| Speaker: | Dr. Haitao Zheng, University of California-Santa Barbara |
|---|---|
| Abstract: | A variety of wireless devices are becoming increasingly ubiquitous, placing additional stress on the fixed radio spectrum available to all access technologies. Current fixed spectrum allocation results in very poor utilization of pectrum. To reuse "wasted" spectrum, the recent proposal on Open Spectrum systems allows unlicensed (secondary) users to sense the presence of legacy licensed spectrum holders (primary users) and opportunistically utilize unused licensed spectrum on a non-interfering basis. This "creates" new capacity and commercial value from existing underutilized spectrum. While it shows promise, the technology underlying open spectrum systems is still in its infancy. Issues in wireless communications and networking, once addressed in the context of fixed spectrum assignment, offer new research challenges in the realm of open spectrum systems. In this talk, we describe some initial studies on spectrum management of open spectrum systems. We begin by describing spectrum heterogeneity, a result of the dual-user nature of these systems that drastically complicates spectrum management. We then present a set of algorithms that allow fair spectrum access through the usage of network enforced rules. Specifically, we introduce both a centralized graph coloring approach that optimizes spectrum allocation for a static topology and a distributed approach where devices use local bargaining to adapt optimize spectrum assignment over topology variations. Next, we discuss the problem of device coordination in the absence of a predefined, commonly available spectrum slice for control traffic, and present our solution, a distributed coordination framework where devices dynamically select coordination spectrum slices based on local conditions. We conclude by summarizing this work in context, and discussing future directions in combining these results with higher layer mechanisms to produce an end-to-end programmable and adaptive network. |
| Biography: | Haitao (Heather) Zheng received her B.S.degree (with highest honor) from Xian Jiaotong University in July 1995, her M.S.EE and Ph.D degree in Electrical and Computer Engineering from University of Maryland, College Park, in May 1998 and July 1999, respectively. She joined wireless research lab, Bell-Labs, Lucent Technologies as a member of technical staff in August 1999, and moved to Microsoft Research Asia as a project lead and researcher, in March 2004. Since Sept. 2005, she has been an assistant professor in Computer Science Department, Univ. of California, Santa Barbara. Dr. Zheng was recently named as the 2005 MIT Technology Review Top 35 Innovators under the age of 35 for her work on cognitive radios. She received 2002 Bell Laboratories President's Gold Award from Lucent Bell-Labs, and 1998-1999 George Harhalakis Outstanding Graduate Student Award from Institute of System Research, University of Maryland, College Park. Dr. Zheng was admitted to the highly gifted class of Xi'an Jiaotong University, P.R. China at age of 15, and graduated with the highest honor. She has served as guest editors of JSAC and EURASIP special issues and TPC members of many conferences. Dr. Zheng's research area includes wireless communications and networking and multimedia computing. |
| Presented On: | Tuesday, November 8, 2005 |
| Videotape: | Zheng.mov |
