Frequency-hopped M-ary frequency-shift-keyed (FH-MFSK) has the ability to handle with long multipath, large Doppler spreads, high ambient noise and rapid phase fluctuation, and is proved to be a robust modulation scheme in mobile shallow underwater acoustic channels. Aiming at this topic, a convolutionally encoded FH-MFSK modulation scheme with a novel iterative multi-channel reception is proposed. To obtain the novel reception suitable for non-coherent M-ary frequency-shift-keyed, the ideas of iterative multi-channel demodulation and decoding are combined and extended. A modified multi-channel soft-input–soft-output demodulator based on maximum-a-posterior criterion is derived, and substantial gains of several decibels in power efficiency are achieved. Extra gain can be obtained by utilising time diversity with long multipath delay. Simulation shows that a non-coherent receiver equipped with five arrays obtains around 5.5 dB gain over the single non-iterative receiver. A shallow water field testing at Songhua Lake with 300 m distance confirms that the proposed receiver verifies its robustness and usability.

中文翻译：

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水下浅水声通道中的迭代多通道FH-MFSK接收

跳频M进制频移键控（FH-MFSK）具有处理多径长，多普勒扩展大，环境噪声高和相位波动快的能力，并被证明是一种在浅水移动水下运动中的鲁棒调制方案声音通道。针对这一主题，提出了一种具有新颖的迭代多信道接收的卷积编码FH-MFSK调制方案。为了获得适用于非相干Mary频移键控的新颖接收方式，将迭代多通道解调和解码的思想进行了组合和扩展。推导了一种改进的基于后验最大准则的多通道软输入软输出解调器，并在功率效率上获得了几分贝的实质性收益。通过利用具有长的多径延迟的时间分集可以获得额外的增益。仿真表明，配备有五个阵列的非相干接收机在单个非迭代接收机上可获得约5.5 dB的增益。在距离松花湖300 m处的浅水场测试中，证实了所提出的接收器验证了其坚固性和可用性。