Coverage in wireless sensor networks (WSNs)
is a well-studied problem. In most of the situation WSNs
have two-dimensional bounded continuous domain. In
practice, sensors usually dropped randomly from air on
previously determined points (called, vertices) of the
domain (called Region of Interest or simply ROI). But
since the deployment is random in manner the sensors
will not place on the target vertices in most of the times.
Hence ROI will not cover by the deployed sensors. The
question is, how we reduced the area which is not covered
by the sensors? Usually, extra sensors are dropped on
some randomly chosen vertices to minimize the
uncovered area. In our previous work we developed an
alternative strategy, we reduced the distance between two
adjacent vertices and drop exactly one sensor on each
vertex. The amount of reduction depends on the number
of extra sensors used. In that paper we compare
uncovered area for the two strategies (the old one and the
alternative one), for two distributions (uniform and
normal), and for several number of excess sensors.
Simulation result shows that alternative strategy is better
for lower variance of the randomness but old one is better
for higher variance. In this paper, we partitioned the ROI
in regular hexagons and develop a new strategy, which is
mixing of the above two strategies, for deployment of
extra sensors. We divide the total number of extra sensors
in two parts. One part is used for reducing the distance
between the two adjacent vertices and other parts is used
for deploying two sensors on some randomly selected
vertices. Simulation results suggest the proper balancing
between these two parts with respect to the variance of
two distributions (uniform and normal).
Keywords : Sensor Coverage; Wireless Sensor; Sensor Networks; Random Deployment.