Int. J. Sensor Networks, Vol. 10, Nos. 1/2, 2011 25 Copyright © 2011 Inderscience Enterprises Ltd. HEEP (Hybrid Energy Efficiency Protocol) based on chain clustering Djallel Eddine Boubiche* and Azeddine Bilami Department of Computer Science, University of Batna, Batna, Algeria Email: dj.boubiche@gmail.com Email: abilami@yahoo.fr *Corresponding author Abstract: Wireless Sensor Networks have emerged as a new information-gathering system based on the collaborative efforts of large number of tiny sensors with limited resource. Energy constraints distinguish sensors networks from other wireless communication networks. Energy efficiency and network lifetime have been the focus of many research works on sensor networks, such as energy aware routing. This paper suggests a new routing protocol called HEEP which combines two algorithms: LEACH and PEGASIS. HEEP advise a new network self-organisation approach, that join clusters-based and the chain-based approaches. This new approach is called chains clustering approach. Organising the network nodes in chains clusters avoids the bad energy dissipation in LEACH protocol and reduces the routing delay generated by PEGASIS protocol. The experimental results show that HEEP outperforms LEACH and LEACH-C with more 110% of network lifetime, and reduces the routing delay introduced in PEGASIS by 50%. Keywords: WSN; wireless sensor network; energy efficiency; LEACH; PEGASIS; cluster-based approach; chain-based approach; chains clustering approach. Reference to this paper should be made as follows: Boubiche, D.E. and Bilami, A. (2011) ‘HEEP (Hybrid Energy Efficiency Protocol) based on chain clustering’, Int. J. Sensor Networks, Vol. 10, Nos. 1/2, pp.25–35. Biographical notes: Djallel Eddine Boubiche is currently a PhD student at the Department of Computer Science, University of Batna, Algeria. His research interests include wireless communication and sensor networks. Azeddine Bilami is currently serving as an Associate Professor at the Department of Computer Science, University of Batna, Algeria. His research interests are wireless and mobile networks, TCP/IP, internet, system-on-chip architectures, high-performance interconnects for parallel architectures and multiprocessors. 1 Introduction Wireless sensor networks (Akyildiz et al., 2002) have significant impact on many military and civil applications efficiency, such as battle field surveillance, security and disaster management. Minimising energy consumption and hence maximising the life time of the network are key requirements in the design of optimum sensor networking protocols and algorithms. Several routing protocols with different objectives have already been proposed for energy- efficient WSN applications. Among them, hierarchical routing (Ahmed et al., 2003) is regarded as being the most favourable approach in terms of energy effectiveness. Higher energy nodes can be used to process and send information while low-energy nodes can be used to perform the sensing in the proximity of the target. The powerful point of this kind of protocols is data aggregation (Al-Karaki et al., 2004) and fusion in order to decrease the number of messages transmitted to the sink (base station). Thus, it results a better saving of energy. Two large routing approaches use the hierarchical routing. First, a cluster-based organisation, and second a chain-based organisation. Our hybrid protocol combines the advantages of the two approaches while considering a formation of node chains within clusters. The remainder of this paper is organised as follows: Section 2 summarises the related work of LEACH, PEGASIS protocols and their variant. Section 3 describes our proposed algorithm and the highlights. In Section 4, we discuss the simulation environment and the obtained results showing the improvement of performances in terms of network lifetime, energy dissipation and routing delay. Finally, Section 5 concludes the paper. 2 Related work Indeed, two large algorithms namely LEACH (Low Energy Adaptive Clustering Hierarchy) (Heinzelman et al., 2000) and PEGASIS (Power-Efficient Gathering in Sensor Information