Satellite Communications

We are delighted to bring to you this special issue on satellite communications, which we have prepared as part of the spreading of excellence remit of the satellite communications network of excellence (SatNEx). The SatNEx project, which began in 2004, is funded for five years under the Euro-pean Union's Sixth Framework Programme (FP6) Information Society Technologies (IST) Thematic Area. Led by the German Aerospace Center, SatNEx brings together a network of 24 partners, distributed throughout Europe, with membership drawn from ten countries. The philosophy underlying the SatNEx approach revolves around the selection of focused actions under Joint Programmes of Activities, which are carried out collectively by the partners and include research, integration, and dissemination activities. Training represents an important part of the SatNEx remit and is supported through a number of initiatives including the hosting of internship projects and an annual summer school. The call for papers resulted in a high number of submissions , from which we have been able to select 12 excellent papers dealing with the different aspects of satellite communications and navigation. Multiple-input multiple-output (MIMO) techniques are attracting a considerable amount of attention from within the terrestrial wireless community. The first paper of this special issue, " Multisatellite MIMO communications at Ku band and above: investigations on spatial multiplexing for capacity improvement and selection diversity for interference mit-igation, " considers the application of such technology over a satellite platform operating in the Ku band and above. The paper considers how MIMO can be used to increase capacity by using a satellite spatial multiplexing system and how antenna selection can be used to mitigate interference. The next paper " Investigations in satellite MIMO channel model-ing: accent on polarization " looks at MIMO systems from the polarization diversity point of view and dwells on the satellite cooperative communication concepts. Switch and stay combining (SSC) is a form of diversity technique used in digital receivers to compensate for fade events introduced by the mobile channel. The third paper " Performance analysis of SSC diversity receivers over correlated Ricean fading satellite channels " investigates the performance of dual-branch SSC receivers for different fading channel characteristics. The next four papers deal with the emerging scenario of mobile digital video broadcasting (DVB-S2 and RCS mobile). Alternative approaches to counteracting fading channels introduced when operating in a train environment receiving satellite DVB-S2 are presented in the paper " Advanced fade countermeasures for DVB-S2 …