Satellite beam power backoff

• US 9,538,538 B2
• Filed: 09/24/2015
• Issued: 01/03/2017
• Est. Priority Date: 03/20/2015
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Zhang, Dan, Gurelli, Mehmet Izzet, Nagaraja, Sumeeth, Vassilovski, Dan, Determan, James Taylor, Marsh, Gene Wesley, Wu, Qiang
• Primary Examiner(s): TALUKDER, MD K
• Application Number:
  US14/864,758
• Publication Number:
  US 20160278063A1
• Time in Patent Office: 467 Days
• Field of Search: 455/12.1, 455/13.4, 455/13.2, 455/3.02, 455/427, 455/428
• US Class Current: 1/1
• CPC Class Codes: H04B 7/18543 for adaptation of transmission parameters, e.g. power control for detecting or preventing errors in the information received H04L1/00
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/0473 the resource being transmission power

Abstract

A method and apparatus for a non-geosynchronous orbit (NGSO) satellite to comply with equivalent power flux density (EPFD) limits are disclosed. The example implementations may allow a constellation of NGSO satellites to comply with EPFD limits without disabling beams transmitted from the NGSO satellites. The power level of one or more beams to be transmitted from the NGSO satellites may be dynamically adjusted according to a beam power back-off schedule. In some aspects, the beam power back-off schedule may specify beam power back-off values as a function of latitude on Earth, and may allow for maximum allowable power levels for beams transmitted from the NGSO satellites without violating any of the EPFD percentile limits.

Claims

1. A method of operating a non-geosynchronous orbit (NGSO) satellite to comply with equivalent power flux density (EPFD) limits, the method comprising:

for each of a number of selected locations on Earth;

determining a first cumulative distribution function (CDF) of EPFD levels associated with reception of a beam, to be transmitted from the NGSO satellite, at the selected location;

identifying a number of EPFD percentile limits that are violated by the first CDF of EPFD levels;

determining a second CDF of EPFD levels at the selected location based, at least in part, on the number of identified EPFD percentile limits; and

determining a power back-off value for the selected location based, at least in part, on the second CDF of EPFD levels;

compiling the determined power back-off values for the number of selected locations into a power back-off schedule; and

dynamically adjusting a power level of the beam to be transmitted from the NGSO satellite based on the power back-off schedule.

2. The method of claim 1, wherein the power back-off schedule represents the power back-off values as a function of latitude on Earth.

3. The method of claim 1, wherein the power back-off schedule comprises a vector including a number of components, each component indicating the power back-off value for a corresponding latitude on Earth.

4. The method of claim 1, wherein the second CDF of EPFD levels does not violate any of the number of identified EPFD percentile limits.

5. The method of claim 1, wherein determining the second CDF of EPFD levels comprises:

defining, for each of the number of identified EPFD percentile limits, a corresponding step function; and

modifying the first CDF of EPFD levels to include the defined step functions.

6. The method of claim 5, wherein each of the defined step functions is to avoid violating a corresponding one of the number of identified EPFD percentile limits, each of the identified EPFD percentile limits associated with a corresponding reference antenna dish size of a geosynchronous (GSO) earth station.

7. The method of claim 5, further comprising:

defining a number of EPFD intervals for the selected location based, at least in part, on the defined step functions; and

determining the power back-off value for the selected location based, at least in part, on the number of defined EPFD intervals.

8. The method of claim 7, wherein determining the power back-off value comprises:

simulating an operation of the NGSO satellite for a finite number of time ticks;

detecting violations of the EPFD percentile limits associated with each of the number of defined EPFD intervals; and

calculating the power back-off value based, at least in part, on the detected violations.

9. An apparatus for operating a non-geosynchronous orbit (NGSO) satellite to comply with equivalent power flux density (EPFD) limits, the apparatus comprising:

for each of a number of selected locations on Earth;

means for determining a first cumulative distribution function (CDF) of EPFD levels associated with reception of a beam, to be transmitted from the NGSO satellite, at the selected location;

means for identifying a number of EPFD percentile limits that are violated by the first CDF of EPFD levels;

means for determining a second CDF of EPFD levels at the selected location based, at least in part, on the number of identified EPFD percentile limits; and

means for determining a power back-off value for the selected location based, at least in part, on the second CDF of EPFD levels;

means for compiling the determined power back-off values for the number of selected locations into a power back-off schedule; and

means for dynamically adjusting a power level of the beam to be transmitted from the NGSO satellite based on the power back-off schedule.

10. The apparatus of claim 9, wherein the power back-off schedule represents the power back-off values as a function of latitude on Earth.

11. The apparatus of claim 9, wherein the power back-off schedule comprises a vector including a number of components, each component indicating the power back-off value for a corresponding latitude on Earth.

12. The apparatus of claim 9, wherein the second CDF of EPFD levels does not violate any of the number of identified EPFD percentile limits.

13. The apparatus of claim 9, wherein the means for determining the second CDF of EPFD levels is to:

define, for each of the number of identified EPFD percentile limits, a corresponding step function; and

modify the first CDF of EPFD levels to include the defined step functions.

14. The apparatus of claim 13, wherein each of the defined step functions is to avoid violating a corresponding one of the number of identified EPFD percentile limits, each of the identified EPFD percentile limits associated with a corresponding reference antenna dish size of a geosynchronous (GSO) earth station.

15. The apparatus of claim 13, further comprising:

means for defining a number of EPFD intervals for the selected location based, at least in part, on the defined step functions; and

means for determining the power back-off value for the selected location based, at least in part, on the number of defined EPFD intervals.

16. The apparatus of claim 15, wherein the means for determining the power back-off value is to:

simulate an operation of the NGSO satellite for a finite number of time ticks;

detect violations of the EPFD percentile limits associated with each of the number of defined EPFD intervals; and

calculate the power back-off value based, at least in part, on the detected violations.

17. An apparatus for operating a non-geosynchronous orbit (NGSO) satellite to comply with equivalent power flux density (EPFD) limits, the apparatus comprising:

one or more processors; and

a memory configured to store instructions that, when executed by the one or more processors, cause the apparatus to;

for each of a number of selected locations on Earth;

determine a first cumulative distribution function (CDF) of EPFD levels associated with reception of a beam, to be transmitted from the NGSO satellite, at the selected location;

identify a number of EPFD percentile limits that are violated by the first CDF of EPFD levels;

determine a second CDF of EPFD levels at the selected location based, at least in part, on the number of identified EPFD percentile limits; and

determine a power back-off value for the selected location based, at least in part, on the second CDF of EPFD levels;

compile the determined power back-off values for the number of selected locations into a power back-off schedule; and

dynamically adjust a power level of the beam to be transmitted from the NGSO satellite based on the power back-off schedule.

18. The apparatus of claim 17, wherein the power back-off schedule represents the power back-off values as a function of latitude on Earth.

19. The apparatus of claim 17, wherein the power back-off schedule comprises a vector including a number of components, each component indicating the power back-off value for a corresponding latitude on Earth.

20. The apparatus of claim 17, wherein execution of the instructions for determining the second CDF of EPFD levels causes the apparatus to:

define, for each of the number of identified EPFD percentile limits, a corresponding step function; and

modify the first CDF of EPFD levels to include the defined step functions.

21. The apparatus of claim 20, wherein each of the defined step functions is to avoid violating a corresponding one of the number of identified EPFD percentile limits, each of the identified EPFD percentile limits associated with a corresponding reference antenna dish size of a geosynchronous (GSO) earth station.

22. The apparatus of claim 20, wherein execution of the instructions causes the apparatus to further:

define a number of EPFD intervals for the selected location based, at least in part, on the defined step functions; and

determine the power back-off value for the selected location based, at least in part, on the number of defined EPFD intervals.

23. The apparatus of claim 22, wherein execution of the instructions for determining the power back-off value causes the apparatus to:

simulate an operation of the NGSO satellite for a finite number of time ticks;

detect violations of the EPFD percentile limits associated with each of the number of defined EPFD intervals; and

calculate the power back-off value based, at least in part, on the detected violations.

24. A non-transitory computer-readable medium storing instructions that, when executed by one or more processors of an apparatus, cause the apparatus to perform operations comprising:

for each of a number of selected locations on Earth;

determining a first cumulative distribution function (CDF) of EPFD levels associated with reception of a beam, to be transmitted from a non-geosynchronous orbit (NGSO) satellite, at the selected location;

identifying a number of EPFD percentile limits that are violated by the first CDF of EPFD levels;

determining a second CDF of EPFD levels at the selected location based, at least in part, on the number of identified EPFD percentile limits; and

determining a power back-off value for the selected location based, at least in part, on the second CDF of EPFD levels;

compiling the determined power back-off values for the number of selected locations into a power back-off schedule; and

dynamically adjusting a power level of the beam to be transmitted from the NGSO satellite based on the power back-off schedule.

25. The non-transitory computer-readable medium of claim 24, wherein the power back-off schedule represents the power back-off values as a function of latitude on Earth.

26. The non-transitory computer-readable medium of claim 24, wherein the power back-off schedule comprises a vector including a number of components, each component indicating the power back-off value for a corresponding latitude on Earth.

27. The non-transitory computer-readable medium of claim 24, wherein execution of the instructions for determining the second CDF of EPFD levels causes the apparatus to perform operations further comprising:

defining, for each of the number of identified EPFD percentile limits, a corresponding step function; and

modifying the first CDF of EPFD levels to include the defined step functions.

28. The non-transitory computer-readable medium of claim 27, wherein each of the defined step functions is to avoid violating a corresponding one of the number of identified EPFD percentile limits, each of the identified EPFD percentile limits associated with a corresponding reference antenna dish size of a geosynchronous (GSO) earth station.

29. The non-transitory computer-readable medium of claim 27, wherein execution of the instructions causes the apparatus to perform operations further comprising:

defining a number of EPFD intervals for the selected location based, at least in part, on the defined step functions; and

determining the power back-off value for the selected location based, at least in part, on the number of defined EPFD intervals.

30. The non-transitory computer-readable medium of claim 29, wherein execution of the instructions for determining the power back-off value causes the apparatus to perform operations further comprising:

simulating an operation of the NGSO satellite for a finite number of time ticks;

detecting violations of the EPFD percentile limits associated with each of the number of defined EPFD intervals; and

calculating the power back-off value based, at least in part, on the detected violations.