New challenges to mobile satellite communications have really come from the terrestrial cellular industry where small terminals have found very widespread use. The growth in the deployment of cellular telephony systems in the 1980s and 1990s has been phenomenal and this has led to massive reductions in the cost of terminals and call charges together with the offering of a wide range of services. With cellular telephony, a ground-based technology, it became apparent that industry was willing to deploy these systems only where there were sufficient numbers of subscribers, i.e. the densely populated areas - urban and suburban only. This would therefore leave out large geographical areas where the offering of cellular telephony would not be economical owing to coverage and mobility issues. This is the niche market which mobile satellite communications has come to fill. Therefore, mobile satellite communication systems tend to complement cellular systems by providing services in difficult areas. It is also possible that satellite communications may even eventually compete with cellular systems if the costs can be reduced significantly - at this stage a daunting task. The trend for the next-generation mobile systems - those referred to as the third-generation systems-is to provide seamless communication services to users wherever they are with a single multimode terminal and a single user number. This is the domain of personal communication services/ networks (PCS/PCN) and satellite PCN for the systems being planned will be an inherent component of global PCN.
Satellite personal communication networks, Page 1 of 2
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