Sink Mobility in Wireless Sensor Networks
School of Information Technology and Engineering, University of Ottawa, Ottawa, Canada K1N6N5
Data gathering is a fundamental task of wireless sensor networks (WSNs). It aims to collect sensor readings from sensory fields at predefined sinks (without aggregating at intermediate nodes) for analysis and processing. Research has shown that sensors near a data sink deplete their battery power faster than those far apart due to their heavy overhead of relaying messages. Nonuniform energy consumption causes degraded network performance and shortens network lifetime. Recently, sink mobility has been exploited to reduce and balance energy expenditure among sensors. The effectiveness has been demonstrated both by theoretical analysis and by experimental study. In this chapter, we investigate the theoretical aspects of the uneven energy depletion phenomenon around a sink, and address the problem of energy-efficient data gathering by mobile sinks. We present a taxonomy and a comprehensive survey of state of the art on the topic.