SAFIRE: Distributed Collaborative Spectrum Access

(Current members: Lili Cao, Lei Yang, Prof. Heather Zheng)
We are developing distributed algorithms and protocols to enable fair and efficient spectrum sharing among cognitive radios. Nodes apply local actions to tune network wide spectrum allocation. We have demonstrated the feasibility and performance-improvement at our recent papers in Crowncom 07, DySPAN 05, SECON 05.

Dynamic Spectrum Auctions: Systems and Algorithms  

(Current members: Lili Cao, Sorabh Gandhi, Xia Zhou, Prof. Subhash Suri, Prof. Heather Zheng)
We are working on applying short-term dynamic spectrum auctions to distribute spectrum based on dynamic user demand and willingness-to-pay. The challenge is how to derive auction results in real-time while addressing interference constraints. Our work in DySPAN 07 presented a fast auction clearing mechanism that can process 4000 requests in less than 2 minutes.

Proactive Spectrum Access

(Current members: Lei Yang, Lili Cao, Prof. Heather Zheng)
We are working on providing reliable spectrum access for secondary users in the presence of primary users.  We presented an alternative approach to traditional reactive spectrum access (sense and leave) approach. Proactive spectrum access allows nodes to predict future spectrum availability and schedule spectrum access and connectivity patterns to fully utilize rich yet dynamicall-available spectrum white-space. See our [apers in TAPAS 2006, and Crowncom 2007 for details.

Programmable Radio Testbeds using 802.11 WLAN devices 

(Current members: Lei Yang, Prof. Heather Zheng)
We are developping a reconfigurable wireless testbed using off-the-shelf 802.11 WLAN cards. We have modified Linux MadWiFi driver to support TDMA based MAC protocols with fast channel switch (<5ms delay).