Spectrum Sensing for Wireless Microphone Signals

Spectrum sensing in the context of wireless microphone (WM) signals is considered in this paper. The spectrum sensing algorithm developed in this study makes use of the property that the bandwidth of the WM signal is narrow compared with the bandwidth of a digital television (DTV) channel. As a result, the power of the WM signal is highly concentrated in the frequency domain and there are apparent peaks contained in the power spectrum density (PSD) of the WM signal even when the signal-to-noise power ratio (SNR) is as low as -20 dB. Based on this property, a simple spectrum sensing algorithm for the WM signal is evaluated using the maximum peak of the estimated PSD as the decision statistic. The probability of false alarm (P_FA) for the proposed WM detector is analytically derived. The operating characteristic curves for the spectrum sensing algorithm is determined from computer simulations. Simulation results show that the proposed spectrum sensing algorithm can easily achieve a probability of misdetection (P_MD) of 0.1 corresponding to a P_FA of 0.01 when the SNR is less than -20 dB and the sensing time equals 10 ms.