US6097958A
Expired / Lapsed
US
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Method and apparatus for locating and tracking cellular telephones in a CDMA cellular communication network
Assignee: Nortel Networks Ltd
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Filing: 1997-10-10
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Granted: 2000-08-01
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Expires: 2017-10-10
Abstract
Abstract A system and method for initially locating and subsequently tracking the location of one or more mobile phones in a cellular communication network are disclosed. Software for implementing a scheduling and tracking system ("STS") is incorporated into the base station controller ("BSC") of a cellular communication network for performing scheduling and tracking functions with respect to mobile phone location. In one aspect of the invention, time difference of arrival ("TDOA") techniques are used to determine a location of each of a number of designated mobile phones active in the network. In another aspect of the invention, a scheduling portion of the STS originates and maintains a schedule of time measurement updates with reference to the previous location of the mobile phone. In yet another aspect of the invention, a tracking portion of the STS keeps track of the location of each of the designated mobile phones over time.
Inventors
- 👤 Scott Bergen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:52
CPC Classifications
H; H04; H04W; H04W64/00; H04W4/00; H04W4/02
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
109 words
A method of tracking a plurality of cellular telephones in a cellular telephone network, the method comprising: selecting a plurality of cellular telephones to be tracked; scheduling time measurements for each of said selected cellular telephones, wherein said scheduling comprises assigning update times to said selected cellular telephones to achieve maximum possible separation between said update times across said cellular telephone network both temporally and geographically; for each of said selected cellular telephones: performing said time measurements according to said assigned update time; determining a location of said selected cellular telephone using said time measurements; and adding said determined location to a tracking log for said selected cellular telephone.
Claim 2
Independent Claim
109 words
A method of tracking a plurality of cellular telephones in a cellular telephone network, the method comprising: selecting a plurality of cellular telephones to be tracked; scheduling time measurements for each of said selected cellular telephones, wherein said scheduling comprises assigning update times to said selected cellular telephones to achieve maximum possible separation between said update times across said cellular telephone network both temporally and geographically; for each of said selected cellular telephones: performing said time measurements according to said assigned update time; determining a location of said selected cellular telephone using said time measurements; and adding said determined location to a tracking log for said selected cellular telephone.
Claim 3
Dependent Claim
38 words
The method of claim 1 wherein said assigning update times to said selected cellular telephones is based on a last update time, a cluster, and a current primary BTS active sector of each of said selected cellular telephones.
Claim 4
Dependent Claim
25 words
The method of claim 1 further comprising outputting information contained in one or more of said tracking logs in a manner designated by a user.
Claim 5
Dependent Claim
29 words
The method of claim 1 wherein said selecting comprises designating a class of service, wherein all cellular telephones of said designated class of service are selected to be tracked.
Claim 6
Dependent Claim
33 words
The method of claim 1 wherein said selecting comprises designating a geographic area of said cellular telephone network, wherein all cellular telephones active within said designated geographic area are selected to be tracked.
Claim 7
Dependent Claim
19 words
The method of claim 1 wherein said selecting comprises selecting all cellular telephones active within said cellular telephone network.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein said cellular telephone network is a CDMA network.
Claim 9
Dependent Claim
201 words
In a cellular communication network comprising a base station controller ("BSC") and a plurality of base station transceiver subsystems ("BTSes"), a method of locating and tracking a location of a plurality of cellular telephones comprising: identifying at least one cellular telephone to be located and tracked; for each of said identified cellular telephones, determining a primary BTS ("PBTS") and at least two secondary BTSes ("SBTSes") for said identified cellular telephone; scheduling a time for performing time measurements for each of said identified cellular telephones, wherein said scheduling comprises assigning update times to said selected cellular telephones to achieve maximum possible separation between said update times across said cellular telephone network both temporally and geographically; for each of said identified cellular telephones: immediately prior to said scheduled time, sending setup information to each of said PBTS and SBTSes; subsequent to said sending setup information, said PBTS ramping up the power of said identified cellular telephone; at said scheduled time, said PBTS and said SBTS performing said time measurements and forwarding said time measurements to said BSC; and said BSC determining a location of said cellular telephone using said time measurements and adding said location to a tracking log for said cellular telephone.
Claim 10
Dependent Claim
201 words
In a cellular communication network comprising a base station controller ("BSC") and a plurality of base station transceiver subsystems ("BTSes"), a method of locating and tracking a location of a plurality of cellular telephones comprising: identifying at least one cellular telephone to be located and tracked; for each of said identified cellular telephones, determining a primary BTS ("PBTS") and at least two secondary BTSes ("SBTSes") for said identified cellular telephone; scheduling a time for performing time measurements for each of said identified cellular telephones, wherein said scheduling comprises assigning update times to said selected cellular telephones to achieve maximum possible separation between said update times across said cellular telephone network both temporally and geographically; for each of said identified cellular telephones: immediately prior to said scheduled time, sending setup information to each of said PBTS and SBTSes; subsequent to said sending setup information, said PBTS ramping up the power of said identified cellular telephone; at said scheduled time, said PBTS and said SBTS performing said time measurements and forwarding said time measurements to said BSC; and said BSC determining a location of said cellular telephone using said time measurements and adding said location to a tracking log for said cellular telephone.
Claim 11
Dependent Claim
38 words
The method of claim 8 wherein said assigning update times to said selected cellular telephones is based on a last update time, a cluster, and a current primary BTS active sector of each of said selected cellular telephones.
Claim 12
Dependent Claim
25 words
The method of claim 8 further comprising outputting information contained in one or more of said tracking logs in a manner designated by a user.
Claim 13
Dependent Claim
29 words
The method of claim 8 wherein said selecting comprises designating a class of service, wherein all cellular telephones of said designated class of service are selected to be tracked.
Claim 14
Dependent Claim
33 words
The method of claim 8 wherein said selecting comprises designating a geographic area of said cellular telephone network, wherein all cellular telephones active within said designated geographic area are selected to be tracked.
Claim 15
Dependent Claim
19 words
The method of claim 8 wherein said selecting comprises selecting all cellular telephones active within said cellular telephone network.
Claim 16
Dependent Claim
14 words
The method of claim 8 wherein said cellular telephone network is a CDMA network.
Claim 17
Independent Claim
199 words
A method of updating a schedule of time measurements to be performed for a plurality of cellular telephones in a cellular telephone network, said time measurements for use in determining and tracking a location of said cellular telephones, the method comprising: sorting said current cellular telephones by cluster; assigning an update time slot to each of said current cellular telephones based on a last update time, a cluster, and a current primary BTS active sector of said current cellular telephone to achieve maximum possible separation between said update times across said cellular telephone network both temporally and geographically; adding additional cellular telephones to said schedule, each of said additional cellular telephones being added to said schedule based on a primary BTS active sector of said additional cellular telephone to achieve maximum possible separation between said update times across said cellular telephone network both temporally and geographically; identifying scheduling conflicts between at least two cellular telephones; and resolving scheduling conflicts by moving a higher priority one of said at least two cellular telephones up on said schedule, moving a lower priority one of said at least two cellular telephones down on said schedule, or both until said conflict is resolved.
Claim 18
Independent Claim
199 words
A method of updating a schedule of time measurements to be performed for a plurality of cellular telephones in a cellular telephone network, said time measurements for use in determining and tracking a location of said cellular telephones, the method comprising: sorting said current cellular telephones by cluster; assigning an update time slot to each of said current cellular telephones based on a last update time, a cluster, and a current primary BTS active sector of said current cellular telephone to achieve maximum possible separation between said update times across said cellular telephone network both temporally and geographically; adding additional cellular telephones to said schedule, each of said additional cellular telephones being added to said schedule based on a primary BTS active sector of said additional cellular telephone to achieve maximum possible separation between said update times across said cellular telephone network both temporally and geographically; identifying scheduling conflicts between at least two cellular telephones; and resolving scheduling conflicts by moving a higher priority one of said at least two cellular telephones up on said schedule, moving a lower priority one of said at least two cellular telephones down on said schedule, or both until said conflict is resolved.
Claim 19
Dependent Claim
27 words
The method of claim 15 further comprising preempting one or more lower priority ones of said at least two cellular telephones if said conflict cannot be resolved.
Claim 20
Dependent Claim
29 words
The method of claim 15 wherein said assigning is performed such that time measurements are not performed simultaneously for more than one current cellular telephone in a single cluster.
Claim 21
Dependent Claim
28 words
The method of claim 15 wherein said assigning is performed such that time measurements may be performed simultaneously for more than one current cellular telephone in different clusters.
Claim 22
Dependent Claim
14 words
The method of claim 15 wherein said cellular telephone network is a CDMA network.
Claim 23
Dependent Claim
14 words
The method of claim 15 wherein each said cluster comprises at least one sector.
Claim 24
Dependent Claim
27 words
The method of claim 15 wherein said network is a multiple carrier frequency network, the method further comprising designating separate clusters for said multiple carrier frequency network.
Claim 25
Dependent Claim
105 words
Apparatus for tracking a plurality of cellular telephones in a cellular telephone network, the apparatus comprising: means for scheduling time measurements for each of a plurality of selected cellular telephones, wherein said scheduling comprises assigning update times to said selected cellular telephones to achieve maximum possible separation between said update times across said cellular telephone network both temporally and geographically; means for, with respect to each of said selected cellular telephones, performing said time measurements according to said scheduling, determining a location of said selected cellular telephone using said time measurements, and adding said determined location to a tracking log for said selected cellular telephone.
Claim 26
Dependent Claim
105 words
Apparatus for tracking a plurality of cellular telephones in a cellular telephone network, the apparatus comprising: means for scheduling time measurements for each of a plurality of selected cellular telephones, wherein said scheduling comprises assigning update times to said selected cellular telephones to achieve maximum possible separation between said update times across said cellular telephone network both temporally and geographically; means for, with respect to each of said selected cellular telephones, performing said time measurements according to said scheduling, determining a location of said selected cellular telephone using said time measurements, and adding said determined location to a tracking log for said selected cellular telephone.
Claim 27
Dependent Claim
43 words
The apparatus of claim 22 wherein said means for scheduling comprises means for assigning update times to said selected cellular telephones based on a last update time, a cluster, and a current primary BTS active sector of each of said selected cellular telephones.
Claim 28
Dependent Claim
27 words
The apparatus of claim 22 further comprising means for outputting information contained in one or more of said tracking logs in a manner designated by a user.
Claim 29
Dependent Claim
29 words
The apparatus of claim 22 wherein said selecting comprises designating a class of service, wherein all cellular telephones of said designated class of service are selected to be tracked.
Claim 30
Dependent Claim
33 words
The apparatus of claim 22 wherein said selecting comprises designating a geographic area of said cellular telephone network, wherein all cellular telephones active within said designated geographic area are selected to be tracked.
Claim 31
Dependent Claim
19 words
The apparatus of claim 22 wherein said selecting comprises selecting all cellular telephones active within said cellular telephone network.
Claim 32
Dependent Claim
14 words
The apparatus of claim 22 wherein said cellular telephone network is a CDMA network.
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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) | 2003-08-01 | 2004-01-31 | 2004-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-08-01 | 2008-01-31 | 2008-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-08-01 | 2012-01-31 | 2012-08-01 | $7700.00 | Window Closed / Lapsed |