Massive MIMO Hybrid Precoding for LEO Satellite Communications With Twin-Resolution Phase Shifters and Nonlinear Power Amplifiers

Abstract

The massive multiple-input multiple-output (MIMO) transmission technology has recently attracted much attention in the non-geostationary, e.g., low earth orbit (LEO) satellite communication (SATCOM) systems since it can significantly improve the energy efficiency (EE) and spectral efficiency. In this work, we develop a hybrid analog/digital precoding technique in the massive MIMO LEO SATCOM downlink, which reduces the onboard hardware complexity and power consumption. In the proposed scheme, the analog precoder is implemented via a more practical twin-resolution phase shifting (TRPS) network to make a meticulous tradeoff between the power consumption and array gain. In addition, we consider and study the impact of the distortion effect of the nonlinear power amplifiers (NPAs) in the system design. By jointly considering all the above factors, we propose an efficient algorithmic approach for the TRPS-based hybrid precoding problem with NPAs. Numerical results show the EE gains considering the nonlinear distortion and the performance superiority of the proposed TRPS-based hybrid precoding scheme over the baselines.

Energy-Efficient Beamforming Design for Integrated Sensing and Communications Systems

“…Remark 1: Our proposed Algorithm 1 employs Dinkelbach's extended algorithm [35], which is adapted for nonconvex subproblems encountered during iterations. In fact, Dinkelbach's extended algorithm has been widely adopted for handling resource allocation problems in wireless communications, e.g., [36], [37]. As shown in [36], since the solution of each subproblem can be obtained by applying SCA and the sequence generated during iterations is non-decreasing, Algorithm 1 is guaranteed to converge to an efficient solution of problem (11)…”

Joint beam power and pointing management in multi‐beam low earth orbit and low earth orbit co‐existing satellite system

“…Thus, this paper proposes joint beam power and pointing management (JBPPM) based on particle swarm optimization (PSO) to solve the interference coexistence problem between the LEO–LEO co‐existing system. The proposed scheme is different from beamforming (BF), which adjusts the beam pointing and power of the same array antenna to improve energy efficiency 12–14 . In the proposed scheme, beam power control and beam pointing optimization are applied to satellite and ground users, respectively.…”

“…The proposed scheme is different from beamforming (BF), which adjusts the beam pointing and power of the same array antenna to improve energy efficiency. [12][13][14] In the proposed scheme, beam power control and beam pointing optimization are applied to satellite and ground users, respectively. Specifically, satellites in the LEO2 secondary system adopt beam power control to reduce interference to the primary system user.…”