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报告题目：Timer-based distributed selection schemes for opportunistic wireless networks
报告时间：2013年4月11日（星期四）4:00pm~5:00pm
报告地点：信电大楼-215学术厅
报告人：Prof. Neelesh B. Mehta
Indian Institute of Science (IISc)
Abstract
Opportunistic selection arises in several wireless communications systems. It is used to exploit multi-user diversity in cellular systems, to exploit spatial diversity in cooperative relay networks, to improve lifetime in sensor networks, and to speed up message dissemination in vehicular ad hoc networks. In all of these systems, each node maintains a local preference number called a metric. The sink uses a selection algorithm to find the ‘best’ node with the largest metric. The local nature of the metrics requires the selection process to be distributed and reliable. Further, the selection needs to be fast in order to increase the fraction of time available for data transmission using the selected node and to handle time-varying channels.
We delve deep into the popular and simple timer-based multiple access distributed selection scheme. In it, each node maps its metric to a timer and transmits a packet when its timer expires. The scheme guarantees that nodes with higher metrics set lower timers. However, the timer scheme can fail to select the best node when timers expire too close to one another and collide. We show that the optimal timer scheme that maximizes the probability of selecting the best node has a practically appealing discrete structure, and is different from the ad hoc timer schemes used in the literature. We then address the problem of contention resolution in a timer scheme. To this end, we propose a novel, feedback overhead-aware selection scheme that combines the best features of the timer scheme and the classical splitting-based selection scheme. Extensive benchmarking with several approaches pursued in the literature shows that the proposed optimal schemes can improve performance significantly.
Biography
Neelesh B. Mehta is an Associate Professor in the Dept. of Electrical Communication Engineering at the Indian Institute of Science, Bangalore, India. He received his Bachelor of Technology degree in Electronics and Communications Engineering from the Indian Institute of Technology (IIT), Madras in 1996, and his M.S. and Ph.D. degrees in Electrical Engineering from the California Institute of Technology, Pasadena, CA, USA in 1997 and 2001, respectively. Prior to joining IISc in 2007, he served as a research scientist from 2001-2007 in AT&T Laboratories, USA, Broadcom Corp., USA, and Mitsubishi Electric Research Laboratories, USA. His research includes work on link adaptation, multiple access protocols, cellular systems, MIMO, cognitive radio, energy harvesting wireless systems, and cooperative communications. He was also actively involved in the Radio Access Network (RAN1) standardization activities in 3GPP from 2003 to 2007. He has co-authored 40+ IEEE journal papers, 65+ conference papers, and three book chapters, and is a co-inventor in 20 issued US patents. He served as an Editor for the IEEE Transactions on Wireless Communications from 2008 to 2011, and is now an Editor for IEEE Wireless Communications Letters and the Journal of Communications and Networks. He currently serves as the Director of Conference Publications on the Board of Governors of the IEEE Communications Society.
