Abstract:The rapid development of broadband satellite Internet has brought satellite communications into a new era. The establishment of large-scale low-orbit satellite constellations has gradually saturated spectrum resources. , the high degree of overlap in frequency usage leads to serious interference problems between various satellite communication systems. Satellite payloads usually use phased array antennas for communication, and beamforming at the transceiver end is used to reduce system interference. An adaptive beamforming algorithm is used at the receiving end to suppress interference through adaptive zeroing; a low side-lobe beamforming algorithm is used at the transmitting end to reduce interference by imposing specific constraints on the side lobes to lower the side-lobe levels. Three anti-interference beamforming algorithms are analyzed respectively for the ground receiving end and the satellite transmitting end, providing beam-level methods to reduce interference problems in satellite communication systems.
Keywords:Low orbit satellite; smart antenna; adaptive beamforming; low side lobe beamforming
0 Preface
In recent years, terrestrial communication technology has rapidly iterated, and 5G mobile communication technology has promoted the Internet of Everything to gradually move towards the Intelligent Internet of Everything. As an effective supplement to terrestrial communication systems, broadband satellite Internet has greatly promoted the development and application of satellite communication technology. Thanks to the advantages of Low Earth Orbit (LEO) satellites such as low orbit altitude, short transmission delay, small space path loss, and low launch cost, large-scale low-orbit satellite constellations represented by Starlink, OneWeb, Kuiper, etc. have rapidly developed Rise, the integration of multiple LEO satellites and ground networks can provide broadband Internet access services for ground terminals and space users. Satellite communications mainly use frequency bands such as C, The operating frequencies of satellites will highly overlap, and LEO satellites will cause potentially harmful interference to GSO satellites and other LEO satellites in the same frequency band. The potential interference existing in the broadband low-orbit satellite communication system can be divided into the following three types according to the interference source: interference from the GSO satellite system to the LEO satellite system, interference from the LEO satellite system to the GSO satellite system