Non-geostationary satellite mobile communication system integration with network principles for terrestrial cellular

• US 5,867,765 A
• Filed: 03/31/1995
• Issued: 02/02/1999
• Est. Priority Date: 03/31/1995
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Nilsson, Mats
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): BANKS HAROLD, MARSHA DENISE
• Application Number:
  US08/414,099
• Time in Patent Office: 1,404 Days
• Field of Search: 455/12.1, 455/13.1, 455/13.2, 455/33.1, 455/33.2, 455/34.1, 455/54.1, 455/53.1, 455/56.1, 455/62, 455/63, 455/422, 455/427, 455/428, 455/436, 455/524, 379/60
• US Class Current: 455/13.1
• CPC Class Codes: H04B 7/18541 for handover of resources
• CPC Class Codes: H04B 7/1855 using a telephonic control signal, e.g. propagation delay variation, Doppler frequency variation, power variation, beam identification

Abstract

A non-geostationary satellite communication system comprises a cellular system controller, a satellite system controller, and a management controller. The cellular system controller assigns each mobile station in the cellular system to a specific region and creates a record of such assignment, wherein each mobile station periodically updates its location within the system. The satellite system controller tracks the position and motion of the satellite and assigns and records the assignment of terrestrial regions, i.e., radio resources, to each satellite, and periodically hands off coverage of one region from one satellite to another. The management controller maps the region assignment records of the mobile stations with the satellite assignment records of the regions so as to perform mobility functions, handover, and location management due to the motion of the satellites and the mobile stations.

Claims

1. A communication system that provides communication coverage for moving mobile stations within a communication site that is divided into regions, each having a radio resource assigned thereto, comprising:

a land-based cellular communication system that assigns the mobile stations to a specific region as the mobile stations move within the communication site, said land-based cellular communication system including a cellular system controller that creates an up-datable mobile station assignment record according to the location of the mobile station within the communication site;

a non-geostationary satellite communication system that tracks the position of a plurality of satellites that cover the communication site and assigns at least one of the specific regions to at least one of the plurality of satellites;

wherein the non-geostationary satellite communication system includes a satellite system controller that creates a satellite assignment record according to the assignment of the at least one satellite; and

a communication management controller that accesses the mobile station assignment record and the satellite assignment record for assigning the mobile stations to one of the plurality satellites in accordance with the position of the plurality of satellites and the location of the mobile stations.

2. A communication system according to claim 1, wherein said regions are assigned specific frequencies using a frequency reuse pattern.

3. A communication system according to claim 1, wherein each region is assigned a specific set of timeslots.

4. A communication system according to claim 1, wherein each region is assigned a specific set of spread spectrum codes.

5. A conununication system according to claim 1, wherein said non-geostationary satellite communication system updates said up-datable mobile station assignment record according to the location of mobile stations within the communication site.

6. A communication system according to claim 5, wherein said non-geostationary satellite communication system updates said up-datable mobile station assignment record only for mobile stations that are outside of a specific region for which communication coverage is provided by the land-based cellular communication system.

7. A satellite cellular commnunications system, comprising:

a satellite communications system comprising a plurality of satellites for transmitting and receiving a plurality of signals, wherein each satellite is assigned a certain coverage area for a predetermined period of time, and a plurality of land earth stations for communicating with said satellites over feederlinks;

a land based cellular communications system;

a plurality of mobile stations which can communicate with each other and other communication stations using the satellite system through the cellular system;

control means for handing off coverage areas from one satellite to another based on said assignment of coverage areas due to the motion of the satellites, wherein the decision to handoff is made based on information recieved from protocols used by said land-based cellular communication system, wherein said satellite system uses regionally oriented frequency assignment.

8. A satellite cellular communications system according to claim 7, wherein said coverage areas are assigned specific frequencies using a frequency reuse pattern.

9. A satellite/cellular communications system according to claim 7, wherein each of said coverage areas is assigned a specific set of timeslots.

10. A satellite/cellular communications system according to claim 7, wherein each of said coverage area is assigned a specific set of spread spectrum codes.

11. The satellite cellular communications system of claim 7, wherein a mobile station updates its location at a call setup, based on information recorded in the land based cellular communications system.

12. The satellite/cellular communications system of claim 7, wherein a mobile station periodically updates its location, based on information recorded in the land-based cellular communications system.

13. A communication system hat provides communication coverage within a communication site that is divided into terrestrial coverage and satelite coverage regions, comprising:

a plurality of mobile stations moving within the terrestrial coverage and satellite coverage regions;

a land-based cellular communications system for providing communication coverage within the terrestrial coverage regions including a cellular controller that assigns terrestrial coverage regions to the mobile station as the mobile station moves within the communication site, wherein the cellular system controller creates a region assignment record according the assignment of the mobile stations to the terrestrial coverage and satellite coverage regions,

a non-geostationary satellite communication system including;

a plurality of orbiting satellites, each satellite providing communication coverage within an assigned satellite coverage region; and

a satellite system controller that tracks the plurality of orbiting satellites and based on their positions, assigns a corresponding satellite overage region to each satellite, wherein the satellite system controller creates a satellite coverage assignment record according to the assignment of the satellite coverage regions to the satellites; and

a communication management controller that accesses the terrestrial assignment record and the satellite assignment record for assigning the mobile station to a satellite coverage region or a terrestrial coverage region in accordance with the location of the mobile station.

14. A communication system according to claim 13, wherein said non-geostationary satellite communication system updates the region assignment record, based on the location of the mobile stations.

15. A communication system according to claim 13, wherein said non-geostationary satellite communication system updates the region assignment record only for those mobile stations that are outside of the terrestrial coverage region.

16. A method of communicating with a communication unit, comprising the steps of:

dividing a communication site into terrestrial coverage regions and satellite coverage regions;

providing communication coverage within the terrestrial coverage regions through a land-based cellular communication system;

providing communication coverage within the satellite coverage regions through a non-geostationary satellite communication system that includes a plurality of orbiting satellites, each satellite providing communication coverage within an assigned satellite coverage region;

creating a region assignment record at the land-based cellular communication system according to the assignment of the mobile stations to the terrestrial and satellite coverage areas;

tracking the positions of the plurality of orbiting satellites;

based on the position of the plurality of orbiting satellites, assigning a corresponding satellite overage region to each satellite;

creating a satellite coverage assignment record according to the assignment of the satellite coverage regions to the satellites; and

accessing the region assignment record and the satellite assignment record for assigning the mobile station to a satellite coverage region or a terrestrial coverage region in accordance with the location of the mobile station.

17. The method of claim 16, wherein the non-geostationary satellite communication system updates the region assignment record based on the location of a mobile communication system.

18. The method of claim 16, wherein the non-geostationary satellite communication system updates the region assignment record only when the mobile station is outside of the terrestrial coverage region.