Using Mobility Statistics to Enhance Telecommunications Handover

• US 20100120429A1
• Filed: 06/01/2009
• Published: 05/13/2010
• Est. Priority Date: 11/10/2008
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: KAZMI, Muhammad, Müller, Walter, Lindoff, Bengt, Susitaival, Riikka, Dimou, Konstantinos
• Granted Patent: US 8,229,434 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 36/302 due to low signal strength

Abstract

A method of operating a communications network (20) comprising a wireless terminal (30) which communicates with a network node (22) comprises using the wireless terminal (30) to perform measurements relative to plural cells of the network, and then using the wireless terminal (30) or the network node (22) to make a determination regarding an extent of connection of the wireless terminal to a best cell of the network. The method also comprises using the wireless terminal (30) or the network node (22) to select a mobility related parameter for the wireless terminal (30) in accordance with the determination.

Claims

1. A method of operating a communications network comprising a wireless terminal which communicates with a network node, the method comprising:

using the wireless terminal to perform measurements relative to plural cells of the network;

using the wireless terminal or the network node to make a determination regarding an extent of connection of the wireless terminal to a best cell of the network.

2. The method of claim 1, further comprising a wireless terminal reporting to the network node the determination regarding the extent of connection of the wireless terminal to a best cell of the network.

3. The method of claim 1, further comprising using the wireless terminal or the network node to select a mobility related parameter for the wireless terminal in accordance with the determination.

4. The method of claim 3, wherein using the wireless terminal or the network node to select a mobility related parameter for the wireless terminal in accordance with the determination comprises changing a value of a mobility management parameter and then changing a length of a discontinuous reception (DRX) cycle.

5. The method of claim 3, wherein the mobility related parameter comprises a parameter of a discontinuous reception (DRX) cycle.

6. The method of claim 5, further comprising the wireless terminal determining to progressively shorten length of the discontinuous reception (DRX) in accordance with the determination.

7. The method of claim 5, further comprising the network node configuring the wireless terminal with plural discontinuous reception (DRX) cycle values, and wherein the method further comprises the wireless terminal changing between the plural discontinuous reception (DRX) cycle values in accordance with the determination.

8. The method of claim 3, further comprising selecting two mobility management parameters for the wireless terminal in accordance with the determination, and wherein the two mobility management parameters comprise hysteresis of a signal value and time hysteresis before making a handover decision.

9. The method of claim 3, further comprising selecting a mobility management parameter as the mobility related parameter for the wireless terminal in accordance with the determination, and wherein the mobility management parameter comprises a length of an active cycle which defines one or more of (1) filter length of measurements;

and (2) periodicity with which measurements of signal strength received from a pilot signal is performed.

10. The method of claim 1, wherein making the determination of the extent of connection comprises determining whether a percentage of time that the wireless terminal is connected to a best cell of the network satisfies a threshold.

11. The method of claim 3, further comprising:

determining a traveling speed of the wireless terminal;

also selecting a value of the mobility management parameter dependent upon the traveling speed.

12. The method of claim 11, further comprising storing at the network node a table configured to map various traveling speeds to corresponding values of the mobility related parameter.

13. The method of claim 3, further comprising estimating the mobility related parameter at the wireless terminal in accordance with the determination.

14. The method of claim 13, further comprising the network node broadcasting differing mobility related parameter values corresponding to differing percentages of time values that the wireless terminal is not connected to the best cell.

15. A node of a communications network which communicates with a wireless terminal, the node comprising:

an interface with the wireless terminal by which the node receives measurements relative to plural cells of the network;

a computer configured to make a determination regarding an extent of connection of the wireless terminal to a best cell of the network

16. The method of claim 15, wherein the computer is configured to make the determination explicitly using the signal strength and/or signal quality measurements reported by the wireless terminal from plural cells of the network.

17. The method of claim 15, wherein the computer is configured to make the determination based on reports received from the wireless terminal wherein the said reports explicitly indicate the extent of connection of the wireless terminal to a best cell of the network

18. The node of claim 15, wherein the node is a base station node.

19. The node of claim 15, wherein the node is a radio network controller node.

20. The node of claim 15, further comprising a mobility related parameter input unit configured to select a mobility related parameter for the wireless terminal in accordance with the determination.

21. The node of claim 20, wherein the mobility related parameter is a mobility management parameter, and further comprising a handover unit configured to use the mobility management parameter to define when a handover decision is made.

22. The node of claim 20, wherein the mobility related parameter input unit is configured to select two mobility management parameters for the wireless terminal in accordance with the determination, and wherein the two mobility management parameters comprise hysteresis of a signal value and time hysteresis before making a handover decision.

23. The node of claim 20, wherein the mobility related parameter input unit is configured to change a mobility management parameter as the mobility related parameter, and then to change a length of a discontinuous reception (DRX) cycle.

24. The node of claim 20, wherein the mobility related parameter comprises a parameter of a discontinuous reception (DRX) cycle.

25. The node of claim 20, wherein the mobility related parameter input unit is further configured to provide the wireless terminal with plural discontinuous reception (DRX) cycle values so that the wireless terminal can change between the plural discontinuous reception (DRX) cycle values in accordance with the determination.

26. The node of claim 20, wherein the mobility related parameter is a mobility management parameter, and wherein the mobility management parameter comprises a length of an active cycle which defines one or more of (1) filter length of measurements;

and (2) periodicity with which measurements of signal strength received from a pilot signal is performed.

27. The node of claim 20, further comprising a wireless terminal speed determination unit configured to determine a traveling speed of the wireless terminal, and wherein the mobility related parameter input unit is configured to select a value of the mobility management parameter dependent upon the traveling speed.

28. A wireless terminal which communicates with a network node of a communications network, the wireless terminal comprising:

a measurement unit configured to perform measurements relative to plural cells of the network;

a computer configured to make a determination regarding an extent of connection of the wireless terminal to a best cell of the network.

29. The wireless terminal of claim 28, further comprising a mobility related parameter input unit configured to select a mobility related parameter for the wireless terminal in accordance with the determination.

30. The wireless terminal of claim 29, wherein the mobility related parameter is a mobility management parameter, and wherein the mobility related parameter input unit is further configured to select plural mobility management parameters for the wireless terminal in accordance with the determination, and wherein two mobility management parameters comprise hysteresis of a signal value and time hysteresis before making a handover decision.

31. The wireless terminal of claim 30, wherein the mobility related parameter is a mobility management parameter, and wherein the mobility related parameter input unit is configured to change a value of the MIMO mode and then to change a length of a discontinuous reception (DRX) cycle.

32. The wireless terminal of claim 29, wherein the mobility related parameter comprises a parameter of a discontinuous reception (DRX) cycle.

33. The wireless terminal of claim 32, wherein the mobility related parameter input unit is configured to progressively change length of the discontinuous reception (DRX) in accordance with the determination.

34. The wireless terminal of claim 32, wherein the wireless terminal is configured to receive plural discontinuous reception (DRX) cycle values from the network node, and wherein the mobility related parameter input unit is configured to change between the plural discontinuous reception (DRX) cycle values in accordance with the determination.

35. The wireless terminal of claim 29, wherein the mobility related parameter is a mobility management parameter, and wherein the mobility management parameter comprises a length of an active cycle which defines one or more of (1) filter length of measurements;

and (2) periodicity with which measurements of signal strength received from a pilot signal is performed.

36. The wireless terminal of claim 29, wherein the mobility related parameter input unit is configured to estimate the mobility related parameter at the wireless terminal in accordance with the determination.

37. The wireless terminal of claim 29, wherein when the wireless terminal is configured, when in idle mode, to make a random access request and, upon granting of the random access request, to transmit a measurement report to the network node regarding the extent of connection of the wireless terminal to the best cell of the network.