FROG-MAC: A Fragmentation Based MAC Scheme for Prioritized Heterogeneous Traffic in Wireless Sensor Networks

Abstract

In most scenarios of wireless sensor networks (WSNs), different traffic types have specific service requirements. None of the previous MAC schemes has been able to provide true pre-emption to the high priority data. This paper introduced a novel data fragmentation scheme for low priority traffic in order to improve the delay performance of high priority traffic in WSN. It is proposed that instead of transmitting the low priority packet as a single unit, it should be transmitted in small fragments with pauses. A MAC protocol FROG-MAC has been designed based on the proposed fragmentation scheme. Simulations over Contiki operating system and testbed experiments over TelosB/Tmote Sky Platform have been performed to evaluate performance of FROG-MAC based on parameters of delay and throughput/packet delivery ratio (PDR). It has been found that FROG-MAC improves the delay and throughput of urgent traffic by reducing its waiting time. For increase in the fragment size, the delay of urgent traffic increases, whereas that of normal traffic reduces. With the increasing network size, the delay for both traffic types increases, and PDR reduces due to the increased network traffic load, collision and retransmissions. The performance of FROG-MAC has also been compared against energy-efficient multi-constrained QoS aware MAC.