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Energy Aware Networks
By Kevin Burnette
Energy Aware Networks
• What are energy aware networks?
• Why do we need energy awareness?
• How is energy awareness achieved?
What Are Energy Aware Networks
• An energy aware network is a system that
has energy awareness built in to every
stage of its design so that it can make
dynamic tradeoffs between system
performance and over all system life.
What do we need it for?
• Sensor nodes run off of a battery so they
must operate on a very small power
reserve.
• Since batteries are not replaceable the
nodes lifetime must be lengthened using
energy aware techniques.
• Energy consumption directly affects node
lifetime and also the system lifetime.
How do they do it?
• Architecture (Hardware)
• Algorithmic (Software)
• Co-Design (Hardware and Software)
Typical sensor node design
Hardware
• MCU - micro control unit, is the processor
of the node
• Radio – used in wireless communication
between nodes
• Sensors – used in event tracking in
environments
• Battery – powers the node
• DC-DC – provides constant voltage to
node
Hardware - Life Issues
• Power consumption of different operating
modes (Idle, Active, Sleep), transition cost,
and time spent in each mode will be the
largest factors on node life dealing with the
MCU.
• Modulation technique, data rate, transmit
power (determined by distance to
receiver), and operational duty cycle are
the largest life reducing factors from the
radio.
Hardware - More Life Issues
• Sensors vary widely and their power
consumptions do as well, however in
some nodes it can be very high.
• Exceeding the rated current draw from the
battery for long periods can result in
shorter battery life
• The efficiency factor of the DC-DC unit is a
major factor in determining the life of the
node
The life of a node if very dependent on the
power consumptions of its components. To
maximize life span tradeoffs on performance
must be made to cut power consumption.
Software
• System lifetime can be
increased if the OS,
application layer, and network
protocols are all designed to
be energy aware.
• The OS plays a major role in
coordinating energy
awareness between the other
components
• Energy awareness must also
be designed into every layer of
network protocols.
Communication schemes
• Communication can
be very taxing on
power resources.
• Energy aware packet
forwarding,
modulation schemes
and link layer
optimizations are
implemented to
reduce this problem.
Protocols
•
•
•
•
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PAMAS
WiseMAC
MREP and variations
Flow augmentation
Flow redirection
Co-Design
• The best way to implement is by codesigning your hardware and software
with energy awareness as the main goal.
• Global decisions must be made energy
aware such as traffic distribution, topology
management.