Satellite communication is considered as an efficient way to achieve the reliable communication for worldwide users. To further enhance the achievable rate of the satellite system, we propose joint beamforming schemes of an integrated satellite-terrestrial self-backhauled (ISTS) system, in which the satellite backhaul and terrestrial access links are operating at the same millimeter wave band. Specifically, the earth station and the base station (BS) constitute a self-backhauled relay to forward the satellite signals to the terrestrial users. A sum rate maximization problem is formulated under the constraints of the maximum power requirements of the satellite and the BS, the minimum quality-of-service requirements of the terrestrial users, and the maximum satellite backhaul capacity. To obtain some insights, we first assume that the perfect channel state information (CSI) on the satellite and terrestrial links is known and transform the formulated optimization problem to a standard difference of convex problem. Then we solve it iteratively by adopting the convex-concave procedure approach. Furthermore, when only imperfect CSI on the satellite and terrestrial links is available, we employ a iterative penalty function algorithm associated with the sequential convex approximation method and the S-procedure approach to obtain suboptimal beamforming vectors. Finally, simulation results demonstrate that the proposed joint beamforming schemes have better performance compared with other benchmark schemes and the ISTS architecture is suitable for the satellite systems in various orbits.

中文翻译：

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用于集成毫米波卫星-地面自回程网络的联合波束成形

卫星通信被认为是实现全球用户可靠通信的有效方式。为了进一步提高卫星系统的可实现速率，我们提出了集成卫星-地面自回程 (ISTS) 系统的联合波束成形方案，其中卫星回程和地面接入链路工作在相同的毫米波频段。具体来说，地球站和基站（BS）构成一个自回程中继，将卫星信号转发给地面用户。在卫星和基站的最大功率要求、地面用户的最低服务质量要求和最大卫星回程容量的约束下，制定了和速率最大化问题。为了获得一些见解，我们首先假设卫星和地面链路上的完美信道状态信息 (CSI) 是已知的，并将公式化的优化问题转换为凸问题的标准差。然后我们采用凸凹过程方法迭代求解。此外，当卫星和地面链路上只有不完美的 CSI 可用时，我们采用与顺序凸逼近方法和 S 过程方法相关的迭代惩罚函数算法来获得次优波束成形向量。最后，仿真结果表明，所提出的联合波束成形方案与其他基准方案相比具有更好的性能，并且 ISTS 架构适用于各种轨道的卫星系统。