Funneling-MAC: A Localized, Sink Oriented MAC for Boosting Fidelity
in Sensor Networks
*
The funneling-MAC, developed as part of
the Armstrong
Project, is a hybrid TDMA/CSMA
protocol to mitigate the funneling effect, which is present in choke
points in wireless sensor networks.
Abstract Sensor
networks exhibit a unique funneling effect which is a product of the
distinctive many-to-one, hop-by-hop traffic pattern found in sensor
networks,
and results in a significant increase in transit traffic intensity,
collision,
congestion, packet loss, and energy drain as events move closer toward
the
sink. While network (e.g., congestion control) and application
techniques
(e.g., aggregation techniques) can help counter this problem they
cannot fully
alleviate it. We take a different but complementary approach to solving
this
problem than found in the literature and present the design,
implementation,
and evaluation of a localized, sink-oriented, funneling-MAC
capable of mitigating the funneling effect and
boosting application fidelity in sensor networks. The funneling-MAC is
based on
a CSMA/CA being implemented network-wide, with a localized TDMA
algorithm
overlaid in the funneling region (i.e., within a small number of hops
from the
sink). In this sense, the funneling-MAC represents a hybrid MAC
approach but
does not have the scalability problems associated with the network-wide
deployment of TDMA. The funneling-MAC is 'sink-oriented' because the
burden of
managing the TDMA scheduling of sensor events in the funneling region
falls on
the sink node, and not on resource limited sensor nodes; and it is
'localized'
because TDMA only operates locally in the funneling region close to the
sink and
not across the complete sensor field. We show through experimental
results from
a 45 MICA-2 testbed that the funneling-MAC mitigates the funneling
effect,
improves throughput, loss, and energy efficiency, and importantly,
significantly out performs other representative protocols such as
B-MAC, and
more recent hybrid TDMA/CSMA MAC protocols such as Z-MAC. * This
work is supported by the Army Research Office (ARO) under
Award
W911NF-04-1-0311 on resilient sensor networks.
People
- Funneling-MAC Technical
Report including more extensive results and an analitycal
fundation of
the Funneling-MAC algorithm
which dynamically tunes the depth of the intensity region.
Funneling-MAC
TinyOS code 0.1.0
NEW!!
The Funneling-MACcode
is now also available inside the 'contrib' directory of the tinyos-1.x
source tree so you can obtain it
directly from SourceForge
CVS.
The
Funneling-MAC tinyos package is available here.
The Funneling-MAC code currently runs only on Mica2 motes and
tinyos-1.x. To use the
package follow the instructions below:
2. untar the package using the following command: $ tar xzvf
tinyos-1.x-funnelingMAC.tgz
3. you should see a directory named 'tinyos-1.x-funnelingMAC'.
This directory can be placed anywhere you have access in the filesystem
4. Read and follow the instructions in the README
inside the 'tinyos-1.x-funnelingMAC'
directory.
For our internal record please provide
the information below after having downloaded the funneling-MAC
package.
This information will not
be disclosed and the confidentiality of the
data you provide to us will be maintained.