卫星数据链路干扰分析

本文对卫星通信的上、下行链路和转发器实施干扰的可行性进行了分析,并详细分析了上行干扰对透明转发器的影响.研究结果表明,对上、下行链路实施干扰的有效途径为升空平台(无人机或卫星)载有干扰设备;对透明转发器卫星通信系统,干扰的有效功率必须大于所有用户的总功率,宽带干扰或梳状谱干扰是较好的干扰方式.     

在微蜂窝码分多址小区的上行链路实现比特同步的设想

本文认为在微蜂窝小区的结构下,即蜂窝小区的半径在100m到200m时,可由小区基站发出比特同步信息,小区内的各手持机根据接收到的比特同步信息,实现上行链路的比特同步通信。本文的分析和计算表明,同步通信可显著地降低误码率。     

5G NR上行干扰问题研究

根据中国5G NR的频率使用方案,本文首先重点分析了2.6 GHz频段与4.9 GHz频段上5G NR上行面临的干扰风险,为5G NR规避相关干扰提供指导.然后通过外场干扰测试,掌握了5G NR网络性能与干扰强度间的关系,给出了全频带严重干扰时的5G NR干扰门限建议和NSA组网时的LTE锚点受扰门限建议.根据上述研究结果,本文提出了适合SA和NSA两种组网方式的5G NR干扰分析方法,为5G NR干扰分析的集中化和自动化提供指导.     

Up-link power control of satellite earth-stations as a fade countermeasure of 20/30 GHz communications systems

All 20/30 GHz satellite communications systems suffer from atmospheric attenuation in cloudy or rainy weather, particularly if high link availabilities are required. In FDMA systems the power transfer characteristic of each carrier is linear, so any up-link fade degrades the overall performance on a dB-by-dB basis. This, together with the fact that the 30 GHz up-link attenuation is much greater than the 20 GHz down-link attenuation, makes adaptive countermeasures of up-link fades most important. This paper shows how the overall link performance can be improved by applying up-link power control. It is explained how this improvement depends on the up-link/down-link balance, the dynamic range of the up-link power control, and the up-link and down-link atmospheric attenuation. If a small number of carriers can be allocated in an intermodulation-free frequency plan, the satellite transponder can be operated near saturation in order to optimize the down-link performance. Computer simulations of up-link power control for such an FDMA scheme have been performed based on measured three-carrier characteristics of a transponder TWT. It is shown that the overall link performance in faded conditions can be significantly improved with up-link power control. This may be utilized to increase the availability of a satellite link or to relax the earth-station performance in terms of G/T or EIRP if the link margin provided by an earth-station with fixed EIRP is satisfactory.