| Popis: |
Transportable troposcatter systems are a valid beyond line-of-sight transmission medium in support of NATO Expeditionary Operations, particularly in providing augmentation and/or alternative in-theatre links between deployed headquarters. In cooperation with industry, NATO Communications and Information Agency (NCI Agency) has been conducting research and experimentation in highly deployable troposcatter systems. This activity has validated the suitability of these systems for military applications but also put in evidence the significant dependence of the performance of a given BLOS link with the applicable climate zone. In 2012, the Radiocommunication Bureau of the ITU (ITU-R) simultaneously issued a new version of the P.617 Recommendation (P.617-2) and a new recommendation, P.2001. Recommendation P.617-2 provides, inter alia, a reclassification of the climate zones applicable to troposcatter propagation analyses and, most notably and for the first time, a world map defining the geographical application of the various climate zones. P.2001 offers a general-purpose wide-range terrestrial propagation model in the frequency range 30 MHz to 50 GHz, with a troposcatter sub-method. This paper provides a comparative analysis of the new troposcatter propagation model and methods with the ones previously available. It then presents a theoretical geographical analysis of expected troposcatter link performance using previously identified reference troposcatter links and commercial implementations of deployable troposcatter systems. This paper provides the military communications community with an analysis of the new troposcatter model and a long-awaited geographical distribution of troposcatter link performance. |
