Network Coding (NC) is a compelling solution for increasing network efficiency. However, it discards corrupted packets and cannot achieve optimal performance in noisy communications. Since most of the information in corrupted packets is error-free, discarding them is not the best strategy. Several packet recovery techniques such as PRAC and S-PRAC were proposed to exploit corrupted packets. Yet, they are slow and only practical when the packet size is small and communication channels are not very noisy. We propose a packet recovery scheme called Fly-PRAC to address these issues. Fly-PRAC exploits algebraic relations between a group of coded packets to estimate their corrupted parts and recovers them. Unlike previous schemes, Fly-PRAC can recover coded packets at the intermediate node without decoding them. We have compared Fly-PRAC against S-PRAC. Results show when the bit error rate (ε) is 10^-4, Fly-PRAC outperforms S-PRAC by two folds for a payload of 900B. In two-hop communication with ε = 10^-4 and a payload size of 500B, by enabling the recovery in the intermediate node, Fly-PRAC reduces transmissions by 16%. In a Sparse Network Coding (SNC) scenario, with two non-zero elements in the coefficient vectors and a payload of 800B, there is a reduction by 31% on average for decoding delay.

翻译：网络编码（Network Coding，NC）是一种提升网络效率的有效方案。然而，它会丢弃受损数据包，因此在有噪通信中无法达到最优性能。由于受损数据包中的大部分信息是无误的，直接丢弃并非最佳策略。已有研究提出了PRAC和S-PRAC等包恢复技术以利用受损数据包，但这些方法速度较慢，且仅在数据包尺寸较小、信道噪声较弱时具有实用性。为解决上述问题，本文提出了一种名为Fly-PRAC的包恢复方案。Fly-PRAC利用一组编码包之间的代数关系来估计其受损部分并进行恢复。与现有方案不同，Fly-PRAC可在中间节点直接恢复编码包而无需进行解码。我们将Fly-PRAC与S-PRAC进行了对比实验。结果表明，在误码率（ε）为10⁻⁴、有效载荷为900B时，Fly-PRAC的性能是S-PRAC的两倍。在ε=10⁻⁴、有效载荷为500B的双跳通信中，通过在中间节点启用恢复机制，Fly-PRAC减少了16%的传输量。在稀疏网络编码（Sparse Network Coding，SNC）场景下，当系数向量包含两个非零元素且有效载荷为800B时，平均解码延迟降低了31%。