1

Multipath Routing in WSN with multiple Sink nodes

YUEQUAN CHEN, Edward Chan and Song Han

Department of Computer Science

City University of HongKong

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Outline

• Issues of energy consumption in WSN

• Architecture of Multiple Sink

• Main Idea in MRMS

• MRMS protocol description

• Experimental Results

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Issue in Energy Consumption of WSN

• Sensors near the sink nodes will dissipate energy faster than other sensors

• How to scale the network size

Solution: Deploying multiple Sink nodes in WSN is one of best choice.

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Architecture of Multiple Sink Nodes

S

S

S

j

i

Sensor node

S Sink node

d

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Main Idea in MRMS

• Topology Discovery– Three-color algorithm

– Based on path cost

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Main Idea in MRMS (cont)

• Cluster Maintenance– Energy monitoring

– Cluster reconstruction

• Path Switching– Patch Switching based on path cost

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MRMS protocol description－ Topology Discovery

Before Topology Discovery

After Topology Discovery

S

S

S

sensor node

S Sink node

S

S

S

undiscovered sensor

S Sink node

cluster head

onecluster

cluster children

multi-hoppath

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Topology Discovery

• Topology Discovery is based on three-color algorithm

• The cluster is stateless

• The metric of constructing the cluster is based on path_cost using Dijstra algorithm

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MRMS protocol description － Intra-Cluster Reconstruction

0.12

0.23

0.19

0.32

0.08

RE RE: residual energy

Old CH

BroadcastSELECT NEW CH

0.12

0.23

0.19

0.32

0.08

RE RE: residual energy

Old CH

Maximum ResidualEnergy node

(a) Broadcast SELECT_NEW_CH

(b) Select Maximum Residual Energy node

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MRMS protocol description－ Intra-Cluster Reconstruction

(c) Broadcast NEW_CH (d) New Cluster after re-construction

0.03

0.12

0.23

0.19

0.32

0.08

RERE: residual

energy

Old CH

BroadcastNEW CH

Maximum ResidualEnergy node

0.03

0.12

0.23

0.19

0.32

0.08

RE RE: residualenergy

New CH

Point to NewCH

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MRMS protocol description－ Inter-Cluster Reconstruction

(a) Before change delivery node

(b) After change delivery node

S0.012

0.002

0.003 CH

Old deliverynode

0.010

0.004

0.011One hop

cost

Path_cost Multi-hopspath

S0.012

0.002

0.003 CH

New deliverynode

0.010

0.004

0.011One hop

cost

Path_cost Multi-hopspath

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Cluster Reconstruction

• Cluster Header monitors its energy periodically

• In the intra-cluster reconstructing, select the max residual energy as new cluster head

• In the inter-cluster reconstructing, select the node whose path_cost to sink is min as new delivery node.

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MRMS protocol description－ Path Switching

(a) Before path switching (b) After path switching

S3 S1

AC

0.52

0.08

cost primarypath

Deliver Node ofprimary path

CH

S2

B

0.32 0.40

0.10 0.12

costAlternative

pathpath_cost Multi-hops

path

S3 S1

AC

0.52

0.08

cost primarypath

Deliver Node ofprimary path

CH

S2

B

0.32 0.40

0.10 0.12

costAlternative

pathpath_cost Multi-hops

path

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Path Switching

• Using event-based approach to trigger the path switching, not periodical update approach

• Select the min path_cost to other sink node as new path.

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Experimental Results

Time to First Node Failure

0

200

400

600

800

1000

1200

Ti me (s)

Di rectFl oodi ngTopDi scAl gori thmVoronoiAl gori thmMRMS

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Experimental Results

Number of Dead Nodes

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Experimental Results

Average Energy Consumption for packet

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Experimental Results

Average Hop Count vs Time

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Experimental Results

Average Distance to Sink vs Time

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Experimental Results

Packet Delivery Ratio

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Contributions

• New path cost metric

• Stateless clusters

• Path switching

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Thanks

Any Questions?