EZ-SEP: Extended Z-SEP Routing Protocol with Hierarchical Clustering Approach for Wireless Heterogeneous Sensor Network  
[PERSON]  
1 Faculty of Information Technology, L.N. Gumilyov Eurasian National University,  
Nur-Sultan CO 010000, Kazakhstan; [EMAIL_ADDRESS]  
1 Department of Communication Technology and Network, Universiti Putra Malaysia,  
Serdang 43400, Selangor, Malaysia  
2 Laboratory of Computational Science and Mathematical Physics, Institute of Mathematical  
Research (INSPEM), Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia  
define the physical environment in detail and control each other when they are selected as observers and combined with other nodes [6]. For efficient data acquisition, large-scale WSNs often need to be partitioned to improve the scalability, energy efficiency and load balancing [7]. Therefore, the unfolding of nodes is divided into two types: (1) a uniformly distributed field and (2) a randomly distributed field. In a uniformly distributed field, the nodes are systematically arranged in a predefined way [8], while in a randomly distributed field, the sensor nodes are randomly deployed in the area. In any case, due to the large number of nodes, network management issues such as connection management and fault detection become complex. In WSNs, the amount of nodes can exceed a hundred or even a couple of thousand, therefore, this number is too large for the base station to control them for the most efficient routing, or to place them in a specific location to program their location at each node. In addition, this kind of nodes are usually so small and cheap that they are not always equipped with GPS or optimized antennas. This means that collaboration is an important key to solving and ensuring \"low power consumption\" when delivering data to the base station. Indeed, these nodes will have to be able to communicate with each other, provided that there is no established network infrastructure and a predetermined location of the nodes [9]. The sensor node environment in the area of the wireless sensor network may be realized in two different ways: (1) uncontrolled environment and (2) controlled environment [10]. In an uncontrolled environment, sensor node location is not pre-defined, thus, the accessibility of a sensor node is hard to establish, so these nodes are not regularly monitored. In a controlled environment, on the other hand, every sensor node position is easily accessible and frequently monitored. The topology and infrastructure of a typical WSN consists of a base station and nodes located in a zone. Nodes sense events in an environment, process and aggregate data and then transmit it to a base station in direct or in multi-path mode, delivering records from one node to another in the network [11]. Nodes require high energy to deliver the sensed data to a base station if a message is sent directly, so their resources can be exhausted quickly. To solve this problem and extend the lifespan, data sensed is transferred from one node to the next and to the base station last, in multiple paths, so the energy consumption is reduced. Methods with multiple-sink have also been proposed to balance power consumption and reduce data transmission latency [12]. Energy efficiency is the most challenging task in wireless sensor networks. Therefore, the development of an energy-efficient routing algorithm makes the research work in this area very interesting. This and many more and more protocols such as LEACH [13] and its derived protocols, SEP [14], I-SEP [15], SEP-V [16] as well as all derivatives and enhanced forms of the SEP protocol, ESRA [17], HEED [18], and DEEC [19] are developed to increase network lifetime. Hierarchy methods have been also used to save the energy in sensor nodes. This method clusters the nodes, where data aggregation is performed on the cluster head (CH). Hierarchical routing protocols provide significant energy savings for WSNs.