POSITIONING MEASUREMENTS AND CARRIER SWITCHING IN MULTI-CARRIER WIRELESS COMMUNICATION NETWORKS

• US 20120083278A1
• Filed: 10/05/2010
• Published: 04/05/2012
• Est. Priority Date: 10/01/2010
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Kazmi, Muhammad Ali, Siomina, Iana
• Granted Patent: US 10,034,205 B2
• Time in Patent Office: Days
• US Class Current: 455/440
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/322 by location data
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

In a multi-carrier wireless communication network, positioning-aware switching of a primary carrier from a first carrier to a second carrier for a UE is constrained to enable one or more positioning measurements to be performed. Either the selection of the second carrier, the timing of switching from the first to the second carrier, or both, are constrained to enable and enhance the positioning performance. The constraints may be operative at a serving node of the network, at a UE, or both. Further constraints may be applied to the network to enhance positioning performance. Carrier switching may be across Radio Access Technology (RAT), and the positioning constraints may include configuring or re-configuring a device to perform positioning measurements in measurement gaps (e.g., on a secondary carrier in LTE systems when Positioning Reference Signals are not transmitted on the primary carrier).

Claims

1. A method of positioning-aware carrier switching for User Equipment (UE), by a serving node of the UE in a multi-carrier wireless communication network, comprising:

assigning a first carrier as a primary carrier for the UE;

selecting a second carrier to be the primary carrier for the UE; and

switching the primary carrier for the UE from the first carrier to the second carrier;

wherein at least one of the selecting and switching steps is constrained so as to enable one or more positioning measurements to be performed.

2. The method of claim 1 wherein switching the primary carrier for the UE from the first carrier to the second carrier comprises treating the carrier switch as a handover procedure for an ongoing location service session.

3. The method of claim 1 wherein switching the primary carrier for the UE from the first carrier to the second carrier comprises:

ascertaining whether positioning measurements for the UE are ongoing; and

delaying switching the primary carrier for the UE from the first carrier to the second carrier until the positioning measurements are complete.

4. The method of claim 3 wherein ascertaining whether positioning measurements for the UE are ongoing comprises monitoring signaling messages between the UE and a location services network node.

5. The method of claim 3 wherein ascertaining whether positioning measurements for the UE are ongoing comprises requesting positioning measurement information from a location services network node.

6. The method of claim 3 wherein ascertaining whether positioning measurements for the UE are ongoing comprises requesting positioning measurement information from the UE.

7. The method of claim 3 wherein ascertaining whether positioning measurements for the UE are ongoing comprises obtaining an indication of the time positioning measurements began, and wherein delaying switching the primary carrier comprises:

switching the primary carrier if the positioning measurements have been ongoing for less than a predetermined duration; and

delaying switching the primary carrier until the positioning measurements are complete if the positioning measurements have been ongoing for more than the predetermined duration.

8. The method of claim 3 wherein delaying switching the primary carrier comprises delaying switching the primary carrier only if the requested positioning performance exceeds a predetermined performance threshold.

9. The method of claim 3 wherein delaying switching the primary carrier comprises delaying switching the primary carrier only if the UE matches a predetermined client type.

10. The method of claim 3 wherein delaying switching the primary carrier comprises delaying switching the primary carrier only if the location service class for which the positioning measurements are being preformed matches a predetermined location service class.

11. The method of claim 1 further comprising configuring measurement gaps on the second carrier to align the UE measurement occasions with transmissions of signals on the second carrier used for positioning measurements.

12. The method of claim 11 wherein the measurement gap information comprises a predetermined gap pattern.

13. The method of claim 11 wherein the measurement gap information comprises directing the UE not to use measurement gaps when Positioning Reference Signals are transmitted on the second carrier.

14. The method of claim 13 wherein configuring the UE to not use measurement gaps is in response to a predetermined rule.

15. The method of claim 1 wherein selecting a second carrier to be the primary carrier for the UE comprises selecting a second carrier that transmits Positioning Reference Signals (PRS).

16. The method of claim 15 further comprising selecting, from a plurality of potential primary carriers that transmit PRS, a second carrier that has the most favorable PRS configuration in the time or frequency domain.

17. The method of claim 15 comprising selecting, from a plurality of potential primary carriers that transmit PRS, a second carrier that has the most favorable radio conditions for the UE.

18. The method of claim 1 further comprising, if at least a first predetermined number of UEs are assigned the second carrier as a primary carrier, transmitting Positioning Reference Signals (PRS) on the second carrier.

19. The method of claim 1 further comprising, if fewer than a second predetermined number of UEs are assigned the second carrier as a primary carrier, ceasing the transmission of Positioning Reference Signals (PRS) on the second carrier.

20. The method of claim 1 further comprising:

transmitting Positioning Reference Signals (PRS) on the first and second carriers, the PRS transmissions staggered in time; and

switching the primary carrier for the UE to a carrier prior to a PRS transmission on that carrier.

21. The method of claim 1 wherein the serving node transmits the first and second carriers according to a first Radio Access Technology (RAT), and wherein the UE receives communication signals on a third carrier transmitted by a different serving node in a second RAT, further comprising:

configuring the UE to perform positioning measurements according to a positioning method selected in response to the primary carrier.

22. The method of claim 21 further comprising, when switching the primary carrier for the UE to the second RAT, configuring the UE to perform positioning measurements according to a positioning method selected in response to the second RAT.

23. The method of claim 21 further comprising sending a location services network node an indication of the RAT of the primary carrier for the UE.

24. A method of positioning-aware carrier switching by User Equipment (UE) operative in a multi-carrier wireless communication network, comprising:

receiving communication signals on a first carrier as a primary carrier;

performing one or more positioning measurements;

receiving an indication from a serving node that the primary carrier is to be switched from the first carrier to a second carrier; and

switching to the second carrier as the primary carrier while preserving the ongoing positioning measurements.

25. The method of claim 24 further comprising sending an indication of the primary carrier switch to a location services network node performing a positioning procedure for the UE using the positioning measurements.

26. The method of claim 24 further comprising sending an indication of the Radio Access Technology of the second carrier to a location services network node performing a positioning procedure for the UE using the positioning measurements.

27. The method of claim 24 further comprising receiving assistance data to perform positioning measurements on the second carrier.

28. The method of claim 24 wherein switching to the second carrier as the primary carrier while preserving the ongoing positioning measurements comprises preserving the ongoing positioning measurements only if Positioning Reference Signals are transmitted on the second carrier.

29. The method of claim 24 wherein switching to the second carrier as the primary carrier while preserving the ongoing positioning measurements comprises delaying the switch to the second carrier until the ongoing positioning measurements are complete.

30. The method of claim 29 further comprising transmitting to the serving node an indication that the switch to the second carrier is delayed.

31. The method of claim 30 further comprising transmitting to the serving node an estimate of the duration of the positioning measurement session.

32. The method of claim 24 further comprising performing a positioning procedure using the positioning measurements.

33. The method of claim 24 further comprising transmitting the positioning measurements to a location services network node to perform a positioning procedure to position the UE.

34. The method of claim 24 wherein the positioning measurement comprises Reference Signal Time Difference in Observed Time Difference of Arrival positioning method in LTE.

35. The method of claim 24 wherein the positioning measurement comprises UE receive-transmit time difference measurements in Enhanced Cell ID positioning method in LTE.

36. A serving node of a multi-carrier wireless communication network, comprising:

a transceiver operative to simultaneously transmit to User Equipment (UE) communication signals modulated onto two or more carriers, wherein a first carrier is designated as a primary carrier for a particular UE; and

a controller operative to control the transceiver, and further operative to select a second carrier to be the primary carrier for the UE, and to control the transceiver to switch the primary carrier for the UE from the first carrier to the second carrier;

wherein the controller is further operative to constrain at least one of the selecting and switching operations so as to enable one or more positioning measurements to be performed.

37. The node of claim 36 wherein switching the controller is operative to treat the carrier switch as a handover procedure for an ongoing location service session.

38. The node of claim 36 wherein the controller is operative to switch the primary carrier for the UE from the first carrier to the second carrier by:

ascertaining whether positioning measurements for the UE are ongoing; and

delaying switching the primary carrier for the UE from the first carrier to the second carrier until the positioning measurements are complete.

39. The node of claim 38 wherein ascertaining whether positioning measurements for the UE are ongoing comprises monitoring signaling messages between the UE and a location services network node.

40. The node of claim 38 wherein ascertaining whether positioning measurements for the UE are ongoing comprises requesting positioning procedure information from a location services network node.

41. The node of claim 38 wherein ascertaining whether positioning measurements for the UE are ongoing comprises requesting positioning procedure information from the UE.

42. The node of claim 38 wherein ascertaining whether positioning measurements for the UE are ongoing comprises obtaining an indication of the time a positioning measurements began, and wherein delaying switching the primary carrier comprises:

switching the primary carrier if the positioning measurements have been ongoing for less than a predetermined duration; and

delaying switching the primary carrier until the positioning measurements are complete if the positioning measurements have been ongoing for more than the predetermined duration.

43. The node of claim 38 wherein delaying switching the primary carrier comprises delaying switching the primary carrier only if the requested positioning Quality of Service (QoS) exceeds a predetermined QoS threshold.

44. The node of claim 36 wherein the controller is operative to configure measurement gap information for the UE to align with positioning data transmissions on the second carrier.

45. The node of claim 44 wherein the measurement gap information comprises a predetermined gap pattern.

46. The node of claim 44 wherein the measurement gap information comprises directing the UE not to use measurement gaps when Positioning Reference Signals are transmitted on the second carrier.

47. The node of claim 36 wherein the controller is operative to select a second carrier to be the primary carrier for the UE by selecting a second carrier that transmits Positioning Reference Signals (PRS).

48. The node of claim 47 wherein the controller is operative to select, from a plurality of potential primary carriers that transmit PRS, a second carrier that has the most favorable PRS configuration in the time or frequency domain.

49. The node of claim 47 wherein the controller is operative to select, from a plurality of potential primary carriers that transmit PRS, a second carrier that has the most favorable radio conditions for the UE.

50. The node of claim 36 wherein the controller is further operative to transmit Positioning Reference Signals (PRS) on the second carrier if at least a first predetermined number of UEs are assigned the second carrier as a primary carrier.

51. The node of claim 36 wherein the controller is further operative to cease the transmission of Positioning Reference Signals (PRS) on the second carrier if fewer than a second predetermined number of UEs are assigned the second carrier as a primary carrier.

52. The node of claim 36 wherein the controller is further operative to:

transmit Positioning Reference Signals (PRS) on the first and second carriers, the PRS transmissions staggered in time; and

switch the primary carrier for the UE to a carrier prior to a PRS transmission on that carrier.

53. The node of claim 36 wherein the controller is operative to transmit the first and second carriers according to a first Radio Access Technology (RAT), and wherein the UE receives communication signals on a third carrier transmitted by a different serving node in a second RAT, and wherein the controller is further operative to:

configure the UE to perform positioning measurements according to a positioning node selected in response to the primary carrier.

54. The node of claim 53 wherein the controller is further operative to configure the UE to perform positioning measurements according to a positioning method selected in response to the second RAT, when switching the primary carrier for the UE to the second RAT.

55. The node of claim 53 wherein the controller is further operative to send to a location services network node an indication of the RAT of the primary carrier for the UE.

56. A User Equipment (UE) operative in a multi-carrier wireless communication network, comprising:

a transceiver operative to simultaneously receive from a network node communication signals modulated onto two or more carriers, wherein a first carrier is designated as a primary carrier for the UE;

a position measurement function in data communications relationship to the transceiver and operative to perform positioning measurements used in ascertaining a geographic location of the UE; and

a controller operative to control the transceiver and position measurement function, and further operative to switch from the first carrier to a second carrier as the primary carrier in response to signals received from the network node, while preserving ongoing positioning measurements.

57. The method of claim 56 wherein the controller is further operative to send an indication of the primary carrier switch to the location services network node.

58. The method of claim 57 wherein the controller is further operative to receive assistance data to perform positioning measurements on the second carrier.

59. The method of claim 58 wherein the assistance data include measurement gap re-configuration data.

60. The method of claim 56 wherein the controller is further operative to use a pre-defined measurement gap pattern to perform positioning measurements.

61. The method of claim 56 wherein the controller is further operative to apply a predetermined rule to not use measurement gaps when Positioning Reference Signals are transmitted on the second carrier.

62. The method of claim 56 wherein the controller is operative to preserve the ongoing positioning measurements when switching to the second carrier as the primary carrier only if Positioning Reference Signals are transmitted on the second carrier.

63. The method of claim 56 wherein the controller is operative to delay the switch to the second carrier until the ongoing positioning measurements are complete.

64. The method of claim 63 wherein the controller is further operative to transmit to the serving node an indication that the switch to the second carrier is delayed.

65. The method of claim 63 wherein the controller is further operative to transmit to the serving node an estimate of the duration of the positioning measurements.