This paper proposes a cognitive radio enabled LEO SatCom using RSMA radio access technique with the coexistence of GEO SatCom network. In particular, this work aims to maximize the sum rate of LEO SatCom by simultaneously optimizing the power budget over different beams, RSMA power allocation for users over each beam, and subcarrier user assignment while restricting the interference temperature to GEO SatCom. The problem of sum rate maximization is formulated as non-convex, where the global optimal solution is challenging to obtain. Thus, an efficient solution can be obtained in three steps: first we employ a successive convex approximation technique to reduce the complexity and make the problem more tractable. Second, for any given resource block user assignment, we adopt KKT conditions to calculate the transmit power over different beams and RSMA power allocation of users over each beam. Third, using the allocated power, we design an efficient algorithm based on the greedy approach for resource block user assignment. Numerical results demonstrate the benefits of the proposed optimization scheme compared to the benchmark schemes.

翻译：本文提出一种采用速率分裂多址接入技术的认知无线电赋能低轨卫星通信系统，其与地球同步轨道卫星通信网络共存。具体而言，本工作旨在通过同时优化不同波束的功率预算、每个波束上用户的RSMA功率分配以及子载波用户分配，在限制对GEO SatCom的干扰温度的同时，最大化LEO SatCom的总速率。该总速率最大化问题被建模为非凸问题，全局最优解难以直接获得。因此，可通过三个步骤获得高效解：首先采用逐次凸近似技术降低复杂度，使问题更易处理；其次，对于任意给定的资源块用户分配，利用KKT条件计算不同波束的发射功率及每个波束上用户的RSMA功率分配；最后，基于所分配的功率，设计一种基于贪心策略的资源块用户分配高效算法。数值结果表明，所提出的优化方案相较于基准方案具有显著优势。