![](bga.png)
cific definition of QoS. However, it can be easily gen-
eralized in order to encompass other objective func-
tions or other constraints in the optimization process.
6 CONCLUSIONS
This paper has addressed the problem of energy effi-
cient QoS optimization in WSNs using cross-layering
techniques and exploiting a specifically introduced
caching platform. We have first presented the imple-
mentation of a caching solution based on a proxy node
which is in charge of answering, if a cached value is
available, to a request coming from a remote client
without transferring it to the WSN. Simulation results
show that the introduction of a caching architecture
has an impact in terms of energy saving on the system
performance, since it allows to reduce the transmis-
sions inside the WSN. Then, we have introduced an
optimization framework which, exploiting the infor-
mation collected by the RPL protocol and given a set
of constraints on the minimum and maximum values
of cache duration, allows to optimally configure the
values of the caching lifetimes. The proposed opti-
mization strategy allows to either find suitable solu-
tions in the presence of constraints on network life-
time or to find out the optimal non-dominated set of
solutions in the case of multi-objective optimization.
Further works include the real-time change of the
routing paths, in order to save the nodes which are
running out of energy, and large-scale experiments,
using the Senslab platform (Senslab Website, 2008),
in order to get real energy consumption data from
physical nodes.
ACKNOWLEDGEMENTS
This work is funded by the European Community’s
Seventh Framework Programme, area “Internetcon-
nected Objects”, under Grant no. 288879, CALIPSO
project - Connect All IP-based Smart Objects. The
work reflects only the authors’ views; the European
Community is not liable for any use that may be made
of the information contained herein.
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