US 6,240,069 B1
`(10) Patent N0.:
`(12) United States Patent
`Alperovich et al. May 29, 2001 (:45) Date of Patent:
`
`
`
`USOO6240069B1
`
`(54) SYSTEM AND METHOD FOR
`LOCATION-BASED GROUP SERVICES
`
`(75)
`
`Inventors: Vladimir Alperovich, Dallas;
`Dipankal‘ Ray, Garland, both Of TX
`(US)
`
`........................ 455/433
`8/1999 Coyne et al.
`5,943,619 *
`9/1999 Rosenthal et a1.
`. 379/202
`5,953,400 *
`6,002,932 * 12/1999 Kingdom et a1.
`. 455/433
`
`
`- 4554456
`6:006:097 * 12/1999 Hofnfeldt et al'
`6,097,942 *
`8/2000 La1ho ................................... 455/414
`FOREIGN PATENT DOCUMENTS
`
`(73) Assignee: Ericsson Inc., Research Triangle Park,
`NC (US)
`
`12/1995 (W0) ~
`WO 95735001
`* cited by examiner
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is CXtCHdCd or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`Primary Examiner—Hassan Kizou
`Assistant Exa/niner—Inder Pal Mehra
`(74) Attorney, Agent, or Firm—Jenkens & Gilchrist, PC.
`
`(21) Appl. No.: 09/097,903
`(22)
`Filed:
`Jun. 16 1998
`’
`Int. Cl.7 ..................................................... H04Q 11/00
`(51)
`(52) US. Cl.
`.......................... 370/260; 455/416; 455/445;
`455/456; 455/518; 455/519
`(58) Field of Search ..................................... 370/260, 261,
`370/262, 263, 264, 265, 270’ 328, 329,
`331; 379/158, 201, 202, 203’ 204, 205,
`206; 455/414, 422’ 440, 433,456, 461,
`517, 518, 519
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`.. 455/38.1
`3/1994 Barry et al.
`8/1998 Dettner ................................. 455/518
`
`5,293,644
`5,797,100 *
`
`ABSTRACT
`(57)
`A telecommunications system and method is disclosed for
`defining location-based group services, which can be imple-
`mented Within a Group Call Services (GCS) node associated
`with a cellular network. When a group call is initiated, the
`GCS can send a positioning request to a Mobile Location
`Center (MLC) to locate the group members Within a speci-
`fied area. The particular location can be defined by the group
`number or the location can be prompted by the GCS. For
`each group member,
`the position of a mobile terminal
`associated With that group member is determined and the
`call is set up only to those members which the meet the
`specified area criteria. If none can be located Within the
`specified area,
`the area can be expanded at
`the callers
`ques .
`re
`t
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`26 Claims, 3 Drawing Sheets
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`LOCATION
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`LOCATION
`LOCATION
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`CALLI NC
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`PARTY
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`CELLULAR NETWORK 205
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`LYFT 1020
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`US. Patent
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`May 29, 2001
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`US 6,240,069 B1
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`US. Patent
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`May 29, 2001
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`Sheet 2 0f 3
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`US 6,240,069 B1
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`US. Patent
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`May 29, 2001
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`Sheet 3 0f3
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`US 6,240,069 B1
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`POSITION
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`BTS
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`US 6,240,069 B1
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`1
`SYSTEM AND METHOD FOR
`LOCATION-BASED GROUP SERVICES
`
`BACKGROUND OF THE PRESENT
`INVENTION
`
`1. Field of the Invention
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`10
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`The present invention relates generally to telecommuni-
`cations systems and methods for establishing a group call to
`mobile subscribers within a group, and specifically to estab-
`lishing a group call to those mobile subscribers within the
`group that are within a particular area.
`2. Background and Objects of the Present Invention
`Cellular telecommunications is one of the fastest growing
`and most demanding telecommunications applications ever.
`Today it represents a large and continuously increasing
`percentage of all new telephone subscriptions around the
`world. A standardization group, European Telecommunica-
`tions Standards Institute (ETSI), was established in 1982 to
`formulate the specifications for the Global System for ’
`Mobile Communication (GSM) digital mobile cellular radio
`system.
`With reference now to FIG. 1 of the drawings, there is
`illustrated a GSM Public Land Mobile Network (PLMN),
`such as wireless network 10, which in turn is composed of
`a plurality of areas 12, each with a Mobile Services Center
`(MSC) 14 and an integrated Visitor Location Register
`(VLR) 16 therein. The MSC/VLR areas 12, in turn, include
`a plurality of Location Areas (LA) 18, which are defined as
`that part of a given MSC/VLR area 12 in which a mobile
`station (MS) 20 may move freely without having to send
`update location information to the MSC/VLR area 12 that
`controls the LA 18. Each Location Area 12 is divided into a
`
`number of cells 22. Mobile Station (MS) 20 is the physical
`equipment, e.g., a car phone or other portable phone, used by
`mobile subscribers to communicate with the wireless net-
`work 10, each other, and users outside the subscribed
`network, both wireline and wireless.
`The MSC 14 is in communication with at least one Base
`
`Station Controller (BSC) 23, which, in turn, is in contact
`with at least one Base Transceiver Station (BTS) 24. The
`BTS 24 is the physical equipment, illustrated for simplicity
`as a radio tower, that provides radio coverage to the geo-
`graphical part of the cell 22 for which it is responsible. It
`should be understood that the BSC 23 may be connected to
`several BTSs 24, and may be implemented as a stand-alone
`node or integrated with the MSC 14. In either event, the BSC
`23 and BTS 24 components, as a whole, are generally
`referred to as a Base Station System (BSS) 25.
`With further reference to FIG. 1, the PLMN Service Area
`or wireless network 10 includes a Home Location Register
`(HLR) 26, which is a database maintaining all subscriber
`information, e. g., user profiles, current location information,
`International Mobile Subscriber Identity (IMSI) numbers,
`and other administrative information. The HLR 26 may be
`co-located with a given MSC 14, integrated with the MSC
`14, or alternatively can service multiple MSCs 14, the latter
`of which is illustrated in FIG. 1.
`
`The VLR 16 is a database containing information about
`all of the Mobile Stations 20 currently located within the
`MSC/VLR area 12. If a MS 20 roams into a new MSC/VLR
`area 12, the VLR 16 connected to that MSC 14 will request
`data about
`that Mobile Station 20 from its home HLR
`
`database 26 (simultaneously informing the HLR 26 about
`the current location of the MS 20). Accordingly, if the user
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`of the MS 20 then wants to make a call, the local VLR 16
`will have the requisite identification information without
`having to reinterrogate the home HLR 26. In the afore-
`described manner, the VLR and HLR databases 16 and 26,
`respectively, contain various subscriber information associ-
`ated with a given MS 20.
`
`Currently, additional subscriber services can be provided
`by adding an overlay to an existing cellular network 10. One
`such service is a group call, which utilizes a group call
`services (GCS) node (not shown) to set up the group calls.
`Amember of the group can dial a specific number associated
`with the group, which triggers the MSC/VLR 14/16 to route
`the call to the GCS. The GCS can then set up a call to each
`member of the group and tie the calls together in a manner
`similar to a conference call.
`
`to all group
`the GCS sets up a call
`Conventionally,
`members regardless of their location. This can lead to a
`group conference in which the members are dispersed over
`a large area, which can be a disadvantage in the situation
`where the initiator of the group call needs to reach only
`members of the group within a certain area. For example, if
`the group is a service company and the initiator of the group
`call needs to get in touch with members of the group who are
`located near a required service area, the initiator of the group
`call may prefer to only set up a call to those group members
`close to the service area in order to facilitate a quicker
`response time to the problem and to avoid interrupting those
`group members not able to reach the desired service area.
`
`It is, therefore, an object of the present invention to define
`and implement location-based group services within a cel-
`lular network.
`
`SUMMARY OF THE INVENTION
`
`The present invention is directed to telecommunications
`systems and methods for defining location-based group
`services, which can be implemented within a Group Call
`Services (GCS) node associated with a cellular network.
`When a group call is initiated, the GCS can send a posi-
`tioning request to a Mobile Location Center (MLC), request—
`ing the MLC to locate the group members within a specified
`area. The specified area can be defined by the group number
`or the location can be prompted by the GCS. For each group
`member, the position of the mobile terminal associated with
`that group member is determined, and the call is set up only
`to those members which meet the specified area criteria. If
`none can be located within the specified area, the area can
`be expanded at the callers request.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The disclosed inventions will be described with reference
`
`to the accompanying drawings, which show sample embodi-
`ments of the invention and which are incorporated in the
`specification hereof by reference, wherein:
`
`FIG. 1 is a block diagram of a conventional terrestrially-
`based wireless telecommunications system;
`
`FIG. 2 illustrates a group call to members of a group
`within a specified area in accordance with preferred embodi-
`ments of the present invention; and
`
`FIG. 3 is a block diagram showing the determination of
`the location of a mobile terminal within a cellular network.
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`US 6,240,069 B1
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`3
`DETAILED DESCRIPTION OF THE
`PRESENTLY PREFERRED EXEMPLARY
`EMBODIMENTS
`
`The numerous innovative teachings of the present appli-
`cation will be described with particular reference to the
`presently preferred exemplary embodiments. However,
`it
`should be understood that this class of embodiments pro-
`vides only a few examples of the many advantageous uses
`of the innovative teachings herein. In general, statements
`made in the specification of the present application do not
`necessarily delimit any of the various claimed inventions.
`Moreover, some statements may apply to some inventive
`features but not to others.
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`10
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`With reference now to FIG. 2 of the drawings, a call to a
`specified group of subscribers can be tailored such that the
`call is placed only to those subscribers within the group that
`are located within a certain area 260 by defining a location-
`based group 235 in a Group Call Services (GCS) node 220.
`A calling party 200 can place a call to a group of subscribers ,
`230 by dialing a number associated with the group 230.
`Thereafter, the number is analyzed by a switch 210 associ-
`ated with the calling party 200 and the call is routed to the
`GCS node 220. It should be noted that the calling party 200
`can be within the Public Switched Telephone Network or
`within a cellular network 205, the former being illustrated.
`The GCS node 220 can then either prompt the calling
`party 200 for a location code 215, which can be defined by
`the calling party, or provide a list of locations for the calling
`party to select from. The list of locations can be based upon
`select coordinates, ranges of coordinates, predefined loca-
`tion areas (either defined by the cellular network 205 or the
`calling party 200), or other
`location designations.
`Alternatively, the group number the calling party 200 dialed
`can have a location 215 associated with it. Once the calling
`party 200 enters the desired location 215, it is sent to the
`GCS 220 and stored in a memory 218 therein. The GCS 220
`then cooperates with a Mobile Location Center (MLC) 240
`to locate Mobile Stations (MSs) 250 associated with the
`group members that are within the area 260 closest to the
`specified location 215. It should be noted that the MLC 240
`can be a stand-alone node or part of the GCS 220 itself.
`As can be seen in FIG. 3 of the drawings, when the GCS
`node 380 sends a positioning request for each MS 300 within
`the group to the MLC 370, a Base Station System (BSS)
`(320 and 340) serving one of the MSs 300 to be positioned
`generates positioning data for that MS 300. For Global
`System for Mobile Communications (GSM) networks, this
`positioning data typically consists of, for example, a Timing
`Advance (TA) value from three or more separate Base
`Transceiver Stations (BTSs) (310, 320, and 330). Each TA
`value corresponds to the amount of time in advance that the
`MS 300 must send a message in order for a BTS 320 to
`receive it in the time slot allocated to that MS 300. When a
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`message is sent from the MS 300 to the BTS 320, there is
`a propagation delay, which depends upon the distance
`between the MS 300 and the BTS 320. TA values are
`
`expressed in bit periods, and can range from 0 to 63, with
`each bit period corresponding to approximately 550 meters
`between the MS 300 and the BTS 320.
`Once a TA value is determined for one BTS 320, the
`distance between the MS 300 and that particular BTS 320 is
`known, but the actual location is not. If, for example, the TA
`value equals one, the MS 300 could be anywhere along a
`radius of 550 meters. Two TA values from two BTSs, for
`example, BTSs 310 and 320, provide two possible points
`that the MS 200 could be located (where the two radiuses
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`intersect). However, with three TA values from three BTSs,
`e.g., BTSs 310, 320, and 330, the location of the MS 300 can
`be determined with a certain degree of accuracy.
`This positioning data is then delivered to a Mobile
`Switching Center (MSC) 360 serving the area that the MS
`300 is located in. Subsequently, this positioning data is
`forwarded to the MLC 370 for calculation of the geographi-
`cal location of that MS 300. Using a triangulation algorithm,
`with knowledge of the three TA values and site location data
`associated with each BTS (310, 320, and 330), the position
`of the MS 300 can be determined (with certain accuracy) by
`the MLC 370.
`
`It should be understood, however, that any estimate of
`time, distance, or angle for any cellular system 305 can be
`used, instead of the TAvalue discussed herein. For example,
`the MS 300 can have a Global Positioning System (GPS)
`receiver built into it, which is used to determine the location
`of the MS 300. In addition, the MS 300 can collect posi-
`tioning data based on the Observed Time Difference (OTD)
`between the time a BTS 320 sends out a signal and the time
`the MS 300 receives the signal. This time difference infor—
`mation can be sent to the MLC 370 for calculation of the
`
`location of the MS 300. Alternatively, the MS 300, with
`knowledge of the location of the BTS 320, can determine its
`own location.
`
`the
`With reference again to FIG. 2 of the drawings,
`location of each of the MSs 250 within the group can then
`be sent back to the GCS node 220 for comparison with the
`requested location 215. The GCS node 220 can then define
`the location—based group 235 from the original group of
`subscribers 230, and set up a group call to those subscribers
`within the area 260 associated with the specified location
`215. However, if no subscribers are within the area 260
`associated with the specified location 215, the location area
`215 defined by the calling party 200 can be expanded at the
`calling party’s 200 request.
`As will be recognized by those skilled in the art, the
`innovative concepts described in the present application can
`be modified and varied over a wide range of applications.
`Accordingly, the scope of patented subject matter should not
`be limited to any of the specific exemplary teachings
`discussed, but is instead defined by the following claims.
`What is claimed is:
`1. A telecommunications system for establishing a group
`call to at least one mobile terminal located within a specified
`area within a cellular network, said telecommunications
`system comprising:
`a group call services node having a list of subscribers
`stored therein, said list of subscribers being associated
`with said group call, said at least one mobile terminal
`being associated with one of said subscribers on said
`list of subscribers, said group call services node receiv-
`ing said group call and location information associated
`with said specified area;
`a mobile location node connected to said group call
`services node, said mobile location node determining
`the location of said at least one mobile terminal and
`
`sending the location of said at least one mobile terminal
`to said group call services node, said group call services
`node comparing the location of said at least one mobile
`terminal with said location information; and
`a mobile switching center in wireless communication with
`said at least one mobile terminal and connected to said
`
`group call services node, said mobile switching center
`connecting said group call between said group call
`services node and said at least one mobile terminal
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`US 6,240,069 B1
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`5
`w1en the location of said at least one mobile terminal
`is substantially identical to said location information.
`2. Tae telecommunications system 0 claim 1, wherein
`said group call services node receives said group call from
`a calling party, said calling party dialing a number associated
`with said list of subscribers to place said group call.
`3. Tie telecommunications system 0 claim 2, wherein
`said location information is stored within said group call
`services node, said location information being associated
`with said number said calling party dials.
`4. Tie telecommunications system 0 claim 2, wherein
`said group call services node prompts said calling party to
`enter a location code, said location code being associated
`with said location information.
`
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`5. Tie telecommunications system 0 claim 2, wherein
`said group call services node provides a list of locations to
`said calling party, said calling party sending a selected
`locatio i from said list of locations to said group call services
`node, said selected location being associated with said
`locatioa information.
`6. Tie telecommunications system of claim 1, wherein
`said location information is selected from the group con-
`sisting of: coordinates, a range of coordinates, a cellular
`locatioa area, or a group-defined location area.
`7. Tae telecommunications system of claim 1, wherein
`said group call services node sends a plurality of positioning
`requests to said mobile location node, each said positioning
`request being associated with one of said subscribers within
`said list of subscribers, said mobile location node determin-
`ing the location of a plurality of mobile terminals, each said
`mobile terminal being associated with one said subscribers,
`said at least one mobile terminal being within said plurality
`of mobile terminals.
`
`8. The telecommunications system of claim 7, wherein
`said group call services node determines a location—based
`group from said list of subscribers, said location-based
`group comprising said subscribers associated with mobile
`terminals located substantially within said specified area,
`said group call being established to each said mobile termi-
`nal associated with one of said subscribers within said
`location-based group.
`9. The telecommunications system of claim 1, wherein
`said mobile location node determines the location of said at
`
`least one mobile terminal using positioning data obtained
`from said mobile switching center.
`10. A method for establishing a group call to at least one
`mobile terminal
`located within a specified area within a
`cellular network, said method comprising the steps of:
`receiving, by a group call services node, said group call
`and location information associated with said specified
`area, said group call services node having a list of
`subscribers stored therein, said list of subscribers being
`associated with said group call, said at least one mobile
`terminal being associated with one of said subscribers
`on said list of subscribers;
`determining, by a mobile location node connected to said
`group call services node, the location of said at least
`one mobile terminal;
`sending, by said mobile location node, the location of said
`at least one mobile terminal to said group call services
`node;
`comparing, by said group call services node, the location
`of said at least one mobile terminal with said location
`information; and
`connecting, by a mobile switching center in wireless
`communication with said at least one mobile terminal
`
`6
`and connected to said group call services node, said
`group call between said group call services node and
`said at least one mobile terminal when the location of
`said at least one mobile terminal is substantially iden-
`tical to said location information.
`11. The method of claim 10, wherein said step of receiv-
`ing is performed by said group call services node receiving
`said group call from a calling party, and further comprising,
`before said step of receiving, the step of:
`dialing, by said calling party, a number associated with
`said list of subscribers to place said group call.
`12. The method of claim 11, wherein said step of receiv-
`ing said location information is performed by storing said
`location information within said group call services node,
`said location information being associated with said number
`said calling party dials.
`13. The method of claim 11, wherein said step of receiv-
`ing said location information is performed by said group call
`services node prompting said calling party to enter a location
`code, said location code being associated with said location
`information.
`
`14. The method of claim 11, wherein said step of receiv-
`ing said location information is performed by said group call
`services node providing a list of locations to said calling
`party, said calling party sending a selected location from said
`list of locations to said group call services node, said
`selected location being associated with said location infor-
`mation.
`15. The method of claim 10, wherein said location infor-
`mation is selected from the group consisting of: coordinates,
`a range of coordinates, a cellular location area, or a group-
`defined location area.
`16. The method of claim 10, further comprising, before
`said step of determining, the step of:
`sending, by said group call services node, a plurality of
`positioning requests to said mobile location node, each
`said positioning request being associated with one of
`said subscribers within said list of subscribers, said step
`of determining being performed by said mobile loca-
`tion node determining the location of a plurality of
`mobile terminals, each said mobile terminal being
`associated with one said subscribers, said at least one
`mobile terminal being within said plurality of mobile
`terminals.
`17. The method of claim 16, further comprising, before
`said step of connecting, the step of:
`determining, by said group call services node, a location-
`based group from said list of subscribers, said location-
`based group comprising said subscribers associated
`with mobile terminals located substantially within said
`specified area, said group call being established to each
`said mobile terminal associated with one of said sub-
`
`scribers within said location-based group.
`18. The method of claim 10, wherein said step of deter-
`mining is performed by said mobile location node using
`positioning data obtained from said mobile switching center.
`19. Agroup call services node for establishing a group call
`to at least one mobile terminal within a specified area within
`a cellular network, said group call services node comprising:
`a database comprising a list of subscribers, said list of
`subscribers being associated with said group call, said
`at least one mobile terminal being associated with one
`of said subscribers on said list of subscribers;
`receiving means for receiving said group call and location
`information associated with said specified area;
`sending means for sending a positioning request to locate
`said at least one mobile terminal to a mobile location
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`US 6,240,069 B1
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`node connected to said group call services node, said
`mobile location node determining the location of said at
`least one mobile terminal and sending the location of
`said at least one mobile terminal to said group call
`services node; and
`comparison means for comparing the location of said at
`least one mobile terminal with said location
`information, said group call services node establishing
`said group call to said at least one mobile terminal
`When the location of said at least one mobi e terminal
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`is substantially identical to said location information.
`20. The group call services node of claim 19, Wierein said
`receiving means receives said group call from a calling
`party, said calling party dialing a number associated with
`said list of subscribers to place said group call.
`21. The group call services node of claim 20, Wierein said
`location information is stored Within a memory Within said
`group call services node, said location information being
`associated with said number said calling party dials.
`22. The group call services node of claim 20, Wierein said '
`receiving means receives a location code from said calling
`party, said location code being associated With said location
`information.
`23. The group call services node of claim 20, Wierein said
`receiving means receives a selected location from a list of
`locations provided to said calling party by said group call
`
`
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`8
`services node, said selected location being associated With
`said location information.
`
`24. The group call services node of claim 19, Wherein said
`location information is selected from the group consisting
`of: coordinates, a range of coordinates, a cellular location
`area, or a group-defined location area.
`25. The group call services node of claim 19, wherein said
`sending means sends a plurality of positioning requests to
`said mobile location node, each said positioning request
`being associated with one of said subscribers Within said list
`of subscribers, said mobile location node determining the
`location of a plurality of mobile terminals, each said mobile
`terminal being associated with one said subscribers, said at
`least one mobile terminal being Within said plurality of
`mobile terminals.
`
`26. The group call scrviccs node of claim 25, further
`comprising determining means for determining a location-
`based group from said list of subscribers, said location-
`based group comprising said subscribers associated With
`mobile terminals located substantially Within said specified
`area, said group call being established to each said mobile
`terminal associated With one of said subscribers Within said
`
`location-based group.
`
`’
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