1、QUESTION ITU-R 87-4/4, *Transmission characteristics for a mobile-satellite communication system (1988-1990-1992-1993-2007) The ITU Radiocommunication Assembly, considering a) that currently the International Maritime Organization (IMO) has recognized only one provider of mobile-satellite communicat
2、ions (Inmarsat) for the GMDSS; b) that other organizations offer or plan to offer international or domestic mobile-satellite services; c) that modulation techniques and systems should be robust under fading and shadowing conditions; d) that the efficiency of orbit-spectrum utilization in mobile-sate
3、llite systems will be determined in part by the technical characteristics employed, such as modulation methods and parameters, impact of frequency reuse techniques or the arrangement of radio-frequency carriers, decides that the following Question should be studied 1 What are the preferred transmiss
4、ion characteristics for the following systems: 1.1 land mobile-satellite systems; 1.2 maritime mobile-satellite systems, including GMDSS; 1.3 aeronautical mobile-satellite systems; 1.4 mobile-satellite systems incorporating a combination of two or more of the above systems? 2 What are the technicall
5、y preferred multiple access, modulation and coding methods for such systems? 3 What are the preferred performance characteristics of earth stations and space stations for such systems? 4 What transmission characteristics could be common to facilitate compatibility between the land, maritime, and aer
6、onautical mobile-satellite services? further decides 1 that the results of the above studies should be included in one or more Recommendation(s); 2 that the above studies should be completed by 2007. Category: S2 _ This Question should be brought to the attention of the International Maritime Organization (IMO). *Former Question ITU-R 87-4/8.
