Online fountain codes (OFCs) have many advantages, such as low overhead, online feedback and optimal encoding, due to the feedback of the instantaneous decoding state. This paper analyzes the characteristics of underwater acoustic networks (UANs) as well as the issues of existing OFCs applied in UANs. Aiming at these issues, two optimization objectives of OFCs are put forward for UANs. In addition, a recursive OFC with limited feedback (ROFC-LF) is presented for UANs. The ROFC-LF reduces the consumption of bandwidth and energy caused by the transmission of useless coding packets. Through limited feedback, the problem of low channel utilization in UANs with half-duplex communication is solved. Furthermore, a data transmission mechanism based on the ROFC-LF for UANs is presented. The theoretical analysis and simulation results show that the proposed transmission mechanism based on the ROFC-LF scheme outperforms the existing OFC schemes in terms of overhead, computational complexity, coding efficiency and energy consumption. Consequently, the ROFC-LF is suitable for UANs with constrained resources.

中文翻译：

---

ROFC-LF：水下声学网络反馈有限的递归在线喷泉代码


由于瞬时解码状态的反馈，在线喷泉码（OFC）具有许多优点，例如低开销、在线反馈和最优编码。本文分析了水声网络（UAN）的特点以及现有OFC在UAN中应用的问题。针对这些问题，针对UAN提出了OFC的两个优化目标。此外，还为 UAN 提出了一种具有有限反馈的递归 OFC（ROFC-LF）。 ROFC-LF减少了无用编码包传输带来的带宽和能量消耗。通过有限反馈，解决了半双工通信UAN中信道利用率低的问题。此外，还提出了一种基于ROFC-LF的UAN数据传输机制。理论分析和仿真结果表明，所提出的基于ROFC-LF方案的传输机制在开销、计算复杂度、编码效率和能耗方面优于现有的OFC方案。因此，ROFC-LF适合资源有限的UAN。