Cognitive Radio Circuits and Systems - Application to Digitizers

Abstract

This paper gives an overview of Cognitive-Radio (CR) circuits and systems, that will enable the implementation of new technology paradigms such as software-defined electronics and Artificial Intelligence (AI) managed Internet-of-Things (IoT). A survey of the state of the art, trends and design challenges is presented from a top-down perspective -from system-level to circuit and chip implementation. As an application, special emphasis is put on analog/digital interfaces as one of the key building blocks in CR-based devices. Cutting-edge architectures -mostly based on ⌃ Modulators (⌃ Ms) -are discussed, as well as the best candidate circuit strategies to implement CRbased digitizers in deep nanometer CMOS. 1

AI-Managed Cognitive Radio Digitizers

“…At the same time, more and more digital circuitry is being embedded to improve the performance of ASP circuits, by means of calibration, tuning, etc, that try to alleviate the limitations of nanometer CMOS analog circuits [134]. These features can be enhanced by the action of an embedded AI engine to manage the operation of the analog/digital interface [20].…”

“…As stated above, CR-based ADCs require not only digitize GHz signals but also to seamlessly hop from one frequency band to another, according to the information sensed from the electromagnetic spectrum. This feature can be realized by BP-Σ∆M ADCs with a widely tunable notch frequency, f n , while keeping the required resolution over the digitized band [20], [76]. To illustrate this approach, let us consider a second Σ∆M chip example, designed in 65-nm CMOS, which consists of a 4th-order loop filter made up of invertedbased Gm-LC resonators and a 4-bit quantizer, conceptually depicted in Fig.…”

“…), battery status and energy consumption. However, the practical realization of CR-based IoT devices requires highly programmable digital-friendly analog/RF front-ends [20].…”