Asynchronous wakeup for ad hoc networks

Due to the slow advancement of battery technology, power management in wireless networks remains to be a critical issue. Asynchronous wakeup has the merits of not requiring global clock synchronization and being resilient to network dynamics. This paper presents a systematic approach to designing and implementing asynchronous wakeup mechanisms in ad hoc networks. The optimal wakeup schedule design can be formulated as a block design problem in combinatorics. We propose a neighbor discovery and schedule bookkeeping protocol that can operate on the optimal wakeup schedule derived. Two power management policies, i.e. slot-based power management and on-demand power management, are studied to overlay desirable communication schedule over the wakeup schedule mandated by the asynchronous wakeup mechanism. Simulation studies indicate that the proposed asynchronous wakeup protocol is quite effective under various traffic characteristics and loads: energy saving can be as high as 70%, while the packet delivery ratio is comparable to that without power management.