Maximizing network-lifetime in large scale heterogeneous wireless sensor-actor networks: a near-optimal solution

Delay and energy constraints have a significant impact on
the design and operation of wireless sensor-actuator networks.
We cosider a wireless sensor-actuator network, consisting
of large number of sensors and few actuators, in which
both energy and delay are hard constraints and must be
jointly optimized.
In this paper, we propose that each sensor node must
transmit its data to only one of the actuators. To maximize
the network lifetime and attain minimum end-to-end
delays, it is essential to optimally match each sensor node to
an actuator and nd an optimal routing scheme. We model
the actuator selection and optimal
ow routing as joint optimization
problem, which is NP-hard in general. Therefore,
we use a relaxation technique and provide a distributed solution
for optimal actuator selection subject to energy and delay
constraints. Further, once the destination actuators are
xed, we provide an optimal
ow routing solution with the
aim of maximizing network lifetime. We then propose to use
a delay-energy aware TDMA based MAC protocol in compliance
with the routing algorithm. The optimal routing and
TDMA MAC schemes together guarantees a near-optimal
lifetime. The proposal is validated by means of analysis and
ns-2 simulation results.