Constant Weight Codes, Geometry and Optical Networks

February 27, 2009
EE Conference Room (Mudd 1301)
Hosted by: Prof. Xiaodong Wang
Speaker: Vinay A. Vaishampayan, AT&T Labs-Research


I will describe an interesting layered communication problem that arose within the context of optical network management. Thegoal was to design a system that would enable a network management system to acquire configuration data in a large optically routed fiber network. Cost and speed constraints led to a layered architecture which used CDMA and constant weight codes in order to create a special management channel that rides on top of a very high rate data channel. In the first part of the talk I will describe the design and performance of this system. This system, called LightLabelat AT&T, was featured in a Telephony Online article last year.

During the process of implementing this system we realized that the current state constant weight codes needed advancement. In the second part of the talk I will describe our resulting work on constant weight codes, where we view the problem as that ofdissecting polytopesin Euclidean space. This line of investigation has opened the door to a beautiful area of geometry and I will describe new techniques for encoding and decoding that this has led to.


Vinay A. Vaishampayan works on interesting problems in the areas of signal processing, communications and coding at AT&T Labs-Research, where he heads the communication sciences research program. Before joining AT&T he taught Electrical Engineering at Texas A&M University. He has a PhD degree in Electrical Engineering from the University of Maryland and a B. Tech degree, also in Electrical Engineering, from the Indian Institute of Technology, Delhi.

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