Satellite communications system having distributed user assignment and resource assignment with terrestrial gateways

• US 6,067,442 A
• Filed: 03/18/1997
• Issued: 05/23/2000
• Est. Priority Date: 10/10/1991
• Status: Expired due to Term

• Current Assignee: Globalstar Incorporated
• Original Assignee: Globalstar Incorporated
• Inventors: Wiedeman, Robert A., Monte, Paul A
• Primary Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US08/819,309
• Time in Patent Office: 1,162 Days
• Field of Search: 370/397, 370/486, 370/320, 455/3.1, 455/46.5, 455/438, 455/400, 455/13.1, 455/405, 348/7, 379/40, 379/39
• US Class Current: 455/13.1
• CPC Class Codes: H04B 7/18545 Arrangements for managing station mobility, i.e. for station registration or localisation
• CPC Class Codes: H04W 48/17 Selecting a data network PoA [Point of Attachment]
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

A satellite communications system (10) includes at least one satellite (12); a system controller (38); a plurality of gateways (18); and at least one user terminal (13) operable for bidirectionally communicating with at least one of the gateways through the at least one satellite. Individual ones of the plurality of gateways are bidirectionally coupled to at least one terrestrial communications system (4) and act to couple the user terminal to the terrestrial communication system through at least one satellite. In accordance with an aspect of this invention, individual ones of the plurality of gateways are operable for receiving an access request from the user terminal, through at least one satellite, and are further operable for notifying the requesting user terminal, through at least one satellite, that the user terminal is one of accepted by the gateway for establishing a communication link and not accepted by the gateway for establishing the communication link. A gateway that does not accept a user terminal can indicate to the user terminal, based at least in part on a determined location of the user terminal, an identification of a gateway to which the user terminal should apply for access or log-in purposes. The system further includes a data network (39) that interconnects the system controller and the plurality of gateways. The data network may be conveyed by and embodied in one of a wired network, a wireless network, and a combination of a wired network and a wireless network.

Claims

1. A satellite communications system, comprising:

at least one satellite;

a plurality of gateways; and

at least one user terminal comprising means for bidirectionally communicating with at least one of said gateways through said at least one satellite;

wherein individual ones of said plurality of gateways comprise means for receiving an access request from said at least one user terminal through said at least one satellite, and further comprise means for notifying said requesting user terminal through said at least one satellite that the user terminal is one of accepted by the gateway for establishing a communication link or not accepted by the gateway for establishing the communication link, wherein said notifying means of each of said plurality of gateways makes a decision as to whether to accept a requesting user terminal or to not accept a requesting user terminal based on at least one criterion being satisfied and without requiring decision making assistance from said at least one satellite.

2. A satellite communications system as set forth in claim 1, wherein said plurality of gateways are bidirectionally coupled to a data network, and wherein said data network is comprised of at least one of a terrestrial segment and a space segment.

3. A satellite communications system as set forth in claim 1, wherein individual ones of said gateways further comprise means for determining a location of a user terminal, and wherein said notifying means is responsive at least in part to said determined location for determining whether to accept the user terminal.

4. A satellite communications system as set forth in claim 1, wherein said at least one user terminal is comprised of means for storing a list identifying individual ones of said plurality of gateways, and wherein said user terminal further comprises means for selecting a gateway from the list to which to send an access request.

5. A satellite communications system as set forth in claim 4, wherein said list is received by said user terminal, through said at least one satellite, from one of said plurality of gateways.

6. A satellite communications system as set forth in claim 1, wherein said at least one user terminal is comprised of means for initially tuning to a frequency channel that was last used by the user terminal and, if the last used frequency channel is not available, for tuning to one or more predetermined channels.

7. A satellite communications system, comprising:

at least one user terminal comprising a first transceiver for transmitting signals, including a request for service signal, to a first RF link and for receiving signals from said first RF link;

at least one satellite comprising means for receiving signals from and for transmitting signals to said first Rf link and for transmitting signals to and receiving signals from a second RF link; and

at least one gateway, said at least one gateway having at least one service area associated therewith and comprising a second transceiver for transmitting signals to and for receiving signals from said second RF link, said second transceiver being bidirectionally coupled to at least one terrestrial communication network for forwarding a communication signal for said at least one user terminal from said at least one communication network to said second RF link and for forwarding a communication signal from said at least one user terminal from said second RF link to said at least one communication network, said at least one gateway further comprising decision means having an input for receiving, from said second RF link, a request for service signal from said at least one user terminal, said decision means operating to determine whether to accept or not accept the request for service from a requesting user terminal in accordance with at least one criterion, wherein said decision means of said at least one gateway makes a decision as to whether to accept a requesting user terminal or to not accept a requesting user terminal based on said least one criterion being fulfilled and without requiring decision making assistance from said at least one satellite.

8. A system as set forth in claim 7, wherein said at least one gateway is further comprised of means for determining a location of said at least one user terminal, and wherein said decision means is responsive to said location determining means for determining whether said at least one criterion is fulfilled.

9. A system as set forth in claim 7, wherein said user terminal includes means for receiving, from said first RF link, at least one reference signal that is transmitted by said at least one gateway, and wherein said user terminal directs said request for service to a selected gateway based at least in part on at least one received reference signal.

10. A system as set forth in claim 9, wherein said at least one user terminal directs a request for service to a gateway selected in accordance with a received reference signal that has a greatest received signal strength.

11. A system as set forth in claim 7, wherein there are a plurality of gateways each of which has a gateway identifier, each of said plurality of gateways further comprising means for transmitting a list comprised of at least one other gateway identifier to said second RF link, and wherein said at least one user terminal is further comprised of means for storing said list that is received from said first RF link.

12. A system as set forth in claim 11, wherein said at least one user terminal directs a request for service to a gateway having a gateway identifier in said stored list.

13. A system as set forth in claim 8, wherein there are a plurality of gateways each of which has a gateway identifier, each of said plurality of gateways further comprising means for transmitting at least one gateway identifier to said second RF link for reception by said at least one user terminal when not accepting a request for service from said at least one user terminal, said at least one transmitted gateway identifier being selected at least in part in accordance with said determined location so as to indicate, to said user terminal, a gateway having a service area within which the user terminal is determined to be located.

14. A method for operating a telecommunications system having at least one earth orbiting satellite for conveying signals between a user terminal and one of a plurality of gateways, at least one of the gateways being coupled to a terrestrial telecommunications system, comprising the steps of:

in the user terminal, attempting to receive a signal from a last-used gateway;

if successful, transmitting an access request to the last-used gateway;

if unsuccessful, attempting to receive a predetermined communications channel;

if successful, obtaining a list of gateways from a gateway transmitting the predetermined communications channel and storing the list of gateways within the user terminal;

determining if a predetermined gateway is included within the list of gateways and, if yes, transmitting an access request from the user terminal to the predetermined gateway;

if the predetermined gateway is determined to not be included within the list, selecting one of the gateways from the list and transmitting the access request to the selected gateway; and

in a gateway receiving the transmitted access request through said at least one satellite, making a decision as to whether to accept the user terminal that transmitted the access request or to not accept the user terminal based on at least one criterion being fulfilled and without requiring decision making assistance from the at least one satellite.

15. A method as set forth in claim 14, wherein the step of making a decision comprises the steps of:

at the gateway receiving the access request, determining a location of the user terminal;

determining, based at least in part on the determined location, whether to accept the user terminal for establishing a communication with one of terminal coupled to a terrestrial telecommunications system or with another user terminal; and

if the user terminal is accepted, authenticating the user terminal and assigning at least one satellite traffic channel to the authenticated user terminal.

16. A method as set forth in claim 15, and further comprising the steps of:

if the gateway determines not to accept the user terminal, notifying the user terminal of non-acceptance;

in the user terminal, removing the gateway from the gateway list and selecting another gateway from the list for making a next access request.

17. A method as set forth in claim 14, wherein the step of selecting a gateway includes an initial step of acquiring a reference signal from at least some gateways in the list and selecting one of the gateways in accordance with at least one characteristic of the acquired reference signals.

18. A method as set forth in claim 14, wherein the step of making a decision comprises the steps of:

at the gateway receiving the access request, performing an authentication of the requesting user terminal;

if the user terminal is not authenticated, rejecting the access request;

if the user terminal is authenticated, determining a location of the user terminal;

determining, based at least in part on the determined location, whether to accept the user terminal for establishing a communication with one of a terrestrial telecommunications system or another user terminal; and

if the user terminal is accepted, assigning at least one satellite traffic channel to the authenticated user terminal.

19. A method as set forth in claim 18, and further comprising the steps of:

if the gateway determines not to accept the user terminal, notifying the user terminal of non-acceptance;

in the user terminal, removing the gateway from the gateway list; and

selecting another gateway from the list for making a next access request.

20. A method for operating a telecommunications system having at least one earth orbiting satellite for conveying signals between a user terminal and one of a plurality of gateways, at least one of the gateways being coupled to at least one terrestrial telecommunications system, comprising the steps of:

receiving, at a gateway, a service request from the user terminal, the service request passing through the at least one satellite; and

based on at least one criterion, notifying the requesting user terminal that the user terminal is one of accepted by the gateway for establishing a communication link or not accepted by the gateway for establishing the communication link, the step of notifying comprising a step, executed in a gateway that receives the service request through the at least one satellite, of making a decision as to whether to accept the user terminal that transmitted the service request or to not accept the user terminal based on the at least one criterion being fulfilled and without requiring decision making assistance from the at least one satellite.

21. A method as set forth in claim 20, wherein the step of notifying includes a step of assigning at least one satellite traffic channel to an accepted user terminal.

22. A method as set forth in claim 20, wherein the step of notifying includes a step of transmitting an identification of at least one other gateway to a non-accepted user terminal, and further comprising the step of making a next service request to the identified gateway.

23. A method as set forth in claim 20, and comprising the initial steps of:

in the user terminal, acquiring a reference signal from a first gateway;

receiving a list identifying at least one other gateway from the first gateway;

receiving a reference signal from the at least one other gateway in the list; and

selecting a gateway having a reference signal with a greatest received signal strength.

24. A method as set forth in claim 20, wherein the at least one criterion includes at least one of a location of the user terminal, a current communications traffic loading of the gateway, a predicted communications traffic loading of the gateway, the presence or absence of any RF impairments, a type of user terminal, a lowest cost routing for a call, a destination for a call, and a presence or absence of a roaming agreement with the requesting user terminal'"'"'s service provider.

25. A method as set forth in claim 20, and comprising the initial steps of:

in the user terminal, acquiring a reference signal from a gateway; and

in accordance with information obtained from the reference signal, transmitting a service request to the gateway.

26. A method as set forth in claim 20, wherein the step of notifying includes a step of not responding to the service request from a non-accepted user terminal, and further comprising the steps of:

in the user terminal, waiting for a predetermined period of time to receive a response from the gateway; and

at the expiration of the predetermined period of time, making a next service request to another gateway.

27. A method for operating a telecommunications system having at least one earth orbiting satellite for conveying signals between a user terminal and one of a plurality of gateways, at least one of the gateways being coupled to at least one terrestrial telecommunications system, comprising the steps of:

receiving a service request that is transmitted from the user terminal; and

based on at least one criterion, determining if the requesting user terminal is accepted for service and notifying the requesting user terminal that the user terminal is one of accepted for service or not accepted for service, wherein the at least one criterion includes at least one of a location of the user terminal, a current communications traffic loading of the system, a predicted communications traffic loading of the system, the presence or absence of any system impairments, a type of user terminal, and the presence or absence of a roaming agreement with the requesting user terminal'"'"'s service provider, and wherein the steps of deciding and notifying are executed in a gateway that receives the service request through the at least one satellite, wherein the decision as to whether to accept the user terminal that transmitted the service request or to not accept the user terminal is based on the at least one criterion and without requiring decision making assistance from the at least one satellite.

28. A method for operating a telecommunications system having at least one earth orbiting satellite for conveying signals between a user terminal and one of a plurality of gateways, comprising the steps of:

receiving a service request that is transmitted from the user terminal, the service request being received at a first gateway and indicating a destination telephone number to which a call is to be placed;

determining in the first gateway if the first gateway is capable of serving the destination telephone number; and

, if not,

transmitting a message to the user terminal, the message rejecting the service request and including an indication of another gateway that is capable of serving the destination telephone number.

29. A method as in claim 28, wherein the destination telephone number corresponds to a telephone number of a non-public network.

30. A method as in claim 28, wherein the destination telephone number corresponds to a telephone number of a another user terminal.

31. A method for operating a telecommunications system having at least one earth orbiting satellite for conveying signals between a user terminal and one of a plurality of gateways, comprising the steps of:

receiving a service request that is transmitted from the user terminal, the service request being received at a first gateway and indicating a destination telephone number to which a call is to be placed;

determining in the first gateway if the first gateway can connect the call to the destination telephone number at less expense than another gateway can connect the call to the destination telephone number; and

, if not,

transmitting a message to the user terminal from the first gateway, the message rejecting the service request and including an indication of at least one other gateway that is determined to be capable of connecting the call with less expense than the first gateway.