Cognitive radio is an emerging technology that enables the flexible development, construction, production, shipping, and deployment of highly adaptive radios that are built upon software defined radio technology. This contribution starts with a brief section that underlines the paramount importance of the mobile radio communications channel. Then, spectrum issues are discussed to emphasize the ...

Traditional distributed power control algorithms in cognitive radio networks are based on the assumption of perfect channel estimation which can lead to performance degradation in practical system. Cognitive radio sensor network (CRSN) has emerged as a promising solution to address the spectrum-related challenges of wireless sensor networks (WSN). Moreover, cognitive radio (CR) gives us a possi...

The efficient utilization of radio resources is a fundamental issue in cognitive radio (CR) networks. Thus, a novel cognitive radio resource management (RRM) is proposed to improve the spectrum utilization efficiency. An optimization framework for RRM is developed that makes the following contributions: (i) considering heterogeneous primary users (PUs) with multiple features stored in a radio e...

In this paper, we integrate overlay cognitive radio technology into 4G cellular networks for the sharing of TV spectrum. On one hand, OFDM is a promising technique for high-speed data transmission over multipath fading channels and has been considered to be the best candidate for 4G mobile networks. On another hand, the overlay cognitive radio model makes it possible to have two concurrent tran...

in cognitive radio (CR), CR users or also known as secondary users (SUs) are considered licensed spectrum. During the case when the primary user claims the band of the spectrum that is occupied by the SU ongoing call must be transferred to another unused spectrum band. The variation in spectrum band is called spectrum mobility. In this paper, we investigate an analytical model to show the effec...

With growing interest in using cognitive radio (CR) technology in wireless communication systems for vehicles, it is envisioned that future vehicles will be CR-enabled. This paper discusses CR technologies for vehicular networks aimed at improving vehicular communication efficiency. CR for vehicular networks has the potential of becoming a killer CR application in the future due to a huge consu...

Cognitive Radio (CR) can optimize system objects by dynamically assigning network resource and adjusting network operations in terms of network environments and conditions. So CR technology is very suitable for building emergency communication system to improve resource utilization ratio and enhancing dependability and availability of communication services apparently. In this paper, background...

Today wireless field is rapidly evolving. Due to the large number of standards, spectrum availability has become an important issue. In this context, an emerging technology, cognitive radio (CR) has been come out to solve this spectrum scarcity problem. The most important function of cognitive radio is spectrum sensing which requires more accuracy & low complexity. In this paper we analyze the ...

Increasing demands for high speed wireless access gave rise to new approach to radio communications and spectrum management – Cognitive Radio (CR). One of the key components of cognitive radio – dynamic spectrum access – shows a way to overcome the scarcity of one of the natural resources – radio frequency spectrum. The research in the domain of CR spans the wide area from information and signa...

The limited available spectrum and the inefficiency in the spectrum usage necessitate a new communication technology, referred to as cognitive radio (CR) networks. The key characteristic of CR system is that it senses the electromagnetic environment to adapt their operation and dynamically vary its radio operating parameters. A cognitive radio must detect the presence of primary user to avoid i...