Traffic Balancing Multibeam Antennas for Communication Satellites
Piero Angeletti, Juan Lizarraga Cubillos
Abstract
Broadband satellite systems rely on multibeam antennas for reusing the spectrum and, despite the numerous beam layout options, they have persistently adopted regular patterns to ease the antenna design. Regular beam patterns, however, ultimately undermine the system’s competitiveness as they limit the achievable throughput and prevent the full exploitation of the payload’s resources. The reason behind these limitations is the inherent mismatch between the uniform way regular beam patterns provide capacity and the nonuniform distribution of the traffic which results in underloaded beams with surplus capacity and overloaded beams with insufficient capacity to meet the demand. This compels the system to face the paradox of leaving capacity unused while there is still unmet demand. In this contribution, we propose to overcome these limitations by using nonregular beam patterns specifically designed to balance the traffic among beams and match the demand to the supply. We also present a methodology for designing such patterns with excellent results in satellite communications that can be broadly adopted in multiuser/multibeam wireless systems.