DSP/COMMUNICATIONS SEMINAR

SPEAKER:  Prof.  Gottfried Ungerboeck
	  IBM Zurich Research Laboratory
	  Zurich, SWITZERLAND


TITLE: 	  ``NETWORK ACCESS TECHNOLOGIES - AN OVERVIEW"

DATE:     Monday, March 16, 1998
TIME:     4:00 p.m.
PLACE:    Room B02 C&SRL 
          NOTE: CHANGE IN ROOM

OPEN TO THE PUBLIC



ABSTRACT - The technical direction for the global telecommunication networks
appears to be relatively clear: use of optical transmission, SDH transport,
a mixture of STM and ATM switching, and finally IP. The situation is less
clear for the access networks, which are needed to span the last mile
between the entry points to the core networks and the end-users. While
optical transmission is introduced between network entry points and local
service delivery nodes, the last-leg links to the end users will continue
to be based on existing twisted-pair or coaxial cables. With modern
transceiver technologies, these cables support digital transmission at much
higher rates than believed possible only a few years ago. Where copper
cables are not available or practical, wireless access links are
introduced.
   The existing and emerging network access technologies will be reviewed
with an emphasis on physical layer transmission. Specifically, recent
developments in `56 kbit/s' voiceband modems, digital subscriber line
technologies (xDSLs: basic- and primary-rate ISDN, ADSL, VDSL), two-way
hybrid fiber cable (HFC) systems and cable modems, and radio access systems
will be discussed. Advances in high-speed transceivers for local-area
networking will also be addressed.



BIOGRAPHY - Gottfried Ungerboeck received the Dipl.Ing. degree from the 
Technical University in Vienna in 1964 and the Ph.D. degree from the 
Swiss Federal Institute of Technology in Zurich in 1970, both in Electrical 
Engineering.  In 1967 he joined the IBM Zurich Research Laboratory in 
Rueschlikon, Switzerland. His initial work dealt with digital speech 
processing and switching systems. Later he turned to communication and 
information theory.  During the mid 70's he began to explore the potential 
of combining coding and modulation. He also developed digital signal 
processors and engaged in their applications. His applied work concentrated 
on voiceband modems, satellite transmission, magnetic recording, and more 
recently on LAN transceivers and cable modems. Since 1978 he has managed 
signal-processing activities at the IBM Zurich Research Laboratory. His 
present work concentrates on access technologies for "spanning the last mile" 
via copper. Dr. Ungerboeck is an IBM Fellow, an IEEE Fellow, and a Foreign
Associate of the National Academy of Engineering (USA). Throughout his
career he has served for 14 years as an Associate Editor of IEEE
Transactions on Communications. He has been awarded the 1984 IEEE
Information Theory Group Prize Paper Award. Recent recognitions include the
1994 IEEE Richard W. Hamming Medal, the 1994 Eduard Rhein Basic Science
Award (jointly with A. J. Viterbi), the 1996 Marconi International
Fellowship Award, and the 1997 Australia Prize (jointly with A. Snyder and
R. Tucker).