A Quick Overview of Different Spectrum Sensing Techniques

Background

To select effective sensing method for QoS in cognitive radio (Giweli, Shahrestani, & Cheung, 2016) had discussed, examine various non cooperative sensing methods precisely, and compare them with each other. Further, focused to identify the factors, which are essential to enhance the performance of CR system. In their study, they had also highlighted the requirement of real-time selection mechanism of the proper sensing method.

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  Limitations: Although the author factually describe the selection of sensing method for improving the Qos in Cognitive radio network (CRN) but simultaneously it has been observed that, in their study cooperative sensing techniques and their issues were not addressed. Secondly, Test statics of different non-cooperative sensing methods and current existing challenges in sensing techniques have not been discussed.

A comparative study of spectrum sensing Techniques in Cognitive Radio Networks (Khan & Nakagawa, 2013), have discussed different sensing techniques to verify the presence of primary user (PU) and had concluded that, more than 99% accurate decision related to the presence and absence of PU should be there in order to achieve effective spectrum sensing. Their study also revealed the appropriate sensing technique adoption for densely populated and for less populated licensed spectrum band.

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  Limitations: During the study authors didn’t explain the spectrum sensing framework and issues of cooperative spectrum sensing techniques. Eigen value Based Detection which is capable to maintain minimal probability of false alarm is not discussed, neither Covariance Based Detection nor Waveform Based techniques were considered. The present issues related to sensing techniques like Rate -Reliability adjustment, Multipath fading and Hidden Terminal Problem were also missing.

Spectrum Sensing in Cognitive Radio Networks: Requirements, Challenges and Design Trade-offs (Ghasemi & Sousa, 2008) the authors addressed a range of issues related to the design of spectrum sensing functionality for dynamic spectrum access. Most of the time author aimed towards the implementation, sensing challenges like (channel uncertainty, noise uncertainty aggregate-interference uncertainty) and regulatory challenges like (sensing periodicity, detection sensitivity), of spectrum sensing in cognitive radio system. In their study they investigate that how these issues are controlled by user-level cooperation, system-level coordination among the cognitive radios and different cognitive radio networks respectively.