US7082301B2
Expired / Lapsed
US
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Method and system for triggering handoff of a call between networks
Assignee: Cisco Technology Inc
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Filing: 2003-09-12
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Granted: 2006-07-25
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Expires: 2023-09-12
Abstract
Abstract A method for handing off a call between networks includes monitoring a quality of a first link between a mobile station and a wireless local area network (WLAN) when the mobile station is actively connected with the WLAN on a call and monitoring a quality of a second link between the mobile station and a cellular network when the mobile station is actively connected with the WLAN on the call. The method also includes handing off the call from the WLAN to the cellular network when the quality of the first link is less than a handoff trigger threshold for a drop count duration and when the quality of the second link is greater than a minimum cellular link quality threshold.
Inventors
- 👤 Ramanathan T. Jagadeesan
- 👤 Bich Tu Nguyen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:31
CPC Classifications
H; H04; H04W; H04W36/00; H04W36/14; H04W36/144; H04W36/24; H04W36/30; H04W36/302; H04W84/00; H04W84/02; H04W84/10; H04W84/12; H04W88/00; H04W88/02; H04W88/06; H04W92/00; H04W92/02
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
119 words
A method for handing off a call between networks, comprising: monitoring a quality of a first link between a mobile station and a wireless local area network (WLAN) when the mobile station is actively connected with the WLAN on a call; monitoring a quality of a second link between the mobile station and a cellular network when the mobile station is actively connected with the WLAN on the call; and triggering a handoff of the call from the WLAN to the cellular network when the quality of the first link is less than a handoff trigger threshold for a drop count duration and when the quality of the second link is greater than a minimum cellular link quality threshold.
Claim 2
Independent Claim
119 words
A method for handing off a call between networks, comprising: monitoring a quality of a first link between a mobile station and a wireless local area network (WLAN) when the mobile station is actively connected with the WLAN on a call; monitoring a quality of a second link between the mobile station and a cellular network when the mobile station is actively connected with the WLAN on the call; and triggering a handoff of the call from the WLAN to the cellular network when the quality of the first link is less than a handoff trigger threshold for a drop count duration and when the quality of the second link is greater than a minimum cellular link quality threshold.
Claim 3
Dependent Claim
73 words
The method of claim 1 , further comprising: monitoring the quality of the first link between the mobile station and the WLAN when the mobile station is actively connected with the cellular network on the call; and triggering a handoff of the call from the cellular network to the WLAN when the quality of the first link is greater than the handoff trigger threshold plus a hysteresis margin for a pick-up count duration.
Claim 4
Dependent Claim
19 words
The method of claim 2 , further comprising tuning a control to change a value of the hysteresis margin.
Claim 5
Dependent Claim
20 words
The method of claim 2 , further comprising tuning a control to change a value of the drop count duration.
Claim 6
Dependent Claim
14 words
The method of claim 1 , wherein the WLAN communicates using IEEE 802.11 protocol.
Claim 7
Dependent Claim
26 words
The method of claim 1 , wherein monitoring a quality of a first link between a mobile station and a WLAN comprises monitoring a WLAN metric.
Claim 8
Dependent Claim
44 words
The method of claim 6 , wherein the WLAN metric comprises one of a group of metrics consisting of a received signal strength, a signal to noise ration, a signal quality, an error vector magnitude, a bit error rate and a packet error rate.
Claim 9
Dependent Claim
16 words
The method of claim 6 , wherein the WLAN metric comprises a quality of service parameter.
Claim 10
Dependent Claim
21 words
The method of claim 8 , wherein the quality of service parameter comprises packet jitter, delay or WLAN collision error rate.
Claim 11
Dependent Claim
28 words
The method of claim 1 , wherein monitoring a quality of a first link between a mobile station and a WLAN comprises monitoring a plurality of WLAN metrics.
Claim 12
Dependent Claim
23 words
The method of claim 10 , wherein monitoring a plurality of WLAN metrics comprises determining a vector comprising a plurality of WLAN metrics.
Claim 13
Dependent Claim
27 words
The method of claim 10 , wherein monitoring a plurality of WLAN metrics comprises determining a scalar value comprising a function of a plurality of WLAN metrics.
Claim 14
Dependent Claim
27 words
The method of claim 1 , wherein monitoring a quality of a second link between the mobile station and a cellular network comprises monitoring a cellular metric.
Claim 15
Dependent Claim
32 words
The method of claim 13 , wherein the cellular metric comprises one of a group of metrics consisting of a received signal strength, a bit error rate and a frame error rate.
Claim 16
Dependent Claim
29 words
The method of claim 1 , wherein the drop count duration comprises a first number of samples out of a second number of samples taken at a sample interval.
Claim 17
Dependent Claim
13 words
The method of claim 15 , wherein the sample interval comprises 250 milliseconds.
Claim 18
Independent Claim
127 words
A system for handing off a call between networks, comprising a mobile station comprising a controller operable to: monitor a quality of a first link between the mobile station and a wireless local area network (WLAN) when the mobile station is actively connected with the WLAN on a call; monitor a quality of a second link between the mobile station and a cellular network when the mobile station is actively connected with the WLAN on the call; and trigger a handoff of the call from the WLAN to the cellular network when the quality of the first link is less than a handoff trigger threshold for a drop count duration and when the quality of the second link is greater than a minimum cellular link quality threshold.
Claim 19
Independent Claim
127 words
A system for handing off a call between networks, comprising a mobile station comprising a controller operable to: monitor a quality of a first link between the mobile station and a wireless local area network (WLAN) when the mobile station is actively connected with the WLAN on a call; monitor a quality of a second link between the mobile station and a cellular network when the mobile station is actively connected with the WLAN on the call; and trigger a handoff of the call from the WLAN to the cellular network when the quality of the first link is less than a handoff trigger threshold for a drop count duration and when the quality of the second link is greater than a minimum cellular link quality threshold.
Claim 20
Dependent Claim
78 words
The system of claim 17 , wherein the controller is further operable to: monitor the quality of the first link between the mobile station and the WLAN when the mobile station is actively connected with the cellular network on the call; and trigger a handoff of the call from the cellular network to the WLAN when the quality of the first link is greater than the handoff trigger threshold plus a hysteresis margin for a pick-up count duration.
Claim 21
Dependent Claim
25 words
The system of claim 18 , wherein the mobile station further comprises a tuning knob operable to tune the hysteresis margin to change its value.
Claim 22
Dependent Claim
14 words
The system of claim 17 , wherein the WLAIN communicates using IEEE 802.11 protocol.
Claim 23
Dependent Claim
34 words
The system of claim 17 , wherein a controller operable to monitor a quality of a first link between a mobile station and a WLAN comprises a controller operable to monitor a WLAN metric.
Claim 24
Dependent Claim
44 words
The system of claim 21 , wherein the WLAN metric comprises one of a group of metrics consisting of a received signal strength, a signal to noise ration, a signal quality, an error vector magnitude, a bit error rate and a packet error rate.
Claim 25
Dependent Claim
16 words
The system of claim 21 , wherein the WLAN metric comprises a quality of service parameter.
Claim 26
Dependent Claim
21 words
The system of claim 23 , wherein the quality of service parameter comprises packet jitter, delay or WLAN collision error rate.
Claim 27
Dependent Claim
36 words
The system of claim 17 , wherein a controller operable to monitor a quality of a first link between a mobile station and a WLAN comprises a controller operable to monitor a plurality of WLAN metrics.
Claim 28
Dependent Claim
31 words
The system of claim 25 , wherein a controller operable to monitor a plurality of WLAN metrics comprises a controller operable to determine a vector comprising a plurality of WLAN metrics.
Claim 29
Dependent Claim
35 words
The system of claim 25 , wherein a controller operable to monitor a plurality of WLAN metrics comprises a controller operable to determine a scalar value comprising a function of a plurality of WLAN metrics.
Claim 30
Dependent Claim
35 words
The system of claim 17 , wherein a controller operable to monitor a quality of a second link between the mobile station and a cellular network comprises a controller operable to monitor a cellular metric.
Claim 31
Dependent Claim
32 words
The system of claim 28 , wherein the cellular metric comprises one of a group of metrics consisting of a received signal strength, a bit error rate and a frame error rate.
Claim 32
Dependent Claim
29 words
The system of claim 17 , wherein the drop count duration comprises a first number of samples out of a second number of samples taken at a sample interval.
Claim 33
Dependent Claim
13 words
The system of claim 30 , wherein the sample interval comprises 250 milliseconds.
Claim 34
Independent Claim
125 words
A system for handing off a call between networks, comprising: means for monitoring a quality of a first link between a mobile station and a wireless local area network (WLAN) when the mobile station is actively connected with the WLAN on a call; means for monitoring a quality of a second link between the mobile station and a cellular network when the mobile station is actively connected with the WLAN on the call; and means for triggering a handoff of the call from the WLAN to the cellular network when the quality of the first link is less than a handoff trigger threshold for a drop count duration and when the quality of the second link is greater than a minimum cellular link quality threshold.
Claim 35
Independent Claim
125 words
A system for handing off a call between networks, comprising: means for monitoring a quality of a first link between a mobile station and a wireless local area network (WLAN) when the mobile station is actively connected with the WLAN on a call; means for monitoring a quality of a second link between the mobile station and a cellular network when the mobile station is actively connected with the WLAN on the call; and means for triggering a handoff of the call from the WLAN to the cellular network when the quality of the first link is less than a handoff trigger threshold for a drop count duration and when the quality of the second link is greater than a minimum cellular link quality threshold.
Claim 36
Dependent Claim
77 words
The system of claim 32 , further comprising: means for monitoring the quality of the first link between the mobile station and the WLAN when the mobile station is actively connected with the cellular network on the call; and means for triggering a handoff of the call from the cellular network to the WLAN when the quality of the first link is greater than the handoff trigger threshold plus a hysteresis margin for a pick-up count duration.
Claim 37
Dependent Claim
14 words
The system of claim 32 , wherein the WLAN communicates using IEEE 802.11 protocol.
Claim 38
Dependent Claim
30 words
The system of claim 32 , wherein means for monitoring a quality of a first link between a mobile station and a WLAN comprises means for monitoring a WLAN metric.
Claim 39
Dependent Claim
44 words
The system of claim 35 , wherein the WLAN metric comprises one of a group of metrics consisting of a received signal strength, a signal to noise ration, a signal quality, an error vector magnitude, a bit error rate and a packet error rate.
Claim 40
Dependent Claim
31 words
The system of claim 32 , wherein means for monitoring a quality of a second link between the mobile station and a cellular network comprises means for monitoring a cellular metric.
Claim 41
Dependent Claim
32 words
The system of claim 37 , wherein the cellular metric comprises one of a group of metrics consisting of a received signal strength, a bit error rate and a frame error rate.
Claim 42
Independent Claim
121 words
A method for handing off a call between networks, comprising: monitoring a quality of a first link between a mobile station and a cellular network when the mobile station is actively connected with the cellular network on a call; monitoring a quality of a second link between the mobile station and a wireless local area network (WLAN) when the mobile station is actively connected with the cellular network on the call; and triggering a handoff of the call from the cellular network to the WLAN when the quality of the first link is less than a handoff trigger threshold for a drop count duration and when the quality of the second link is greater than a minimum WLAN link quality threshold.
Claim 43
Independent Claim
121 words
A method for handing off a call between networks, comprising: monitoring a quality of a first link between a mobile station and a cellular network when the mobile station is actively connected with the cellular network on a call; monitoring a quality of a second link between the mobile station and a wireless local area network (WLAN) when the mobile station is actively connected with the cellular network on the call; and triggering a handoff of the call from the cellular network to the WLAN when the quality of the first link is less than a handoff trigger threshold for a drop count duration and when the quality of the second link is greater than a minimum WLAN link quality threshold.
Claim 44
Dependent Claim
73 words
The method of claim 39 , further comprising: monitoring the quality of the first link between the mobile station and the cellular network when the mobile station is actively connected with the WLAN on the call; and triggering a handoff of the call from the WLAN to the cellular network when the quality of the first link is greater than the handoff trigger threshold plus a hysteresis margin for a pick-up count duration.
Claim 45
Dependent Claim
19 words
The method of claim 40 , further comprising tuning a control to change a value of the hysteresis margin.
Claim 46
Dependent Claim
20 words
The method of claim 40 , further comprising tuning a control to change a value of the drop count duration.
Claim 47
Dependent Claim
14 words
The method of claim 39 , wherein the WLAN communicates using IEEE 802.11 protocol.
Claim 48
Dependent Claim
27 words
The method of claim 39 , wherein monitoring a quality of a first link between a mobile station and a cellular network comprises monitoring a cellular metric.
Claim 49
Dependent Claim
26 words
The method of claim 39 , wherein monitoring a quality of a second link between the mobile station and a WLAN comprises monitoring a WLAN metric.
References Cited (Backward Citations)
US5081679A
Cited
US5548808A
Cited
US5913168A
Cited
US6088591A
Cited
US6134439A
Cited
US6629151B1
Cited
US20020085516A1
Cited
US20030133421A1
Cited
US20040233840A1
Cited
US20050059400A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2009-07-24 | 2010-01-23 | 2010-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2013-07-24 | 2014-01-23 | 2014-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2017-07-24 | 2018-01-23 | 2018-07-25 | $7700.00 | Window Closed / Lapsed |