Correlation of data sent by different sensors in a wireless sensor
network can be exploited during the data gathering process to improve
energy efficiency. In this paper, we study the energy efficiency of
correlation aware data aggregation trees under various sensor network
conditions and the tradeoffs involved in using them. The following two
related questions are specifically investigated in the study: (i) Is
there any practical limitation on the achievable improvement in energy
efficiency in adopting a correlation aware aggregation structure as
opposed to a correlation unaware structure? (ii) Is there a practically
maximum useable delay bound that can deliver the maximum achievable
improvement? In answering the above questions, we present comprehensive
simulation results and draw inferences based on the results. We also
conclude two rather surprising results that the energy improvement in
using correlation aware aggregation is not considerable under many
network scenarios, and the maximum useable delay bound is not
high compared with the delay along the maximum length shortest-path in
the default shortest
path tree.