MULTIDIMENSIONAL ALGORITHM FOR ROAMING

• US 20150098392A1
• Filed: 10/08/2013
• Published: 04/09/2015
• Est. Priority Date: 10/08/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Homchaudhuri, Sandip, Du, Shu, Husted, Paul, Kumar, Sumeet, Rao, Sohani Ganesh
• Granted Patent: US 9,326,230 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 40/244 using a network of reference devices, e.g. beaconing
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Methods, devices, and apparatuses are described for wireless communications using a multidimensional algorithm for roaming. In one aspect, an initial set of candidate access points (APs) is produced by a station using a roaming scan. The initial set may be identified based at least in part on an initial metric (e.g., beacon signal strength). A probe signal may be transmitted by the station to at least one of the candidate APs in the initial set and information may be received in response to the probe signals. The station may then identify a reduced set from the initial set based at least in part on the received information, where the reduced set is used to select a target AP. At least one additional metric may be identified and the probe signal may be configured to obtain information corresponding to the additional metrics. This information may be used by the station to select the candidate APs in the reduced set.

Claims

1. A method for wireless communications, comprising:

identifying an initial set of candidate access points produced by a roaming scan, the initial set being identified based at least in part on an initial metric;

transmitting a probe signal to at least one of the initial set of candidate access points;

receiving information responsive to the transmitted probe signals; and

identifying a reduced set from the initial set, the reduced set being identified based at least in part on the received information and being used to select a target access point.

2. The method of claim 1, further comprising identifying at least one additional metric, the probe signal being configured to obtain information corresponding to the at least one additional metric, wherein the at least one additional metric comprises one or more of:

a data throughput;

a power consumption rate;

a data packet power level;

an acknowledgment packet power level;

an access point line of sight range;

a transmit diversity;

a network loading;

a low-power feature;

a transmit beamforming parameter;

a multi-user multiple-input multiple-output (MIMO) parameter;

a channel delay spread parameter;

a blocker presence and magnitude parameter;

a Space Time Block Coding (STBC) and/or Low-Density Parity-Check (LDPC) capability parameter; and

an angle-of-arrival variation.

3. The method of claim 1, wherein identifying the reduced set from the initial set comprises:

identifying at least one additional metric based at least in part on the received information; and

at least one from the group consisting of;

selecting candidate access points from the initial set for which the at least one additional metric is greater than a threshold value; and

discarding candidate access points from the initial set for which the at least one additional metric is less than a threshold value.

4. The method of claim 1, wherein identifying the reduced set from the initial set comprises:

identifying additional metrics based at least in part on the received information;

combining the additional metrics; and

selecting candidate access points from the initial set for which the combined additional metrics are greater than a threshold value.

5. The method of claim 4, wherein combining the additional metrics comprises:

applying weighted factors to the additional metrics; and

adapting the weighted additional metrics with respect to one of the additional metrics.

6. The method of claim 1, wherein the initial metric comprises a beacon power level.

7. The method of claim 1, further comprising triggering the roaming scan during an idle associated mode or an active traffic mode based at least in part on a metric different from the initial metric.

8. The method of claim 1, further comprising triggering the roaming scan when the initial metric is greater than a threshold value and at least one additional metric is less than a threshold value.

9. The method of claim 1, further comprising adapting a threshold value used with the initial metric to identify the initial set.

10. A device for wireless communications, comprising:

a roaming module configured to identify an initial set of candidate access points produced by a roaming scan, the initial set being identified based at least in part on an initial metric;

a transmitter configured to transmit a probe signal to at least one of the initial set of candidate access points; and

a receiver configured to receive information responsive to the transmitted probe signals, wherein the roaming module is further configured to identify a reduced set from the initial set based at least in part on the received information and to use to the reduced set to select a target access point.

11. The device of claim 10, wherein the roaming module is further configured to:

identify at least one additional metric; and

configure the probe signal to obtain information corresponding to the at least one additional metric, wherein the at least one additional metric comprises one or more of;

a data throughput;

a power consumption rate;

a data packet power level;

an acknowledgment packet power level;

an access point line of sight range;

a transmit diversity;

a network loading;

a low-power feature;

a transmit beamforming parameter;

a multi-user multiple-input multiple-output (MIMO) parameter;

a channel delay spread parameter;

a blocker presence and magnitude parameter;

a Space Time Block Coding (STBC) and/or Low-Density Parity-Check (LDPC) capability parameter; and

an angle-of-arrival variation.

12. The device of claim 10, wherein the roaming module is configured to identify the reduced set from the initial set by being configured to:

identify at least one additional metric based at least in part on the received information; and

select candidate access points from the initial set for which the at least one additional metric is greater than a threshold value.

13. The device of claim 10, wherein the roaming module is configured to identify the reduced set from the initial set by being configured to:

identify additional metrics based at least in part on the received information;

combine the additional metrics; and

select candidate access points from the initial set for which the combined additional metrics are greater than a threshold value.

14. The device of claim 13, wherein the roaming module is configured to combine the additional metrics by being configured to:

apply weighted factors to the additional metrics; and

adapt the weighted additional metrics with respect to one of the additional metrics.

15. The device of claim 10, wherein the initial metric comprises a beacon power level.

16. The device of claim 10, wherein the roaming module is further configured to perform at least one from a group consisting of:

trigger the roaming scan during an idle associated mode or an active traffic mode based at least in part a metric different from the initial metric; and

trigger the roaming scan when the initial metric is greater than a threshold value and at least one additional metric is less than a threshold value.

17. An apparatus for wireless communications, comprising:

means for identifying an initial set of candidate access points produced by a roaming scan, the initial set being identified based at least in part on an initial metric;

means for transmitting a probe signal to at least one of the initial set of candidate access points;

means for receiving information responsive to the transmitted probe signals; and

means for identifying a reduced set from the initial set, the reduced set being identified based at least in part on the received information and being used to select a target access point.

18. The apparatus of claim 17, further comprising means for identifying at least one additional metric, the probe signal being configured to obtain information corresponding to the at least one additional metric.

19. The apparatus of claim 18, wherein the at least one additional metric comprises one or more of:

a data throughput;

a power consumption rate;

a data packet power level;

an acknowledgment packet power level;

an access point line of sight range;

a transmit diversity;

a network loading;

a low-power feature;

a transmit beamforming parameter;

a multi-user multiple-input multiple-output (MIMO) parameter;

a channel delay spread parameter;

a blocker presence and magnitude parameter;

a Space Time Block Coding (STBC) and/or Low-Density Parity-Check (LDPC) capability parameter; and

an angle-of-arrival variation.

20. The apparatus of claim 17, wherein the means for identifying the reduced set from the initial set comprises:

means for identifying at least one additional metric based at least in part on the received information; and

means for selecting candidate access points from the initial set for which the at least one additional metric is greater than a threshold value.

21. The apparatus of claim 17, wherein the means for identifying the reduced set from the initial set comprises:

means for identifying additional metrics based at least in part on the received information;

means for combining the additional metrics; and

means for selecting candidate access points from the initial set for which the combined additional metrics are greater than a threshold value.

22. The apparatus of claim 21, wherein the means for combining the additional metrics comprises:

means for applying weighted factors to the additional metrics; and

means for optimizing the weighted additional metrics with respect to one of the additional metrics.

23. The apparatus of claim 17, wherein the initial metric comprises a beacon power level.

24. The apparatus of claim 17, further comprising means for triggering the roaming scan during an idle associated mode or an active traffic mode based at least in part on a metric different from the initial metric.

25. The apparatus of claim 17, further comprising means for triggering the roaming scan when the initial metric is greater than a threshold value and at least one additional metric is less than a threshold value.

26. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing at least one computer to identify an initial set of candidate access points produced by a roaming scan, the initial set being identified based at least in part on an initial metric;

code for causing the at least one computer to transmit a probe signal to at least one of the initial set of candidate access points;

code for causing the at least one computer to receive information responsive to the transmitted probe signals; and

code for causing the at least one computer to identify a reduced set from the initial set, the reduced set being identified based at least in part on the received information and being used to select a target access point.

27. The computer program product of claim 26, wherein the non-transitory computer-readable medium further comprises code for causing the at least one computer to identify at least one additional metric, the probe signal being configured to obtain information corresponding to the at least one additional metric, wherein the at least one additional metric comprises one or more of:

a data throughput;

a power consumption rate;

a data packet power level;

an acknowledgment packet power level;

an access point line of sight range;

a transmit diversity;

a network loading;

a low-power feature;

a transmit beamforming parameter;

a multi-user multiple-input multiple-output (MIMO) parameter;

a channel delay spread parameter;

a blocker presence and magnitude parameter;

a Space Time Block Coding (STBC) and/or Low-Density Parity-Check (LDPC) capability parameter; and

an angle-of-arrival variation.

28. The computer program product of claim 26, wherein the code for causing the at least one computer to identify the reduced set from the initial set comprises:

code for causing the at least one computer to identify at least one additional metric based at least in part on the received information; and

at least one from the group consisting of;

code for causing the at least one computer to select candidate access points from the initial set for which the at least one additional metric is greater than a threshold value; and

code for causing the at least one computer to combine the additional metrics and causing the at least one computer to select candidate access points from the initial set for which the combined additional metrics are greater than a threshold value.

29. The computer program product of claim 28, wherein the code for causing the at least one computer to combine the additional metrics comprises:

code for causing the at least one computer to apply weighted factors to the additional metrics; and

code for causing the at least one computer to adapt the weighted additional metrics with respect to one of the additional metrics.

30. The computer program product of claim 26, wherein the non-transitory computer-readable medium further comprises at least one from the group consisting of:

code for causing the at least one computer to trigger the roaming scan during an idle associated mode or an active traffic mode based at least in part on a metric different from the initial metric; and

code for causing the at least one computer to trigger the roaming scan when the initial metric is greater than a threshold value and at least one additional metric is less than a threshold value.