Precoding for Satellite Communications: Why, How and What Next?

Abstract

Precoding has stood out as a promising multi-user multi-antenna transmission technique to meet the emerging throughput demand of satellite communication systems while awaiting the technological maturity for exploiting higher bands. Precoding enables the reduction of interference among co-channel beams while improving spectral efficiency. Satellite systems offer multitude of system and service configurations, resulting in different precoder design methodologies. This article explores the motivation for the introduction of precoding, offers an insight to their theoretical development in diverse scenarios and presents some avenues for future development.

A Survey on Robust Modulation Requirements for the Next Generation Personal Satellite Communications

“…Therefore, it is of great necessity to conduct further research concerning the application of multiantenna systems in a personal SATCOM scenario at the SAT, user terminal, and earth station level. For example, the antenna size, the number of antennas required, interference mitigation, the use of codes, resource allocation, optimal beamforming architectural design, to mention but a few (Yingda et al, 2006;Alegre-Godoy and Vazquez-Castro, 2013;Mysore et al, 2021).…”

Radio Resource Management Techniques for Multibeam Satellite Systems

“…Here, spatial multiplexing 1 may refer to the multiple beams or to precoding using multiple transmit antennas at the satellite. Hence, the most common RRM problems target the optimal distribution of signal bandwidth, time slots and transmit power among the users as well as the design of precoding vectors [4], [5]. Note that neighboring beams may produce interference for the adjacent users, which needs to be accounted for in the system design.…”

5G New Radio Non-terrestrial Networks Multiuser Precoding

“…So far, the required adaptations of space and ground segment and the practical impairments have not allowed the commercial development of precoding solutions. However, it is envisaged that the proliferation of flexible payloads and direct radiating array antenna systems may become a game changer here, combining flexible user scheduling, band allocation and beamforming/precoding solutions for the most efficient use of all satellite resources [9]- [10]. This vision brings satellite systems closer to the terrestrial multi-user (MU) multiple-input-multiple-output (MIMO) framework targeted by NR procedures, but significant differences need to be still considered in terms of transmitting antenna dimensions and capabilities, targeted number of simultaneous users, channel impairments, etc.…”