A Two-Tiered Cognitive Radio System for Interference Identification in 2.4 GHz ISM Band

A detection module has been prototyped for cognitive radio usage in the industrial, scientific and medical (ISM) band using time domain as well as frequency domain detection. Duty cycle and pulse width characteristics are used for detection in the time domain. Fast Fourier transform (FFT) signatures and spectral occupancy information is used to confirm the detection in the frequency domain. The detection module is designed to behave dynamically. Varying the input parameters to the detector module adjusts the detection overhead. The overhead varies depending on the relative usage of a fast detection algorithm versus a slower but more accurate scheme; the number of device types to be detected; and whether frequency-selective scanning or wide-band detection is needed. The prototype is built on a software radio platform and is targeted for future software defined radios (SDR), and can be adapted to current and future orthogonal frequency division multiplexed (OFDM) systems.