WSNs), data propagation towards the destination (i.e., the base station (BS)) that will further process the sensed data is accomplished by the relay nodes. Thus, in hierarchical deployments the critical factor is the lifetime achieved by the relay nodes which has to be enhanced as much as possible. Towards this, a measurable objective is the number of data gathering rounds that can be carried out by an RN. A data gathering round of
References
[1]
C. Schurgers and M. B. Srivastava, “Energy efficient routing in wireless sensor networks,” in Proceedings of the IEEE Military Communications Conference, Communications for Network-Centric Operations: Creating the Information Force (MILCOM '01), vol. 1, pp. 357–361, 2001.
[2]
X. Wang, J. J. Ma, S. Wang, and D. W. Bi, “Cluster-based dynamic energy management for collaborative target tracking in wireless sensor networks,” Sensors, vol. 7, no. 7, pp. 1193–1215, 2007.
[3]
S. Jiang, Y. Cao, S. Iyengar, et al., “CareNet: an integrated wireless sensor networking environment for remote healthcare,” in Proceedings of the ICST 3rd International Conference on Body Area Networks (ICST '08), pp. 9:1–9:3, Brussels, Belgium, 2008.
[4]
H. Alemdar and C. Ersoy, “Wireless sensor networks for healthcare: a survey,” Computer Networks, vol. 54, no. 15, pp. 2688–2710, 2010.
[5]
S.-L. Chen, H. Y. Lee, C. A. Chen, H. Y. Huang, and C. H. Luo, “Wireless body sensor network with adaptive low-power design for biometrics and healthcare applications,” IEEE Systems Journal, vol. 3, no. 4, pp. 398–409, 2009.
[6]
P. Corke, T. Wark, R. Jurdak, W. Hu, P. Valencia, and D. Moore, “Environmental wireless sensor networks,” Proceedings of the IEEE, vol. 98, no. 11, pp. 1903–1917, 2010.
[7]
H. Liu, Z. Meng, and M. Wang, “A wireless sensor network for cropland environmental monitoring,” in International Conference on Networks Security, Wireless Communications and Trusted Computing (NSWCTC '09), pp. 65–68.
[8]
F. Ingelrest, G. Barrenetxea, G. Schaefer, M. Vetterli, O. Couach, and M. Parlange, “SensorScope: application-specific sensor network for environmental monitoring,” ACM Transactions on Sensor Networks, vol. 6, no. 2, pp. 1–32, 2010.
[9]
I. Akyildiz, “Wireless sensor networks: a survey,” Computer Networks, vol. 38, pp. 393–422, 2002.
[10]
J.-H. Chang and L. Tassiulas, “Maximum lifetime routing in wireless sensor networks,” IEEE/ACM Transactions on Networking, vol. 12, no. 4, pp. 609–619, 2004.
[11]
H. Wang, N. Agoulmine, M. Ma, and Y. Jin, “Network lifetime optimization in wireless sensor networks,” IEEE Journal on Selected Areas in Communications, vol. 28, no. 7, pp. 1127–1137, 2010.
[12]
R. Braynard, A. Silberstein, and C. Ellis, “Extending network lifetime using an automatically tuned energy-aware MAC protocol,” Lecture Notes in Computer Science, vol. 3868, pp. 244–259, 2006.
[13]
X. Yang, T. Camp, H. Yang, and A. P. Petropulu, “Extending network lifetime for ALLIANCES,” Computer Communications, vol. 32, no. 17, pp. 1837–1851, 2009.
[14]
R. A. Rashid, W. M. A. E. W. Embong, A. Zaharim, and N. Fisal, “Development of energy aware TDMA-based MAC protocol for wireless sensor network system,” European Journal of Scientific Research, vol. 30, no. 4, pp. 571–578, 2009.
[15]
F. Na？t-Abdesselam, B. Bensaou, T. So？te, and K. L. Hung, “O-MAC: an organized energy-aware MAC protocol for wireless sensor networks,” in Proceedings of the IEEE International Conference on Communications (ICC '07), pp. 3648–3653, June 2007.
[16]
P. Santi, “Topology control in wireless ad hoc and sensor networks,” ACM Computing Surveys, vol. 37, no. 2, pp. 164–194, 2005.
[17]
Y. Wang, “Topology control for wireless sensor networks,” in Wireless Sensor Networks and Applications, Y. Li, M. T. Thai, and W. Wu, Eds., pp. 113–147., Springer, Boston, Mass, USA, 2008.
[18]
A. Bari, A. Jaekel, and S. Bandyopadhyay, “Clustering strategies for improving the lifetime of two-tiered sensor networks,” Computer Communications, vol. 31, no. 14, pp. 3451–3459, 2008.
[19]
O. Younis, M. Krunz, and S. Ramasubramanian, “Node clustering in wireless sensor networks: recent developments and deployment challenges,” IEEE Network, vol. 20, no. 3, pp. 20–25, 2006.
[20]
A. A. Abbasi and M. Younis, “A survey on clustering algorithms for wireless sensor networks,” Computer Communications, vol. 30, no. 14-15, pp. 2826–2841, 2007.
[21]
L. S. Jayashree, S. Arumugam, and N. Rajathi, “E2LBC: an energy efficient load balanced clustering technique for heterogeneous wireless sensor networks,” in IEEE IFIP International Conference on Wireless and Optical Communications Networks, pp. 1–7, 2006.
[22]
N. Dimokas, D. Katsaros, and Y. Manolopoulos, “Energy-efficient distributed clustering in wireless sensor networks,” Journal of Parallel and Distributed Computing, vol. 70, no. 4, pp. 371–383, 2010.
[23]
M. K. Watfa, O. Mirza, and J. Kawtharani, “BARC: a Battery Aware Reliable Clustering algorithm for sensor networks,” Journal of Network and Computer Applications, vol. 32, no. 6, pp. 1183–1193, 2009.
[24]
Y.-Y. W. Jie Jia, J. Chen, G. R. Chang, and Y. Y. Wen, “Efficient cover set selection in wireless sensor networks,” Acta Automatica Sinica, vol. 34, no. 9, pp. 1157–1162, 2008.
[25]
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, 2002.
[26]
K. Kalpakis, K. Dasgupta, and P. Namjoshi, “Maximum lifetime data gathering and aggregation in wireless sensor networks,” in Proceedings of the Joint International Conference on Wireless LANs and Home Networks (ICWLHN '02) and Networking (ICN '02), pp. 685–696, 2002.
[27]
Y. Yang, M. I. Fonoage, and M. Cardei, “Improving network lifetime with mobile wireless sensor networks,” Computer Communications, vol. 33, no. 4, pp. 409–419, 2010.
[28]
J. Rao and S. Biswas, “Network-assisted sink navigation for distributed data gathering: stability and delay-energy trade-offs,” Computer Communications, vol. 33, no. 2, pp. 160–175, 2010.
[29]
W. Alsalih, H. Hassanein, and S. Akl, “Placement of multiple mobile data collectors in wireless sensor networks,” Ad Hoc Networks, vol. 8, no. 4, pp. 378–390, 2010.
[30]
A. A. Somasundara, A. Kansal, D. D. Jea, D. Estrin, and M. B. Srivastava, “Controllably mobile infrastructure for low energy embedded networks,” IEEE Transactions on Mobile Computing, vol. 5, no. 8, pp. 958–972, 2006.
[31]
H. Li, S. Liu, and B. Hu, “Research on node sleep/wake-up mechanism in WSN based on energy threshold setting,” in Proceedings of the 5th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM '09), pp. 1–4, September 2009.
[32]
C. Y. Chang and H. R. Chang, “Energy-aware node placement, topology control and MAC scheduling for wireless sensor networks,” Computer Networks, vol. 52, no. 11, pp. 2189–2204, 2008.
[33]
T. Banerjee, B. Xie, J. H. Jun, and D. P. Agrawal, “Increasing lifetime of wireless sensor networks using controllable mobile cluster heads,” Wireless Communications and Mobile Computing, vol. 10, no. 3, pp. 313–336, 2010.
[34]
W.R. Heinzelman, A. Chandrakasan, and H. Balakrishnan, “Energy-efficient communication protocol for wireless microsensor networks,” in Proceedings of the 33rd Annual Hawaii International Conference on System Sciences, January 2000.
