Resource Management Optimization for Interference-Limited Multi-User Satellite Networks (ROIMUS)

未来的卫星通信有两大特点。首先，馈送的数量，即，卫星上的天线元件的数量大约为几百个。另外，在大量载波上的时隙中传输是可能的。第二，必须服务于静态和移动的用户，其信道具有视线连接的特性，即，对于这样的卫星系统，波束形成和用户调度的联合设计被认为是能够处理基于鲁棒问题公式的静态和移动的用户。基于对偶分解方法和目标的单调性，得到了全局最优解。由于尺寸大，即，对于许多天线、载波和用户，必须采用算法来找到低复杂度的解决方案。另一方面，大的维数的问题允许一个大的系统analysis.Besides自适应波束形成和国家的最先进的固定波束形成与调度，一个离散的自适应波束形成方案进行了研究，其中地面站可以选择一组离散的波束形成模式。此外，卫星集群的情况下，被认为是除了传统的单卫星设置。卫星群的设计的额外困难是波束形成器的单独功率约束和结构约束，其中用户由几个卫星服务。此外，不同的合作水平的地面站控制的卫星进行了研究。

Future satellite communications have two major properties. First, the number of feeds, i.e., the number of antenna elements, at the satellite are in the order of several hundreds. Additionally, transmission is possible in time slots on a large number of carriers. Second, static and mobile users must be served, whose channels have the properties of a line-of-sight connection, i.e., the channel covariance matrices are rank one.For such satellite systems, the joint design of beamforming and user scheduling is considered that is able to deal with static and mobile users based on a robust problem formulation. Globally optimal solutions are derived based on a dual decomposition approach and monotonicity properties of the objective. Due to the large dimensions, i.e., many antennas, carriers, and users, heuristics must be employed to find low-complexity solutions. On the other hand, the large dimensionality of the problem allows for a large system analysis.Besides the adaptive beamforming and the state-of-the-art fixed beamforming with scheduling, a discretely adaptive beamforming scheme is investigated where the ground station can choose over a set of discrete beamforming patterns. Moreover, the case of a satellite cluster is considered besides the conventional single satellite setup. The additional difficulties of the design for a satellite cluster, where the users are served by several satellites, are the separate power constraints and the structural constraints of the beamformer. Additionally, different cooperation levels of the ground stations controlling the satellites are investigated.