[Nrg-l] PhD Oral Area Exam of Karim Mattar -- Mon 12/18 @ 4pm

Abraham Matta matta at cs.bu.edu
Sat Dec 16 10:08:09 EST 2006

Computer Science Department
Boston University
PhD Candidate: Karim Mattar
Date:  Monday, December 18
Time:  4:00pm
Place: Room MCS 135, 111 Cummington Street 
       (for directions, see www.cs.bu.edu/colloquium)
Title: Cellular Data Networks: Integration Problems,
       Solutions, and Future Directions
Internet users today expect global connectivity anytime from anywhere in
the world. This anywhere-anytime idealogy for Internet access, despite
being grandiose, requires a tremendous infrastructure to provide the
required coverage. Cellular networks do possess such an infrastructure
making their integration with IP a natural next step in the evolution of
the Internet. The result was the birth of cellular data networks---a
hybrid system that poses new networking problems and challenges.

In this talk, I primarily survey recent work dealing with two aspects of
a cellular data network, namely: a) the wireless resource allocation
problem, focusing on solutions to fairly and efficiently share a
time-slotted wireless channel among many users, and b) transport layer
solutions that are optimized for such wireless channels.
With regard to the transport layer, I classify the solutions based on
their primary mechanisms, which are designed to alleviate the effect of:
a) wireless losses, b) mobility/handoff, c) bandwidth asymmetry, and d)
variable rate/delay links. With regard to the wireless resource
allocation problem, I identify three classes of scheduling models, each
with its own assumptions, under which solutions were developed, namely:
a) queue-centric, b) queue-oblivious, and c) adversarial models.  

I will argue that none of the existing transport layer solutions are
adequate for time-slotted wireless channels that employ sophisticated
channel-aware schedulers and are notorious for having highly variable
rates and delays. I will also discuss the possibility of developing
transport layer solutions that specifically deal with adversarial
channel models that capture the effect of worst-case channel behaviors.
The exposition of the resource allocation and transport problems
naturally leads to discussing potential directions for composing the two
components safely and efficiently.

Examination Committee: 
Ibrahim Matta
Azer Bestavros
John Byers
Mark Crovella

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