International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 12 | Dec 2019 www.irjet.net p-ISSN: 2395-0072 © 2019, IRJET | Impact Factor value: 7.34 | ISO 9001:2008 Certified Journal | Page 713 A Review on Cluster-based Routing for Wireless Sensor Network MAHMOUD BADAWY 1 , MONA MOUSTAFA 1 , HESHAM ARAFAT ALI 1 , AND YOUSRY ABDULAZEEM 2 1 Department of Computer Engineering and Systems, Faculty of Engineering, Mansoura University, Mansoura 35516, Egypt. 2 Computer Engineering Department, Misr Higher Institute for Engineering and Technology, Mansoura 35516, Egypt. ---------------------------------------------------------------------***---------------------------------------------------------------------- Abstract - Recently, the use of distributed sensing applications is a major trend glared at the emergence of low-power embedded systems and wireless networking. These technologies directed to the implementation of wireless sensor networks (WSN). Although WSN has offered unique opportunities to set the foundation for using ubiquitous and pervasive computing, it suffered from several issues and challenges such as frequently changing network topology and congestion issues which affect not only network bandwidth usage but also performance. In this paper, we survey the energy-efficient hierarchical routing protocols, developed from conventional LEACH routing protocol. The focus of this study is how these extended protocols work to increase the lifetime and the quality of WSNs. Furthermore, this paper also highlights some issues and challenges of the LEACH protocol and its variants. Additionally, this paper explores how these issues are tackled by extended versions of LEACH. We compare the features and performance issues of the selected hierarchical routing protocols. Key Words: WSN, Clustering, Routing, QoS, LEACH. 1. INTRODUCTION Wireless Sensor Network (WSNs) is a group of sensor nodes that can sense the physical phenomenon of any environment like humidity, temperature, pressure, speed, and others. Also, they can communicate together to send their sensed data to a specific gateway to achieve a monitor of a specific environment. Figure 1 shows the architecture of WSN. Fig -1: WSN architecture WSNs attract the attention of many researchers. As WSNs promises lots of benefits in terms of range, cost, and flexibility As shown in Figure 2, WSNs are used for numerous applications such as traffic and video control, habitat monitoring, security, agriculture, medical and health care, industrial automation, entertainment, transportation, smart grid, control systems, military reconnaissance, disaster management [1]. Since plentiful sensors are usually deployed in remote and inaccessible places, the deployment and maintenance should be easy and scalable. Fig -2: A set of smart applications dependent on WSN. The future Internet, designed as an “Internet of Things,” (IoT) is foreseen to be “a world-wide network of interconnected objects uniquely addressable, based on standard communication protocols”. Recently, due to the growth of an IoT technology, Ericsson and Cisco forecast estimate the connected devices (i.e. Tablet, cell phones, etc.) such as smart city, intelligent transportation, environmental monitoring, and home automation will reach approximately 50 billion devices in 2020 [REF], and the data produced by these devices will reach 500 zettabytes as shown in Figure 3. Nowadays, IoT is relied upon to have an important life-care and business processes to add personal satisfaction and to develop the world's economy. WSNs are Things (sensor nodes) connected without a wire to gather some data. IoT is a WSN embedded in a Physical object (Thing) that are addressed by IP address to be able to communicate over the Internet to perform specific functions for applications. Thus, WSN is like the eyes and ears of the IoT. The IoT in a broad sense is like a brain. With the emerging technology of IoT, the number of applications of WSN increases every day. In general, WSN composed of nodes and sink (Base station) as shown in Figure 4. Nodes are small devices that collect and transmit data about the surrounding environment. WSN nodes consist of several functional modules: sensing unit, processing unit, storage unit, Transceiver unit, power unit, power generator, Location finding system, and Mobilize, as in Figure 5. Sink (base