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.

Floods are major natural disasters which cause deaths and material damages every year. Monitoring these events is crucial in order to reduce both the affected people and the economic losses. In this work we train and test three different Deep Learning segmentation algorithms to estimate the water area from river images, and compare their performances. We discuss the implementation of a novel data chain aimed to monitor river water levels by automatically process data collected from surveillance cameras, and to give alerts in case of high increases of the water level or flooding. We also create and openly publish the first image dataset for river water segmentation.

This paper proposes a novel method to optimize bandwidth usage for object detection in critical communication scenarios. We develop two operating models of active information seeking. The first model identifies promising regions in low resolution imagery and progressively requests higher resolution regions on which to perform recognition of higher semantic quality. The second model identifies promising regions in low resolution imagery while simultaneously predicting the approximate location of the object of higher semantic quality. From this general framework, we develop a car recognition system via identification of its license plate and evaluate the performance of both models on a car dataset that we introduce. Results are compared with traditional JPEG compression and demonstrate that our system saves up to one order of magnitude of bandwidth while sacrificing little in terms of recognition performance.

Following decades of closed proprietary satellite systems, the open European Telecommunications Standards Institute (ETSI) standard for interactive broadband satellite services digital video broadcast-return channel via satellite (DVB-RCS) was approved and published in March 2000. Considerable work has been performed by satellite operators, manufacturers and others, in order to deploy DVB-RCS systems for commercial Internet protocol (IP) services. Their efforts have not only resulted in several DVB-RCS systems now in commercial operation, but also in a common focus on interoperability between equipment from different manufacturers through the SatLabs group, working under the auspices of the European Space Agency (ESA). In addition to the open standard aspect, success for DVB-RCS depends on equipment cost and bandwidth efficiency offered by the system, as discussed in this paper. Equipment cost is important as it represents the initial investment for the operator and the final users, while the cost of usage depends on the efficiency, and will, in the long term, be the dominating cost factor. The DVB-RCS specification opens up for a wide range of radio resource management (RRM) implementation possibilities and the RRM plays a key role in optimizing the efficiency of the system for the targeted IP services. This paper presents the main features of a complete DVB-RCS system, the Nera SatLink system, hereafter only referred to as the SatLink system, and offers measurement results and experience from DVB-RCS installations. Critical parts of the system are highlighted, and focus is given to the objectives for current optimization of the system.

The European Telecommunications Standards Institute, ETSI, is working on standards for future broadband satellite systems. This paper offers an overview of the ETSI work, relates it to other important work by organizations such as the DVB Project, ITU and IETF, and discusses the potential application areas.

Line spectral pairs (LSP) are, because of their advantageous properties, commonly used to represent the spectral information in a linear predictive (LP) speech coder. However, the quantised spectrum is relatively sensitive to channel errors. This paper describes a robust quantiser for LSPs transmitted over noisy waveform channels, based on an optimisation of the source coder over the modulation scheme. Modulation organized vector quantisation, MOR-VQ, jointly optimises a codebook and its index assignment, governed by the defined modulation symbol constellation. The system closely follows the optimum performance theoretically available (OPTA). Moreover, the MOR-VQ scheme allows for efficient codebook search strategies.>