Hamming Distance Optimized Underwater Acoustic OTFS-IM Systems

Abstract

The orthogonal time frequency space (OTFS) modulation technique can provide reliable communication in time-varying channels. Due to the dispersive characteristics of underwater acoustic channels, this paper proposes an OTFS-IM underwater acoustic communication system based on Hamming distance optimization to reduce the impact of dispersion in underwater acoustic communication. Firstly, the OTFS-IM underwater acoustic communication system is introduced, which introduces index modulation into the Delay–Doppler (DD) domain to make the OTFS system have stronger anti-Delay–Doppler capability. In contrast, since there is index sequence redundancy in a specific index combination, a Hamming distance optimization model is used to eliminate the redundant combination in the specific index combination sequence and further improve the bit error rate performance of the system. In addition, the Hamming distance optimized OTFS-IM underwater acoustic communication system is verified by simulation analysis. The results show that the proposed Hamming distance optimized OTFS-IM can achieve more reliable bit error rate performance.

A Method for Underwater Acoustic Target Recognition Based on the Delay-Doppler Joint Feature

“…Compared to the traditional method, it has a lower mean square error. Guo et al [14] introduced exponential modulation (IM) into the Delay-Doppler feature of the signal, and the system's BER performance was enhanced by using the Hamming distance optimization model. Zhang et al [15] created a generalized approximated message passing (GAMP) algorithm to estimate underwater acoustic channels in a communication system, which can effectively reduce the computational complexity.…”

Vector Approximate Message Passing Based OFDM-IM Detection for Underwater Acoustic Communications

“…Combining the IM with advanced OFDM schemes, many UWA OFDM-IM transceivers are proposed such as the fully quadrature subcarrier-index shift keying OFDM (FQSISK-OFDM) modulation scheme [13], which put their emphasis on the design of activation strategy. The work [14] combines the IM concept with Orthogonal Time Frequency Space (OTFS) and proposes a Hamming distance optimized model to modify the index combinations. Currently, there is a lack of a design scheme for a lowcomplexity OFDM-IM detector for UWA communications and a detailed analysis of the effects from the UWA channel for UWA OFDM-IM systems.…”