PEGASIS
PEGASIS (Power-Efficient GAthering in Sensor Information Systems) is a protocol designed for energy-efficient communication in wireless sensor networks. Proposed in 2002 as an evolution of cluster-based approaches, PEGASIS organizes sensor nodes into a linear chain so that each node communicates only with a close neighbor. Data are aggregated along the chain and a designated chain leader transmits the fused information to the base station; leadership is rotated to balance energy consumption.
Operation typically involves two phases: chain formation and data transmission. Chain formation is commonly performed with
PEGASIS advantages include reduced total transmissions, lower per-round energy use compared with flat or cluster-only schemes,