onfusing marketplace. As is typical when one technology is replacing another, caution prevailed, and customers responded with the need to know who stood behind the name.
The emergence of more caution on the part of the consumer coincided with AT&T Wireless' emergence as a national presence after its 1996 launch of digital service in 40 metropolitan markets. While not a PCS provider by definition, masterfully marketing the enhanced capabilities of its digital cellular technology, dubbed "Digital PCS," positioned AT&T Wireless as a key player in the evolving wireless industry.
Traditionally, until the last few years, all satellites used geo stationary orbits. Their main advantage was that they required the fewest number of satellites in their constellation. The downside was that propagation delays were lengthy, reaching 250 to 270 msec.
A new kind of satellite, a LEO (low-earth orbiting) operates in a non-geo stationary orbit, which is at a lower altitude than other satellites. As a result, the transmission time between two earth stations is shortened, which reduces or virtually eliminates the time delay present in current satellite systems.
The LEO market contains three primary divisions:
Big LEOs--These are built by companies that provide voice and data services, such as AT & T
Little LEOS-- Smaller and just capable of offering dats and location positioning services.
Mega LEOS--These are built by the gigantic companies, such as Teledesic (owned in part by Bill Gates and Microsoft) that are looking to build an Internet in the sky.
Comparing these satellite systems with cellular, fiber-based or other existing telecommunications solutions, there are many advantages. These advantages "include global coverage, lower propagation delay, higher bandwidth, low error rates and system architecture interoperability" (Arends, 1997, 4).
So it is safe to say that LEO is the spine or b
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