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M. Faloutsos UC Riverside1 Open Problems: What should you work on for the next 4 years? Fred Baker, Fellow CISCO Bob Briscoe, British Telecom George Varghese,

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Presentation on theme: "M. Faloutsos UC Riverside1 Open Problems: What should you work on for the next 4 years? Fred Baker, Fellow CISCO Bob Briscoe, British Telecom George Varghese,"— Presentation transcript:

1 M. Faloutsos UC Riverside1 Open Problems: What should you work on for the next 4 years? Fred Baker, Fellow CISCO Bob Briscoe, British Telecom George Varghese, UCSD/ entrepreneur John Wroclawski, ISI Networking Director Facilitator: Michalis Faloutsos, UCR ICNP Panel

2 M. Faloutsos UC Riverside 2 We wish a quick recovery…  to Darleen Fischer (NSF)  who would have been here  but cannot due to non-threatening health reasons

3 M. Faloutsos UC Riverside 3 The Goal is to Provoke  Provoking is an essential human function I provoke, therefore I think, therefore I exist  A good panel should result in a fist-fight  Conclusion: We need controversy

4 M. Faloutsos UC Riverside 4 My First Choices for the Panel

5 M. Faloutsos UC Riverside 5 Final Panel  Fred Baker, Fellow CISCO  Bob Briscoe, British Telecom  George Varghese, UCSD/ entrepreneur  John Wroclawski, ISI Networking Director Alphabetical Order

6 M. Faloutsos UC Riverside 6 The Focus of the Panel  The most exciting idea you have read recently  The right area for a new researcher to tackle  A problem the community should solve You would give money for the research You would invest in the start up You would give $20 out of your pocket  A technology or user trend that will make a splash in 2-5 years

7 M. Faloutsos UC Riverside 7 Playing the Devil’s Advocate

8 M. Faloutsos UC Riverside 8 My Challenge to the Panel:  Everything important has already been discovered  We are not reinventing, just renaming  Let the industry do the research it needs  Academia is consumed by paper-o-lagnia Greek: Lagnia = desire, lust for  We should all change professions

9 M. Faloutsos UC Riverside 9 Something New and Cool  I ‘d give $20 to see it fully implemented

10 M. Faloutsos UC Riverside 10 Cooperative Diversity in ad hoc networks  “United we transmit” A B

11 M. Faloutsos UC Riverside 11 Synchronous Tx = Contention  So far, overlapping transmissions = BAD Hidden and exposed terminals Self-contention: packets of the same flow  Current Focus: reduce contention A B CD B A D C

12 M. Faloutsos UC Riverside 12 Cooperative Diversity: A Paradigm Shift  Cooperation instead of Contention  A phy breakthrough  Multiple transmissions can be combined at the receiver  Not only they don’t cancel out  They improve the success of transmission! A B Node A cooperates with neighbors to send the same packet to B

13 M. Faloutsos UC Riverside 13 Cooperative Diversity: Essentials  Solicit/select the cooperation of neighbors  Provide the cooperating neighbors with a copy of the data packet.  Ensure that the receiver has CSI for the links to every cooperating node. A B Node A cooperates with neighbors to send the same packet to B

14 M. Faloutsos UC Riverside 14 Cooperative Diversity is Counter Intuitive  Transmission range is longer than interference range! The transmissions range is increased by a factor of 5.4 The interference range by a factor of 1.7 For diversity gain 15 dB, path loss 3, BER 10^-3 A B C Coop Interference

15 M. Faloutsos UC Riverside 15 1.What Cooperation Buys Us 1. We can “shorten” our paths SD SID 2. Path using cooperative diversity

16 M. Faloutsos UC Riverside What Cooperation Buys Us  Can bridge gaps in sparse networks Connect disconnected networks  Enable weak-device networks The sensor network reach-back problem Many sensors cooperate to reach the sink!

17 M. Faloutsos UC Riverside 17 Can this translate to network performance?  Phy layer has been well studied  Recently efforts show big gains in higher layer performance  Implementation is pending… Cooperative Performance is red Thruput Delay

18 M. Faloutsos UC Riverside 18 If you want to see more:  J.N.Laneman, “Cooperative diversity in wireless networks: Algorithms and architectures”, Ph.D. Thesis, Massachusetts Institute of Technology, August  G. Jakllari et al. "A Cross-Layer Framework for Exploiting Virtual MISO Links in Mobile Ad hoc Networks" IEEE Transactions on Mobile Computing to appear.  G. Jakllari et al. "On Broadcasting with Cooperative Diversity in Multi-hop Wireless Networks ” IEEE JSAC to appear.  A. Khandani, et al. “Cooperative routing in wireless networks.”, Allerton Conference on Communications, Control and Computing, October  X, Li, Space-Time Coded Multi-Transmission Among Distributed Transmitters without Perfect Synchronization, IEEE Signal Processing Letters, 11(12), December  A. Sendonaris et al. “User Cooperation Diversity--Part II: Implementation Aspects and Performance Analysis”, IEEE Transactions on Communications, 51(11), November 2003.

19 M. Faloutsos UC Riverside 19 Thank You!


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