US5555445A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of intra-cell and inter-cell handover in a mobile communications system
Assignee: Nortel Networks Ltd
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Filing: 1994-07-15
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Granted: 1996-09-10
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Expires: 2014-07-15
Abstract
Abstract A method of performing handover of a call associated with a mobile station in one cell but moving towards another cell includes making a first attempt, using for example a MUX1 SNIFF procedure, on the channel allocated to the mobile station for that call. If that attempt fails, the mobile station is allocated a different channel in the one cell and makes a second attempt. This different channel allocation (intracell handover) is performed even if there are no better signal characteristics achieved as a result. This procedure makes it more likely to be possible to achieve handover when a second mobile station associated with an adjacent cell and operating on the same channel as the first mobile station is also within range of the base station of the other cell.
Inventors
- 👤 Andrew J. Booth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:22
CPC Classifications
H; H04; H04W; H04W36/00; H04W36/24; H04W36/30; H04W36/302; H04W36/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
175 words
A method for use in a cellular mobile communications system for performing handover, from a first base station to a second base station, of a call associated with a mobile station moving between adjacent cells corresponding to said base stations, said mobile station being in communication with the first base station via a first communications channel associated with that base station, the method comprising the steps of; monitoring from the first base station the signal level of the mobile station so as to determine when that signal level falls below a predetermined value; responsive to said determination attempting to detect the mobile station from said second base station; effecting intercell handover of the mobile station to the second base station when said detection attempt is successful; when said detection attempt is unsuccessful; effecting intrahandover of the mobile station from said first channel to a further channel of the first base station and repeating said monitoring and detection attempting steps; and effecting intercell handover to said second base station if said repeated detection attempt is successful.
Claim 2
Independent Claim
175 words
A method for use in a cellular mobile communications system for performing handover, from a first base station to a second base station, of a call associated with a mobile station moving between adjacent cells corresponding to said base stations, said mobile station being in communication with the first base station via a first communications channel associated with that base station, the method comprising the steps of; monitoring from the first base station the signal level of the mobile station so as to determine when that signal level falls below a predetermined value; responsive to said determination attempting to detect the mobile station from said second base station; effecting intercell handover of the mobile station to the second base station when said detection attempt is successful; when said detection attempt is unsuccessful; effecting intrahandover of the mobile station from said first channel to a further channel of the first base station and repeating said monitoring and detection attempting steps; and effecting intercell handover to said second base station if said repeated detection attempt is successful.
Claim 3
Dependent Claim
40 words
A method as claimed in claim 1, wherein for intercell handover the first base station instructs all surrounding base stations to try to detect the mobile station and handover is performed to a base station which detects the mobile station.
Claim 4
Dependent Claim
87 words
A method as claimed in claim 2, wherein the surrounding base stations are instructed to perform a MUX1 SNIFF comprising tuning to the first channel allocated to the mobile station for the call, trying to decode the identity of the mobile station, and in the event of decoding the identity measuring the received signal strength and reporting the measured signal strength to the first base station, the first base station handing over the call to the base station which responds first with an adequate received signal strength.
Claim 5
Dependent Claim
22 words
A method as claimed in claim 1, and including the step of dropping the call if the second detection attempt has failed.
Claim 6
Dependent Claim
36 words
A method as claimed claim 1 and including the step of making a further intracell handover of the mobile station to a third channel of the first base station if the second detection attempt has failed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-09-10 | 2000-03-11 | 2000-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-09-10 | 2004-03-11 | 2004-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-09-10 | 2008-03-11 | 2008-09-10 | $7700.00 | Window Closed / Lapsed |