A Survey on Dynamic Spectrum Access via Cognitive Radio: Taxonomy, Requirements, and Benefits

Conventionally, interference protection among radio spectrum users is guaranteed through a policy of spectrum licensing that provides exclusive access to licensed users. However, as it is becoming extremely difficult to satisfy the growing demand for radio spectrum with this conventional policy, a flexible policy that can improve radio spectrum access and utilization without causing interference amongst users has recently gained increasing interest. In this context, this paper presents a comprehensive survey on flexible radio spectrum management with full focus on a cognitive radio technology application for dynamic spectrum access. The study approach involves analytical evaluation of the performance of the current fixed radio spectrum allocation policy examining both technical and economic perspectives. The result of which shows that the current fixed radio spectrum management policy is too rigid, inefficient and out-dated and needed to be replaced with a flexible radio spectrum management policy. Based on this analytical result, an in-depth survey on innovative technology and standards for a dynamic spectrum management model that can enhance an increase in spectral utilization and coexistence of multiple radios with adequate interference free communication was carried out. The paper also discusses the interrelationship between technologies, business and policies for cognitive radio standardization for seamless wireless communication. In addition, the paper presents both the technical and economic benefits of the dynamic radio spectrum management model over the current fixed radio spectrum allocation policy. The paper was finally concluded recommending the commercial adoption of dynamic spectrum access worldwide keeping in mind all the benefits of the dynamic spectrum access model and standards in place to ensure interference free communication in a cognitive radio environment.