Generating Accurate Time Assistance Data for An LTE Network

• US 20110279312A1
• Filed: 05/14/2010
• Published: 11/17/2011
• Est. Priority Date: 05/14/2010
• Status: Abandoned Application

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: Andrew LLC (CommScope Holding Company, Inc.)
• Inventors: Thomson, Martin Wyville
• Application Number:
  US12/780,496
• Publication Number:
  US 20110279312A1
• Time in Patent Office: Days
• US Class Current: 342/357.47
• CPC Class Codes: G01S 19/05 providing aiding data

Abstract

A system method for estimating Global Navigation Satellite System assistance data in a communications network. The method may comprise transmitting a location request from a mobility management entity to a location server, requesting a wireless device to transmit a first signal, and transmitting the first signal by the wireless device. A path delay estimate between the wireless device and location server may be determined as a function of an elapsed time for the request to the wireless to be received and as a function of an elapsed time for the transmitted first signal to be received. Satellite assistance data may then be determined as a function of current network time and the determined path delay estimate.

Claims

1. A method for estimating Global Navigation Satellite System (“

GNSS”

) assistance data in a communications network, the method comprising;

(a) transmitting a location request from a mobility management entity (“

MME”

) to a location server;

(b) requesting a wireless device to transmit a first signal;

(c) transmitting the first signal by the wireless device;

(d) determining a path delay estimate between the wireless device and location server as a function of an elapsed time for the request to the wireless device to be received and as a function of an elapsed time for the transmitted first signal to be received; and

(e) determining satellite assistance data as a function of current network time and the determined path delay estimate.

2. The method of claim 1 wherein the determined path delay estimate is determined by the following relationship:

(t_req−

t_rsp)/2

where t_req represents the elapsed time for the request to the wireless device to be received and t_rsp represents the elapsed time for the transmitted first signal to be received.

3. The method of claim 1 wherein the location server is an evolved serving mobile location center (“

E-SMLC”

).

4. The method of claim 1 wherein the step of determining a path delay estimate further comprises accounting for variations in path delay as a function of packet size.

5. The method of claim 1 further comprising the step of refining the path delay estimate as a function of acknowledgement messages transmitted from the server or wireless device.

6. The method of claim 1 wherein the communications network is a long term evolution (“

LTE”

) communications network.

7. The method of claim 1 wherein the first signal includes one or more parameters selected from the group consisting of:

transport channel parameters, physical channel parameters, Packet data Convergence Protocol parameters, Radio Link Control parameters, physical layer parameters, radio frequency parameters, measurement parameters, Inter-Radio Access Technology parameters, General parameters, Multimedia Broadcast Multicast Service related parameters, and combinations thereof.

8. The method of claim 1 further comprising the steps of:

(i) using the satellite assistance data to measure signals from one or more GNSS satellites;

(ii) determining a location of the wireless device as a function of the measured signals.

9. The method of claim 8 wherein the location of the wireless device is determined at the wireless device.

10. The method of claim 8 wherein the location of the wireless device is determined by the server using satellite measurements provided to the server from the wireless device.

11. The method of claim 1 wherein the first signal includes one or more parameters of GNSS assistance data selected from the group consisting of:

satellite ephemeris and clock parameters, ionosphere model, UTC model, differential GPS corrections, other GNSS assistance data, and combinations thereof.

12. A method for estimating a location of a wireless device in a communications network, the method comprising:

(a) transmitting a location request from the wireless device to a server;

(b) determining a path delay estimate between the server and the wireless device as a function of a redundant request transmitted by the server to the wireless device or as a function of messages provided in an acknowledgement sub-layer;

(c) determining satellite assistance data as a function of current network time and the determined path delay estimate;

(d) using the satellite assistance data to measure signals from one or more Global Navigation Satellite System (“

GNSS”

) satellites; and

(e) determining a location of the wireless device as a function of the measured signals.

13. The method of claim 12 where the server is an evolved serving mobile location center (“

E-SMLC”

).

14. The method of claim 12 wherein the communications network is a long term evolution (“

LTE”

) communications network.

15. The method of claim 12 wherein the step of transmitting a location request further comprises transmitting a location request to the server via a mobility management entity (“

MME”

).

16. A method for estimating a location of a wireless device in a communications network, the method comprising:

(a) transmitting a location request from the wireless device to server;

(b) determining a path delay estimate between the server and the wireless device as a function of a default value or as a function of a path delay estimate previously determined for a node serving the wireless device;

(c) determining satellite assistance data as a function of current network time and the determined path delay estimate;

(d) using the satellite assistance data to measure signals from one or more Global Navigation Satellite System (“

GNSS”

) satellites; and

(e) determining a location of the wireless device as a function of the measured signals.

17. The method of claim 16 where the server is an evolved serving mobile location center (“

E-SMLC”

).

18. The method of claim 16 wherein the communications network is a long term evolution (“

LTE”

) communications network.

19. The method of claim 16 wherein the step of transmitting a location request further comprises transmitting a location request to the server via a mobility management entity (“

MME”

).