ABSTRACT
Contents 15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 15.2 Analytical Models at Multiple Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
15.2.1 Modeling of Available Spectrum Allocation . . . . . . . . . . . . . . 386 15.2.2 Modeling of Power Control and Scheduling . . . . . . . . . . . . . 388 15.2.3 Flow Routing and Link Capacity Model . . . . . . . . . . . . . . . . . . 392
15.3 Case Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393 15.3.1 Case A: Subband Division and Allocation Problem. . . . . . 394 15.3.2 Case B: Power Control Problem . . . . . . . . . . . . . . . . . . . . . . . . . . 398
15.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404 Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405
15.1 Introduction A cognitive radio (CR) is a frequency-agile data communication device with a rich control and monitoring (spectrum sensing) interface [11]. It capitalizes on advances in signal processing and radio technology, as well as recent changes in spectrum policy. A CR node constantly senses the spectrum to detect any change in white space; its frequency-agile radio module is
capable of reconfiguring RF and switching to newly-selected frequency bands. A CR can be programmed to tune to a wide spectrum range and operate on any frequency band in the range.
