Self Organization Approaches for Optimization in Cognitive Radio Networks
In order to deliver growing data rates at an ever decreasing cost per bit in modern communication networks, the spectral efficiency must be further improved . However, the current static spectrum allocation policy, Self Organization Approaches for Optimization in Cognitive Radio Networks in which governmental agencies assign spectrum to license users on a long-term basis for large geographical regions, faces spectrum scarcity in particular spectrum bands and cannot satisfy the increase in spectrum demand. Furthermore, Self Organization Approaches for Optimization in Cognitive Radio Networks because of a large portion of the assigned spectrum being used sporadically, a significant amount of spectrum is under-utilized. Hence, a new communication paradigm,
whose key enabling technology is referred to as Cognitive Radio CR , Self Organization Approaches for Optimization in Cognitive Radio Networks was recently proposed to solve these spectrum inefficiency problems. Each CR user of cognitive radio networks CRNs may adapt its transmission parameters to the changes of wireless environment so as to efficiently exploit the available spectrum. Self Organization Approaches for Optimization in Cognitive Radio Networks Since the CR technology enables the unlicensed users to share the spectrum with the primary licensed users in an opportunistic manner, both the spectrum utilization and the coverage area can beognitive radio CR is regarded as a promising technology for providing a high spectral efficiency to mobile users by using heterogeneous wireless network architectures and dynamic spectrum access techniques. However, Self Organization Approaches for Optimization in Cognitive Radio Networks cognitive radio networks CRNs may also impose some challenges due to the ever increasing complexity of network architecture, the increasing complexity with configuration and management of large-scale networks, fluctuating nature of the available spectrum, diverse Quality-of-Service QoS requirements of various applications, Self Organization
Self Organization Approaches for Optimization in Cognitive Radio Network
Approaches for Optimization in Cognitive Radio Networks and the intensifying difficulties of centralized control, etc. Spectrum management functions with self-organization features can be used to address these challenges and realize this new network paradigm. In this paper, fundamentals of CR, including spectrum sensi n g , Self Organization Approaches for Optimization in Cognitive Radio Networks spectrum management, spectrum mobility and spectrum sharing, have been surveyed, with their paradigms of self-organization being emphasized. Variant aspects of selforganization paradigms in CRNs, including critical functionalities of Media Access Control MAC and network-layer operations, are surveyed and compared. Furthermore, new directions and open problems in CRNs are also identified in this survey.
ognitive radio, self-organized networking, heterogeneous, machine-to- considerably improved. However, DSA technology suffers from low scalability and convergence. Moreover, CRNs may also impose new challenges due to the ever increasing complexity of network architecture, fluctuating nature of the available spectrum and some other important issues that impact the Quality-of-Service QoS of user applications. Furthermore, some challenges willfurther appear in the future heterogeneous networks. In order to address the aforementioned challenges, decentralized approaches can be adopted, leading to a new paradigm, i.e., selforganization. Since self-organization is regarded as a promising solution for largescale networks, enormous researches have been carried out to address the challenges brought by the ever increasing complexity, heterogeneity, and dynamics in complex communications systems. Besides Mobile Ad-hoc NETworks MANETs and Wireless Sensor Network WSNs , the self-organization properties have also been investigated in wireless cellular standards with an ultimate goal of improving the robustness, reliability, scalability and power efficiency of the networks. Furthermore, in CRNs, mechanisms of self-organization have also been emphasized to address the problem of spectrum scarcity . It has been well recognized that some sophisticated approaches could significantly reduce the information exchange between coordinated users. Therefore, DSA can acquire significant benefits from th self-organization features such as distributed.