Speech compression algorithms in mobile satellite systems

Development of modern satellite systems goes from the existing land-mobile systems (such as INMARSAT-M, INMARSAT-"mini-M", AMSC/TMI, OPTUS) towards truly mobile near-future systems (such as IRIDIUM, GLOBALSTAR, ICO, ACeS, Thuraya). Upcoming systems represent the personal communication systems with handheld terminals similar to the cellular mobile phones. One of the key technologies that enables this evolution is a design of the very low-bit rate speech compression algorithms providing a robust high-quality synthesized speech with a relative low delay. In most of the mentioned systems speech compression solutions based on the multi-band excitation (MBE) technology are used. In fact, this paper is dedicated to the overview of basic characteristics of the modern mobile satellite system with a special emphasis on the use of low-bit rate speech compression algorithms.