SCADDS: Scalable
Coordination A
rchitectures for Deeply
Distributed Systems
Sensor-MAC (S-MAC): Medium Access Control for Wireless Sensor Networks
S-MAC is a medium-access control (MAC) protocol designed for wireless sensor
networks. Wireless sensor networks use battery-operated computing and sensing
devices. A network of these devices will collaborate for a common application
such as environmental monitoring. We expect sensor networks to be deployed
in an ad hoc fashion, with individual nodes remaining largely inactive for
long periods of time, but then becoming suddenly active when something is
detected. These characteristics of sensor networks and applications motivate
a MAC that is different from traditional wireless MACs such as IEEE 802.11
in almost every way: energy conservation and self-configuration are primary
goals, while per-node fairness and latency are less important.
S-MAC uses three novel techniques to reduce energy consumption and support
self-configuration. To reduce energy consumption in listening to an idle channel,
nodes periodically sleep. Neighboring nodes form virtual clusters to
auto-synchronize on sleep schedules. Inspired by PAMAS, S-MAC also sets the
radio to sleep during transmissions of other nodes. Unlike PAMAS, it only
uses in-channel signaling. Finally, S-MAC applies message passing
to reduce contention latency for sensor-network applications that require
store-and-forward processing as data move through the network. We evaluate
our implementation of S-MAC over a sample sensor node, the Mote, developed
at University of California, Berkeley. The experiment results show that,
on a source node, an 802.11-like MAC consumes 2--6 times more energy than
S-MAC for traffic load with messages sent every 1--10s.
Update 2012: page is superceeded, see I-LENSE for current information about S-MAC and more recent protocols.
People
Publications
- An Energy-Efficient
MAC Protocol for Wireless Sensor Networks (ps)
(also in pdf
)
Wei Ye, John Heidemann and Deborah Estrin
In Proceedings of the 21st International Annual Joint Conference of the IEEE
Computer and Communications Societies (INFOCOM 2002), New York, NY, USA,
June, 2002.
An earlier version is also available as a
Technical Report (ps)
(pdf
), ISI-TR-543, USC/ISI, Sept, 2001.
Update 2012: page is superceeded, see the I-LENSE publications for current information about S-MAC and more recent protocols like SCP-MAC.
Presentations
Software
We have implemented S-MAC on the
Mica Motes
running TinyOS
. However, our implementation is not based on the standard radio communication
stack in the TinyOS release. Instead, we have developed
a new communication stack
that provides more features to allow protocols at different layers can be
easily built.
The source code is now released and availble for
download at here
.
Last updated on Oct. 2, 2002 by
Wei Ye
.