Proliferation and innovation of wireless technologies require significant amounts of radio spectrum. Recent government policy reforms by the FCC are paving the way by freeing up spectrum for a new generation of frequency-agile wireless devices based on software defined radios (SDRs). Despite recent advances in experimental SDR platforms, further research into SDR MAC protocols or applications requires an experimental platform for managing physical spectrum access.

We have developed Papyrus, a software platform for wireless researchers to develop and experiment dynamic spectrum systems using currently available SDR hardware. Papyrus manages the complexities of spectrum access at the physical layer, exporting a clean, manageable abstraction to the MAC layer. Papyrus provides
two fundamental building blocks at the physical layer: flexible non-contiguous frequency access and robust usable frequency detection. Researchers can deploy and experiment new MAC protocols and applications on Papyrus, which is available on the USRP GNU Radios, but can be adapted to run on all current SDR platforms.

Using Papyrus, we have built a series of dynamic spectrum sharing systems, supporting demanding applications and handling heterogeneity among wireless devices. To start, we have developed
Jello, a distributed MAC overlay for high-bandwidth media streaming applications, using per-session OFDMA. Recently, we have also developed Ganache, an intelligent guardband configuration system that adaptively configure frequency guardbands to mitigate cross-band interference. Together, Jello and Ganache form a more complete system for dynamic spectrum sharing. We will also be presenting Ganache and demonstrating our system at MobiCom 2010. Come join us!

You can download the USRP GNU Radio implementation of Papyrus and Jello here. The following figure shows our demo at Infocom 2010. It includes 3 pairs of USRP GNU radio links, demonstrating fully decentralized spectrum sharing. We also use 1 USRP as the spectrum analyzer. Click here to watch our Demo video.