The number of satellites has been increasing in both geostationary (GEO) and non-geostationary (NGEO) earth orbits. Due to the limited availability of spectrum resources, the interference risk among these satellite networks has been increasing consequently. In such a scenario, the protection of existent GEO transmissions is crucial. In this paper, the co-existence downlink interference from a typical low earth orbit (LEO) constellation to earth stations of GEO satellites is examined for minimization of exclusion zone on the equatorial region. Two different operational scenario based on modulation and coding (MODCOD) with/without spread spectrum for the LEO system are considered. A multiobjective optimization problem (MOP) is formulated for nondominant solutions set based on exclusive angle minimization and bandwidth utilization of the LEO link. It is shown that the exclusive angle can be reduced up to 21.3% and 19.6%, compared with the initial anchor point at the transmission bit rates of 100 and 200 Mbps, respectively. The proposed optimal operational setting minimizes the interference risk to the GEO satellite network as well as maintains quality of service (QoS) for the LEO communication network. The results provide optimal operational mode selection for LEO satellite operators and/or decision makers.

中文翻译：

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共存地球静止卫星和非地球静止卫星的排除区最小化和最佳运行模式选择

地球静止 (GEO) 和非地球静止 (NGEO) 地球轨道上的卫星数量一直在增加。由于频谱资源的有限可用性，这些卫星网络之间的干扰风险因此一直在增加。在这种情况下，保护现有的 GEO 传输至关重要。在本文中，研究了典型低地球轨道 (LEO) 星座对 GEO 卫星地球站的共存下行链路干扰，以最小化赤道地区的禁区。考虑了 LEO 系统的两种不同的基于调制和编码 (MODCOD) 的操作场景，有/没有扩频。基于LEO链路的独占角度最小化和带宽利用，为非优势解集制定了多目标优化问题（MOP）。结果表明，与传输比特率分别为 100 和 200 Mbps 的初始锚点相比，独占角可以减少高达 21.3% 和 19.6%。建议的最佳操作设置最大限度地减少了对 GEO 卫星网络的干扰风险，并保持了 LEO 通信网络的服务质量 (QoS)。结果为 LEO 卫星运营商和/或决策者提供了最佳运行模式选择。