US6169900B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reverse inter-MSC handover
Assignee: Nokia Oyj
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Filing: 1996-12-17
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Granted: 2001-01-02
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Expires: 2016-12-17
Abstract
Abstract The GSM system includes a protocol for reestablishing a lost call. A problem occurs if the call is lost after an inter-MSC (MSC-A, MSC-B) handover, resulting in that the system does not know into which MSC the subscriber data of a mobile station (MS) has been updated. If the MSC has changed during the call, and the MS is no longer able to contact the cell served by the original MSC-A, the call will be lost. In the method according to the invention, the MSC serving the location area of the mobile station detects a start message ( 1 ′) transmitted by the mobile station and containing the Last Location Area Identifier of the mobile station. Based on the Last Location Area Identifier, the second center MSC-B, which detects the start message ( 1 ′), determines the first center MSC-A in whose area the call was started. Following this, the second center MSC-B may establish a connection to the first center MSC-A. At this stage, the centers (MSC-A) and MSC-B) reverse roles and the method proceeds as in a conventional inter-MSC handover. The method of the invention for establishing a connection may also be applied to a satellite system that uses the GSM system network structure.
Inventors
- 👤 Lauri Lahtinen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:57
CPC Classifications
H; H04; H04W; H04W36/00; H04W36/12; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/185; H04B7/1853; H04B7/18539; H04B7/18541; H04W36/0005; H04W36/0055; H04W36/0079
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
180 words
A method for establishing or re-establishing a call between a mobile station (MS) and a mobile communication system comprising at least a first mobile switching centre (MSC-A) and a second mobile switching centre (MSC-B), wherein: subscriber information relating to the mobile station (MS) is stored in the first mobile switching centre (MSC-A); a call can be routed via an anchor centre holding information relating to the call; a call can be handed over from the anchor centre to another centre; and the mobile station (MS) transmits a start message ( 1 ′); the method being characterized by the steps of: receiving the start message ( 1 ′) at the second MSC; detecting, on the basis of the start message, that the subscriber information relating to the mobile station (MS) is stored in the first MSC; initiating handover from the second MSC to the first MSC, and using, initially, the second MSC as the anchor MSC; and reversing the functions of the first MSC and the second MSC so that after the reverse the first MSC functions as the anchor centre.
Claim 2
Independent Claim
180 words
A method for establishing or re-establishing a call between a mobile station (MS) and a mobile communication system comprising at least a first mobile switching centre (MSC-A) and a second mobile switching centre (MSC-B), wherein: subscriber information relating to the mobile station (MS) is stored in the first mobile switching centre (MSC-A); a call can be routed via an anchor centre holding information relating to the call; a call can be handed over from the anchor centre to another centre; and the mobile station (MS) transmits a start message ( 1 ′); the method being characterized by the steps of: receiving the start message ( 1 ′) at the second MSC; detecting, on the basis of the start message, that the subscriber information relating to the mobile station (MS) is stored in the first MSC; initiating handover from the second MSC to the first MSC, and using, initially, the second MSC as the anchor MSC; and reversing the functions of the first MSC and the second MSC so that after the reverse the first MSC functions as the anchor centre.
Claim 3
Dependent Claim
30 words
A method as claimed in claim 1 , characterized in that the start message ( 1 ′) comprises an identifier (Last-LAI) identifying the last location area of the mobile station.
Claim 4
Dependent Claim
96 words
A method as claimed in claim 2 , characterized in that: the method is used for re-establishing a call which has been initited in the area of the first MSC (MSC-A) and which has been lost in the area of the second centre (MSC-B); the start message ( 1 ′) is a Reestablishment-Request requesting reestablishment of the lost call; and the subscriber information relating to the mobile station (MS) is detected to be stored in the first MSC (MSC-A), on the basis of the identifier Last-LAI) identifying the last location area of the mobile station (MS).
Claim 5
Dependent Claim
69 words
A method as claimed in claim 1 , characterized in that: the method is used for establishing a mobile terminating call in a satellite communication system; the start message ( 1 ′) transmitted by the mobile station is preceded by paging of the mobile station (MS), initiated by the first centre (MSC-A); and the mobile station (MS) responds to the paging by sending said start message ( 1 ′).
Claim 6
Dependent Claim
29 words
A method as claimed in claim 1 , characterized in that the method is used for establishing a call originated by mobile station (MS) in a satellite communication system.
Claim 7
Dependent Claim
69 words
A method as claimed in claim 2 , characterized in that: the method is used for establishing a mobile terminating call in a satellite communication system; the start message ( 1 ′) transmitted by the mobile station is preceded by paging of the mobile station (MS), initiated by the first centre (MSC-A); and the mobile station (MS) responds to the paging by sending said start message ( 1 ′).
Claim 8
Dependent Claim
29 words
A method as claimed in claim 2 , characterized in that the method is used for establishing a call originated by mobile station (MS) in a satellite communication system.
References Cited (Backward Citations)
WO1994028689A1
Cited
US5487065A
Cited
US5930712A
Cited
US5649290A
Cited
US5884173A
Cited
US5737703A
Cited
US5659596A
Cited
US5896373A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-01-02 | 2004-07-03 | 2005-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-01-02 | 2008-07-03 | 2009-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-01-02 | 2012-07-03 | 2013-01-02 | $7700.00 | Window Closed / Lapsed |