Models for Analyzing Cognitive Radio Interference to Wireless Microphones in TV Bands

TV bands are candidates for unlicensed spectrum access based on cognitive radio (CR) devices. However, for a successful dynamic spectrum access regime in TV bands, any new unlicensed devices need to ensure that they do not interfere with the incumbent devices such as TV receivers and wireless micro phones in these bands. This paper presents models for carrying out interference analysis of CR devices to wireless microphones. The wireless microphone systems are more susceptible to interference by CR devices compared to TV receivers due to their lower power and use of randomly selected idle TV bands at a given location. We present two models for interference, a single interferer model that determines the unlicensed device characteristics needed to protect a wireless microphone system from interference, and a multiple interferers model that provides a measure of the maximum density of unlicensed devices that can operate in a given region without affecting wireless microphone systems. We further analyze the benefits of cooperative sensing among CR devices using the multiple interferers model. Lastly, we provide recommendations for reducing interference based on the two interference models.