Abstract:
We
investigate the following fundamental question - how
fast can information
be collected from a wireless sensor network organized as tree? To address
this, we explore and evaluate a number of different techniques using realistic
simulation models under the many-to-one communication paradigm known as
converge cast. We first consider time scheduling on a single frequency channel
with the aim of minimizing the number of time slots required (schedule length)
to complete a converge cast. Next, we combine scheduling with transmission
power control to mitigate the effects of interference, and show that while
power control helps in reducing the schedule length under a single frequency,
scheduling transmissions using multiple frequencies is more efficient. We give
lower bounds on the schedule length when interference is completely
eliminated, and propose algorithms that achieve these bounds. We also
evaluate the performance of various channel assignment methods and find
empirically that for moderate size networks of about 100 nodes, the use of
multi-frequency scheduling can suffice to eliminate most of the interference.
Then, the data collection rate no longer remains limited by interference but by
the topology of the routing tree. To this end, we construct degree-constrained
spanning trees and capacitated minimal spanning trees, and show significant
improvement in scheduling performance over different deployment densities.
Lastly, we evaluate the impact of different interference and channel models on
the schedule length.
be collected from a wireless sensor network organized as tree? To address
this, we explore and evaluate a number of different techniques using realistic
simulation models under the many-to-one communication paradigm known as
converge cast. We first consider time scheduling on a single frequency channel
with the aim of minimizing the number of time slots required (schedule length)
to complete a converge cast. Next, we combine scheduling with transmission
power control to mitigate the effects of interference, and show that while
power control helps in reducing the schedule length under a single frequency,
scheduling transmissions using multiple frequencies is more efficient. We give
lower bounds on the schedule length when interference is completely
eliminated, and propose algorithms that achieve these bounds. We also
evaluate the performance of various channel assignment methods and find
empirically that for moderate size networks of about 100 nodes, the use of
multi-frequency scheduling can suffice to eliminate most of the interference.
Then, the data collection rate no longer remains limited by interference but by
the topology of the routing tree. To this end, we construct degree-constrained
spanning trees and capacitated minimal spanning trees, and show significant
improvement in scheduling performance over different deployment densities.
Lastly, we evaluate the impact of different interference and channel models on
the schedule length.
Algorithm used:
1.
BFS TIME SLOT ASSIGNMENT
2. LOCAL-TIME SLOT ASSIGNMENT
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