Special issue on S‐band mobile satellite technologies

Abstract

This special issue of the Wiley International Journal of Satellite Communications and Networking hosts a selection of papers related to S-band mobile satellite R&D activities recently completed in the frame of the European Space Agency ARTES programs. The S-band allocation to hybrid satellite and terrestrial services in Europe 2009 and in other parts of the world has attracted operator, industry, and research institution interest for its commercial exploitation. The aim is to illustrate the most recent technical achievements either to improve the S-band satellite system performance or to demonstrate with prototypes the feasibility of new technologies in the user terminal receivers. Dealing with mobile satellite communication services in S-band, the reference air interface for all these scientific papers is the Digital Video Broadcasting - Satellite services to Handhelds (DVB-SH) standard [1], designed to support high-quality broadcasting services over the harsh land mobile satellite (LMS) channel while at the same time able to exploit the presence of terrestrial gap fillers. DVB-SH represents a state-of-the-art air interface for hybrid satellite/terrestrial mobile broadcasting (interactive) networks [2]. In [3], the authors have summarized key findings of an in-depth analysis of the benefits provided by different system architectures and technologies for next generation S-band mobile satellite broadcasting network with interactivity. Along with advanced antenna and payload architectures, a promising way forward in this context is the migration from the conventional single polarization per beam to an advanced dual polarization per beam MIMO architecture for effective spectrum exploitation. In this context, system capacity simulations are showing potential improvements in a 60% to 90% range in terms of overall throughput. Two leading European antenna manufacturers present in [4] and [5] their user terminal antenna prototypes to primarily target professional automotive applications. The main aspects of antenna design are introduced, and the performance of switchable dual polarized vehicular transmit/receive antennas is validated. The form factor of the antenna design described is not only fully in line with typical automotive commercial requirements but also suitable for other markets such as the maritime or the machine-to-machine ones. The aim of [6] is to review the state-of-the-art techniques and architectures supporting beamforming in mobile satellite systems and to evaluate the potential benefits/drawbacks of on-ground beamforming compared to on-board beamforming approach. For this analysis, also some of the beamforming error sources, such as propagation effects at feeder link level, on-board degradations at payload level, differential atmospheric perturbations and Doppler shift effect have been investigated. Finally, a preliminary assessment of the potential advantages given by adopting adaptive beamforming and more advanced on-ground signal processing techniques in multi-spots mobile satellite systems is presented. Stimulated by the large capacity increase potential provided by the dual-polarized S-band satellite systems, the authors in [7] derive a comprehensive MIMO channel model. This paper describes the joint wideband and narrowband modeling approach, provides examples of the usage, and finally describes some evaluation results. This new MIMO model for a dual-polarized LMS-channel environment has been evaluated by comparing the simulated results with data gathered from an extensive field trials carried out within the duration of the project.