奇模排列索引调制的水下光正交时频空技术

Underwater Optical Orthogonal Time Frequency Space Technology with Odd Mode Permutation Index Modulation

摘要:

针对光正交频分复用系统在水下湍流信道中面临的性能恶化问题，引入正交时频空（Orthogonal Time Frequency Space，OTFS）架构在时延-多普勒（DD）域进行信号处理，并采用奇数模式星座设计，提出一种能够有效对抗时变湍流效应，提升频谱效率的奇模排列索引调制（Odd Mode Permutation Index Modulation，OMPIM）技术方案。在详细阐述所提方案的原理后，建立基于伽马-伽马分布的水下湍流信道模型对其进行性能评估。仿真结果表明，在强湍流条件下，OOTFS-OMPIM相比OOFDM-OMPIM在误码率为1×10-4时可获得3-4dB的信噪比增益。所提方案通过DD域信号处理和奇模星座索引设计，有效缓解了湍流引起的信道时变性影响，为实现高速可靠的水下光通信提供了一种可参考的新方案。

Abstract:

To address the performance degradation of optical orthogonal frequency division multiplexing (OFDMA) systems in underwater turbulent channels, an Orthogonal Time Frequency Space (OTFS) architecture is introduced for signal processing in the delay-doppler (DD) domain. Employing an odd-mode constellation design, this paper proposes an Odd Mode Permutation Index Modulation (OMPIM) technique that effectively counters time-varying turbulence effects while enhancing spectral efficiency. enhancing spectral efficiency. Following a detailed explanation of the proposed scheme's principles, a gamma-gamma distribution-based underwater turbulent channel model is established for performance evaluation. Simulation results demonstrate that under strong turbulence conditions, OOTFS-OMPIM achieves a 3-4 dB signal-to-noise ratio gain over OOFDM-OMPIM at a bit error rate of 1×10??. By employing DD-domain signal processing and odd-mode constellation indexing, the proposed scheme effectively mitigates the impact of turbulence-induced channel time-varying effects, offering a novel reference solution for achieving high-speed, reliable underwater optical communication.