A Network Stability Monitoring Mechanism of Cluster-Oriented Wireless Sensor Network

ABSTRACT In wireless sensor network (WSN), every sensor node could active dynamically. Therefore, those sensor nodes will affect the stability of network topology because of clustering and de-clustering, and continuously make reconfiguration for the clusters of wireless sensor network, all that will influence the overall function of network. It is an important issue that how to elect a cluster manager (CM) to keep the stability of network topology. In addition, large amount of events maybe flood suddenly in a local area. Such the case might raise the overload of CM, even lead CM to fail or crash and the WSN topology maybe self-organized. However, a mechanism needs to be considered that allows coping with the additional loads and can balance the workload of CM. In this study, a preventable and supportable monitor mechanism to avoid CM overload cause network unstable and to reduce load imbalance problem is proposed. Hence, it can prolong lifetime of network and raise performance of network efficiently. INTRODUCTION With the explosion of wireless network, the activity of mankind has been impacted, in the infrastructure network structure; the medium for fixing center will be regarded as the relay station to bringing about the connection of two mobile equipments, so that the data is transmitted (Akyildiz, Weilian, Sankarasubramaniam, & Cayiric, 2002). The relay station, such as Access Point (AP), was given an excellent feature to control the position of mobile equipments, which is just the same as the router. But these equipments are usually damaged by the extrinsic factors such as the war, natural disasters, etc., which will cause the failure connection between the nodes, therefore, the traditional wireless network has failed to meet the needs of mankind (CM, 2003). In recent years, the advance of technology and rapid development of Micro-Electro-Mechanical Systems (MEMS) have facilitated the rapid growth of non-infrastructure network structure, in which, Wireless Sensor Networks (WSNs) is purposed to be free to gain information at anytime and anywhere under a non-infrastructure network structure for meeting the needs of mankind (Akkaya & Younis, 2005; Heinzelman, Chandrakasan & Balakrishnan, 2002; Laerhoven, Lo & Ng, 2004; Lindsey & Ragavenda, 2002; Mhatre, Rosenberg, Kofman, Mazumdar & Shroff, 2004; Shen, Zhang, & Zhong, 2006; Younis & Fahmy, 2004). Therefore, variety of applications in WSNs are paid attention and developed. There are typically four kinds of applications such as the environment observation, military, building and healthcare monitoring, etc. in WSNs. Environmental observation includes: 1) to detect and examine the water quality near the chemical factory whether the water is polluted; 2) to detect and examine the forest fire and put forward a alarm when the forest fire is happened; 3) the pollution of the air is monitored; 4) to obtain humidity, pressure and temperature, etc. in specific ecological environment and track the whereabouts of the rare animals. Due to characteristics of WSNs (the rapid deployment, self-organization, and fault tolerance etc.), more apply to track the positions of combat tank and intelligence of enemy in the battlefield quickly and contiguously. Military monitoring is the first idea at applications of WSNs. By building monitoring (BA, 2006), old buildings may endanger householders' safety due to structure of the buildings that are happened some changes. These changes can be detected and examined; WSNs allow a non-invasive means of monitoring and diagnosing moisture and slant levels, pollutants or gas detection to ensure safety, comfort and regulatory compliance in buildings. In healthcare monitoring (Lindsey & Raghavenda, 2002), wireless physiological sensors which wearable and implantable two kinds of types are used to measure the status of the patient. Viewed in this light, WSNs can offer many valuable applications. …