Method and arrangement of determining timing uncertainty

1. A method, comprising:

estimating, by an estimating circuit in a network node, uncertainty of a timing measurement used for positioning of a wireless device in a wireless communication system to obtain a timing measurement uncertainty estimate;

determining, by a first determining circuit in the network node, if a timing uncertainty reducing measurement is available;

in response to availability of the timing uncertainty reducing measurement, refining the timing measurement uncertainty estimate based on the timing uncertainty reducing measurement; and

in response to unavailability of the timing uncertainty reducing measurement:

initiating a positioning method;

obtaining, by an obtaining circuit in the network node, at least one of the timing uncertainty reducing measurement and a positioning result from the initiated positioning method; and

refining, by a second determining circuit in the network node, the timing measurement uncertainty estimate based on the obtained at least one of the timing uncertainty reducing measurement and the positioning result.

2. A method, comprising:

estimating, by an estimating circuit in a network node, uncertainty of a timing measurement used for positioning of a wireless device in a wireless communication system to obtain a timing measurement uncertainty estimate;

determining, by a first determining circuit in the network node, if a timing uncertainty reducing measurement is available;

in response to availability of the timing uncertainty reducing measurement, refining the timing measurement uncertainty estimate based the timing uncertainty reducing measurement; and

in response to unavailability of the timing uncertainty reducing measurement:

retrieving the timing uncertainty reducing measurement from another network node; and

refining, by a second determining circuit in the network node, the timing measurement uncertainty estimate based on the timing uncertainty reducing measurement.

3. The method according to claim 1 , further comprising:

comparing the timing measurement uncertainty estimate with a predefined threshold;

wherein determining if the timing uncertainty reducing measurement is available is performed in response to the timing measurement uncertainty estimate being larger than the predefined threshold.

4. The method according to claim 3 , wherein the predefined threshold is 5 microseconds which corresponds to a maximum absolute value within a range of −5 to +5 microseconds.

5. The method according to claim 1 , wherein the timing measurement uncertainty estimate is estimated based on a cell range.

6. The method according to claim 1 , wherein estimating the timing measurement uncertainty comprises:

estimating a first timing measurement uncertainty for a first cell and a second timing measurement uncertainty for a second cell; and

selecting a smaller of the estimated first and second timing measurement uncertainties as the estimated timing measurement uncertainty.

7. The method according to claim 1 , further comprising transmitting the refined timing measurement uncertainty in assistance data to the wireless device.

8. The method according to claim 1 , wherein the timing measurement comprises a reference signal time difference measurement or a time of arrival measurement.

9. The method according to claim 1 , wherein the timing measurement is usable for a time-difference-of-arrival-based positioning of the wireless device.

10. The method according to claim 1 , further comprising updating an uncertainty map based on the refined timing measurement uncertainty estimate, the uncertainty map associating a geographical area with a timing measurement uncertainty.

11. The method according to claim 1 , wherein the refined timing measurement uncertainty estimate is also based on a map associating a geographical area and the timing measurement.

12. The method according to claim 1 , wherein the refined timing measurement uncertainty estimate is also based on information comprising at least one of a cell sector information, an undesirable signal arrival direction, a cell range limit and a reference signal time difference limit.

13. The method according to claim 1 , wherein refining the timing measurement uncertainty estimate further comprises applying a shape conversion to convert a region of the refined timing measurement uncertainty estimate to a symmetric uncertainty range.

14. The method according to claim 1 , wherein refining the timing measurement uncertainty estimate further comprises performing a mathematical optimization based on a Lagrange multiplier approach to refine the timing measurement uncertainty estimate to be an uncertainty circle or ellipse.

15. A network node configured to be used in a wireless communication system, and configured to determine an uncertainty of a timing measurement used for positioning of a wireless device, the network node comprising:

an estimating circuit configured to estimate a timing measurement uncertainty;

a first determining circuit configured to determine if an uncertainty reducing measurement is available; and

a second determining circuit configured to determine the timing measurement uncertainty based on the estimated timing measurement uncertainty and the uncertainty reducing measurement, in response to availability of the uncertainty reducing measurement.

16. The network node according to claim 15 , further comprising:

an initiating circuit configured to initiate a positioning method in response to unavailability of the uncertainty reducing measurement; and

an obtaining circuit configured to obtain at least one of the uncertainty reducing measurement and a positioning result from the initiated positioning method;

wherein the second determining circuit is further configured to determine the timing measurement uncertainty based on the estimated timing measurement uncertainty, and the obtained at least one of the uncertainty reducing measurement and the positioning result.

17. The network node according to claim 15 , further comprising:

a retrieving circuit configured to retrieve an uncertainty reducing measurement from another network node in response to unavailability of the uncertainty reducing measurement;

wherein the second determining circuit is further configured to determine the timing measurement uncertainty based on the estimated timing measurement uncertainty and the retrieved uncertainty reducing measurement.

18. The network node according to claim 15 , further comprising:

a comparing circuit configured to compare the estimated timing measurement uncertainty with a predefined threshold;

wherein the first determining circuit is further configured to determine the timing measurement uncertainty in response to the estimated timing measurement uncertainty being larger than the predefined threshold.

19. The network node according to claim 15 , wherein the estimating circuit is configured to estimate the timing measurement uncertainty based on a cell range.

20. The network node according to claim 15 , wherein the estimating circuit is further configured to estimate a first timing measurement uncertainty for a first cell and a second timing measurement uncertainty for a second cell, and to select a smaller of the estimated first and second timing measurement uncertainties as the estimated timing uncertainty.

21. The network node according to claim 15 , further comprising a transmitter circuit configured to transmit the determined timing measurement uncertainty to the wireless device in assistance data.

22. The network node according to claim 15 , further comprising an updating circuit configured to update an uncertainty map based on the determined timing measurement uncertainty, the uncertainty map associating a geographical area with a timing measurement uncertainty.

23. The network node according to claim 15 , wherein the determining circuit is configured to determine the timing measurement uncertainty also based on a map associating a geographical area and the timing measurement.

24. The network node according to claim 15 , wherein the second determining circuit is configured to determine the timing measurement uncertainty also based on information comprising at least one of a cell sector information, an undesirable signal arrival direction, a cell range limit and a reference signal time difference limit.

25. The network node according to claim 15 , wherein the second determining circuit is further configured to apply a shape conversion to convert a region of the determined timing measurement uncertainty to a symmetric uncertainty range.

26. The network node according to claim 15 , wherein the second determining circuit is further configured to perform a mathematical optimization based on a Lagrange multiplier approach to determine the timing measurement uncertainty to be an uncertainty circle or ellipse.

27. The network node according to claim 15 , wherein the network node is a positioning node in a control plane or user plane architecture.