20.1 Introduction and Overview

The previous chapter described the history of mobile satellite communications based around the INMARSAT system and its recent privatisation activities. This chapter extends into the new satellite personal communication systems networks using hand-held terminals.

The marketplace which INMARSAT serves today is varied and includes, for example, very large terminals on ships providing primarily compressed voice and so called high-speed data services (64 kbit/s). More recently, with the proliferation of terrestrial cellular systems, the mobile satellite communications marketplace has been demanding smaller terminals with reduced tariffs. This has led to the development of smaller terminals which range from vehicles-mounted (INMARSAT-A analogue, M and B digital) to small hand-portable terminals the size of a laptop computer weighing a few kilograms (INMARSAT mini-M telephone).

The 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...