[Nrg-l] Kave Salamatian visit Tuesday December 14

Mark Crovella crovella at cs.bu.edu
Thu Dec 9 13:18:52 EST 2004


When it rains it pours!   The day after Ion Stoica, we will host Kave
Salamatian (Tuesday, Dec 14).   Kave is at LIP6, U. Paris VI.   He
specializes in applied probability and information theory applied to
networking.

He will give a talk on his recent work at 2pm in the grad lounge.
Title and abstract are below.   Please let me know if you'd like to meet
with him - he will be here all day.

See you then,
Mark
--
Title: A network coding based approach for Communication in AdHoc/sensor
networks

Wireless networks consist of senders, receivers and intermediate nodes
that collaborate (more or less) to communicate with each others. Most of
the researches in the domain of wireless network have focused on routing
based approaches where the wireless network is reduced as a dynamic
graph and a minimum cost routing mechanism is applied. These approaches
have lead to several routing mechanisms as OLSR (Optimized Link State
Routing Protocol), AODV (Ad hoc On Demand Distance Vector). 
However the fundamental nature of wireless network is broadcast, meaning
that every transmission is potentially received by all tuned receivers.
This basic property is not well captured by graph based approaches where
packets follow a single path from sender to receiver. Using the
multipath approaches have been very attractive, however Optimal
MultiPath routing have shown to be NP-Complete and on the other extreme
packet flooding approaches that also use all the available capacity in
the wireless network are very wasteful of energy.  

In this presentation we will present an approach that tries to benefit
from the overall capacity inside the network without flooding it with
redundant packets. The proposed approach is rooted in Information
theory. It is based on collaboration of intermediate relays at network
layer to forward useful side information in place of dumbly forwarding
packets. We will show in this paper the information theoretic bounds and
show that they are achievable using practical codes. The practical
coding scheme is presented for the general case of multiple intermediate
nodes. The proposed coding scheme is simulated in realistic scenarios
and the obtained results show a remarkable improvement in throughput and
relay load compared to network using classical routing approach.



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