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7/31/2019 01 AdHocNet Overview
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TextbookC. Siva Ram Murthy and B. S. Manoj, Ad Hoc Wireless
Networks: Architectures and Protocols, Prentice HallPTR, 2004.
ReferencesCarlos de Morais Cordeiro and Dharma Prakash
Agrawal, Ad Hoc & Sensor Networks: Theory andApplications, World Scientific Publishing Co., 2006.
Feng Zhao and Leonidas Guibas, Wireless Sensor
Networks: An Information Processing Approach,Elsevier, 2004.
Edgar H. Callaway, Jr., Wireless Sensor Netwoks:Architectures and Protocols, Auerbach, 2004.
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Related Sites
Advanced Network Technologies Division, NIST,Wireless Ad Hoc Networks,
http://w3.antd.nist.gov/wahn_home.shtml
Autonomous Networks Research Group, USCWSN 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/
http://w3.antd.nist.gov/wahn_home.shtmlhttp://ceng.usc.edu/~anrg/SensorNetBib.htmlhttp://www.ietf.org/html.charters/manet-charter.htmlhttp://grouper.ieee.org/groups/802/dots.htmlhttp://www.zigbee.org/http://www.tinyos.net/http://www.tinyos.net/http://www.zigbee.org/http://grouper.ieee.org/groups/802/dots.htmlhttp://www.ietf.org/html.charters/manet-charter.htmlhttp://www.ietf.org/html.charters/manet-charter.htmlhttp://www.ietf.org/html.charters/manet-charter.htmlhttp://ceng.usc.edu/~anrg/SensorNetBib.htmlhttp://w3.antd.nist.gov/wahn_home.shtml7/31/2019 01 AdHocNet Overview
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Wireless Network Technology
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Ad Hoc Networks vs.
Ad hoc networks vs. Wireless mobile networksInfrastructureless vs. Infrastructured Network
All devices of an ad hoc network are likely to have similarconstraints
Ad hoc networks vs. Peer-to-peer networks
P2P devices use existing networked structures such asInternet
All P2P networks are not ad hoc network
Because NOT all ad hoc network utilize an existing structure forthe 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 theembedded electronic chips
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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 infrastructurenetworks
Started from DARPA PRNet in 1970 Cooperative nodes (wireless)Each node decode-and-forward packets for other nodes
Multi-hop packet forwarding through wirelesslinks
Proactive/reactive/hybrid routing protocolsMost works based on CSMA/CA to solve the
interference problem IEEE 802.11 MAC
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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 SINR
There may be many things out there that we can takeadvantage of across layers for improvement!
F
D
E
C
A
B
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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 connectivityFrequent path breaks due tomobility
High cost and time of deployment Quick and cost-effectivedeployment
Frequency reuse throughgeographical channel reuse
Dynamic frequency reuse basedon CSMA
Time sync: easier to achieve. Difficult and consume BW
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Cellular Net vs. Ad Hoc Net (2)
Cellular Net Ad Hoc Net
BW reservation: easier Requires complex MAC
App. Domain: civilian andcommercial sector
Battlefields, emergency operations,collaborative computing
High cost of net maintenanceSelf-organization and maintenanceis built into net
MHs: low complexity More intelligence
Major goal of routing: max call
acceptance, min call drop
Find paths with min overhead,quick reconfiguration of broken
paths
Widely deployed
Several issues are to be addressedfor commercial deployment,
Widespread use in defense
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Major Applications
Military
Emergency Service
Collaborative and Distributed Computing
Wireless Mesh Network
Wireless Sensor Network
Telematics
Wireless Personal Area Network
Home Network
Ad Hoc Relay for Cellular Network
Networks for ubiquitous computing
Demands for
group
communications
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Emergency Service
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MANET Research Target
MANET
No infrastructure
Self organizing networks
Communications via mobilenodes
Dynamic topologyHeterogeneity bandwidth-
constrained variable-capacity links
Limited physical security
Nodes with limited batterylife and storage capabilities
Issues in MANET
Ad Hoc Unicast Routing
Ad Hoc Multicast/BroadcastRouting
Power Saving
Global Connectivity forMANET
Addressing & DNS Service
Automatic Support ofNetworking in MANET
MANET Autoconfiguration
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WMN Architecture
WMNs (Wireless Mesh Networks) consist of:
mesh routers and mesh clientsMesh routersConventional wireless AP (Access Point) functions
Additional mesh routing functions to support multi-hopcommunications
Usually multiple wireless interfaces built on either the same ordifferent radio technologies
Mesh clientsCan also work as a router for client WMN
Usually one wireless interface
Classification of WMN architecture Infrastructure/Backbone WMNs
Client WMNs
Hybrid WMNs
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Infrastructure/backbone WMNs
Internet
Wi-FiNetworks
CellularNetworks WiMAX
Networks
SensorNetworksBase Station
Sink node
Sensor
Wireless MeshBackbone
Wired ClientsMesh RouterMesh Router
with Gateway
Mesh Router
with 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 WMNs
Mesh Client
Mesh Client
Mesh Client
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Hybrid 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 Model
SourceStimulus
Sink
Sink
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Wireless 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 Hocnetworks 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 andlarge number of sensors
Ad Hoc Net
Wireless
Sensor
Network
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Existing Wireless Net vs. Sensor Net
Cellular system Bluetooth, MANET Sensor Network
Single Hop Multi-hop Multi-hop
High QOS
Bandwidth
efficiency
High QOS Power conservation
Limited bandwidth
Large number ofnode
Narrow radio range
Frequent topologychange
Station to Basestation
Peer to peer
Peer to multi node
Peer to multi node
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Sensor Networks Architecture
Sensor node
Made up of four basic components
Sensing unit, Processing unit, Transceiver unit, and Powerunit
Additional application-dependent components
Location finding system, power generator, and mobilizer
Scattered in a sensor field
Collect 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 Networks
Limited wireless transmission range
Broadcast nature of the wireless medium
Packet losses due to transmission errors
Mobility-induced route changes
Mobility-induced packet losses
Battery constraints
Potentially frequent network partitions
Ease of snooping on wirelesstransmissions (security hazard)
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Issues in Ad Hoc Networks
Medium access scheme
Routing
Multicasting
Transport layer protocol
Pricing shcemeQoS provisioning
Security
Energy management
Addressing and service discovery
Scalability
Deployment considerations
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Medium Access Scheme
Distributed operation
Synchronization Hidden terminal problem Exposed terminal problem Throughput
Access delay Fairness: especially for relaying nodes Real-time traffic support Resource reservationAbility to measure resource availability
Capability for power controlAdaptive rate control Use of directional antennas
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Routing (1)
Challenges
Mobility
results in path breaks, packet collisions, transient loops, stalerouting information, and difficulty in resource reservation
BW constraints
Error-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)
Requirements
Minimum route acquisition delay
Quick route reconfiguration
Loop-free routing
Distributed routing approachMinimum control overhead
Scalability
QoS provisioning
Support for time-sensitive traffic
Security and privacy
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Multicasting
Robusteness
recover and reconfigure quickly from potentialmobility-induced link breaks
Efficiency
Min control overhead
QoS support
Efficient group management
Scalability
security
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Energy Management
Tx power mgmt
MAC: sleep mode
Routing: consider battery life time: load balancing
Transport: reduce ReTx
AppBattery energy mgmt
Extend battery life by taking adv of chemicalproperties, discharge patterns, and by the selection of
a battery from a set of batteriesProcessor power mgmt
Device power mgmt
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Deployment Consideration (1)
Adv. in ad hoc net
Low cont of deployment
Incremental deplyment
Short deplyment time
ReconfigurablityScenario of deployment
Military deployment: data-centric or user-centric
Emergency operation deployment: hend-held,
voice/data, < 100 nodesCommercial wide-area deployment: e.g. WMN
Home network deplyment
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Deployment Consideration (2)
Required longevity of network
Area of coverage
Service availability: redundancy
Operational integration with other infrastructure
Satellite network, UAV(unmanned aerial vehicles), GPS
Cellular network
Choice of protocols
TDMA or CSMA-based MAC?
Geographical routing (using GPS)
Power-saving routing ?
TCP extension ?