On the Deployment of Large-Scale High-Capacity Wireless Systems with Secondary Spectrum Access

Sammanfattning: The avalanche in mobile data consumption represents a big challenge for mobile networks operators and national regulators. This thesis focuses on finding additional spectrum to meet this demand in a cost-efficient way by considering shared spectrum access. Our studies aim at identifying key factors in achieving large-scale business success,quantifying the spectrum availability and identifying suitable regulatory/sharing polices for large-scale secondary access in the aeronautical and radar bands. This thesis proposes a research methodology, that considers business, technical and regulatory aspects involved in assessing commercial viability of large-scale deployment of wireless networks, employing vertical spectrum sharing in the aeronautical and radar bands. We pinpoint the following criteria which are critical in ensuring business success:spectrum availability, radio technology availability, low-cost end-userdevices, system scalability and quality of service. Our investigation centers on the technical aspects of these criteria, and thus deals mainly with the assessment of spectrum availability. The availability of spectrum opportunities is found to be ample for adjacent channel usage despite the strict requirements of the radar receiver. However, it is alsovery location-dependent and mostly non-contiguous.Finally, with regard to the regulatory aspects, our results show thatapplying regulatory policies, especially to the deployment of secondary users, can boost availability in cities or urban areas where the capacity demand is high. In addition, Licensed Shared Access (LSA) is identified as a suitable regulatory framework to meet tough protection criteria ofthe radar receivers and to apply the selected regulatory policies to improve exploitation of sharing opportunities. Based on our results and analysis, we conclude that there is a significant amount of spectrum opportunities for large-scale secondary access in the aeronautical and radar bands from the technical point of view. However, the commercial viability of secondary spectrum access is still undetermined giventhe remaining uncertainties regarding its total cost and the exact time needed for relevant technology to become available. Moreover, thereis no single answer to the commercial viability since it will most likelydepend on the country or region in question, which affects the spectrum availability, which in turn is a key criterion for business success. Futurework should therefore strive to clarify these uncertainties and to identify new responsibilities for all the entities involved in the LSA framework. Moreover, a quantitative evaluation would be needed to obtain more explicit conclusions on the business viability.