GTS Allocation Analysis in IEEE 802.15.4 for Real-Time Wireless Sensor Networks
Ref: HURRAY-TR-051204 Publication Date: 1, Dec, 2005
GTS Allocation Analysis in IEEE 802.15.4 for Real-Time Wireless Sensor NetworksRef: HURRAY-TR-051204 Publication Date: 1, Dec, 2005
The IEEE 802.15.4 protocol proposes a flexible communication solution for Low-Rate Wireless Local Area Networks including sensor networks. It presents the advantage to fit different requirements of potential applications by adequately setting its parameters. When enabling its beacon mode, the protocol makes possible real-time guarantees by using its Guaranteed Time Slot (GTS) mechanism. However, power efficiency and real-time guarantees are two antagonist requirements in wireless sensor networks. This paper analyzes the performance of the GTS allocation mechanism in IEEE 802.15.4. The analysis gives a full understanding of the behavior of the GTS mechanism with regards to delay, throughput and power efficiency metrics. First, we propose two accurate models of service curves for a GTS allocation as a function of the IEEE 802.15.4 parameters. We then evaluate the delay bounds guaranteed by an allocation of a GTS using Network Calculus formalism. Finally, based on the analytic results, we analyze the impact of the IEEE 802.15.4 parameters on the throughput, delay and power efficiency of a GTS allocation. The results of this work pave the way for an efficient dimensioning of an IEEE 802.15.4 cluster.