Pre-Decoding Recovery Mechanism for Network Coding Opportunistic Routing in Delay Tolerant Networks

Network coding opportunistic routing (NCOR) offers a promising solution for efficient data transmission in delay tolerant networks. Due to the multi-copy strategy and network coding nature, NCOR inevitably brings about a large number of heterogeneous copies, leading to over-consumption of limited network resources. To alleviate this situation, it is imperative to study how to reduce redundant copies in the network. In this paper, we propose a pre-decoding recovery mechanism (PDRM) that removes residual copies after the destination node obtains the original packet information. The PDRM consists of three operations: generating pre-decoding elements, maintaining immune-lists, and deleting redundant copies. In particular, the destination node generates a pre-decoding element, and then, sends it to other nodes in the network via an immune-list to help remove the residual copies. Here, the pre-decoding element is an acknowledgement indicating that the destination node has the necessary information to decode the corresponding original packet. As the core of the PDRM, the first operation enables the destination node to generate a pre-decoding element for each innovative packet without waiting for decoding the generation. Simulation results demonstrate that the PDRM achieves excellent results in improving network performance, and outperforms the existing recovery mechanism.