O-MAC: A Receiver Centric Power Management Protocol

Energy efficiency is widely understood to be one of the dominant considerations for wireless sensor networks. Based on historical data and technology trends, the receiver energy consumption will dominate all energy, to the point that for the majority of applications, power management research must focus on receiver efficiency. By modeling several popular MAC layer protocols, we derive bounds on performance for receiver efficiency. In particular, we analyze four abstract models, synchronous blinking (e.g. T- MAC, S-MAC), Long Preamble (e.g. B-MAC), structured time-spreading (also called asynchronous wake-up), and random time spreading. These results strongly suggest that scheduling the receiver so as to minimize (or eliminate) the potential for interference (or collisions) could be from 10 fold to 100 fold more efficient than current practice. We provide two new receiver scheduling methods, staggered on and pseudorandom staggered on, both of which are designed to exploit the untapped opportunity for greater receiver efficiency. Compared with the centralized deterministic scheduling in staggering on, the decentralized scheduling in pseudorandom staggered on achieves only slightly lower energy efficiency. In addition, we design a new MAC protocol, called O-MAC, based upon pseudorandom staggered on that achieves near optimal energy efficiency. Finally, we describe two variations of our O-MAC protocol-with local broadcast channel and preamble-sized slots.