kais t using mobile relays to prolong the lifetime of wireless sensor networks wei wang, vikram...

KAIST

Using Mobile Relays to Using Mobile Relays to Prolong the Lifetime of Prolong the Lifetime of

Wireless Sensor NetworksWireless Sensor Networks

Wei Wang, Vikram Srinivasan, Kee-Chaing ChuaMobiCom ‘05

Presentation by

Mrinalini SawhneyNetwork & Security Lab

(Dept of Computer Science, KAIST)

22 Using mobile relays to prolong the lifetime of WSNs

ContentsContents

Introduction & Motivation Use of mobile nodes as relays or sinks

Related worksEnergy conservation methods with mobile relay

Static routingDynamic routingNetwork lifetime comparisonLifetime upper bounds using Mobile relay

Proposed algorithmsAggregation Routing Algorithm (ARA)Aggregation Routing Algorithm with Limited Nodes (ARALAN)

Performance EvaluationsConclusions


Introduction [1/4]Introduction [1/4]

[1] – Yang et al, How to prolong the lifetime of Wireless Sensor Network.

Investigate the benefits of a heterogeneous Investigate the benefits of a heterogeneous architecture for WSN composed ofarchitecture for WSN composed of a few a few resource rich mobile nodes resource rich mobile nodes

and a large number of and a large number of simple static nodessimple static nodes

Mobile Relays or Mobile Sinks


Motivation [1/2]Motivation [1/2]

Scenario 2 -> very economical What about performance improvement from mobile node and the tradeoffs associated ??

Scenario 1Deploy a million static nodes 15 cents per nodeTotal deployment cost = $150,000

Scenario 2Few expensive resource rich mobile nodes and many simple static nodes10 nodes @ $100 each100,000 static nodes @ 15 cents/nodeTotal deployment cost = $16,000

VS


Introduction [3/4]Introduction [3/4]Sample network

Two components are connected via sensor nodes A & BLifetime of these two nodes is TBoth A & B are the critical bottleneck nodes in the network

Use of a mobile node doubles network lifetime

Shuttles between node A & BInherits the responsibility of the node with which its co-located


Introduction [4/4]Introduction [4/4]

Mobile Node could be eitherMobile relay or,Mobile Sink

Analyze the lifetime for 3 different cases using different routing algorithms

When the network is all staticWhen there is one mobile sinkWhen there is one mobile relay


Related WorksRelated WorksShah et al., “Data Mules: Modeling a three-tier architecture for sparse sensor networks”, in proceedings of the IEEE Wkshp, on Sensor network Protocols and Applications (SNPA) 2003Charkabarti et al., “Using Predictable Observer Mobility for Power Efficient Design of Sensor Network” The 2nd Int’l Wkshp on Information Processing in Sensor Networks (IPSN), 2003

Gandham et al., “Energy Efficient schemes for wireless sensor networks with multiple mobile base stations” in proceedings of IEEE GLOBECOM, DEC 2003Shankar et al., “Maximum lifetime routing in in wireless ad-hoc networks,”, in proceedings of 23rd IEEE INFOCOM, Mar 2004

…..

DisadvantagesMobile sink needs to roam around the networkAll nodes in the network need to be aware of the current location of the mobile sink


Energy Conservation Methods with Mobile Energy Conservation Methods with Mobile RelaysRelays

Static RoutingSensors know the location of mobile relays and redirect their packets through them

Lifetime extended by ui time unitsSort the original lifetime of static nodes in increasing order

{(l1,u1), (l2,u2), …., (ln,un)}

Stays in a sleep mode for duration ui


Energy Conservation Methods with Mobile Energy Conservation Methods with Mobile RelaysRelays

Dynamic RoutingRoutes to the sink depend upon the position of the mobile relayFocus of this paper

SS


Lifetime Improvement by using a Mobile Lifetime Improvement by using a Mobile RelayRelay


Lifetime Upper BoundsLifetime Upper BoundsWithout mobile relay, the lifetime upper bound is in the network

With one mobile relay, the lifetime upper bound is

With m mobile relays, the lifetime upper bound is

A mobile relay needs to stay only within a two hop radius of the sink in order to maximize the lifetime


Aggregation Routing Algorithm (ARA) Aggregation Routing Algorithm (ARA) [1/2][1/2]

Routing Algorithm

-> set of all nodes which can reach the sink with 2 hops -> set of all nodes outside the range Q2

O M


Aggregation Routing Algorithm (ARA) Aggregation Routing Algorithm (ARA) [2/2][2/2]

The # of nodes in a3 is always greater than the sum of that in area a1 and a2

There are 4ρ candidates for aggregate node


Another Proposed AlgorithmAnother Proposed AlgorithmMerits of ARA

Efficient upper bound of

Drawbacks of ARA algorithmEvery node needs to know the position of the mobile This is a huge overhead

Aggregation Routing Algorithm with Limited Nodes (ARALAN)Only a limited number of nodes in the network need to know the location of the mobile relayThe upper bound is maintained


Aggregation Routing Algorithm with Limited Aggregation Routing Algorithm with Limited Nodes (ARALAN)Nodes (ARALAN)

Use of shortest path routingOnce the information reaches Ps

Relay it to the aggregation ring – Rings,r

Information reaches aggregation ringsTravels through a series of aggregation rings before it reaches the aggregation nodeWhen the traffic reaches OM, its routed hop by hop


PerformancePerformancePerformance of Mobile Sink Approach

Lifetime would be atleast O(R) times better than static approach

Mobile relay ApproachNeed to use O(R) nodes to achieve the same performance


Performance EvaluationsPerformance EvaluationsWith one mobile relay

ScenarioRadius = 4 density = 4

# of nodes = 200

130% improvement


Performance EvaluationsPerformance Evaluations


ConclusionsConclusionsInvestigates the possibility of

Using the mobile node as a relayUsing the mobile node as a sink

Mobile sink always beneficial but application scenario is not feasible

With one mobile relay lifetime improvement of up to four times over the static approach

One static rich resource can improve the lifetime by 60%

One mobile relay can increase by almost 300%

kais t using mobile relays to prolong the lifetime of wireless sensor networks wei wang, vikram...

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