Adapter that converts precision time protocol (PTP) to global positioning system (GPS)

• US 9,173,181 B1
• Filed: 07/24/2013
• Issued: 10/27/2015
• Est. Priority Date: 07/24/2013
• Status: Active Grant

• Current Assignee: T-Mobile Innovations LLC (Deutsche Telekom AG)
• Original Assignee: Sprint Communications Company LP (Deutsche Telekom AG)
• Inventors: Pearson, Timothy Hugh, Gan, Seng, Burford, Henry, English, Eric C.
• Primary Examiner(s): Sefcheck, Gregory
• Assistant Examiner(s): ULYSSE, JAEL M
• Application Number:
  US13/949,992
• Time in Patent Office: 825 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

A method and apparatus are provided for converting a precision time protocol (PTP) to a GPS signal. Enterprise versions of Femtocells are located within buildings and do not have access to a GPS signal directly from a GPS satellite. An adapter is provided that takes an available PTP and power over Ethernet (PoE) flow and converts the signal into a pseudo-GPS signal that acts as a timing input into the Femtocell. The pseudo-GPS signal is a GPS signal modulated at the L1 band frequency or 1575.42 megahertz, but does not have location data nor subframes 1, 2, or 3, as found in an ordinary GPS signal.

Claims

1. A method for relaying a global positioning system (GPS) signal using an Ethernet cable, comprising:

receiving a power over Ethernet (PoE) flow and a precision time protocol (PTP) at an adapter;

converting at least one of the PoE flow or the PTP to the GPS signal in the adapter; and

sending the GPS signal to a type of base station, wherein the GPS signal includes a L1 band frequency but does not include location data and subframes 1, 2, or 3.

2. The method of claim 1, wherein sending the GPS signal comprises sending the GPS signal to at least one of a femtocell or picocell.

3. An apparatus for creating a global positioning system (GPS) signal using an Ethernet cable, comprising:

a power over Ethernet (PoE) splitter that receives a PoE flow and a precision time protocol (PTP);

the PoE splitter that provides power to an oscillator and a conversion engine, and that provides the PTP to the conversion engine;

the oscillator that provides a frequency to the conversion engine; and

the conversion engine that provides the GPS signal, wherein the GPS signal is a pseudo-GPS signal, which is the GPS signal with a L1 band frequency but without location data and subframes 1, 2, or 3.

4. The apparatus of claim 3, wherein the conversion engine provides the GPS signal to a type of base station.

5. The apparatus of claim 4, wherein the type of base station is at least one of a femtocell or a picocell.

6. The apparatus of claim 5, wherein the conversion engine also provides an Ethernet output.

7. The apparatus of claim 3, wherein the conversion engine stabilizes a phase to the oscillator.

8. A conversion engine for converting an Ethernet signal to a GPS signal, comprising:

a precision time protocol (PTP) stack that receives a PTP over Ethernet;

the PTP stack that sends a one pulse per second signal and a 10.23 megahertz signal to a controller, and that provides an Ethernet output;

a phase lock loop that provides a corrective phase alignment from the controller to an oscillator;

the controller that receives a power signal, receives a frequency from the oscillator, and receives the one pulse per second signal and the 10.23 megahertz signal from the PTP stack; and

the controller that provides the GPS signal, wherein the GPS signal is a pseudo-GPS signal, which is the GPS signal with a L1 band frequency but without location data and subframes 1, 2, or 3.

9. The conversion engine of claim 8, wherein the controller includes a servo control of the oscillator, and pseudo L1 modulator.

10. The conversion engine of claim 9, wherein the servo control of the oscillator uses the one pulse per second signal and the frequency to stabilize the phase.

11. The conversion engine of claim 10, wherein the controller provides the GPS signal to a type of base station.

12. The conversion engine of claim 11, wherein the type of base station is at least one of a femtocell or a picocell.

13. The conversion engine of claim 8, wherein the PTP stack provides an Ethernet output.