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| 2.28 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
The recently standardized IEEE 802.15.4/Zigbee protocol stack offers great potentials for ubiquitous and
pervasive computing, namely for Wireless Sensor Networks (WSNs). However, there are still some open and
ambiguous issues that turn its practical use a challenging task. One of those issues is how to build a
synchronized multi-hop cluster-tree network, which is quite suitable for QoS support in WSNs. In fact, the
current IEEE 802.15.4/Zigbee specifications restrict the synchronization in the beacon-enabled mode (by the
generation of periodic beacon frames) to star-based networks, while it supports multi-hop networking using
the peer-to-peer mesh topology, but with no synchronization. Even though both specifications mention the
possible use of cluster-tree topologies, which combine multi-hop and synchronization features, the
description on how to effectively construct such a network topology is missing. This report tackles this
problem, unveils the ambiguities regarding the use of the cluster-tree topology and proposes two collisionfree
beacon frame scheduling schemes.