Demand assigned spatial multiplexing in satellite communication systems

• US 6,625,129 B1
• Filed: 10/01/1999
• Issued: 09/23/2003
• Est. Priority Date: 10/01/1999
• Status: Expired due to Term

• Current Assignee: CDC Propriete Intellectuelle
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Wagner, Carl Myron, Olds, Keith A.
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US09/410,449
• Time in Patent Office: 1,453 Days
• Field of Search: 455/11.1, 455/12.1, 455/13.2, 455/427, 455/429, 455/430, 455/512, 455/517, 455/431, 370/316, 370/319, 370/320, 370/321, 370/323
• US Class Current: 370/316
• CPC Class Codes: H04B 7/18567 Arrangements for providing additional services to the basic mobile satellite telephony service
• CPC Class Codes: H04B 7/2041 Spot beam multiple access
• CPC Class Codes: H04B 7/2123 Variable assignment, e.g. demand assignment
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 4/00 Services specially adapted for wireless communication networks; Facilities therefor
• CPC Class Codes: H04W 74/00 Wireless channel access
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

The methods (300, 900, and 1200), and apparatus (140 and 800) of the present invention employ demand assigned spatial multiplexing in a satellite communication system (100) to efficiently accommodate varying demand for high data rate service while minimizing satellite antenna and radio system complexity in a ubiquitous coverage satellite system optimized for transporting packet data. In a preferred embodiment, the methods (300, 900, 1000 and 1200) and apparatus (140 and 800) of the present invention use a first set of signaling beams (210) to establish signaling uplinks and then direct traffic spot beams (220) at particular UE devices to support traffic uplinks in accordance with demand assigned multiple access (DAMA) parameters when and only when the UE devices have traffic data to transmit to a satellite. In a preferred embodiment, UE device (140) also executes a method (1200) that includes steps for determining appropriate steering angles for a servicing satellite (110) to use to direct a traffic spot beam (220) to the UE device'"'"'s location when the UE has traffic data to transmit.

Claims

1. A method for providing service in a satellite communication system having at least one satellite and at least one user equipment (UE) device, the method comprising the steps of:

projecting within a field of view (FOV) of a satellite a first set of antenna beams;

receiving from the UE device to the satellite, using an uplink signaling channel within a signaling frequency band associated with the first set of antenna beams, a demand assigned multiple access (DAMA) request to transmit traffic data to the satellite;

sending the UE device a DAMA response message; and

directing a spot beam from the satellite to establish a traffic uplink for transmitting the data traffic from the UE to the satellite in accordance with a set of parameters included in the DAMA response message, wherein the gain of the spot beam exceeds the gains of each of the first set of antenna beams, and wherein the set of traffic uplink channels operate in a radio frequency band at least ten times greater than the signaling frequency band.

2. The method as claimed in claim 1, wherein the DAMA request comprises a request for service including an identification of an amount of traffic data the UE desires to transmit to the satellite and an identification of the UE location in terms of satellite beam pointing angles calculated by the UE.

3. The method as claimed in claim 1, wherein the DAMA response message includes a time-slot assignment and a frequency channel assignment.

4. The method as claimed in claim 3, wherein immediately prior to a first assigned time-slot of the time-slot assignment, steering the spot beam to a location within the FOV of the satellite that includes the UE device and directing the spot beam to receive the data traffic from the UE in accordance with the frequency channel assignment.

5. The method as claimed in claim 1, wherein the first set of antenna gain beams support a set of signaling uplink channels operating at relatively low frequencies with relatively low data rates while the spot beam supports a set of traffic uplink channels operating at a relatively high frequency and with a relatively high data rate.

6. The method as claimed in claim 5, wherein the set of signaling uplink channels operate at a data rate at least one thousand times lower than a data rate at which the set of traffic uplink channels operate.

7. The method as claimed in claim 5, wherein the set of signaling uplink channels operate at a radio frequency band that is substantially the same as a radio frequency band at which the set of traffic uplink channels operate.

8. The method as claimed in claim 3, wherein immediately prior to a first assigned time-slot of the time-slot assignment, the satellite directs an assigned spot beam to establish an uplink to receive the data traffic in accordance with the frequency channel assignment.

9. The method as claimed in claim 8, further comprising the step of:

transmitting data traffic from the UE device to the satellite through an uplink channel associated with the assigned spot beam in accordance with the frequency channel assignment and the time-slot assignment.

10. The method as claimed in claim 1, wherein the DAMA response message comprises a single traffic time slot assignment.

11. The method as claimed in claim 1, wherein the DAMA response message comprises multiple traffic time slot assignments and multiple radio frequency channel assignments.

12. The method as claimed in claim 1, wherein the DAMA response message comprises multiple traffic time slot assignments and a single radio frequency channel assignment.

13. The method as claimed in claim 1, wherein the DAMA response message comprises a single radio frequency channel assignment, a time slot assignment, and a CDMA code assignment.

14. The method as claimed in claim 1, wherein the DAMA response message comprises a traffic time slot assignment and multiple radio frequency channel assignments.

15. An uplink antenna subsystem for use in a satellite of a satellite communication system, the uplink antenna subsystem comprising:

a signaling uplink subsystem for forming a set of uplink signaling beams associated with an uplink signaling channel within a signaling frequency band for receiving a demand assigned multiple access (DAMA) request to transmit traffic data from a user equipment (UE) device to the satellite; and

a traffic uplink subsystem In communication with the signaling uplink subsystem for forming a traffic spot beam associated with a traffic uplink and for directing the traffic spot beam to a location of a UE device in response to a request for service by the UE device, wherein the gain of the spot beam exceeds the gains of each of the uplink signaling beams and wherein the spot beam operates in a radio frequency band at least ten times greater than the signaling frequency band; and

a demand assigned multiple access (DAMA) processor for performing a DAMA assignment process to assign a resource associated with the satellite to support a UE transmit opportunity.

16. The uplink antenna subsystem as claimed in claim 15, wherein the signaling uplink system comprises a broad beam phased array antenna connected to a multiple beam former linked in communication with a beam steering processor for conforming the first set of uplink signaling beam to a radio resource plan determined by the DAMA processor.

17. The uplink antenna subsystem as claimed in claim 15, wherein the traffic uplink subsystem comprises a spot beam phased array antenna and a multiple beam former and steerer for directing a traffic spot beam to a UE device in accordance with a command from the DAMA processor.

18. The uplink antenna subsystem as claimed in claim 15, wherein the set of uplink signaling beams comprise a set of substantially fixed beams that cover substantially all of a field of view (FOV) of the satellite substantially simultaneously.

19. The uplink antenna subsystem as claimed in claim 15, wherein the uplink signaling beams comprise a set of beams, and wherein each beam of the set of relatively low gain beams is connected to a relatively low data rate random access channel.

20. The uplink antenna system as claimed in claim 15, wherein the traffic uplink spot beam comprises a beam operating at a relatively high frequency and with a relatively high data rate.

21. The uplink antenna subsystem as claimed in claim 15, wherein the traffic uplink subsystem directs the traffic spot beam to substantially any point within a field of view (FOV) of the satellite.

22. The uplink antenna subsystem as claimed in claim 15, wherein the traffic uplink subsystem directs the traffic spot beam to substantially any point within a portion of a field of view (FOV) of the satellite.

23. The uplink antenna subsystem as claimed in claim 15, wherein the traffic uplink subsystem forms multiple traffic spot beams covering substantially any point within a field of view (FOV) of the satellite.

24. The uplink antenna subsystem as claimed in claim 23, wherein only a subset of spot beams of the multiple traffic spot beams is available to carry uplink traffic, and wherein certain spot beams of the subset of spot beams are designated to carry traffic at a particular time based on user demand.

25. The uplink antenna subsystem as claimed in claim 15, wherein the DAMA assignment process comprises the steps of:

receiving in the DAMA processor the DAMA request;

determining that the satellite has appropriate resources available to assign a transmit opportunity to the UE within a relevant DAMA frame;

assigning the transmit opportunity to the UE; and

sending a DAMA response message including assigned parameters for the transmit opportunity to the UE.

26. The uplink antenna subsystem as claimed in claim 25, further comprising the step of:

assigning a service priority to the transmit opportunity.

27. The uplink antenna subsystem as claimed in claim 26, wherein the step of assigning a service priority to the transmit opportunity comprises the step of:

reading priority information associated with the DAMA request;

assigning the DAMA request to an appropriate priority queue;

selecting a highest priority queue containing a DAMA request; and

sending the DAMA request to the DAMA processor to receive a transmit opportunity assignment.