Performance evaluation of channel coding and aperture averaging for the satellite-to-ground optical communications with APD receivers

In this paper, the synergy of the channel coding and aperture averaging is applied to the downlink optical channel for the low earth orbit (LEO) satellite. Bit error rates (BER) of the convolutional code and low-density parity code (LDPC) are evaluated versus different diameters for the optical systems with avalanche photodiode (APD) receivers. Results indicate that when the temporal correlation time τ₀ = 10 ms, the convolutional code satisfying the real-time delay constraint has practically no interest, because it doesn´t show significant performance improvement over the no-coding case. Moreover, the aperture averaging is shown to be robust across the a large range of zenith angles ζ ≤ 80°.