Advanced Spectrum Sensing Techniques

Limitations In Narrow Band Sensing

Time consumption involved in sensing is considered as one of the major limitation of Narrowband sensing. It limits the local observations which lead to incomplete sensing information. The traditional narrowband spectrum sensing techniques are Matched filtering, energy detection, Cyclostationary detector and covariance based detector (Sun, Nallanathan, Wang, & Chen, 2013). Matched filtering technique (Jaiswal, Kumar Sharma & Singh, 2013) correlates the known reference signal with the received signal to detect the presence of Primary User (PU). However, it requires prior knowledge of PU signal and need to maintain synchronisation. In energy detection technique (Digham, Alouini, & Simon, 2007), the received signal energy is compared with a threshold to detect the presence of PU. When compared to the previous technique it does not require any prior information about PU. However due to the stochastic nature of wireless channel, it is cumbersome to differentiate PU from CR user. Cyclostationary detector (Sutton, Lotze, Nolan, & Doyle, 2007) utilizes the cyclic correlation property of modulated signals. It performs well in low SNR regions. It consumes more time for spectrum sensing and it is computationally complex. In covariance based detector (Zeng & Liang, 2009), covariance matrix of the received signal is used to detect the signals. It utilizes the dispersive nature of channels. It is also affected by noise uncertainty.