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Introduction There is a multiplicity of scenarios in sensor networks –Environmental control in office building –Monitoring of seismic activity –Smart home providing security –Interactive museum
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Data funneling : routing with Data funneling : routing with aggregation and compression for aggregation and compression for
wireless sensor networkswireless sensor networks
Petrovic, D.; Shah, R.C.; Ramchandran, K.; Rabaey, Petrovic, D.; Shah, R.C.; Ramchandran, K.; Rabaey, J. ;J. ;
SNPA 2003SNPA 2003
OutlineOutline• Introduction• Data funneling • Simulation result• Coding by ordering• Conclusion
IntroductionIntroduction• There is a multiplicity of scenarios in
sensor networks– Environmental control in office building– Monitoring of seismic activity– Smart home providing security– Interactive museum
IntroductionIntroduction• Energy consumption determines the
life time of a sensor network• Communication wirelessly consumes
more power at the nodes than other activity
• We want to minimize the amount of communication required by the sensor nodes
IntroductionIntroduction
• Two methods are discussed to improve the lifetime– Packet aggregation technique– Data compression
Data funnelingData funneling• The network environment
– Sensors• Numerous• Sense physical phenomena• Generate readings
– Controllers• Fewer in number• Observe the readings from multiple sensors
Data funnelingData funneling• Sensors may
– Report to the controller at approximately the same time
– Have similar headers• Savings may be realized by
combining different packets into one large packet with a single header
Data funnelingData funneling• It reduces the overhead of packet
headers• Decreases the probability of packet
collision – It allows the same amount of
information to be transmitted by fewer nodes
Data funnelingData funneling
Data funnelingData funneling
Data funnelingData funneling
Data funnelingData funneling
Data funnelingData funneling• Data funneling creates clusters
within the sensor network– The clusters it creates have a dynamic
hierarchy– There is not a single cluster head
• Border nodes take turns acting as cluster head
• Spreading out the responsibility and the load
Simulation resultSimulation result• OpNet network simulator• Each sensor sends it reading to the
controller every 10 seconds• If the average number of sensor
readings per packet is 7– The energy expected on packet header
is reduced by 6/7=86%
Simulation resultSimulation result• α is the ratio of bits in a packet
header to the total number of bits in a packet
• m is the average number of sensor readings per transmitted packet
• Total energy reduced by– α*((m-1)/m)*100%
Simulation resultSimulation result
Coding by orderingCoding by ordering• The border node receives the
packets from n sensors and make up a super-packet
• Super-packet– Contain each node’s
• ID • Payload
Coding by orderingCoding by ordering• The border node has the freedom to
choose the ordering of the packets within the super-packet
• The border node is allowed to choose to suppress some of the packets– Not to include them in the super-packet
Coding by orderingCoding by ordering• For example
– Four node with ID 1,2,3,and 4– Each generates an independent reading
which is a value from the set {0,…,5}– The border node can choose
• To suppress the packet from node 4• An appropriate ordering among the 3!=6
– Possible orderings of the packets from nodes 1,2,3 indicate the value generated by node 4
Coding by orderingCoding by ordering
Coding by orderingCoding by ordering• n : the number of packets present at
the encoder• k : the range of possible values
generated by each sensor(2k)• d : the range of node ID’s of the
sensor nodes• l : the largest number of packet that
can be suppressed
Coding by ordering-Coding by ordering- achievable achievable with simple codecwith simple codec
To alleviate this problem , Stiring’s approximation is used to convert (1)
ConclusionConclusion• This work proposes a routing
algorithm-Data Funneling• It can reduce the amount of energy
spent on communication • It also reduces the probability of
packet collision