Spacecraft cellular communication system

• US 5,974,315 A
• Filed: 10/31/1997
• Issued: 10/26/1999
• Est. Priority Date: 09/03/1997
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Hudson, Van Wakeman
• Primary Examiner(s): Bost, Dwayne D.
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US08/961,938
• Time in Patent Office: 725 Days
• Field of Search: 455/427, 455/430, 455/456, 455/445, 455/12.1, 455/13.1, 370/522, 370/316, 370/319, 370/321, 370/324, 370/347
• US Class Current: 455/427
• CPC Class Codes: H04B 7/18558 Arrangements for managing communications, i.e. for setting up, maintaining or releasing a call between stations

Abstract

A satellite (S/C) cellular commsystem includes user terminals (UT) for transmitting to, & receiving signals from the S/C, and includes gateways for transmitting to the S/C. The gateways receive and distribute signals from the S/C. Each gateway identifies itself to a UT by use of a location area identity signal, including codes representing (a) the gateway residence country, (b) the system with which the gateway is associated, and (c) the antenna beam on which service is provided. A network controller (NC 18) transmits location area identity codes, representing (a) the identity of the S/C communication system, (b) the satellite carrying the control signal, and (c) the particular antenna beam on which the control signal is transmitted. The UTs store the location area identity signals, and further include a comparator for comparing the identity signals received from the NCC with the stored identity signals. If they are the same, no update is required. If they are different, the UT requests access from the NCC. Upon receiving access, the UT transmits to a gateway the current location area identity, and also updates its own memory, so that at the next turn-on the UT is likely to find that the codes match, and no update is required.

Claims

1. A spacecraft cellular communication system, comprising;

a plurality of terrestrial user terminals for transmitting signals to said spacecraft, and for receiving signals from said spacecraft;

a plurality of terrestrial gateways, for receiving signals from land lines and transmitting said signals received from land lines over uplink frequency bands to said spacecraft, and for receiving signals over downlink frequency bands from said spacecraft, and for coupling to land lines at least some of said signals received from said spacecraft, each of said gateways including means for accepting communications from a user terminal over an identified communication channel;

a spacecraft including a transmitting/receiving arrangement, and an antenna arrangement coupled to said transmitting/receiving arrangement, which antenna arrangement generates a plurality of spot beams, each in a different direction, so that each beam overlies a different terrestrial footprint, for receiving a plurality of carriers at different frequencies lying within one of said uplink frequency bands, and for converting at least some of said plurality of carriers to a different frequency lying within a downlink frequency band, and for transmitting each of said downlink frequency bands on a particular one of said spot beams, whereby said spacecraft can communicate with gateways and user terminals by way of antenna beams associated with footprints within which said gateways and user terminals, respectively, lie;

at least some of said user terminals further including data storage means preloaded with said Country Code and Mobile Network Code of a Subscriber International Mobile Subscriber Identity, which identify the country of the subscriber'"'"'s network provider and the identity of said subscriber '"'"'s network provider, respectively, said user terminal further including a source of called party number, said called party number further including a Country Code and at least a National Destination Code, said user terminal further including transmitting/receiving means for transmitting to a network control means, by way of said spacecraft, when a particular called party is selected by means of said source of called party number, an access request including access cause information identifying (a) the cause as a normal call originating from the user terminal, and (b) said Country Code and, if appropriate, National Destination Code of the called party, said user terminal further including means for initiating a call to a gateway over a communication channel identified by said network control means;

said network control means being coupled to said spacecraft and to at least some of said gateways by way of said spacecraft, said network control means including a memory preloaded with information linking each combination of said Country Code and, if applicable, said National Destination Code, to a single gateway, said network control means further including gateway selection means, responsive to said cause being a normal call, for addressing said memory with information derived from said Country Code and said National Destination Code, for retrieving the identity of said single gateway linked to one of (a) said Country Code alone, and (b) the combination of said Country Code and said National Destination Code, and for selecting a communication channel for communication between said single gateway and said user terminal, said network control means further including means for transmitting to said single gateway and to said user terminal the identity of said communication channel, whereby said user terminal initiates communication with said single gateway over said selected communication channel.

2. A communication system according to claim 1, wherein:

said user terminal transmitting/receiving means includes means for transmitting to said network control means, by way of said spacecraft, when a particular called party is selected by means of said source of called party number, an access request including access cause information identifying (a) the cause as an local emergency call originating from the user terminal, and (b) said Country Code and, if appropriate, National Destination Code of the called party;

and said gateway selection means is further responsive to said local emergency call for addressing said memory with information derived from said Country Code and said National Destination Code, for retrieving the identity of said single gateway linked to one of (a) said Country Code alone, and (b) the combination of said Country Code and said National Destination Code, and for selecting a communication channel for communication between said single gateway and said user terminal, as in the case of a normal call.

5. A communication system according to claim 1, wherein:

said user terminal transmitting/receiving means includes means for transmitting to said network control means, by way of said spacecraft, when a particular called party is selected by means of said source of called party number, an access request including access cause information identifying (a) the cause as an local emergency call originating from the user terminal, and (b) said Country Code and, if appropriate, National Destination Code of the called party;

and said gateway selection means is further responsive to said local emergency call for addressing said memory with information derived from said Country Code and said National Destination Code, for retrieving the identity of said single gateway linked to one of (a) said Country Code alone, and (b) the combination of said Country Code and said National Destination Code, and for selecting a communication channel for communication between said single gateway and said user terminal, as in the case of a normal call.

3. A spacecraft cellular communication system, comprising;

a plurality of terrestrial user terminals for transmitting signals to said spacecraft, and for receiving signals from said spacecraft;

a plurality of terrestrial gateways, for receiving signals from land lines and transmitting said signals received from land lines over uplink frequency bands to said spacecraft, and for receiving signals over downlink frequency bands from said spacecraft, and for coupling to land lines at least some of said signals received from said spacecraft, each of said gateways including means for accepting communications from a user terminal over an identified communication channel;

a spacecraft including a transmitting/receiving arrangement, and an antenna arrangement coupled to said transmitting/receiving arrangement, which antenna arrangement generates a plurality of spot beams, each in a different direction, so that each beam overlies a different terrestrial footprint, for receiving a plurality of carriers at different frequencies lying within one of said uplink frequency bands, and for converting at least some of said plurality of carriers to a different frequency lying within a downlink frequency band, and for transmitting each of said downlink frequency bands on a particular one of said spot beams, whereby said spacecraft can communicate with gateways and user terminals by way of antenna beams associated with footprints within which said gateways and user terminals, respectively, lie;

at least some of said user terminals further including data storage means preloaded with said Country Code and Mobile Network Code of a Subscriber International Mobile Subscriber Identity, which identify the country of the subscriber'"'"'s network provider and the identity of said subscriber'"'"'s network provider, respectively, said user terminal further including a source of called party number, said called party number further including a Country Code and at least a National Destination Code, said user terminal further including transmitting/receiving means for transmitting to a network control means, by way of said spacecraft, when a particular called party is selected by means of said source of called party number, an access request including access cause information identifying (a) the cause as a normal call originating from the user terminal, and (b) said Country Code and, if appropriate, National Destination Code of the called party, said user terminal further including means for initiating a call to a gateway over a communication channel identified by said network control means;

said network control means being coupled to said spacecraft and to at least some of said gateways by way of said spacecraft, said network control means including a memory preloaded with information linking each combination of said Country Code and, if applicable, said National Destination Code, to a single gateway, said network control means further including gateway selection means, responsive to said cause being a normal call, for addressing said memory with information derived from said Country Code and said National Destination Code, for retrieving the identity of said single gateway linked to one of (a) said Country Code alone, and (b) the combination of said Country Code and said National Destination Code, and for selecting a communication channel for communication between said single gateway and said user terminal, said network control means further including means for transmitting to said single gateway and to said user terminal the identity of said communication channel, whereby said user terminal initiates communication with said single gateway over said selected communication channel.

4. A spacecraft cellular communication system, comprising;

a plurality of terrestrial user terminals for transmitting signals to said spacecraft, and for receiving signals from said spacecraft;

a plurality of terrestrial gateways, for receiving signals from land lines and transmitting said signals received from land lines over uplink frequency bands to said spacecraft, and for receiving signals over downlink frequency bands from said spacecraft, and for coupling to land lines at least some of said signals received from said spacecraft, each of said gateways including means for accepting communications from a user terminal over an identified communication channel;

a spacecraft including a transmitting/receiving arrangement, and an antenna arrangement coupled to said transmitting/receiving arrangement, which antenna arrangement generates a plurality of spot beams, each in a different direction, so that each beam overlies a different terrestrial footprint, for receiving a plurality of carriers at different frequencies lying within one of said uplink frequency bands, and for converting at least some of said plurality of carriers to a different frequency lying within a downlink frequency band, and for transmitting each of said downlink frequency bands on a particular one of said spot beams, whereby said spacecraft can communicate with gateways and user terminals by way of antenna beams associated with footprints within which said gateways and user terminals, respectively, lie;

at least some of said user terminals further including data storage means preloaded with said Country Code and Mobile Network Code of a Subscriber International Mobile Subscriber Identity, which identify the country of the subscriber'"'"'s network provider and the identity of said subscriber'"'"'s network provider, respectively, said user terminal further including a source of called party number, said called party number further including a Country Code and at least a National Destination Code, said user terminal further including transmitting/receiving means for transmitting to a network control means, by way of said spacecraft, when a particular called party is selected by means of said source of called party number, an access request including access cause information identifying (a) the cause as a normal call originating from the user terminal, and (b) said Country Code and, if appropriate, National Destination Code of the called party, said user terminal further including means for initiating a call to a gateway over a communication channel identified by said network control means;

said network control means being coupled to said spacecraft and to at least some of said gateways by way of said spacecraft, said network control means including a memory preloaded with information linking each combination of said Country Code and, if applicable, said National Destination Code, to a single gateway, said network control means further including gateway selection means, responsive to said cause being a normal call, for addressing said memory with information derived from said Country Code and said National Destination Code, for retrieving the identity of said single gateway linked to one of (a) said Country Code alone, and (b) the combination of said Country Code and said National Destination Code, and for selecting a communication channel for communication between said single gateway and said user terminal, said network control means further including means for transmitting to said single gateway and to said user terminal the identity of said communication channel, whereby said user terminal initiates communication with said single gateway over said selected communication channel.