US5737689A
Expired / Lapsed
US
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Method for preventing calls of bad quality from being disconnected in a cellular mobile radio system
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1994-06-14
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Granted: 1998-04-07
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Expires: 2014-06-14
Abstract
Abstract In a cellular mobile radio system, a handoff method allows a mobile station to be handed off from one base station to another base station when an alarm case occurs in an operator controlled manner in an attempt to save the connection. A cell border is defined where a handoff is allowed from a first base station to a second base station by comparing the radio transmissions between a mobile station and the first and second base stations. The handoff border is then moved by an offset value to form an alarm case cell border, wherein an alarm case handoff from the first base station to the second base station is allowed only when the mobile station experiences an alarm case and is in the area bounded by the handoff cell border and the alarm case handoff border.
Inventors
- 👤 Per Viktor Israelsson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 00:32
CPC Classifications
H; H04; H04W; H04W36/00; H04W36/24; H04W36/30; H04W36/302
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
128 words
A method for handoff in an alarm case in a cellular mobile radio telephone system having a plurality of cells each providing radio coverage by a base station and having a plurality of mobile stations associated with said cells, said method comprising the steps of: defining a handoff cell border where the handoff is allowed from a first base station to a second base station by comparing radio transmissions between a mobile station and said first and second base stations; modifying said handoff border by the offset value to form an alarm case handoff border, wherein the alarm case handoff is allowed only when said mobile station experiences the alarm case and is in an area bounded by said handoff cell border and said alarm case handoff border.
Claim 2
Independent Claim
128 words
A method for handoff in an alarm case in a cellular mobile radio telephone system having a plurality of cells each providing radio coverage by a base station and having a plurality of mobile stations associated with said cells, said method comprising the steps of: defining a handoff cell border where the handoff is allowed from a first base station to a second base station by comparing radio transmissions between a mobile station and said first and second base stations; modifying said handoff border by the offset value to form an alarm case handoff border, wherein the alarm case handoff is allowed only when said mobile station experiences the alarm case and is in an area bounded by said handoff cell border and said alarm case handoff border.
Claim 3
Dependent Claim
40 words
A method for handoff in an alarm case according to claim 1, wherein said handoff cell border is located where signal strength of the first base station plus a hysteresis value equals the signal strength of said second base station.
Claim 4
Dependent Claim
23 words
A method for handoff in an alarm case according to claim 2, wherein said hysteresis value is set between three and four decibels.
Claim 5
Dependent Claim
50 words
A method for handoff in an alarm case according to claim 1, wherein said alarm case handoff border is located where signal strength of said first base station plus a hysteresis value minus an offset value equals the signal strength of said second base station plus a first predetermined value.
Claim 6
Dependent Claim
20 words
A method for handoff in an alarm case according to claim 4, wherein said offset value is a negative value.
Claim 7
Dependent Claim
23 words
A method for handoff in an alarm case according to claim 4, wherein said hysteresis value is set between 3 and 4 decibels.
Claim 8
Dependent Claim
39 words
A method for handoff in an alarm case according to claim 1, wherein said alarm case occurs when a bit error rate of a signal between the mobile station and the first base station exceeds a second predetermined level.
Claim 9
Independent Claim
117 words
A method for directed retry in a cellular mobile radio telephone system having a plurality of cells each providing radio coverage by a base station and having a plurality of mobile stations associated with said cells, said method comprising the steps of: defining a nominal cell border by comparing the radio transmissions between a mobile station and first and second base stations; modifying said nominal border by an offset value to form a directed retry border, wherein the directed retry is allowed only when said mobile station attempts to access said first base station and said first base station does not have an available traffic channel and the mobile station is located beyond said directed retry border.
Claim 10
Independent Claim
117 words
A method for directed retry in a cellular mobile radio telephone system having a plurality of cells each providing radio coverage by a base station and having a plurality of mobile stations associated with said cells, said method comprising the steps of: defining a nominal cell border by comparing the radio transmissions between a mobile station and first and second base stations; modifying said nominal border by an offset value to form a directed retry border, wherein the directed retry is allowed only when said mobile station attempts to access said first base station and said first base station does not have an available traffic channel and the mobile station is located beyond said directed retry border.
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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) | 2001-04-06 | 2001-10-06 | 2002-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-06 | 2005-10-06 | 2006-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-06 | 2009-10-06 | 2010-04-07 | $7700.00 | Window Closed / Lapsed |