In this letter, we investigate the beamforming optimization problem in a non-orthogonal multiple access (NOMA) based multibeam satellite system. The design key is to minimize the transmit power on-board the multibeam satellite system with the perfect and imperfect channel state information (CSI), while meeting the quality of service (QoS) for satellite users. Owing to the intractability and non-convexity of the original optimization problem induced by the user’s CSI uncertainty, we consider the robust beamforming scheme to convert the original optimization problem into a tractable convex optimization problem by S-Procedure and semidefinite relaxation (SDR) techniques and obtain the optimal solutions. Finally, numerical simulations demonstrate the superiority and validity of the proposed beamforming optimization algorithms.

中文翻译：

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具有非正交多址接入的多波束卫星系统中的稳健波束成形

在这封信中，我们研究了基于非正交多址 (NOMA) 的多波束卫星系统中的波束成形优化问题。设计的关键是在满足卫星用户的服务质量 (QoS) 的同时，最大限度地减少具有完善和不完善信道状态信息 (CSI) 的多波束卫星系统的发射功率。由于用户的 CSI 不确定性导致原始优化问题的难处理性和非凸性，我们考虑了鲁棒波束成形方案，通过 S-Procedure 和半定松弛 (SDR) 技术将原始优化问题转换为易于处理的凸优化问题和得到最优解。最后，数值模拟证明了所提出的波束成形优化算法的优越性和有效性。