2008 Research Summary

Collaborative Communication for Cognitive Radio Applications

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Ben Juda Wild and Kannan Ramchandran

It is well known that wireless spectrum is vastly under-utilized. In our previous work, we attempted to re-use spectrum by dynamically sensing receivers, and re-using bands where no receivers were tuned to [1]. Currently, our focus has shifted to using collaborative beamforming among cognitive radios to use the spatial dimension efficiently [2]. In [2] we describe the world's first experimental distributed beamforming testbed. Using this testbed, we have shown that N collaborating radios can in fact achieve beamforming gains proportional to N².

[1]

B. Wild and K. Ramchandran, "Detecting Primary Receivers for Cognitive Radio Applications," Proc. Dynamic Spectrum Access Networks, November 2005.

[2]

R. Mudumbai, B. Wild, U. Madhow, and K. Ramchandran, "Distributed Beamforming Using 1 Bit Feedback: from Concept to Realization," Proc. Allerton Conf. Communication, Control and Computing, September 2006.