Speaker : Dr. Neelesh B. Mehta
Title : Distributed, multiple access based selection schemes for wireless networks
Abstract:
Opportunistic selection arises in several opportunistic wireless communications systems. It is used to exploit multi-user diversity in cellular systems, to select relays in cooperative systems, to improve lifetime in sensor networks, and to speed up message dissemination in vehicular ad hoc networks. In these systems, each node maintains a local preference number called a metric, and the goal is to find the node with the highest metric. The challenge lies in the local nature of the metrics, which 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 investigate a simple and effective timer-based distributed selection scheme. In it, each node maps its metric to a timer and transmits a packet when its timer expires. The key idea is to have nodes with higher metrics set smaller timers, which guarantees that the best node’s timer expires first. However, the timer scheme can fail to select the best node when timers expire too close to one another and collide. We present a series of results about the structure of the optimal timer scheme that maximizes the probability of selecting the best node or even maximizes an end-to-end system performance measure such as net throughput. Extensive bench-marking with several approaches pursued in the literature shows that the optimal schemes can markedly improve performance.
Bio:
Neelesh B. Mehta received his Bachelor of Technology degree in Electronics and Communications Eng. from IIT Madras in 1996, and his M.S. and PhD degrees in Electrical Eng. from the California Institute of Technology, Pasadena, CA, USA in 1997 and 2001, respectively. He is now an Associate Professor in the Dept. of Electrical Communication Eng., Indian Institute of Science (IISc), Bangalore, India. Prior to joining IISc, he was a research scientist in USA in AT&T Laboratories, Broadcom Corp., and Mitsubishi Electric Research Laboratories (MERL) from 2003 to 2007. Neelesh B. Mehta received his Bachelor of Technology degree in Electronics and Communications Eng. from IIT Madras in 1996, and his M.S. and PhD degrees in Electrical Eng. from the California Institute of Technology, Pasadena, CA, USA in 1997 and 2001, respectively. He is now an Associate Professor in the Dept. of Electrical Communication Eng., Indian Institute of Science (IISc), Bangalore, India. Prior to joining IISc, he was a research scientist in USA in AT&T Laboratories, Broadcom Corp., and Mitsubishi Electric Research Laboratories (MERL) from 2003 to 2007.
His research includes work on cellular systems, multiple access protocols, MIMO, energy harvesting, cognitive radio, and cooperative communications. He was also actively involved in the Radio Access Network (RAN1) standardization activities in 3GPP from 2003 to 2007. He was a TPC co-chair for tracks/symposia in COMSNETS 2014, Globecom 2013, ICC 2013, SPCOM 2012, WISARD 2010 and 2011, NCC 2011, VTC 2009 (Fall), and Chinacom 2008. He served as an Editor for the IEEE Transactions on Wireless Communications from 2008 to 2011, and is now an Editor for IEEE Transactions on Communications, IEEE Wireless Communications Letters, and Journal of Communications and Networks. He currently serves as the Director of Conference Publications on the Board of Governors of the IEEE Communications Society.
Date: 25th September, 2013.
Time: 14.00-15.00 hrs
Venue: QMUL Maths:1.03