“…Energy detection is a blind detection algorithm; however, noise variance must be estimated firstly [5][6][7]. Other detection algorithms, for example, cyclostationarity feature detection [8][9][10], covariance-based absolute value detection [11], eigenvalue detection [12,13], autocorrelation-based detection [14], energy-autocorrelationbased detection [15] etc., have been presented in the published literatures. However some channel parameters of above-mentioned algorithms, for example, channel gain, signal-to-noise ratio (SNR) and noise variance, must be estimated before the algorithms can be applied.…”