Under the contemporary spectrum usage regulations, radio frequency bands are allocated statically to licensed users in a large geographical area and over a long period of time. Recent investigations revealed that such static spectrum allocation has led to very poor spectrum utilization. Cognitive radio has emerged as a new communication paradigm to improve spectrum utilization. It is defined as...

Cognitive Radio is an modern technology that is used to get the picture of spectrum and cope themselves to operate the secondary users who are unlicensed to share the spectrum with licensed primary users. Cooperative spectrum sensing allows unlicensed access whenever possible to the unexploited portions of the licensed spectrum by exploiting the spatial diversity among multiple secondary users....

Spectrum sensing is the basis of cognitive radio technology. Cooperative spectrum sensing has been shown to increase the reliability of spectrum sensing. To reduce sensing overhead and total energy consumption, it is recommended that the users with good performance should be selected to increase the sensing reliability. However, which of the cognitive users have the best detection performance i...

The spectrum is a scarce resource and must utilize efficiently, the cognitive radio is a prospective solution for underutilized spectrum. The spectrum sensing is a key functionality to alleviate interference of secondary user to primary. The cognitive radios must detect the existence of the primary user and vacate the band for the primary immediately if the primary user detected. In cooperative...

Almost 80 to 90 percent of the radio spectrum is left unutilized at any period of time, while at the same time some other regions of spectrum experience overcrowding. We consider a dynamic spectrum access system in which Secondary Users (SUs) choose to either acquire dedicated spectrum or to use spectrum-holes (white spaces) which belong to Primary Users (PUs). The tradeoff incorporated in this...

Spectrum sensing is indispensable for cognitive radio to identify the available white spaces. Energy detection is considered as a preferred technique for spectrum sensing in cognitive radio networks. It is because of its simplicity, applicability and low computational complexity, energy detection is employed widely for spectrum sensing. This paper proposes an enhanced energy detection based spe...

Cognitive radio allows unlicensed users to access licensed frequency bands through dynamic spectrum access so as to reduce spectrum scarcity. This requires intelligent spectrum sensing techniques. This paper investigates the use of cyclo-stationary detector and performance evaluation for Digital Video Broadcast-Terrestrial (DVB-T) signals. Generally, DVB-T is specified in IEEE 802.22 standard i...

Cognitive radio is an intelligent communication system which focus on dynamic spectrum usage rather than fixed spectrum assignment. Cooperative spectrum sensing is a technique for detecting the primary user accurately based on information collected from various secondary users. Energy detection technique for spectrum sensing method is employed to determine the occupancy of the frequency spectru...

Cognitive radio (CR) is an emerging technology that enables the flexible development and deployment of highly adaptive radios that are built upon software defined radio technology. These types of networks have applications in dynamic spectrum access, co-existence of different wireless network, interference management, etc. They are touted to drive the next generation of devices, protocol and ap...

Vehicular Ad hoc NETworks (VANETs) as the basic infrastructure can facilitate applications and services of connected vehicles (CVs). Cognitive radio (CR) technology is an effective supplement and enhancement for VANETs. It can reduce the impact of deficiency of spectrum resource in VANETs. Although CR-VANETs can utilize the unused licensed spectrum effectively, the distributed nature of CR-VANE...