Improving the IEEE 802.15.4 Slotted CSMA/CA MAC for Time-Critical Events in Wireless Sensor Networks

Anis Koubaa (1) , Mário Alves (1) , Bilel Nefzi (2) , Ye-Qiong Song (2)

1 IPP-HURRAY! Research Group [Porto]
2 TRIO - Real time and interoperability

In beacon-enabled mode, IEEE 802.15.4 is ruled by the slotted CSMA/CA Medium Access Control (MAC) protocol. The standard slotted CSMA/CA mechanism does not provide any means of differentiated services to improve the quality of service for timecritical events (such as alarms, time slot reservation, PAN management messages etc.). In this paper, we present and discuss practical service differentiation mechanisms to improve the performance of slotted CSMA/CA for time-critical events, with only minor add-ons to the protocol. The contribution of our proposal is more practical than theoretical since our initial requirement is to leave the original algorithm of the slotted CSMA/CA unchanged, but rather tuning its parameters adequately according to the criticality of the messages. We present a simulation study based on an accurate model of the IEEE 802.15.4 MAC protocol, to evaluate the differentiated service strategies. Four scenarios with different settings of the slotted CSMA/CA parameters are defined. Each scenario is evaluated for FIFO and Priority Queuing. The impact of the hiddennode problem is also analyzed, and a solution to mitigate it is proposed.

Mots clés: Wireless sensor network; Real-time; Performance; MAC protocol

Domaines: Réseaux et télécommunications [cs.NI]

Anis Koubaa, Mário Alves, Bilel Nefzi, Ye-Qiong Song. Improving the IEEE 802.15.4 Slotted CSMA/CA MAC for Time-Critical Events in Wireless Sensor Networks. Proceedings of the Workshop of Real-Time Networks (RTN 2006), Satellite Workshop to ECRTS 2006, Jean-Dominique Decotignie, Jul 2006, Dresden, Germany. ⟨inria-00114519⟩