DETERMINING POSITIONING OF WIRELESS TERMINAL IN TELECOMMUNICATIONS NETWORK

• US 20100117898A1
• Filed: 04/12/2007
• Published: 05/13/2010
• Est. Priority Date: 04/12/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wigren, Torbjörn
• Granted Patent: US 8,654,010 B2
• Time in Patent Office: Days
• US Class Current: 342/357.430
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 5/0273 using multipath or indirect path propagation signals in position determination
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

In one of its aspects the technology concerns a method of determining a position of a wireless terminal in a radio access network using information of the travel time of radio waves between a base station and the wireless terminal, the travel time information being retrieved in a way consistent with SUPL positioning. The method comprises performing, at the wireless terminal, a time of arrival measurement for a respective downlink radio frame received from a node associated with a cell of a radio access network. The method thereafter uses the time of arrival measurement and an estimated time of downlink transmission from the node to make a determination of a distance between the wireless terminal and the node. The distance so determined can be used to generate an ellipsoid arc for describing a round trip time positioning of the wireless terminal. As an optional enhancement, the method further includes generating a thickness dimension of the ellipsoid arc, the thickness dimension of the ellipsoid arc reflecting clock uncertainty.

Claims

1. A wireless terminal (30) characterized by being adapted to perform a time of arrival measurement for a downlink radio frame received from a node (28) associated with a cell of a radio access network and to report the time of arrival measurement and a cell identifier of the cell to an entity (40) external to the radio access network without invoking any radio access network protocol.

2. The apparatus of claim 1, further comprising:

a universal reference acquisition unit (90) adapted to facilitate expression of the time of arrival measurement relative to a universal clock time, the universal clock time being maintained external to the radio access network;

a report unit (120) adapted to report transmit a universal clock expression of the time of arrival measurement to the entity external without invoking any radio access network protocol.

3. The apparatus of claim 2, wherein the universal reference acquisition unit (90) is further adapted to determine a geographical location of the wireless terminal;

and wherein the report unit (120) is further adapted to report the geographical location of the wireless terminal to the external entity (40).

4. The apparatus of claim 2, wherein the external entity is a Secure User Plane Location (SUPL) Location Platform (SLP) server.

5. The apparatus of claim 2, wherein the universal reference acquisition unit (90) includes capabilities of or interfaces to at least one of the following:

Global Positioning System (GPS), Assisted Global Positioning System (A-GPS), Galileo, Assisted Galileo (A-Galileo), or Assisted Global Navigation Satellite System (A-GNSS).

6. A server (40) which is external to a radio access network (23), characterized in that the server (40) is adapted to receive, from a wireless terminal (30) of the radio access network (23) and without invoking any radio access network protocol, plural time of arrival measurements for respective plural downlink radio frames received from a node (28) associated with a cell of a radio access network;

and wherein the server comprises means (100) for determining a distance between the wireless terminal (30) and the node (28), the distance being determined using the plural time of arrival measurements.

7. The server (40) of claim 6, further comprising:

an interface (102) for receiving the plural time of arrival measurements; and

wherein the means for determining the distance between the wireless terminal (30) and the node (28) uses a time of arrival measurement for a specific downlink radio reference frame and a time of downlink transmission from the node.

8. The apparatus of claim 7, wherein the distance determining means (100) is adapted to estimate the time of downlink transmission from the node (28) of the downlink radio frame and to use an estimated time of downlink transmission as the time of downlink transmission for determining the distance.

9. The apparatus of claim 8, wherein the distance determining means (100) is further adapted to determine the estimated time of downlink transmission using time of arrival information received from plural terminals of the cell.

10. The apparatus of claim 9, wherein the distance determining means (100) is further adapted to use a Kalman filter to determine the estimated time of downlink transmission using time of arrival information received from plural terminals of the cell.

11. The apparatus of claim 8, wherein the time of arrival measurements and the estimated time of downlink transmission are expressed relative to a universal clock time, the universal clock time being maintained external to the radio access network (23).

12. The apparatus of claim 11, the server (40) is adapted to receive, from the wireless terminal (30) of the radio access network (23) and without invoking any radio access network protocol, a value related to time elapsed since a previous fetching of the universal clock time.

13. The apparatus of claim 12, further comprising means for generating an ellipsoid arc for describing a round trip time positioning of the wireless terminal and for using the value related to time elapsed for generating a thickness dimension of the ellipsoid arc.

14. The apparatus of claim 6, wherein the terminal position determination unit (100) is further configured to generate an ellipsoid arc for describing a single trip time positioning of the wireless terminal.

15. The apparatus of claim 14, wherein the terminal position determination unit (100) is further configured to generate a thickness dimension of the ellipsoid arc, the thickness dimension of the ellipsoid arc reflecting clock uncertainty.

16. The apparatus of claim 6, wherein the server (40) is a Secure User Plane Location (SUPL) Location Platform (SLP) server.

17. The apparatus of claim 6, the server (40) is adapted to receive, from a wireless terminal (30) of the radio access network (23) and without invoking any radio access network protocol, a information describing a geographical location of the wireless terminal.

18. A method of determining position of a wireless terminal (30) in a radio access network (23), the method comprising:

performing, at the wireless terminal (30), a time of arrival measurement for a respective downlink radio frame received from a node (28) associated with a cell of a radio access network (23); and

thereafter,

using the time of arrival measurement and an estimated time of downlink transmission from the node to make a determination of a distance between the wireless terminal (30) and the node (28).

19. The method of claim 18, further comprising:

sending the time of arrival measurement from the wireless terminal (30) to a server (40) without invoking any radio access network protocol;

making the determination of the distance between the wireless terminal (30) and the node (28) at the server (40).

20. The method of claim 18, wherein the distance determining means (100) is further adapted to determine the estimated time of downlink transmission using time of arrival information received from plural terminals of the cell.

21. The method of claim 18, further comprising using a Kalman filter to determine the estimated time of downlink transmission, the Kalman filter using time of arrival information received from plural terminals of the cell.

22. The method of claim 18, further comprising determining the estimated time of downlink transmission from the node by:

using at least one time of arrival measurement;

using a reported geographical location of the wireless terminal (30); and

,

using a geographical location of the node (28).

23. The method of claim 22, further comprising:

expressing the plural time of arrival measurements in a universal clock time, the universal clock time being maintained external to the radio access network (23).

24. The method of claim 18, further comprising using the distance between the wireless terminal (30) and the node (28) to generate an ellipsoid arc for describing a single trip time positioning of the wireless terminal (30).

25. The apparatus of claim 24, further comprising generating a thickness dimension of the ellipsoid arc, the thickness dimension of the ellipsoid arc reflecting clock uncertainty.