ABSTRACT
Contents 15.1 Introduction ....................................................................................................................418 15.2 Clustering in WSN ........................................................................................................ 420
15.2.1 Clustering Requirement .......................................................................................421 15.2.2 Cluster Formation ............................................................................................... 422 15.2.3 Cluster Maintenance ........................................................................................... 422 15.2.4 Factors Affecting Clustering ............................................................................... 422
15.2.4.1 Network Architecture ......................................................................... 422 15.2.4.2 Deployment of Nodes ......................................................................... 423 15.2.4.3 Data Processing .................................................................................. 423 15.2.4.4 Load Balancing ................................................................................... 423 15.2.4.5 Fault Tolerance ................................................................................... 423 15.2.4.6 Increased Connectivity and Reduced Delay ........................................ 424 15.2.4.7 Minimal Cluster Count ...................................................................... 424 15.2.4.8 Maximizing Network Longevity ......................................................... 424 15.2.4.9 Scalability ........................................................................................... 424 15.2.4.10 Hardware Constraints ........................................................................ 425
15.3 Protocol Overview.......................................................................................................... 425 15.3.1 LEACH .............................................................................................................. 425
15.3.1.1 Advertising Phase ................................................................................ 426 15.3.1.2 Cluster Setup Phase ............................................................................ 426 15.3.1.3 Schedule Creation ............................................................................... 426 15.3.1.4 Data Transmission .............................................................................. 426
15.3.2 Hybrid, Energy-Efficient, Distributed Clustering ............................................... 427 15.3.2.1 Initialization Phase ............................................................................. 427
416
15.1 Introduction Wireless sensor network (WSN) refers to a group of spatially dispersed and dedicated sensors for monitoring and recording the physical conditions of the environment and organizing the collected data at a central location. WSNs measure environmental conditions such as temperature, sound, pollution levels, humidity, wind speed and direction, pressure, illumination intensity, vibration intensity, power line voltage, chemical concentrations, and vital body functions. WSNs provide reliable monitoring from faraway distances. These networks are basically data-gathering networks in which data are highly correlated and the end user needs a high-level description of the environment by the sensing nodes. It emerged due to advancements in micro-electromechanical systems and digital electronics, which enabled the development of low-cost, low-power, multifunctional sensors that are small in size and communicate in short distances [1]. Initially, it was used in military operations for surveillance activity on borders, although nowadays WSNs span a huge area of implementations.
