Things you never knew you could do with EXIT charts

Speaker: Dr. Jossy Sayir, Vienna Research Center for Telecommunications (FTW)
Abstract: Extrinsic Information Transfer (EXIT) charts were introduced by S. ten Brink to visualize the decoding process in an iterative decoder, and to design low-density parity-check (LDPC) codes for a wide range of communication scenarios. This talk focuses on two applications. First, EXIT charts are used to analyze sub-optimal decoders. The result is initially disappointing, because the EXIT charts fail to predict the performance accurately. When interpreted correctly, we discover that they signal that a minor modification of the decoder can improve the performance to the predicted level at almost no increase in complexity. Second, EXIT charts are used to design LDPC codes for receivers that iterate over the decoder and a "receiver frontend", e.g., a de-mapper, a MIMO detector, etc. One approach, by S. ten Brink, Kramer and Ashikhmin, earned them the 2004 Stephen O. Rice Prize. Our approach matches the overall EXIT curve of the LDPC decoder to the EXIT curve of the frontend. This eliminates the need for an analytical _expression of the frontend EXIT curve. Furthermore, the code parameters obtained are robust to small variations, making them suitable for practical applications and for moderate length codes. This is joint work with Gottfried Lechner and Ingmar Land.
Biography: Dr. Jossy Sayir received his Dipl. El.-Ing. degree from the ETH Zurich in 1991. From 1991 to 1993, he worked as a development engineer for Motorola Communications in Tel Aviv, Israel, contributing to the design of the first digital mobile radio system ever produced by Motorola. He returned to ETH from 1993 to 1999, getting his PhD in 1999 under the supervision of Prof. J.L. Massey. The title of his thesis is "On Coding by Probability Transformation". Since 2000, he has been employed at the Telecommunications Research Center (FTW) in Vienna, Austria, as a senior researcher. His research interests include iterative decoding methods, joint source and channel coding, numerical capacity computation algorithms, Markov sources, and wireless ad hoc and sensor networks. Since July 2002, he manages part of the strategic research activities at FTW and supervises a group of researchers. He has taught courses on Turbo and related codes at Vienna University of Technology and at the University of Aalborg, Denmark. He has served on the organization committees of several international conferences and workshops. In his spare time, he loves to cook, and plays the alto saxophone in various jazz ensembles.
Presentation On: Friday,3 March, 2006,
11:00 a.m. in room 1115, CSIC
Videotape: <Not available.>