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Advisor(s)
Abstract(s)
The hidden-node problem has been shown to be a major
source of Quality-of-Service (QoS) degradation in Wireless
Sensor Networks (WSNs) due to factors such as the limited
communication range of sensor nodes, link asymmetry and the
characteristics of the physical environment. In wireless
contention-based Medium Access Control protocols, if two
nodes that are not visible to each other transmit to a third
node that is visible to the formers, there will be a collision –
usually called hidden-node or blind collision. This problem
greatly affects network throughput, energy-efficiency and
message transfer delays, which might be particularly
dramatic in large-scale WSNs. This paper tackles the hiddennode
problem in WSNs and proposes H-NAMe, a simple yet
efficient distributed mechanism to overcome it. H-NAMe
relies on a grouping strategy that splits each cluster of a WSN
into disjoint groups of non-hidden nodes and then scales to
multiple clusters via a cluster grouping strategy that
guarantees no transmission interference between overlapping
clusters. We also show that the H-NAMe mechanism can be
easily applied to the IEEE 802.15.4/ZigBee protocols with
only minor add-ons and ensuring backward compatibility
with the standard specifications. We demonstrate the
feasibility of H-NAMe via an experimental test-bed, showing
that it increases network throughput and transmission success
probability up to twice the values obtained without H-NAMe.
We believe that the results in this paper will be quite useful in
efficiently enabling IEEE 802.15.4/ZigBee as a WSN protocol