Zone Sharing: A Hot-Spots Decomposition

Scheme for Data-Centric Storage in Sensor Networks

Mohamed Aly, Nicholas Morsillo, Panos K. Chrysanthis, and Kirk Pruhs

ACM International Workshop on Data Management for Sensor Networks(DMSN), August 29, 2005, Trondheim, Norway.

Outline

• Introduction

• Related Work

• Zone Sharing– Distributed Migration Criterion (DMC)– Single-Hop Zone Sharing (SHZS)– Multiple-Hop Zone sharing (MHZS)

• Simulation

• Conclusion

Introduction• Event

– One or more sensor compose– A set of attributes

• In order to improve the lifetime of nodes– Propose data centric storage

• Event to sensor mapping– Based on the attributes values of an event

Introduction

• The problem is the storage hot-spot– Due to irregular data distribution– A high percentage of load assigns to small

potion of the nodes

• Propose Zone Sharing (ZS)– Hot-spot– Energy saving– Network lifetime

Related Work– Multi-dimensional Range Queries in Sensor networks

1110

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[0, 0.25)

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[0, 0.5)

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0110

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[0.5

, 1)

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[0, 0

.5)

[0.25, 0.5) [0.5, 0.75) [0.75, 1)

[0.75, 1)[0.5, 0.75)

[0.25, 0.5)[0, 0.25)

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E1= <0.8, 0.7>

Store E1

ligh

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temperature

Related Work– Multi-dimensional Range Queries in Sensor networks

• Routing an event to its owner

• Compare event code with node own zone code

• Hand to GPSR

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E1= <0.8, 0.7>

Store E1

Related Work– Multi-dimensional Range Queries in Sensor networks

• Range queries• Query initially routed

– corresponding to the entire range

• Split a large query into smaller subqueries

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[0, 0.5)

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Q10= <.75-1, .5-.75>

Q1= <0.5-1, 0.5-1>

Q12= <.75-1, .75-1>Q11= <.5-.75, . 5-1>

Zone sharing –Basic Idea

Z = 0 Z = 11

Z = 10S1

S2

S3

70%

5%

25%

Z = 01 Z = 1

Z = 00

S1

S2

S3

35%

35% 30%

(migrator)

(donor)

(receiver)

Zone sharing –Distributed Migration Criterion (DMC)

• lmigrator : the original load of the migrator

• ldonor : the total load of the donor

• T : the mount of load that the donor passes to the migrator

Applied by the donor and the receiverApplied by the donor and the receiver

12

3

donor

70%

migrator

receiver

5%

25%

Applied by the migratorApplied by the migrator

C1 should be greater than or equal to 2 to make sure that the donor is really falling in a hot-spot

C2 should be greater than or equal to 2 to avoid cyclic migrations

1

2

3donor 35%

migrator

receiver

35%30%

Zone sharing –Distributed Migration Criterion (DMC)

Applied by the donorApplied by the donor Applied by the migratorApplied by the migrator Applied by the receiverApplied by the receiver

12

3

donor

migrator

receiver

E1 、 E2 and E3 must be less than or equal to 0.5

12

3

donor

migrator

receiver

12

3

donor

migrator

receiver

To make sure in the migration To make sure in the migration process will not cause the deathprocess will not cause the death

• Goal: Overall minimal changes to the original DIM

• Single Hop Zone Sharing:– A zone can be traded at most once– Periodic exchange of neighbors information– DMC applied locally by nodes– No changes needed to GPSR

• Applicability: Small Hot Spots

Zone sharing –Single-Hop Zone Sharing (SHZS)

Zone sharing –Single-Hop Zone Sharing (SHZS)

Z = 0 Z = 11

Z = 10S1

S2

S3

70%

5%

25%

Z = 01 Z = 1

Z = 00

S1

S2

S3

35%

35% 30%

Request to Migrate message

Inform migration decision

Accept to Migrate message

• Problems:– Large hot-spots: overloaded neighbors

• DMC hard to be satisfied

– Zone traded only once • nodes still in hot-spots after migration process

– Messages pass by donor before going to migrator • energy consumption overhead

• Solution:– Allow a zone to be traded more than once

Zone sharing –Single-Hop Zone Sharing (SHZS)

Zone sharing –Multiple-Hop Zone Sharing (MHZS)

Zone address Original donor Final migrator

110 6 4

A Shared Zones List (each node)

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hot-spots

migrator4

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1100

Zone sharing –Multiple-Hop Zone Sharing (MHZS)

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Multiple sharing of the same zoneMultiple sharing of the same zone

migrator

2

011

1100111000

Zone sharing –Multiple-Hop Zone Sharing (MHZS)

1

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0000 001 10

3 56

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4

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Multiple sharing of the same zoneMultiple sharing of the same zone

2

011

1100111000

Zone address Original donor Final migrator

110 6 2

A Shared Zones List (each node)

Simulation

Network of sizes ranging 50~300

Initial energy 50 units

Radio range 40m

Storage capacity 15 units

DMC parameter C1 C2 2

DMC parameter E1 E2 E3 0.3

Simulation—Data persistence

Networks with a 30% hot-spot

Simulation—Quality of Data Query size of a 50% query for networks with a 50% hot-spot

Simulation—Load balancing

Networks with a 40% hot-spot

Simulation—Energy consumption

Networks with a 50% hot-spot

Conclusion

• A novel scheme – Decomposing storage load of hot-spots– The hot-spots nodes toward their neighbor

• In the future– Incremental load balancing throughout the

network time