Satellite Ephemeris Broadcasting Architecture for 5G Integrated LEO Satellite Internet

This paper proposes a satellite ephemeris broadcasting architecture for 5G integrated low earth orbit (LEO) Satellite Internet based on two-line element (TLE) ephemeris. By periodically broadcasting the TLE ephemeris, which can be used to assist the user equipment (UE) for satellite selection, Doppler frequency offset and time advance (TA) pre-compensation, etc., the design of the 5G integrated LEO satellite air interface could be greatly simplified. The proposed architecture mainly comprises three stages, the generation, distribution and application of TLE ephemeris. (1) The accurate TLE ephemeris is generated by the simplified general perturbations-4 (SGP4) orbital model, whose input is obtained by the data combination of the orbital data acquired from the spaceborne global navigation satellite system (GNSS) and the satellite tracking station, respectively. (2) The generated ephemeris is sent to the internet, and then be uploaded to its corresponding LEO satellite by the feeder link. The UEs can either obtain the ephemeris from the satellite or from the terrestrial base station. (3) The UE equipped with GNSS system utilizes the TLE ephemeris to calculate the orbital information, Doppler frequency offset and timing advance, etc., so as to realize the efficient and reliable communication with the LEO satellites. The simulation results show that the proposed ephemeris broadcasting architecture can provide reliable and necessary priori information used for the entire physical layer communication process of 5G integrated LEO Satellite Internet over a period of time.