A HOS-Based Blind Spectrum Sensing in Noise Uncertainty

Abstract

Abstract. Spectrum sensing for cognitive radio is a challenging task since it has to be able to detect the primary signal at a low signal to noise ratio (SNR). At a low SNR, the variance of noise fluctuates due to noise uncertainty. Detection of the primary signal will be difficult especially for blind spectrum sensing methods that rely on the variance of noise for their threshold setting, such as energy detection. Instead of using the energy difference, we propose a spectrum sensing method based on the distribution difference. When the channel is occupied, the distribution of the received signal, which propagates under a wireless fading channel, will have a non-Gaussian distribution. This will be different from the Gaussian noise when the channel is vacant. Kurtosis, a higher order statistic (HOS) of the 4 th order, is used as normality test for the test statistic. We measured the detection rate of the proposed method by performing a simulation of the detection process. Our proposed method's performance proved superior in detecting a real digital TV signal in noise uncertainty.

Gaussianity Testing as an Effective Technique for Detecting Discontinuous Transmission in 5G Networks

“…If w(n) and s(n) are independent random variables, their sum is also Gaussian-distributed, with the mean being the sum of the two means, and the variance being the sum of the two variances, i.e., N µ w + µ s , σ 2 w + σ 2 s , which for clarity of description will be further indexed as N µ w+s , σ 2 w+s . Continuous transmission therefore precludes the use of goodness-of-fit tests, as these methods are based on the assumption that the distribution of mixed signal and noise is different from the sole distribution of noise [25]. In the case of intermittent transmission, however, the receiver collects not only signal-with-noise samples from N µ w+s , σ 2 w+s , but also a certain proportion of noise-only samples from N µ w , σ 2 w .…”

“…If p ≥ 0.5, then x belongs to the signal class. HOS-based detection using 4-th to 6-th order cumulants has become the recommended sensing method for DTV signals in the IEEE 802.22 standard [25].…”

“…Method described in [21], which uses a fundamentally different basis of detection, is a benchmark adopted in the conducted research. The research covers the most frequently referenced GoF tests, indicated as those with high efficiency and superiority to other similar, i.e., Jarque-Bera (JB) [22]- [24] and higher-order statistics (HoS) [25], [26].…”