US7738873B2
Active / In Force
US
⏱️ 1.1 years remaining
Method and system for triggering handoff of a call between networks
Assignee: Cisco Technology Inc
•
Filing: 2007-11-26
•
Granted: 2010-06-15
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Expires: 2027-11-26
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
2026-10-25 10:05
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: 26
Claim 1
Independent Claim
157 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 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; and preventing a handoff of the call from the cellular network to the WLAN until expiration of a first amount of time as long as the quality of the second link remains above the minimum cellular link quality threshold.
Claim 2
Independent Claim
157 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 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; and preventing a handoff of the call from the cellular network to the WLAN until expiration of a first amount of time as long as the quality of the second link remains above the minimum cellular link quality threshold.
Claim 3
Dependent Claim
20 words
The method of claim 1 , further comprising tuning a control to change a value of the drop count duration.
Claim 4
Dependent Claim
21 words
The method of claim 1 , further comprising tuning a control to change a value of the first amount of time.
Claim 5
Independent Claim
165 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; 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; and prevent a handoff of the call from the cellular network to the WLAN until expiration of a first amount of time as long as the quality of the second link remains above the minimum cellular link quality threshold.
Claim 6
Independent Claim
165 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; 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; and prevent a handoff of the call from the cellular network to the WLAN until expiration of a first amount of time as long as the quality of the second link remains above the minimum cellular link quality threshold.
Claim 7
Dependent Claim
78 words
The system of claim 4 , 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 8
Dependent Claim
25 words
The system of claim 5 , wherein the mobile station further comprises a tuning knob operable to tune the hysteresis margin to change its value.
Claim 9
Dependent Claim
26 words
The system of claim 4 , wherein the mobile station further comprises a tuning knob operable to tune the drop count duration to change its value.
Claim 10
Dependent Claim
27 words
The system of claim 4 , wherein the mobile station further comprises a tuning knob operable to tune the first amount of time to change its value.
Claim 11
Independent Claim
165 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; 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; and means for preventing a handoff of the call from the cellular network to the WLAN until expiration of a first amount of time as long as the quality of the second link remains above the minimum cellular link quality threshold.
Claim 12
Independent Claim
165 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; 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; and means for preventing a handoff of the call from the cellular network to the WLAN until expiration of a first amount of time as long as the quality of the second link remains above the minimum cellular link quality threshold.
Claim 13
Dependent Claim
127 words
Software embedded in a computer readable medium comprising code that, when executed by a processor, is operable to: monitor 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; 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 14
Dependent Claim
127 words
Software embedded in a computer readable medium comprising code that, when executed by a processor, is operable to: monitor 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; 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 15
Dependent Claim
51 words
The medium of claim 10 , wherein the code is further operable to prevent a handoff of the call from the cellular network to the WLAN until expiration of a first amount of time as long as the quality of the second link remains above the minimum cellular link quality threshold.
Claim 16
Dependent Claim
78 words
The medium of claim 11 , wherein the code 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 17
Dependent Claim
32 words
The medium of claim 10 , wherein code operable to monitor a quality of a first link between a mobile station and a WLAN comprises code operable to monitor a WLAN metric.
Claim 18
Dependent Claim
44 words
The medium of claim 13 , 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 19
Dependent Claim
33 words
The medium of claim 10 , wherein code operable to monitor a quality of a second link between the mobile station and a cellular network comprises code operable to monitor a cellular metric.
Claim 20
Dependent Claim
32 words
The medium of claim 15 , 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 21
Independent Claim
159 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; 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; and preventing a handoff of the call from the WLAN to the cellular network until expiration of a first amount of time as long as the quality of the second link remains above the minimum WLAN link quality threshold.
Claim 22
Independent Claim
159 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; 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; and preventing a handoff of the call from the WLAN to the cellular network until expiration of a first amount of time as long as the quality of the second link remains above the minimum WLAN link quality threshold.
Claim 23
Dependent Claim
20 words
The method of claim 17 , further comprising tuning a control to change a value of the drop count duration.
Claim 24
Dependent Claim
21 words
The method of claim 17 , further comprising tuning a control to change a value of the first amount of time.
Claim 25
Dependent Claim
27 words
The method of claim 17 , wherein monitoring a quality of a first link between a mobile station and a cellular network comprises monitoring a cellular metric.
Claim 26
Dependent Claim
26 words
The method of claim 17 , wherein monitoring a quality of a second link between the mobile station and a WLAN comprises monitoring a WLAN metric.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2013-06-14 | 2013-12-14 | 2014-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2017-06-14 | 2017-12-14 | 2018-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2021-06-14 | 2021-12-14 | 2022-06-15 | $7700.00 | Window Closed / Lapsed |