Early Efforts

Nov 09,2011 00:00 by alperen
Motorola proposed what turned out to be a rather overambitious project known as Iridium. Other vendor consortia, which included companies like Hughes and Raytheon with space sector experience, proposed similar projects. After a number of years, spectrum was allocated, and after a number of years, systems were built. In the meantime, terrestrial networks—first and second generation—had extended their geographic coverage in many countries to 80 percent, 90 percent, or in some countries, over 90 percent, and by implication, greatly reduced the geographic addressable market for satellite-based services. In urban areas, satellite-based systems did not work very well because of building blocking. You needed to go outside to make your phone work. The solution was to produce dual-mode phones giving satellite access and cellular access, but this made the phones rather large and expensive. These were the main technical reasons why the satellite-based systems (initially Iridium and Globalstar) failed commercially. There were also many marketing and business reasons for their failure, but these are outside the scope of this book. However, many valuable lessons have been learned from the deployment experience to date. It is quite rational to expect that satellite-based systems will play a significant role in fourth-generation cellular service provision, so it is well worth reviewing present and likely future technology options. 376