DESIGN OF AN ENERGY EFFICIENT MAC PROTOCOL FOR SINK BASED WIRELESS SENSOR NETWORKS
Kiran Tatapudi · 2006
Wireless sensor networks (WSN) can operate in demanding environments and provide clear benefits in cost, power and flexibility. But the success of such networks depends on their robustness and energy efficiency which in-turn are influenced by the Medium access control (MAC) mechanism. MAC protocols based on Carrier Sense Multiple Access (CSMA) provide a simple and robust solution but suffer from collisions and energy wastage. On the other hand Time Division Multiple Access (TDMA) mechanism is inherently energy efficient and collision-free. However the protocols based on TDMA incur large overhead in generating and maintaining time-schedules. Moreover, the schedules generated based on the assumption that communications which are beyond two-hops do not interfere are not truly collision free. This is because in an environment with obstacles, asymmetric links and link variations the assumption is not valid. In this thesis we propose Bulk Synchronous Medium Access (BSMA), an energy efficient TDMA algorithm for sink-based WSNs which uses a “try and verify” approach as opposed to the “speculation” approach used by other TDMA algorithms.