Abstract
In traditional configurations where Low Earth Orbit Satellites (LEOs)
are used in conjunction with ground multi-antenna terminals to create a
virtual Multiple Input Multiple Output (MIMO) system, the high-speed
mobility of LEOs results in an unstable MIMO system topology, which
consequently affects the stability of system capacity. This paper
introduces two space-ground cooperation modes to enhance the stability
of MIMO system capacity. The first method optimizes channel capacity by
appropriately allocating the beam power of relay stations, allowing
relay stations to achieve transparent forwarding through satellites. The
second method involves rotating the angle of the user’s receiving
antenna to counteract channel variations caused by changes in satellite
positions. Simulation results indicate that both methods can effectively
improve the minimum channel capacity, with transparent forwarding
offering an enhancement of approximately 22.7%, while the rotational
antenna approach can achieve a performance gain of at least 36.3%, even
under limited rotation angles.