SatNetCode: Functional Design and Experimental Validation of Network Coding over Satellite

In this paper, we present the functional design and experimental validation of network coding technology over hybrid networks including satellite links. We first describe our design framework based on a holistic modelling of (overlay) heterogeneous networking satellite scenarios. We then define different types of logical nodes depending on their encoding, re-encoding and decoding functionalities and whether or not the satellite (overlay) application designer has control over them. Nodes are assumed strategically chosen to recode, which may result in a small number of re-encoding nodes that suffice to optimize selected performance metrics. Our main contribution is a system-oriented functional design of network coding that enables flexible instantiation of different types of network codes via configurable network coding (C-NC) functions. Random or structured NC coefficients can be remotely or locally generated and a packet scheduler can forward packets according to different policies. The choice of coefficients and overall NC scheme depend on the SATCOM-specific performance target, namely delay or bandwidth constraints. Here, we present a preliminary design and experimental testebed validation for the case of delay constrained transmission. Our results show the practical benefits of re-encoding and performance tradeoffs of different network coding schemes. In particular, our results show the good structural properties and delay-reliability tradeoffs of our novel proposal of structured network codes using Pascal matrices due to the regenerative properties of the coding coefficients.