ABSTRACT
Contents 4.1 Cognitive Networks and Dynamic Spectrum Access . . . . . . . . . . . . . . . . .87 4.2 The Challenge of Cognitive Network Rendezvous
and Coordination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 4.2.1 Static Control Channels-Global System
for Mobile (GSM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91 4.2.2 In-Band Control Signaling-WiMAX . . . . . . . . . . . . . . . . . . . . . . . . . .92 4.2.3 Dynamic Spectrum Access Networks . . . . . . . . . . . . . . . . . . . . . . . . .94
4.3 Cognitive Network Rendezvous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95 4.3.1 A New Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96
4.4 Cyclostationary Signatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98 4.5 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Haykin1 defines a cognitive radio as “an intellegent wireless communication system that is aware of its environment and uses the methodology of understanding-by-building to learn from the environment and adapt to
statistical variations in the input stimuli” with the overarching aim of providing reliable communication whenever and wherever needed while efficiently using the resources available to it. The cognitive radio is built upon software-defined radio (SDR) technology, and a great deal of research effort is currently devoted to the development of radio devices capable of cognitive operation. Cognition in this sense includes making observations of the operating environment, using these observations to arrive at optimization decisions, and reconfiguring device operating parameters while building upon past experience to learn from mistakes and proactively adapt to the environment.
