LINK QUALITY MEASUREMENTS BASED ON DATA RATE AND RECEIVED POWER LEVEL

• US 20080108352A1
• Filed: 10/25/2007
• Published: 05/08/2008
• Est. Priority Date: 10/27/2006
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: Durand, Roger, Montemurro, Michael
• Granted Patent: US 8,126,454 B2
• Time in Patent Office: Days
• US Class Current: 455/437
• CPC Class Codes: H04L 43/0847 Transmission error
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 36/302 due to low signal strength

Abstract

A mobile station associated with a base station determines a measure of the quality of a communication link between the mobile station and the base station. The measure takes into account (a) RF power levels of signals received at the mobile station over the link and (b) an actual data rate of communications over the link. This measure of the quality of the link may be a factor in triggering the mobile station to initiate a handoff.

Claims

1. A method in a mobile station that is associated with a base station, the method comprising:

determining a measure of the quality of a link between the mobile station and the base station, where the measure takes into account radio frequency power levels of signals received at the mobile station over the link and an actual data rate of communications over the link.

2. The method of claim 1, further comprising:

determining whether to trigger the mobile station to initiate a handoff from the base station based, at least in part, on the measure of the quality of the link.

3. The method of claim 2, further comprising:

selecting as a target of the handoff a base station a link with which is expected to experience less interference than that which is experienced on the link between the mobile station and the base station with which the mobile station is associated.

4. The method of claim 1, further comprising:

determining based, at least in part, on the measure of the quality of the link whether to transfer to the link a communication session currently being carried over a different link between the mobile station and a different base station.

5. The method of claim 1, wherein determining the measure further comprises:

determining an expected data rate for communications over the link based on the power levels; and

comparing the expected data rate to the actual data rate.

6. The method of claim 1, wherein determining the measure further comprises:

determining an expected power level for communications over the link based on the actual data rate; and

comparing the expected power level to the power levels of signals received at the mobile station over the link.

7. The method of claim 1, further comprising:

using signal strength measurements of the signals as an indication of the power levels.

8. The method of claim 1, further comprising:

using received channel power indicator measurements of the signals as an indication of the power levels.

9. A mobile station comprising:

a wireless local area network communication interface through which the mobile station is able communicate with an access point over a communication link;

a processor coupled to the wireless local area network communication interface;

a memory coupled to the processor, the memory storing a link quality measurement module that, when executed by the processor, is arranged to determine a measure of the quality of the link, where the measure takes into account radio frequency power levels of signals received at the mobile station over the link via the wireless local area network communication interface and an actual data rate of communications over the link.

10. The mobile station of claim 9, wherein the memory stores a handoff application that, when executed by the processor, is arranged to determine when to initiate a handoff from the access point based, at least in part, on the measure of the quality of the link, and is arranged to control the wireless local area network communication interface accordingly.

11. The mobile station of claim 10, wherein the handoff application, when executed by the processor, is arranged to select as a target of the handoff a base station a link with which is expected to experience less interference than that which is experienced on the link between the mobile station and the access point.

12. The mobile station of claim 9, wherein the link quality measurement module, when executed by the processor, is arranged to determine the measure by determining an expected data rate for communications over the link based on the power levels and comparing the expected data rate to the actual data rate.

13. The mobile station of claim 9, wherein the link quality measurement module, when executed by the processor, is arranged to determine the measure by determining an expected power level for communications over the link based on the actual data rate and comparing the expected power level to the power levels of signals received at the mobile station over the link.

14. The mobile station of claim 9, wherein the link quality measurement module, when executed by the processor, is arranged to use signal strength measurements of the signals as an indication of the power levels.

15. The mobile station of claim 9, wherein the link quality measurement module, when executed by the processor, is arranged to use received channel power indicator measurements of the signals as an indication of the power levels.

16. A mobile station comprising:

a wireless local area network communication interface through which the mobile station is able communicate with an access point;

another wireless communication interface through which the mobile station is able to communicate with a base station over a communication link;

a processor coupled to the wireless local area network communication interface and to the other wireless communication interface;

a memory coupled to the processor, the memory storing a link quality measurement module that, when executed by the processor, is arranged to determine a measure of the quality of the link, where the measure takes into account radio frequency power levels of signals received at the mobile station over the link via the other wireless communication interface and an actual data rate of communications over the link.

17. The mobile station of claim 16, wherein the memory stores a handoff application module that, when executed by the processor, is arranged to determine when to initiate a handoff from the access point based, at least in part, on the measure of the quality of the link, and is arranged to control the wireless local area network communication interface accordingly.

18. The mobile station of claim 17, wherein the handoff application module, when executed by the processor, is arranged to determine based, at least in part, on the measure of the quality of the link whether to transfer to the link a communication session currently being carried over a different link between the mobile station and the access point.

19. The mobile station of claim 16, wherein the link quality measurement module, when executed by the processor, is arranged to determine the measure by determining an expected data rate for communications over the link based on the power levels and comparing the expected data rate to the actual data rate.

20. The mobile station of claim 16, wherein the link quality measurement module, when executed by the processor, is arranged to determine the measure by determining an expected power level for communications over the link based on the actual data rate and comparing the expected power level to the power levels of signals received at the mobile station over the link.

21. The mobile station of claim 16, wherein the link quality measurement module, when executed by the processor, is arranged to use signal strength measurements of the signals as an indication of the power levels.

22. The mobile station of claim 16, wherein the link quality measurement module, when executed by the processor, is arranged to use received channel power indicator measurements of the signals as an indication of the power levels.