Transcript
PRASAD ENGINEERING COLLEGE
PAPER ON
MOBILE AD-HOC NETWORK
Presented by
K.ASHWINI 096L1A0404
A.DIVYAJYOTHI 096L1A0405
III YEAR
ELECTRONICS AND COMMUNICATION ENGINEERING
INTRODUCTIONINTRODUCTION
• Mobile wireless networks are popular in 1970sMobile wireless networks are popular in 1970s
• There are currently two variations of mobile wireless There are currently two variations of mobile wireless networknetwork
• Infrastructure network Infrastructure network
• Ad-hoc networkAd-hoc network
Why Ad Hoc Networks ?Why Ad Hoc Networks ?
• Setting up of fixed access points and backbone infrastructure is not always viable
– Infrastructure may not be present in a disaster area or war zone
– Infrastructure may not be practical for short range radios; Bluetooth (range ~ 10m)
• Ad hoc networks:
– Do not need backbone infrastructure support
– Are easy to deploy
– Useful when infrastructure is absent, destroyed or impractical
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What is an Ad hoc Network
• Collection of mobile wireless nodes forming a network without the aid of any infrastructure or centralized administration
• Nodes have limited transmission range• Nodes act as a routers
WHY WE GO FOR MANET?
The wired network is not available and multi-hop wireless networks provide
The only feasible means for communication and information access
Ex: Battlefield communications,disaster recovery etc
MANET: Mobile Ad hoc Networks
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A collection of wireless mobile nodes dynamically forming a network without any existing infrastructure and the relative position dictate communication links (dynamically changing).
From DARPA Website
Battle field communication8
May need to traverse multiple links to reach destination
Mobility causes route changes
Circles shown the coverage area of various laptop computers
Node A wants to transmit packet to Node D,But D is not coverage area of Node A
It sends packet to node D via the Node C
Interference in MANET
• In a wired network, every link may be utilized simultaneously
• On the other hand, neighboring links in an Ad-hoc network interfere with each other
• The interference range is typically much larger than the transmission range.
Implementation of backoff
• It has been observed that the widely used exponential backoff mechanism (e.g., IEEE 802.11)
• is unfair towards nodes in the middle of an Ad-Hoc network with multiple interference domains.
• Hence the unfairness is illustrated and the Impatient Backoff Algorithm is proposed
Routing ProtocolsRouting Protocols Proactive protocols Proactive protocols
– – Traditional distributed shortest path protocolsTraditional distributed shortest path protocols
– – Maintain routes between every host pair at all timesMaintain routes between every host pair at all times
– – Based on periodic updates; High routing overheadBased on periodic updates; High routing overhead
– – Example: DSDV (destination sequenced distance vector)Example: DSDV (destination sequenced distance vector)
Reactive protocolsReactive protocols
– – Determine route if and when neededDetermine route if and when needed
– – Source initiates route discoverySource initiates route discovery
– – Example: DSR (dynamic source routing)Example: DSR (dynamic source routing)
Hybrid protocolsHybrid protocols
– – Adaptive; Combination of proactive and reactiveAdaptive; Combination of proactive and reactive
– – Example : ZRP (zone routing protocol)Example : ZRP (zone routing protocol)
Routing in MANET
• Routing is one of the primary function of MANET
• The development of efficient routing protocols is nontrivial interface etc
• These routing protocol may generally be categorized as two types
» Table-driven» Source-initiated (demand-driven)
Routing in MANETRouting in MANET
Ad-hoc Routing Protocols
Table-driven Source-initiated on-demand
DSDV WRP AODV DSR LMR ABR
CGSRTORA SSR
MANET
Characteristics Dynamic topologies Limited channel bandwidth Variable capacity links Energy-constrained operation Limited physical security
Applications Military battlefield networks Personal Area Networks (PAN) Disaster and rescue operation Peer to peer networks Video gaming
MANET usage areas & limitations
Military scenariosSensor networksRescue operationsStudents on campusFree internet connection sharingConferencesThe coverage area of ad-hoc network is 500
square meter
Variable Bandwidth Disconnected Operation Limited Power
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Power Consumption18
Limited Power Source
Battery Lifetime is limited
Each sensor node plays a dual role of data
originator and data router (data processor)
The malfunctioning of a few nodes consumes
lot of energy (rerouting of packets and
significant topological changes)
Conclusion
Other interesting problems: Applications for MANET Address assignment Qos issues Improving interaction between protocol layers
REFERENCES
http://ieee.ieeexplore.org/ [1]. Rajarshi Gupta, Zhanfeng Jia, “Interference-aware QoS Routing (IQ
Routing) for Ad-Hoc Networks”, published in the proceedings of National conference, held at Jawaharlal Nehru National College of Engineering, Shimoga on 7-8 July 2006
[2]. IEEE Standard for Wireless LAN Medium Access Control (MAC) and Physical layer (PHY) Specifications, Nov. 1997. P802.11
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Any Questions?
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