On the Performance of Erasure Coding over Space DTNs

Erasure coding has attracted the attention of space research community due to its potential to present an alternative or complementary solution to ARQ schemes. Typically, erasure coding can enhance reliability and decrease delivery latency when long delays render ARQ-based solutions inefficient. In this paper, we explore the benefits of erasure coding for file transfers over space Delay Tolerant Networks, using a generic end-to-end mechanism built on top of the Bundle Protocol that incorporates LDPC codes along with an ARQ scheme. The results reveal significant insights on the tradeoff among efficient bandwidth exploitation and delivery latency. We quantify the performance gains when optimal erasure coding is applied and investigate in what extent theoretically optimal performance is affected when suboptimal code rates are used. Beyond that, we highlight the ability of erasure coding to provide different QoS to applications, in terms of file delivery latency, by properly tuning the code rate.