S.V. Zavjalov1, A.S. Orlova2, I. Lavrenyuk3, S.B. Makarov4, A.A. Kuznetsova5, A.A. Chekireva6, S.V. Volvenko7

1-7 Peter the Great St. Petersburg Polytechnic University (St. Petersburg, Russia)

1 zavyalov_sv@spbstu.ru; 2 ovsyannikova_as@spbstu.ru; 3 lavrenyuk_i@spbstu.ru; 4 makarov_sb@spbstu.ru; 5 kuznetsova_aa@spbstu.ru; 6 chekireva_aa@spbstu.ru; 7 svolvenko@spbstu.ru

Formulation of the problem. The widespread use of small satellites necessitates maximizing data transfer rates due to the limited duration of communication sessions. At the same time, it is necessary to maintain data reception immunity close to theoretically possible, while taking into account the technical and economic limitations of the small satellite radio system. CubeSat missions using the DVB-S2X protocol to relay data from low-Earth orbit face energy constraints that determine the hardware capabilities and achievable data transfer rates.

With increasing information volumes and the need to transmit it in a limited time, it is necessary to increase the transfer rate by using FTN technology. However, the use of "classical" pulse shapes (e.g., RRC) leads to significant energy losses with increasing symbol rate. Under these conditions, one way to improve the efficiency of DVB-S2X systems is to use optimal signals. This concept of optimal signals involves the use of optimal pulses synthesized in accordance with specified optimization criteria and constraints. This paper proposes to use optimal pulses instead of RRC pulses to double the symbol rate while maintaining high receive noise immunity (BER).

Goal. To evaluate the possibility of increasing the message transmission rate during packet operation of a modem based on the DVB-S2X protocol by using optimal signals that ensure minimal energy losses and are constructed on the basis of amplitude pulses whose duration exceeds the transmission time of a message bit.

Results. The feasibility of using optimal signals with extended amplitude trajectories in a data transmission system in accordance with the DVB-S2X standard is demonstrated. Simulation modeling demonstrates that using optimal signals constructed from amplitude pulses whose duration exceeds the message bit transmission time enables minimal energy loss while doubling the transmission rate in the allocated frequency band. Using optimal signals doubles the spectral efficiency to 2.4 (bit/s)/Hz, which is higher than using RRC signals, which provide a spectral efficiency of 1.2 (bit/s)/Hz.

Practical significance. Based on the obtained results, a modem based on the DVB-S2X protocol can be developed for the radio transmission system of small spacecraft, ensuring a doubling of the information transfer rate and spectral efficiency relative to existing analogues with minimal energy losses.

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