  Small satellites in Low Earth Orbit (LEO) attract much attention from both
industry and academia. The latest production and launch technologies constantly
drive the development of LEO constellations. However, the wideband signal,
except text messages, cannot be transmitted directly from an LEO satellite to a
standard mobile cellular phone due to the insufficient link budget. The current
LEO constellation network has to use an extra ground device to receive the
signal from the satellite first and then forward the signal to the User
Equipment (UE). To achieve direct network communications between LEO satellites
and UE, we propose a novel distributed beamforming technology based on the
superposition of electromagnetic (EM) waves radiated from multiple satellites
that can significantly enhance the link budget in this paper. EM full-wave
simulation and Monte Carlo simulation results are provided to verify the
effectiveness of the proposed method. The simulation results show a nearly 6 dB
enhancement using two radiation sources and an almost 12 dB enhancement using
four sources. The received power enhancement could be doubled compared to the
diversity gain in Multiple-Input and Single-Output (MISO). Furthermore, other
practical application challenges, such as the synchronization and Doppler
effect, are also presented.
