The TV white spaces offer an exciting opportunity for increasing spectrum availability by reusing spectrum not in active use by TVs and wireless mics. While it is simpler to detect TV transmissions, either using sensing or through the whitespace database, the detection of wireless mics is particularly challenging. Their use is dynamic and, furthermore, mic receivers are receive-only devices. For this reason the FCC has made very conservative rules that require white space devices (WSDs) to vacate any TV channel that is in use by a mic. We have been investigating this coexistence problem for over two years. Through a unique setup involving a faraday cage, an anechoic chamber, and white space devices, we characterize the impact of transmissions from WSDs on the audio recording of a wireless mic. We also present SEISMIC, a system that enables WSDs and mics to operate on the same TV channel with zero audible mic interference.
Joint work with George Nychis, Thomas Moscibroda, and Ivan Tashev.