30-03-2012, 04:09 PM
A Performance Aware Congestion Control Algorithm in Wireless Sensor Networks
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INTRODUCTION
Wireless Sensor Networks (WSNs) are wireless networks
consisting of spatially distributed autonomous devices using
sensors to cooperatively monitor physical or environmental
conditions, such as temperature, sound, vibration, pressure,
motion, or pollutants, at different locations [1]. Sensor nodes
are low cost, light-weight, tiny devices with energy constraints.
Frequently, sensor nodes are densely deployed near the event
sources and sinks in a redundant manner [2]. Since power is
a severe limitation for these nodes, dense deployment assists
in the networks’ robust operation (e.g. due to node or link
failure) and significantly contributes in the overall network
performance. Congestion happens when the offered load is
more than the available capacity of the network. Currently
there are two ways to face congestion.
II. RELATED WORK
Resource control as method for congestion control and
avoidance as well as for reliable data transmission in WSNs
has not attracted a lot of attention. Some notable efforts are
presented below.
TARA (Topology Aware Resource Adaptation) [3] protocol
focuses on the adaptation of network’s extra recourses in
case of congestion, alleviating intersection hot spots. TARA
copes with buffer occupancy as well as channel loading. In
TARA, congestion alleviation is performed with the assistance
of two important nodes. These are the distributor and the
merger nodes. Between them a “detour path” is established
starting at the distributor and ending at the merger.
III. DYNAMIC ALTERNATIVE PATH SELECTION SCHEME
DESCRIPTION
DAlPaS is a congestion control and avoidance algorithm
that attempts to choose an alternate path in case of congestion
taking into account a number of basic performance parameters.
Complementary to Energy Aware Protocols [14][15] that find
the lowest energy route or energy sufficient paths to forward
data and base their path alternation decision on these conditions,
DAlPaS also takes into consideration the node’s congestion
situation (both in terms of buffer occupancy and channel
interference).
V. CONCLUSIONS AND FUTURE WORK
In this paper we propose a novel Congestion Control and
avoidance algorithm called DAlPaS (Dynamic Alternative Path
Selection) which is able to uniformly utilize network resources
(sensor’s node power), while, at the same time maintain
robust and reliable data delivery. The strength of the proposed
algorithm is that it does the work correctly, with simplicity, and
with improved performance.