Wireless Interdisciplinary Research Group

Welcome to WIRG!


 

The Wireless Interdisciplinary Research Group (WIRG) is a research group located in the Computer Science Department at the University of Colorado Boulder.

The WIRG views improving radio frequency (RF) spectrum availability as a crucial challenge to address. Spectrum availability for wireless internet access (cellular, Wi-Fi, etc.), for weather observing via Earth Observing Satellites (EOS), for Radio Astronomy scientific observations investigating the formation of the Universe, and for aircraft and military operations truly pervade every aspect of daily life. Our research focus is on the intersection of wireless communications, passive and active spectrum sharing, spectrum policy, and hardware security in support of secure spectrum sharing for communications and scientific purposes. Several of the lab’s ongoing projects are supported by the National Science Foundation and by NASA.

Radio frequency (RF) spectrum has become a scarce resource. Currently, there are more connected devices on Earth than there are people, and the trend is for these devices to connect via a wireless first hop. Some analysts forecast that as many as 95% of internet-connected devices will be wireless. The National Institute of Standards and Technology (NIST), the Federal Communications Commission (FCC), and the National Telecommunications Industry Association have widely publicized the developing “spectrum crunch.”

In 2010, President Obama directed NTIA, in collaboration with the FCC, to make available 500 MHz of Federal and nonfederal spectrum for wireless broadband use. The process is still ongoing, however, for the most part the RF spectrum has already been allocated, forcing existing services to share their allocation with other wireless application services. The days of exclusive spectrum allocations are gone, and the age of spectrum sharing is becoming the new normal.

Most spectrum sharing mechanisms enable sharing of RF spectrum between systems that actively transmit, or active systems, by sensing transmissions and either waiting to transmit, or moving to a different frequency. Passive systems such as radio astronomy telescopes and earth observing satellites, on the other hand, do not transmit when they are operating, so an active system looking for spectrum has no way of telling that a frequency band is being used by a passive system. Protection for such systems is required and has been afforded through the mechanism of radio quiet zones (RQZs), which are geographic areas within which transmissions are restricted. RQZs, while effective, do not make effective use of spectrum, since spectrum is unused, even when RA facilities are not making observations. 

A new concept in the RF spectrum world is the Radio Dynamic Zone (RDZ). An RDZ is effectively the opposite of an RQZ. RQZs limit transmissions from systems inside and around the zone to protect sensitive receivers inside the zone from interference. In contrast, an RDZ protects receivers outside the zone from transmitters inside the zone, some of which could potentially be very high power – powerful enough to cause damage. The protected area of an RDZ varies with the power of the transmitting system. Protection is only needed when systems inside the RDZ are transmitting, and the spectrum is usable by systems outside the zone otherwise.

The primary problem to address is maximizing the effective utilization of the RF spectrum through secure spectrum sharing, while enabling co-existence of passive and active systems. The mechanisms analyzed should further be developed for their applicability to the definition and operation of RDZs.

This work is supported by the NSF and by NASA:

  • NSF Passive and Active Spectrum Sharing (PASS), NSF award #2030233

  • NSF Hat Creek Radio Observatory National Radio Dynamic Zone (HCRO-NRDZ), NSF award #2139964

  • NSF SII-NRDZ: Radio Astronomy Dynamic Satellite Interference-Mitigation and Spectrum Sharing (RADYSIS), NSF award #2232368

  • NASA Lunar Surface Exploration Communications Testbed (ExWC)

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