  We study the heterogeneous wireless sensor networks (WSNs) and propose the
necessary condition of the optimal sensor deployment. Similar to that in
homogeneous WSNs, the necessary condition implies that every sensor node
location should coincide with the centroid of its own optimal sensing region.
Moreover, we discuss the dynamic sensor deployment in both homogeneous and
heterogeneous WSNs with limited communication range for the sensor nodes. The
purpose of sensor deployment is to improve sensing performance, reflected by
distortion and coverage. We model the sensor deployment problem as a source
coding problem with distortion reflecting sensing accuracy. Traditionally,
coverage is the area covered by the sensor nodes. However, when the
communication range is limited, a WSN may be divided into several disconnected
sub-graphs. Under such a scenario, neither the conventional distortion nor the
coverage represents the sensing performance as the collected data in
disconnected sub-graphs cannot be communicated with the access point. By
defining an appropriate distortion measure, we propose a Restrained Lloyd (RL)
algorithm and a Deterministic Annealing (DA) algorithm to optimize sensor
deployment in both homogeneous and heterogeneous WSNs. Our simulation results
show that both DA and RL algorithms outperform the existing Lloyd algorithm
when communication range is limited.
