Iridium Case Study Essay

2238 Words Jun 22nd, 2016 9 Pages
Iridium, a 485 miles view
The name Iridium is derived from the chemical element “Iridium” which has an atomic number of 77. The original architecture of Iridium had 77 satellites, but later the altitude was raised, leading to a 66-satellite constellation(1). 1) What were some of the problems of mobile phone services during the 1990s?
In early 1990’s with the use of digital voice coding and digital modulation, the 2G - Global System for Mobile communication (GSM), technology was introduced and some limitations of 1G were addressed. GSM increased bandwidth, allowing addition of more customers, and the rapid increase in customer base was not followed by a rapid increase in cell sites (towers) to provide better signal quality to expand
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3) What are the advantages and disadvantages of LEO compared with GEO? * GEO has lifespan greater than 15 years. LEO lifespan is between 5 to 7.5 years * GEO orbiting distance is greater than LEO orbiting distance, causing weaker signal than LEO signal strength * GEO is more economical because the costly launch of new LEO satellite every 5 years * Twice a year the sun crosses behind each GEO satellite as it is viewed from the ground station causing a temporary loss of signal due to the thermal noise from the sun with the satellite (5) * signals causes a temporary loss of signal * GEO has lifespan greater than 15 years. LEO lifespan is between 5 to 7.5 years * GEO orbiting distance is greater than LEO orbiting distance, causing weaker signal than LEO signal strength * GEO is more economical because the costly launch of new LEO satellite every 5 years * Twice a year the sun crosses behind each GEO satellite as it is viewed from the ground station causing a temporary loss of signal due to the thermal noise from the sun with the satellite (5) * signals causes a temporary loss of signal
Comparing Low Earth Orbit (LEO) to Geo-synchronous Earth Orbit satellites (GEO) the differences are:

LEO, MEO and GEO orbits

4) What did the terrestrial mobile phone companies do to cope with their narrow service region?
The mobile cell companies seeing the “threat of substitution” by the satellite phone services, made a

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