To provide global service with low latency,the broadband low earth orbits(LEO)satellite con-stellation based communication systems have become one of the focuses in academic and industry.To allow for wideband access for user links,the feeder link of LEO satellite is correspondingly required to support high throughput data communications.To this end,we propose to apply line-of-sight(LoS)multiple-input multiple-output(MIMO)transmission for the feeder link to achieve spatial multiplexing by optimizing the antenna arrangement.Unlike the LoS MIMO applica-tions for static scenarios,the movement of LEO satel-lites make it impractical to adjust the optimal antenna separation for all possible satellite positions.To ad-dress this issue,we propose to design the antenna placement to maximize the ergodic channel capacity during the visible region of the ground station.We first derive the closed-form probability distribution of the satellite trajectory in visible region.Based on which the ergodic channel capacity can be then calculated numerically.The antenna placement can be further optimized to maximize the ergodic channel capacity.Numerical results verify the derived probability distri-bution of the satellite trajectory,and show that the pro-posed LoS MIMO scheme can significantly increase the ergodic channel capacity compared with the exist-ing SISO one.

Lingxuan Li;Tingting Chen;Wenjin Wang;Xiaohang Song;Li You;Xiqi Gao

National Mobile Communications Research Laboratory,Southeast University,Nanjing 210096,China;Vodafone Chair Mobile Communications Systems,Technische Universit?t Dresden,01062 Dresden,Germany

中国通信（英文版）

[1]Lingxuan Li;Tingting Chen;Wenjin Wang;Xiaohang Song;Li You;Xiqi Gao-.LoS MIMO Transmission for LEO Satellite Communication Systems)[J].中国通信（英文版）,2022(10):180-193

stellation

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