Self-organization paradigms and optimization approaches for cognitive radio technologies: a survey

Cognitive radio is regarded as a promising technology to provide high bandwidth to mobile users via heterogeneous wireless network architectures and dynamic spectrum access techniques. However, cognitive radio networks may also impose some challenges due to various factors such as the ever increasing complexity of network architecture, the high cost of configuring and managing large-scale networks, the fluctuating nature of the available spectrum, diverse QoS requirements of various applications, and the intensifying difficulties of centralized control. A plethora of work has been carried out to address the challenges aforementioned by employing cognitive radio functionalities with self-organization features. In this article, variant aspects of self-organization paradigms in cognitive radio networks, including critical functionalities of MAC- and network-layer operations, are surveyed. The main contributions of this survey include introducing the fundamentals of existing cognitive radio and self-organization techniques as well as their current progress, surveying critical cognitive radio issues (including common control channel management, cooperative spectrum sensing, bioinspired spectrum sharing, network scalability and adaptive routing) as well as their self-organization features, and identifying new directions and open problems in cognitive radio networks.