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Localized Algorithms and Their Applications in Ad Hoc Wireless Networks. Jie Wu Dept. of Computer Science & Engineering Florida Atlantic University Boca Raton, FL 33431. Classification of Communication Networks. Wired Networks LAN, MAN, WAN, and Internet Wireless Networks
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Localized Algorithms and Their Applications in Ad Hoc Wireless Networks Jie Wu Dept. of Computer Science & Engineering Florida Atlantic University Boca Raton, FL 33431 CNSF Workshop
Classification of Communication Networks • Wired Networks • LAN, MAN, WAN, and Internet • Wireless Networks • Infrastructured networks (cellular networks) • Infrastructureless networks (ad hoc wireless networks) CNSF Workshop
Wired/Wireless Networks CNSF Workshop
Wireless and Mobile Networks • 200 million wireless telephone handsets (purchased annually) • A billion wireless communication devices in use • The first decade of 21st Century: mobile computing • "anytime, anywhere" CNSF Workshop
Characteristics • Self-organizing: without centralized control • Scarce resources: bandwidth and batteries • Dynamic network topology • Unit disk graph models: host connection based on geographical distance CNSF Workshop
Unit Disk Graph A simple ad hoc wireless network of six wireless mobile hosts. CNSF Workshop
Major Issues in Ad Hoc Networks • Mobility management • Addressing and routing • Location tracking • Absolute vs. Relative, GPS • Network management • Merge and split • Resource management • Network resource allocation and energy efficiency • QoS management • Dynamic advance reservation and adaptive error control techniques CNSF Workshop
Major Issues in Ad Hoc Networks (Cont’d.) • MAC protocols • Contention-base, controlled • Applications and middleware • Measurement and experimentation • Security • Authentication, encryption, anonymity, and intrusion detection • Error control and failure • Error correction and retransmission, deployment of back-up systems CNSF Workshop
Localized Algorithms (Estrin, 99) • Processors (hosts) only interact with others in a restricted vicinity. • Each processor performs exceedingly simple tasks (such as maintaining and propagating information markers). • Collectively these processors achieve a desired global objective. • There is no (or limited) sequential propagation of information. CNSF Workshop
Localized Algorithms (Con’t) • Differ from traditional distributed algorithms • Complexity • Communication: number of rounds • Communication: size of message • Computation: plays a lesser rule • Quality • Average case: probabilistic analysis/simulation • Worst case: bound/approximation ratio CNSF Workshop
Application I: Connected Dominating Set (CDS) (Wu and Li, 1999) • CDS as a virtual backbone • Marking process: A node is marked true if it has two unconnected neighbors . CNSF Workshop
Marking Process (Cont’d.) A sample ad hoc wireless network CNSF Workshop
u w s v (a) Application II: Broadcasting(Wu and Dai, 2003 and 2004) • Promiscuous receive mode • Coverage & efficiency • Flooding: each node forwards the message once u u w s w s v v (c) (b) CNSF Workshop
Application II: Broadcasting (Con’t) • Localized solution via self-pruning • (INFOCOM 2003) • Localized solution via neighbor designation • (ICDCS 2003) • Mobility management and consistent view • (INFOCOM 2004) • Computation complexity reduction in dense mode (ICDCS 2004) CNSF Workshop
A Sample Broadcasting(n=100, d=6, r=16, k=2) CNSF Workshop
Other Applications • Energy-Efficient Communication • MAC layer protocols • Topology control • Directional antenna • Sensor coverage • Data gathering and dissemination • … CNSF Workshop
Security in Ad Hoc Networks • Key management • Routing security • Light-weight cryptography • Intrusion detection • Trust: incentive-based CNSF Workshop
Cross-Disciplinary Issues • NSF Sensor Network Program (March, 2003) • Sponsored by multiple divisions/programs (including CISE) • Encouraging multi-disciplinary team effort • 1,000 submissions with an acceptance rate of around 5% CNSF Workshop
Example: Multi-Disciplinary Team • Hitch-hiking Model (INFOCOM 2004) • Energy-efficient design in sensor networks • Multiple institutions: UMass- FAU • Multiple disciplines • physical layer • MAC layer • network layer CNSF Workshop
Vision of the Field • Convergence of Multiple Disciplines • Parallel processing • Distributed systems • Network computing • Wireless network and mobile computing as an important component in Cyberinfrastructure and Cybertrust CNSF Workshop
Vision of the Field Ultimate Cyberinfrastructure • Petascale computing, exabyte storage, and terabit networks Network-Centric • Supernetworks: networks are faster than the computers attached to them • Endpoints scale to bandwidth-match the network with multiple-10Gbps lambdas CNSF Workshop
Major Conferences in the fields • General: IEEE INFOCOM • Mobile Computing: ACM MobiCom • Ad Hoc Networks: ACM MobiHoc • Distributed Systems: IEEE ICDCS • Sensor Networks: IEEE MASS (Mobile Ad-hoc and Sensor Networks) CNSF Workshop
Some Related Events • IEEE Computer • Special issue on Ad Hoc Networking • Feb. 2004, guest editors: J. Wu. & I. Stojmenovic • NSF Workshop on Theoretical Aspects of Ad hoc, Sensor, and Peer-to-Peer Networks • Feb. 2004, http://www.cse.fau.edu/~jie • Book published by CRC and special issue in JPDC CNSF Workshop