  The increasing demand for real-time applications has made the Quality of
Service (Qos) support for wireless sensor networks (WSN) a fairly new research
framework. In this paper, we propose an extended model of the Beacon enabled
IEEE 802.15.4 including the Guaranteed Time Slot GTS allocation mechanism in
the aim to analyze and evaluate network performances. Series of extensive
simulations were performed to analyze the impact of the Beacon Order BO and the
Superframe Order SO on the network performance based on commonly known metrics.
In particular, we examine data packet delivery performance and the throughput
for different duty cycle rates. Also, we analyze the impact of the number of
nodes on collision probability. Thus, for high number of nodes, collision
becomes higher and the reachability begins to decline slightly. We discuss and
compare simulation results conducted under various parameter settings to the
IEEE 802.11 network.
