Telecommunications – Carrier wave repeater or relay system – Portable or mobile repeater
Reexamination Certificate
1998-01-14
2001-02-06
Cumming, William (Department: 2749)
Telecommunications
Carrier wave repeater or relay system
Portable or mobile repeater
C455S427000
Reexamination Certificate
active
06185409
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a provisioning and management tool for managing a mobile satellite communication system, and more particularly, to a management tool for provisioning components in the satellite communication system including a mobile earth terminal satellite communication device. The mobile earth terminal provides voice, data, and facsimile transmission between mobile earth terminals and feederlink earth stations (FESs) that act as gateways to public networks or base stations associated with private networks.
BACKGROUND ART
Wireless technology is not new. The age of electronic communication began with the invention of a practical telegraph in 1844, over 150 years ago. It has been said that the telegraph was a major factor in the explosive development of the Western United States in the mid-1800's.
In 1983, the FCC issued licenses to provide mobile communications in a new frequency hand using a technique called cellular transmission which had been developed by both AT&T and Motorola. The proponents invested over $400 million in the new business before the FCC licensed cellular service. Many people thought that consumers needed mobile communications as much as they needed a second Jaguar automobile. Much to the surprise of everyone the growth rate was phenomenal. An enormous mass market developed for this service.
There are over 500 million users of wireline communications in the world today. By the early part of the next century, wireline will continue to grow, and wireless will be a major factor in telecommunications. According to the U.S. Commerce Department, there are at least 52 million cellular subscribers in the world (23 million in the U.S.). Within five years, experts estimate that there may be 150 million (50 million U.S.) and by 2005 we expect the worldwide total will be 260 million (65 million U.S.).
Cellular service is available in most urban regions, excluding, large, less developed areas. Service is not provided beyond the range of cells at which distances the signals are too weak. Cells typically do not exceed 10 miles in diameter, although super large cells have been created in the Caribbean. The new PCS service, which operates at much higher frequencies, requires even smaller cells, three times as many cells must be built as are required for cellular service. In regions where population density is low, the cost of building and operating transmission facilities may exceed the potential revenues. Wireless is sometimes blocked by terrain even in highly populated regions because the transmission signal arrives at low elevation angles.
Surveys show that customers currently are unhappy with unavailability and call blockage. Because of the low elevation angle transmission, service is sometimes interrupted during transmission or handover from cell to cell. During the peak busy hours, circuits are often blocked by other callers. Subscribers would like to enjoy wireless service all of the time, wherever they are.
Another major problem is that wireless transmission standards differ throughout the world. International travelers ar required to use different telephones when they travel to other regions. Even within the U.S. the new digital cellular service will be based on both time division multiple access (TDMA) and code division multiple access (CDMA) technology. Current plans suggest that digital cellular customers who roam up the East Coast will travel alternatively between systems that use different access methods.
Most of the world's telephone service is concentrated in the industrialized world. The 800 million people in industrialized countries have access to 400 million telephone lines, but 5 billion people in developing countries have access to only 200 million telephone lines. In Asia, more than 3 billion people have only 75 million telephone lines, and in Africa, with 500 million people, there is only one telephone per 1000 population.
The cost of closing the gap in developing countries has been estimated to be $3 trillion. Space based services are a faster and less costly solution. Large regions that are not served today could be economically served in the future with satellites. New systems hold the potential for extending service into regions that have been inaccessible or uneconomical to serve because of low population density or weak economic conditions.
Even in affluent, densely populated countries like Japan nd Germany, mountainous conditions prevent full coverage. Japanese cellular service operators expect that half of the land area will not be covered by terrestrial wireless. We are on the threshold of being able to provide universal, affordable wireless service throughout the world.
Wireless service is more expensive than wireline service, especially in urban regions. From a service provider perspective, the cost is higher because the call routing, call maintenance and billing is more complex. From a subscriber perspective, wireless telephone service adds great value. Wireless telephones allow mobile workers to talk while traveling. Mobile calls provide greater flexibility and permit communications in situations in which they were previously impossible.
Today, cellular systems offer service with a wide range of tariffs. typically, the systems charge a monthly service fee of about $30 plus an additional charge based on airtime. For local services, the airtime rates vary between $0.10 to $0.90 per minute, depending on the region of the country or the world. Often, service providers offer cellular telephones at a discount but require a one year service contract, payment for the telephone equipment being embedded within the service price structure.
Currently, satellite service is available worldwide as an alternative to cellular service, but the terminal cost and service rates are very high. Inmarsat signatories offer service for airtime rates ranging from $5 to $15 per minute. “Portable” terminals that cost at least $15,000 and have a mass of 10 kilograms (22 pounds) can be lugged on trips. Terrestrial cellular has 1000 times more customers at service rates which are a factor of ten lower than present space based systems. The prices are very elastic.
Manufacturers of handsets and satellite systems recognized that cellular type communications from space could be much less expensive in the future than it is today. Several companies have determined that space based wireless service can be provided at service rates which are affordable by a mass market.
The primary consideration for business success is having a cost effective product which customers desire. This means balancing the service charges to own a personal telephone as well as the air time rates with the needs of the subscriber. Cost must also be kept affordable and economical compared to alternatives. However, each system must strike a balance between low cost and high quality. As a business, the service and distribution functions must provide an outlet to the ultimate customer, the consumer.
In the mid 1960's we had correctly determined that the best orbit for fixed satellite service was a geostationary orbit. This choice was logical because a stationary orbit permitted satellites to appear fixed in the sky. Large, high gain ground terminals could be positioned to ensure that the transmission path always would be clear. Although large, the antennas had no need to track, since the satellites appeared motionless to it. Only three or four satellites were needed to view most of the globe (excepting the polar regions). Unfortunately, the distance to Geostationary Earth Orbit (GEO) is great (about 23,000 miles) and the propagation time delay produces overtalking and confusion.
During the 1980's, conditions developed for a major change in the satellite communications paradigm: Orbiting satellites closer to the Earth would permit more powerful transmission with reasonable sized satellites and antennas. In addition, inclined orbits could ensure high elevation angles to minimize blockage by buildings, and other obstacles. The microelectronics for
Lin Shih-Chao
Threadgill Michael E.
AMSC Subsidiary Corporation
Cumming William
Donner Irah H.
Hale and Dorr LLP
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