Enrichment of Adaptive Threshold in Cognitive Radio

Abstract

Cognitive radio is the technology that helps overcome the problem of scarcity in a spectrum. It has its application in empowering a secondary user to gain entry into the spectrum. This admittance is because of detection of unoccupied part of the spectrum. It can boost up the spectrum utilization. The sensing technique utilizes the energy detection method, one of the many available. Being the simplest form, it checks the spectrum for empty slots by comparing the energy present with a predefined threshold. The result of this is not satisfactory under noisy conditions. To enrich the detection; the fixed threshold should be made differential i.e., adaptive or other kind of threshold should be employed. In this work with simulation results it has been proved that detection is better with adaptive threshold and further enhanced by the incorporation of multiple energy detectors. Key words: Cognitive radio, energy detection, adaptive threshold INTRODUCTIONWireless communication was one of a kind which brought about a revolution in the field of communication and with its advent came the surge of customers in wireless network services. The wireless spectrum has become a form of inevitable resource because of its limited availability. The reason for this is the escalation in demand of the radio spectrum. It brings constraints on the bandwidth, network generation and number of users. In reality the spectrum is not systematically allocated. It is regardless of the schemes which depict how the spectrum is assigned to the user. These schemes indicate that the spectrum has run out of capacity to accommodate any further user for communication purposes.The solution that jumps this hurdle in the less available spectrum is Cognitive Radio (CR). It is this technology that makes use of detecting scheme called a spectrum sensing characteristic. The major utilization lies in the fact that it grants access to a secondary user to occupy a part of the spectrum which is vacant at the moment. But the primary user still has more privilege than the secondary users. This phenomenon brings about the better allotment of the spectrum among the various users. This process of detection of unused spectrum contributes to the major principle of the cognitive radio. For the sensing process the primary system should remain undisturbed during allocation and usage of the spectrum by the secondary user and also spectrum holes (unused spectrum) should be identified efficiently. These contribute to the chief interests of the spectrum sensing (Furtado et al., 2015).For such a sensing process, there are a variety of detection procedures. Some of which are the transmitter detection processes such as matched filter detection, energy detection and the cyclostationary-feature detection. Energy detection is suitable for pragmatic applications. The