John M. Cioffi - US grants

This grant provides support to Prof. John Cioffi under the Foundation's Presidential Young Investigator (PYI) program. This research concerns the digital signal processing implementation of communication systems. Specifically much of the work concerns algorithms for adaptive filtering for data transmission. Such adaptive filtering is quite useful for obtaining the highest data rates on the largely unknown but slowly varying environment which is the typical communications line. The adaptive filters slowly track this variation and then alter the transmitted signals so as to maintain maximum thruput. The PYI Awards program provides research support to the Nation's most outstanding and promising young science and engineering faculty. The awards are intended to improve the capability of U. S. academic institutions to respond to the demand for highly qualified science and engineering personnel for academic and industrial research and engineering. This PYI has made significant contributions to his field of engineering and has potential to become a leader in academic research and education. The diary note describes the rigorous selection procedure. A grant award is highly recommended. Dr. Cioffi has obtained the maximum matching funds, so an award of $62500 is recommended.

A file server system for an Information Systems Laboratory will be provided for researchers at Stanford University in the Department of Electrical Engineering. This equipment is provided under the Instrumentation Grants for Research in Computer and Information Science and Engineering program. The research for which the equipment is to be used will be in the areas of optical processing, communication channels, signal quantization and compression, and related areas.

This project has three specific areas of study: Efficient Channel-Based Equalization, the computation of the equalizer via channel characterization derived from embedded training data; Interference Rejection for Code-Division Multiple Access, near-far and intersymbol interference and interference from disparate users; and Multicarrier Methods for Broadcast Transmission, for mitigation of time-varying fading effects. The focus of the study is on the time-varying multipath data channel. At relatively low data rates, the time-varying nature of wireless communication channels often leads to channel variation over a small number of symbol intervals. In this case a significant amount of training data can be embedded in the transmitted packets of data to enable adjustments to be made at the receiver. An alternative, perhaps forced by the need for higher data rates, is to increase the bandwidth of the transmitted signal. Then the relative rate of channel variation is less compared to the symbol rate, and the fraction of training is reduced. As wider bandwidths are used, multipath effects become more important and more sophisticated receiver structures need to be used. The research studies both narrow and wideband transmission, for applications in digital cellular radio and digital broadcast channels.

ITR: COLLABORATIVE RESEARCH: (EVS+NHS)-(int+dmc): 'FAST Copper': Dynamic Optimization of Resources in Frequency, Amplitude, Space, and Time for Broadband Access Networks

Mung Chiang, Princeton University
John Cioffi, Stanford University
Alexander Fraser, Fraser Research

Award 0427677

Abstract

Broadband access is the commercial and technical future of telecommunications. Higher data rates on access links enable any or all of video, data, and voice/audio signals. It is widely recognized that the ability to deploy ubiquitous, robust, broadband access services to the majority of U.S. households is vital to economic prosperity, a vibrant civil society, and homeland security. The goal of this 'FAST Copper' project is to help build an engineering foundation to bring broadband information services to everyone with a phone line, including people who live in rural and less-privileged areas. This can be achieved by substantially enhancing the rate and reliability of the existing copper plant access network. Equity of broadband information access in the U.S. will be enhanced as a result. There are two threads of research activities towards this goal: (a) dynamic and joint optimization of resources in Frequency, Amplitude, Space, and Time (FAST) to overcome the attenuation and crosstalk bottlenecks, and (b) integration of communication, networking, computation, modeling, and distributed information management in the multi-user environment of twisted pair networks. Innovations in both physical layer algorithms and network architectures and protocols are pursued. In particular, Dynamic Spectrum Management, a science of multi-user methods for adaptively tuning an access network to specific situations dynamically, is investigated for rate improvements and implementation viability. This proposal has major activities integrating research with education. It also facilitates close collaboration with industry in analyzing highly valuable empirical data and validating research results through extensive lab tests.