Contribution to the characterization and evaluation of multiple antenna systems for communications: prototyping, propagation and antenna perspective

Abstract

The advent of new services and applications in mobile and wireless communications, most of them based on high data rates, is helping to reactivate the Telecommunication market.Moreover, current trends seem to point towards the preference for wireless connections to Internet instead of the traditional wired ones, towards the growing of data exchanges (for example with web 2.0 and peer-to-peer applications) and towards the exponential increase in the number of devices connected to Internet (as in the proposed future "Internet of things"). A clear consequence of all these trends is the significant increase in data rate requirements for wireless and mobile communications. As a result, research on new techniques that allow to increase data rate and system performance has been boosted by the market needs.Having intensively utilized frequency, time and even code diversity resources, spatial diversity offered by the radio channel has been proposed as an alternate method of great interest to be exploited. Advances in signal processing platforms have improved the computational capacities in digital signal processing, opening new options for signal processing for antenna arrays. The main objective of this thesis has been to investigate the possibilities for radiocommunication systems that are based on the use of multiple antennas to take advantage of the available spatial diversity in the channel. Moreover, current open issues and problems that prevent multi-antenna systems from being widely adopted have been thoroughly analysed, with special emphasis on real implementation issues. Novel approaches to evaluate multi-antenna systems have been proposed, and results regarding real prototypes have been presented and discussed.