The ITU Radiocommunication Assembly considering a) that currently the International Maritime Organization (IMO) has recognized only one provider of mobile-satellite communications (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-satellite 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.