Heterogeneous Network for Inter-NanoSat Communication With Novel Modulation Schemes and Power Control

In this letter, the problems of using radio frequency (RF) or laser to enable inter-NanoSat communication is first analyzed, and the feasibility of adopting visible light communication (VLC) to replace RF and laser is investigated. Two optical modulation schemes with high flexibility and adaptability are proposed, namely improved asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) and improved direct current biased optical OFDM (DCO-OFDM). Then a heterogeneous optical network architecture is proposed for inter-NanoSat communication, in which NanoSats are grouped into pairs. The two NanoSats in each group utilize improved ACO-OFDM and improved DCO-OFDM respectively to balance optical energy efficiency and spectral efficiency and avoid inter-NanoSat interference. In addition, an optimization problem considering optical power control is formulated to minimize the total bit error rate (BER) of each group. Simulation results indicate that the proposed scheme is more suitable for practical scenarios and can obtain a gain of 3.7 dB at a BER of 10(-4).