Date: April 4 (Friday), 10-12 

 

Title: Techniques for Enhancing Channel Sharing in Wireless Network

 

Dr. Nadeem Tamer, Siemens Corporate Research

 

Abstract: During the past several years, the growth in popularity of the
wireless networks has been phenomenal. Because the number of available wireless
channels is limited, as more and more wireless devices are put into service,
overlapped deployments in both space and frequency have become more common.
Since wireless devices must share the use of the communication channel,
efficient channel sharing is critical to the success of emerging applications
of wireless technology, such as Wireless Mesh Networks and Wireless Ad Hoc
Networks. In this talk, I will present two techniques to enhance network
performance. Specifically, the two techniques focus on enhancing the channel
sharing of the wireless network. First, I will present an enhancement
technique to the IEEE 802.11 contention-based scheme that allows more
concurrent transmissions to be scheduled and hence, the communication channel
can be shared more efficiently. I will describe how the IEEE 802.11 standard
is not very efficient in shared channel use due to its overcautious approach
toward assessing the possibility of interference. I will show by piggybacking
additional communication parameters, especially the locations of transmitters
and receivers with each frame, how it is possible for the surrounding
stations to make finer assessment of the channel condition on whether their
own transmissions may indeed corrupt the reception of ongoing transmissions.
Hence, more concurrent transmissions can be scheduled and the communication
channel can be shared more efficiently.  Second, I will present a technique
to estimate the minimum granularity of power control that is useful in
different wireless environments. Power control mechanisms in wireless
networks have been used to reduce interference in the shared channel, thereby
allowing greater re-use and concurrency of communication. However, multipath,
fading, shadowing and external interference from wireless devices, make the
implantation of power control mechanism challenging in practical settings
especially in indoor environments. I will show that fine-grained power
control cannot be effectively used by such algorithms in a systematic manner.
Then I will describe a technique to estimate the appropriate number and
choices of power values that are adequate to implement any robust power
control mechanism in typical indoor environments.

 

Bio: Tamer Nadeem received the PhD degree from the Department of Computer
Science, University of Maryland, College Park, in 2006. He was a member of the
Maryland Information and Network Dynamics Laboratory (MIND) at the University
of Maryland. He is currently a research scientist at Siemens Corporate
Research. His research interests include wireless communications, mobile ad hoc
networks, radio management for enterprise wireless networks, vehicular
networking, pervasive computing, cross layer design protocols, sensor networks,
peer-to-peer systems, and location determination systems. He is a member of
the IEEE, the IEEE Computer Society, and the ACM.