The unlicensed spectrum is overcrowded with a large number of wireless devices -- Wi-Fi laptops, Bluetooth headsets, baby monitors, cordless phones, and many others. To achieve the best performance of wireless networks in this setting, it is necessary to make the wireless networks "spectrum aware". They should operate in the cleanest frequency spectrum. Furthermore, the network should operate on as much of the spectrum that is available. Hence they should not only adapt the channel number (center frequency) but also the channel width. We are exploring the design of such networks as part of the SPAWN project.

We are currently organizing the MSR Cognitive Wireless Networking Summit in Snoqualmie, WA. More information can be found here.

We are currently working on three sub-projects that together constitute SPAWN.

		CogWiFi: We are rethinking the design of Wi-Fi networks. For example, why is it necessary to impose "channelization"? Why not just give us the entire unlicensed spectrum and let the software dynamically determine how much spectrum to use at any given point. A simple question like this opens up the entire design space - from managing infrastructure networks to routing packets in a ad hoc network. As a key step towards this goal, we have built a system (using commodity hardware) that can adaptively change the channel width based on the node's demand.
		KNOWS (Cognitive Networking Over White Spaces): The goal of the KNOWS project is to enhance the state of the art by demonstrating a working cognitive radio prototype that looks for "white spaces" by sensing the TV spectrum; dynamically switches to an available white space, and operates in it without hurting incumbent TV receivers. Efficient communication in white spaces is enabled by CMAC and b-SMART, the new spectrum-aware medium access protocol used by our prototype. More detailed information is here.
		SPAWN-MATH: In the SPAWN-MATH project, we focus on Models, Algorithms, and THeory (MATH). Our goal is to model and analyze spectrum-aware wireless systems and thereby lay a thorough theoretical foundations for the entire SPAWN project. For instance, we are devising new models for spectrum-aware wireless systems with adaptive channel width. Based on these models, we develop distributed algorithms and protocols to best address the new challenges faced in such networks.

SPAWN is a project by the Networking Research Group.

Project Lead:

• Paramvir Bahl
• Ranveer Chandra
• Thomas Moscibroda

Collaborators:
We are actively collaborating with members of the Networking Research Group, the Communications and Collaboration Systems Group, the Distributed Systems & Security Research Group, the Wireless Incubation Group, and the Windows PC Ecosystem Technologies Group.

• Load-Aware Spectrum Distribution in Wireless LANs
  Thomas Moscibroda, Ranveer Chandra, Yunnan Wu, Sudipta Sengupta, Paramvir Bahl, Yuan Yuan
  IEEE ICNP , Orlando, FL (October 19-22, 2008)



• A Case for Adapting Channel Width in Wireless Networks
  Ranveer Chandra, Ratul Mahajan, Thomas Moscibroda, Ramja Raghavendra, Paramvir Bahl.
  ACM SIGCOMM , Seattle, WA (August 17-22, 2008)



• A Hardware Platform for Utilizing the TV Bands with a Wi-Fi Radio
  Srihari Narlanka, Ranveer Chandra, Paramvir Bahl, John Ian Ferrell.
  IEEE LANMAN, Princeton, NJ (June 10-13, 2007)



• Allocating Dynamic Time-Spectrum Blocks in Cognitive Radio Networks
  Yuan Yuan, Paramvir Bahl, Ranveer Chandra, Thomas Moscibroda, Srihari Narlanka, Yunnan Wu.
  ACM MobiHoc, Montreal, Canada (September 9-14, 2007)



• KNOWS: Kognitiv Networking Over White Spaces
  Yuan Yuan, Paramvir Bahl, Ranveer Chandra, Philip A. Chou, John Ian Ferrell, Thomas Moscibroda, Srihari Narlanka, Yunnan Wu.
  IEEE DySPAN, Dublin, Ireland (April 17-20, 2007)



• Towards an Architecture for Efficient Spectrum Slicing
  Vladimir Brik, A. Mishra, Suman Banerjee, Paramvir Bahl
  HotMobile 2007, Tucson, Arizona, (February 2007) (pdf, 644 Kbytes)



• Protocol Design Beyond Graph-Based Models
  Thomas Moscibroda, Roger Wattenhofer, Yvew Weber
  HotNets 2006, Irvine, California, USA, (November 2006)



• DSAP: A Protocol for Coordinated Spectrum Access
  Vladimir Brik, Eric Rozner, Suman Banerjee, Paramvir Bahl
  IEEE DySPAN 2005, Baltimore, MD (November 2005) (pdf, 146 Kbytes)

• Liz Tay, ITWorld Australia, 'Cognitive radios' to improve wireless devices, September 16, 2008
• Marie Boran, Silicon Republic, Microsoft develops smart wireless networks, August 19, 2008
• Rob Knies, Microsoft Research, Tweaking Channel Widths to Improve Wireless Communication, August 19, 2008
• Briony Smith, ITWorld Canada, Microsoft Research hits the road with mobile tech, March 11, 2008
• Nancy Gohring, PCWorld, Inside Microsoft Research: The Cutting Edge on Display, March 4, 2008
• Information Week, Microsoft Preps Cognitive Radio Prototype For Use With TV Spectrum by Thomas Clayburn, February 12, 2007