ISBN 9783843937474

978-3-8439-3747-4, Reihe Elektrotechnik

Arun Ashok
High Linear Transmitter for LTE/WLAN Cognitive Radio Applications

149 Seiten, Dissertation Rheinisch-Westfälische Technische Hochschule Aachen (2018), Hardcover, A5

Zusammenfassung / Abstract

Due to the explosive growth of broadband and mobile services, the spectrum has gone from an abundant to a rare resource. Due to the differences in the spectrum allocation, regulations and modes of use between the countries, the available spectrum is severely underutilized. Spectrum utilization could be effectively improved with a radio unit having spectral awareness. Such a radio which is aware of its surrounding and hence can decide the transmission parameters can be called as a cognitive radio and is an ideal solution to the spectrum scarcity problem. The frequencies which are underutilized and open to be used for wireless communications range from 470 MHz to 790 MHz in the UHF band as well as those greater than 5 GHz. Transition of terrestrial TV broadcasting from analogue technology to digital TV transmission has resulted in sparsely occupied spectrum. The frequencies which are underutilized as a result are termed as TV white spaces (TVWS). Studies about the availability of TV channels shows that 48 % and 56 % of the frequencies between 470 MHz - 790 MHz are underutilized in Germany and Europe as a whole respectively. The aim of this thesis is to design and develop a wide band radio front end for a cognitive radio transmitter which, with the knowledge of vacant frequencies in the UHF band can utilize the unused frequencies without impairing the nearby already existing users. For such a cognitive radio, primary users will be mainly composed of TV stations and wireless microphones and secondary users will be those who wishes to exploit the vacant spectrum opportunistically. For WLAN and LTE as secondary users, this thesis addresses the system requirements first deriving the system specifications from the ETSI EN 301598, thereby devising an optimum RF front-end architecture. Several architectures have been compared leading to development and characterization of two prototypes LTE and WLAN based secondary users. Take cue from the system study, an integrated system solution is designed to address low cost solution for a LTE/WLAN cognitive radio.