Hybrid MAC Protocols for Low-Delay Scheduling
Avinash Mohan, Arpan Chattopadhyay, Anurag Kumar · 2016
We consider the Medium Access Control (MAC) problem in resource-constrained ad-hoc wireless networks typical of the Internet of Things (IoT). Due to the delay-sensitive nature of emerging IoT applications, there has been increasing interest in developing medium access control (TDMA) protocols in a slotted framework. The design of such MAC protocols must keep in mind the need for contention access at light traffic, and scheduled access in heavy traffic (leading to the long-standing interest in hybrid, adaptive MACs. In this paper, we consider the collocated node setting and require that each node acts autonomously only on the basis of locally available information. We propose EZMAC, a simple extension of ZMAC, and QZMAC which is designed using motivations from our extensions of certain delay-optimality and throughput-optimality theory from the literature. Practical implementation issues are outlined. Finally, we show, through simulations, that both protocols achieve mean delays much lower than those achieved by ZMAC and indeed, QZMAC provides mean delays very close to the minimum achievable in this setting, i.e., that of the centralized complete knowledge scheduler.