 spectrum holes and assign them to a non-licensed user in need, labeled the secondary user (SU). The SU can utilize DOI: 0.1201/9781003368311-8 5G Wireless Communication System in Healthcare Informatics Maximum Amplitudes Heavy Use Heavy Use Sparse Use Frequency (MHz) FIGURE 8.1 Power Spectrum of a typical communication system [2]. Power Spectrum in Use Frequency Dynamic Spectrum Access "Spectrum Hole" FIGURE 8.2 Illustration of Spectrum Holes [2]. that frequency band that otherwise PU keeps using its frequency. In summary, the CRN always gives priority to the PU over the SU, unless the spectrum is vacant [3]. There is a great interest in the development of an efficient spectrum-sensing method as it is the key process in any CRN. Various methods of spectrum sensing include energy-based detectors [4-9], which have low computational complexity and reasonably good performance. Thus, in this work, novel techniques for energy- detection (ED) based spectrum sensing methods are explored. 8.2 RELATED LITERATURE REVIEW There is an amount of work in the literature, focusing on the spectrum sensing solutions for CRN. For instance, D. Cabric has developed spectrum sensing in a Optimized Cognitive Radio Networks cross-layer design [10]. This work shows that among the three different detection methods proposed for spectrum sensing, the pilot detection method requires a min- imum amount of sensing time at the expense of the perfect synchronization require- ment. Moreover, it shows that the performance of the ED method is limited by the longest processing times the noise uncertainties. On the other hand, the ED methods are found to be better in a low signal-to-noise ratio (SNR) scenario [4-9]. The benefits of cooperation based spectrum sensing (CSS) in the CRN are illustrated in [11]. Specifically, it shows that cooperation within the same frequency band can reduce the detection time which in turn improves the overall processing time. Among the existing CSS schemes, the methods are broadly categorized into three fusion technique