Dynamic channel reservations for wireless multihop communications

Providing real-time service in an energy efficient manner in wireless multihop networks is an important and challenging problem. However, existing medium access control schemes are either over-coordinated (fixed-schedule-based schemes) or under-coordinated (prioritized contention-based schemes), failing to address this problem efficiently. This paper introduces a new medium access scheme, called FrugalMAC, aiming to provide timely, ondemand, and contention-free medium access by relying on a progressive, dynamic reservation mechanism coupled with reservation vectors. A node sleeps whenever the channel is not needed for data communication and slot reservation. In addition, FrugalMAC employs reservation pipelining and an admission control mechanism to support end-to-end real-time stream delivery. We have implemented a prototype of FrugalMAC in our sensor network testbed. Our preliminary results show that FrugalMAC has high energy efficiency and effectively supports timeliness.