Motorola Corporation

Craig Allen Long

William Robert Worger

Ernest Earl Woodward

Bradley Robert Schaefer

A method (,, FIG.,) controls CU (,, FIGS.,) hand-off in a non-geostationary orbit (NSGO) satellite system (,, FIG.,) without consuming large amounts of bandwidth or satellite processing power. Using method (,), a network control facility (NCF) (,, FIGS.,) divides the earth (,, FIG.,) into suitable regions,(FIG.,), or geographical areas of the earth sized so that all of the CUs (,, FIG.,) within a region (,) can be handed-off as a group rather than handling each station individually. When it is determined through the method (,) that it is time to hand-off communications in a particular region, all CUs within that region are directed to effectuate a hand-off at substantially the same time.

Method and apparatus for region based hand-offs in a satellite communication system

A communication system (,) has multiple satellites (,) communicating with ground stations (,) and with base stations (,). The satellites (,) are in non-geosynchronous orbit around the earth (,). A first ground station (,) transmits a data packet to a satellite (,). The data packet includes a sector number which represents an area on the earth (,) where the destination ground station (,) is located. The satellite (,) transmits the data packet to another satellite (,) if the satellite (,) is not serving an area identified by the sector number. This step is repeated until the data packet reaches a most likely satellite (,) that is most likely to be serving the area identified by the sector number. The most likely satellite (,) transmits the data packet to the destination ground station (,) if it is still serving the area identified by the sector number.

Method for sector-based routing

Equipment (10, 20) for facilitating point-to-point cryptographic data communication systems is disclosed. The seamless rekey cryptosystem permits changing of the crypto key (70, 80) with no down time. The cryptosystem will facilitate seamless key installation to eliminate data loss or reduce storage required while updating the crypto key. The seamless key will allow changing the key more often, which will also provide a more robust, secure cryptosystem.

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Mesa, AZ, United States of America

Craig Allen Long