TONIGHT - (seb) Comedy Hour: Rob Maher
Wednesday, April 11 at 9:00pm ]]>
EE Graduate Seminar
On Far-End Crosstalk Mitigation in VDSL Systems
Dr. Amitkumar Mahadevan
Ikanos Communications Inc., Red Bank, NJ
11:30am-12:45pm, Friday 13 April 2012, ITE 237, UMBC
Very-high-speed digital subscriber line (VDSL) is a last mile communications access solution that exploits the existing copper infrastructure to deliver high-speed internet access to homes and businesses. Far-end crosstalk (FEXT), i.e., interference seen at a VDSL receiver due to leakage from extraneous transmitters located at the other end (far end) of the line, is by far the most dominant impairment in VDSL. Left untreated, FEXT results in a considerable reduction in the service rates than can be delivered to users, or equivalently, a considerable reduction in the range over which a given service rate can be guaranteed. In this presentation, we will discuss the characteristics of FEXT in DSL systems and techniques employed in the industry to mitigate the impact of FEXT. Substantial attention will be devoted to 'vectoring': a per-frequency active FEXT mitigation scheme involving signal cooperation across different users at the central-office end of the system.
By design, vectoring necessitates the use of a pre-coder for downstream FEXT mitigation and a post-canceller for upstream FEXT mitigation. Low-complexity adaptive schemes for estimating the off-diagonal downstream FEXT pre-coder and the upstream FEXT canceller based on independent minimization of the per-frequency user error variances will be presented. These schemes do not involve any matrix inversion and are shown to achieve almost FEXT-free performance. We will also discuss key features of the recently published G.vector (G.993.5) ITU standard that allows for rapid and non-disruptive estimation of new elements of the pre-coder and canceller matrices when users join the vectored system.
Short Bio: Amitkumar Mahadevan was born in Mumbai, India. He received the B.E. degree in electrical engineering in 1998 from Sardar Patel College of Engineering, Mumbai University, India, and the MSEE degree in 2002 and the Ph.D. (EE) degree in 2005 from UMBC. In 2005, he joined Conexant Systems Inc., Red Bank, NJ, (now Ikanos Communications, Inc.) as a firmware engineer and has worked on advanced technology development for various flavors of DSL communication systems. More recently, he has been working on algorithm development and implementation for active crosstalk cancellation or 'vectoring' in VDSL systems. His research interests include discrete multi-tone and orthogonal frequency-division-multiplexing based communication systems, error correction codes, importance sampling techniques, and quantum information theory.
Host: Prof. Joel M. Morris
]]>Volunteer to help staff the UMBC booth with interactive ITE activities at the U.S. Science and Engineering Festival in Washington, DC on Sunday, April 29th! This is the first year UMBC will have our own booth there, so COEIT student organizations will be working together to staff the booth on Sunday, April 29th from 10am-4pm. Volunteers will do hands-on-activities with hundreds of children who are at the festival! http://www.usasciencefestival.org/
Round trip van transportation will be provided from UMBC and lunch will be provided. You have the option of volunteering the entire time, or working at the booth for half the time and spending the other half perusing the hundreds of booths at the fair. Many large and small ITE companies, schools, and organizations will be present, so it would be a great networking opportunity. Invite your ITE friends & CWIT Affiliates as well!
More details are forthcoming. If you are interested in volunteering, email me, Susan Martin susan@umbc.edu, so that I can add you to the list of volunteers for Sunday from 10 am-4 pm, and get more details out to you after the planning meeting next week.
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]]>Fun.: Why Am I The One (Acoustic)
Fun. perform an acoustic version of ‘Why Am I The One’ from the album Some Nights. This acoustic version of the song will be available on a limited edition 10” vinyl single available on Record Store Day (April 21st). Click HERE for more information about that release.