Cognitive Radio Concept and Challenges in Dynamic Spectrum Access for the Future Generation Wireless Communication Systems

Abstract

Recently, the Dynamic Spectrum Access (DSA) techniques are proposed to solve the problem of spectrum scarcity and help to use the limited spectrum resource as effectively as possible. The current ongoing spectrum reform opens up the possibilities to exploit the DSA techniques. This paper aims to provide a critical review on the various ongoing efforts towards the use of DSA concept for the frequency management of future wireless communications systems, especially from the Cognitive Radio (CR) perspective. The CR aims for an efficient and dynamic access to the spectrum, and provides a new method of spectrum management. This paper also highlights the various challenges associated with CR in order to realize the concept of DSA.

Improvement of energy consumption in MIMO with cognitive radio networks

“…For an applied twin of comes and leaves time instants, an accurate formulation is derived from the conditional detection probability, then used to formulate the exact mean detection probability. Kumar et al [7], for randomly emerging or leaving signals, a sensing strategy is proposed. The proposed method first determines a test statistic for spectrum sensing based on the cyclostationarity approach to implement the strategy.…”

Antenna for Cognitive Radio Applications — A Review

“…Licensed spectrum: part of the electromagnetic spectrum assigned exclusively to wireless service providers for independent usage within a specific geographical area by paying the pre-decided license fee. Whereas unlicensed spectrum is for nonexclusive usage and can be used by anyone, but it is subject to some regulatory constraints [2]. The CR concept is mainly based on the paid spectrum for which a license is issued.…”

An Efficient Adaptive Technique with Low Complexity for Reducing PAPR in OFDM-Based Cognitive Radio

“…Recently, cognitive radio [2,3] has attracted much attention, as it can solve the spectrum scarcity problem [4] by allowing cognitive users (unlicensed users) to occupy the spectrum band when the primary users (licensed users) do not use their licensed spectrum. The main functions that a cognitive radio can perform are: spectrum sensing, spectrum management, spectrum mobility, and Spectrum Sharing [4]. From standards point of view, most of the cognitive radio-based standards have selected OFDM, or a variation of it, as their modulation scheme.…”