ABSTRACT
The wireless industry continues to flourish at breakneck speeds. As a result, spectral congestion caused by wireless user traffic has already become a significant concern that threatens further growth of the technology [1,2]. However, this congestion is primarily due to suboptimal frequency usage arising from the inflexibility of the spectrum licensing process. This suboptimal spectrum allocation and its consequent inefficiency can be solved by utilizing the concept of dynamic spectrum access. This allows other users to utilize temporarily unused spectrum for communications. Typically, a software-defined radio (SDR) hardware is envisioned for exploiting dynamic spectrum access using cognitive radio (CR) capability. In this chapter, we define the CR in the narrow sense of an intelligent device that is able to dynamically adapt and negotiate wireless frequencies and communication protocols for efficient communications. To enable this capability, each participating device needs to have many features such as geolocation, analysis of the external communications environment, sensing the dynamic spectrum usage, and the ability to change the frequency and bandwidth of transmission, adjust the output power level, and even alter transmission parameters and protocols [3].
