1. By :
Prajwal Panchmahalkar
Nishant Reddy Kommidi
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2.  Introduction
 Problems
 Related Research
◦ LEACH
◦ POACH
◦ SAFE
◦ TTDD
◦ SPIN
 SPMS (Shortest Path Minded SPIN)
◦ Design
◦ Failure free case ( Example and Design)
◦ Evaluation
 Delay Analysis
 Energy Analysis
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3.  Sensor Networks, a particular class of wireless ad-
hoc networks in which the nodes have sensors
 Sensor nodes gather and disseminate data about
the physical conditions.
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4.  Sensor nodes are battery powered and usually
run out of battery
◦ Reducing energy consumption is an important
design consideration
 Node failures is evident – due to battery drain
or due to physical condition of their
deployment environment
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5.  Low Energy Adaptive Clustering Hierarchy
 Communicates directly with the respective cluster
head and cluster heads communicate with base
station.
 Does not consider end-to-end latency
 Assumes that base station is within communicating distance
of all nodes.
 Economic feasibility and the scalability of solutions.
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6.  Power Aware Caching Heuristics
 Determine the servers in the sensor network
at which the data should be cached.
 Aimed at minimizing the cost of data
dissemination from the sink node.
 What if the data cache fails?
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7.  Motivated by two problems
◦ Implosion – broadcast
◦ Overlap – redundant data
 Use high level descriptors – metadata
 Nodes exchange metadata prior to data
exchange
 What about the cost of dissemination ?
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8.  SPIN didn’t consider node failure in the
network.
 Adjust of power level with respect to distance
to the neighbor
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9.  Energy spent in wireless network is directory proportional to
dα
 d – distance between source and destination
 α – constant between 2 and 4
 SPMS uses multi-hop model for data transmission among nodes with
variable transmission power levels
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10.  Consider the following multihop routing
between A to C
Zone of A
B
1 1
A C
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Destination via COST
C - 5
C B 2
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11.  Knowing the route to destination
 Dealing with failures of intermediate nodes
?
?
?
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12.  Node neighbor zones are considers
◦ A region that the node can reach by transmitting at
maximum power level.
 Each node has a routing table for each of its
zone neighbors
◦ Distributed Bellman Ford algorithm is used
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13.  Motivated by SPIN
1. Meta-data exchange within zone neighbors
2. The node sends REQ packet to the source using the
shortest path.
3. If the source is not the next 1 hop neighbor the REQ is sent
through multiple hops
4. Relaying between nodes is used and meanwhile the
destination nodes wait for the ADV from the 1 hop
neighbors before sending the REQ
5. Energy is saved here compared to the transmission directly
to source node
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14.  If the destination node doesn’t receive ADV from the relay
node before the timer the timer expires it sends REQ to the
source through the shortest path
 A timer Tadv is used to wait for ADV
 Expended Energy in SPIN = 2nEr
 Expended Energy in SPIN = 2kEr (k- relay nodes)
 Ratio of Reception leads to n>k
 Another timer TDAT is used to wait for DATA
 REQ is resent if the timer expires before reception of the
data.
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15. adv
B
adv
A C
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16. REQ
B
A C
Waits Tadv to receive ADV from B
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17. DATA
B
A C
Waits Tadv to receive ADV from B
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18. ADV
B
A C
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19. REQ
B
A C
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20. DATA
B
A C
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21.  At each stage, the destination node maintains
a Primary Originator Node (PRONE) and
Secondary Originator Node (SCONE).
 PRONE is the primary choice for the REQ , if
PRONE fails SCONE is considered.
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22. REQ
B
C
A
D
Destination
Source
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23. B
REQ
A
D
Destination
Source
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24.  SPMS is cost and energy effective compared
to SPSM
 It reduces end-to-end data latency
 SPMS shortest distance multi-hop routing for
the data transfers which allows energy
savings.
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