Fabrice Arnal

Combining Adaptive Coding and Modulation With Hierarchical Modulation in Satcom Systems

We investigate the design of a broadcast system in order to maximize throughput. This task is usually challenging due to channel variability. Forty years ago, Cover introduced and compared two schemes: time sharing and superposition coding. Even if the second scheme was proved to be optimal for some channels, modern satellite communications systems such as DVB-SH and DVB-S2 rely mainly on a time sharing strategy to optimize the throughput. They consider hierarchical modulation, a practical implementation of superposition coding, but only for unequal error protection or backward compatibility purposes. In this article, we propose to combine time sharing and hierarchical modulation together and show how this scheme can improve the performance in terms of available rate. We introduce a hierarchical 16-APSK to boost the performance of the DVB-S2 standard. We also evaluate various strategies to group the receivers in pairs when using hierarchical modulation. Finally, we show in a realistic case, based on DVB-S2, that the combined scheme can provide throughput gains greater than 10% compared to the best time sharing strategy.

Generic approach for hierarchical modulation performance analysis: Application to DVB-SH

Broadcasting systems have to deal with channel diversity in order to offer the best rate to the users. Hierarchical modulation is a practical solution to provide several rates in function of the channel quality. Unfortunately the performance evaluation of such modulations requires time consuming simulations. We propose in this paper a novel approach based on the channel capacity to avoid these simulations. The method allows to study the performance in terms of spectrum efficiency of hierarchical and also classical modulations combined with error correcting codes. Our method will be applied to the DVB-SH standard which considers hierarchical modulation as an optional feature.

IP Mobility and Its Impact on Satellite Networking

With the advent of new generation of wireless networks (3G and beyond) and the convergence of network technologies and services around IP, mobility is about to be a common feature integrated in all future networks. In GEO satellite networking, the deployment of Mobile IP raises some important issues that need to be addressed. This paper aims to pinpoint the impact of mobility in a satellite system with other key network features - namely QoS, multicast, and the specific issue of TCP acceleration with PEPs. Some candidate solutions based on the Mobile IP v6 framework and extensions are proposed and analyzed.

Architecture of an IP-based aeronautical network

The International Civil Aviation Organization (ICAO) has defined a mobile IPv6-based Aeronautical Telecommunications Network (ATN/IPS) as a next generation communication network for future Air Traffic Management (ATM). The ATN/IPS will be used with different terrestrial and satellite link technologies for supporting future ATM. In parallel, non-operational services will use different link technologies as well. In such an environment, the main challenge is to design a network architecture that integrates all link technologies in a way that mobile users (be it a cockpit user or a passenger) can make use of them in a seamless way. This paper presents the core functionalities developed within the NEWSKY project of such an integrated IP network architecture.

Cross-layer reliability management for multicast over satellite

Multicast services are well supported by geostationary satellites as a result of their broadcasting capability over large coverage areas. However, in this context the reliability management must be accurately analysed, since satellite resources are expensive and link quality degrades significantly during adverse weather conditions. In this paper, we show that the conventional layered approach of reliability management can be adapted and optimized for multicast over satellite. Our proposal consists in removing, at low layers, most of packet discardings, and introduces the MPHP mechanism which protects protocol headers. At transport level, for full reliability, we adapt conventional erasure decoding used with packet-level FEC and on this basis we propose a hybrid-ARQ protocol with a specific error and erasure decoding. The performance analysis shows that applications like real-time multimedia delivery using UDP-lite for partial reliability can benefit from a reduced error rate, and applications like massive file transfers requiring full reliability are less demanding in terms of network resources.

Overview of Platine emulation testbed and its utilization to support DVB-RCS/S2 evolutions

Designing new satellite access protocols or validating innovative satellite network concepts, evaluating their performances and demonstrating them require powerful test tools to check their compliance with satellite system requirements. Obviously, such tools have to be as representative as possible of typical satellite telecom systems, but also adaptable to specific research and engineering needs. Emulation testbeds provide a cost effective solution for networking activities in complement to traditional simulations tools that are rather suited in satcom research to system dimensioning evaluation. This paper presents the Platine emulation, briefly presents major projects where is has been used, and details its architecture and main features as well as its controller unit. Finally, future perspectives are stressed, for example in the aeronautical communication context.

Minimizing end-to-end delay in global haha networks considering aeronautical scenarios

The International Civil Aviation Organization (ICAO) has recently standardized the IP-based aeronautical telecommunication network (ATN/IP) as a next generation communication network for the aviation industry. ATN/IP considers Mobile IPv6 (MIPv6) as a basic mobility protocol which only provides host mobility. However, considering large number of hosts within an aircraft, there is a need for network mobility (NEMO). IETF has already specified a NEMO protocol that introduces a new entity called Mobile Router (MR) in order to perform mobility signalling for all Mobile Network Nodes (MNNs) connected to the MR. However, the base NEMO protocol does not support route optimization (RO), a feature which provides better end-to-end delay performance. Up to now, different RO methods are proposed for NEMO in IETF and in this paper, we consider Global Home Agent to Home Agent (Global HAHA) as a NEMO RO solution in aeronautical environment and propose a new home agent selection method in order to minimize end-to-end delay in this network.

Satellite-Terrestrial Integration Scenarios for Future Information-Centric Networks

This paper addresses scenarios of integrated satellite-terrestrial Future Internet networks based on the Information-Centric Networking (ICN) communication paradigm. Focus is given on three integration scenarios: i) Hybrid Broadcast IPTV, paving the way for SatCom integration within the Future Media Internet; ii) Smart M2M Transport, paving the way for SatCom integration within a future Internet of Things; and iii) Extended 4G Backhauling, paving the way for SatCom integration within the 4G mobile Internet.

SatERN: A PEP-Less Solution for Satellite Communications

In networks with very large delay like satellite IP-based networks, standard TCP is unable to correctly grab the available resource. To overcome this problem, Performance Enhancing Proxies (PEPs), which break the end-to-end connection and simulate a receiver close enough to the sender, can be placed before the links with large delay. Although splitting PEPs does not modify the transport protocol at the end nodes, they prevent the use of security protocols such as IPsec. In this paper, we propose solutions to replace the use of PEPs named SatERN. This proposal, based on Explicit Rate Notification (ERN) protocols over IP, does not split connections and is compliant with IP-in-IP tunneling solutions. Finally, we show that the SatERN solution achieves high satellite link utilization and fairness of the satellite traffic.

NEMO route optimization solution space analysis and evaluation criteria for aviation

The aviation community is currently designing an IPv6-based aeronautical telecommunication network (ATN/IP), which aims to provide seamless communication services to the cockpit users. One of the challenging tasks in the ATN/IP is the scalable mobility management of aircraft as entire networks in motion. We have investigated possible IPv6-based network mobility (NEMO) route optimization (RO) solutions for safety related and non-safety related services. We have also presented realistic ATN/IP topology and a set of evaluation criteria for a better analysis of the possible solutions. Our investigations showed that MR-based RO solutions are more suited than MNN-based RO solutions to the aeronautical environment for the near future. We have also realized that multiple MR-based RO solutions could also be used together for a better end-toend route optimization.