IJSC&N Special Issue “network coding applications in satellite networks”: Guest editorial message
Giovanni Giambene, Nader S. Alagha · International Journal of Satellite Communications and Networking · 2017
In contrast to conventional point-to-point transmission, where only data sources can send encoded packets, network coding allows intermediate nodes in a network to (re-)encode packets before sending them instead of adopting a simple store-and-forward routing approach. It has been shown that network coding can provide many advantages in correcting random packet erasures and in improving the performance of reliable multicast schemes. The advantages are significant in error-prone scenarios like those with mobile users. The Internet Research Task Force (IRTF) has approved the Network Coding Research Group (NWCRG), considering important aspects concerning the adoption of network coding, such as architectural issues, end-to-end versus hop-by-hop network coding, inter-flow network coding (at OSI layer 3 or layer 2) versus intra-flow, application-layer network coding, security issues and robustness to attacks, packet formats, and proactive protection with network coding versus reactive mechanisms based on classical ARQ schemes. The aim of this special issue of IJSC&N has been to shed light on potential applications of network coding and achievable performance gains particularly in satellite communication networks. Network coding represents a powerful approach to protect data from losses due to link disconnections and can also allow exploitation of the combination of multiple paths to deliver data to users (eg, multicast applications, smart gateway diversity techniques, hybrid network scenarios, etc.) with the possibility of recoding at intermediate nodes. Importantly, network coding can be applied at different OSI layers in the context of satellite networking, and this aspect is the subject of current investigations to understand where it is more convenient to apply network coding. This special issue brings together 2 papers coming from ESA's SatNEx IV research activities on “Network Coding Applications in Satellite Communications Networks” along with 3 additional papers written by experts in this field in order to cover various aspects of network coding adoption in satellite networks. This issue starts with a paper entitled “Physical Layer Aware Adaptive Network Coding Schemes for Satellite Communications” (authors: S. A. M. Ghanem, A. E. Gharsellaoui, D. Tarchi, and A. Vanelli Coralli), dealing with rate efficient and energy efficient adaptive Random Linear Network Coding (RLNC) schemes for land mobile satellite systems in a time-varying channel. By means of physical layer awareness, the proposed schemes compensate for packet losses by tracking the packet erasures over time. The authors shed light on the tradeoff between energy efficiency and delay-throughput gains, demonstrating that conservative adaptive approaches might cause higher delays and lower throughput gains in comparison with non-conservative approaches that favor transmissions. The second paper, entitled “Network Coding for System-level Throughput Improvement in Satellite Systems” (authors: R. Alegre-Godoy and M. Á. Vázquez-Castro), investigates 2 scenarios for network coding applicability. In the first case, a network coding-based multicast scheme is considered that achieves high multicast throughput gains. Under the assumption that user terminals (UTs) are able to simultaneously receive multiple transmissions, the authors show a significant increase in the throughput. A second scenario exploits both diversity and interflow network coding to overcome severe packet losses in a number of scenarios where no channel state information is available. The system outage probability can be reduced, and the throughput can be improved by means of network coding. The third paper, entitled “Implementation and Experimentation of Network Coding in DVB-S2/RCS2 Systems” (authors: S. Erl, T. de Cola), deals with the application of network coding to satellite networks exploiting the DVB-S2/RCS2 air interfaces. The work bridges the gap on network coding implementation in real satellite systems. In particular, this paper extends the DVB-S2/RCS2 architecture to support network coding functions, operating between network and datalink layers. Performance analysis results demonstrate the effectiveness of the proposed integrated architecture. The fourth paper, entitled “Transport Layer Performance Combining Multipath and Network Coding in Mobile Satellite Networks” (authors: G. Giambene, D. K. Luong, V. A. Le, T. de Cola and M. Muhammad), considers future satellite networks able to exploit multiple paths to reach mobile users. The interest is to exploit the path diversity by adopting network coding across multiple paths at a shim layer between IP and MAC layers. Path-based network coding (PBNC) techniques have been combined with multipath-TCP (MPTCP) and TCP at transport layer. Simulation results show that PBNC techniques can improve the aggregated transport-layer goodput with respect to a 2-path benchmark network coding scheme. Finally, the fifth paper, entitled “RLNC in Satellite Networks: A Cooperative Scenario for Delivering M2M Traffic” (authors: M. Bacco, A. Gotta) investigates the use of RLNC techniques in land mobile satellite channels to reliably deliver M2M traffic to mobile nodes in urban areas for vehicular applications. It is considered that mobile nodes can cooperate by relying on RLNC gossiping algorithms where the incoming information flow is re-encoded before delivering to neighboring vehicular users. The results show that the use of RLNC-based gossiping can remove the need for any fixed equipment on the ground (road unit) to repeat the signal received from the satellite. In closing this editorial message, we would like to thank all the authors for their excellent contributions. We also thank the reviewers for their valuable comments and suggestions in refining the quality of the papers. We appreciate Professor Barry Evans for his interest on this topic and his timely support. Finally, we hope that the readership will find this special issue interesting. Giovanni Giambene([email protected]): Giovanni Giambene was born in Florence, Italy, in 1966. He received the Dr. Ing. degree in Electronics in 1993 and the Ph.D. degree in Telecommunications and Informatics in 1997, both from the University of Florence, Italy. From 1994 to 1997, he was with the Electronic Engineering Department of the University of Florence, Italy. He was Technical External Secretary of the European Community COST 227 Action (“Integrated Space/Terrestrial Mobile Networks”). He also contributed to the SAINT Project (“Satellite Integration in the Future Mobile Network”, RACE 2117). From 1997 to 1998, he was with OTE (Marconi Group) in Florence, Italy, working on a GSM development program. In 1999, he joined the Department of Information Engineering and Mathematical Sciences of the University of Siena, Italy. At present, he is associate professor, teaching the first-level course on Fundamentals on Telecommunications and the advanced course on Networking at the University of Siena. From 2000 to 2003, he contributed to the EU FP5 “Personalised Access to Local Information and services for tourists” (PALIO) IST Project. He was vice-Chair of the COST 290 Action (2004-2008), entitled “Traffic and QoS Management in Wireless Multimedia Networks” (Wi-QoST). He participated to: (i) the SatNEx I & II network of excellence (EU FP6, 2004-2009) and SatNEx III (ESA 2010-2013) as work package leader on radio access techniques, cross-layer air interface design, and network coding techniques for satellite systems; (ii) the EU FP7 Coordination Action “Road mapping technology for enhancing security to protect medical & genetic data” (RADICAL) as work package leader on security and privacy; (iii) the COST Action IC0906 (2010-2014) “Wireless Networking for Moving Objects” (WiNeMO) as national representative; (iv) EU FP7 Coordination Action RESPONSIBILITY. At present, he is involved in the ESA SatNEX IV project. Giambene is IEEE senior member. From October 2011 to December 2015, he was IEEE Communications Letters associate editor. Since March 2015 he is editor of IEEE Transactions on Vehicular Technology. He has published the following books: G. Giambene, “Queuing Theory and Telecommunications: Networks and Telecommunications”, Springer, April 2014 (2nd edition); G. Giambene (Ed.), “Resource Management in Satellite Networks: Optimization and Cross-Layer Design”, Springer, April 2007. His research interests deal with wireless and satellite networking, cross-layer air interface design, transport layer performance, privacy and security. Nader Alagha ([email protected]): received his Ph.D. Degree in Electrical and Computer Engineering from McGill University, Montreal, Canada. In 1999 he joined Space and Technology group at EMS Technologies Canada. From 2004 to 2006 he was a Senior Member of Technical Staff at Advantech Satellite Networks where he was involved in R&D projects related to the interactive satellite networks. Since 2006 he has been with the Electrical Engineering Department of the Technical Directorate at European Space Agency Research and Technology Centre (ESTEC) in The Netherlands. He has been the technical lead of several R&D projects related to broadband satellite system and VHF maritime communications as well as ESA research studies of satellite network of experts (SatNEx IV). He has contributed to several standardization technical groups including DVB-S2X and DVB-RCS2. Dr. Alagha is an executive committee member of the IEEE Benelux Chapter on Communications and Vehicular Technology. He has also been a member of Technical Program Committee of several international conferences including the IEEE GLOBECOM 2016.