Cognitive radio architecture: Organizing computational intelligence for peer and network collaboration

Abstract

This chapter explores in detail the concept of cognitive radio architecture in centralized and ad hoc networks. Such architecture is paramount for establishing a cooperating platform of environment-aware nodes. The chief constituent elements of the cognitive radio architecture include functions implemented through components using a set of design rules. The synergy between software defined radio and cognitive principles is fully exploited by assuming that the cognitive radio architecture is based on a software defined radio endowed with a perceptive system capable of sensing the radio environment, in particular the use of the radio spectrum. This capability is complemented with an intelligent system able to understand the radio environment and, based on the user's needs or expectations, dynamically reconfigure the system taking into account spectrum usage. The so called cognition cycle is an architecture subsystem including an inference hierarchy, the temporal organization and flow of inferences and control states. The cycle continually observes the environment, orients itself, creates plans, decides, and then acts. The phases of inference from observation to action show the flow of inference, a top-down view of how cognition is implemented algorithmically. The inference hierarchy is the part of the algorithm architecture that organizes the data structures. The cognition functions are implemented via cognition elements consisting of data structures, processes and flows. These include data structures and related processing elements may be modeled as topological maps over abstract domains. The processing elements of the architecture, modeled topological maps like input, best-match and other maps, are described in detail in this chapter. As software defined radio is the fundamental platform for cognitive radio, the former is reviewed also in this chapter, including overviews of software radio architecture (SRA) and software communications architecture (SCA), the transition and evolution towards cognitive radio architecture, and other relevant technical aspects. © 2006 Springer. All Rights Reserved.