Phase-Only Transmit Beamforming for Spectrum Sharing Microwave Systems

Konferenz: WSA 2016 - 20th International ITG Workshop on Smart Antennas
09.03.2016 - 11.03.2016 in München, Deutschland

Tagungsband: ITG-Fb. 261: WSA 2016

Seiten: 7Sprache: EnglischTyp: PDF

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Vazquez, Miguel Angel; Blanco, Luis (Centre Tecnologic de Telecomunicacions de Catalunya (CTTC), Spain)
Perez-Neira, Ana; Lagunas, Miguel Angel (Centre Tecnol`ogic de Telecomunicacions de Catalunya (CTTC) & Dept. of Signal Theory and Communications Universitat Politecnica de Catalunya, Spain)

This paper deals with the problem of phase-only transmit beamforming in spectrum sharing microwave systems. In contrast to sub-6 GHz schemes, general microwave systems require a large number of antennas due to its huge path loss. As a consequence, digital beamforming needs a large number of computational resources compared to analog beamforming, which only needs a single radio-frequency chain, results the less computational demanding solution. Analog schemes are usually composed by a phase shifter network whose elements transmit at a certain fixed power so that the system designer shall compute the phase values for each element given a set of directions. This approach leads to non-convex quadratic problems where the traditional semidefinite relaxation fails to deliver satisfactory outcomes. In order to solve this, we propose a nonsmooth method that behaves well in several scenarios. Numerical evaluations in different spectrum sharing scenarios, which show the performance of our method, are provided.