IEEE SENSORS JOURNAL, VOL. 16, NO. 1, JANUARY 1, 2016 137 A Fuzzy Logic-Based Clustering Algorithm for WSN to Extend the Network Lifetime Padmalaya Nayak, Member, IEEE, and Anurag Devulapalli Abstract— Wireless sensor network (WSN) brings a new paradigm of real-time embedded systems with limited compu- tation, communication, memory, and energy resources that are being used for huge range of applications where the traditional infrastructure-based network is mostly infeasible. The sensor nodes are densely deployed in a hostile environment to monitor, detect, and analyze the physical phenomenon and consume con- siderable amount of energy while transmitting the information. It is impractical and sometimes impossible to replace the battery and to maintain longer network life time. So, there is a limitation on the lifetime of the battery power and energy conservation is a challenging issue. Appropriate cluster head (CH) election is one such issue, which can reduce the energy consumption dramatically. Low energy adaptive clustering hierarchy (LEACH) is the most famous hierarchical routing protocol, where the CH is elected in rotation basis based on a probabilistic threshold value and only CHs are allowed to send the information to the base station (BS). But in this approach, a super-CH (SCH) is elected among the CHs who can only send the information to the mobile BS by choosing suitable fuzzy descriptors, such as remaining battery power, mobility of BS, and centrality of the clusters. Fuzzy inference engine (Mamdani’s rule) is used to elect the chance to be the SCH. The results have been derived from NS-2 simulator and show that the proposed protocol performs better than the LEACH protocol in terms of the first node dies, half node alive, better stability, and better lifetime. Index Terms— WSN, SCH, fuzzy logic. I. I NTRODUCTION W IRELESS Sensor Network considered as real time embedded system deployed in a particular region to sense various types of environmental parameters such as temperature, pressure, gas, humidity etc. The huge applica- tions of WSN like habitant monitoring, forest fire detection, surveillances, transport monitoring etc. have created a lot of interest among the researcher community in recent past. Typically, WSNs are densely deployed in hazardous places where battery recharge or replacement is nearly impossible and human monitoring scheme is highly risky. There are many typical issues such as power con- straints, limited computing capacity, open environment; radio Manuscript received July 20, 2015; revised August 13, 2015; accepted August 13, 2015. Date of publication August 25, 2015; date of current version December 10, 2015. The associate editor coordinating the review of this paper and approving it for publication was Dr. M. N. Abedin. P. Nayak is with the Department of Information Technology, Gokaraju Rangaraju Institute of Engineering and Technology, Hyderabad 500090, India (e-mail: padma_nayak@yahoo.com). A. Devulapalli was with the Department of Information Technol- ogy, Gokaraju Rangaraju Institute of Engineering and Technology, Hyderabad 500090, India. He is now with the System Testing Department, TCS, Mumbai 400 614, India (e-mail: anurag.dev@hotmail.com). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/JSEN.2015.2472970 Fig. 1. General System Model for clustered WSN. connectivity makes the sensor nodes faulty many times. Once the network is established, nodes keep on sensing the infor- mation and the battery power goes exponentially. Whenever the nodes detect any event, they send the information to the other nodes or to the base station. Sometimes it happens that the same information received by nearby sensor nodes can be received by the base station that makes the network inefficient. To avoid this data redundancy and to make the network most energy efficient, data aggregation and sensor fusion have been emphasized in the literature [1]. Many routing protocols with many different ideas have been proposed in the literature to make the network energy efficient [14]. Cluster based routing protocol is one of these efficient ideas, where sensor nodes are divided into number of groups and each group is called as a cluster. One group leader is elected in each cluster known as Cluster Head (CH). Data aggregation is obtained at the leader node. The leader node/CH is only responsible for sending the message to the BS. Figure 1 shows the general system model for clustering based WSN. LEACH [1], [2] is the first famous hierarchical routing protocol which is proven to be most efficient over traditional routing protocol. In LEACH, the CH is elected in a proba- bilistic manner and tries to balance the load at each sensor node in a rotation basis. Even though many studies present the efficiency of LEACH protocol, it has certain pitfalls that need to be discussed. As LEACH relies on probabilistic value, it might happen that in each round more than one cluster heads are elected or no cluster head is elected. Further, the 1530-437X © 2015 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information.