L. Venkata Subramaniam

Dr. L. Venkata Subramaniam

IBM, Solutions Research Center

Delhi, India

Thursday, September 17, 1998
4:30 - 5:30 PM
1311 EECS

On Codes over Asymmetric PSK and Multidimensional Uniform Signal Set

Abstract -

We look closely at the code design criteria for fading channels (maximizing effective length and product distance). Based on these results, trellis coded modulation using asymmetric PSK signal sets for fading channels are considered. Simulation results are presented to show that improved performance may be obtained.

For the AWGN channel when using codes over M-ary signal constellations the performance depends on the square of their minimum Euclidean distance. We obtain a lower achievable asymptotic bound for Euclidean space codes over uniform signal sets (a signal set in which the distance profile looking from any signal point is the same). We obtain bounds for a number of 2, 3 and 4 dimensional signal sets and compare them based on the bound.

Biosketch -

1991, B.E. in Electronics and Communication Engg. from University of Mysore, India.
1993, M.S. in Electrical Engineering from Washington Univ., St. Louis, USA.
1998, Ph.D. from Indian Institute of Technology (IIT), Delhi, India.

Since July 1998 working in IBM, Solutions Research Center, Delhi, India, as a technical staff member.
Currently visiting IBM, T. J. Watson Research Center in Yorktown Heights, NY, USA.

Currently working on multimodal speech recognition problems.

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