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`
`I 1111111111111111 11111 11111111111111111111111111111111111 111111111111111111
`
`US005485163A
`
`
`United States Patent
`[19]
`
`Singer et al.
`
`5,485,163
`Patent Number:
`[11]
`Jan. 16, 1996
`Date of Patent:
`[45]
`
`[54]PERSONAL LOCATOR SYSTEM
`
`5/1993 Song ....................................... 364/449
`
`
`
`
`
`
`
`Ill.[73]Assignee: Motorola, Inc., Schaumburg,
`
`5,208,756
`
`
`
`6/1993 5,218,367 Sheffer et al ..
`
`
`
`6/1993 Comroe et al ..
`5,218,716
`[75]Inventors: Martin H. Singer, Northbrook; Daniel
`
`
`
`
`5,247,698
`
`9/1993 Sawyer et al ..
`
`
`Tell, Deerfield; Anthony Kobrinetz,
`
`9/1993 Wohl et al ..
`5,247,700
`
`Hoffman Estates, all of Ill.
`
`
`5/1994 Kennedy et al ..
`5,317,323
`
`
`5,398,190
`5,404,376
`
`4/1995 Dent .
`
`5,418,537
`
`
`
`3/1995 Wortham ................................. 364/460
`
`5/1995 Bird ........................................ 342/357
`
`[21]Appl. No.: 220,342
`
`[22]Filed:Mar. 30, 1994
`3-239091 10/1991 Japan .
`
`
`6 ........................................................ GOlS 3/02
`
`
`[51]Int. Cl.
`
`Primary Examiner-Theodore M. Blum
`[52] U.S. Cl ..............................................
`
`
`
`342/419 Attorney, 342/457; Agent, or Firm-Jeffrey G. Toler; Kevin A. Buford
`
`
`[58]Field of Search .....................................
`342/457, 419;
`ABSTRACT
`379/59 [57]
`A system and method for locating a portable locator device
`
`
`
`
`
`
`
`in a communications network. The portable locator unit
`
`
`
`
`(PLU) (4) is activated either by an external signal (62)
`
`
`
`
`
`generated in response to remote activation source, such as a
`
`
`subscriber (6, 8) or PLU detector (106, 108), or by an
`
`
`
`
`
`internal activation signal triggered e.g. by the wearer. Once
`
`
`
`activated, the PLU (4) transmits a location signal (66). This
`
`
`location signal (66) is received by one or more network
`
`service nodes (20, 22, 24) which forward the information
`
`
`
`along with identifying service node information to a network
`
`
`
`
`location processor (26, 28). After having determined the
`
`
`
`location of the PLU (4) from the received information, the
`
`
`
`network location processor (26, 28) forwards this informa­
`
`
`
`tion to a designated source, such as the requesting subscriber
`
`or other authorized user (6, 8).
`
`[56]
`
`
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`1/1974
`3,787,862
`Jacobson.
`3,806,937
`4/1974
`Lindley.
`King.
`3,872,477
`3/1975
`3,984,807
`Haemmig.
`10/1976
`4,215,345
`7/1980
`MacDoran.
`4,229,620
`10/1980
`Schaible.
`4,728,959
`3/1988
`
`Maloney et al ..
`12/1989
`4,888,593
`Friedman et al ..
`4,899,135
`2/1990
`Ghahariiran
`5,017,926
`5/1991
`Ames et al ..
`5,021,794
`6/1991
`Lawrence.
`5,099,248
`Brommer.
`3/1992
`5,128,925
`7/1992
`
`Domstetter et al ..
`5,146,231
`9/1992
`Ghaem et al ..
`12/1992
`5,173,709
`Lauro et al ..
`
`FOREIGN PATENT DOCUMENTS
`
`
`
`
`
`38 Claims, 4 Drawing Sheets
`
`.-----;BTS \ 18
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`I
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`
`I
`
`/
`/
`
`�_/
`_.i.----
`
`I
`I
`
`6
`
`I
`I
`
`12
`
`8
`
`36
`
`Cisco v. TracBeam / CSCO-1009
`Page 1 of 12
`
`

`

`5,485,163
`U.S. Patent
`Jan. 16, 1996 Sheet 1 of 4
`
`F IG.1
`24
`
`22
`
`r-------1
`
`18
`
`//
`/
`/
`/
`I
`1
`
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`20
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`BTS \
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`4 '"'
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`I/ //
`\ 16
`/
`\_ /
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`�
`_........_ ,,/ �
`l
`BTS 1 ;
`
`30
`BSC
`
`\
`
`\
`\
`
`'
`'
`.......
`
`'
`
`26
`
`MSC
`VLR
`
`28
`
`I
`
`6
`
`I
`
`I
`/
`/
`/
`/
`_,,,
`
`8
`
`36
`
`Cisco v. TracBeam / CSCO-1009
`Page 2 of 12
`
`

`

`5,485,163
`U.S. Patent Jan. 16, 1996 Sheet 2 of 4
`
`F IG.2
`
`5 2
`SUBSCRIBER ACCESSES THE NETWORK
`
`
`../
`PLU NUMBER
`ENTERS
`!
`J 4
`SUBSCRIBER ENTERS PIN;
`
`
`
`
`PL SYSTEM CONFIRMS AUTHORIZATION
`
`•
`J 6
`
`
`
`SUBSCRIBER ENTERS DESIRED FEATURE
`
`
`(E.G., PLU ACTIVATION} AND LOCATION
`
`• . .
`0
`
`PL SYSTEM GENERATES PLU ACTIVATION
`./
`
`
`SIGNAL; TRANSMITS TO DETERMINED
`NODES FOR BROADCAST
`NETWORK
`!
`_j 2
`NETWORK NODE(S) BROADCAST PLU
`
`
`
`
`ACTIVATION SIGNAL
`•
`
`
`PLU RECEIVES ACTIVATION SIGNAL,
`6 4
`
`
`MONITORS NODE CONTROL/PAGING CHANNELS
`../
`
`
`FOR REGISTRATION INFORMATION, NODE
`
`
`WITH HIGEST SIGNAL QUALITY
`
`•
`
`PLU TRANSMITS A REGISTRATION/
`6 6
`
`
`
`LOCATION SIGNAL (INCLUDING PLU MIN)
`TO NODE
`!
`
`6 8
`
`
`
`NODE RECEIVES LOCATION SIGNAL, FORWARDS
`V
`
`PLU MIN AND NODE ID NUMBER (NIM)
`
`
`TO NODE'S CONTROLLER AND VLR
`
`•
`70
`
`
`NODE CONTROLLER AND VLR DETERMINE PLU
`I.,/
`
`
`LOCATION, FORWARDS SAME TO HLR
`!
`HLR FORMATS, FORWARDS LOCATION
`
`
`2
`./
`
`
`INFORMATION TO SUBSCRIBER OR OTHER
`
`DESIGNATED RECIPIENT
`
`Cisco v. TracBeam / CSCO-1009
`Page 3 of 12
`
`

`

`w
`
`.-1'-
`
`�
`l,C
`
`....
`
`
`��
`
`LOCATION
`
`Pl.U TRANSMITS
`
`91
`
`F IG.3
`
`YES
`
`ms, IITERMitES
`3 STR(H;[ST
`FOR SIGNALS FR(lt 3 OR Jim
`Pl.U RE-Tll£S TO TCH ASSIGtlD 85 Pl.U t.OfITOOS PAGING CHAtfELS
`
`BY tm:
`
`s
`
`ms, DETERMitES 3 STR(H;[ST
`79
`Pl.U �IT� PAGING CHAtfflS
`
`FOR RSS FROM 3 OR m:
`
`y s
`
`ItfOOMATION
`
`--,76
`
`EXIDm) PROTOC(l FOR AOOITl(IW. LOCATION
`tm: TRANSUITS RE-REGISTRATION
`
`C(MM) INCLOOING
`
`.--------------
`
`LOCATION ItfOOMATION REOl(STID, FORWARDED TO NODE 75
`
`EXTEM)[D
`
`SIGNAL ON TCH AT PREIITERlUtlD PLU RECEIVES PAGING SIGNALS,
`
`92
`
`OCTERIIIIED
`
`EACH m
`
`TIil OCLAY TO
`INTERVALS TRANSMITS RESPm AFTER PRE-
`
`SIGNAL
`ItfOOMATION ALONG 80
`
`LOCATION
`WITH REGISTRATION/LOCATION
`IDENTIFYING
`Pl.U TRANSMITS RSS Atll tm
`
`SIGNAL RECEIVED, 87
`
`�
`
`DETERMINATION -...
`
`LOCATIONS Atll TIMING ItfORMATION
`NOOE
`0-.
`ASSOCIATED
`
`LOCATION
`0-.
`WITH MIN TO HLR FOR PLU 00
`NOOE LOCATION FORWARD
`VLRS PROCESS NIN FOR
`
`96
`
`93
`
`FORWARDS TO HLR
`MAHON, DETERMit£S Pl.U LOCATION,
`TIMING Atll tm:
`NODE CONTR(lLER/VLR
`PROC£SSES "'""
`
`0
`
`,i::..
`95
`
`LOCATION ltfOR-
`
`SIGNAL WITH TIMING ItfOOMATION
`RECEIVING ms FORWARD LOCATION
`
`TO ASSOCIATED
`
`VLR
`
`SIGNAL CHARACTERISTIC
`
`SIGNAL Atll RSS/NIN Itf OOMA HON
`RECEIVING tm F(EWAROS LOCATION
`
`1
`
`TO VLR/NOII CONJR(lLER
`
`PLU RELATIVE POSITION
`
`TO StmCRIBER
`
`TRANSMITTED
`
`POSITION OF SWSCRIBE
`DETERMitED
`
`RELATIVE
`SOOSCRIBER LOCATION
`
`TO Pl.U OETERMIIED
`R
`
`RSS Itf OOMA TION, OETERIIItES
`PLU
`82
`NOOE CONTR(lLER/VLR
`
`LOCATION FORWARDS TO HLR
`
`PROCESSES
`
`LOCATION
`PLU LOCATION OCTERMINED FR�
`
`Cisco v. TracBeam / CSCO-1009
`Page 4 of 12
`
`

`

`U.S. Patent Jan. 16, 1996 Sheet 4 of 4 5,485,163
`
`F IG.4
`
`,.,,-105
`104
`
`---
`------------
`--
`
`108
`
`112
`
`NODE
`
`000
`
`000
`000
`000
`
`110
`
`a--+------1
`
`NETWORK
`
`114
`
`HLR
`
`BUILDING
`NODE
`
`120
`
`Cisco v. TracBeam / CSCO-1009
`Page 5 of 12
`
`

`

`1
`
`5,485,163
`
`2
`
`PERSONAL LOCATOR SYSTEM
`
`FIELD OF THE INVENTION
`
`or PLU detector, or by an internal activation signal triggered
`
`
`
`
`
`
`
`e.g. by the wearer. Once activated, the PLU transmits a
`
`
`
`
`
`location signal. This location signal is received by one or
`
`
`more network service nodes which forward the information
`
`
`
`
`
`This invention relates to a system for locating persons or 5
`
`
`
`along with identifying service node information to a network
`
`
`
`
`objects, and in particular a wireless communication system
`
`
`
`
`
`location processor. After having determined the location of
`
`
`
`
`for use in locating and tracking persons and/or objects.
`
`
`
`the PLU from the received information, the network location
`
`
`
`
`processor forwards this information to a designated source,
`
`
`
`such as the requesting subscriber or other authorized user.
`10
`
`
`
`Today's news numbs us with accounts of kidnapping and
`
`
`
`
`theft. Even the most hardened cynics are haunted by the
`FlG. 1 illustrates a communications network in accor­
`
`
`
`
`
`
`
`stories of child abductions: a stranger dragging a child from
`
`
`
`
`
`
`her home, adolescents taking a screaming toddler from a dance with the present invention.
`
`
`
`
`shopping mall, infants kidnapped from a hospital. Constant
`a PLUFlG. 2 illustrates a flowchart of steps for locating
`
`
`
`15
`
`vigilance, and fear, have become all to common place for
`
`
`using a first embodiment of the present invention.
`
`parent and child alike.
`
`
`FlG. 3 is a flowchart of further steps that may be used in
`
`
`Those solutions that have been offered in the past are of
`
`
`
`determining and communicating the location of the PLU in
`
`
`limited effectiveness, or as a practical matter unavailable to
`
`
`
`
`
`accordance with another embodiment of the present inven-
`
`the average person. Child monitoring devices, such as
`
`
`20 tion.
`
`described in U.S. Pat. No. 4,899,135, have a limited range,
`
`
`FlG. 4 is a flowchart of yet another embodiment for
`
`
`
`
`
`and once a child is beyond that range provides no means for
`
`
`
`activating a PLU in accordance with the present invention.
`
`
`
`
`
`relocating the child. Emergency locator systems, such as
`
`shown in U.S. Pat. No. 5,021,794, provide a means for
`DESCRIPTION OF A PREFERRED
`
`
`
`
`homing in on a child from a greater range, but also require
`25
`EMBODIMENT
`
`
`
`the additional assistance of mobile homing units and remain
`The present invention provides a unique solution to the
`
`
`
`
`
`
`
`
`
`ineffective beyond a still limited broadcasting range of the
`
`
`problems discussed above by using a low power and inex­
`homing beacon.
`
`
`
`
`pensive portable locator unit (PLU) in conjunction with a
`While there are technologies offering better location
`
`
`
`
`
`
`
`communications system having wireless service nodes to
`
`
`
`these remain mostly out of reach of the average 30
`methods,
`
`
`
`allow a subscriber to locate the PLU. FlG. 1 illustrates one
`
`
`
`person due to the cost prohibitive nature of the solution.
`
`
`such communications network. In this case the portable
`
`
`
`Thus, while RF tags installed on vehicles permit the location
`
`
`
`child, to a lost or abducted locator unit (PLU) 4 is attached
`
`
`
`of stolen automobiles, the transmitters for such tags require
`
`
`and has the form of a tag, an ornamental bracelet, or the like.
`
`
`
`high power sources (car batteries), are relatively expensive
`
`
`
`While the PLU has been illustrated taking this specific form,
`
`
`
`
`(currently over five hundred dollars), and require the inter-35
`
`
`
`with appropriate miniaturization it could be incorporated in
`
`
`
`
`vention of local police with additional hardware and soft­
`
`
`
`
`
`almost any object, such as a belt, watch, earring, etc. The
`
`
`ware (at more expense) for tracking the car. Emergency
`
`
`
`PLU includes a low power source, a transceiver, a memory
`
`
`systems, such as that described in U.S. Pat. No. 5,218,367,
`
`
`
`for storing instructions and other information (such as the
`
`
`
`
`
`represent similarly expensive solutions, relying upon an on
`
`
`
`PLU identification) necessary for the operation of the unit,
`
`
`
`board emergency activation circuitry and a high power 40
`
`
`
`and an antenna (not shown). It is preferred, in order to
`
`
`
`
`
`source for the continuous multicell control signal scan and
`
`
`conserve power, that the PLU be in receive only mode until
`
`
`
`
`the response transmissions thereto. Likewise, any system
`
`
`activated for location purposes.
`
`
`
`
`incorporating a GPS (Global Positioning System) receiver
`
`
`
`Following activation of PLU 4, the location of PLU 4 is
`
`
`
`
`
`will, although providing accurate location information, add
`
`
`determined using one or more service nodes of a commu­
`
`
`
`
`
`undesirable bulk and several hundred dollars expense to the 45
`
`
`nications network. These nodes are illustrated in FlG. 1 as
`
`locator device.
`
`base transceiving stations (BTS) 20, 22, and 24 of a com­
`
`
`Any solution to this need for inexpensive locator devices
`
`
`munications network including a cellular telephony infra­
`
`should also be balanced against the right to privacy in our
`
`
`
`
`
`
`
`structure. The network is not limited to a cellular system,
`
`own personal affairs. Safeguards must exist against
`
`
`
`
`any cellular 50 and in some regions may not even include
`
`
`unwanted third party (listening) in on others' locations.
`
`
`
`service nodes. Thus, the service nodes may be part of such
`
`
`
`Thus, while any effective solution will provide an inexpen­
`
`
`
`
`differing systems as a trunked radio, satellite, or personal
`
`
`
`
`
`sive locating system, it should also include subsystems to
`
`
`
`
`communicator service (PCS) system, and it is expected that
`
`
`
`ensure that only those persons authorized to follow the
`
`
`
`an integrated network will include all these and more. The
`
`
`
`movements of a locator device will in fact have access to the
`
`
`
`
`only requirement is that the network include service nodes
`
`location information.
`55
`
`
`
`capable of wireless communication with the PLU.
`
`
`
`Finally, it is also desirable that any such solution provide
`
`
`
`In networks having sufficiently small nodes, such as
`
`
`
`
`the location information without requiring the intervention
`
`
`
`microcellular networks, the location of PLU 4 may be
`
`
`
`
`
`of our already overtaxed emergency services, except where
`
`
`
`
`determined with sufficient precision solely based upon its
`necessary.
`
`
`
`60 location within the coverage area 16 of one such node 20. In
`
`
`
`
`
`
`larger cells having sector antennas, the approximate location
`
`
`
`of PLU 4 may be determined based on the coverage area 18
`
`
`These needs and others are substantially met by the
`
`
`
`of the receiving sector transceiver. However, in cells larger
`
`
`
`
`system and method disclosed herein for locating a portable
`
`
`than microcells, and where more than an approximate loca-
`
`
`65 tion is desired, one or more additional steps in determining
`
`
`
`
`locator device in a communications network. The portable
`
`
`
`
`locator unit (PLU) is activated either by an external signal
`
`
`the location of PLU 4 may be used, as discussed below in
`
`
`
`
`generated at a remote activation source, such as a subscriber
`
`connection with FlG. 3.
`
`
`
`BACKGROUND OF THE INVENTION
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`SUMMARY OF THE INVENTION
`
`Cisco v. TracBeam / CSCO-1009
`Page 6 of 12
`
`

`

`5,485,163
`
`3
`
`4
`Where BTS 20 is a microcellular node, the location
`
`confirmation of the PIN, the subscriber may be prompted to
`
`
`
`
`
`
`information forwarded from BTS 20 to base station control-
`
`
`
`
`enter the form of services desired (if not already identified
`
`
`
`
`by a protocol), e.g., location, maintenance or the like.
`
`
`
`ler (BSC) 30 may be as simple as a signal containing an
`
`
`identifier like the mobile ID number (MIN) of PLU 4 and a
`
`
`
`Following a request for the location of PLU 4, service
`node ID number (NIN) for BTS 20. BSC 30 may alterna­
`
`
`5 parameters regarding PLU 4 are read from HLR 36 and used
`
`
`
`
`tively be a cellular or wireless application processor
`
`
`for activation of PLU 4. Thus, where PLU 4 is set up to be
`
`
`
`
`
`(C/WAP) connecting directly to the Public Switched Tele­
`
`
`
`activated, e.g., by an area wide page command, an activation
`
`
`
`phone Network (PSTN) 32 via a telephone switch (not
`
`
`command is forwarded to the paging system for broadcast
`
`
`
`
`shown). BSC 30 is connected to mobile service switching
`
`
`
`
`from a paging antenna (12) as a page message (signal 10) to
`
`
`
`
`center (MSC) 28. Attached to MSC 28 is a location register.
`10 PLU 4. On the other hand, where PLU 4 is only set up to
`
`
`
`
`The location register handles both visiting as well as home
`
`
`
`
`transmit and receive over cellular telephony bands, an
`
`
`
`
`location functions, depending on whether a PLU is regis­
`
`
`
`activation command will be forwarded throughout the par­
`
`tered with its home location in MSC 28 or elsewhere.
`
`
`
`
`
`ticipating cellular operating systems of the network to be
`
`
`
`
`In the illustrated embodiment a visiting location register
`
`
`transmitted from each BTS. In order to conserve system
`
`
`(VLR) 26 is attached to MSC 28. The home location register
`
`
`
`resources, one skilled in the art will appreciate that appro-
`15
`
`
`(HLR) 36 for PLU 4 can be directly coupled to PSTN 32 or
`
`
`
`
`priate algorithms may be employed to search for PLU 4,
`
`
`coupled via one or more MS Cs. While it is not essential that
`
`
`
`
`
`starting for example either at the cells in proximity to the
`
`
`
`HLR 36 or proximate some other location designated by the
`
`
`
`a VLR 26 be utilized, it is preferable in view of factors such
`
`
`subscriber as the last known location of PLU 4.
`
`
`
`
`
`as the multiple operators likely to be functioning within the
`
`communications network. For example, by utilizing infor­
`
`
`
`
`
`
`Upon receipt of the activation signal, PLU 4 switches
`20
`
`
`
`mation stored within its local VLR 26, one operator can
`
`
`
`from receive only mode to receive and transmit mode. In this
`
`
`
`mode, PLU 4 monitors the paging or control channels of
`
`
`
`identify the geographic location of BTS 20, or even subre­
`
`
`
`
`local BTSs to determine the transmission channels being
`
`
`gions such as sector coverage area 18, based on the identi­
`
`used by the BTSs. PLU 4 then registers with the strongest
`
`fying information forwarded from BTS 20. This geographic
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`
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`BTS, transmitting a location signal (LS) that includes the
`
`information, as well as the MIN of PLU 4 and the time of
`25
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`
`PLU's MIN. This information is forwarded, along with the
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`
`receipt, may then be forwarded to the HLR 36 via the MSC
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`node identification number (NIN) of receiving BTS 20, to
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`28 and PSTN 32. This simplifies the amount of information
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`the VLR 26 via BSC 30. VLR 26 translates the NIN, or other
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`that would otherwise be required to be retained at each
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`
`
`received location identifying information from BTS 20 via
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`location register throughout the network, and in some
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`
`a lookup table to determine the approximate geographic
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`instances such information (such as that identifying sector
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`location of PLU 4. This location information, along with the
`
`coverage areas) may not as a practical matter be available to 30
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`time of receipt, is then forwarded to HLR 36 using the MIN
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`a location register of a competing operator or operators of
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`address information.
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`different types of systems.
`Finally, upon receipt of the location information at HLR
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`Finally, each HLR preferably contains subscriber prefer­
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`36, the location information is forwarded, in the requested
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`ence information directing how the PLU location informa-
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`format (stored in the PLU service parameters, which include
`35
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`
`tion is to be communicated. Such preferences may include
`
`
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`subscriber preferences), to the subscriber. Thus, if the sub-
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`the means by which the information is to be communicated,
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`scriber is operating a mobile unit 6, the location information
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`e.g., by data or voice over wireline or wireless (paging or
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`
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`can be forwarded in a format applicable to the mobile unit.
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`cellular) systems to a specified end system or receiving
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`Where mobile unit 6 is an alphanumeric pager, the infor­
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`device (e.g., cellular phone), and the desired forgnat (e.g.,
`
`
`
`mation can be displayed upon a pager display. On the other
`40
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`geographical location, proximate place names (buildings),
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`
`hand, where mobile unit 6 is a cellular telephone, the
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`
`relative position and the like).
`
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`information can be forwarded in a voice format. Further,
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`One skilled in the art will also recognize that significant
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`
`where mobile unit 6 is also being tracked (e.g. by appropri­
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`extra features will be available for PLUs equipped and
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`ate request to have its location also stored at HLR 36),
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`operating within advanced operator systems such as 45
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`information can be calculated and forwarded giving the
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`NAMPS (Narrowband Advanced Mobile Phone Service).
`
`
`
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`approximate relative position (i.e. distance and direction) of
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`By use of extended protocol messages, PLUs can register
`
`PLU 4 to mobile unit 6.
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`without interfering with regular mobile registrations. They
`In the foregoing embodiment, it is envisioned that the
`
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`
`
`can also be sent instructions ( e.g. to "register" at set intervals
`
`
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`
`
`system will continuously update the location information of
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`or tune to a channel) without the PLU using uplink
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`PLU 4 until such time as the subscriber again accesses the
`50
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`resources. Further, a mobile tracker (6) can be sent location
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`
`
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`system to request an end of the search. For operation in
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`
`updates as data signals on the control channel, without the
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`cellular environments, information is updated by PLU 4
`
`need for being assigned a traffic channel.
`
`
`
`
`monitoring the cellular control channels and re-registering
`
`Turning now to FIG. 2 one embodiment for implementing
`
`each time it moves into a new cell coverage area (such as
`
`
`55 coverage area 19 ofBTS 24 in FIG. 1). One skilled in the art,
`
`
`the invention in a network including a cellular system is
`
`
`
`
`
`
`
`illustrated. The location service is initiated in this embodi­
`
`
`
`
`however, will recognize that there are various methods that
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`ment by a request from a subscriber. This request may be
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`
`
`may be used in updating the system information, and the
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`
`
`initiated by dialing an assigned number for the PLU. When
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`
`
`
`appropriate method to be used will depend upon factors such
`
`
`
`dialing into a PSTN directly from a fixed station such as
`
`
`
`
`as operating system configurations and the time criticality of
`
`telephone 8 of FIG. 1, the number for PLU 4 may need to
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`
`
`60 the location information. Thus, it is also possible to update
`
`
`
`
`
`be preceded by an appropriate system access number. When
`
`
`
`
`the location information by such methods as: resending a
`paging command so as to force PLU 4 to re-register;
`
`
`
`
`accessing the system from a wireless environment, such as
`
`
`
`from mobile unit 6 of FIG. 1, appropriate system protocols
`
`
`
`including an extended protocol command along with the
`
`may be used, such as adding a suffix to the PLU number
`
`
`
`activation command to command the PLU to send location
`
`
`
`65 signals at predetermined intervals; or even commanding
`
`
`
`identifying the call as a location request for a PLU. Once the
`
`
`
`
`PLU 4 to continuously transmit on a dedicated channel so as
`
`
`
`call has been connected, the subscriber is prompted to enter
`
`
`
`a PIN assigned for the location services for PLU 4. Upon
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`to provide a proximity homing beacon.
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`Cisco v. TracBeam / CSCO-1009
`Page 7 of 12
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`5,485,163
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`6
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`5
`to auto­subscriber. four such approaches FIG. 4 illustrates
`
`
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`
`
`In addition to using cell or sector location information, the
`
`
`
`matically activating the PLU. First, some form of boundary
`
`
`
`system of the invention may be implemented so as to
`
`
`
`
`detector may be utilized to determine when the person with
`
`
`
`
`provide more precise location information. FIG. 3 illustrates
`
`
`
`
`This without authorization. that attached PLU 104 has exited
`
`
`one such implementation; those skilled in the art will
`
`
`
`is particularly appropriate for use in buildings where a
`
`
`
`recognize that other refinements and approaches may be
`5
`
`
`
`limited number of points of egress exist and any person
`
`
`
`
`used, based upon the specific operating system (i.e., cellular,
`
`
`leaving through the exit (118) will pass close by a detector.
`
`
`
`PCS, trunk radio, in-building, etc.) in which the PLU is
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`
`
`
`with preferably be equipped PLU 104 would, in such cases,
`
`
`communicating. The embodiment of FIG. 3 is particularly
`
`
`a low power transponder for responding to continuously
`
`
`
`
`useful for locating PLUs within large cell systems, such as
`
`
`
`by the signals at detectors 108. If PLU 104 passes
`emitted
`
`
`the AMPS cellular telephone system. In such systems, the
`10
`
`
`
`
`detectors without first checking out with some system con­
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`
`
`location of a PLU within a cell may not provide sufficient
`
`
`
`
`trol, or alternatively without passing by the detectors
`
`
`information, since the cell may encompass several square
`108
`
`
`with a person carrying an electronic key 114 coded so as to
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`
`
`
`miles of territory. Consequently, use of neighboring trans­
`
`ceivers, such as BTSs 22 and 24 of FIG. 1, may be
`
`
`
`inhibit any triggering of an alarm or PLU activation com­
`
`
`mand, a boundary detector control unit 110 will then forward
`
`
`
`advantageously used. In an appropriately programmed sys­
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`
`
`15 the MlN and a protocol identifying the unauthorized exit via
`
`
`
`
`tem, upon request for more precise location information, a
`
`network 114 to the HLR 116 of PLU 104. If the parameters
`
`
`
`
`registration command may be sent across the control chan­
`
`for PLU 104 in the HLR 116 have been set to activate PLU
`
`
`nel BTS 20 to PLU 4, including an additional protocol
`
`
`are then 104 upon the occurrence of such event, instructions
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`
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`command designating the additional information desired. In
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`
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`
`of an forwarded to a local antenna 112 for transmission
`
`
`
`and for­response to one such command, PLU 4 monitors
`
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`control activation command to PLU 104. Detector 110
`
`
`wards received signal strength information regarding the 20
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`
`
`would also preferably set off a local alarm upon occurrence
`
`
`
`control channel signals from BTS 20 and the two or more
`
`
`
`next strongest channels (e.g., from BTS 22 and 24). The
`
`of the unauthorized egress.
`
`
`
`
`received signal strength information and ID' s of the respec­
`activated by Alternatively, PLU 104 may be automatically
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`
`
`
`tive BTSs are then forwarded to BSC 30 and VLR 26 for
`
`
`moving outside of a predetermined range from a monitor
`25
`
`
`
`appropriate determination of the location, based upon an
`
`
`
`monitors the106.In this embodiment, PLU 104 periodically
`
`
`
`
`appropriate algorithm and/or stored information (such as
`
`
`
`
`
`signal strength received from the monitor transmission. If
`
`
`
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`prior readings). Rather than relying upon a separate com­
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`
`
`the signal strength drops below a preset level for a prede­
`
`
`signal mand, it will be appreciated that such RSSI (received
`
`
`
`
`termined length of time, a warning signal is transmitted to
`
`
`
`
`strength indication) information can be included with each
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`
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`remainssignal strength 30 the monitor 106. If the received
`
`
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`registration when operating in an appropriately configured
`
`
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`
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`below the preset level for a further predetermined length of
`
`registration system.
`
`
`
`to automatically register time, PLU 104 is then programmed
`
`
`
`with the closest network node preferably by means of an
`
`
`
`Similarly, timing delay and phase information may be
`
`
`
`
`extended protocol attached to the registration signal. Upon
`used to more precisely locate a PLU. This may be accom­
`
`
`
`
`
`
`receiving the registration signal, the local location register
`plished by transmitting a protocol command to PLU 4 to
`
`
`
`
`35
`
`
`and BSC are instructed to retain the PLU MIN and location
`
`
`
`register with two or more node transceivers, e.g., BTS 20,
`
`
`22, and 24. When the location is based upon timing advance,
`
`
`information in a VLR and forward information about the
`
`
`
`
`activation to a network register identifying the HLR 116 of
`
`
`PLU 4 will delay each received registration command
`
`PLU 104, which identifies the HLR to the local location
`
`
`
`(including node identification) from the respective BTSs by
`
`
`
`
`register and forwards the activation and location information
`
`
`a predetermined amount of time, and then respond with a
`40
`to the HLR 116.
`
`registration signal (or return echo). Each receiving BTS will
`
`
`
`
`forward information regarding the propagation time along
`
`
`
`the Because the HLR 116 of PLU 104 will receive
`
`
`with the received MlN and the BTS's NIN. BSC 30 and
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`location information without a request for activation, HLR
`
`infor­propagation VLR 26 then process the received timing
`
`
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`
`on 116 and its local controller will search for instructions
`
`mation in conjunction with the known geographic locations
`
`
`
`in the PLU 104 parameters 45 forwarding such information
`
`
`
`
`of the BTSs to triangulate a precise geographic location for
`
`
`
`(e.g., the HLR controller stored in HLR 116. For example,
`PLU4.
`
`
`C/WAP or BSC) could be equipped to automatically dial one
`
`
`
`or more numbers preset by the subscriber to notify the
`
`Further precision may be obtained, such as when mobile
`
`
`
`
`
`subscriber of the event, the location and the time. Upon
`
`unable to unit 6 is in close proximity to PLU 4 but is still
`
`
`
`
`
`
`notification, the subscriber can then access location features
`
`identify its precise location, where a mobile unit is also
`
`
`
`50
`
`
`by use of a PIN, and commence acquisition of PLU 104 by
`
`
`
`equipped as a tracker. In such cases, the subscriber may
`
`
`
`
`use of the location features described above. In order to
`
`
`
`request the system to command PLU 4 to come up on a
`
`
`
`
`
`protect the limited system resources, however, if no response
`
`
`
`
`an dedicated traffic channel (TCH). BTS 20 then assigns
`
`
`
`
`is received by the subscriber within a preset amount of time
`
`
`
`available traffic channel, informs PLU 4 on the control
`
`
`
`the system preferably resets and a command is sent to PLU
`
`
`
`channel, and commands PLU 4 to shift to tile TCH and
`55
`104 to deactivate.
`
`
`
`transmit at short intervals. This would allow the system to
`
`
`
`
`update the PLU 4's position on a frequent basis. A precise
`activa-PLU 104 can also be provided with an automatic
`
`
`
`
`
`
`position could be obtained by measuring an uplink TCH
`
`
`
`tion feature for unauthorized removals of PLU 104 from its
`
`
`
`
`signal characteristic at additional BTS antennas. At the same
`
`
`with an wearer. In this case PLU 104 can be equipped
`
`
`
`
`in a similar manner time mobile unit 6 could be located as 60
`
`
`
`
`electronic lock or similar tamper proof device, so that any
`
`
`PLU 4, tuned to a different TCH. Preferably BSC 30 would
`
`
`
`
`tampering or removal automatically activates the registra-
`
`
`
`
`then determine the relative position of the mobile unit 6 to
`
`
`
`
`tion procedure. Preferably, the registration signal will also
`
`
`PLU 4, and send a signal to mobile unit 6 in the downlink
`
`
`
`
`include an extended protocol identifying the event as the
`
`
`with directions on how to move in order to arrive at the
`
`
`the subscriber removal of PLU 104. For such circumstances,
`
`location of PLU 4.
`
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`
`
`notifi­automatic 65 may desire PLU parameters in instructing
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`cation of emergency personnel (i.e., police) so that an
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`
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`In a further embodiment of the invention, PLU 4 may be
`
`
`immediate search can be commenced based on the last
`
`
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`
`
`activated automatically without waiting for a request from a
`
`Cisco v. TracBeam / CSCO-1009
`Page 8 of 12
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`

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`5,485,163
`
`8
`
`f) storing the PLU location information in a location
`
`g)providing the location information to an authorized
`
`7
`
`known position of the wearer (PLU 104) and such other
`6.The method of claim 5, wherein the step of providing
`
`
`
`
`
`
`identifying information (e.g., description of the child) stored
`
`
`
`location information further comprises using the signal
`
`in the parameters at HLR 116.
`
`
`
`
`quality levels of the measured control channel transmissions
`
`to locate the PLU.
`
`
`Finally, PLU 104 can also be equipped with a manual
`7.The method of claim 1, wherein the step of providing
`
`
`
`
`
`input (e.g. button 105), by which the wearer can automati-5
`
`
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`
`
`the location information further comprises dialing a number
`
`
`
`cally trigger activation. This would allow a kidnapped child
`
`
`
`
`of the receiving device and forwarding the location infor­
`
`
`
`
`to immediately activate the location features before anyone
`
`
`mation to the receiving device.
`else is even aware of the kidnapping. This is particularly
`
`8.The method of claim 7, wherein the location informa-
`
`
`
`advantageous where the child is still in a building having an
`
`
`
`10 tion is forwarded
`
`
`to the receiving device in at least one of a
`
`
`in-building service node 120; when the Location Signal,
`
`
`audio and a visual communication format.
`
`
`
`
`
`preferably with extended protocol identifying the event, is
`
`
`9.The method of claim 1, wherein the node identifier is
`
`
`received at the node 120 the controller 110 may immediately
`
`
`
`associated with the location of the first node.
`
`
`notify building security so all exits (118) can be sealed
`
`
`
`10.A method of locating a portable locator unit (PLU) in
`
`before the child is even removed from the building.
`
`
`
`a communications system comprising the steps of:
`
`
`While the invention has been described above in connec-15
`
`
`
`a)monitoring by the PLU for a remote activation signal;
`
`
`
`tion with specific embodiments, those skilled in the art will
`
`
`appreciate that there are many alternatives, modifications
`
`
`
`
`b)receiving the remote activation signal by the PLU;
`
`
`
`
`and variations thereto in light of the foregoing description.
`
`
`
`
`c)transmitting a location signal including a PLU identi­
`
`
`
`In particular, while the invention has been described in
`
`fication by the PLU;
`
`
`
`
`connection with locating lost or abducted children, it is also 20
`d)receiving the location signal at a first node of the
`
`
`
`
`
`
`applicable for the location of adults, pets, and most any
`
`
`
`communications system, and forwarding the PLU iden­
`
`
`
`object (such as cars, purses, guns, cut timber, etc.). Further,
`
`
`tification and a first node identifica