Computational Complexity of Decoding Orthogonal Space-Time Block Codes

Featuring Ender Ayanoglu, Ph.D.
Professor, Electrical Engineering and Computer Science
Director, Center for Pervasive Communications and Computing
The Henry Samueli School of Engineering, UC Irvine

Location:  2430 Engineering Hall (Colloquium Room)
Free and open to the public

Abstract:
Orthogonal Space-Time Block Codes (OSTBCs) have been around for more than a decade. It is well-known that the orthogonality properties of OSTBCs lead to their decoding on a symbol-by-symbol decoupled basis. In the original OSTBC papers, a metric which provides this decoupling is introduced. Furthermore, basic Maximum Likelihood techniques have been employed by several authors to come up with a number of other decoding metrics.  In this talk, we will quantify the computational complexity of decoding OSTBCs. We will unify the approaches from the literature and will show four equivalent metrics which have the same computational complexity. We will compare these metrics with the one in the original OSTBC papers and show that, with a slight change, they become equivalent. Finally we will provide a version of the optimal metric where the division operation is avoided and the computational complexity is minimum. We will also discuss the computational complexity of a number of OSTBC examples and calculate their computational complexity. We will explain when the computational complexity is substantially reduced.

About the Speaker:                           
Ender Ayanoglu earned a Ph.D. degree from Stanford University, 1986, in electrical engineering.  He was with the Communications Systems Research Laboratory of AT&T Bell Laboratories (Bell Labs, Lucent Technologies after 1996) until 1999 and was with Cisco Systems until 2002. Since 2002, he has been a professor in the Department of Electrical Engineering and Computer Science in The Henry Samueli School of Engineering, University of California, Irvine, where he is currently the Director of the Center for Pervasive Communications and Computing and holds the Conexant-Broadcom Endowed Chair. Ayanoglu is the recipient of the Institute of Electrical and Eelectronics Engineers (IEEE) Communications Society Stephen O. Rice Prize Paper Award in 1995 and the IEEE Communications Society Best Tutorial  Paper Award in 1997. He has been an editor of the IEEE Transactions on Communications since 1993, and from 2004 to 2008 served as its editor-in-chief. He served on the Executive Committee of the IEEE Communications Society Communication Theory Committee from 1990 until 2002, and from 1999 to 2002, was its chair.