DSA: Distributed Semi-Asynchronous Sleep Scheduling Protocol for Mobile Wireless Networks

A synchronization error is unavoidable in mobile wireless multihop networks, especially in sparse networks, due to the lack of effective synchronization algorithms. Fortunately, some level of clock synchronization is possible among nodes. In this paper, we propose a distributed semi-asynchronous sleep scheduling protocol (DSA) considering loosely synchronized clocks in sparse mobile wireless networks. The sleep schedules are constructed to guarantee contacts among distributed nodes having synchronization errors. Also, the protocol can be optimized using the distribution of the synchronization error to maximize the energy efficiency. With simulation results, we demonstrate that the DSA can achieve higher energy efficiency than existing asynchronous sleep scheduling protocols, especially for large synchronization errors.