Neighbor-Aware Schemes for IEEE 802.11-based wireless Networks

Tamer Nadeem
                                                            Siemens Corporate Research

Date: June 1, 2010 (Tuesday)

Place: E & C S BUILDING Auditorium (1st Floor)

TIME: 10:00 (DONUTS) 10:10 (TALK)

Wireless networks present unusual challenges since they are
characterized by unpredictable connectivity and widely varying
bandwidth. A wireless node can experience rapid and large-scale changes
in bandwidth availability. If a node does not adapt its network
communication to these changes, it suffers from performance degradation.
However, nodes adapt according to their best interests that may conflict
with neighbor nodes' objectives. Therefore, nodes need to observe the
behavior of their neighbors and dynamically adapt their performance
according to neighbors' behavior (neighbor-aware) in addition to network
conditions. Schemes that monitor and collect information about their
neighbors and then be able to adjust their behavior based on the
collected information are called neighbor-aware schemes. 

In this talk, I will present neighbor-aware schemes in the context of
two different IEEE 802.11 network environments. In the first part of my
talk, I will present MORAL (Multi-user data Rate Adjustment aLgorithm)
scheme that utilizes the retry limit parameter of IEEE 802.11 networks
and dynamically adjust this parameter according to the channel
characteristics observed and the neighbor information gathered from
communications in order to guarantee fairness and network performance
accordingly. In wireless ad hoc network, cooperation among nodes for
packet forwarding is essential to the survival of an ad hoc network. If
nodes refuse to cooperate in packet forwarding, end-to-end packet
delivery may not be possible. Such uncooperative behavior can greatly
degrade network performance and may even result in total communication
breakdown. Reputation management systems have been proposed as a
cooperation enforcement solution in ad hoc networks. However, the
dynamic nature of ad hoc networks causes node behavior to vary both
spatially and temporally due to changes in the local and network-wide
conditions. When reputation management functions do not adapt to such
changes, their effectiveness, measured in terms of accuracy (correct
identification of node behavior) and promptness (timely identification
of node misbehavior), may be compromised. 

In the second part of my talk, I will present an adaptive reputation
management system that observes neighbors' cooperative behavior and
realizes that changes in node behavior may be driven by changes in
network conditions, and then accommodates such changes by adapting its
operating parameters.

Biography:
Tamer Nadeem received the Ph.D. degree from the University of Maryland,
College Park, in 2006. He is currently a Research Scientist with Siemens
Corporate Research, Inc., Princeton, NJ. His research interest includes
radio management for wireless networks, vehicular networking, pervasive
computing, sensor networks, and peer-to-peer systems. He has published
more than 40 technical papers in refereed conferences and journals
including the Journal on Selected Areas of Communication (JSAC), the
IEEE Transaction on Mobile Computing, the IEEE Infocom, and the
Association for Computing Machinery (ACM) International Measurement
Conference (IMC). Dr. Nadeem is a member of the ACM, the IEEE Computer
Society, and the IEEE Communication Society.