Recent Advances on Radio-Frequency Design in Cognitive Radio

Abstract

With the growth of mobile data applications, the spectrum allocation is becoming very scarce. To ease congestion and boost speeds, cognitive radio (CR) is currently seen as a major solution and expected to be the key player in the new wireless technologies. In this paper, we will start by introducing the cognitive radio systems, followed by exploring the challenges in designing RF engine, along with an investigation of its antennas, amplifiers, oscillators, and the components that are expected to operate over a wide range of frequencies.

Nature‐inspired optimisation algorithms assisted realisation of green communication via CR:a comparison study

“…For CR applications, the transmitter needs to operate at different frequency ranges. Thus we require a broadband linear PA having high efficiency [4].…”

A Refinement of the Square Wave Phase Noise Evaluation

“…A common communication arrangement consists of an oscillator (usually nearly sinusoidal), whose waveform is converted to rectangular by some kind of square wave forming circuit often followed by digital frequency dividers. An important present-day example is the local oscillator frequency synthesis in highly integrated receivers for cognitive and software radio applications where the wide range of frequencies needed is obtained by relatively narrow range PLLs followed by frequency divider chains [1][2][3]. The Square Wave (SW) may not physically exist.…”