Efficient Seamless Coverage of High Throughput Satellites with Irregular Coverage Shapes

High throughput satellites (HTS), which can provide wide coverage, are recognized as a promising extension and supplement to achieve global coverage for the space-air-ground integrated network (SAGIN). Different to current literature on seamless coverage of HTS which considers that the shapes of multi-spot beam coverage regions are regular, this paper considers a practical HTS system, in which the multi-spot beams with irregular coverage regions are discussed, and the limitations of spot beam resource and coverage overlapping are taken into account. In order to achieve efficient seamless coverage of HTS, a grid division based multi-spot beam footprint planning (GD-MBFP) scheme is proposed with a given maximum coverage overlap ratio, aiming to minimize the number of spot beams. Meanwhile, for GD-MBFP scheme, a grid division based singlespot beam coverage calculation (GD-SBCC) method is proposed to obtain the irregular coverage regions of spot beams accurately. Numerical results validate the effectiveness of the proposed GD-MBFP scheme. Given a maximum coverage overlap ratio of ηmax=30%, the number of spot beams achieving seamless coverage with the proposed GD-MBFP scheme is only 37.9% of that achieving seamless coverage with cellular beam footprint planning (CBFP) scheme. Meanwhile, the average SINR of UTs with the proposed GD-MBFP scheme is 1.58 times that with CBFP scheme. The average throughput of spot beam with the proposed GD-MBFP scheme is improved by 30.4% than that with CBFP scheme.