System and method for mobile communications in coexistence with established communications systems

• US 5,511,233 A
• Filed: 04/05/1994
• Issued: 04/23/1996
• Est. Priority Date: 04/05/1994
• Status: Expired due to Term

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: Celsat America, Inc.
• Inventors: Otten, David D.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): BANKS HAROLD, MARSHA DENISE
• Application Number:
  US08/223,437
• Time in Patent Office: 749 Days
• Field of Search: 455/12.1, 455/33.1, 455/33.2, 455/33.4, 455/54.1, 455/56.1, 455/63, 455/68, 455/34.1, 455/34.2, 455/62, 455/67.3, 455/67.5, 370/18, 375/1, 379/59, 379/63
• US Class Current: 455/524
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message
• CPC Class Codes: H04B 7/18563 Arrangements for interconnecting multiple systems data switching networks H04L12/00
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A mobile communications system provides communications with mobile users in the interference zones of communications services having priority of use of the frequency band in which the mobile user operates. The frequency band has been previously allocated for use by the other services, such as fixed microwave service (FMS); however, by means of the invention, the mobile user is able to conduct communications operations on a subband or subbands in that frequency band. A position locating system determines the position of the mobile user and if the user is within an interference zone, the mobile user is assigned subbands for operation in the previously allocated frequency band that are outside the subbands of operation of the FMS. A memory accessible by the processor selecting the frequency band of operation of the mobile user includes descriptions of the transmit and receive interference zones of each FMS. The processor selects the frequency subband of operation of the mobile user based on its position relative to the interference zone or zones. The system may have surface and/or space nodes and a network controller that monitors the mobile user'"'"'s position and controls the nodes and user to subbands. Mobile users are isolated from the fixed microwave sites either by continuous management of their frequency assignments by calculations and commands sent from the network controller to the mobile user or by computations by the mobile user'"'"'s unit. The mobile system is frequency agile by operating in dynamically selectable frequency subbands.

Claims

1. A communications system for providing communications with a mobile user in a frequency band and in the geographic vicinity of a different communications service that operates in at least one sub-band that uses some but not all of the frequency band, while avoiding mutual interference between the mobile user and the different communications service, the communications system comprising:

a mobile communication device used by the mobile user, the communication device being responsive to a frequency control signal to select the frequency sub-band in which it operates; and

a control center for communicating the frequency control signal to the mobile communication device, the control center comprising;

a memory in which is stored a geographic and frequency description of the different communications service thereby defining an interference zone for the different communications service;

a position locating system adapted to determine the position of the mobile user and provide a position signal; and

a processor adapted to receive the position signal and access the memory to retrieve the description of the interference zone of the different communications service, the processor further operative to compare the position of the mobile user to the interference zone and if the user is determined to be within the interference zone, provide a frequency control signal to the mobile communication device to select a frequency sub-band in the frequency band other than the frequency sub-band or sub-bands used by the different communications service.

2. The communications system of claim 1 wherein the mobile communication device comprises the position locating system.

3. The communications system of claim 1 wherein the mobile communication device comprises the memory and the processor.

4. The communications system of claim 3 wherein the mobile communication device further comprises the position locating system.

5. The communications system of claim 1 wherein the mobile communication device is adapted to delay transmission by the mobile communication device until the processor has determined the position of the user and if the user'"'"'s position is determined to be within the interference zone, to delay transmission until the processor has provided the frequency control signal to select a frequency sub-band other than the frequency sub-band or sub-bands used by the different communications service.

6. The communications system of claim 1 further comprising a first communication node adapted to provide communication with the mobile communication device, the node providing the frequency control signal from the processor to the communication device of the mobile user.

7. The communications system of claim 6 wherein the first communication node comprises a surface node and the communications system comprising at least one additional surface node, each of which is adapted to communicate with the mobile communication device and a surface node control center, wherein the surface node control center comprises the position locating system, the processor, and the memory, the surface node control center communicating the frequency control signal from the processor to the mobile communication device through a surface node.

8. The communications system of claim 6 wherein the first communication node comprises a space node and the communications system comprising at least one additional space node, each of which is adapted to communicate with the mobile communication device, and a space node control center, wherein the space node control center comprises the position locating system, the processor, and the memory, the space node control center communicating the frequency control signal from the processor to the mobile communication device through a space node.

9. The communications system of claim 6 further comprising a plurality of surface nodes and space nodes, each node adapted to communicate with the mobile communication device, and a control center, wherein the control center comprises the position locating system, the processor, and the memory, the control center communicating the frequency control signal from the processor to the mobile communication device through a node.

10. The communications system of claim 9 further comprising a surface node control center in communication with each of the surface nodes, a space node control center in communication with each of the space nodes and wherein the surface node control center and space node control center are connected to a network control center that comprises the position locating system, the processor, and the memory, the network control center communicating the frequency control signal from the processor to the mobile communication device through a node control center and a node.

11. The communications system of claim 10 wherein the position locating system determines the geographic location of the mobile user through multilateration with a plurality of nodes.

12. The communications system of claim 1 further comprising:

at least one space node having a multiple beam antenna positioned so to establish a first set of cells, each space node being capable of transmitting and receiving different predetermined sets of code division multiple access coded, spread spectrum waveforms;

at least one surface node positioned so to establish a second set of cells, each surface node being capable of transmitting and receiving the predetermined sets of code division multiple access coded, spread spectrum waveforms; and

a network controller operationally connected with each space node and with each surface node to selectively allocate communications with the mobile user among the surface and space nodes and select the subband of operation of the mobile user based on the frequency control signal.

13. The communications system of claim 1 wherein:

the memory stores geographic and frequency descriptions of a plurality of different communications services thereby defining an interference zone for each of the different communications services;

the processor is also adapted to access the memory to retrieve the descriptions of the interference zones of the different communications services, compare the position of the mobile user to the interference zones and if the user is determined to be within an interference zone, provide a frequency control signal to the mobile communication device to select a frequency sub-band in the frequency band other than the frequency sub-band or sub-bands used by the communications service of the interference zone in which the mobile user is located.

14. A communications system for providing communications with a mobile user in the frequency bands and in the geographic vicinities of different communications services having fixed positions and that operate in sub-bands that use some but not all of the frequency band as the mobile user, while avoiding mutual interference between the mobile user and the different communications services, the communications system comprising:

a mobile communication device used by the mobile user, the communication device being responsive to a frequency control signal to select the frequency sub-band in which it operates;

a plurality of surface nodes adapted to communicate with the mobile communication device;

a memory in which is stored geographic and frequency descriptions of the different communications services thereby defining an interference zone for each of the different communications services;

a position locating system adapted to determine the position of the mobile user and provide a position signal;

a processor adapted to receive the position signal, access the memory to retrieve the descriptions of the interference zones of the communications services, compare the position of the mobile user to the interference zone descriptions and if the user is determined to be within an interference zone, provide a frequency control signal to the mobile communication device to select a frequency sub-band in the frequency band other than the frequency sub-band or sub-bands of the communications service of the interference zone in which the mobile user is located; and

a surface node control center, wherein the surface node control center comprises the position locating system, the processor, and the memory, the surface node control center communicating the frequency control signal from the processor to the mobile communication device through a surface node.

15. A communications system for providing communications with a mobile user in the frequency bands and in the geographic vicinities of different communications services having fixed positions and that operate in sub-bands that use some but not all of the frequency band as the mobile user, while avoiding mutual interference between the mobile user and the different communications services, the communications system comprising:

a mobile communication device used by the mobile user, the communication device being responsive to a frequency control signal to select the frequency sub-band in which it operates;

a plurality of space nodes adapted to communicate with the mobile communication device;

a memory in which is stored geographic and frequency descriptions of the different communications services thereby defining an interference zone for each of the different communications services;

a position locating system adapted to determine the position of the mobile user and provide a position signal;

a processor adapted to receive the position signal, access the memory to retrieve the descriptions of the interference zones of the communications services, compare the position of the mobile user to the interference zone descriptions and if the user is determined to be within an interference zone, provide a frequency control signal to the mobile communication device to select a frequency sub-band in the frequency band other than the frequency sub-band or sub-bands of the communications service of the interference zone in which the mobile user is located; and

a space node control center, wherein the space node control center comprises the position locating system, the processor, and the memory, the space node control center communicating the frequency control signal from the processor to the mobile communication device through a space node.

16. A method for communicating with a mobile user having a communications device in a frequency band and in the geographic vicinity of a different communications service that operates in at least one sub-band that uses some but not all of the frequency band, while avoiding mutual interference between the mobile user and the different communications service, the method comprising the steps of:

storing in a memory a geographic and frequency description of the different communications service thereby defining an interference zone for the different communications service;

determining the position of the mobile user;

accessing the memory to retrieve the description of the different communications service; and

comparing the position of the mobile user to the interference zone of the different communications service and if the user is determined to be within the interference zone, providing a frequency control signal to the mobile communication device to select a sub-band in the frequency band other than the frequency sub-band or sub-bands of the communications service.

17. The method of claim 16 wherein the step of determining the position of the mobile user comprises the step of determining the mobile user'"'"'s position by a position location device located at the mobile communications device.

18. The method of claim 16 wherein the steps of storing a description of the interference zone, accessing the memory to retrieve the description of the interference zone of the communications service, and comparing the position of the mobile user to the interference zone are performed at the mobile communications device.

19. The method of claim 18 wherein the step of determining the position of the mobile user comprises the step of determining the mobile user'"'"'s position by a position location device located at the mobile communications device, the position location device being coupled to the mobile communication device.

20. The method of claim 16 further comprising the step of:

delaying transmissions of the mobile communication device until after determining the position of the user and if the user'"'"'s position is determined to be within the interference zone, delaying the user'"'"'s transmission until the frequency control signal has been provided to select a sub-band other than the sub-band or sub-bands of the different communications service.

21. The method of claim 16 further comprising the step of:

configuring a first communication node to perform the step of communicating with the mobile communication device; and

providing the frequency control signal to the communication device of the mobile user from the first communication node.

22. The method of claim 21 further comprising the steps of:

configuring a plurality of geographically separated surface nodes to communicate with the mobile communication device;

configuring a surface node control center for performing the steps of;

coordinating communications with the mobile user through the surface nodes;

determining the position of the mobile user;

storing a description of the interference zone;

accessing the memory to retrieve the description of the interference zone of the different communications service; and

comparing the position of the mobile user to the interference zone and providing the frequency control signal through a node.

23. The method of claim 21 further comprising the steps of:

configuring a plurality of geographically separated space nodes to communicate with the mobile communication device;

configuring a space node control center for performing the steps of;

coordinating communications with the mobile user through the space nodes;

determining the position of the mobile user;

storing a description of the interference zone;

accessing the memory to retrieve the description of the interference zone of the communications service; and

comparing the position of the mobile user to the interference zone and providing the frequency control signal through a node.

24. The method of claim 21 further comprising the steps of:

configuring a plurality of geographically separated surface nodes and space nodes to communicate with the mobile communication device;

configuring a control center for performing the steps of;

coordinating communications with the mobile user through the nodes;

determining the position of the mobile user;

storing a description of the interference zone of the different communications service;

accessing the memory to retrieve the description of the interference zone of the different communications service; and

comparing the position of the mobile user to the interference zone and providing the frequency control signal through a node.

25. The method of claim 24 further comprising the steps of:

coupling each of the surface nodes to a surface node control center;

coupling each of the space nodes to a space node control center;

wherein the step of configuring a control center comprises the step of configuring the control center as a network control center to perform the steps of;

coordinating communications with the mobile user through the nodes;

determining the position of the mobile user;

storing a description of the interference zone;

accessing the memory to retrieve the description of the interference zone of the different communications service; and

comparing the position of the mobile user to the interference zone and providing the frequency control signal through a node.

26. The method of claim 25 wherein the step of determining the user'"'"'s position comprises the step of determining the geographic location of the mobile user through multilateration using a plurality of nodes.