Spectrum sensing using adaptive threshold based energy detection for OFDM signals

Spectrum sensing is one of the key technologies to realize dynamic spectrum access in cognitive radio systems, especially for the next generation mobile systems. In this paper, the OFDM signal is sensed using a wide-band cognitive radio system. A new adaptive threshold algorithm is proposed for the Discrete Wavelet Packet Transform (DWPT) and Welch´s energy detection methods to illustrate the trade-off between detection probability and false alarm probability. The proposed adaptive threshold algorithm in both DWPT and Welch´s method demonstrates that the target performance requirements for the sensing algorithm equation for today can be achieved at -18dB, that is a very low signal level for sensing.