Trw Limited

Michael Horstein

Peter H Cress

Roger J Rusch

Hau H Ho

A method of controlling communication satellite system capacity in a satellite-based cellular telecommunication system where two or more communication satellites provide coverage of a service region. Communication satellites are assigned to mobile cellular stations in a manner designed to minimize the maximum single-satellite power that is required for the communication satellites collectively to supply a specified number of transmissions to the service region. The service region may be divided into grids, where each grid is characterized by a number which is proportional to the average number of active mobile cellular stations. This information, in conjunction with a power utilization factor associated with each satellite/grid pair, is used to determine the assignments of the communication satellites to the mobile cellular stations.

Communication satellite load balancing system and method

A satellite-based cellular telecommunications system employing a constellation of telecommunications satellites in medium earth orbit to provide multibeam radio frequency (rf) communications links for worldwide cellular telephone service with a minimum number of satellites. The telecommunications satellites are placed in a plurality of inclined orbits about the earth at an altitude of between approximately 5600 and 10,000 nautical miles. The characteristics of the orbits, such as the number of orbits, the inclination of each orbit, the number of satellites in each orbit and the altitude of the satellites, are tailored to maximize the coverage area of the satellites and their related line-of-sight elevation angles, while minimizing propagation time delays, the number of beam-to-beam and satellite-to-satellites handovers, and the total number of satellites. The present invention also includes several additional features which essentially eliminate beam-to-beam and satellite-to-satellite handovers, thus dramatically reducing the likelihood of dropouts.

Medium-earth-altitute satellite-based cellular telecommunications

A method of initiating communication between a ground station and a mobile handset through a satellite beam includes the steps of transmitting a forward signal indicative of a fixed geographic area covered by each of a plurality of satellites on at least a periodic basis. The location of said mobile handset is registered by storing at least one variable geographic value associated with said forward control signal at said mobile handset. A reverse signal is transmitted from said mobile handset to said ground station which is indicative of a geographic area where said mobile handset was located during registration. At least one variable geographic value associated with said reverse signal is stored in a database accessible to said ground station. The mobile handset determines whether a currently transmitted forward signal matches said variable geographic value stored. If a match is not found, the current location of said mobile handset is re-registered. The ground station determines which of said satellite beams should initiate a call signal to said mobile handset based upon said variable geographic value stored in said database for said mobile handset.

User paging for mobile satellite communications

Medium-earth-altitude satellite-based cellular telecommunications

A satellite-based cellular telecommunications system employing a constellation of telecommunications satellites in medium earth orbit to provide multibeam radio frequency (rf) communications links for worldwide cellular telephone service with a minimum number of satellites. The telecommunications satellites are placed in a plurality of inclined orbits about the earth at an altitude of between approximately 5600 and 10,000 nautical miles. The characteristics of the orbits, such as the number of orbits, the inclination of each orbit, the number of satellites in each orbit and the altitude of the satellites, are tailored to maximize the coverage area of the satellites and their related line-of-sight elevation angles, while minimizing propagation time delays, the number of beam-to-beam and satellite-to-satellite handovers, and the total number of satellites. The present invention also includes several additional features which essentially eliminate beam-to-beam and satellite-to-satellite handovers, thus dramatically reducing the likelihood of dropouts. between the plug and the anchor to prevent the plug from entering the opening in the vessel.

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Los Angeles, CA, United States of America

Michael Horstein