VICTOR MAESTRE RAMIREZ - Planetary Defender on NASA's Double Asteroid Redirec...
Energy conservation in wireless sensor networks
1. Energy Conservation in Wireless
Sensor Networks
Under supervision: Dr. Ahmed Akl
Presented by: Ahmed Reda Elshami
Course Code: CC735
1CC73510/7/2013
2. Overview
• Introduction
• Challenge
• Architecture of a typical WSN
• Power breakdown
• Basic Approaches
• Taxonomy approaches
• Future Work
• Questions
• Reference
2CC73510/7/2013
3. Introduction
• A wireless sensor network consists of sensor
nodes deployed over a geographical area for
monitoring physical phenomena like
temperature, humidity, vibrations and so on.
3CC73510/7/2013
4. Challenge
• Power, Power, Power, …
• Life time with two AA batteries ≈ 20 days
• Processing capacity evolution VS. Battery
capacity evolution
4CC73510/7/2013
5. Architecture of a typical wireless
sensor node
• sensor node is a tiny device that includes four
main components
MCU = Microcontroller Unit ADC = Analog Digital Converter
DC-DC = Direct current to Direct current converter
5CC73510/7/2013
6. Power breakdown
• The communication subsystem > computation
subsystem
• The radio energy consumption is of the same
order in the reception = transmission = and idle
states, while the power consumption drops of at
least one order of magnitude in the sleep state.
• Depending on the specific application, the
sensing subsystem might be another significant
source of energy consumption
6CC73510/7/2013
7. Basic Approaches to Energy
Conservation in WSNs
Basic Approaches
to Energy
Conservation in
WSNs
Duty cycling
Data-driven
approach
Mobility approach
7CC73510/7/2013
12. Future Work
• The integration of the different approaches
into a single off-the-shelf workable solution
• Many real applications have shown the power
consumption of the sensor is comparable to,
or even greater than, the power needed by
the radio.
12CC73510/7/2013
14. Reference
• Giuseppe Anastasi, Marco Conti, Mario Di
Francesco, Andrea Passarella, (2008), Energy
Conservation in Wireless Sensor Networks: a
Survey. Elsevier B.V
14CC73510/7/2013
sensor nodes are generally battery-powered devices
on-board processing
wireless communication
sensing capabilities
Reduce energy consumption of nodes, so that the network lifetime can be extended to reasonable times
external power supply sources often exhibit a non-continuous behavior so that an energy buffer is needed as well
Sensing - for data acquisition from the physical surrounding environment
Processing - for local data processing and storage
Communication - for data transmission
Power - supplies the energy needed by the device to perform the programmed task
location finding system to determine their position
a mobilizer to change their location or configuration (e.g., antenna’s orientation), and so on
external power supply sources often exhibit a non-continuous behavior so that an energy buffer is needed as well
duty cycle is defined as the fraction of time nodes are active during their lifetime
Duty cycling is mainly focused on the networking subsystem
the radio should be switched off as soon as there is no more data to send/receive
Topology Control - By node redundancy - select only a minimum subset of nodes to remain active for maintaining connectivity otherwise sleep mode
nodes selected by the topology control protocol do not need to maintain their radio continuously on. They can switch off the radio
increasing the network lifetime by a factor of 2-3 compare to all nodes always on
data acquisition schemes are mainly aimed at reducing the energy spent by the sensing subsystem.
Data reduction all these techniques aim at reducing the amount of data to be delivered to the sink node
In-network processing performing data aggregation(e.g., computing average of some values) at intermediate nodes between the sources and the sink. result, the amount of data is reduced while traversing the network towards the sink
Data compression – encoding @ sender & decoding information @ Slink
Data prediction – building model describing data evolution within certain error bounds & stored @ node and sink node
Mobile Node part of the network infrastructure = fully controlled
Mobile Node part of the environment = might be not controllable ex: if they follow strict schedule, then they have a
completely predictable mobility otherwise they will have random behavior
2- We assume the energy consumption of the radio is > energy consumption due to data sampling or data processing, however