Multiple satellite repeater management system using frame error rate for diversity selection

• US 6,567,645 B1
• Filed: 08/28/2000
• Issued: 05/20/2003
• Est. Priority Date: 08/28/2000
• Status: Active Grant

• Current Assignee: Globalstar Incorporated
• Original Assignee: Globalstar Incorporated
• Inventors: Penwarden, Kent A., Wiedeman, Robert A., Monte, Paul A.
• Primary Examiner(s): Le, Thanh Cong
• Assistant Examiner(s): LEI, TSULEUN R
• Application Number:
  US09/649,326
• Time in Patent Office: 995 Days
• Field of Search: 455/12.1, 455/13.4, 455/67.1, 455/69, 455/427, 455/428, 455/430
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method for operating a mobile satellite telecommunications system has steps of (a) providing a user terminal that is operable to simultaneously receive a communication signal from a gateway via a plurality of satellites; and, (b) at the gateway, selectively transmitting the communication to one satellite or a plurality of satellites each having a coverage area that includes a current location of the user terminal. The step of selectively transmitting includes a step of considering a plurality of factors, including a current reception state of the user terminal, a current state of satellite power of at least one of the plurality of satellites, and a predicted required state of satellite power of the at least one satellite. The current reception state of the user terminal is indicated by a received signal quality indicator, which in the preferred embodiment is expressed as the Frame Error Rate (FER). If the value of the FER increases above a threshold level the number of selected satellites is increased, thereby increasing satellite diversity, and if the FER decreases below the threshold level the number of selected satellites is decreased, thereby decreasing satellite diversity. In addition, when a plurality of satellites are selected, the power through each selected satellite is controlled proportionally. The overall effect is conserve satellite power and optimize satellite power consumption, so as to satisfy future demand for the satellite'"'"'s circuits.

Claims

1. A method for operating a mobile satellite telecommunications system, comprising steps of:

providing a user terminal that is operable to simultaneously receive a communication signal from a ground station via a plurality of satellites; and

at the ground station, selectively transmitting the communication signal to one satellite or a plurality of satellites each having a coverage area that includes a current location of the user terminal;

wherein

said step of selectively transmitting comprises a step of considering a plurality of factors, comprising a current reception state of the user terminal, a current state of satellite power of at least one of the plurality of satellites, and a predicted required state of satellite power of the at least one satellite.

2. A method as in claim 1, wherein the current reception state of the user terminal is indicated by a received signal quality indicator.

3. A method as in claim 1, wherein the current reception state of the user terminal is indicated by a CDMA Frame Error Rate.

4. A method as in claim 1, wherein the current reception state of the user terminal is indicated by a Frame Error Rate (FER) that is determined in the user terminal from a forward link transmission, and further comprising a step of sending an indication of the FER to the ground station using a reverse link transmission.

5. A method as in claim 1, wherein the current reception state of the user terminal is indicated by a Frame Error Rate (FER) that is determined in the ground station from a reverse link transmission from the user terminal.

6. A method as in claim 1, wherein the current reception state of the user terminal is indicated by a value of a Frame Error Rate and a relationship of this value to previous values of the Frame Error Rate.

7. A method as in claim 1, wherein the current reception state of the user terminal is indicated by a Frame Error Rate (FER), wherein if the FER increases above a threshold level the number of selected satellites is increased, and wherein if the FER decreases below the threshold level the number of selected satellites is decreased.

8. A method as in claim 1, wherein the current reception state of the user terminal is indicated by a Frame Error Rate (FER), wherein if the FER increases above a threshold level, and the communication signal is being transmitted through a plurality of satellites, power is controlled proportionately on individual ones of said plurality of satellites to optimize the power resources of said plurality of satellites.

9. A mobile satellite telecommunications system, comprising:

a constellation of non-geosynchronous orbit satellites;

at least one gateway comprising a plurality of transmitters and receivers; and

at least one user terminal comprising a transmitter and a receiver comprising circuitry operable for simultaneously receiving a communication signal from said gateway via a plurality of said satellites;

wherein said gateway comprises a controller for selectively transmitting the communication signal to one of said satellites or to a plurality of said satellites, each having a coverage area that includes a current location of said user terminal; and

wherein

said gateway controller considers a plurality of factors for selecting which satellite or satellites to transmit the communication signal to, comprising a current reception state of said user terminal, a current state of satellite power of at least one of said plurality of satellites, and a predicted required state of satellite power of said at least one satellite.

10. A system as in claim 9, wherein the current reception state of said user terminal is indicated by a received signal quality indicator.

11. A system as in claim 9, wherein the current reception state of said user terminal is indicated by a Frame Error Rate.

12. A system as in claim 9, wherein the current reception state of said user terminal is indicated by a Frame Error Rate (FER) that is determined in said user terminal from a forward link transmission, wherein said indication is input to said user terminal transmitter and is sent to said gateway using a reverse link transmission.

13. A system as in claim 9, wherein the current reception state of said user terminal is indicated by a Frame Error Rate (FER) that is determined in said gateway from a reverse link transmission that is received from said user terminal.

14. A system as in claim 9, wherein the current reception state of said user terminal is indicated by a value of a Frame Error Rate and a relationship of this value to previous values of the Frame Error Rate.

15. A system as in claim 9, wherein the current reception state of the user terminal is indicated by a Frame Error Rate (FER), wherein if the FER increases above a threshold level the number of selected satellites is increased, and wherein if the FER decreases below the threshold level the number of selected satellites is decreased.

16. A system as in claim 9, wherein the current reception state of the user terminal is indicated by a Frame Error Rate (FER), wherein if the FER increases above a threshold level, and the communication signal is being transmitted through a plurality of satellites, power is controlled proportionately on individual ones of said plurality of satellites to optimize the power resources of said plurality of satellites.

17. A system as in claim 9, and further comprising a ground operations control center (GOCC) that is coupled to said gateway, and wherein at least said current state of satellite power and said predicted required state of satellite power are determined in said GOCC.

18. A system as in claim 9, wherein said receiver of said user terminal is comprised of a multi-finger RAKE receiver for simultaneously receiving said communication signal from said gateway via said plurality of satellites.