Performance Analysis of LDPC-OTFS Joint Systems in Satellite-Hypersonic Vehicle Communications

Next-generation satellite communication systems necessitate reliable transmission capabilities in hypersonic mobility scenarios, where extreme Doppler frequency offset (DFO) and complex noise environments degrade channel conditions. Unlike conventional orthogonal frequency division multiplexing (OFDM) that exhibits significant inter-symbol interference (ISI) and inter-carrier interference (ICI) in ultra-high mobility, Orthogonal time frequency space (OTFS) modulation transforms time-varying channels into sparse delay-Doppler (DD) domain, effectively resisting hypersonic vehicle-induced DFO. This paper investigates the integration of Low-Density Parity-Check (LDPC) codes with OTFS modulation to enhance spectral efficiency and transmission reliability in ultra-high mobility scenario. This study evaluates the link performance of coded OTFS systems under non-terrestrial network (NTN) channel conditions, analyzing the impact of terminal velocity variations and proposing optimization strategies. Experimental results demonstrate that the LDPC-OTFS system achieves superior robustness in Mach-level mobility scenarios, although increasing mobility levels necessitate adaptive decoding parameter adjustments to maintain optimal coding gain.