mobile adhocnet overview suresh
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Ad Hoc Networks: Ad Hoc Networks: OverviewOverview
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Textbook
C. Siva Ram Murthy and B. S. Manoj, Ad Hoc Wireless Networks: Architectures and Protocols, Prentice Hall PTR, 2004.
Charles E. Perkins, Ad hoc Networking, Addison –
Wesley, 2000
REFERENCESREFERENCES
1. Stefano Basagni, Marco Conti, Silvia Giordano and Ivan stojmenovic, Mobilead hoc networking, Wiley-IEEE press, 2004.
2. Mohammad Ilyas, The handbook of adhoc wireless networks, CRC press, 2002.
3. T. Camp, J. Boleng, and V. Davies “A Survey of Mobility Models for Ad Hoc Network Research,” Wireless Commun. and Mobile Comp., Special Issue on Mobile Ad Hoc Networking Research, Trends and Applications, vol. 2, no. 5, 2002, pp. 483–502.
4. A survey of integrating IP mobility protocols and Mobile Ad hoc networks, Fekri M. Abduljalil and Shrikant K. Bodhe, IEEE communication Survey and tutorials, v no.1 2007
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REFERENCESREFERENCES
5. V.T. Raisinhani and S.Iyer “Cross layer design optimization in wireless protocol stacks”Comp. communication, vol 27 no. 8, 2004.
6. V.T.Raisinhani and S.Iyer,”ÉCLAIR; An Efficient Cross-Layer Architecture for wireless protocol stacks”,World Wireless cong., San francisco,CA,May 2004.
7. V.Kawadia and P.P.Kumar,”A cautionary perspective on Cross-Layer design,”IEEE Wireless commn., vol 12, no 1,2005.
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Related SitesRelated Sites
Advanced Network Technologies Division, NIST, Wireless Ad Hoc Networks,
http://w3.antd.nist.gov/wahn_home.shtml Autonomous Networks Research Group, USC
WSN bibliography, http://ceng.usc.edu/~anrg/SensorNetBib.html
IETF MANET WGhttp://www.ietf.org/html.charters/manet-charter.html
IEEE 802 WGhttp://grouper.ieee.org/groups/802/dots.html
Zigbeehttp://www.zigbee.org
TinyOShttp://www.tinyos.net/
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Wireless Network TechnologyWireless Network Technology
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Internet
WLAN
Cellular
[Mobile/Wireless] Ad Hoc Networks
Wireless NetworksWireless Networks
Wireless Networks Infrastructured Network
• Cellular Network (3GPP or 3GPP2)• Wireless LAN (IEEE 802.11)
Infrastructureless Network• Ad Hoc Network
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Ad Hoc Networks vs. …Ad Hoc Networks vs. …
Ad hoc networks vs. Wireless mobile networksInfrastructureless vs. Infrastructured NetworkAll devices of an ad hoc network are likely to have
similar constraints Ad hoc networks vs. Peer-to-peer networks
P2P devices use existing networked structures such as Internet
All P2P networks are not ad hoc network • Because NOT all ad hoc network utilize an existing
structure for the communication among devices
Ad hoc computing vs. Pervasive computingThe devices for pervasive computing are usually very
small and can be embedded in any type of objects• Users are sometimes not even aware of the existence of
the embedded electronic chips
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Ad hoc networks (1)Ad hoc networks (1) Temporary network composed of mobile
nodes without preexisting communication infrastructure, such as Access Point (AP) and Base Station (BS).Each node plays the role of router for multi-hop routing.
Self-organizing network without infrastructure networksStarted from DARPA PRNet in 1970
Cooperative nodes (wireless)Each node decode-and-forward packets for other nodes
Multi-hop packet forwarding through wireless linksProactive/reactive/hybrid routing protocols
Most works based on CSMA/CA to solve the interference problem IEEE 802.11 MAC
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Ad hoc networks (2)Ad hoc networks (2)
But, there is no links Nodes simply radiate energy
Nodes can be cooperative in many other ways (complex) Amplify and forward interference cancellation to increase SNR
There may be many things out there that we can take advantage of across layers for improvement!
F
D
E
C
A
B
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Ad Hoc Network (3)Ad Hoc Network (3)
Ad hoc networks
Mobile ad hoc networks(MANETs)
Wirelss Mesh Networks(WMN)
Wireless sensor networks
The application areas, the security requirements and the constraints of the single devices differ …
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Cellular Net vs. Ad Hoc Net (1)Cellular Net vs. Ad Hoc Net (1)
Cellular Net Ad Hoc Net
Fixed infrastructure-based Infrastruxture-less
1-hop wireless links Multi-hop wireless links
Guaranteed bandwidth Shared radio channel
Centralized routing Distributed routing
Seamless connectivity (low call drops during hand offs)
Frequent path breaks due to mobility
High cost and time of deployment
Quick and cost-effective deployment
Frequency reuse through geographical channel reuse
Dynamic frequency reuse based on CSMA
Time sync: easier to achieve. Difficult and consume BW
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Cellular Net vs. Ad Hoc Net (2)Cellular Net vs. Ad Hoc Net (2)
Cellular Net Ad Hoc Net
BW reservation: easierBW reservation requires complex MAC
App. Domain: civilian and commercial sector
Battlefields, emergency & rescue operations, collaborative computing
High cost of net maintenanceSelf-organization and maintenance is built into network
MHs: low complexityMobile hosts require more intelligence (routing, switching capability)
Major goal of routing: max call acceptance, min call drop
Aim of routing is to find paths with min overhead and quick reconfiguration of broken paths
Widely deployed
Several issues are to be addressed for commercial deployment,Widespread use in defense
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Major ApplicationsMajor Applications
MilitaryEmergency ServiceCollaborative and Distributed
Computing Wireless Mesh NetworkWireless Sensor NetworkTelematicsWireless Personal Area NetworkHome NetworkAd Hoc Relay for Cellular NetworkNetworks for ubiquitous computing
Demands for group
communications
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MilitaryMilitary
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Emergency Service Emergency Service
MANET Application III:MANET Application III:OthersOthers
Search & Rescue / Emergency Services
MANET Application I: MANET Application I: Vehicular Ad-hoc NETwork (VANET)Vehicular Ad-hoc NETwork (VANET)
Integrated traffic simulator with network simulator
Vehicle mobility-based routing strategy
Make use of public transport (e.g. trams, trains, buses) or traffic facilities (traffic light, lamp post) as data carrier or relay in MANET
E.g. A biker-NET in the Blackforest
MANET Application II: MANET Application II: Robot (-assisted) Ad hoc Network Robot (-assisted) Ad hoc Network
Mobile robots moving around wireless sensor network
– to collect/send data from/to sensors
– to aid in localization
Mobile robots serve as relay in MANET
– How to guarantee connectivity?
– How to conserve energy?
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MANET – Research TargetMANET – Research Target
MANETNo infrastructureSelf organizing
networksCommunications via
mobile nodesDynamic topologyHeterogeneity
bandwidth-constrained variable-capacity links
Limited physical security
Nodes with limited battery life and storage capabilities
Issues in MANETAd Hoc Unicast RoutingAd Hoc
Multicast/Broadcast Routing
Power SavingGlobal Connectivity for
MANETAddressing & DNS
ServiceAutomatic Support of
Networking in MANET• MANET
Autoconfiguration
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Wireless Mesh NetworksWireless Mesh Networks
Mesh network implemented over WLAN
Industrial standards ActivitiesIEEE 802.11, IEEE 802.15, IEEE 801.16 have
established sub-working groups to focus on new standards for WMNs
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WMN ArchitectureWMN Architecture
WMNs (Wireless Mesh Networks) consist of: mesh routers and mesh clients
Mesh routersConventional wireless AP (Access Point) functionsAdditional mesh routing functions to support multi-hop
communicationsUsually multiple wireless interfaces built on either the
same or different radio technologies Mesh clients
Can also work as a router for client WMN Usually one wireless interface
Classification of WMN architecture Infrastructure/Backbone WMNsClient WMNsHybrid WMNs
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Infrastructure/backbone Infrastructure/backbone WMNsWMNs
Internet
Wi-FiNetworks
CellularNetworks WiMAX
Networks
SensorNetworksBase Station
Sink nodeSensor
Wireless MeshBackbone
Wired ClientsMesh RouterMesh Router
with GatewayMesh Routerwith Gateway
Mesh Routerwith Gateway/Bridge
Mesh Routerwith Gateway/Bridge
Mesh Routerwith Gateway/Bridge
Access Point
Base Station
Mesh Routerwith Gateway/Bridge
Wireless Clients
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Client WMNsClient WMNs
Mesh Client
Mesh Client
Mesh Client
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Hybrid WMNsHybrid WMNs
Wi-Fi, Wi-MAX,Sensor Networks,
Cellular Networks, etc.
Internet
Wireless Mesh Clients
Wireless MeshBackbone
Conventional Clients
Mesh Router
Mesh Router
Mesh Routerwith Gateway
Mesh Routerwith Gateway
Mesh Routerwith Gateway/Bridge
Mesh Router Mesh Router
Mesh Routerwith Gateway/Bridge
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Sensor Network ModelSensor Network Model
Source
Stimulus
Sink
Sink
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Wireless Sensor NetworksWireless Sensor Networks
A sort of ad-hoc networks A network of low cost,
densely deployed,untethered sensor nodes
Application areas:heath, military, and home
Placed in inaccessible terrains or disaster areas It may be impossible to recharge batteries
Different Node Characteristics from Traditional nodes # of nodes in a sensor network can be several orders of
magnitude higher than the nodes in an Ad Hoc network (100s to 1000s nodes)
Densely deployed (20 nodes/m3) Prone to failures Topology changes very frequently Mainly use a broadcast communication, whereas most Ad Hoc
networks are based on point-to-point Limited in power, computing capacities, and memory May not have global ID because of the large amount of
overhead and large number of sensors
Ad Hoc NetAd Hoc Net
Wireless Wireless Sensor Sensor NetworkNetwork
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Existing Wireless Net vs. Sensor Existing Wireless Net vs. Sensor NetNetCellular system Bluetooth,
MANETSensor Network
Single Hop Multi-hop Multi-hop
High QOSBandwidth efficiency
High QOS Power conservation
Limited bandwidthLarge number of nodeNarrow radio range
Frequent topology change
Station to Base station
Peer to peerPeer to multi node
Peer to multi node
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Sensor Networks ArchitectureSensor Networks Architecture
Sensor nodeMade up of four basic components
• Sensing unit, Processing unit, Transceiver unit, and Power unit
Additional application-dependent components• Location finding system, power generator, and
mobilizer
Scattered in a sensor fieldCollect data and route data back to the sink
SinkCommunicate with the task manager node
(user) via Internet or satellite
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Challenges in Ad Hoc NetworksChallenges in Ad Hoc Networks
Limited wireless transmission range Broadcast nature of the wireless
mediumPacket losses due to transmission errors Mobility-induced route changes Mobility-induced packet losses Battery constraints Potentially frequent network partitions Ease of snooping on wireless
transmissions (security hazard)
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Issues in Ad Hoc NetworksIssues in Ad Hoc Networks
Medium access schemeRoutingMulticastingTransport layer protocolPricing shcemeQoS provisioningSecurityEnergy managementAddressing and service discoveryScalabilityDeployment considerations
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Medium Access SchemeMedium Access Scheme Distributed operation Synchronization Hidden terminal problem Exposed terminal problem Throughput Access delay Fairness: especially for relaying nodes Real-time traffic support Resource reservation Ability to measure resource availability Capability for power control Adaptive rate control Use of directional antennas
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Routing (1)Routing (1)
ChallengesMobility
• results in path breaks, packet collisions, transient loops, stale routing information, and difficulty in resource reservation
BW constraintsError-prone and shred channel
• BER: 10-5 ~ 10-3 wireless vs. 10-12 ~ 10-9 wired
Location-dependent contention• Distribute load uniformly
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Routing (2)Routing (2)
RequirementsMinimum route acquisition delayQuick route reconfigurationLoop-free routingDistributed routing approachMinimum control overheadScalabilityQoS provisioningSupport for time-sensitive trafficSecurity and privacy
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MulticastingMulticasting
Robustenessrecover and reconfigure quickly from potential
mobility-induced link breaksEfficiencyMin control overheadQoS supportEfficient group managementScalabilitysecurity
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Transport Layer ProtocolsTransport Layer Protocols
UDPNo congestion control congestion increase
contention degrade throughput
TCP: major performance degradation due toFrequent path break
route reconfiguration RTO ReTx/CC low throughput
Stale routing information• Increase out-of-order packets dup ACKs CC
High channel error rate• Loss of data/ACK ACK is delayed RTO CC
Frequent network partition• All the packets dropped RTO/multiple ReTx increase
RTO/CC
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SecuritySecurity
DoS attackResource consumption
Energy depletionBuffer overflow
Host impersonationInformation disclosureInterference
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Energy ManagementEnergy Management
Tx power mgmtMAC: sleep modeRouting: consider battery life time: load
balancingTransport: reduce ReTxApp
Battery energy mgmtExtend battery life by taking adv of chemical
properties, discharge patterns, and by the selection of a battery from a set of batteries
Processor power mgmtDevice power mgmt
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Deployment Consideration (1)Deployment Consideration (1)
Adv. in ad hoc netLow cont of deploymentIncremental deplymentShort deplyment timeReconfigurablity
Scenario of deploymentMilitary deployment: data-centric or user-
centricEmergency operation deployment: hend-held,
voice/data, < 100 nodesCommercial wide-area deployment: e.g. WMNHome network deplyment
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Deployment Consideration (2)Deployment Consideration (2)
Required longevity of network Area of coverage Service availability: redundancy Operational integration with other
infrastructureSatellite network, UAV(unmanned aerial vehicles), GPSCellular network
Choice of protocolsTDMA or CSMA-based MAC?Geographical routing (using GPS)Power-saving routing ?TCP extension ?