Guest Editorial: IJSCN Special Issue on ASMS/SPSC 2012

This Special Issue of theWiley International Journal of Satellite Communications and Networking hosts a selection of papers from the 6 Advanced Satellite Multimedia Systems (ASMS) Conference and the 12 Signal Processing for Space Communications (SPSC) Workshop, held in Baiona, Spain on September 5-7, 2012. The joint event was organized through a collaborative effort of the University of Bologna, the Institute of Communications and Navigation of DLR (German Aerospace Center), the European Space Agency (ESA), under the auspices of the ISI (Integral SatCom Initiative) European Technology Platform and the SatNEx III Network of Experts and in cooperation with the University of Vigo. The ASMS conference and SPSC workshop have become recognized events for industry and research institutions to exchange up-to-date information about recent advances and emerging technologies in the field of mobile satellite communication systems. The ESA’s SPSC workshop dates back to1988 when pioneering work in digital signal processing for satellite communications was first presented by worldwide authorities in the field. In addition, following the successful path opened by the 2006 edition of ASMS and continued with the 2008 and 2010 editions, the scope of the conference has been further widened, as the small though important change in its name by replacing the word “mobile”with “multimedia” testifies. This is remarkable not only because the major part of the satcom market belongs to broadcasting and broadband access operators, but fundamentally because the convergence of broadcast, mobile and fixed satellite communications is essential to offer seamless connectivity anywhere at anytime, which is recognized as the key element for the successful deployment of future satellite systems. This Issue collects the extended versions of five of the best papers presented at the last ASMS/SPSC joint event. The papers have been selected with the aim of providing an insight in the developments and findings in this exciting field. In the first paper, the authors review the main information-theoretic results on channels affected by a time-varying phase noise and presents MAP symbol detection algorithms to be employed in such a challenging scenario considering linear modulations and advanced coding schemes based on iterative detection and decoding. The second paper outlines the scenario of the expected atmospheric impairment affecting a satellite radio link operating in the W band, as derived by the present theoretical and experimental knowledge. W-band is the next candidate after Q/V-band for high throughput feeder links between satellite and Earth. The paper discusses the contributions to signal fade due to gases, clouds, scintillation and rain as well as to the depolarization of the electromagnetic waves. The third paper extends the analysis conducted in previous studies towards non-binary LDPC codes for deep-space missions getting even closer to the ultimate Shannon capacity. Performance assessment is carried out with respect to reliability metrics and encoding/decoding complexity. Finally, the integration of erasure codes into the CCSDS protocol stack is also discussed. The fourth paper analyses Orthogonal Frequency-Division Multiple Access (OFDMA) and SingleCarrier Frequency Division Multiple Access (SC-FDMA) for satellite uplink. Both schemes provide a higher spectral efficiency than conventional single-carrier modulation schemes, but are unfortunately more vulnerable at a different level to nonlinear distortion, phase noise, and synchronization errors. The fifth paper investigates a novel collision recovery scheme for symbol-synchronous slotted ALOHA (SA) based on physical layer network coding over extended Galois fields. A performance evaluation is carried out using the proposed algorithms, revealing interesting performance in terms of normalized throughput and energy efficiency. Results are compared to other known high performance slotted random access schemes.