Cognitive radio

Abstract:- In the wireless communication, the radio spectrum is allocated to multiple users . But the spectrum occupied by the various wireless applications is not distributed in a uniform manner. Some part of spectrum is rarely used while other is used extensively leading to unbalanced usage of frequency spectrum. So the cognitive radio technology is used to make maximum utilization of available licensed bandwidth. It is the one of the solutions to solve the spectrum scarcity problem and supports

Efficient resource allocation in cognitive radio networks considering time varying constraints Abstract: Wide spread acceptance of wireless technologies has given rise to increase in demand for bandwidth .cognitive radio was developed as a promising technique to overcome the scarcity of spectrum resources in wireless communication. The term cognitive radio is defined as an intelligent radio that can be programmed and configured dynamically. Particular portion of the spectrum can be used only by

The increased demand for radio spectrum has resulted from the evolution of feature-rich and high-data-rate wireless applications. The spectrum is limited, and the current radio spectrum regulations make its use less productive. This has necessitated the development of dynamic spectrum allocation policies to make the utilization of the existing spectrum in a better way. As per the current spectrum allocation regulations, specific bands are assigned to particular services and only licensed users are

Game-Theoretic Approach to Detect Selfish Attacker in Cognitive Radio Ad-Hoc Networks Abstract— In wireless communication, spectrum resources are utilized by authorities in particular fields. Most of the elements in spectrum are idle. Cognitive radio is a promising technique for allocating the idle spectrum into unlicensed users. Security shortage is a major challenging issue in cognitive radio ad-hoc networks (CRAHNs) that makes performance degradation on spectrum sensing and sharing. A selfish

In this global world of technologies where the communication is being modern day by day, on every other day the new technologies are being invented so in this vast world of growing technologies the cognitive radio network is another addition and a step toward fast and secure communication. Cognitive radio network is the network used for wireless communication which uses the spectrum of frequencies. It is an intelligent network in a sense that it can recognize the channels in use or vacant, the ability

wired medium known as channel. The transmitter transmits the information and the receiver receives the information. Information is useful data send by transmitter and must be understood to the receiver. The information is transmitted in the form of radio waves. This useful information is known as signal. Signal is the electric or electronic variation in voltage with respect to time. While dealing with communications with the two hardware required, transmitter and receiver • The input signal may beanalog

phone and listening to radio broadcast on driving performance will be explored. There are many careless drivers on the road who are mostly talking on the hand-held cell phone. It is predicted that using a hand-held phone would take the driver’s attention away and would cause driving slowly. Since many accident reports show that cell phone use while driving is dangerous it is questionable if listening to radio will also be detrimental on driving task. Many people turn on the radio for entertainment or

of radiation from cell phones and cell phone towers. In recent years, various studies have been conducted to determine whether the radio frequency waves from cell phone towers have a detrimental effect on health. Current research has yielded inconsistent results regarding the effects of radio frequency waves, and while the World Health Organization does not view radio frequency waves as serious risk, more research needs to be done in order to be certain (USDA, 2009). In this paper I will be addressing

necessary to think in terms of three distinct domains; the physical domain consisting of the natural environment in which the senses are dominant, the information domain consisting of data, information systems, and documented knowledge, and the cognitive domain which consists of situational awareness, assessment and understanding. Technological innovation introduced over time has provided the ability to transition from one

ORTHOGONAL FREQUANCY DIVISION MULTIPLEXING techniques allow the transmission of high data rates over broadband radio channels subject to multipath fading without the need for powerful channel equalization. However it is very sensitive to nonlinear effects due to the high PEAK TO AVERAGE POWER RATIO owned by their transmitted signals. Slimane Ben Slimane (2007) proposed an efficient technique for reducing the PEAK TO AVERAGE POWER RATIO of ORTHOGONAL FREQUANCY DIVISION MULTIPLEXING signals. The