Broadband local Access
Instructor: Paul S. Henry
VENUE: LC102 DATE: MAY 30, 2007. 9:00 AM TO 12:30 PM
Local access, variously called the ‘last mile’, ‘first mile’ and just plain ‘bottleneck', represents formidable challenges to the communications engineer. Especially in the broadband arena, the twin objectives of high performance and very low (consumer-level) cost are especially daunting. There has been no shortage of proposed solutions to this problem, with wire, wireless and fiber technologies all represented. While fiber is often considered to be the ‘ultimate’ solution, it has not displaced the alternatives, and likely will not any time soon. For the foreseeable future we will be dealing with a range of access technologies, optimizing each for particular applications and attempting to make rational choices among them.
This tutorial is an introduction to the major broadband access technologies: digital subscriber loop, cable, fiber, WiMAX, cellular and powerline. In addition to presenting a survey of these options, the tutorial will look beneath their obvious superficial differences and identify the common themes -- the underlying engineering principles -- upon which they all depend. Application of these principles to a particular wired or wireless medium, with its own unique set of characteristics and limitations, yields an access solution with specific strengths and weaknesses, which will be discussed. Elementary models for various access approaches will be developed to provide insight into their performance characteristics as well as the cost considerations associated with their deployment. Throughout the discussion, the performance predicted by these models will be compared with results achieved by actual equipment in real-world implementations.
Paul S. Henry is a Member of the Access Technology & Applications Research Division at AT&T Labs, where his interests focus on bringing high-speed Internet connectivity to homes and businesses. After receiving his Ph.D. in physics from Princeton University, Mr. Henry joined AT&T (Bell) Laboratories, where he has been engaged in research on communications circuits and systems as well as radio astronomy instrumentation. He served as a Technical Editor of IEEE Communications Magazine, a Guest Editor for the Journal of Lightwave Technology and has published papers or patented inventions in several fields, including millimeter-wave radio techniques, cosmology, optical fiber and powerline communications, wireless systems and data security. Dr. Henry's current research emphasis is on broadband wireless access technology. He is a Fellow of the IEEE and was the keynote speaker at Infocom 2002 (New York) and ICCCP’05 (Muscat, Oman).