SDI Seminar

Speaker: Tom Truman, University of California, Berkeley

InfoPad: A Platform for Exploring Protocol Design for Indoor Wireless Networks

Date: October 31, 1996

Abstract: The time-varying nature of the wireless channel presents a particularly challenging environment for supporting mobile, remote wireless access to multimedia services. High error rates, limited link bandwidth, and a diverse mixture of delay- and loss-sensitive data require link-level protocols which are able to adapt to current channel conditions to bring the mobile user the highest quality of service possible.

To gain insight about the real-time behavior of the indoor wireless link, the InfoPad system, a complete research infrastructure for wireless multimedia access, was built and has been used as a tool for gathering channel measurements of an in-vivo system. Equipped with a both a 1 Mbps frequency-hopping link to the backbone network, the InfoPad has been used to capture signal quality measurements at the receiver with a time resolution of 50 microseconds, as well as a second set of measurements which captured bit-error traces along with the signal at a 5 millisecond resolution. These measurements are then analyzed offline to provide insight about the dynamic behavior of the wireless channel.

In this talk, I will present an overview of the InfoPad system, focusing on the design and implementation of the InfoPad portable terminal and on the design of the wireless link subsystem. I will also discuss the measurement strategy, preliminary results, and the open issues in the analysis of the measurements and the application of the results to link-level protocol design.