An Inter-Doppler Interference Constrained OC-DFE for OTFS in UWA Communications

Orthogonal Time Frequency Space (OTFS) modulation presents a promising approach for underwater acoustic (UWA) communication. This study proposes an iterative decision feedback equalizer based on optimal combining (OC) for UWA-OTFS systems, addressing challenges posed by the fullmatrix channel characteristics in the delay-Doppler domain. The proposed detector maximizes the signal-to-interference-plusnoise ratio of the combined signal. Furthermore, by introducing inter-Doppler interference depth, the OC detector dynamically constrains the number of combining terms. Simulation results demonstrate that the proposed detector effectively balances bit error rate performance with computational complexity.