Cognitive Radio allows opportunistic spectrum access (OSA) of licensed frequency bands by unlicensed users so as to reduce spectrum scarcity led by the increasing market demands. Spectrum sensing is an essential mechanism for a cognitive radio system. Therefore attention should be given towards the security aspects of spectrum sensing in cognitive radio. This paper analyses the two protocols me...

In this chapter we shall consider security, immunity and adaptability aspects of Cognitive Radio (CR) networks and its applications. We shall cover design of a immunity/adaptability and security simulation model for cognitive radio and discuss results of conducted experiments using Matlab simulation tools and Crossbow’s XMesh using MoteWorks software platform. The aim of this chapter is to prov...

This paper addresses time-efficient broadcast scheduling problem in Cognitive Radio (CR) Networks. Cognitive Radio is a promising technology that enables the use of unused spectrum in an opportunistic manner. Because of the unique characteristics of CR technology, the broadcast scheduling problem in CR networks needs unique solutions. Even for single channel wireless networks, finding a minimum...

Cognitive radio (CR) is a new paradigm that utilizes the available spectrum band. The key characteristic of CR system is to sense the electromagnetic environment to adapt their operation and dynamically vary its radio operating parameters. The technique of dynamically accessing the unused spectrum band is known as Dynamic Spectrum Access (DSA). The dynamic spectrum access technology helps to mi...

Opportunistic use of White Spaces (WS) has opened up a whole new paradigm in research on cognitive radio (CR). One of the issues addressed by the QoSMOS project is the design of a flexible and efficient physical layer (PHY) for CR systems. To this aim, different modulation techniques are being investigated and are presented in this paper. They fulfil the low out of band leakage and spectral eff...

The increasing demand for wireless communication introduces efficient spectrum utilization challenge. To address this challenge, cognitive radio (CR) is emerged as the key technology; which enables opportunistic access to the spectrum. CR is a form of wireless communication in which a transceiver can intelligently detect which communication channels are in use and which are not, and instantly m...

It is well known that the successful operation of cognitive radio (CR) between CR transmitter and CR receiver (CR link) relies on reliable spectrum sensing. To network CRs requires more information from spectrum sensing beyond traditional techniques, executing at CR transmitter and further information regarding the spectrum availability at CR receiver. Redefining the spectrum sensing along with...

Spectrum overcrowding continues to present is a fundamental challenge for both military and commercial communications. Recent studies suggest that spectrum congestion is primarily due to inefficient usage rather than spectrum availability. Dynamic Spectrum Access (DSA) and Cognitive Radio (CR) are two techniques being considered to improve spectrum efficiency and utilization. Interest in Cognit...

Cognitive Radio (CR) significantly improve spectrum utilization through dynamic spectrum access (DSA). Efficient utilization of the unused or partially used spectrum for providing opportunistic access to secondary users (SU) is the main function of CR. CR has to sense continuously radio environment and keep on adjusting its transmission parameters for opportunistic transmission without causing ...

Cognitive Radio (CR) is a promising technology which deals with using vacant spectrum of licensed frequency band opportunistically. In CR Network, route construction must not affect the transmission of Primary User activity. In CR technology challenge of maintaining optimal routes arises due to PU activity and mobility of spectrum resources i.e. CR users. Maintaining optimal routes in Ad-hoc CR...