!!"10/14/03 EECS 228A S. Parekh & P. Varaiya # $ %$& & '( ) (( ( * +( ++'( $&' 10/14/03 EECS 228A S. Parekh & P. Varaiya, - & .%/ '$0 1 /& 2/& $/.% 3 #0 &#& %4%$!/ 555$'' ,&#'3 ' $6 .7 /6 # 8/7 & 3 /9 '.% : &'4 &#&!!/3 ' $6 #;% + $'' # .%/' 3 / $: /(&. $6 !!"/-* ' & '' ' '& $# 10/14/03 EECS 228A S. Parekh & P. Varaiya IntroductionEnabling technologies for deployment of low-power and low-cost sensor nodesAdvances in wireless communicationsAdvances in ElectronicsApplicationsHealthMilitaryHomeCommercial…Poised for tremendous impactBrings together challenges of many fields like electronics, communication, software, business opportunities10/14/03 EECS 228A S. Parekh & P. VaraiyaIntroduction – Main TasksKey tasks performed by Sensor Nodes:SensingData ProcessingCommunicationNetworking is a distinguishing feature10/14/03 EECS 228A S. Parekh & P. VaraiyaIntroduction –Distinguishing Features Differences between Sensor Networks and traditional Mobile Ad Hoc Networks (MANETs) Much lager number of nodes Dense deployment Limited in power Manly use broadcast paradigm Higher failure rate No global identifiers10/14/03 EECS 228A S. Parekh & P. VaraiyaIntroduction - ArchitectureSensor Network architecture10/14/03 EECS 228A S. Parekh & P. VaraiyaIntroduction – Design Issues Key design issues Fault tolerance Scalability Production cost Hardware constraints Network topology Environment Power consumption10/14/03 EECS 228A S. Parekh & P. VaraiyaIntroduction: Protocol StackProtocol stack for Sink and Sensor NodesPower management impactLocation impact10/14/03 EECS 228A S. Parekh & P. VaraiyaPhysical Layer 915 MHz ISM is widely used Long distance wireless is expensive Power needed behaves like dn, where d is distance and 2 n < 4 and n is closer to 4 for near-ground channels Multihop networks can overcome shadowing and path loss effects Binary modulation is more power efficient10/14/03 EECS 228A S. Parekh & P. VaraiyaData Link LayerExisting MAC protocols (why they can’t be used)Central controlling agentQoS and BW efficiency very importantPower efficiency of secondary importanceBluetooth and MANET closest cousins, still key differencesDense deploymentPower conservation criticalNode failures10/14/03 EECS 228A S. Parekh & P. VaraiyaData Link Layer: MACMAC for Sensor NetworksSelf-Organizing Medium Access Control for Sensor Networks (SMACS) and Eavesdrop-and Register (EAR) AlgorithmCSMA-based Medium AccessHybrid TDMA/FDMA-based10/14/03 EECS 228A S. Parekh & P. VaraiyaData Link Layer:MAC Considerations Key design consideration for MAC Power saving modes of operationAvoid turning on and off based on component characteristics Error controlFEC is preferred over ARQ10/14/03 EECS 228A S. Parekh & P. Varaiya Network Layer Driving factors for design of Network Layer Power efficiency Data aggregation Attribute-based addressing and location awareness10/14/03 EECS 228A S. Parekh & P. VaraiyaNetwork Layer:Energy Efficient RoutingEnergy efficient routingMaximum PA route: Sink-E-F-TMinimum energy route: Sink-A-B-TMinimum hop route: Sink-D-TMaximum minimum PA node route: Sink-D-T10/14/03 EECS 228A S. Parekh & P. VaraiyaNetwork Layer: Proposed Schemes Routing schemes Small Minimum Energy Communication Network (SMECN)Create energy-efficient subgraph FloodingDeficiencies include implosion, overlap, resources blindness GossipingBroadcast to randomly selected neighborLong propagation time10/14/03 EECS 228A S. Parekh & P. VaraiyaNetwork Layer:Proposed Schemes - 2Routing schemesSensor Protocol for Information via Negotiation (SPIN)Low-energy Adaptive Clustering HierarchySetup phase: Periodically select new clusterheadSteady state phase10/14/03 EECS 228A S. Parekh & P. VaraiyaNetwork Layer:Proposed Schemes - 3Routing schemesDirected DiffusionSink sends interestNodes store interest entrySource setup gradient from source to sinkRumor routing optimizes the interest indication phase10/14/03 EECS 228A S. Parekh & P. VaraiyaNetwork Layer:Proposed Schemes - 410/14/03 EECS 228A S. Parekh & P. VaraiyaTransport and Application LayersNot much work on these layersUDP/TCP splitting along sensor node – sink –user is proposedLimited power and memory consideration for transport layer designApplication layer ideas:Sensor Management ProtocolTask Assignment and Data Advertisement ProtocolSensor Query and Data Dissemination Protocol10/14/03 EECS 228A S. Parekh & P. VaraiyaOngoing Research
View Full Document
Unlocking...