A system approach to enable digital beamforming with direct radiating arrays: The joint use of precoding and sparse arrays

Florian Vidal, Hervé Legay, George Goussetis, Andrea Segneri

Research output: Contribution to journalArticlepeer-review

Abstract

Digital beamforming with an active array antenna has become, these past years, the holy grail for flexible satellite payloads. This architecture enables a power, frequency and beam steering flexibility that meets the requirements of a wide range of user terminal distributions. Matching these distributions may be challenging, especially if user terminals are co-located. In this case, narrower beams are needed to utilise high-frequency reuse factors while avoiding inter-beam interference. Small beamwidths, however, require large antenna diameters, which implies for conventional antenna arrays many radiating elements and subsequently an increased complexity. A way to reduce the number of radiating elements is to resort to sparse arrays with an irregular layout of radiating elements. A disadvantage of this type of antenna is their high side lobe levels when scanning the beams. A robust on-board precoding strategy based on the knowledge of the users' positions and the antenna gain over the coverage is proposed to mitigate the interference arising from high side lobe levels. A circular direct radiating array and a sparse direct radiating array based on a sunflower design are compared with respect to the capacities they can achieve, and the complexity of the processor required to perform full digital beamforming.

Original languageEnglish
Pages (from-to)645-660
Number of pages16
JournalInternational Journal of Satellite Communications and Networking
Volume39
Issue number6
Early online date1 Jun 2021
DOIs
Publication statusPublished - Nov 2021

Keywords

  • broadband
  • digital beamforming
  • MEO satellite
  • multibeam
  • precoding
  • SDMA
  • sparse array antenna

ASJC Scopus subject areas

  • Media Technology
  • Electrical and Electronic Engineering

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