Achieving Minimum Latency in Multi-Hop MAC Protocol for Wireless Sensor Networks
Kien Trung Nguyen, Yusheng Ji · 2011
Achieving low latency and high energy efficiency are critical requirements in many of sensor network applications. Combining the duty cycling mechanism and multi-hop transmission is one of the solutions to this problem. Multi-hop protocols such as demand wakeup MAC (DW-MAC) schedule data transmissions during the sleep period. In so doing, a data packet can traverse multiple hops within a single operational cycle. By introducing a scheduling parameter, called proportional mapping function, DW-MAC can provide better performance in terms of both latency and energy efficiency, while avoiding data collision. In this paper, we derive the minimum value Rminof the scheduling function by numerically analyzing the delivery latency. Using that value, a DW-MAC-like protocol not only guarantees no collisions at the intended receivers but also achieves the minimum latency in the multi- hop scenario. In addition, we also show the upper and lower bounds of the delay. We evaluated the accuracy of our findings by running ns-2 simulations in multiple scenarios.